yaffs direct: Fix error for attempting to rename over a non-empty directory
[yaffs2.git] / yaffs_guts.c
1 /*
2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
3  *
4  * Copyright (C) 2002-2010 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_tagsvalidity.h"
19 #include "yaffs_getblockinfo.h"
20
21 #include "yaffs_tagscompat.h"
22
23 #include "yaffs_nand.h"
24
25 #include "yaffs_yaffs1.h"
26 #include "yaffs_yaffs2.h"
27 #include "yaffs_bitmap.h"
28 #include "yaffs_verify.h"
29
30 #include "yaffs_nand.h"
31 #include "yaffs_packedtags2.h"
32
33 #include "yaffs_nameval.h"
34 #include "yaffs_allocator.h"
35
36 #include "yaffs_attribs.h"
37
38 /* Note YAFFS_GC_GOOD_ENOUGH must be <= YAFFS_GC_PASSIVE_THRESHOLD */
39 #define YAFFS_GC_GOOD_ENOUGH 2
40 #define YAFFS_GC_PASSIVE_THRESHOLD 4
41
42 #include "yaffs_ecc.h"
43
44 /* Robustification (if it ever comes about...) */
45 static void yaffs_retire_block(struct yaffs_dev *dev, int flash_block);
46 static void yaffs_handle_chunk_wr_error(struct yaffs_dev *dev, int nand_chunk,
47                                         int erased_ok);
48 static void yaffs_handle_chunk_wr_ok(struct yaffs_dev *dev, int nand_chunk,
49                                      const u8 * data,
50                                      const struct yaffs_ext_tags *tags);
51 static void yaffs_handle_chunk_update(struct yaffs_dev *dev, int nand_chunk,
52                                       const struct yaffs_ext_tags *tags);
53
54 /* Other local prototypes */
55 static void yaffs_update_parent(struct yaffs_obj *obj);
56 static int yaffs_unlink_obj(struct yaffs_obj *obj);
57 static int yaffs_obj_cache_dirty(struct yaffs_obj *obj);
58
59 static int yaffs_write_new_chunk(struct yaffs_dev *dev,
60                                  const u8 * buffer,
61                                  struct yaffs_ext_tags *tags, int use_reserver);
62
63 static struct yaffs_obj *yaffs_new_obj(struct yaffs_dev *dev, int number,
64                                        enum yaffs_obj_type type);
65
66 static int yaffs_apply_xattrib_mod(struct yaffs_obj *obj, char *buffer,
67                                    struct yaffs_xattr_mod *xmod);
68
69 static void yaffs_remove_obj_from_dir(struct yaffs_obj *obj);
70 static int yaffs_generic_obj_del(struct yaffs_obj *in);
71
72 static int yaffs_check_chunk_erased(struct yaffs_dev *dev, int nand_chunk);
73
74 static int yaffs_unlink_worker(struct yaffs_obj *obj);
75
76 static int yaffs_tags_match(const struct yaffs_ext_tags *tags, int obj_id,
77                             int chunk_obj);
78
79 static int yaffs_alloc_chunk(struct yaffs_dev *dev, int use_reserver,
80                              struct yaffs_block_info **block_ptr);
81
82 static void yaffs_check_obj_details_loaded(struct yaffs_obj *in);
83
84 static void yaffs_invalidate_whole_cache(struct yaffs_obj *in);
85 static void yaffs_invalidate_chunk_cache(struct yaffs_obj *object,
86                                          int chunk_id);
87
88 static int yaffs_find_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
89                                     struct yaffs_ext_tags *tags);
90
91 static int yaffs_verify_chunk_written(struct yaffs_dev *dev,
92                                       int nand_chunk,
93                                       const u8 * data,
94                                       struct yaffs_ext_tags *tags);
95
96 static void yaffs_load_name_from_oh(struct yaffs_dev *dev, YCHAR * name,
97                                     const YCHAR * oh_name, int buff_size);
98 static void yaffs_load_oh_from_name(struct yaffs_dev *dev, YCHAR * oh_name,
99                                     const YCHAR * name);
100
101 /* Function to calculate chunk and offset */
102
103 static void yaffs_addr_to_chunk(struct yaffs_dev *dev, loff_t addr,
104                                 int *chunk_out, u32 * offset_out)
105 {
106         int chunk;
107         u32 offset;
108
109         chunk = (u32) (addr >> dev->chunk_shift);
110
111         if (dev->chunk_div == 1) {
112                 /* easy power of 2 case */
113                 offset = (u32) (addr & dev->chunk_mask);
114         } else {
115                 /* Non power-of-2 case */
116
117                 loff_t chunk_base;
118
119                 chunk /= dev->chunk_div;
120
121                 chunk_base = ((loff_t) chunk) * dev->data_bytes_per_chunk;
122                 offset = (u32) (addr - chunk_base);
123         }
124
125         *chunk_out = chunk;
126         *offset_out = offset;
127 }
128
129 /* Function to return the number of shifts for a power of 2 greater than or
130  * equal to the given number
131  * Note we don't try to cater for all possible numbers and this does not have to
132  * be hellishly efficient.
133  */
134
135 static u32 calc_shifts_ceiling(u32 x)
136 {
137         int extra_bits;
138         int shifts;
139
140         shifts = extra_bits = 0;
141
142         while (x > 1) {
143                 if (x & 1)
144                         extra_bits++;
145                 x >>= 1;
146                 shifts++;
147         }
148
149         if (extra_bits)
150                 shifts++;
151
152         return shifts;
153 }
154
155 /* Function to return the number of shifts to get a 1 in bit 0
156  */
157
158 static u32 calc_shifts(u32 x)
159 {
160         u32 shifts;
161
162         shifts = 0;
163
164         if (!x)
165                 return 0;
166
167         while (!(x & 1)) {
168                 x >>= 1;
169                 shifts++;
170         }
171
172         return shifts;
173 }
174
175 /*
176  * Temporary buffer manipulations.
177  */
178
179 static int yaffs_init_tmp_buffers(struct yaffs_dev *dev)
180 {
181         int i;
182         u8 *buf = (u8 *) 1;
183
184         memset(dev->temp_buffer, 0, sizeof(dev->temp_buffer));
185
186         for (i = 0; buf && i < YAFFS_N_TEMP_BUFFERS; i++) {
187                 dev->temp_buffer[i].line = 0;   /* not in use */
188                 dev->temp_buffer[i].buffer = buf =
189                     YMALLOC_DMA(dev->param.total_bytes_per_chunk);
190         }
191
192         return buf ? YAFFS_OK : YAFFS_FAIL;
193 }
194
195 u8 *yaffs_get_temp_buffer(struct yaffs_dev * dev, int line_no)
196 {
197         int i, j;
198
199         dev->temp_in_use++;
200         if (dev->temp_in_use > dev->max_temp)
201                 dev->max_temp = dev->temp_in_use;
202
203         for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
204                 if (dev->temp_buffer[i].line == 0) {
205                         dev->temp_buffer[i].line = line_no;
206                         if ((i + 1) > dev->max_temp) {
207                                 dev->max_temp = i + 1;
208                                 for (j = 0; j <= i; j++)
209                                         dev->temp_buffer[j].max_line =
210                                             dev->temp_buffer[j].line;
211                         }
212
213                         return dev->temp_buffer[i].buffer;
214                 }
215         }
216
217         T(YAFFS_TRACE_BUFFERS,
218           (TSTR("Out of temp buffers at line %d, other held by lines:"),
219            line_no));
220         for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++)
221                 T(YAFFS_TRACE_BUFFERS,
222                   (TSTR(" %d "), dev->temp_buffer[i].line));
223
224         T(YAFFS_TRACE_BUFFERS, (TSTR(" " TENDSTR)));
225
226         /*
227          * If we got here then we have to allocate an unmanaged one
228          * This is not good.
229          */
230
231         dev->unmanaged_buffer_allocs++;
232         return YMALLOC(dev->data_bytes_per_chunk);
233
234 }
235
236 void yaffs_release_temp_buffer(struct yaffs_dev *dev, u8 * buffer, int line_no)
237 {
238         int i;
239
240         dev->temp_in_use--;
241
242         for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
243                 if (dev->temp_buffer[i].buffer == buffer) {
244                         dev->temp_buffer[i].line = 0;
245                         return;
246                 }
247         }
248
249         if (buffer) {
250                 /* assume it is an unmanaged one. */
251                 T(YAFFS_TRACE_BUFFERS,
252                   (TSTR("Releasing unmanaged temp buffer in line %d" TENDSTR),
253                    line_no));
254                 YFREE(buffer);
255                 dev->unmanaged_buffer_deallocs++;
256         }
257
258 }
259
260 /*
261  * Determine if we have a managed buffer.
262  */
263 int yaffs_is_managed_tmp_buffer(struct yaffs_dev *dev, const u8 * buffer)
264 {
265         int i;
266
267         for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
268                 if (dev->temp_buffer[i].buffer == buffer)
269                         return 1;
270         }
271
272         for (i = 0; i < dev->param.n_caches; i++) {
273                 if (dev->cache[i].data == buffer)
274                         return 1;
275         }
276
277         if (buffer == dev->checkpt_buffer)
278                 return 1;
279
280         T(YAFFS_TRACE_ALWAYS,
281           (TSTR("yaffs: unmaged buffer detected.\n" TENDSTR)));
282         return 0;
283 }
284
285 /*
286  * Verification code
287  */
288
289 /*
290  *  Simple hash function. Needs to have a reasonable spread
291  */
292
293 static Y_INLINE int yaffs_hash_fn(int n)
294 {
295         n = abs(n);
296         return n % YAFFS_NOBJECT_BUCKETS;
297 }
298
299 /*
300  * Access functions to useful fake objects.
301  * Note that root might have a presence in NAND if permissions are set.
302  */
303
304 struct yaffs_obj *yaffs_root(struct yaffs_dev *dev)
305 {
306         return dev->root_dir;
307 }
308
309 struct yaffs_obj *yaffs_lost_n_found(struct yaffs_dev *dev)
310 {
311         return dev->lost_n_found;
312 }
313
314 /*
315  *  Erased NAND checking functions
316  */
317
318 int yaffs_check_ff(u8 * buffer, int n_bytes)
319 {
320         /* Horrible, slow implementation */
321         while (n_bytes--) {
322                 if (*buffer != 0xFF)
323                         return 0;
324                 buffer++;
325         }
326         return 1;
327 }
328
329 static int yaffs_check_chunk_erased(struct yaffs_dev *dev, int nand_chunk)
330 {
331         int retval = YAFFS_OK;
332         u8 *data = yaffs_get_temp_buffer(dev, __LINE__);
333         struct yaffs_ext_tags tags;
334         int result;
335
336         result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, data, &tags);
337
338         if (tags.ecc_result > YAFFS_ECC_RESULT_NO_ERROR)
339                 retval = YAFFS_FAIL;
340
341         if (!yaffs_check_ff(data, dev->data_bytes_per_chunk) || tags.chunk_used) {
342                 T(YAFFS_TRACE_NANDACCESS,
343                   (TSTR("Chunk %d not erased" TENDSTR), nand_chunk));
344                 retval = YAFFS_FAIL;
345         }
346
347         yaffs_release_temp_buffer(dev, data, __LINE__);
348
349         return retval;
350
351 }
352
353 static int yaffs_verify_chunk_written(struct yaffs_dev *dev,
354                                       int nand_chunk,
355                                       const u8 * data,
356                                       struct yaffs_ext_tags *tags)
357 {
358         int retval = YAFFS_OK;
359         struct yaffs_ext_tags temp_tags;
360         u8 *buffer = yaffs_get_temp_buffer(dev, __LINE__);
361         int result;
362
363         result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, buffer, &temp_tags);
364         if (memcmp(buffer, data, dev->data_bytes_per_chunk) ||
365             temp_tags.obj_id != tags->obj_id ||
366             temp_tags.chunk_id != tags->chunk_id ||
367             temp_tags.n_bytes != tags->n_bytes)
368                 retval = YAFFS_FAIL;
369
370         yaffs_release_temp_buffer(dev, buffer, __LINE__);
371
372         return retval;
373 }
374
375 static int yaffs_write_new_chunk(struct yaffs_dev *dev,
376                                  const u8 * data,
377                                  struct yaffs_ext_tags *tags, int use_reserver)
378 {
379         int attempts = 0;
380         int write_ok = 0;
381         int chunk;
382
383         yaffs2_checkpt_invalidate(dev);
384
385         do {
386                 struct yaffs_block_info *bi = 0;
387                 int erased_ok = 0;
388
389                 chunk = yaffs_alloc_chunk(dev, use_reserver, &bi);
390                 if (chunk < 0) {
391                         /* no space */
392                         break;
393                 }
394
395                 /* First check this chunk is erased, if it needs
396                  * checking.  The checking policy (unless forced
397                  * always on) is as follows:
398                  *
399                  * Check the first page we try to write in a block.
400                  * If the check passes then we don't need to check any
401                  * more.        If the check fails, we check again...
402                  * If the block has been erased, we don't need to check.
403                  *
404                  * However, if the block has been prioritised for gc,
405                  * then we think there might be something odd about
406                  * this block and stop using it.
407                  *
408                  * Rationale: We should only ever see chunks that have
409                  * not been erased if there was a partially written
410                  * chunk due to power loss.  This checking policy should
411                  * catch that case with very few checks and thus save a
412                  * lot of checks that are most likely not needed.
413                  *
414                  * Mods to the above
415                  * If an erase check fails or the write fails we skip the 
416                  * rest of the block.
417                  */
418
419                 /* let's give it a try */
420                 attempts++;
421
422                 if (dev->param.always_check_erased)
423                         bi->skip_erased_check = 0;
424
425                 if (!bi->skip_erased_check) {
426                         erased_ok = yaffs_check_chunk_erased(dev, chunk);
427                         if (erased_ok != YAFFS_OK) {
428                                 T(YAFFS_TRACE_ERROR,
429                                   (TSTR("**>> yaffs chunk %d was not erased"
430                                         TENDSTR), chunk));
431
432                                 /* If not erased, delete this one,
433                                  * skip rest of block and
434                                  * try another chunk */
435                                 yaffs_chunk_del(dev, chunk, 1, __LINE__);
436                                 yaffs_skip_rest_of_block(dev);
437                                 continue;
438                         }
439                 }
440
441                 write_ok = yaffs_wr_chunk_tags_nand(dev, chunk, data, tags);
442
443                 if (!bi->skip_erased_check)
444                         write_ok =
445                             yaffs_verify_chunk_written(dev, chunk, data, tags);
446
447                 if (write_ok != YAFFS_OK) {
448                         /* Clean up aborted write, skip to next block and
449                          * try another chunk */
450                         yaffs_handle_chunk_wr_error(dev, chunk, erased_ok);
451                         continue;
452                 }
453
454                 bi->skip_erased_check = 1;
455
456                 /* Copy the data into the robustification buffer */
457                 yaffs_handle_chunk_wr_ok(dev, chunk, data, tags);
458
459         } while (write_ok != YAFFS_OK &&
460                  (yaffs_wr_attempts <= 0 || attempts <= yaffs_wr_attempts));
461
462         if (!write_ok)
463                 chunk = -1;
464
465         if (attempts > 1) {
466                 T(YAFFS_TRACE_ERROR,
467                   (TSTR("**>> yaffs write required %d attempts" TENDSTR),
468                    attempts));
469
470                 dev->n_retired_writes += (attempts - 1);
471         }
472
473         return chunk;
474 }
475
476 /*
477  * Block retiring for handling a broken block.
