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TOMOYO Linux Cross Reference
Linux/fs/ubifs/log.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: Artem Bityutskiy (Битюцкий Артём)
 20  *          Adrian Hunter
 21  */
 22 
 23 /*
 24  * This file is a part of UBIFS journal implementation and contains various
 25  * functions which manipulate the log. The log is a fixed area on the flash
 26  * which does not contain any data but refers to buds. The log is a part of the
 27  * journal.
 28  */
 29 
 30 #include "ubifs.h"
 31 
 32 static int dbg_check_bud_bytes(struct ubifs_info *c);
 33 
 34 /**
 35  * ubifs_search_bud - search bud LEB.
 36  * @c: UBIFS file-system description object
 37  * @lnum: logical eraseblock number to search
 38  *
 39  * This function searches bud LEB @lnum. Returns bud description object in case
 40  * of success and %NULL if there is no bud with this LEB number.
 41  */
 42 struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum)
 43 {
 44         struct rb_node *p;
 45         struct ubifs_bud *bud;
 46 
 47         spin_lock(&c->buds_lock);
 48         p = c->buds.rb_node;
 49         while (p) {
 50                 bud = rb_entry(p, struct ubifs_bud, rb);
 51                 if (lnum < bud->lnum)
 52                         p = p->rb_left;
 53                 else if (lnum > bud->lnum)
 54                         p = p->rb_right;
 55                 else {
 56                         spin_unlock(&c->buds_lock);
 57                         return bud;
 58                 }
 59         }
 60         spin_unlock(&c->buds_lock);
 61         return NULL;
 62 }
 63 
 64 /**
 65  * ubifs_get_wbuf - get the wbuf associated with a LEB, if there is one.
 66  * @c: UBIFS file-system description object
 67  * @lnum: logical eraseblock number to search
 68  *
 69  * This functions returns the wbuf for @lnum or %NULL if there is not one.
 70  */
 71 struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum)
 72 {
 73         struct rb_node *p;
 74         struct ubifs_bud *bud;
 75         int jhead;
 76 
 77         if (!c->jheads)
 78                 return NULL;
 79 
 80         spin_lock(&c->buds_lock);
 81         p = c->buds.rb_node;
 82         while (p) {
 83                 bud = rb_entry(p, struct ubifs_bud, rb);
 84                 if (lnum < bud->lnum)
 85                         p = p->rb_left;
 86                 else if (lnum > bud->lnum)
 87                         p = p->rb_right;
 88                 else {
 89                         jhead = bud->jhead;
 90                         spin_unlock(&c->buds_lock);
 91                         return &c->jheads[jhead].wbuf;
 92                 }
 93         }
 94         spin_unlock(&c->buds_lock);
 95         return NULL;
 96 }
 97 
 98 /**
 99  * empty_log_bytes - calculate amount of empty space in the log.
100  * @c: UBIFS file-system description object
101  */
102 static inline long long empty_log_bytes(const struct ubifs_info *c)
103 {
104         long long h, t;
105 
106         h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs;
107         t = (long long)c->ltail_lnum * c->leb_size;
108 
109         if (h > t)
110                 return c->log_bytes - h + t;
111         else if (h != t)
112                 return t - h;
113         else if (c->lhead_lnum != c->ltail_lnum)
114                 return 0;
115         else
116                 return c->log_bytes;
117 }
118 
119 /**
120  * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list.
121  * @c: UBIFS file-system description object
122  * @bud: the bud to add
123  */
124 void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud)
125 {
126         struct rb_node **p, *parent = NULL;
127         struct ubifs_bud *b;
128         struct ubifs_jhead *jhead;
129 
130         spin_lock(&c->buds_lock);
131         p = &c->buds.rb_node;
132         while (*p) {
133                 parent = *p;
134                 b = rb_entry(parent, struct ubifs_bud, rb);
135                 ubifs_assert(bud->lnum != b->lnum);
136                 if (bud->lnum < b->lnum)
137                         p = &(*p)->rb_left;
138                 else
139                         p = &(*p)->rb_right;
140         }
141 
142         rb_link_node(&bud->rb, parent, p);
143         rb_insert_color(&bud->rb, &c->buds);
144         if (c->jheads) {
145                 jhead = &c->jheads[bud->jhead];
146                 list_add_tail(&bud->list, &jhead->buds_list);
147         } else
148                 ubifs_assert(c->replaying && c->ro_mount);
149 
150         /*
151          * Note, although this is a new bud, we anyway account this space now,
152          * before any data has been written to it, because this is about to
153          * guarantee fixed mount time, and this bud will anyway be read and
154          * scanned.
