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  */
ubifs_search_bud(struct ubifs_info * c,int lnum)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  */
ubifs_get_wbuf(struct ubifs_info * c,int lnum)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  */
empty_log_bytes(const struct ubifs_info * c)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  */
ubifs_add_bud(struct ubifs_info * c,struct ubifs_bud * bud)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(c, 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, 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 a reference node for the new bud LEB @lnum to the log,
171  * and adds it to the buds trees. 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 code in case of
174  * failure.
175  */
ubifs_add_bud_to_log(struct ubifs_info * c,int jhead,int lnum,int offs)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, !c->ro_media && !c->ro_mount);
193 	if (c->ro_error) {
194 		err = -EROFS;
195 		goto out_unlock;
196 	}
197 
198 	/* Make sure we have enough space in the log */
199 	if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
200 		dbg_log("not enough log space - %lld, required %d",
201 			empty_log_bytes(c), c->min_log_bytes);
202 		ubifs_commit_required(c);
203 		err = -EAGAIN;
204 		goto out_unlock;
205 	}
206 
207 	/*
208 	 * Make sure the amount of space in buds will not exceed the
209 	 * 'c->max_bud_bytes' limit, because we want to guarantee mount time
210 	 * limits.
211 	 *
212 	 * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
213 	 * because we are holding @c->log_mutex. All @c->bud_bytes take place
214 	 * when both @c->log_mutex and @c->bud_bytes are locked.
215 	 */
216 	if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
217 		dbg_log("bud bytes %lld (%lld max), require commit",
218 			c->bud_bytes, c->max_bud_bytes);
219 		ubifs_commit_required(c);
220 		err = -EAGAIN;
221 		goto out_unlock;
222 	}
223 
224 	/*
225 	 * If the journal is full enough - start background commit. Note, it is
226 	 * OK to read 'c->cmt_state' without spinlock because integer reads
227 	 * are atomic in the kernel.
228 	 */
229 	if (c->bud_bytes >= c->bg_bud_bytes &&
230 	    c->cmt_state == COMMIT_RESTING) {
231 		dbg_log("bud bytes %lld (%lld max), initiate BG commit",
232 			c->bud_bytes, c->max_bud_bytes);
233 		ubifs_request_bg_commit(c);
234 	}
235 
236 	bud->lnum = lnum;
237 	bud->start = offs;
238 	bud->jhead = jhead;
239 
240 	ref->ch.node_type = UBIFS_REF_NODE;
241 	ref->lnum = cpu_to_le32(bud->lnum);
242 	ref->offs = cpu_to_le32(bud->start);
243 	ref->jhead = cpu_to_le32(jhead);
244 
245 	if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
246 		c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
247 		ubifs_assert(c, c->lhead_lnum != c->ltail_lnum);
248 		c->lhead_offs = 0;
249 	}
250 
251 	if (c->lhead_offs == 0) {
252 		/* Must ensure next log LEB has been unmapped */
253 		err = ubifs_leb_unmap(c, c->lhead_lnum);
254 		if (err)
255 			goto out_unlock;
256 	}
257 
258 	if (bud->start == 0) {
259 		/*
260 		 * Before writing the LEB reference which refers an empty LEB
261 		 * to the log, we have to make sure it is mapped, because
262 		 * otherwise we'd risk to refer an LEB with garbage in case of
263 		 * an unclean reboot, because the target LEB might have been
264 		 * unmapped, but not yet physically erased.
265 		 */
266 		err = ubifs_leb_map(c, bud->lnum);
267 		if (err)
268 			goto out_unlock;
269 	}
270 
271 	dbg_log("write ref LEB %d:%d",
272 		c->lhead_lnum, c->lhead_offs);
273 	err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
274 			       c->lhead_offs);
275 	if (err)
276 		goto out_unlock;
277 
278 	c->lhead_offs += c->ref_node_alsz;
279 
280 	ubifs_add_bud(c, bud);
281 
282 	mutex_unlock(&c->log_mutex);
283 	kfree(ref);
284 	return 0;
285 
286 out_unlock:
287 	mutex_unlock(&c->log_mutex);
288 	kfree(ref);
289 	kfree(bud);
290 	return err;
291 }
292 
293 /**
294  * remove_buds - remove used buds.
