Remove unused WinCE Makefile
[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         /* Now find an object value that has not already been taken
1926          * by scanning the list.
1927          */
1928
1929         while (!found) {
1930                 found = 1;
1931                 n += YAFFS_NOBJECT_BUCKETS;
1932                 if (1 || dev->obj_bucket[bucket].count > 0) {
1933                         list_for_each(i, &dev->obj_bucket[bucket].list) {
1934                                 /* If there is already one in the list */
1935                                 if (i && list_entry(i, struct yaffs_obj,
1936                                                     hash_link)->obj_id == n) {
1937                                         found = 0;
1938                                 }
1939                         }
1940                 }
1941         }
1942         return n;
1943 }
1944
1945 static void yaffs_hash_obj(struct yaffs_obj *in)
1946 {
1947         int bucket = yaffs_hash_fn(in->obj_id);
1948         struct yaffs_dev *dev = in->my_dev;
1949
1950         list_add(&in->hash_link, &dev->obj_bucket[bucket].list);
1951         dev->obj_bucket[bucket].count++;
1952 }
1953
1954 struct yaffs_obj *yaffs_find_by_number(struct yaffs_dev *dev, u32 number)
1955 {
1956         int bucket = yaffs_hash_fn(number);
1957         struct list_head *i;
1958         struct yaffs_obj *in;
1959
1960         list_for_each(i, &dev->obj_bucket[bucket].list) {
1961                 /* Look if it is in the list */
1962                 in = list_entry(i, struct yaffs_obj, hash_link);
1963                 if (in->obj_id == number) {
1964                         /* Don't show if it is defered free */
1965                         if (in->defered_free)
1966                                 return NULL;
1967                         return in;
1968                 }
1969         }
1970
1971         return NULL;
1972 }
1973
1974 static struct yaffs_obj *yaffs_new_obj(struct yaffs_dev *dev, int number,
1975                                 enum yaffs_obj_type type)
1976 {
1977         struct yaffs_obj *the_obj = NULL;
1978         struct yaffs_tnode *tn = NULL;
1979
1980         if (number < 0)
1981                 number = yaffs_new_obj_id(dev);
1982
1983         if (type == YAFFS_OBJECT_TYPE_FILE) {
1984                 tn = yaffs_get_tnode(dev);
1985                 if (!tn)
1986                         return NULL;
1987         }
1988
1989         the_obj = yaffs_alloc_empty_obj(dev);
1990         if (!the_obj) {
1991                 if (tn)
1992                         yaffs_free_tnode(dev, tn);
1993                 return NULL;
1994         }
1995
1996         the_obj->fake = 0;
1997         the_obj->rename_allowed = 1;
1998         the_obj->unlink_allowed = 1;
1999         the_obj->obj_id = number;
2000         yaffs_hash_obj(the_obj);
2001         the_obj->variant_type = type;
2002         yaffs_load_current_time(the_obj, 1, 1);
2003
2004         switch (type) {
2005         case YAFFS_OBJECT_TYPE_FILE:
2006                 the_obj->variant.file_variant.file_size = 0;
2007                 the_obj->variant.file_variant.scanned_size = 0;
2008                 the_obj->variant.file_variant.shrink_size =
2009                                                 yaffs_max_file_size(dev);
2010                 the_obj->variant.file_variant.top_level = 0;
2011                 the_obj->variant.file_variant.top = tn;
2012                 break;
2013         case YAFFS_OBJECT_TYPE_DIRECTORY:
2014                 INIT_LIST_HEAD(&the_obj->variant.dir_variant.children);
2015                 INIT_LIST_HEAD(&the_obj->variant.dir_variant.dirty);
2016                 break;
2017         case YAFFS_OBJECT_TYPE_SYMLINK:
2018         case YAFFS_OBJECT_TYPE_HARDLINK:
2019         case YAFFS_OBJECT_TYPE_SPECIAL:
2020                 /* No action required */
2021                 break;
2022         case YAFFS_OBJECT_TYPE_UNKNOWN:
2023                 /* todo this should not happen */
2024                 break;
2025         }
2026         return the_obj;
2027 }
2028
2029 static struct yaffs_obj *yaffs_create_fake_dir(struct yaffs_dev *dev,
2030                                                int number, u32 mode)
2031 {
2032
2033         struct yaffs_obj *obj =
2034             yaffs_new_obj(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
2035
2036         if (!obj)
2037                 return NULL;
2038
2039         obj->fake = 1;  /* it is fake so it might not use NAND */
2040         obj->rename_allowed = 0;
2041         obj->unlink_allowed = 0;
2042         obj->deleted = 0;
2043         obj->unlinked = 0;
2044         obj->yst_mode = mode;
2045         obj->my_dev = dev;
2046         obj->hdr_chunk = 0;     /* Not a valid chunk. */
2047         return obj;
2048
2049 }
2050
2051
2052 static void yaffs_init_tnodes_and_objs(struct yaffs_dev *dev)
2053 {
2054         int i;
2055
2056         dev->n_obj = 0;
2057         dev->n_tnodes = 0;
2058         yaffs_init_raw_tnodes_and_objs(dev);
2059
2060         for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
2061                 INIT_LIST_HEAD(&dev->obj_bucket[i].list);
2062                 dev->obj_bucket[i].count = 0;
2063         }
2064 }
2065
2066 struct yaffs_obj *yaffs_find_or_create_by_number(struct yaffs_dev *dev,
2067                                                  int number,
2068                                                  enum yaffs_obj_type type)
2069 {
2070         struct yaffs_obj *the_obj = NULL;
2071
2072         if (number > 0)
2073                 the_obj = yaffs_find_by_number(dev, number);
2074
2075         if (!the_obj)
2076                 the_obj = yaffs_new_obj(dev, number, type);
2077
2078         return the_obj;
2079
2080 }
2081
2082 YCHAR *yaffs_clone_str(const YCHAR *str)
2083 {
2084         YCHAR *new_str = NULL;
2085         int len;
2086
2087         if (!str)
2088                 str = _Y("");
2089
2090         len = strnlen(str, YAFFS_MAX_ALIAS_LENGTH);
2091         new_str = kmalloc((len + 1) * sizeof(YCHAR), GFP_NOFS);
2092         if (new_str) {
2093                 strncpy(new_str, str, len);
2094                 new_str[len] = 0;
2095         }
2096         return new_str;
2097
2098 }
2099 /*
2100  *yaffs_update_parent() handles fixing a directories mtime and ctime when a new
2101  * link (ie. name) is created or deleted in the directory.
2102  *
2103  * ie.
2104  *   create dir/a : update dir's mtime/ctime
2105  *   rm dir/a:   update dir's mtime/ctime
2106  *   modify dir/a: don't update dir's mtimme/ctime
2107  *
2108  * This can be handled immediately or defered. Defering helps reduce the number
2109  * of updates when many files in a directory are changed within a brief period.
2110  *
2111  * If the directory updating is defered then yaffs_update_dirty_dirs must be
2112  * called periodically.
