Initial revision
authoraleph1 <aleph1>
Mon, 20 May 2002 17:41:34 +0000 (17:41 +0000)
committeraleph1 <aleph1>
Mon, 20 May 2002 17:41:34 +0000 (17:41 +0000)
29 files changed:
Documentation/sv9349341.gif [new file with mode: 0644]
Documentation/sv9929930.gif [new file with mode: 0644]
Documentation/taffs-todo.html [new file with mode: 0644]
Documentation/tnode.drawing.sda [new file with mode: 0644]
Documentation/yaffs-0.3.html [new file with mode: 0644]
Documentation/yaffs-notes2.html [new file with mode: 0644]
Documentation/yaffs_report20020211.html [new file with mode: 0644]
Documentation/yaffs_report20020304.html [new file with mode: 0644]
Makefile [new file with mode: 0644]
devextras.h [new file with mode: 0644]
snMakefile [new file with mode: 0644]
utils/Makefile [new file with mode: 0644]
utils/mkyaffs [new file with mode: 0755]
utils/mkyaffs.c [new file with mode: 0644]
yaffs-header.c [new file with mode: 0644]
yaffs_fileem.c [new file with mode: 0644]
yaffs_fs.c [new file with mode: 0644]
yaffs_guts.c [new file with mode: 0644]
yaffs_guts.h [new file with mode: 0644]
yaffs_mtdif.c [new file with mode: 0644]
yaffs_mtdif.h [new file with mode: 0644]
yaffs_nandemul.h [new file with mode: 0644]
yaffs_ramem.c [new file with mode: 0644]
yaffs_super.c [new file with mode: 0644]
yaffsdev [new file with mode: 0755]
yaffsdev.c [new file with mode: 0644]
yaffsdev.proj [new file with mode: 0644]
yaffsinterface.h [new file with mode: 0644]
yportenv.h [new file with mode: 0644]

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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
+<HTML>
+<HEAD>
+       <META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=iso-8859-1">
+       <TITLE></TITLE>
+       <META NAME="GENERATOR" CONTENT="StarOffice/5.2 (Linux)">
+       <META NAME="AUTHOR" CONTENT=" ">
+       <META NAME="CREATED" CONTENT="20020501;19062800">
+       <META NAME="CHANGEDBY" CONTENT=" ">
+       <META NAME="CHANGED" CONTENT="20020513;21165500">
+</HEAD>
+<BODY>
+<P>YAFFS Todo</P>
+<OL>
+       <LI><P>Locking</P>
+       <LI><P>Fix statfs. df does not give correct results.</P>
+       <LI><P>Fix disk full condition. 
+       </P>
+       <LI><P>ECC and write failure handling.</P>
+       <LI><P>Add symlinks and links to VFS interface.</P>
+       <LI><P>Add memory mapping (to allow file execution).</P>
+       <LI><P>Test with nandemul mtd.</P>
+       <LI><P>Discuss improved NAND page interface with mtd group.</P>
+</OL>
+<P>NANDEmul MTD</P>
+<OL>
+       <LI><P>Complete and test.</P>
+       <LI><P></P>
+       <P></P>
+</OL>
+<P><BR><BR>
+</P>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
+<HTML>
+<HEAD>
+       <META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=iso-8859-1">
+       <TITLE></TITLE>
+       <META NAME="GENERATOR" CONTENT="StarOffice/5.2 (Linux)">
+       <META NAME="AUTHOR" CONTENT=" ">
+       <META NAME="CREATED" CONTENT="20011219;22024300">
+       <META NAME="CHANGEDBY" CONTENT=" ">
+       <META NAME="CHANGED" CONTENT="20020128;21063000">
+</HEAD>
+<BODY>
+<H1 ALIGN=CENTER>YAFFS (yet another Flash File System)</H1>
+<H4 ALIGN=LEFT>Version 0.3<BR>Charles Manning (and Wookey), December 2001</H4>
+<P ALIGN=LEFT><BR><BR>
+</P>
+<H2>Revision History</H2>
+<TABLE WIDTH=548 BORDER=1 CELLPADDING=4 CELLSPACING=3>
+       <COL WIDTH=88>
+       <COL WIDTH=72>
+       <COL WIDTH=350>
+       <THEAD>
+               <TR>
+                       <TH WIDTH=88 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">V0.0</P>
+                       </TH>
+                       <TH WIDTH=72 VALIGN=BOTTOM SDVAL="37245" SDNUM="5129;0;D/MM/YY">
+                               <P ALIGN=LEFT STYLE="font-style: normal">20/12/01</P>
+                       </TH>
+                       <TH WIDTH=350 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">First draft</P>
+                       </TH>
+               </TR>
+       </THEAD>
+       <TBODY>
+               <TR>
+                       <TD WIDTH=88 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">V0.1</P>
+                       </TD>
+                       <TD WIDTH=72 VALIGN=BOTTOM SDVAL="37267" SDNUM="5129;0;D/MM/YY">
+                               <P ALIGN=LEFT STYLE="font-style: normal">11/01/02</P>
+                       </TD>
+                       <TD WIDTH=350 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">Minor corrections &amp;
+                               cosmetics.<BR>Change use of data status byte.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=88 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">V0.2</P>
+                       </TD>
+                       <TD WIDTH=72 VALIGN=BOTTOM SDVAL="37284" SDNUM="5129;0;D/MM/YY">
+                               <P ALIGN=RIGHT STYLE="font-style: normal">28/01/02</P>
+                       </TD>
+                       <TD WIDTH=350 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">Added observations about
+                               inodes, file headers and hard links.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=88 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">V0.3</P>
+                       </TD>
+                       <TD WIDTH=72 VALIGN=BOTTOM SDVAL="37285" SDNUM="5129;0;D/MM/YY">
+                               <P ALIGN=RIGHT STYLE="font-style: normal">26/02/02</P>
+                       </TD>
+                       <TD WIDTH=350 VALIGN=TOP>
+                               <P ALIGN=LEFT STYLE="font-style: normal">W:Added some general 
+                               observations on compatibility, partitions and bootloading.</P>
+                       </TD>
+               </TR>
+       </TBODY>
+</TABLE>
+<P ALIGN=LEFT><BR><BR>
+</P>
+<H2>Scope</H2>
+<P>The purpose of this document is to outline a potential
+NAND-friendly file system for Linux.</P>
+<H2>Background</H2>
+<P>There are already various flash-file systems (FFSs) or block
+drivers for flash (on top of which a regular FS runs). There are pros
+and cons with all of these. 
+</P>
+<P>Flash memory has quite a few constraints which will not be
+addressed here. Various approaches are available to work around these
+constraints to provide a file system. It is important to recognise
+that &quot;flash&quot; includes both NOR and NAND flash which have
+different sets of constraints. It is easy to be mislead by the
+generic term &quot;flash&quot; into thinking that approaches
+appropriate for NOR flash are immediately suitable for NAND flash.</P>
+<P>The NAND block drivers (eg. SmartMedia [currently not available
+for Linux] and DiskOnChip NFTL) typically use FAT16 as the file
+system. This isn't too robust and nor is it that flash-friendly.
+These block drivers provide a logical to physical mapping layer to
+emulate rewritable blocks that look like disk sectors. When used with
+FAT16, these file systems work reasonably well. They have a low
+memory footprint and scale well. Like all FAT based systems they are
+prone to corruption (&quot;lost clusters etc&quot;).</P>
+<P>The other approach is to design an entire file system which does
+not work through a block driver layer and is flash-friendly. This
+allows more scope to work around issues.</P>
+<P>Currently, two Linux file systems that support NOR flash very well
+are JFFS and its derivative JFFS2. Both of these are based on the
+principles of journaling (hence the leading J) which significantly
+increases robustness - a particularly important feature in embedded
+systems. Unfortunately neither of these file systems scale
+particularly well in both boot time and RAM usage. Scaling is
+particularly relevant when one considers that a 16MB NOR array would
+be considered large while a 128MB NAND is available as a single chip.</P>
+<P>JFFS requires a RAM-based jffs_node structure for each journalling
+node in the flash. Each of these nodes is 48 bytes. JFFS2 makes a
+significant improvement here by reducing the equivalent structure
+(jffs2_raw_node_ref) to 16 bytes. Still, at say an average node-size
+of 512 bytes, a 128MB NAND might need 250000 of these ... 4MB!</P>
+<P>Both JFFS and JFFS2 require scanning the flash array at boot time
+to find the journaling nodes and determine the file structures. Since
+NAND is large, slow, serially accessed and needs ECC this does not
+scale well and will take an unacceptably long boot time for the
+target systems. As a thumb-suck, the scanning of a 128MB NAND array
+might take approx 25 seconds.</P>
+<P>The intentions of the design sketched here are:</P>
+<UL>
+       <LI><P>Be NAND-flash friendly.</P>
+       <LI><P>Robustness through journaling strategies.</P>
+       <LI><P>Significantly reduce the RAM overheads and boot times
+       associated with JFFSx.</P>
+</UL>
+<p>This FS is intended primarily for internal NAND rather than removable NAND
+(SM cards). On removable SM cards Smartmedia compatibility is likely to be
+important so SM/FAT will normally be used, although of course YAFFS makes a
+lot of sense if reliability is more important than compatibility.</p>
+
+<H2>Overview</H2>
+<P>Here follows a simplified overview of YAFFS.</P>
+<P>YAFFS uses a physical flash format similar to SmartMedia. This is
+done for various reasons:</P>
+<UL>
+       <LI><P>Some of the formatting, eg placement of bad block markers is
+       determined by the NAND manufacturers and can't be changed.</P>
+       <LI><P>Potential to reuse code.</P>
+       <LI><P>If it ain't broke don't fix.</P>
+</UL>
+<P>Some of the fields are obviously different to reflect the
+different usage. Despite the similarities YAFFS is not actually compatible
+with SM/FAT. SM cards need to be reformatted to switch from using SM/FAT to
+YAFFS or vice versa.</P>
+<P>File data is stored in fixed size &quot;chunks&quot; consistent
+with the size of a page (ie. 512 bytes). Each page is marked with a
+file id and chunk number. These tags are stored in the &quot;spare
+data&quot; region of the flash. The chunk number is determined by
+dividing the file position by the chunk size.</P>
+<P>When data in a file is overwritten, the relevant chunks are
+replaced by writing new pages to flash containing the new data but
+the same tags. The overwritten data is marked as &quot;discarded&quot;.
+</P>
+<P>File &quot;headers&quot; are stored as a single page, marked so as
+to be differentiated from data pages.</P>
+<P>Pages are also marked with a short (2 bit) serial number that
+increments each time the page at this position is incremented. The
+reason for this is that if power loss/crash/other act of demonic
+forces happens before the replaced page is marked as discarded, it is
+possible to have two pages with the same tags. The serial number is
+used to arbitrate.</P>
+<P>A block containing only discarded pages (termed a <I>dirty block</I>)
+is an obvious candidate for garbage collection. Otherwise valid pages
+can be copied off a block thus rendering the whole block discarded
+and ready for garbage collection.</P>
+<P>In theory you don't need to hold the file structure in RAM... you
+could just scan the whole flash looking for pages when you need them.
+In practice though you'd want better file access times than that! The
+mechanism proposed here is to have a list of __u16 page addresses
+associated with each file. Since there are 2<SUP>18</SUP> pages in a
+128MB NAND, a __u16 is insufficient to uniquely identify a page but
+is does identify a group of 4 pages - a small enough region to search
+exhaustively. This mechanism is clearly expandable to larger NAND
+devices - within reason. The RAM overhead with this approach is
+approx 2 bytes per page - 512kB of RAM for a whole 128MB NAND.</P>
+<P>Boot-time scanning to build the file structure lists should
+require just one pass reading NAND. Since only the the spare data
+needs to be read, this should be relatively fast ( approx 3 seconds
+for 128MB). Improvements can be achieved by partitioning the NAND.
+ie. mount the critical partition first then mount the data partition
+afterwards.</P>
+<P>Various runtime improvements can be achieved by changing the
+&quot;chunk size&quot; to 1024 bytes or more. However this would
+likely reduce flash efficiency. As always, life is a compromise....</P>
+<P><BR><BR>
+</P>
+<H3>Spare area details</H3>
+<P>The following table summarizes the layout of the spare area of
+each page.</P>
+<TABLE WIDTH=674 BORDER=1 CELLPADDING=4 CELLSPACING=3>
+       <COL WIDTH=96>
+       <COL WIDTH=249>
+       <COL WIDTH=291>
+       <THEAD>
+               <TR VALIGN=TOP>
+                       <TH WIDTH=96>
+                               <P>Byte #</P>
+                       </TH>
+                       <TH WIDTH=249>
+                               <P>SmartMedia usage</P>
+                       </TH>
+                       <TH WIDTH=291>
+                               <P>YAFFS usage</P>
+                       </TH>
+               </TR>
+       </THEAD>
+       <TBODY>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=96>
+                               <P>0..511</P>
+                       </TD>
+                       <TD WIDTH=249>
+                               <P>Data</P>
+                       </TD>
+                       <TD WIDTH=291>
+                               <P>Data. either file data or file header depending on tags</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=96>
+                               <P>512..515</P>
+                       </TD>
+                       <TD WIDTH=249>
+                               <P>Reserved</P>
+                       </TD>
+                       <TD WIDTH=291>
+                               <P>Tags</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=96 VALIGN=BOTTOM SDVAL="516" SDNUM="5129;">
+                               <P ALIGN=RIGHT>516</P>
+                       </TD>
+                       <TD WIDTH=249 VALIGN=TOP>
+                               <P>Data status byte. Not used in SM code from Samsung</P>
+                       </TD>
+                       <TD WIDTH=291 VALIGN=TOP>
+                               <P>Data status byte. If more than 4 bits are zero, then this page
+                               is discarded.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=96 VALIGN=BOTTOM SDVAL="517" SDNUM="5129;">
+                               <P ALIGN=RIGHT>517</P>
+                       </TD>
+                       <TD WIDTH=249 VALIGN=TOP>
+                               <P>Block status byte</P>
+                       </TD>
+                       <TD WIDTH=291 VALIGN=TOP>
+                               <P>Block status byte</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=96>
+                               <P ALIGN=LEFT>518..519</P>
+                       </TD>
+                       <TD WIDTH=249>
+                               <P>Block address</P>
+                       </TD>
+                       <TD WIDTH=291>
+                               <P>Tags</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=96>
+                               <P ALIGN=LEFT>520..522</P>
+                       </TD>
+                       <TD WIDTH=249>
+                               <P>ECC on second 256 bytes part of data</P>
+                       </TD>
+                       <TD WIDTH=291>
+                               <P>ECC on second 256 bytes of data</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=96>
+                               <P ALIGN=LEFT>523..524</P>
+                       </TD>
+                       <TD WIDTH=249>
+                               <P>Block address</P>
+                       </TD>
+                       <TD WIDTH=291>
+                               <P>Tags</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=96>
+                               <P ALIGN=LEFT>525..527</P>
+                       </TD>
+                       <TD WIDTH=249>
+                               <P>ECC on first 256 bytes part of data</P>
+                       </TD>
+                       <TD WIDTH=291>
+                               <P>ECC on first 256 bytes part of data</P>
+                       </TD>
+               </TR>
+       </TBODY>
+</TABLE>
+<P><BR><BR>
+</P>
+<P>The block status is a reserved value that shows whether the block
+is damaged.</P>
+<P>The data status tracks whether the page is valid. If less than 4
+bits are zero, then the page is valid otherwise it is discarded.</P>
+<P>There are 8 bytes (64 bits) for use by YAFFS tags. This is
+partitioned as follows:</P>
+<TABLE WIDTH=596 BORDER=1 CELLPADDING=4 CELLSPACING=3>
+       <COL WIDTH=146>
+       <COL WIDTH=423>
+       <THEAD>
+               <TR VALIGN=TOP>
+                       <TH WIDTH=146>
+                               <P>Number of bits</P>
+                       </TH>
+                       <TH WIDTH=423>
+                               <P>Usage</P>
+                       </TH>
+               </TR>
+       </THEAD>
+       <TBODY>
+               <TR>
+                       <TD WIDTH=146 VALIGN=BOTTOM SDVAL="18" SDNUM="5129;">
+                               <P ALIGN=RIGHT>18</P>
+                       </TD>
+                       <TD WIDTH=423 VALIGN=TOP>
+                               <P>18-bit file id. ie. Limit of 2<SUP>18</SUP> (over 260000)
+                               files. File id 0 is not valid and indicates a deleted page. File
+                               Id 0x3FFFF i is also not valid.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=146 VALIGN=BOTTOM SDVAL="2" SDNUM="5129;">
+                               <P ALIGN=RIGHT>2</P>
+                       </TD>
+                       <TD WIDTH=423 VALIGN=TOP>
+                               <P ALIGN=LEFT>2-bit serial number.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=146 VALIGN=BOTTOM SDVAL="20" SDNUM="5129;">
+                               <P ALIGN=RIGHT>20</P>
+                       </TD>
+                       <TD WIDTH=423 VALIGN=TOP>
+                               <P>20-bit page id within file. Limit of 2<SUP>20</SUP> pages per
+                               file. ie. over 500MB file max size. Page id 0 means the file
+                               header for this file.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=146 VALIGN=BOTTOM SDVAL="10" SDNUM="5129;">
+                               <P ALIGN=RIGHT>10</P>
+                       </TD>
+                       <TD WIDTH=423 VALIGN=TOP>
+                               <P>10-bit counter of the number of bytes used in the page.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=146 VALIGN=BOTTOM SDVAL="12" SDNUM="5129;">
+                               <P ALIGN=RIGHT>12</P>
+                       </TD>
+                       <TD WIDTH=423 VALIGN=TOP>
+                               <P>12-bit ECC on tags.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=146 VALIGN=BOTTOM SDVAL="2" SDNUM="5129;">
+                               <P ALIGN=RIGHT>2</P>
+                       </TD>
+                       <TD WIDTH=423 VALIGN=TOP>
+                               <P>Unused. Keep as 1.</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=146 VALIGN=BOTTOM SDVAL="64" SDNUM="5129;">
+                               <P ALIGN=RIGHT><B>64</B></P>
+                       </TD>
+                       <TD WIDTH=423 VALIGN=TOP>
+                               <P><B>Total</B></P>
+                       </TD>
+               </TR>
+       </TBODY>
+</TABLE>
+<P><BR><BR>
+</P>
+<P>A bit of explanation on the usage of some of these fields:</P>
+<P>file Id is synonymous with inode.</P>
+<P>The serial number is incremented each time a page with the same
+file_id:page_id is rewritten (because of data changes or copy during
+garbage collection). When a page is replaced, there is a brief period
+during which there are two pages with the same id. The serial number
+resolves this. Since there should never be a difference of less than
+more than one, a two-bit counter is sufficient to determine which is
+the current page.</P>
+<P>When the page is rewritten, the file id, these data status byte
+and the 12-bit ECC are all written to zero.</P>
+<P>The byte counter indicates how many bytes are valid in this page.
+Since the page would not exist if it contains zero bytes, this field
+should thus hold 512 for all pages except the last page in the file.
+The use of counters means that the file length integrity is preserved
+while the file is open without having to constantly update the file
+length in the file header. The file header only needs to be refreshed
+when the file is closed (rather than whenever it is appended to).
+This field is wide enough to allow expansion to 1024-byte &quot;chunks&quot;.</P>
+<P>File &quot;headers&quot; come in two flavours:</P>
+<UL>
+       <LI><P>file info ( the mode, ower id, group id, length,...)</P>
+       <LI><P>the hard link(s) that refers to the file.</P>
+</UL>
+<P>A directory also appears as a file (ie. has an inode and hard
+link(s)) but has no data.</P>
+<P>The 12-bit ECC applies to only the tag data uses a similar
+algorithm to the 22-bit ECCs used for file system data. They are kept
+independent.</P>
+<H3>RAM data details</H3>
+<P>Block management details are reasonably obvious and, I feel, don't
+need to be addressed here apart from stating that there will be a
+structure to track block status (eg. number of pages in use, failed
+blocks, and which are candidates for garbage collection etc).</P>
+<P>The files need an indexing structure of sorts to locate and track
+the pages in the file. Some sort of tree structure should work rather
+well. The look-up needs to be quite efficient in both CPU time and
+space.</P>
+<H3>Page allocation and garbage collection</H3>
+<P>Pages are allocated sequentially from the currently selected
+block. When all the pages in the block are filled, another clean
+block is selected for allocation. At least two or three clean blocks
+are reserved for garbage collection purposes. If there are
+insufficient clean blocks available, then a dirty block ( ie one
+containing only discarded pages) is erased to free it up as a clean
+block. If no dirty blocks are available, then the dirtiest block is
+selected for garbage collection.</P>
+<P>Garbage collection is performed by copying the valid data pages
+into new data pages thus rendering all the pages in this block dirty
+and freeing it up for erasure. I also like the idea of selecting a
+block at random some small percentage of the time - thus reducing the
+chance of wear differences.</P>
+<P>Relative to NOR, NAND writes and erases very fast. Therefore
+garbage collection might be performed on-demand (eg. during a write)
+without significant degradation in performance. Alternatively garbage
+collection might be delegated to a kernel tasklet.</P>
+<P>Relative to JFFSx, the garbage collection presented here is
+incredibly simple - thanks mainly to the use of fixed-size pages
+instead of journaling nodes.</P>
+<H3>Flash writing</H3>
+<P>As presented here, YAFFS only writes to the page's data area once
+and to the spare area twice (once when new page is written and once when it
+gets stomped on) before an erasure. This is within the limits of the most
+restrictive NAND flashes.</P>
+
+<H3>Wear leveling</H3>
+<P>No wear leveling is explicitly used here. Instead we rely on two
+&quot;strategies&quot;:</P>
+<UL>
+       <LI><P>Reserving some blocks to cater for failure. You need to do
+       this anyway with NAND. The main purpose behind wear leveling is to
+       prevent some blocks getting more wear and failing. Since we expect,
+       and handle, failure this is no longer as important.</P>
+       <LI><P>The infrequent random block selection should prevent low-wear
+       blocks getting &quot;stuck&quot;.</P>
+</UL>
+<h3>Partitioning</h3>
+<p> Partitioning is not included in this spec, but could be added if
+required.</p>
+<h3>Bootloading</h3>
+<p>Bootloaders cannot just read files direct from NAND due to the high
+probability of bad blocks. Because YAFFS is quite simple it will be
+relatively straightforward for bootloaders to read from it (eg reading a
+kernel).</p>
+
+<H3>Conclusion</H3>
+<P>YAFFS is very simple. It is also NAND-friendly, is relatively
+frugal with resources (especially RAM) and boots quickly. Like JFFSx
+it has journaling which makes it far more robust than FAT.</P>
+<P>While it might seem high-risk to develop YAFFS, it is probably
+about the same amount of effort as implementing changes to JFFS to
+get it to work effectively within the constraints of NAND. A
+resulting JFFSx system would still require significant amounts of RAM
+and have long boot times.</P>
+<P>While YAFFS is indeed a new file system internally, much of the
+file system glue code (including inode management, link management
+etc) can likely be stolen from JFFSx. 
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
+<HTML>
+<HEAD>
+       <META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=iso-8859-1">
+       <TITLE></TITLE>
+       <META NAME="GENERATOR" CONTENT="StarOffice/5.2 (Linux)">
+       <META NAME="AUTHOR" CONTENT=" ">
+       <META NAME="CREATED" CONTENT="20020429;14311100">
+       <META NAME="CHANGEDBY" CONTENT=" ">
+       <META NAME="CHANGED" CONTENT="20020513;21133100">
+</HEAD>
+<BODY>
+<H1 ALIGN=CENTER>YAFFS Development Notes</H1>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<H3>Build options</H3>
+<P>Yaffs can be built as either a kernel module (ie. a Linux file
+system) or as an application.</P>
+<P>Of course the goal is to build yaffs as a file system running on
+top of real NAND flash, but yaffs can be built to run on a RAM
+emulation layer for in-kernel testing without NAND flash in the
+system.</P>
+<P>Building as an application allows the yaffs_guts algorithms to be
+tested/debugged in a more friendly debugging environment. The test
+harness is in yaffsdev.c</P>
+<H3>Trying it out</H3>
+<P>YAFFS can be built to run with either mtd or RAM emulation, or
+both. The file system that interfaces to mtd is called <B>yaffs</B>,
+the file system that uses internal ram is called <B>yaffsram</B>.
+YAFFS simultaneously supports both if they are enabled.</P>
+<OL>
+       <LI><P>Hack the Makefile and change the KERNELDIR define to your
+       kernel directory.</P>
+       <LI><P>If you don't have mtd support in your kernel, then you might
+       need to turn off USE_MTD otherwise the yaffs module might not load.</P>
+       <LI><P>Type <B><FONT FACE="Courier, monospace">make clean; make</FONT></B>
+       to build yaffs</P>
+       <LI><P>Load yaffs as a module by typing <B><FONT FACE="Courier, monospace">/sbin/insmod
+       yaffs.o</FONT></B> (ya gotta be root!).</P>
+       <LI><P>Create a mount point eg. <B><FONT FACE="Courier, monospace">mkdir
+       /mnt/y</FONT></B></P>
+       <LI><P>To mount the RAM emulation version of yaffs,  <B><FONT FACE="Courier, monospace">mount
+       -t yaffsram none /mnt/y</FONT></B></P>
+       <LI><P><FONT FACE="Courier, monospace"><SPAN STYLE="font-weight: medium"><FONT FACE="Times, serif">Alternatively,
+       to mount the mtd version of yaffs,</FONT></SPAN><B> mount -t yaffs
+       /dev/mtd0 /mnt/y</B></FONT></P>
+</OL>
+<P><BR><BR>
+</P>
+<H3>YAFFS Data structures</H3>
+<P>All data types are defined in yaffs_guts.h</P>
+<P>Yaffs uses the following major objects:</P>
+<UL>
+       <LI><P>yaffs_Object: A yaffs_Object can be a file, directory,
+       symlink or hardlink. The yaffs_Objects &quot;know&quot; about their
+       corresponding yaffs_ObjectHeader in NAND and the data for that
+       object. yaffs_Objects also bind together the directory structure as
+       follows:</P>
+       <LI><P>parent: pointer to the yaffs_Object that is a parent of this
+       yaffs_Object in the directory structure.</P>
+       <LI><P>siblings: this field is used to link together a list of all
+       the yaffs_Objects in the same directory.</P>
+       <LI><P>children: if the object is a directory, then children holds
+       the head of the list of objects in the directory.</P>
+       <LI><P>yaffs_Tnode: yaffs_Tnodes form a tree structure that speeds
+       up the search for data chunks in a file. As the file grows in size,
+       the levels increase. The Tnodes are a constant size (32 bytes).
+       Level 0 (ie the lowest level) comprise 16 2-byte entries giving an
+       index used to search for the chunkId. Tnodes at other levels
+       comprise 8 4-byte pointer entries to other tnodes lower in the tree.</P>
+       <LI><P>yaffs_Device: this holds the device context and is in some
+       ways analogous to the VFS superblock. It stores the data used to
+       access the mtd as well as function pointers to access the NAND data.</P>
+</UL>
+<P>The Tnodes and Objects are allocated in groups to reduce memory
+allocation/freeing overheads. Freed up tnodes and objects are kept in
+a free list and re-used.</P>
+<H3>yaffs_Object</H3>
+<P><BR><BR>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>struct
+ yaffs_ObjectStruct</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>{</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u8
+fake:1;                    // A fake object has no presence on NAND.</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u8
+renameAllowed:1;           // Are we allowed to rename it?</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u8
+unlinkAllowed:1;           // Are we allowed to unlink it?</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u8
+dirty:1;                   // the object needs to be written to flash</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u8
+valid:1;                   // When the file system is being loaded up, this </FONT></FONT>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>                          
+   // object might be created before the data</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>                          
+   // is available (ie. file data records appear before the header).</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u8
+serial;                    // serial number of chunk in NAND. Store here so we
+don't have to</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>                          
+   // read back the old one to update.</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u16
+sum;               // sum of the name to speed searching</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  struct
+yaffs_DeviceStruct *myDev; // The device I'm on</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>                                                          </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  struct
+list_head hashLink;    // list of objects in this hash bucket</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>                                                  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><BR>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  struct
+list_head hardLinks; // all the equivalent hard linked objects</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>                          //
+live on this list</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  //
+directory structure stuff</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  struct
+yaffs_ObjectStruct  *parent;   //my parent directory</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  struct
+list_head siblings;              // siblings in a directory</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>                                  
+// also used for linking up the free list</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>          </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  //
+Where's my data in NAND?</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  int
+chunkId;               // where it lives</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+objectId;              // the object id value</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_mode;       // protection</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_uid;        // user ID of owner</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_gid;        // group ID of owner </FONT></FONT>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_atime;      // time of last access</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_mtime;      // time of last modification</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_ctime;      // time of last change</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><BR>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  yaffs_ObjectType
+variantType;</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  yaffs_ObjectVariant
+variant;</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>};</FONT></FONT></P>
+<P><BR><BR>
+</P>
+<P>Obvious stuff skipped....</P>
+<P>fake, renameAllowed, unlinkAllowed are special flags for handling
+&quot;fake&quot; objects which live in the file system but do not
+live on NAND. Currently there are only two such objects: the root
+object and the lost+found directory. None of these may be renamed or
+unlinked.</P>
+<P>serial, sum: see yaffs_ObjectHeader.</P>
+<P>dirty indicates that the object's contents has changed and a new
+yaffs_ObjectHeader must be written to flash.</P>
+<P>valid indicates that the object has been loaded up. This is only
+used during scanning (yaffs_Scan()) since we can know of an object's
+existance - and thus need to create the object header - before we
+encounter the associated yaffs_ObjectHeader.</P>
+<P>hashlink is a list of Objects in the same hash bucket. 
+</P>
+<P>The four variants hold extra info:</P>
+<P>Files hold the file size and the top level and pointer to the
+tnode tree for the file.</P>
+<P>Directories hold a list of children objects.</P>
+<P>Symlinks hold a pointer to the alias string. This is probably
+inefficient, but that probably does not matter since we don't expect
+to see many of these. 
+</P>
+<P>Hardlinks hold information to identify the equivalent object.</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<H3>File structure (tnodes)</H3>
+<P>File structures are done with a tiered indexing structure</P>
+<P><BR><BR>
+</P>
+<P><IMG SRC="sv9349341.gif" NAME="Graphic2" ALIGN=LEFT WIDTH=491 HEIGHT=294 BORDER=0><BR CLEAR=LEFT><BR><BR>
+</P>
+<P>The file structure is maintained by a tree structure. Depending
+where it is in the tree, each tree node (<B><I>tnode</I></B>) (the
+blue/things) holds either:</P>
+<UL>
+       <LI><P>.... if it is at the lowest level, then 16 __u16s which
+       identify the page.</P>
+       <LI><P>.... if it is at a higher level (ie an internal tnode), then
+       8 pointers to lowest-level tnodes.</P>
+</UL>
+<P>When the file starts out, it is assigned only one low-level tnode.
