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: Artem Bityutskiy (Битюцкий Артём)
8  *          Adrian Hunter
9  */
10 
11 /*
12  * This file is a part of UBIFS journal implementation and contains various
13  * functions which manipulate the log. The log is a fixed area on the flash
14  * which does not contain any data but refers to buds. The log is a part of the
15  * journal.
16  */
17 
18 #include "ubifs.h"
19 
20 static int dbg_check_bud_bytes(struct ubifs_info *c);
21 
22 /**
23  * ubifs_search_bud - search bud LEB.
24  * @c: UBIFS file-system description object
25  * @lnum: logical eraseblock number to search
26  *
27  * This function searches bud LEB @lnum. Returns bud description object in case
28  * of success and %NULL if there is no bud with this LEB number.
29  */
ubifs_search_bud(struct ubifs_info * c,int lnum)30 struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum)
31 {
32 	struct rb_node *p;
33 	struct ubifs_bud *bud;
34 
35 	spin_lock(&c->buds_lock);
36 	p = c->buds.rb_node;
37 	while (p) {
38 		bud = rb_entry(p, struct ubifs_bud, rb);
39 		if (lnum < bud->lnum)
40 			p = p->rb_left;
41 		else if (lnum > bud->lnum)
42 			p = p->rb_right;
43 		else {
44 			spin_unlock(&c->buds_lock);
45 			return bud;
46 		}
47 	}
48 	spin_unlock(&c->buds_lock);
49 	return NULL;
50 }
51 
52 /**
53  * ubifs_get_wbuf - get the wbuf associated with a LEB, if there is one.
54  * @c: UBIFS file-system description object
55  * @lnum: logical eraseblock number to search
56  *
57  * This functions returns the wbuf for @lnum or %NULL if there is not one.
58  */
ubifs_get_wbuf(struct ubifs_info * c,int lnum)59 struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum)
60 {
61 	struct rb_node *p;
62 	struct ubifs_bud *bud;
63 	int jhead;
64 
65 	if (!c->jheads)
66 		return NULL;
67 
68 	spin_lock(&c->buds_lock);
69 	p = c->buds.rb_node;
70 	while (p) {
71 		bud = rb_entry(p, struct ubifs_bud, rb);
72 		if (lnum < bud->lnum)
73 			p = p->rb_left;
74 		else if (lnum > bud->lnum)
75 			p = p->rb_right;
76 		else {
77 			jhead = bud->jhead;
78 			spin_unlock(&c->buds_lock);
79 			return &c->jheads[jhead].wbuf;
80 		}
81 	}
82 	spin_unlock(&c->buds_lock);
83 	return NULL;
84 }
85 
86 /**
87  * empty_log_bytes - calculate amount of empty space in the log.
88  * @c: UBIFS file-system description object
89  */
empty_log_bytes(const struct ubifs_info * c)90 static inline long long empty_log_bytes(const struct ubifs_info *c)
91 {
92 	long long h, t;
93 
94 	h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs;
95 	t = (long long)c->ltail_lnum * c->leb_size;
96 
97 	if (h > t)
98 		return c->log_bytes - h + t;
99 	else if (h != t)
100 		return t - h;
101 	else if (c->lhead_lnum != c->ltail_lnum)
102 		return 0;
103 	else
104 		return c->log_bytes;
105 }
106 
107 /**
108  * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list.
109  * @c: UBIFS file-system description object
110  * @bud: the bud to add
111  */
ubifs_add_bud(struct ubifs_info * c,struct ubifs_bud * bud)112 void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud)
113 {
114 	struct rb_node **p, *parent = NULL;
115 	struct ubifs_bud *b;
116 	struct ubifs_jhead *jhead;
117 
118 	spin_lock(&c->buds_lock);
119 	p = &c->buds.rb_node;
120 	while (*p) {
121 		parent = *p;
122 		b = rb_entry(parent, struct ubifs_bud, rb);
123 		ubifs_assert(c, bud->lnum != b->lnum);
124 		if (bud->lnum < b->lnum)
125 			p = &(*p)->rb_left;
126 		else
127 			p = &(*p)->rb_right;
128 	}
129 
130 	rb_link_node(&bud->rb, parent, p);
131 	rb_insert_color(&bud->rb, &c->buds);
132 	if (c->jheads) {
133 		jhead = &c->jheads[bud->jhead];
134 		list_add_tail(&bud->list, &jhead->buds_list);
135 	} else
136 		ubifs_assert(c, c->replaying && c->ro_mount);
137 
138 	/*
139 	 * Note, although this is a new bud, we anyway account this space now,
140 	 * before any data has been written to it, because this is about to
141 	 * guarantee fixed mount time, and this bud will anyway be read and
142 	 * scanned.
