1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * This file is part of UBIFS.
4  *
5  * Copyright (C) 2006-2008 Nokia Corporation.
6  *
7  * Authors: Adrian Hunter
8  *          Artem Bityutskiy (Битюцкий Артём)
9  */
10 
11 /*
12  * This file implements functions that manage the running of the commit process.
13  * Each affected module has its own functions to accomplish their part in the
14  * commit and those functions are called here.
15  *
16  * The commit is the process whereby all updates to the index and LEB properties
17  * are written out together and the journal becomes empty. This keeps the
18  * file system consistent - at all times the state can be recreated by reading
19  * the index and LEB properties and then replaying the journal.
20  *
21  * The commit is split into two parts named "commit start" and "commit end".
22  * During commit start, the commit process has exclusive access to the journal
23  * by holding the commit semaphore down for writing. As few I/O operations as
24  * possible are performed during commit start, instead the nodes that are to be
25  * written are merely identified. During commit end, the commit semaphore is no
26  * longer held and the journal is again in operation, allowing users to continue
27  * to use the file system while the bulk of the commit I/O is performed. The
28  * purpose of this two-step approach is to prevent the commit from causing any
29  * latency blips. Note that in any case, the commit does not prevent lookups
30  * (as permitted by the TNC mutex), or access to VFS data structures e.g. page
31  * cache.
32  */
33 
34 #include <linux/freezer.h>
35 #include <linux/kthread.h>
36 #include <linux/slab.h>
37 #include "ubifs.h"
38 
39 /*
40  * nothing_to_commit - check if there is nothing to commit.
41  * @c: UBIFS file-system description object
42  *
43  * This is a helper function which checks if there is anything to commit. It is
44  * used as an optimization to avoid starting the commit if it is not really
45  * necessary. Indeed, the commit operation always assumes flash I/O (e.g.,
46  * writing the commit start node to the log), and it is better to avoid doing
47  * this unnecessarily. E.g., 'ubifs_sync_fs()' runs the commit, but if there is
48  * nothing to commit, it is more optimal to avoid any flash I/O.
49  *
50  * This function has to be called with @c->commit_sem locked for writing -
51  * this function does not take LPT/TNC locks because the @c->commit_sem
52  * guarantees that we have exclusive access to the TNC and LPT data structures.
53  *
54  * This function returns %1 if there is nothing to commit and %0 otherwise.
55  */
nothing_to_commit(struct ubifs_info * c)56 static int nothing_to_commit(struct ubifs_info *c)
57 {
58 	/*
59 	 * During mounting or remounting from R/O mode to R/W mode we may
60 	 * commit for various recovery-related reasons.
61 	 */
62 	if (c->mounting || c->remounting_rw)
63 		return 0;
64 
65 	/*
66 	 * If the root TNC node is dirty, we definitely have something to
67 	 * commit.
68 	 */
69 	if (c->zroot.znode && ubifs_zn_dirty(c->zroot.znode))
70 		return 0;
71 
72 	/*
73 	 * Even though the TNC is clean, the LPT tree may have dirty nodes. For
74 	 * example, this may happen if the budgeting subsystem invoked GC to
75 	 * make some free space, and the GC found an LEB with only dirty and
76 	 * free space. In this case GC would just change the lprops of this
77 	 * LEB (by turning all space into free space) and unmap it.
78 	 */
79 	if (c->nroot && test_bit(DIRTY_CNODE, &c->nroot->flags))
80 		return 0;
81 
82 	ubifs_assert(c, atomic_long_read(&c->dirty_zn_cnt) == 0);
83 	ubifs_assert(c, c->dirty_pn_cnt == 0);
84 	ubifs_assert(c, c->dirty_nn_cnt == 0);
85 
86 	return 1;
87 }
88 
89 /**
90  * do_commit - commit the journal.
91  * @c: UBIFS file-system description object
92  *
93  * This function implements UBIFS commit. It has to be called with commit lock
94  * locked. Returns zero in case of success and a negative error code in case of
95  * failure.