+When the file expands past what a single tnode can hold, then it is
+assigned a second tnode and an internal node is added to point to the
+two tnodes. As the file grows, more low-level tnodes and high level
+tnodes are added.</P>
+<P>Traversing the tnode tree to find a particular page in a file is
+quite simple: each internal tnode is selected from by using 3 bits of
+the page offset in the file. The level 0 page resolves 4 bits.</P>
+<P>For example, finding page 0x235 (ie. the one starting at file
+position 0x46800 would proceed as follows:</P>
+<P>0x235 is 0000001000110101, partitioned as follows.
+000.000.100.011.0101</P>
+<TABLE WIDTH=496 BORDER=1 CELLPADDING=4 CELLSPACING=3>
+       <COL WIDTH=140>
+       <COL WIDTH=160>
+       <COL WIDTH=158>
+       <THEAD>
+               <TR VALIGN=TOP>
+                       <TH WIDTH=140>
+                               <P>Level</P>
+                       </TH>
+                       <TH WIDTH=160>
+                               <P>Bits</P>
+                       </TH>
+                       <TH WIDTH=158>
+                               <P>Selected value</P>
+                       </TH>
+               </TR>
+       </THEAD>
+       <TBODY>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=140>
+                               <P>3 or more if they exist</P>
+                       </TD>
+                       <TD WIDTH=160>
+                               <P>&gt;= 10</P>
+                       </TD>
+                       <TD WIDTH=158>
+                               <P>Zero</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=140 VALIGN=BOTTOM SDVAL="2" SDNUM="5129;">
+                               <P ALIGN=RIGHT>2</P>
+                       </TD>
+                       <TD WIDTH=160 VALIGN=TOP>
+                               <P ALIGN=LEFT>9 to 7</P>
+                       </TD>
+                       <TD WIDTH=158 VALIGN=TOP>
+                               <P>100 binary = 4</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=140 VALIGN=BOTTOM SDVAL="1" SDNUM="5129;">
+                               <P ALIGN=RIGHT>1</P>
+                       </TD>
+                       <TD WIDTH=160 VALIGN=TOP>
+                               <P ALIGN=LEFT>6 to 4</P>
+                       </TD>
+                       <TD WIDTH=158 VALIGN=TOP>
+                               <P>011 binary = 3</P>
+                       </TD>
+               </TR>
+               <TR>
+                       <TD WIDTH=140 VALIGN=BOTTOM SDVAL="0" SDNUM="5129;">
+                               <P ALIGN=RIGHT>0</P>
+                       </TD>
+                       <TD WIDTH=160 VALIGN=TOP>
+                               <P ALIGN=LEFT>3 to 0</P>
+                       </TD>
+                       <TD WIDTH=158 VALIGN=TOP>
+                               <P>0101 binary = 5</P>
+                       </TD>
+               </TR>
+       </TBODY>
+</TABLE>
+<P><BR><BR>
+</P>
+<P>Free tnodes are stored in a list. When the list is exhausted, more
+are allocated.</P>
+<P>Each tnode takes 32 bytes. Each file needs at least one level 0
+tnode. How many do we need? A full 16MB file system needs at least
+16MB/512/16 = 2000 level zero tnodes. More for internal tnodes. More
+for files smaller than optimal.</P>
+<P>The tree grows as required. When the file is resized to a smaller
+size then it is pruned.</P>
+<P><BR><BR>
+</P>
+<H3>NAND data</H3>
+<P>Data is stored on NAND in &quot;chunks&quot;. Currently each chunk
+is the same size as a NAND flash page (ie. 512 bytes + 16 byte
+spare). In the future we might decide to allow for different chunk
+sizes. Chunks can hold either:</P>
+<UL>
+       <LI><P>A yaffs_ObjectHeader. This is the way a yaffs_Object gets
+       stored on NAND.</P>
+       <LI><P>A chunk of file data.</P>
+</UL>
+<P>The 16 byte spare area contains:</P>
+<UL>
+       <LI><P>8 bytes of tags,</P>
+       <LI><P>6 bytes of ECC data</P>
+       <LI><P>1 byte block status (used to identify damaged blocks)</P>
+       <LI><P>1 byte data status (currently unused).</P>
+</UL>
+<P>The tags are made up as follows:</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>typedef
+struct</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>{</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>
+   unsigned chunkId:20;     //chunk number in file</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>
+   unsigned serialNumber:2; //serial number for chunk</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>
+   unsigned byteCount:10;   //number of bytes of data used in this
+chunk</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>
+   unsigned objectId:18;    //the object id that this chunk belongs
+to. </FONT></FONT>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>
+   unsigned ecc:12;         //ECC on tags</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>
+   unsigned unusedStuff:2;  //unused</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>}
+yaffs_Tags;</FONT></FONT></P>
+<P STYLE="margin-bottom: 0cm"><BR>
+</P>
+<P>A chunkId of zero indicates that this chunk holds a
+yaffs_ObjectHeader. A non zero value indicates that this is a data
+chunk and  the position of the chunk in the file (ie. the first chunk
+- at offset 0 - has chunkId 1). See yaffs_guts.c:yaffs_Scan () to see
+how this is done.</P>
+<P>When a chunk is repalced (eg. file details changed or a part of a
+file was overwritten), the new chunk is written before the old chunk
+is deleted. This means that we don't lose data if there is a power
+loss after the new chunk is created but before the old one is
+discarded, but it does mean that we can encounter the situation where
+we find both the old and the new chunks in flash. The serialNumber is
+incremented each time the chunk is written. 2 bits is sufficient to
+resolve any ambiguity.</P>
+<P>bytecount applies only to data chunks and tells how many of the
+data bytes are valid.</P>
+<P>objectId says which object this chunk belongs to.</P>
+<P>ecc is used to perform error correction on the tags. Another ecc
+field is used to error correct the data.</P>
+<P><BR><BR>
+</P>
+<H3>yaffs_ObjectHeader</H3>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>typedef
+struct</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>{</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  yaffs_ObjectType
+type;</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><BR>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  //
+Apply to everything    </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  int
+  parentObjectId;</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u16
+sum;   // checksum of name</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  char
+ name[YAFFS_MAX_NAME_LENGTH + 1];</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><BR>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  //
+Thes following apply to directories, files, symlinks - not hard links</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_mode;  // protection</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_uid;   // user ID of owner</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_gid;    // group ID of owner </FONT></FONT>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_atime; // time of last access</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_mtime; // time of last modification</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  __u32
+st_ctime; // time of last change</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  //
+File size  applies to files only</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  int
+fileSize; </FONT></FONT>
+</P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>          </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  //
+Equivalent object id applies to hard links only.</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  int
+ equivalentObjectId;</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>
+        // alias only applies to symlinks</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  char
+alias[YAFFS_MAX_ALIAS_LENGTH + 1];</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>  </FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><FONT FACE="Courier, monospace"><FONT SIZE=2>}
+yaffs_ObjectHeader;</FONT></FONT></P>
+<P STYLE="margin-left: 2cm; margin-bottom: 0cm"><BR>
+</P>
+<P>A yaffs_ObjectHeader is stored in NAND for every yaffs_Object.</P>
+<P>type holds the type of yaffs_Object (file,directory,hardlink or
+symlink).</P>
+<P>parentObject is the objectId of this object's parent. name holds
+the object's name. Together these form the directory structure of the
+file system. Also worth mention is sum. This is a &quot;checksum&quot;
+on the name which speeds directory searching (ie. when searching the
+directory we only compare the name for those entries where sum
+matches).</P>
+<P>Obvious stuff skipped....</P>
+<P>equivalentObjectId is used by hardlinks. A hardlink to an object
+uses this field to specify the object that this links to. This way of
+doing things is a bit different than the normal Linux way of doing
+things (ie. keeping the links distinct from the inode) but is simpler
+and uses less space except for a few corner cases with hardlinks.</P>
+<P>alias is used by symlinks to hold the symlink alias string. This
+limits the size of the symlink alias. In future we should expand
+YAFFS to use data chunks to store aliases too long to fit into the
+yaffs_ObjectHeader.</P>
+<P><BR><BR>
+</P>
+<H3>NAND Interface</H3>
+<P>All NAND access is performed via four functions pointed to by
+yaffs_Device. At the moment a chunk is a page.</P>
+<UL>
+       <LI><P><FONT FACE="Courier, monospace"><FONT SIZE=2>int
+       WriteChunkToNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND,
+       const __u8 *data, yaffs_Spare *spare)</FONT></FONT></P>
+       <LI><P><FONT FACE="Courier, monospace"><FONT SIZE=2>int
+       ReadChunkFromNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND,
+       __u8 *data, yaffs_Spare *spare);</FONT></FONT></P>
+       <LI><P><FONT FACE="Courier, monospace"><FONT SIZE=2>int
+       EraseBlockInNAND(struct yaffs_DeviceStruct *dev,int blockInNAND);</FONT></FONT></P>
+       <LI><P><FONT FACE="Courier, monospace"><FONT SIZE=2>int
+       InitialiseNAND(struct yaffs_DeviceStruct *dev);</FONT></FONT></P>
+</UL>
+<P>In the Readxxx and Writexxx functions, the data and/or spare
+pointers may be NULL in which case these data transfers are ignored.</P>
+<P>A quick note about NAND:</P>
+<UL>
+       <LI><P>NAND is not random access, but page oriented. Thus, we do all
+       reads &amp; writes in pages.</P>
+       <LI><P>Each NAND page holds 512 bytes of data and 16 &quot;spare&quot;
+       bytes. Yaffs structures the spare area with tags used to identify
+       what is stored in the data area. There are 32 such pages to a block.</P>
+       <LI><P>NAND writes will only change 1 bits to 0. eg. if a byte holds
+       10110011 and you write 11011010 to it you will get the logical and
+       of the two values: 10010010. The only way to get 1s again is to
+       erase the entire block. 
+       </P>
+       <LI><P>You may only write to a page a few times before erasing the
+       entire block. Yaffs lives within these limitations. Each page only
+       gets written to twice (once when written and once when discarded).</P>
+       <LI><P>ECC is normally used with NAND to correct for single bit
+       errors. YAFFS applies the ECC itself, so the MTD should not do this.</P>
+       <LI><P>The current mtd interfaces are not particularly well suited
+       to YAFFS and we will address the issue with the mtd group. (The mtd
+       interface does not support page-oriented read/write which YAFFS
+       would prefer).</P>
+</UL>
+<P><BR><BR>
+</P>
+<H3>mkyaffs</H3>
+<P>mkyaffs is the tool to format a NAND mtd to be used for YAFFS.
+This is quite simple, just erase all the undamaged blocks. YAFFS
+treats erased blocks as free (empty) space.</P>
+<P><BR><BR>
+</P>
+<H2>Expected performance</H2>
+<P>The following numbers should give an indication of the performance
+we should expect from YAFFS.</P>
+<P>As an example, I'll use the following numbers. Since the hardware
+is capable of 50ns read/write, these numbers allow for some other
+ovberheads. Clearly though, the performance can be degraded in
+various ways.</P>
+<TABLE WIDTH=233 BORDER=1 CELLPADDING=4 CELLSPACING=3>
+       <COL WIDTH=103>
+       <COL WIDTH=103>
+       <THEAD>
+               <TR VALIGN=TOP>
+                       <TH WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">Seek</P>
+                       </TH>
+                       <TH WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">10uS/page</P>
+                       </TH>
+               </TR>
+       </THEAD>
+       <TBODY>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">Read</P>
+                       </TD>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">100nS/byte</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">Write</P>
+                       </TD>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">100nS/byte</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">Program</P>
+                       </TD>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">200uS/page</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">Erase</P>
+                       </TD>
+                       <TD WIDTH=103>
+                               <P ALIGN=LEFT STYLE="font-style: normal">2mS/block</P>
+                       </TD>
+               </TR>
+       </TBODY>
+</TABLE>
+<P><BR><BR>
+</P>
+<P>From this we can derive some higher-level numbers:</P>
+<TABLE WIDTH=706 BORDER=1 CELLPADDING=4 CELLSPACING=3>
+       <COL WIDTH=204>
+       <COL WIDTH=160>
+       <COL WIDTH=304>
+       <THEAD>
+               <TR VALIGN=TOP>
+                       <TH WIDTH=204>
+                               <P>Operation</P>
+                       </TH>
+                       <TH WIDTH=160>
+                               <P>Time</P>
+                       </TH>
+                       <TH WIDTH=304>
+                               <P>Calculation</P>
+                       </TH>
+               </TR>
+       </THEAD>
+       <TBODY>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=204>
+                               <P>Read spare</P>
+                       </TD>
+                       <TD WIDTH=160>
+                               <P>12uS</P>
+                       </TD>
+                       <TD WIDTH=304>
+                               <P>seek + 16 * read</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=204>
+                               <P>Read page</P>
+                       </TD>
+                       <TD WIDTH=160>
+                               <P>63 uS</P>
+                       </TD>
+                       <TD WIDTH=304>
+                               <P>seek + 528 * read</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=204>
+                               <P>Write page</P>
+                       </TD>
+                       <TD WIDTH=160>
+                               <P>326 uS</P>
+                       </TD>
+                       <TD WIDTH=304>
+                               <P>seek + 528 * write + program + read page (for verification)</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=204>
+                               <P>Discard page</P>
+                       </TD>
+                       <TD WIDTH=160>
+                               <P>212 uS</P>
+                       </TD>
+                       <TD WIDTH=304>
+                               <P>seek + 16 * write + program</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=204>
+                               <P>Overwrite page</P>
+                       </TD>
+                       <TD WIDTH=160>
+                               <P>538 uS</P>
+                       </TD>
+                       <TD WIDTH=304>
+                               <P>write page + discard page</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=204>
+                               <P>Erase overhead per page</P>
+                       </TD>
+                       <TD WIDTH=160>
+                               <P>63uS</P>
+                       </TD>
+                       <TD WIDTH=304>
+                               <P>erase/32</P>
+                       </TD>
+               </TR>
+       </TBODY>
+</TABLE>
+<P><BR><BR>
+</P>
+<P>From this we can infer the following flash access times:</P>
+<TABLE WIDTH=704 BORDER=1 CELLPADDING=4 CELLSPACING=3>
+       <COL WIDTH=196>
+       <COL WIDTH=167>
+       <COL WIDTH=303>
+       <THEAD>
+               <TR VALIGN=TOP>
+                       <TH WIDTH=196>
+                               <P>Operation</P>
+                       </TH>
+                       <TH WIDTH=167>
+                               <P>Time</P>
+                       </TH>
+                       <TH WIDTH=303>
+                               <P>Calculation</P>
+                       </TH>
+               </TR>
+       </THEAD>
+       <TBODY>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=196>
+                               <P>Read 1MB file</P>
+                       </TD>
+                       <TD WIDTH=167>
+                               <P>0.13s (about 7.5 MB/s)</P>
+                       </TD>
+                       <TD WIDTH=303>
+                               <P>2000 * read page</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=196>
+                               <P>Write 1MB (clean system)</P>
+                       </TD>
+                       <TD WIDTH=167>
+                               <P>0.53s (about 1.8 MB/s)</P>
+                       </TD>
+                       <TD WIDTH=303>
+                               <P>2000 * write page</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=196>
+                               <P>Overwrite 1MB file (no gc)</P>
+                       </TD>
+                       <TD WIDTH=167>
+                               <P>1.08s (about 0.9MB/s)</P>
+                       </TD>
+                       <TD WIDTH=303>
+                               <P>2000 * overwrite page</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=196>
+                               <P>Overwrite 1MB with 50% gc</P>
+                       </TD>
+                       <TD WIDTH=167>
+                               <P>2.4s (about 0.4 MB/s)</P>
+                       </TD>
+                       <TD WIDTH=303>
+                               <P>2000 * overwrite page + 2000 * page copy (== overwrite page) +
+                               4000 * erase overhead</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=196>
+                               <P>Delete 1MB file</P>
+                       </TD>
+                       <TD WIDTH=167>
+                               <P>0.43s (about 2.2 MB/s)</P>
+                       </TD>
+                       <TD WIDTH=303>
+                               <P>2000 * discard page</P>
+                       </TD>
+               </TR>
+               <TR VALIGN=TOP>
+                       <TD WIDTH=196>
+                               <P>Delete 1MB file with 50% gc</P>
+                       </TD>
+                       <TD WIDTH=167>
+                               <P>0.49s (about 2.0MB/s)</P>
+                       </TD>
+                       <TD WIDTH=303>
+                               <P>2000 * discard page + 1000 * erase overhead</P>
+                       </TD>
+               </TR>
+       </TBODY>
+</TABLE>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+</BODY>
+</HTML>
\ No newline at end of file
diff --git a/Documentation/yaffs_report20020211.html b/Documentation/yaffs_report20020211.html
new file mode 100644 (file)
index 0000000..212eb88
--- /dev/null
@@ -0,0 +1,81 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
+<HTML>
+<HEAD>
+       <META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=iso-8859-1">
+       <TITLE></TITLE>
+       <META NAME="GENERATOR" CONTENT="StarOffice/5.2 (Linux)">
+       <META NAME="AUTHOR" CONTENT=" ">
+       <META NAME="CREATED" CONTENT="20020211;20201700">
+       <META NAME="CHANGEDBY" CONTENT=" ">
+       <META NAME="CHANGED" CONTENT="20020211;21005100">
+</HEAD>
+<BODY>
+<H3>YAFFS Progress 11 Feb 2002</H3>
+<H3>Approach</H3>
+<P><I>C. A. R. Hoare, in his 1980 ACM Turing Award lecture, told of
+two ways of constructing a software design: &quot;One way is to make
+it so simple that there are obviously no deficiencies and the other
+way is to make it so complicated that there are no obvious
+deficiencies.&quot;</I></P>
+<P>The approach I'm taking with Yaffs is to design and make notes up
+front as much as possible. I find this helps make the coding/debug
+phase go way faster and more predictably.</P>
+<P>Although obviously the code ends up in the kernel, I'm abstracting
+out kernel services so that I develop/debug in user space using
+vanilla dev tools. I like to use Source Navigator because it has a
+nice xref capability though a few quirks too). Thus, yaffs code will
+be tested in application space wrapped in a test harness which calls
+the yaffs functions. and sits on top of a NAND emulation layer (just
+two big disk files).  I can then do things like force ecc failures
+etc at will to test recovery logic and check booting etc. This
+general approach has served me well in the past and I expect it will
+this time too.</P>
+<H3>Design</H3>
+<P>At this stage all the major design work is done. Basically there
+are 3 in RAM management &quot;objects&quot;:</P>
+<UL>
+       <LI><P> inodes: An inode maps to the normal file system concept of
+       an inode. It is thus either a file or a directory. <BR>A file type
+       inode points to a tnode tree which is a layered tree that is used to
+       quickly find the pages of data in NAND.<BR>A directory type inode
+       has a list of children links (ie. the links in that directory).<BR>An
+       inode knows which hard links are associated with it.<BR>inode
+       look-up uses a hashing table.</P>
+       <LI><P>links: Links are hard or soft links. All links have a parent
+       inode (ie. the directory they're in). <BR>Hard links point to an
+       inode.<BR>Soft links are just alias strings.<BR>Instead of storing
+       the link name in RAM (big and wasteful and variable size), the
+       location in NAND is stored instead and a u16 &quot;checksum&quot;
+       value is stored in RAM to help in quickly scanning links [ie. say
+       the checksum for &quot;freddies_file&quot; is 123 then when I go
+       search for it I don't need to go look at every link in NAND (slow),
+       just those that match checksum 123]. 
+       </P>
+       <LI><P>tnodes: Tnodes are a tiered tree system to rapidly get from
+       inodes to their data pages in RAM.</P>
+</UL>
+<P>There is a need for speed in certain areas, such as rapidly
+locating inodes, links data pages during certain scenarios (eg.
+garbage collection). These have been identified and suitable  look-up
+structures are in place.</P>
+<P>All dynamic data structures are allocated from pools rather than
+one at a time. This is more efficient time-wise and simplifies
+clean-up.</P>
+<H3>Code</H3>
+<P>Much of the code for the management layers is already in place, as
+is some of the tag management code. Some of the code has already been
+tested.</P>
+<P>I have started with coding the management layer since this is the
+most critical part to get right. Every now and then I have coded up
+some other section to verify that what I have will work.</P>
+<H3>Time</H3>
+<P>So far I've logged 65 hours on yaffs (though it chews up
+significant null cycles too :-)). I believe this is comfortably
+within budget. I was not able to make much progress through Christmas
+and the week of January, but am able to give a lot more effort now.</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+</BODY>
+</HTML>
\ No newline at end of file
diff --git a/Documentation/yaffs_report20020304.html b/Documentation/yaffs_report20020304.html
new file mode 100644 (file)
index 0000000..afc7569
--- /dev/null
@@ -0,0 +1,57 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
+<HTML>
+<HEAD>
+       <META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=iso-8859-1">
+       <TITLE></TITLE>
+       <META NAME="GENERATOR" CONTENT="StarOffice/5.2 (Linux)">
+       <META NAME="AUTHOR" CONTENT=" ">
+       <META NAME="CREATED" CONTENT="20020211;20201700">
+       <META NAME="CHANGEDBY" CONTENT=" ">
+       <META NAME="CHANGED" CONTENT="20020304;21123700">
+</HEAD>
+<BODY>
+<H3>YAFFS Progress 4 March 2002</H3>
+<H3><BR><BR>
+</H3>
+<H3>Design</H3>
+<P>A few of the design areas needed to be tweaked slightly without
+significant impact.</P>
+<P>The only real significance is that what is termed a yaffs_Inode
+really becomes an object Id. Where an 'object' is a file, directory,
+symlink or hard link. This differs from the *nix concept of an inode
+in that a hard link is not an inode. yaffs_Inode should really be
+renamed to yaffs_Object to reflect this.</P>
+<P>Rge reason for introducing the object is to provide identifiers
+for the objects stored on NAND. For example, each hardlink (which
+does not have a distinct inode) needs an object Id for storage on 
+</P>
+<H3>Code</H3>
+<P>Pretty much all the guts of the code is there except for:</P>
+<UL>
+       <LI><P>symlink handling (a doddle)</P>
+       <LI><P>hard link handling.</P>
+       <LI><P>some of start-up scanning</P>
+       <LI><P>ECC on tags</P>
+       <LI><P>superblock handling (ie hook-up to mtd and the Linux VFS).
+       Some of this code to be pinched from JFFS2.</P>
+</UL>
+<P>Some of the code has already been tested.</P>
+<P>I will now be testing out the guts on a NAND emulation layer in an
+application. This provides better debugging. I hope to have this
+running by 11/03/2002. 
+</P>
+<P>Once the guts looks solid on the NAND emulation, I will graft it
+on to the VFS and mtd -  at which point it becomes a real file
+system.</P>
+<H3>Time</H3>
+<P>So far I've logged 90 hours on yaffs. I will not be charging for
+approx 15 hours I have spent swotting up on the Linux VFS. I still
+believe this is on budget.</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+<P><BR><BR>
+</P>
+</BODY>
+</HTML>
\ No newline at end of file
diff --git a/Makefile b/Makefile
new file mode 100644 (file)
index 0000000..a0d8138
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,38 @@
+#Makefile for YAFFS as a module
+#
+# NB this is not yet suitable for putting into the kernel tree.
+# YAFFS: Yet another FFS. A NAND-flash specific file system. 
+#
+# Copyright (C) 2002 Aleph One Ltd.
+#   for Toby Churchill Ltd and Brightstar Engineering
+#
+# Created by Charles Manning <charles@aleph1.co.uk>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+
+## Change or override  KERNELDIR to your kernel
+## comment out USE_xxxx if you don't want these features.
+
+KERNELDIR = /usr/src/kernel-headers-2.4.18
+USE_RAM_FOR_TEST = -DYAFFS_RAM_ENABLED
+USE_MTD = -DYAFFS_MTD_ENABLED
+
+
+CFLAGS = -D__KERNEL__ -DMODULE $(USE_RAM_FOR_TEST) $(USE_MTD)  -I$(KERNELDIR)/include -O2 -Wall
+
+
+OBJS = yaffs_fs.o yaffs_guts.o yaffs_ramem.o yaffs_mtdif.o
+
+
+all: yaffs.o
+
+$(OBJS): %.o: %.c
+       gcc -c $(CFLAGS) $< -o $@
+
+yaffs.o: $(OBJS)
+       ld -r $(OBJS) -o $@
+
+clean:
+       rm -f $(OBJS) core
diff --git a/devextras.h b/devextras.h
new file mode 100644 (file)
index 0000000..a28135f
--- /dev/null
@@ -0,0 +1,257 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * devextras.h
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This file is just holds extra declarations used during development.
+ * Most of these are from kernel includes placed here so we can use them in 
+ * applications.
+ *
+ */
+#ifndef __EXTRAS_H__
+#define __EXTRAS_H__
+
+#ifndef __KERNEL__
+
+// User space defines
+
+typedef unsigned char   __u8;
+typedef unsigned short  __u16;
+typedef unsigned        __u32;
+
+
+/*
+ * Simple doubly linked list implementation.
+ *
+ * Some of the internal functions ("__xxx") are useful when
+ * manipulating whole lists rather than single entries, as
+ * sometimes we already know the next/prev entries and we can
+ * generate better code by using them directly rather than
+ * using the generic single-entry routines.
+ */
+ #define prefetch(x) 1
+
+struct list_head {
+       struct list_head *next, *prev;
+};
+
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
+
+#define LIST_HEAD(name) \
+       struct list_head name = LIST_HEAD_INIT(name)
+
+#define INIT_LIST_HEAD(ptr) do { \
+       (ptr)->next = (ptr); (ptr)->prev = (ptr); \
+} while (0)
+
+/*
+ * Insert a new entry between two known consecutive entries.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static __inline__ void __list_add(struct list_head * new,
+       struct list_head * prev,
+       struct list_head * next)
+{
+       next->prev = new;
+       new->next = next;
+       new->prev = prev;
+       prev->next = new;
+}
+
+/**
+ * list_add - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it after
+ *
+ * Insert a new entry after the specified head.
+ * This is good for implementing stacks.
+ */
+static __inline__ void list_add(struct list_head *new, struct list_head *head)
+{
+       __list_add(new, head, head->next);
+}
+
+/**
+ * list_add_tail - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it before
+ *
+ * Insert a new entry before the specified head.
+ * This is useful for implementing queues.
+ */
+static __inline__ void list_add_tail(struct list_head *new, struct list_head *head)
+{
+       __list_add(new, head->prev, head);
+}
+
+/*
+ * Delete a list entry by making the prev/next entries
+ * point to each other.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static __inline__ void __list_del(struct list_head * prev,
+                                 struct list_head * next)
+{
+       next->prev = prev;
+       prev->next = next;
+}
+
+/**
+ * list_del - deletes entry from list.
+ * @entry: the element to delete from the list.
+ * Note: list_empty on entry does not return true after this, the entry is in an undefined state.
+ */
+static __inline__ void list_del(struct list_head *entry)
+{
+       __list_del(entry->prev, entry->next);
+}
+
+/**
+ * list_del_init - deletes entry from list and reinitialize it.
+ * @entry: the element to delete from the list.
+ */
+static __inline__ void list_del_init(struct list_head *entry)
+{
+       __list_del(entry->prev, entry->next);
+       INIT_LIST_HEAD(entry);
+}
+
+/**
+ * list_empty - tests whether a list is empty
+ * @head: the list to test.
+ */
+static __inline__ int list_empty(struct list_head *head)
+{
+       return head->next == head;
+}
+
+/**
+ * list_splice - join two lists
+ * @list: the new list to add.
+ * @head: the place to add it in the first list.
+ */
+static __inline__ void list_splice(struct list_head *list, struct list_head *head)
+{
+       struct list_head *first = list->next;
+
+       if (first != list) {
+               struct list_head *last = list->prev;
+               struct list_head *at = head->next;
+
+               first->prev = head;
+               head->next = first;
+
+               last->next = at;
+               at->prev = last;
+       }
+}
+
+/**
+ * list_entry - get the struct for this entry
+ * @ptr:       the &struct list_head pointer.
+ * @type:      the type of the struct this is embedded in.
+ * @member:    the name of the list_struct within the struct.
+ */
+#define list_entry(ptr, type, member) \
+       ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
+
+/**
+ * list_for_each       -       iterate over a list
+ * @pos:       the &struct list_head to use as a loop counter.
+ * @head:      the head for your list.
+ */
+#define list_for_each(pos, head) \
+       for (pos = (head)->next, prefetch(pos->next); pos != (head); \
+               pos = pos->next, prefetch(pos->next))
+
+/**
+ * list_for_each_safe  -       iterate over a list safe against removal of list entry
+ * @pos:       the &struct list_head to use as a loop counter.
+ * @n:         another &struct list_head to use as temporary storage
+ * @head:      the head for your list.
+ */
+#define list_for_each_safe(pos, n, head) \
+       for (pos = (head)->next, n = pos->next; pos != (head); \
+               pos = n, n = pos->next)
+
+
+
+#define CURRENT_TIME 0
+
+
+/*
+ * File types
+ */
+#define DT_UNKNOWN     0
+#define DT_FIFO                1
+#define DT_CHR         2
+#define DT_DIR         4
+#define DT_BLK         6
+#define DT_REG         8
+#define DT_LNK         10
+#define DT_SOCK                12
+#define DT_WHT         14
+
+#include <sys/stat.h>
+
+/*
+ * Attribute flags.  These should be or-ed together to figure out what
+ * has been changed!
+ */
+#define ATTR_MODE      1
+#define ATTR_UID       2
+#define ATTR_GID       4
+#define ATTR_SIZE      8
+#define ATTR_ATIME     16
+#define ATTR_MTIME     32
+#define ATTR_CTIME     64
+#define ATTR_ATIME_SET 128
+#define ATTR_MTIME_SET 256
+#define ATTR_FORCE     512     /* Not a change, but a change it */
+#define ATTR_ATTR_FLAG 1024
+
+
+struct iattr {
+       unsigned int    ia_valid;
+       unsigned                ia_mode;
+       unsigned                ia_uid;
+       unsigned                ia_gid;
+       unsigned                ia_size;
+       unsigned                ia_atime;
+       unsigned        ia_mtime;
+       unsigned        ia_ctime;
+       unsigned int    ia_attr_flags;
+};
+
+#define KERN_DEBUG
+
+
+#else
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/stat.h>
+
+
+#endif
+
+
+
+
+#endif
+
diff --git a/snMakefile b/snMakefile
new file mode 100644 (file)
index 0000000..4557fa5
--- /dev/null
@@ -0,0 +1,79 @@
+#########################################################
+# Makefile auto generated by Cygnus Source Navigator.
+# Target: yaffsdev_RAM Date: May 03 2002 Time: 07:11:35 PM
+#
+
+
+.SUFFIXES: .cc .class .java .cxx .C .cpp .o .c .l .y
+
+
+VPATH = /opt/aleph1/yaffs/.
