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TOMOYO Linux Cross Reference
Linux/fs/ubifs/replay.c

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  1 /*
  2  * This file is part of UBIFS.
  3  *
  4  * Copyright (C) 2006-2008 Nokia Corporation.
  5  *
  6  * This program is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 as published by
  8  * the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 13  * more details.
 14  *
 15  * You should have received a copy of the GNU General Public License along with
 16  * this program; if not, write to the Free Software Foundation, Inc., 51
 17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 18  *
 19  * Authors: Adrian Hunter
 20  *          Artem Bityutskiy (Битюцкий Артём)
 21  */
 22 
 23 /*
 24  * This file contains journal replay code. It runs when the file-system is being
 25  * mounted and requires no locking.
 26  *
 27  * The larger is the journal, the longer it takes to scan it, so the longer it
 28  * takes to mount UBIFS. This is why the journal has limited size which may be
 29  * changed depending on the system requirements. But a larger journal gives
 30  * faster I/O speed because it writes the index less frequently. So this is a
 31  * trade-off. Also, the journal is indexed by the in-memory index (TNC), so the
 32  * larger is the journal, the more memory its index may consume.
 33  */
 34 
 35 #include "ubifs.h"
 36 #include <linux/list_sort.h>
 37 
 38 /**
 39  * struct replay_entry - replay list entry.
 40  * @lnum: logical eraseblock number of the node
 41  * @offs: node offset
 42  * @len: node length
 43  * @deletion: non-zero if this entry corresponds to a node deletion
 44  * @sqnum: node sequence number
 45  * @list: links the replay list
 46  * @key: node key
 47  * @nm: directory entry name
 48  * @old_size: truncation old size
 49  * @new_size: truncation new size
 50  *
 51  * The replay process first scans all buds and builds the replay list, then
 52  * sorts the replay list in nodes sequence number order, and then inserts all
 53  * the replay entries to the TNC.
 54  */
 55 struct replay_entry {
 56         int lnum;
 57         int offs;
 58         int len;
 59         unsigned int deletion:1;
 60         unsigned long long sqnum;
 61         struct list_head list;
 62         union ubifs_key key;
 63         union {
 64                 struct fscrypt_name nm;
 65                 struct {
 66                         loff_t old_size;
 67                         loff_t new_size;
 68                 };
 69         };
 70 };
 71 
 72 /**
 73  * struct bud_entry - entry in the list of buds to replay.
 74  * @list: next bud in the list
 75  * @bud: bud description object
 76  * @sqnum: reference node sequence number
 77  * @free: free bytes in the bud
 78  * @dirty: dirty bytes in the bud
 79  */
 80 struct bud_entry {
 81         struct list_head list;
 82         struct ubifs_bud *bud;
 83         unsigned long long sqnum;
 84         int free;
 85         int dirty;
 86 };
 87 
 88 /**
 89  * set_bud_lprops - set free and dirty space used by a bud.
 90  * @c: UBIFS file-system description object
 91  * @b: bud entry which describes the bud
 92  *
 93  * This function makes sure the LEB properties of bud @b are set correctly
 94  * after the replay. Returns zero in case of success and a negative error code
 95  * in case of failure.
 96  */
 97 static int set_bud_lprops(struct ubifs_info *c, struct bud_entry *b)
 98 {
 99         const struct ubifs_lprops *lp;
100         int err = 0, dirty;
101 
102         ubifs_get_lprops(c);
103 
104         lp = ubifs_lpt_lookup_dirty(c, b->bud->lnum);
105         if (IS_ERR(lp)) {
106                 err = PTR_ERR(lp);
107                 goto out;
108         }
109 
110         dirty = lp->dirty;
111         if (b->bud->start == 0 && (lp->free != c->leb_size || lp->dirty != 0)) {
112                 /*
113                  * The LEB was added to the journal with a starting offset of
114                  * zero which means the LEB must have been empty. The LEB
115                  * property values should be @lp->free == @c->leb_size and
116                  * @lp->dirty == 0, but that is not the case. The reason is that
117                  * the LEB had been garbage collected before it became the bud,
118                  * and there was not commit inbetween. The garbage collector
119                  * resets the free and dirty space without recording it
120                  * anywhere except lprops, so if there was no commit then
121                  * lprops does not have that information.
122                  *
123                  * We do not need to adjust free space because the scan has told
124                  * us the exact value which is recorded in the replay entry as
125                  * @b->free.
126                  *
127                  * However we do need to subtract from the dirty space the
128                  * amount of space that the garbage collector reclaimed, which
129                  * is the whole LEB minus the amount of space that was free.
130                  */
131                 dbg_mnt("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
132                         lp->free, lp->dirty);
133                 dbg_gc("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
134                         lp->free, lp->dirty);
135                 dirty -= c->leb_size - lp->free;
136                 /*
137                  * If the replay order was perfect the dirty space would now be
138                  * zero. The order is not perfect because the journal heads
139                  * race with each other. This is not a problem but is does mean
140                  * that the dirty space may temporarily exceed c->leb_size
141                  * during the replay.