155          */
156         c->bud_bytes += c->leb_size - bud->start;
157 
158         dbg_log("LEB %d:%d, jhead %s, bud_bytes %lld", bud->lnum,
159                 bud->start, dbg_jhead(bud->jhead), c->bud_bytes);
160         spin_unlock(&c->buds_lock);
161 }
162 
163 /**
164  * ubifs_add_bud_to_log - add a new bud to the log.
165  * @c: UBIFS file-system description object
166  * @jhead: journal head the bud belongs to
167  * @lnum: LEB number of the bud
168  * @offs: starting offset of the bud
169  *
170  * This function writes reference node for the new bud LEB @lnum it to the log,
171  * and adds it to the buds tress. It also makes sure that log size does not
172  * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success,
173  * %-EAGAIN if commit is required, and a negative error codes in case of
174  * failure.
175  */
176 int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)
177 {
178         int err;
179         struct ubifs_bud *bud;
180         struct ubifs_ref_node *ref;
181 
182         bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS);
183         if (!bud)
184                 return -ENOMEM;
185         ref = kzalloc(c->ref_node_alsz, GFP_NOFS);
186         if (!ref) {
187                 kfree(bud);
188                 return -ENOMEM;
189         }
190 
191         mutex_lock(&c->log_mutex);
192         ubifs_assert(!c->ro_media && !c->ro_mount);
193         if (c->ro_error) {
194                 err = -EROFS;
195                 goto out_unlock;
196         }
197 
198         /* Make sure we have enough space in the log */
199         if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
200                 dbg_log("not enough log space - %lld, required %d",
201                         empty_log_bytes(c), c->min_log_bytes);
202                 ubifs_commit_required(c);
203                 err = -EAGAIN;
204                 goto out_unlock;
205         }
206 
207         /*
208          * Make sure the amount of space in buds will not exceed the
209          * 'c->max_bud_bytes' limit, because we want to guarantee mount time
210          * limits.
211          *
212          * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
213          * because we are holding @c->log_mutex. All @c->bud_bytes take place
214          * when both @c->log_mutex and @c->bud_bytes are locked.
215          */
216         if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
217                 dbg_log("bud bytes %lld (%lld max), require commit",
218                         c->bud_bytes, c->max_bud_bytes);
219                 ubifs_commit_required(c);
220                 err = -EAGAIN;
221                 goto out_unlock;
222         }
223 
224         /*
225          * If the journal is full enough - start background commit. Note, it is
226          * OK to read 'c->cmt_state' without spinlock because integer reads
227          * are atomic in the kernel.
228          */
229         if (c->bud_bytes >= c->bg_bud_bytes &&
230             c->cmt_state == COMMIT_RESTING) {
231                 dbg_log("bud bytes %lld (%lld max), initiate BG commit",
232                         c->bud_bytes, c->max_bud_bytes);
233                 ubifs_request_bg_commit(c);
234         }
235 
236         bud->lnum = lnum;
237         bud->start = offs;
238         bud->jhead = jhead;
239 
240         ref->ch.node_type = UBIFS_REF_NODE;
241         ref->lnum = cpu_to_le32(bud->lnum);
242         ref->offs = cpu_to_le32(bud->start);
243         ref->jhead = cpu_to_le32(jhead);
244 
245         if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
246                 c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
247                 ubifs_assert(c->lhead_lnum != c->ltail_lnum);
248                 c->lhead_offs = 0;
249         }
250 
251         if (c->lhead_offs == 0) {
252                 /* Must ensure next log LEB has been unmapped */
253                 err = ubifs_leb_unmap(c, c->lhead_lnum);
254                 if (err)
255                         goto out_unlock;
256         }
257 
258         if (bud->start == 0) {
259                 /*
260                  * Before writing the LEB reference which refers an empty LEB
261                  * to the log, we have to make sure it is mapped, because
262                  * otherwise we'd risk to refer an LEB with garbage in case of
263                  * an unclean reboot, because the target LEB might have been
264                  * unmapped, but not yet physically erased.