478  */
479
480 static void yaffs_retire_block(struct yaffs_dev *dev, int flash_block)
481 {
482         struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);
483
484         yaffs2_checkpt_invalidate(dev);
485
486         yaffs2_clear_oldest_dirty_seq(dev, bi);
487
488         if (yaffs_mark_bad(dev, flash_block) != YAFFS_OK) {
489                 if (yaffs_erase_block(dev, flash_block) != YAFFS_OK) {
490                         T(YAFFS_TRACE_ALWAYS,
491                           (TSTR
492                            ("yaffs: Failed to mark bad and erase block %d"
493                             TENDSTR), flash_block));
494                 } else {
495                         struct yaffs_ext_tags tags;
496                         int chunk_id =
497                             flash_block * dev->param.chunks_per_block;
498
499                         u8 *buffer = yaffs_get_temp_buffer(dev, __LINE__);
500
501                         memset(buffer, 0xff, dev->data_bytes_per_chunk);
502                         yaffs_init_tags(&tags);
503                         tags.seq_number = YAFFS_SEQUENCE_BAD_BLOCK;
504                         if (dev->param.write_chunk_tags_fn(dev, chunk_id -
505                                                            dev->chunk_offset,
506                                                            buffer,
507                                                            &tags) != YAFFS_OK)
508                                 T(YAFFS_TRACE_ALWAYS,
509                                   (TSTR
510                                    ("yaffs: Failed to "
511                                     TCONT("write bad block marker to block %d")
512                                     TENDSTR), flash_block));
513
514                         yaffs_release_temp_buffer(dev, buffer, __LINE__);
515                 }
516         }
517
518         bi->block_state = YAFFS_BLOCK_STATE_DEAD;
519         bi->gc_prioritise = 0;
520         bi->needs_retiring = 0;
521
522         dev->n_retired_blocks++;
523 }
524
525 /*
526  * Functions for robustisizing TODO
527  *
528  */
529
530 static void yaffs_handle_chunk_wr_ok(struct yaffs_dev *dev, int nand_chunk,
531                                      const u8 * data,
532                                      const struct yaffs_ext_tags *tags)
533 {
534         dev = dev;
535         nand_chunk = nand_chunk;
536         data = data;
537         tags = tags;
538 }
539
540 static void yaffs_handle_chunk_update(struct yaffs_dev *dev, int nand_chunk,
541                                       const struct yaffs_ext_tags *tags)
542 {
543         dev = dev;
544         nand_chunk = nand_chunk;
545         tags = tags;
546 }
547
548 void yaffs_handle_chunk_error(struct yaffs_dev *dev,
549                               struct yaffs_block_info *bi)
550 {
551         if (!bi->gc_prioritise) {
552                 bi->gc_prioritise = 1;
553                 dev->has_pending_prioritised_gc = 1;
554                 bi->chunk_error_strikes++;
555
556                 if (bi->chunk_error_strikes > 3) {
557                         bi->needs_retiring = 1; /* Too many stikes, so retire this */
558                         T(YAFFS_TRACE_ALWAYS,
559                           (TSTR("yaffs: Block struck out" TENDSTR)));
560
561                 }
562         }
563 }
564
565 static void yaffs_handle_chunk_wr_error(struct yaffs_dev *dev, int nand_chunk,
566                                         int erased_ok)
567 {
568         int flash_block = nand_chunk / dev->param.chunks_per_block;
569         struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);
570
571         yaffs_handle_chunk_error(dev, bi);
572
573         if (erased_ok) {
574                 /* Was an actual write failure, so mark the block for retirement  */
575                 bi->needs_retiring = 1;
576                 T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
577                   (TSTR("**>> Block %d needs retiring" TENDSTR), flash_block));
578         }
579
580         /* Delete the chunk */
581         yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
582         yaffs_skip_rest_of_block(dev);
583 }
584
585 /*---------------- Name handling functions ------------*/
586
587 static u16 yaffs_calc_name_sum(const YCHAR * name)
588 {
589         u16 sum = 0;
590         u16 i = 1;
591
592         const YUCHAR *bname = (const YUCHAR *)name;
593         if (bname) {
594                 while ((*bname) && (i < (YAFFS_MAX_NAME_LENGTH / 2))) {
595
596                         /* 0x1f mask is case insensitive */
597                         sum += ((*bname) & 0x1f) * i;
598                         i++;
599                         bname++;
600                 }
601         }
602         return sum;
603 }
604
605 void yaffs_set_obj_name(struct yaffs_obj *obj, const YCHAR * name)
606 {
607 #ifndef CONFIG_YAFFS_NO_SHORT_NAMES
608         memset(obj->short_name, 0, sizeof(obj->short_name));
609         if (name && 
610                 yaffs_strnlen(name, YAFFS_SHORT_NAME_LENGTH + 1) <=
611             YAFFS_SHORT_NAME_LENGTH)
612                 yaffs_strcpy(obj->short_name, name);
613         else
614                 obj->short_name[0] = _Y('\0');
615 #endif
616         obj->sum = yaffs_calc_name_sum(name);
617 }
618
619 void yaffs_set_obj_name_from_oh(struct yaffs_obj *obj,
620                                 const struct yaffs_obj_hdr *oh)
621 {
622 #ifdef CONFIG_YAFFS_AUTO_UNICODE
623         YCHAR tmp_name[YAFFS_MAX_NAME_LENGTH + 1];
624         memset(tmp_name, 0, sizeof(tmp_name));
625         yaffs_load_name_from_oh(obj->my_dev, tmp_name, oh->name,
626                                 YAFFS_MAX_NAME_LENGTH + 1);
627         yaffs_set_obj_name(obj, tmp_name);
628 #else
629         yaffs_set_obj_name(obj, oh->name);
630 #endif
631 }
632
633 /*-------------------- TNODES -------------------
634
635  * List of spare tnodes
636  * The list is hooked together using the first pointer
637  * in the tnode.
638  */
639
640 struct yaffs_tnode *yaffs_get_tnode(struct yaffs_dev *dev)
641 {
642         struct yaffs_tnode *tn = yaffs_alloc_raw_tnode(dev);
643         if (tn) {
644                 memset(tn, 0, dev->tnode_size);
645                 dev->n_tnodes++;
646         }
647
648         dev->checkpoint_blocks_required = 0;    /* force recalculation */
649
650         return tn;
651 }
652
653 /* FreeTnode frees up a tnode and puts it back on the free list */
654 static void yaffs_free_tnode(struct yaffs_dev *dev, struct yaffs_tnode *tn)
655 {
656         yaffs_free_raw_tnode(dev, tn);
657         dev->n_tnodes--;
658         dev->checkpoint_blocks_required = 0;    /* force recalculation */
659 }
660
661 static void yaffs_deinit_tnodes_and_objs(struct yaffs_dev *dev)
662 {
663         yaffs_deinit_raw_tnodes_and_objs(dev);
664         dev->n_obj = 0;
665         dev->n_tnodes = 0;
666 }
667
668 void yaffs_load_tnode_0(struct yaffs_dev *dev, struct yaffs_tnode *tn,
669                         unsigned pos, unsigned val)
670 {
671         u32 *map = (u32 *) tn;
672         u32 bit_in_map;
673         u32 bit_in_word;
674         u32 word_in_map;
675         u32 mask;
676
677         pos &= YAFFS_TNODES_LEVEL0_MASK;
678         val >>= dev->chunk_grp_bits;
679
680         bit_in_map = pos * dev->tnode_width;
681         word_in_map = bit_in_map / 32;
682         bit_in_word = bit_in_map & (32 - 1);
683
684         mask = dev->tnode_mask << bit_in_word;
685
686         map[word_in_map] &= ~mask;
687         map[word_in_map] |= (mask & (val << bit_in_word));
688
689         if (dev->tnode_width > (32 - bit_in_word)) {
690                 bit_in_word = (32 - bit_in_word);
691                 word_in_map++;;
692                 mask =
693                     dev->tnode_mask >> ( /*dev->tnode_width - */ bit_in_word);
694                 map[word_in_map] &= ~mask;
695                 map[word_in_map] |= (mask & (val >> bit_in_word));
696         }
697 }
698
699 u32 yaffs_get_group_base(struct yaffs_dev *dev, struct yaffs_tnode *tn,
700                          unsigned pos)
701 {
702         u32 *map = (u32 *) tn;
703         u32 bit_in_map;
704         u32 bit_in_word;
705         u32 word_in_map;
706         u32 val;
707
708         pos &= YAFFS_TNODES_LEVEL0_MASK;
709
710         bit_in_map = pos * dev->tnode_width;
711         word_in_map = bit_in_map / 32;
712         bit_in_word = bit_in_map & (32 - 1);
713
714         val = map[word_in_map] >> bit_in_word;
715
716         if (dev->tnode_width > (32 - bit_in_word)) {
717                 bit_in_word = (32 - bit_in_word);
718                 word_in_map++;;
719                 val |= (map[word_in_map] << bit_in_word);
720         }
721
722         val &= dev->tnode_mask;
723         val <<= dev->chunk_grp_bits;
724
725         return val;
726 }
727
728 /* ------------------- End of individual tnode manipulation -----------------*/
729
730 /* ---------Functions to manipulate the look-up tree (made up of tnodes) ------
731  * The look up tree is represented by the top tnode and the number of top_level
732  * in the tree. 0 means only the level 0 tnode is in the tree.
733  */
734
735 /* FindLevel0Tnode finds the level 0 tnode, if one exists. */
736 struct yaffs_tnode *yaffs_find_tnode_0(struct yaffs_dev *dev,
737                                        struct yaffs_file_var *file_struct,
738                                        u32 chunk_id)
739 {
740         struct yaffs_tnode *tn = file_struct->top;
741         u32 i;
742         int required_depth;
743         int level = file_struct->top_level;
744
745         dev = dev;
746
747         /* Check sane level and chunk Id */
748         if (level < 0 || level > YAFFS_TNODES_MAX_LEVEL)
749                 return NULL;
750
751         if (chunk_id > YAFFS_MAX_CHUNK_ID)
752                 return NULL;
753
754         /* First check we're tall enough (ie enough top_level) */
755
756         i = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
757         required_depth = 0;
758         while (i) {
759                 i >>= YAFFS_TNODES_INTERNAL_BITS;
760                 required_depth++;
761         }
762
763         if (required_depth > file_struct->top_level)
764                 return NULL;    /* Not tall enough, so we can't find it */
765
766         /* Traverse down to level 0 */
767         while (level > 0 && tn) {
768                 tn = tn->internal[(chunk_id >>
769                                    (YAFFS_TNODES_LEVEL0_BITS +
770                                     (level - 1) *
771                                     YAFFS_TNODES_INTERNAL_BITS)) &
772                                   YAFFS_TNODES_INTERNAL_MASK];
773                 level--;
774         }
775
776         return tn;
777 }
778
779 /* AddOrFindLevel0Tnode finds the level 0 tnode if it exists, otherwise first expands the tree.
780  * This happens in two steps:
781  *  1. If the tree isn't tall enough, then make it taller.
782  *  2. Scan down the tree towards the level 0 tnode adding tnodes if required.
783  *
784  * Used when modifying the tree.
785  *
786  *  If the tn argument is NULL, then a fresh tnode will be added otherwise the specified tn will
787  *  be plugged into the ttree.
788  */
789
790 struct yaffs_tnode *yaffs_add_find_tnode_0(struct yaffs_dev *dev,
791                                            struct yaffs_file_var *file_struct,
792                                            u32 chunk_id,
793                                            struct yaffs_tnode *passed_tn)
794 {
795         int required_depth;
796         int i;
797         int l;
798         struct yaffs_tnode *tn;
799
800         u32 x;
801
802         /* Check sane level and page Id */
803         if (file_struct->top_level < 0
804             || file_struct->top_level > YAFFS_TNODES_MAX_LEVEL)
805                 return NULL;
806
807         if (chunk_id > YAFFS_MAX_CHUNK_ID)
808                 return NULL;
809
810         /* First check we're tall enough (ie enough top_level) */
811
812         x = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
813         required_depth = 0;
814         while (x) {
815                 x >>= YAFFS_TNODES_INTERNAL_BITS;
816                 required_depth++;
817         }
818
819         if (required_depth > file_struct->top_level) {
820                 /* Not tall enough, gotta make the tree taller */
821                 for (i = file_struct->top_level; i < required_depth; i++) {
822
823                         tn = yaffs_get_tnode(dev);
824
825                         if (tn) {
826                                 tn->internal[0] = file_struct->top;
827                                 file_struct->top = tn;
828                                 file_struct->top_level++;
829                         } else {
830                                 T(YAFFS_TRACE_ERROR,
831                                   (TSTR("yaffs: no more tnodes" TENDSTR)));
832                                 return NULL;
833                         }
834                 }
835         }
836
837         /* Traverse down to level 0, adding anything we need */
838
839         l = file_struct->top_level;
840         tn = file_struct->top;
841
842         if (l > 0) {
843                 while (l > 0 && tn) {
844                         x = (chunk_id >>
845                              (YAFFS_TNODES_LEVEL0_BITS +
846                               (l - 1) * YAFFS_TNODES_INTERNAL_BITS)) &
847                             YAFFS_TNODES_INTERNAL_MASK;
848
849                         if ((l > 1) && !tn->internal[x]) {
850                                 /* Add missing non-level-zero tnode */
851                                 tn->internal[x] = yaffs_get_tnode(dev);
852                                 if (!tn->internal[x])
853                                         return NULL;
854                         } else if (l == 1) {
855                                 /* Looking from level 1 at level 0 */
856                                 if (passed_tn) {
857                                         /* If we already have one, then release it. */
858                                         if (tn->internal[x])
859                                                 yaffs_free_tnode(dev,
860                                                                  tn->
861                                                                  internal[x]);
862                                         tn->internal[x] = passed_tn;
863
864                                 } else if (!tn->internal[x]) {
865                                         /* Don't have one, none passed in */
866                                         tn->internal[x] = yaffs_get_tnode(dev);
867                                         if (!tn->internal[x])
868                                                 return NULL;
869                                 }
870                         }
871
872                         tn = tn->internal[x];
873                         l--;
874                 }
875         } else {
876                 /* top is level 0 */
877                 if (passed_tn) {
878                         memcpy(tn, passed_tn,
879                                (dev->tnode_width * YAFFS_NTNODES_LEVEL0) / 8);
880                         yaffs_free_tnode(dev, passed_tn);
881                 }
882         }
883
884         return tn;
885 }
886
887 static int yaffs_find_chunk_in_group(struct yaffs_dev *dev, int the_chunk,
888                                      struct yaffs_ext_tags *tags, int obj_id,
889                                      int inode_chunk)
890 {
891         int j;
892
893         for (j = 0; the_chunk && j < dev->chunk_grp_size; j++) {
894                 if (yaffs_check_chunk_bit
895                     (dev, the_chunk / dev->param.chunks_per_block,
896                      the_chunk % dev->param.chunks_per_block)) {
897
898                         if (dev->chunk_grp_size == 1)
899                                 return the_chunk;
900                         else {
901                                 yaffs_rd_chunk_tags_nand(dev, the_chunk, NULL,
902                                                          tags);
903                                 if (yaffs_tags_match(tags, obj_id, inode_chunk)) {
904                                         /* found it; */
905                                         return the_chunk;
906                                 }
907                         }
908                 }
909                 the_chunk++;
910         }
911         return -1;
912 }
913
914 static void yaffs_soft_del_chunk(struct yaffs_dev *dev, int chunk)
915 {
916         struct yaffs_block_info *the_block;
917         unsigned block_no;
918
919         T(YAFFS_TRACE_DELETION, (TSTR("soft delete chunk %d" TENDSTR), chunk));
920
921         block_no = chunk / dev->param.chunks_per_block;
922         the_block = yaffs_get_block_info(dev, block_no);
923         if (the_block) {
924                 the_block->soft_del_pages++;
925                 dev->n_free_chunks++;
926                 yaffs2_update_oldest_dirty_seq(dev, block_no, the_block);
927         }
928 }
929
930 /* SoftDeleteWorker scans backwards through the tnode tree and soft deletes all the chunks in the file.
931  * All soft deleting does is increment the block's softdelete count and pulls the chunk out
932  * of the tnode.
933  * Thus, essentially this is the same as DeleteWorker except that the chunks are soft deleted.
934  */
935
936 static int yaffs_soft_del_worker(struct yaffs_obj *in, struct yaffs_tnode *tn,
937                                  u32 level, int chunk_offset)
938 {
939         int i;
940         int the_chunk;
941         int all_done = 1;
942         struct yaffs_dev *dev = in->my_dev;
943
944         if (tn) {
945                 if (level > 0) {
946
947                         for (i = YAFFS_NTNODES_INTERNAL - 1; all_done && i >= 0;
948                              i--) {
949                                 if (tn->internal[i]) {
950                                         all_done =
951                                             yaffs_soft_del_worker(in,
952                                                                   tn->internal
953                                                                   [i],
954                                                                   level - 1,
955                                                                   (chunk_offset
956                                                                    <<
957                                                                    YAFFS_TNODES_INTERNAL_BITS)
958                                                                   + i);
959                                         if (all_done) {
960                                                 yaffs_free_tnode(dev,
961                                                                  tn->internal
962                                                                  [i]);
963                                                 tn->internal[i] = NULL;
964                                         } else {
965                                                 /* Hoosterman... how could this happen? */
966                                         }
967                                 }
968                         }
969                         return (all_done) ? 1 : 0;
970                 } else if (level == 0) {
971
972                         for (i = YAFFS_NTNODES_LEVEL0 - 1; i >= 0; i--) {
973                                 the_chunk = yaffs_get_group_base(dev, tn, i);
974                                 if (the_chunk) {
975                                         /* Note this does not find the real chunk, only the chunk group.
976                                          * We make an assumption that a chunk group is not larger than
977                                          * a block.
