Further extensions for VxWorks wrapper
[yaffs2.git] / yaffs_guts.c
1 /*
2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
3  *
4  * Copyright (C) 2002-2011 Aleph One Ltd.
5  *   for Toby Churchill Ltd and Brightstar Engineering
6  *
7  * Created by Charles Manning <charles@aleph1.co.uk>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13
14 #include "yportenv.h"
15 #include "yaffs_trace.h"
16
17 #include "yaffs_guts.h"
18 #include "yaffs_getblockinfo.h"
19 #include "yaffs_tagscompat.h"
20 #include "yaffs_tagsmarshall.h"
21 #include "yaffs_nand.h"
22 #include "yaffs_yaffs1.h"
23 #include "yaffs_yaffs2.h"
24 #include "yaffs_bitmap.h"
25 #include "yaffs_verify.h"
26 #include "yaffs_nand.h"
27 #include "yaffs_packedtags2.h"
28 #include "yaffs_nameval.h"
29 #include "yaffs_allocator.h"
30 #include "yaffs_attribs.h"
31 #include "yaffs_summary.h"
32
33 /* Note YAFFS_GC_GOOD_ENOUGH must be <= YAFFS_GC_PASSIVE_THRESHOLD */
34 #define YAFFS_GC_GOOD_ENOUGH 2
35 #define YAFFS_GC_PASSIVE_THRESHOLD 4
36
37 #include "yaffs_ecc.h"
38
39 /* Forward declarations */
40
41 static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
42                              const u8 *buffer, int n_bytes, int use_reserve);
43
44 static void yaffs_fix_null_name(struct yaffs_obj *obj, YCHAR *name,
45                                 int buffer_size);
46
47 /* Function to calculate chunk and offset */
48
49 void yaffs_addr_to_chunk(struct yaffs_dev *dev, loff_t addr,
50                                 int *chunk_out, u32 *offset_out)
51 {
52         int chunk;
53         u32 offset;
54
55         chunk = (u32) (addr >> dev->chunk_shift);
56
57         if (dev->chunk_div == 1) {
58                 /* easy power of 2 case */
59                 offset = (u32) (addr & dev->chunk_mask);
60         } else {
61                 /* Non power-of-2 case */
62
63                 loff_t chunk_base;
64
65                 chunk /= dev->chunk_div;
66
67                 chunk_base = ((loff_t) chunk) * dev->data_bytes_per_chunk;
68                 offset = (u32) (addr - chunk_base);
69         }
70
71         *chunk_out = chunk;
72         *offset_out = offset;
73 }
74
75 /* Function to return the number of shifts for a power of 2 greater than or
76  * equal to the given number
77  * Note we don't try to cater for all possible numbers and this does not have to
78  * be hellishly efficient.
79  */
80
81 static inline u32 calc_shifts_ceiling(u32 x)
82 {
83         int extra_bits;
84         int shifts;
85
86         shifts = extra_bits = 0;
87
88         while (x > 1) {
89                 if (x & 1)
90                         extra_bits++;
91                 x >>= 1;
92                 shifts++;
93         }
94
95         if (extra_bits)
96                 shifts++;
97
98         return shifts;
99 }
100
101 /* Function to return the number of shifts to get a 1 in bit 0
102  */
103
104 static inline u32 calc_shifts(u32 x)
105 {
106         u32 shifts;
107
108         shifts = 0;
109
110         if (!x)
111                 return 0;
112
113         while (!(x & 1)) {
114                 x >>= 1;
115                 shifts++;
116         }
117
118         return shifts;
119 }
120
121 /*
122  * Temporary buffer manipulations.
123  */
124
125 static int yaffs_init_tmp_buffers(struct yaffs_dev *dev)
126 {
127         int i;
128         u8 *buf = (u8 *) 1;
129
130         memset(dev->temp_buffer, 0, sizeof(dev->temp_buffer));
131
132         for (i = 0; buf && i < YAFFS_N_TEMP_BUFFERS; i++) {
133                 dev->temp_buffer[i].in_use = 0;
134                 buf = kmalloc(dev->param.total_bytes_per_chunk, GFP_NOFS);
135                 dev->temp_buffer[i].buffer = buf;
136         }
137
138         return buf ? YAFFS_OK : YAFFS_FAIL;
139 }
140
141 u8 *yaffs_get_temp_buffer(struct yaffs_dev * dev)
142 {
143         int i;
144
145         dev->temp_in_use++;
146         if (dev->temp_in_use > dev->max_temp)
147                 dev->max_temp = dev->temp_in_use;
148
149         for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
150                 if (dev->temp_buffer[i].in_use == 0) {
151                         dev->temp_buffer[i].in_use = 1;
152                         return dev->temp_buffer[i].buffer;
153                 }
154         }
155
156         yaffs_trace(YAFFS_TRACE_BUFFERS, "Out of temp buffers");
157         /*
158          * If we got here then we have to allocate an unmanaged one
159          * This is not good.
160          */
161
162         dev->unmanaged_buffer_allocs++;
163         return kmalloc(dev->data_bytes_per_chunk, GFP_NOFS);
164
165 }
166
167 void yaffs_release_temp_buffer(struct yaffs_dev *dev, u8 *buffer)
168 {
169         int i;
170
171         dev->temp_in_use--;
172
173         for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
174                 if (dev->temp_buffer[i].buffer == buffer) {
175                         dev->temp_buffer[i].in_use = 0;
176                         return;
177                 }
178         }
179
180         if (buffer) {
181                 /* assume it is an unmanaged one. */
182                 yaffs_trace(YAFFS_TRACE_BUFFERS,
183                         "Releasing unmanaged temp buffer");
184                 kfree(buffer);
185                 dev->unmanaged_buffer_deallocs++;
186         }
187
188 }
189
190 /*
191  * Functions for robustisizing TODO
192  *
193  */
194
195 static void yaffs_handle_chunk_wr_ok(struct yaffs_dev *dev, int nand_chunk,
196                                      const u8 *data,
197                                      const struct yaffs_ext_tags *tags)
198 {
199         (void) dev;
200         (void) nand_chunk;
201         (void) data;
202         (void) tags;
203 }
204
205 static void yaffs_handle_chunk_update(struct yaffs_dev *dev, int nand_chunk,
206                                       const struct yaffs_ext_tags *tags)
207 {
208         (void) dev;
209         (void) nand_chunk;
210         (void) tags;
211 }
212
213 void yaffs_handle_chunk_error(struct yaffs_dev *dev,
214                               struct yaffs_block_info *bi)
215 {
216         if (!bi->gc_prioritise) {
217                 bi->gc_prioritise = 1;
218                 dev->has_pending_prioritised_gc = 1;
219                 bi->chunk_error_strikes++;
220
221                 if (bi->chunk_error_strikes > 3) {
222                         bi->needs_retiring = 1; /* Too many stikes, so retire */
223                         yaffs_trace(YAFFS_TRACE_ALWAYS,
224                                 "yaffs: Block struck out");
225
226                 }
227         }
228 }
229
230 static void yaffs_handle_chunk_wr_error(struct yaffs_dev *dev, int nand_chunk,
231                                         int erased_ok)
232 {
233         int flash_block = nand_chunk / dev->param.chunks_per_block;
234         struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);
235
236         yaffs_handle_chunk_error(dev, bi);
237
238         if (erased_ok) {
239                 /* Was an actual write failure,
240                  * so mark the block for retirement.*/
241                 bi->needs_retiring = 1;
242                 yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
243                   "**>> Block %d needs retiring", flash_block);
244         }
245
246         /* Delete the chunk */
247         yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
248         yaffs_skip_rest_of_block(dev);
249 }
250
251 /*
252  * Verification code
253  */
254
255 /*
256  *  Simple hash function. Needs to have a reasonable spread
257  */
258
259 static inline int yaffs_hash_fn(int n)
260 {
261         if (n < 0)
262                 n = -n;
263         return n % YAFFS_NOBJECT_BUCKETS;
264 }
265
266 /*
267  * Access functions to useful fake objects.
268  * Note that root might have a presence in NAND if permissions are set.
269  */
270
271 struct yaffs_obj *yaffs_root(struct yaffs_dev *dev)
272 {
273         return dev->root_dir;
274 }
275
276 struct yaffs_obj *yaffs_lost_n_found(struct yaffs_dev *dev)
277 {
278         return dev->lost_n_found;
279 }
280
281 /*
282  *  Erased NAND checking functions
283  */
284
285 int yaffs_check_ff(u8 *buffer, int n_bytes)
286 {
287         /* Horrible, slow implementation */
288         while (n_bytes--) {
289                 if (*buffer != 0xff)
290                         return 0;
291                 buffer++;
292         }
293         return 1;
294 }
295
296 static int yaffs_check_chunk_erased(struct yaffs_dev *dev, int nand_chunk)
297 {
298         int retval = YAFFS_OK;
299         u8 *data = yaffs_get_temp_buffer(dev);
300         struct yaffs_ext_tags tags;
301         int result;
302
303         result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, data, &tags);
304
305         if (tags.ecc_result > YAFFS_ECC_RESULT_NO_ERROR)
306                 retval = YAFFS_FAIL;
307
308         if (!yaffs_check_ff(data, dev->data_bytes_per_chunk) ||
309                 tags.chunk_used) {
310                 yaffs_trace(YAFFS_TRACE_NANDACCESS,
311                         "Chunk %d not erased", nand_chunk);
312                 retval = YAFFS_FAIL;
313         }
314
315         yaffs_release_temp_buffer(dev, data);
316
317         return retval;
318
319 }
320
321 static int yaffs_verify_chunk_written(struct yaffs_dev *dev,
322                                       int nand_chunk,
323                                       const u8 *data,
324                                       struct yaffs_ext_tags *tags)
325 {
326         int retval = YAFFS_OK;
327         struct yaffs_ext_tags temp_tags;
328         u8 *buffer = yaffs_get_temp_buffer(dev);
329         int result;
330
331         result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, buffer, &temp_tags);
332         if (memcmp(buffer, data, dev->data_bytes_per_chunk) ||
333             temp_tags.obj_id != tags->obj_id ||
334             temp_tags.chunk_id != tags->chunk_id ||
335             temp_tags.n_bytes != tags->n_bytes)
336                 retval = YAFFS_FAIL;
337
338         yaffs_release_temp_buffer(dev, buffer);
339
340         return retval;
341 }
342
343
344 int yaffs_check_alloc_available(struct yaffs_dev *dev, int n_chunks)
345 {
346         int reserved_chunks;
347         int reserved_blocks = dev->param.n_reserved_blocks;
348         int checkpt_blocks;
349
350         checkpt_blocks = yaffs_calc_checkpt_blocks_required(dev);
351
352         reserved_chunks =
353             (reserved_blocks + checkpt_blocks) * dev->param.chunks_per_block;
354
355         return (dev->n_free_chunks > (reserved_chunks + n_chunks));
356 }
357
358 static int yaffs_find_alloc_block(struct yaffs_dev *dev)
359 {
360         int i;
361         struct yaffs_block_info *bi;
362
363         if (dev->n_erased_blocks < 1) {
364                 /* Hoosterman we've got a problem.
365                  * Can't get space to gc
366                  */
367                 yaffs_trace(YAFFS_TRACE_ERROR,
368                   "yaffs tragedy: no more erased blocks");
369
370                 return -1;
371         }
372
373         /* Find an empty block. */
374
375         for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
376                 dev->alloc_block_finder++;
377                 if (dev->alloc_block_finder < dev->internal_start_block
378                     || dev->alloc_block_finder > dev->internal_end_block) {
379                         dev->alloc_block_finder = dev->internal_start_block;
380                 }
381
382                 bi = yaffs_get_block_info(dev, dev->alloc_block_finder);
383
384                 if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
385                         bi->block_state = YAFFS_BLOCK_STATE_ALLOCATING;
386                         dev->seq_number++;
387                         bi->seq_number = dev->seq_number;
388                         dev->n_erased_blocks--;
389                         yaffs_trace(YAFFS_TRACE_ALLOCATE,
390                           "Allocated block %d, seq  %d, %d left" ,
391                            dev->alloc_block_finder, dev->seq_number,
392                            dev->n_erased_blocks);
393                         return dev->alloc_block_finder;
394                 }
395         }
396
397         yaffs_trace(YAFFS_TRACE_ALWAYS,
398                 "yaffs tragedy: no more erased blocks, but there should have been %d",
399                 dev->n_erased_blocks);
400
401         return -1;
402 }
403
404 static int yaffs_alloc_chunk(struct yaffs_dev *dev, int use_reserver,
405                              struct yaffs_block_info **block_ptr)
406 {
407         int ret_val;
408         struct yaffs_block_info *bi;
409
410         if (dev->alloc_block < 0) {
411                 /* Get next block to allocate off */
412                 dev->alloc_block = yaffs_find_alloc_block(dev);
413                 dev->alloc_page = 0;
414         }
415
416         if (!use_reserver && !yaffs_check_alloc_available(dev, 1)) {
417                 /* No space unless we're allowed to use the reserve. */
418                 return -1;
419         }
420
421         if (dev->n_erased_blocks < dev->param.n_reserved_blocks
422             && dev->alloc_page == 0)
423                 yaffs_trace(YAFFS_TRACE_ALLOCATE, "Allocating reserve");
424
425         /* Next page please.... */
426         if (dev->alloc_block >= 0) {
427                 bi = yaffs_get_block_info(dev, dev->alloc_block);
428
429                 ret_val = (dev->alloc_block * dev->param.chunks_per_block) +
430                     dev->alloc_page;
431                 bi->pages_in_use++;
432                 yaffs_set_chunk_bit(dev, dev->alloc_block, dev->alloc_page);
433
434                 dev->alloc_page++;
435
436                 dev->n_free_chunks--;
437
438                 /* If the block is full set the state to full */
439                 if (dev->alloc_page >= dev->param.chunks_per_block) {
440                         bi->block_state = YAFFS_BLOCK_STATE_FULL;
441                         dev->alloc_block = -1;
442                 }
443
444                 if (block_ptr)
445                         *block_ptr = bi;
446
447                 return ret_val;
448         }
449
450         yaffs_trace(YAFFS_TRACE_ERROR,
451                 "!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!");
452
453         return -1;
454 }
455
456 static int yaffs_get_erased_chunks(struct yaffs_dev *dev)
457 {
458         int n;
459
460         n = dev->n_erased_blocks * dev->param.chunks_per_block;
461
462         if (dev->alloc_block > 0)
463                 n += (dev->param.chunks_per_block - dev->alloc_page);
464
465         return n;
466
467 }
468
469 /*
470  * yaffs_skip_rest_of_block() skips over the rest of the allocation block
471  * if we don't want to write to it.