265                  */
266                 err = ubifs_leb_map(c, bud->lnum);
267                 if (err)
268                         goto out_unlock;
269         }
270 
271         dbg_log("write ref LEB %d:%d",
272                 c->lhead_lnum, c->lhead_offs);
273         err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
274                                c->lhead_offs);
275         if (err)
276                 goto out_unlock;
277 
278         c->lhead_offs += c->ref_node_alsz;
279 
280         ubifs_add_bud(c, bud);
281 
282         mutex_unlock(&c->log_mutex);
283         kfree(ref);
284         return 0;
285 
286 out_unlock:
287         mutex_unlock(&c->log_mutex);
288         kfree(ref);
289         kfree(bud);
290         return err;
291 }
292 
293 /**
294  * remove_buds - remove used buds.
295  * @c: UBIFS file-system description object
296  *
297  * This function removes use buds from the buds tree. It does not remove the
298  * buds which are pointed to by journal heads.
299  */
300 static void remove_buds(struct ubifs_info *c)
301 {
302         struct rb_node *p;
303 
304         ubifs_assert(list_empty(&c->old_buds));
305         c->cmt_bud_bytes = 0;
306         spin_lock(&c->buds_lock);
307         p = rb_first(&c->buds);
308         while (p) {
309                 struct rb_node *p1 = p;
310                 struct ubifs_bud *bud;
311                 struct ubifs_wbuf *wbuf;
312 
313                 p = rb_next(p);
314                 bud = rb_entry(p1, struct ubifs_bud, rb);
315                 wbuf = &c->jheads[bud->jhead].wbuf;
316 
317                 if (wbuf->lnum == bud->lnum) {
318                         /*
319                          * Do not remove buds which are pointed to by journal
320                          * heads (non-closed buds).
321                          */
322                         c->cmt_bud_bytes += wbuf->offs - bud->start;
323                         dbg_log("preserve %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
324                                 bud->lnum, bud->start, dbg_jhead(bud->jhead),
325                                 wbuf->offs - bud->start, c->cmt_bud_bytes);
326                         bud->start = wbuf->offs;
327                 } else {
328                         c->cmt_bud_bytes += c->leb_size - bud->start;
329                         dbg_log("remove %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
330                                 bud->lnum, bud->start, dbg_jhead(bud->jhead),
331                                 c->leb_size - bud->start, c->cmt_bud_bytes);
332                         rb_erase(p1, &c->buds);
333                         /*
334                          * If the commit does not finish, the recovery will need
335                          * to replay the journal, in which case the old buds
336                          * must be unchanged. Do not release them until post
337                          * commit i.e. do not allow them to be garbage
338                          * collected.
339                          */
340                         list_move(&bud->list, &c->old_buds);
341                 }
342         }
343         spin_unlock(&c->buds_lock);
344 }
345 
346 /**
347  * ubifs_log_start_commit - start commit.
348  * @c: UBIFS file-system description object
349  * @ltail_lnum: return new log tail LEB number
350  *
351  * The commit operation starts with writing "commit start" node to the log and
352  * reference nodes for all journal heads which will define new journal after
353  * the commit has been finished. The commit start and reference nodes are
354  * written in one go to the nearest empty log LEB (hence, when commit is
355  * finished UBIFS may safely unmap all the previous log LEBs). This function
356  * returns zero in case of success and a negative error code in case of
357  * failure.