2113  */
2114
2115 static void yaffs_update_parent(struct yaffs_obj *obj)
2116 {
2117         struct yaffs_dev *dev;
2118
2119         if (!obj)
2120                 return;
2121         dev = obj->my_dev;
2122         obj->dirty = 1;
2123         yaffs_load_current_time(obj, 0, 1);
2124         if (dev->param.defered_dir_update) {
2125                 struct list_head *link = &obj->variant.dir_variant.dirty;
2126
2127                 if (list_empty(link)) {
2128                         list_add(link, &dev->dirty_dirs);
2129                         yaffs_trace(YAFFS_TRACE_BACKGROUND,
2130                           "Added object %d to dirty directories",
2131                            obj->obj_id);
2132                 }
2133
2134         } else {
2135                 yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
2136         }
2137 }
2138
2139 void yaffs_update_dirty_dirs(struct yaffs_dev *dev)
2140 {
2141         struct list_head *link;
2142         struct yaffs_obj *obj;
2143         struct yaffs_dir_var *d_s;
2144         union yaffs_obj_var *o_v;
2145
2146         yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update dirty directories");
2147
2148         while (!list_empty(&dev->dirty_dirs)) {
2149                 link = dev->dirty_dirs.next;
2150                 list_del_init(link);
2151
2152                 d_s = list_entry(link, struct yaffs_dir_var, dirty);
2153                 o_v = list_entry(d_s, union yaffs_obj_var, dir_variant);
2154                 obj = list_entry(o_v, struct yaffs_obj, variant);
2155
2156                 yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update directory %d",
2157                         obj->obj_id);
2158
2159                 if (obj->dirty)
2160                         yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
2161         }
2162 }
2163
2164 /*
2165  * Mknod (create) a new object.
2166  * equiv_obj only has meaning for a hard link;
2167  * alias_str only has meaning for a symlink.
2168  * rdev only has meaning for devices (a subset of special objects)
2169  */
2170
2171 static struct yaffs_obj *yaffs_create_obj(enum yaffs_obj_type type,
2172                                           struct yaffs_obj *parent,
2173                                           const YCHAR *name,
2174                                           u32 mode,
2175                                           u32 uid,
2176                                           u32 gid,
2177                                           struct yaffs_obj *equiv_obj,
2178                                           const YCHAR *alias_str, u32 rdev)
2179 {
2180         struct yaffs_obj *in;
2181         YCHAR *str = NULL;
2182         struct yaffs_dev *dev = parent->my_dev;
2183
2184         /* Check if the entry exists.
2185          * If it does then fail the call since we don't want a dup. */
2186         if (yaffs_find_by_name(parent, name))
2187                 return NULL;
2188
2189         if (type == YAFFS_OBJECT_TYPE_SYMLINK) {
2190                 str = yaffs_clone_str(alias_str);
2191                 if (!str)
2192                         return NULL;
2193         }
2194
2195         in = yaffs_new_obj(dev, -1, type);
2196
2197         if (!in) {
2198                 kfree(str);
2199                 return NULL;
2200         }
2201
2202         in->hdr_chunk = 0;
2203         in->valid = 1;
2204         in->variant_type = type;
2205
2206         in->yst_mode = mode;
2207
2208         yaffs_attribs_init(in, gid, uid, rdev);
2209
2210         in->n_data_chunks = 0;
2211
2212         yaffs_set_obj_name(in, name);
2213         in->dirty = 1;
2214
2215         yaffs_add_obj_to_dir(parent, in);
2216
2217         in->my_dev = parent->my_dev;
2218
2219         switch (type) {
2220         case YAFFS_OBJECT_TYPE_SYMLINK:
2221                 in->variant.symlink_variant.alias = str;
2222                 break;
2223         case YAFFS_OBJECT_TYPE_HARDLINK:
2224                 in->variant.hardlink_variant.equiv_obj = equiv_obj;
2225                 in->variant.hardlink_variant.equiv_id = equiv_obj->obj_id;
2226                 list_add(&in->hard_links, &equiv_obj->hard_links);
2227                 break;
2228         case YAFFS_OBJECT_TYPE_FILE:
2229         case YAFFS_OBJECT_TYPE_DIRECTORY:
2230         case YAFFS_OBJECT_TYPE_SPECIAL:
2231         case YAFFS_OBJECT_TYPE_UNKNOWN:
2232                 /* do nothing */
2233                 break;
2234         }
2235
2236         if (yaffs_update_oh(in, name, 0, 0, 0, NULL) < 0) {
2237                 /* Could not create the object header, fail */
2238                 yaffs_del_obj(in);
2239                 in = NULL;
2240         }
2241
2242         if (in)
2243                 yaffs_update_parent(parent);
2244
2245         return in;
2246 }
2247
2248 struct yaffs_obj *yaffs_create_file(struct yaffs_obj *parent,
2249                                     const YCHAR *name, u32 mode, u32 uid,
2250                                     u32 gid)
2251 {
2252         return yaffs_create_obj(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
2253                                 uid, gid, NULL, NULL, 0);
2254 }
2255
2256 struct yaffs_obj *yaffs_create_dir(struct yaffs_obj *parent, const YCHAR *name,
2257                                    u32 mode, u32 uid, u32 gid)
2258 {
2259         return yaffs_create_obj(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
2260                                 mode, uid, gid, NULL, NULL, 0);
2261 }
2262
2263 struct yaffs_obj *yaffs_create_special(struct yaffs_obj *parent,
2264                                        const YCHAR *name, u32 mode, u32 uid,
2265                                        u32 gid, u32 rdev)
2266 {
2267         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
2268                                 uid, gid, NULL, NULL, rdev);
2269 }
2270
2271 struct yaffs_obj *yaffs_create_symlink(struct yaffs_obj *parent,
2272                                        const YCHAR *name, u32 mode, u32 uid,
2273                                        u32 gid, const YCHAR *alias)
2274 {
2275         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
2276                                 uid, gid, NULL, alias, 0);
2277 }
2278
2279 /* yaffs_link_obj returns the object id of the equivalent object.*/
2280 struct yaffs_obj *yaffs_link_obj(struct yaffs_obj *parent, const YCHAR * name,
2281                                  struct yaffs_obj *equiv_obj)
2282 {
2283         /* Get the real object in case we were fed a hard link obj */
2284         equiv_obj = yaffs_get_equivalent_obj(equiv_obj);
2285
2286         if (yaffs_create_obj(YAFFS_OBJECT_TYPE_HARDLINK,
2287                         parent, name, 0, 0, 0,
2288                         equiv_obj, NULL, 0))
2289                 return equiv_obj;
2290
2291         return NULL;
2292
2293 }
2294
2295
2296
2297 /*---------------------- Block Management and Page Allocation -------------*/
2298
2299 static void yaffs_deinit_blocks(struct yaffs_dev *dev)
2300 {
2301         if (dev->block_info_alt && dev->block_info)
2302                 vfree(dev->block_info);
2303         else
2304                 kfree(dev->block_info);
2305
2306         dev->block_info_alt = 0;
2307
2308         dev->block_info = NULL;
2309
2310         if (dev->chunk_bits_alt && dev->chunk_bits)
2311                 vfree(dev->chunk_bits);
2312         else
2313                 kfree(dev->chunk_bits);
2314         dev->chunk_bits_alt = 0;
2315         dev->chunk_bits = NULL;
2316 }
2317
2318 static int yaffs_init_blocks(struct yaffs_dev *dev)
2319 {
2320         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
2321
2322         dev->block_info = NULL;
2323         dev->chunk_bits = NULL;
2324         dev->alloc_block = -1;  /* force it to get a new one */
2325
2326         /* If the first allocation strategy fails, thry the alternate one */
2327         dev->block_info =
2328                 kmalloc(n_blocks * sizeof(struct yaffs_block_info), GFP_NOFS);
2329         if (!dev->block_info) {
2330                 dev->block_info =
2331                     vmalloc(n_blocks * sizeof(struct yaffs_block_info));
2332                 dev->block_info_alt = 1;
2333         } else {
2334                 dev->block_info_alt = 0;
2335         }
2336
2337         if (!dev->block_info)
2338                 goto alloc_error;
2339
2340         /* Set up dynamic blockinfo stuff. Round up bytes. */
2341         dev->chunk_bit_stride = (dev->param.chunks_per_block + 7) / 8;
2342         dev->chunk_bits =
2343                 kmalloc(dev->chunk_bit_stride * n_blocks, GFP_NOFS);
2344         if (!dev->chunk_bits) {
2345                 dev->chunk_bits =
2346                     vmalloc(dev->chunk_bit_stride * n_blocks);
2347                 dev->chunk_bits_alt = 1;
2348         } else {
2349                 dev->chunk_bits_alt = 0;
2350         }
2351         if (!dev->chunk_bits)
2352                 goto alloc_error;
2353
2354
2355         memset(dev->block_info, 0, n_blocks * sizeof(struct yaffs_block_info));
2356         memset(dev->chunk_bits, 0, dev->chunk_bit_stride * n_blocks);
2357         return YAFFS_OK;
2358
2359 alloc_error:
2360         yaffs_deinit_blocks(dev);
2361         return YAFFS_FAIL;
2362 }
2363
2364
2365 void yaffs_block_became_dirty(struct yaffs_dev *dev, int block_no)
2366 {
2367         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block_no);
2368         int erased_ok = 0;
2369         int i;
2370
2371         /* If the block is still healthy erase it and mark as clean.
