24126a140abfbe225678f3a907d89b6b684ea7a9
[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 static inline 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_retired_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 #ifndef CONFIG_YAFFS_NO_SHORT_NAMES
676         memset(obj->short_name, 0, sizeof(obj->short_name));
677         if (name &&
678                 strnlen(name, YAFFS_SHORT_NAME_LENGTH + 1) <=
679                 YAFFS_SHORT_NAME_LENGTH)
680                 strcpy(obj->short_name, name);
681         else
682                 obj->short_name[0] = _Y('\0');
683 #endif
684         obj->sum = yaffs_calc_name_sum(name);
685 }
686
687 void yaffs_set_obj_name_from_oh(struct yaffs_obj *obj,
688                                 const struct yaffs_obj_hdr *oh)
689 {
690 #ifdef CONFIG_YAFFS_AUTO_UNICODE
691         YCHAR tmp_name[YAFFS_MAX_NAME_LENGTH + 1];
692         memset(tmp_name, 0, sizeof(tmp_name));
693         yaffs_load_name_from_oh(obj->my_dev, tmp_name, oh->name,
694                                 YAFFS_MAX_NAME_LENGTH + 1);
695         yaffs_set_obj_name(obj, tmp_name);
696 #else
697         yaffs_set_obj_name(obj, oh->name);
698 #endif
699 }
700
701 /*-------------------- TNODES -------------------
702
703  * List of spare tnodes
704  * The list is hooked together using the first pointer
705  * in the tnode.
706  */
707
708 struct yaffs_tnode *yaffs_get_tnode(struct yaffs_dev *dev)
709 {
710         struct yaffs_tnode *tn = yaffs_alloc_raw_tnode(dev);
711
712         if (tn) {
713                 memset(tn, 0, dev->tnode_size);
714                 dev->n_tnodes++;
715         }
716
717         dev->checkpoint_blocks_required = 0;    /* force recalculation */
718
719         return tn;
720 }
721
722 /* FreeTnode frees up a tnode and puts it back on the free list */
723 static void yaffs_free_tnode(struct yaffs_dev *dev, struct yaffs_tnode *tn)
724 {
725         yaffs_free_raw_tnode(dev, tn);
726         dev->n_tnodes--;
727         dev->checkpoint_blocks_required = 0;    /* force recalculation */
728 }
729
730 static void yaffs_deinit_tnodes_and_objs(struct yaffs_dev *dev)
731 {
732         yaffs_deinit_raw_tnodes_and_objs(dev);
733         dev->n_obj = 0;
734         dev->n_tnodes = 0;
735 }
736
737 void yaffs_load_tnode_0(struct yaffs_dev *dev, struct yaffs_tnode *tn,
738                         unsigned pos, unsigned val)
739 {
740         u32 *map = (u32 *) tn;
741         u32 bit_in_map;
742         u32 bit_in_word;
743         u32 word_in_map;
744         u32 mask;
745
746         pos &= YAFFS_TNODES_LEVEL0_MASK;
747         val >>= dev->chunk_grp_bits;
748
749         bit_in_map = pos * dev->tnode_width;
750         word_in_map = bit_in_map / 32;
751         bit_in_word = bit_in_map & (32 - 1);
752
753         mask = dev->tnode_mask << bit_in_word;
754
755         map[word_in_map] &= ~mask;
756         map[word_in_map] |= (mask & (val << bit_in_word));
757
758         if (dev->tnode_width > (32 - bit_in_word)) {
759                 bit_in_word = (32 - bit_in_word);
760                 word_in_map++;
761                 mask =
762                     dev->tnode_mask >> bit_in_word;
763                 map[word_in_map] &= ~mask;
764                 map[word_in_map] |= (mask & (val >> bit_in_word));
765         }
766 }
767
768 u32 yaffs_get_group_base(struct yaffs_dev *dev, struct yaffs_tnode *tn,
769                          unsigned pos)
770 {
771         u32 *map = (u32 *) tn;
772         u32 bit_in_map;
773         u32 bit_in_word;
774         u32 word_in_map;
775         u32 val;
776
777         pos &= YAFFS_TNODES_LEVEL0_MASK;
778
779         bit_in_map = pos * dev->tnode_width;
780         word_in_map = bit_in_map / 32;
781         bit_in_word = bit_in_map & (32 - 1);
782
783         val = map[word_in_map] >> bit_in_word;
784
785         if (dev->tnode_width > (32 - bit_in_word)) {
786                 bit_in_word = (32 - bit_in_word);
787                 word_in_map++;
788                 val |= (map[word_in_map] << bit_in_word);
789         }
790
791         val &= dev->tnode_mask;
792         val <<= dev->chunk_grp_bits;
793
794         return val;
795 }
796
797 /* ------------------- End of individual tnode manipulation -----------------*/
798
799 /* ---------Functions to manipulate the look-up tree (made up of tnodes) ------
800  * The look up tree is represented by the top tnode and the number of top_level
801  * in the tree. 0 means only the level 0 tnode is in the tree.
802  */
803
804 /* FindLevel0Tnode finds the level 0 tnode, if one exists. */
805 struct yaffs_tnode *yaffs_find_tnode_0(struct yaffs_dev *dev,
806                                        struct yaffs_file_var *file_struct,
807                                        u32 chunk_id)
808 {
809         struct yaffs_tnode *tn = file_struct->top;
810         u32 i;
811         int required_depth;
812         int level = file_struct->top_level;
813
814         dev = dev;
815
816         /* Check sane level and chunk Id */
817         if (level < 0 || level > YAFFS_TNODES_MAX_LEVEL)
818                 return NULL;
819
820         if (chunk_id > YAFFS_MAX_CHUNK_ID)
821                 return NULL;
822
823         /* First check we're tall enough (ie enough top_level) */
824
825         i = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
826         required_depth = 0;
827         while (i) {
828                 i >>= YAFFS_TNODES_INTERNAL_BITS;
829                 required_depth++;
830         }
831
832         if (required_depth > file_struct->top_level)
833                 return NULL;    /* Not tall enough, so we can't find it */
834
835         /* Traverse down to level 0 */
836         while (level > 0 && tn) {
837                 tn = tn->internal[(chunk_id >>
838                                    (YAFFS_TNODES_LEVEL0_BITS +
839                                     (level - 1) *
840                                     YAFFS_TNODES_INTERNAL_BITS)) &
841                                   YAFFS_TNODES_INTERNAL_MASK];
842                 level--;
843         }
844
845         return tn;
846 }
847
848 /* add_find_tnode_0 finds the level 0 tnode if it exists,
849  * otherwise first expands the tree.
850  * This happens in two steps:
851  *  1. If the tree isn't tall enough, then make it taller.
852  *  2. Scan down the tree towards the level 0 tnode adding tnodes if required.
853  *
854  * Used when modifying the tree.
855  *
856  *  If the tn argument is NULL, then a fresh tnode will be added otherwise the
857  *  specified tn will be plugged into the ttree.
858  */
859
860 struct yaffs_tnode *yaffs_add_find_tnode_0(struct yaffs_dev *dev,
861                                            struct yaffs_file_var *file_struct,
862                                            u32 chunk_id,
863                                            struct yaffs_tnode *passed_tn)
864 {
865         int required_depth;
866         int i;
867         int l;
868         struct yaffs_tnode *tn;
869         u32 x;
870
871         /* Check sane level and page Id */
872         if (file_struct->top_level < 0 ||
873             file_struct->top_level > YAFFS_TNODES_MAX_LEVEL)
874                 return NULL;
875
876         if (chunk_id > YAFFS_MAX_CHUNK_ID)
877                 return NULL;
878
879         /* First check we're tall enough (ie enough top_level) */
880
881         x = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
882         required_depth = 0;
883         while (x) {
884                 x >>= YAFFS_TNODES_INTERNAL_BITS;
885                 required_depth++;
886         }
887
888         if (required_depth > file_struct->top_level) {
889                 /* Not tall enough, gotta make the tree taller */
890                 for (i = file_struct->top_level; i < required_depth; i++) {
891
892                         tn = yaffs_get_tnode(dev);
893
894                         if (tn) {
895                                 tn->internal[0] = file_struct->top;
896                                 file_struct->top = tn;
897                                 file_struct->top_level++;
898                         } else {
899                                 yaffs_trace(YAFFS_TRACE_ERROR,
900                                         "yaffs: no more tnodes");
901                                 return NULL;
902                         }
903                 }
904         }
905
906         /* Traverse down to level 0, adding anything we need */
907
908         l = file_struct->top_level;
909         tn = file_struct->top;
910
911         if (l > 0) {
912                 while (l > 0 && tn) {
913                         x = (chunk_id >>
914                              (YAFFS_TNODES_LEVEL0_BITS +
915                               (l - 1) * YAFFS_TNODES_INTERNAL_BITS)) &
916                             YAFFS_TNODES_INTERNAL_MASK;
917
918                         if ((l > 1) && !tn->internal[x]) {
919                                 /* Add missing non-level-zero tnode */
920                                 tn->internal[x] = yaffs_get_tnode(dev);
921                                 if (!tn->internal[x])
922                                         return NULL;
923                         } else if (l == 1) {
924                                 /* Looking from level 1 at level 0 */
925                                 if (passed_tn) {
926                                         /* If we already have one, release it */
927                                         if (tn->internal[x])
928                                                 yaffs_free_tnode(dev,
929                                                         tn->internal[x]);
930                                         tn->internal[x] = passed_tn;
931
932                                 } else if (!tn->internal[x]) {
933                                         /* Don't have one, none passed in */
934                                         tn->internal[x] = yaffs_get_tnode(dev);
935                                         if (!tn->internal[x])
936                                                 return NULL;
937                                 }
938                         }
939
940                         tn = tn->internal[x];
941                         l--;
942                 }
943         } else {
944                 /* top is level 0 */
945                 if (passed_tn) {
946                         memcpy(tn, passed_tn,
947                                (dev->tnode_width * YAFFS_NTNODES_LEVEL0) / 8);
948                         yaffs_free_tnode(dev, passed_tn);
949                 }
950         }
951
952         return tn;
953 }
954
955 static int yaffs_tags_match(const struct yaffs_ext_tags *tags, int obj_id,
956                             int chunk_obj)
957 {
958         return (tags->chunk_id == chunk_obj &&
959                 tags->obj_id == obj_id &&
960                 !tags->is_deleted) ? 1 : 0;
961
962 }
963
964 static int yaffs_find_chunk_in_group(struct yaffs_dev *dev, int the_chunk,
965                                         struct yaffs_ext_tags *tags, int obj_id,
966                                         int inode_chunk)
967 {
968         int j;
969
970         for (j = 0; the_chunk && j < dev->chunk_grp_size; j++) {
971                 if (yaffs_check_chunk_bit
972                     (dev, the_chunk / dev->param.chunks_per_block,
973                      the_chunk % dev->param.chunks_per_block)) {
974
975                         if (dev->chunk_grp_size == 1)
976                                 return the_chunk;
977                         else {
978                                 yaffs_rd_chunk_tags_nand(dev, the_chunk, NULL,
979                                                          tags);
980                                 if (yaffs_tags_match(tags,
981                                                         obj_id, inode_chunk)) {
982                                         /* found it; */
983                                         return the_chunk;
984                                 }
985                         }
986                 }
987                 the_chunk++;
988         }
989         return -1;
990 }
991
992 static int yaffs_find_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
993                                     struct yaffs_ext_tags *tags)
994 {
995         /*Get the Tnode, then get the level 0 offset chunk offset */
996         struct yaffs_tnode *tn;
997         int the_chunk = -1;
998         struct yaffs_ext_tags local_tags;
999         int ret_val = -1;
1000         struct yaffs_dev *dev = in->my_dev;
1001
1002         if (!tags) {
1003                 /* Passed a NULL, so use our own tags space */
1004                 tags = &local_tags;
1005         }
1006
1007         tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
1008
1009         if (!tn)
1010                 return ret_val;
1011
1012         the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);
1013
1014         ret_val = yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
1015                                               inode_chunk);
1016         return ret_val;
1017 }
1018
1019 static int yaffs_find_del_file_chunk(struct yaffs_obj *in, int inode_chunk,
1020                                      struct yaffs_ext_tags *tags)
1021 {
1022         /* Get the Tnode, then get the level 0 offset chunk offset */
1023         struct yaffs_tnode *tn;
1024         int the_chunk = -1;
1025         struct yaffs_ext_tags local_tags;
1026         struct yaffs_dev *dev = in->my_dev;
1027         int ret_val = -1;
1028
1029         if (!tags) {
1030                 /* Passed a NULL, so use our own tags space */
1031                 tags = &local_tags;
1032         }
1033
1034         tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
1035
1036         if (!tn)
1037                 return ret_val;
1038
1039         the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);
1040
1041         ret_val = yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
1042                                               inode_chunk);
1043
1044         /* Delete the entry in the filestructure (if found) */
1045         if (ret_val != -1)
1046                 yaffs_load_tnode_0(dev, tn, inode_chunk, 0);
1047
1048         return ret_val;
1049 }
1050
1051 int yaffs_put_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
1052                             int nand_chunk, int in_scan)
1053 {
1054         /* NB in_scan is zero unless scanning.
