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

Version: ~ [ linux-5.5-rc7 ] ~ [ linux-5.4.13 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.97 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.166 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.210 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.210 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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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 implements functions that manage the running of the commit process.
 25  * Each affected module has its own functions to accomplish their part in the
 26  * commit and those functions are called here.
 27  *
 28  * The commit is the process whereby all updates to the index and LEB properties
 29  * are written out together and the journal becomes empty. This keeps the
 30  * file system consistent - at all times the state can be recreated by reading
 31  * the index and LEB properties and then replaying the journal.
 32  *
 33  * The commit is split into two parts named "commit start" and "commit end".
 34  * During commit start, the commit process has exclusive access to the journal
 35  * by holding the commit semaphore down for writing. As few I/O operations as
 36  * possible are performed during commit start, instead the nodes that are to be
 37  * written are merely identified. During commit end, the commit semaphore is no
 38  * longer held and the journal is again in operation, allowing users to continue
 39  * to use the file system while the bulk of the commit I/O is performed. The
 40  * purpose of this two-step approach is to prevent the commit from causing any
 41  * latency blips. Note that in any case, the commit does not prevent lookups
 42  * (as permitted by the TNC mutex), or access to VFS data structures e.g. page
 43  * cache.
 44  */
 45 
 46 #include <linux/freezer.h>
 47 #include <linux/kthread.h>
 48 #include <linux/slab.h>
 49 #include "ubifs.h"
 50 
 51 /*
 52  * nothing_to_commit - check if there is nothing to commit.
 53  * @c: UBIFS file-system description object
 54  *
 55  * This is a helper function which checks if there is anything to commit. It is
 56  * used as an optimization to avoid starting the commit if it is not really
 57  * necessary. Indeed, the commit operation always assumes flash I/O (e.g.,
 58  * writing the commit start node to the log), and it is better to avoid doing
 59  * this unnecessarily. E.g., 'ubifs_sync_fs()' runs the commit, but if there is
 60  * nothing to commit, it is more optimal to avoid any flash I/O.
 61  *
 62  * This function has to be called with @c->commit_sem locked for writing -
 63  * this function does not take LPT/TNC locks because the @c->commit_sem
 64  * guarantees that we have exclusive access to the TNC and LPT data structures.
 65  *
 66  * This function returns %1 if there is nothing to commit and %0 otherwise.
 67  */
 68 static int nothing_to_commit(struct ubifs_info *c)
 69 {
 70         /*
 71          * During mounting or remounting from R/O mode to R/W mode we may
 72          * commit for various recovery-related reasons.
 73          */
 74         if (c->mounting || c->remounting_rw)
 75                 return 0;
 76 
 77         /*
 78          * If the root TNC node is dirty, we definitely have something to
 79          * commit.
 80          */
 81         if (c->zroot.znode && ubifs_zn_dirty(c->zroot.znode))
 82                 return 0;
 83 
 84         /*
 85          * Even though the TNC is clean, the LPT tree may have dirty nodes. For
 86          * example, this may happen if the budgeting subsystem invoked GC to
 87          * make some free space, and the GC found an LEB with only dirty and
 88          * free space. In this case GC would just change the lprops of this
 89          * LEB (by turning all space into free space) and unmap it.
 90          */
 91         if (c->nroot && test_bit(DIRTY_CNODE, &c->nroot->flags))
 92                 return 0;
 93 
 94         ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0);
 95         ubifs_assert(c->dirty_pn_cnt == 0);
 96         ubifs_assert(c->dirty_nn_cnt == 0);
 97 
 98         return 1;
 99 }
100 
101 /**
102  * do_commit - commit the journal.
103  * @c: UBIFS file-system description object
104  *
105  * This function implements UBIFS commit. It has to be called with commit lock
106  * locked. Returns zero in case of success and a negative error code in case of
107  * failure.