358  */
359 int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
360 {
361         void *buf;
362         struct ubifs_cs_node *cs;
363         struct ubifs_ref_node *ref;
364         int err, i, max_len, len;
365 
366         err = dbg_check_bud_bytes(c);
367         if (err)
368                 return err;
369 
370         max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
371         max_len = ALIGN(max_len, c->min_io_size);
372         buf = cs = kmalloc(max_len, GFP_NOFS);
373         if (!buf)
374                 return -ENOMEM;
375 
376         cs->ch.node_type = UBIFS_CS_NODE;
377         cs->cmt_no = cpu_to_le64(c->cmt_no);
378         ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
379 
380         /*
381          * Note, we do not lock 'c->log_mutex' because this is the commit start
382          * phase and we are exclusively using the log. And we do not lock
383          * write-buffer because nobody can write to the file-system at this
384          * phase.
385          */
386 
387         len = UBIFS_CS_NODE_SZ;
388         for (i = 0; i < c->jhead_cnt; i++) {
389                 int lnum = c->jheads[i].wbuf.lnum;
390                 int offs = c->jheads[i].wbuf.offs;
391 
392                 if (lnum == -1 || offs == c->leb_size)
393                         continue;
394 
395                 dbg_log("add ref to LEB %d:%d for jhead %s",
396                         lnum, offs, dbg_jhead(i));
397                 ref = buf + len;
398                 ref->ch.node_type = UBIFS_REF_NODE;
399                 ref->lnum = cpu_to_le32(lnum);
400                 ref->offs = cpu_to_le32(offs);
401                 ref->jhead = cpu_to_le32(i);
402 
403                 ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
404                 len += UBIFS_REF_NODE_SZ;
405         }
406 
407         ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
408 
409         /* Switch to the next log LEB */
410         if (c->lhead_offs) {
411                 c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
412                 ubifs_assert(c->lhead_lnum != c->ltail_lnum);
413                 c->lhead_offs = 0;
414         }
415 
416         /* Must ensure next LEB has been unmapped */
417         err = ubifs_leb_unmap(c, c->lhead_lnum);
418         if (err)
419                 goto out;
420 
421         len = ALIGN(len, c->min_io_size);
422         dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
423         err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len);
424         if (err)
425                 goto out;
426 
427         *ltail_lnum = c->lhead_lnum;
428 
429         c->lhead_offs += len;
430         if (c->lhead_offs == c->leb_size) {
431                 c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
432                 c->lhead_offs = 0;
433         }
434 
435         remove_buds(c);
436 
437         /*
438          * We have started the commit and now users may use the rest of the log
439          * for new writes.
440          */
441         c->min_log_bytes = 0;
442 
443 out:
444         kfree(buf);
445         return err;
446 }
447 
448 /**
449  * ubifs_log_end_commit - end commit.
450  * @c: UBIFS file-system description object
451  * @ltail_lnum: new log tail LEB number
452  *
453  * This function is called on when the commit operation was finished. It
454  * moves log tail to new position and updates the master node so that it stores
455  * the new log tail LEB number. Returns zero in case of success and a negative
456  * error code in case of failure.
457  */
458 int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
459 {
460         int err;
461 
462         /*
463          * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS
464          * writes during commit. Its only short "commit" start phase when
465          * writers are blocked.
466          */
467         mutex_lock(&c->log_mutex);
468 
469         dbg_log("old tail was LEB %d:0, new tail is LEB %d:0",
470                 c->ltail_lnum, ltail_lnum);
471 
472         c->ltail_lnum = ltail_lnum;
473         /*
474          * The commit is finished and from now on it must be guaranteed that
475          * there is always enough space for the next commit.
476          */
477         c->min_log_bytes = c->leb_size;
478 
479         spin_lock(&c->buds_lock);
480         c->bud_bytes -= c->cmt_bud_bytes;
481         spin_unlock(&c->buds_lock);
482 
483         err = dbg_check_bud_bytes(c);
484         if (err)
485                 goto out;
486 
487         err = ubifs_write_master(c);
488 
489 out:
490         mutex_unlock(&c->log_mutex);
491         return err;
492 }
493 
494 /**
495  * ubifs_log_post_commit - things to do after commit is completed.
496  * @c: UBIFS file-system description object
497  * @old_ltail_lnum: old log tail LEB number
498  *
499  * Release buds only after commit is completed, because they must be unchanged
500  * if recovery is needed.