142                  */
143                 if (dirty != 0)
144                         dbg_mnt("LEB %d lp: %d free %d dirty replay: %d free %d dirty",
145                                 b->bud->lnum, lp->free, lp->dirty, b->free,
146                                 b->dirty);
147         }
148         lp = ubifs_change_lp(c, lp, b->free, dirty + b->dirty,
149                              lp->flags | LPROPS_TAKEN, 0);
150         if (IS_ERR(lp)) {
151                 err = PTR_ERR(lp);
152                 goto out;
153         }
154 
155         /* Make sure the journal head points to the latest bud */
156         err = ubifs_wbuf_seek_nolock(&c->jheads[b->bud->jhead].wbuf,
157                                      b->bud->lnum, c->leb_size - b->free);
158 
159 out:
160         ubifs_release_lprops(c);
161         return err;
162 }
163 
164 /**
165  * set_buds_lprops - set free and dirty space for all replayed buds.
166  * @c: UBIFS file-system description object
167  *
168  * This function sets LEB properties for all replayed buds. Returns zero in
169  * case of success and a negative error code in case of failure.
170  */
171 static int set_buds_lprops(struct ubifs_info *c)
172 {
173         struct bud_entry *b;
174         int err;
175 
176         list_for_each_entry(b, &c->replay_buds, list) {
177                 err = set_bud_lprops(c, b);
178                 if (err)
179                         return err;
180         }
181 
182         return 0;
183 }
184 
185 /**
186  * trun_remove_range - apply a replay entry for a truncation to the TNC.
187  * @c: UBIFS file-system description object
188  * @r: replay entry of truncation
189  */
190 static int trun_remove_range(struct ubifs_info *c, struct replay_entry *r)
191 {
192         unsigned min_blk, max_blk;
193         union ubifs_key min_key, max_key;
194         ino_t ino;
195 
196         min_blk = r->new_size / UBIFS_BLOCK_SIZE;
197         if (r->new_size & (UBIFS_BLOCK_SIZE - 1))
198                 min_blk += 1;
199 
200         max_blk = r->old_size / UBIFS_BLOCK_SIZE;
201         if ((r->old_size & (UBIFS_BLOCK_SIZE - 1)) == 0)
202                 max_blk -= 1;
203 
204         ino = key_inum(c, &r->key);
205 
206         data_key_init(c, &min_key, ino, min_blk);
207         data_key_init(c, &max_key, ino, max_blk);
208 
209         return ubifs_tnc_remove_range(c, &min_key, &max_key);
210 }
211 
212 /**
213  * apply_replay_entry - apply a replay entry to the TNC.
214  * @c: UBIFS file-system description object
215  * @r: replay entry to apply
216  *
217  * Apply a replay entry to the TNC.
218  */
219 static int apply_replay_entry(struct ubifs_info *c, struct replay_entry *r)
220 {
221         int err;
222 
223         dbg_mntk(&r->key, "LEB %d:%d len %d deletion %d sqnum %llu key ",
224                  r->lnum, r->offs, r->len, r->deletion, r->sqnum);
225 
226         /* Set c->replay_sqnum to help deal with dangling branches. */
227         c->replay_sqnum = r->sqnum;
228 
229         if (is_hash_key(c, &r->key)) {
230                 if (r->deletion)
231                         err = ubifs_tnc_remove_nm(c, &r->key, &r->nm);
232                 else
233                         err = ubifs_tnc_add_nm(c, &r->key, r->lnum, r->offs,
234                                                r->len, &r->nm);
235         } else {
236                 if (r->deletion)
237                         switch (key_type(c, &r->key)) {
238                         case UBIFS_INO_KEY:
239                         {
240                                 ino_t inum = key_inum(c, &r->key);
241 
242                                 err = ubifs_tnc_remove_ino(c, inum);
243                                 break;
244                         }
245                         case UBIFS_TRUN_KEY:
246                                 err = trun_remove_range(c, r);
247                                 break;
248                         default:
249                                 err = ubifs_tnc_remove(c, &r->key);
250                                 break;
251                         }
252                 else
253                         err = ubifs_tnc_add(c, &r->key, r->lnum, r->offs,
254                                             r->len);
255                 if (err)
256                         return err;
257 
258                 if (c->need_recovery)
259                         err = ubifs_recover_size_accum(c, &r->key, r->deletion,
260                                                        r->new_size);
261         }
262 
263         return err;
264 }
265 
266 /**
267  * replay_entries_cmp - compare 2 replay entries.
268  * @priv: UBIFS file-system description object
269  * @a: first replay entry
270  * @b: second replay entry
271  *
272  * This is a comparios function for 'list_sort()' which compares 2 replay
273  * entries @a and @b by comparing their sequence numer.  Returns %1 if @a has
274  * greater sequence number and %-1 otherwise.