108  */
109 static int do_commit(struct ubifs_info *c)
110 {
111         int err, new_ltail_lnum, old_ltail_lnum, i;
112         struct ubifs_zbranch zroot;
113         struct ubifs_lp_stats lst;
114 
115         dbg_cmt("start");
116         ubifs_assert(!c->ro_media && !c->ro_mount);
117 
118         if (c->ro_error) {
119                 err = -EROFS;
120                 goto out_up;
121         }
122 
123         if (nothing_to_commit(c)) {
124                 up_write(&c->commit_sem);
125                 err = 0;
126                 goto out_cancel;
127         }
128 
129         /* Sync all write buffers (necessary for recovery) */
130         for (i = 0; i < c->jhead_cnt; i++) {
131                 err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
132                 if (err)
133                         goto out_up;
134         }
135 
136         c->cmt_no += 1;
137         err = ubifs_gc_start_commit(c);
138         if (err)
139                 goto out_up;
140         err = dbg_check_lprops(c);
141         if (err)
142                 goto out_up;
143         err = ubifs_log_start_commit(c, &new_ltail_lnum);
144         if (err)
145                 goto out_up;
146         err = ubifs_tnc_start_commit(c, &zroot);
147         if (err)
148                 goto out_up;
149         err = ubifs_lpt_start_commit(c);
150         if (err)
151                 goto out_up;
152         err = ubifs_orphan_start_commit(c);
153         if (err)
154                 goto out_up;
155 
156         ubifs_get_lp_stats(c, &lst);
157 
158         up_write(&c->commit_sem);
159 
160         err = ubifs_tnc_end_commit(c);
161         if (err)
162                 goto out;
163         err = ubifs_lpt_end_commit(c);
164         if (err)
165                 goto out;
166         err = ubifs_orphan_end_commit(c);
167         if (err)
168                 goto out;
169         old_ltail_lnum = c->ltail_lnum;
170         err = ubifs_log_end_commit(c, new_ltail_lnum);
171         if (err)
172                 goto out;
173         err = dbg_check_old_index(c, &zroot);
174         if (err)
175                 goto out;
176 
177         mutex_lock(&c->mst_mutex);
178         c->mst_node->cmt_no      = cpu_to_le64(c->cmt_no);
179         c->mst_node->log_lnum    = cpu_to_le32(new_ltail_lnum);
180         c->mst_node->root_lnum   = cpu_to_le32(zroot.lnum);
181         c->mst_node->root_offs   = cpu_to_le32(zroot.offs);
182         c->mst_node->root_len    = cpu_to_le32(zroot.len);
183         c->mst_node->ihead_lnum  = cpu_to_le32(c->ihead_lnum);
184         c->mst_node->ihead_offs  = cpu_to_le32(c->ihead_offs);
185         c->mst_node->index_size  = cpu_to_le64(c->bi.old_idx_sz);
186         c->mst_node->lpt_lnum    = cpu_to_le32(c->lpt_lnum);
187         c->mst_node->lpt_offs    = cpu_to_le32(c->lpt_offs);
188         c->mst_node->nhead_lnum  = cpu_to_le32(c->nhead_lnum);
189         c->mst_node->nhead_offs  = cpu_to_le32(c->nhead_offs);
190         c->mst_node->ltab_lnum   = cpu_to_le32(c->ltab_lnum);
191         c->mst_node->ltab_offs   = cpu_to_le32(c->ltab_offs);
192         c->mst_node->lsave_lnum  = cpu_to_le32(c->lsave_lnum);
193         c->mst_node->lsave_offs  = cpu_to_le32(c->lsave_offs);
194         c->mst_node->lscan_lnum  = cpu_to_le32(c->lscan_lnum);
195         c->mst_node->empty_lebs  = cpu_to_le32(lst.empty_lebs);
196         c->mst_node->idx_lebs    = cpu_to_le32(lst.idx_lebs);
197         c->mst_node->total_free  = cpu_to_le64(lst.total_free);
198         c->mst_node->total_dirty = cpu_to_le64(lst.total_dirty);
199         c->mst_node->total_used  = cpu_to_le64(lst.total_used);
200         c->mst_node->total_dead  = cpu_to_le64(lst.total_dead);
201         c->mst_node->total_dark  = cpu_to_le64(lst.total_dark);
202         if (c->no_orphs)
203                 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
204         else
205                 c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_NO_ORPHS);
206         err = ubifs_write_master(c);
207         mutex_unlock(&c->mst_mutex);
208         if (err)
209                 goto out;
210 
211         err = ubifs_log_post_commit(c, old_ltail_lnum);
212         if (err)
213                 goto out;
214         err = ubifs_gc_end_commit(c);
215         if (err)
216                 goto out;
217         err = ubifs_lpt_post_commit(c);
218         if (err)
219                 goto out;
220 
221 out_cancel:
222         spin_lock(&c->cs_lock);
223         c->cmt_state = COMMIT_RESTING;
224         wake_up(&c->cmt_wq);
225         dbg_cmt("commit end");
226         spin_unlock(&c->cs_lock);
227         return 0;
228 
229 out_up:
230         up_write(&c->commit_sem);
231 out:
232         ubifs_err("commit failed, error %d", err);
233         spin_lock(&c->cs_lock);
234         c->cmt_state = COMMIT_BROKEN;
235         wake_up(&c->cmt_wq);
236         spin_unlock(&c->cs_lock);
237         ubifs_ro_mode(c, err);
238         return err;
239 }
240 
241 /**
242  * run_bg_commit - run background commit if it is needed.
