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