2372          * If the block has had a data failure, then retire it.
2373          */
2374
2375         yaffs_trace(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
2376                 "yaffs_block_became_dirty block %d state %d %s",
2377                 block_no, bi->block_state,
2378                 (bi->needs_retiring) ? "needs retiring" : "");
2379
2380         yaffs2_clear_oldest_dirty_seq(dev, bi);
2381
2382         bi->block_state = YAFFS_BLOCK_STATE_DIRTY;
2383
2384         /* If this is the block being garbage collected then stop gc'ing */
2385         if (block_no == dev->gc_block)
2386                 dev->gc_block = 0;
2387
2388         /* If this block is currently the best candidate for gc
2389          * then drop as a candidate */
2390         if (block_no == dev->gc_dirtiest) {
2391                 dev->gc_dirtiest = 0;
2392                 dev->gc_pages_in_use = 0;
2393         }
2394
2395         if (!bi->needs_retiring) {
2396                 yaffs2_checkpt_invalidate(dev);
2397                 erased_ok = yaffs_erase_block(dev, block_no);
2398                 if (!erased_ok) {
2399                         dev->n_erase_failures++;
2400                         yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
2401                           "**>> Erasure failed %d", block_no);
2402                 }
2403         }
2404
2405         /* Verify erasure if needed */
2406         if (erased_ok &&
2407             ((yaffs_trace_mask & YAFFS_TRACE_ERASE) ||
2408              !yaffs_skip_verification(dev))) {
2409                 for (i = 0; i < dev->param.chunks_per_block; i++) {
2410                         if (!yaffs_check_chunk_erased(dev,
2411                                 block_no * dev->param.chunks_per_block + i)) {
2412                                 yaffs_trace(YAFFS_TRACE_ERROR,
2413                                         ">>Block %d erasure supposedly OK, but chunk %d not erased",
2414                                         block_no, i);
2415                         }
2416                 }
2417         }
2418
2419         if (!erased_ok) {
2420                 /* We lost a block of free space */
2421                 dev->n_free_chunks -= dev->param.chunks_per_block;
2422                 yaffs_retire_block(dev, block_no);
2423                 yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
2424                         "**>> Block %d retired", block_no);
2425                 return;
2426         }
2427
2428         /* Clean it up... */
2429         bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
2430         bi->seq_number = 0;
2431         dev->n_erased_blocks++;
2432         bi->pages_in_use = 0;
2433         bi->soft_del_pages = 0;
2434         bi->has_shrink_hdr = 0;
2435         bi->skip_erased_check = 1;      /* Clean, so no need to check */
2436         bi->gc_prioritise = 0;
2437         bi->has_summary = 0;
2438
2439         yaffs_clear_chunk_bits(dev, block_no);
2440
2441         yaffs_trace(YAFFS_TRACE_ERASE, "Erased block %d", block_no);
2442 }
2443
2444 static inline int yaffs_gc_process_chunk(struct yaffs_dev *dev,
2445                                         struct yaffs_block_info *bi,
2446                                         int old_chunk, u8 *buffer)
2447 {
2448         int new_chunk;
2449         int mark_flash = 1;
2450         struct yaffs_ext_tags tags;
2451         struct yaffs_obj *object;
2452         int matching_chunk;
2453         int ret_val = YAFFS_OK;
2454
2455         memset(&tags, 0, sizeof(tags));
2456         yaffs_rd_chunk_tags_nand(dev, old_chunk,
2457                                  buffer, &tags);
2458         object = yaffs_find_by_number(dev, tags.obj_id);
2459
2460         yaffs_trace(YAFFS_TRACE_GC_DETAIL,
2461                 "Collecting chunk in block %d, %d %d %d ",
2462                 dev->gc_chunk, tags.obj_id,
2463                 tags.chunk_id, tags.n_bytes);
2464
2465         if (object && !yaffs_skip_verification(dev)) {
2466                 if (tags.chunk_id == 0)
2467                         matching_chunk =
2468                             object->hdr_chunk;
2469                 else if (object->soft_del)
2470                         /* Defeat the test */
2471                         matching_chunk = old_chunk;
2472                 else
2473                         matching_chunk =
2474                             yaffs_find_chunk_in_file
2475                             (object, tags.chunk_id,
2476                              NULL);
2477
2478                 if (old_chunk != matching_chunk)
2479                         yaffs_trace(YAFFS_TRACE_ERROR,
2480                                 "gc: page in gc mismatch: %d %d %d %d",
2481                                 old_chunk,
2482                                 matching_chunk,
2483                                 tags.obj_id,
2484                                 tags.chunk_id);
2485         }
2486
2487         if (!object) {
2488                 yaffs_trace(YAFFS_TRACE_ERROR,
2489                         "page %d in gc has no object: %d %d %d ",
2490                         old_chunk,
2491                         tags.obj_id, tags.chunk_id,
2492                         tags.n_bytes);
2493         }
2494
2495         if (object &&
2496             object->deleted &&
2497             object->soft_del && tags.chunk_id != 0) {
2498                 /* Data chunk in a soft deleted file,
2499                  * throw it away.
2500                  * It's a soft deleted data chunk,
2501                  * No need to copy this, just forget
2502                  * about it and fix up the object.
2503                  */
2504
2505                 /* Free chunks already includes
2506                  * softdeleted chunks, how ever this
2507                  * chunk is going to soon be really
2508                  * deleted which will increment free
2509                  * chunks. We have to decrement free
2510                  * chunks so this works out properly.