275  */
276 static int replay_entries_cmp(void *priv, struct list_head *a,
277                               struct list_head *b)
278 {
279         struct replay_entry *ra, *rb;
280 
281         cond_resched();
282         if (a == b)
283                 return 0;
284 
285         ra = list_entry(a, struct replay_entry, list);
286         rb = list_entry(b, struct replay_entry, list);
287         ubifs_assert(ra->sqnum != rb->sqnum);
288         if (ra->sqnum > rb->sqnum)
289                 return 1;
290         return -1;
291 }
292 
293 /**
294  * apply_replay_list - apply the replay list to the TNC.
295  * @c: UBIFS file-system description object
296  *
297  * Apply all entries in the replay list to the TNC. Returns zero in case of
298  * success and a negative error code in case of failure.
299  */
300 static int apply_replay_list(struct ubifs_info *c)
301 {
302         struct replay_entry *r;
303         int err;
304 
305         list_sort(c, &c->replay_list, &replay_entries_cmp);
306 
307         list_for_each_entry(r, &c->replay_list, list) {
308                 cond_resched();
309 
310                 err = apply_replay_entry(c, r);
311                 if (err)
312                         return err;
313         }
314 
315         return 0;
316 }
317 
318 /**
319  * destroy_replay_list - destroy the replay.
320  * @c: UBIFS file-system description object
321  *
322  * Destroy the replay list.
323  */
324 static void destroy_replay_list(struct ubifs_info *c)
325 {
326         struct replay_entry *r, *tmp;
327 
328         list_for_each_entry_safe(r, tmp, &c->replay_list, list) {
329                 if (is_hash_key(c, &r->key))
330                         kfree(fname_name(&r->nm));
331                 list_del(&r->list);
332                 kfree(r);
333         }
334 }
335 
336 /**
337  * insert_node - insert a node to the replay list
338  * @c: UBIFS file-system description object
339  * @lnum: node logical eraseblock number
340  * @offs: node offset
341  * @len: node length
342  * @key: node key
343  * @sqnum: sequence number
344  * @deletion: non-zero if this is a deletion
345  * @used: number of bytes in use in a LEB
346  * @old_size: truncation old size
347  * @new_size: truncation new size
348  *
349  * This function inserts a scanned non-direntry node to the replay list. The
350  * replay list contains @struct replay_entry elements, and we sort this list in
351  * sequence number order before applying it. The replay list is applied at the
352  * very end of the replay process. Since the list is sorted in sequence number
353  * order, the older modifications are applied first. This function returns zero
354  * in case of success and a negative error code in case of failure.
355  */
356 static int insert_node(struct ubifs_info *c, int lnum, int offs, int len,
357                        union ubifs_key *key, unsigned long long sqnum,
358                        int deletion, int *used, loff_t old_size,
359                        loff_t new_size)
360 {
361         struct replay_entry *r;
362 
363         dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
364 
365         if (key_inum(c, key) >= c->highest_inum)
366                 c->highest_inum = key_inum(c, key);
367 
368         r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
369         if (!r)
370                 return -ENOMEM;
371 
372         if (!deletion)
373                 *used += ALIGN(len, 8);
374         r->lnum = lnum;
375         r->offs = offs;
376         r->len = len;
377         r->deletion = !!deletion;
378         r->sqnum = sqnum;
379         key_copy(c, key, &r->key);
380         r->old_size = old_size;
381         r->new_size = new_size;
382 
383         list_add_tail(&r->list, &c->replay_list);
384         return 0;
385 }
386 
387 /**
388  * insert_dent - insert a directory entry node into the replay list.
389  * @c: UBIFS file-system description object
390  * @lnum: node logical eraseblock number
391  * @offs: node offset
392  * @len: node length
393  * @key: node key
394  * @name: directory entry name
395  * @nlen: directory entry name length
396  * @sqnum: sequence number
397  * @deletion: non-zero if this is a deletion
398  * @used: number of bytes in use in a LEB
399  *
400  * This function inserts a scanned directory entry node or an extended
401  * attribute entry to the replay list. Returns zero in case of success and a
402  * negative error code in case of failure.
403  */
404 static int insert_dent(struct ubifs_info *c, int lnum, int offs, int len,
405                        union ubifs_key *key, const char *name, int nlen,
406                        unsigned long long sqnum, int deletion, int *used)
407 {
408         struct replay_entry *r;
409         char *nbuf;
410 
411         dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
412         if (key_inum(c, key) >= c->highest_inum)
413                 c->highest_inum = key_inum(c, key);
414 
415         r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
416         if (!r)
417                 return -ENOMEM;
418 
419         nbuf = kmalloc(nlen + 1, GFP_KERNEL);
420         if (!nbuf) {
421                 kfree(r);
422                 return -ENOMEM;
423         }
424 
425         if (!deletion)
426                 *used += ALIGN(len, 8);
427         r->lnum = lnum;
428         r->offs = offs;
429         r->len = len;
430         r->deletion = !!deletion;
431         r->sqnum = sqnum;
432         key_copy(c, key, &r->key);
433         fname_len(&r->nm) = nlen;
434         memcpy(nbuf, name, nlen);
435         nbuf[nlen] = '\0';
436         fname_name(&r->nm) = nbuf;
437 
438         list_add_tail(&r->list, &c->replay_list);
439         return 0;
440 }
441 
442 /**
443  * ubifs_validate_entry - validate directory or extended attribute entry node.