1055          * For forward scanning, in_scan is > 0;
1056          * for backward scanning in_scan is < 0
1057          *
1058          * nand_chunk = 0 is a dummy insert to make sure the tnodes are there.
1059          */
1060
1061         struct yaffs_tnode *tn;
1062         struct yaffs_dev *dev = in->my_dev;
1063         int existing_cunk;
1064         struct yaffs_ext_tags existing_tags;
1065         struct yaffs_ext_tags new_tags;
1066         unsigned existing_serial, new_serial;
1067
1068         if (in->variant_type != YAFFS_OBJECT_TYPE_FILE) {
1069                 /* Just ignore an attempt at putting a chunk into a non-file
1070                  * during scanning.
1071                  * If it is not during Scanning then something went wrong!
1072                  */
1073                 if (!in_scan) {
1074                         yaffs_trace(YAFFS_TRACE_ERROR,
1075                                 "yaffs tragedy:attempt to put data chunk into a non-file"
1076                                 );
1077                         BUG();
1078                 }
1079
1080                 yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
1081                 return YAFFS_OK;
1082         }
1083
1084         tn = yaffs_add_find_tnode_0(dev,
1085                                     &in->variant.file_variant,
1086                                     inode_chunk, NULL);
1087         if (!tn)
1088                 return YAFFS_FAIL;
1089
1090         if (!nand_chunk)
1091                 /* Dummy insert, bail now */
1092                 return YAFFS_OK;
1093
1094         existing_cunk = yaffs_get_group_base(dev, tn, inode_chunk);
1095
1096         if (in_scan != 0) {
1097                 /* If we're scanning then we need to test for duplicates
1098                  * NB This does not need to be efficient since it should only
1099                  * happen when the power fails during a write, then only one
1100                  * chunk should ever be affected.
1101                  *
1102                  * Correction for YAFFS2: This could happen quite a lot and we
1103                  * need to think about efficiency! TODO
1104                  * Update: For backward scanning we don't need to re-read tags
1105                  * so this is quite cheap.
1106                  */
1107
1108                 if (existing_cunk > 0) {
1109                         /* NB Right now existing chunk will not be real
1110                          * chunk_id if the chunk group size > 1
1111                          * thus we have to do a FindChunkInFile to get the
1112                          * real chunk id.
1113                          *
1114                          * We have a duplicate now we need to decide which
1115                          * one to use:
1116                          *
1117                          * Backwards scanning YAFFS2: The old one is what
1118                          * we use, dump the new one.
1119                          * YAFFS1: Get both sets of tags and compare serial
1120                          * numbers.
1121                          */
1122
1123                         if (in_scan > 0) {
1124                                 /* Only do this for forward scanning */
1125                                 yaffs_rd_chunk_tags_nand(dev,
1126                                                          nand_chunk,
1127                                                          NULL, &new_tags);
1128
1129                                 /* Do a proper find */
1130                                 existing_cunk =
1131                                     yaffs_find_chunk_in_file(in, inode_chunk,
1132                                                              &existing_tags);
1133                         }
1134
1135                         if (existing_cunk <= 0) {
1136                                 /*Hoosterman - how did this happen? */
1137
1138                                 yaffs_trace(YAFFS_TRACE_ERROR,
1139                                         "yaffs tragedy: existing chunk < 0 in scan"
1140                                         );
1141
1142                         }
1143
1144                         /* NB The deleted flags should be false, otherwise
1145                          * the chunks will not be loaded during a scan
1146                          */
1147
1148                         if (in_scan > 0) {
1149                                 new_serial = new_tags.serial_number;
1150                                 existing_serial = existing_tags.serial_number;
1151                         }
1152
1153                         if ((in_scan > 0) &&
1154                             (existing_cunk <= 0 ||
1155                              ((existing_serial + 1) & 3) == new_serial)) {
1156                                 /* Forward scanning.
1157                                  * Use new
1158                                  * Delete the old one and drop through to
1159                                  * update the tnode
1160                                  */
1161                                 yaffs_chunk_del(dev, existing_cunk, 1,
1162                                                 __LINE__);
1163                         } else {
1164                                 /* Backward scanning or we want to use the
1165                                  * existing one
1166                                  * Delete the new one and return early so that
1167                                  * the tnode isn't changed
1168                                  */
1169                                 yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
1170                                 return YAFFS_OK;
1171                         }
1172                 }
1173
1174         }
1175
1176         if (existing_cunk == 0)
1177                 in->n_data_chunks++;
1178
1179         yaffs_load_tnode_0(dev, tn, inode_chunk, nand_chunk);
1180
1181         return YAFFS_OK;
1182 }
1183
1184 static void yaffs_soft_del_chunk(struct yaffs_dev *dev, int chunk)
1185 {
1186         struct yaffs_block_info *the_block;
1187         unsigned block_no;
1188
1189         yaffs_trace(YAFFS_TRACE_DELETION, "soft delete chunk %d", chunk);
1190
1191         block_no = chunk / dev->param.chunks_per_block;
1192         the_block = yaffs_get_block_info(dev, block_no);
1193         if (the_block) {
1194                 the_block->soft_del_pages++;
1195                 dev->n_free_chunks++;
1196                 yaffs2_update_oldest_dirty_seq(dev, block_no, the_block);
1197         }
1198 }
1199
1200 /* SoftDeleteWorker scans backwards through the tnode tree and soft deletes all
1201  * the chunks in the file.
1202  * All soft deleting does is increment the block's softdelete count and pulls
1203  * the chunk out of the tnode.
1204  * Thus, essentially this is the same as DeleteWorker except that the chunks
1205  * are soft deleted.
1206  */
1207
1208 static int yaffs_soft_del_worker(struct yaffs_obj *in, struct yaffs_tnode *tn,
1209                                  u32 level, int chunk_offset)
1210 {
1211         int i;
1212         int the_chunk;
1213         int all_done = 1;
1214         struct yaffs_dev *dev = in->my_dev;
1215
1216         if (!tn)
1217                 return 1;
1218
1219         if (level > 0) {
1220                 for (i = YAFFS_NTNODES_INTERNAL - 1;
1221                         all_done && i >= 0;
1222                         i--) {
1223                         if (tn->internal[i]) {
1224                                 all_done =
1225                                     yaffs_soft_del_worker(in,
1226                                         tn->internal[i],
1227                                         level - 1,
1228                                         (chunk_offset <<
1229                                         YAFFS_TNODES_INTERNAL_BITS)
1230                                         + i);
1231                                 if (all_done) {
1232                                         yaffs_free_tnode(dev,
1233                                                 tn->internal[i]);
1234                                         tn->internal[i] = NULL;
1235                                 } else {
1236                                         /* Can this happen? */
1237                                 }
1238                         }
1239                 }
1240                 return (all_done) ? 1 : 0;
1241         }
1242
1243         /* level 0 */
1244          for (i = YAFFS_NTNODES_LEVEL0 - 1; i >= 0; i--) {
1245                 the_chunk = yaffs_get_group_base(dev, tn, i);
1246                 if (the_chunk) {
1247                         yaffs_soft_del_chunk(dev, the_chunk);
1248                         yaffs_load_tnode_0(dev, tn, i, 0);
1249                 }
1250         }
1251         return 1;
1252 }
1253
1254 static void yaffs_remove_obj_from_dir(struct yaffs_obj *obj)
1255 {
1256         struct yaffs_dev *dev = obj->my_dev;
1257         struct yaffs_obj *parent;
1258
1259         yaffs_verify_obj_in_dir(obj);
1260         parent = obj->parent;
1261
1262         yaffs_verify_dir(parent);
1263
1264         if (dev && dev->param.remove_obj_fn)
1265                 dev->param.remove_obj_fn(obj);
1266
1267         list_del_init(&obj->siblings);
1268         obj->parent = NULL;
1269
1270         yaffs_verify_dir(parent);
1271 }
1272
1273 void yaffs_add_obj_to_dir(struct yaffs_obj *directory, struct yaffs_obj *obj)
1274 {
1275         if (!directory) {
1276                 yaffs_trace(YAFFS_TRACE_ALWAYS,
1277                         "tragedy: Trying to add an object to a null pointer directory"
1278                         );
1279                 BUG();
1280                 return;
1281         }
1282         if (directory->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
1283                 yaffs_trace(YAFFS_TRACE_ALWAYS,
1284                         "tragedy: Trying to add an object to a non-directory"
1285                         );
1286                 BUG();
1287         }
1288
1289         if (obj->siblings.prev == NULL) {
1290                 /* Not initialised */
1291                 BUG();
1292         }
1293
1294         yaffs_verify_dir(directory);
1295
1296         yaffs_remove_obj_from_dir(obj);
1297
1298         /* Now add it */
1299         list_add(&obj->siblings, &directory->variant.dir_variant.children);
1300         obj->parent = directory;
1301
1302         if (directory == obj->my_dev->unlinked_dir
1303             || directory == obj->my_dev->del_dir) {
1304                 obj->unlinked = 1;
1305                 obj->my_dev->n_unlinked_files++;
1306                 obj->rename_allowed = 0;
1307         }
1308
1309         yaffs_verify_dir(directory);
1310         yaffs_verify_obj_in_dir(obj);
1311 }
1312
1313 static int yaffs_change_obj_name(struct yaffs_obj *obj,
1314                                  struct yaffs_obj *new_dir,
1315                                  const YCHAR *new_name, int force, int shadows)
1316 {
1317         int unlink_op;
1318         int del_op;
1319         struct yaffs_obj *existing_target;
1320
1321         if (new_dir == NULL)
1322                 new_dir = obj->parent;  /* use the old directory */
1323
1324         if (new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
1325                 yaffs_trace(YAFFS_TRACE_ALWAYS,
1326                         "tragedy: yaffs_change_obj_name: new_dir is not a directory"
1327                         );
1328                 BUG();
1329         }
1330
1331         unlink_op = (new_dir == obj->my_dev->unlinked_dir);
1332         del_op = (new_dir == obj->my_dev->del_dir);
1333
1334         existing_target = yaffs_find_by_name(new_dir, new_name);
1335
1336         /* If the object is a file going into the unlinked directory,
1337          *   then it is OK to just stuff it in since duplicate names are OK.
1338          *   else only proceed if the new name does not exist and we're putting
1339          *   it into a directory.
1340          */
1341         if (!(unlink_op || del_op || force ||
1342               shadows > 0 || !existing_target) ||
1343               new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
1344                 return YAFFS_FAIL;
1345
1346         yaffs_set_obj_name(obj, new_name);
1347         obj->dirty = 1;
1348         yaffs_add_obj_to_dir(new_dir, obj);
1349
1350         if (unlink_op)
1351                 obj->unlinked = 1;
1352
1353         /* If it is a deletion then we mark it as a shrink for gc  */
1354         if (yaffs_update_oh(obj, new_name, 0, del_op, shadows, NULL) >= 0)
1355                 return YAFFS_OK;
1356
1357         return YAFFS_FAIL;
1358 }
1359
1360 /*------------------------ Short Operations Cache ------------------------------
1361  *   In many situations where there is no high level buffering  a lot of
1362  *   reads might be short sequential reads, and a lot of writes may be short
1363  *   sequential writes. eg. scanning/writing a jpeg file.
