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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                 c->lhead_offs = 0;
248         }
249 
250         if (c->lhead_offs == 0) {
251                 /* Must ensure next log LEB has been unmapped */
252                 err = ubifs_leb_unmap(c, c->lhead_lnum);
253                 if (err)
254                         goto out_unlock;
255         }
256 
257         if (bud->start == 0) {
258                 /*
259                  * Before writing the LEB reference which refers an empty LEB
260                  * to the log, we have to make sure it is mapped, because
261                  * otherwise we'd risk to refer an LEB with garbage in case of
262                  * an unclean reboot, because the target LEB might have been
263                  * unmapped, but not yet physically erased.
264                  */
265                 err = ubifs_leb_map(c, bud->lnum);
266                 if (err)
267                         goto out_unlock;
268         }
269 
270         dbg_log("write ref LEB %d:%d",
271                 c->lhead_lnum, c->lhead_offs);
272         err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
273                                c->lhead_offs);
274         if (err)
275                 goto out_unlock;
276 
277         c->lhead_offs += c->ref_node_alsz;
278 
279         ubifs_add_bud(c, bud);
280 
281         mutex_unlock(&c->log_mutex);
282         kfree(ref);
283         return 0;
284 
285 out_unlock:
286         mutex_unlock(&c->log_mutex);
287         kfree(ref);
288         kfree(bud);
289         return err;
290 }
291 
292 /**
293  * remove_buds - remove used buds.
294  * @c: UBIFS file-system description object
295  *
296  * This function removes use buds from the buds tree. It does not remove the
297  * buds which are pointed to by journal heads.
298  */
299 static void remove_buds(struct ubifs_info *c)
300 {
301         struct rb_node *p;
302 
303         ubifs_assert(list_empty(&c->old_buds));
304         c->cmt_bud_bytes = 0;
305         spin_lock(&c->buds_lock);
306         p = rb_first(&c->buds);
307         while (p) {
308                 struct rb_node *p1 = p;
309                 struct ubifs_bud *bud;
310                 struct ubifs_wbuf *wbuf;
311 
312                 p = rb_next(p);
313                 bud = rb_entry(p1, struct ubifs_bud, rb);
314                 wbuf = &c->jheads[bud->jhead].wbuf;
315 
316                 if (wbuf->lnum == bud->lnum) {
317                         /*
318                          * Do not remove buds which are pointed to by journal
319                          * heads (non-closed buds).
320                          */
321                         c->cmt_bud_bytes += wbuf->offs - bud->start;
322                         dbg_log("preserve %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
323                                 bud->lnum, bud->start, dbg_jhead(bud->jhead),
324                                 wbuf->offs - bud->start, c->cmt_bud_bytes);
325                         bud->start = wbuf->offs;
326                 } else {
327                         c->cmt_bud_bytes += c->leb_size - bud->start;
328                         dbg_log("remove %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
329                                 bud->lnum, bud->start, dbg_jhead(bud->jhead),
330                                 c->leb_size - bud->start, c->cmt_bud_bytes);
331                         rb_erase(p1, &c->buds);
332                         /*
333                          * If the commit does not finish, the recovery will need
334                          * to replay the journal, in which case the old buds
335                          * must be unchanged. Do not release them until post
336                          * commit i.e. do not allow them to be garbage
337                          * collected.
338                          */
339                         list_move(&bud->list, &c->old_buds);
340                 }
341         }
342         spin_unlock(&c->buds_lock);
343 }
344 
345 /**
346  * ubifs_log_start_commit - start commit.
347  * @c: UBIFS file-system description object
348  * @ltail_lnum: return new log tail LEB number
349  *
350  * The commit operation starts with writing "commit start" node to the log and
351  * reference nodes for all journal heads which will define new journal after
352  * the commit has been finished. The commit start and reference nodes are
353  * written in one go to the nearest empty log LEB (hence, when commit is
354  * finished UBIFS may safely unmap all the previous log LEBs). This function
355  * returns zero in case of success and a negative error code in case of
356  * failure.