143 	 */
144 	c->bud_bytes += c->leb_size - bud->start;
145 
146 	dbg_log("LEB %d:%d, jhead %s, bud_bytes %lld", bud->lnum,
147 		bud->start, dbg_jhead(bud->jhead), c->bud_bytes);
148 	spin_unlock(&c->buds_lock);
149 }
150 
151 /**
152  * ubifs_add_bud_to_log - add a new bud to the log.
153  * @c: UBIFS file-system description object
154  * @jhead: journal head the bud belongs to
155  * @lnum: LEB number of the bud
156  * @offs: starting offset of the bud
157  *
158  * This function writes a reference node for the new bud LEB @lnum to the log,
159  * and adds it to the buds trees. It also makes sure that log size does not
160  * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success,
161  * %-EAGAIN if commit is required, and a negative error code in case of
162  * failure.
163  */
ubifs_add_bud_to_log(struct ubifs_info * c,int jhead,int lnum,int offs)164 int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)
165 {
166 	int err;
167 	struct ubifs_bud *bud;
168 	struct ubifs_ref_node *ref;
169 
170 	bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS);
171 	if (!bud)
172 		return -ENOMEM;
173 	ref = kzalloc(c->ref_node_alsz, GFP_NOFS);
174 	if (!ref) {
175 		kfree(bud);
176 		return -ENOMEM;
177 	}
178 
179 	mutex_lock(&c->log_mutex);
180 	ubifs_assert(c, !c->ro_media && !c->ro_mount);
181 	if (c->ro_error) {
182 		err = -EROFS;
183 		goto out_unlock;
184 	}
185 
186 	/* Make sure we have enough space in the log */
187 	if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
188 		dbg_log("not enough log space - %lld, required %d",
189 			empty_log_bytes(c), c->min_log_bytes);
190 		ubifs_commit_required(c);
191 		err = -EAGAIN;
192 		goto out_unlock;
193 	}
194 
195 	/*
196 	 * Make sure the amount of space in buds will not exceed the
197 	 * 'c->max_bud_bytes' limit, because we want to guarantee mount time
198 	 * limits.
199 	 *
200 	 * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
201 	 * because we are holding @c->log_mutex. All @c->bud_bytes take place
202 	 * when both @c->log_mutex and @c->bud_bytes are locked.
203 	 */
204 	if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
205 		dbg_log("bud bytes %lld (%lld max), require commit",
206 			c->bud_bytes, c->max_bud_bytes);
207 		ubifs_commit_required(c);
208 		err = -EAGAIN;
209 		goto out_unlock;
210 	}
211 
212 	/*
213 	 * If the journal is full enough - start background commit. Note, it is
214 	 * OK to read 'c->cmt_state' without spinlock because integer reads
215 	 * are atomic in the kernel.
216 	 */
217 	if (c->bud_bytes >= c->bg_bud_bytes &&
218 	    c->cmt_state == COMMIT_RESTING) {
219 		dbg_log("bud bytes %lld (%lld max), initiate BG commit",
220 			c->bud_bytes, c->max_bud_bytes);
221 		ubifs_request_bg_commit(c);
222 	}
223 
224 	bud->lnum = lnum;
225 	bud->start = offs;
226 	bud->jhead = jhead;
227 	bud->log_hash = NULL;
228 
229 	ref->ch.node_type = UBIFS_REF_NODE;
230 	ref->lnum = cpu_to_le32(bud->lnum);
231 	ref->offs = cpu_to_le32(bud->start);
232 	ref->jhead = cpu_to_le32(jhead);
233 
234 	if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
235 		c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
236 		ubifs_assert(c, c->lhead_lnum != c->ltail_lnum);
237 		c->lhead_offs = 0;
238 	}
239 
240 	if (c->lhead_offs == 0) {
241 		/* Must ensure next log LEB has been unmapped */
242 		err = ubifs_leb_unmap(c, c->lhead_lnum);
243 		if (err)
244 			goto out_unlock;
245 	}
246 
247 	if (bud->start == 0) {
248 		/*
249 		 * Before writing the LEB reference which refers an empty LEB
250 		 * to the log, we have to make sure it is mapped, because
251 		 * otherwise we'd risk to refer an LEB with garbage in case of
252 		 * an unclean reboot, because the target LEB might have been
253 		 * unmapped, but not yet physically erased.