1364  *   In these cases, a short read/write cache can provide a huge perfomance
1365  *   benefit with dumb-as-a-rock code.
1366  *   In Linux, the page cache provides read buffering and the short op cache
1367  *   provides write buffering.
1368  *
1369  *   There are a small number (~10) of cache chunks per device so that we don't
1370  *   need a very intelligent search.
1371  */
1372
1373 static int yaffs_obj_cache_dirty(struct yaffs_obj *obj)
1374 {
1375         struct yaffs_dev *dev = obj->my_dev;
1376         int i;
1377         struct yaffs_cache *cache;
1378         int n_caches = obj->my_dev->param.n_caches;
1379
1380         for (i = 0; i < n_caches; i++) {
1381                 cache = &dev->cache[i];
1382                 if (cache->object == obj && cache->dirty)
1383                         return 1;
1384         }
1385
1386         return 0;
1387 }
1388
1389 static void yaffs_flush_file_cache(struct yaffs_obj *obj)
1390 {
1391         struct yaffs_dev *dev = obj->my_dev;
1392         int lowest = -99;       /* Stop compiler whining. */
1393         int i;
1394         struct yaffs_cache *cache;
1395         int chunk_written = 0;
1396         int n_caches = obj->my_dev->param.n_caches;
1397
1398         if (n_caches < 1)
1399                 return;
1400         do {
1401                 cache = NULL;
1402
1403                 /* Find the lowest dirty chunk for this object */
1404                 for (i = 0; i < n_caches; i++) {
1405                         if (dev->cache[i].object == obj &&
1406                             dev->cache[i].dirty) {
1407                                 if (!cache ||
1408                                     dev->cache[i].chunk_id < lowest) {
1409                                         cache = &dev->cache[i];
1410                                         lowest = cache->chunk_id;
1411                                 }
1412                         }
1413                 }
1414
1415                 if (cache && !cache->locked) {
1416                         /* Write it out and free it up */
1417                         chunk_written =
1418                             yaffs_wr_data_obj(cache->object,
1419                                               cache->chunk_id,
1420                                               cache->data,
1421                                               cache->n_bytes, 1);
1422                         cache->dirty = 0;
1423                         cache->object = NULL;
1424                 }
1425         } while (cache && chunk_written > 0);
1426
1427         if (cache)
1428                 /* Hoosterman, disk full while writing cache out. */
1429                 yaffs_trace(YAFFS_TRACE_ERROR,
1430                         "yaffs tragedy: no space during cache write");
1431 }
1432
1433 /*yaffs_flush_whole_cache(dev)
1434  *
1435  *
1436  */
1437
1438 void yaffs_flush_whole_cache(struct yaffs_dev *dev)
1439 {
1440         struct yaffs_obj *obj;
1441         int n_caches = dev->param.n_caches;
1442         int i;
1443
1444         /* Find a dirty object in the cache and flush it...
1445          * until there are no further dirty objects.
1446          */
1447         do {
1448                 obj = NULL;
1449                 for (i = 0; i < n_caches && !obj; i++) {
1450                         if (dev->cache[i].object && dev->cache[i].dirty)
1451                                 obj = dev->cache[i].object;
1452                 }
1453                 if (obj)
1454                         yaffs_flush_file_cache(obj);
1455         } while (obj);
1456
1457 }
1458
1459 /* Grab us a cache chunk for use.
1460  * First look for an empty one.
1461  * Then look for the least recently used non-dirty one.
1462  * Then look for the least recently used dirty one...., flush and look again.
1463  */
1464 static struct yaffs_cache *yaffs_grab_chunk_worker(struct yaffs_dev *dev)
1465 {
1466         int i;
1467
1468         if (dev->param.n_caches > 0) {
1469                 for (i = 0; i < dev->param.n_caches; i++) {
1470                         if (!dev->cache[i].object)
1471                                 return &dev->cache[i];
1472                 }
1473         }
1474         return NULL;
1475 }
1476
1477 static struct yaffs_cache *yaffs_grab_chunk_cache(struct yaffs_dev *dev)
1478 {
1479         struct yaffs_cache *cache;
1480         struct yaffs_obj *the_obj;
1481         int usage;
1482         int i;
1483         int pushout;
1484
1485         if (dev->param.n_caches < 1)
1486                 return NULL;
1487
1488         /* Try find a non-dirty one... */
1489
1490         cache = yaffs_grab_chunk_worker(dev);
1491
1492         if (!cache) {
1493                 /* They were all dirty, find the LRU object and flush
1494                  * its cache, then  find again.
1495                  * NB what's here is not very accurate,
1496                  * we actually flush the object with the LRU chunk.
1497                  */
1498
1499                 /* With locking we can't assume we can use entry zero,
1500                  * Set the_obj to a valid pointer for Coverity. */
1501                 the_obj = dev->cache[0].object;
1502                 usage = -1;
1503                 cache = NULL;
1504                 pushout = -1;
1505
1506                 for (i = 0; i < dev->param.n_caches; i++) {
1507                         if (dev->cache[i].object &&
1508                             !dev->cache[i].locked &&
1509                             (dev->cache[i].last_use < usage ||
1510                             !cache)) {
1511                                 usage = dev->cache[i].last_use;
1512                                 the_obj = dev->cache[i].object;
1513                                 cache = &dev->cache[i];
1514                                 pushout = i;
1515                         }
1516                 }
1517
1518                 if (!cache || cache->dirty) {
1519                         /* Flush and try again */
1520                         yaffs_flush_file_cache(the_obj);
1521                         cache = yaffs_grab_chunk_worker(dev);
1522                 }
1523         }
1524         return cache;
1525 }
1526
1527 /* Find a cached chunk */
1528 static struct yaffs_cache *yaffs_find_chunk_cache(const struct yaffs_obj *obj,
1529                                                   int chunk_id)
1530 {
1531         struct yaffs_dev *dev = obj->my_dev;
1532         int i;
1533
1534         if (dev->param.n_caches < 1)
1535                 return NULL;
1536
1537         for (i = 0; i < dev->param.n_caches; i++) {
1538                 if (dev->cache[i].object == obj &&
1539                     dev->cache[i].chunk_id == chunk_id) {
1540                         dev->cache_hits++;
1541
1542                         return &dev->cache[i];
1543                 }
1544         }
1545         return NULL;
1546 }
1547
1548 /* Mark the chunk for the least recently used algorithym */
1549 static void yaffs_use_cache(struct yaffs_dev *dev, struct yaffs_cache *cache,
1550                             int is_write)
1551 {
1552         int i;
1553
1554         if (dev->param.n_caches < 1)
1555                 return;
1556
1557         if (dev->cache_last_use < 0 ||
1558                 dev->cache_last_use > 100000000) {
1559                 /* Reset the cache usages */
1560                 for (i = 1; i < dev->param.n_caches; i++)
1561                         dev->cache[i].last_use = 0;
1562
1563                 dev->cache_last_use = 0;
1564         }
1565         dev->cache_last_use++;
1566         cache->last_use = dev->cache_last_use;
1567
1568         if (is_write)
1569                 cache->dirty = 1;
1570 }
1571
1572 /* Invalidate a single cache page.
1573  * Do this when a whole page gets written,
1574  * ie the short cache for this page is no longer valid.
1575  */
1576 static void yaffs_invalidate_chunk_cache(struct yaffs_obj *object, int chunk_id)
1577 {
1578         struct yaffs_cache *cache;
1579
1580         if (object->my_dev->param.n_caches > 0) {
1581                 cache = yaffs_find_chunk_cache(object, chunk_id);
1582
1583                 if (cache)
1584                         cache->object = NULL;
1585         }
1586 }
1587
1588 /* Invalidate all the cache pages associated with this object
1589  * Do this whenever ther file is deleted or resized.
1590  */
1591 static void yaffs_invalidate_whole_cache(struct yaffs_obj *in)
1592 {
1593         int i;
1594         struct yaffs_dev *dev = in->my_dev;
1595
1596         if (dev->param.n_caches > 0) {
1597                 /* Invalidate it. */
1598                 for (i = 0; i < dev->param.n_caches; i++) {
1599                         if (dev->cache[i].object == in)
1600                                 dev->cache[i].object = NULL;
1601                 }
1602         }
1603 }
1604
1605 static void yaffs_unhash_obj(struct yaffs_obj *obj)
1606 {
1607         int bucket;
1608         struct yaffs_dev *dev = obj->my_dev;
1609
1610         /* If it is still linked into the bucket list, free from the list */
1611         if (!list_empty(&obj->hash_link)) {
1612                 list_del_init(&obj->hash_link);
1613                 bucket = yaffs_hash_fn(obj->obj_id);
1614                 dev->obj_bucket[bucket].count--;
1615         }
1616 }
1617
1618 /*  FreeObject frees up a Object and puts it back on the free list */
1619 static void yaffs_free_obj(struct yaffs_obj *obj)
1620 {
1621         struct yaffs_dev *dev;
1622
1623         if (!obj) {
1624                 BUG();
1625                 return;
1626         }
1627         dev = obj->my_dev;
1628         yaffs_trace(YAFFS_TRACE_OS, "FreeObject %p inode %p",
1629                 obj, obj->my_inode);
1630         if (obj->parent)
1631                 BUG();
1632         if (!list_empty(&obj->siblings))
1633                 BUG();
1634
1635         if (obj->my_inode) {
1636                 /* We're still hooked up to a cached inode.
1637                  * Don't delete now, but mark for later deletion
1638                  */
1639                 obj->defered_free = 1;
1640                 return;
1641         }
1642
1643         yaffs_unhash_obj(obj);
1644
1645         yaffs_free_raw_obj(dev, obj);
1646         dev->n_obj--;
1647         dev->checkpoint_blocks_required = 0;    /* force recalculation */
1648 }
1649
1650 void yaffs_handle_defered_free(struct yaffs_obj *obj)
1651 {
1652         if (obj->defered_free)
1653                 yaffs_free_obj(obj);
1654 }
1655
1656 static int yaffs_generic_obj_del(struct yaffs_obj *in)
1657 {
1658         /* Iinvalidate the file's data in the cache, without flushing. */
1659         yaffs_invalidate_whole_cache(in);
1660
1661         if (in->my_dev->param.is_yaffs2 && in->parent != in->my_dev->del_dir) {
1662                 /* Move to unlinked directory so we have a deletion record */
1663                 yaffs_change_obj_name(in, in->my_dev->del_dir, _Y("deleted"), 0,
1664                                       0);
1665         }
1666
1667         yaffs_remove_obj_from_dir(in);
1668         yaffs_chunk_del(in->my_dev, in->hdr_chunk, 1, __LINE__);
1669         in->hdr_chunk = 0;
1670
1671         yaffs_free_obj(in);
1672         return YAFFS_OK;
1673
1674 }
1675
1676 static void yaffs_soft_del_file(struct yaffs_obj *obj)
1677 {
1678         if (!obj->deleted ||
1679             obj->variant_type != YAFFS_OBJECT_TYPE_FILE ||
1680             obj->soft_del)
1681                 return;
1682
1683         if (obj->n_data_chunks <= 0) {
1684                 /* Empty file with no duplicate object headers,
1685                  * just delete it immediately */
1686                 yaffs_free_tnode(obj->my_dev, obj->variant.file_variant.top);
1687                 obj->variant.file_variant.top = NULL;
1688                 yaffs_trace(YAFFS_TRACE_TRACING,
1689                         "yaffs: Deleting empty file %d",
1690                         obj->obj_id);
1691                 yaffs_generic_obj_del(obj);
1692         } else {
1693                 yaffs_soft_del_worker(obj,
1694                                       obj->variant.file_variant.top,
1695                                       obj->variant.
1696                                       file_variant.top_level, 0);
1697                 obj->soft_del = 1;
1698         }
1699 }
1700
1701 /* Pruning removes any part of the file structure tree that is beyond the
1702  * bounds of the file (ie that does not point to chunks).