444  * @c: UBIFS file-system description object
445  * @dent: the node to validate
446  *
447  * This function validates directory or extended attribute entry node @dent.
448  * Returns zero if the node is all right and a %-EINVAL if not.
449  */
450 int ubifs_validate_entry(struct ubifs_info *c,
451                          const struct ubifs_dent_node *dent)
452 {
453         int key_type = key_type_flash(c, dent->key);
454         int nlen = le16_to_cpu(dent->nlen);
455 
456         if (le32_to_cpu(dent->ch.len) != nlen + UBIFS_DENT_NODE_SZ + 1 ||
457             dent->type >= UBIFS_ITYPES_CNT ||
458             nlen > UBIFS_MAX_NLEN || dent->name[nlen] != 0 ||
459             (key_type == UBIFS_XENT_KEY && strnlen(dent->name, nlen) != nlen) ||
460             le64_to_cpu(dent->inum) > MAX_INUM) {
461                 ubifs_err(c, "bad %s node", key_type == UBIFS_DENT_KEY ?
462                           "directory entry" : "extended attribute entry");
463                 return -EINVAL;
464         }
465 
466         if (key_type != UBIFS_DENT_KEY && key_type != UBIFS_XENT_KEY) {
467                 ubifs_err(c, "bad key type %d", key_type);
468                 return -EINVAL;
469         }
470 
471         return 0;
472 }
473 
474 /**
475  * is_last_bud - check if the bud is the last in the journal head.
476  * @c: UBIFS file-system description object
477  * @bud: bud description object
478  *
479  * This function checks if bud @bud is the last bud in its journal head. This
480  * information is then used by 'replay_bud()' to decide whether the bud can
481  * have corruptions or not. Indeed, only last buds can be corrupted by power
482  * cuts. Returns %1 if this is the last bud, and %0 if not.
483  */
484 static int is_last_bud(struct ubifs_info *c, struct ubifs_bud *bud)
485 {
486         struct ubifs_jhead *jh = &c->jheads[bud->jhead];
487         struct ubifs_bud *next;
488         uint32_t data;
489         int err;
490 
491         if (list_is_last(&bud->list, &jh->buds_list))
492                 return 1;
493 
494         /*
495          * The following is a quirk to make sure we work correctly with UBIFS
496          * images used with older UBIFS.
497          *
498          * Normally, the last bud will be the last in the journal head's list
499          * of bud. However, there is one exception if the UBIFS image belongs
500          * to older UBIFS. This is fairly unlikely: one would need to use old
501          * UBIFS, then have a power cut exactly at the right point, and then
502          * try to mount this image with new UBIFS.
503          *
504          * The exception is: it is possible to have 2 buds A and B, A goes
505          * before B, and B is the last, bud B is contains no data, and bud A is
506          * corrupted at the end. The reason is that in older versions when the
507          * journal code switched the next bud (from A to B), it first added a
508          * log reference node for the new bud (B), and only after this it
509          * synchronized the write-buffer of current bud (A). But later this was
510          * changed and UBIFS started to always synchronize the write-buffer of
511          * the bud (A) before writing the log reference for the new bud (B).
512          *
513          * But because older UBIFS always synchronized A's write-buffer before
514          * writing to B, we can recognize this exceptional situation but
515          * checking the contents of bud B - if it is empty, then A can be
516          * treated as the last and we can recover it.
517          *
518          * TODO: remove this piece of code in a couple of years (today it is
519          * 16.05.2011).
520          */
521         next = list_entry(bud->list.next, struct ubifs_bud, list);
522         if (!list_is_last(&next->list, &jh->buds_list))
523                 return 0;
524 
525         err = ubifs_leb_read(c, next->lnum, (char *)&data, next->start, 4, 1);
526         if (err)
527                 return 0;
528 
529         return data == 0xFFFFFFFF;
530 }
531 
532 /**
533  * replay_bud - replay a bud logical eraseblock.
534  * @c: UBIFS file-system description object
535  * @b: bud entry which describes the bud
536  *
537  * This function replays bud @bud, recovers it if needed, and adds all nodes
538  * from this bud to the replay list. Returns zero in case of success and a
539  * negative error code in case of failure.