254 		 */
255 		err = ubifs_leb_map(c, bud->lnum);
256 		if (err)
257 			goto out_unlock;
258 	}
259 
260 	dbg_log("write ref LEB %d:%d",
261 		c->lhead_lnum, c->lhead_offs);
262 	err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
263 			       c->lhead_offs);
264 	if (err)
265 		goto out_unlock;
266 
267 	err = ubifs_shash_update(c, c->log_hash, ref, UBIFS_REF_NODE_SZ);
268 	if (err)
269 		goto out_unlock;
270 
271 	err = ubifs_shash_copy_state(c, c->log_hash, c->jheads[jhead].log_hash);
272 	if (err)
273 		goto out_unlock;
274 
275 	c->lhead_offs += c->ref_node_alsz;
276 
277 	ubifs_add_bud(c, bud);
278 
279 	mutex_unlock(&c->log_mutex);
280 	kfree(ref);
281 	return 0;
282 
283 out_unlock:
284 	mutex_unlock(&c->log_mutex);
285 	kfree(ref);
286 	kfree(bud);
287 	return err;
288 }
289 
290 /**
291  * remove_buds - remove used buds.
292  * @c: UBIFS file-system description object
293  *
294  * This function removes use buds from the buds tree. It does not remove the
295  * buds which are pointed to by journal heads.
296  */
remove_buds(struct ubifs_info * c)297 static void remove_buds(struct ubifs_info *c)
298 {
299 	struct rb_node *p;
300 
301 	ubifs_assert(c, list_empty(&c->old_buds));
302 	c->cmt_bud_bytes = 0;
303 	spin_lock(&c->buds_lock);
304 	p = rb_first(&c->buds);
305 	while (p) {
306 		struct rb_node *p1 = p;
307 		struct ubifs_bud *bud;
308 		struct ubifs_wbuf *wbuf;
309 
310 		p = rb_next(p);
311 		bud = rb_entry(p1, struct ubifs_bud, rb);
312 		wbuf = &c->jheads[bud->jhead].wbuf;
313 
314 		if (wbuf->lnum == bud->lnum) {
315 			/*
316 			 * Do not remove buds which are pointed to by journal
317 			 * heads (non-closed buds).
318 			 */
319 			c->cmt_bud_bytes += wbuf->offs - bud->start;
320 			dbg_log("preserve %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
321 				bud->lnum, bud->start, dbg_jhead(bud->jhead),
322 				wbuf->offs - bud->start, c->cmt_bud_bytes);
323 			bud->start = wbuf->offs;
324 		} else {
325 			c->cmt_bud_bytes += c->leb_size - bud->start;
326 			dbg_log("remove %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
327 				bud->lnum, bud->start, dbg_jhead(bud->jhead),
328 				c->leb_size - bud->start, c->cmt_bud_bytes);
329 			rb_erase(p1, &c->buds);
330 			/*
331 			 * If the commit does not finish, the recovery will need
332 			 * to replay the journal, in which case the old buds
333 			 * must be unchanged. Do not release them until post
334 			 * commit i.e. do not allow them to be garbage
335 			 * collected.
336 			 */
337 			list_move(&bud->list, &c->old_buds);
338 		}
339 	}
340 	spin_unlock(&c->buds_lock);
341 }
342 
343 /**
344  * ubifs_log_start_commit - start commit.
345  * @c: UBIFS file-system description object
346  * @ltail_lnum: return new log tail LEB number
347  *
348  * The commit operation starts with writing "commit start" node to the log and
349  * reference nodes for all journal heads which will define new journal after
350  * the commit has been finished. The commit start and reference nodes are
351  * written in one go to the nearest empty log LEB (hence, when commit is
352  * finished UBIFS may safely unmap all the previous log LEBs). This function
353  * returns zero in case of success and a negative error code in case of
354  * failure.