295  * @c: UBIFS file-system description object
296  *
297  * This function removes use buds from the buds tree. It does not remove the
298  * buds which are pointed to by journal heads.
299  */
remove_buds(struct ubifs_info * c)300 static void remove_buds(struct ubifs_info *c)
301 {
302 	struct rb_node *p;
303 
304 	ubifs_assert(c, list_empty(&c->old_buds));
305 	c->cmt_bud_bytes = 0;
306 	spin_lock(&c->buds_lock);
307 	p = rb_first(&c->buds);
308 	while (p) {
309 		struct rb_node *p1 = p;
310 		struct ubifs_bud *bud;
311 		struct ubifs_wbuf *wbuf;
312 
313 		p = rb_next(p);
314 		bud = rb_entry(p1, struct ubifs_bud, rb);
315 		wbuf = &c->jheads[bud->jhead].wbuf;
316 
317 		if (wbuf->lnum == bud->lnum) {
318 			/*
319 			 * Do not remove buds which are pointed to by journal
320 			 * heads (non-closed buds).
321 			 */
322 			c->cmt_bud_bytes += wbuf->offs - bud->start;
323 			dbg_log("preserve %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
324 				bud->lnum, bud->start, dbg_jhead(bud->jhead),
325 				wbuf->offs - bud->start, c->cmt_bud_bytes);
326 			bud->start = wbuf->offs;
327 		} else {
328 			c->cmt_bud_bytes += c->leb_size - bud->start;
329 			dbg_log("remove %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
330 				bud->lnum, bud->start, dbg_jhead(bud->jhead),
331 				c->leb_size - bud->start, c->cmt_bud_bytes);
332 			rb_erase(p1, &c->buds);
333 			/*
334 			 * If the commit does not finish, the recovery will need
335 			 * to replay the journal, in which case the old buds
336 			 * must be unchanged. Do not release them until post
337 			 * commit i.e. do not allow them to be garbage
338 			 * collected.
339 			 */
340 			list_move(&bud->list, &c->old_buds);
341 		}
342 	}
343 	spin_unlock(&c->buds_lock);
344 }
345 
346 /**
347  * ubifs_log_start_commit - start commit.
348  * @c: UBIFS file-system description object
349  * @ltail_lnum: return new log tail LEB number
350  *
351  * The commit operation starts with writing "commit start" node to the log and
352  * reference nodes for all journal heads which will define new journal after
353  * the commit has been finished. The commit start and reference nodes are
354  * written in one go to the nearest empty log LEB (hence, when commit is
355  * finished UBIFS may safely unmap all the previous log LEBs). This function
356  * returns zero in case of success and a negative error code in case of
357  * failure.
358  */
ubifs_log_start_commit(struct ubifs_info * c,int * ltail_lnum)359 int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
360 {
361 	void *buf;
362 	struct ubifs_cs_node *cs;
363 	struct ubifs_ref_node *ref;
364 	int err, i, max_len, len;
365 
366 	err = dbg_check_bud_bytes(c);
367 	if (err)
368 		return err;
369 
370 	max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
371 	max_len = ALIGN(max_len, c->min_io_size);
372 	buf = cs = kmalloc(max_len, GFP_NOFS);
373 	if (!buf)
374 		return -ENOMEM;
375 
376 	cs->ch.node_type = UBIFS_CS_NODE;
377 	cs->cmt_no = cpu_to_le64(c->cmt_no);
378 	ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
379 
380 	/*
381 	 * Note, we do not lock 'c->log_mutex' because this is the commit start
382 	 * phase and we are exclusively using the log. And we do not lock
383 	 * write-buffer because nobody can write to the file-system at this
384 	 * phase.