2511                  */
2512                 dev->n_free_chunks--;
2513                 bi->soft_del_pages--;
2514
2515                 object->n_data_chunks--;
2516                 if (object->n_data_chunks <= 0) {
2517                         /* remeber to clean up obj */
2518                         dev->gc_cleanup_list[dev->n_clean_ups] = tags.obj_id;
2519                         dev->n_clean_ups++;
2520                 }
2521                 mark_flash = 0;
2522         } else if (object) {
2523                 /* It's either a data chunk in a live
2524                  * file or an ObjectHeader, so we're
2525                  * interested in it.
2526                  * NB Need to keep the ObjectHeaders of
2527                  * deleted files until the whole file
2528                  * has been deleted off
2529                  */
2530                 tags.serial_number++;
2531                 dev->n_gc_copies++;
2532
2533                 if (tags.chunk_id == 0) {
2534                         /* It is an object Id,
2535                          * We need to nuke the
2536                          * shrinkheader flags since its
2537                          * work is done.
2538                          * Also need to clean up
2539                          * shadowing.
2540                          */
2541                         struct yaffs_obj_hdr *oh;
2542                         oh = (struct yaffs_obj_hdr *) buffer;
2543
2544                         oh->is_shrink = 0;
2545                         tags.extra_is_shrink = 0;
2546                         oh->shadows_obj = 0;
2547                         oh->inband_shadowed_obj_id = 0;
2548                         tags.extra_shadows = 0;
2549
2550                         /* Update file size */
2551                         if (object->variant_type == YAFFS_OBJECT_TYPE_FILE) {
2552                                 yaffs_oh_size_load(oh,
2553                                     object->variant.file_variant.file_size);
2554                                 tags.extra_file_size =
2555                                     object->variant.file_variant.file_size;
2556                         }
2557
2558                         yaffs_verify_oh(object, oh, &tags, 1);
2559                         new_chunk =
2560                             yaffs_write_new_chunk(dev, (u8 *) oh, &tags, 1);
2561                 } else {
2562                         new_chunk =
2563                             yaffs_write_new_chunk(dev, buffer, &tags, 1);
2564                 }
2565
2566                 if (new_chunk < 0) {
2567                         ret_val = YAFFS_FAIL;
2568                 } else {
2569
2570                         /* Now fix up the Tnodes etc. */
2571
2572                         if (tags.chunk_id == 0) {
2573                                 /* It's a header */
2574                                 object->hdr_chunk = new_chunk;
2575                                 object->serial = tags.serial_number;
2576                         } else {
2577                                 /* It's a data chunk */
2578                                 yaffs_put_chunk_in_file(object, tags.chunk_id,
2579                                                         new_chunk, 0);
2580                         }
2581                 }
2582         }
2583         if (ret_val == YAFFS_OK)
2584                 yaffs_chunk_del(dev, old_chunk, mark_flash, __LINE__);
2585         return ret_val;
2586 }
2587
2588 static int yaffs_gc_block(struct yaffs_dev *dev, int block, int whole_block)
2589 {
2590         int old_chunk;
2591         int ret_val = YAFFS_OK;
2592         int i;
2593         int is_checkpt_block;
2594         int max_copies;
2595         int chunks_before = yaffs_get_erased_chunks(dev);
2596         int chunks_after;
2597         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block);
2598
2599         is_checkpt_block = (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT);
2600
2601         yaffs_trace(YAFFS_TRACE_TRACING,
2602                 "Collecting block %d, in use %d, shrink %d, whole_block %d",
2603                 block, bi->pages_in_use, bi->has_shrink_hdr,
2604                 whole_block);
2605
2606         /*yaffs_verify_free_chunks(dev); */
2607
2608         if (bi->block_state == YAFFS_BLOCK_STATE_FULL)
2609                 bi->block_state = YAFFS_BLOCK_STATE_COLLECTING;
2610
2611         bi->has_shrink_hdr = 0; /* clear the flag so that the block can erase */
2612
2613         dev->gc_disable = 1;
2614
2615         yaffs_summary_gc(dev, block);
2616
2617         if (is_checkpt_block || !yaffs_still_some_chunks(dev, block)) {
2618                 yaffs_trace(YAFFS_TRACE_TRACING,
2619                         "Collecting block %d that has no chunks in use",
2620                         block);
2621                 yaffs_block_became_dirty(dev, block);
2622         } else {
2623
2624                 u8 *buffer = yaffs_get_temp_buffer(dev);
2625
2626                 yaffs_verify_blk(dev, bi, block);
2627
2628                 max_copies = (whole_block) ? dev->param.chunks_per_block : 5;
2629                 old_chunk = block * dev->param.chunks_per_block + dev->gc_chunk;
2630
2631                 for (/* init already done */ ;
2632                      ret_val == YAFFS_OK &&
2633                      dev->gc_chunk < dev->param.chunks_per_block &&
2634                      (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) &&
2635                      max_copies > 0;
2636                      dev->gc_chunk++, old_chunk++) {
2637                         if (yaffs_check_chunk_bit(dev, block, dev->gc_chunk)) {
2638                                 /* Page is in use and might need to be copied */
2639                                 max_copies--;
2640                                 ret_val = yaffs_gc_process_chunk(dev, bi,
2641                                                         old_chunk, buffer);
2642                         }
2643                 }
2644                 yaffs_release_temp_buffer(dev, buffer);
2645         }
2646
2647         yaffs_verify_collected_blk(dev, bi, block);
2648
2649         if (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
2650                 /*
2651                  * The gc did not complete. Set block state back to FULL
2652                  * because checkpointing does not restore gc.
2653                  */
2654                 bi->block_state = YAFFS_BLOCK_STATE_FULL;
2655         } else {
2656                 /* The gc completed. */
2657                 /* Do any required cleanups */
2658                 for (i = 0; i < dev->n_clean_ups; i++) {
2659                         /* Time to delete the file too */
2660                         struct yaffs_obj *object =
2661                             yaffs_find_by_number(dev, dev->gc_cleanup_list[i]);
2662                         if (object) {
2663                                 yaffs_free_tnode(dev,
2664                                           object->variant.file_variant.top);
2665                                 object->variant.file_variant.top = NULL;
2666                                 yaffs_trace(YAFFS_TRACE_GC,
2667                                         "yaffs: About to finally delete object %d",
2668                                         object->obj_id);
2669                                 yaffs_generic_obj_del(object);
2670                                 object->my_dev->n_deleted_files--;
2671                         }
2672
2673                 }
2674                 chunks_after = yaffs_get_erased_chunks(dev);
2675                 if (chunks_before >= chunks_after)
2676                         yaffs_trace(YAFFS_TRACE_GC,
2677                                 "gc did not increase free chunks before %d after %d",
2678                                 chunks_before, chunks_after);
2679                 dev->gc_block = 0;
2680                 dev->gc_chunk = 0;
2681                 dev->n_clean_ups = 0;
2682         }
2683
2684         dev->gc_disable = 0;
2685
2686         return ret_val;
2687 }
2688
2689 /*
2690  * find_gc_block() selects the dirtiest block (or close enough)
2691  * for garbage collection.