243  * @c: UBIFS file-system description object
244  *
245  * This function runs background commit if it is needed. Returns zero in case
246  * of success and a negative error code in case of failure.
247  */
248 static int run_bg_commit(struct ubifs_info *c)
249 {
250         spin_lock(&c->cs_lock);
251         /*
252          * Run background commit only if background commit was requested or if
253          * commit is required.
254          */
255         if (c->cmt_state != COMMIT_BACKGROUND &&
256             c->cmt_state != COMMIT_REQUIRED)
257                 goto out;
258         spin_unlock(&c->cs_lock);
259 
260         down_write(&c->commit_sem);
261         spin_lock(&c->cs_lock);
262         if (c->cmt_state == COMMIT_REQUIRED)
263                 c->cmt_state = COMMIT_RUNNING_REQUIRED;
264         else if (c->cmt_state == COMMIT_BACKGROUND)
265                 c->cmt_state = COMMIT_RUNNING_BACKGROUND;
266         else
267                 goto out_cmt_unlock;
268         spin_unlock(&c->cs_lock);
269 
270         return do_commit(c);
271 
272 out_cmt_unlock:
273         up_write(&c->commit_sem);
274 out:
275         spin_unlock(&c->cs_lock);
276         return 0;
277 }
278 
279 /**
280  * ubifs_bg_thread - UBIFS background thread function.
281  * @info: points to the file-system description object
282  *
283  * This function implements various file-system background activities:
284  * o when a write-buffer timer expires it synchronizes the appropriate
285  *   write-buffer;
286  * o when the journal is about to be full, it starts in-advance commit.
287  *
288  * Note, other stuff like background garbage collection may be added here in
289  * future.
290  */
291 int ubifs_bg_thread(void *info)
292 {
293         int err;
294         struct ubifs_info *c = info;
295 
296         dbg_msg("background thread \"%s\" started, PID %d",
297                 c->bgt_name, current->pid);
298         set_freezable();
299 
300         while (1) {
301                 if (kthread_should_stop())
302                         break;
303 
304                 if (try_to_freeze())
305                         continue;
306 
307                 set_current_state(TASK_INTERRUPTIBLE);
308                 /* Check if there is something to do */
309                 if (!c->need_bgt) {
310                         /*
311                          * Nothing prevents us from going sleep now and
312                          * be never woken up and block the task which
313                          * could wait in 'kthread_stop()' forever.
314                          */
315                         if (kthread_should_stop())
316                                 break;
317                         schedule();
318                         continue;
319                 } else
320                         __set_current_state(TASK_RUNNING);
321 
322                 c->need_bgt = 0;
323                 err = ubifs_bg_wbufs_sync(c);
324                 if (err)
325                         ubifs_ro_mode(c, err);
326 
327                 run_bg_commit(c);
328                 cond_resched();
329         }
330 
331         dbg_msg("background thread \"%s\" stops", c->bgt_name);
332         return 0;
333 }
334 
335 /**
336  * ubifs_commit_required - set commit state to "required".
337  * @c: UBIFS file-system description object
338  *
339  * This function is called if a commit is required but cannot be done from the
340  * calling function, so it is just flagged instead.
341  */
342 void ubifs_commit_required(struct ubifs_info *c)
343 {
344         spin_lock(&c->cs_lock);
345         switch (c->cmt_state) {
346         case COMMIT_RESTING:
347         case COMMIT_BACKGROUND:
348                 dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
349                         dbg_cstate(COMMIT_REQUIRED));
350                 c->cmt_state = COMMIT_REQUIRED;
351                 break;
352         case COMMIT_RUNNING_BACKGROUND:
353                 dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
354                         dbg_cstate(COMMIT_RUNNING_REQUIRED));
355                 c->cmt_state = COMMIT_RUNNING_REQUIRED;
356                 break;
357         case COMMIT_REQUIRED:
358         case COMMIT_RUNNING_REQUIRED:
359         case COMMIT_BROKEN:
360                 break;
361         }
362         spin_unlock(&c->cs_lock);
363 }
364 
365 /**
366  * ubifs_request_bg_commit - notify the background thread to do a commit.