385 	 */
386 
387 	len = UBIFS_CS_NODE_SZ;
388 	for (i = 0; i < c->jhead_cnt; i++) {
389 		int lnum = c->jheads[i].wbuf.lnum;
390 		int offs = c->jheads[i].wbuf.offs;
391 
392 		if (lnum == -1 || offs == c->leb_size)
393 			continue;
394 
395 		dbg_log("add ref to LEB %d:%d for jhead %s",
396 			lnum, offs, dbg_jhead(i));
397 		ref = buf + len;
398 		ref->ch.node_type = UBIFS_REF_NODE;
399 		ref->lnum = cpu_to_le32(lnum);
400 		ref->offs = cpu_to_le32(offs);
401 		ref->jhead = cpu_to_le32(i);
402 
403 		ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
404 		len += UBIFS_REF_NODE_SZ;
405 	}
406 
407 	ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
408 
409 	/* Switch to the next log LEB */
410 	if (c->lhead_offs) {
411 		c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
412 		ubifs_assert(c, c->lhead_lnum != c->ltail_lnum);
413 		c->lhead_offs = 0;
414 	}
415 
416 	/* Must ensure next LEB has been unmapped */
417 	err = ubifs_leb_unmap(c, c->lhead_lnum);
418 	if (err)
419 		goto out;
420 
421 	len = ALIGN(len, c->min_io_size);
422 	dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
423 	err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len);
424 	if (err)
425 		goto out;
426 
427 	*ltail_lnum = c->lhead_lnum;
428 
429 	c->lhead_offs += len;
430 	if (c->lhead_offs == c->leb_size) {
431 		c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
432 		c->lhead_offs = 0;
433 	}
434 
435 	remove_buds(c);
436 
437 	/*
438 	 * We have started the commit and now users may use the rest of the log
439 	 * for new writes.
440 	 */
441 	c->min_log_bytes = 0;
442 
443 out:
444 	kfree(buf);
445 	return err;
446 }
447 
448 /**
449  * ubifs_log_end_commit - end commit.
450  * @c: UBIFS file-system description object
451  * @ltail_lnum: new log tail LEB number
452  *
453  * This function is called on when the commit operation was finished. It
454  * moves log tail to new position and updates the master node so that it stores
455  * the new log tail LEB number. Returns zero in case of success and a negative
456  * error code in case of failure.
457  */
ubifs_log_end_commit(struct ubifs_info * c,int ltail_lnum)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  */
ubifs_log_post_commit(struct ubifs_info * c,int old_ltail_lnum)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  */
done_already(struct rb_root * done_tree,int lnum)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  */
destroy_done_tree(struct rb_root * done_tree)584 static void destroy_done_tree(struct rb_root *done_tree)
585 {
586 	struct done_ref *dr, *n;
587 
588 	rbtree_postorder_for_each_entry_safe(dr, n, done_tree, rb)
589 		kfree(dr);
590 }
591 
592 /**
593  * add_node - add a node to the consolidated log.
594  * @c: UBIFS file-system description object
595  * @buf: buffer to which to add
596  * @lnum: LEB number to which to write is passed and returned here
597  * @offs: offset to where to write is passed and returned here
598  * @node: node to add
599  *
600  * This function returns %0 on success and a negative error code on failure.
601  */
add_node(struct ubifs_info * c,void * buf,int * lnum,int * offs,void * node)602 static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
603 		    void *node)
604 {
605 	struct ubifs_ch *ch = node;
606 	int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
607 
608 	if (len > remains) {
609 		int sz = ALIGN(*offs, c->min_io_size), err;
610 
611 		ubifs_pad(c, buf + *offs, sz - *offs);
612 		err = ubifs_leb_change(c, *lnum, buf, sz);
613 		if (err)
614 			return err;
615 		*lnum = ubifs_next_log_lnum(c, *lnum);
616 		*offs = 0;
617 	}
618 	memcpy(buf + *offs, node, len);
619 	*offs += ALIGN(len, 8);
620 	return 0;
621 }
622 
623 /**
624  * ubifs_consolidate_log - consolidate the log.
625  * @c: UBIFS file-system description object
626  *
627  * Repeated failed commits could cause the log to be full, but at least 1 LEB is
628  * needed for commit. This function rewrites the reference nodes in the log
629  * omitting duplicates, and failed CS nodes, and leaving no gaps.
630  *
631  * This function returns %0 on success and a negative error code on failure.