2692  */
2693
2694 static unsigned yaffs_find_gc_block(struct yaffs_dev *dev,
2695                                     int aggressive, int background)
2696 {
2697         int i;
2698         int iterations;
2699         unsigned selected = 0;
2700         int prioritised = 0;
2701         int prioritised_exist = 0;
2702         struct yaffs_block_info *bi;
2703         int threshold;
2704
2705         /* First let's see if we need to grab a prioritised block */
2706         if (dev->has_pending_prioritised_gc && !aggressive) {
2707                 dev->gc_dirtiest = 0;
2708                 bi = dev->block_info;
2709                 for (i = dev->internal_start_block;
2710                      i <= dev->internal_end_block && !selected; i++) {
2711
2712                         if (bi->gc_prioritise) {
2713                                 prioritised_exist = 1;
2714                                 if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2715                                     yaffs_block_ok_for_gc(dev, bi)) {
2716                                         selected = i;
2717                                         prioritised = 1;
2718                                 }
2719                         }
2720                         bi++;
2721                 }
2722
2723                 /*
2724                  * If there is a prioritised block and none was selected then
2725                  * this happened because there is at least one old dirty block
2726                  * gumming up the works. Let's gc the oldest dirty block.
2727                  */
2728
2729                 if (prioritised_exist &&
2730                     !selected && dev->oldest_dirty_block > 0)
2731                         selected = dev->oldest_dirty_block;
2732
2733                 if (!prioritised_exist) /* None found, so we can clear this */
2734                         dev->has_pending_prioritised_gc = 0;
2735         }
2736
2737         /* If we're doing aggressive GC then we are happy to take a less-dirty
2738          * block, and search harder.
2739          * else (leasurely gc), then we only bother to do this if the
2740          * block has only a few pages in use.
2741          */
2742
2743         if (!selected) {
2744                 int pages_used;
2745                 int n_blocks =
2746                     dev->internal_end_block - dev->internal_start_block + 1;
2747                 if (aggressive) {
2748                         threshold = dev->param.chunks_per_block;
2749                         iterations = n_blocks;
2750                 } else {
2751                         int max_threshold;
2752
2753                         if (background)
2754                                 max_threshold = dev->param.chunks_per_block / 2;
2755                         else
2756                                 max_threshold = dev->param.chunks_per_block / 8;
2757
2758                         if (max_threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2759                                 max_threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2760
2761                         threshold = background ? (dev->gc_not_done + 2) * 2 : 0;
2762                         if (threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2763                                 threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2764                         if (threshold > max_threshold)
2765                                 threshold = max_threshold;
2766
2767                         iterations = n_blocks / 16 + 1;
2768                         if (iterations > 100)
2769                                 iterations = 100;
2770                 }
2771
2772                 for (i = 0;
2773                      i < iterations &&
2774                      (dev->gc_dirtiest < 1 ||
2775                       dev->gc_pages_in_use > YAFFS_GC_GOOD_ENOUGH);
2776                      i++) {
2777                         dev->gc_block_finder++;
2778                         if (dev->gc_block_finder < dev->internal_start_block ||
2779                             dev->gc_block_finder > dev->internal_end_block)
2780                                 dev->gc_block_finder =
2781                                     dev->internal_start_block;
2782
2783                         bi = yaffs_get_block_info(dev, dev->gc_block_finder);
2784
2785                         pages_used = bi->pages_in_use - bi->soft_del_pages;
2786
2787                         if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2788                             pages_used < dev->param.chunks_per_block &&
2789                             (dev->gc_dirtiest < 1 ||
2790                              pages_used < dev->gc_pages_in_use) &&
2791                             yaffs_block_ok_for_gc(dev, bi)) {
2792                                 dev->gc_dirtiest = dev->gc_block_finder;
2793                                 dev->gc_pages_in_use = pages_used;
2794                         }
2795                 }
2796
2797                 if (dev->gc_dirtiest > 0 && dev->gc_pages_in_use <= threshold)
2798                         selected = dev->gc_dirtiest;
2799         }
2800
2801         /*
2802          * If nothing has been selected for a while, try the oldest dirty
2803          * because that's gumming up the works.
2804          */
2805
2806         if (!selected && dev->param.is_yaffs2 &&
2807             dev->gc_not_done >= (background ? 10 : 20)) {
2808                 yaffs2_find_oldest_dirty_seq(dev);
2809                 if (dev->oldest_dirty_block > 0) {
2810                         selected = dev->oldest_dirty_block;
2811                         dev->gc_dirtiest = selected;
2812                         dev->oldest_dirty_gc_count++;
2813                         bi = yaffs_get_block_info(dev, selected);
2814                         dev->gc_pages_in_use =
2815                             bi->pages_in_use - bi->soft_del_pages;
2816                 } else {
2817                         dev->gc_not_done = 0;
2818                 }
2819         }
2820
2821         if (selected) {
2822                 yaffs_trace(YAFFS_TRACE_GC,
2823                         "GC Selected block %d with %d free, prioritised:%d",
2824                         selected,
2825                         dev->param.chunks_per_block - dev->gc_pages_in_use,
2826                         prioritised);
2827
2828                 dev->n_gc_blocks++;
2829                 if (background)
2830                         dev->bg_gcs++;
2831
2832                 dev->gc_dirtiest = 0;
2833                 dev->gc_pages_in_use = 0;
2834                 dev->gc_not_done = 0;
2835                 if (dev->refresh_skip > 0)
2836                         dev->refresh_skip--;
2837         } else {
2838                 dev->gc_not_done++;
2839                 yaffs_trace(YAFFS_TRACE_GC,
2840                         "GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s",
2841                         dev->gc_block_finder, dev->gc_not_done, threshold,
2842                         dev->gc_dirtiest, dev->gc_pages_in_use,
2843                         dev->oldest_dirty_block, background ? " bg" : "");
2844         }
2845
2846         return selected;
2847 }
2848
2849 /* New garbage collector
2850  * If we're very low on erased blocks then we do aggressive garbage collection
2851  * otherwise we do "leasurely" garbage collection.
2852  * Aggressive gc looks further (whole array) and will accept less dirty blocks.
2853  * Passive gc only inspects smaller areas and only accepts more dirty blocks.
2854  *
2855  * The idea is to help clear out space in a more spread-out manner.
2856  * Dunno if it really does anything useful.
2857  */
2858 static int yaffs_check_gc(struct yaffs_dev *dev, int background)
2859 {
2860         int aggressive = 0;
2861         int gc_ok = YAFFS_OK;
2862         int max_tries = 0;
2863         int min_erased;
2864         int erased_chunks;
2865         int checkpt_block_adjust;
2866
2867         if (dev->param.gc_control_fn &&
2868                 (dev->param.gc_control_fn(dev) & 1) == 0)
2869                 return YAFFS_OK;
2870
2871         if (dev->gc_disable)
2872                 /* Bail out so we don't get recursive gc */
2873                 return YAFFS_OK;
2874
2875         /* This loop should pass the first time.
2876          * Only loops here if the collection does not increase space.