501  *
502  * Unmap log LEBs only after commit is completed, because they may be needed for
503  * recovery.
504  *
505  * This function returns %0 on success and a negative error code on failure.
506  */
507 int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum)
508 {
509         int lnum, err = 0;
510 
511         while (!list_empty(&c->old_buds)) {
512                 struct ubifs_bud *bud;
513 
514                 bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
515                 err = ubifs_return_leb(c, bud->lnum);
516                 if (err)
517                         return err;
518                 list_del(&bud->list);
519                 kfree(bud);
520         }
521         mutex_lock(&c->log_mutex);
522         for (lnum = old_ltail_lnum; lnum != c->ltail_lnum;
523              lnum = ubifs_next_log_lnum(c, lnum)) {
524                 dbg_log("unmap log LEB %d", lnum);
525                 err = ubifs_leb_unmap(c, lnum);
526                 if (err)
527                         goto out;
528         }
529 out:
530         mutex_unlock(&c->log_mutex);
531         return err;
532 }
533 
534 /**
535  * struct done_ref - references that have been done.
536  * @rb: rb-tree node
537  * @lnum: LEB number
538  */
539 struct done_ref {
540         struct rb_node rb;
541         int lnum;
542 };
543 
544 /**
545  * done_already - determine if a reference has been done already.
546  * @done_tree: rb-tree to store references that have been done
547  * @lnum: LEB number of reference
548  *
549  * This function returns %1 if the reference has been done, %0 if not, otherwise
550  * a negative error code is returned.
551  */
552 static int done_already(struct rb_root *done_tree, int lnum)
553 {
554         struct rb_node **p = &done_tree->rb_node, *parent = NULL;
555         struct done_ref *dr;
556 
557         while (*p) {
558                 parent = *p;
559                 dr = rb_entry(parent, struct done_ref, rb);
560                 if (lnum < dr->lnum)
561                         p = &(*p)->rb_left;
562                 else if (lnum > dr->lnum)
563                         p = &(*p)->rb_right;
564                 else
565                         return 1;
566         }
567 
568         dr = kzalloc(sizeof(struct done_ref), GFP_NOFS);
569         if (!dr)
570                 return -ENOMEM;
571 
572         dr->lnum = lnum;
573 
574         rb_link_node(&dr->rb, parent, p);
575         rb_insert_color(&dr->rb, done_tree);
576 
577         return 0;
578 }
579 
580 /**
581  * destroy_done_tree - destroy the done tree.
582  * @done_tree: done tree to destroy
583  */
584 static void destroy_done_tree(struct rb_root *done_tree)
585 {
586         struct done_ref *dr, *n;
587 
588         rbtree_postorder_for_each_entry_safe(dr, n, done_tree, rb)
589                 kfree(dr);
590 }
591 
592 /**
593  * add_node - add a node to the consolidated log.
594  * @c: UBIFS file-system description object
595  * @buf: buffer to which to add
596  * @lnum: LEB number to which to write is passed and returned here
597  * @offs: offset to where to write is passed and returned here
598  * @node: node to add
599  *
600  * This function returns %0 on success and a negative error code on failure.
601  */
602 static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
603                     void *node)
604 {
605         struct ubifs_ch *ch = node;
606         int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
607 
608         if (len > remains) {
609                 int sz = ALIGN(*offs, c->min_io_size), err;
610 
611                 ubifs_pad(c, buf + *offs, sz - *offs);
612                 err = ubifs_leb_change(c, *lnum, buf, sz);
613                 if (err)
614                         return err;
615                 *lnum = ubifs_next_log_lnum(c, *lnum);
616                 *offs = 0;
617         }
618         memcpy(buf + *offs, node, len);
619         *offs += ALIGN(len, 8);
620         return 0;
621 }
622 
623 /**
624  * ubifs_consolidate_log - consolidate the log.
625  * @c: UBIFS file-system description object
626  *
627  * Repeated failed commits could cause the log to be full, but at least 1 LEB is
628  * needed for commit. This function rewrites the reference nodes in the log
629  * omitting duplicates, and failed CS nodes, and leaving no gaps.
630  *
631  * This function returns %0 on success and a negative error code on failure.