+
+
+YACC = bison
+LEX = flex
+JAVA = gcj
+CC = gcc
+CPP = g++
+YACC_FLAGS =      
+LEX_FLAGS =      
+JAVA_FLAGS =      
+CC_FLAGS =  -g  -Wall  
+CPP_FLAGS =      
+YACC_INCLUDES = 
+LEX_INCLUDES = 
+JAVA_INCLUDES = 
+CC_INCLUDES = 
+CPP_INCLUDES = 
+YACC_DEFINES = 
+LEX_DEFINES = 
+JAVA_DEFINES = 
+CC_DEFINES = 
+CPP_DEFINES = 
+yaffsdev_RAM_LIBS = 
+LINKER = gcc
+LINKER_FLAGS = 
+LINKER_ENTRY = 
+yaffsdev_RAM_OBJECTS = yaffs_guts.o yaffs_ramem.o yaffsdev.o
+
+all: yaffsdev
+
+yaffsdev: $(yaffsdev_RAM_OBJECTS)
+       $(LINKER) -o yaffsdev $(LINKER_ENTRY) $(LINKER_FLAGS) $(yaffsdev_RAM_OBJECTS) $(yaffsdev_RAM_LIBS)
+
+.y.c:
+       $(YACC) $< $(YACC_FLAGS) $(YACC_DEFINES) $(YACC_INCLUDES)
+
+
+.l.c:
+       $(LEX) -t $< > $@ $(LEX_FLAGS) $(LEX_DEFINES) $(LEX_INCLUDES)
+
+
+.java.o:
+       $(JAVA) -c $< $(JAVA_FLAGS) $(JAVA_DEFINES) $(JAVA_INCLUDES)
+.class:
+       $(JAVA) -c $< $(JAVA_FLAGS) $(JAVA_DEFINES) $(JAVA_INCLUDES)
+
+
+.c.o:
+       $(CC) -c $< $(CC_FLAGS) $(CC_DEFINES) $(CC_INCLUDES)
+
+
+.cpp.o:
+       $(CPP) -c $< $(CPP_FLAGS) $(CPP_DEFINES) $(CPP_INCLUDES)
+.C.o:
+       $(CPP) -c $< $(CPP_FLAGS) $(CPP_DEFINES) $(CPP_INCLUDES)
+.cc.o:
+       $(CPP) -c $< $(CPP_FLAGS) $(CPP_DEFINES) $(CPP_INCLUDES)
+.cxx.o:
+       $(CPP) -c $< $(CPP_FLAGS) $(CPP_DEFINES) $(CPP_INCLUDES)
+
+
+yaffs_guts.o: /opt/aleph1/yaffs/yaffs_guts.h /opt/aleph1/yaffs/yaffsinterface.h /opt/aleph1/yaffs/yportenv.h
+yaffs_ramem.o: yaffs_nandemul.h /opt/aleph1/yaffs/devextras.h /opt/aleph1/yaffs/yaffs_guts.h /opt/aleph1/yaffs/yaffsinterface.h /opt/aleph1/yaffs/yportenv.h
+yaffsdev.o: yaffs_nandemul.h /usr/include/stdio.h /usr/include/stdlib.h /usr/include/string.h /opt/aleph1/yaffs/yaffs_guts.h /opt/aleph1/yaffs/yaffsinterface.h
+
+clean:
+       rm -f *.o
+       rm -f yaffsdev
+
diff --git a/utils/Makefile b/utils/Makefile
new file mode 100644 (file)
index 0000000..fdc64a3
--- /dev/null
@@ -0,0 +1,34 @@
+#Makefile for mkyaffs
+#
+# NB this is not yet suitable for putting into the kernel tree.
+# YAFFS: Yet another FFS. A NAND-flash specific file system. 
+#
+# Copyright (C) 2002 Aleph One Ltd.
+#   for Toby Churchill Ltd and Brightstar Engineering
+#
+# Created by Charles Manning <charles@aleph1.co.uk>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+
+## Change or override  KERNELDIR to your kernel
+
+KERNELDIR = /usr/src/kernel-headers-2.4.18
+
+CFLAGS =   -I$(KERNELDIR)/include -O2 -Wall
+
+
+OBJS = mkyaffs.o
+
+
+all: mkyaffs
+
+$(OBJS): %.o: %.c
+       gcc -c $(CFLAGS) $< -o $@
+
+mkyaffs: $(OBJS)
+       gcc -o $@ $(OBJS)
+
+clean:
+       rm -f $(OBJS) core
diff --git a/utils/mkyaffs b/utils/mkyaffs
new file mode 100755 (executable)
index 0000000..27e3a08
Binary files /dev/null and b/utils/mkyaffs differ
diff --git a/utils/mkyaffs.c b/utils/mkyaffs.c
new file mode 100644 (file)
index 0000000..7fd2b0b
--- /dev/null
@@ -0,0 +1,150 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * mkyaffs.c Format a chunk of NAND for YAFFS.
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  Acknowledgement:
+ *  This file is crafted from nandtest.c by  Miguel Freitas (miguel@cetuc.puc-rio.br)
+ *  and Steven J. Hill (sjhill@cotw.com)
+ *
+ * Overview:
+ * Formatting a YAFFS device is very simple. Just erase all undamaged blocks. 
+ * NB Don't erase blocks maked as damaged.
+ */
+
+#define _GNU_SOURCE
+#include <ctype.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <asm/types.h>
+#include <linux/config.h>
+#include <linux/mtd/mtd.h>
+
+
+// countBits is a quick way of counting the number of bits in a byte.
+// ie. countBits[n] holds the number of 1 bits in a byte with the value n.
+
+static const char countBits[256] =
+{
+0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8
+};
+
+/*
+ * Buffer arrays used for running tests
+ */
+
+unsigned char oobbuf[16];
+
+
+/*
+ * Main program
+ */
+int main(int argc, char **argv)
+{
+       unsigned long addr;
+       int bs, fd, i;
+       struct mtd_oob_buf oob = {0, 16, (unsigned char *) &oobbuf};
+       mtd_info_t meminfo;
+       erase_info_t erase;
+
+       /* Make sure a device was specified */
+       if(argc < 2) {
+               printf("usage: %s <mtdname>\n", argv[0]);
+               exit(1);
+       }
+
+       /* Open the device */
+       if((fd = open(argv[1], O_RDWR)) == -1) {
+               perror("open flash");
+               exit(1);
+       }
+
+       /* Fill in MTD device capability structure */
+       if(ioctl(fd, MEMGETINFO, &meminfo) != 0) {
+               perror("MEMGETINFO");
+               close(fd);
+               exit(1);
+       }
+
+       /* Make sure device page sizes are valid */
+       if( !(meminfo.oobsize == 16 && meminfo.oobblock == 512)) 
+       {
+               printf("Unknown flash (not normal NAND)\n");
+               close(fd);
+               exit(1);
+       }
+       
+       
+       for(addr = 0; addr < meminfo.size; addr += meminfo.erasesize)
+       {
+               /* Read the OOB data to determine if the block is valid.
+                * If the block is damaged, then byte 5 of the OOB data will
+                * have at least 2 zero bits.
+                */
+               oob.start = addr;
+               oob.length = 16;
+               oob.ptr = oobbuf;
+               if (ioctl(fd, MEMREADOOB, &oob) != 0) 
+               {
+                       perror("ioctl(MEMREADOOB)");
+                       close(fd);
+                       exit(1);
+               }
+               
+               if(countBits[oobbuf[5]] < 7)
+               {
+                       printf("Block at 0x08%lx is damaged and is not being formatted\n",addr);
+               }
+               else
+               {
+                       /* Erase this block */
+                       erase.start = addr;
+                       erase.length = meminfo.erasesize;
+                       printf("Erasing block at 0x08%lx\n",addr);
+                       if(ioctl(fd, MEMERASE, &erase) != 0) 
+                       {
+                               perror("\nMTD Erase failure\n");
+                               close(fd);
+                               exit(1);
+                       }
+                       
+               }
+
+       }
+
+
+       /* All the tests succeeded */
+       printf("OK\n");
+       close(fd);
+       return 0;
+}
+
diff --git a/yaffs-header.c b/yaffs-header.c
new file mode 100644 (file)
index 0000000..7cb71e0
--- /dev/null
@@ -0,0 +1,13 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
diff --git a/yaffs_fileem.c b/yaffs_fileem.c
new file mode 100644 (file)
index 0000000..a137fb4
--- /dev/null
@@ -0,0 +1,145 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * yaffs_fileem.c  NAND emulation on top of files
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+ //yaffs_fileem.c
+
+#include "yaffs_nandif.h"
+#include "yaffs_guts.h"
+#include "yaffsinterface.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+
+#define FILE_SIZE_IN_MEG 2
+
+#define BLOCK_SIZE (32 * 528)
+#define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
+#define FILE_SIZE_IN_BLOCKS (FILE_SIZE_IN_MEG * BLOCKS_PER_MEG)
+#define FILE_SIZE_IN_BYTES (FILE_SIZE_IN_BLOCKS * BLOCK_SIZE)
+
+
+static int h;
+static __u8 ffChunk[528];
+
+
+
+static void  CheckInit(void)
+{
+       static int initialised = 0;
+
+       int length;
+
+       
+       if(!initialised)
+       {
+               memset(ffChunk,0xFF,528);
+               
+               h = open("yaffs-em-file" , O_RDWR | O_CREAT, S_IREAD | S_IWRITE);
+               if(h < 0)
+               {
+                       perror("Fatal error opening yaffs emulation file");
+                       exit(1);
+               }
+               initialised = 1;
+               
+               length = lseek(h,0,SEEK_END);
+               if(length !=  FILE_SIZE_IN_BYTES)
+               {
+                       // Create file contents
+                       int i;
+                       
+                       printf("Creating emulation file...\n");
+                       for(i = 0; i < FILE_SIZE_IN_BLOCKS; i++)
+                       {
+                               yaffs_EraseBlockInNAND(i);
+                       }
+               }
+       }
+}
+
+int yaffs_WriteChunkToNAND(int chunkInNAND,__u8 *data, yaffs_Spare *spare)
+{
+       int pos;
+       
+       pos = chunkInNAND * 528;
+       
+       CheckInit();
+       
+       
+       if(data)
+       {
+               lseek(h,pos,SEEK_SET);
+               write(h,data,512);
+       }
+       
+       pos += 512;
+       
+       if(spare)
+       {
+               lseek(h,pos,SEEK_SET);
+               write(h,spare,16);      
+       }
+
+       return YAFFS_OK;
+}
+
+
+int yaffs_ReadChunkFromNAND(int chunkInNAND, __u8 *data, yaffs_Spare *spare)
+{
+       int pos;
+
+       pos = chunkInNAND * 528;
+       
+       
+       CheckInit();
+       
+       if(data)
+       {
+               lseek(h,pos,SEEK_SET);
+               read(h,data,512);
+       }
+       
+       pos += 512;
+       
+       if(spare)
+       {
+               lseek(h,pos,SEEK_SET);
+               read(h,spare,16);       
+       }
+
+       return YAFFS_OK;
+}
+
+
+int yaffs_EraseBlockInNAND(int blockInNAND)
+{
+       int i;
+       
+       CheckInit();
+       
+       printf("Erasing block %d\n",blockInNAND);
+       
+       lseek(h,blockInNAND * BLOCK_SIZE,SEEK_SET);
+       for(i = 0; i < 32; i++)
+       {
+               write(h,ffChunk,528);
+       }
+       return YAFFS_OK;
+}
+
diff --git a/yaffs_fs.c b/yaffs_fs.c
new file mode 100644 (file)
index 0000000..a0ada39
--- /dev/null
@@ -0,0 +1,879 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system.
+ * yaffs_fs.c
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This is the file system front-end to YAFFS that hooks it up to
+ * the VFS.
+ *
+ * Special notes:
+ * >> sb->u.generic_sbp points to the yaffs_Device associated with this superblock
+ * >> inode->u.generic_ip points to the associated yaffs_Object.
+ */
+
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/pagemap.h>
+#include <linux/mtd/mtd.h>
+#include <linux/interrupt.h>
+#include <linux/string.h>
+#include <linux/locks.h>
+
+#include <asm/uaccess.h>
+
+#include "yaffs_guts.h"
+
+#ifdef YAFFS_RAM_ENABLED
+#include "yaffs_nandemul.h"
+// 2 MB of RAM for emulation
+#define YAFFS_RAM_EMULATION_SIZE  0x200000
+#endif // YAFFS_RAM_ENABLED
+
+#ifdef YAFFS_MTD_ENABLED
+#include <linux/mtd/mtd.h>
+#include "yaffs_mtdif.h"
+#endif //YAFFS_MTD_ENABLED
+
+#define T(x) printk x
+
+
+
+#define yaffs_InodeToObject(iptr) ((yaffs_Object *)((iptr)->u.generic_ip))
+#define yaffs_DentryToObject(dptr) yaffs_InodeToObject((dptr)->d_inode)
+#define yaffs_SuperToDevice(sb)        ((yaffs_Device *)sb->u.generic_sbp)
+
+
+
+static ssize_t yaffs_file_read(struct file *f, char *buf, size_t n, loff_t *pos);
+static ssize_t yaffs_file_write(struct file *f, const char *buf, size_t n, loff_t *pos);
+
+static int yaffs_sync_object(struct file * file, struct dentry *dentry, int datasync);
+
+static int yaffs_readdir(struct file *f, void *dirent, filldir_t filldir);
+
+static int yaffs_create(struct inode *dir, struct dentry *dentry, int mode);
+static struct dentry * yaffs_lookup(struct inode *dir, struct dentry *dentry);
+static int yaffs_link(struct dentry *old_dentry, struct inode * dir, struct dentry * dentry);
+static int yaffs_unlink(struct inode * dir, struct dentry *dentry);
+static int yaffs_symlink(struct inode * dir, struct dentry *dentry, const char * symname);
+static int yaffs_mkdir(struct inode * dir, struct dentry * dentry, int mode);
+static int yaffs_mknod(struct inode *dir, struct dentry *dentry, int mode, int dev);
+static int yaffs_rename(struct inode * old_dir, struct dentry *old_dentry, struct inode * new_dir,struct dentry *new_dentry);
+static int yaffs_setattr(struct dentry *dentry, struct iattr *attr);
+
+static int yaffs_statfs(struct super_block *sb, struct statfs *buf);
+static void yaffs_read_inode (struct inode *inode);
+static struct super_block *yaffs_read_super(struct super_block * sb, void * data, int silent);
+static void yaffs_put_inode (struct inode *inode);
+
+//static int yaffs_readpage(struct file*,struct page *
+
+static struct address_space_operations yaffs_address_ops = {
+//     readpage:               yaffs_readpage,
+//     prepare_write:  yaffs_prepare_write,
+//     commit_write:   yaffs_commit_write
+};
+
+
+static struct file_operations yaffs_file_operations = {
+       read:           yaffs_file_read,
+       write:          yaffs_file_write,
+//     mmap:           generic_file_mmap,
+       fsync:          yaffs_sync_object,
+};
+
+
+static struct inode_operations yaffs_file_inode_operations = {
+       setattr:        yaffs_setattr,
+};
+
+
+
+static struct file_operations yaffs_dir_operations = {
+       read:           generic_read_dir,
+       readdir:        yaffs_readdir,
+       fsync:          yaffs_sync_object,
+};
+
+static struct inode_operations yaffs_dir_inode_operations = {
+       create:         yaffs_create,
+       lookup:         yaffs_lookup,
+       link:           yaffs_link,
+       unlink:         yaffs_unlink,
+       symlink:        yaffs_symlink,
+       mkdir:          yaffs_mkdir,
+       rmdir:          yaffs_unlink,
+       mknod:          yaffs_mknod,
+       rename:         yaffs_rename,
+       setattr:        yaffs_setattr,
+};
+
+static struct super_operations yaffs_super_ops = {
+       statfs:                 yaffs_statfs,
+       read_inode:             yaffs_read_inode,
+       put_inode:              yaffs_put_inode,
+//     read_inode:
+//     remount_fs:
+//     clear_inode:
+};
+
+
+struct inode *yaffs_get_inode(struct super_block *sb, int mode, int dev,yaffs_Object *obj);
+
+/*
+ * Lookup is used to find objects in the fs
+ */
+static struct dentry * yaffs_lookup(struct inode *dir, struct dentry *dentry)
+{
+       yaffs_Object *obj;
+       struct inode *inode;
+
+
+       T((KERN_DEBUG"yaffs_lookup for %d:%s\n",yaffs_InodeToObject(dir)->objectId,dentry->d_name.name));
+
+       obj = yaffs_FindObjectByName(yaffs_InodeToObject(dir),dentry->d_name.name);
+
+       if(obj)
+       {
+               T((KERN_DEBUG"yaffs_lookup found %d\n",obj->objectId));
+
+               inode = yaffs_get_inode(dir->i_sb, obj->st_mode,0,obj);
+
+               if(inode)
+               {
+                       T((KERN_DEBUG"yaffs_loookup looks good\n"));
+                       dget(dentry); // try to solve directory bug
+                       d_add(dentry,inode);
+                       return dentry;
+               }
+
+       }
+       else
+       {
+               T((KERN_DEBUG"yaffs_lookup not found\n"));
+
+       }
+       return NULL;
+
+}
+
+// For now put inode is just for debugging
+static void yaffs_put_inode(struct inode *inode)
+{
+       T(("yaffs_put_inode: ino %d, count %d\n",(int)inode->i_ino, atomic_read(&inode->i_count)));
+}
+
+#ifdef YAFFS_ADDRESS_OPS
+static int yaffs_readpage(struct file *file, struct page * page)
+{
+       T((KERN_DEBUG"yaffs_readpage\n"));
+
+       // TODO
+       return 0;
+}
+
+static int yaffs_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
+{
+       T((KERN_DEBUG"yaffs_prepare_write\n"));
+
+       //TODO
+       return 0;
+}
+
+static int yaffs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
+{
+
+       struct inode *inode = page->mapping->host;
+       loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+
+       T((KERN_DEBUG"yaffs_commit_write\n"));
+
+       return 0;
+}
+
+#endif //YAFFS_ADDRESS_OPS
+
+
+static void yaffs_FillInodeFromObject(struct inode *inode, yaffs_Object *obj)
+{
+       if (inode && obj)
+       {
+               inode->i_ino = obj->objectId;
+               inode->i_mode = obj->st_mode;
+               inode->i_uid = obj->st_uid;
+               inode->i_gid = obj->st_gid;
+               inode->i_blksize = YAFFS_BYTES_PER_CHUNK;
+               inode->i_blocks = 0;
+               inode->i_rdev = NODEV;
+               inode->i_mapping->a_ops = &yaffs_address_ops;
+               inode->i_atime = obj->st_atime;
+               inode->i_mtime = obj->st_mtime;
+               inode->i_ctime = obj->st_ctime;
+               inode->i_size = yaffs_GetObjectFileLength(obj);
+               inode->i_nlink = yaffs_GetObjectLinkCount(obj);
+
+               T((KERN_DEBUG"yaffs_FillInode mode %x uid %d gid %d size %d count %d\n",
+                               inode->i_mode, inode->i_uid, inode->i_gid, (int)inode->i_size, atomic_read(&inode->i_count)));
+
+               switch (obj->st_mode & S_IFMT)
+               {
+                       default:
+                       //      init_special_inode(inode, mode, dev);
+                               break;
+                       case S_IFREG:   // file
+                               inode->i_op = &yaffs_file_inode_operations;
+                               inode->i_fop = &yaffs_file_operations;
+                               break;
+                       case S_IFDIR:   // directory
+                               inode->i_op = &yaffs_dir_inode_operations;
+                               inode->i_fop = &yaffs_dir_operations;
+                               break;
+                       case S_IFLNK:   // symlink
+                               inode->i_op = &page_symlink_inode_operations;
+                               break;
+               }
+
+
+               inode->u.generic_ip = obj;
+
+       }
+       else
+       {
+               T((KERN_DEBUG"yaffs_FileInode invalid parameters\n"));
+       }
+
+}
+
+struct inode *yaffs_get_inode(struct super_block *sb, int mode, int dev,yaffs_Object *obj)
+{
+       struct inode * inode;
+
+       T((KERN_DEBUG"yaffs_get_inode for object %d\n",obj->objectId));
+
+       inode = iget(sb,obj->objectId);
+
+       // No need to call this since iget calls it via the read_inode callback
+       // yaffs_FillInodeFromObject(inode,obj);
+
+       return inode;
+}
+
+static ssize_t yaffs_file_read(struct file *f, char *buf, size_t n, loff_t *pos)
+{
+       yaffs_Object *obj;
+       int nRead,ipos;
+       struct inode *inode;
+
+       T((KERN_DEBUG"yaffs_file_read\n"));
+
+       obj  = yaffs_DentryToObject(f->f_dentry);
+       inode = f->f_dentry->d_inode;
+
+       if (*pos < inode->i_size)
+       {
+                       if (*pos + n > inode->i_size)
+                       {
+                               n = inode->i_size - *pos;
+                       }
+       }
+       else
+       {
+               n = 0;
+       }
+
+       nRead = yaffs_ReadDataFromFile(obj,buf,*pos,n);
+       if(nRead > 0)
+       {
+               f->f_pos += nRead;
+       }
+       ipos = *pos;
+       T((KERN_DEBUG"yaffs_file_read read %d bytes, %d read at %d\n",n,nRead,ipos));
+       return nRead;
+
+}
+
+static ssize_t yaffs_file_write(struct file *f, const char *buf, size_t n, loff_t *pos)
+{
+       yaffs_Object *obj;
+       int nWritten,ipos;
+       struct inode *inode;
+
+       obj  = yaffs_DentryToObject(f->f_dentry);
+       inode = f->f_dentry->d_inode;
+       nWritten = yaffs_WriteDataToFile(obj,buf,*pos,n);
+       ipos = *pos;
+       T((KERN_DEBUG"yaffs_file_write writing %d bytes, %d written at %d\n",n,nWritten,ipos));
+       if(nWritten > 0)
+       {
+               *pos += nWritten;
+               ipos = *pos;
+               if(*pos > inode->i_size)
+               {
+                       inode->i_size = *pos;
+                       T((KERN_DEBUG"yaffs_file_write size updated to %d\n",ipos));
+               }
+
+       }
+       return nWritten;
+}
+
+
+static int yaffs_readdir(struct file *f, void *dirent, filldir_t filldir)
+{
+       yaffs_Object *obj;
+       struct inode *inode = f->f_dentry->d_inode;
+       unsigned long offset, curoffs;
+       struct list_head *i;
+       yaffs_Object *l;
+
+       char name[YAFFS_MAX_NAME_LENGTH +1];
+
+       obj =  yaffs_DentryToObject(f->f_dentry);
+
+       offset = f->f_pos;
+
+       T(("yaffs_readdir: starting at %d\n",(int)offset));
+
+       if(offset == 0)
+       {
+        T((KERN_DEBUG"yaffs_readdir: entry . ino %d \n",(int)inode->i_ino));
+               if(filldir(dirent,".",1,offset,inode->i_ino,DT_DIR) < 0)
+               {
+                       goto out;
+               }
+               offset++;
+               f->f_pos++;
+       }
+       if(offset == 1)
+       {
+               T((KERN_DEBUG"yaffs_readdir: entry .. ino %d \n",(int)f->f_dentry->d_parent->d_inode->i_ino));
+               if(filldir(dirent,"..",2,offset,f->f_dentry->d_parent->d_inode->i_ino,DT_DIR) < 0)
+               {
+                       goto out;
+               }
+               offset++;
+               f->f_pos++;
+       }
+
+       curoffs = 1;
+
+       //down(&obj->sem);
+
+
+       list_for_each(i,&obj->variant.directoryVariant.children)
+       {
+               curoffs++;
+               if(curoffs >= offset)
+               {
+                       l = list_entry(i, yaffs_Object,siblings);
+
+                       yaffs_GetObjectName(l,name,YAFFS_MAX_NAME_LENGTH+1);
+                       T((KERN_DEBUG"yaffs_readdir: %s inode %d\n",name,yaffs_GetObjectInode(l)));
+
+                       if(filldir(dirent,
+                                          name,
+                                          strlen(name),
+                                          offset,
+                                          yaffs_GetObjectInode(l),
+                                          yaffs_GetObjectType(l))
+                                          < 0)
+                       {
+                               goto up_and_out;
+                       }
+
+                       offset++;
+                       f->f_pos++;
+               }
+       }
+
+  up_and_out:
+
+       //up(&obj->sem);
+
+  out:
+       return 0;
+}
+
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+static int yaffs_mknod(struct inode *dir, struct dentry *dentry, int mode, int dev)
+{
+       struct inode *inode;
+
+       yaffs_Object *obj = NULL;
+       yaffs_Object *parent = yaffs_InodeToObject(dir);
+
+       int error = -ENOSPC;
+
+       if(parent)
+       {
+               T((KERN_DEBUG"yaffs_mknod: parent object %d type %d\n",
+                                        parent->objectId,parent->variantType));
+       }
+       else
+       {
+               T((KERN_DEBUG"yaffs_mknod: could not get parent object\n"));
+               return -EPERM;
+       }
+
+       T(("yaffs_mknod: making oject for %s, mode %x\n",
+                               dentry->d_name.name, mode));
+
+       switch (mode & S_IFMT)
+       {
+               default:
+
+                       break;
+               case S_IFREG:   // file
+                       T((KERN_DEBUG"yaffs_mknod: making file\n"));
+                       obj = yaffs_MknodFile(parent,dentry->d_name.name,mode,current->uid, current->gid);
+                       break;
+               case S_IFDIR:   // directory
+                       T((KERN_DEBUG"yaffs_mknod: making directory\n"));
+                       obj = yaffs_MknodDirectory(parent,dentry->d_name.name,mode,current->uid, current->gid);
+                       break;
+               case S_IFLNK:   // symlink
+                       T((KERN_DEBUG"yaffs_mknod: making file\n"));
+                       obj = NULL; // Todo
+                       break;
+       }
+
+       if(obj)
+       {
+               inode = yaffs_get_inode(dir->i_sb, mode, dev, obj);
+
+// did not fix dir bug         if((mode & S_IFMT) == S_IFDIR)  atomic_inc(&inode->i_count);
+
+               d_instantiate(dentry, inode);
+               T((KERN_DEBUG"yaffs_mknod created object %d count = %d\n",obj->objectId,atomic_read(&inode->i_count)));
+               error = 0;
+       }
+       else
+       {
+               T((KERN_DEBUG"yaffs_mknod failed making object\n"));
+               error = -ENOMEM;
+       }
+
+
+       return error;
+}
+
+static int yaffs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
+{
+       int retVal;
+       T((KERN_DEBUG"yaffs_mkdir\n"));
+       retVal =  yaffs_mknod(dir, dentry, mode | S_IFDIR, 0);
+#if 0
+ // attempt to fix dir bug - didn't work
+       if(!retVal)
+       {
+               dget(dentry);
+       }
+#endif
+       return retVal;
+}
+
+static int yaffs_create(struct inode *dir, struct dentry *dentry, int mode)
+{
+       T((KERN_DEBUG"yaffs_create\n"));
+       return yaffs_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+
+static int yaffs_unlink(struct inode * dir, struct dentry *dentry)
+{
+
+       T((KERN_DEBUG"yaffs_unlink\n"));
+
+       if(yaffs_Unlink(yaffs_InodeToObject(dir),dentry->d_name.name) == YAFFS_OK)
+       {
+               return 0;
+       }
+       else
+       {
+               return -ENOTEMPTY;
+       }
+}
+
+
+/*
+ * Link a file..
+ */
+static int yaffs_link(struct dentry *old_dentry, struct inode * dir, struct dentry * dentry)
+{
+       struct inode *inode = old_dentry->d_inode;
+
+       T((KERN_DEBUG"yaffs_link\n"));
+
+       return -EPERM; //Todo
+
+
+       if (S_ISDIR(inode->i_mode))
+               return -EPERM;
+
+
+       return 0;
+}
+
+
+static int yaffs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
+{
+       int error;
+
+       T((KERN_DEBUG"yaffs_symlink\n"));
+
+
+       return -ENOMEM; //Todo
+
+       error = yaffs_mknod(dir, dentry, S_IFLNK | S_IRWXUGO, 0);
+       return error;
+}
+
+static int yaffs_sync_object(struct file * file, struct dentry *dentry, int datasync)
+{
+
+       T((KERN_DEBUG"yaffs_sync_object\n"));
+       yaffs_FlushFile(yaffs_DentryToObject(dentry));
+       return 0;
+}
+
+/*
+ * The VFS layer already does all the dentry stuff for rename.
+ */
+static int yaffs_rename(struct inode * old_dir, struct dentry *old_dentry, struct inode * new_dir,struct dentry *new_dentry)
+{
+
+
+       if( yaffs_RenameObject(yaffs_InodeToObject(old_dir),old_dentry->d_name.name,
+                              yaffs_InodeToObject(new_dir),new_dentry->d_name.name) == YAFFS_OK)
+       {
+               return 0;
+       }
+       else
+       {
+               return -ENOTEMPTY;
+       }
+
+
+}
+
+static int yaffs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+       struct inode *inode = dentry->d_inode;
+       int error;
+
+       T((KERN_DEBUG"yaffs_setattr\n"));
+
+       if((error = inode_change_ok(inode,attr)) == 0)
+       {
+
+               if(yaffs_SetAttributes(yaffs_InodeToObject(inode),attr) == YAFFS_OK)
+               {
+                       error = 0;
+               }
+               else
+               {
+                       error = -EPERM;
+               }
+
+               inode_setattr(inode,attr);
+       }
+       return error;
+}
+
+static int yaffs_statfs(struct super_block *sb, struct statfs *buf)
+{
+       T((KERN_DEBUG"yaffs_statfs\n"));
+
+       buf->f_type = YAFFS_MAGIC;
+       buf->f_bsize = YAFFS_BYTES_PER_CHUNK;
+       buf->f_namelen = 255;
+       buf->f_blocks = yaffs_SuperToDevice(sb)->nBlocks * YAFFS_CHUNKS_PER_BLOCK;
+       buf->f_files = 0;
+       buf->f_ffree = 0;
+       buf->f_bavail = yaffs_GetNumberOfFreeChunks(yaffs_SuperToDevice(sb));
+       return 0;
+}
+
+static void yaffs_read_inode (struct inode *inode)
+{
+
+       yaffs_Object *obj ;
+
+       T((KERN_DEBUG"yaffs_read_inode for %d\n",(int)inode->i_ino));
+
+       obj  = yaffs_FindObjectByNumber(yaffs_SuperToDevice(inode->i_sb),inode->i_ino);
+
+       yaffs_FillInodeFromObject(inode,obj);
+}
+
+
+static struct super_block *yaffs_internal_read_super(int useRam, struct super_block * sb, void * data, int silent)
+{
+       struct inode * inode;
+       struct dentry * root;
+       yaffs_Device *dev;
+
+
+       T(("yaffs_read_super:\n"));
+       sb->s_blocksize = YAFFS_BYTES_PER_CHUNK;
+       sb->s_blocksize_bits = YAFFS_CHUNK_SIZE_SHIFT;
+       sb->s_magic = YAFFS_MAGIC;
+       sb->s_op = &yaffs_super_ops;
+
+       if(!sb)
+               printk(KERN_INFO"sb is NULL\n");
+       else if(!sb->s_dev)
+               printk(KERN_INFO"sb->s_dev is NULL\n");
+       else if(! kdevname(sb->s_dev))
+               printk(KERN_INFO"kdevname is NULL\n");
+       else
+               printk(KERN_INFO"dev is %d name is \"%s\"\n", sb->s_dev, kdevname(sb->s_dev));
+
+
+       if(useRam)
+       {
+
+#if YAFFS_RAM_ENABLED
+               // Set the yaffs_Device up for ram emulation
+
+               sb->u.generic_sbp =     dev = kmalloc(sizeof(yaffs_Device),GFP_KERNEL);
+               if(!dev)
+               {
+                       // Deep shit could not allocate device structure
+                       printk(KERN_DEBUG"yaffs_read_super: Failed trying to allocate yaffs_Device. Terminating debug.\n");
+                       return NULL;
+               }
+
+               memset(dev,0,sizeof(yaffs_Device));
+               dev->genericDevice = NULL; // Not used for RAM emulation.