978                                          */
979                                         yaffs_soft_del_chunk(dev, the_chunk);
980                                         yaffs_load_tnode_0(dev, tn, i, 0);
981                                 }
982
983                         }
984                         return 1;
985
986                 }
987
988         }
989
990         return 1;
991
992 }
993
994 static void yaffs_soft_del_file(struct yaffs_obj *obj)
995 {
996         if (obj->deleted &&
997             obj->variant_type == YAFFS_OBJECT_TYPE_FILE && !obj->soft_del) {
998                 if (obj->n_data_chunks <= 0) {
999                         /* Empty file with no duplicate object headers, just delete it immediately */
1000                         yaffs_free_tnode(obj->my_dev,
1001                                          obj->variant.file_variant.top);
1002                         obj->variant.file_variant.top = NULL;
1003                         T(YAFFS_TRACE_TRACING,
1004                           (TSTR("yaffs: Deleting empty file %d" TENDSTR),
1005                            obj->obj_id));
1006                         yaffs_generic_obj_del(obj);
1007                 } else {
1008                         yaffs_soft_del_worker(obj,
1009                                               obj->variant.file_variant.top,
1010                                               obj->variant.
1011                                               file_variant.top_level, 0);
1012                         obj->soft_del = 1;
1013                 }
1014         }
1015 }
1016
1017 /* Pruning removes any part of the file structure tree that is beyond the
1018  * bounds of the file (ie that does not point to chunks).
1019  *
1020  * A file should only get pruned when its size is reduced.
1021  *
1022  * Before pruning, the chunks must be pulled from the tree and the
1023  * level 0 tnode entries must be zeroed out.
1024  * Could also use this for file deletion, but that's probably better handled
1025  * by a special case.
1026  *
1027  * This function is recursive. For levels > 0 the function is called again on
1028  * any sub-tree. For level == 0 we just check if the sub-tree has data.
1029  * If there is no data in a subtree then it is pruned.
1030  */
1031
1032 static struct yaffs_tnode *yaffs_prune_worker(struct yaffs_dev *dev,
1033                                               struct yaffs_tnode *tn, u32 level,
1034                                               int del0)
1035 {
1036         int i;
1037         int has_data;
1038
1039         if (tn) {
1040                 has_data = 0;
1041
1042                 if (level > 0) {
1043                         for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++) {
1044                                 if (tn->internal[i]) {
1045                                         tn->internal[i] =
1046                                             yaffs_prune_worker(dev,
1047                                                                tn->internal[i],
1048                                                                level - 1,
1049                                                                (i ==
1050                                                                 0) ? del0 : 1);
1051                                 }
1052
1053                                 if (tn->internal[i])
1054                                         has_data++;
1055                         }
1056                 } else {
1057                         int tnode_size_u32 = dev->tnode_size / sizeof(u32);
1058                         u32 *map = (u32 *) tn;
1059
1060                         for (i = 0; !has_data && i < tnode_size_u32; i++) {
1061                                 if (map[i])
1062                                         has_data++;
1063                         }
1064                 }
1065
1066                 if (has_data == 0 && del0) {
1067                         /* Free and return NULL */
1068
1069                         yaffs_free_tnode(dev, tn);
1070                         tn = NULL;
1071                 }
1072
1073         }
1074
1075         return tn;
1076
1077 }
1078
1079 static int yaffs_prune_tree(struct yaffs_dev *dev,
1080                             struct yaffs_file_var *file_struct)
1081 {
1082         int i;
1083         int has_data;
1084         int done = 0;
1085         struct yaffs_tnode *tn;
1086
1087         if (file_struct->top_level > 0) {
1088                 file_struct->top =
1089                     yaffs_prune_worker(dev, file_struct->top,
1090                                        file_struct->top_level, 0);
1091
1092                 /* Now we have a tree with all the non-zero branches NULL but the height
1093                  * is the same as it was.
1094                  * Let's see if we can trim internal tnodes to shorten the tree.
1095                  * We can do this if only the 0th element in the tnode is in use
1096                  * (ie all the non-zero are NULL)
1097                  */
1098
1099                 while (file_struct->top_level && !done) {
1100                         tn = file_struct->top;
1101
1102                         has_data = 0;
1103                         for (i = 1; i < YAFFS_NTNODES_INTERNAL; i++) {
1104                                 if (tn->internal[i])
1105                                         has_data++;
1106                         }
1107
1108                         if (!has_data) {
1109                                 file_struct->top = tn->internal[0];
1110                                 file_struct->top_level--;
1111                                 yaffs_free_tnode(dev, tn);
1112                         } else {
1113                                 done = 1;
1114                         }
1115                 }
1116         }
1117
1118         return YAFFS_OK;
1119 }
1120
1121 /*-------------------- End of File Structure functions.-------------------*/
1122
1123 /* AllocateEmptyObject gets us a clean Object. Tries to make allocate more if we run out */
1124 static struct yaffs_obj *yaffs_alloc_empty_obj(struct yaffs_dev *dev)
1125 {
1126         struct yaffs_obj *obj = yaffs_alloc_raw_obj(dev);
1127
1128         if (obj) {
1129                 dev->n_obj++;
1130
1131                 /* Now sweeten it up... */
1132
1133                 memset(obj, 0, sizeof(struct yaffs_obj));
1134                 obj->being_created = 1;
1135
1136                 obj->my_dev = dev;
1137                 obj->hdr_chunk = 0;
1138                 obj->variant_type = YAFFS_OBJECT_TYPE_UNKNOWN;
1139                 INIT_LIST_HEAD(&(obj->hard_links));
1140                 INIT_LIST_HEAD(&(obj->hash_link));
1141                 INIT_LIST_HEAD(&obj->siblings);
1142
1143                 /* Now make the directory sane */
1144                 if (dev->root_dir) {
1145                         obj->parent = dev->root_dir;
1146                         list_add(&(obj->siblings),
1147                                  &dev->root_dir->variant.dir_variant.children);
1148                 }
1149
1150                 /* Add it to the lost and found directory.
1151                  * NB Can't put root or lost-n-found in lost-n-found so
1152                  * check if lost-n-found exists first
1153                  */
1154                 if (dev->lost_n_found)
1155                         yaffs_add_obj_to_dir(dev->lost_n_found, obj);
1156
1157                 obj->being_created = 0;
1158         }
1159
1160         dev->checkpoint_blocks_required = 0;    /* force recalculation */
1161
1162         return obj;
1163 }
1164
1165 static struct yaffs_obj *yaffs_create_fake_dir(struct yaffs_dev *dev,
1166                                                int number, u32 mode)
1167 {
1168
1169         struct yaffs_obj *obj =
1170             yaffs_new_obj(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
1171         if (obj) {
1172                 obj->fake = 1;  /* it is fake so it might have no NAND presence... */
1173                 obj->rename_allowed = 0;        /* ... and we're not allowed to rename it... */
1174                 obj->unlink_allowed = 0;        /* ... or unlink it */
1175                 obj->deleted = 0;
1176                 obj->unlinked = 0;
1177                 obj->yst_mode = mode;
1178                 obj->my_dev = dev;
1179                 obj->hdr_chunk = 0;     /* Not a valid chunk. */
1180         }
1181
1182         return obj;
1183
1184 }
1185
1186 static void yaffs_unhash_obj(struct yaffs_obj *obj)
1187 {
1188         int bucket;
1189         struct yaffs_dev *dev = obj->my_dev;
1190
1191         /* If it is still linked into the bucket list, free from the list */
1192         if (!list_empty(&obj->hash_link)) {
1193                 list_del_init(&obj->hash_link);
1194                 bucket = yaffs_hash_fn(obj->obj_id);
1195                 dev->obj_bucket[bucket].count--;
1196         }
1197 }
1198
1199 /*  FreeObject frees up a Object and puts it back on the free list */
1200 static void yaffs_free_obj(struct yaffs_obj *obj)
1201 {
1202         struct yaffs_dev *dev = obj->my_dev;
1203
1204         T(YAFFS_TRACE_OS,
1205           (TSTR("FreeObject %p inode %p" TENDSTR), obj, obj->my_inode));
1206
1207         if (!obj)
1208                 YBUG();
1209         if (obj->parent)
1210                 YBUG();
1211         if (!list_empty(&obj->siblings))
1212                 YBUG();
1213
1214         if (obj->my_inode) {
1215                 /* We're still hooked up to a cached inode.
1216                  * Don't delete now, but mark for later deletion
1217                  */
1218                 obj->defered_free = 1;
1219                 return;
1220         }
1221
1222         yaffs_unhash_obj(obj);
1223
1224         yaffs_free_raw_obj(dev, obj);
1225         dev->n_obj--;
1226         dev->checkpoint_blocks_required = 0;    /* force recalculation */
1227 }
1228
1229 void yaffs_handle_defered_free(struct yaffs_obj *obj)
1230 {
1231         if (obj->defered_free)
1232                 yaffs_free_obj(obj);
1233 }
1234
1235 static void yaffs_init_tnodes_and_objs(struct yaffs_dev *dev)
1236 {
1237         int i;
1238
1239         dev->n_obj = 0;
1240         dev->n_tnodes = 0;
1241
1242         yaffs_init_raw_tnodes_and_objs(dev);
1243
1244         for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
1245                 INIT_LIST_HEAD(&dev->obj_bucket[i].list);
1246                 dev->obj_bucket[i].count = 0;
1247         }
1248 }
1249
1250 static int yaffs_find_nice_bucket(struct yaffs_dev *dev)
1251 {
1252         int i;
1253         int l = 999;
1254         int lowest = 999999;
1255
1256         /* Search for the shortest list or one that
1257          * isn't too long.
1258          */
1259
1260         for (i = 0; i < 10 && lowest > 4; i++) {
1261                 dev->bucket_finder++;
1262                 dev->bucket_finder %= YAFFS_NOBJECT_BUCKETS;
1263                 if (dev->obj_bucket[dev->bucket_finder].count < lowest) {
1264                         lowest = dev->obj_bucket[dev->bucket_finder].count;
1265                         l = dev->bucket_finder;
1266                 }
1267
1268         }
1269
1270         return l;
1271 }
1272
1273 static int yaffs_new_obj_id(struct yaffs_dev *dev)
1274 {
1275         int bucket = yaffs_find_nice_bucket(dev);
1276
1277         /* Now find an object value that has not already been taken
1278          * by scanning the list.
1279          */
1280
1281         int found = 0;
1282         struct list_head *i;
1283
1284         u32 n = (u32) bucket;
1285
1286         /* yaffs_check_obj_hash_sane();  */
1287
1288         while (!found) {
1289                 found = 1;
1290                 n += YAFFS_NOBJECT_BUCKETS;
1291                 if (1 || dev->obj_bucket[bucket].count > 0) {
1292                         list_for_each(i, &dev->obj_bucket[bucket].list) {
1293                                 /* If there is already one in the list */
1294                                 if (i && list_entry(i, struct yaffs_obj,
1295                                                     hash_link)->obj_id == n) {
1296                                         found = 0;
1297                                 }
1298                         }
1299                 }
1300         }
1301
1302         return n;
1303 }
1304
1305 static void yaffs_hash_obj(struct yaffs_obj *in)
1306 {
1307         int bucket = yaffs_hash_fn(in->obj_id);
1308         struct yaffs_dev *dev = in->my_dev;
1309
1310         list_add(&in->hash_link, &dev->obj_bucket[bucket].list);
1311         dev->obj_bucket[bucket].count++;
1312 }
1313
1314 struct yaffs_obj *yaffs_find_by_number(struct yaffs_dev *dev, u32 number)
1315 {
1316         int bucket = yaffs_hash_fn(number);
1317         struct list_head *i;
1318         struct yaffs_obj *in;
1319
1320         list_for_each(i, &dev->obj_bucket[bucket].list) {
1321                 /* Look if it is in the list */
1322                 if (i) {
1323                         in = list_entry(i, struct yaffs_obj, hash_link);
1324                         if (in->obj_id == number) {
1325
1326                                 /* Don't tell the VFS about this one if it is defered free */
1327                                 if (in->defered_free)
1328                                         return NULL;
1329
1330                                 return in;
1331                         }
1332                 }
1333         }
1334
1335         return NULL;
1336 }
1337
1338 struct yaffs_obj *yaffs_new_obj(struct yaffs_dev *dev, int number,
1339                                 enum yaffs_obj_type type)
1340 {
1341         struct yaffs_obj *the_obj = NULL;
1342         struct yaffs_tnode *tn = NULL;
1343
1344         if (number < 0)
1345                 number = yaffs_new_obj_id(dev);
1346
1347         if (type == YAFFS_OBJECT_TYPE_FILE) {
1348                 tn = yaffs_get_tnode(dev);
1349                 if (!tn)
1350                         return NULL;
1351         }
1352
1353         the_obj = yaffs_alloc_empty_obj(dev);
1354         if (!the_obj) {
1355                 if (tn)
1356                         yaffs_free_tnode(dev, tn);
1357                 return NULL;
1358         }
1359
1360         if (the_obj) {
1361                 the_obj->fake = 0;
1362                 the_obj->rename_allowed = 1;
1363                 the_obj->unlink_allowed = 1;
1364                 the_obj->obj_id = number;
1365                 yaffs_hash_obj(the_obj);
1366                 the_obj->variant_type = type;
1367                 yaffs_load_current_time(the_obj, 1, 1);
1368
1369                 switch (type) {
1370                 case YAFFS_OBJECT_TYPE_FILE:
1371                         the_obj->variant.file_variant.file_size = 0;
1372                         the_obj->variant.file_variant.scanned_size = 0;
1373                         the_obj->variant.file_variant.shrink_size = ~0; /* max */
1374                         the_obj->variant.file_variant.top_level = 0;
1375                         the_obj->variant.file_variant.top = tn;
1376                         break;
1377                 case YAFFS_OBJECT_TYPE_DIRECTORY:
1378                         INIT_LIST_HEAD(&the_obj->variant.dir_variant.children);
1379                         INIT_LIST_HEAD(&the_obj->variant.dir_variant.dirty);
1380                         break;
1381                 case YAFFS_OBJECT_TYPE_SYMLINK:
1382                 case YAFFS_OBJECT_TYPE_HARDLINK:
1383                 case YAFFS_OBJECT_TYPE_SPECIAL:
1384                         /* No action required */
1385                         break;
1386                 case YAFFS_OBJECT_TYPE_UNKNOWN:
1387                         /* todo this should not happen */
1388                         break;
1389                 }
1390         }
1391
1392         return the_obj;
1393 }
1394
1395 struct yaffs_obj *yaffs_find_or_create_by_number(struct yaffs_dev *dev,
1396                                                  int number,
1397                                                  enum yaffs_obj_type type)
1398 {
1399         struct yaffs_obj *the_obj = NULL;
1400
1401         if (number > 0)
1402                 the_obj = yaffs_find_by_number(dev, number);
1403
1404         if (!the_obj)
1405                 the_obj = yaffs_new_obj(dev, number, type);
1406
1407         return the_obj;
1408
1409 }
1410
1411 YCHAR *yaffs_clone_str(const YCHAR * str)
1412 {
1413         YCHAR *new_str = NULL;
1414         int len;
1415
1416         if (!str)
1417                 str = _Y("");
1418
1419         len = yaffs_strnlen(str, YAFFS_MAX_ALIAS_LENGTH);
1420         new_str = YMALLOC((len + 1) * sizeof(YCHAR));
1421         if (new_str) {
1422                 yaffs_strncpy(new_str, str, len);
1423                 new_str[len] = 0;
1424         }
1425         return new_str;
1426
1427 }
1428
1429 /*
1430  * Mknod (create) a new object.
1431  * equiv_obj only has meaning for a hard link;
1432  * alias_str only has meaning for a symlink.