2877          */
2878
2879         do {
2880                 max_tries++;
2881
2882                 checkpt_block_adjust = yaffs_calc_checkpt_blocks_required(dev);
2883
2884                 min_erased =
2885                     dev->param.n_reserved_blocks + checkpt_block_adjust + 1;
2886                 erased_chunks =
2887                     dev->n_erased_blocks * dev->param.chunks_per_block;
2888
2889                 /* If we need a block soon then do aggressive gc. */
2890                 if (dev->n_erased_blocks < min_erased)
2891                         aggressive = 1;
2892                 else {
2893                         if (!background
2894                             && erased_chunks > (dev->n_free_chunks / 4))
2895                                 break;
2896
2897                         if (dev->gc_skip > 20)
2898                                 dev->gc_skip = 20;
2899                         if (erased_chunks < dev->n_free_chunks / 2 ||
2900                             dev->gc_skip < 1 || background)
2901                                 aggressive = 0;
2902                         else {
2903                                 dev->gc_skip--;
2904                                 break;
2905                         }
2906                 }
2907
2908                 dev->gc_skip = 5;
2909
2910                 /* If we don't already have a block being gc'd then see if we
2911                  * should start another */
2912
2913                 if (dev->gc_block < 1 && !aggressive) {
2914                         dev->gc_block = yaffs2_find_refresh_block(dev);
2915                         dev->gc_chunk = 0;
2916                         dev->n_clean_ups = 0;
2917                 }
2918                 if (dev->gc_block < 1) {
2919                         dev->gc_block =
2920                             yaffs_find_gc_block(dev, aggressive, background);
2921                         dev->gc_chunk = 0;
2922                         dev->n_clean_ups = 0;
2923                 }
2924
2925                 if (dev->gc_block > 0) {
2926                         dev->all_gcs++;
2927                         if (!aggressive)
2928                                 dev->passive_gc_count++;
2929
2930                         yaffs_trace(YAFFS_TRACE_GC,
2931                                 "yaffs: GC n_erased_blocks %d aggressive %d",
2932                                 dev->n_erased_blocks, aggressive);
2933
2934                         gc_ok = yaffs_gc_block(dev, dev->gc_block, aggressive);
2935                 }
2936
2937                 if (dev->n_erased_blocks < (dev->param.n_reserved_blocks) &&
2938                     dev->gc_block > 0) {
2939                         yaffs_trace(YAFFS_TRACE_GC,
2940                                 "yaffs: GC !!!no reclaim!!! n_erased_blocks %d after try %d block %d",
2941                                 dev->n_erased_blocks, max_tries,
2942                                 dev->gc_block);
2943                 }
2944         } while ((dev->n_erased_blocks < dev->param.n_reserved_blocks) &&
2945                  (dev->gc_block > 0) && (max_tries < 2));
2946
2947         return aggressive ? gc_ok : YAFFS_OK;
2948 }
2949
2950 /*
2951  * yaffs_bg_gc()
2952  * Garbage collects. Intended to be called from a background thread.
2953  * Returns non-zero if at least half the free chunks are erased.
2954  */
2955 int yaffs_bg_gc(struct yaffs_dev *dev, unsigned urgency)
2956 {
2957         int erased_chunks = dev->n_erased_blocks * dev->param.chunks_per_block;
2958
2959         yaffs_trace(YAFFS_TRACE_BACKGROUND, "Background gc %u", urgency);
2960
2961         yaffs_check_gc(dev, 1);
2962         return erased_chunks > dev->n_free_chunks / 2;
2963 }
2964
2965 /*-------------------- Data file manipulation -----------------*/
2966
2967 static int yaffs_rd_data_obj(struct yaffs_obj *in, int inode_chunk, u8 * buffer)
2968 {
2969         int nand_chunk = yaffs_find_chunk_in_file(in, inode_chunk, NULL);
2970
2971         if (nand_chunk >= 0)
2972                 return yaffs_rd_chunk_tags_nand(in->my_dev, nand_chunk,
2973                                                 buffer, NULL);
2974         else {
2975                 yaffs_trace(YAFFS_TRACE_NANDACCESS,
2976                         "Chunk %d not found zero instead",
2977                         nand_chunk);
2978                 /* get sane (zero) data if you read a hole */
2979                 memset(buffer, 0, in->my_dev->data_bytes_per_chunk);
2980                 return 0;
2981         }
2982
2983 }
2984
2985 void yaffs_chunk_del(struct yaffs_dev *dev, int chunk_id, int mark_flash,
2986                      int lyn)
2987 {
2988         int block;
2989         int page;
2990         struct yaffs_ext_tags tags;
2991         struct yaffs_block_info *bi;
2992
2993         if (chunk_id <= 0)
2994                 return;
2995
2996         dev->n_deletions++;
2997         block = chunk_id / dev->param.chunks_per_block;
2998         page = chunk_id % dev->param.chunks_per_block;
2999
3000         if (!yaffs_check_chunk_bit(dev, block, page))
3001                 yaffs_trace(YAFFS_TRACE_VERIFY,
3002                         "Deleting invalid chunk %d", chunk_id);
3003
3004         bi = yaffs_get_block_info(dev, block);
3005
3006         yaffs2_update_oldest_dirty_seq(dev, block, bi);
3007
3008         yaffs_trace(YAFFS_TRACE_DELETION,
3009                 "line %d delete of chunk %d",
3010                 lyn, chunk_id);
3011
3012         if (!dev->param.is_yaffs2 && mark_flash &&
3013             bi->block_state != YAFFS_BLOCK_STATE_COLLECTING) {
3014
3015                 memset(&tags, 0, sizeof(tags));
3016                 tags.is_deleted = 1;
3017                 yaffs_wr_chunk_tags_nand(dev, chunk_id, NULL, &tags);
3018                 yaffs_handle_chunk_update(dev, chunk_id, &tags);
3019         } else {
3020                 dev->n_unmarked_deletions++;
3021         }
3022
3023         /* Pull out of the management area.
3024          * If the whole block became dirty, this will kick off an erasure.
3025          */
3026         if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING ||
3027             bi->block_state == YAFFS_BLOCK_STATE_FULL ||
3028             bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
3029             bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
3030                 dev->n_free_chunks++;
3031                 yaffs_clear_chunk_bit(dev, block, page);
3032                 bi->pages_in_use--;
3033
3034                 if (bi->pages_in_use == 0 &&
3035                     !bi->has_shrink_hdr &&
3036                     bi->block_state != YAFFS_BLOCK_STATE_ALLOCATING &&
3037                     bi->block_state != YAFFS_BLOCK_STATE_NEEDS_SCAN) {
3038                         yaffs_block_became_dirty(dev, block);
3039                 }
3040         }
3041 }
3042
3043 static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
3044                              const u8 *buffer, int n_bytes, int use_reserve)
3045 {
3046         /* Find old chunk Need to do this to get serial number
3047          * Write new one and patch into tree.
3048          * Invalidate old tags.
3049          */
3050
3051         int prev_chunk_id;
3052         struct yaffs_ext_tags prev_tags;
3053         int new_chunk_id;
3054         struct yaffs_ext_tags new_tags;
3055         struct yaffs_dev *dev = in->my_dev;
3056
3057         yaffs_check_gc(dev, 0);
3058
3059         /* Get the previous chunk at this location in the file if it exists.
3060          * If it does not exist then put a zero into the tree. This creates
3061          * the tnode now, rather than later when it is harder to clean up.