96  */
do_commit(struct ubifs_info * c)97 static int do_commit(struct ubifs_info *c)
98 {
99 	int err, new_ltail_lnum, old_ltail_lnum, i;
100 	struct ubifs_zbranch zroot;
101 	struct ubifs_lp_stats lst;
102 
103 	dbg_cmt("start");
104 	ubifs_assert(c, !c->ro_media && !c->ro_mount);
105 
106 	if (c->ro_error) {
107 		err = -EROFS;
108 		goto out_up;
109 	}
110 
111 	if (nothing_to_commit(c)) {
112 		up_write(&c->commit_sem);
113 		err = 0;
114 		goto out_cancel;
115 	}
116 
117 	/* Sync all write buffers (necessary for recovery) */
118 	for (i = 0; i < c->jhead_cnt; i++) {
119 		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
120 		if (err)
121 			goto out_up;
122 	}
123 
124 	c->cmt_no += 1;
125 	err = ubifs_gc_start_commit(c);
126 	if (err)
127 		goto out_up;
128 	err = dbg_check_lprops(c);
129 	if (err)
130 		goto out_up;
131 	err = ubifs_log_start_commit(c, &new_ltail_lnum);
132 	if (err)
133 		goto out_up;
134 	err = ubifs_tnc_start_commit(c, &zroot);
135 	if (err)
136 		goto out_up;
137 	err = ubifs_lpt_start_commit(c);
138 	if (err)
139 		goto out_up;
140 	err = ubifs_orphan_start_commit(c);
141 	if (err)
142 		goto out_up;
143 
144 	ubifs_get_lp_stats(c, &lst);
145 
146 	up_write(&c->commit_sem);
147 
148 	err = ubifs_tnc_end_commit(c);
149 	if (err)
150 		goto out;
151 	err = ubifs_lpt_end_commit(c);
152 	if (err)
153 		goto out;
154 	err = ubifs_orphan_end_commit(c);
155 	if (err)
156 		goto out;
157 	err = dbg_check_old_index(c, &zroot);
158 	if (err)
159 		goto out;
160 
161 	c->mst_node->cmt_no      = cpu_to_le64(c->cmt_no);
162 	c->mst_node->log_lnum    = cpu_to_le32(new_ltail_lnum);
163 	c->mst_node->root_lnum   = cpu_to_le32(zroot.lnum);
164 	c->mst_node->root_offs   = cpu_to_le32(zroot.offs);
165 	c->mst_node->root_len    = cpu_to_le32(zroot.len);
166 	c->mst_node->ihead_lnum  = cpu_to_le32(c->ihead_lnum);
167 	c->mst_node->ihead_offs  = cpu_to_le32(c->ihead_offs);
168 	c->mst_node->index_size  = cpu_to_le64(c->bi.old_idx_sz);
169 	c->mst_node->lpt_lnum    = cpu_to_le32(c->lpt_lnum);
170 	c->mst_node->lpt_offs    = cpu_to_le32(c->lpt_offs);
171 	c->mst_node->nhead_lnum  = cpu_to_le32(c->nhead_lnum);
172 	c->mst_node->nhead_offs  = cpu_to_le32(c->nhead_offs);
173 	c->mst_node->ltab_lnum   = cpu_to_le32(c->ltab_lnum);
174 	c->mst_node->ltab_offs   = cpu_to_le32(c->ltab_offs);
175 	c->mst_node->lsave_lnum  = cpu_to_le32(c->lsave_lnum);
176 	c->mst_node->lsave_offs  = cpu_to_le32(c->lsave_offs);
177 	c->mst_node->lscan_lnum  = cpu_to_le32(c->lscan_lnum);
178 	c->mst_node->empty_lebs  = cpu_to_le32(lst.empty_lebs);
179 	c->mst_node->idx_lebs    = cpu_to_le32(lst.idx_lebs);
180 	c->mst_node->total_free  = cpu_to_le64(lst.total_free);
181 	c->mst_node->total_dirty = cpu_to_le64(lst.total_dirty);