1433  * rdev only has meaning for devices (a subset of special objects)
1434  */
1435
1436 static struct yaffs_obj *yaffs_create_obj(enum yaffs_obj_type type,
1437                                           struct yaffs_obj *parent,
1438                                           const YCHAR * name,
1439                                           u32 mode,
1440                                           u32 uid,
1441                                           u32 gid,
1442                                           struct yaffs_obj *equiv_obj,
1443                                           const YCHAR * alias_str, u32 rdev)
1444 {
1445         struct yaffs_obj *in;
1446         YCHAR *str = NULL;
1447
1448         struct yaffs_dev *dev = parent->my_dev;
1449
1450         /* Check if the entry exists. If it does then fail the call since we don't want a dup. */
1451         if (yaffs_find_by_name(parent, name))
1452                 return NULL;
1453
1454         if (type == YAFFS_OBJECT_TYPE_SYMLINK) {
1455                 str = yaffs_clone_str(alias_str);
1456                 if (!str)
1457                         return NULL;
1458         }
1459
1460         in = yaffs_new_obj(dev, -1, type);
1461
1462         if (!in) {
1463                 if (str)
1464                         YFREE(str);
1465                 return NULL;
1466         }
1467
1468         if (in) {
1469                 in->hdr_chunk = 0;
1470                 in->valid = 1;
1471                 in->variant_type = type;
1472
1473                 in->yst_mode = mode;
1474
1475                 yaffs_attribs_init(in, gid, uid, rdev);
1476
1477                 in->n_data_chunks = 0;
1478
1479                 yaffs_set_obj_name(in, name);
1480                 in->dirty = 1;
1481
1482                 yaffs_add_obj_to_dir(parent, in);
1483
1484                 in->my_dev = parent->my_dev;
1485
1486                 switch (type) {
1487                 case YAFFS_OBJECT_TYPE_SYMLINK:
1488                         in->variant.symlink_variant.alias = str;
1489                         break;
1490                 case YAFFS_OBJECT_TYPE_HARDLINK:
1491                         in->variant.hardlink_variant.equiv_obj = equiv_obj;
1492                         in->variant.hardlink_variant.equiv_id =
1493                             equiv_obj->obj_id;
1494                         list_add(&in->hard_links, &equiv_obj->hard_links);
1495                         break;
1496                 case YAFFS_OBJECT_TYPE_FILE:
1497                 case YAFFS_OBJECT_TYPE_DIRECTORY:
1498                 case YAFFS_OBJECT_TYPE_SPECIAL:
1499                 case YAFFS_OBJECT_TYPE_UNKNOWN:
1500                         /* do nothing */
1501                         break;
1502                 }
1503
1504                 if (yaffs_update_oh(in, name, 0, 0, 0, NULL) < 0) {
1505                         /* Could not create the object header, fail the creation */
1506                         yaffs_del_obj(in);
1507                         in = NULL;
1508                 }
1509
1510                 yaffs_update_parent(parent);
1511         }
1512
1513         return in;
1514 }
1515
1516 struct yaffs_obj *yaffs_create_file(struct yaffs_obj *parent,
1517                                     const YCHAR * name, u32 mode, u32 uid,
1518                                     u32 gid)
1519 {
1520         return yaffs_create_obj(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
1521                                 uid, gid, NULL, NULL, 0);
1522 }
1523
1524 struct yaffs_obj *yaffs_create_dir(struct yaffs_obj *parent, const YCHAR * name,
1525                                    u32 mode, u32 uid, u32 gid)
1526 {
1527         return yaffs_create_obj(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
1528                                 mode, uid, gid, NULL, NULL, 0);
1529 }
1530
1531 struct yaffs_obj *yaffs_create_special(struct yaffs_obj *parent,
1532                                        const YCHAR * name, u32 mode, u32 uid,
1533                                        u32 gid, u32 rdev)
1534 {
1535         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
1536                                 uid, gid, NULL, NULL, rdev);
1537 }
1538
1539 struct yaffs_obj *yaffs_create_symlink(struct yaffs_obj *parent,
1540                                        const YCHAR * name, u32 mode, u32 uid,
1541                                        u32 gid, const YCHAR * alias)
1542 {
1543         return yaffs_create_obj(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
1544                                 uid, gid, NULL, alias, 0);
1545 }
1546
1547 /* yaffs_link_obj returns the object id of the equivalent object.*/
1548 struct yaffs_obj *yaffs_link_obj(struct yaffs_obj *parent, const YCHAR * name,
1549                                  struct yaffs_obj *equiv_obj)
1550 {
1551         /* Get the real object in case we were fed a hard link as an equivalent object */
1552         equiv_obj = yaffs_get_equivalent_obj(equiv_obj);
1553
1554         if (yaffs_create_obj
1555             (YAFFS_OBJECT_TYPE_HARDLINK, parent, name, 0, 0, 0,
1556              equiv_obj, NULL, 0)) {
1557                 return equiv_obj;
1558         } else {
1559                 return NULL;
1560         }
1561
1562 }
1563
1564 static int yaffs_change_obj_name(struct yaffs_obj *obj,
1565                                  struct yaffs_obj *new_dir,
1566                                  const YCHAR * new_name, int force, int shadows)
1567 {
1568         int unlink_op;
1569         int del_op;
1570
1571         struct yaffs_obj *existing_target;
1572
1573         if (new_dir == NULL)
1574                 new_dir = obj->parent;  /* use the old directory */
1575
1576         if (new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
1577                 T(YAFFS_TRACE_ALWAYS,
1578                   (TSTR
1579                    ("tragedy: yaffs_change_obj_name: new_dir is not a directory"
1580                     TENDSTR)));
1581                 YBUG();
1582         }
1583
1584         /* TODO: Do we need this different handling for YAFFS2 and YAFFS1?? */
1585         if (obj->my_dev->param.is_yaffs2)
1586                 unlink_op = (new_dir == obj->my_dev->unlinked_dir);
1587         else
1588                 unlink_op = (new_dir == obj->my_dev->unlinked_dir
1589                              && obj->variant_type == YAFFS_OBJECT_TYPE_FILE);
1590
1591         del_op = (new_dir == obj->my_dev->del_dir);
1592
1593         existing_target = yaffs_find_by_name(new_dir, new_name);
1594
1595         /* If the object is a file going into the unlinked directory,
1596          *   then it is OK to just stuff it in since duplicate names are allowed.
1597          *   else only proceed if the new name does not exist and if we're putting
1598          *   it into a directory.
1599          */
1600         if ((unlink_op ||
1601              del_op ||
1602              force ||
1603              (shadows > 0) ||
1604              !existing_target) &&
1605             new_dir->variant_type == YAFFS_OBJECT_TYPE_DIRECTORY) {
1606                 yaffs_set_obj_name(obj, new_name);
1607                 obj->dirty = 1;
1608
1609                 yaffs_add_obj_to_dir(new_dir, obj);
1610
1611                 if (unlink_op)
1612                         obj->unlinked = 1;
1613
1614                 /* If it is a deletion then we mark it as a shrink for gc purposes. */
1615                 if (yaffs_update_oh(obj, new_name, 0, del_op, shadows, NULL) >=
1616                     0)
1617                         return YAFFS_OK;
1618         }
1619
1620         return YAFFS_FAIL;
1621 }
1622
1623
1624 /* Note:
1625  * If old_name is NULL then we take old_dir as the object to be renamed.
1626  */
1627 int yaffs_rename_obj(struct yaffs_obj *old_dir, const YCHAR * old_name,
1628                      struct yaffs_obj *new_dir, const YCHAR * new_name)
1629 {
1630         struct yaffs_obj *obj = NULL;
1631         struct yaffs_obj *existing_target = NULL;
1632         int force = 0;
1633         int result;
1634         struct yaffs_dev *dev;
1635
1636         if (!old_dir || old_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
1637                 YBUG();
1638         if (!new_dir || new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
1639                 YBUG();
1640
1641         dev = old_dir->my_dev;
1642
1643 #ifdef CONFIG_YAFFS_CASE_INSENSITIVE
1644         /* Special case for case insemsitive systems.
1645          * While look-up is case insensitive, the name isn't.
1646          * Therefore we might want to change x.txt to X.txt
1647          */
1648         if (old_dir == new_dir && 
1649                 old_name && new_name && 
1650                 yaffs_strcmp(old_name, new_name) == 0)
1651                 force = 1;
1652 #endif
1653
1654         if (yaffs_strnlen(new_name, YAFFS_MAX_NAME_LENGTH + 1) >
1655             YAFFS_MAX_NAME_LENGTH)
1656                 /* ENAMETOOLONG */
1657                 return YAFFS_FAIL;
1658
1659         if(old_name)
1660                 obj = yaffs_find_by_name(old_dir, old_name);
1661         else{
1662                 obj = old_dir;
1663                 old_dir = obj->parent;
1664         }
1665
1666
1667         if (obj && obj->rename_allowed) {
1668
1669                 /* Now do the handling for an existing target, if there is one */
1670
1671                 existing_target = yaffs_find_by_name(new_dir, new_name);
1672                 if (yaffs_is_non_empty_dir(existing_target)){
1673                         return YAFFS_FAIL;      /* ENOTEMPTY */
1674                 } else if (existing_target && existing_target != obj) {
1675                         /* Nuke the target first, using shadowing,
1676                          * but only if it isn't the same object.
1677                          *
1678                          * Note we must disable gc otherwise it can mess up the shadowing.
1679                          *
1680                          */
1681                         dev->gc_disable = 1;
1682                         yaffs_change_obj_name(obj, new_dir, new_name, force,
1683                                               existing_target->obj_id);
1684                         existing_target->is_shadowed = 1;
1685                         yaffs_unlink_obj(existing_target);
1686                         dev->gc_disable = 0;
1687                 }
1688
1689                 result = yaffs_change_obj_name(obj, new_dir, new_name, 1, 0);
1690
1691                 yaffs_update_parent(old_dir);
1692                 if (new_dir != old_dir)
1693                         yaffs_update_parent(new_dir);
1694
1695                 return result;
1696         }
1697         return YAFFS_FAIL;
1698 }
1699
1700 /*------------------------- Block Management and Page Allocation ----------------*/
1701
1702 static int yaffs_init_blocks(struct yaffs_dev *dev)
1703 {
1704         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
1705
1706         dev->block_info = NULL;
1707         dev->chunk_bits = NULL;
1708
1709         dev->alloc_block = -1;  /* force it to get a new one */
1710
1711         /* If the first allocation strategy fails, thry the alternate one */
1712         dev->block_info = YMALLOC(n_blocks * sizeof(struct yaffs_block_info));
1713         if (!dev->block_info) {
1714                 dev->block_info =
1715                     YMALLOC_ALT(n_blocks * sizeof(struct yaffs_block_info));
1716                 dev->block_info_alt = 1;
1717         } else {
1718                 dev->block_info_alt = 0;
1719         }
1720
1721         if (dev->block_info) {
1722                 /* Set up dynamic blockinfo stuff. */
1723                 dev->chunk_bit_stride = (dev->param.chunks_per_block + 7) / 8;  /* round up bytes */
1724                 dev->chunk_bits = YMALLOC(dev->chunk_bit_stride * n_blocks);
1725                 if (!dev->chunk_bits) {
1726                         dev->chunk_bits =
1727                             YMALLOC_ALT(dev->chunk_bit_stride * n_blocks);
1728                         dev->chunk_bits_alt = 1;
1729                 } else {
1730                         dev->chunk_bits_alt = 0;
1731                 }
1732         }
1733
1734         if (dev->block_info && dev->chunk_bits) {
1735                 memset(dev->block_info, 0,
1736                        n_blocks * sizeof(struct yaffs_block_info));
1737                 memset(dev->chunk_bits, 0, dev->chunk_bit_stride * n_blocks);
1738                 return YAFFS_OK;
1739         }
1740
1741         return YAFFS_FAIL;
1742 }
1743
1744 static void yaffs_deinit_blocks(struct yaffs_dev *dev)
1745 {
1746         if (dev->block_info_alt && dev->block_info)
1747                 YFREE_ALT(dev->block_info);
1748         else if (dev->block_info)
1749                 YFREE(dev->block_info);
1750
1751         dev->block_info_alt = 0;
1752
1753         dev->block_info = NULL;
1754
1755         if (dev->chunk_bits_alt && dev->chunk_bits)
1756                 YFREE_ALT(dev->chunk_bits);
1757         else if (dev->chunk_bits)
1758                 YFREE(dev->chunk_bits);
1759         dev->chunk_bits_alt = 0;
1760         dev->chunk_bits = NULL;
1761 }
1762
1763 void yaffs_block_became_dirty(struct yaffs_dev *dev, int block_no)
1764 {
1765         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block_no);
1766
1767         int erased_ok = 0;
1768
1769         /* If the block is still healthy erase it and mark as clean.
1770          * If the block has had a data failure, then retire it.
1771          */
1772
1773         T(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
1774           (TSTR("yaffs_block_became_dirty block %d state %d %s" TENDSTR),
1775            block_no, bi->block_state,
1776            (bi->needs_retiring) ? "needs retiring" : ""));
1777
1778         yaffs2_clear_oldest_dirty_seq(dev, bi);
1779
1780         bi->block_state = YAFFS_BLOCK_STATE_DIRTY;
1781
1782         /* If this is the block being garbage collected then stop gc'ing this block */
1783         if (block_no == dev->gc_block)
1784                 dev->gc_block = 0;
1785
1786         /* If this block is currently the best candidate for gc then drop as a candidate */
1787         if (block_no == dev->gc_dirtiest) {
1788                 dev->gc_dirtiest = 0;
1789                 dev->gc_pages_in_use = 0;
1790         }
1791
1792         if (!bi->needs_retiring) {
1793                 yaffs2_checkpt_invalidate(dev);
1794                 erased_ok = yaffs_erase_block(dev, block_no);
1795                 if (!erased_ok) {
1796                         dev->n_erase_failures++;
1797                         T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
1798                           (TSTR("**>> Erasure failed %d" TENDSTR), block_no));
1799                 }
1800         }
1801
1802         if (erased_ok &&
1803             ((yaffs_trace_mask & YAFFS_TRACE_ERASE)
1804              || !yaffs_skip_verification(dev))) {
1805                 int i;
1806                 for (i = 0; i < dev->param.chunks_per_block; i++) {
1807                         if (!yaffs_check_chunk_erased
1808                             (dev, block_no * dev->param.chunks_per_block + i)) {
1809                                 T(YAFFS_TRACE_ERROR,
1810                                   (TSTR
1811                                    (">>Block %d erasure supposedly OK, but chunk %d not erased"
1812                                     TENDSTR), block_no, i));
1813                         }
1814                 }
1815         }
1816
1817         if (erased_ok) {
1818                 /* Clean it up... */
1819                 bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
1820                 bi->seq_number = 0;
1821                 dev->n_erased_blocks++;
1822                 bi->pages_in_use = 0;
1823                 bi->soft_del_pages = 0;
1824                 bi->has_shrink_hdr = 0;
1825                 bi->skip_erased_check = 1;      /* This is clean, so no need to check */
1826                 bi->gc_prioritise = 0;
1827                 yaffs_clear_chunk_bits(dev, block_no);
1828
1829                 T(YAFFS_TRACE_ERASE,
1830                   (TSTR("Erased block %d" TENDSTR), block_no));
1831         } else {
1832                 dev->n_free_chunks -= dev->param.chunks_per_block;      /* We lost a block of free space */
1833
1834                 yaffs_retire_block(dev, block_no);
1835                 T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
1836                   (TSTR("**>> Block %d retired" TENDSTR), block_no));
1837         }
1838 }
1839
1840 static int yaffs_find_alloc_block(struct yaffs_dev *dev)
1841 {
1842         int i;
1843
1844         struct yaffs_block_info *bi;
1845
1846         if (dev->n_erased_blocks < 1) {
1847                 /* Hoosterman we've got a problem.
1848                  * Can't get space to gc
1849                  */
1850                 T(YAFFS_TRACE_ERROR,
1851                   (TSTR("yaffs tragedy: no more erased blocks" TENDSTR)));
1852
1853                 return -1;
1854         }
1855
1856         /* Find an empty block. */
1857
1858         for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
1859                 dev->alloc_block_finder++;
1860                 if (dev->alloc_block_finder < dev->internal_start_block
1861                     || dev->alloc_block_finder > dev->internal_end_block) {
1862                         dev->alloc_block_finder = dev->internal_start_block;
1863                 }
1864
1865                 bi = yaffs_get_block_info(dev, dev->alloc_block_finder);
1866
1867                 if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
1868                         bi->block_state = YAFFS_BLOCK_STATE_ALLOCATING;
1869                         dev->seq_number++;
1870                         bi->seq_number = dev->seq_number;
1871                         dev->n_erased_blocks--;
1872                         T(YAFFS_TRACE_ALLOCATE,
1873                           (TSTR("Allocated block %d, seq  %d, %d left" TENDSTR),
1874                            dev->alloc_block_finder, dev->seq_number,
1875                            dev->n_erased_blocks));
1876                         return dev->alloc_block_finder;
1877                 }
1878         }
1879
1880         T(YAFFS_TRACE_ALWAYS,
1881           (TSTR
1882            ("yaffs tragedy: no more erased blocks, but there should have been %d"
1883             TENDSTR), dev->n_erased_blocks));
1884
1885         return -1;
1886 }
1887
1888 /*
1889  * Check if there's space to allocate...
1890  * Thinks.... do we need top make this ths same as yaffs_get_free_chunks()?