+
+               dev->nBlocks = YAFFS_RAM_EMULATION_SIZE / (YAFFS_CHUNKS_PER_BLOCK * YAFFS_BYTES_PER_CHUNK);
+               dev->startBlock = 1;  // Don't use block 0
+               dev->endBlock = dev->nBlocks - 1;
+
+               dev->writeChunkToNAND = nandemul_WriteChunkToNAND;
+               dev->readChunkFromNAND = nandemul_ReadChunkFromNAND;
+               dev->eraseBlockInNAND = nandemul_EraseBlockInNAND;
+               dev->initialiseNAND = nandemul_InitialiseNAND;
+#endif
+
+       }
+       else
+       {
+#ifdef YAFFS_MTD_ENABLED
+               struct mtd_info *mtd;
+
+               // Hope it's a NAND mtd
+               mtd = get_mtd_device(NULL, MINOR(sb->s_dev));
+               if (!mtd)
+               {
+                       printk(KERN_DEBUG "yaffs: MTD device #%u doesn't appear to exist\n", MINOR(sb->s_dev));
+                       return NULL;
+               }
+               if(mtd->type != MTD_NANDFLASH)
+               {
+                       printk(KERN_DEBUG "yaffs: MTD device is not NAND it's type %d\n", mtd->type);
+                       return NULL;
+               }
+
+               if(!mtd->erase ||
+                  !mtd->read  ||
+                  !mtd->write ||
+                  !mtd->read_oob ||
+                  !mtd->write_oob)
+               {
+                       printk(KERN_DEBUG "yaffs: MTD device does not support required functions\n");
+                       return NULL;
+               }
+
+               if(mtd->oobblock != YAFFS_BYTES_PER_CHUNK ||
+                  mtd->oobsize != YAFFS_BYTES_PER_SPARE)
+               {
+                       printk(KERN_DEBUG "yaffs: MTD device does not support have the right page sizes\n");
+                       return NULL;
+               }
+
+
+               // OK, so if we got here, we have an MTD that's NAND and looks
+               // like it has the right capabilities
+               // Set the yaffs_Device up for ram emulation
+
+               sb->u.generic_sbp =     dev = kmalloc(sizeof(yaffs_Device),GFP_KERNEL);
+               if(!dev)
+               {
+                       // Deep shit could not allocate device structure
+                       printk(KERN_DEBUG"yaffs_read_super: Failed trying to allocate yaffs_Device. Terminating debug.\n");
+                       return NULL;
+               }
+
+               memset(dev,0,sizeof(yaffs_Device));
+               dev->genericDevice = mtd;
+
+               // Set up the memory size parameters....
+
+               dev->nBlocks = mtd->size / (YAFFS_CHUNKS_PER_BLOCK * YAFFS_BYTES_PER_CHUNK);
+               dev->startBlock = 1;  // Don't use block 0
+               dev->endBlock = dev->nBlocks - 1;
+
+               // ... and the functions.
+               dev->writeChunkToNAND = nandmtd_WriteChunkToNAND;
+               dev->readChunkFromNAND = nandmtd_ReadChunkFromNAND;
+               dev->eraseBlockInNAND = nandmtd_EraseBlockInNAND;
+               dev->initialiseNAND = nandmtd_InitialiseNAND;
+
+#endif
+       }
+
+
+
+       yaffs_GutsInitialise(yaffs_SuperToDevice(sb));
+       T(("yaffs_read_super: guts initialised\n"));
+
+       // Create root inode
+       inode = yaffs_get_inode(sb, S_IFDIR | 0755, 0,yaffs_Root(yaffs_SuperToDevice(sb)));
+       if (!inode)
+               return NULL;
+
+       T(("yaffs_read_super: got root inode\n"));
+
+
+       root = d_alloc_root(inode);
+
+       T(("yaffs_read_super: d_alloc_root done\n"));
+
+       if (!root) {
+               iput(inode);
+               return NULL;
+       }
+       sb->s_root = root;
+
+       T(("yaffs_read_super: done\n"));
+       return sb;
+}
+
+#ifdef YAFFS_MTD_ENABLED
+static struct super_block *yaffs_read_super(struct super_block * sb, void * data, int silent)
+{
+       return yaffs_internal_read_super(0,sb,data,silent);
+}
+
+static DECLARE_FSTYPE(yaffs_fs_type, "yaffs", yaffs_read_super, FS_REQUIRES_DEV);
+#endif
+
+#ifdef YAFFS_RAM_ENABLED
+
+static struct super_block *yaffs_ram_read_super(struct super_block * sb, void * data, int silent)
+{
+       return yaffs_internal_read_super(1,sb,data,silent);
+}
+
+static DECLARE_FSTYPE(yaffs_ram_fs_type, "yaffsram", yaffs_ram_read_super, FS_SINGLE);
+#endif // YAFFS_RAM_ENABLED
+
+
+static struct proc_dir_entry *my_proc_entry;
+
+
+static int  yaffs_proc_read(
+        char *page,
+       char **start,
+       off_t offset,
+       int count,
+       int *eof,
+       void *data
+       )
+{
+
+       static char my_buffer[1000];
+
+       if (offset > 0) return 0;
+
+       /* Fill the buffer and get its length */
+       sprintf( my_buffer,
+               "YAFFS built:"__DATE__ " "__TIME__"\n"
+
+       );
+
+       strcpy(page,my_buffer);
+       return strlen(my_buffer);
+}
+
+static int __init init_yaffs_fs(void)
+{
+       int error = 0;
+
+       printk(KERN_DEBUG "yaffs " __DATE__ " " __TIME__ " Initialisation\n");
+    /* Install the proc_fs entry */
+    my_proc_entry = create_proc_read_entry("yaffs",
+                                           S_IRUGO | S_IFREG,
+                                          &proc_root,
+                                          yaffs_proc_read,
+                                          NULL);
+    if(!my_proc_entry)
+    {
+       return -ENOMEM;
+    }
+
+#ifdef YAFFS_RAM_ENABLED
+
+    error = register_filesystem(&yaffs_ram_fs_type);
+    if(error)
+    {
+       return error;
+    }
+#endif //YAFFS_RAM_ENABLED
+
+#ifdef YAFFS_MTD_ENABLED
+       error = register_filesystem(&yaffs_fs_type);
+       if(error)
+       {
+#ifdef YAFFS_RAM_ENABLED
+               unregister_filesystem(&yaffs_ram_fs_type);
+#endif //YAFFS_RAM_ENABLED
+       }
+#endif // YAFFS_MTD_ENABLED
+
+       return error;
+}
+
+static void __exit exit_yaffs_fs(void)
+{
+       printk(KERN_DEBUG "yaffs " __DATE__ " " __TIME__ " Clean up\n");
+
+    remove_proc_entry("yaffs",&proc_root);
+
+#ifdef YAFFS_RAM_ENABLED
+       unregister_filesystem(&yaffs_ram_fs_type);
+#endif
+#ifdef YAFFS_MTD_ENABLED
+       unregister_filesystem(&yaffs_fs_type);
+#endif
+
+}
+
+module_init(init_yaffs_fs)
+module_exit(exit_yaffs_fs)
+
+MODULE_DESCRIPTION("YAFFS - a NAND specific flash file system");
+MODULE_AUTHOR("Charles Manning, Aleph One Ltd., 2002");
+MODULE_LICENSE("GPL");
+
diff --git a/yaffs_guts.c b/yaffs_guts.c
new file mode 100644 (file)
index 0000000..6bc6136
--- /dev/null
@@ -0,0 +1,3079 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system.
+ * yaffs_guts.c  The main guts of YAFFS
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+ //yaffs_guts.c
+
+#include "yportenv.h"
+
+#include "yaffsinterface.h"
+#include "yaffs_guts.h"
+
+
+#if 0
+#define T(x) printf x
+#else
+#define T(x)
+#endif
+
+
+// countBits is a quick way of counting the number of bits in a byte.
+// ie. countBits[n] holds the number of 1 bits in a byte with the value n.
+
+static const char yaffs_countBits[256] =
+{
+0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
+4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8
+};
+
+
+
+// Device info
+//static yaffs_Device *yaffs_device;
+//yaffs_Object *yaffs_rootDir;
+//yaffs_Object *yaffs_lostNFound;
+
+
+
+// Local prototypes
+static int yaffs_CheckObjectHashSanity(yaffs_Device *dev);
+static void yaffs_LoadTagsIntoSpare(yaffs_Spare *sparePtr, yaffs_Tags *tagsPtr);
+static void yaffs_GetTagsFromSpare(yaffs_Spare *sparePtr,yaffs_Tags *tagsPtr);
+static int yaffs_PutChunkIntoFile(yaffs_Object *in,int chunkInInode, int chunkInNAND);
+
+static yaffs_Object *yaffs_CreateNewObject(yaffs_Device *dev,int number,yaffs_ObjectType type);
+static void yaffs_AddObjectToDirectory(yaffs_Object *directory, yaffs_Object *obj);
+static int yaffs_UpdateObjectHeader(yaffs_Object *in,const char *name);
+static void yaffs_DeleteChunk(yaffs_Device *dev,int chunkId);
+static void yaffs_RemoveObjectFromDirectory(yaffs_Object *obj);
+static int yaffs_CheckStructures(void);
+static yaffs_Object *yaffs_GetEquivalentObject(yaffs_Object *obj);
+
+loff_t yaffs_GetFileSize(yaffs_Object *obj);
+
+
+static int yaffs_AllocateChunk(yaffs_Device *dev,int useReserve);
+
+#if YAFFS_PARANOID
+static int yaffs_CheckFileSanity(yaffs_Object *in)
+#else
+#define yaffs_CheckFileSanity(in)
+#endif
+
+static int __inline__ yaffs_HashFunction(int n)
+{
+       return (n % YAFFS_NOBJECT_BUCKETS);
+}
+
+
+yaffs_Object *yaffs_Root(yaffs_Device *dev)
+{
+       return dev->rootDir;
+}
+
+yaffs_Object *yaffs_LostNFound(yaffs_Device *dev)
+{
+       return dev->lostNFoundDir;
+}
+
+
+static int yaffs_WriteChunkToNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND, const __u8 *data, yaffs_Spare *spare)
+{
+       return dev->writeChunkToNAND(dev,chunkInNAND,data,spare);
+}
+
+int yaffs_ReadChunkFromNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare)
+{
+       return dev->readChunkFromNAND(dev,chunkInNAND,data,spare);
+}
+
+int yaffs_EraseBlockInNAND(struct yaffs_DeviceStruct *dev,int blockInNAND)
+{
+       return dev->eraseBlockInNAND(dev,blockInNAND);
+}
+
+int yaffs_InitialiseNAND(struct yaffs_DeviceStruct *dev)
+{
+       return dev->initialiseNAND(dev);
+}
+
+static int yaffs_WriteNewChunkToNAND(struct yaffs_DeviceStruct *dev, const __u8 *data, yaffs_Spare *spare,int useReserve)
+{
+       int chunk;
+       
+       int writeOk = 0;
+       
+       do{
+               chunk = yaffs_AllocateChunk(dev,useReserve);
+       
+               if(chunk >= 0)
+               {
+                       writeOk =  yaffs_WriteChunkToNAND(dev,chunk,data,spare);
+                       if(writeOk)
+                       {
+                               //Todo read-back and verify
+                               // If verify fails, then delete this chunk and try again
+                       }
+               }
+       } while(chunk >= 0 && ! writeOk);
+       
+       return chunk;
+}
+
+
+
+
+///////////////////////// Object management //////////////////
+// List of spare objects
+// The list is hooked together using the first pointer
+// in the object
+
+// static yaffs_Object *yaffs_freeObjects = NULL;
+
+// static int yaffs_nFreeObjects;
+
+// static yaffs_ObjectList *yaffs_allocatedObjectList = NULL;
+
+// static yaffs_ObjectBucket yaffs_objectBucket[YAFFS_NOBJECT_BUCKETS];
+
+
+static __u16 yaffs_CalcNameSum(const char *name)
+{
+       __u16 sum = 0;
+       __u16 i = 1;
+       
+       __u8 *bname = (__u8 *)name;
+       
+       while (*bname)
+       {
+               sum += (*bname) * i;
+               i++;
+               bname++;
+       }
+       return sum;
+}
+
+
+void yaffs_CalcECC(const __u8 *buffer, yaffs_Spare *spare)
+{
+
+       // Todo do nothing now. Need to put in ecc
+       spare->ecc1[0] = spare->ecc1[1] = spare->ecc1[2] = 0xFF;
+       spare->ecc2[0] = spare->ecc2[1] = spare->ecc2[2] = 0xFF;
+}
+
+void yaffs_CalcTagsECC(yaffs_Tags *tags)
+{
+       // Todo don't do anything yet. Need to calculate ecc
+       tags->ecc = 0xFFFFFFFF;
+}
+
+
+
+///////////////////////// TNODES ///////////////////////
+
+// List of spare tnodes
+// The list is hooked together using the first pointer
+// in the tnode.
+
+//static yaffs_Tnode *yaffs_freeTnodes = NULL;
+
+// static int yaffs_nFreeTnodes;
+
+//static yaffs_TnodeList *yaffs_allocatedTnodeList = NULL;
+
+
+
+// yaffs_CreateTnodes creates a bunch more tnodes and
+// adds them to the tnode free list.
+// Don't use this function directly
+
+static int yaffs_CreateTnodes(yaffs_Device *dev,int nTnodes)
+{
+    int i;
+    yaffs_Tnode *newTnodes;
+    yaffs_TnodeList *tnl;
+    
+    if(nTnodes < 1) return YAFFS_OK;
+   
+       // make these things
+       
+    newTnodes = YMALLOC(nTnodes * sizeof(yaffs_Tnode));
+   
+    if (!newTnodes)
+    {
+               YALERT("Could not malloc tnodes");
+               return YAFFS_FAIL;
+    }
+    
+    // Hook them into the free list
+    for(i = 0; i < nTnodes - 1; i++)
+    {
+       newTnodes[i].internal[0] = &newTnodes[i+1];
+    }
+       
+       newTnodes[nTnodes - 1].internal[0] = dev->freeTnodes;
+       dev->freeTnodes = newTnodes;
+       dev->nFreeTnodes+= nTnodes;
+       dev->nTnodesCreated += nTnodes;
+
+       // Now add this bunch of tnodes to a list for freeing up.
+
+       tnl = YMALLOC(sizeof(yaffs_TnodeList));
+       if(!tnl)
+       {
+               YALERT("Could not add tnodes to management list");
+       }
+       else
+       {
+               tnl->tnodes = newTnodes;
+               tnl->next = dev->allocatedTnodeList;
+               dev->allocatedTnodeList = tnl;
+       }
+
+
+       YINFO("Tnodes created");
+
+
+       return YAFFS_OK;
+}
+
+
+// GetTnode gets us a clean tnode. Tries to make allocate more if we run out
+static yaffs_Tnode *yaffs_GetTnode(yaffs_Device *dev)
+{
+       yaffs_Tnode *tn = NULL;
+       
+       // If there are none left make more
+       if(!dev->freeTnodes)
+       {
+               yaffs_CreateTnodes(dev,YAFFS_ALLOCATION_NTNODES);
+       }
+       
+       if(dev->freeTnodes)
+       {
+               tn = dev->freeTnodes;
+               dev->freeTnodes = dev->freeTnodes->internal[0];
+               dev->nFreeTnodes--;
+               // zero out
+               memset(tn,0,sizeof(yaffs_Tnode));
+       }
+       
+
+       return tn;
+}
+
+
+// FreeTnode frees up a tnode and puts it back on the free list
+static void yaffs_FreeTnode(yaffs_Device*dev, yaffs_Tnode *tn)
+{
+       tn->internal[0] = dev->freeTnodes;
+       dev->freeTnodes = tn;
+       dev->nFreeTnodes++;
+}
+
+
+static void yaffs_DeinitialiseTnodes(yaffs_Device*dev)
+{
+       // Free the list of allocated tnodes
+       
+       while(dev->allocatedTnodeList)
+       {
+               YFREE(dev->allocatedTnodeList->tnodes);
+               dev->allocatedTnodeList =  dev->allocatedTnodeList->next;
+       }
+       
+       dev->freeTnodes = NULL;
+       dev->nFreeTnodes = 0;
+}
+
+static void yaffs_InitialiseTnodes(yaffs_Device*dev)
+{
+       dev->allocatedTnodeList = NULL;
+       dev->freeTnodes = NULL;
+       dev->nFreeTnodes = 0;
+       dev->nTnodesCreated = 0;
+
+}
+
+void yaffs_TnodeTest(yaffs_Device *dev)
+{
+
+       int i;
+       int j;
+       yaffs_Tnode *tn[1000];
+       
+       YINFO("Testing TNodes");
+       
+       for(j = 0; j < 50; j++)
+       {
+               for(i = 0; i < 1000; i++)
+               {
+                       tn[i] = yaffs_GetTnode(dev);
+                       if(!tn[i])
+                       {
+                               YALERT("Getting tnode failed");
+                       }
+               }
+               for(i = 0; i < 1000; i+=3)
+               {
+                       yaffs_FreeTnode(dev,tn[i]);
+                       tn[i] = NULL;
+               }
+               
+       }
+}
+
+////////////////// END OF TNODE MANIPULATION ///////////////////////////
+
+/////////////// Functions to manipulate the look-up tree (made up of tnodes)
+// The look up tree is represented by the top tnode and the number of topLevel
+// in the tree. 0 means only the level 0 tnode is in the tree.
+
+
+// FindLevel0Tnode finds the level 0 tnode, if one exists.
+// Used when reading.....
+static yaffs_Tnode *yaffs_FindLevel0Tnode(yaffs_Device *dev,yaffs_FileStructure *fStruct, __u32 chunkId)
+{
+       
+       yaffs_Tnode *tn = fStruct->top;
+       __u32 i;
+       int requiredTallness;   
+       int level = fStruct->topLevel;
+       
+       // Check sane level and chunk Id
+       if(level < 0 || level > YAFFS_TNODES_MAX_LEVEL)
+       {
+               char str[50];
+               sprintf(str,"Bad level %d",level);
+               YALERT(str);
+               return NULL;
+       }
+       if(chunkId > YAFFS_MAX_CHUNK_ID)
+       {
+               char str[50];
+               sprintf(str,"Bad chunkId %d",chunkId);
+               YALERT(str);
+               return NULL;
+       }
+
+       // First check we're tall enough (ie enough topLevel)
+       
+       i = chunkId >> (dev->chunkGroupBits + YAFFS_TNODES_LEVEL0_BITS);
+       requiredTallness = 0;
+       while(i)
+       {
+               i >>= YAFFS_TNODES_INTERNAL_BITS;
+               requiredTallness++;
+       }
+       
+       
+       if(requiredTallness > fStruct->topLevel)
+       {
+               // Not tall enough, so we can't find it, return NULL.
+               return NULL;
+       }
+               
+       
+       // Traverse down to level 0
+       while (level > 0 && tn)
+       {
+           tn = tn->internal[(chunkId >>(dev->chunkGroupBits + YAFFS_TNODES_LEVEL0_BITS + (level-1) * YAFFS_TNODES_INTERNAL_BITS)) & 
+                              YAFFS_TNODES_INTERNAL_MASK]; 
+               level--;
+       
+       }
+       
+       return tn;              
+}
+
+// AddOrFindLevel0Tnode finds the level 0 tnode if it exists, otherwise first expands the tree.
+// This happens in two steps:
+//  1. If the tree isn't tall enough, then make it taller.
+//  2. Scan down the tree towards the level 0 tnode adding tnodes if required.
+//
+// Used when modifying the tree.
+//
+static yaffs_Tnode *yaffs_AddOrFindLevel0Tnode(yaffs_Device *dev, yaffs_FileStructure *fStruct, __u32 chunkId)
+{
+       
+       yaffs_Tnode *tn; 
+       
+       int requiredTallness;
+       
+       __u32 i;
+       __u32 l;
+       
+       
+       T(("AddOrFind topLevel=%d, chunk=%d",fStruct->topLevel,chunkId));
+       
+       // Check sane level and page Id
+       if(fStruct->topLevel < 0 || fStruct->topLevel > YAFFS_TNODES_MAX_LEVEL)
+       {
+               char str[50];
+               sprintf(str,"Bad level %d",fStruct->topLevel);
+               YALERT(str);
+               return NULL;
+       }
+       
+       if(chunkId > YAFFS_MAX_CHUNK_ID)
+       {
+               char str[50];
+               sprintf(str,"Bad chunkId %d",chunkId);
+               YALERT(str);
+               return NULL;
+       }
+       
+       // First check we're tall enough (ie enough topLevel)
+       
+       i = chunkId >> (dev->chunkGroupBits + YAFFS_TNODES_LEVEL0_BITS);
+       requiredTallness = 0;
+       while(i)
+       {
+               i >>= YAFFS_TNODES_INTERNAL_BITS;
+               requiredTallness++;
+       }
+       
+       T((" required=%d",requiredTallness));
+       
+       
+       if(requiredTallness > fStruct->topLevel)
+       {
+               // Not tall enough,gotta make the tree taller
+               for(i = fStruct->topLevel; i < requiredTallness; i++)
+               {
+                       T((" add new top"));
+                       
+                       tn = yaffs_GetTnode(dev);
+                       
+                       if(tn)
+                       {
+                               tn->internal[0] = fStruct->top;
+                               fStruct->top = tn;
+                       }
+                       else
+                       {
+                               YALERT("No more tnodes");
+                       }
+               }
+               
+               fStruct->topLevel = requiredTallness;
+       }
+       
+       
+       // Traverse down to level 0, adding anything we need
+       
+       l = fStruct->topLevel;
+       tn = fStruct->top;
+       while (l > 0 && tn)
+       {
+               i = (chunkId >> (dev->chunkGroupBits +YAFFS_TNODES_LEVEL0_BITS + (l-1) * YAFFS_TNODES_INTERNAL_BITS)) & 
+                              YAFFS_TNODES_INTERNAL_MASK;
+                              
+               T((" [%d:%d]",l,i));
+               
+           if(!tn->internal[i])
+           {
+               T((" added"));
+               
+               tn->internal[i] = yaffs_GetTnode(dev);
+           }
+           
+           tn =        tn->internal[i];
+               l--;
+       
+       }
+       
+       T(("\n"));
+       
+       return tn;              
+}
+
+
+// Pruning removes any part of the file structure tree that is beyond the
+// bounds of the file.
+// A file should only get pruned when its size is reduced.
+//
+// Before pruning, the chunks must be pulled from the tree and the
+// level 0 tnode entries must be zeroed out.
+// Could also use this for file deletion, but that's probably better handled
+// by a special case.
+
+// yaffs_PruneWorker should only be called by yaffs_PruneFileStructure()
+
+static yaffs_Tnode *yaffs_PruneWorker(yaffs_Device *dev, yaffs_Tnode *tn, __u32 level, int del0)
+{
+       int i;
+       int hasData;
+       
+       if(tn)
+       {
+               hasData = 0;
+               
+               for(i = 0; i < YAFFS_NTNODES_INTERNAL; i++)
+               {
+                   if(tn->internal[i] && level > 0)
+                   {
+                       tn->internal[i] = yaffs_PruneWorker(dev,tn->internal[i],level - 1, ( i == 0) ? del0 : 1);
+                   }
+                   
+                   if(tn->internal[i])
+                   {
+                       hasData++;
+                       }
+               }
+               
+               if(hasData == 0 && del0)
+               {
+                       // Free and return NULL
+                       
+                       yaffs_FreeTnode(dev,tn);
+                       tn = NULL;
+               }
+               
+       }
+
+       return tn;
+       
+}
+
+static int yaffs_PruneFileStructure(yaffs_Device *dev, yaffs_FileStructure *fStruct)
+{
+       int i;
+       int hasData;
+       int done = 0;
+       yaffs_Tnode *tn;
+       
+       if(fStruct->topLevel > 0)
+       {
+               fStruct->top = yaffs_PruneWorker(dev,fStruct->top, fStruct->topLevel,0);
+               
+               // Now we have a tree with all the non-zero branches NULL but the height
+               // is the same as it was.
+               // Let's see if we can trim internal tnodes to shorten the tree.
+               // We can do this if only the 0th element in the tnode is in use 
+               // (ie all the non-zero are NULL)
+               
+               while(fStruct->topLevel && !done)
+               {
+                       tn = fStruct->top;
+                       
+                       hasData = 0;
+                       for(i = 1; i <YAFFS_NTNODES_INTERNAL; i++)
+                       {
+                               if(tn->internal[i])
+                       {
+                               hasData++;
+                               }
+                       }
+                       
+                       if(!hasData)
+                       {
+                               fStruct->top = tn->internal[0];
+                               fStruct->topLevel--;
+                               yaffs_FreeTnode(dev,tn);
+                       }
+                       else
+                       {
+                               done = 1;
+                       }
+               }
+       }
+       
+       return YAFFS_OK;
+}
+
+
+
+
+/////////////////////// End of File Structure functions. /////////////////
+
+// yaffs_CreateFreeObjects creates a bunch more objects and
+// adds them to the object free list.
+static int yaffs_CreateFreeObjects(yaffs_Device *dev, int nObjects)
+{
+    int i;
+    yaffs_Object *newObjects;
+    yaffs_ObjectList *list;
+    
+    if(nObjects < 1) return YAFFS_OK;
+   
+       // make these things
+       
+    newObjects = YMALLOC(nObjects * sizeof(yaffs_Object));
+   
+    if (!newObjects)
+    {
+               YALERT("Could not allocate more objects");
+               return YAFFS_FAIL;
+    }
+    
+    // Hook them into the free list
+    for(i = 0; i < nObjects - 1; i++)
+    {
+       (yaffs_Object *)newObjects[i].siblings.next = &newObjects[i+1];
+    }
+       
+       newObjects[nObjects - 1].siblings.next = (void *)dev->freeObjects;
+       dev->freeObjects = newObjects;
+       dev->nFreeObjects+= nObjects;
+       dev->nObjectsCreated+= nObjects;
+       
+       // Now add this bunch of Objects to a list for freeing up.
+       
+       list = YMALLOC(sizeof(yaffs_ObjectList));
+       if(!list)
+       {
+               YALERT("Could not add Objects to management list");
+       }
+       else
+       {
+               list->objects = newObjects;
+               list->next = dev->allocatedObjectList;
+               dev->allocatedObjectList = list;
+       }
+       
+       
+       YINFO("Objects created");
+       
+       
+       return YAFFS_OK;
+}
+
+
+// AllocateEmptyObject gets us a clean Object. Tries to make allocate more if we run out
+static yaffs_Object *yaffs_AllocateEmptyObject(yaffs_Device *dev)
+{
+       yaffs_Object *tn = NULL;
+       
+       // If there are none left make more
+       if(!dev->freeObjects)
+       {
+               yaffs_CreateFreeObjects(dev,YAFFS_ALLOCATION_NOBJECTS);
+       }
+       
+       if(dev->freeObjects)
+       {
+               tn = dev->freeObjects;
+               dev->freeObjects = (yaffs_Object *)(dev->freeObjects->siblings.next);
+               dev->nFreeObjects--;
+               
+               // Now sweeten it up...
+       
+               memset(tn,0,sizeof(yaffs_Object));
+               tn->chunkId = -1;
+               tn->variantType = YAFFS_OBJECT_TYPE_UNKNOWN;
+               INIT_LIST_HEAD(&(tn->hardLinks));
+               INIT_LIST_HEAD(&(tn->hashLink));
+               INIT_LIST_HEAD(&tn->siblings);
+               
+               // Add it to the lost and found directory.
+               // NB Can't put root or lostNFound in lostNFound so
+               // check if lostNFound exists first
+               if(dev->lostNFoundDir)
+               {
+                       yaffs_AddObjectToDirectory(dev->lostNFoundDir,tn);      
+               }
+       }
+       
+
+       return tn;
+}
+
+static yaffs_Object *yaffs_CreateFakeDirectory(yaffs_Device *dev,int number,__u32 mode)
+{
+
+       yaffs_Object *obj = yaffs_CreateNewObject(dev,number,YAFFS_OBJECT_TYPE_DIRECTORY);              
+       if(obj)
+       {
+               obj->fake = 1;                  // it is fake so it has no NAND presence...
+               obj->renameAllowed= 0;  // ... and we're not allowed to rename it...
+               obj->unlinkAllowed= 0;  // ... or unlink it
+               obj->st_mode = mode;
+               obj->myDev = dev;
+               obj->chunkId = 0; // Not a valid chunk.
+       }
+       
+       return obj;
+       
+}
+
+
+static void yaffs_UnhashObject(yaffs_Object *tn)
+{
+       int bucket;
+       yaffs_Device *dev = tn->myDev;
+       
+       
+       // If it is still linked into the bucket list, free from the list
+       if(!list_empty(&tn->hashLink))
+       {
+               list_del_init(&tn->hashLink);
+               bucket =  yaffs_HashFunction(tn->objectId);
+               dev->objectBucket[bucket].count--;
+       }
+       
+}
+
+
+// FreeObject frees up a Object and puts it back on the free list
+static void yaffs_FreeObject(yaffs_Object *tn)
+{
+
+       yaffs_Device *dev = tn->myDev;
+       
+       yaffs_UnhashObject(tn);
+       
+       // Link into the free list.
+       (yaffs_Object *)(tn->siblings.next) = dev->freeObjects;
+       dev->freeObjects = tn;
+       dev->nFreeObjects++;
+}
+
+
+
+
+static void yaffs_DeinitialiseObjects(yaffs_Device *dev)
+{
+       // Free the list of allocated Objects
+       
+       while( dev->allocatedObjectList)
+       {
+               YFREE(dev->allocatedObjectList->objects);
+               dev->allocatedObjectList =  dev->allocatedObjectList->next;
+       }
+       
+       dev->freeObjects = NULL;
+       dev->nFreeObjects = 0;
+}
+
+static void yaffs_InitialiseObjects(yaffs_Device *dev)
+{
+       int i;
+       
+       dev->allocatedObjectList = NULL;
+       dev->freeObjects = NULL;
+       dev->nFreeObjects = 0;
+       
+       for(i = 0; i < YAFFS_NOBJECT_BUCKETS; i++)
+       {
+               INIT_LIST_HEAD(&dev->objectBucket[i].list);
+               dev->objectBucket[i].count = 0; 
+       }
+
+}
+
+
+
+
+
+
+int yaffs_FindNiceObjectBucket(yaffs_Device *dev)
+{
+       static int x = 0;
+       int i;
+       int l = 999;
+       int lowest = 999999;
+
+               
+       // First let's see if we can find one that's empty.