3062          */
3063         prev_chunk_id = yaffs_find_chunk_in_file(in, inode_chunk, &prev_tags);
3064         if (prev_chunk_id < 1 &&
3065             !yaffs_put_chunk_in_file(in, inode_chunk, 0, 0))
3066                 return 0;
3067
3068         /* Set up new tags */
3069         memset(&new_tags, 0, sizeof(new_tags));
3070
3071         new_tags.chunk_id = inode_chunk;
3072         new_tags.obj_id = in->obj_id;
3073         new_tags.serial_number =
3074             (prev_chunk_id > 0) ? prev_tags.serial_number + 1 : 1;
3075         new_tags.n_bytes = n_bytes;
3076
3077         if (n_bytes < 1 || n_bytes > dev->param.total_bytes_per_chunk) {
3078                 yaffs_trace(YAFFS_TRACE_ERROR,
3079                   "Writing %d bytes to chunk!!!!!!!!!",
3080                    n_bytes);
3081                 BUG();
3082         }
3083
3084         new_chunk_id =
3085             yaffs_write_new_chunk(dev, buffer, &new_tags, use_reserve);
3086
3087         if (new_chunk_id > 0) {
3088                 yaffs_put_chunk_in_file(in, inode_chunk, new_chunk_id, 0);
3089
3090                 if (prev_chunk_id > 0)
3091                         yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
3092
3093                 yaffs_verify_file_sane(in);
3094         }
3095         return new_chunk_id;
3096
3097 }
3098
3099
3100
3101 static int yaffs_do_xattrib_mod(struct yaffs_obj *obj, int set,
3102                                 const YCHAR *name, const void *value, int size,
3103                                 int flags)
3104 {
3105         struct yaffs_xattr_mod xmod;
3106         int result;
3107
3108         xmod.set = set;
3109         xmod.name = name;
3110         xmod.data = value;
3111         xmod.size = size;
3112         xmod.flags = flags;
3113         xmod.result = -ENOSPC;
3114
3115         result = yaffs_update_oh(obj, NULL, 0, 0, 0, &xmod);
3116
3117         if (result > 0)
3118                 return xmod.result;
3119         else
3120                 return -ENOSPC;
3121 }
3122
3123 static int yaffs_apply_xattrib_mod(struct yaffs_obj *obj, char *buffer,
3124                                    struct yaffs_xattr_mod *xmod)
3125 {
3126         int retval = 0;
3127         int x_offs = sizeof(struct yaffs_obj_hdr);
3128         struct yaffs_dev *dev = obj->my_dev;
3129         int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
3130         char *x_buffer = buffer + x_offs;
3131
3132         if (xmod->set)
3133                 retval =
3134                     nval_set(x_buffer, x_size, xmod->name, xmod->data,
3135                              xmod->size, xmod->flags);
3136         else
3137                 retval = nval_del(x_buffer, x_size, xmod->name);
3138
3139         obj->has_xattr = nval_hasvalues(x_buffer, x_size);
3140         obj->xattr_known = 1;
3141         xmod->result = retval;
3142
3143         return retval;
3144 }
3145
3146 static int yaffs_do_xattrib_fetch(struct yaffs_obj *obj, const YCHAR *name,
3147                                   void *value, int size)
3148 {
3149         char *buffer = NULL;
3150         int result;
3151         struct yaffs_ext_tags tags;
3152         struct yaffs_dev *dev = obj->my_dev;
3153         int x_offs = sizeof(struct yaffs_obj_hdr);
3154         int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
3155         char *x_buffer;
3156         int retval = 0;
3157
3158         if (obj->hdr_chunk < 1)
3159                 return -ENODATA;
3160
3161         /* If we know that the object has no xattribs then don't do all the
3162          * reading and parsing.
3163          */
3164         if (obj->xattr_known && !obj->has_xattr) {
3165                 if (name)
3166                         return -ENODATA;
3167                 else
3168                         return 0;
3169         }
3170
3171         buffer = (char *)yaffs_get_temp_buffer(dev);
3172         if (!buffer)
3173                 return -ENOMEM;
3174
3175         result =
3176             yaffs_rd_chunk_tags_nand(dev, obj->hdr_chunk, (u8 *) buffer, &tags);
3177
3178         if (result != YAFFS_OK)
3179                 retval = -ENOENT;
3180         else {
3181                 x_buffer = buffer + x_offs;
3182
3183                 if (!obj->xattr_known) {
3184                         obj->has_xattr = nval_hasvalues(x_buffer, x_size);
3185                         obj->xattr_known = 1;
3186                 }
3187
3188                 if (name)
3189                         retval = nval_get(x_buffer, x_size, name, value, size);
3190                 else
3191                         retval = nval_list(x_buffer, x_size, value, size);
3192         }
3193         yaffs_release_temp_buffer(dev, (u8 *) buffer);
3194         return retval;
3195 }
3196
3197 int yaffs_set_xattrib(struct yaffs_obj *obj, const YCHAR * name,
3198                       const void *value, int size, int flags)
3199 {
3200         return yaffs_do_xattrib_mod(obj, 1, name, value, size, flags);
3201 }
3202
3203 int yaffs_remove_xattrib(struct yaffs_obj *obj, const YCHAR * name)
3204 {
3205         return yaffs_do_xattrib_mod(obj, 0, name, NULL, 0, 0);
3206 }
3207
3208 int yaffs_get_xattrib(struct yaffs_obj *obj, const YCHAR * name, void *value,
3209                       int size)
3210 {
3211         return yaffs_do_xattrib_fetch(obj, name, value, size);
3212 }
3213
3214 int yaffs_list_xattrib(struct yaffs_obj *obj, char *buffer, int size)
3215 {
3216         return yaffs_do_xattrib_fetch(obj, NULL, buffer, size);
3217 }
3218
3219 static void yaffs_check_obj_details_loaded(struct yaffs_obj *in)
3220 {
3221         u8 *buf;
3222         struct yaffs_obj_hdr *oh;
3223         struct yaffs_dev *dev;
3224         struct yaffs_ext_tags tags;
3225         int result;
3226         int alloc_failed = 0;
3227
3228         if (!in || !in->lazy_loaded || in->hdr_chunk < 1)
3229                 return;
3230
3231         dev = in->my_dev;
3232         in->lazy_loaded = 0;
3233         buf = yaffs_get_temp_buffer(dev);
3234
3235         result = yaffs_rd_chunk_tags_nand(dev, in->hdr_chunk, buf, &tags);
3236         oh = (struct yaffs_obj_hdr *)buf;
3237
3238         in->yst_mode = oh->yst_mode;
3239         yaffs_load_attribs(in, oh);
3240         yaffs_set_obj_name_from_oh(in, oh);
3241
3242         if (in->variant_type == YAFFS_OBJECT_TYPE_SYMLINK) {
3243                 in->variant.symlink_variant.alias =
3244                     yaffs_clone_str(oh->alias);
3245                 if (!in->variant.symlink_variant.alias)
3246                         alloc_failed = 1;       /* Not returned */
3247         }
3248         yaffs_release_temp_buffer(dev, buf);
3249 }
3250
3251 /* UpdateObjectHeader updates the header on NAND for an object.
3252  * If name is not NULL, then that new name is used.