182 	c->mst_node->total_used  = cpu_to_le64(lst.total_used);
183 	c->mst_node->total_dead  = cpu_to_le64(lst.total_dead);
184 	c->mst_node->total_dark  = cpu_to_le64(lst.total_dark);
185 	if (c->no_orphs)
186 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
187 	else
188 		c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_NO_ORPHS);
189 
190 	old_ltail_lnum = c->ltail_lnum;
191 	err = ubifs_log_end_commit(c, new_ltail_lnum);
192 	if (err)
193 		goto out;
194 
195 	err = ubifs_log_post_commit(c, old_ltail_lnum);
196 	if (err)
197 		goto out;
198 	err = ubifs_gc_end_commit(c);
199 	if (err)
200 		goto out;
201 	err = ubifs_lpt_post_commit(c);
202 	if (err)
203 		goto out;
204 
205 out_cancel:
206 	spin_lock(&c->cs_lock);
207 	c->cmt_state = COMMIT_RESTING;
208 	wake_up(&c->cmt_wq);
209 	dbg_cmt("commit end");
210 	spin_unlock(&c->cs_lock);
211 	return 0;
212 
213 out_up:
214 	up_write(&c->commit_sem);
215 out:
216 	ubifs_err(c, "commit failed, error %d", err);
217 	spin_lock(&c->cs_lock);
218 	c->cmt_state = COMMIT_BROKEN;
219 	wake_up(&c->cmt_wq);
220 	spin_unlock(&c->cs_lock);
221 	ubifs_ro_mode(c, err);
222 	return err;
223 }
224 
225 /**
226  * run_bg_commit - run background commit if it is needed.
227  * @c: UBIFS file-system description object
228  *
229  * This function runs background commit if it is needed. Returns zero in case
230  * of success and a negative error code in case of failure.
231  */
run_bg_commit(struct ubifs_info * c)232 static int run_bg_commit(struct ubifs_info *c)
233 {
234 	spin_lock(&c->cs_lock);
235 	/*
236 	 * Run background commit only if background commit was requested or if
237 	 * commit is required.
238 	 */
239 	if (c->cmt_state != COMMIT_BACKGROUND &&
240 	    c->cmt_state != COMMIT_REQUIRED)
241 		goto out;
242 	spin_unlock(&c->cs_lock);
243 
244 	down_write(&c->commit_sem);
245 	spin_lock(&c->cs_lock);
246 	if (c->cmt_state == COMMIT_REQUIRED)
247 		c->cmt_state = COMMIT_RUNNING_REQUIRED;
248 	else if (c->cmt_state == COMMIT_BACKGROUND)
249 		c->cmt_state = COMMIT_RUNNING_BACKGROUND;
250 	else
251 		goto out_cmt_unlock;
252 	spin_unlock(&c->cs_lock);
253 
254 	return do_commit(c);
255 
256 out_cmt_unlock:
257 	up_write(&c->commit_sem);
258 out:
259 	spin_unlock(&c->cs_lock);
260 	return 0;
261 }
262 
263 /**
264  * ubifs_bg_thread - UBIFS background thread function.
265  * @info: points to the file-system description object
266  *
267  * This function implements various file-system background activities:
268  * o when a write-buffer timer expires it synchronizes the appropriate
269  *   write-buffer;
270  * o when the journal is about to be full, it starts in-advance commit.
271  *
272  * Note, other stuff like background garbage collection may be added here in
273  * future.