1703  *
1704  * A file should only get pruned when its size is reduced.
1705  *
1706  * Before pruning, the chunks must be pulled from the tree and the
1707  * level 0 tnode entries must be zeroed out.
1708  * Could also use this for file deletion, but that's probably better handled
1709  * by a special case.
1710  *
1711  * This function is recursive. For levels > 0 the function is called again on
1712  * any sub-tree. For level == 0 we just check if the sub-tree has data.
1713  * If there is no data in a subtree then it is pruned.
1714  */
1715
1716 static struct yaffs_tnode *yaffs_prune_worker(struct yaffs_dev *dev,
1717                                               struct yaffs_tnode *tn, u32 level,
1718                                               int del0)
1719 {
1720         int i;
1721         int has_data;
1722
1723         if (!tn)
1724                 return tn;
1725
1726         has_data = 0;
1727
1728         if (level > 0) {
1729                 for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++) {
1730                         if (tn->internal[i]) {
1731                                 tn->internal[i] =
1732                                     yaffs_prune_worker(dev,
1733                                                 tn->internal[i],
1734                                                 level - 1,
1735                                                 (i == 0) ? del0 : 1);
1736                         }
1737
1738                         if (tn->internal[i])
1739                                 has_data++;
1740                 }
1741         } else {
1742                 int tnode_size_u32 = dev->tnode_size / sizeof(u32);
1743                 u32 *map = (u32 *) tn;
1744
1745                 for (i = 0; !has_data && i < tnode_size_u32; i++) {
1746                         if (map[i])
1747                                 has_data++;
1748                 }
1749         }
1750
1751         if (has_data == 0 && del0) {
1752                 /* Free and return NULL */
1753                 yaffs_free_tnode(dev, tn);
1754                 tn = NULL;
1755         }
1756         return tn;
1757 }
1758
1759 static int yaffs_prune_tree(struct yaffs_dev *dev,
1760                             struct yaffs_file_var *file_struct)
1761 {
1762         int i;
1763         int has_data;
1764         int done = 0;
1765         struct yaffs_tnode *tn;
1766
1767         if (file_struct->top_level < 1)
1768                 return YAFFS_OK;
1769
1770         file_struct->top =
1771            yaffs_prune_worker(dev, file_struct->top, file_struct->top_level, 0);
1772
1773         /* Now we have a tree with all the non-zero branches NULL but
1774          * the height is the same as it was.
1775          * Let's see if we can trim internal tnodes to shorten the tree.
1776          * We can do this if only the 0th element in the tnode is in use
1777          * (ie all the non-zero are NULL)
1778          */
1779
1780         while (file_struct->top_level && !done) {
1781                 tn = file_struct->top;
1782
1783                 has_data = 0;
1784                 for (i = 1; i < YAFFS_NTNODES_INTERNAL; i++) {
1785                         if (tn->internal[i])
1786                                 has_data++;
1787                 }
1788
1789                 if (!has_data) {
1790                         file_struct->top = tn->internal[0];
1791                         file_struct->top_level--;
1792                         yaffs_free_tnode(dev, tn);
1793                 } else {
1794                         done = 1;
1795                 }
1796         }
1797
1798         return YAFFS_OK;
1799 }
1800
1801 /*-------------------- End of File Structure functions.-------------------*/
1802
1803 /* alloc_empty_obj gets us a clean Object.*/
1804 static struct yaffs_obj *yaffs_alloc_empty_obj(struct yaffs_dev *dev)
1805 {
1806         struct yaffs_obj *obj = yaffs_alloc_raw_obj(dev);
1807
1808         if (!obj)
1809                 return obj;
1810
1811         dev->n_obj++;
1812
1813         /* Now sweeten it up... */
1814
1815         memset(obj, 0, sizeof(struct yaffs_obj));
1816         obj->being_created = 1;
1817
1818         obj->my_dev = dev;
1819         obj->hdr_chunk = 0;
1820         obj->variant_type = YAFFS_OBJECT_TYPE_UNKNOWN;
1821         INIT_LIST_HEAD(&(obj->hard_links));
1822         INIT_LIST_HEAD(&(obj->hash_link));
1823         INIT_LIST_HEAD(&obj->siblings);
1824
1825         /* Now make the directory sane */
1826         if (dev->root_dir) {
1827                 obj->parent = dev->root_dir;
1828                 list_add(&(obj->siblings),
1829                          &dev->root_dir->variant.dir_variant.children);
1830         }
1831
1832         /* Add it to the lost and found directory.
1833          * NB Can't put root or lost-n-found in lost-n-found so
1834          * check if lost-n-found exists first
1835          */
1836         if (dev->lost_n_found)
1837                 yaffs_add_obj_to_dir(dev->lost_n_found, obj);
1838
1839         obj->being_created = 0;
1840
1841         dev->checkpoint_blocks_required = 0;    /* force recalculation */
1842
1843         return obj;
1844 }
1845
1846 static int yaffs_find_nice_bucket(struct yaffs_dev *dev)
1847 {
1848         int i;
1849         int l = 999;
1850         int lowest = 999999;
1851
1852         /* Search for the shortest list or one that
1853          * isn't too long.
1854          */
1855
1856         for (i = 0; i < 10 && lowest > 4; i++) {
1857                 dev->bucket_finder++;
1858                 dev->bucket_finder %= YAFFS_NOBJECT_BUCKETS;
1859                 if (dev->obj_bucket[dev->bucket_finder].count < lowest) {
1860                         lowest = dev->obj_bucket[dev->bucket_finder].count;
1861                         l = dev->bucket_finder;
1862                 }
1863         }
1864
1865         return l;
1866 }
1867
1868 static int yaffs_new_obj_id(struct yaffs_dev *dev)
1869 {
1870         int bucket = yaffs_find_nice_bucket(dev);
1871         int found = 0;
1872         struct list_head *i;
1873         u32 n = (u32) bucket;
1874
1875         /* Now find an object value that has not already been taken
1876          * by scanning the list.
1877          */
1878
1879         while (!found) {
1880                 found = 1;
1881                 n += YAFFS_NOBJECT_BUCKETS;
1882                 if (1 || dev->obj_bucket[bucket].count > 0) {
1883                         list_for_each(i, &dev->obj_bucket[bucket].list) {
1884                                 /* If there is already one in the list */
1885                                 if (i && list_entry(i, struct yaffs_obj,
1886                                                     hash_link)->obj_id == n) {
1887                                         found = 0;
1888                                 }
1889                         }
1890                 }
1891         }
1892         return n;
1893 }
1894
1895 static void yaffs_hash_obj(struct yaffs_obj *in)
1896 {
1897         int bucket = yaffs_hash_fn(in->obj_id);
1898         struct yaffs_dev *dev = in->my_dev;
1899
1900         list_add(&in->hash_link, &dev->obj_bucket[bucket].list);
1901         dev->obj_bucket[bucket].count++;
1902 }
1903
1904 struct yaffs_obj *yaffs_find_by_number(struct yaffs_dev *dev, u32 number)
1905 {
1906         int bucket = yaffs_hash_fn(number);
1907         struct list_head *i;
1908         struct yaffs_obj *in;
1909
1910         list_for_each(i, &dev->obj_bucket[bucket].list) {
1911                 /* Look if it is in the list */
1912                 in = list_entry(i, struct yaffs_obj, hash_link);
1913                 if (in->obj_id == number) {
1914                         /* Don't show if it is defered free */
1915                         if (in->defered_free)
1916                                 return NULL;
1917                         return in;
1918                 }
1919         }
1920
1921         return NULL;
1922 }
1923
1924 struct yaffs_obj *yaffs_new_obj(struct yaffs_dev *dev, int number,
1925                                 enum yaffs_obj_type type)
1926 {
1927         struct yaffs_obj *the_obj = NULL;
1928         struct yaffs_tnode *tn = NULL;
1929
1930         if (number < 0)
1931                 number = yaffs_new_obj_id(dev);
1932
1933         if (type == YAFFS_OBJECT_TYPE_FILE) {
1934                 tn = yaffs_get_tnode(dev);
1935                 if (!tn)
1936                         return NULL;
1937         }
1938
1939         the_obj = yaffs_alloc_empty_obj(dev);
1940         if (!the_obj) {
1941                 if (tn)
1942                         yaffs_free_tnode(dev, tn);
1943                 return NULL;
1944         }
1945
1946         the_obj->fake = 0;
1947         the_obj->rename_allowed = 1;
1948         the_obj->unlink_allowed = 1;
1949         the_obj->obj_id = number;
1950         yaffs_hash_obj(the_obj);
1951         the_obj->variant_type = type;
1952         yaffs_load_current_time(the_obj, 1, 1);
1953
1954         switch (type) {
1955         case YAFFS_OBJECT_TYPE_FILE:
1956                 the_obj->variant.file_variant.file_size = 0;
1957                 the_obj->variant.file_variant.scanned_size = 0;
1958                 the_obj->variant.file_variant.shrink_size = ~0; /* max */
1959                 the_obj->variant.file_variant.top_level = 0;
1960                 the_obj->variant.file_variant.top = tn;
1961                 break;
1962         case YAFFS_OBJECT_TYPE_DIRECTORY:
1963                 INIT_LIST_HEAD(&the_obj->variant.dir_variant.children);
1964                 INIT_LIST_HEAD(&the_obj->variant.dir_variant.dirty);
1965                 break;
1966         case YAFFS_OBJECT_TYPE_SYMLINK:
1967         case YAFFS_OBJECT_TYPE_HARDLINK:
1968         case YAFFS_OBJECT_TYPE_SPECIAL:
1969                 /* No action required */
1970                 break;
1971         case YAFFS_OBJECT_TYPE_UNKNOWN:
1972                 /* todo this should not happen */
1973                 break;
1974         }
1975         return the_obj;
1976 }
1977
1978 static struct yaffs_obj *yaffs_create_fake_dir(struct yaffs_dev *dev,
1979                                                int number, u32 mode)
1980 {
1981
1982         struct yaffs_obj *obj =
1983             yaffs_new_obj(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
1984
1985         if (!obj)
1986                 return NULL;
1987
1988         obj->fake = 1;  /* it is fake so it might not use NAND */
1989         obj->rename_allowed = 0;
1990         obj->unlink_allowed = 0;
1991         obj->deleted = 0;
1992         obj->unlinked = 0;
1993         obj->yst_mode = mode;
1994         obj->my_dev = dev;
1995         obj->hdr_chunk = 0;     /* Not a valid chunk. */
1996         return obj;
1997
1998 }
1999
2000
2001 static void yaffs_init_tnodes_and_objs(struct yaffs_dev *dev)
2002 {
2003         int i;
2004
2005         dev->n_obj = 0;
2006         dev->n_tnodes = 0;
2007         yaffs_init_raw_tnodes_and_objs(dev);
2008
2009         for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
2010                 INIT_LIST_HEAD(&dev->obj_bucket[i].list);
2011                 dev->obj_bucket[i].count = 0;
2012         }
2013 }
2014
2015 struct yaffs_obj *yaffs_find_or_create_by_number(struct yaffs_dev *dev,
2016                                                  int number,
2017                                                  enum yaffs_obj_type type)
2018 {
2019         struct yaffs_obj *the_obj = NULL;
2020
2021         if (number > 0)
2022                 the_obj = yaffs_find_by_number(dev, number);
2023
2024         if (!the_obj)
2025                 the_obj = yaffs_new_obj(dev, number, type);
2026
2027         return the_obj;
2028
2029 }
2030
2031 YCHAR *yaffs_clone_str(const YCHAR *str)
2032 {
2033         YCHAR *new_str = NULL;
2034         int len;
2035
2036         if (!str)
2037                 str = _Y("");
2038
2039         len = strnlen(str, YAFFS_MAX_ALIAS_LENGTH);
2040         new_str = kmalloc((len + 1) * sizeof(YCHAR), GFP_NOFS);
2041         if (new_str) {
2042                 strncpy(new_str, str, len);
2043                 new_str[len] = 0;
2044         }
2045         return new_str;
2046
2047 }
2048 /*
2049  *yaffs_update_parent() handles fixing a directories mtime and ctime when a new
2050  * link (ie. name) is created or deleted in the directory.