1891  */
1892 int yaffs_check_alloc_available(struct yaffs_dev *dev, int n_chunks)
1893 {
1894         int reserved_chunks;
1895         int reserved_blocks = dev->param.n_reserved_blocks;
1896         int checkpt_blocks;
1897
1898         checkpt_blocks = yaffs_calc_checkpt_blocks_required(dev);
1899
1900         reserved_chunks =
1901             ((reserved_blocks + checkpt_blocks) * dev->param.chunks_per_block);
1902
1903         return (dev->n_free_chunks > (reserved_chunks + n_chunks));
1904 }
1905
1906 static int yaffs_alloc_chunk(struct yaffs_dev *dev, int use_reserver,
1907                              struct yaffs_block_info **block_ptr)
1908 {
1909         int ret_val;
1910         struct yaffs_block_info *bi;
1911
1912         if (dev->alloc_block < 0) {
1913                 /* Get next block to allocate off */
1914                 dev->alloc_block = yaffs_find_alloc_block(dev);
1915                 dev->alloc_page = 0;
1916         }
1917
1918         if (!use_reserver && !yaffs_check_alloc_available(dev, 1)) {
1919                 /* Not enough space to allocate unless we're allowed to use the reserve. */
1920                 return -1;
1921         }
1922
1923         if (dev->n_erased_blocks < dev->param.n_reserved_blocks
1924             && dev->alloc_page == 0) {
1925                 T(YAFFS_TRACE_ALLOCATE, (TSTR("Allocating reserve" TENDSTR)));
1926         }
1927
1928         /* Next page please.... */
1929         if (dev->alloc_block >= 0) {
1930                 bi = yaffs_get_block_info(dev, dev->alloc_block);
1931
1932                 ret_val = (dev->alloc_block * dev->param.chunks_per_block) +
1933                     dev->alloc_page;
1934                 bi->pages_in_use++;
1935                 yaffs_set_chunk_bit(dev, dev->alloc_block, dev->alloc_page);
1936
1937                 dev->alloc_page++;
1938
1939                 dev->n_free_chunks--;
1940
1941                 /* If the block is full set the state to full */
1942                 if (dev->alloc_page >= dev->param.chunks_per_block) {
1943                         bi->block_state = YAFFS_BLOCK_STATE_FULL;
1944                         dev->alloc_block = -1;
1945                 }
1946
1947                 if (block_ptr)
1948                         *block_ptr = bi;
1949
1950                 return ret_val;
1951         }
1952
1953         T(YAFFS_TRACE_ERROR,
1954           (TSTR("!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!" TENDSTR)));
1955
1956         return -1;
1957 }
1958
1959 static int yaffs_get_erased_chunks(struct yaffs_dev *dev)
1960 {
1961         int n;
1962
1963         n = dev->n_erased_blocks * dev->param.chunks_per_block;
1964
1965         if (dev->alloc_block > 0)
1966                 n += (dev->param.chunks_per_block - dev->alloc_page);
1967
1968         return n;
1969
1970 }
1971
1972 /*
1973  * yaffs_skip_rest_of_block() skips over the rest of the allocation block
1974  * if we don't want to write to it.
1975  */
1976 void yaffs_skip_rest_of_block(struct yaffs_dev *dev)
1977 {
1978         if (dev->alloc_block > 0) {
1979                 struct yaffs_block_info *bi =
1980                     yaffs_get_block_info(dev, dev->alloc_block);
1981                 if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING) {
1982                         bi->block_state = YAFFS_BLOCK_STATE_FULL;
1983                         dev->alloc_block = -1;
1984                 }
1985         }
1986 }
1987
1988 static int yaffs_gc_block(struct yaffs_dev *dev, int block, int whole_block)
1989 {
1990         int old_chunk;
1991         int new_chunk;
1992         int mark_flash;
1993         int ret_val = YAFFS_OK;
1994         int i;
1995         int is_checkpt_block;
1996         int matching_chunk;
1997         int max_copies;
1998
1999         int chunks_before = yaffs_get_erased_chunks(dev);
2000         int chunks_after;
2001
2002         struct yaffs_ext_tags tags;
2003
2004         struct yaffs_block_info *bi = yaffs_get_block_info(dev, block);
2005
2006         struct yaffs_obj *object;
2007
2008         is_checkpt_block = (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT);
2009
2010         T(YAFFS_TRACE_TRACING,
2011           (TSTR
2012            ("Collecting block %d, in use %d, shrink %d, whole_block %d"
2013             TENDSTR), block, bi->pages_in_use, bi->has_shrink_hdr,
2014            whole_block));
2015
2016         /*yaffs_verify_free_chunks(dev); */
2017
2018         if (bi->block_state == YAFFS_BLOCK_STATE_FULL)
2019                 bi->block_state = YAFFS_BLOCK_STATE_COLLECTING;
2020
2021         bi->has_shrink_hdr = 0; /* clear the flag so that the block can erase */
2022
2023         dev->gc_disable = 1;
2024
2025         if (is_checkpt_block || !yaffs_still_some_chunks(dev, block)) {
2026                 T(YAFFS_TRACE_TRACING,
2027                   (TSTR
2028                    ("Collecting block %d that has no chunks in use" TENDSTR),
2029                    block));
2030                 yaffs_block_became_dirty(dev, block);
2031         } else {
2032
2033                 u8 *buffer = yaffs_get_temp_buffer(dev, __LINE__);
2034
2035                 yaffs_verify_blk(dev, bi, block);
2036
2037                 max_copies = (whole_block) ? dev->param.chunks_per_block : 5;
2038                 old_chunk = block * dev->param.chunks_per_block + dev->gc_chunk;
2039
2040                 for ( /* init already done */ ;
2041                      ret_val == YAFFS_OK &&
2042                      dev->gc_chunk < dev->param.chunks_per_block &&
2043                      (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) &&
2044                      max_copies > 0; dev->gc_chunk++, old_chunk++) {
2045                         if (yaffs_check_chunk_bit(dev, block, dev->gc_chunk)) {
2046
2047                                 /* This page is in use and might need to be copied off */
2048
2049                                 max_copies--;
2050
2051                                 mark_flash = 1;
2052
2053                                 yaffs_init_tags(&tags);
2054
2055                                 yaffs_rd_chunk_tags_nand(dev, old_chunk,
2056                                                          buffer, &tags);
2057
2058                                 object = yaffs_find_by_number(dev, tags.obj_id);
2059
2060                                 T(YAFFS_TRACE_GC_DETAIL,
2061                                   (TSTR
2062                                    ("Collecting chunk in block %d, %d %d %d "
2063                                     TENDSTR), dev->gc_chunk, tags.obj_id,
2064                                    tags.chunk_id, tags.n_bytes));
2065
2066                                 if (object && !yaffs_skip_verification(dev)) {
2067                                         if (tags.chunk_id == 0)
2068                                                 matching_chunk =
2069                                                     object->hdr_chunk;
2070                                         else if (object->soft_del)
2071                                                 matching_chunk = old_chunk;     /* Defeat the test */
2072                                         else
2073                                                 matching_chunk =
2074                                                     yaffs_find_chunk_in_file
2075                                                     (object, tags.chunk_id,
2076                                                      NULL);
2077
2078                                         if (old_chunk != matching_chunk)
2079                                                 T(YAFFS_TRACE_ERROR,
2080                                                   (TSTR
2081                                                    ("gc: page in gc mismatch: %d %d %d %d"
2082                                                     TENDSTR), old_chunk,
2083                                                    matching_chunk, tags.obj_id,
2084                                                    tags.chunk_id));
2085
2086                                 }
2087
2088                                 if (!object) {
2089                                         T(YAFFS_TRACE_ERROR,
2090                                           (TSTR
2091                                            ("page %d in gc has no object: %d %d %d "
2092                                             TENDSTR), old_chunk,
2093                                            tags.obj_id, tags.chunk_id,
2094                                            tags.n_bytes));
2095                                 }
2096
2097                                 if (object &&
2098                                     object->deleted &&
2099                                     object->soft_del && tags.chunk_id != 0) {
2100                                         /* Data chunk in a soft deleted file, throw it away
2101                                          * It's a soft deleted data chunk,
2102                                          * No need to copy this, just forget about it and
2103                                          * fix up the object.
2104                                          */
2105
2106                                         /* Free chunks already includes softdeleted chunks.
2107                                          * How ever this chunk is going to soon be really deleted
2108                                          * which will increment free chunks.
2109                                          * We have to decrement free chunks so this works out properly.
2110                                          */
2111                                         dev->n_free_chunks--;
2112                                         bi->soft_del_pages--;
2113
2114                                         object->n_data_chunks--;
2115
2116                                         if (object->n_data_chunks <= 0) {
2117                                                 /* remeber to clean up the object */
2118                                                 dev->gc_cleanup_list[dev->
2119                                                                      n_clean_ups]
2120                                                     = tags.obj_id;
2121                                                 dev->n_clean_ups++;
2122                                         }
2123                                         mark_flash = 0;
2124                                 } else if (0) {
2125                                         /* Todo object && object->deleted && object->n_data_chunks == 0 */
2126                                         /* Deleted object header with no data chunks.
2127                                          * Can be discarded and the file deleted.
2128                                          */
2129                                         object->hdr_chunk = 0;
2130                                         yaffs_free_tnode(object->my_dev,
2131                                                          object->
2132                                                          variant.file_variant.
2133                                                          top);
2134                                         object->variant.file_variant.top = NULL;
2135                                         yaffs_generic_obj_del(object);
2136
2137                                 } else if (object) {
2138                                         /* It's either a data chunk in a live file or
2139                                          * an ObjectHeader, so we're interested in it.
2140                                          * NB Need to keep the ObjectHeaders of deleted files
2141                                          * until the whole file has been deleted off
2142                                          */
2143                                         tags.serial_number++;
2144
2145                                         dev->n_gc_copies++;
2146
2147                                         if (tags.chunk_id == 0) {
2148                                                 /* It is an object Id,
2149                                                  * We need to nuke the shrinkheader flags first
2150                                                  * Also need to clean up shadowing.
2151                                                  * We no longer want the shrink_header flag since its work is done
2152                                                  * and if it is left in place it will mess up scanning.
2153                                                  */
2154
2155                                                 struct yaffs_obj_hdr *oh;
2156                                                 oh = (struct yaffs_obj_hdr *)
2157                                                     buffer;
2158
2159                                                 oh->is_shrink = 0;
2160                                                 tags.extra_is_shrink = 0;
2161
2162                                                 oh->shadows_obj = 0;
2163                                                 oh->inband_shadowed_obj_id = 0;
2164                                                 tags.extra_shadows = 0;
2165
2166                                                 /* Update file size */
2167                                                 if (object->variant_type ==
2168                                                     YAFFS_OBJECT_TYPE_FILE) {
2169                                                         oh->file_size =
2170                                                             object->variant.
2171                                                             file_variant.
2172                                                             file_size;
2173                                                         tags.extra_length =
2174                                                             oh->file_size;
2175                                                 }
2176
2177                                                 yaffs_verify_oh(object, oh,
2178                                                                 &tags, 1);
2179                                                 new_chunk =
2180                                                     yaffs_write_new_chunk(dev,
2181                                                                           (u8 *)
2182                                                                           oh,
2183                                                                           &tags,
2184                                                                           1);
2185                                         } else {
2186                                                 new_chunk =
2187                                                     yaffs_write_new_chunk(dev,
2188                                                                           buffer,
2189                                                                           &tags,
2190                                                                           1);
2191                                         }
2192
2193                                         if (new_chunk < 0) {
2194                                                 ret_val = YAFFS_FAIL;
2195                                         } else {
2196
2197                                                 /* Ok, now fix up the Tnodes etc. */
2198
2199                                                 if (tags.chunk_id == 0) {
2200                                                         /* It's a header */
2201                                                         object->hdr_chunk =
2202                                                             new_chunk;
2203                                                         object->serial =
2204                                                             tags.serial_number;
2205                                                 } else {
2206                                                         /* It's a data chunk */
2207                                                         int ok;
2208                                                         ok = yaffs_put_chunk_in_file(object, tags.chunk_id, new_chunk, 0);
2209                                                 }
2210                                         }
2211                                 }
2212
2213                                 if (ret_val == YAFFS_OK)
2214                                         yaffs_chunk_del(dev, old_chunk,
2215                                                         mark_flash, __LINE__);
2216
2217                         }
2218                 }
2219
2220                 yaffs_release_temp_buffer(dev, buffer, __LINE__);
2221
2222         }
2223
2224         yaffs_verify_collected_blk(dev, bi, block);
2225
2226         if (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
2227                 /*
2228                  * The gc did not complete. Set block state back to FULL
2229                  * because checkpointing does not restore gc.
2230                  */
2231                 bi->block_state = YAFFS_BLOCK_STATE_FULL;
2232         } else {
2233                 /* The gc completed. */
2234                 /* Do any required cleanups */
2235                 for (i = 0; i < dev->n_clean_ups; i++) {
2236                         /* Time to delete the file too */
2237                         object =
2238                             yaffs_find_by_number(dev, dev->gc_cleanup_list[i]);
2239                         if (object) {
2240                                 yaffs_free_tnode(dev,
2241                                                  object->variant.
2242                                                  file_variant.top);
2243                                 object->variant.file_variant.top = NULL;
2244                                 T(YAFFS_TRACE_GC,
2245                                   (TSTR
2246                                    ("yaffs: About to finally delete object %d"
2247                                     TENDSTR), object->obj_id));
2248                                 yaffs_generic_obj_del(object);
2249                                 object->my_dev->n_deleted_files--;
2250                         }
2251
2252                 }
2253
2254                 chunks_after = yaffs_get_erased_chunks(dev);
2255                 if (chunks_before >= chunks_after) {
2256                         T(YAFFS_TRACE_GC,
2257                           (TSTR
2258                            ("gc did not increase free chunks before %d after %d"
2259                             TENDSTR), chunks_before, chunks_after));
2260                 }
2261                 dev->gc_block = 0;
2262                 dev->gc_chunk = 0;
2263                 dev->n_clean_ups = 0;
2264         }
2265
2266         dev->gc_disable = 0;
2267
2268         return ret_val;
2269 }
2270
2271 /*
2272  * FindBlockForgarbageCollection is used to select the dirtiest block (or close enough)
2273  * for garbage collection.
2274  */
2275
2276 static unsigned yaffs_find_gc_block(struct yaffs_dev *dev,
2277                                     int aggressive, int background)
2278 {
2279         int i;
2280         int iterations;
2281         unsigned selected = 0;
2282         int prioritised = 0;
2283         int prioritised_exist = 0;
2284         struct yaffs_block_info *bi;
2285         int threshold;
2286
2287         /* First let's see if we need to grab a prioritised block */
2288         if (dev->has_pending_prioritised_gc && !aggressive) {
2289                 dev->gc_dirtiest = 0;
2290                 bi = dev->block_info;
2291                 for (i = dev->internal_start_block;
2292                      i <= dev->internal_end_block && !selected; i++) {
2293
2294                         if (bi->gc_prioritise) {
2295                                 prioritised_exist = 1;
2296                                 if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2297                                     yaffs_block_ok_for_gc(dev, bi)) {
2298                                         selected = i;
2299                                         prioritised = 1;
2300                                 }
2301                         }
2302                         bi++;
2303                 }
2304
2305                 /*
2306                  * If there is a prioritised block and none was selected then
2307                  * this happened because there is at least one old dirty block gumming
2308                  * up the works. Let's gc the oldest dirty block.
2309                  */
2310
2311                 if (prioritised_exist &&
2312                     !selected && dev->oldest_dirty_block > 0)
2313                         selected = dev->oldest_dirty_block;
2314
2315                 if (!prioritised_exist) /* None found, so we can clear this */
2316                         dev->has_pending_prioritised_gc = 0;
2317         }
2318
2319         /* If we're doing aggressive GC then we are happy to take a less-dirty block, and
2320          * search harder.
2321          * else (we're doing a leasurely gc), then we only bother to do this if the
2322          * block has only a few pages in use.
2323          */
2324
2325         if (!selected) {
2326                 int pages_used;
2327                 int n_blocks =
2328                     dev->internal_end_block - dev->internal_start_block + 1;
2329                 if (aggressive) {
2330                         threshold = dev->param.chunks_per_block;
2331                         iterations = n_blocks;
2332                 } else {
2333                         int max_threshold;
2334
2335                         if (background)
2336                                 max_threshold = dev->param.chunks_per_block / 2;
2337                         else
2338                                 max_threshold = dev->param.chunks_per_block / 8;
2339
2340                         if (max_threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2341                                 max_threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2342
2343                         threshold = background ? (dev->gc_not_done + 2) * 2 : 0;
2344                         if (threshold < YAFFS_GC_PASSIVE_THRESHOLD)
2345                                 threshold = YAFFS_GC_PASSIVE_THRESHOLD;
2346                         if (threshold > max_threshold)
2347                                 threshold = max_threshold;
2348
2349                         iterations = n_blocks / 16 + 1;
2350                         if (iterations > 100)
2351                                 iterations = 100;
2352                 }
2353
2354                 for (i = 0;
2355                      i < iterations &&
2356                      (dev->gc_dirtiest < 1 ||
2357                       dev->gc_pages_in_use > YAFFS_GC_GOOD_ENOUGH); i++) {
2358                         dev->gc_block_finder++;
2359                         if (dev->gc_block_finder < dev->internal_start_block ||
2360                             dev->gc_block_finder > dev->internal_end_block)
2361                                 dev->gc_block_finder =
2362                                     dev->internal_start_block;
2363
2364                         bi = yaffs_get_block_info(dev, dev->gc_block_finder);
2365
2366                         pages_used = bi->pages_in_use - bi->soft_del_pages;
2367
2368                         if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
2369                             pages_used < dev->param.chunks_per_block &&
2370                             (dev->gc_dirtiest < 1
2371                              || pages_used < dev->gc_pages_in_use)
2372                             && yaffs_block_ok_for_gc(dev, bi)) {
2373                                 dev->gc_dirtiest = dev->gc_block_finder;
2374                                 dev->gc_pages_in_use = pages_used;
2375                         }
2376                 }
2377
2378                 if (dev->gc_dirtiest > 0 && dev->gc_pages_in_use <= threshold)
2379                         selected = dev->gc_dirtiest;
2380         }
2381
2382         /*
2383          * If nothing has been selected for a while, try selecting the oldest dirty
2384          * because that's gumming up the works.