355  */
ubifs_log_start_commit(struct ubifs_info * c,int * ltail_lnum)356 int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
357 {
358 	void *buf;
359 	struct ubifs_cs_node *cs;
360 	struct ubifs_ref_node *ref;
361 	int err, i, max_len, len;
362 
363 	err = dbg_check_bud_bytes(c);
364 	if (err)
365 		return err;
366 
367 	max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
368 	max_len = ALIGN(max_len, c->min_io_size);
369 	buf = cs = kmalloc(max_len, GFP_NOFS);
370 	if (!buf)
371 		return -ENOMEM;
372 
373 	cs->ch.node_type = UBIFS_CS_NODE;
374 	cs->cmt_no = cpu_to_le64(c->cmt_no);
375 	ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
376 
377 	err = ubifs_shash_init(c, c->log_hash);
378 	if (err)
379 		goto out;
380 
381 	err = ubifs_shash_update(c, c->log_hash, cs, UBIFS_CS_NODE_SZ);
382 	if (err < 0)
383 		goto out;
384 
385 	/*
386 	 * Note, we do not lock 'c->log_mutex' because this is the commit start
387 	 * phase and we are exclusively using the log. And we do not lock
388 	 * write-buffer because nobody can write to the file-system at this
389 	 * phase.
390 	 */
391 
392 	len = UBIFS_CS_NODE_SZ;
393 	for (i = 0; i < c->jhead_cnt; i++) {
394 		int lnum = c->jheads[i].wbuf.lnum;
395 		int offs = c->jheads[i].wbuf.offs;
396 
397 		if (lnum == -1 || offs == c->leb_size)
398 			continue;
399 
400 		dbg_log("add ref to LEB %d:%d for jhead %s",
401 			lnum, offs, dbg_jhead(i));
402 		ref = buf + len;
403 		ref->ch.node_type = UBIFS_REF_NODE;
404 		ref->lnum = cpu_to_le32(lnum);
405 		ref->offs = cpu_to_le32(offs);
406 		ref->jhead = cpu_to_le32(i);
407 
408 		ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
409 		len += UBIFS_REF_NODE_SZ;
410 
411 		err = ubifs_shash_update(c, c->log_hash, ref,
412 					 UBIFS_REF_NODE_SZ);
413 		if (err)
414 			goto out;
415 		ubifs_shash_copy_state(c, c->log_hash, c->jheads[i].log_hash);
416 	}
417 
418 	ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
419 
420 	/* Switch to the next log LEB */
421 	if (c->lhead_offs) {
422 		c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
423 		ubifs_assert(c, c->lhead_lnum != c->ltail_lnum);
424 		c->lhead_offs = 0;
425 	}
426 
427 	/* Must ensure next LEB has been unmapped */
428 	err = ubifs_leb_unmap(c, c->lhead_lnum);
429 	if (err)
430 		goto out;
431 
432 	len = ALIGN(len, c->min_io_size);
433 	dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
434 	err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len);
435 	if (err)
436 		goto out;
437 
438 	*ltail_lnum = c->lhead_lnum;
439 
440 	c->lhead_offs += len;
441 	ubifs_assert(c, c->lhead_offs < c->leb_size);
442 
443 	remove_buds(c);
444 
445 	/*
446 	 * We have started the commit and now users may use the rest of the log
447 	 * for new writes.
448 	 */
449 	c->min_log_bytes = 0;
450 
451 out:
452 	kfree(buf);
453 	return err;
454 }
455 
456 /**
457  * ubifs_log_end_commit - end commit.
458  * @c: UBIFS file-system description object
459  * @ltail_lnum: new log tail LEB number
460  *
461  * This function is called on when the commit operation was finished. It
462  * moves log tail to new position and updates the master node so that it stores
463  * the new log tail LEB number. Returns zero in case of success and a negative
464  * error code in case of failure.
465  */
ubifs_log_end_commit(struct ubifs_info * c,int ltail_lnum)466 int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
467 {
468 	int err;
469 
470 	/*
471 	 * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS
472 	 * writes during commit. Its only short "commit" start phase when
473 	 * writers are blocked.
474 	 */
475 	mutex_lock(&c->log_mutex);
476 
477 	dbg_log("old tail was LEB %d:0, new tail is LEB %d:0",
478 		c->ltail_lnum, ltail_lnum);
479 
480 	c->ltail_lnum = ltail_lnum;
481 	/*
482 	 * The commit is finished and from now on it must be guaranteed that
483 	 * there is always enough space for the next commit.
484 	 */
485 	c->min_log_bytes = c->leb_size;
486 
487 	spin_lock(&c->buds_lock);
488 	c->bud_bytes -= c->cmt_bud_bytes;
489 	spin_unlock(&c->buds_lock);
490 
491 	err = dbg_check_bud_bytes(c);
492 	if (err)
493 		goto out;
494 
495 	err = ubifs_write_master(c);
496 
497 out:
498 	mutex_unlock(&c->log_mutex);
499 	return err;
500 }
501 
502 /**
503  * ubifs_log_post_commit - things to do after commit is completed.