2051  *
2052  * ie.
2053  *   create dir/a : update dir's mtime/ctime
2054  *   rm dir/a:   update dir's mtime/ctime
2055  *   modify dir/a: don't update dir's mtimme/ctime
2056  *
2057  * This can be handled immediately or defered. Defering helps reduce the number
2058  * of updates when many files in a directory are changed within a brief period.
2059  *
2060  * If the directory updating is defered then yaffs_update_dirty_dirs must be
2061  * called periodically.
2062  */
2063
2064 static void yaffs_update_parent(struct yaffs_obj *obj)
2065 {
2066         struct yaffs_dev *dev;
2067
2068         if (!obj)
2069                 return;
2070         dev = obj->my_dev;
2071         obj->dirty = 1;
2072         yaffs_load_current_time(obj, 0, 1);
2073         if (dev->param.defered_dir_update) {
2074                 struct list_head *link = &obj->variant.dir_variant.dirty;
2075
2076                 if (list_empty(link)) {
2077                         list_add(link, &dev->dirty_dirs);
2078                         yaffs_trace(YAFFS_TRACE_BACKGROUND,
2079                           "Added object %d to dirty directories",
2080                            obj->obj_id);
2081                 }
2082
2083         } else {
2084                 yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
2085         }
2086 }
2087
2088 void yaffs_update_dirty_dirs(struct yaffs_dev *dev)
2089 {
2090         struct list_head *link;
2091         struct yaffs_obj *obj;
2092         struct yaffs_dir_var *d_s;
2093         union yaffs_obj_var *o_v;
2094
2095         yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update dirty directories");
2096
2097         while (!list_empty(&dev->dirty_dirs)) {
2098                 link = dev->dirty_dirs.next;
2099                 list_del_init(link);
2100
2101                 d_s = list_entry(link, struct yaffs_dir_var, dirty);
2102                 o_v = list_entry(d_s, union yaffs_obj_var, dir_variant);
2103                 obj = list_entry(o_v, struct yaffs_obj, variant);
2104
2105                 yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update directory %d",
2106                         obj->obj_id);
2107
2108                 if (obj->dirty)
2109                         yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
2110         }
2111 }
2112
2113 /*
2114  * Mknod (create) a new object.
2115  * equiv_obj only has meaning for a hard link;
2116  * alias_str only has meaning for a symlink.
2117  * rdev only has meaning for devices (a subset of special objects)
2118  */
2119
2120 static struct yaffs_obj *yaffs_create_obj(enum yaffs_obj_type type,
2121                                           struct yaffs_obj *parent,
2122                                           const YCHAR *name,
2123                                           u32 mode,
2124                                           u32 uid,
2125                                           u32 gid,
2126                                           struct yaffs_obj *equiv_obj,
2127                                           const YCHAR *alias_str, u32 rdev)
2128 {
2129         struct yaffs_obj *in;
2130         YCHAR *str = NULL;
2131         struct yaffs_dev *dev = parent->my_dev;
2132
2133         /* Check if the entry exists.
2134          * If it does then fail the call since we don't want a dup. */
2135         if (yaffs_find_by_name(parent, name))
2136                 return NULL;
2137
2138         if (type == YAFFS_OBJECT_TYPE_SYMLINK) {
2139                 str = yaffs_clone_str(alias_str);
2140                 if (!str)
2141                         return NULL;
2142         }
2143
2144         in = yaffs_new_obj(dev, -1, type);
2145
2146         if (!in) {
2147                 kfree(str);
2148                 return NULL;
2149         }
2150
2151         in->hdr_chunk = 0;
2152         in->valid = 1;
2153         in->variant_type = type;
2154
2155         in->yst_mode = mode;
2156
2157         yaffs_attribs_init(in, gid, uid, rdev);
2158
2159         in->n_data_chunks = 0;
2160
2161         yaffs_set_obj_name(in, name);
2162         in->dirty = 1;
2163
2164         yaffs_add_obj_to_dir(parent, in);
2165
2166         in->my_dev = parent->my_dev;
2167
2168         switch (type) {
2169         case YAFFS_OBJECT_TYPE_SYMLINK:
2170                 in->variant.symlink_variant.alias = str;
2171                 break;
2172         case YAFFS_OBJECT_TYPE_HARDLINK:
2173                 in->variant.hardlink_variant.equiv_obj = equiv_obj;
2174                 in->variant.hardlink_variant.equiv_id = equiv_obj->obj_id;
2175                 list_add(&in->hard_links, &equiv_obj->hard_links);
2176                 break;
2177         case YAFFS_OBJECT_TYPE_FILE:
2178         case YAFFS_OBJECT_TYPE_DIRECTORY:
2179         case YAFFS_OBJECT_TYPE_SPECIAL:
2180         case YAFFS_OBJECT_TYPE_UNKNOWN:
2181                 /* do nothing */
2182                 break;
2183         }
2184
2185         if (yaffs_update_oh(in, name, 0, 0, 0, NULL) < 0) {
2186                 /* Could not create the object header, fail */
2187                 yaffs_del_obj(in);
2188                 in = NULL;
2189         }
2190
2191         if (in)
2192                 yaffs_update_parent(parent);
2193
2194         return in;
2195 }
2196
2197 struct yaffs_obj *yaffs_create_file(struct yaffs_obj *parent,
2198                                     const YCHAR *name, u32 mode, u32 uid,
2199                                     u32 gid)
2200 {
2201         return yaffs_create_obj(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
2202                                 uid, gid, NULL, NULL, 0);
2203 }
2204
2205 struct yaffs_obj *yaffs_create_dir(struct yaffs_obj *parent, const YCHAR *name,
2206                                    u32 mode, u32 uid, u32 gid)
2207 {
2208         return yaffs_create_obj(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
2209                                 mode, uid, gid, NULL, NULL, 0);
2210 }
2211
2212 struct yaffs_obj *yaffs_create_special(struct yaffs_obj *parent,
2213                                        const YCHAR *name, u32 mode, u32 uid,
2214                                        u32 gid, u32 rdev)
2215 {
2216         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
2217                                 uid, gid, NULL, NULL, rdev);
2218 }
2219
2220 struct yaffs_obj *yaffs_create_symlink(struct yaffs_obj *parent,
2221                                        const YCHAR *name, u32 mode, u32 uid,
2222                                        u32 gid, const YCHAR *alias)
2223 {
2224         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
2225                                 uid, gid, NULL, alias, 0);
2226 }
2227
2228 /* yaffs_link_obj returns the object id of the equivalent object.*/
2229 struct yaffs_obj *yaffs_link_obj(struct yaffs_obj *parent, const YCHAR * name,
2230                                  struct yaffs_obj *equiv_obj)
2231 {
2232         /* Get the real object in case we were fed a hard link obj */
2233         equiv_obj = yaffs_get_equivalent_obj(equiv_obj);
2234
2235         if (yaffs_create_obj(YAFFS_OBJECT_TYPE_HARDLINK,
2236                         parent, name, 0, 0, 0,
2237                         equiv_obj, NULL, 0))
2238                 return equiv_obj;
2239
2240         return NULL;
2241
2242 }
2243
2244
2245
2246 /*---------------------- Block Management and Page Allocation -------------*/
2247
2248 static void yaffs_deinit_blocks(struct yaffs_dev *dev)
2249 {
2250         if (dev->block_info_alt && dev->block_info)
2251                 vfree(dev->block_info);
2252         else
2253                 kfree(dev->block_info);
2254
2255         dev->block_info_alt = 0;
2256
2257         dev->block_info = NULL;
2258
2259         if (dev->chunk_bits_alt && dev->chunk_bits)
2260                 vfree(dev->chunk_bits);
2261         else
2262                 kfree(dev->chunk_bits);
2263         dev->chunk_bits_alt = 0;
2264         dev->chunk_bits = NULL;
2265 }
2266
2267 static int yaffs_init_blocks(struct yaffs_dev *dev)
2268 {
2269         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
2270
2271         dev->block_info = NULL;
2272         dev->chunk_bits = NULL;
2273         dev->alloc_block = -1;  /* force it to get a new one */
2274
2275         /* If the first allocation strategy fails, thry the alternate one */
2276         dev->block_info =
2277                 kmalloc(n_blocks * sizeof(struct yaffs_block_info), GFP_NOFS);
2278         if (!dev->block_info) {
2279                 dev->block_info =
2280                     vmalloc(n_blocks * sizeof(struct yaffs_block_info));
2281                 dev->block_info_alt = 1;
2282         } else {
2283                 dev->block_info_alt = 0;
2284         }
2285
2286         if (!dev->block_info)
2287                 goto alloc_error;
2288
2289         /* Set up dynamic blockinfo stuff. Round up bytes. */
2290         dev->chunk_bit_stride = (dev->param.chunks_per_block + 7) / 8;
2291         dev->chunk_bits =
2292                 kmalloc(dev->chunk_bit_stride * n_blocks, GFP_NOFS);
2293         if (!dev->chunk_bits) {
2294                 dev->chunk_bits =
2295                     vmalloc(dev->chunk_bit_stride * n_blocks);
2296                 dev->chunk_bits_alt = 1;
2297         } else {
2298                 dev->chunk_bits_alt = 0;
2299         }
2300         if (!dev->chunk_bits)
2301                 goto alloc_error;
2302
2303
2304         memset(dev->block_info, 0, n_blocks * sizeof(struct yaffs_block_info));
2305         memset(dev->chunk_bits, 0, dev->chunk_bit_stride * n_blocks);
2306         return YAFFS_OK;
2307
2308 alloc_error:
2309         yaffs_deinit_blocks(dev);
2310         return YAFFS_FAIL;
2311 }
2312
2313
2314 void yaffs_block_became_dirty(struct yaffs_dev *dev, int block_no)
2315 {
2316         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block_no);
2317         int erased_ok = 0;
2318         int i;
2319
2320         /* If the block is still healthy erase it and mark as clean.
2321          * If the block has had a data failure, then retire it.