2385          */
2386
2387         if (!selected && dev->param.is_yaffs2 &&
2388             dev->gc_not_done >= (background ? 10 : 20)) {
2389                 yaffs2_find_oldest_dirty_seq(dev);
2390                 if (dev->oldest_dirty_block > 0) {
2391                         selected = dev->oldest_dirty_block;
2392                         dev->gc_dirtiest = selected;
2393                         dev->oldest_dirty_gc_count++;
2394                         bi = yaffs_get_block_info(dev, selected);
2395                         dev->gc_pages_in_use =
2396                             bi->pages_in_use - bi->soft_del_pages;
2397                 } else {
2398                         dev->gc_not_done = 0;
2399                 }
2400         }
2401
2402         if (selected) {
2403                 T(YAFFS_TRACE_GC,
2404                   (TSTR
2405                    ("GC Selected block %d with %d free, prioritised:%d"
2406                     TENDSTR), selected,
2407                    dev->param.chunks_per_block - dev->gc_pages_in_use,
2408                    prioritised));
2409
2410                 dev->n_gc_blocks++;
2411                 if (background)
2412                         dev->bg_gcs++;
2413
2414                 dev->gc_dirtiest = 0;
2415                 dev->gc_pages_in_use = 0;
2416                 dev->gc_not_done = 0;
2417                 if (dev->refresh_skip > 0)
2418                         dev->refresh_skip--;
2419         } else {
2420                 dev->gc_not_done++;
2421                 T(YAFFS_TRACE_GC,
2422                   (TSTR
2423                    ("GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s"
2424                     TENDSTR), dev->gc_block_finder, dev->gc_not_done, threshold,
2425                    dev->gc_dirtiest, dev->gc_pages_in_use,
2426                    dev->oldest_dirty_block, background ? " bg" : ""));
2427         }
2428
2429         return selected;
2430 }
2431
2432 /* New garbage collector
2433  * If we're very low on erased blocks then we do aggressive garbage collection
2434  * otherwise we do "leasurely" garbage collection.
2435  * Aggressive gc looks further (whole array) and will accept less dirty blocks.
2436  * Passive gc only inspects smaller areas and will only accept more dirty blocks.
2437  *
2438  * The idea is to help clear out space in a more spread-out manner.
2439  * Dunno if it really does anything useful.
2440  */
2441 static int yaffs_check_gc(struct yaffs_dev *dev, int background)
2442 {
2443         int aggressive = 0;
2444         int gc_ok = YAFFS_OK;
2445         int max_tries = 0;
2446         int min_erased;
2447         int erased_chunks;
2448         int checkpt_block_adjust;
2449
2450         if (dev->param.gc_control && (dev->param.gc_control(dev) & 1) == 0)
2451                 return YAFFS_OK;
2452
2453         if (dev->gc_disable) {
2454                 /* Bail out so we don't get recursive gc */
2455                 return YAFFS_OK;
2456         }
2457
2458         /* This loop should pass the first time.
2459          * We'll only see looping here if the collection does not increase space.
2460          */
2461
2462         do {
2463                 max_tries++;
2464
2465                 checkpt_block_adjust = yaffs_calc_checkpt_blocks_required(dev);
2466
2467                 min_erased =
2468                     dev->param.n_reserved_blocks + checkpt_block_adjust + 1;
2469                 erased_chunks =
2470                     dev->n_erased_blocks * dev->param.chunks_per_block;
2471
2472                 /* If we need a block soon then do aggressive gc. */
2473                 if (dev->n_erased_blocks < min_erased)
2474                         aggressive = 1;
2475                 else {
2476                         if (!background
2477                             && erased_chunks > (dev->n_free_chunks / 4))
2478                                 break;
2479
2480                         if (dev->gc_skip > 20)
2481                                 dev->gc_skip = 20;
2482                         if (erased_chunks < dev->n_free_chunks / 2 ||
2483                             dev->gc_skip < 1 || background)
2484                                 aggressive = 0;
2485                         else {
2486                                 dev->gc_skip--;
2487                                 break;
2488                         }
2489                 }
2490
2491                 dev->gc_skip = 5;
2492
2493                 /* If we don't already have a block being gc'd then see if we should start another */
2494
2495                 if (dev->gc_block < 1 && !aggressive) {
2496                         dev->gc_block = yaffs2_find_refresh_block(dev);
2497                         dev->gc_chunk = 0;
2498                         dev->n_clean_ups = 0;
2499                 }
2500                 if (dev->gc_block < 1) {
2501                         dev->gc_block =
2502                             yaffs_find_gc_block(dev, aggressive, background);
2503                         dev->gc_chunk = 0;
2504                         dev->n_clean_ups = 0;
2505                 }
2506
2507                 if (dev->gc_block > 0) {
2508                         dev->all_gcs++;
2509                         if (!aggressive)
2510                                 dev->passive_gc_count++;
2511
2512                         T(YAFFS_TRACE_GC,
2513                           (TSTR
2514                            ("yaffs: GC n_erased_blocks %d aggressive %d"
2515                             TENDSTR), dev->n_erased_blocks, aggressive));
2516
2517                         gc_ok = yaffs_gc_block(dev, dev->gc_block, aggressive);
2518                 }
2519
2520                 if (dev->n_erased_blocks < (dev->param.n_reserved_blocks)
2521                     && dev->gc_block > 0) {
2522                         T(YAFFS_TRACE_GC,
2523                           (TSTR
2524                            ("yaffs: GC !!!no reclaim!!! n_erased_blocks %d after try %d block %d"
2525                             TENDSTR), dev->n_erased_blocks, max_tries,
2526                            dev->gc_block));
2527                 }
2528         } while ((dev->n_erased_blocks < dev->param.n_reserved_blocks) &&
2529                  (dev->gc_block > 0) && (max_tries < 2));
2530
2531         return aggressive ? gc_ok : YAFFS_OK;
2532 }
2533
2534 /*
2535  * yaffs_bg_gc()
2536  * Garbage collects. Intended to be called from a background thread.
2537  * Returns non-zero if at least half the free chunks are erased.
2538  */
2539 int yaffs_bg_gc(struct yaffs_dev *dev, unsigned urgency)
2540 {
2541         int erased_chunks = dev->n_erased_blocks * dev->param.chunks_per_block;
2542
2543         T(YAFFS_TRACE_BACKGROUND, (TSTR("Background gc %u" TENDSTR), urgency));
2544
2545         yaffs_check_gc(dev, 1);
2546         return erased_chunks > dev->n_free_chunks / 2;
2547 }
2548
2549 /*-------------------------  TAGS --------------------------------*/
2550
2551 static int yaffs_tags_match(const struct yaffs_ext_tags *tags, int obj_id,
2552                             int chunk_obj)
2553 {
2554         return (tags->chunk_id == chunk_obj &&
2555                 tags->obj_id == obj_id && !tags->is_deleted) ? 1 : 0;
2556
2557 }
2558
2559 /*-------------------- Data file manipulation -----------------*/
2560
2561 static int yaffs_find_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
2562                                     struct yaffs_ext_tags *tags)
2563 {
2564         /*Get the Tnode, then get the level 0 offset chunk offset */
2565         struct yaffs_tnode *tn;
2566         int the_chunk = -1;
2567         struct yaffs_ext_tags local_tags;
2568         int ret_val = -1;
2569
2570         struct yaffs_dev *dev = in->my_dev;
2571
2572         if (!tags) {
2573                 /* Passed a NULL, so use our own tags space */
2574                 tags = &local_tags;
2575         }
2576
2577         tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
2578
2579         if (tn) {
2580                 the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);
2581
2582                 ret_val =
2583                     yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
2584                                               inode_chunk);
2585         }
2586         return ret_val;
2587 }
2588
2589 static int yaffs_find_del_file_chunk(struct yaffs_obj *in, int inode_chunk,
2590                                      struct yaffs_ext_tags *tags)
2591 {
2592         /* Get the Tnode, then get the level 0 offset chunk offset */
2593         struct yaffs_tnode *tn;
2594         int the_chunk = -1;
2595         struct yaffs_ext_tags local_tags;
2596
2597         struct yaffs_dev *dev = in->my_dev;
2598         int ret_val = -1;
2599
2600         if (!tags) {
2601                 /* Passed a NULL, so use our own tags space */
2602                 tags = &local_tags;
2603         }
2604
2605         tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
2606
2607         if (tn) {
2608
2609                 the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);
2610
2611                 ret_val =
2612                     yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
2613                                               inode_chunk);
2614
2615                 /* Delete the entry in the filestructure (if found) */
2616                 if (ret_val != -1)
2617                         yaffs_load_tnode_0(dev, tn, inode_chunk, 0);
2618         }
2619
2620         return ret_val;
2621 }
2622
2623 int yaffs_put_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
2624                             int nand_chunk, int in_scan)
2625 {
2626         /* NB in_scan is zero unless scanning.
2627          * For forward scanning, in_scan is > 0;
2628          * for backward scanning in_scan is < 0
2629          *
2630          * nand_chunk = 0 is a dummy insert to make sure the tnodes are there.
2631          */
2632
2633         struct yaffs_tnode *tn;
2634         struct yaffs_dev *dev = in->my_dev;
2635         int existing_cunk;
2636         struct yaffs_ext_tags existing_tags;
2637         struct yaffs_ext_tags new_tags;
2638         unsigned existing_serial, new_serial;
2639
2640         if (in->variant_type != YAFFS_OBJECT_TYPE_FILE) {
2641                 /* Just ignore an attempt at putting a chunk into a non-file during scanning
2642                  * If it is not during Scanning then something went wrong!
2643                  */
2644                 if (!in_scan) {
2645                         T(YAFFS_TRACE_ERROR,
2646                           (TSTR
2647                            ("yaffs tragedy:attempt to put data chunk into a non-file"
2648                             TENDSTR)));
2649                         YBUG();
2650                 }
2651
2652                 yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
2653                 return YAFFS_OK;
2654         }
2655
2656         tn = yaffs_add_find_tnode_0(dev,
2657                                     &in->variant.file_variant,
2658                                     inode_chunk, NULL);
2659         if (!tn)
2660                 return YAFFS_FAIL;
2661
2662         if (!nand_chunk)
2663                 /* Dummy insert, bail now */
2664                 return YAFFS_OK;
2665
2666         existing_cunk = yaffs_get_group_base(dev, tn, inode_chunk);
2667
2668         if (in_scan != 0) {
2669                 /* If we're scanning then we need to test for duplicates
2670                  * NB This does not need to be efficient since it should only ever
2671                  * happen when the power fails during a write, then only one
2672                  * chunk should ever be affected.
2673                  *
2674                  * Correction for YAFFS2: This could happen quite a lot and we need to think about efficiency! TODO
2675                  * Update: For backward scanning we don't need to re-read tags so this is quite cheap.
2676                  */
2677
2678                 if (existing_cunk > 0) {
2679                         /* NB Right now existing chunk will not be real chunk_id if the chunk group size > 1
2680                          *    thus we have to do a FindChunkInFile to get the real chunk id.
2681                          *
2682                          * We have a duplicate now we need to decide which one to use:
2683                          *
2684                          * Backwards scanning YAFFS2: The old one is what we use, dump the new one.
2685                          * Forward scanning YAFFS2: The new one is what we use, dump the old one.
2686                          * YAFFS1: Get both sets of tags and compare serial numbers.
2687                          */
2688
2689                         if (in_scan > 0) {
2690                                 /* Only do this for forward scanning */
2691                                 yaffs_rd_chunk_tags_nand(dev,
2692                                                          nand_chunk,
2693                                                          NULL, &new_tags);
2694
2695                                 /* Do a proper find */
2696                                 existing_cunk =
2697                                     yaffs_find_chunk_in_file(in, inode_chunk,
2698                                                              &existing_tags);
2699                         }
2700
2701                         if (existing_cunk <= 0) {
2702                                 /*Hoosterman - how did this happen? */
2703
2704                                 T(YAFFS_TRACE_ERROR,
2705                                   (TSTR
2706                                    ("yaffs tragedy: existing chunk < 0 in scan"
2707                                     TENDSTR)));
2708
2709                         }
2710
2711                         /* NB The deleted flags should be false, otherwise the chunks will
2712                          * not be loaded during a scan
2713                          */
2714
2715                         if (in_scan > 0) {
2716                                 new_serial = new_tags.serial_number;
2717                                 existing_serial = existing_tags.serial_number;
2718                         }
2719
2720                         if ((in_scan > 0) &&
2721                             (existing_cunk <= 0 ||
2722                              ((existing_serial + 1) & 3) == new_serial)) {
2723                                 /* Forward scanning.
2724                                  * Use new
2725                                  * Delete the old one and drop through to update the tnode
2726                                  */
2727                                 yaffs_chunk_del(dev, existing_cunk, 1,
2728                                                 __LINE__);
2729                         } else {
2730                                 /* Backward scanning or we want to use the existing one
2731                                  * Use existing.
2732                                  * Delete the new one and return early so that the tnode isn't changed
2733                                  */
2734                                 yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
2735                                 return YAFFS_OK;
2736                         }
2737                 }
2738
2739         }
2740
2741         if (existing_cunk == 0)
2742                 in->n_data_chunks++;
2743
2744         yaffs_load_tnode_0(dev, tn, inode_chunk, nand_chunk);
2745
2746         return YAFFS_OK;
2747 }
2748
2749 static int yaffs_rd_data_obj(struct yaffs_obj *in, int inode_chunk, u8 * buffer)
2750 {
2751         int nand_chunk = yaffs_find_chunk_in_file(in, inode_chunk, NULL);
2752
2753         if (nand_chunk >= 0)
2754                 return yaffs_rd_chunk_tags_nand(in->my_dev, nand_chunk,
2755                                                 buffer, NULL);
2756         else {
2757                 T(YAFFS_TRACE_NANDACCESS,
2758                   (TSTR("Chunk %d not found zero instead" TENDSTR),
2759                    nand_chunk));
2760                 /* get sane (zero) data if you read a hole */
2761                 memset(buffer, 0, in->my_dev->data_bytes_per_chunk);
2762                 return 0;
2763         }
2764
2765 }
2766
2767 void yaffs_chunk_del(struct yaffs_dev *dev, int chunk_id, int mark_flash,
2768                      int lyn)
2769 {
2770         int block;
2771         int page;
2772         struct yaffs_ext_tags tags;
2773         struct yaffs_block_info *bi;
2774
2775         if (chunk_id <= 0)
2776                 return;
2777
2778         dev->n_deletions++;
2779         block = chunk_id / dev->param.chunks_per_block;
2780         page = chunk_id % dev->param.chunks_per_block;
2781
2782         if (!yaffs_check_chunk_bit(dev, block, page))
2783                 T(YAFFS_TRACE_VERIFY,
2784                   (TSTR("Deleting invalid chunk %d" TENDSTR), chunk_id));
2785
2786         bi = yaffs_get_block_info(dev, block);
2787
2788         yaffs2_update_oldest_dirty_seq(dev, block, bi);
2789
2790         T(YAFFS_TRACE_DELETION,
2791           (TSTR("line %d delete of chunk %d" TENDSTR), lyn, chunk_id));
2792
2793         if (!dev->param.is_yaffs2 && mark_flash &&
2794             bi->block_state != YAFFS_BLOCK_STATE_COLLECTING) {
2795
2796                 yaffs_init_tags(&tags);
2797
2798                 tags.is_deleted = 1;
2799
2800                 yaffs_wr_chunk_tags_nand(dev, chunk_id, NULL, &tags);
2801                 yaffs_handle_chunk_update(dev, chunk_id, &tags);
2802         } else {
2803                 dev->n_unmarked_deletions++;
2804         }
2805
2806         /* Pull out of the management area.
2807          * If the whole block became dirty, this will kick off an erasure.