357  */
358 int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
359 {
360         void *buf;
361         struct ubifs_cs_node *cs;
362         struct ubifs_ref_node *ref;
363         int err, i, max_len, len;
364 
365         err = dbg_check_bud_bytes(c);
366         if (err)
367                 return err;
368 
369         max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
370         max_len = ALIGN(max_len, c->min_io_size);
371         buf = cs = kmalloc(max_len, GFP_NOFS);
372         if (!buf)
373                 return -ENOMEM;
374 
375         cs->ch.node_type = UBIFS_CS_NODE;
376         cs->cmt_no = cpu_to_le64(c->cmt_no);
377         ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
378 
379         /*
380          * Note, we do not lock 'c->log_mutex' because this is the commit start
381          * phase and we are exclusively using the log. And we do not lock
382          * write-buffer because nobody can write to the file-system at this
383          * phase.
384          */
385 
386         len = UBIFS_CS_NODE_SZ;
387         for (i = 0; i < c->jhead_cnt; i++) {
388                 int lnum = c->jheads[i].wbuf.lnum;
389                 int offs = c->jheads[i].wbuf.offs;
390 
391                 if (lnum == -1 || offs == c->leb_size)
392                         continue;
393 
394                 dbg_log("add ref to LEB %d:%d for jhead %s",
395                         lnum, offs, dbg_jhead(i));
396                 ref = buf + len;
397                 ref->ch.node_type = UBIFS_REF_NODE;
398                 ref->lnum = cpu_to_le32(lnum);
399                 ref->offs = cpu_to_le32(offs);
400                 ref->jhead = cpu_to_le32(i);
401 
402                 ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
403                 len += UBIFS_REF_NODE_SZ;
404         }
405 
406         ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
407 
408         /* Switch to the next log LEB */
409         if (c->lhead_offs) {
410                 c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
411                 c->lhead_offs = 0;
412         }
413 
414         if (c->lhead_offs == 0) {
415                 /* Must ensure next LEB has been unmapped */
416                 err = ubifs_leb_unmap(c, c->lhead_lnum);
417                 if (err)
418                         goto out;
419         }
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 rb_node *this = done_tree->rb_node;
587         struct done_ref *dr;
588 
589         while (this) {
590                 if (this->rb_left) {
591                         this = this->rb_left;
592                         continue;
593                 } else if (this->rb_right) {
594                         this = this->rb_right;
595                         continue;
596                 }
597                 dr = rb_entry(this, struct done_ref, rb);
598                 this = rb_parent(this);
599                 if (this) {
600                         if (this->rb_left == &dr->rb)
601                                 this->rb_left = NULL;
602                         else
603                                 this->rb_right = NULL;
604                 }
605                 kfree(dr);
606         }
607 }
608 
609 /**
610  * add_node - add a node to the consolidated log.
611  * @c: UBIFS file-system description object
612  * @buf: buffer to which to add
613  * @lnum: LEB number to which to write is passed and returned here
614  * @offs: offset to where to write is passed and returned here
615  * @node: node to add
616  *
617  * This function returns %0 on success and a negative error code on failure.
618  */
619 static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
620                     void *node)
621 {
622         struct ubifs_ch *ch = node;
623         int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
624 
625         if (len > remains) {
626                 int sz = ALIGN(*offs, c->min_io_size), err;
627 
628                 ubifs_pad(c, buf + *offs, sz - *offs);
629                 err = ubifs_leb_change(c, *lnum, buf, sz);
630                 if (err)
631                         return err;
632                 *lnum = ubifs_next_log_lnum(c, *lnum);
633                 *offs = 0;
634         }
635         memcpy(buf + *offs, node, len);
636         *offs += ALIGN(len, 8);
637         return 0;
638 }
639 
640 /**
641  * ubifs_consolidate_log - consolidate the log.
642  * @c: UBIFS file-system description object
643  *
644  * Repeated failed commits could cause the log to be full, but at least 1 LEB is
645  * needed for commit. This function rewrites the reference nodes in the log
646  * omitting duplicates, and failed CS nodes, and leaving no gaps.
647  *
648  * This function returns %0 on success and a negative error code on failure.