540  */
541 static int replay_bud(struct ubifs_info *c, struct bud_entry *b)
542 {
543         int is_last = is_last_bud(c, b->bud);
544         int err = 0, used = 0, lnum = b->bud->lnum, offs = b->bud->start;
545         struct ubifs_scan_leb *sleb;
546         struct ubifs_scan_node *snod;
547 
548         dbg_mnt("replay bud LEB %d, head %d, offs %d, is_last %d",
549                 lnum, b->bud->jhead, offs, is_last);
550 
551         if (c->need_recovery && is_last)
552                 /*
553                  * Recover only last LEBs in the journal heads, because power
554                  * cuts may cause corruptions only in these LEBs, because only
555                  * these LEBs could possibly be written to at the power cut
556                  * time.
557                  */
558                 sleb = ubifs_recover_leb(c, lnum, offs, c->sbuf, b->bud->jhead);
559         else
560                 sleb = ubifs_scan(c, lnum, offs, c->sbuf, 0);
561         if (IS_ERR(sleb))
562                 return PTR_ERR(sleb);
563 
564         /*
565          * The bud does not have to start from offset zero - the beginning of
566          * the 'lnum' LEB may contain previously committed data. One of the
567          * things we have to do in replay is to correctly update lprops with
568          * newer information about this LEB.
569          *
570          * At this point lprops thinks that this LEB has 'c->leb_size - offs'
571          * bytes of free space because it only contain information about
572          * committed data.
573          *
574          * But we know that real amount of free space is 'c->leb_size -
575          * sleb->endpt', and the space in the 'lnum' LEB between 'offs' and
576          * 'sleb->endpt' is used by bud data. We have to correctly calculate
577          * how much of these data are dirty and update lprops with this
578          * information.
579          *
580          * The dirt in that LEB region is comprised of padding nodes, deletion
581          * nodes, truncation nodes and nodes which are obsoleted by subsequent
582          * nodes in this LEB. So instead of calculating clean space, we
583          * calculate used space ('used' variable).
584          */
585 
586         list_for_each_entry(snod, &sleb->nodes, list) {
587                 int deletion = 0;
588 
589                 cond_resched();
590 
591                 if (snod->sqnum >= SQNUM_WATERMARK) {
592                         ubifs_err(c, "file system's life ended");
593                         goto out_dump;
594                 }
595 
596                 if (snod->sqnum > c->max_sqnum)
597                         c->max_sqnum = snod->sqnum;
598 
599                 switch (snod->type) {
600                 case UBIFS_INO_NODE:
601                 {
602                         struct ubifs_ino_node *ino = snod->node;
603                         loff_t new_size = le64_to_cpu(ino->size);
604 
605                         if (le32_to_cpu(ino->nlink) == 0)
606                                 deletion = 1;
607                         err = insert_node(c, lnum, snod->offs, snod->len,
608                                           &snod->key, snod->sqnum, deletion,
609                                           &used, 0, new_size);
610                         break;
611                 }
612                 case UBIFS_DATA_NODE:
613                 {
614                         struct ubifs_data_node *dn = snod->node;
615                         loff_t new_size = le32_to_cpu(dn->size) +
616                                           key_block(c, &snod->key) *
617                                           UBIFS_BLOCK_SIZE;
618 
619                         err = insert_node(c, lnum, snod->offs, snod->len,
620                                           &snod->key, snod->sqnum, deletion,
621                                           &used, 0, new_size);
622                         break;
623                 }
624                 case UBIFS_DENT_NODE:
625                 case UBIFS_XENT_NODE:
626                 {
627                         struct ubifs_dent_node *dent = snod->node;
628 
629                         err = ubifs_validate_entry(c, dent);
630                         if (err)
631                                 goto out_dump;
632 
633                         err = insert_dent(c, lnum, snod->offs, snod->len,
634                                           &snod->key, dent->name,
635                                           le16_to_cpu(dent->nlen), snod->sqnum,
636                                           !le64_to_cpu(dent->inum), &used);
637                         break;
638                 }
639                 case UBIFS_TRUN_NODE:
640                 {
641                         struct ubifs_trun_node *trun = snod->node;
642                         loff_t old_size = le64_to_cpu(trun->old_size);
643                         loff_t new_size = le64_to_cpu(trun->new_size);
644                         union ubifs_key key;
645 
646                         /* Validate truncation node */
647                         if (old_size < 0 || old_size > c->max_inode_sz ||
648                             new_size < 0 || new_size > c->max_inode_sz ||
649                             old_size <= new_size) {
650                                 ubifs_err(c, "bad truncation node");
651                                 goto out_dump;
652                         }
653 
654                         /*
655                          * Create a fake truncation key just to use the same
656                          * functions which expect nodes to have keys.