472  */
473 void yaffs_skip_rest_of_block(struct yaffs_dev *dev)
474 {
475         struct yaffs_block_info *bi;
476
477         if (dev->alloc_block > 0) {
478                 bi = yaffs_get_block_info(dev, dev->alloc_block);
479                 if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING) {
480                         bi->block_state = YAFFS_BLOCK_STATE_FULL;
481                         dev->alloc_block = -1;
482                 }
483         }
484 }
485
486 static int yaffs_write_new_chunk(struct yaffs_dev *dev,
487                                  const u8 *data,
488                                  struct yaffs_ext_tags *tags, int use_reserver)
489 {
490         int attempts = 0;
491         int write_ok = 0;
492         int chunk;
493
494         yaffs2_checkpt_invalidate(dev);
495
496         do {
497                 struct yaffs_block_info *bi = 0;
498                 int erased_ok = 0;
499
500                 chunk = yaffs_alloc_chunk(dev, use_reserver, &bi);
501                 if (chunk < 0) {
502                         /* no space */
503                         break;
504                 }
505
506                 /* First check this chunk is erased, if it needs
507                  * checking.  The checking policy (unless forced
508                  * always on) is as follows:
509                  *
510                  * Check the first page we try to write in a block.
511                  * If the check passes then we don't need to check any
512                  * more.        If the check fails, we check again...
513                  * If the block has been erased, we don't need to check.
514                  *
515                  * However, if the block has been prioritised for gc,
516                  * then we think there might be something odd about
517                  * this block and stop using it.
518                  *
519                  * Rationale: We should only ever see chunks that have
520                  * not been erased if there was a partially written
521                  * chunk due to power loss.  This checking policy should
522                  * catch that case with very few checks and thus save a
523                  * lot of checks that are most likely not needed.
524                  *
525                  * Mods to the above
526                  * If an erase check fails or the write fails we skip the
527                  * rest of the block.
528                  */
529
530                 /* let's give it a try */
531                 attempts++;
532
533                 if (dev->param.always_check_erased)
534                         bi->skip_erased_check = 0;
535
536                 if (!bi->skip_erased_check) {
537                         erased_ok = yaffs_check_chunk_erased(dev, chunk);
538                         if (erased_ok != YAFFS_OK) {
539                                 yaffs_trace(YAFFS_TRACE_ERROR,
540                                   "**>> yaffs chunk %d was not erased",
541                                   chunk);
542
543                                 /* If not erased, delete this one,
544                                  * skip rest of block and
545                                  * try another chunk */
546                                 yaffs_chunk_del(dev, chunk, 1, __LINE__);
547                                 yaffs_skip_rest_of_block(dev);
548                                 continue;
549                         }
550                 }
551
552                 write_ok = yaffs_wr_chunk_tags_nand(dev, chunk, data, tags);
553
554                 if (!bi->skip_erased_check)
555                         write_ok =
556                             yaffs_verify_chunk_written(dev, chunk, data, tags);
557
558                 if (write_ok != YAFFS_OK) {
559                         /* Clean up aborted write, skip to next block and
560                          * try another chunk */
561                         yaffs_handle_chunk_wr_error(dev, chunk, erased_ok);
562                         continue;
563                 }
564
565                 bi->skip_erased_check = 1;
566
567                 /* Copy the data into the robustification buffer */
568                 yaffs_handle_chunk_wr_ok(dev, chunk, data, tags);
569
570         } while (write_ok != YAFFS_OK &&
571                  (yaffs_wr_attempts <= 0 || attempts <= yaffs_wr_attempts));
572
573         if (!write_ok)
574                 chunk = -1;
575
576         if (attempts > 1) {
577                 yaffs_trace(YAFFS_TRACE_ERROR,
578                         "**>> yaffs write required %d attempts",
579                         attempts);
580                 dev->n_retried_writes += (attempts - 1);
581         }
582
583         return chunk;
584 }
585
586 /*
587  * Block retiring for handling a broken block.
588  */
589
590 static void yaffs_retire_block(struct yaffs_dev *dev, int flash_block)
591 {
592         struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);
593
594         yaffs2_checkpt_invalidate(dev);
595
596         yaffs2_clear_oldest_dirty_seq(dev, bi);
597
598         if (yaffs_mark_bad(dev, flash_block) != YAFFS_OK) {
599                 if (yaffs_erase_block(dev, flash_block) != YAFFS_OK) {
600                         yaffs_trace(YAFFS_TRACE_ALWAYS,
601                                 "yaffs: Failed to mark bad and erase block %d",
602                                 flash_block);
603                 } else {
604                         struct yaffs_ext_tags tags;
605                         int chunk_id =
606                             flash_block * dev->param.chunks_per_block;
607
608                         u8 *buffer = yaffs_get_temp_buffer(dev);
609
610                         memset(buffer, 0xff, dev->data_bytes_per_chunk);
611                         memset(&tags, 0, sizeof(tags));
612                         tags.seq_number = YAFFS_SEQUENCE_BAD_BLOCK;
613                         if (dev->tagger.write_chunk_tags_fn(dev, chunk_id -
614                                                         dev->chunk_offset,
615                                                         buffer,
616                                                         &tags) != YAFFS_OK)
617                                 yaffs_trace(YAFFS_TRACE_ALWAYS,
618                                         "yaffs: Failed to write bad block marker to block %d",
619                                         flash_block);
620
621                         yaffs_release_temp_buffer(dev, buffer);
622                 }
623         }
624
625         bi->block_state = YAFFS_BLOCK_STATE_DEAD;
626         bi->gc_prioritise = 0;
627         bi->needs_retiring = 0;
628
629         dev->n_retired_blocks++;
630 }
631
632 /*---------------- Name handling functions ------------*/
633
634 static void yaffs_load_name_from_oh(struct yaffs_dev *dev, YCHAR *name,
635                                     const YCHAR *oh_name, int buff_size)
636 {
637 #ifdef CONFIG_YAFFS_AUTO_UNICODE
638         if (dev->param.auto_unicode) {
639                 if (*oh_name) {
640                         /* It is an ASCII name, do an ASCII to
641                          * unicode conversion */
642                         const char *ascii_oh_name = (const char *)oh_name;
643                         int n = buff_size - 1;
644                         while (n > 0 && *ascii_oh_name) {
645                                 *name = *ascii_oh_name;
646                                 name++;
647                                 ascii_oh_name++;
648                                 n--;
649                         }
650                 } else {
651                         strncpy(name, oh_name + 1, buff_size - 1);
652                 }
653         } else {
654 #else
655         (void) dev;
656         {
657 #endif
658                 strncpy(name, oh_name, buff_size - 1);
659         }
660 }
661
662 static void yaffs_load_oh_from_name(struct yaffs_dev *dev, YCHAR *oh_name,
663                                     const YCHAR *name)
664 {
665 #ifdef CONFIG_YAFFS_AUTO_UNICODE
666
667         int is_ascii;
668         const YCHAR *w;
669
670         if (dev->param.auto_unicode) {
671
672                 is_ascii = 1;
673                 w = name;
674
675                 /* Figure out if the name will fit in ascii character set */
676                 while (is_ascii && *w) {
677                         if ((*w) & 0xff00)
678                                 is_ascii = 0;
679                         w++;
680                 }
681
682                 if (is_ascii) {
683                         /* It is an ASCII name, so convert unicode to ascii */
684                         char *ascii_oh_name = (char *)oh_name;
685                         int n = YAFFS_MAX_NAME_LENGTH - 1;
686                         while (n > 0 && *name) {
687                                 *ascii_oh_name = *name;
688                                 name++;
689                                 ascii_oh_name++;
690                                 n--;
691                         }
692                 } else {
693                         /* Unicode name, so save starting at the second YCHAR */
694                         *oh_name = 0;
695                         strncpy(oh_name + 1, name, YAFFS_MAX_NAME_LENGTH - 2);
696                 }
697         } else {
698 #else
699         dev = dev;
700         {
701 #endif
702                 strncpy(oh_name, name, YAFFS_MAX_NAME_LENGTH - 1);
703         }
704 }
705
706 static u16 yaffs_calc_name_sum(const YCHAR *name)
707 {
708         u16 sum = 0;
709         u16 i = 1;
710
711         if (!name)
712                 return 0;
713
714         while ((*name) && i < (YAFFS_MAX_NAME_LENGTH / 2)) {
715
716                 /* 0x1f mask is case insensitive */
717                 sum += ((*name) & 0x1f) * i;
718                 i++;
719                 name++;
720         }
721         return sum;
722 }
723
724
725 void yaffs_set_obj_name(struct yaffs_obj *obj, const YCHAR * name)
726 {
727         memset(obj->short_name, 0, sizeof(obj->short_name));
728
729         if (name && !name[0]) {
730                 yaffs_fix_null_name(obj, obj->short_name,
731                                 YAFFS_SHORT_NAME_LENGTH);
732                 name = obj->short_name;
733         } else if (name &&
734                 strnlen(name, YAFFS_SHORT_NAME_LENGTH + 1) <=
735                 YAFFS_SHORT_NAME_LENGTH)  {
736                 strcpy(obj->short_name, name);
737         }
738
739         obj->sum = yaffs_calc_name_sum(name);
740 }
741
742 void yaffs_set_obj_name_from_oh(struct yaffs_obj *obj,
743                                 const struct yaffs_obj_hdr *oh)
744 {
745 #ifdef CONFIG_YAFFS_AUTO_UNICODE
746         YCHAR tmp_name[YAFFS_MAX_NAME_LENGTH + 1];
747         memset(tmp_name, 0, sizeof(tmp_name));
748         yaffs_load_name_from_oh(obj->my_dev, tmp_name, oh->name,
749                                 YAFFS_MAX_NAME_LENGTH + 1);
750         yaffs_set_obj_name(obj, tmp_name);
751 #else
752         yaffs_set_obj_name(obj, oh->name);
753 #endif
754 }
755
756 loff_t yaffs_max_file_size(struct yaffs_dev *dev)
757 {
758         if(sizeof(loff_t) < 8)
759                 return YAFFS_MAX_FILE_SIZE_32;
760         else
761                 return ((loff_t) YAFFS_MAX_CHUNK_ID) * dev->data_bytes_per_chunk;
762 }
763
764 /*-------------------- TNODES -------------------
765
766  * List of spare tnodes
767  * The list is hooked together using the first pointer
768  * in the tnode.
769  */
770
771 struct yaffs_tnode *yaffs_get_tnode(struct yaffs_dev *dev)
772 {
773         struct yaffs_tnode *tn = yaffs_alloc_raw_tnode(dev);
774
775         if (tn) {
776                 memset(tn, 0, dev->tnode_size);
777                 dev->n_tnodes++;
778         }
779
780         dev->checkpoint_blocks_required = 0;    /* force recalculation */
781
782         return tn;
783 }
784
785 /* FreeTnode frees up a tnode and puts it back on the free list */
786 static void yaffs_free_tnode(struct yaffs_dev *dev, struct yaffs_tnode *tn)
787 {
788         yaffs_free_raw_tnode(dev, tn);
789         dev->n_tnodes--;
790         dev->checkpoint_blocks_required = 0;    /* force recalculation */
791 }
792
793 static void yaffs_deinit_tnodes_and_objs(struct yaffs_dev *dev)
794 {
795         yaffs_deinit_raw_tnodes_and_objs(dev);
796         dev->n_obj = 0;
797         dev->n_tnodes = 0;
798 }
799
800 static void yaffs_load_tnode_0(struct yaffs_dev *dev, struct yaffs_tnode *tn,
801                         unsigned pos, unsigned val)
802 {
803         u32 *map = (u32 *) tn;
804         u32 bit_in_map;
805         u32 bit_in_word;
806         u32 word_in_map;
807         u32 mask;
808
809         pos &= YAFFS_TNODES_LEVEL0_MASK;
810         val >>= dev->chunk_grp_bits;
811
812         bit_in_map = pos * dev->tnode_width;
813         word_in_map = bit_in_map / 32;
814         bit_in_word = bit_in_map & (32 - 1);
815
816         mask = dev->tnode_mask << bit_in_word;
817
818         map[word_in_map] &= ~mask;
819         map[word_in_map] |= (mask & (val << bit_in_word));
820
821         if (dev->tnode_width > (32 - bit_in_word)) {
822                 bit_in_word = (32 - bit_in_word);
823                 word_in_map++;
824                 mask =
825                     dev->tnode_mask >> bit_in_word;
826                 map[word_in_map] &= ~mask;
827                 map[word_in_map] |= (mask & (val >> bit_in_word));
828         }
829 }
830
831 u32 yaffs_get_group_base(struct yaffs_dev *dev, struct yaffs_tnode *tn,
832                          unsigned pos)
833 {
834         u32 *map = (u32 *) tn;
835         u32 bit_in_map;
836         u32 bit_in_word;
837         u32 word_in_map;
838         u32 val;
839
840         pos &= YAFFS_TNODES_LEVEL0_MASK;
841
842         bit_in_map = pos * dev->tnode_width;
843         word_in_map = bit_in_map / 32;
844         bit_in_word = bit_in_map & (32 - 1);
845
846         val = map[word_in_map] >> bit_in_word;
847
848         if (dev->tnode_width > (32 - bit_in_word)) {
849                 bit_in_word = (32 - bit_in_word);
850                 word_in_map++;
851                 val |= (map[word_in_map] << bit_in_word);
852         }
853
854         val &= dev->tnode_mask;
855         val <<= dev->chunk_grp_bits;
856
857         return val;
858 }
859
860 /* ------------------- End of individual tnode manipulation -----------------*/
861
862 /* ---------Functions to manipulate the look-up tree (made up of tnodes) ------
863  * The look up tree is represented by the top tnode and the number of top_level
864  * in the tree. 0 means only the level 0 tnode is in the tree.
865  */
866
867 /* FindLevel0Tnode finds the level 0 tnode, if one exists. */
868 struct yaffs_tnode *yaffs_find_tnode_0(struct yaffs_dev *dev,
869                                        struct yaffs_file_var *file_struct,
870                                        u32 chunk_id)
871 {
872         struct yaffs_tnode *tn = file_struct->top;
873         u32 i;
874         int required_depth;
875         int level = file_struct->top_level;
876
877         (void) dev;
878
879         /* Check sane level and chunk Id */
880         if (level < 0 || level > YAFFS_TNODES_MAX_LEVEL)
881                 return NULL;
882
883         if (chunk_id > YAFFS_MAX_CHUNK_ID)
884                 return NULL;
885
886         /* First check we're tall enough (ie enough top_level) */
887
888         i = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
889         required_depth = 0;
890         while (i) {
891                 i >>= YAFFS_TNODES_INTERNAL_BITS;
892                 required_depth++;
893         }
894
895         if (required_depth > file_struct->top_level)
896                 return NULL;    /* Not tall enough, so we can't find it */
897
898         /* Traverse down to level 0 */
899         while (level > 0 && tn) {
900                 tn = tn->internal[(chunk_id >>
901                                    (YAFFS_TNODES_LEVEL0_BITS +
902                                     (level - 1) *
903                                     YAFFS_TNODES_INTERNAL_BITS)) &
904                                   YAFFS_TNODES_INTERNAL_MASK];
905                 level--;
906         }
907
908         return tn;
909 }
910
911 /* add_find_tnode_0 finds the level 0 tnode if it exists,
912  * otherwise first expands the tree.
913  * This happens in two steps:
914  *  1. If the tree isn't tall enough, then make it taller.
915  *  2. Scan down the tree towards the level 0 tnode adding tnodes if required.
916  *
917  * Used when modifying the tree.
918  *
919  *  If the tn argument is NULL, then a fresh tnode will be added otherwise the
920  *  specified tn will be plugged into the ttree.