2808          */
2809         if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING ||
2810             bi->block_state == YAFFS_BLOCK_STATE_FULL ||
2811             bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCANNING ||
2812             bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
2813                 dev->n_free_chunks++;
2814
2815                 yaffs_clear_chunk_bit(dev, block, page);
2816
2817                 bi->pages_in_use--;
2818
2819                 if (bi->pages_in_use == 0 &&
2820                     !bi->has_shrink_hdr &&
2821                     bi->block_state != YAFFS_BLOCK_STATE_ALLOCATING &&
2822                     bi->block_state != YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
2823                         yaffs_block_became_dirty(dev, block);
2824                 }
2825
2826         }
2827
2828 }
2829
2830 static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
2831                              const u8 * buffer, int n_bytes, int use_reserve)
2832 {
2833         /* Find old chunk Need to do this to get serial number
2834          * Write new one and patch into tree.
2835          * Invalidate old tags.
2836          */
2837
2838         int prev_chunk_id;
2839         struct yaffs_ext_tags prev_tags;
2840
2841         int new_chunk_id;
2842         struct yaffs_ext_tags new_tags;
2843
2844         struct yaffs_dev *dev = in->my_dev;
2845
2846         yaffs_check_gc(dev, 0);
2847
2848         /* Get the previous chunk at this location in the file if it exists.
2849          * If it does not exist then put a zero into the tree. This creates
2850          * the tnode now, rather than later when it is harder to clean up.
2851          */
2852         prev_chunk_id = yaffs_find_chunk_in_file(in, inode_chunk, &prev_tags);
2853         if (prev_chunk_id < 1 &&
2854             !yaffs_put_chunk_in_file(in, inode_chunk, 0, 0))
2855                 return 0;
2856
2857         /* Set up new tags */
2858         yaffs_init_tags(&new_tags);
2859
2860         new_tags.chunk_id = inode_chunk;
2861         new_tags.obj_id = in->obj_id;
2862         new_tags.serial_number =
2863             (prev_chunk_id > 0) ? prev_tags.serial_number + 1 : 1;
2864         new_tags.n_bytes = n_bytes;
2865
2866         if (n_bytes < 1 || n_bytes > dev->param.total_bytes_per_chunk) {
2867                 T(YAFFS_TRACE_ERROR,
2868                   (TSTR("Writing %d bytes to chunk!!!!!!!!!" TENDSTR),
2869                    n_bytes));
2870                 YBUG();
2871         }
2872
2873         new_chunk_id =
2874             yaffs_write_new_chunk(dev, buffer, &new_tags, use_reserve);
2875
2876         if (new_chunk_id > 0) {
2877                 yaffs_put_chunk_in_file(in, inode_chunk, new_chunk_id, 0);
2878
2879                 if (prev_chunk_id > 0)
2880                         yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
2881
2882                 yaffs_verify_file_sane(in);
2883         }
2884         return new_chunk_id;
2885
2886 }
2887
2888 /* UpdateObjectHeader updates the header on NAND for an object.
2889  * If name is not NULL, then that new name is used.
2890  */
2891 int yaffs_update_oh(struct yaffs_obj *in, const YCHAR * name, int force,
2892                     int is_shrink, int shadows, struct yaffs_xattr_mod *xmod)
2893 {
2894
2895         struct yaffs_block_info *bi;
2896
2897         struct yaffs_dev *dev = in->my_dev;
2898
2899         int prev_chunk_id;
2900         int ret_val = 0;
2901         int result = 0;
2902
2903         int new_chunk_id;
2904         struct yaffs_ext_tags new_tags;
2905         struct yaffs_ext_tags old_tags;
2906         const YCHAR *alias = NULL;
2907
2908         u8 *buffer = NULL;
2909         YCHAR old_name[YAFFS_MAX_NAME_LENGTH + 1];
2910
2911         struct yaffs_obj_hdr *oh = NULL;
2912
2913         yaffs_strcpy(old_name, _Y("silly old name"));
2914
2915         if (!in->fake || in == dev->root_dir || /* The root_dir should also be saved */
2916             force || xmod) {
2917
2918                 yaffs_check_gc(dev, 0);
2919                 yaffs_check_obj_details_loaded(in);
2920
2921                 buffer = yaffs_get_temp_buffer(in->my_dev, __LINE__);
2922                 oh = (struct yaffs_obj_hdr *)buffer;
2923
2924                 prev_chunk_id = in->hdr_chunk;
2925
2926                 if (prev_chunk_id > 0) {
2927                         result = yaffs_rd_chunk_tags_nand(dev, prev_chunk_id,
2928                                                           buffer, &old_tags);
2929
2930                         yaffs_verify_oh(in, oh, &old_tags, 0);
2931
2932                         memcpy(old_name, oh->name, sizeof(oh->name));
2933                         memset(buffer, 0xFF, sizeof(struct yaffs_obj_hdr));
2934                 } else {
2935                         memset(buffer, 0xFF, dev->data_bytes_per_chunk);
2936                 }
2937
2938                 oh->type = in->variant_type;
2939                 oh->yst_mode = in->yst_mode;
2940                 oh->shadows_obj = oh->inband_shadowed_obj_id = shadows;
2941
2942                 yaffs_load_attribs_oh(oh, in);
2943
2944                 if (in->parent)
2945                         oh->parent_obj_id = in->parent->obj_id;
2946                 else
2947                         oh->parent_obj_id = 0;
2948
2949                 if (name && *name) {
2950                         memset(oh->name, 0, sizeof(oh->name));
2951                         yaffs_load_oh_from_name(dev, oh->name, name);
2952                 } else if (prev_chunk_id > 0) {
2953                         memcpy(oh->name, old_name, sizeof(oh->name));
2954                 } else {
2955                         memset(oh->name, 0, sizeof(oh->name));
2956                 }
2957
2958                 oh->is_shrink = is_shrink;
2959
2960                 switch (in->variant_type) {
2961                 case YAFFS_OBJECT_TYPE_UNKNOWN:
2962                         /* Should not happen */
2963                         break;
2964                 case YAFFS_OBJECT_TYPE_FILE:
2965                         oh->file_size =
2966                             (oh->parent_obj_id == YAFFS_OBJECTID_DELETED
2967                              || oh->parent_obj_id ==
2968                              YAFFS_OBJECTID_UNLINKED) ? 0 : in->
2969                             variant.file_variant.file_size;
2970                         break;
2971                 case YAFFS_OBJECT_TYPE_HARDLINK:
2972                         oh->equiv_id = in->variant.hardlink_variant.equiv_id;
2973                         break;
2974                 case YAFFS_OBJECT_TYPE_SPECIAL:
2975                         /* Do nothing */
2976                         break;
2977                 case YAFFS_OBJECT_TYPE_DIRECTORY:
2978                         /* Do nothing */
2979                         break;
2980                 case YAFFS_OBJECT_TYPE_SYMLINK:
2981                         alias = in->variant.symlink_variant.alias;
2982                         if (!alias)
2983                                 alias = _Y("no alias");
2984                         yaffs_strncpy(oh->alias, alias, YAFFS_MAX_ALIAS_LENGTH);
2985                         oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
2986                         break;
2987                 }
2988
2989                 /* process any xattrib modifications */
2990                 if (xmod)
2991                         yaffs_apply_xattrib_mod(in, (char *)buffer, xmod);
2992
2993                 /* Tags */
2994                 yaffs_init_tags(&new_tags);
2995                 in->serial++;
2996                 new_tags.chunk_id = 0;
2997                 new_tags.obj_id = in->obj_id;
2998                 new_tags.serial_number = in->serial;
2999
3000                 /* Add extra info for file header */
3001
3002                 new_tags.extra_available = 1;
3003                 new_tags.extra_parent_id = oh->parent_obj_id;
3004                 new_tags.extra_length = oh->file_size;
3005                 new_tags.extra_is_shrink = oh->is_shrink;
3006                 new_tags.extra_equiv_id = oh->equiv_id;
3007                 new_tags.extra_shadows = (oh->shadows_obj > 0) ? 1 : 0;
3008                 new_tags.extra_obj_type = in->variant_type;
3009
3010                 yaffs_verify_oh(in, oh, &new_tags, 1);
3011
3012                 /* Create new chunk in NAND */
3013                 new_chunk_id =
3014                     yaffs_write_new_chunk(dev, buffer, &new_tags,
3015                                           (prev_chunk_id > 0) ? 1 : 0);
3016
3017                 if (new_chunk_id >= 0) {
3018
3019                         in->hdr_chunk = new_chunk_id;
3020
3021                         if (prev_chunk_id > 0) {
3022                                 yaffs_chunk_del(dev, prev_chunk_id, 1,
3023                                                 __LINE__);
3024                         }
3025
3026                         if (!yaffs_obj_cache_dirty(in))
3027                                 in->dirty = 0;
3028
3029                         /* If this was a shrink, then mark the block that the chunk lives on */
3030                         if (is_shrink) {
3031                                 bi = yaffs_get_block_info(in->my_dev,
3032                                                           new_chunk_id /
3033                                                           in->my_dev->param.
3034                                                           chunks_per_block);
3035                                 bi->has_shrink_hdr = 1;
3036                         }
3037
3038                 }
3039
3040                 ret_val = new_chunk_id;
3041
3042         }
3043
3044         if (buffer)
3045                 yaffs_release_temp_buffer(dev, buffer, __LINE__);
3046
3047         return ret_val;
3048 }
3049
3050 /*------------------------ Short Operations Cache ----------------------------------------
3051  *   In many situations where there is no high level buffering  a lot of
3052  *   reads might be short sequential reads, and a lot of writes may be short
3053  *   sequential writes. eg. scanning/writing a jpeg file.
3054  *   In these cases, a short read/write cache can provide a huge perfomance
3055  *   benefit with dumb-as-a-rock code.
3056  *   In Linux, the page cache provides read buffering and the short op cache 
3057  *   provides write buffering.
3058  *
3059  *   There are a limited number (~10) of cache chunks per device so that we don't
3060  *   need a very intelligent search.
3061  */
3062
3063 static int yaffs_obj_cache_dirty(struct yaffs_obj *obj)
3064 {
3065         struct yaffs_dev *dev = obj->my_dev;
3066         int i;
3067         struct yaffs_cache *cache;
3068         int n_caches = obj->my_dev->param.n_caches;
3069
3070         for (i = 0; i < n_caches; i++) {
3071                 cache = &dev->cache[i];
3072                 if (cache->object == obj && cache->dirty)
3073                         return 1;
3074         }
3075
3076         return 0;
3077 }
3078
3079 static void yaffs_flush_file_cache(struct yaffs_obj *obj)
3080 {
3081         struct yaffs_dev *dev = obj->my_dev;
3082         int lowest = -99;       /* Stop compiler whining. */
3083         int i;
3084         struct yaffs_cache *cache;
3085         int chunk_written = 0;
3086         int n_caches = obj->my_dev->param.n_caches;
3087
3088         if (n_caches > 0) {
3089                 do {
3090                         cache = NULL;
3091
3092                         /* Find the dirty cache for this object with the lowest chunk id. */
3093                         for (i = 0; i < n_caches; i++) {
3094                                 if (dev->cache[i].object == obj &&
3095                                     dev->cache[i].dirty) {
3096                                         if (!cache
3097                                             || dev->cache[i].chunk_id <
3098                                             lowest) {
3099                                                 cache = &dev->cache[i];
3100                                                 lowest = cache->chunk_id;
3101                                         }
3102                                 }
3103                         }
3104
3105                         if (cache && !cache->locked) {
3106                                 /* Write it out and free it up */
3107
3108                                 chunk_written =
3109                                     yaffs_wr_data_obj(cache->object,
3110                                                       cache->chunk_id,
3111                                                       cache->data,
3112                                                       cache->n_bytes, 1);
3113                                 cache->dirty = 0;
3114                                 cache->object = NULL;
3115                         }
3116
3117                 } while (cache && chunk_written > 0);
3118
3119                 if (cache) {
3120                         /* Hoosterman, disk full while writing cache out. */
3121                         T(YAFFS_TRACE_ERROR,
3122                           (TSTR
3123                            ("yaffs tragedy: no space during cache write"
3124                             TENDSTR)));
3125
3126                 }
3127         }
3128
3129 }
3130
3131 /*yaffs_flush_whole_cache(dev)
3132  *
3133  *
3134  */
3135
3136 void yaffs_flush_whole_cache(struct yaffs_dev *dev)
3137 {
3138         struct yaffs_obj *obj;
3139         int n_caches = dev->param.n_caches;
3140         int i;
3141
3142         /* Find a dirty object in the cache and flush it...
3143          * until there are no further dirty objects.
3144          */
3145         do {
3146                 obj = NULL;
3147                 for (i = 0; i < n_caches && !obj; i++) {
3148                         if (dev->cache[i].object && dev->cache[i].dirty)
3149                                 obj = dev->cache[i].object;
3150
3151                 }
3152                 if (obj)
3153                         yaffs_flush_file_cache(obj);
3154
3155         } while (obj);
3156
3157 }
3158
3159 /* Grab us a cache chunk for use.
3160  * First look for an empty one.
3161  * Then look for the least recently used non-dirty one.
3162  * Then look for the least recently used dirty one...., flush and look again.
3163  */
3164 static struct yaffs_cache *yaffs_grab_chunk_worker(struct yaffs_dev *dev)
3165 {
3166         int i;
3167
3168         if (dev->param.n_caches > 0) {
3169                 for (i = 0; i < dev->param.n_caches; i++) {
3170                         if (!dev->cache[i].object)
3171                                 return &dev->cache[i];
3172                 }
3173         }
3174
3175         return NULL;
3176 }
3177
3178 static struct yaffs_cache *yaffs_grab_chunk_cache(struct yaffs_dev *dev)
3179 {
3180         struct yaffs_cache *cache;
3181         struct yaffs_obj *the_obj;
3182         int usage;
3183         int i;
3184         int pushout;
3185
3186         if (dev->param.n_caches > 0) {
3187                 /* Try find a non-dirty one... */
3188
3189                 cache = yaffs_grab_chunk_worker(dev);
3190
3191                 if (!cache) {
3192                         /* They were all dirty, find the last recently used object and flush
3193                          * its cache, then  find again.
3194                          * NB what's here is not very accurate, we actually flush the object
3195                          * the last recently used page.
3196                          */
3197
3198                         /* With locking we can't assume we can use entry zero */
3199
3200                         the_obj = NULL;
3201                         usage = -1;
3202                         cache = NULL;
3203                         pushout = -1;
3204
3205                         for (i = 0; i < dev->param.n_caches; i++) {
3206                                 if (dev->cache[i].object &&
3207                                     !dev->cache[i].locked &&
3208                                     (dev->cache[i].last_use < usage
3209                                      || !cache)) {
3210                                         usage = dev->cache[i].last_use;
3211                                         the_obj = dev->cache[i].object;
3212                                         cache = &dev->cache[i];
3213                                         pushout = i;
3214                                 }
3215                         }
3216
3217                         if (!cache || cache->dirty) {
3218                                 /* Flush and try again */
3219                                 yaffs_flush_file_cache(the_obj);
3220                                 cache = yaffs_grab_chunk_worker(dev);
3221                         }
3222
3223                 }
3224                 return cache;
3225         } else {
3226                 return NULL;
3227         }
3228 }
3229
3230 /* Find a cached chunk */
3231 static struct yaffs_cache *yaffs_find_chunk_cache(const struct yaffs_obj *obj,
3232                                                   int chunk_id)
3233 {
3234         struct yaffs_dev *dev = obj->my_dev;
3235         int i;
3236         if (dev->param.n_caches > 0) {
3237                 for (i = 0; i < dev->param.n_caches; i++) {
3238                         if (dev->cache[i].object == obj &&
3239                             dev->cache[i].chunk_id == chunk_id) {
3240                                 dev->cache_hits++;
3241
3242                                 return &dev->cache[i];
3243                         }
3244                 }
3245         }
3246         return NULL;
3247 }
3248
3249 /* Mark the chunk for the least recently used algorithym */
3250 static void yaffs_use_cache(struct yaffs_dev *dev, struct yaffs_cache *cache,
3251                             int is_write)
3252 {
3253
3254         if (dev->param.n_caches > 0) {
3255                 if (dev->cache_last_use < 0 || dev->cache_last_use > 100000000) {
3256                         /* Reset the cache usages */
3257                         int i;
3258                         for (i = 1; i < dev->param.n_caches; i++)
3259                                 dev->cache[i].last_use = 0;
3260
3261                         dev->cache_last_use = 0;
3262                 }
3263
3264                 dev->cache_last_use++;
3265
3266                 cache->last_use = dev->cache_last_use;
3267
3268                 if (is_write)
3269                         cache->dirty = 1;
3270         }
3271 }
3272
3273 /* Invalidate a single cache page.
3274  * Do this when a whole page gets written,
3275  * ie the short cache for this page is no longer valid.
3276  */
3277 static void yaffs_invalidate_chunk_cache(struct yaffs_obj *object, int chunk_id)
3278 {
3279         if (object->my_dev->param.n_caches > 0) {
3280                 struct yaffs_cache *cache =
3281                     yaffs_find_chunk_cache(object, chunk_id);
3282
3283                 if (cache)
3284                         cache->object = NULL;
3285         }
3286 }
3287
3288 /* Invalidate all the cache pages associated with this object
3289  * Do this whenever ther file is deleted or resized.