+       
+       for(i = 0; i < 10 && lowest > 0; i++)
+        {
+               x++;
+               x %=  YAFFS_NOBJECT_BUCKETS;
+               if(dev->objectBucket[x].count < lowest)
+               {
+                       lowest = dev->objectBucket[x].count;
+                       l = x;
+               }
+               
+       }
+       
+       // If we didn't find an empty list, then try
+       // looking a bit further for a short one
+       
+       for(i = 0; i < 10 && lowest > 3; i++)
+        {
+               x++;
+               x %=  YAFFS_NOBJECT_BUCKETS;
+               if(dev->objectBucket[x].count < lowest)
+               {
+                       lowest = dev->objectBucket[x].count;
+                       l = x;
+               }
+               
+       }
+       
+       return l;
+}
+
+static int yaffs_CreateNewObjectNumber(yaffs_Device *dev)
+{
+       int bucket = yaffs_FindNiceObjectBucket(dev);
+       
+       // Now find an object value that has not already been taken
+       // by scanning the list.
+       
+       int found = 0;
+       struct list_head *i;
+       
+       int n = bucket;
+
+       //yaffs_CheckObjectHashSanity();        
+       
+       while(!found)
+       {
+               found = 1;
+               n +=  YAFFS_NOBJECT_BUCKETS;
+               if(1 ||dev->objectBucket[bucket].count > 0)
+               {
+                       list_for_each(i,&dev->objectBucket[bucket].list)
+                       {
+                               // If there is already one in the list
+                               if(list_entry(i, yaffs_Object,hashLink)->objectId == n)
+                               {
+                                       found = 0;
+                               }
+                       }
+               }
+       }
+       
+       //T(("bucket %d count %d inode %d\n",bucket,yaffs_objectBucket[bucket].count,n);
+       
+       return n;       
+}
+
+void yaffs_HashObject(yaffs_Object *in)
+{
+       int bucket = yaffs_HashFunction(in->objectId);
+       yaffs_Device *dev = in->myDev;
+       
+       if(!list_empty(&in->hashLink))
+       {
+               YINFO("!!!");
+       }
+       
+       
+       list_add(&in->hashLink,&dev->objectBucket[bucket].list);
+       dev->objectBucket[bucket].count++;
+
+}
+
+yaffs_Object *yaffs_FindObjectByNumber(yaffs_Device *dev,int number)
+{
+       int bucket = yaffs_HashFunction(number);
+       struct list_head *i;
+       yaffs_Object *in;
+       
+       list_for_each(i,&dev->objectBucket[bucket].list)
+       {
+               // Lookm if it is in the list
+               in = list_entry(i, yaffs_Object,hashLink);
+               if(in->objectId == number)
+               {
+                       return in;
+               }
+       }
+       
+       return NULL;
+}
+
+
+
+yaffs_Object *yaffs_CreateNewObject(yaffs_Device *dev,int number,yaffs_ObjectType type)
+{
+               
+       yaffs_Object *theObject;
+
+       if(number < 0)
+       {
+               number = yaffs_CreateNewObjectNumber(dev);
+       }
+       
+       theObject = yaffs_AllocateEmptyObject(dev);
+       
+       if(theObject)
+       {
+               theObject->fake = 0;
+               theObject->renameAllowed = 1;
+               theObject->unlinkAllowed = 1;
+               theObject->objectId = number;
+               theObject->myDev = dev;
+               yaffs_HashObject(theObject);
+               theObject->variantType = type;
+               theObject->st_atime = theObject->st_mtime =     theObject->st_ctime = CURRENT_TIME;
+
+               switch(type)
+               {
+                       case YAFFS_OBJECT_TYPE_FILE: 
+                               theObject->variant.fileVariant.fileSize = 0;
+                               theObject->variant.fileVariant.topLevel = 0;
+                               theObject->variant.fileVariant.top  = yaffs_GetTnode(dev);
+                               break;
+                       case YAFFS_OBJECT_TYPE_DIRECTORY:
+                               INIT_LIST_HEAD(&theObject->variant.directoryVariant.children);
+                               break;
+                       case YAFFS_OBJECT_TYPE_SYMLINK:
+                               break;
+                       case YAFFS_OBJECT_TYPE_HARDLINK:
+                               break;
+                       case YAFFS_OBJECT_TYPE_UNKNOWN:
+                               // todo this should not happen
+               }
+       }
+       
+       return theObject;
+}
+
+yaffs_Object *yaffs_FindOrCreateObjectByNumber(yaffs_Device *dev, int number,yaffs_ObjectType type)
+{
+       yaffs_Object *theObject = NULL;
+       
+       if(number >= 0)
+       {
+               theObject = yaffs_FindObjectByNumber(dev,number);
+       }
+       
+       if(!theObject)
+       {
+               theObject = yaffs_CreateNewObject(dev,number,type);
+       }
+       
+       return theObject;
+
+}
+
+char *yaffs_CloneString(const char *str)
+{
+       char *newStr = NULL;
+       
+       if(str && *str)
+       {
+               newStr = YMALLOC(strlen(str) + 1);
+               strcpy(newStr,str);
+       }
+
+       return newStr;
+       
+}
+
+//
+// Mknod (create) a new object.
+// equivalentObject only has meaning for a hard link;
+// aliasString only has meaning for a sumlink.
+yaffs_Object *yaffs_MknodObject( yaffs_ObjectType type,
+                                                                yaffs_Object *parent,
+                                                                const char *name, 
+                                                                __u32 mode,
+                                                                __u32 uid,
+                                                                __u32 gid,
+                                                                yaffs_Object *equivalentObject,
+                                                                const char *aliasString)
+{
+       yaffs_Object *in;
+
+       yaffs_Device *dev = parent->myDev;
+       
+       in = yaffs_CreateNewObject(dev,-1,type);
+       
+       if(in)
+       {
+               in->chunkId = -1;
+               in->valid = 1;
+               in->variantType = type;
+
+               in->st_mode  = mode;
+               in->st_uid   = uid;
+               in->st_gid   = gid;
+               in->st_atime =  in->st_mtime =  in->st_ctime = CURRENT_TIME;
+
+               in->sum = yaffs_CalcNameSum(name);
+               in->dirty = 1;
+               
+               yaffs_AddObjectToDirectory(parent,in);
+               
+               in->myDev = parent->myDev;
+               
+                               
+               switch(type)
+               {
+                       case YAFFS_OBJECT_TYPE_SYMLINK:
+                               in->variant.symLinkVariant.alias = yaffs_CloneString(aliasString);
+                               break;
+                       case YAFFS_OBJECT_TYPE_HARDLINK:
+                               in->variant.hardLinkVariant.equivalentObject = equivalentObject;
+                               in->variant.hardLinkVariant.equivalentObjectId = equivalentObject->objectId;
+                               list_add(&in->hardLinks,&equivalentObject->hardLinks);
+                               break;
+                       case YAFFS_OBJECT_TYPE_FILE: // do nothing
+                       case YAFFS_OBJECT_TYPE_DIRECTORY: // do nothing
+                       case YAFFS_OBJECT_TYPE_UNKNOWN:
+               }
+
+               yaffs_UpdateObjectHeader(in,name);
+
+       }
+       
+       return in;
+}
+
+yaffs_Object *yaffs_MknodFile(yaffs_Object *parent,const char *name, __u32 mode, __u32 uid, __u32 gid)
+{
+       return yaffs_MknodObject(YAFFS_OBJECT_TYPE_FILE,parent,name,mode,uid,gid,NULL,NULL);
+}
+
+yaffs_Object *yaffs_MknodDirectory(yaffs_Object *parent,const char *name, __u32 mode, __u32 uid, __u32 gid)
+{
+       return yaffs_MknodObject(YAFFS_OBJECT_TYPE_DIRECTORY,parent,name,mode,uid,gid,NULL,NULL);
+}
+
+yaffs_Object *yaffs_MknodSymLink(yaffs_Object *parent,const char *name, __u32 mode, __u32 uid, __u32 gid,const char *alias)
+{
+       return yaffs_MknodObject(YAFFS_OBJECT_TYPE_SYMLINK,parent,name,mode,uid,gid,NULL,alias);
+}
+
+// NB yaffs_Link returns the object id of the equivalent object.
+yaffs_Object *yaffs_Link(yaffs_Object *parent, const char *name, yaffs_Object *equivalentObject)
+{
+       // Get the real object in case we were fed a hard link as an equivalent object
+       equivalentObject = yaffs_GetEquivalentObject(equivalentObject);
+       
+       if(yaffs_MknodObject(YAFFS_OBJECT_TYPE_HARDLINK,parent,name,0,0,0,equivalentObject,NULL))
+       {
+               return equivalentObject;
+       }
+       else
+       {
+               return NULL;
+       }
+       
+}
+
+
+static int yaffs_ChangeObjectName(yaffs_Object *obj, yaffs_Object *newDir, const char *newName)
+{
+       //yaffs_Device *dev = obj->myDev;
+
+       if(newDir == NULL)
+       {
+               newDir = obj->parent; // use the old directory
+       }
+       
+       // Only proceed if the new name does not exist and
+       // if we're putting it into a directory.
+       if(!yaffs_FindObjectByName(newDir,newName) &&
+           newDir->variantType == YAFFS_OBJECT_TYPE_DIRECTORY)
+       {
+               obj->sum = yaffs_CalcNameSum(newName);
+               obj->dirty = 1;
+               yaffs_AddObjectToDirectory(newDir,obj);
+               
+               return yaffs_UpdateObjectHeader(obj,newName);   
+       }
+       
+       return YAFFS_FAIL;
+}
+
+int yaffs_RenameObject(yaffs_Object *oldDir, const char *oldName, yaffs_Object *newDir, const char *newName)
+{
+       yaffs_Object *obj;
+       
+       obj = yaffs_FindObjectByName(oldDir,oldName);
+       if(obj && obj->renameAllowed)
+       {
+               return yaffs_ChangeObjectName(obj,newDir,newName);
+       }
+       return YAFFS_FAIL;
+}
+
+
+
+static int yaffs_CheckObjectHashSanity(yaffs_Device *dev)
+{
+       // Scan the buckets and check that the lists 
+       // have as many members as the count says there are
+       int bucket;
+       int countEm;
+       struct list_head *j;
+       int ok = YAFFS_OK;
+       
+       for(bucket = 0; bucket < YAFFS_NOBJECT_BUCKETS; bucket++)
+       {
+               countEm = 0;
+               
+               list_for_each(j,&dev->objectBucket[bucket].list)
+               {
+                       countEm++;
+               }
+               
+               if(countEm != dev->objectBucket[bucket].count)
+               {
+                       YALERT("Inode hash inconsistency");
+                       ok = YAFFS_FAIL;
+               }
+       }
+
+       return ok;
+}
+
+void yaffs_ObjectTest(yaffs_Device *dev)
+{
+       yaffs_Object *in[1000];
+       int inNo[1000];
+       yaffs_Object *inold[1000];
+       int i;
+       int j;
+       
+       memset(in,0,1000*sizeof(yaffs_Object *));
+       memset(inold,0,1000*sizeof(yaffs_Object *));
+       
+       yaffs_CheckObjectHashSanity(dev);
+       
+       for(j = 0; j < 10; j++)
+       {
+               T(("%d\n",j));
+               
+               for(i = 0; i < 1000; i++)
+               {
+                       in[i] = yaffs_CreateNewObject(dev,-1,YAFFS_OBJECT_TYPE_FILE);
+                       if(!in[i])
+                       {
+                               YINFO("No more inodes");
+                       }
+                       else
+                       {
+                               inNo[i] = in[i]->objectId;
+                       }
+               }
+               
+               for(i = 0; i < 1000; i++)
+               {
+                       if(yaffs_FindObjectByNumber(dev,inNo[i]) != in[i])
+                       {
+                               T(("Differnce in look up test\n"));
+                       }
+                       else
+                       {
+                               // T(("Look up ok\n"));
+                       }
+               }
+               
+               yaffs_CheckObjectHashSanity(dev);
+       
+               for(i = 0; i < 1000; i+=3)
+               {
+                       yaffs_FreeObject(in[i]);        
+                       in[i] = NULL;
+               }
+               
+       
+               yaffs_CheckObjectHashSanity(dev);
+       }
+               
+}
+
+
+
+/////////////////////////// Block Management and Page Allocation ///////////////////
+
+
+static void yaffs_InitialiseBlocks(yaffs_Device *dev)
+{
+       dev->blockInfo = YMALLOC(dev->nBlocks * sizeof(yaffs_BlockInfo));
+       memset(dev->blockInfo,0,dev->nBlocks * sizeof(yaffs_BlockInfo));
+       dev->allocationBlock = -1; // force it to get a new one
+}
+
+static void yaffs_DeinitialiseBlocks(yaffs_Device *dev)
+{
+       YFREE(dev->blockInfo);
+}
+
+// FindDiretiestBlock is used to select the dirtiest block (or close enough)
+// for garbage collection.
+
+static int yaffs_FindDirtiestBlock(yaffs_Device *dev)
+{
+
+       int b = dev->currentDirtyChecker;
+       
+       int i;
+       int dirtiest = -1;
+       int pagesInUse = 100; // silly big number
+       
+       for(i = dev->startBlock; i <= dev->endBlock && pagesInUse > 2 ; i++)
+       {
+               b++;
+               if (b > dev->endBlock)
+               {
+                       b =  dev->startBlock;
+               }
+               
+               if(dev->blockInfo[b].blockState == YAFFS_BLOCK_STATE_FULL &&
+                  (dev->blockInfo)[b].pagesInUse < pagesInUse)
+               {
+                       dirtiest = b;
+                       pagesInUse = (dev->blockInfo)[b].pagesInUse;
+               }
+       }
+       
+       dev->currentDirtyChecker = b;
+       
+       return dirtiest;
+}
+
+
+static int yaffs_FindBlockForAllocation(yaffs_Device *dev,int useReserve)
+{
+       int i;
+       
+       if(useReserve && dev->nErasedBlocks < 1)
+       {
+               // Hoosterman we've got a problem.
+               // Can't get space to gc
+               return -1;
+       }
+       else if(!useReserve && dev->nErasedBlocks <= YAFFS_RESERVED_BLOCKS)
+       {
+               // We are not in GC, so we hold some in reserve so we can get
+               // a gc done.
+       }
+       
+       // Find an empty block.
+       
+       for(i = dev->startBlock; i <= dev->endBlock; i++)
+       {
+                       
+               if(dev->blockInfo[i].blockState == YAFFS_BLOCK_STATE_EMPTY)
+               {
+                       dev->blockInfo[i].blockState = YAFFS_BLOCK_STATE_ALLOCATING;
+                       dev->nErasedBlocks--;
+                       if(dev->nErasedBlocks <= YAFFS_RESERVED_BLOCKS)
+                       {
+                               dev->garbageCollectionRequired = 1;
+                       }
+                       
+                       return i;
+               }
+       }
+       
+       return -1;      
+}
+
+
+static void yaffs_BlockBecameDirty(yaffs_Device *dev,int blockNo)
+{
+       yaffs_BlockInfo *bi = &dev->blockInfo[blockNo];
+       
+       // Mark as dirty, erase it and mark as clean.
+       bi->blockState = YAFFS_BLOCK_STATE_DIRTY;
+       yaffs_EraseBlockInNAND(dev,blockNo);
+       bi->blockState = YAFFS_BLOCK_STATE_EMPTY;
+       dev->nErasedBlocks++;
+       bi->pagesInUse = 0;
+       bi->pageBits = 0;
+       
+       T(("Erased block %d\n",blockNo));
+}
+
+
+static int yaffs_AllocateChunk(yaffs_Device *dev,int useReserve)
+{
+       int retVal;
+       
+       if(dev->allocationBlock < 0)
+       {
+               // Get next block to allocate off
+               dev->allocationBlock = yaffs_FindBlockForAllocation(dev,useReserve);
+               dev->allocationPage = 0;
+       }
+       
+       // Next page please....
+       if(dev->allocationBlock >= 0)
+       {
+               retVal = (dev->allocationBlock * YAFFS_CHUNKS_PER_BLOCK) + 
+                                 dev->allocationPage;
+               dev->blockInfo[dev->allocationBlock].pagesInUse++;
+               dev->blockInfo[dev->allocationBlock].pageBits |= 
+                               (1 << (dev->allocationPage));
+
+               dev->allocationPage++;
+               
+               dev->nFreeChunks--;
+               
+               // If the block is full set the state to full
+               if(dev->allocationPage >= YAFFS_CHUNKS_PER_BLOCK)
+               {
+                       dev->blockInfo[dev->allocationBlock].blockState = YAFFS_BLOCK_STATE_FULL;
+                       dev->allocationBlock = -1;
+               }
+
+#ifdef YAFFS_PARANOID
+               if(yaffs_CheckChunkErased(retVal) == YAFFS_FAIL)
+               {
+                       T(("..................Trying to allocate non-erased page %d\n",retVal));
+               }
+#endif         
+               return retVal;
+               
+       }
+       T(("!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!\n"));
+
+       return -1;      
+}
+
+
+int  yaffs_GarbageCollectBlock(yaffs_Device *dev,int block)
+{
+       int oldChunk;
+       int newChunk;
+       __u32 mask;
+       
+       
+       yaffs_Spare spare;
+       yaffs_Tags  tags;
+               __u8  buffer[YAFFS_BYTES_PER_CHUNK];
+       
+       yaffs_BlockInfo *bi = &dev->blockInfo[block];
+       
+       yaffs_Object *object;
+
+       T(("Collecting block %d n %d bits %x\n",block, bi->pagesInUse, bi->pageBits));  
+       
+       for(mask = 1,oldChunk = block * YAFFS_CHUNKS_PER_BLOCK; 
+           mask && bi->pageBits;
+           mask <<= 1, oldChunk++ )
+       {
+               if(bi->pageBits & mask)
+               {
+                       
+                       // This page is in use and needs to be copied off
+                       
+                       T(("copying page %x from %d to %d\n",mask,oldChunk,newChunk));
+                       
+                       yaffs_ReadChunkFromNAND(dev,oldChunk,buffer, &spare);
+                       
+                       yaffs_GetTagsFromSpare(&spare,&tags);
+                       tags.serialNumber++;
+                       yaffs_LoadTagsIntoSpare(&spare,&tags);
+
+#if 0
+                       newChunk = yaffs_AllocatePage(dev,1);
+                       if(newChunk < 0)
+                       {
+                               return YAFFS_FAIL;
+                       }
+
+                       yaffs_WriteChunkToNAND(dev,newChunk, buffer, &spare);
+
+#else
+                       newChunk = yaffs_WriteNewChunkToNAND(dev, buffer, &spare,1);
+#endif
+                       if(newChunk < 0)
+                       {
+                               return YAFFS_FAIL;
+                       }
+
+                       object = yaffs_FindObjectByNumber(dev,tags.objectId);
+                       
+                       // Ok, now fix up the Tnodes etc.
+                       
+                       if(tags.chunkId == 0)
+                       {
+                               // It's a header
+                               object->chunkId = newChunk;
+                       }
+                       else
+                       {
+                               // It's a data chunk
+                               yaffs_PutChunkIntoFile(object, tags.chunkId, newChunk);
+
+                       }
+                       
+                       yaffs_DeleteChunk(dev,oldChunk);                        
+                       
+               }
+       }
+
+       return YAFFS_OK;
+}
+
+int yaffs_CheckGarbageCollection(yaffs_Device *dev)
+{
+       int block;
+       
+       if(dev->garbageCollectionRequired)
+       {
+               dev->garbageCollectionRequired = 0;
+               block = yaffs_FindDirtiestBlock(dev);
+               if(block >= 0)
+               {
+                       return yaffs_GarbageCollectBlock(dev,block);
+               }       
+               else
+               {
+                       return YAFFS_FAIL;
+               }
+       }
+
+       return YAFFS_OK;
+}
+
+
+//////////////////////////// TAGS ///////////////////////////////////////
+
+static void yaffs_LoadTagsIntoSpare(yaffs_Spare *sparePtr, yaffs_Tags *tagsPtr)
+{
+       yaffs_TagsUnion *tu = (yaffs_TagsUnion *)tagsPtr;
+       
+       yaffs_CalcTagsECC(tagsPtr);
+       
+       sparePtr->tagByte0 = tu->asBytes[0];
+       sparePtr->tagByte1 = tu->asBytes[1];
+       sparePtr->tagByte2 = tu->asBytes[2];
+       sparePtr->tagByte3 = tu->asBytes[3];
+       sparePtr->tagByte4 = tu->asBytes[4];
+       sparePtr->tagByte5 = tu->asBytes[5];
+       sparePtr->tagByte6 = tu->asBytes[6];
+       sparePtr->tagByte7 = tu->asBytes[7];
+}
+
+static void yaffs_GetTagsFromSpare(yaffs_Spare *sparePtr,yaffs_Tags *tagsPtr)
+{
+       yaffs_TagsUnion *tu = (yaffs_TagsUnion *)tagsPtr;
+
+       tu->asBytes[0]= sparePtr->tagByte0;
+       tu->asBytes[1]= sparePtr->tagByte1;
+       tu->asBytes[2]= sparePtr->tagByte2;
+       tu->asBytes[3]= sparePtr->tagByte3;
+       tu->asBytes[4]= sparePtr->tagByte4;
+       tu->asBytes[5]= sparePtr->tagByte5;
+       tu->asBytes[6]= sparePtr->tagByte6;
+       tu->asBytes[7]= sparePtr->tagByte7;
+       
+       // Todo Check ECC on tags
+}
+
+static void yaffs_SpareInitialise(yaffs_Spare *spare)
+{
+       memset(spare,0xFF,sizeof(yaffs_Spare));
+}
+
+static int yaffs_ReadChunkTagsFromNAND(yaffs_Device *dev,int chunkInNAND, yaffs_Tags *tags)
+{
+       if(tags)
+       {
+               yaffs_Spare spare;
+               if(yaffs_ReadChunkFromNAND(dev,chunkInNAND,NULL,&spare) == YAFFS_OK)
+               {
+                       yaffs_GetTagsFromSpare(&spare,tags);
+                       return YAFFS_OK;
+               }
+               else
+               {
+                       return YAFFS_FAIL;
+               }
+       }
+       
+       return YAFFS_OK;
+}
+
+static int yaffs_WriteChunkWithTagsToNAND(yaffs_Device *dev,int chunkInNAND, const __u8 *buffer, yaffs_Tags *tags)
+{
+       // NB There must be tags, data is optional
+       // If there is data, then an ECC is calculated on it.
+       
+       yaffs_Spare spare;
+       
+       if(!tags)
+       {
+               return YAFFS_FAIL;
+       }
+       
+       yaffs_SpareInitialise(&spare);
+       
+
+       if(buffer)
+       {
+               yaffs_CalcECC(buffer,&spare);
+       }
+       
+       yaffs_LoadTagsIntoSpare(&spare,tags);
+       
+       return yaffs_WriteChunkToNAND(dev,chunkInNAND,buffer,&spare);
+       
+}
+
+static int yaffs_WriteNewChunkWithTagsToNAND(yaffs_Device *dev, const __u8 *buffer, yaffs_Tags *tags, int useReserve)
+{
+       // NB There must be tags, data is optional
+       // If there is data, then an ECC is calculated on it.
+       
+       yaffs_Spare spare;
+       
+       if(!tags)
+       {
+               return YAFFS_FAIL;
+       }
+       
+       yaffs_SpareInitialise(&spare);
+       
+
+       if(buffer)
+       {
+               yaffs_CalcECC(buffer,&spare);
+       }
+       
+       yaffs_LoadTagsIntoSpare(&spare,tags);
+       
+       return yaffs_WriteNewChunkToNAND(dev,buffer,&spare,useReserve);
+       
+}
+
+
+
+
+int yaffs_FindChunkInFile(yaffs_Object *in,int chunkInInode,yaffs_Tags *tags)
+{
+       //Get the Tnode, then get the level 0 offset chunk offset
+    yaffs_Tnode *tn;     
+    int theChunk = -1;
+    yaffs_Tags localTags;
+    int i;
+    int found = 0;
+    yaffs_Device *dev = in->myDev;
+    
+    
+    if(!tags)
+    {
+       // Passed a NULL, so use our own tags space
+       tags = &localTags;
+    }
+    
+    tn = yaffs_FindLevel0Tnode(dev,&in->variant.fileVariant, chunkInInode);
+    
+    if(tn)
+    {
+               theChunk = tn->level0[chunkInInode & YAFFS_TNODES_LEVEL0_MASK] << dev->chunkGroupBits;
+
+               // Now we need to do the shifting etc and search for it
+               for(i = 0,found = 0; i < dev->chunkGroupSize && !found; i++)
+               {
+                       yaffs_ReadChunkTagsFromNAND(dev,theChunk,tags);
+                       if(tags->chunkId == chunkInInode &&
+                       tags->objectId == in->objectId)
+                       {
+                               // found it;
+                               found = 1;
+                       }
+                       else
+                       {
+                               theChunk++;
+                       }
+               }
+    }
+    return found ? theChunk : -1;
+}
+
+int yaffs_FindAndDeleteChunkInFile(yaffs_Object *in,int chunkInInode,yaffs_Tags *tags)
+{
+       //Get the Tnode, then get the level 0 offset chunk offset
+    yaffs_Tnode *tn;     
+    int theChunk = -1;
+    yaffs_Tags localTags;
+    int i;
+    int found = 0;
+    yaffs_Device *dev = in->myDev;
+    
+    if(!tags)
+    {
+       // Passed a NULL, so use our own tags space
+       tags = &localTags;
+    }
+    
+    tn = yaffs_FindLevel0Tnode(dev,&in->variant.fileVariant, chunkInInode);
+    
+    if(tn)
+    {
+    
+               theChunk = tn->level0[chunkInInode & YAFFS_TNODES_LEVEL0_MASK] << dev->chunkGroupBits;
+    
+               // Now we need to do the shifting etc and search for it
+               for(i = 0,found = 0; i < dev->chunkGroupSize && !found; i++)
+               {
+                       yaffs_ReadChunkTagsFromNAND(dev,theChunk,tags);
+                       if(tags->chunkId == chunkInInode &&
+                       tags->objectId == in->objectId)
+                       {
+                               // found it;
+                               found = 1;
+                       }
+                       else
+                       {
+                               theChunk++;
+                       }
+               }
+    
+               // Delete the entry in the filestructure
+               if(found)
+               {
+                       tn->level0[chunkInInode & YAFFS_TNODES_LEVEL0_MASK] = 0;
+               }
+    }
+    else
+    {
+       T(("No level 0 found for %d\n", chunkInInode));
+    }
+    
+    if(!found)
+    {
+       T(("Could not find %d to delete\n",chunkInInode));
+    }
+    return found ? theChunk : -1;
+}
+
+
+#if YAFFS_PARANOID
+
+static int yaffs_CheckFileSanity(yaffs_Object *in)
+{
+       int chunk;
+       int nChunks;
+       int fSize;
+       int failed = 0;
+       int objId;
+       yaffs_Tnode *tn;
+    yaffs_Tags localTags;
+    yaffs_Tags *tags = &localTags;
+    int theChunk;
+    
+       
+       if(in->variantType != YAFFS_OBJECT_TYPE_FILE)
+       {
+               T(("Object not a file\n"));
+               return YAFFS_FAIL;
+       }
+       
+       objId = in->objectId;
+       fSize  = in->variant.fileVariant.fileSize;
+       nChunks = (fSize + YAFFS_BYTES_PER_CHUNK -1)/YAFFS_BYTES_PER_CHUNK;
+       
+       for(chunk = 1; chunk <= nChunks; chunk++)
+       {
+               tn = yaffs_FindLevel0Tnode(&in->variant.fileVariant, chunk);
+    
+               if(tn)
+               {
+    
+                       theChunk = tn->level0[chunk & YAFFS_TNODES_LEVEL0_MASK] << dev->chunkGroupBits;
+    
+
+                               yaffs_ReadChunkTagsFromNAND(theChunk,tags);
+                               if(tags->chunkId == chunk &&
+                               tags->objectId == in->objectId)
+                               {
+                                       // found it;
+                                       
+                               }
+                               else
+                               {
+                                       //T(("File problem file [%d,%d] NAND %d  tags[%d,%d]\n",
+                                       //              objId,chunk,theChunk,tags->chunkId,tags->objectId);
+                                                       
+                                       failed = 1;
+                                                               
+                               }
+    
+               }
+               else
+               {
+                       T(("No level 0 found for %d\n", chunk));
+               }
+       }
+       
+       return failed ? YAFFS_FAIL : YAFFS_OK;
+}
+
+#endif
+
+static int yaffs_PutChunkIntoFile(yaffs_Object *in,int chunkInInode, int chunkInNAND)
+{
+       yaffs_Tnode *tn;
+       yaffs_Device *dev = in->myDev;
+       
+       tn = yaffs_AddOrFindLevel0Tnode(dev,&in->variant.fileVariant, chunkInInode);
+       tn->level0[chunkInInode & YAFFS_TNODES_LEVEL0_MASK] = chunkInNAND;
+       return YAFFS_OK;
+}
+
+
+
+int yaffs_ReadChunkDataFromObject(yaffs_Object *in,int chunkInInode, __u8 *buffer)
+{
+    int chunkInNAND = yaffs_FindChunkInFile(in,chunkInInode,NULL);
+    
+    if(chunkInNAND >= 0)
+    {
+               return yaffs_ReadChunkFromNAND(in->myDev,chunkInNAND,buffer,NULL);
+       }
+       else
+       {
+               return 0;
+       }
+
+}
+
+
+static void yaffs_DeleteChunk(yaffs_Device *dev,int chunkId)
+{
+       int block = chunkId / YAFFS_CHUNKS_PER_BLOCK;
+       int page = chunkId % YAFFS_CHUNKS_PER_BLOCK;
+       yaffs_Tags tags;
+       
+       // Mark the deleted NAND page as deleted
+       tags.chunkId = 0;
+       tags.objectId = 0;
+       tags.byteCount = 0;
+       tags.ecc = 0;
+       
+       yaffs_WriteChunkWithTagsToNAND(dev,chunkId,NULL,&tags); 
+                       
+       
+       // Pull out of the management area.
+       if(     dev->blockInfo[block].blockState == YAFFS_BLOCK_STATE_ALLOCATING ||
+           dev->blockInfo[block].blockState == YAFFS_BLOCK_STATE_FULL)
+       {
+               dev->nFreeChunks++;
+
+               dev->blockInfo[block].pageBits &= ~(1 << page);
+               dev->blockInfo[block].pagesInUse--;
+               
+               if(     dev->blockInfo[block].pagesInUse == 0 &&
+           dev->blockInfo[block].blockState == YAFFS_BLOCK_STATE_FULL)
+           {
+               yaffs_BlockBecameDirty(dev,block);
+           }
+
+       }
+       else
+       {
+               T(("Bad news deteing chunk %d\n",chunkId));
+       }
+       
+}
+
+
+
+
+int yaffs_WriteChunkDataToObject(yaffs_Object *in,int chunkInInode, const __u8 *buffer,int nBytes,int useReserve)
+{
+       // Find old chunk Need to do this to get serial number
+       // Write new one and patch into tree.
+       // Invalidate old tags.