657                          */
658                         trun_key_init(c, &key, le32_to_cpu(trun->inum));
659                         err = insert_node(c, lnum, snod->offs, snod->len,
660                                           &key, snod->sqnum, 1, &used,
661                                           old_size, new_size);
662                         break;
663                 }
664                 default:
665                         ubifs_err(c, "unexpected node type %d in bud LEB %d:%d",
666                                   snod->type, lnum, snod->offs);
667                         err = -EINVAL;
668                         goto out_dump;
669                 }
670                 if (err)
671                         goto out;
672         }
673 
674         ubifs_assert(ubifs_search_bud(c, lnum));
675         ubifs_assert(sleb->endpt - offs >= used);
676         ubifs_assert(sleb->endpt % c->min_io_size == 0);
677 
678         b->dirty = sleb->endpt - offs - used;
679         b->free = c->leb_size - sleb->endpt;
680         dbg_mnt("bud LEB %d replied: dirty %d, free %d",
681                 lnum, b->dirty, b->free);
682 
683 out:
684         ubifs_scan_destroy(sleb);
685         return err;
686 
687 out_dump:
688         ubifs_err(c, "bad node is at LEB %d:%d", lnum, snod->offs);
689         ubifs_dump_node(c, snod->node);
690         ubifs_scan_destroy(sleb);
691         return -EINVAL;
692 }
693 
694 /**
695  * replay_buds - replay all buds.
696  * @c: UBIFS file-system description object
697  *
698  * This function returns zero in case of success and a negative error code in
699  * case of failure.
700  */
701 static int replay_buds(struct ubifs_info *c)
702 {
703         struct bud_entry *b;
704         int err;
705         unsigned long long prev_sqnum = 0;
706 
707         list_for_each_entry(b, &c->replay_buds, list) {
708                 err = replay_bud(c, b);
709                 if (err)
710                         return err;
711 
712                 ubifs_assert(b->sqnum > prev_sqnum);
713                 prev_sqnum = b->sqnum;
714         }
715 
716         return 0;
717 }
718 
719 /**
720  * destroy_bud_list - destroy the list of buds to replay.
721  * @c: UBIFS file-system description object
722  */
723 static void destroy_bud_list(struct ubifs_info *c)
724 {
725         struct bud_entry *b;
726 
727         while (!list_empty(&c->replay_buds)) {
728                 b = list_entry(c->replay_buds.next, struct bud_entry, list);
729                 list_del(&b->list);
730                 kfree(b);
731         }
732 }
733 
734 /**
735  * add_replay_bud - add a bud to the list of buds to replay.
736  * @c: UBIFS file-system description object
737  * @lnum: bud logical eraseblock number to replay
738  * @offs: bud start offset
739  * @jhead: journal head to which this bud belongs
740  * @sqnum: reference node sequence number
741  *
742  * This function returns zero in case of success and a negative error code in
743  * case of failure.
744  */
745 static int add_replay_bud(struct ubifs_info *c, int lnum, int offs, int jhead,
746                           unsigned long long sqnum)
747 {
748         struct ubifs_bud *bud;
749         struct bud_entry *b;
750 
751         dbg_mnt("add replay bud LEB %d:%d, head %d", lnum, offs, jhead);
752 
753         bud = kmalloc(sizeof(struct ubifs_bud), GFP_KERNEL);
754         if (!bud)
755                 return -ENOMEM;
756 
757         b = kmalloc(sizeof(struct bud_entry), GFP_KERNEL);
758         if (!b) {
759                 kfree(bud);
760                 return -ENOMEM;
761         }
762 
763         bud->lnum = lnum;
764         bud->start = offs;
765         bud->jhead = jhead;
766         ubifs_add_bud(c, bud);
767 
768         b->bud = bud;
769         b->sqnum = sqnum;
770         list_add_tail(&b->list, &c->replay_buds);
771 
772         return 0;
773 }
774 
775 /**
776  * validate_ref - validate a reference node.
777  * @c: UBIFS file-system description object
778  * @ref: the reference node to validate
779  * @ref_lnum: LEB number of the reference node
780  * @ref_offs: reference node offset
781  *
782  * This function returns %1 if a bud reference already exists for the LEB. %0 is
783  * returned if the reference node is new, otherwise %-EINVAL is returned if
784  * validation failed.
785  */
786 static int validate_ref(struct ubifs_info *c, const struct ubifs_ref_node *ref)
787 {
788         struct ubifs_bud *bud;
789         int lnum = le32_to_cpu(ref->lnum);
790         unsigned int offs = le32_to_cpu(ref->offs);
791         unsigned int jhead = le32_to_cpu(ref->jhead);
792 
793         /*
794          * ref->offs may point to the end of LEB when the journal head points
795          * to the end of LEB and we write reference node for it during commit.
796          * So this is why we require 'offs > c->leb_size'.
797          */
798         if (jhead >= c->jhead_cnt || lnum >= c->leb_cnt ||
799             lnum < c->main_first || offs > c->leb_size ||
800             offs & (c->min_io_size - 1))
801                 return -EINVAL;
802 
803         /* Make sure we have not already looked at this bud */
804         bud = ubifs_search_bud(c, lnum);
805         if (bud) {
806                 if (bud->jhead == jhead && bud->start <= offs)
807                         return 1;
808                 ubifs_err(c, "bud at LEB %d:%d was already referred", lnum, offs);
809                 return -EINVAL;
810         }
811 
812         return 0;
813 }
814 
815 /**
816  * replay_log_leb - replay a log logical eraseblock.