921  */
922
923 struct yaffs_tnode *yaffs_add_find_tnode_0(struct yaffs_dev *dev,
924                                            struct yaffs_file_var *file_struct,
925                                            u32 chunk_id,
926                                            struct yaffs_tnode *passed_tn)
927 {
928         int required_depth;
929         int i;
930         int l;
931         struct yaffs_tnode *tn;
932         u32 x;
933
934         /* Check sane level and page Id */
935         if (file_struct->top_level < 0 ||
936             file_struct->top_level > YAFFS_TNODES_MAX_LEVEL)
937                 return NULL;
938
939         if (chunk_id > YAFFS_MAX_CHUNK_ID)
940                 return NULL;
941
942         /* First check we're tall enough (ie enough top_level) */
943
944         x = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
945         required_depth = 0;
946         while (x) {
947                 x >>= YAFFS_TNODES_INTERNAL_BITS;
948                 required_depth++;
949         }
950
951         if (required_depth > file_struct->top_level) {
952                 /* Not tall enough, gotta make the tree taller */
953                 for (i = file_struct->top_level; i < required_depth; i++) {
954
955                         tn = yaffs_get_tnode(dev);
956
957                         if (tn) {
958                                 tn->internal[0] = file_struct->top;
959                                 file_struct->top = tn;
960                                 file_struct->top_level++;
961                         } else {
962                                 yaffs_trace(YAFFS_TRACE_ERROR,
963                                         "yaffs: no more tnodes");
964                                 return NULL;
965                         }
966                 }
967         }
968
969         /* Traverse down to level 0, adding anything we need */
970
971         l = file_struct->top_level;
972         tn = file_struct->top;
973
974         if (l > 0) {
975                 while (l > 0 && tn) {
976                         x = (chunk_id >>
977                              (YAFFS_TNODES_LEVEL0_BITS +
978                               (l - 1) * YAFFS_TNODES_INTERNAL_BITS)) &
979                             YAFFS_TNODES_INTERNAL_MASK;
980
981                         if ((l > 1) && !tn->internal[x]) {
982                                 /* Add missing non-level-zero tnode */
983                                 tn->internal[x] = yaffs_get_tnode(dev);
984                                 if (!tn->internal[x])
985                                         return NULL;
986                         } else if (l == 1) {
987                                 /* Looking from level 1 at level 0 */
988                                 if (passed_tn) {
989                                         /* If we already have one, release it */
990                                         if (tn->internal[x])
991                                                 yaffs_free_tnode(dev,
992                                                         tn->internal[x]);
993                                         tn->internal[x] = passed_tn;
994
995                                 } else if (!tn->internal[x]) {
996                                         /* Don't have one, none passed in */
997                                         tn->internal[x] = yaffs_get_tnode(dev);
998                                         if (!tn->internal[x])
999                                                 return NULL;
1000                                 }
1001                         }
1002
1003                         tn = tn->internal[x];
1004                         l--;
1005                 }
1006         } else {
1007                 /* top is level 0 */
1008                 if (passed_tn) {
1009                         memcpy(tn, passed_tn,
1010                                (dev->tnode_width * YAFFS_NTNODES_LEVEL0) / 8);
1011                         yaffs_free_tnode(dev, passed_tn);
1012                 }
1013         }
1014
1015         return tn;
1016 }
1017
1018 static int yaffs_tags_match(const struct yaffs_ext_tags *tags, int obj_id,
1019                             int chunk_obj)
1020 {
1021         return (tags->chunk_id == chunk_obj &&
1022                 tags->obj_id == obj_id &&
1023                 !tags->is_deleted) ? 1 : 0;
1024
1025 }
1026
1027 static int yaffs_find_chunk_in_group(struct yaffs_dev *dev, int the_chunk,
1028                                         struct yaffs_ext_tags *tags, int obj_id,
1029                                         int inode_chunk)
1030 {
1031         int j;
1032
1033         for (j = 0; the_chunk && j < dev->chunk_grp_size; j++) {
1034                 if (yaffs_check_chunk_bit
1035                     (dev, the_chunk / dev->param.chunks_per_block,
1036                      the_chunk % dev->param.chunks_per_block)) {
1037
1038                         if (dev->chunk_grp_size == 1)
1039                                 return the_chunk;
1040                         else {
1041                                 yaffs_rd_chunk_tags_nand(dev, the_chunk, NULL,
1042                                                          tags);
1043                                 if (yaffs_tags_match(tags,
1044                                                         obj_id, inode_chunk)) {
1045                                         /* found it; */
1046                                         return the_chunk;
1047                                 }
1048                         }
1049                 }
1050                 the_chunk++;
1051         }
1052         return -1;
1053 }
1054
1055 int yaffs_find_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
1056                                     struct yaffs_ext_tags *tags)
1057 {
1058         /*Get the Tnode, then get the level 0 offset chunk offset */
1059         struct yaffs_tnode *tn;
1060         int the_chunk = -1;
1061         struct yaffs_ext_tags local_tags;
1062         int ret_val = -1;
1063         struct yaffs_dev *dev = in->my_dev;
1064
1065         if (!tags) {
1066                 /* Passed a NULL, so use our own tags space */
1067                 tags = &local_tags;
1068         }
1069
1070         tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
1071
1072         if (!tn)
1073                 return ret_val;
1074
1075         the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);
1076
1077         ret_val = yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
1078                                               inode_chunk);
1079         return ret_val;
1080 }
1081
1082 static int yaffs_find_del_file_chunk(struct yaffs_obj *in, int inode_chunk,
1083                                      struct yaffs_ext_tags *tags)
1084 {
1085         /* Get the Tnode, then get the level 0 offset chunk offset */
1086         struct yaffs_tnode *tn;
1087         int the_chunk = -1;
1088         struct yaffs_ext_tags local_tags;
1089         struct yaffs_dev *dev = in->my_dev;
1090         int ret_val = -1;
1091
1092         if (!tags) {
1093                 /* Passed a NULL, so use our own tags space */
1094                 tags = &local_tags;
1095         }
1096
1097         tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
1098
1099         if (!tn)
1100                 return ret_val;
1101
1102         the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);
1103
1104         ret_val = yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
1105                                               inode_chunk);
1106
1107         /* Delete the entry in the filestructure (if found) */
1108         if (ret_val != -1)
1109                 yaffs_load_tnode_0(dev, tn, inode_chunk, 0);
1110
1111         return ret_val;
1112 }
1113
1114 int yaffs_put_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
1115                             int nand_chunk, int in_scan)
1116 {
1117         /* NB in_scan is zero unless scanning.
1118          * For forward scanning, in_scan is > 0;
1119          * for backward scanning in_scan is < 0
1120          *
1121          * nand_chunk = 0 is a dummy insert to make sure the tnodes are there.
1122          */
1123
1124         struct yaffs_tnode *tn;
1125         struct yaffs_dev *dev = in->my_dev;
1126         int existing_cunk;
1127         struct yaffs_ext_tags existing_tags;
1128         struct yaffs_ext_tags new_tags;
1129         unsigned existing_serial, new_serial;
1130
1131         if (in->variant_type != YAFFS_OBJECT_TYPE_FILE) {
1132                 /* Just ignore an attempt at putting a chunk into a non-file
1133                  * during scanning.
1134                  * If it is not during Scanning then something went wrong!
1135                  */
1136                 if (!in_scan) {
1137                         yaffs_trace(YAFFS_TRACE_ERROR,
1138                                 "yaffs tragedy:attempt to put data chunk into a non-file"
1139                                 );
1140                         BUG();
1141                 }
1142
1143                 yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
1144                 return YAFFS_OK;
1145         }
1146
1147         tn = yaffs_add_find_tnode_0(dev,
1148                                     &in->variant.file_variant,
1149                                     inode_chunk, NULL);
1150         if (!tn)
1151                 return YAFFS_FAIL;
1152
1153         if (!nand_chunk)
1154                 /* Dummy insert, bail now */
1155                 return YAFFS_OK;
1156
1157         existing_cunk = yaffs_get_group_base(dev, tn, inode_chunk);
1158
1159         if (in_scan != 0) {
1160                 /* If we're scanning then we need to test for duplicates
1161                  * NB This does not need to be efficient since it should only
1162                  * happen when the power fails during a write, then only one
1163                  * chunk should ever be affected.
1164                  *
1165                  * Correction for YAFFS2: This could happen quite a lot and we
1166                  * need to think about efficiency! TODO
1167                  * Update: For backward scanning we don't need to re-read tags
1168                  * so this is quite cheap.
1169                  */
1170
1171                 if (existing_cunk > 0) {
1172                         /* NB Right now existing chunk will not be real
1173                          * chunk_id if the chunk group size > 1
1174                          * thus we have to do a FindChunkInFile to get the
1175                          * real chunk id.
1176                          *
1177                          * We have a duplicate now we need to decide which
1178                          * one to use:
1179                          *
1180                          * Backwards scanning YAFFS2: The old one is what
1181                          * we use, dump the new one.
1182                          * YAFFS1: Get both sets of tags and compare serial
1183                          * numbers.
1184                          */
1185
1186                         if (in_scan > 0) {
1187                                 /* Only do this for forward scanning */
1188                                 yaffs_rd_chunk_tags_nand(dev,
1189                                                          nand_chunk,
1190                                                          NULL, &new_tags);
1191
1192                                 /* Do a proper find */
1193                                 existing_cunk =
1194                                     yaffs_find_chunk_in_file(in, inode_chunk,
1195                                                              &existing_tags);
1196                         }
1197
1198                         if (existing_cunk <= 0) {
1199                                 /*Hoosterman - how did this happen? */
1200
1201                                 yaffs_trace(YAFFS_TRACE_ERROR,
1202                                         "yaffs tragedy: existing chunk < 0 in scan"
1203                                         );
1204
1205                         }
1206
1207                         /* NB The deleted flags should be false, otherwise
1208                          * the chunks will not be loaded during a scan
1209                          */
1210
1211                         if (in_scan > 0) {
1212                                 new_serial = new_tags.serial_number;
1213                                 existing_serial = existing_tags.serial_number;
1214                         }
1215
1216                         if ((in_scan > 0) &&
1217                             (existing_cunk <= 0 ||
1218                              ((existing_serial + 1) & 3) == new_serial)) {
1219                                 /* Forward scanning.
1220                                  * Use new
1221                                  * Delete the old one and drop through to
1222                                  * update the tnode
1223                                  */
1224                                 yaffs_chunk_del(dev, existing_cunk, 1,
1225                                                 __LINE__);
1226                         } else {
1227                                 /* Backward scanning or we want to use the
1228                                  * existing one
1229                                  * Delete the new one and return early so that
1230                                  * the tnode isn't changed
1231                                  */
1232                                 yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
1233                                 return YAFFS_OK;
1234                         }
1235                 }
1236
1237         }
1238
1239         if (existing_cunk == 0)
1240                 in->n_data_chunks++;
1241
1242         yaffs_load_tnode_0(dev, tn, inode_chunk, nand_chunk);
1243
1244         return YAFFS_OK;
1245 }
1246
1247 static void yaffs_soft_del_chunk(struct yaffs_dev *dev, int chunk)
1248 {
1249         struct yaffs_block_info *the_block;
1250         unsigned block_no;
1251
1252         yaffs_trace(YAFFS_TRACE_DELETION, "soft delete chunk %d", chunk);
1253
1254         block_no = chunk / dev->param.chunks_per_block;
1255         the_block = yaffs_get_block_info(dev, block_no);
1256         if (the_block) {
1257                 the_block->soft_del_pages++;
1258                 dev->n_free_chunks++;
1259                 yaffs2_update_oldest_dirty_seq(dev, block_no, the_block);
1260         }
1261 }
1262
1263 /* SoftDeleteWorker scans backwards through the tnode tree and soft deletes all
1264  * the chunks in the file.
1265  * All soft deleting does is increment the block's softdelete count and pulls
1266  * the chunk out of the tnode.
1267  * Thus, essentially this is the same as DeleteWorker except that the chunks
1268  * are soft deleted.
1269  */
1270
1271 static int yaffs_soft_del_worker(struct yaffs_obj *in, struct yaffs_tnode *tn,
1272                                  u32 level, int chunk_offset)
1273 {
1274         int i;
1275         int the_chunk;
1276         int all_done = 1;
1277         struct yaffs_dev *dev = in->my_dev;
1278
1279         if (!tn)
1280                 return 1;
1281
1282         if (level > 0) {
1283                 for (i = YAFFS_NTNODES_INTERNAL - 1;
1284                         all_done && i >= 0;
1285                         i--) {
1286                         if (tn->internal[i]) {
1287                                 all_done =
1288                                     yaffs_soft_del_worker(in,
1289                                         tn->internal[i],
1290                                         level - 1,
1291                                         (chunk_offset <<
1292                                         YAFFS_TNODES_INTERNAL_BITS)
1293                                         + i);
1294                                 if (all_done) {
1295                                         yaffs_free_tnode(dev,
1296                                                 tn->internal[i]);
1297                                         tn->internal[i] = NULL;
1298                                 } else {
1299                                         /* Can this happen? */
1300                                 }
1301                         }
1302                 }
1303                 return (all_done) ? 1 : 0;
1304         }
1305
1306         /* level 0 */
1307          for (i = YAFFS_NTNODES_LEVEL0 - 1; i >= 0; i--) {
1308                 the_chunk = yaffs_get_group_base(dev, tn, i);
1309                 if (the_chunk) {
1310                         yaffs_soft_del_chunk(dev, the_chunk);
1311                         yaffs_load_tnode_0(dev, tn, i, 0);
1312                 }
1313         }
1314         return 1;
1315 }
1316
1317 static void yaffs_remove_obj_from_dir(struct yaffs_obj *obj)
1318 {
1319         struct yaffs_dev *dev = obj->my_dev;
1320         struct yaffs_obj *parent;
1321
1322         yaffs_verify_obj_in_dir(obj);
1323         parent = obj->parent;
1324
1325         yaffs_verify_dir(parent);
1326
1327         if (dev && dev->param.remove_obj_fn)
1328                 dev->param.remove_obj_fn(obj);
1329
1330         list_del_init(&obj->siblings);
1331         obj->parent = NULL;
1332
1333         yaffs_verify_dir(parent);
1334 }
1335
1336 void yaffs_add_obj_to_dir(struct yaffs_obj *directory, struct yaffs_obj *obj)
1337 {
1338         if (!directory) {
1339                 yaffs_trace(YAFFS_TRACE_ALWAYS,
1340                         "tragedy: Trying to add an object to a null pointer directory"
1341                         );
1342                 BUG();
1343                 return;
1344         }
1345         if (directory->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
1346                 yaffs_trace(YAFFS_TRACE_ALWAYS,
1347                         "tragedy: Trying to add an object to a non-directory"
1348                         );
1349                 BUG();
1350         }
1351
1352         if (obj->siblings.prev == NULL) {
1353                 /* Not initialised */
1354                 BUG();
1355         }
1356
1357         yaffs_verify_dir(directory);
1358
1359         yaffs_remove_obj_from_dir(obj);
1360
1361         /* Now add it */
1362         list_add(&obj->siblings, &directory->variant.dir_variant.children);
1363         obj->parent = directory;
1364
1365         if (directory == obj->my_dev->unlinked_dir
1366             || directory == obj->my_dev->del_dir) {
1367                 obj->unlinked = 1;
1368                 obj->my_dev->n_unlinked_files++;
1369                 obj->rename_allowed = 0;
1370         }
1371
1372         yaffs_verify_dir(directory);
1373         yaffs_verify_obj_in_dir(obj);
1374 }
1375
1376 static int yaffs_change_obj_name(struct yaffs_obj *obj,
1377                                  struct yaffs_obj *new_dir,
1378                                  const YCHAR *new_name, int force, int shadows)
1379 {
1380         int unlink_op;
1381         int del_op;
1382         struct yaffs_obj *existing_target;
1383
1384         if (new_dir == NULL)
1385                 new_dir = obj->parent;  /* use the old directory */
1386
1387         if (new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
1388                 yaffs_trace(YAFFS_TRACE_ALWAYS,
1389                         "tragedy: yaffs_change_obj_name: new_dir is not a directory"
1390                         );
1391                 BUG();
1392         }
1393
1394         unlink_op = (new_dir == obj->my_dev->unlinked_dir);
1395         del_op = (new_dir == obj->my_dev->del_dir);
1396
1397         existing_target = yaffs_find_by_name(new_dir, new_name);
1398
1399         /* If the object is a file going into the unlinked directory,
1400          *   then it is OK to just stuff it in since duplicate names are OK.