+
+    int prevChunkId;
+    yaffs_Tags prevTags;
+    
+    int newChunkId;
+    yaffs_Tags newTags;
+
+    yaffs_Device *dev = in->myDev;    
+
+       yaffs_CheckGarbageCollection(dev);
+
+       // Get the previous chunk at this location in the file if it exists
+    prevChunkId  = yaffs_FindChunkInFile(in,chunkInInode,&prevTags);
+    
+    // Set up new tags
+       newTags.chunkId = chunkInInode;
+       newTags.objectId = in->objectId;
+       newTags.serialNumber = (prevChunkId >= 0) ? prevTags.serialNumber + 1 : 1;
+       newTags.byteCount = nBytes;
+       newTags.unusedStuff = 0xFFFFFFFF;
+               
+       yaffs_CalcTagsECC(&newTags);
+
+    
+ #if 0
+    // Create new chunk in NAND
+    newChunkId = yaffs_AllocatePage(dev,useReserve);
+    
+    if(newChunkId >= 0)
+    {
+               
+
+               yaffs_WriteChunkWithTagsToNAND(dev,newChunkId,buffer,&newTags);
+               
+               yaffs_PutChunkIntoFile(in,chunkInInode,newChunkId);
+               
+               
+               if(prevChunkId >= 0)
+               {
+                       yaffs_DeleteChunk(dev,prevChunkId);
+       
+               }
+               
+               yaffs_CheckFileSanity(in);
+               
+               return newChunkId;
+    }
+
+     
+    return -1;
+#else
+
+       newChunkId = yaffs_WriteNewChunkWithTagsToNAND(dev,buffer,&newTags,useReserve);
+       if(newChunkId >= 0)
+       {
+               yaffs_PutChunkIntoFile(in,chunkInInode,newChunkId);
+               
+               
+               if(prevChunkId >= 0)
+               {
+                       yaffs_DeleteChunk(dev,prevChunkId);
+       
+               }
+               
+               yaffs_CheckFileSanity(in);
+       }
+       return newChunkId;
+
+#endif
+
+
+
+}
+
+
+// UpdateObjectHeader updates the header on NAND for an object.
+// If name is not NULL, then that new name is used.
+//
+int yaffs_UpdateObjectHeader(yaffs_Object *in,const char *name)
+{
+
+       yaffs_Device *dev = in->myDev;
+       
+    int prevChunkId;
+    
+    int newChunkId;
+    yaffs_Tags newTags;
+    __u8 bufferNew[YAFFS_BYTES_PER_CHUNK];
+    __u8 bufferOld[YAFFS_BYTES_PER_CHUNK];
+    
+    yaffs_ObjectHeader *oh = (yaffs_ObjectHeader *)bufferNew;
+    yaffs_ObjectHeader *ohOld = (yaffs_ObjectHeader *)bufferOld;
+    
+    if(!in->fake)
+    {
+  
+               yaffs_CheckGarbageCollection(dev);              
+    
+               memset(bufferNew,0xFF,YAFFS_BYTES_PER_CHUNK);
+    
+               prevChunkId = in->chunkId;
+    
+               if(prevChunkId >= 0)
+               {
+                       yaffs_ReadChunkFromNAND(dev,prevChunkId,bufferOld,NULL);        
+               }
+
+               // Header data
+               oh->type = in->variantType;
+       
+               oh->st_mode = in->st_mode;
+               oh->st_uid = in->st_uid;
+               oh->st_gid = in->st_gid;
+               oh->st_atime = in->st_atime;
+               oh->st_mtime = in->st_mtime;
+               oh->st_ctime = in->st_ctime;
+       
+               oh->parentObjectId = in->parent->objectId;
+               oh->sum = in->sum;
+               if(name && *name)
+               {
+                       memset(oh->name,0,YAFFS_MAX_NAME_LENGTH + 1);
+                       strncpy(oh->name,name,YAFFS_MAX_NAME_LENGTH);
+               }
+               else
+               {       
+                       memcpy(oh->name, ohOld->name,YAFFS_MAX_NAME_LENGTH + 1);
+               }
+       
+               switch(in->variantType)
+               {
+                       case YAFFS_OBJECT_TYPE_UNKNOWN:         // Todo got a problem
+                               break;
+                       case YAFFS_OBJECT_TYPE_FILE:
+                               oh->fileSize = in->variant.fileVariant.fileSize;
+                               break;
+                       case YAFFS_OBJECT_TYPE_HARDLINK:
+                               oh->equivalentObjectId = in->variant.hardLinkVariant.equivalentObjectId;
+                               break;
+                       case YAFFS_OBJECT_TYPE_DIRECTORY:       // Do nothing
+                               break;
+                       case YAFFS_OBJECT_TYPE_SYMLINK:
+                               strncpy(oh->alias,in->variant.symLinkVariant.alias,YAFFS_MAX_ALIAS_LENGTH);
+                               oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
+                               break;
+               }
+
+               // Tags
+               in->serial++;
+               newTags.chunkId = 0;
+               newTags.objectId = in->objectId;
+               newTags.serialNumber = in->serial;
+               newTags.byteCount =   0xFFFFFFFF;
+               newTags.unusedStuff = 0xFFFFFFFF;
+       
+               yaffs_CalcTagsECC(&newTags);
+       
+    
+    
+#if 0
+               // Create new chunk in NAND
+               newChunkId = yaffs_AllocatePage(dev,1);
+    
+               if(newChunkId >= 0)
+               {
+
+                       yaffs_WriteChunkWithTagsToNAND(dev,newChunkId,bufferNew,&newTags);
+               
+                       in->chunkId = newChunkId;               
+               
+                       if(prevChunkId >= 0)
+                       {
+                               yaffs_DeleteChunk(dev,prevChunkId);
+                       }
+               
+                       in->dirty = 0;
+                       return newChunkId;
+               }
+    
+               return -1;
+#else
+               // Create new chunk in NAND
+               newChunkId = yaffs_WriteNewChunkWithTagsToNAND(dev,bufferNew,&newTags,1);
+    
+               if(newChunkId >= 0)
+               {
+               
+                       in->chunkId = newChunkId;               
+               
+                       if(prevChunkId >= 0)
+                       {
+                               yaffs_DeleteChunk(dev,prevChunkId);
+                       }
+               
+                       in->dirty = 0;
+               }
+               
+               return newChunkId;
+
+#endif
+    }
+    return 0;
+}
+
+
+
+///////////////////////// File read/write ///////////////////////////////
+// Read and write have very similar structures.
+// In general the read/write has three parts to it
+// * An incomplete chunk to start with (if the read/write is not chunk-aligned)
+// * Some complete chunks
+// * An incomplete chunk to end off with
+//
+// Curve-balls: the first chunk might also be the last chunk.
+
+int yaffs_ReadDataFromFile(yaffs_Object *in, __u8 * buffer, __u32 offset, int nBytes)
+{
+       
+//     yaffs_Device *dev = in->myDev;
+       
+       __u8 localBuffer[YAFFS_BYTES_PER_CHUNK];
+       
+       int chunk;
+       int start;
+       int nToCopy;
+       int n = nBytes;
+       int nDone = 0;
+       
+       while(n > 0)
+       {
+               chunk = offset / YAFFS_BYTES_PER_CHUNK + 1; // The first chunk is 1
+               start = offset % YAFFS_BYTES_PER_CHUNK;
+
+               // OK now check for the curveball where the start and end are in
+               // the same chunk.      
+               if(     (start + n) < YAFFS_BYTES_PER_CHUNK)
+               {
+                       nToCopy = n;
+               }
+               else
+               {
+                       nToCopy = YAFFS_BYTES_PER_CHUNK - start;
+               }
+       
+               if(nToCopy != YAFFS_BYTES_PER_CHUNK)
+               {
+                       // An incomplete start or end chunk (or maybe both start and end chunk)
+                       // Read into the local buffer then copy...
+               
+                       yaffs_ReadChunkDataFromObject(in,chunk,localBuffer);            
+                       memcpy(buffer,&localBuffer[start],nToCopy);
+               }
+               else
+               {
+                       // A full chunk. Read directly into the supplied buffer.
+                       yaffs_ReadChunkDataFromObject(in,chunk,buffer);
+               }
+               
+               n -= nToCopy;
+               offset += nToCopy;
+               buffer += nToCopy;
+               nDone += nToCopy;
+               
+       }
+       
+       return nDone;
+}
+
+
+int yaffs_WriteDataToFile(yaffs_Object *in,const __u8 * buffer, __u32 offset, int nBytes)
+{      
+       __u8 localBuffer[YAFFS_BYTES_PER_CHUNK];
+       
+       int chunk;
+       int start;
+       int nToCopy;
+       int n = nBytes;
+       int nDone = 0;
+       int nToWriteBack;
+       int endOfWrite = offset+nBytes;
+       int chunkWritten = 0;
+       
+       while(n > 0 && chunkWritten >= 0)
+       {
+               chunk = offset / YAFFS_BYTES_PER_CHUNK + 1;
+               start = offset % YAFFS_BYTES_PER_CHUNK;
+               
+
+               // OK now check for the curveball where the start and end are in
+               // the same chunk.
+               if(     (start + n) < YAFFS_BYTES_PER_CHUNK)
+               {
+                       nToCopy = n;
+                       nToWriteBack = (start + n);
+               }
+               else
+               {
+                       nToCopy = YAFFS_BYTES_PER_CHUNK - start;
+                       nToWriteBack = YAFFS_BYTES_PER_CHUNK;
+               }
+       
+               if(nToCopy != YAFFS_BYTES_PER_CHUNK)
+               {
+                       // An incomplete start or end chunk (or maybe both start and end chunk)
+                       // Read into the local buffer then copy, then copy over and write back.
+               
+                       yaffs_ReadChunkDataFromObject(in,chunk,localBuffer);
+                               
+                       memcpy(&localBuffer[start],buffer,nToCopy);
+                       
+                       chunkWritten = yaffs_WriteChunkDataToObject(in,chunk,localBuffer,nToWriteBack,0);
+                       
+                       T(("Write with readback to chunk %d %d\n",chunk,chunkWritten));
+                       
+               }
+               else
+               {
+                       // A full chunk. Write directly from the supplied buffer.
+                       chunkWritten = yaffs_WriteChunkDataToObject(in,chunk,buffer,YAFFS_BYTES_PER_CHUNK,0);
+                       T(("Write to chunk %d %d\n",chunk,chunkWritten));
+               }
+               
+               if(chunkWritten >= 0)
+               {
+                       n -= nToCopy;
+                       offset += nToCopy;
+                       buffer += nToCopy;
+                       nDone += nToCopy;
+               }
+               
+       }
+       
+       // Update file object
+       
+       if(endOfWrite > in->variant.fileVariant.fileSize)
+       {
+               in->variant.fileVariant.fileSize = endOfWrite;
+       }
+       
+       in->dirty = 1;
+       in->st_mtime = CURRENT_TIME;
+       
+       return nDone;
+}
+
+
+int yaffs_ResizeFile(yaffs_Object *in, int newSize)
+{
+       int i;
+       int chunkId;
+       int oldFileSize = in->variant.fileVariant.fileSize;
+       int sizeOfLastChunk = newSize % YAFFS_BYTES_PER_CHUNK;
+       
+       yaffs_Device *dev = in->myDev;
+       
+       __u8 localBuffer[YAFFS_BYTES_PER_CHUNK];
+       
+       if(in->variantType != YAFFS_OBJECT_TYPE_FILE)
+       {
+               return yaffs_GetFileSize(in);
+       }
+       
+       if(newSize < oldFileSize)
+       {
+               
+               int lastDel = 1 + oldFileSize/YAFFS_BYTES_PER_CHUNK;
+               
+               int startDel = 1 + (newSize + YAFFS_BYTES_PER_CHUNK - 1)/
+                                                       YAFFS_BYTES_PER_CHUNK;
+
+               for(i = startDel; i <= lastDel; i++)
+               {
+                       // NB this could be optimised somewhat,
+                       // eg. could retrieve the tags and write them without
+                       // using yaffs_DeleteChunk
+                       chunkId = yaffs_FindAndDeleteChunkInFile(in,i,NULL);
+                       if(chunkId < 0 || chunkId >= (dev->endBlock * 32))
+                       {
+                               T(("Found daft chunkId %d for %d\n",chunkId,i));
+                       }
+                       else
+                       {
+                               yaffs_DeleteChunk(dev,chunkId);
+                       }
+               }
+               
+               
+               if(sizeOfLastChunk != 0)
+               {
+                       int lastChunk = 1+ newSize/YAFFS_BYTES_PER_CHUNK;
+                       
+                       // Got to read and rewrite the last chunk with its new size.
+                       yaffs_ReadChunkDataFromObject(in,lastChunk,localBuffer);
+                       
+                       yaffs_WriteChunkDataToObject(in,lastChunk,localBuffer,sizeOfLastChunk,1);
+                               
+               }
+               
+               in->variant.fileVariant.fileSize = newSize;
+               
+               yaffs_PruneFileStructure(dev,&in->variant.fileVariant);
+               
+               return newSize;
+               
+       }
+       else
+       {
+               return oldFileSize;
+       }
+}
+
+
+loff_t yaffs_GetFileSize(yaffs_Object *obj)
+{
+       obj = yaffs_GetEquivalentObject(obj);
+       
+       switch(obj->variantType)
+       {
+               case YAFFS_OBJECT_TYPE_FILE: 
+                       return obj->variant.fileVariant.fileSize;
+               case YAFFS_OBJECT_TYPE_SYMLINK:
+                       return strlen(obj->variant.symLinkVariant.alias);
+               default:
+                       return 0;
+       }
+}
+
+
+
+// yaffs_FlushFile() updates the file's
+// objectId in NAND
+
+int yaffs_FlushFile(yaffs_Object *in)
+{
+       int retVal;
+       if(in->dirty)
+       {
+               retVal = yaffs_UpdateObjectHeader(in,NULL);
+       }
+       else
+       {
+               retVal = YAFFS_OK;
+       }
+       
+       return retVal;
+       
+}
+
+
+static int yaffs_DoGenericObjectDeletion(yaffs_Object *in)
+{
+       yaffs_RemoveObjectFromDirectory(in);
+       yaffs_DeleteChunk(in->myDev,in->chunkId);
+       yaffs_FreeObject(in);
+       return YAFFS_OK;
+
+}
+
+// yaffs_DeleteFile deletes the whole file data
+// and the inode associated with the file.
+// It does not delete the links associated with the file.
+static int yaffs_DeleteFile(yaffs_Object *in)
+{
+       // Delete the file data & tnodes
+       yaffs_ResizeFile(in,0);
+       yaffs_FreeTnode(in->myDev,in->variant.fileVariant.top);
+       
+       return  yaffs_DoGenericObjectDeletion(in);
+}
+
+static int yaffs_DeleteDirectory(yaffs_Object *in)
+{
+       //First check that the directory is empty.
+       if(list_empty(&in->variant.directoryVariant.children))
+       {
+               return  yaffs_DoGenericObjectDeletion(in);
+       }
+       
+       return YAFFS_FAIL;
+       
+}
+
+static int yaffs_DeleteSymLink(yaffs_Object *in)
+{
+       YFREE(in->variant.symLinkVariant.alias);
+
+       return  yaffs_DoGenericObjectDeletion(in);
+}
+
+static int yaffs_DeleteHardLink(yaffs_Object *in)
+{
+       // remove this hardlink from the list assocaited with the equivalent
+       // object
+       list_del(&in->hardLinks);
+       return  yaffs_DoGenericObjectDeletion(in);      
+}
+
+
+static int yaffs_UnlinkWorker(yaffs_Object *obj)
+{
+
+       
+       if(obj->variantType == YAFFS_OBJECT_TYPE_HARDLINK)
+       {
+               return  yaffs_DeleteHardLink(obj);
+       }
+       else if(!list_empty(&obj->hardLinks))
+       {       
+#if 0
+               // Curve ball: We're unlinking an object that has a hardlink.
+               // Therefore we can't really delete the object.
+               // Instead, we do the following:
+               // - Select a hardlink.
+               // - Re-type a hardlink as the equivalent object and populate the fields, including the
+               //  objectId. Updating the object id is important so that all the hardlinks do not need
+               // to be rewritten.
+               // - Update the equivalet object pointers.
+               // - Delete all object.
+
+               yaffs_Object *hl;
+               struct list_head *i;
+
+
+               yaffs_RemoveObjectFromDirectory(obj);
+
+
+
+               hl =  list_entry(obj->hardLinks.next, yaffs_Object,hardLinks);
+               
+               hl->dirty = 1;
+               hl->st_mode = obj->st_mode;
+               hl->st_uid = obj->st_uid;
+               hl->st_gid = obj->st_gid;
+               hl->st_atime = obj->st_atime;
+               hl->st_mtime = obj->st_mtime;
+               hl->st_ctime = obj->st_ctime;
+               
+               hl->variantType = obj->variantType;
+               
+               switch(hl->variantType)
+               {
+                       case YAFFS_OBJECT_TYPE_FILE:
+                       case YAFFS_OBJECT_TYPE_SYMLINK:
+                               // These types are OK to just copy across.
+                               hl->variant = obj->variant;
+                               break;
+                       case YAFFS_OBJECT_TYPE_DIRECTORY:
+                               // Fix the list up
+                               list_add(&hl->variant.directoryVariant.children,
+                                           &obj->variant.directoryVariant.children);
+                               list_del(&obj->variant.directoryVariant.children);
+                               
+                               // Now change all the directory children to point to the new parent.
+                               list_for_each(i,&hl->variant.directoryVariant.children)
+                               {
+                                       list_entry(i,yaffs_Object,siblings)->parent = hl;
+                               }
+                               break;
+                               
+                       case YAFFS_OBJECT_TYPE_HARDLINK:
+                       case YAFFS_OBJECT_TYPE_UNKNOWN:
+                               // Should not be either of these types.
+               }
+               
+               // Now fix up the hardlink chain
+               list_del(&obj->hardLinks);
+
+               list_for_each(i,&hl->hardLinks)
+               {
+                       list_entry(i,yaffs_Object,hardLinks)->variant.hardLinkVariant.equivalentObject = hl;
+                       list_entry(i,yaffs_Object,hardLinks)->variant.hardLinkVariant.equivalentObjectId = hl->objectId;
+               }
+               
+               // Now fix up the hash links.
+               yaffs_UnhashObject(hl);
+               hl->objectId = obj->objectId;
+               yaffs_HashObject(hl);
+               
+               // Update the hardlink which has become an object
+               yaffs_UpdateObjectHeader(hl,NULL);
+
+               // Finally throw away the deleted object
+               yaffs_DeleteChunk(obj->myDev,obj->chunkId);
+               yaffs_FreeObject(obj);
+               
+               return YAFFS_OK;                
+#else
+               // Curve ball: We're unlinking an object that has a hardlink.
+               //
+               //      This problem arises because we are not strictly following
+               //  The Linux link/inode model.
+               //
+               // We can't really delete the object.
+               // Instead, we do the following:
+               // - Select a hardlink.
+               // - Unhook it from the hard links
+               // - Unhook it from its parent directory (so that the rename can work)
+               // - Rename the object to the hardlink's name.
+               // - Delete the hardlink
+               
+               
+               yaffs_Object *hl;
+               int retVal;
+               char name[YAFFS_MAX_NAME_LENGTH+1];
+               
+               hl = list_entry(obj->hardLinks.next,yaffs_Object,hardLinks);
+               list_del_init(&hl->hardLinks);
+               list_del_init(&hl->siblings);
+               
+               yaffs_GetObjectName(hl,name,YAFFS_MAX_NAME_LENGTH+1);
+               
+               retVal = yaffs_ChangeObjectName(obj, hl->parent, name);
+               if(retVal == YAFFS_OK)
+               {
+                       retVal = yaffs_DoGenericObjectDeletion(hl);
+               }
+               return retVal;
+
+#endif
+
+                               
+       }
+       else
+       {
+               switch(obj->variantType)
+               {
+                       case YAFFS_OBJECT_TYPE_FILE:
+                               return yaffs_DeleteFile(obj);
+                               break;
+                       case YAFFS_OBJECT_TYPE_DIRECTORY:
+                               return yaffs_DeleteDirectory(obj);
+                               break;
+                       case YAFFS_OBJECT_TYPE_SYMLINK:
+                               return yaffs_DeleteSymLink(obj);
+                               break;
+                       case YAFFS_OBJECT_TYPE_HARDLINK:
+                       case YAFFS_OBJECT_TYPE_UNKNOWN:
+                       default:
+                               return YAFFS_FAIL;
+               }
+       }
+}
+
+int yaffs_Unlink(yaffs_Object *dir, const char *name)
+{
+       yaffs_Object *obj;
+       
+        obj = yaffs_FindObjectByName(dir,name);
+        
+        if(obj && obj->unlinkAllowed)
+        {
+               return yaffs_UnlinkWorker(obj);
+        }
+        
+        return YAFFS_FAIL;
+       
+}
+
+//////////////// Initialisation Scanning /////////////////
+
+
+static int yaffs_Scan(yaffs_Device *dev)
+{
+       yaffs_Spare spare;
+       yaffs_Tags tags;
+       int blk;
+       int chunk;
+       int c;
+       int deleted;
+       int inuse;
+       yaffs_BlockState state;
+       yaffs_Object *hardList = NULL;
+       yaffs_Object *hl;
+       
+       __u32 pageBits;
+       
+       yaffs_ObjectHeader *oh;
+       yaffs_Object *in;
+       yaffs_Object *parent;
+       
+       __u8 chunkData[YAFFS_BYTES_PER_CHUNK];
+       
+       for(blk = dev->startBlock; blk <= dev->endBlock; blk++)
+       {
+               deleted = 0;
+               pageBits = 0;
+               inuse = 0;
+               state = YAFFS_BLOCK_STATE_UNKNOWN;
+               
+               for(c = 0; c < YAFFS_CHUNKS_PER_BLOCK && 
+                                  state == YAFFS_BLOCK_STATE_UNKNOWN; c++)
+               {
+                       // Read the spare area and decide what to do
+                       chunk = blk * YAFFS_CHUNKS_PER_BLOCK + c;
+                       yaffs_ReadChunkFromNAND(dev,chunk,NULL,&spare);
+
+                       
+                       // Is this a valid block?
+                       if(yaffs_countBits[spare.blockStatus] >= 7)
+                       {
+                               // This block looks ok, now what's in this chunk?
+                               yaffs_GetTagsFromSpare(&spare,&tags);
+                               
+                               if(tags.objectId == YAFFS_UNUSED_OBJECT_ID)
+                               {
+                                       // An unassigned chunk in the block
+                                       // This means that either the block is empty or 
+                                       // this is the one being allocated from
+                                       
+                                       if(c == 0)
+                                       {
+                                               // the block is unused
+                                               state = YAFFS_BLOCK_STATE_EMPTY;
+                                               dev->nErasedBlocks++;
+                                       }
+                                       else
+                                       {
+                                               // this is the block being allocated from
+                                               T((" allocating %d %d\n",blk,c));
+                                               state = YAFFS_BLOCK_STATE_ALLOCATING;
+                                               dev->allocationBlock = blk;
+                                               dev->allocationPage = c;
+                                       }
+
+                                       dev->nFreeChunks += (YAFFS_CHUNKS_PER_BLOCK - c);
+                               }
+                               else if(tags.objectId == 0)
+                               {
+                                       // A deleted chunk
+                                       deleted++;
+                                       dev->nFreeChunks ++;
+                                       T((" %d %d deleted\n",blk,c));
+                               }
+                               else if(tags.chunkId > 0)
+                               {
+                                       // A data chunk.
+                                       inuse++;
+                                       pageBits |= ( 1 <<c);                           
+                                       in = yaffs_FindOrCreateObjectByNumber(dev,tags.objectId,YAFFS_OBJECT_TYPE_FILE);
+                                       // todo check for a clash (two data chunks with
+                                       // the same chunkId).
+                                       yaffs_PutChunkIntoFile(in,tags.chunkId,chunk);
+                                       T((" %d %d data %d %d\n",blk,c,tags.objectId,tags.chunkId));    
+                               }
+                               else
+                               {
+                                       // chunkId == 0, so it is an ObjectHeader.
+                                       inuse++;                                
+                                       pageBits |= ( 1 <<c);                           
+                                       yaffs_ReadChunkFromNAND(dev,chunk,chunkData,NULL);
+                                       oh = (yaffs_ObjectHeader *)chunkData;
+                                       
+                                       in = yaffs_FindOrCreateObjectByNumber(dev,tags.objectId,oh->type);
+                                       if(in->valid)
+                                       {
+                                               // todo we have already filled this one. We have
+                                               // a duplicate. Need to fix
+                                       }
+                                       
+                                       // we don't have a duplicate...
+                                       
+                                       in->valid = 1;
+                                       in->variantType = oh->type;
+               
+                                       in->st_mode  = oh->st_mode;
+                                       in->st_uid   = oh->st_uid;
+                                       in->st_gid   = oh->st_gid;
+                                       in->st_atime = oh->st_atime;
+                                       in->st_mtime = oh->st_mtime;
+                                       in->st_ctime = oh->st_ctime;
+                                       in->chunkId  = chunk;
+
+                                       in->sum = oh->sum;
+                                       in->dirty = 0;
+                                                               
+                                       // directory stuff...
+                                       // hook up to parent
+               
+                                       parent = yaffs_FindOrCreateObjectByNumber(dev,oh->parentObjectId,YAFFS_OBJECT_TYPE_DIRECTORY);
+                                       if(parent->variantType == YAFFS_OBJECT_TYPE_UNKNOWN)
+                                       {
+                                               // Set up as a directory
+                                               parent->variantType = YAFFS_OBJECT_TYPE_DIRECTORY;
+                                               INIT_LIST_HEAD(&parent->variant.directoryVariant.children);
+                                       }
+                                       else if(parent->variantType != YAFFS_OBJECT_TYPE_DIRECTORY)
+                                       {
+                                               // Hoosterman, another problem....
+                                               // We're trying to use a non-directory as a directory
+                                               // Todo ... handle
+                                       }
+                                       
+                                       yaffs_AddObjectToDirectory(parent,in);  
+                                       
+                                       // Note re hardlinks.
+                                       // Since we might scan a hardlink before its equivalent object is scanned
+                                       // we put them all in a list.
+                                       // After scanning is complete, we should have all the objects, so we run through this
+                                       // list and fix up all the chains.              
+               
+                                       switch(in->variantType)
+                                       {
+                                               case YAFFS_OBJECT_TYPE_UNKNOWN:         // Todo got a problem
+                                                       break;
+                                               case YAFFS_OBJECT_TYPE_FILE:
+                                                       in->variant.fileVariant.fileSize = oh->fileSize;
+                                                       break;
+                                               case YAFFS_OBJECT_TYPE_HARDLINK:
+                                                       in->variant.hardLinkVariant.equivalentObjectId = oh->equivalentObjectId;
+                                                       (yaffs_Object *)(in->hardLinks.next) = hardList;
+                                                       hardList = in;
+                                                       break;
+                                               case YAFFS_OBJECT_TYPE_DIRECTORY:       // Do nothing
+                                                       break;
+                                               case YAFFS_OBJECT_TYPE_SYMLINK:         // Do nothing
+                                                       in->variant.symLinkVariant.alias = yaffs_CloneString(oh->alias);
+                                                       break;
+                                       }
+                                       T((" %d %d header %d \"%s\" type %d\n",blk,c,tags.objectId,oh->name,in->variantType));  
+                               }
+                       }
+                       else
+                       {
+                               // it's a bad block
+                               state = YAFFS_BLOCK_STATE_DEAD;
+                       }                       
+               }
+               
+               if(state == YAFFS_BLOCK_STATE_UNKNOWN)
+               {
+                       // If we got this far, then the block is fully allocated.
+                       // ie. Full or Dirty
+                       state = (inuse) ? YAFFS_BLOCK_STATE_FULL : YAFFS_BLOCK_STATE_DIRTY;
+       
+               }
+               
+               dev->blockInfo[blk].pageBits = pageBits;
+               dev->blockInfo[blk].pagesInUse = inuse;
+               dev->blockInfo[blk].blockState = state;
+               
+       }
+       
+       // Todo fix up the hard link chains
+       while(hardList)
+       {
+               hl = hardList;
+               hardList = (yaffs_Object *)(hardList->hardLinks.next);
+               
+               in = yaffs_FindObjectByNumber(dev,hl->variant.hardLinkVariant.equivalentObjectId);
+               
+               if(in)
+               {
+                       hl->variant.hardLinkVariant.equivalentObject=in;
+                       list_add(&hl->hardLinks,&in->hardLinks);
+               }
+               else
+               {
+                       //Todo Need to report this better.
+                       hl->variant.hardLinkVariant.equivalentObject=NULL;
+                       INIT_LIST_HEAD(&hl->hardLinks);
+                       
+               }
+               
+       }
+       
+       
+       
+       return YAFFS_OK;
+}
+
+
+////////////////////////// Directory Functions /////////////////////////
+
+
+static void yaffs_AddObjectToDirectory(yaffs_Object *directory, yaffs_Object *obj)
+{
+
+       if(obj->siblings.prev == NULL)
+       {
+               // Not initialised
+               INIT_LIST_HEAD(&obj->siblings);
+               
+       }
+       else if(!list_empty(&obj->siblings))
+       {
+               // If it is holed up somewhere else, un hook it
+               list_del_init(&obj->siblings);
+       }
+       // Now add it
+       list_add(&obj->siblings,&directory->variant.directoryVariant.children);
+       obj->parent = directory;
+}
+
+static void yaffs_RemoveObjectFromDirectory(yaffs_Object *obj)
+{
+       list_del_init(&obj->siblings);
+       obj->parent = NULL;
+}
+
+yaffs_Object *yaffs_FindObjectByName(yaffs_Object *directory,const char *name)
+{
+       int sum;
+       
+       struct list_head *i;
+       __u8 buffer[YAFFS_BYTES_PER_CHUNK];
+       yaffs_ObjectHeader *oh = (yaffs_ObjectHeader *)buffer;
+       
+       yaffs_Object *l;
+       
+       sum = yaffs_CalcNameSum(name);
+       
+       list_for_each(i,&directory->variant.directoryVariant.children)
+       {
+               l = list_entry(i, yaffs_Object,siblings);
+               
+               // Special case for lost-n-found
+               if(l->objectId == YAFFS_OBJECTID_LOSTNFOUND)
+               {
+                       if(strcmp(name,YAFFS_LOSTNFOUND_NAME) == 0)
+                       {
+                               return l;
+                       }
+               }
+               else if(l->sum == sum)
+               {
+                       // Do a real check
+                       yaffs_ReadChunkFromNAND(l->myDev,l->chunkId,buffer,NULL);
+                       if(strcmp(name,oh->name) == 0)
+                       {
+                               return l;
+                       }
+                       
+                       
+               }
+       }
+       
+       return NULL;
+}
+
+
+int yaffs_ApplyToDirectoryChildren(yaffs_Object *theDir,int (*fn)(yaffs_Object *))
+{
+       struct list_head *i;    
+       yaffs_Object *l;
+       
+       
+       list_for_each(i,&theDir->variant.directoryVariant.children)
+       {
+               l = list_entry(i, yaffs_Object,siblings);
+               if(!fn(l))
+               {
+                       return YAFFS_FAIL;
+               }
+       }
+       
+       return YAFFS_OK;
+
+}
+
+
+// GetEquivalentObject dereferences any hard links to get to the
+// actual object.