632  */
ubifs_consolidate_log(struct ubifs_info * c)633 int ubifs_consolidate_log(struct ubifs_info *c)
634 {
635 	struct ubifs_scan_leb *sleb;
636 	struct ubifs_scan_node *snod;
637 	struct rb_root done_tree = RB_ROOT;
638 	int lnum, err, first = 1, write_lnum, offs = 0;
639 	void *buf;
640 
641 	dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
642 		  c->lhead_lnum);
643 	buf = vmalloc(c->leb_size);
644 	if (!buf)
645 		return -ENOMEM;
646 	lnum = c->ltail_lnum;
647 	write_lnum = lnum;
648 	while (1) {
649 		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
650 		if (IS_ERR(sleb)) {
651 			err = PTR_ERR(sleb);
652 			goto out_free;
653 		}
654 		list_for_each_entry(snod, &sleb->nodes, list) {
655 			switch (snod->type) {
656 			case UBIFS_REF_NODE: {
657 				struct ubifs_ref_node *ref = snod->node;
658 				int ref_lnum = le32_to_cpu(ref->lnum);
659 
660 				err = done_already(&done_tree, ref_lnum);
661 				if (err < 0)
662 					goto out_scan;
663 				if (err != 1) {
664 					err = add_node(c, buf, &write_lnum,
665 						       &offs, snod->node);
666 					if (err)
667 						goto out_scan;
668 				}
669 				break;
670 			}
671 			case UBIFS_CS_NODE:
672 				if (!first)
673 					break;
674 				err = add_node(c, buf, &write_lnum, &offs,
675 					       snod->node);
676 				if (err)
677 					goto out_scan;
678 				first = 0;
679 				break;
680 			}
681 		}
682 		ubifs_scan_destroy(sleb);
683 		if (lnum == c->lhead_lnum)
684 			break;
685 		lnum = ubifs_next_log_lnum(c, lnum);
686 	}
687 	if (offs) {
688 		int sz = ALIGN(offs, c->min_io_size);
689 
690 		ubifs_pad(c, buf + offs, sz - offs);
691 		err = ubifs_leb_change(c, write_lnum, buf, sz);
692 		if (err)
693 			goto out_free;
694 		offs = ALIGN(offs, c->min_io_size);
695 	}
696 	destroy_done_tree(&done_tree);
697 	vfree(buf);
698 	if (write_lnum == c->lhead_lnum) {
699 		ubifs_err(c, "log is too full");
700 		return -EINVAL;
701 	}
702 	/* Unmap remaining LEBs */
703 	lnum = write_lnum;
704 	do {
705 		lnum = ubifs_next_log_lnum(c, lnum);
706 		err = ubifs_leb_unmap(c, lnum);
707 		if (err)
708 			return err;
709 	} while (lnum != c->lhead_lnum);
710 	c->lhead_lnum = write_lnum;
711 	c->lhead_offs = offs;
712 	dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
713 	return 0;
714 
715 out_scan:
716 	ubifs_scan_destroy(sleb);
717 out_free:
718 	destroy_done_tree(&done_tree);
719 	vfree(buf);
720 	return err;
721 }
722 
723 /**
724  * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
725  * @c: UBIFS file-system description object
726  *
727  * This function makes sure the amount of flash space used by closed buds
728  * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
729  * case of failure.
730  */
dbg_check_bud_bytes(struct ubifs_info * c)731 static int dbg_check_bud_bytes(struct ubifs_info *c)
732 {
733 	int i, err = 0;
734 	struct ubifs_bud *bud;
735 	long long bud_bytes = 0;
736 
737 	if (!dbg_is_chk_gen(c))
738 		return 0;
739 
740 	spin_lock(&c->buds_lock);
741 	for (i = 0; i < c->jhead_cnt; i++)
742 		list_for_each_entry(bud, &c->jheads[i].buds_list, list)
743 			bud_bytes += c->leb_size - bud->start;
744 
745 	if (c->bud_bytes != bud_bytes) {
746 		ubifs_err(c, "bad bud_bytes %lld, calculated %lld",
747 			  c->bud_bytes, bud_bytes);
748 		err = -EINVAL;
749 	}
750 	spin_unlock(&c->buds_lock);
751 
752 	return err;
753 }
754