1401          *   else only proceed if the new name does not exist and we're putting
1402          *   it into a directory.
1403          */
1404         if (!(unlink_op || del_op || force ||
1405               shadows > 0 || !existing_target) ||
1406               new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
1407                 return YAFFS_FAIL;
1408
1409         yaffs_set_obj_name(obj, new_name);
1410         obj->dirty = 1;
1411         yaffs_add_obj_to_dir(new_dir, obj);
1412
1413         if (unlink_op)
1414                 obj->unlinked = 1;
1415
1416         /* If it is a deletion then we mark it as a shrink for gc  */
1417         if (yaffs_update_oh(obj, new_name, 0, del_op, shadows, NULL) >= 0)
1418                 return YAFFS_OK;
1419
1420         return YAFFS_FAIL;
1421 }
1422
1423 /*------------------------ Short Operations Cache ------------------------------
1424  *   In many situations where there is no high level buffering  a lot of
1425  *   reads might be short sequential reads, and a lot of writes may be short
1426  *   sequential writes. eg. scanning/writing a jpeg file.
1427  *   In these cases, a short read/write cache can provide a huge perfomance
1428  *   benefit with dumb-as-a-rock code.
1429  *   In Linux, the page cache provides read buffering and the short op cache
1430  *   provides write buffering.
1431  *
1432  *   There are a small number (~10) of cache chunks per device so that we don't
1433  *   need a very intelligent search.
1434  */
1435
1436 static int yaffs_obj_cache_dirty(struct yaffs_obj *obj)
1437 {
1438         struct yaffs_dev *dev = obj->my_dev;
1439         int i;
1440         struct yaffs_cache *cache;
1441         int n_caches = obj->my_dev->param.n_caches;
1442
1443         for (i = 0; i < n_caches; i++) {
1444                 cache = &dev->cache[i];
1445                 if (cache->object == obj && cache->dirty)
1446                         return 1;
1447         }
1448
1449         return 0;
1450 }
1451
1452 static void yaffs_flush_single_cache(struct yaffs_cache *cache, int discard)
1453 {
1454
1455         if (!cache || cache->locked)
1456                 return;
1457
1458         /* Write it out and free it up  if need be.*/
1459         if (cache->dirty) {
1460                 yaffs_wr_data_obj(cache->object,
1461                                   cache->chunk_id,
1462                                   cache->data,
1463                                   cache->n_bytes,
1464                                   1);
1465
1466                 cache->dirty = 0;
1467         }
1468
1469         if (discard)
1470                 cache->object = NULL;
1471 }
1472
1473 static void yaffs_flush_file_cache(struct yaffs_obj *obj, int discard)
1474 {
1475         struct yaffs_dev *dev = obj->my_dev;
1476         int i;
1477         struct yaffs_cache *cache;
1478         int n_caches = obj->my_dev->param.n_caches;
1479
1480         if (n_caches < 1)
1481                 return;
1482
1483
1484         /* Find the chunks for this object and flush them. */
1485         for (i = 0; i < n_caches; i++) {
1486                 cache = &dev->cache[i];
1487                 if (cache->object == obj)
1488                         yaffs_flush_single_cache(cache, discard);
1489         }
1490
1491 }
1492
1493
1494 void yaffs_flush_whole_cache(struct yaffs_dev *dev, int discard)
1495 {
1496         struct yaffs_obj *obj;
1497         int n_caches = dev->param.n_caches;
1498         int i;
1499
1500         /* Find a dirty object in the cache and flush it...
1501          * until there are no further dirty objects.
1502          */
1503         do {
1504                 obj = NULL;
1505                 for (i = 0; i < n_caches && !obj; i++) {
1506                         if (dev->cache[i].object && dev->cache[i].dirty)
1507                                 obj = dev->cache[i].object;
1508                 }
1509                 if (obj)
1510                         yaffs_flush_file_cache(obj, discard);
1511         } while (obj);
1512
1513 }
1514
1515 /* Grab us an unused cache chunk for use.
1516  * First look for an empty one.
1517  * Then look for the least recently used non-dirty one.
1518  * Then look for the least recently used dirty one...., flush and look again.
1519  */
1520 static struct yaffs_cache *yaffs_grab_chunk_worker(struct yaffs_dev *dev)
1521 {
1522         int i;
1523
1524         if (dev->param.n_caches > 0) {
1525                 for (i = 0; i < dev->param.n_caches; i++) {
1526                         if (!dev->cache[i].object)
1527                                 return &dev->cache[i];
1528                 }
1529         }
1530
1531         return NULL;
1532 }
1533
1534 static struct yaffs_cache *yaffs_grab_chunk_cache(struct yaffs_dev *dev)
1535 {
1536         struct yaffs_cache *cache;
1537         int usage;
1538         int i;
1539
1540         if (dev->param.n_caches < 1)
1541                 return NULL;
1542
1543         /* First look for an unused cache */
1544
1545         cache = yaffs_grab_chunk_worker(dev);
1546
1547         if (cache)
1548                 return cache;
1549
1550         /*
1551          * Thery were all in use.
1552          * Find the LRU cache and flush it if it is dirty.
1553          */
1554
1555         usage = -1;
1556         cache = NULL;
1557
1558         for (i = 0; i < dev->param.n_caches; i++) {
1559                 if (dev->cache[i].object &&
1560                     !dev->cache[i].locked &&
1561                     (dev->cache[i].last_use < usage || !cache)) {
1562                                 usage = dev->cache[i].last_use;
1563                                 cache = &dev->cache[i];
1564                 }
1565         }
1566
1567 #if 1
1568         yaffs_flush_single_cache(cache, 1);
1569 #else
1570         yaffs_flush_file_cache(cache->object, 1);
1571         cache = yaffs_grab_chunk_worker(dev);
1572 #endif
1573
1574         return cache;
1575 }
1576
1577 /* Find a cached chunk */
1578 static struct yaffs_cache *yaffs_find_chunk_cache(const struct yaffs_obj *obj,
1579                                                   int chunk_id)
1580 {
1581         struct yaffs_dev *dev = obj->my_dev;
1582         int i;
1583
1584         if (dev->param.n_caches < 1)
1585                 return NULL;
1586
1587         for (i = 0; i < dev->param.n_caches; i++) {
1588                 if (dev->cache[i].object == obj &&
1589                     dev->cache[i].chunk_id == chunk_id) {
1590                         dev->cache_hits++;
1591
1592                         return &dev->cache[i];
1593                 }
1594         }
1595         return NULL;
1596 }
1597
1598 /* Mark the chunk for the least recently used algorithym */
1599 static void yaffs_use_cache(struct yaffs_dev *dev, struct yaffs_cache *cache,
1600                             int is_write)
1601 {
1602         int i;
1603
1604         if (dev->param.n_caches < 1)
1605                 return;
1606
1607         if (dev->cache_last_use < 0 ||
1608                 dev->cache_last_use > 100000000) {
1609                 /* Reset the cache usages */
1610                 for (i = 1; i < dev->param.n_caches; i++)
1611                         dev->cache[i].last_use = 0;
1612
1613                 dev->cache_last_use = 0;
1614         }
1615         dev->cache_last_use++;
1616         cache->last_use = dev->cache_last_use;
1617
1618         if (is_write)
1619                 cache->dirty = 1;
1620 }
1621
1622 /* Invalidate a single cache page.
1623  * Do this when a whole page gets written,
1624  * ie the short cache for this page is no longer valid.
1625  */
1626 static void yaffs_invalidate_chunk_cache(struct yaffs_obj *object, int chunk_id)
1627 {
1628         struct yaffs_cache *cache;
1629
1630         if (object->my_dev->param.n_caches > 0) {
1631                 cache = yaffs_find_chunk_cache(object, chunk_id);
1632
1633                 if (cache)
1634                         cache->object = NULL;
1635         }
1636 }
1637
1638 /* Invalidate all the cache pages associated with this object
1639  * Do this whenever ther file is deleted or resized.
1640  */
1641 static void yaffs_invalidate_whole_cache(struct yaffs_obj *in)
1642 {
1643         int i;
1644         struct yaffs_dev *dev = in->my_dev;
1645
1646         if (dev->param.n_caches > 0) {
1647                 /* Invalidate it. */
1648                 for (i = 0; i < dev->param.n_caches; i++) {
1649                         if (dev->cache[i].object == in)
1650                                 dev->cache[i].object = NULL;
1651                 }
1652         }
1653 }
1654
1655 static void yaffs_unhash_obj(struct yaffs_obj *obj)
1656 {
1657         int bucket;
1658         struct yaffs_dev *dev = obj->my_dev;
1659
1660         /* If it is still linked into the bucket list, free from the list */
1661         if (!list_empty(&obj->hash_link)) {
1662                 list_del_init(&obj->hash_link);
1663                 bucket = yaffs_hash_fn(obj->obj_id);
1664                 dev->obj_bucket[bucket].count--;
1665         }
1666 }
1667
1668 /*  FreeObject frees up a Object and puts it back on the free list */
1669 static void yaffs_free_obj(struct yaffs_obj *obj)
1670 {
1671         struct yaffs_dev *dev;
1672
1673         if (!obj) {
1674                 BUG();
1675                 return;
1676         }
1677         dev = obj->my_dev;
1678         yaffs_trace(YAFFS_TRACE_OS, "FreeObject %p inode %p",
1679                 obj, obj->my_inode);
1680         if (obj->parent)
1681                 BUG();
1682         if (!list_empty(&obj->siblings))
1683                 BUG();
1684
1685         if (obj->my_inode) {
1686                 /* We're still hooked up to a cached inode.
1687                  * Don't delete now, but mark for later deletion
1688                  */
1689                 obj->defered_free = 1;
1690                 return;
1691         }
1692
1693         yaffs_unhash_obj(obj);
1694
1695         yaffs_free_raw_obj(dev, obj);
1696         dev->n_obj--;
1697         dev->checkpoint_blocks_required = 0;    /* force recalculation */
1698 }
1699
1700 void yaffs_handle_defered_free(struct yaffs_obj *obj)
1701 {
1702         if (obj->defered_free)
1703                 yaffs_free_obj(obj);
1704 }
1705
1706 static int yaffs_generic_obj_del(struct yaffs_obj *in)
1707 {
1708         /* Iinvalidate the file's data in the cache, without flushing. */
1709         yaffs_invalidate_whole_cache(in);
1710
1711         if (in->my_dev->param.is_yaffs2 && in->parent != in->my_dev->del_dir) {
1712                 /* Move to unlinked directory so we have a deletion record */
1713                 yaffs_change_obj_name(in, in->my_dev->del_dir, _Y("deleted"), 0,
1714                                       0);
1715         }
1716
1717         yaffs_remove_obj_from_dir(in);
1718         yaffs_chunk_del(in->my_dev, in->hdr_chunk, 1, __LINE__);
1719         in->hdr_chunk = 0;
1720
1721         yaffs_free_obj(in);
1722         return YAFFS_OK;
1723
1724 }
1725
1726 static void yaffs_soft_del_file(struct yaffs_obj *obj)
1727 {
1728         if (!obj->deleted ||
1729             obj->variant_type != YAFFS_OBJECT_TYPE_FILE ||
1730             obj->soft_del)
1731                 return;
1732
1733         if (obj->n_data_chunks <= 0) {
1734                 /* Empty file with no duplicate object headers,
1735                  * just delete it immediately */
1736                 yaffs_free_tnode(obj->my_dev, obj->variant.file_variant.top);
1737                 obj->variant.file_variant.top = NULL;
1738                 yaffs_trace(YAFFS_TRACE_TRACING,
1739                         "yaffs: Deleting empty file %d",
1740                         obj->obj_id);
1741                 yaffs_generic_obj_del(obj);
1742         } else {
1743                 yaffs_soft_del_worker(obj,
1744                                       obj->variant.file_variant.top,
1745                                       obj->variant.
1746                                       file_variant.top_level, 0);
1747                 obj->soft_del = 1;
1748         }
1749 }
1750
1751 /* Pruning removes any part of the file structure tree that is beyond the
1752  * bounds of the file (ie that does not point to chunks).
1753  *
1754  * A file should only get pruned when its size is reduced.
1755  *
1756  * Before pruning, the chunks must be pulled from the tree and the
1757  * level 0 tnode entries must be zeroed out.
1758  * Could also use this for file deletion, but that's probably better handled
1759  * by a special case.
1760  *
1761  * This function is recursive. For levels > 0 the function is called again on
1762  * any sub-tree. For level == 0 we just check if the sub-tree has data.
1763  * If there is no data in a subtree then it is pruned.
1764  */
1765
1766 static struct yaffs_tnode *yaffs_prune_worker(struct yaffs_dev *dev,
1767                                               struct yaffs_tnode *tn, u32 level,
1768                                               int del0)
1769 {
1770         int i;
1771         int has_data;
1772
1773         if (!tn)
1774                 return tn;
1775
1776         has_data = 0;
1777
1778         if (level > 0) {
1779                 for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++) {
1780                         if (tn->internal[i]) {
1781                                 tn->internal[i] =
1782                                     yaffs_prune_worker(dev,
1783                                                 tn->internal[i],
1784                                                 level - 1,
1785                                                 (i == 0) ? del0 : 1);
1786                         }
1787
1788                         if (tn->internal[i])
1789                                 has_data++;
1790                 }
1791         } else {
1792                 int tnode_size_u32 = dev->tnode_size / sizeof(u32);
1793                 u32 *map = (u32 *) tn;
1794
1795                 for (i = 0; !has_data && i < tnode_size_u32; i++) {
1796                         if (map[i])
1797                                 has_data++;
1798                 }
1799         }
1800
1801         if (has_data == 0 && del0) {
1802                 /* Free and return NULL */
1803                 yaffs_free_tnode(dev, tn);
1804                 tn = NULL;
1805         }
1806         return tn;
1807 }
1808
1809 static int yaffs_prune_tree(struct yaffs_dev *dev,
1810                             struct yaffs_file_var *file_struct)
1811 {
1812         int i;
1813         int has_data;
1814         int done = 0;
1815         struct yaffs_tnode *tn;
1816
1817         if (file_struct->top_level < 1)
1818                 return YAFFS_OK;
1819
1820         file_struct->top =
1821            yaffs_prune_worker(dev, file_struct->top, file_struct->top_level, 0);
1822
1823         /* Now we have a tree with all the non-zero branches NULL but
1824          * the height is the same as it was.