817  * @c: UBIFS file-system description object
818  * @lnum: log logical eraseblock to replay
819  * @offs: offset to start replaying from
820  * @sbuf: scan buffer
821  *
822  * This function replays a log LEB and returns zero in case of success, %1 if
823  * this is the last LEB in the log, and a negative error code in case of
824  * failure.
825  */
826 static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf)
827 {
828         int err;
829         struct ubifs_scan_leb *sleb;
830         struct ubifs_scan_node *snod;
831         const struct ubifs_cs_node *node;
832 
833         dbg_mnt("replay log LEB %d:%d", lnum, offs);
834         sleb = ubifs_scan(c, lnum, offs, sbuf, c->need_recovery);
835         if (IS_ERR(sleb)) {
836                 if (PTR_ERR(sleb) != -EUCLEAN || !c->need_recovery)
837                         return PTR_ERR(sleb);
838                 /*
839                  * Note, the below function will recover this log LEB only if
840                  * it is the last, because unclean reboots can possibly corrupt
841                  * only the tail of the log.
842                  */
843                 sleb = ubifs_recover_log_leb(c, lnum, offs, sbuf);
844                 if (IS_ERR(sleb))
845                         return PTR_ERR(sleb);
846         }
847 
848         if (sleb->nodes_cnt == 0) {
849                 err = 1;
850                 goto out;
851         }
852 
853         node = sleb->buf;
854         snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
855         if (c->cs_sqnum == 0) {
856                 /*
857                  * This is the first log LEB we are looking at, make sure that
858                  * the first node is a commit start node. Also record its
859                  * sequence number so that UBIFS can determine where the log
860                  * ends, because all nodes which were have higher sequence
861                  * numbers.
862                  */
863                 if (snod->type != UBIFS_CS_NODE) {
864                         ubifs_err(c, "first log node at LEB %d:%d is not CS node",
865                                   lnum, offs);
866                         goto out_dump;
867                 }
868                 if (le64_to_cpu(node->cmt_no) != c->cmt_no) {
869                         ubifs_err(c, "first CS node at LEB %d:%d has wrong commit number %llu expected %llu",
870                                   lnum, offs,
871                                   (unsigned long long)le64_to_cpu(node->cmt_no),
872                                   c->cmt_no);
873                         goto out_dump;
874                 }
875 
876                 c->cs_sqnum = le64_to_cpu(node->ch.sqnum);
877                 dbg_mnt("commit start sqnum %llu", c->cs_sqnum);
878         }
879 
880         if (snod->sqnum < c->cs_sqnum) {
881                 /*
882                  * This means that we reached end of log and now
883                  * look to the older log data, which was already
884                  * committed but the eraseblock was not erased (UBIFS
885                  * only un-maps it). So this basically means we have to
886                  * exit with "end of log" code.
887                  */
888                 err = 1;
889                 goto out;
890         }
891 
892         /* Make sure the first node sits at offset zero of the LEB */
893         if (snod->offs != 0) {
894                 ubifs_err(c, "first node is not at zero offset");
895                 goto out_dump;
896         }
897 
898         list_for_each_entry(snod, &sleb->nodes, list) {
899                 cond_resched();
900 
901                 if (snod->sqnum >= SQNUM_WATERMARK) {
902                         ubifs_err(c, "file system's life ended");
903                         goto out_dump;
904                 }
905 
906                 if (snod->sqnum < c->cs_sqnum) {
907                         ubifs_err(c, "bad sqnum %llu, commit sqnum %llu",
908                                   snod->sqnum, c->cs_sqnum);
909                         goto out_dump;
910                 }
911 
912                 if (snod->sqnum > c->max_sqnum)
913                         c->max_sqnum = snod->sqnum;
914 
915                 switch (snod->type) {
916                 case UBIFS_REF_NODE: {
917                         const struct ubifs_ref_node *ref = snod->node;
918 
919                         err = validate_ref(c, ref);
920                         if (err == 1)
921                                 break; /* Already have this bud */
922                         if (err)
923                                 goto out_dump;
924 
925                         err = add_replay_bud(c, le32_to_cpu(ref->lnum),
926                                              le32_to_cpu(ref->offs),
927                                              le32_to_cpu(ref->jhead),
928                                              snod->sqnum);
929                         if (err)
930                                 goto out;
931 
932                         break;
933                 }
934                 case UBIFS_CS_NODE:
935                         /* Make sure it sits at the beginning of LEB */
936                         if (snod->offs != 0) {
937                                 ubifs_err(c, "unexpected node in log");
938                                 goto out_dump;
939                         }
940                         break;
941                 default:
942                         ubifs_err(c, "unexpected node in log");
943                         goto out_dump;
944                 }
945         }
946 
947         if (sleb->endpt || c->lhead_offs >= c->leb_size) {
948                 c->lhead_lnum = lnum;
949                 c->lhead_offs = sleb->endpt;
950         }
951 
952         err = !sleb->endpt;
953 out:
954         ubifs_scan_destroy(sleb);
955         return err;
956 
957 out_dump:
958         ubifs_err(c, "log error detected while replaying the log at LEB %d:%d",
959                   lnum, offs + snod->offs);
960         ubifs_dump_node(c, snod->node);
961         ubifs_scan_destroy(sleb);
962         return -EINVAL;
963 }
964 
965 /**
966  * take_ihead - update the status of the index head in lprops to 'taken'.