504  * @c: UBIFS file-system description object
505  * @old_ltail_lnum: old log tail LEB number
506  *
507  * Release buds only after commit is completed, because they must be unchanged
508  * if recovery is needed.
509  *
510  * Unmap log LEBs only after commit is completed, because they may be needed for
511  * recovery.
512  *
513  * This function returns %0 on success and a negative error code on failure.
514  */
ubifs_log_post_commit(struct ubifs_info * c,int old_ltail_lnum)515 int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum)
516 {
517 	int lnum, err = 0;
518 
519 	while (!list_empty(&c->old_buds)) {
520 		struct ubifs_bud *bud;
521 
522 		bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
523 		err = ubifs_return_leb(c, bud->lnum);
524 		if (err)
525 			return err;
526 		list_del(&bud->list);
527 		kfree(bud->log_hash);
528 		kfree(bud);
529 	}
530 	mutex_lock(&c->log_mutex);
531 	for (lnum = old_ltail_lnum; lnum != c->ltail_lnum;
532 	     lnum = ubifs_next_log_lnum(c, lnum)) {
533 		dbg_log("unmap log LEB %d", lnum);
534 		err = ubifs_leb_unmap(c, lnum);
535 		if (err)
536 			goto out;
537 	}
538 out:
539 	mutex_unlock(&c->log_mutex);
540 	return err;
541 }
542 
543 /**
544  * struct done_ref - references that have been done.
545  * @rb: rb-tree node
546  * @lnum: LEB number
547  */
548 struct done_ref {
549 	struct rb_node rb;
550 	int lnum;
551 };
552 
553 /**
554  * done_already - determine if a reference has been done already.
555  * @done_tree: rb-tree to store references that have been done
556  * @lnum: LEB number of reference
557  *
558  * This function returns %1 if the reference has been done, %0 if not, otherwise
559  * a negative error code is returned.
560  */
done_already(struct rb_root * done_tree,int lnum)561 static int done_already(struct rb_root *done_tree, int lnum)
562 {
563 	struct rb_node **p = &done_tree->rb_node, *parent = NULL;
564 	struct done_ref *dr;
565 
566 	while (*p) {
567 		parent = *p;
568 		dr = rb_entry(parent, struct done_ref, rb);
569 		if (lnum < dr->lnum)
570 			p = &(*p)->rb_left;
571 		else if (lnum > dr->lnum)
572 			p = &(*p)->rb_right;
573 		else
574 			return 1;
575 	}
576 
577 	dr = kzalloc(sizeof(struct done_ref), GFP_NOFS);
578 	if (!dr)
579 		return -ENOMEM;
580 
581 	dr->lnum = lnum;
582 
583 	rb_link_node(&dr->rb, parent, p);
584 	rb_insert_color(&dr->rb, done_tree);
585 
586 	return 0;
587 }
588 
589 /**
590  * destroy_done_tree - destroy the done tree.
591  * @done_tree: done tree to destroy
592  */
destroy_done_tree(struct rb_root * done_tree)593 static void destroy_done_tree(struct rb_root *done_tree)
594 {
595 	struct done_ref *dr, *n;
596 
597 	rbtree_postorder_for_each_entry_safe(dr, n, done_tree, rb)
598 		kfree(dr);
599 }
600 
601 /**
602  * add_node - add a node to the consolidated log.
603  * @c: UBIFS file-system description object
604  * @buf: buffer to which to add
605  * @lnum: LEB number to which to write is passed and returned here
606  * @offs: offset to where to write is passed and returned here
607  * @node: node to add
608  *
609  * This function returns %0 on success and a negative error code on failure.
610  */
add_node(struct ubifs_info * c,void * buf,int * lnum,int * offs,void * node)611 static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
612 		    void *node)
613 {
614 	struct ubifs_ch *ch = node;
615 	int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
616 
617 	if (len > remains) {
618 		int sz = ALIGN(*offs, c->min_io_size), err;
619 
620 		ubifs_pad(c, buf + *offs, sz - *offs);
621 		err = ubifs_leb_change(c, *lnum, buf, sz);
622 		if (err)
623 			return err;
624 		*lnum = ubifs_next_log_lnum(c, *lnum);
625 		*offs = 0;
626 	}
627 	memcpy(buf + *offs, node, len);
628 	*offs += ALIGN(len, 8);
629 	return 0;
630 }
631 
632 /**
633  * ubifs_consolidate_log - consolidate the log.