274  */
ubifs_bg_thread(void * info)275 int ubifs_bg_thread(void *info)
276 {
277 	int err;
278 	struct ubifs_info *c = info;
279 
280 	ubifs_msg(c, "background thread \"%s\" started, PID %d",
281 		  c->bgt_name, current->pid);
282 	set_freezable();
283 
284 	while (1) {
285 		if (kthread_should_stop())
286 			break;
287 
288 		if (try_to_freeze())
289 			continue;
290 
291 		set_current_state(TASK_INTERRUPTIBLE);
292 		/* Check if there is something to do */
293 		if (!c->need_bgt) {
294 			/*
295 			 * Nothing prevents us from going sleep now and
296 			 * be never woken up and block the task which
297 			 * could wait in 'kthread_stop()' forever.
298 			 */
299 			if (kthread_should_stop())
300 				break;
301 			schedule();
302 			continue;
303 		} else
304 			__set_current_state(TASK_RUNNING);
305 
306 		c->need_bgt = 0;
307 		err = ubifs_bg_wbufs_sync(c);
308 		if (err)
309 			ubifs_ro_mode(c, err);
310 
311 		run_bg_commit(c);
312 		cond_resched();
313 	}
314 
315 	ubifs_msg(c, "background thread \"%s\" stops", c->bgt_name);
316 	return 0;
317 }
318 
319 /**
320  * ubifs_commit_required - set commit state to "required".
321  * @c: UBIFS file-system description object
322  *
323  * This function is called if a commit is required but cannot be done from the
324  * calling function, so it is just flagged instead.
325  */
ubifs_commit_required(struct ubifs_info * c)326 void ubifs_commit_required(struct ubifs_info *c)
327 {
328 	spin_lock(&c->cs_lock);
329 	switch (c->cmt_state) {
330 	case COMMIT_RESTING:
331 	case COMMIT_BACKGROUND:
332 		dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
333 			dbg_cstate(COMMIT_REQUIRED));
334 		c->cmt_state = COMMIT_REQUIRED;
335 		break;
336 	case COMMIT_RUNNING_BACKGROUND:
337 		dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
338 			dbg_cstate(COMMIT_RUNNING_REQUIRED));
339 		c->cmt_state = COMMIT_RUNNING_REQUIRED;
340 		break;
341 	case COMMIT_REQUIRED:
342 	case COMMIT_RUNNING_REQUIRED:
343 	case COMMIT_BROKEN:
344 		break;
345 	}
346 	spin_unlock(&c->cs_lock);
347 }
348 
349 /**
350  * ubifs_request_bg_commit - notify the background thread to do a commit.
351  * @c: UBIFS file-system description object
352  *
353  * This function is called if the journal is full enough to make a commit
354  * worthwhile, so background thread is kicked to start it.
355  */
ubifs_request_bg_commit(struct ubifs_info * c)356 void ubifs_request_bg_commit(struct ubifs_info *c)
357 {
358 	spin_lock(&c->cs_lock);
359 	if (c->cmt_state == COMMIT_RESTING) {
360 		dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
361 			dbg_cstate(COMMIT_BACKGROUND));
362 		c->cmt_state = COMMIT_BACKGROUND;
363 		spin_unlock(&c->cs_lock);
364 		ubifs_wake_up_bgt(c);
365 	} else
366 		spin_unlock(&c->cs_lock);
367 }
368 
369 /**
370  * wait_for_commit - wait for commit.
371  * @c: UBIFS file-system description object
372  *
373  * This function sleeps until the commit operation is no longer running.
374  */
wait_for_commit(struct ubifs_info * c)375 static int wait_for_commit(struct ubifs_info *c)
376 {
377 	dbg_cmt("pid %d goes sleep", current->pid);
378 
379 	/*
380 	 * The following sleeps if the condition is false, and will be woken
381 	 * when the commit ends. It is possible, although very unlikely, that we
382 	 * will wake up and see the subsequent commit running, rather than the
383 	 * one we were waiting for, and go back to sleep.  However, we will be
384 	 * woken again, so there is no danger of sleeping forever.
385 	 */
386 	wait_event(c->cmt_wq, c->cmt_state != COMMIT_RUNNING_BACKGROUND &&
387 			      c->cmt_state != COMMIT_RUNNING_REQUIRED);
388 	dbg_cmt("commit finished, pid %d woke up", current->pid);
389 	return 0;
390 }
391 
392 /**
393  * ubifs_run_commit - run or wait for commit.
