2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
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.
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
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
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
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
32 #ifdef CONFIG_UBIFS_FS_DEBUG
33 static int dbg_check_bud_bytes(struct ubifs_info *c);
35 #define dbg_check_bud_bytes(c) 0
39 * ubifs_search_bud - search bud LEB.
40 * @c: UBIFS file-system description object
41 * @lnum: logical eraseblock number to search
43 * This function searches bud LEB @lnum. Returns bud description object in case
44 * of success and %NULL if there is no bud with this LEB number.
46 struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum)
49 struct ubifs_bud *bud;
51 spin_lock(&c->buds_lock);
54 bud = rb_entry(p, struct ubifs_bud, rb);
57 else if (lnum > bud->lnum)
60 spin_unlock(&c->buds_lock);
64 spin_unlock(&c->buds_lock);
69 * ubifs_get_wbuf - get the wbuf associated with a LEB, if there is one.
70 * @c: UBIFS file-system description object
71 * @lnum: logical eraseblock number to search
73 * This functions returns the wbuf for @lnum or %NULL if there is not one.
75 struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum)
78 struct ubifs_bud *bud;
84 spin_lock(&c->buds_lock);
87 bud = rb_entry(p, struct ubifs_bud, rb);
90 else if (lnum > bud->lnum)
94 spin_unlock(&c->buds_lock);
95 return &c->jheads[jhead].wbuf;
98 spin_unlock(&c->buds_lock);
103 * next_log_lnum - switch to the next log LEB.
104 * @c: UBIFS file-system description object
105 * @lnum: current log LEB
107 static inline int next_log_lnum(const struct ubifs_info *c, int lnum)
110 if (lnum > c->log_last)
111 lnum = UBIFS_LOG_LNUM;
117 * empty_log_bytes - calculate amount of empty space in the log.
118 * @c: UBIFS file-system description object
120 static inline long long empty_log_bytes(const struct ubifs_info *c)
124 h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs;
125 t = (long long)c->ltail_lnum * c->leb_size;
128 return c->log_bytes - h + t;
134 * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list.
135 * @c: UBIFS file-system description object
136 * @bud: the bud to add
138 void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud)
140 struct rb_node **p, *parent = NULL;
142 struct ubifs_jhead *jhead;
144 spin_lock(&c->buds_lock);
145 p = &c->buds.rb_node;
148 b = rb_entry(parent, struct ubifs_bud, rb);
149 ubifs_assert(bud->lnum != b->lnum);
150 if (bud->lnum < b->lnum)
156 rb_link_node(&bud->rb, parent, p);
157 rb_insert_color(&bud->rb, &c->buds);
159 jhead = &c->jheads[bud->jhead];
160 list_add_tail(&bud->list, &jhead->buds_list);
162 ubifs_assert(c->replaying && c->ro_mount);
165 * Note, although this is a new bud, we anyway account this space now,
166 * before any data has been written to it, because this is about to
167 * guarantee fixed mount time, and this bud will anyway be read and
170 c->bud_bytes += c->leb_size - bud->start;
172 dbg_log("LEB %d:%d, jhead %s, bud_bytes %lld", bud->lnum,
173 bud->start, dbg_jhead(bud->jhead), c->bud_bytes);
174 spin_unlock(&c->buds_lock);
178 * ubifs_add_bud_to_log - add a new bud to the log.
179 * @c: UBIFS file-system description object
180 * @jhead: journal head the bud belongs to
181 * @lnum: LEB number of the bud
182 * @offs: starting offset of the bud
184 * This function writes reference node for the new bud LEB @lnum it to the log,
185 * and adds it to the buds tress. It also makes sure that log size does not
186 * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success,
187 * %-EAGAIN if commit is required, and a negative error codes in case of
190 int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)
193 struct ubifs_bud *bud;
194 struct ubifs_ref_node *ref;
196 bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS);
199 ref = kzalloc(c->ref_node_alsz, GFP_NOFS);
205 mutex_lock(&c->log_mutex);
206 ubifs_assert(!c->ro_media && !c->ro_mount);
212 /* Make sure we have enough space in the log */
213 if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
214 dbg_log("not enough log space - %lld, required %d",
215 empty_log_bytes(c), c->min_log_bytes);
216 ubifs_commit_required(c);
222 * Make sure the amount of space in buds will not exceed the
223 * 'c->max_bud_bytes' limit, because we want to guarantee mount time
226 * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
227 * because we are holding @c->log_mutex. All @c->bud_bytes take place
228 * when both @c->log_mutex and @c->bud_bytes are locked.