649  */
650 int ubifs_consolidate_log(struct ubifs_info *c)
651 {
652         struct ubifs_scan_leb *sleb;
653         struct ubifs_scan_node *snod;
654         struct rb_root done_tree = RB_ROOT;
655         int lnum, err, first = 1, write_lnum, offs = 0;
656         void *buf;
657 
658         dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
659                   c->lhead_lnum);
660         buf = vmalloc(c->leb_size);
661         if (!buf)
662                 return -ENOMEM;
663         lnum = c->ltail_lnum;
664         write_lnum = lnum;
665         while (1) {
666                 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
667                 if (IS_ERR(sleb)) {
668                         err = PTR_ERR(sleb);
669                         goto out_free;
670                 }
671                 list_for_each_entry(snod, &sleb->nodes, list) {
672                         switch (snod->type) {
673                         case UBIFS_REF_NODE: {
674                                 struct ubifs_ref_node *ref = snod->node;
675                                 int ref_lnum = le32_to_cpu(ref->lnum);
676 
677                                 err = done_already(&done_tree, ref_lnum);
678                                 if (err < 0)
679                                         goto out_scan;
680                                 if (err != 1) {
681                                         err = add_node(c, buf, &write_lnum,
682                                                        &offs, snod->node);
683                                         if (err)
684                                                 goto out_scan;
685                                 }
686                                 break;
687                         }
688                         case UBIFS_CS_NODE:
689                                 if (!first)
690                                         break;
691                                 err = add_node(c, buf, &write_lnum, &offs,
692                                                snod->node);
693                                 if (err)
694                                         goto out_scan;
695                                 first = 0;
696                                 break;
697                         }
698                 }
699                 ubifs_scan_destroy(sleb);
700                 if (lnum == c->lhead_lnum)
701                         break;
702                 lnum = ubifs_next_log_lnum(c, lnum);
703         }
704         if (offs) {
705                 int sz = ALIGN(offs, c->min_io_size);
706 
707                 ubifs_pad(c, buf + offs, sz - offs);
708                 err = ubifs_leb_change(c, write_lnum, buf, sz);
709                 if (err)
710                         goto out_free;
711                 offs = ALIGN(offs, c->min_io_size);
712         }
713         destroy_done_tree(&done_tree);
714         vfree(buf);
715         if (write_lnum == c->lhead_lnum) {
716                 ubifs_err("log is too full");
717                 return -EINVAL;
718         }
719         /* Unmap remaining LEBs */
720         lnum = write_lnum;
721         do {
722                 lnum = ubifs_next_log_lnum(c, lnum);
723                 err = ubifs_leb_unmap(c, lnum);
724                 if (err)
725                         return err;
726         } while (lnum != c->lhead_lnum);
727         c->lhead_lnum = write_lnum;
728         c->lhead_offs = offs;
729         dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
730         return 0;
731 
732 out_scan:
733         ubifs_scan_destroy(sleb);
734 out_free:
735         destroy_done_tree(&done_tree);
736         vfree(buf);
737         return err;
738 }
739 
740 /**
741  * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
742  * @c: UBIFS file-system description object
743  *
744  * This function makes sure the amount of flash space used by closed buds
745  * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
746  * case of failure.
747  */
748 static int dbg_check_bud_bytes(struct ubifs_info *c)
749 {
750         int i, err = 0;
751         struct ubifs_bud *bud;
752         long long bud_bytes = 0;
753 
754         if (!dbg_is_chk_gen(c))
755                 return 0;
756 
757         spin_lock(&c->buds_lock);
758         for (i = 0; i < c->jhead_cnt; i++)
759                 list_for_each_entry(bud, &c->jheads[i].buds_list, list)
760                         bud_bytes += c->leb_size - bud->start;
761 
762         if (c->bud_bytes != bud_bytes) {
763                 ubifs_err("bad bud_bytes %lld, calculated %lld",
764                           c->bud_bytes, bud_bytes);
765                 err = -EINVAL;
766         }
767         spin_unlock(&c->buds_lock);
768 
769         return err;
770 }
771 

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