394  * @c: UBIFS file-system description object
395  *
396  * This function runs commit and returns zero in case of success and a negative
397  * error code in case of failure.
398  */
ubifs_run_commit(struct ubifs_info * c)399 int ubifs_run_commit(struct ubifs_info *c)
400 {
401 	int err = 0;
402 
403 	spin_lock(&c->cs_lock);
404 	if (c->cmt_state == COMMIT_BROKEN) {
405 		err = -EROFS;
406 		goto out;
407 	}
408 
409 	if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
410 		/*
411 		 * We set the commit state to 'running required' to indicate
412 		 * that we want it to complete as quickly as possible.
413 		 */
414 		c->cmt_state = COMMIT_RUNNING_REQUIRED;
415 
416 	if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
417 		spin_unlock(&c->cs_lock);
418 		return wait_for_commit(c);
419 	}
420 	spin_unlock(&c->cs_lock);
421 
422 	/* Ok, the commit is indeed needed */
423 
424 	down_write(&c->commit_sem);
425 	spin_lock(&c->cs_lock);
426 	/*
427 	 * Since we unlocked 'c->cs_lock', the state may have changed, so
428 	 * re-check it.
429 	 */
430 	if (c->cmt_state == COMMIT_BROKEN) {
431 		err = -EROFS;
432 		goto out_cmt_unlock;
433 	}
434 
435 	if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
436 		c->cmt_state = COMMIT_RUNNING_REQUIRED;
437 
438 	if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
439 		up_write(&c->commit_sem);
440 		spin_unlock(&c->cs_lock);
441 		return wait_for_commit(c);
442 	}
443 	c->cmt_state = COMMIT_RUNNING_REQUIRED;
444 	spin_unlock(&c->cs_lock);
445 
446 	err = do_commit(c);
447 	return err;
448 
449 out_cmt_unlock:
450 	up_write(&c->commit_sem);
451 out:
452 	spin_unlock(&c->cs_lock);
453 	return err;
454 }
455 
456 /**
457  * ubifs_gc_should_commit - determine if it is time for GC to run commit.
458  * @c: UBIFS file-system description object
459  *
460  * This function is called by garbage collection to determine if commit should
461  * be run. If commit state is @COMMIT_BACKGROUND, which means that the journal
462  * is full enough to start commit, this function returns true. It is not
463  * absolutely necessary to commit yet, but it feels like this should be better
464  * then to keep doing GC. This function returns %1 if GC has to initiate commit
465  * and %0 if not.
466  */
ubifs_gc_should_commit(struct ubifs_info * c)467 int ubifs_gc_should_commit(struct ubifs_info *c)
468 {
469 	int ret = 0;
470 
471 	spin_lock(&c->cs_lock);
472 	if (c->cmt_state == COMMIT_BACKGROUND) {
473 		dbg_cmt("commit required now");
474 		c->cmt_state = COMMIT_REQUIRED;
475 	} else
476 		dbg_cmt("commit not requested");
477 	if (c->cmt_state == COMMIT_REQUIRED)
478 		ret = 1;
479 	spin_unlock(&c->cs_lock);
480 	return ret;
481 }
482 
483 /*
484  * Everything below is related to debugging.
485  */
486 
487 /**
488  * struct idx_node - hold index nodes during index tree traversal.
489  * @list: list
490  * @iip: index in parent (slot number of this indexing node in the parent
491  *       indexing node)
492  * @upper_key: all keys in this indexing node have to be less or equivalent to
493  *             this key
494  * @idx: index node (8-byte aligned because all node structures must be 8-byte
495  *       aligned)
496  */
497 struct idx_node {
498 	struct list_head list;
499 	int iip;
500 	union ubifs_key upper_key;
501 	struct ubifs_idx_node idx __aligned(8);
502 };
503 
504 /**
505  * dbg_old_index_check_init - get information for the next old index check.