1825          * Let's see if we can trim internal tnodes to shorten the tree.
1826          * We can do this if only the 0th element in the tnode is in use
1827          * (ie all the non-zero are NULL)
1828          */
1829
1830         while (file_struct->top_level && !done) {
1831                 tn = file_struct->top;
1832
1833                 has_data = 0;
1834                 for (i = 1; i < YAFFS_NTNODES_INTERNAL; i++) {
1835                         if (tn->internal[i])
1836                                 has_data++;
1837                 }
1838
1839                 if (!has_data) {
1840                         file_struct->top = tn->internal[0];
1841                         file_struct->top_level--;
1842                         yaffs_free_tnode(dev, tn);
1843                 } else {
1844                         done = 1;
1845                 }
1846         }
1847
1848         return YAFFS_OK;
1849 }
1850
1851 /*-------------------- End of File Structure functions.-------------------*/
1852
1853 /* alloc_empty_obj gets us a clean Object.*/
1854 static struct yaffs_obj *yaffs_alloc_empty_obj(struct yaffs_dev *dev)
1855 {
1856         struct yaffs_obj *obj = yaffs_alloc_raw_obj(dev);
1857
1858         if (!obj)
1859                 return obj;
1860
1861         dev->n_obj++;
1862
1863         /* Now sweeten it up... */
1864
1865         memset(obj, 0, sizeof(struct yaffs_obj));
1866         obj->being_created = 1;
1867
1868         obj->my_dev = dev;
1869         obj->hdr_chunk = 0;
1870         obj->variant_type = YAFFS_OBJECT_TYPE_UNKNOWN;
1871         INIT_LIST_HEAD(&(obj->hard_links));
1872         INIT_LIST_HEAD(&(obj->hash_link));
1873         INIT_LIST_HEAD(&obj->siblings);
1874
1875         /* Now make the directory sane */
1876         if (dev->root_dir) {
1877                 obj->parent = dev->root_dir;
1878                 list_add(&(obj->siblings),
1879                          &dev->root_dir->variant.dir_variant.children);
1880         }
1881
1882         /* Add it to the lost and found directory.
1883          * NB Can't put root or lost-n-found in lost-n-found so
1884          * check if lost-n-found exists first
1885          */
1886         if (dev->lost_n_found)
1887                 yaffs_add_obj_to_dir(dev->lost_n_found, obj);
1888
1889         obj->being_created = 0;
1890
1891         dev->checkpoint_blocks_required = 0;    /* force recalculation */
1892
1893         return obj;
1894 }
1895
1896 static int yaffs_find_nice_bucket(struct yaffs_dev *dev)
1897 {
1898         int i;
1899         int l = 999;
1900         int lowest = 999999;
1901
1902         /* Search for the shortest list or one that
1903          * isn't too long.
1904          */
1905
1906         for (i = 0; i < 10 && lowest > 4; i++) {
1907                 dev->bucket_finder++;
1908                 dev->bucket_finder %= YAFFS_NOBJECT_BUCKETS;
1909                 if (dev->obj_bucket[dev->bucket_finder].count < lowest) {
1910                         lowest = dev->obj_bucket[dev->bucket_finder].count;
1911                         l = dev->bucket_finder;
1912                 }
1913         }
1914
1915         return l;
1916 }
1917
1918 static int yaffs_new_obj_id(struct yaffs_dev *dev)
1919 {
1920         int bucket = yaffs_find_nice_bucket(dev);
1921         int found = 0;
1922         struct list_head *i;
1923         u32 n = (u32) bucket;
1924
1925         /*
1926          * Now find an object value that has not already been taken
1927          * by scanning the list, incrementing each time by number of buckets.
1928          */
1929         while (!found) {
1930                 found = 1;
1931                 n += YAFFS_NOBJECT_BUCKETS;
1932                 list_for_each(i, &dev->obj_bucket[bucket].list) {
1933                         /* Check if this value is already taken. */
1934                         if (i && list_entry(i, struct yaffs_obj,
1935                                             hash_link)->obj_id == n)
1936                                 found = 0;
1937                 }
1938         }
1939         return n;
1940 }
1941
1942 static void yaffs_hash_obj(struct yaffs_obj *in)
1943 {
1944         int bucket = yaffs_hash_fn(in->obj_id);
1945         struct yaffs_dev *dev = in->my_dev;
1946
1947         list_add(&in->hash_link, &dev->obj_bucket[bucket].list);
1948         dev->obj_bucket[bucket].count++;
1949 }
1950
1951 struct yaffs_obj *yaffs_find_by_number(struct yaffs_dev *dev, u32 number)
1952 {
1953         int bucket = yaffs_hash_fn(number);
1954         struct list_head *i;
1955         struct yaffs_obj *in;
1956
1957         list_for_each(i, &dev->obj_bucket[bucket].list) {
1958                 /* Look if it is in the list */
1959                 in = list_entry(i, struct yaffs_obj, hash_link);
1960                 if (in->obj_id == number) {
1961                         /* Don't show if it is defered free */
1962                         if (in->defered_free)
1963                                 return NULL;
1964                         return in;
1965                 }
1966         }
1967
1968         return NULL;
1969 }
1970
1971 static struct yaffs_obj *yaffs_new_obj(struct yaffs_dev *dev, int number,
1972                                 enum yaffs_obj_type type)
1973 {
1974         struct yaffs_obj *the_obj = NULL;
1975         struct yaffs_tnode *tn = NULL;
1976
1977         if (number < 0)
1978                 number = yaffs_new_obj_id(dev);
1979
1980         if (type == YAFFS_OBJECT_TYPE_FILE) {
1981                 tn = yaffs_get_tnode(dev);
1982                 if (!tn)
1983                         return NULL;
1984         }
1985
1986         the_obj = yaffs_alloc_empty_obj(dev);
1987         if (!the_obj) {
1988                 if (tn)
1989                         yaffs_free_tnode(dev, tn);
1990                 return NULL;
1991         }
1992
1993         the_obj->fake = 0;
1994         the_obj->rename_allowed = 1;
1995         the_obj->unlink_allowed = 1;
1996         the_obj->obj_id = number;
1997         yaffs_hash_obj(the_obj);
1998         the_obj->variant_type = type;
1999         yaffs_load_current_time(the_obj, 1, 1);
2000
2001         switch (type) {
2002         case YAFFS_OBJECT_TYPE_FILE:
2003                 the_obj->variant.file_variant.file_size = 0;
2004                 the_obj->variant.file_variant.scanned_size = 0;
2005                 the_obj->variant.file_variant.shrink_size =
2006                                                 yaffs_max_file_size(dev);
2007                 the_obj->variant.file_variant.top_level = 0;
2008                 the_obj->variant.file_variant.top = tn;
2009                 break;
2010         case YAFFS_OBJECT_TYPE_DIRECTORY:
2011                 INIT_LIST_HEAD(&the_obj->variant.dir_variant.children);
2012                 INIT_LIST_HEAD(&the_obj->variant.dir_variant.dirty);
2013                 break;
2014         case YAFFS_OBJECT_TYPE_SYMLINK:
2015         case YAFFS_OBJECT_TYPE_HARDLINK:
2016         case YAFFS_OBJECT_TYPE_SPECIAL:
2017                 /* No action required */
2018                 break;
2019         case YAFFS_OBJECT_TYPE_UNKNOWN:
2020                 /* todo this should not happen */
2021                 break;
2022         }
2023         return the_obj;
2024 }
2025
2026 static struct yaffs_obj *yaffs_create_fake_dir(struct yaffs_dev *dev,
2027                                                int number, u32 mode)
2028 {
2029
2030         struct yaffs_obj *obj =
2031             yaffs_new_obj(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
2032
2033         if (!obj)
2034                 return NULL;
2035
2036         obj->fake = 1;  /* it is fake so it might not use NAND */
2037         obj->rename_allowed = 0;
2038         obj->unlink_allowed = 0;
2039         obj->deleted = 0;
2040         obj->unlinked = 0;
2041         obj->yst_mode = mode;
2042         obj->my_dev = dev;
2043         obj->hdr_chunk = 0;     /* Not a valid chunk. */
2044         return obj;
2045
2046 }
2047
2048
2049 static void yaffs_init_tnodes_and_objs(struct yaffs_dev *dev)
2050 {
2051         int i;
2052
2053         dev->n_obj = 0;
2054         dev->n_tnodes = 0;
2055         yaffs_init_raw_tnodes_and_objs(dev);
2056
2057         for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
2058                 INIT_LIST_HEAD(&dev->obj_bucket[i].list);
2059                 dev->obj_bucket[i].count = 0;
2060         }
2061 }
2062
2063 struct yaffs_obj *yaffs_find_or_create_by_number(struct yaffs_dev *dev,
2064                                                  int number,
2065                                                  enum yaffs_obj_type type)
2066 {
2067         struct yaffs_obj *the_obj = NULL;
2068
2069         if (number > 0)
2070                 the_obj = yaffs_find_by_number(dev, number);
2071
2072         if (!the_obj)
2073                 the_obj = yaffs_new_obj(dev, number, type);
2074
2075         return the_obj;
2076
2077 }
2078
2079 YCHAR *yaffs_clone_str(const YCHAR *str)
2080 {
2081         YCHAR *new_str = NULL;
2082         int len;
2083
2084         if (!str)
2085                 str = _Y("");
2086
2087         len = strnlen(str, YAFFS_MAX_ALIAS_LENGTH);
2088         new_str = kmalloc((len + 1) * sizeof(YCHAR), GFP_NOFS);
2089         if (new_str) {
2090                 strncpy(new_str, str, len);
2091                 new_str[len] = 0;
2092         }
2093         return new_str;
2094
2095 }
2096 /*
2097  *yaffs_update_parent() handles fixing a directories mtime and ctime when a new
2098  * link (ie. name) is created or deleted in the directory.
2099  *
2100  * ie.
2101  *   create dir/a : update dir's mtime/ctime
2102  *   rm dir/a:   update dir's mtime/ctime
2103  *   modify dir/a: don't update dir's mtimme/ctime
2104  *
2105  * This can be handled immediately or defered. Defering helps reduce the number
2106  * of updates when many files in a directory are changed within a brief period.
2107  *
2108  * If the directory updating is defered then yaffs_update_dirty_dirs must be
2109  * called periodically.
2110  */
2111
2112 static void yaffs_update_parent(struct yaffs_obj *obj)
2113 {
2114         struct yaffs_dev *dev;
2115
2116         if (!obj)
2117                 return;
2118         dev = obj->my_dev;
2119         obj->dirty = 1;
2120         yaffs_load_current_time(obj, 0, 1);
2121         if (dev->param.defered_dir_update) {
2122                 struct list_head *link = &obj->variant.dir_variant.dirty;
2123
2124                 if (list_empty(link)) {
2125                         list_add(link, &dev->dirty_dirs);
2126                         yaffs_trace(YAFFS_TRACE_BACKGROUND,
2127                           "Added object %d to dirty directories",
2128                            obj->obj_id);
2129                 }
2130
2131         } else {
2132                 yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
2133         }
2134 }
2135
2136 void yaffs_update_dirty_dirs(struct yaffs_dev *dev)
2137 {
2138         struct list_head *link;
2139         struct yaffs_obj *obj;
2140         struct yaffs_dir_var *d_s;
2141         union yaffs_obj_var *o_v;
2142
2143         yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update dirty directories");
2144
2145         while (!list_empty(&dev->dirty_dirs)) {
2146                 link = dev->dirty_dirs.next;
2147                 list_del_init(link);
2148
2149                 d_s = list_entry(link, struct yaffs_dir_var, dirty);
2150                 o_v = list_entry(d_s, union yaffs_obj_var, dir_variant);
2151                 obj = list_entry(o_v, struct yaffs_obj, variant);
2152
2153                 yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update directory %d",
2154                         obj->obj_id);
2155
2156                 if (obj->dirty)
2157                         yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
2158         }
2159 }
2160
2161 /*
2162  * Mknod (create) a new object.
2163  * equiv_obj only has meaning for a hard link;
2164  * alias_str only has meaning for a symlink.
2165  * rdev only has meaning for devices (a subset of special objects)
2166  */
2167
2168 static struct yaffs_obj *yaffs_create_obj(enum yaffs_obj_type type,
2169                                           struct yaffs_obj *parent,
2170                                           const YCHAR *name,
2171                                           u32 mode,
2172                                           u32 uid,
2173                                           u32 gid,
2174                                           struct yaffs_obj *equiv_obj,
2175                                           const YCHAR *alias_str, u32 rdev)
2176 {
2177         struct yaffs_obj *in;
2178         YCHAR *str = NULL;
2179         struct yaffs_dev *dev = parent->my_dev;
2180
2181         /* Check if the entry exists.