367  * @c: UBIFS file-system description object
368  *
369  * This function is called if the journal is full enough to make a commit
370  * worthwhile, so background thread is kicked to start it.
371  */
372 void ubifs_request_bg_commit(struct ubifs_info *c)
373 {
374         spin_lock(&c->cs_lock);
375         if (c->cmt_state == COMMIT_RESTING) {
376                 dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
377                         dbg_cstate(COMMIT_BACKGROUND));
378                 c->cmt_state = COMMIT_BACKGROUND;
379                 spin_unlock(&c->cs_lock);
380                 ubifs_wake_up_bgt(c);
381         } else
382                 spin_unlock(&c->cs_lock);
383 }
384 
385 /**
386  * wait_for_commit - wait for commit.
387  * @c: UBIFS file-system description object
388  *
389  * This function sleeps until the commit operation is no longer running.
390  */
391 static int wait_for_commit(struct ubifs_info *c)
392 {
393         dbg_cmt("pid %d goes sleep", current->pid);
394 
395         /*
396          * The following sleeps if the condition is false, and will be woken
397          * when the commit ends. It is possible, although very unlikely, that we
398          * will wake up and see the subsequent commit running, rather than the
399          * one we were waiting for, and go back to sleep.  However, we will be
400          * woken again, so there is no danger of sleeping forever.
401          */
402         wait_event(c->cmt_wq, c->cmt_state != COMMIT_RUNNING_BACKGROUND &&
403                               c->cmt_state != COMMIT_RUNNING_REQUIRED);
404         dbg_cmt("commit finished, pid %d woke up", current->pid);
405         return 0;
406 }
407 
408 /**
409  * ubifs_run_commit - run or wait for commit.
410  * @c: UBIFS file-system description object
411  *
412  * This function runs commit and returns zero in case of success and a negative
413  * error code in case of failure.
414  */
415 int ubifs_run_commit(struct ubifs_info *c)
416 {
417         int err = 0;
418 
419         spin_lock(&c->cs_lock);
420         if (c->cmt_state == COMMIT_BROKEN) {
421                 err = -EROFS;
422                 goto out;
423         }
424 
425         if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
426                 /*
427                  * We set the commit state to 'running required' to indicate
428                  * that we want it to complete as quickly as possible.
429                  */
430                 c->cmt_state = COMMIT_RUNNING_REQUIRED;
431 
432         if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
433                 spin_unlock(&c->cs_lock);
434                 return wait_for_commit(c);
435         }
436         spin_unlock(&c->cs_lock);
437 
438         /* Ok, the commit is indeed needed */
439 
440         down_write(&c->commit_sem);
441         spin_lock(&c->cs_lock);
442         /*
443          * Since we unlocked 'c->cs_lock', the state may have changed, so
444          * re-check it.
445          */
446         if (c->cmt_state == COMMIT_BROKEN) {
447                 err = -EROFS;
448                 goto out_cmt_unlock;
449         }
450 
451         if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
452                 c->cmt_state = COMMIT_RUNNING_REQUIRED;
453 
454         if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
455                 up_write(&c->commit_sem);
456                 spin_unlock(&c->cs_lock);
457                 return wait_for_commit(c);
458         }
459         c->cmt_state = COMMIT_RUNNING_REQUIRED;
460         spin_unlock(&c->cs_lock);
461 
462         err = do_commit(c);
463         return err;
464 
465 out_cmt_unlock:
466         up_write(&c->commit_sem);
467 out:
468         spin_unlock(&c->cs_lock);
469         return err;
470 }
471 
472 /**
473  * ubifs_gc_should_commit - determine if it is time for GC to run commit.
474  * @c: UBIFS file-system description object
475  *
476  * This function is called by garbage collection to determine if commit should
477  * be run. If commit state is @COMMIT_BACKGROUND, which means that the journal
478  * is full enough to start commit, this function returns true. It is not
479  * absolutely necessary to commit yet, but it feels like this should be better
480  * then to keep doing GC. This function returns %1 if GC has to initiate commit
481  * and %0 if not.