634  * @c: UBIFS file-system description object
635  *
636  * Repeated failed commits could cause the log to be full, but at least 1 LEB is
637  * needed for commit. This function rewrites the reference nodes in the log
638  * omitting duplicates, and failed CS nodes, and leaving no gaps.
639  *
640  * This function returns %0 on success and a negative error code on failure.
641  */
ubifs_consolidate_log(struct ubifs_info * c)642 int ubifs_consolidate_log(struct ubifs_info *c)
643 {
644 	struct ubifs_scan_leb *sleb;
645 	struct ubifs_scan_node *snod;
646 	struct rb_root done_tree = RB_ROOT;
647 	int lnum, err, first = 1, write_lnum, offs = 0;
648 	void *buf;
649 
650 	dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
651 		  c->lhead_lnum);
652 	buf = vmalloc(c->leb_size);
653 	if (!buf)
654 		return -ENOMEM;
655 	lnum = c->ltail_lnum;
656 	write_lnum = lnum;
657 	while (1) {
658 		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
659 		if (IS_ERR(sleb)) {
660 			err = PTR_ERR(sleb);
661 			goto out_free;
662 		}
663 		list_for_each_entry(snod, &sleb->nodes, list) {
664 			switch (snod->type) {
665 			case UBIFS_REF_NODE: {
666 				struct ubifs_ref_node *ref = snod->node;
667 				int ref_lnum = le32_to_cpu(ref->lnum);
668 
669 				err = done_already(&done_tree, ref_lnum);
670 				if (err < 0)
671 					goto out_scan;
672 				if (err != 1) {
673 					err = add_node(c, buf, &write_lnum,
674 						       &offs, snod->node);
675 					if (err)
676 						goto out_scan;
677 				}
678 				break;
679 			}
680 			case UBIFS_CS_NODE:
681 				if (!first)
682 					break;
683 				err = add_node(c, buf, &write_lnum, &offs,
684 					       snod->node);
685 				if (err)
686 					goto out_scan;
687 				first = 0;
688 				break;
689 			}
690 		}
691 		ubifs_scan_destroy(sleb);
692 		if (lnum == c->lhead_lnum)
693 			break;
694 		lnum = ubifs_next_log_lnum(c, lnum);
695 	}
696 	if (offs) {
697 		int sz = ALIGN(offs, c->min_io_size);
698 
699 		ubifs_pad(c, buf + offs, sz - offs);
700 		err = ubifs_leb_change(c, write_lnum, buf, sz);
701 		if (err)
702 			goto out_free;
703 		offs = ALIGN(offs, c->min_io_size);
704 	}
705 	destroy_done_tree(&done_tree);
706 	vfree(buf);
707 	if (write_lnum == c->lhead_lnum) {
708 		ubifs_err(c, "log is too full");
709 		return -EINVAL;
710 	}
711 	/* Unmap remaining LEBs */
712 	lnum = write_lnum;
713 	do {
714 		lnum = ubifs_next_log_lnum(c, lnum);
715 		err = ubifs_leb_unmap(c, lnum);
716 		if (err)
717 			return err;
718 	} while (lnum != c->lhead_lnum);
719 	c->lhead_lnum = write_lnum;
720 	c->lhead_offs = offs;
721 	dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
722 	return 0;
723 
724 out_scan:
725 	ubifs_scan_destroy(sleb);
726 out_free:
727 	destroy_done_tree(&done_tree);
728 	vfree(buf);
729 	return err;
730 }
731 
732 /**
733  * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
734  * @c: UBIFS file-system description object
735  *
736  * This function makes sure the amount of flash space used by closed buds
737  * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
738  * case of failure.
739  */
dbg_check_bud_bytes(struct ubifs_info * c)740 static int dbg_check_bud_bytes(struct ubifs_info *c)
741 {
742 	int i, err = 0;
743 	struct ubifs_bud *bud;
744 	long long bud_bytes = 0;
745 
746 	if (!dbg_is_chk_gen(c))
747 		return 0;
748 
749 	spin_lock(&c->buds_lock);
750 	for (i = 0; i < c->jhead_cnt; i++)
751 		list_for_each_entry(bud, &c->jheads[i].buds_list, list)
752 			bud_bytes += c->leb_size - bud->start;
753 
754 	if (c->bud_bytes != bud_bytes) {
755 		ubifs_err(c, "bad bud_bytes %lld, calculated %lld",
756 			  c->bud_bytes, bud_bytes);
757 		err = -EINVAL;
758 	}
759 	spin_unlock(&c->buds_lock);
760 
761 	return err;
762 }
763