+
+static yaffs_Object *yaffs_GetEquivalentObject(yaffs_Object *obj)
+{
+       if(obj && obj->variantType == YAFFS_OBJECT_TYPE_HARDLINK)
+       {
+               // We want the object id of the equivalent object, not this one
+               obj = obj->variant.hardLinkVariant.equivalentObject;
+       }
+       return obj;
+
+}
+
+int yaffs_GetObjectName(yaffs_Object *obj,char *name,int buffSize)
+{
+       memset(name,0,buffSize);
+       
+       if(obj->objectId == YAFFS_OBJECTID_LOSTNFOUND)
+       {
+               strncpy(name,YAFFS_LOSTNFOUND_NAME,buffSize - 1);
+       }
+       else
+       {
+               __u8 buffer[YAFFS_BYTES_PER_CHUNK];
+               yaffs_ObjectHeader *oh = (yaffs_ObjectHeader *)buffer;
+
+               memset(buffer,0,YAFFS_BYTES_PER_CHUNK);
+       
+               if(obj->chunkId >= 0)
+               {
+                       yaffs_ReadChunkFromNAND(obj->myDev,obj->chunkId,buffer,NULL);
+               }
+               strncpy(name,oh->name,buffSize - 1);
+       }
+       
+       return strlen(name);
+}
+
+int yaffs_GetObjectFileLength(yaffs_Object *obj)
+{
+       
+       // Dereference any hard linking
+       obj = yaffs_GetEquivalentObject(obj);
+       
+       if(obj->variantType == YAFFS_OBJECT_TYPE_FILE)
+       {
+               return obj->variant.fileVariant.fileSize;
+       }
+       if(obj->variantType == YAFFS_OBJECT_TYPE_SYMLINK)
+       {
+               return strlen(obj->variant.symLinkVariant.alias);
+       }
+       else
+       {
+               // Only a directory should drop through to here
+               return YAFFS_BYTES_PER_CHUNK;
+       }       
+}
+
+int yaffs_GetObjectLinkCount(yaffs_Object *obj)
+{
+       int count = 1; // the object itself
+       struct list_head *i;
+       
+       list_for_each(i,&obj->hardLinks)
+       {
+               count++;
+       }
+       return count;
+       
+}
+
+
+int yaffs_GetObjectInode(yaffs_Object *obj)
+{
+       obj = yaffs_GetEquivalentObject(obj);
+       
+       return obj->objectId;
+}
+
+unsigned yaffs_GetObjectType(yaffs_Object *obj)
+{
+       obj = yaffs_GetEquivalentObject(obj);
+       
+       switch(obj->variantType)
+       {
+               case YAFFS_OBJECT_TYPE_FILE:            return DT_REG; break;
+               case YAFFS_OBJECT_TYPE_DIRECTORY:       return DT_DIR; break;
+               case YAFFS_OBJECT_TYPE_SYMLINK:         return DT_LNK; break;
+               case YAFFS_OBJECT_TYPE_HARDLINK:        return DT_REG; break;
+               default: return DT_REG; break;
+       }
+}
+
+char *yaffs_GetSymlinkAlias(yaffs_Object *obj)
+{
+       obj = yaffs_GetEquivalentObject(obj);
+       if(obj->variantType == YAFFS_OBJECT_TYPE_SYMLINK)
+       {
+               return yaffs_CloneString(obj->variant.symLinkVariant.alias);
+       }
+       else
+       {
+               return yaffs_CloneString("");
+       }
+}
+
+
+int yaffs_SetAttributes(yaffs_Object *obj, struct iattr *attr)
+{
+       unsigned int valid = attr->ia_valid;
+       
+       if(valid & ATTR_MODE) obj->st_mode = attr->ia_mode;
+       if(valid & ATTR_UID) obj->st_uid = attr->ia_uid;
+       if(valid & ATTR_GID) obj->st_gid = attr->ia_gid;
+       
+       if(valid & ATTR_ATIME) obj->st_atime = attr->ia_atime;
+       if(valid & ATTR_CTIME) obj->st_ctime = attr->ia_ctime;
+       if(valid & ATTR_MTIME) obj->st_mtime = attr->ia_mtime;
+       
+       if(valid & ATTR_SIZE) yaffs_ResizeFile(obj,attr->ia_size);
+       
+       yaffs_UpdateObjectHeader(obj,NULL);
+       
+       return YAFFS_OK;
+       
+}
+int yaffs_GetAttributes(yaffs_Object *obj, struct iattr *attr)
+{
+       unsigned int valid = 0;
+       
+       attr->ia_mode = obj->st_mode;   valid |= ATTR_MODE;
+       attr->ia_uid = obj->st_uid;             valid |= ATTR_UID;
+       attr->ia_gid = obj->st_gid;             valid |= ATTR_GID;
+       
+       attr->ia_atime = obj->st_atime; valid |= ATTR_ATIME;
+       attr->ia_ctime = obj->st_ctime; valid |= ATTR_CTIME;
+       attr->ia_mtime = obj->st_mtime; valid |= ATTR_MTIME;
+       
+       attr->ia_size = yaffs_GetFileSize(obj); valid |= ATTR_SIZE;
+       
+       attr->ia_valid = valid;
+       
+       return YAFFS_OK;
+       
+}
+
+
+
+int yaffs_DumpObject(yaffs_Object *obj)
+{
+       __u8 buffer[YAFFS_BYTES_PER_CHUNK];
+       char name[256];
+//     yaffs_ObjectHeader *oh = (yaffs_ObjectHeader *)buffer;
+
+       memset(buffer,0,YAFFS_BYTES_PER_CHUNK);
+       
+       if(obj->chunkId >= 0)
+       {
+               yaffs_ReadChunkFromNAND(obj->myDev,obj->chunkId,buffer,NULL);
+       }
+       
+       yaffs_GetObjectName(obj,name,256);
+       
+       YPRINTF(("Object %d \"%s\"\n dirty %d valid %d serial %d sum %d chunk %d type %d size %d\n",
+                       yaffs_GetObjectInode(obj), name, obj->dirty, obj->valid, obj->serial, 
+                       obj->sum, obj->chunkId, yaffs_GetObjectType(obj), yaffs_GetObjectFileLength(obj)));
+
+#if 0
+       YPRINTF(("Object %d \"%s\"\n dirty %d valid %d serial %d sum %d chunk %d\n",
+                       obj->objectId, oh->name, obj->dirty, obj->valid, obj->serial, 
+                       obj->sum, obj->chunkId));
+               switch(obj->variantType)
+       {
+               case YAFFS_OBJECT_TYPE_FILE: 
+                       YPRINTF((" FILE length %d\n",obj->variant.fileVariant.fileSize));
+                       break;
+               case YAFFS_OBJECT_TYPE_DIRECTORY:
+                       YPRINTF((" DIRECTORY\n"));
+                       break;
+               case YAFFS_OBJECT_TYPE_HARDLINK: //todo
+               case YAFFS_OBJECT_TYPE_SYMLINK:
+               case YAFFS_OBJECT_TYPE_UNKNOWN:
+               default:
+       }
+#endif
+       
+       return YAFFS_OK;
+}
+
+
+///////////////////////// Initialisation code ///////////////////////////
+
+
+
+int yaffs_GutsInitialise(yaffs_Device *dev)
+{
+       unsigned  nChunks,x;
+       int bits;
+
+
+       dev = dev;
+       
+       if(!yaffs_CheckStructures())
+       {
+               return YAFFS_FAIL;
+       }
+
+               
+       // OK now calculate a few things for the device
+       // Calculate chunkGroupBits. 
+       // If there are 64k or less chunks then this is 1
+       // Else it is log2(nChunks) - 16
+       //
+       x = nChunks = YAFFS_CHUNKS_PER_BLOCK * dev->nBlocks;
+       
+       for(bits = 0, x = nChunks; (x & 1) == 0; bits++)
+       {
+               x >>= 1;
+       }
+       
+       if( x != 1)
+       {
+               // Not a power of 2
+               YPRINTF(("nBlocks should be a power of 2 but is %u\n",
+                       dev->nBlocks));
+               return YAFFS_FAIL;
+       }
+       
+       if(bits <= 16) 
+       {
+               dev->chunkGroupBits = 0;
+               dev->chunkGroupSize = 1;
+       }
+       else
+       {
+               dev->chunkGroupBits = bits - 16;
+               dev->chunkGroupSize = nChunks/0x10000;
+       }
+       
+       // More device initialisation
+       dev->garbageCollectionRequired  = 0;
+       dev->currentDirtyChecker = 0;
+       
+       yaffs_InitialiseBlocks(dev);
+       
+       yaffs_InitialiseTnodes(dev);
+
+       yaffs_InitialiseObjects(dev);
+       
+       
+       // Initialise the root and lost and found directories
+       dev->lostNFoundDir = dev->rootDir = NULL;
+       dev->rootDir = yaffs_CreateFakeDirectory(dev,YAFFS_OBJECTID_ROOT,YAFFS_ROOT_MODE | S_IFDIR);
+       dev->lostNFoundDir = yaffs_CreateFakeDirectory(dev,YAFFS_OBJECTID_LOSTNFOUND,YAFFS_ROOT_MODE | S_IFDIR);
+       yaffs_AddObjectToDirectory(dev->rootDir,dev->lostNFoundDir);
+               
+       // Now scan the flash.  
+       yaffs_Scan(dev);
+
+       
+       return YAFFS_OK;
+               
+}
+
+void yaffs_Deinitialise(yaffs_Device *dev)
+{
+       yaffs_DeinitialiseBlocks(dev);
+       yaffs_DeinitialiseTnodes(dev);
+       yaffs_DeinitialiseObjects(dev);
+       
+}
+
+int  yaffs_GetNumberOfFreeChunks(yaffs_Device *dev)
+{
+       int nFree = dev->nFreeChunks - (YAFFS_CHUNKS_PER_BLOCK * YAFFS_RESERVED_BLOCKS);
+
+       return (nFree < 0) ? 0 : nFree; 
+       
+}
+
+
+/////////////////// YAFFS test code //////////////////////////////////
+
+#define yaffs_CheckStruct(structure,syze, name) \
+           if(sizeof(structure) != syze) \
+              { YPRINTF(("%s should be %d but is %d\n",name,syze,sizeof(structure))); \
+                return YAFFS_FAIL; \
+                  }
+                
+                
+static int yaffs_CheckStructures(void)
+{
+       yaffs_CheckStruct(yaffs_Tags,8,"yaffs_Tags")
+       yaffs_CheckStruct(yaffs_TagsUnion,8,"yaffs_TagsUnion")
+       yaffs_CheckStruct(yaffs_Spare,16,"yaffs_Spare")
+       yaffs_CheckStruct(yaffs_Tnode,2* YAFFS_NTNODES_LEVEL0,"yaffs_Tnode")
+       yaffs_CheckStruct(yaffs_ObjectHeader,512,"yaffs_ObjectHeader")
+       
+       
+       return YAFFS_OK;
+}
+
+void yaffs_GutsTest(yaffs_Device *dev)
+{
+       
+       if(yaffs_CheckStructures() != YAFFS_OK)
+       {
+               YPRINTF(("One or more structures malformed-- aborting\n"));
+       }
+       else
+       {
+               YPRINTF(("Structures OK\n"));
+       }
+       
+       yaffs_TnodeTest(dev);
+       yaffs_ObjectTest(dev);  
+}
+
+
diff --git a/yaffs_guts.h b/yaffs_guts.h
new file mode 100644 (file)
index 0000000..d1e2973
--- /dev/null
@@ -0,0 +1,431 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * yaffs_guts.h: Configuration etc for yaffs_guts
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#ifndef __YAFFS_GUTS_H__
+#define __YAFFS_GUTS_H__
+
+#include "devextras.h"
+
+
+#define YAFFS_OK       1
+#define YAFFS_FAIL  0
+
+// Y=0x59, A=0x41, S=0x53
+#define YAFFS_MAGIC                                    0x5941FF53
+
+#define YAFFS_NTNODES_LEVEL0           16
+#define YAFFS_TNODES_LEVEL0_BITS       4
+#define YAFFS_TNODES_LEVEL0_MASK       0xf
+
+#define YAFFS_NTNODES_INTERNAL                 (YAFFS_NTNODES_LEVEL0 / 2)
+#define YAFFS_TNODES_INTERNAL_BITS     (YAFFS_TNODES_LEVEL0_BITS - 1)
+#define YAFFS_TNODES_INTERNAL_MASK     0x7
+#define YAFFS_TNODES_MAX_LEVEL         6
+               
+#define YAFFS_BYTES_PER_CHUNK          512
+#define YAFFS_CHUNK_SIZE_SHIFT         9
+
+#define YAFFS_BYTES_PER_SPARE          16
+
+#define YAFFS_CHUNKS_PER_BLOCK         32
+#define YAFFS_BYTES_PER_BLOCK          (YAFFS_CHUNKS_PER_BLOCK*YAFFS_BYTES_PER_CHUNK)
+
+#define YAFFS_MAX_CHUNK_ID                     0x000FFFFF
+
+#define YAFFS_UNUSED_OBJECT_ID         0x0003FFFF
+
+#define YAFFS_ALLOCATION_NOBJECTS      100
+#define YAFFS_ALLOCATION_NTNODES       100
+#define YAFFS_ALLOCATION_NLINKS                100
+
+#define YAFFS_NOBJECT_BUCKETS          256
+
+
+#define YAFFS_RESERVED_BLOCKS          5
+
+#define YAFFS_OBJECT_SPACE                     0x40000
+#define YAFFS_MAX_NAME_LENGTH          255
+
+#define YAFFS_MAX_ALIAS_LENGTH         211
+
+#define YAFFS_OBJECTID_ROOT                    1
+#define YAFFS_ROOT_MODE                                0666
+#define YAFFS_OBJECTID_LOSTNFOUND      2
+#define YAFFS_LOSTNFOUND_NAME          "lost+found"
+
+// Tags structures in RAM
+// NB This uses bitfield. Bitfields should not stradle a u32 boundary otherwise
+// the structure size will get blown out.
+
+typedef struct
+{
+    unsigned chunkId:20;
+    unsigned serialNumber:2;
+    unsigned byteCount:10;
+    unsigned objectId:18;
+    unsigned ecc:12;
+    unsigned unusedStuff:2;
+} yaffs_Tags;
+
+typedef union
+{
+    yaffs_Tags asTags;
+    __u8       asBytes[8];
+} yaffs_TagsUnion;
+
+
+// Spare structure
+typedef struct
+{
+    __u8  tagByte0;
+    __u8  tagByte1;
+    __u8  tagByte2;
+    __u8  tagByte3;
+    __u8  pageStatus;
+    __u8  blockStatus;
+    __u8  tagByte4;
+    __u8  tagByte5;
+    __u8  ecc1[3];
+    __u8  tagByte6;
+    __u8  tagByte7;
+    __u8  ecc2[3];
+} yaffs_Spare;
+
+// Block data in RAM
+
+typedef enum {
+       YAFFS_BLOCK_STATE_UNKNOWN       = 0,
+       
+       YAFFS_BLOCK_STATE_EMPTY,                // This block is empty
+       
+       YAFFS_BLOCK_STATE_ALLOCATING,   // This block is partially allocated. 
+                                                                       // This is the one currently being used for page
+                                                                       // allocation. Should never be more than one of these
+                                                       
+
+       YAFFS_BLOCK_STATE_FULL,                 // All the pages in this block have been allocated.
+                                                                       // At least one page holds valid data.
+                                                        
+       YAFFS_BLOCK_STATE_DIRTY,                // All pages have been allocated and deleted. 
+                                                                       // Erase me, reuse me.
+                                                       
+       YAFFS_BLOCK_STATE_DEAD = 0x99   // This block has failed and is not in use
+
+} yaffs_BlockState;
+
+
+
+
+typedef struct
+{
+       __u32 pageBits;   // bitmap of pages in use
+    __u8  blockState; // One of the above block states
+    __u8  pagesInUse; // number of pages in use
+} yaffs_BlockInfo;
+
+
+//////////////////// Object structure ///////////////////////////
+// This is the object structure as stored on NAND
+
+typedef enum
+{
+       YAFFS_OBJECT_TYPE_UNKNOWN,
+       YAFFS_OBJECT_TYPE_FILE,
+       YAFFS_OBJECT_TYPE_SYMLINK,
+       YAFFS_OBJECT_TYPE_DIRECTORY,
+       YAFFS_OBJECT_TYPE_HARDLINK
+} yaffs_ObjectType;
+
+typedef struct
+{
+       yaffs_ObjectType type;
+
+       // Apply to everything  
+       int   parentObjectId;
+       __u16 sum;      // checksum of name
+       char  name[YAFFS_MAX_NAME_LENGTH + 1];
+
+       // Thes following apply to directories, files, symlinks - not hard links
+       __u32 st_mode;  // protection
+       __u32 st_uid;   // user ID of owner
+       __u32 st_gid;    // group ID of owner 
+       __u32 st_atime; // time of last access
+       __u32 st_mtime; // time of last modification
+       __u32 st_ctime; // time of last change
+       
+       // File size  applies to files only
+       int fileSize; 
+               
+       // Equivalent object id applies to hard links only.
+       int  equivalentObjectId;
+       char alias[YAFFS_MAX_ALIAS_LENGTH + 1];
+       
+       
+} yaffs_ObjectHeader;
+
+
+
+////////////////////  Tnode ///////////////////////////
+
+union yaffs_Tnode_union
+{
+       union yaffs_Tnode_union *internal[YAFFS_NTNODES_INTERNAL];
+       __u16 level0[YAFFS_NTNODES_LEVEL0];
+       
+};
+
+typedef union yaffs_Tnode_union yaffs_Tnode;
+
+struct yaffs_TnodeList_struct
+{
+       struct yaffs_TnodeList_struct *next;
+       yaffs_Tnode *tnodes;
+};
+
+typedef struct yaffs_TnodeList_struct yaffs_TnodeList;
+
+
+
+///////////////////  Object ////////////////////////////////
+// An object can be one of:
+// - a directory (no data, has children links
+// - a regular file (data.... not prunes :->).
+// - a symlink [symbolic link] (the alias).
+// - a hard link
+
+
+typedef struct 
+{
+       __u32 fileSize;
+       __u32 topLevel;
+       yaffs_Tnode *top;
+} yaffs_FileStructure;
+
+typedef struct
+{
+       struct list_head children; // list of child links
+} yaffs_DirectoryStructure;
+
+typedef struct
+{
+       char *alias;
+} yaffs_SymLinkStructure;
+
+typedef struct
+{
+       struct yaffs_ObjectStruct *equivalentObject;
+       __u32   equivalentObjectId;
+} yaffs_HardLinkStructure;
+
+typedef union
+{
+       yaffs_FileStructure fileVariant;
+       yaffs_DirectoryStructure directoryVariant;
+       yaffs_SymLinkStructure symLinkVariant;
+       yaffs_HardLinkStructure hardLinkVariant;
+} yaffs_ObjectVariant;
+
+
+struct  yaffs_ObjectStruct
+{
+       __u8 fake:1;                    // A fake object has no presence on NAND.
+       __u8 renameAllowed:1;
+       __u8 unlinkAllowed:1;
+       __u8 dirty:1;                   // the object needs to be written to flash
+       __u8 valid:1;                   // When the file system is being loaded up, this 
+                                                       // object might be created before the data
+                                                       // is available (ie. file data records appear before the header).
+       __u8 serial;                    // serial number of chunk in NAND. Store here so we don't have to
+                                                       // read back the old one to update.
+       __u16 sum;                              // sum of the name to speed searching
+       
+       struct yaffs_DeviceStruct *myDev; // The device I'm on
+       
+                                                               
+       struct list_head hashLink;      // list of objects in this hash bucket
+                                                       
+
+       struct list_head hardLinks; // all the equivalent hard linked objects
+                                                               // live on this list
+       // directory structure stuff
+       struct yaffs_ObjectStruct  *parent;     //my parent directory
+       struct list_head siblings;      // siblings in a directory
+                                                               // also used for linking up the free list
+               
+       // Where's my data in NAND?
+       int chunkId;            // where it lives
+       
+       __u32 objectId;         // the object id value
+       
+       
+       __u32 st_mode;          // protection
+       __u32 st_uid;           // user ID of owner
+       __u32 st_gid;           // group ID of owner 
+       __u32 st_atime;         // time of last access
+       __u32 st_mtime;         // time of last modification
+       __u32 st_ctime;         // time of last change
+
+       
+       yaffs_ObjectType variantType;
+       
+       yaffs_ObjectVariant variant;
+       
+};
+
+
+
+typedef struct yaffs_ObjectStruct yaffs_Object;
+
+
+struct yaffs_ObjectList_struct
+{
+       yaffs_Object *objects;
+       struct yaffs_ObjectList_struct *next;
+};
+
+typedef struct yaffs_ObjectList_struct yaffs_ObjectList;
+
+typedef struct
+{
+       struct list_head list;
+       __u32 count;
+} yaffs_ObjectBucket;
+
+
+//////////////////// Device ////////////////////////////////
+
+struct yaffs_DeviceStruct
+{
+       // Entry parameters set up way early. Yaffs sets up the rest.
+       __u32 nBlocks;          // Size of whole device in blocks
+       __u32 startBlock;       // Start block we're allowed to use
+       __u32 endBlock;         // End block we're allowed to use
+       __u16 chunkGroupBits; // 0 for devices <= 32MB. else log2(nchunks) - 16
+       __u16 chunkGroupSize; // == 2^^chunkGroupBits
+       
+       
+       void *genericDevice; // Pointer to device context
+                                                // On an mtd this holds the mtd pointer.
+       struct semaphore sem;// Semaphore for waiting on erasure.
+       
+       
+       // NAND access functions (Must be set before calling YAFFS)
+       
+       int (*writeChunkToNAND)(struct yaffs_DeviceStruct *dev,int chunkInNAND, const __u8 *data, yaffs_Spare *spare);
+       int (*readChunkFromNAND)(struct yaffs_DeviceStruct *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare);
+       int (*eraseBlockInNAND)(struct yaffs_DeviceStruct *dev,int blockInNAND);        
+       int (*initialiseNAND)(struct yaffs_DeviceStruct *dev);
+       
+
+       
+       // Runtime parameters.
+       yaffs_BlockInfo *blockInfo;
+       int   nErasedBlocks;
+       int   allocationBlock;
+       __u32 allocationPage;
+       
+       // Runtime state
+       int   nTnodesCreated;   
+       yaffs_Tnode *freeTnodes;
+       int  nFreeTnodes;
+       yaffs_TnodeList *allocatedTnodeList;
+
+
+       int   nObjectsCreated;
+       yaffs_Object *freeObjects;
+       int   nFreeObjects;
+
+       yaffs_ObjectList *allocatedObjectList;
+
+       yaffs_ObjectBucket objectBucket[YAFFS_NOBJECT_BUCKETS];
+
+       int       nFreeChunks;
+               
+       int   currentDirtyChecker;      // Used to find current dirtiest block
+       
+       int   garbageCollectionRequired;
+       
+       yaffs_Object *rootDir;
+       yaffs_Object *lostNFoundDir;
+       
+       
+};
+
+ typedef struct yaffs_DeviceStruct yaffs_Device;
+
+
+
+//////////// YAFFS Functions //////////////////
+
+int yaffs_GutsInitialise(yaffs_Device *dev);
+void yaffs_Deinitialise(yaffs_Device *dev);
+
+int yaffs_GetNumberOfFreeChunks(yaffs_Device *dev);
+
+
+// Rename
+int yaffs_RenameObject(yaffs_Object *oldDir, const char *oldName, yaffs_Object *newDir, const char *newName);
+
+// generic Object functions
+int yaffs_Unlink(yaffs_Object *dir, const char *name);
+
+// Object access functions.
+int yaffs_GetObjectName(yaffs_Object *obj,char *name,int buffSize);
+int yaffs_GetObjectFileLength(yaffs_Object *obj);
+int yaffs_GetObjectInode(yaffs_Object *obj);
+unsigned yaffs_GetObjectType(yaffs_Object *obj);
+int yaffs_GetObjectLinkCount(yaffs_Object *obj);
+
+// Change inode attributes
+int yaffs_SetAttributes(yaffs_Object *obj, struct iattr *attr);
+int yaffs_GetAttributes(yaffs_Object *obj, struct iattr *attr);
+
+// File operations
+int yaffs_ReadDataFromFile(yaffs_Object *obj, __u8 *buffer, __u32 offset, int nBytes);
+int yaffs_WriteDataToFile(yaffs_Object *obj, const __u8 *buffer, __u32 offset, int nBytes);
+int yaffs_ResizeFile(yaffs_Object *obj, int newSize);
+
+yaffs_Object *yaffs_MknodFile(yaffs_Object *parent,const char *name, __u32 mode, __u32 uid, __u32 gid);
+int yaffs_FlushFile(yaffs_Object *obj);
+
+
+// Directory operations
+yaffs_Object *yaffs_MknodDirectory(yaffs_Object *parent,const char *name, __u32 mode, __u32 uid, __u32 gid);
+yaffs_Object *yaffs_FindObjectByName(yaffs_Object *theDir,const char *name);
+int yaffs_ApplyToDirectoryChildren(yaffs_Object *theDir,int (*fn)(yaffs_Object *));
+
+yaffs_Object *yaffs_FindObjectByNumber(yaffs_Device *dev,int number);
+
+// Link operations
+yaffs_Object *yaffs_Link(yaffs_Object *parent, const char *name, yaffs_Object *equivalentObject);
+
+// Symlink operations
+yaffs_Object *yaffs_MknodSymLink(yaffs_Object *parent, const char *name, __u32 mode,  __u32 uid, __u32 gid, const char *alias);
+char *yaffs_GetSymlinkAlias(yaffs_Object *obj);
+
+
+// Special directories
+yaffs_Object *yaffs_Root(yaffs_Device *dev);
+yaffs_Object *yaffs_LostNFound(yaffs_Device *dev);
+
+
+// Debug dump 
+int yaffs_DumpObject(yaffs_Object *obj);
+
+
+void yaffs_GutsTest(yaffs_Device *dev);
+
+
+#endif
diff --git a/yaffs_mtdif.c b/yaffs_mtdif.c
new file mode 100644 (file)
index 0000000..3f1e924
--- /dev/null
@@ -0,0 +1,104 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * yaffs_mtdif.c  NAND mtd wrapper functions.
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+ #ifdef YAFFS_MTD_ENABLED
+#include "yportenv.h"
+
+#include "yaffs_mtdif.h"
+
+#include "linux/mtd/mtd.h"
+#include "linux/types.h"
+
+
+int nandmtd_WriteChunkToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_Spare *spare)
+{
+       struct mtd_info *mtd = (struct mtd_info *)(dev->genericDevice);
+       size_t dummy;
+       
+       loff_t addr = ((loff_t)chunkInNAND) * YAFFS_BYTES_PER_CHUNK;
+       
+       
+       __u8 *spareAsBytes = (__u8 *)spare;
+       
+       if(data)
+               mtd->write(mtd,addr,YAFFS_BYTES_PER_CHUNK,&dummy,data);
+       if(spare)
+               mtd->write_oob(mtd,addr,YAFFS_BYTES_PER_SPARE,&dummy,spareAsBytes);
+
+       return YAFFS_OK;
+}
+
+
+int nandmtd_ReadChunkFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare)
+{
+       struct mtd_info *mtd = (struct mtd_info *)(dev->genericDevice);
+       size_t dummy;
+       
+       loff_t addr = ((loff_t)chunkInNAND) * YAFFS_BYTES_PER_CHUNK;
+       
+       __u8 *spareAsBytes = (__u8 *)spare;
+       
+       if(data)
+               mtd->read(mtd,addr,YAFFS_BYTES_PER_CHUNK,&dummy,data);
+       if(spare)
+               mtd->read_oob(mtd,addr,YAFFS_BYTES_PER_SPARE,&dummy,spareAsBytes);
+
+       return YAFFS_OK;
+}
+
+
+static void nandmtd_EraseCallback(struct erase_info *ei)
+{
+       yaffs_Device *dev = (yaffs_Device *)ei->priv;   
+       up(&dev->sem);
+}
+
+
+int nandmtd_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
+{
+       
+       struct mtd_info *mtd = (struct mtd_info *)(dev->genericDevice);
+       __u32 addr = ((loff_t) blockNumber) * YAFFS_BYTES_PER_BLOCK;
+       struct erase_info ei;
+       
+       ei.mtd = mtd;
+       ei.addr = addr;
+       ei.len = YAFFS_BYTES_PER_BLOCK;
+       ei.time = 1000;
+       ei.retries = 2;
+       ei.callback = nandmtd_EraseCallback;
+       ei.priv = (u_long)dev;
+       
+       // Todo finish off the ei if required
+       
+       sema_init(&dev->sem,0);
+
+       mtd->erase(mtd,&ei);
+       
+       
+       down(&dev->sem); // Wait for the erasure to complete
+                       
+       //Todo, check result of erasure
+       
+       return YAFFS_OK;
+}
+
+int nandmtd_InitialiseNAND(yaffs_Device *dev)
+{
+       return YAFFS_OK;
+}
+
+#endif // YAFFS_MTD_ENABLED
+
diff --git a/yaffs_mtdif.h b/yaffs_mtdif.h
new file mode 100644 (file)
index 0000000..6dc2e1b
--- /dev/null
@@ -0,0 +1,29 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * yaffs_mtdif.h  NAND mtd interface wrappers
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#ifndef __YAFFS_MTDIF_H__
+#define __YAFFS_MTDIF_H__
+
+#include "yaffs_guts.h"
+
+int nandmtd_WriteChunkToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_Spare *spare);
+int nandmtd_ReadChunkFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare);
+int nandmtd_EraseBlockInNAND(yaffs_Device *dev, int blockNumber);
+int nandmtd_InitialiseNAND(yaffs_Device *dev);
+#endif
+
+
+
+
diff --git a/yaffs_nandemul.h b/yaffs_nandemul.h
new file mode 100644 (file)
index 0000000..f233408
--- /dev/null
@@ -0,0 +1,34 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * yaffs_nandemul.h: Interface to emulated NAND functions
+ *
+ */
+#ifndef __YAFFS_NANDEMUL_H__
+#define __YAFFS_NANDEMUL_H__
+
+#include "yaffs_guts.h" 
+/* WriteChunkToNAND and ReadChunkFromNAND are used with two pointers. 
+ * If either of these pointers are null, then that field will not be 
+ * transferred.
+ */
+int nandemul_WriteChunkToNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND, const __u8 *data, yaffs_Spare *spare);
+int nandemul_ReadChunkFromNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare);
+int nandemul_EraseBlockInNAND(struct yaffs_DeviceStruct *dev,int blockInNAND);
+int nandemul_InitialiseNAND(struct yaffs_DeviceStruct *dev);
+
+#endif
+
diff --git a/yaffs_ramem.c b/yaffs_ramem.c
new file mode 100644 (file)
index 0000000..7143dff
--- /dev/null
@@ -0,0 +1,291 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * yaffs_ramem.c  NAND emulation on top of a chunk of RAM
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+ //yaffs_ramem.c
+ // Since this creates the RAM block at start up it is pretty useless for testing the scanner.