482  */
483 int ubifs_gc_should_commit(struct ubifs_info *c)
484 {
485         int ret = 0;
486 
487         spin_lock(&c->cs_lock);
488         if (c->cmt_state == COMMIT_BACKGROUND) {
489                 dbg_cmt("commit required now");
490                 c->cmt_state = COMMIT_REQUIRED;
491         } else
492                 dbg_cmt("commit not requested");
493         if (c->cmt_state == COMMIT_REQUIRED)
494                 ret = 1;
495         spin_unlock(&c->cs_lock);
496         return ret;
497 }
498 
499 /*
500  * Everything below is related to debugging.
501  */
502 
503 /**
504  * struct idx_node - hold index nodes during index tree traversal.
505  * @list: list
506  * @iip: index in parent (slot number of this indexing node in the parent
507  *       indexing node)
508  * @upper_key: all keys in this indexing node have to be less or equivalent to
509  *             this key
510  * @idx: index node (8-byte aligned because all node structures must be 8-byte
511  *       aligned)
512  */
513 struct idx_node {
514         struct list_head list;
515         int iip;
516         union ubifs_key upper_key;
517         struct ubifs_idx_node idx __attribute__((aligned(8)));
518 };
519 
520 /**
521  * dbg_old_index_check_init - get information for the next old index check.
522  * @c: UBIFS file-system description object
523  * @zroot: root of the index
524  *
525  * This function records information about the index that will be needed for the
526  * next old index check i.e. 'dbg_check_old_index()'.
527  *
528  * This function returns %0 on success and a negative error code on failure.
529  */
530 int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot)
531 {
532         struct ubifs_idx_node *idx;
533         int lnum, offs, len, err = 0;
534         struct ubifs_debug_info *d = c->dbg;
535 
536         d->old_zroot = *zroot;
537         lnum = d->old_zroot.lnum;
538         offs = d->old_zroot.offs;
539         len = d->old_zroot.len;
540 
541         idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
542         if (!idx)
543                 return -ENOMEM;
544 
545         err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
546         if (err)
547                 goto out;
548 
549         d->old_zroot_level = le16_to_cpu(idx->level);
550         d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);
551 out:
552         kfree(idx);
553         return err;
554 }
555 
556 /**
557  * dbg_check_old_index - check the old copy of the index.
558  * @c: UBIFS file-system description object
559  * @zroot: root of the new index
560  *
561  * In order to be able to recover from an unclean unmount, a complete copy of
562  * the index must exist on flash. This is the "old" index. The commit process
563  * must write the "new" index to flash without overwriting or destroying any
564  * part of the old index. This function is run at commit end in order to check
565  * that the old index does indeed exist completely intact.
566  *
567  * This function returns %0 on success and a negative error code on failure.
568  */
569 int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
570 {
571         int lnum, offs, len, err = 0, uninitialized_var(last_level), child_cnt;
572         int first = 1, iip;
573         struct ubifs_debug_info *d = c->dbg;
574         union ubifs_key uninitialized_var(lower_key), upper_key, l_key, u_key;
575         unsigned long long uninitialized_var(last_sqnum);
576         struct ubifs_idx_node *idx;
577         struct list_head list;
578         struct idx_node *i;
579         size_t sz;
580 
581         if (!dbg_is_chk_index(c))
582                 return 0;
583 
584         INIT_LIST_HEAD(&list);
585 
586         sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) -
587              UBIFS_IDX_NODE_SZ;
588 
589         /* Start at the old zroot */
590         lnum = d->old_zroot.lnum;
591         offs = d->old_zroot.offs;
592         len = d->old_zroot.len;
593         iip = 0;
594 
595         /*
596          * Traverse the index tree preorder depth-first i.e. do a node and then
597          * its subtrees from left to right.