2322          */
2323
2324         yaffs_trace(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
2325                 "yaffs_block_became_dirty block %d state %d %s",
2326                 block_no, bi->block_state,
2327                 (bi->needs_retiring) ? "needs retiring" : "");
2328
2329         yaffs2_clear_oldest_dirty_seq(dev, bi);
2330
2331         bi->block_state = YAFFS_BLOCK_STATE_DIRTY;
2332
2333         /* If this is the block being garbage collected then stop gc'ing */
2334         if (block_no == dev->gc_block)
2335                 dev->gc_block = 0;
2336
2337         /* If this block is currently the best candidate for gc
2338          * then drop as a candidate */
2339         if (block_no == dev->gc_dirtiest) {
2340                 dev->gc_dirtiest = 0;
2341                 dev->gc_pages_in_use = 0;
2342         }
2343
2344         if (!bi->needs_retiring) {
2345                 yaffs2_checkpt_invalidate(dev);
2346                 erased_ok = yaffs_erase_block(dev, block_no);
2347                 if (!erased_ok) {
2348                         dev->n_erase_failures++;
2349                         yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
2350                           "**>> Erasure failed %d", block_no);
2351                 }
2352         }
2353
2354         /* Verify erasure if needed */
2355         if (erased_ok &&
2356             ((yaffs_trace_mask & YAFFS_TRACE_ERASE) ||
2357              !yaffs_skip_verification(dev))) {
2358                 for (i = 0; i < dev->param.chunks_per_block; i++) {
2359                         if (!yaffs_check_chunk_erased(dev,
2360                                 block_no * dev->param.chunks_per_block + i)) {
2361                                 yaffs_trace(YAFFS_TRACE_ERROR,
2362                                         ">>Block %d erasure supposedly OK, but chunk %d not erased",
2363                                         block_no, i);
2364                         }
2365                 }
2366         }
2367
2368         if (!erased_ok) {
2369                 /* We lost a block of free space */
2370                 dev->n_free_chunks -= dev->param.chunks_per_block;
2371                 yaffs_retire_block(dev, block_no);
2372                 yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
2373                         "**>> Block %d retired", block_no);
2374                 return;
2375         }
2376
2377         /* Clean it up... */
2378         bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
2379         bi->seq_number = 0;
2380         dev->n_erased_blocks++;
2381         bi->pages_in_use = 0;
2382         bi->soft_del_pages = 0;
2383         bi->has_shrink_hdr = 0;
2384         bi->skip_erased_check = 1;      /* Clean, so no need to check */
2385         bi->gc_prioritise = 0;
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                                 oh->file_size =
2500                                     object->variant.file_variant.file_size;
2501                                 tags.extra_length = oh->file_size;
2502                         }
2503
2504                         yaffs_verify_oh(object, oh, &tags, 1);
2505                         new_chunk =
2506                             yaffs_write_new_chunk(dev, (u8 *) oh, &tags, 1);
2507                 } else {
2508                         new_chunk =
2509                             yaffs_write_new_chunk(dev, buffer, &tags, 1);
2510                 }
2511
2512                 if (new_chunk < 0) {
2513                         ret_val = YAFFS_FAIL;
2514                 } else {
2515
2516                         /* Now fix up the Tnodes etc. */
2517
2518                         if (tags.chunk_id == 0) {
2519                                 /* It's a header */
2520                                 object->hdr_chunk = new_chunk;
2521                                 object->serial = tags.serial_number;
2522                         } else {
2523                                 /* It's a data chunk */
2524                                 yaffs_put_chunk_in_file(object, tags.chunk_id,
2525                                                         new_chunk, 0);
2526                         }
2527                 }
2528         }
2529         if (ret_val == YAFFS_OK)
2530                 yaffs_chunk_del(dev, old_chunk, mark_flash, __LINE__);
2531         return ret_val;
2532 }
2533
2534 static int yaffs_gc_block(struct yaffs_dev *dev, int block, int whole_block)
2535 {
2536         int old_chunk;
2537         int ret_val = YAFFS_OK;
2538         int i;
2539         int is_checkpt_block;
2540         int max_copies;
2541         int chunks_before = yaffs_get_erased_chunks(dev);
2542         int chunks_after;
2543         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block);
2544
2545         is_checkpt_block = (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT);
2546
2547         yaffs_trace(YAFFS_TRACE_TRACING,
2548                 "Collecting block %d, in use %d, shrink %d, whole_block %d",
2549                 block, bi->pages_in_use, bi->has_shrink_hdr,
2550                 whole_block);
2551
2552         /*yaffs_verify_free_chunks(dev); */
2553
2554         if (bi->block_state == YAFFS_BLOCK_STATE_FULL)
2555                 bi->block_state = YAFFS_BLOCK_STATE_COLLECTING;
2556
2557         bi->has_shrink_hdr = 0; /* clear the flag so that the block can erase */
2558
2559         dev->gc_disable = 1;
2560
2561         if (is_checkpt_block || !yaffs_still_some_chunks(dev, block)) {
2562                 yaffs_trace(YAFFS_TRACE_TRACING,
2563                         "Collecting block %d that has no chunks in use",
2564                         block);
2565                 yaffs_block_became_dirty(dev, block);
2566         } else {
2567
2568                 u8 *buffer = yaffs_get_temp_buffer(dev);
2569
2570                 yaffs_verify_blk(dev, bi, block);
2571
2572                 max_copies = (whole_block) ? dev->param.chunks_per_block : 5;
2573                 old_chunk = block * dev->param.chunks_per_block + dev->gc_chunk;
2574
2575                 for (/* init already done */ ;
2576                      ret_val == YAFFS_OK &&
2577                      dev->gc_chunk < dev->param.chunks_per_block &&
2578                      (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) &&
2579                      max_copies > 0;
2580                      dev->gc_chunk++, old_chunk++) {
2581                         if (yaffs_check_chunk_bit(dev, block, dev->gc_chunk)) {
2582                                 /* Page is in use and might need to be copied */
2583                                 max_copies--;
2584                                 ret_val = yaffs_gc_process_chunk(dev, bi,
2585                                                         old_chunk, buffer);
2586                         }
2587                 }
2588                 yaffs_release_temp_buffer(dev, buffer);
2589         }
2590
2591         yaffs_verify_collected_blk(dev, bi, block);
2592
2593         if (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
2594                 /*
2595                  * The gc did not complete. Set block state back to FULL
2596                  * because checkpointing does not restore gc.
2597                  */
2598                 bi->block_state = YAFFS_BLOCK_STATE_FULL;
2599         } else {
2600                 /* The gc completed. */
2601                 /* Do any required cleanups */
2602                 for (i = 0; i < dev->n_clean_ups; i++) {
2603                         /* Time to delete the file too */
2604                         struct yaffs_obj *object =
2605                             yaffs_find_by_number(dev, dev->gc_cleanup_list[i]);
2606                         if (object) {
2607                                 yaffs_free_tnode(dev,
2608                                           object->variant.file_variant.top);
2609                                 object->variant.file_variant.top = NULL;
2610                                 yaffs_trace(YAFFS_TRACE_GC,
2611                                         "yaffs: About to finally delete object %d",
2612                                         object->obj_id);
2613                                 yaffs_generic_obj_del(object);
2614                                 object->my_dev->n_deleted_files--;
2615                         }
2616
2617                 }
2618                 chunks_after = yaffs_get_erased_chunks(dev);
2619                 if (chunks_before >= chunks_after)
2620                         yaffs_trace(YAFFS_TRACE_GC,
2621                                 "gc did not increase free chunks before %d after %d",
2622                                 chunks_before, chunks_after);
2623                 dev->gc_block = 0;
2624                 dev->gc_chunk = 0;
2625                 dev->n_clean_ups = 0;
2626         }
2627
2628         dev->gc_disable = 0;
2629
2630         return ret_val;
2631 }
2632
2633 /*
2634  * find_gc_block() selects the dirtiest block (or close enough)
2635  * for garbage collection.
2636  */
2637
2638 static unsigned yaffs_find_gc_block(struct yaffs_dev *dev,
2639                                     int aggressive, int background)
2640 {
2641         int i;
2642         int iterations;
2643         unsigned selected = 0;
2644         int prioritised = 0;
2645         int prioritised_exist = 0;
2646         struct yaffs_block_info *bi;
2647         int threshold;
2648
2649         /* First let's see if we need to grab a prioritised block */
2650         if (dev->has_pending_prioritised_gc && !aggressive) {
2651                 dev->gc_dirtiest = 0;
2652                 bi = dev->block_info;
2653                 for (i = dev->internal_start_block;
2654                      i <= dev->internal_end_block && !selected; i++) {
2655
2656                         if (bi->gc_prioritise) {
2657                                 prioritised_exist = 1;
2658                                 if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2659                                     yaffs_block_ok_for_gc(dev, bi)) {
2660                                         selected = i;
2661                                         prioritised = 1;
2662                                 }
2663                         }
2664                         bi++;
2665                 }
2666
2667                 /*
2668                  * If there is a prioritised block and none was selected then
2669                  * this happened because there is at least one old dirty block
2670                  * gumming up the works. Let's gc the oldest dirty block.
2671                  */
2672
2673                 if (prioritised_exist &&
2674                     !selected && dev->oldest_dirty_block > 0)
2675                         selected = dev->oldest_dirty_block;
2676
2677                 if (!prioritised_exist) /* None found, so we can clear this */
2678                         dev->has_pending_prioritised_gc = 0;
2679         }
2680
2681         /* If we're doing aggressive GC then we are happy to take a less-dirty
2682          * block, and search harder.
2683          * else (leasurely gc), then we only bother to do this if the
2684          * block has only a few pages in use.
2685          */
2686
2687         if (!selected) {
2688                 int pages_used;
2689                 int n_blocks =
2690                     dev->internal_end_block - dev->internal_start_block + 1;
2691                 if (aggressive) {
2692                         threshold = dev->param.chunks_per_block;
2693                         iterations = n_blocks;
2694                 } else {
2695                         int max_threshold;
2696
2697                         if (background)
2698                                 max_threshold = dev->param.chunks_per_block / 2;
2699                         else
2700                                 max_threshold = dev->param.chunks_per_block / 8;
2701
2702                         if (max_threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2703                                 max_threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2704
2705                         threshold = background ? (dev->gc_not_done + 2) * 2 : 0;
2706                         if (threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2707                                 threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2708                         if (threshold > max_threshold)
2709                                 threshold = max_threshold;
2710
2711                         iterations = n_blocks / 16 + 1;
2712                         if (iterations > 100)
2713                                 iterations = 100;
2714                 }
2715
2716                 for (i = 0;
2717                      i < iterations &&
2718                      (dev->gc_dirtiest < 1 ||
2719                       dev->gc_pages_in_use > YAFFS_GC_GOOD_ENOUGH);
2720                      i++) {
2721                         dev->gc_block_finder++;
2722                         if (dev->gc_block_finder < dev->internal_start_block ||
2723                             dev->gc_block_finder > dev->internal_end_block)
2724                                 dev->gc_block_finder =
2725                                     dev->internal_start_block;
2726
2727                         bi = yaffs_get_block_info(dev, dev->gc_block_finder);
2728
2729                         pages_used = bi->pages_in_use - bi->soft_del_pages;
2730
2731                         if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2732                             pages_used < dev->param.chunks_per_block &&
2733                             (dev->gc_dirtiest < 1 ||
2734                              pages_used < dev->gc_pages_in_use) &&
2735                             yaffs_block_ok_for_gc(dev, bi)) {
2736                                 dev->gc_dirtiest = dev->gc_block_finder;
2737                                 dev->gc_pages_in_use = pages_used;
2738                         }
2739                 }
2740
2741                 if (dev->gc_dirtiest > 0 && dev->gc_pages_in_use <= threshold)
2742                         selected = dev->gc_dirtiest;
2743         }
2744
2745         /*
2746          * If nothing has been selected for a while, try the oldest dirty
2747          * because that's gumming up the works.
2748          */
2749
2750         if (!selected && dev->param.is_yaffs2 &&
2751             dev->gc_not_done >= (background ? 10 : 20)) {
2752                 yaffs2_find_oldest_dirty_seq(dev);
2753                 if (dev->oldest_dirty_block > 0) {
2754                         selected = dev->oldest_dirty_block;
2755                         dev->gc_dirtiest = selected;
2756                         dev->oldest_dirty_gc_count++;
2757                         bi = yaffs_get_block_info(dev, selected);
2758                         dev->gc_pages_in_use =
2759                             bi->pages_in_use - bi->soft_del_pages;
2760                 } else {
2761                         dev->gc_not_done = 0;
2762                 }
2763         }
2764
2765         if (selected) {
2766                 yaffs_trace(YAFFS_TRACE_GC,
2767                         "GC Selected block %d with %d free, prioritised:%d",
2768                         selected,
2769                         dev->param.chunks_per_block - dev->gc_pages_in_use,
2770                         prioritised);
2771
2772                 dev->n_gc_blocks++;
2773                 if (background)
2774                         dev->bg_gcs++;
2775
2776                 dev->gc_dirtiest = 0;
2777                 dev->gc_pages_in_use = 0;
2778                 dev->gc_not_done = 0;
2779                 if (dev->refresh_skip > 0)
2780                         dev->refresh_skip--;
2781         } else {
2782                 dev->gc_not_done++;
2783                 yaffs_trace(YAFFS_TRACE_GC,
2784                         "GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s",
2785                         dev->gc_block_finder, dev->gc_not_done, threshold,
2786                         dev->gc_dirtiest, dev->gc_pages_in_use,
2787                         dev->oldest_dirty_block, background ? " bg" : "");
2788         }
2789
2790         return selected;
2791 }
2792
2793 /* New garbage collector
2794  * If we're very low on erased blocks then we do aggressive garbage collection
2795  * otherwise we do "leasurely" garbage collection.
2796  * Aggressive gc looks further (whole array) and will accept less dirty blocks.
2797  * Passive gc only inspects smaller areas and only accepts more dirty blocks.
2798  *
2799  * The idea is to help clear out space in a more spread-out manner.
2800  * Dunno if it really does anything useful.