506  * @c: UBIFS file-system description object
507  * @zroot: root of the index
508  *
509  * This function records information about the index that will be needed for the
510  * next old index check i.e. 'dbg_check_old_index()'.
511  *
512  * This function returns %0 on success and a negative error code on failure.
513  */
dbg_old_index_check_init(struct ubifs_info * c,struct ubifs_zbranch * zroot)514 int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot)
515 {
516 	struct ubifs_idx_node *idx;
517 	int lnum, offs, len, err = 0;
518 	struct ubifs_debug_info *d = c->dbg;
519 
520 	d->old_zroot = *zroot;
521 	lnum = d->old_zroot.lnum;
522 	offs = d->old_zroot.offs;
523 	len = d->old_zroot.len;
524 
525 	idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
526 	if (!idx)
527 		return -ENOMEM;
528 
529 	err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
530 	if (err)
531 		goto out;
532 
533 	d->old_zroot_level = le16_to_cpu(idx->level);
534 	d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);
535 out:
536 	kfree(idx);
537 	return err;
538 }
539 
540 /**
541  * dbg_check_old_index - check the old copy of the index.
542  * @c: UBIFS file-system description object
543  * @zroot: root of the new index
544  *
545  * In order to be able to recover from an unclean unmount, a complete copy of
546  * the index must exist on flash. This is the "old" index. The commit process
547  * must write the "new" index to flash without overwriting or destroying any
548  * part of the old index. This function is run at commit end in order to check
549  * that the old index does indeed exist completely intact.
550  *
551  * This function returns %0 on success and a negative error code on failure.
552  */
dbg_check_old_index(struct ubifs_info * c,struct ubifs_zbranch * zroot)553 int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
554 {
555 	int lnum, offs, len, err = 0, last_level, child_cnt;
556 	int first = 1, iip;
557 	struct ubifs_debug_info *d = c->dbg;
558 	union ubifs_key lower_key, upper_key, l_key, u_key;
559 	unsigned long long last_sqnum;
560 	struct ubifs_idx_node *idx;
561 	struct list_head list;
562 	struct idx_node *i;
563 	size_t sz;
564 
565 	if (!dbg_is_chk_index(c))
566 		return 0;
567 
568 	INIT_LIST_HEAD(&list);
569 
570 	sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) -
571 	     UBIFS_IDX_NODE_SZ;
572 
573 	/* Start at the old zroot */
574 	lnum = d->old_zroot.lnum;
575 	offs = d->old_zroot.offs;
576 	len = d->old_zroot.len;
577 	iip = 0;
578 
579 	/*
580 	 * Traverse the index tree preorder depth-first i.e. do a node and then
581 	 * its subtrees from left to right.
582 	 */
583 	while (1) {
584 		struct ubifs_branch *br;
585 
586 		/* Get the next index node */
587 		i = kmalloc(sz, GFP_NOFS);
588 		if (!i) {
589 			err = -ENOMEM;
590 			goto out_free;
591 		}
592 		i->iip = iip;
593 		/* Keep the index nodes on our path in a linked list */
594 		list_add_tail(&i->list, &list);
595 		/* Read the index node */
596 		idx = &i->idx;
597 		err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
598 		if (err)
599 			goto out_free;
600 		/* Validate index node */
601 		child_cnt = le16_to_cpu(idx->child_cnt);
602 		if (child_cnt < 1 || child_cnt > c->fanout) {
603 			err = 1;
604 			goto out_dump;
605 		}
606 		if (first) {
607 			first = 0;
608 			/* Check root level and sqnum */
609 			if (le16_to_cpu(idx->level) != d->old_zroot_level) {
610 				err = 2;
611 				goto out_dump;
612 			}
613 			if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {
614 				err = 3;
615 				goto out_dump;
616 			}
617 			/* Set last values as though root had a parent */
618 			last_level = le16_to_cpu(idx->level) + 1;
619 			last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1;
620 			key_read(c, ubifs_idx_key(c, idx), &lower_key);
621 			highest_ino_key(c, &upper_key, INUM_WATERMARK);
622 		}
623 		key_copy(c, &upper_key, &i->upper_key);
624 		if (le16_to_cpu(idx->level) != last_level - 1) {
625 			err = 3;
626 			goto out_dump;
627 		}
628 		/*
629 		 * The index is always written bottom up hence a child's sqnum
630 		 * is always less than the parents.