3290  */
3291 static void yaffs_invalidate_whole_cache(struct yaffs_obj *in)
3292 {
3293         int i;
3294         struct yaffs_dev *dev = in->my_dev;
3295
3296         if (dev->param.n_caches > 0) {
3297                 /* Invalidate it. */
3298                 for (i = 0; i < dev->param.n_caches; i++) {
3299                         if (dev->cache[i].object == in)
3300                                 dev->cache[i].object = NULL;
3301                 }
3302         }
3303 }
3304
3305 /*--------------------- File read/write ------------------------
3306  * Read and write have very similar structures.
3307  * In general the read/write has three parts to it
3308  * An incomplete chunk to start with (if the read/write is not chunk-aligned)
3309  * Some complete chunks
3310  * An incomplete chunk to end off with
3311  *
3312  * Curve-balls: the first chunk might also be the last chunk.
3313  */
3314
3315 int yaffs_file_rd(struct yaffs_obj *in, u8 * buffer, loff_t offset, int n_bytes)
3316 {
3317
3318         int chunk;
3319         u32 start;
3320         int n_copy;
3321         int n = n_bytes;
3322         int n_done = 0;
3323         struct yaffs_cache *cache;
3324
3325         struct yaffs_dev *dev;
3326
3327         dev = in->my_dev;
3328
3329         while (n > 0) {
3330                 /* chunk = offset / dev->data_bytes_per_chunk + 1; */
3331                 /* start = offset % dev->data_bytes_per_chunk; */
3332                 yaffs_addr_to_chunk(dev, offset, &chunk, &start);
3333                 chunk++;
3334
3335                 /* OK now check for the curveball where the start and end are in
3336                  * the same chunk.
3337                  */
3338                 if ((start + n) < dev->data_bytes_per_chunk)
3339                         n_copy = n;
3340                 else
3341                         n_copy = dev->data_bytes_per_chunk - start;
3342
3343                 cache = yaffs_find_chunk_cache(in, chunk);
3344
3345                 /* If the chunk is already in the cache or it is less than a whole chunk
3346                  * or we're using inband tags then use the cache (if there is caching)
3347                  * else bypass the cache.
3348                  */
3349                 if (cache || n_copy != dev->data_bytes_per_chunk
3350                     || dev->param.inband_tags) {
3351                         if (dev->param.n_caches > 0) {
3352
3353                                 /* If we can't find the data in the cache, then load it up. */
3354
3355                                 if (!cache) {
3356                                         cache =
3357                                             yaffs_grab_chunk_cache(in->my_dev);
3358                                         cache->object = in;
3359                                         cache->chunk_id = chunk;
3360                                         cache->dirty = 0;
3361                                         cache->locked = 0;
3362                                         yaffs_rd_data_obj(in, chunk,
3363                                                           cache->data);
3364                                         cache->n_bytes = 0;
3365                                 }
3366
3367                                 yaffs_use_cache(dev, cache, 0);
3368
3369                                 cache->locked = 1;
3370
3371                                 memcpy(buffer, &cache->data[start], n_copy);
3372
3373                                 cache->locked = 0;
3374                         } else {
3375                                 /* Read into the local buffer then copy.. */
3376
3377                                 u8 *local_buffer =
3378                                     yaffs_get_temp_buffer(dev, __LINE__);
3379                                 yaffs_rd_data_obj(in, chunk, local_buffer);
3380
3381                                 memcpy(buffer, &local_buffer[start], n_copy);
3382
3383                                 yaffs_release_temp_buffer(dev, local_buffer,
3384                                                           __LINE__);
3385                         }
3386
3387                 } else {
3388
3389                         /* A full chunk. Read directly into the supplied buffer. */
3390                         yaffs_rd_data_obj(in, chunk, buffer);
3391
3392                 }
3393
3394                 n -= n_copy;
3395                 offset += n_copy;
3396                 buffer += n_copy;
3397                 n_done += n_copy;
3398
3399         }
3400
3401         return n_done;
3402 }
3403
3404 int yaffs_do_file_wr(struct yaffs_obj *in, const u8 * buffer, loff_t offset,
3405                      int n_bytes, int write_trhrough)
3406 {
3407
3408         int chunk;
3409         u32 start;
3410         int n_copy;
3411         int n = n_bytes;
3412         int n_done = 0;
3413         int n_writeback;
3414         int start_write = offset;
3415         int chunk_written = 0;
3416         u32 n_bytes_read;
3417         u32 chunk_start;
3418
3419         struct yaffs_dev *dev;
3420
3421         dev = in->my_dev;
3422
3423         while (n > 0 && chunk_written >= 0) {
3424                 yaffs_addr_to_chunk(dev, offset, &chunk, &start);
3425
3426                 if (chunk * dev->data_bytes_per_chunk + start != offset ||
3427                     start >= dev->data_bytes_per_chunk) {
3428                         T(YAFFS_TRACE_ERROR,
3429                           (TSTR
3430                            ("AddrToChunk of offset %d gives chunk %d start %d"
3431                             TENDSTR), (int)offset, chunk, start));
3432                 }
3433                 chunk++;        /* File pos to chunk in file offset */
3434
3435                 /* OK now check for the curveball where the start and end are in
3436                  * the same chunk.
3437                  */
3438
3439                 if ((start + n) < dev->data_bytes_per_chunk) {
3440                         n_copy = n;
3441
3442                         /* Now folks, to calculate how many bytes to write back....
3443                          * If we're overwriting and not writing to then end of file then
3444                          * we need to write back as much as was there before.
3445                          */
3446
3447                         chunk_start = ((chunk - 1) * dev->data_bytes_per_chunk);
3448
3449                         if (chunk_start > in->variant.file_variant.file_size)
3450                                 n_bytes_read = 0;       /* Past end of file */
3451                         else
3452                                 n_bytes_read =
3453                                     in->variant.file_variant.file_size -
3454                                     chunk_start;
3455
3456                         if (n_bytes_read > dev->data_bytes_per_chunk)
3457                                 n_bytes_read = dev->data_bytes_per_chunk;
3458
3459                         n_writeback =
3460                             (n_bytes_read >
3461                              (start + n)) ? n_bytes_read : (start + n);
3462
3463                         if (n_writeback < 0
3464                             || n_writeback > dev->data_bytes_per_chunk)
3465                                 YBUG();
3466
3467                 } else {
3468                         n_copy = dev->data_bytes_per_chunk - start;
3469                         n_writeback = dev->data_bytes_per_chunk;
3470                 }
3471
3472                 if (n_copy != dev->data_bytes_per_chunk
3473                     || dev->param.inband_tags) {
3474                         /* An incomplete start or end chunk (or maybe both start and end chunk),
3475                          * or we're using inband tags, so we want to use the cache buffers.
3476                          */
3477                         if (dev->param.n_caches > 0) {
3478                                 struct yaffs_cache *cache;
3479                                 /* If we can't find the data in the cache, then load the cache */
3480                                 cache = yaffs_find_chunk_cache(in, chunk);
3481
3482                                 if (!cache
3483                                     && yaffs_check_alloc_available(dev, 1)) {
3484                                         cache = yaffs_grab_chunk_cache(dev);
3485                                         cache->object = in;
3486                                         cache->chunk_id = chunk;
3487                                         cache->dirty = 0;
3488                                         cache->locked = 0;
3489                                         yaffs_rd_data_obj(in, chunk,
3490                                                           cache->data);
3491                                 } else if (cache &&
3492                                            !cache->dirty &&
3493                                            !yaffs_check_alloc_available(dev,
3494                                                                         1)) {
3495                                         /* Drop the cache if it was a read cache item and
3496                                          * no space check has been made for it.
3497                                          */
3498                                         cache = NULL;
3499                                 }
3500
3501                                 if (cache) {
3502                                         yaffs_use_cache(dev, cache, 1);
3503                                         cache->locked = 1;
3504
3505                                         memcpy(&cache->data[start], buffer,
3506                                                n_copy);
3507
3508                                         cache->locked = 0;
3509                                         cache->n_bytes = n_writeback;
3510
3511                                         if (write_trhrough) {
3512                                                 chunk_written =
3513                                                     yaffs_wr_data_obj
3514                                                     (cache->object,
3515                                                      cache->chunk_id,
3516                                                      cache->data,
3517                                                      cache->n_bytes, 1);
3518                                                 cache->dirty = 0;
3519                                         }
3520
3521                                 } else {
3522                                         chunk_written = -1;     /* fail the write */
3523                                 }
3524                         } else {
3525                                 /* An incomplete start or end chunk (or maybe both start and end chunk)
3526                                  * Read into the local buffer then copy, then copy over and write back.
3527                                  */
3528
3529                                 u8 *local_buffer =
3530                                     yaffs_get_temp_buffer(dev, __LINE__);
3531
3532                                 yaffs_rd_data_obj(in, chunk, local_buffer);
3533
3534                                 memcpy(&local_buffer[start], buffer, n_copy);
3535
3536                                 chunk_written =
3537                                     yaffs_wr_data_obj(in, chunk,
3538                                                       local_buffer,
3539                                                       n_writeback, 0);
3540
3541                                 yaffs_release_temp_buffer(dev, local_buffer,
3542                                                           __LINE__);
3543
3544                         }
3545
3546                 } else {
3547                         /* A full chunk. Write directly from the supplied buffer. */
3548
3549                         chunk_written =
3550                             yaffs_wr_data_obj(in, chunk, buffer,
3551                                               dev->data_bytes_per_chunk, 0);
3552
3553                         /* Since we've overwritten the cached data, we better invalidate it. */
3554                         yaffs_invalidate_chunk_cache(in, chunk);
3555                 }
3556
3557                 if (chunk_written >= 0) {
3558                         n -= n_copy;
3559                         offset += n_copy;
3560                         buffer += n_copy;
3561                         n_done += n_copy;
3562                 }
3563
3564         }
3565
3566         /* Update file object */
3567
3568         if ((start_write + n_done) > in->variant.file_variant.file_size)
3569                 in->variant.file_variant.file_size = (start_write + n_done);
3570
3571         in->dirty = 1;
3572
3573         return n_done;
3574 }
3575
3576 int yaffs_wr_file(struct yaffs_obj *in, const u8 * buffer, loff_t offset,
3577                   int n_bytes, int write_trhrough)
3578 {
3579         yaffs2_handle_hole(in, offset);
3580         return yaffs_do_file_wr(in, buffer, offset, n_bytes, write_trhrough);
3581 }
3582
3583 /* ---------------------- File resizing stuff ------------------ */
3584
3585 static void yaffs_prune_chunks(struct yaffs_obj *in, int new_size)
3586 {
3587
3588         struct yaffs_dev *dev = in->my_dev;
3589         int old_size = in->variant.file_variant.file_size;
3590
3591         int last_del = 1 + (old_size - 1) / dev->data_bytes_per_chunk;
3592
3593         int start_del = 1 + (new_size + dev->data_bytes_per_chunk - 1) /
3594             dev->data_bytes_per_chunk;
3595         int i;
3596         int chunk_id;
3597
3598         /* Delete backwards so that we don't end up with holes if
3599          * power is lost part-way through the operation.
3600          */
3601         for (i = last_del; i >= start_del; i--) {
3602                 /* NB this could be optimised somewhat,
3603                  * eg. could retrieve the tags and write them without
3604                  * using yaffs_chunk_del
3605                  */
3606
3607                 chunk_id = yaffs_find_del_file_chunk(in, i, NULL);
3608                 if (chunk_id > 0) {
3609                         if (chunk_id <
3610                             (dev->internal_start_block *
3611                              dev->param.chunks_per_block)
3612                             || chunk_id >=
3613                             ((dev->internal_end_block +
3614                               1) * dev->param.chunks_per_block)) {
3615                                 T(YAFFS_TRACE_ALWAYS,
3616                                   (TSTR
3617                                    ("Found daft chunk_id %d for %d" TENDSTR),
3618                                    chunk_id, i));
3619                         } else {
3620                                 in->n_data_chunks--;
3621                                 yaffs_chunk_del(dev, chunk_id, 1, __LINE__);
3622                         }
3623                 }
3624         }
3625
3626 }
3627
3628 void yaffs_resize_file_down(struct yaffs_obj *obj, loff_t new_size)
3629 {
3630         int new_full;
3631         u32 new_partial;
3632         struct yaffs_dev *dev = obj->my_dev;
3633
3634         yaffs_addr_to_chunk(dev, new_size, &new_full, &new_partial);
3635
3636         yaffs_prune_chunks(obj, new_size);
3637
3638         if (new_partial != 0) {
3639                 int last_chunk = 1 + new_full;
3640                 u8 *local_buffer = yaffs_get_temp_buffer(dev, __LINE__);
3641
3642                 /* Got to read and rewrite the last chunk with its new size and zero pad */
3643                 yaffs_rd_data_obj(obj, last_chunk, local_buffer);
3644                 memset(local_buffer + new_partial, 0,
3645                        dev->data_bytes_per_chunk - new_partial);
3646
3647                 yaffs_wr_data_obj(obj, last_chunk, local_buffer,
3648                                   new_partial, 1);
3649
3650                 yaffs_release_temp_buffer(dev, local_buffer, __LINE__);
3651         }
3652
3653         obj->variant.file_variant.file_size = new_size;
3654
3655         yaffs_prune_tree(dev, &obj->variant.file_variant);
3656 }
3657
3658 int yaffs_resize_file(struct yaffs_obj *in, loff_t new_size)
3659 {
3660         struct yaffs_dev *dev = in->my_dev;
3661         int old_size = in->variant.file_variant.file_size;
3662
3663         yaffs_flush_file_cache(in);
3664         yaffs_invalidate_whole_cache(in);
3665
3666         yaffs_check_gc(dev, 0);
3667
3668         if (in->variant_type != YAFFS_OBJECT_TYPE_FILE)
3669                 return YAFFS_FAIL;
3670
3671         if (new_size == old_size)
3672                 return YAFFS_OK;
3673
3674         if (new_size > old_size) {
3675                 yaffs2_handle_hole(in, new_size);
3676                 in->variant.file_variant.file_size = new_size;
3677         } else {
3678                 /* new_size < old_size */
3679                 yaffs_resize_file_down(in, new_size);
3680         }
3681
3682         /* Write a new object header to reflect the resize.
3683          * show we've shrunk the file, if need be
3684          * Do this only if the file is not in the deleted directories
3685          * and is not shadowed.
3686          */
3687         if (in->parent &&
3688             !in->is_shadowed &&
3689             in->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
3690             in->parent->obj_id != YAFFS_OBJECTID_DELETED)
3691                 yaffs_update_oh(in, NULL, 0, 0, 0, NULL);
3692
3693         return YAFFS_OK;
3694 }
3695
3696 int yaffs_flush_file(struct yaffs_obj *in, int update_time, int data_sync)
3697 {
3698         int ret_val;
3699         if (in->dirty) {
3700                 yaffs_flush_file_cache(in);
3701                 if (data_sync)  /* Only sync data */
3702                         ret_val = YAFFS_OK;
3703                 else {
3704                         if (update_time)
3705                                 yaffs_load_current_time(in, 0, 0);
3706
3707                         ret_val = (yaffs_update_oh(in, NULL, 0, 0, 0, NULL) >=
3708                                    0) ? YAFFS_OK : YAFFS_FAIL;
3709                 }
3710         } else {
3711                 ret_val = YAFFS_OK;
3712         }
3713
3714         return ret_val;
3715
3716 }
3717
3718 static int yaffs_generic_obj_del(struct yaffs_obj *in)
3719 {
3720
3721         /* First off, invalidate the file's data in the cache, without flushing. */
3722         yaffs_invalidate_whole_cache(in);
3723
3724         if (in->my_dev->param.is_yaffs2 && (in->parent != in->my_dev->del_dir)) {
3725                 /* Move to the unlinked directory so we have a record that it was deleted. */
3726                 yaffs_change_obj_name(in, in->my_dev->del_dir, _Y("deleted"), 0,
3727                                       0);
3728
3729         }
3730
3731         yaffs_remove_obj_from_dir(in);
3732         yaffs_chunk_del(in->my_dev, in->hdr_chunk, 1, __LINE__);
3733         in->hdr_chunk = 0;
3734
3735         yaffs_free_obj(in);
3736         return YAFFS_OK;
3737
3738 }
3739
3740 /* yaffs_del_file deletes the whole file data
3741  * and the inode associated with the file.
3742  * It does not delete the links associated with the file.
3743  */
3744 static int yaffs_unlink_file_if_needed(struct yaffs_obj *in)
3745 {
3746
3747         int ret_val;
3748         int del_now = 0;
3749         struct yaffs_dev *dev = in->my_dev;
3750
3751         if (!in->my_inode)
3752                 del_now = 1;
3753