+
+#ifdef YAFFS_RAM_ENABLED
+
+#include "yportenv.h"
+
+#include "yaffs_nandemul.h"
+#include "yaffs_guts.h"
+#include "yaffsinterface.h"
+#include "devextras.h"
+
+
+#define EM_SIZE_IN_MEG 2
+
+#define BLOCK_SIZE (32 * 528)
+#define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
+#define FILE_SIZE_IN_BLOCKS (FILE_SIZE_IN_MEG * BLOCKS_PER_MEG)
+#define FILE_SIZE_IN_BYTES (FILE_SIZE_IN_BLOCKS * BLOCK_SIZE)
+
+#define T(x) YPRINTF(x)
+
+#define DEFAULT_SIZE_IN_MB 2
+
+typedef struct 
+{
+       __u8 data[528]; // Data + spare
+       int count[3];   // The programming count for each area of
+                       // the page (0..255,256..511,512..527
+       int empty;      // is this empty?
+} nandemul_Page;
+
+typedef struct
+{
+       nandemul_Page page[32]; // The pages in the block
+       __u8 damaged;           // Is the block damaged?
+       
+} nandemul_Block;
+
+
+
+typedef struct
+{
+       nandemul_Block **block;
+       int nBlocks;
+} nandemul_Device;
+
+static nandemul_Device ned;
+
+int sizeInMB = DEFAULT_SIZE_IN_MB;
+
+
+static void nandemul_ReallyEraseBlock(int blockNumber)
+{
+       int i;
+       
+       nandemul_Block *theBlock = ned.block[blockNumber];
+       
+       for(i = 0; i < 32; i++)
+       {
+               memset(theBlock->page[i].data,0xff,528);
+               theBlock->page[i].count[0] = 0;
+               theBlock->page[i].count[1] = 0;
+               theBlock->page[i].count[2] = 0;
+               theBlock->page[i].empty = 1;
+       }
+
+}
+
+
+int nandemul_CalcNBlocks(void)
+{
+        switch(sizeInMB)
+        {
+               case 8:
+               case 16:
+               case 32:
+               case 64:
+               case 128:
+               case 256:
+               case 512:
+                       break;
+               default:
+                       sizeInMB = DEFAULT_SIZE_IN_MB;
+        }
+       return sizeInMB * 64;
+}
+
+
+
+static int  CheckInit(void)
+{
+       static int initialised = 0;
+       
+       int i;
+       int fail = 0;
+       int nBlocks; 
+       int nAllocated = 0;
+       
+       if(initialised) 
+       {
+               return YAFFS_OK;
+       }
+       
+       
+       nBlocks = nandemul_CalcNBlocks();
+       
+       ned.block = YMALLOC(sizeof(nandemul_Block *) * nBlocks);
+       
+       if(!ned.block) return 0;
+       
+       for(i=0; i <nBlocks; i++)
+       {
+               ned.block[i] = NULL;
+       }
+       
+       for(i=0; i <nBlocks && !fail; i++)
+       {
+               if((ned.block[i] = YMALLOC(sizeof(nandemul_Block))) == 0)
+               {
+                       fail = 1;
+               }
+               else
+               {
+                       nandemul_ReallyEraseBlock(i);
+                       ned.block[i]->damaged = 0;
+                       nAllocated++;
+               }
+       }
+       
+       if(fail)
+       {
+               for(i = 0; i < nAllocated; i++)
+               {
+                       YFREE(ned.block[i]);
+               }
+               YFREE(ned.block);
+               
+               T(("Allocation failed, could only allocate %dMB of %dMB requested.\n",
+                  nAllocated/64,sizeInMB));
+               return 0;
+       }
+       
+       ned.nBlocks = nBlocks;
+       
+       initialised = 1;
+       
+       return 1;
+}
+
+int nandemul_WriteChunkToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_Spare *spare)
+{
+       int blk;
+       int pg;
+       int i;
+       
+       __u8 *x;
+       
+       __u8 *spareAsBytes = (__u8 *)spare;
+
+       
+       CheckInit();
+       
+       blk = chunkInNAND/32;
+       pg = chunkInNAND%32;
+       
+       
+       if(data)
+       {
+               x = ned.block[blk]->page[pg].data;
+               
+               for(i = 0; i < 512; i++)
+               {
+                       x[i] &=data[i];
+               }
+               
+               ned.block[blk]->page[pg].count[0]++;
+               ned.block[blk]->page[pg].count[1]++;
+               ned.block[blk]->page[pg].empty = 0;
+       }
+       
+       
+       if(spare)
+       {
+               x = &ned.block[blk]->page[pg].data[512];
+                       
+               for(i = 0; i < 16; i++)
+               {
+                       x[i] &=spareAsBytes[i];
+               }
+               ned.block[blk]->page[pg].count[2]++;
+       }
+
+       return YAFFS_OK;
+}
+
+
+int nandemul_ReadChunkFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare)
+{
+       int blk;
+       int pg;
+
+       
+       CheckInit();
+       
+       blk = chunkInNAND/32;
+       pg = chunkInNAND%32;
+       
+       
+       if(data)
+       {
+               memcpy(data,ned.block[blk]->page[pg].data,512);
+       }
+       
+       
+       if(spare)
+       {
+               memcpy(spare,&ned.block[blk]->page[pg].data[512],16);
+       }
+
+       return YAFFS_OK;
+}
+
+
+int nandemul_CheckChunkErased(yaffs_Device *dev,int chunkInNAND)
+{
+       int blk;
+       int pg;
+       int i;
+
+       
+       CheckInit();
+       
+       blk = chunkInNAND/32;
+       pg = chunkInNAND%32;
+       
+       
+       for(i = 0; i < 528; i++)
+       {
+               if(ned.block[blk]->page[pg].data[i] != 0xFF)
+               {
+                       return YAFFS_FAIL;
+               }
+       }
+
+       return YAFFS_OK;
+
+}
+
+int nandemul_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
+{
+       
+       CheckInit();
+       
+       if(blockNumber < 0 || blockNumber >= ned.nBlocks)
+       {
+               T(("Attempt to erase non-existant block %d\n",blockNumber));
+       }
+       else if(ned.block[blockNumber]->damaged)
+       {
+               T(("Attempt to erase damaged block %d\n",blockNumber));
+       }
+       else
+       {
+               nandemul_ReallyEraseBlock(blockNumber);
+       }
+       
+       return YAFFS_OK;
+}
+
+int nandemul_InitialiseNAND(yaffs_Device *dev)
+{
+       return YAFFS_OK;
+}
+
+#endif //YAFFS_RAM_ENABLED
+
diff --git a/yaffs_super.c b/yaffs_super.c
new file mode 100644 (file)
index 0000000..04dc17e
--- /dev/null
@@ -0,0 +1,401 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2001 Red Hat, Inc.
+ *
+ * Created by David Woodhouse <dwmw2@cambridge.redhat.com>
+ *
+ * The original JFFS, from which the design for JFFS2 was derived,
+ * was designed and implemented by Axis Communications AB.
+ *
+ * The contents of this file are subject to the Red Hat eCos Public
+ * License Version 1.1 (the "Licence"); you may not use this file
+ * except in compliance with the Licence.  You may obtain a copy of
+ * the Licence at http://www.redhat.com/
+ *
+ * Software distributed under the Licence is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing rights and
+ * limitations under the Licence.
+ *
+ * The Original Code is JFFS2 - Journalling Flash File System, version 2
+ *
+ * Alternatively, the contents of this file may be used under the
+ * terms of the GNU General Public License version 2 (the "GPL"), in
+ * which case the provisions of the GPL are applicable instead of the
+ * above.  If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the RHEPL, indicate your decision by
+ * deleting the provisions above and replace them with the notice and
+ * other provisions required by the GPL.  If you do not delete the
+ * provisions above, a recipient may use your version of this file
+ * under either the RHEPL or the GPL.
+ *
+ * $Id: yaffs_super.c,v 1.1 2002-05-20 17:42:08 aleph1 Exp $
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/jffs2.h>
+#include <linux/pagemap.h>
+#include <linux/mtd/mtd.h>
+#include <linux/interrupt.h>
+#include "nodelist.h"
+
+#ifndef MTD_BLOCK_MAJOR
+#define MTD_BLOCK_MAJOR 31
+#endif
+
+extern void jffs2_read_inode (struct inode *);
+void jffs2_put_super (struct super_block *);
+void jffs2_write_super (struct super_block *);
+static int jffs2_statfs (struct super_block *, struct statfs *);
+int jffs2_remount_fs (struct super_block *, int *, char *);
+extern void jffs2_clear_inode (struct inode *);
+
+static struct super_operations jffs2_super_operations =
+{
+       read_inode:     jffs2_read_inode,
+//     delete_inode:   jffs2_delete_inode,
+       put_super:      jffs2_put_super,
+       write_super:    jffs2_write_super,
+       statfs:         jffs2_statfs,
+       remount_fs:     jffs2_remount_fs,
+       clear_inode:    jffs2_clear_inode
+};
+
+static int jffs2_statfs(struct super_block *sb, struct statfs *buf)
+{
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
+       unsigned long avail;
+
+       buf->f_type = JFFS2_SUPER_MAGIC;
+       buf->f_bsize = 1 << PAGE_SHIFT;
+       buf->f_blocks = c->flash_size >> PAGE_SHIFT;
+       buf->f_files = 0;
+       buf->f_ffree = 0;
+       buf->f_namelen = JFFS2_MAX_NAME_LEN;
+
+       spin_lock_bh(&c->erase_completion_lock);
+
+       avail = c->dirty_size + c->free_size;
+       if (avail > c->sector_size * JFFS2_RESERVED_BLOCKS_WRITE)
+               avail -= c->sector_size * JFFS2_RESERVED_BLOCKS_WRITE;
+       else
+               avail = 0;
+
+       buf->f_bavail = buf->f_bfree = avail >> PAGE_SHIFT;
+
+#if CONFIG_JFFS2_FS_DEBUG > 0
+       printk(KERN_DEBUG "STATFS:\n");
+       printk(KERN_DEBUG "flash_size: %08x\n", c->flash_size);
+       printk(KERN_DEBUG "used_size: %08x\n", c->used_size);
+       printk(KERN_DEBUG "dirty_size: %08x\n", c->dirty_size);
+       printk(KERN_DEBUG "free_size: %08x\n", c->free_size);
+       printk(KERN_DEBUG "erasing_size: %08x\n", c->erasing_size);
+       printk(KERN_DEBUG "bad_size: %08x\n", c->bad_size);
+       printk(KERN_DEBUG "sector_size: %08x\n", c->sector_size);
+
+       if (c->nextblock) {
+               printk(KERN_DEBUG "nextblock: 0x%08x\n", c->nextblock->offset);
+       } else {
+               printk(KERN_DEBUG "nextblock: NULL\n");
+       }
+       if (c->gcblock) {
+               printk(KERN_DEBUG "gcblock: 0x%08x\n", c->gcblock->offset);
+       } else {
+               printk(KERN_DEBUG "gcblock: NULL\n");
+       }
+       if (list_empty(&c->clean_list)) {
+               printk(KERN_DEBUG "clean_list: empty\n");
+       } else {
+               struct list_head *this;
+
+               list_for_each(this, &c->clean_list) {
+                       struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+                       printk(KERN_DEBUG "clean_list: %08x\n", jeb->offset);
+               }
+       }
+       if (list_empty(&c->dirty_list)) {
+               printk(KERN_DEBUG "dirty_list: empty\n");
+       } else {
+               struct list_head *this;
+
+               list_for_each(this, &c->dirty_list) {
+                       struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+                       printk(KERN_DEBUG "dirty_list: %08x\n", jeb->offset);
+               }
+       }
+       if (list_empty(&c->erasing_list)) {
+               printk(KERN_DEBUG "erasing_list: empty\n");
+       } else {
+               struct list_head *this;
+
+               list_for_each(this, &c->erasing_list) {
+                       struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+                       printk(KERN_DEBUG "erasing_list: %08x\n", jeb->offset);
+               }
+       }
+       if (list_empty(&c->erase_pending_list)) {
+               printk(KERN_DEBUG "erase_pending_list: empty\n");
+       } else {
+               struct list_head *this;
+
+               list_for_each(this, &c->erase_pending_list) {
+                       struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+                       printk(KERN_DEBUG "erase_pending_list: %08x\n", jeb->offset);
+               }
+       }
+       if (list_empty(&c->free_list)) {
+               printk(KERN_DEBUG "free_list: empty\n");
+       } else {
+               struct list_head *this;
+
+               list_for_each(this, &c->free_list) {
+                       struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+                       printk(KERN_DEBUG "free_list: %08x\n", jeb->offset);
+               }
+       }
+       if (list_empty(&c->bad_list)) {
+               printk(KERN_DEBUG "bad_list: empty\n");
+       } else {
+               struct list_head *this;
+
+               list_for_each(this, &c->bad_list) {
+                       struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+                       printk(KERN_DEBUG "bad_list: %08x\n", jeb->offset);
+               }
+       }
+       if (list_empty(&c->bad_used_list)) {
+               printk(KERN_DEBUG "bad_used_list: empty\n");
+       } else {
+               struct list_head *this;
+
+               list_for_each(this, &c->bad_used_list) {
+                       struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+                       printk(KERN_DEBUG "bad_used_list: %08x\n", jeb->offset);
+               }
+       }
+#endif /* CONFIG_JFFS2_FS_DEBUG */
+
+       spin_unlock_bh(&c->erase_completion_lock);
+
+
+       return 0;
+}
+
+static struct super_block *jffs2_read_super(struct super_block *sb, void *data, int silent)
+{
+       struct jffs2_sb_info *c;
+       struct inode *root_i;
+       int i;
+
+       D1(printk(KERN_DEBUG "jffs2: read_super for device %s\n", kdevname(sb->s_dev)));
+
+       if (MAJOR(sb->s_dev) != MTD_BLOCK_MAJOR) {
+               if (!silent)
+                       printk(KERN_DEBUG "jffs2: attempt to mount non-MTD device %s\n", kdevname(sb->s_dev));
+               return NULL;
+       }
+
+       c = JFFS2_SB_INFO(sb);
+       memset(c, 0, sizeof(*c));
+       
+       c->mtd = get_mtd_device(NULL, MINOR(sb->s_dev));
+       if (!c->mtd) {
+               D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", MINOR(sb->s_dev)));
+               return NULL;
+       }
+       c->sector_size = c->mtd->erasesize;
+       c->free_size = c->flash_size = c->mtd->size;
+       c->nr_blocks = c->mtd->size / c->mtd->erasesize;
+       c->blocks = kmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks, GFP_KERNEL);
+       if (!c->blocks)
+               goto out_mtd;
+       for (i=0; i<c->nr_blocks; i++) {
+               INIT_LIST_HEAD(&c->blocks[i].list);
+               c->blocks[i].offset = i * c->sector_size;
+               c->blocks[i].free_size = c->sector_size;
+               c->blocks[i].dirty_size = 0;
+               c->blocks[i].used_size = 0;
+               c->blocks[i].first_node = NULL;
+               c->blocks[i].last_node = NULL;
+       }
+               
+       spin_lock_init(&c->nodelist_lock);
+       init_MUTEX(&c->alloc_sem);
+       init_waitqueue_head(&c->erase_wait);
+       spin_lock_init(&c->erase_completion_lock);
+       spin_lock_init(&c->inocache_lock);
+
+       INIT_LIST_HEAD(&c->clean_list);
+       INIT_LIST_HEAD(&c->dirty_list);
+       INIT_LIST_HEAD(&c->erasing_list);
+       INIT_LIST_HEAD(&c->erase_pending_list);
+       INIT_LIST_HEAD(&c->erase_complete_list);
+       INIT_LIST_HEAD(&c->free_list);
+       INIT_LIST_HEAD(&c->bad_list);
+       INIT_LIST_HEAD(&c->bad_used_list);
+       c->highest_ino = 1;
+
+       if (jffs2_build_filesystem(c)) {
+               D1(printk(KERN_DEBUG "build_fs failed\n"));
+               goto out_nodes;
+       }
+       sb->s_op = &jffs2_super_operations;
+
+       D1(printk(KERN_DEBUG "jffs2_read_super(): Getting root inode\n"));
+       root_i = iget(sb, 1);
+       if (is_bad_inode(root_i)) {
+               D1(printk(KERN_WARNING "get root inode failed\n"));
+               goto out_nodes;
+       }
+
+       D1(printk(KERN_DEBUG "jffs2_read_super(): d_alloc_root()\n"));
+       sb->s_root = d_alloc_root(root_i);
+       if (!sb->s_root)
+               goto out_root_i;
+
+#if LINUX_VERSION_CODE >= 0x20403
+       sb->s_maxbytes = 0xFFFFFFFF;
+#endif
+       sb->s_blocksize = PAGE_CACHE_SIZE;
+       sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+       sb->s_magic = JFFS2_SUPER_MAGIC;
+       if (!(sb->s_flags & MS_RDONLY))
+               jffs2_start_garbage_collect_thread(c);
+       return sb;
+
+ out_root_i:
+       iput(root_i);
+ out_nodes:
+       jffs2_free_ino_caches(c);
+       jffs2_free_raw_node_refs(c);
+       kfree(c->blocks);
+ out_mtd:
+       put_mtd_device(c->mtd);
+       return NULL;
+}
+
+void jffs2_put_super (struct super_block *sb)
+{
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
+
+       D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
+
+       if (!(sb->s_flags & MS_RDONLY))
+               jffs2_stop_garbage_collect_thread(c);
+       jffs2_free_ino_caches(c);
+       jffs2_free_raw_node_refs(c);
+       kfree(c->blocks);
+       if (c->mtd->sync)
+               c->mtd->sync(c->mtd);
+       put_mtd_device(c->mtd);
+       
+       D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
+}
+
+int jffs2_remount_fs (struct super_block *sb, int *flags, char *data)
+{
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
+
+       if (c->flags & JFFS2_SB_FLAG_RO && !(sb->s_flags & MS_RDONLY))
+               return -EROFS;
+
+       /* We stop if it was running, then restart if it needs to.
+          This also catches the case where it was stopped and this
+          is just a remount to restart it */
+       if (!(sb->s_flags & MS_RDONLY))
+               jffs2_stop_garbage_collect_thread(c);
+
+       if (!(*flags & MS_RDONLY))
+               jffs2_start_garbage_collect_thread(c);
+       
+       sb->s_flags = (sb->s_flags & ~MS_RDONLY)|(*flags & MS_RDONLY);
+
+       return 0;
+}
+
+void jffs2_write_super (struct super_block *sb)
+{
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
+       sb->s_dirt = 0;
+
+       if (sb->s_flags & MS_RDONLY)
+               return;
+
+       jffs2_garbage_collect_trigger(c);
+       jffs2_erase_pending_blocks(c);
+       jffs2_mark_erased_blocks(c);
+}
+
+
+static DECLARE_FSTYPE_DEV(jffs2_fs_type, "jffs2", jffs2_read_super);
+
+static int __init init_jffs2_fs(void)
+{
+       int ret;
+
+       printk(KERN_NOTICE "JFFS2 version 2.1. (C) 2001 Red Hat, Inc., designed by Axis Communications AB.\n");
+
+#ifdef JFFS2_OUT_OF_KERNEL
+       /* sanity checks. Could we do these at compile time? */
+       if (sizeof(struct jffs2_sb_info) > sizeof (((struct super_block *)NULL)->u)) {
+               printk(KERN_ERR "JFFS2 error: struct jffs2_sb_info (%d bytes) doesn't fit in the super_block union (%d bytes)\n", 
+                      sizeof(struct jffs2_sb_info), sizeof (((struct super_block *)NULL)->u));
+               return -EIO;
+       }
+
+       if (sizeof(struct jffs2_inode_info) > sizeof (((struct inode *)NULL)->u)) {
+               printk(KERN_ERR "JFFS2 error: struct jffs2_inode_info (%d bytes) doesn't fit in the inode union (%d bytes)\n", 
+                      sizeof(struct jffs2_inode_info), sizeof (((struct inode *)NULL)->u));
+               return -EIO;
+       }
+#endif
+
+       ret = jffs2_create_slab_caches();
+       if (ret) {
+               printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
+               return ret;
+       }
+       ret = register_filesystem(&jffs2_fs_type);
+       if (ret) {
+               printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
+               jffs2_destroy_slab_caches();
+       }
+       return ret;
+}
+
+static void __exit exit_jffs2_fs(void)
+{
+       jffs2_destroy_slab_caches();
+       unregister_filesystem(&jffs2_fs_type);
+}
+
+module_init(init_jffs2_fs);
+module_exit(exit_jffs2_fs);
+
+MODULE_DESCRIPTION("The Journalling Flash File System, v2");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for 
+                      // the sake of this tag. It's Free Software.
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
diff --git a/yaffsdev b/yaffsdev
new file mode 100755 (executable)
index 0000000..6e51051
Binary files /dev/null and b/yaffsdev differ
diff --git a/yaffsdev.c b/yaffsdev.c
new file mode 100644 (file)
index 0000000..64368f4
--- /dev/null
@@ -0,0 +1,303 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * yaffsdev.c
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include "yaffsinterface.h"
+#include "yaffs_nandemul.h" 
+#include "yaffs_guts.h"
+#include <stdlib.h>
+
+#include <stdio.h>
+#include <string.h>
+
+
+
+
+yaffs_Device device;
+
+
+
+
+
+
+
+char *testStr = "this is a test string";
+
+char *testStr2 = "abcdefghijklmnopqrstuvwxyz1234567890";
+
+void TestTimexxx(yaffs_Device *dev)
+{
+       yaffs_Object *f;
+       int x;
+       
+       
+       printf("Start\n");
+       
+
+       f = yaffs_FindObjectByName(yaffs_Root(dev),"Name1");
+       if(f)
+       {
+               printf("Found\n");
+       }
+       else
+       {
+               f = yaffs_MknodFile(yaffs_Root(dev),"Name1",0,0,0);
+               printf("Created\n");
+       }
+       
+       
+       x = yaffs_RenameObject(yaffs_Root(dev),"Name1",NULL,"Rename");
+               
+}
+
+
+void TestTimeasasas(yaffs_Device *dev)
+{
+       yaffs_Object *f; 
+       int x;
+       int i;
+       int b;
+       char data[200];
+       int written;
+       
+       
+       printf("Start\n");
+       
+
+       f = yaffs_FindObjectByName(yaffs_Root(dev),"Name1");
+       if(f)
+       {
+               printf("Found\n");
+       }
+       else
+       {
+               f = yaffs_MknodFile(yaffs_Root(dev),"Name1",0,0,0);
+               printf("Created\n");
+       }
+       
+       
+       x = yaffs_RenameObject(yaffs_Root(dev),"Name1",NULL,"Rename");
+       
+       
+       
+       for(i = 0; i < 10000; i+=20)
+       {
+       
+               b++;
+               if(b & 1)
+                       written = yaffs_WriteDataToFile(f,testStr,i,strlen(testStr));
+               else
+                       written = yaffs_WriteDataToFile(f,testStr2,i,strlen(testStr2));
+       }
+       
+       
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       printf("Flush\n");
+       
+       yaffs_FlushFile(f);
+
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       yaffs_ReadDataFromFile(f,data,1000,50);
+       data[50] = 0;
+       
+       printf("Read data is \"%s\"\n",data);
+       
+       yaffs_DumpObject(f);
+
+       printf("Resize\n");     
+       yaffs_ResizeFile(f,2000);
+       
+       yaffs_DumpObject(f);
+
+       yaffs_FlushFile(f);
+       
+       
+               
+
+}
+
+void TestTime(yaffs_Device *dev)
+{
+       yaffs_Object *f;
+       yaffs_Object *sl;
+       yaffs_Object *lnf;
+       
+       yaffs_Object *hl1;
+       yaffs_Object *hl2;
+       yaffs_Object *hl3;
+       yaffs_Object *d, *df;
+       
+       int x;
+       int i;
+       int b;
+       char data[200];
+       
+       char * alias;
+       int written;
+       
+       
+       printf("Start\n");
+       
+
+       f = yaffs_FindObjectByName(yaffs_Root(dev),"Name1");
+       if(f)
+       {
+               printf("Found\n");
+       }
+       else
+       {
+               f = yaffs_MknodFile(yaffs_Root(dev),"Name1",0,0,0);
+               printf("Created\n");
+       }
+       
+       
+       x = yaffs_RenameObject(yaffs_Root(dev),"Name1",NULL,"Rename");
+       
+       for(i = 0; i < 100000; i+=20)
+       {
+       
+               b++;
+               if(b & 1)
+                       written = yaffs_WriteDataToFile(f,testStr,i,strlen(testStr));
+               else
+                       written = yaffs_WriteDataToFile(f,testStr2,i,strlen(testStr2));
+       }
+       
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       printf("Flush\n");
+       
+       yaffs_FlushFile(f);
+       
+       printf("File length is %d\n",yaffs_GetObjectFileLength(f));
+       
+       sl = yaffs_MknodSymLink(yaffs_Root(dev),"sym-link",0,0,0,"/tmp/alias");
+
+
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       printf("\n\nsymlink alias is \"%s\"\n",alias = yaffs_GetSymlinkAlias(sl));
+       
+       free(alias);
+       
+       printf("Unlink symlink %d\n",yaffs_Unlink(yaffs_Root(dev),"sym-link"));
+       
+       
+       yaffs_ReadDataFromFile(f,data,1000,50);
+       data[50] = 0;
+       
+       printf("Read data is \"%s\"\n",data);
+       
+       yaffs_DumpObject(f);
+
+       printf("Resize\n");     
+       yaffs_ResizeFile(f,2000);
+       
+       yaffs_DumpObject(f);
+       
+       lnf = yaffs_FindObjectByName(yaffs_Root(dev),YAFFS_LOSTNFOUND_NAME);
+       
+       
+
+       yaffs_FlushFile(f);
+               
+
+       printf("Unlink file: %d\n",yaffs_Unlink(yaffs_Root(dev),"Rename"));
+       
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       // Create a directory and play with it
+       
+
+       printf("Create directory and play with it\n");
+               
+       d = yaffs_MknodDirectory(yaffs_Root(dev),"direct",0,0,0);
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       yaffs_ApplyToDirectoryChildren(d,yaffs_DumpObject);
+       
+       printf("Make file in directory\n");
+       
+       df = yaffs_MknodFile(d,"file-in-directory",0,0,0);
+       yaffs_ApplyToDirectoryChildren(d,yaffs_DumpObject);
+       
+       
+       // Do some stuff with hardlinks
+       //
+       // NB Deleting hardlinked objects can mess up pointers to hardlinks.
+       // The mechanism is as follows:
+       // * If you unlink a file,softlink or directory that has one or more hardlinks,
+       // then the object is renamed to one of the hardlinks and that hardlink is unlinked.
+       // This means that a pointer to a hardlink so deleted will point to an invalid address.
+       // Thus, make sure that pointers to hardlinks are immediately dereferenced.
+
+
+       printf("Hard link tests\n");
+               
+       f = yaffs_MknodFile(yaffs_Root(dev),"Name1",0,0,0);
+       hl1 = yaffs_Link(yaffs_Root(dev),"HardLink 1",f);
+       hl2 = yaffs_Link(yaffs_Root(dev),"HardLink 2",f);
+       hl3 = yaffs_Link(yaffs_Root(dev),"HardLink 3",hl2);
+
+       printf("\n\nHard links created\n");
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       yaffs_Unlink(yaffs_Root(dev),"HardLink 1");
+       printf("\n\nHard link deleted\n");
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       yaffs_Unlink(yaffs_Root(dev),"Name1");
+       printf("\n\nHard linked file deleted\n");
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       yaffs_Unlink(yaffs_Root(dev),"HardLink 2");
+       printf("\n\nHard link 2 deleted\n");
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       yaffs_Unlink(yaffs_Root(dev),"HardLink 3");
+
+       printf("\n\nHard link 3 deleted\n");
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+       
+       // NB We don't allow unlinking or rename of the root or lost+found
+       // We allow setting attributes, but these must not be written to
+       // NAND since they are not real objects.
+       
+       printf("Attempt to rename lost+found - should have failed\n");
+       x = yaffs_RenameObject(yaffs_Root(dev),YAFFS_LOSTNFOUND_NAME,NULL,"Renamed");
+       yaffs_ApplyToDirectoryChildren(yaffs_Root(dev),yaffs_DumpObject);
+
+}
+
+int main(int argc,char *argv[])
+{
+       device.nBlocks = (2 * 1024 * 1024) / (YAFFS_CHUNKS_PER_BLOCK * YAFFS_BYTES_PER_CHUNK);
+       device.startBlock = 1;  // Don't use block 0
+       device.endBlock = device.nBlocks - 1;
+       
+       device.writeChunkToNAND = nandemul_WriteChunkToNAND;
+       device.readChunkFromNAND = nandemul_ReadChunkFromNAND;
+       device.eraseBlockInNAND = nandemul_EraseBlockInNAND;
+       device.initialiseNAND = nandemul_InitialiseNAND;
+       
+       yaffs_GutsInitialise(&device);
+       
+       // yaffs_GutsTest();
+       
+       TestTime(&device);
+       
+       exit(0);
+}
diff --git a/yaffsdev.proj b/yaffsdev.proj
new file mode 100644 (file)
index 0000000..2335511
Binary files /dev/null and b/yaffsdev.proj differ
diff --git a/yaffsinterface.h b/yaffsinterface.h
new file mode 100644 (file)
index 0000000..972a04d
--- /dev/null
@@ -0,0 +1,23 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system.
+ * yaffsinterface.h: Interface to the guts of yaffs.
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#ifndef __YAFFSINTERFACE_H__
+#define __YAFFSINTERFACE_H__
+
+
+int yaffs_Initialise(unsigned nBlocks);
+
+#endif
+
diff --git a/yportenv.h b/yportenv.h
new file mode 100644 (file)
index 0000000..fc84fc5
--- /dev/null
@@ -0,0 +1,56 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ * yportenv.h: Portable services used by yaffs. This is done to allow
+ * simple migration from kernel space into app space for testing.
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#ifndef __PORTENV_H__
+#define __PORTENV_H__
+
+#ifndef __KERNEL__
+
+#include "stdlib.h"
+#include "stdio.h"
+#include "string.h"
+
+#define YPRINTF(x) printf x
+#define YMALLOC(x) malloc(x)
+#define YFREE(x)   free(x)
+
+
+#define YINFO(s) YPRINTF(( __FILE__ " %d %s\n",__LINE__,s))
+#define YALERT(s) YINFO(s)
+
+#else
+
+#include "linux/kernel.h"
+#include "linux/mm.h"
+#include "linux/string.h"
+#include "linux/slab.h"
+
+#define YPRINTF(x) printk x
+#define YMALLOC(x) kmalloc(x,GFP_KERNEL)
+#define YFREE(x)   kfree(x)
+
+#endif
+
+
+
+#define YINFO(s) YPRINTF((KERN_DEBUG __FILE__ " %d %s\n",__LINE__,s))
+#define YALERT(s) YINFO(s)
+
+#endif
+
+
+
+