631 		 */
632 		if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) {
633 			err = 4;
634 			goto out_dump;
635 		}
636 		/* Check key range */
637 		key_read(c, ubifs_idx_key(c, idx), &l_key);
638 		br = ubifs_idx_branch(c, idx, child_cnt - 1);
639 		key_read(c, &br->key, &u_key);
640 		if (keys_cmp(c, &lower_key, &l_key) > 0) {
641 			err = 5;
642 			goto out_dump;
643 		}
644 		if (keys_cmp(c, &upper_key, &u_key) < 0) {
645 			err = 6;
646 			goto out_dump;
647 		}
648 		if (keys_cmp(c, &upper_key, &u_key) == 0)
649 			if (!is_hash_key(c, &u_key)) {
650 				err = 7;
651 				goto out_dump;
652 			}
653 		/* Go to next index node */
654 		if (le16_to_cpu(idx->level) == 0) {
655 			/* At the bottom, so go up until can go right */
656 			while (1) {
657 				/* Drop the bottom of the list */
658 				list_del(&i->list);
659 				kfree(i);
660 				/* No more list means we are done */
661 				if (list_empty(&list))
662 					goto out;
663 				/* Look at the new bottom */
664 				i = list_entry(list.prev, struct idx_node,
665 					       list);
666 				idx = &i->idx;
667 				/* Can we go right */
668 				if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
669 					iip = iip + 1;
670 					break;
671 				} else
672 					/* Nope, so go up again */
673 					iip = i->iip;
674 			}
675 		} else
676 			/* Go down left */
677 			iip = 0;
678 		/*
679 		 * We have the parent in 'idx' and now we set up for reading the
680 		 * child pointed to by slot 'iip'.
681 		 */
682 		last_level = le16_to_cpu(idx->level);
683 		last_sqnum = le64_to_cpu(idx->ch.sqnum);
684 		br = ubifs_idx_branch(c, idx, iip);
685 		lnum = le32_to_cpu(br->lnum);
686 		offs = le32_to_cpu(br->offs);
687 		len = le32_to_cpu(br->len);
688 		key_read(c, &br->key, &lower_key);
689 		if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
690 			br = ubifs_idx_branch(c, idx, iip + 1);
691 			key_read(c, &br->key, &upper_key);
692 		} else
693 			key_copy(c, &i->upper_key, &upper_key);
694 	}
695 out:
696 	err = dbg_old_index_check_init(c, zroot);
697 	if (err)
698 		goto out_free;
699 
700 	return 0;
701 
702 out_dump:
703 	ubifs_err(c, "dumping index node (iip=%d)", i->iip);
704 	ubifs_dump_node(c, idx, ubifs_idx_node_sz(c, c->fanout));
705 	list_del(&i->list);
706 	kfree(i);
707 	if (!list_empty(&list)) {
708 		i = list_entry(list.prev, struct idx_node, list);
709 		ubifs_err(c, "dumping parent index node");
710 		ubifs_dump_node(c, &i->idx, ubifs_idx_node_sz(c, c->fanout));
711 	}
712 out_free:
713 	while (!list_empty(&list)) {
714 		i = list_entry(list.next, struct idx_node, list);
715 		list_del(&i->list);
716 		kfree(i);
717 	}
718 	ubifs_err(c, "failed, error %d", err);
719 	if (err > 0)
720 		err = -EINVAL;
721 	return err;
722 }
723