632  */
633 int ubifs_consolidate_log(struct ubifs_info *c)
634 {
635         struct ubifs_scan_leb *sleb;
636         struct ubifs_scan_node *snod;
637         struct rb_root done_tree = RB_ROOT;
638         int lnum, err, first = 1, write_lnum, offs = 0;
639         void *buf;
640 
641         dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
642                   c->lhead_lnum);
643         buf = vmalloc(c->leb_size);
644         if (!buf)
645                 return -ENOMEM;
646         lnum = c->ltail_lnum;
647         write_lnum = lnum;
648         while (1) {
649                 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
650                 if (IS_ERR(sleb)) {
651                         err = PTR_ERR(sleb);
652                         goto out_free;
653                 }
654                 list_for_each_entry(snod, &sleb->nodes, list) {
655                         switch (snod->type) {
656                         case UBIFS_REF_NODE: {
657                                 struct ubifs_ref_node *ref = snod->node;
658                                 int ref_lnum = le32_to_cpu(ref->lnum);
659 
660                                 err = done_already(&done_tree, ref_lnum);
661                                 if (err < 0)
662                                         goto out_scan;
663                                 if (err != 1) {
664                                         err = add_node(c, buf, &write_lnum,
665                                                        &offs, snod->node);
666                                         if (err)
667                                                 goto out_scan;
668                                 }
669                                 break;
670                         }
671                         case UBIFS_CS_NODE:
672                                 if (!first)
673                                         break;
674                                 err = add_node(c, buf, &write_lnum, &offs,
675                                                snod->node);
676                                 if (err)
677                                         goto out_scan;
678                                 first = 0;
679                                 break;
680                         }
681                 }
682                 ubifs_scan_destroy(sleb);
683                 if (lnum == c->lhead_lnum)
684                         break;
685                 lnum = ubifs_next_log_lnum(c, lnum);
686         }
687         if (offs) {
688                 int sz = ALIGN(offs, c->min_io_size);
689 
690                 ubifs_pad(c, buf + offs, sz - offs);
691                 err = ubifs_leb_change(c, write_lnum, buf, sz);
692                 if (err)
693                         goto out_free;
694                 offs = ALIGN(offs, c->min_io_size);
695         }
696         destroy_done_tree(&done_tree);
697         vfree(buf);
698         if (write_lnum == c->lhead_lnum) {
699                 ubifs_err(c, "log is too full");
700                 return -EINVAL;
701         }
702         /* Unmap remaining LEBs */
703         lnum = write_lnum;
704         do {
705                 lnum = ubifs_next_log_lnum(c, lnum);
706                 err = ubifs_leb_unmap(c, lnum);
707                 if (err)
708                         return err;
709         } while (lnum != c->lhead_lnum);
710         c->lhead_lnum = write_lnum;
711         c->lhead_offs = offs;
712         dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
713         return 0;
714 
715 out_scan:
716         ubifs_scan_destroy(sleb);
717 out_free:
718         destroy_done_tree(&done_tree);
719         vfree(buf);
720         return err;
721 }
722 
723 /**
724  * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
725  * @c: UBIFS file-system description object
726  *
727  * This function makes sure the amount of flash space used by closed buds
728  * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
729  * case of failure.
730  */
731 static int dbg_check_bud_bytes(struct ubifs_info *c)
732 {
733         int i, err = 0;
734         struct ubifs_bud *bud;
735         long long bud_bytes = 0;
736 
737         if (!dbg_is_chk_gen(c))
738                 return 0;
739 
740         spin_lock(&c->buds_lock);
741         for (i = 0; i < c->jhead_cnt; i++)
742                 list_for_each_entry(bud, &c->jheads[i].buds_list, list)
743                         bud_bytes += c->leb_size - bud->start;
744 
745         if (c->bud_bytes != bud_bytes) {
746                 ubifs_err(c, "bad bud_bytes %lld, calculated %lld",
747                           c->bud_bytes, bud_bytes);
748                 err = -EINVAL;
749         }
750         spin_unlock(&c->buds_lock);
751 
752         return err;
753 }
754 

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