2182          * If it does then fail the call since we don't want a dup. */
2183         if (yaffs_find_by_name(parent, name))
2184                 return NULL;
2185
2186         if (type == YAFFS_OBJECT_TYPE_SYMLINK) {
2187                 str = yaffs_clone_str(alias_str);
2188                 if (!str)
2189                         return NULL;
2190         }
2191
2192         in = yaffs_new_obj(dev, -1, type);
2193
2194         if (!in) {
2195                 kfree(str);
2196                 return NULL;
2197         }
2198
2199         in->hdr_chunk = 0;
2200         in->valid = 1;
2201         in->variant_type = type;
2202
2203         in->yst_mode = mode;
2204
2205         yaffs_attribs_init(in, gid, uid, rdev);
2206
2207         in->n_data_chunks = 0;
2208
2209         yaffs_set_obj_name(in, name);
2210         in->dirty = 1;
2211
2212         yaffs_add_obj_to_dir(parent, in);
2213
2214         in->my_dev = parent->my_dev;
2215
2216         switch (type) {
2217         case YAFFS_OBJECT_TYPE_SYMLINK:
2218                 in->variant.symlink_variant.alias = str;
2219                 break;
2220         case YAFFS_OBJECT_TYPE_HARDLINK:
2221                 in->variant.hardlink_variant.equiv_obj = equiv_obj;
2222                 in->variant.hardlink_variant.equiv_id = equiv_obj->obj_id;
2223                 list_add(&in->hard_links, &equiv_obj->hard_links);
2224                 break;
2225         case YAFFS_OBJECT_TYPE_FILE:
2226         case YAFFS_OBJECT_TYPE_DIRECTORY:
2227         case YAFFS_OBJECT_TYPE_SPECIAL:
2228         case YAFFS_OBJECT_TYPE_UNKNOWN:
2229                 /* do nothing */
2230                 break;
2231         }
2232
2233         if (yaffs_update_oh(in, name, 0, 0, 0, NULL) < 0) {
2234                 /* Could not create the object header, fail */
2235                 yaffs_del_obj(in);
2236                 in = NULL;
2237         }
2238
2239         if (in)
2240                 yaffs_update_parent(parent);
2241
2242         return in;
2243 }
2244
2245 struct yaffs_obj *yaffs_create_file(struct yaffs_obj *parent,
2246                                     const YCHAR *name, u32 mode, u32 uid,
2247                                     u32 gid)
2248 {
2249         return yaffs_create_obj(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
2250                                 uid, gid, NULL, NULL, 0);
2251 }
2252
2253 struct yaffs_obj *yaffs_create_dir(struct yaffs_obj *parent, const YCHAR *name,
2254                                    u32 mode, u32 uid, u32 gid)
2255 {
2256         return yaffs_create_obj(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
2257                                 mode, uid, gid, NULL, NULL, 0);
2258 }
2259
2260 struct yaffs_obj *yaffs_create_special(struct yaffs_obj *parent,
2261                                        const YCHAR *name, u32 mode, u32 uid,
2262                                        u32 gid, u32 rdev)
2263 {
2264         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
2265                                 uid, gid, NULL, NULL, rdev);
2266 }
2267
2268 struct yaffs_obj *yaffs_create_symlink(struct yaffs_obj *parent,
2269                                        const YCHAR *name, u32 mode, u32 uid,
2270                                        u32 gid, const YCHAR *alias)
2271 {
2272         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
2273                                 uid, gid, NULL, alias, 0);
2274 }
2275
2276 /* yaffs_link_obj returns the object id of the equivalent object.*/
2277 struct yaffs_obj *yaffs_link_obj(struct yaffs_obj *parent, const YCHAR * name,
2278                                  struct yaffs_obj *equiv_obj)
2279 {
2280         /* Get the real object in case we were fed a hard link obj */
2281         equiv_obj = yaffs_get_equivalent_obj(equiv_obj);
2282
2283         if (yaffs_create_obj(YAFFS_OBJECT_TYPE_HARDLINK,
2284                         parent, name, 0, 0, 0,
2285                         equiv_obj, NULL, 0))
2286                 return equiv_obj;
2287
2288         return NULL;
2289
2290 }
2291
2292
2293
2294 /*---------------------- Block Management and Page Allocation -------------*/
2295
2296 static void yaffs_deinit_blocks(struct yaffs_dev *dev)
2297 {
2298         if (dev->block_info_alt && dev->block_info)
2299                 vfree(dev->block_info);
2300         else
2301                 kfree(dev->block_info);
2302
2303         dev->block_info_alt = 0;
2304
2305         dev->block_info = NULL;
2306
2307         if (dev->chunk_bits_alt && dev->chunk_bits)
2308                 vfree(dev->chunk_bits);
2309         else
2310                 kfree(dev->chunk_bits);
2311         dev->chunk_bits_alt = 0;
2312         dev->chunk_bits = NULL;
2313 }
2314
2315 static int yaffs_init_blocks(struct yaffs_dev *dev)
2316 {
2317         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
2318
2319         dev->block_info = NULL;
2320         dev->chunk_bits = NULL;
2321         dev->alloc_block = -1;  /* force it to get a new one */
2322
2323         /* If the first allocation strategy fails, thry the alternate one */
2324         dev->block_info =
2325                 kmalloc(n_blocks * sizeof(struct yaffs_block_info), GFP_NOFS);
2326         if (!dev->block_info) {
2327                 dev->block_info =
2328                     vmalloc(n_blocks * sizeof(struct yaffs_block_info));
2329                 dev->block_info_alt = 1;
2330         } else {
2331                 dev->block_info_alt = 0;
2332         }
2333
2334         if (!dev->block_info)
2335                 goto alloc_error;
2336
2337         /* Set up dynamic blockinfo stuff. Round up bytes. */
2338         dev->chunk_bit_stride = (dev->param.chunks_per_block + 7) / 8;
2339         dev->chunk_bits =
2340                 kmalloc(dev->chunk_bit_stride * n_blocks, GFP_NOFS);
2341         if (!dev->chunk_bits) {
2342                 dev->chunk_bits =
2343                     vmalloc(dev->chunk_bit_stride * n_blocks);
2344                 dev->chunk_bits_alt = 1;
2345         } else {
2346                 dev->chunk_bits_alt = 0;
2347         }
2348         if (!dev->chunk_bits)
2349                 goto alloc_error;
2350
2351
2352         memset(dev->block_info, 0, n_blocks * sizeof(struct yaffs_block_info));
2353         memset(dev->chunk_bits, 0, dev->chunk_bit_stride * n_blocks);
2354         return YAFFS_OK;
2355
2356 alloc_error:
2357         yaffs_deinit_blocks(dev);
2358         return YAFFS_FAIL;
2359 }
2360
2361
2362 void yaffs_block_became_dirty(struct yaffs_dev *dev, int block_no)
2363 {
2364         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block_no);
2365         int erased_ok = 0;
2366         int i;
2367
2368         /* If the block is still healthy erase it and mark as clean.
2369          * If the block has had a data failure, then retire it.
2370          */
2371
2372         yaffs_trace(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
2373                 "yaffs_block_became_dirty block %d state %d %s",
2374                 block_no, bi->block_state,
2375                 (bi->needs_retiring) ? "needs retiring" : "");
2376
2377         yaffs2_clear_oldest_dirty_seq(dev, bi);
2378
2379         bi->block_state = YAFFS_BLOCK_STATE_DIRTY;
2380
2381         /* If this is the block being garbage collected then stop gc'ing */
2382         if (block_no == dev->gc_block)
2383                 dev->gc_block = 0;
2384
2385         /* If this block is currently the best candidate for gc
2386          * then drop as a candidate */
2387         if (block_no == dev->gc_dirtiest) {
2388                 dev->gc_dirtiest = 0;
2389                 dev->gc_pages_in_use = 0;
2390         }
2391
2392         if (!bi->needs_retiring) {
2393                 yaffs2_checkpt_invalidate(dev);
2394                 erased_ok = yaffs_erase_block(dev, block_no);
2395                 if (!erased_ok) {
2396                         dev->n_erase_failures++;
2397                         yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
2398                           "**>> Erasure failed %d", block_no);
2399                 }
2400         }
2401
2402         /* Verify erasure if needed */
2403         if (erased_ok &&
2404             ((yaffs_trace_mask & YAFFS_TRACE_ERASE) ||
2405              !yaffs_skip_verification(dev))) {
2406                 for (i = 0; i < dev->param.chunks_per_block; i++) {
2407                         if (!yaffs_check_chunk_erased(dev,
2408                                 block_no * dev->param.chunks_per_block + i)) {
2409                                 yaffs_trace(YAFFS_TRACE_ERROR,
2410                                         ">>Block %d erasure supposedly OK, but chunk %d not erased",
2411                                         block_no, i);
2412                         }
2413                 }
2414         }
2415
2416         if (!erased_ok) {
2417                 /* We lost a block of free space */
2418                 dev->n_free_chunks -= dev->param.chunks_per_block;
2419                 yaffs_retire_block(dev, block_no);
2420                 yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
2421                         "**>> Block %d retired", block_no);
2422                 return;
2423         }
2424
2425         /* Clean it up... */
2426         bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
2427         bi->seq_number = 0;
2428         dev->n_erased_blocks++;
2429         bi->pages_in_use = 0;
2430         bi->soft_del_pages = 0;
2431         bi->has_shrink_hdr = 0;
2432         bi->skip_erased_check = 1;      /* Clean, so no need to check */
2433         bi->gc_prioritise = 0;
2434         bi->has_summary = 0;
2435
2436         yaffs_clear_chunk_bits(dev, block_no);
2437
2438         yaffs_trace(YAFFS_TRACE_ERASE, "Erased block %d", block_no);
2439 }
2440
2441 static inline int yaffs_gc_process_chunk(struct yaffs_dev *dev,
2442                                         struct yaffs_block_info *bi,
2443                                         int old_chunk, u8 *buffer)
2444 {
2445         int new_chunk;
2446         int mark_flash = 1;
2447         struct yaffs_ext_tags tags;
2448         struct yaffs_obj *object;
2449         int matching_chunk;
2450         int ret_val = YAFFS_OK;
2451
2452         memset(&tags, 0, sizeof(tags));
2453         yaffs_rd_chunk_tags_nand(dev, old_chunk,
2454                                  buffer, &tags);
2455         object = yaffs_find_by_number(dev, tags.obj_id);
2456
2457         yaffs_trace(YAFFS_TRACE_GC_DETAIL,
2458                 "Collecting chunk in block %d, %d %d %d ",
2459                 dev->gc_chunk, tags.obj_id,
2460                 tags.chunk_id, tags.n_bytes);
2461
2462         if (object && !yaffs_skip_verification(dev)) {
2463                 if (tags.chunk_id == 0)
2464                         matching_chunk =
2465                             object->hdr_chunk;
2466                 else if (object->soft_del)
2467                         /* Defeat the test */
2468                         matching_chunk = old_chunk;
2469                 else
2470                         matching_chunk =
2471                             yaffs_find_chunk_in_file
2472                             (object, tags.chunk_id,
2473                              NULL);
2474
2475                 if (old_chunk != matching_chunk)
2476                         yaffs_trace(YAFFS_TRACE_ERROR,
2477                                 "gc: page in gc mismatch: %d %d %d %d",
2478                                 old_chunk,
2479                                 matching_chunk,
2480                                 tags.obj_id,
2481                                 tags.chunk_id);
2482         }
2483
2484         if (!object) {
2485                 yaffs_trace(YAFFS_TRACE_ERROR,
2486                         "page %d in gc has no object: %d %d %d ",
2487                         old_chunk,
2488                         tags.obj_id, tags.chunk_id,
2489                         tags.n_bytes);
2490         }
2491
2492         if (object &&
2493             object->deleted &&
2494             object->soft_del && tags.chunk_id != 0) {
2495                 /* Data chunk in a soft deleted file,
2496                  * throw it away.
2497                  * It's a soft deleted data chunk,
2498                  * No need to copy this, just forget
2499                  * about it and fix up the object.
2500                  */
2501
2502                 /* Free chunks already includes
2503                  * softdeleted chunks, how ever this
2504                  * chunk is going to soon be really
2505                  * deleted which will increment free
2506                  * chunks. We have to decrement free
2507                  * chunks so this works out properly.
2508                  */
2509                 dev->n_free_chunks--;
2510                 bi->soft_del_pages--;
2511
2512                 object->n_data_chunks--;
2513                 if (object->n_data_chunks <= 0) {
2514                         /* remeber to clean up obj */
2515                         dev->gc_cleanup_list[dev->n_clean_ups] = tags.obj_id;
2516                         dev->n_clean_ups++;
2517                 }
2518                 mark_flash = 0;
2519         } else if (object) {
2520                 /* It's either a data chunk in a live
2521                  * file or an ObjectHeader, so we're
2522                  * interested in it.
2523                  * NB Need to keep the ObjectHeaders of
2524                  * deleted files until the whole file
2525                  * has been deleted off
2526                  */
2527                 tags.serial_number++;
2528                 dev->n_gc_copies++;
2529
2530                 if (tags.chunk_id == 0) {
2531                         /* It is an object Id,
2532                          * We need to nuke the
2533                          * shrinkheader flags since its
2534                          * work is done.
2535                          * Also need to clean up
2536                          * shadowing.
2537                          */
2538                         struct yaffs_obj_hdr *oh;
2539                         oh = (struct yaffs_obj_hdr *) buffer;
2540
2541                         oh->is_shrink = 0;
2542                         tags.extra_is_shrink = 0;
2543                         oh->shadows_obj = 0;
2544                         oh->inband_shadowed_obj_id = 0;
2545                         tags.extra_shadows = 0;
2546
2547                         /* Update file size */
2548                         if (object->variant_type == YAFFS_OBJECT_TYPE_FILE) {
2549                                 yaffs_oh_size_load(oh,
2550                                     object->variant.file_variant.file_size);
2551                                 tags.extra_file_size =
2552                                     object->variant.file_variant.file_size;
2553                         }
2554
2555                         yaffs_verify_oh(object, oh, &tags, 1);
2556                         new_chunk =
2557                             yaffs_write_new_chunk(dev, (u8 *) oh, &tags, 1);
2558                 } else {
2559                         new_chunk =
2560                             yaffs_write_new_chunk(dev, buffer, &tags, 1);
2561                 }
2562
2563                 if (new_chunk < 0) {
2564                         ret_val = YAFFS_FAIL;
2565                 } else {
2566
2567                         /* Now fix up the Tnodes etc. */
2568
2569                         if (tags.chunk_id == 0) {
2570                                 /* It's a header */
2571                                 object->hdr_chunk = new_chunk;
2572                                 object->serial = tags.serial_number;
2573                         } else {
2574                                 /* It's a data chunk */
2575                                 yaffs_put_chunk_in_file(object, tags.chunk_id,
2576                                                         new_chunk, 0);
2577                         }
2578                 }
2579         }
2580         if (ret_val == YAFFS_OK)
2581                 yaffs_chunk_del(dev, old_chunk, mark_flash, __LINE__);
2582         return ret_val;
2583 }
2584
2585 static int yaffs_gc_block(struct yaffs_dev *dev, int block, int whole_block)
2586 {
2587         int old_chunk;
2588         int ret_val = YAFFS_OK;
2589         int i;
2590         int is_checkpt_block;
2591         int max_copies;
2592         int chunks_before = yaffs_get_erased_chunks(dev);
2593         int chunks_after;
2594         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block);
2595
2596         is_checkpt_block = (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT);
2597
2598         yaffs_trace(YAFFS_TRACE_TRACING,
2599                 "Collecting block %d, in use %d, shrink %d, whole_block %d",
2600                 block, bi->pages_in_use, bi->has_shrink_hdr,
2601                 whole_block);
2602
2603         /*yaffs_verify_free_chunks(dev); */
2604
2605         if (bi->block_state == YAFFS_BLOCK_STATE_FULL)
2606                 bi->block_state = YAFFS_BLOCK_STATE_COLLECTING;
2607
2608         bi->has_shrink_hdr = 0; /* clear the flag so that the block can erase */
2609
2610         dev->gc_disable = 1;
2611
2612         yaffs_summary_gc(dev, block);
2613
2614         if (is_checkpt_block || !yaffs_still_some_chunks(dev, block)) {
2615                 yaffs_trace(YAFFS_TRACE_TRACING,
2616                         "Collecting block %d that has no chunks in use",
2617                         block);
2618                 yaffs_block_became_dirty(dev, block);
2619         } else {
2620
2621                 u8 *buffer = yaffs_get_temp_buffer(dev);
2622
2623                 yaffs_verify_blk(dev, bi, block);
2624
2625                 max_copies = (whole_block) ? dev->param.chunks_per_block : 5;
2626                 old_chunk = block * dev->param.chunks_per_block + dev->gc_chunk;
2627
2628                 for (/* init already done */ ;
2629                      ret_val == YAFFS_OK &&
2630                      dev->gc_chunk < dev->param.chunks_per_block &&
2631                      (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) &&
2632                      max_copies > 0;
2633                      dev->gc_chunk++, old_chunk++) {
2634                         if (yaffs_check_chunk_bit(dev, block, dev->gc_chunk)) {
2635                                 /* Page is in use and might need to be copied */
2636                                 max_copies--;
2637                                 ret_val = yaffs_gc_process_chunk(dev, bi,
2638                                                         old_chunk, buffer);
2639                         }
2640                 }
2641                 yaffs_release_temp_buffer(dev, buffer);
2642         }
2643
2644         yaffs_verify_collected_blk(dev, bi, block);
2645
2646         if (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
2647                 /*
2648                  * The gc did not complete. Set block state back to FULL
2649                  * because checkpointing does not restore gc.