3253  */
3254 int yaffs_update_oh(struct yaffs_obj *in, const YCHAR *name, int force,
3255                     int is_shrink, int shadows, struct yaffs_xattr_mod *xmod)
3256 {
3257
3258         struct yaffs_block_info *bi;
3259         struct yaffs_dev *dev = in->my_dev;
3260         int prev_chunk_id;
3261         int ret_val = 0;
3262         int result = 0;
3263         int new_chunk_id;
3264         struct yaffs_ext_tags new_tags;
3265         struct yaffs_ext_tags old_tags;
3266         const YCHAR *alias = NULL;
3267         u8 *buffer = NULL;
3268         YCHAR old_name[YAFFS_MAX_NAME_LENGTH + 1];
3269         struct yaffs_obj_hdr *oh = NULL;
3270         loff_t file_size = 0;
3271
3272         strcpy(old_name, _Y("silly old name"));
3273
3274         if (in->fake && in != dev->root_dir && !force && !xmod)
3275                 return ret_val;
3276
3277         yaffs_check_gc(dev, 0);
3278         yaffs_check_obj_details_loaded(in);
3279
3280         buffer = yaffs_get_temp_buffer(in->my_dev);
3281         oh = (struct yaffs_obj_hdr *)buffer;
3282
3283         prev_chunk_id = in->hdr_chunk;
3284
3285         if (prev_chunk_id > 0) {
3286                 result = yaffs_rd_chunk_tags_nand(dev, prev_chunk_id,
3287                                                   buffer, &old_tags);
3288
3289                 yaffs_verify_oh(in, oh, &old_tags, 0);
3290                 memcpy(old_name, oh->name, sizeof(oh->name));
3291                 memset(buffer, 0xff, sizeof(struct yaffs_obj_hdr));
3292         } else {
3293                 memset(buffer, 0xff, dev->data_bytes_per_chunk);
3294         }
3295
3296         oh->type = in->variant_type;
3297         oh->yst_mode = in->yst_mode;
3298         oh->shadows_obj = oh->inband_shadowed_obj_id = shadows;
3299
3300         yaffs_load_attribs_oh(oh, in);
3301
3302         if (in->parent)
3303                 oh->parent_obj_id = in->parent->obj_id;
3304         else
3305                 oh->parent_obj_id = 0;
3306
3307         if (name && *name) {
3308                 memset(oh->name, 0, sizeof(oh->name));
3309                 yaffs_load_oh_from_name(dev, oh->name, name);
3310         } else if (prev_chunk_id > 0) {
3311                 memcpy(oh->name, old_name, sizeof(oh->name));
3312         } else {
3313                 memset(oh->name, 0, sizeof(oh->name));
3314         }
3315
3316         oh->is_shrink = is_shrink;
3317
3318         switch (in->variant_type) {
3319         case YAFFS_OBJECT_TYPE_UNKNOWN:
3320                 /* Should not happen */
3321                 break;
3322         case YAFFS_OBJECT_TYPE_FILE:
3323                 if (oh->parent_obj_id != YAFFS_OBJECTID_DELETED &&
3324                     oh->parent_obj_id != YAFFS_OBJECTID_UNLINKED)
3325                         file_size = in->variant.file_variant.file_size;
3326                 yaffs_oh_size_load(oh, file_size);
3327                 break;
3328         case YAFFS_OBJECT_TYPE_HARDLINK:
3329                 oh->equiv_id = in->variant.hardlink_variant.equiv_id;
3330                 break;
3331         case YAFFS_OBJECT_TYPE_SPECIAL:
3332                 /* Do nothing */
3333                 break;
3334         case YAFFS_OBJECT_TYPE_DIRECTORY:
3335                 /* Do nothing */
3336                 break;
3337         case YAFFS_OBJECT_TYPE_SYMLINK:
3338                 alias = in->variant.symlink_variant.alias;
3339                 if (!alias)
3340                         alias = _Y("no alias");
3341                 strncpy(oh->alias, alias, YAFFS_MAX_ALIAS_LENGTH);
3342                 oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
3343                 break;
3344         }
3345
3346         /* process any xattrib modifications */
3347         if (xmod)
3348                 yaffs_apply_xattrib_mod(in, (char *)buffer, xmod);
3349
3350         /* Tags */
3351         memset(&new_tags, 0, sizeof(new_tags));
3352         in->serial++;
3353         new_tags.chunk_id = 0;
3354         new_tags.obj_id = in->obj_id;
3355         new_tags.serial_number = in->serial;
3356
3357         /* Add extra info for file header */
3358         new_tags.extra_available = 1;
3359         new_tags.extra_parent_id = oh->parent_obj_id;
3360         new_tags.extra_file_size = file_size;
3361         new_tags.extra_is_shrink = oh->is_shrink;
3362         new_tags.extra_equiv_id = oh->equiv_id;
3363         new_tags.extra_shadows = (oh->shadows_obj > 0) ? 1 : 0;
3364         new_tags.extra_obj_type = in->variant_type;
3365         yaffs_verify_oh(in, oh, &new_tags, 1);
3366
3367         /* Create new chunk in NAND */
3368         new_chunk_id =
3369             yaffs_write_new_chunk(dev, buffer, &new_tags,
3370                                   (prev_chunk_id > 0) ? 1 : 0);
3371
3372         if (buffer)
3373                 yaffs_release_temp_buffer(dev, buffer);
3374
3375         if (new_chunk_id < 0)
3376                 return new_chunk_id;
3377
3378         in->hdr_chunk = new_chunk_id;
3379
3380         if (prev_chunk_id > 0)
3381                 yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
3382
3383         if (!yaffs_obj_cache_dirty(in))
3384                 in->dirty = 0;
3385
3386         /* If this was a shrink, then mark the block
3387          * that the chunk lives on */
3388         if (is_shrink) {
3389                 bi = yaffs_get_block_info(in->my_dev,
3390                                           new_chunk_id /
3391                                           in->my_dev->param.chunks_per_block);
3392                 bi->has_shrink_hdr = 1;
3393         }
3394
3395
3396         return new_chunk_id;
3397 }
3398
3399 /*--------------------- File read/write ------------------------
3400  * Read and write have very similar structures.
3401  * In general the read/write has three parts to it
3402  * An incomplete chunk to start with (if the read/write is not chunk-aligned)
3403  * Some complete chunks
3404  * An incomplete chunk to end off with
3405  *
3406  * Curve-balls: the first chunk might also be the last chunk.
3407  */
3408
3409 int yaffs_file_rd(struct yaffs_obj *in, u8 * buffer, loff_t offset, int n_bytes)
3410 {
3411         int chunk;
3412         u32 start;
3413         int n_copy;
3414         int n = n_bytes;
3415         int n_done = 0;
3416         struct yaffs_cache *cache;
3417         struct yaffs_dev *dev;
3418
3419         dev = in->my_dev;
3420
3421         while (n > 0) {
3422                 yaffs_addr_to_chunk(dev, offset, &chunk, &start);
3423                 chunk++;
3424
3425                 /* OK now check for the curveball where the start and end are in
3426                  * the same chunk.
3427                  */
3428                 if ((start + n) < dev->data_bytes_per_chunk)
3429                         n_copy = n;
3430                 else
3431                         n_copy = dev->data_bytes_per_chunk - start;
3432
3433                 cache = yaffs_find_chunk_cache(in, chunk);
3434
3435 &nbs