2801  */
2802 static int yaffs_check_gc(struct yaffs_dev *dev, int background)
2803 {
2804         int aggressive = 0;
2805         int gc_ok = YAFFS_OK;
2806         int max_tries = 0;
2807         int min_erased;
2808         int erased_chunks;
2809         int checkpt_block_adjust;
2810
2811         if (dev->param.gc_control && (dev->param.gc_control(dev) & 1) == 0)
2812                 return YAFFS_OK;
2813
2814         if (dev->gc_disable)
2815                 /* Bail out so we don't get recursive gc */
2816                 return YAFFS_OK;
2817
2818         /* This loop should pass the first time.
2819          * Only loops here if the collection does not increase space.
2820          */
2821
2822         do {
2823                 max_tries++;
2824
2825                 checkpt_block_adjust = yaffs_calc_checkpt_blocks_required(dev);
2826
2827                 min_erased =
2828                     dev->param.n_reserved_blocks + checkpt_block_adjust + 1;
2829                 erased_chunks =
2830                     dev->n_erased_blocks * dev->param.chunks_per_block;
2831
2832                 /* If we need a block soon then do aggressive gc. */
2833                 if (dev->n_erased_blocks < min_erased)
2834                         aggressive = 1;
2835                 else {
2836                         if (!background
2837                             && erased_chunks > (dev->n_free_chunks / 4))
2838                                 break;
2839
2840                         if (dev->gc_skip > 20)
2841                                 dev->gc_skip = 20;
2842                         if (erased_chunks < dev->n_free_chunks / 2 ||
2843                             dev->gc_skip < 1 || background)
2844                                 aggressive = 0;
2845                         else {
2846                                 dev->gc_skip--;
2847                                 break;
2848                         }
2849                 }
2850
2851                 dev->gc_skip = 5;
2852
2853                 /* If we don't already have a block being gc'd then see if we
2854                  * should start another */
2855
2856                 if (dev->gc_block < 1 && !aggressive) {
2857                         dev->gc_block = yaffs2_find_refresh_block(dev);
2858                         dev->gc_chunk = 0;
2859                         dev->n_clean_ups = 0;
2860                 }
2861                 if (dev->gc_block < 1) {
2862                         dev->gc_block =
2863                             yaffs_find_gc_block(dev, aggressive, background);
2864                         dev->gc_chunk = 0;
2865                         dev->n_clean_ups = 0;
2866                 }
2867
2868                 if (dev->gc_block > 0) {
2869                         dev->all_gcs++;
2870                         if (!aggressive)
2871                                 dev->passive_gc_count++;
2872
2873                         yaffs_trace(YAFFS_TRACE_GC,
2874                                 "yaffs: GC n_erased_blocks %d aggressive %d",
2875                                 dev->n_erased_blocks, aggressive);
2876
2877                         gc_ok = yaffs_gc_block(dev, dev->gc_block, aggressive);
2878                 }
2879
2880                 if (dev->n_erased_blocks < (dev->param.n_reserved_blocks) &&
2881                     dev->gc_block > 0) {
2882                         yaffs_trace(YAFFS_TRACE_GC,
2883                                 "yaffs: GC !!!no reclaim!!! n_erased_blocks %d after try %d block %d",
2884                                 dev->n_erased_blocks, max_tries,
2885                                 dev->gc_block);
2886                 }
2887         } while ((dev->n_erased_blocks < dev->param.n_reserved_blocks) &&
2888                  (dev->gc_block > 0) && (max_tries < 2));
2889
2890         return aggressive ? gc_ok : YAFFS_OK;
2891 }
2892
2893 /*
2894  * yaffs_bg_gc()
2895  * Garbage collects. Intended to be called from a background thread.
2896  * Returns non-zero if at least half the free chunks are erased.
2897  */
2898 int yaffs_bg_gc(struct yaffs_dev *dev, unsigned urgency)
2899 {
2900         int erased_chunks = dev->n_erased_blocks * dev->param.chunks_per_block;
2901
2902         yaffs_trace(YAFFS_TRACE_BACKGROUND, "Background gc %u", urgency);
2903
2904         yaffs_check_gc(dev, 1);
2905         return erased_chunks > dev->n_free_chunks / 2;
2906 }
2907
2908 /*-------------------- Data file manipulation -----------------*/
2909
2910 static int yaffs_rd_data_obj(struct yaffs_obj *in, int inode_chunk, u8 * buffer)
2911 {
2912         int nand_chunk = yaffs_find_chunk_in_file(in, inode_chunk, NULL);
2913
2914         if (nand_chunk >= 0)
2915                 return yaffs_rd_chunk_tags_nand(in->my_dev, nand_chunk,
2916                                                 buffer, NULL);
2917         else {
2918                 yaffs_trace(YAFFS_TRACE_NANDACCESS,
2919                         "Chunk %d not found zero instead",
2920                         nand_chunk);
2921                 /* get sane (zero) data if you read a hole */
2922                 memset(buffer, 0, in->my_dev->data_bytes_per_chunk);
2923                 return 0;
2924         }
2925
2926 }
2927
2928 void yaffs_chunk_del(struct yaffs_dev *dev, int chunk_id, int mark_flash,
2929                      int lyn)
2930 {
2931         int block;
2932         int page;
2933         struct yaffs_ext_tags tags;
2934         struct yaffs_block_info *bi;
2935
2936         if (chunk_id <= 0)
2937                 return;
2938
2939         dev->n_deletions++;
2940         block = chunk_id / dev->param.chunks_per_block;
2941         page = chunk_id % dev->param.chunks_per_block;
2942
2943         if (!yaffs_check_chunk_bit(dev, block, page))
2944                 yaffs_trace(YAFFS_TRACE_VERIFY,
2945                         "Deleting invalid chunk %d", chunk_id);
2946
2947         bi = yaffs_get_block_info(dev, block);
2948
2949         yaffs2_update_oldest_dirty_seq(dev, block, bi);
2950
2951         yaffs_trace(YAFFS_TRACE_DELETION,
2952                 "line %d delete of chunk %d",
2953                 lyn, chunk_id);
2954
2955         if (!dev->param.is_yaffs2 && mark_flash &&
2956             bi->block_state != YAFFS_BLOCK_STATE_COLLECTING) {
2957
2958                 memset(&tags, 0, sizeof(tags));
2959                 tags.is_deleted = 1;
2960                 yaffs_wr_chunk_tags_nand(dev, chunk_id, NULL, &tags);
2961                 yaffs_handle_chunk_update(dev, chunk_id, &tags);
2962         } else {
2963                 dev->n_unmarked_deletions++;
2964         }
2965
2966         /* Pull out of the management area.
2967          * If the whole block became dirty, this will kick off an erasure.
2968          */
2969         if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING ||
2970             bi->block_state == YAFFS_BLOCK_STATE_FULL ||
2971             bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
2972             bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
2973                 dev->n_free_chunks++;
2974                 yaffs_clear_chunk_bit(dev, block, page);
2975                 bi->pages_in_use--;
2976
2977                 if (bi->pages_in_use == 0 &&
2978                     !bi->has_shrink_hdr &&
2979                     bi->block_state != YAFFS_BLOCK_STATE_ALLOCATING &&
2980                     bi->block_state != YAFFS_BLOCK_STATE_NEEDS_SCAN) {
2981                         yaffs_block_became_dirty(dev, block);
2982                 }
2983         }
2984 }
2985
2986 static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
2987                              const u8 *buffer, int n_bytes, int use_reserve)
2988 {
2989         /* Find old chunk Need to do this to get serial number
2990          * Write new one and patch into tree.
2991          * Invalidate old tags.
2992          */
2993
2994         int prev_chunk_id;
2995         struct yaffs_ext_tags prev_tags;
2996         int new_chunk_id;
2997         struct yaffs_ext_tags new_tags;
2998         struct yaffs_dev *dev = in->my_dev;
2999
3000         yaffs_check_gc(dev, 0);
3001
3002         /* Get the previous chunk at this location in the file if it exists.
3003          * If it does not exist then put a zero into the tree. This creates
3004          * the tnode now, rather than later when it is harder to clean up.
3005          */
3006         prev_chunk_id = yaffs_find_chunk_in_file(in, inode_chunk, &prev_tags);
3007         if (prev_chunk_id < 1 &&
3008             !yaffs_put_chunk_in_file(in, inode_chunk, 0, 0))
3009                 return 0;
3010
3011         /* Set up new tags */
3012         memset(&new_tags, 0, sizeof(new_tags));
3013
3014         new_tags.chunk_id = inode_chunk;
3015         new_tags.obj_id = in->obj_id;
3016         new_tags.serial_number =
3017             (prev_chunk_id > 0) ? prev_tags.serial_number + 1 : 1;
3018         new_tags.n_bytes = n_bytes;
3019
3020         if (n_bytes < 1 || n_bytes > dev->param.total_bytes_per_chunk) {
3021                 yaffs_trace(YAFFS_TRACE_ERROR,
3022                   "Writing %d bytes to chunk!!!!!!!!!",
3023                    n_bytes);
3024                 BUG();
3025         }
3026
3027         new_chunk_id =
3028             yaffs_write_new_chunk(dev, buffer, &new_tags, use_reserve);
3029
3030         if (new_chunk_id > 0) {
3031                 yaffs_put_chunk_in_file(in, inode_chunk, new_chunk_id, 0);
3032
3033                 if (prev_chunk_id > 0)
3034                         yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
3035
3036                 yaffs_verify_file_sane(in);
3037         }
3038         return new_chunk_id;
3039
3040 }
3041
3042
3043
3044 static int yaffs_do_xattrib_mod(struct yaffs_obj *obj, int set,
3045                                 const YCHAR *name, const void *value, int size,
3046                                 int flags)
3047 {
3048         struct yaffs_xattr_mod xmod;
3049         int result;
3050
3051         xmod.set = set;
3052         xmod.name = name;
3053         xmod.data = value;
3054         xmod.size = size;
3055         xmod.flags = flags;
3056         xmod.result = -ENOSPC;
3057
3058         result = yaffs_update_oh(obj, NULL, 0, 0, 0, &xmod);
3059
3060         if (result > 0)
3061                 return xmod.result;
3062         else
3063                 return -ENOSPC;
3064 }
3065
3066 static int yaffs_apply_xattrib_mod(struct yaffs_obj *obj, char *buffer,
3067                                    struct yaffs_xattr_mod *xmod)
3068 {
3069         int retval = 0;
3070         int x_offs = sizeof(struct yaffs_obj_hdr);
3071         struct yaffs_dev *dev = obj->my_dev;
3072         int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
3073         char *x_buffer = buffer + x_offs;
3074
3075         if (xmod->set)
3076                 retval =
3077                     nval_set(x_buffer, x_size, xmod->name, xmod->data,
3078                              xmod->size, xmod->flags);
3079         else
3080                 retval = nval_del(x_buffer, x_size, xmod->name);
3081
3082         obj->has_xattr = nval_hasvalues(x_buffer, x_size);
3083         obj->xattr_known = 1;
3084         xmod->result = retval;
3085
3086         return retval;
3087 }
3088
3089 static int yaffs_do_xattrib_fetch(struct yaffs_obj *obj, const YCHAR *name,
3090                                   void *value, int size)
3091 {
3092         char *buffer = NULL;
3093         int result;
3094         struct yaffs_ext_tags tags;
3095         struct yaffs_dev *dev = obj->my_dev;
3096         int x_offs = sizeof(struct yaffs_obj_hdr);
3097         int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
3098         char *x_buffer;
3099         int retval = 0;
3100
3101         if (obj->hdr_chunk < 1)
3102                 return -ENODATA;
3103
3104         /* If we know that the object has no xattribs then don't do all the
3105          * reading and parsing.