2650                  */
2651                 bi->block_state = YAFFS_BLOCK_STATE_FULL;
2652         } else {
2653                 /* The gc completed. */
2654                 /* Do any required cleanups */
2655                 for (i = 0; i < dev->n_clean_ups; i++) {
2656                         /* Time to delete the file too */
2657                         struct yaffs_obj *object =
2658                             yaffs_find_by_number(dev, dev->gc_cleanup_list[i]);
2659                         if (object) {
2660                                 yaffs_free_tnode(dev,
2661                                           object->variant.file_variant.top);
2662                                 object->variant.file_variant.top = NULL;
2663                                 yaffs_trace(YAFFS_TRACE_GC,
2664                                         "yaffs: About to finally delete object %d",
2665                                         object->obj_id);
2666                                 yaffs_generic_obj_del(object);
2667                                 object->my_dev->n_deleted_files--;
2668                         }
2669
2670                 }
2671                 chunks_after = yaffs_get_erased_chunks(dev);
2672                 if (chunks_before >= chunks_after)
2673                         yaffs_trace(YAFFS_TRACE_GC,
2674                                 "gc did not increase free chunks before %d after %d",
2675                                 chunks_before, chunks_after);
2676                 dev->gc_block = 0;
2677                 dev->gc_chunk = 0;
2678                 dev->n_clean_ups = 0;
2679         }
2680
2681         dev->gc_disable = 0;
2682
2683         return ret_val;
2684 }
2685
2686 /*
2687  * find_gc_block() selects the dirtiest block (or close enough)
2688  * for garbage collection.
2689  */
2690
2691 static unsigned yaffs_find_gc_block(struct yaffs_dev *dev,
2692                                     int aggressive, int background)
2693 {
2694         int i;
2695         int iterations;
2696         unsigned selected = 0;
2697         int prioritised = 0;
2698         int prioritised_exist = 0;
2699         struct yaffs_block_info *bi;
2700         int threshold;
2701
2702         /* First let's see if we need to grab a prioritised block */
2703         if (dev->has_pending_prioritised_gc && !aggressive) {
2704                 dev->gc_dirtiest = 0;
2705                 bi = dev->block_info;
2706                 for (i = dev->internal_start_block;
2707                      i <= dev->internal_end_block && !selected; i++) {
2708
2709                         if (bi->gc_prioritise) {
2710                                 prioritised_exist = 1;
2711                                 if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2712                                     yaffs_block_ok_for_gc(dev, bi)) {
2713                                         selected = i;
2714                                         prioritised = 1;
2715                                 }
2716                         }
2717                         bi++;
2718                 }
2719
2720                 /*
2721                  * If there is a prioritised block and none was selected then
2722                  * this happened because there is at least one old dirty block
2723                  * gumming up the works. Let's gc the oldest dirty block.
2724                  */
2725
2726                 if (prioritised_exist &&
2727                     !selected && dev->oldest_dirty_block > 0)
2728                         selected = dev->oldest_dirty_block;
2729
2730                 if (!prioritised_exist) /* None found, so we can clear this */
2731                         dev->has_pending_prioritised_gc = 0;
2732         }
2733
2734         /* If we're doing aggressive GC then we are happy to take a less-dirty
2735          * block, and search harder.
2736          * else (leasurely gc), then we only bother to do this if the
2737          * block has only a few pages in use.
2738          */
2739
2740         if (!selected) {
2741                 int pages_used;
2742                 int n_blocks =
2743                     dev->internal_end_block - dev->internal_start_block + 1;
2744                 if (aggressive) {
2745                         threshold = dev->param.chunks_per_block;
2746                         iterations = n_blocks;
2747                 } else {
2748                         int max_threshold;
2749
2750                         if (background)
2751                                 max_threshold = dev->param.chunks_per_block / 2;
2752                         else
2753                                 max_threshold = dev->param.chunks_per_block / 8;
2754
2755                         if (max_threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2756                                 max_threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2757
2758                         threshold = background ? (dev->gc_not_done + 2) * 2 : 0;
2759                         if (threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2760                                 threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2761                         if (threshold > max_threshold)
2762                                 threshold = max_threshold;
2763
2764                         iterations = n_blocks / 16 + 1;
2765                         if (iterations > 100)
2766                                 iterations = 100;
2767                 }
2768
2769                 for (i = 0;
2770                      i < iterations &&
2771                      (dev->gc_dirtiest < 1 ||
2772                       dev->gc_pages_in_use > YAFFS_GC_GOOD_ENOUGH);
2773                      i++) {
2774                         dev->gc_block_finder++;
2775                         if (dev->gc_block_finder < dev->internal_start_block ||
2776                             dev->gc_block_finder > dev->internal_end_block)
2777                                 dev->gc_block_finder =
2778                                     dev->internal_start_block;
2779
2780                         bi = yaffs_get_block_info(dev, dev->gc_block_finder);
2781
2782                         pages_used = bi->pages_in_use - bi->soft_del_pages;
2783
2784                         if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2785                             pages_used < dev->param.chunks_per_block &&
2786                             (dev->gc_dirtiest < 1 ||
2787                              pages_used < dev->gc_pages_in_use) &&
2788                             yaffs_block_ok_for_gc(dev, bi)) {
2789                                 dev->gc_dirtiest = dev->gc_block_finder;
2790                                 dev->gc_pages_in_use = pages_used;
2791                         }
2792                 }
2793
2794                 if (dev->gc_dirtiest > 0 && dev->gc_pages_in_use <= threshold)
2795                         selected = dev->gc_dirtiest;
2796         }
2797
2798         /*
2799          * If nothing has been selected for a while, try the oldest dirty
2800          * because that's gumming up the works.
2801          */
2802
2803         if (!selected && dev->param.is_yaffs2 &&
2804             dev->gc_not_done >= (background ? 10 : 20)) {
2805                 yaffs2_find_oldest_dirty_seq(dev);
2806                 if (dev->oldest_dirty_block > 0) {
2807                         selected = dev->oldest_dirty_block;
2808                         dev->gc_dirtiest = selected;
2809                         dev->oldest_dirty_gc_count++;
2810                         bi = yaffs_get_block_info(dev, selected);
2811                         dev->gc_pages_in_use =
2812                             bi->pages_in_use - bi->soft_del_pages;
2813                 } else {
2814                         dev->gc_not_done = 0;
2815                 }
2816         }
2817
2818         if (selected) {
2819                 yaffs_trace(YAFFS_TRACE_GC,
2820                         "GC Selected block %d with %d free, prioritised:%d",
2821                         selected,
2822                         dev->param.chunks_per_block - dev->gc_pages_in_use,
2823                         prioritised);
2824
2825                 dev->n_gc_blocks++;
2826                 if (background)
2827                         dev->bg_gcs++;
2828
2829                 dev->gc_dirtiest = 0;
2830                 dev->gc_pages_in_use = 0;
2831                 dev->gc_not_done = 0;
2832                 if (dev->refresh_skip > 0)
2833                         dev->refresh_skip--;
2834         } else {
2835                 dev->gc_not_done++;
2836                 yaffs_trace(YAFFS_TRACE_GC,
2837                         "GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s",
2838                         dev->gc_block_finder, dev->gc_not_done, threshold,
2839                         dev->gc_dirtiest, dev->gc_pages_in_use,
2840                         dev->oldest_dirty_block, background ? " bg" : "");
2841         }
2842
2843         return selected;
2844 }
2845
2846 /* New garbage collector
2847  * If we're very low on erased blocks then we do aggressive garbage collection
2848  * otherwise we do "leasurely" garbage collection.
2849  * Aggressive gc looks further (whole array) and will accept less dirty blocks.
2850  * Passive gc only inspects smaller areas and only accepts more dirty blocks.
2851  *
2852  * The idea is to help clear out space in a more spread-out manner.
2853  * Dunno if it really does anything useful.
2854  */
2855 static int yaffs_check_gc(struct yaffs_dev *dev, int background)
2856 {
2857         int aggressive = 0;
2858         int gc_ok = YAFFS_OK;
2859         int max_tries = 0;
2860         int min_erased;
2861         int erased_chunks;
2862         int checkpt_block_adjust;
2863
2864         if (dev->param.gc_control_fn &&
2865                 (dev->param.gc_control_fn(dev) & 1) == 0)
2866                 return YAFFS_OK;
2867
2868         if (dev->gc_disable)
2869                 /* Bail out so we don't get recursive gc */
2870                 return YAFFS_OK;
2871
2872         /* This loop should pass the first time.
2873          * Only loops here if the collection does not increase space.
2874          */
2875
2876         do {
2877                 max_tries++;
2878
2879                 checkpt_block_adjust = yaffs_calc_checkpt_blocks_required(dev);
2880
2881                 min_erased =
2882                     dev->param.n_reserved_blocks + checkpt_block_adjust + 1;
2883                 erased_chunks =
2884                     dev->n_erased_blocks * dev->param.chunks_per_block;
2885
2886                 /* If we need a block soon then do aggressive gc. */
2887                 if (dev->n_erased_blocks < min_erased)
2888                         aggressive = 1;
2889                 else {
2890                         if (!background
2891                             && erased_chunks > (dev->n_free_chunks / 4))
2892                                 break;
2893
2894                         if (dev->gc_skip > 20)
2895                                 dev->gc_skip = 20;
2896                         if (erased_chunks < dev->n_free_chunks / 2 ||
2897                             dev->gc_skip < 1 || background)
2898                                 aggressive = 0;
2899                         else {
2900                                 dev->gc_skip--;
2901                                 break;
2902                         }
2903                 }
2904
2905                 dev->gc_skip = 5;
2906
2907                 /* If we don't already have a block being gc'd then see if we
2908                  * should start another */
2909
2910                 if (dev->gc_block < 1 && !aggressive) {
2911                         dev->gc_block = yaffs2_find_refresh_block(dev);
2912                         dev->gc_chunk = 0;
2913                         dev->n_clean_ups = 0;
2914                 }
2915                 if (dev->gc_block < 1) {
2916                         dev->gc_block =
2917                             yaffs_find_gc_block(dev, aggressive, background);
2918                         dev->gc_chunk = 0;
2919                         dev->n_clean_ups = 0;
2920                 }
2921
2922                 if (dev->gc_block > 0) {
2923                         dev->all_gcs++;
2924                         if (!aggressive)
2925                                 dev->passive_gc_count++;
2926
2927                         yaffs_trace(YAFFS_TRACE_GC,
2928                                 "yaffs: GC n_erased_blocks %d aggressive %d",
2929                                 dev->n_erased_blocks, aggressive);
2930
2931                         gc_ok = yaffs_gc_block(dev, dev->gc_block, aggressive);
2932                 }
2933
2934                 if (dev->n_erased_blocks < (dev->param.n_reserved_blocks) &&
2935                     dev->gc_block > 0) {
2936                         yaffs_trace(YAFFS_TRACE_GC,
2937                                 "yaffs: GC !!!no reclaim!!! n_erased_blocks %d after try %d block %d",
2938                                 dev->n_erased_blocks, max_tries,
2939                                 dev->gc_block);
2940                 }
2941         } while ((dev->n_erased_blocks < dev->param.n_reserved_blocks) &&
2942                  (dev->gc_block > 0) && (max_tries < 2));
2943
2944         return aggressive ? gc_ok : YAFFS_OK;
2945 }
2946
2947 /*
2948  * yaffs_bg_gc()
2949  * Garbage collects. Intended to be called from a background thread.
2950  * Returns non-zero if at least half the free chunks are erased.
2951  */
2952 int yaffs_bg_gc(struct yaffs_dev *dev, unsigned urgency)
2953 {
2954         int erased_chunks = dev->n_erased_blocks * dev->param.chunks_per_block;
2955
2956         yaffs_trace(YAFFS_TRACE_BACKGROUND, "Background gc %u", urgency);
2957
2958         yaffs_check_gc(dev, 1);
2959         return erased_chunks > dev->n_free_chunks / 2;
2960 }
2961
2962 /*-------------------- Data file manipulation -----------------*/
2963
2964 static int yaffs_rd_data_obj(struct yaffs_obj *in, int inode_chunk, u8 * buffer)
2965 {
2966         int nand_chunk = yaffs_find_chunk_in_file(in, inode_chunk, NULL);
2967
2968         if (nand_chunk >= 0)
2969                 return yaffs_rd_chunk_tags_nand(in->my_dev, nand_chunk,
2970                                                 buffer, NULL);
2971         else {
2972                 yaffs_trace(YAFFS_TRACE_NANDACCESS,
2973                         "Chunk %d not found zero instead",
2974                         nand_chunk);
2975                 /* get sane (zero) data if you read a hole */
2976                 memset(buffer, 0, in->my_dev->data_bytes_per_chunk);
2977                 return 0;
2978         }
2979
2980 }
2981
2982 void yaffs_chunk_del(struct yaffs_dev *dev, int chunk_id, int mark_flash,
2983                      int lyn)
2984 {
2985         int block;
2986         int page;
2987         struct yaffs_ext_tags tags;
2988         struct yaffs_block_info *bi;
2989
2990         if (chunk_id <= 0)
2991                 return;
2992
2993         dev->n_deletions++;
2994         block = chunk_id / dev->param.chunks_per_block;
2995         page = chunk_id % dev->param.chunks_per_block;
2996
2997         if (!yaffs_check_chunk_bit(dev, block, page))
2998                 yaffs_trace(YAFFS_TRACE_VERIFY,
2999                         "Deleting invalid chunk %d", chunk_id);
3000
3001         bi = yaffs_get_block_info(dev, block);
3002
3003         yaffs2_update_oldest_dirty_seq(dev, block, bi);
3004
3005         yaffs_trace(YAFFS_TRACE_DELETION,
3006                 "line %d delete of chunk %d",
3007                 lyn, chunk_id);
3008
3009         if (!dev->param.is_yaffs2 && mark_flash &&
3010             bi->block_state != YAFFS_BLOCK_STATE_COLLECTING) {
3011
3012                 memset(&tags, 0, sizeof(tags));
3013                 tags.is_deleted = 1;
3014                 yaffs_wr_chunk_tags_nand(dev, chunk_id, NULL, &tags);
3015                 yaffs_handle_chunk_update(dev, chunk_id, &tags);
3016         } else {
3017                 dev->n_unmarked_deletions++;
3018         }
3019
3020         /* Pull out of the management area.
3021          * If the whole block became dirty, this will kick off an erasure.
3022          */
3023         if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING ||
3024             bi->block_state == YAFFS_BLOCK_STATE_FULL ||
3025             bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
3026             bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
3027                 dev->n_free_chunks++;
3028                 yaffs_clear_chunk_bit(dev, block, page);
3029                 bi->pages_in_use--;
3030
3031                 if (bi->pages_in_use == 0 &&
3032                     !bi->has_shrink_hdr &&
3033                     bi->block_state != YAFFS_BLOCK_STATE_ALLOCATING &&
3034                     bi->block_state != YAFFS_BLOCK_STATE_NEEDS_SCAN) {
3035                         yaffs_block_became_dirty(dev, block);
3036                 }
3037         }
3038 }
3039
3040 static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
3041                              const u8 *buffer, int n_bytes, int use_reserve)
3042 {
3043         /* Find old chunk Need to do this to get serial number
3044          * Write new one and patch into tree.