598          */
599         while (1) {
600                 struct ubifs_branch *br;
601 
602                 /* Get the next index node */
603                 i = kmalloc(sz, GFP_NOFS);
604                 if (!i) {
605                         err = -ENOMEM;
606                         goto out_free;
607                 }
608                 i->iip = iip;
609                 /* Keep the index nodes on our path in a linked list */
610                 list_add_tail(&i->list, &list);
611                 /* Read the index node */
612                 idx = &i->idx;
613                 err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
614                 if (err)
615                         goto out_free;
616                 /* Validate index node */
617                 child_cnt = le16_to_cpu(idx->child_cnt);
618                 if (child_cnt < 1 || child_cnt > c->fanout) {
619                         err = 1;
620                         goto out_dump;
621                 }
622                 if (first) {
623                         first = 0;
624                         /* Check root level and sqnum */
625                         if (le16_to_cpu(idx->level) != d->old_zroot_level) {
626                                 err = 2;
627                                 goto out_dump;
628                         }
629                         if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {
630                                 err = 3;
631                                 goto out_dump;
632                         }
633                         /* Set last values as though root had a parent */
634                         last_level = le16_to_cpu(idx->level) + 1;
635                         last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1;
636                         key_read(c, ubifs_idx_key(c, idx), &lower_key);
637                         highest_ino_key(c, &upper_key, INUM_WATERMARK);
638                 }
639                 key_copy(c, &upper_key, &i->upper_key);
640                 if (le16_to_cpu(idx->level) != last_level - 1) {
641                         err = 3;
642                         goto out_dump;
643                 }
644                 /*
645                  * The index is always written bottom up hence a child's sqnum
646                  * is always less than the parents.
647                  */
648                 if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) {
649                         err = 4;
650                         goto out_dump;
651                 }
652                 /* Check key range */
653                 key_read(c, ubifs_idx_key(c, idx), &l_key);
654                 br = ubifs_idx_branch(c, idx, child_cnt - 1);
655                 key_read(c, &br->key, &u_key);
656                 if (keys_cmp(c, &lower_key, &l_key) > 0) {
657                         err = 5;
658                         goto out_dump;
659                 }
660                 if (keys_cmp(c, &upper_key, &u_key) < 0) {
661                         err = 6;
662                         goto out_dump;
663                 }
664                 if (keys_cmp(c, &upper_key, &u_key) == 0)
665                         if (!is_hash_key(c, &u_key)) {
666                                 err = 7;
667                                 goto out_dump;
668                         }
669                 /* Go to next index node */
670                 if (le16_to_cpu(idx->level) == 0) {
671                         /* At the bottom, so go up until can go right */
672                         while (1) {
673                                 /* Drop the bottom of the list */
674                                 list_del(&i->list);
675                                 kfree(i);
676                                 /* No more list means we are done */
677                                 if (list_empty(&list))
678                                         goto out;
679                                 /* Look at the new bottom */
680                                 i = list_entry(list.prev, struct idx_node,
681                                                list);
682                                 idx = &i->idx;
683                                 /* Can we go right */
684                                 if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
685                                         iip = iip + 1;
686                                         break;
687                                 } else
688                                         /* Nope, so go up again */
689                                         iip = i->iip;
690                         }
691                 } else
692                         /* Go down left */
693                         iip = 0;
694                 /*
695                  * We have the parent in 'idx' and now we set up for reading the
696                  * child pointed to by slot 'iip'.
697                  */
698                 last_level = le16_to_cpu(idx->level);
699                 last_sqnum = le64_to_cpu(idx->ch.sqnum);
700                 br = ubifs_idx_branch(c, idx, iip);
701                 lnum = le32_to_cpu(br->lnum);
702                 offs = le32_to_cpu(br->offs);
703                 len = le32_to_cpu(br->len);
704                 key_read(c, &br->key, &lower_key);
705                 if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
706                         br = ubifs_idx_branch(c, idx, iip + 1);
707                         key_read(c, &br->key, &upper_key);
708                 } else
709                         key_copy(c, &i->upper_key, &upper_key);
710         }
711 out:
712         err = dbg_old_index_check_init(c, zroot);
713         if (err)
714                 goto out_free;
715 
716         return 0;
717 
718 out_dump:
719         ubifs_err("dumping index node (iip=%d)", i->iip);
720         ubifs_dump_node(c, idx);
721         list_del(&i->list);
722         kfree(i);
723         if (!list_empty(&list)) {
724                 i = list_entry(list.prev, struct idx_node, list);
725                 ubifs_err("dumping parent index node");
726                 ubifs_dump_node(c, &i->idx);
727         }
728 out_free:
729         while (!list_empty(&list)) {
730                 i = list_entry(list.next, struct idx_node, list);
731                 list_del(&i->list);
732                 kfree(i);
733         }
734         ubifs_err("failed, error %d", err);
735         if (err > 0)
736                 err = -EINVAL;
737         return err;
738 }
739 

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