967  * @c: UBIFS file-system description object
968  *
969  * This function returns the amount of free space in the index head LEB or a
970  * negative error code.
971  */
972 static int take_ihead(struct ubifs_info *c)
973 {
974         const struct ubifs_lprops *lp;
975         int err, free;
976 
977         ubifs_get_lprops(c);
978 
979         lp = ubifs_lpt_lookup_dirty(c, c->ihead_lnum);
980         if (IS_ERR(lp)) {
981                 err = PTR_ERR(lp);
982                 goto out;
983         }
984 
985         free = lp->free;
986 
987         lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
988                              lp->flags | LPROPS_TAKEN, 0);
989         if (IS_ERR(lp)) {
990                 err = PTR_ERR(lp);
991                 goto out;
992         }
993 
994         err = free;
995 out:
996         ubifs_release_lprops(c);
997         return err;
998 }
999 
1000 /**
1001  * ubifs_replay_journal - replay journal.
1002  * @c: UBIFS file-system description object
1003  *
1004  * This function scans the journal, replays and cleans it up. It makes sure all
1005  * memory data structures related to uncommitted journal are built (dirty TNC
1006  * tree, tree of buds, modified lprops, etc).
1007  */
1008 int ubifs_replay_journal(struct ubifs_info *c)
1009 {
1010         int err, lnum, free;
1011 
1012         BUILD_BUG_ON(UBIFS_TRUN_KEY > 5);
1013 
1014         /* Update the status of the index head in lprops to 'taken' */
1015         free = take_ihead(c);
1016         if (free < 0)
1017                 return free; /* Error code */
1018 
1019         if (c->ihead_offs != c->leb_size - free) {
1020                 ubifs_err(c, "bad index head LEB %d:%d", c->ihead_lnum,
1021                           c->ihead_offs);
1022                 return -EINVAL;
1023         }
1024 
1025         dbg_mnt("start replaying the journal");
1026         c->replaying = 1;
1027         lnum = c->ltail_lnum = c->lhead_lnum;
1028 
1029         do {
1030                 err = replay_log_leb(c, lnum, 0, c->sbuf);
1031                 if (err == 1) {
1032                         if (lnum != c->lhead_lnum)
1033                                 /* We hit the end of the log */
1034                                 break;
1035 
1036                         /*
1037                          * The head of the log must always start with the
1038                          * "commit start" node on a properly formatted UBIFS.
1039                          * But we found no nodes at all, which means that
1040                          * someting went wrong and we cannot proceed mounting
1041                          * the file-system.
1042                          */
1043                         ubifs_err(c, "no UBIFS nodes found at the log head LEB %d:%d, possibly corrupted",
1044                                   lnum, 0);
1045                         err = -EINVAL;
1046                 }
1047                 if (err)
1048                         goto out;
1049                 lnum = ubifs_next_log_lnum(c, lnum);
1050         } while (lnum != c->ltail_lnum);
1051 
1052         err = replay_buds(c);
1053         if (err)
1054                 goto out;
1055 
1056         err = apply_replay_list(c);
1057         if (err)
1058                 goto out;
1059 
1060         err = set_buds_lprops(c);
1061         if (err)
1062                 goto out;
1063 
1064         /*
1065          * UBIFS budgeting calculations use @c->bi.uncommitted_idx variable
1066          * to roughly estimate index growth. Things like @c->bi.min_idx_lebs
1067          * depend on it. This means we have to initialize it to make sure
1068          * budgeting works properly.
1069          */
1070         c->bi.uncommitted_idx = atomic_long_read(&c->dirty_zn_cnt);
1071         c->bi.uncommitted_idx *= c->max_idx_node_sz;
1072 
1073         ubifs_assert(c->bud_bytes <= c->max_bud_bytes || c->need_recovery);
1074         dbg_mnt("finished, log head LEB %d:%d, max_sqnum %llu, highest_inum %lu",
1075                 c->lhead_lnum, c->lhead_offs, c->max_sqnum,
1076                 (unsigned long)c->highest_inum);
1077 out:
1078         destroy_replay_list(c);
1079         destroy_bud_list(c);
1080         c->replaying = 0;
1081         return err;
1082 }
1083 

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