3045          * Invalidate old tags.
3046          */
3047
3048         int prev_chunk_id;
3049         struct yaffs_ext_tags prev_tags;
3050         int new_chunk_id;
3051         struct yaffs_ext_tags new_tags;
3052         struct yaffs_dev *dev = in->my_dev;
3053
3054         yaffs_check_gc(dev, 0);
3055
3056         /* Get the previous chunk at this location in the file if it exists.
3057          * If it does not exist then put a zero into the tree. This creates
3058          * the tnode now, rather than later when it is harder to clean up.
3059          */
3060         prev_chunk_id = yaffs_find_chunk_in_file(in, inode_chunk, &prev_tags);
3061         if (prev_chunk_id < 1 &&
3062             !yaffs_put_chunk_in_file(in, inode_chunk, 0, 0))
3063                 return 0;
3064
3065         /* Set up new tags */
3066         memset(&new_tags, 0, sizeof(new_tags));
3067
3068         new_tags.chunk_id = inode_chunk;
3069         new_tags.obj_id = in->obj_id;
3070         new_tags.serial_number =
3071             (prev_chunk_id > 0) ? prev_tags.serial_number + 1 : 1;
3072         new_tags.n_bytes = n_bytes;
3073
3074         if (n_bytes < 1 || n_bytes > dev->param.total_bytes_per_chunk) {
3075                 yaffs_trace(YAFFS_TRACE_ERROR,
3076                   "Writing %d bytes to chunk!!!!!!!!!",
3077                    n_bytes);
3078                 BUG();
3079         }
3080
3081         new_chunk_id =
3082             yaffs_write_new_chunk(dev, buffer, &new_tags, use_reserve);
3083
3084         if (new_chunk_id > 0) {
3085                 yaffs_put_chunk_in_file(in, inode_chunk, new_chunk_id, 0);
3086
3087                 if (prev_chunk_id > 0)
3088                         yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
3089
3090                 yaffs_verify_file_sane(in);
3091         }
3092         return new_chunk_id;
3093
3094 }
3095
3096
3097
3098 static int yaffs_do_xattrib_mod(struct yaffs_obj *obj, int set,
3099                                 const YCHAR *name, const void *value, int size,
3100                                 int flags)
3101 {
3102         struct yaffs_xattr_mod xmod;
3103         int result;
3104
3105         xmod.set = set;
3106         xmod.name = name;
3107         xmod.data = value;
3108         xmod.size = size;
3109         xmod.flags = flags;
3110         xmod.result = -ENOSPC;
3111
3112         result = yaffs_update_oh(obj, NULL, 0, 0, 0, &xmod);
3113
3114         if (result > 0)
3115                 return xmod.result;
3116         else
3117                 return -ENOSPC;
3118 }
3119
3120 static int yaffs_apply_xattrib_mod(struct yaffs_obj *obj, char *buffer,
3121                                    struct yaffs_xattr_mod *xmod)
3122 {
3123         int retval = 0;
3124         int x_offs = sizeof(struct yaffs_obj_hdr);
3125         struct yaffs_dev *dev = obj->my_dev;
3126         int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
3127         char *x_buffer = buffer + x_offs;
3128
3129         if (xmod->set)
3130                 retval =
3131                     nval_set(x_buffer, x_size, xmod->name, xmod->data,
3132                              xmod->size, xmod->flags);
3133         else
3134                 retval = nval_del(x_buffer, x_size, xmod->name);
3135
3136         obj->has_xattr = nval_hasvalues(x_buffer, x_size);
3137         obj->xattr_known = 1;
3138         xmod->result = retval;
3139
3140         return retval;
3141 }
3142
3143 static int yaffs_do_xattrib_fetch(struct yaffs_obj *obj, const YCHAR *name,
3144                                   void *value, int size)
3145 {
3146         char *buffer = NULL;
3147         int result;
3148         struct yaffs_ext_tags tags;
3149         struct yaffs_dev *dev = obj->my_dev;
3150         int x_offs = sizeof(struct yaffs_obj_hdr);
3151         int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
3152         char *x_buffer;
3153         int retval = 0;
3154
3155         if (obj->hdr_chunk < 1)
3156                 return -ENODATA;
3157
3158         /* If we know that the object has no xattribs then don't do all the
3159          * reading and parsing.
3160          */
3161         if (obj->xattr_known && !obj->has_xattr) {
3162                 if (name)
3163                         return -ENODATA;
3164                 else
3165                         return 0;
3166         }
3167
3168         buffer = (char *)yaffs_get_temp_buffer(dev);
3169         if (!buffer)
3170                 return -ENOMEM;
3171
3172         result =
3173             yaffs_rd_chunk_tags_nand(dev, obj->hdr_chunk, (u8 *) buffer, &tags);
3174
3175         if (result != YAFFS_OK)
3176                 retval = -ENOENT;
3177         else {
3178                 x_buffer = buffer + x_offs;
3179
3180                 if (!obj->xattr_known) {
3181                         obj->has_xattr = nval_hasvalues(x_buffer, x_size);
3182                         obj->xattr_known = 1;
3183                 }
3184
3185                 if (name)
3186                         retval = nval_get(x_buffer, x_size, name, value, size);
3187                 else
3188                         retval = nval_list(x_buffer, x_size, value, size);
3189         }
3190         yaffs_release_temp_buffer(dev, (u8 *) buffer);
3191         return retval;
3192 }
3193
3194 int yaffs_set_xattrib(struct yaffs_obj *obj, const YCHAR * name,
3195                       const void *value, int size, int flags)
3196 {
3197         return yaffs_do_xattrib_mod(obj, 1, name, value, size, flags);
3198 }
3199
3200 int yaffs_remove_xattrib(struct yaffs_obj *obj, const YCHAR * name)
3201 {
3202         return yaffs_do_xattrib_mod(obj, 0, name, NULL, 0, 0);
3203 }
3204
3205 int yaffs_get_xattrib(struct yaffs_obj *obj, const YCHAR * name, void *value,
3206                       int size)
3207 {
3208         return yaffs_do_xattrib_fetch(obj, name, value, size);
3209 }
3210
3211 int yaffs_list_xattrib(struct yaffs_obj *obj, char *buffer, int size)
3212 {
3213         return yaffs_do_xattrib_fetch(obj, NULL, buffer, size);
3214 }
3215
3216 static void yaffs_check_obj_details_loaded(struct yaffs_obj *in)
3217 {
3218         u8 *buf;
3219         struct yaffs_obj_hdr *oh;
3220         struct yaffs_dev *dev;
3221         struct yaffs_ext_tags tags;
3222         int result;
3223         int alloc_failed = 0;
3224
3225         if (!in || !in->lazy_loaded || in->hdr_chunk < 1)
3226                 return;
3227
3228         dev = in->my_dev;
3229         in->lazy_loaded = 0;
3230         buf = yaffs_get_temp_buffer(dev);
3231
3232         result = yaffs_rd_chunk_tags_nand(dev, in->hdr_chunk, buf, &tags);
3233         oh = (struct yaffs_obj_hdr *)buf;
3234
3235         in->yst_mode = oh->yst_mode;
3236         yaffs_load_attribs(in, oh);
3237         yaffs_set_obj_name_from_oh(in, oh);
3238
3239         if (in->variant_type == YAFFS_OBJECT_TYPE_SYMLINK) {
3240                 in->variant.symlink_variant.alias =
3241                     yaffs_clone_str(oh->alias);
3242                 if (!in->variant.symlink_variant.alias)
3243                         alloc_failed = 1;       /* Not returned */
3244         }
3245         yaffs_release_temp_buffer(dev, buf);
3246 }
3247
3248 /* UpdateObjectHeader updates the header on NAND for an object.
3249  * If name is not NULL, then that new name is used.
3250  */
3251 int yaffs_update_oh(struct yaffs_obj *in, const YCHAR *name, int force,
3252                     int is_shrink, int shadows, struct yaffs_xattr_mod *xmod)
3253 {
3254
3255         struct yaffs_block_info *bi;
3256         struct yaffs_dev *dev = in->my_dev;
3257         int prev_chunk_id;
3258         int ret_val = 0;
3259         int result = 0;
3260         int new_chunk_id;
3261         struct yaffs_ext_tags new_tags;
3262         struct yaffs_ext_tags old_tags;
3263         const YCHAR *alias = NULL;
3264         u8 *buffer = NULL;
3265         YCHAR old_name[YAFFS_MAX_NAME_LENGTH + 1];
3266         struct yaffs_obj_hdr *oh = NULL;
3267         loff_t file_size = 0;
3268
3269         strcpy(old_name, _Y("silly old name"));
3270
3271         if (in->fake && in != dev->root_dir && !force && !xmod)
3272                 return ret_val;
3273
3274         yaffs_check_gc(dev, 0);
3275         yaffs_check_obj_details_loaded(in);
3276
3277         buffer = yaffs_get_temp_buffer(in->my_dev);
3278         oh = (struct yaffs_obj_hdr *)buffer;
3279
3280         prev_chunk_id = in->hdr_chunk;
3281
3282         if (prev_chunk_id > 0) {
3283                 result = yaffs_rd_chunk_tags_nand(dev, prev_chunk_id,
3284                                                   buffer, &old_tags);
3285
3286                 yaffs_verify_oh(in, oh, &old_tags, 0);
3287                 memcpy(old_name, oh->name, sizeof(oh->name));
3288                 memset(buffer, 0xff, sizeof(struct yaffs_obj_hdr));
3289         } else {
3290                 memset(buffer, 0xff, dev->data_bytes_per_chunk);
3291         }
3292
3293         oh->type = in->variant_type;
3294         oh->yst_mode = in->yst_mode;
3295         oh->shadows_obj = oh->inband_shadowed_obj_id = shadows;
3296
3297         yaffs_load_attribs_oh(oh, in);
3298
3299         if (in->parent)
3300                 oh->parent_obj_id = in->parent->obj_id;
3301         else
3302                 oh->parent_obj_id = 0;
3303
3304         if (name && *name) {
3305                 memset(oh->name, 0, sizeof(oh->name));
3306                 yaffs_load_oh_from_name(dev, oh->name, name);
3307         } else if (prev_chunk_id > 0) {
3308                 memcpy(oh->name, old_name, sizeof(oh->name));
3309         } else {
3310                 memset(oh->name, 0, sizeof(oh->name));
3311         }
3312
3313         oh->is_shrink = is_shrink;
3314
3315         switch (in->variant_type) {
3316         case YAFFS_OBJECT_TYPE_UNKNOWN:
3317                 /* Should not happen */
3318                 break;
3319         case YAFFS_OBJECT_TYPE_FILE:
3320                 if (oh->parent_obj_id != YAFFS_OBJECTID_DELETED &&
3321                     oh->parent_obj_id != YAFFS_OBJECTID_UNLINKED)
3322                         file_size = in->variant.file_variant.file_size;
3323                 yaffs_oh_size_load(oh, file_size);
3324                 break;
3325         case YAFFS_OBJECT_TYPE_HARDLINK:
3326                 oh->equiv_id = in->variant.hardlink_variant.equiv_id;
3327                 break;
3328         case YAFFS_OBJECT_TYPE_SPECIAL:
3329                 /* Do nothing */
3330                 break;
3331         case YAFFS_OBJECT_TYPE_DIRECTORY:
3332                 /* Do nothing */
3333                 break;
3334         case YAFFS_OBJECT_TYPE_SYMLINK:
3335                 alias = in->variant.symlink_variant.alias;
3336                 if (!alias)
3337                         alias = _Y("no alias");
3338                 strncpy(oh->alias, alias, YAFFS_MAX_ALIAS_LENGTH);
3339                 oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
3340                 break;
3341         }
3342
3343         /* process any xattrib modifications */
3344         if (xmod)
3345                 yaffs_apply_xattrib_mod(in, (char *)buffer, xmod);
3346
3347         /* Tags */
3348         memset(&new_tags, 0, sizeof(new_tags));
3349         in->serial++;
3350         new_tags.chunk_id = 0;
3351         new_tags.obj_id = in->obj_id;
3352         new_tags.serial_number = in->serial;
3353
3354         /* Add extra info for file header */
3355         new_tags.extra_available = 1;
3356         new_tags.extra_parent_id = oh->parent_obj_id;
3357         new_tags.extra_file_size = file_size;
3358         new_tags.extra_is_shrink = oh->is_shrink;
3359         new_tags.extra_equiv_id = oh->equiv_id;
3360         new_tags.extra_shadows = (oh->shadows_obj > 0) ? 1 : 0;
3361         new_tags.extra_obj_type = in->variant_type;
3362         yaffs_verify_oh(in, oh, &new_tags, 1);
3363
3364         /* Create new chunk in NAND */
3365         new_chunk_id =
3366             yaffs_write_new_chunk(dev, buffer, &new_tags,
3367                                   (prev_chunk_id > 0) ? 1 : 0);
3368
3369         if (buffer)
3370                 yaffs_release_temp_buffer(dev, buffer);
3371
3372         if (new_chunk_id < 0)
3373                 return new_chunk_id;
3374
3375         in->hdr_chunk = new_chunk_id;
3376
3377         if (prev_chunk_id > 0)
3378                 yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
3379
3380         if (!yaffs_obj_cache_dirty(in))
3381                 in->dirty = 0;
3382
3383         /* If this was a shrink, then mark the block
3384          * that the chunk lives on */
3385         if (is_shrink) {
3386                 bi = yaffs_get_block_info(in->my_dev,
3387                                           new_chunk_id /
3388                                           in->my_dev->param.chunks_per_block);
3389                 bi->has_shrink_hdr = 1;
3390         }
3391
3392
3393         return new_chunk_id;
3394 }
3395
3396 /*--------------------- File read/write ------------------------
3397  * Read and write have very similar structures.
3398  * In general the read/write has three parts to it
3399  * An incomplete chunk to start with (if the read/write is not chunk-aligned)
3400  * Some complete chunks
3401  * An incomplete chunk to end off with
3402  *
3403  * Curve-balls: the first chunk might also be the last chunk.
3404  */
3405
3406 int yaffs_file_rd(struct yaffs_obj *in, u8 * buffer, loff_t offset, int n_bytes)
3407 {
3408         int chunk;
3409         u32 start;
3410         int n_copy;
3411         int n = n_bytes;
3412         int n_done = 0;
3413         struct yaffs_cache *cache;
3414         struct yaffs_dev *dev;
3415
3416         dev = in->my_dev;
3417
3418         while (n > 0) {
3419                 yaffs_addr_to_chunk(dev, offset, &chunk, &start);
3420                 chunk++;
3421
3422                 /* OK now check for the curveball where the start and end are in
3423                  * the same chunk.
3424                  */
3425                 if ((start + n) < dev->data_bytes_per_chunk)
3426                         n_copy = n;
3427                 else
3428                         n_copy = dev->data_bytes_per_chunk - start;
3429
3430                 cache = yaffs_find_chunk_cache(in, chunk);
3431
3432                 /* If the chunk is already in the cache or it is less than
3433                  * a whole chunk or we're using inband tags then use the cache
3434                  * (if there is caching) else bypass the cache.