3106          */
3107         if (obj->xattr_known && !obj->has_xattr) {
3108                 if (name)
3109                         return -ENODATA;
3110                 else
3111                         return 0;
3112         }
3113
3114         buffer = (char *)yaffs_get_temp_buffer(dev);
3115         if (!buffer)
3116                 return -ENOMEM;
3117
3118         result =
3119             yaffs_rd_chunk_tags_nand(dev, obj->hdr_chunk, (u8 *) buffer, &tags);
3120
3121         if (result != YAFFS_OK)
3122                 retval = -ENOENT;
3123         else {
3124                 x_buffer = buffer + x_offs;
3125
3126                 if (!obj->xattr_known) {
3127                         obj->has_xattr = nval_hasvalues(x_buffer, x_size);
3128                         obj->xattr_known = 1;
3129                 }
3130
3131                 if (name)
3132                         retval = nval_get(x_buffer, x_size, name, value, size);
3133                 else
3134                         retval = nval_list(x_buffer, x_size, value, size);
3135         }
3136         yaffs_release_temp_buffer(dev, (u8 *) buffer);
3137         return retval;
3138 }
3139
3140 int yaffs_set_xattrib(struct yaffs_obj *obj, const YCHAR * name,
3141                       const void *value, int size, int flags)
3142 {
3143         return yaffs_do_xattrib_mod(obj, 1, name, value, size, flags);
3144 }
3145
3146 int yaffs_remove_xattrib(struct yaffs_obj *obj, const YCHAR * name)
3147 {
3148         return yaffs_do_xattrib_mod(obj, 0, name, NULL, 0, 0);
3149 }
3150
3151 int yaffs_get_xattrib(struct yaffs_obj *obj, const YCHAR * name, void *value,
3152                       int size)
3153 {
3154         return yaffs_do_xattrib_fetch(obj, name, value, size);
3155 }
3156
3157 int yaffs_list_xattrib(struct yaffs_obj *obj, char *buffer, int size)
3158 {
3159         return yaffs_do_xattrib_fetch(obj, NULL, buffer, size);
3160 }
3161
3162 static void yaffs_check_obj_details_loaded(struct yaffs_obj *in)
3163 {
3164         u8 *buf;
3165         struct yaffs_obj_hdr *oh;
3166         struct yaffs_dev *dev;
3167         struct yaffs_ext_tags tags;
3168         int result;
3169         int alloc_failed = 0;
3170
3171         if (!in || !in->lazy_loaded || in->hdr_chunk < 1)
3172                 return;
3173
3174         dev = in->my_dev;
3175         in->lazy_loaded = 0;
3176         buf = yaffs_get_temp_buffer(dev);
3177
3178         result = yaffs_rd_chunk_tags_nand(dev, in->hdr_chunk, buf, &tags);
3179         oh = (struct yaffs_obj_hdr *)buf;
3180
3181         in->yst_mode = oh->yst_mode;
3182         yaffs_load_attribs(in, oh);
3183         yaffs_set_obj_name_from_oh(in, oh);
3184
3185         if (in->variant_type == YAFFS_OBJECT_TYPE_SYMLINK) {
3186                 in->variant.symlink_variant.alias =
3187                     yaffs_clone_str(oh->alias);
3188                 if (!in->variant.symlink_variant.alias)
3189                         alloc_failed = 1;       /* Not returned */
3190         }
3191         yaffs_release_temp_buffer(dev, buf);
3192 }
3193
3194 static void yaffs_load_name_from_oh(struct yaffs_dev *dev, YCHAR *name,
3195                                     const YCHAR *oh_name, int buff_size)
3196 {
3197 #ifdef CONFIG_YAFFS_AUTO_UNICODE
3198         if (dev->param.auto_unicode) {
3199                 if (*oh_name) {
3200                         /* It is an ASCII name, do an ASCII to
3201                          * unicode conversion */
3202                         const char *ascii_oh_name = (const char *)oh_name;
3203                         int n = buff_size - 1;
3204                         while (n > 0 && *ascii_oh_name) {
3205                                 *name = *ascii_oh_name;
3206                                 name++;
3207                                 ascii_oh_name++;
3208                                 n--;
3209                         }
3210                 } else {
3211                         strncpy(name, oh_name + 1, buff_size - 1);
3212                 }
3213         } else {
3214 #else
3215         {
3216 #endif
3217                 strncpy(name, oh_name, buff_size - 1);
3218         }
3219 }
3220
3221 static void yaffs_load_oh_from_name(struct yaffs_dev *dev, YCHAR *oh_name,
3222                                     const YCHAR *name)
3223 {
3224 #ifdef CONFIG_YAFFS_AUTO_UNICODE
3225
3226         int is_ascii;
3227         YCHAR *w;
3228
3229         if (dev->param.auto_unicode) {
3230
3231                 is_ascii = 1;
3232                 w = name;
3233
3234                 /* Figure out if the name will fit in ascii character set */
3235                 while (is_ascii && *w) {
3236                         if ((*w) & 0xff00)
3237                                 is_ascii = 0;
3238                         w++;
3239                 }
3240
3241                 if (is_ascii) {
3242                         /* It is an ASCII name, so convert unicode to ascii */
3243                         char *ascii_oh_name = (char *)oh_name;
3244                         int n = YAFFS_MAX_NAME_LENGTH - 1;
3245                         while (n > 0 && *name) {
3246                                 *ascii_oh_name = *name;
3247                                 name++;
3248                                 ascii_oh_name++;
3249                                 n--;
3250                         }
3251                 } else {
3252                         /* Unicode name, so save starting at the second YCHAR */
3253                         *oh_name = 0;
3254                         strncpy(oh_name + 1, name, YAFFS_MAX_NAME_LENGTH - 2);
3255                 }
3256         } else {
3257 #else
3258         {
3259 #endif
3260                 strncpy(oh_name, name, YAFFS_MAX_NAME_LENGTH - 1);
3261         }
3262 }
3263
3264 /* UpdateObjectHeader updates the header on NAND for an object.
3265  * If name is not NULL, then that new name is used.
3266  */
3267 int yaffs_update_oh(struct yaffs_obj *in, const YCHAR *name, int force,
3268                     int is_shrink, int shadows, struct yaffs_xattr_mod *xmod)
3269 {
3270
3271         struct yaffs_block_info *bi;
3272         struct yaffs_dev *dev = in->my_dev;
3273         int prev_chunk_id;
3274         int ret_val = 0;
3275         int result = 0;
3276         int new_chunk_id;
3277         struct yaffs_ext_tags new_tags;
3278         struct yaffs_ext_tags old_tags;
3279         const YCHAR *alias = NULL;
3280         u8 *buffer = NULL;
3281         YCHAR old_name[YAFFS_MAX_NAME_LENGTH + 1];
3282         struct yaffs_obj_hdr *oh = NULL;
3283
3284         strcpy(old_name, _Y("silly old name"));
3285
3286         if (in->fake && in != dev->root_dir && !force && !xmod)
3287                 return ret_val;
3288
3289         yaffs_check_gc(dev, 0);
3290         yaffs_check_obj_details_loaded(in);
3291
3292         buffer = yaffs_get_temp_buffer(in->my_dev);
3293         oh = (struct yaffs_obj_hdr *)buffer;
3294
3295         prev_chunk_id = in->hdr_chunk;
3296
3297         if (prev_chunk_id > 0) {
3298                 result = yaffs_rd_chunk_tags_nand(dev, prev_chunk_id,
3299                                                   buffer, &old_tags);
3300
3301                 yaffs_verify_oh(in, oh, &old_tags, 0);
3302                 memcpy(old_name, oh->name, sizeof(oh->name));
3303                 memset(buffer, 0xff, sizeof(struct yaffs_obj_hdr));
3304         } else {
3305                 memset(buffer, 0xff, dev->data_bytes_per_chunk);
3306         }
3307
3308         oh->type = in->variant_type;
3309         oh->yst_mode = in->yst_mode;
3310         oh->shadows_obj = oh->inband_shadowed_obj_id = shadows;
3311
3312         yaffs_load_attribs_oh(oh, in);
3313
3314         if (in->parent)
3315                 oh->parent_obj_id = in->parent->obj_id;
3316         else
3317                 oh->parent_obj_id = 0;
3318
3319         if (name && *name) {
3320                 memset(oh->name, 0, sizeof(oh->name));
3321                 yaffs_load_oh_from_name(dev, oh->name, name);
3322         } else if (prev_chunk_id > 0) {
3323                 memcpy(oh->name, old_name, sizeof(oh->name));
3324         } else {
3325                 memset(oh->name, 0, sizeof(oh->name));
3326         }
3327
3328         oh->is_shrink = is_shrink;
3329
3330         switch (in->variant_type) {
3331         case YAFFS_OBJECT_TYPE_UNKNOWN:
3332                 /* Should not happen */
3333                 break;
3334         case YAFFS_OBJECT_TYPE_FILE:
3335                 oh->file_size =
3336                     (oh->parent_obj_id == YAFFS_OBJECTID_DELETED ||
3337                      oh->parent_obj_id == YAFFS_OBJECTID_UNLINKED) ?
3338                      0 : in->variant.file_variant.file_size;
3339                 break;
3340         case YAFFS_OBJECT_TYPE_HARDLINK:
3341                 oh->equiv_id = in->variant.hardlink_variant.equiv_id;
3342                 break;
3343         case YAFFS_OBJECT_TYPE_SPECIAL:
3344                 /* Do nothing */
3345                 break;
3346         case YAFFS_OBJECT_TYPE_DIRECTORY:
3347                 /* Do nothing */
3348                 break;
3349         case YAFFS_OBJECT_TYPE_SYMLINK:
3350                 alias = in->variant.symlink_variant.alias;
3351                 if (!alias)
3352                         alias = _Y("no alias");
3353                 strncpy(oh->alias, alias, YAFFS_MAX_ALIAS_LENGTH);
3354                 oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
3355                 break;
3356         }
3357
3358         /* process any xattrib modifications */
3359         if (xmod)
3360                 yaffs_apply_xattrib_mod(in, (char *)buffer, xmod);
3361
3362         /* Tags */
3363         memset(&new_tags, 0, sizeof(new_tags));
3364         in->serial++;
3365         new_tags.chunk_id = 0;
3366         new_tags.obj_id = in->obj_id;
3367         new_tags.serial_number = in->serial;
3368
3369         /* Add extra info for file header */
3370         new_tags.extra_available = 1;
3371         new_tags.extra_parent_id = oh->parent_obj_id;
3372         new_tags.extra_length = oh->file_size;
3373         new_tags.extra_is_shrink = oh->is_shrink;
3374         new_tags.extra_equiv_id = oh->equiv_id;
3375         new_tags.extra_shadows = (oh->shadows_obj > 0) ? 1 : 0;
3376         new_tags.extra_obj_type = in->variant_type;
3377         yaffs_verify_oh(in, oh, &new_tags, 1);
3378
3379         /* Create new chunk in NAND */
3380         new_chunk_id =
3381             yaffs_write_new_chunk(dev, buffer, &new_tags,
3382                                   (prev_chunk_id > 0) ? 1 : 0);
3383
3384         if (buffer)
3385                 yaffs_release_temp_buffer(dev, buffer);
3386
3387         if (new_chunk_id < 0)
3388                 return new_chunk_id;
3389
3390         in->hdr_chunk = new_chunk_id;
3391
3392         if (prev_chunk_id > 0)
3393                 yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
3394
3395         if (!yaffs_obj_cache_dirty(in))
3396                 in->dirty = 0;
3397
3398         /* If this was a shrink, then mark the block
3399          * that the chunk lives on */
3400         if (is_shrink) {
3401                 bi = yaffs_get_block_info(in->my_dev,
3402                                           new_chunk_id /
3403                                           in->my_dev->param.chunks_per_block);
3404                 bi->has_shrink_hdr = 1;
3405         }
3406
3407
3408         return new_chunk_id;
3409 }
3410
3411 /*--------------------- File read/write ------------------------
3412  * Read and write have very similar structures.
3413  * In general the read/write has three parts to it
3414  * An incomplete chunk to start with (if the read/write is not chunk-aligned)
3415  * Some complete chunks
3416  * An incomplete chunk to end off with
3417  *
3418  * Curve-balls: the first chunk might also be the last chunk.
3419  */
3420
3421 int yaffs_file_rd(struct yaffs_obj *in, u8 * buffer, loff_t offset, int n_bytes)
3422 {
3423         int chunk;
3424         u32 start;
3425         int n_copy;
3426         int n