230 if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
231 dbg_log("bud bytes %lld (%lld max), require commit",
232 c->bud_bytes, c->max_bud_bytes);
233 ubifs_commit_required(c);
239 * If the journal is full enough - start background commit. Note, it is
240 * OK to read 'c->cmt_state' without spinlock because integer reads
241 * are atomic in the kernel.
243 if (c->bud_bytes >= c->bg_bud_bytes &&
244 c->cmt_state == COMMIT_RESTING) {
245 dbg_log("bud bytes %lld (%lld max), initiate BG commit",
246 c->bud_bytes, c->max_bud_bytes);
247 ubifs_request_bg_commit(c);
254 ref->ch.node_type = UBIFS_REF_NODE;
255 ref->lnum = cpu_to_le32(bud->lnum);
256 ref->offs = cpu_to_le32(bud->start);
257 ref->jhead = cpu_to_le32(jhead);
259 if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
260 c->lhead_lnum = next_log_lnum(c, c->lhead_lnum);
264 if (c->lhead_offs == 0) {
265 /* Must ensure next log LEB has been unmapped */
266 err = ubifs_leb_unmap(c, c->lhead_lnum);
271 if (bud->start == 0) {
273 * Before writing the LEB reference which refers an empty LEB
274 * to the log, we have to make sure it is mapped, because
275 * otherwise we'd risk to refer an LEB with garbage in case of
276 * an unclean reboot, because the target LEB might have been
277 * unmapped, but not yet physically erased.
279 err = ubi_leb_map(c->ubi, bud->lnum, UBI_SHORTTERM);
284 dbg_log("write ref LEB %d:%d",
285 c->lhead_lnum, c->lhead_offs);
286 err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
287 c->lhead_offs, UBI_SHORTTERM);
291 c->lhead_offs += c->ref_node_alsz;
293 ubifs_add_bud(c, bud);
295 mutex_unlock(&c->log_mutex);
301 ubifs_ro_mode(c, err);
302 mutex_unlock(&c->log_mutex);
309 * remove_buds - remove used buds.
310 * @c: UBIFS file-system description object
312 * This function removes use buds from the buds tree. It does not remove the
313 * buds which are pointed to by journal heads.
315 static void remove_buds(struct ubifs_info *c)
319 ubifs_assert(list_empty(&c->old_buds));
320 c->cmt_bud_bytes = 0;
321 spin_lock(&c->buds_lock);
322 p = rb_first(&c->buds);
324 struct rb_node *p1 = p;
325 struct ubifs_bud *bud;
326 struct ubifs_wbuf *wbuf;
329 bud = rb_entry(p1, struct ubifs_bud, rb);
330 wbuf = &c->jheads[bud->jhead].wbuf;
332 if (wbuf->lnum == bud->lnum) {
334 * Do not remove buds which are pointed to by journal
335 * heads (non-closed buds).
337 c->cmt_bud_bytes += wbuf->offs - bud->start;
338 dbg_log("preserve %d:%d, jhead %s, bud bytes %d, "
339 "cmt_bud_bytes %lld", bud->lnum, bud->start,
340 dbg_jhead(bud->jhead), wbuf->offs - bud->start,
342 bud->start = wbuf->offs;
344 c->cmt_bud_bytes += c->leb_size - bud->start;
345 dbg_log("remove %d:%d, jhead %s, bud bytes %d, "
346 "cmt_bud_bytes %lld", bud->lnum, bud->start,
347 dbg_jhead(bud->jhead), c->leb_size - bud->start,
349 rb_erase(p1, &c->buds);
351 * If the commit does not finish, the recovery will need
352 * to replay the journal, in which case the old buds
353 * must be unchanged. Do not release them until post
354 * commit i.e. do not allow them to be garbage
357 list_move(&bud->list, &c->old_buds);
360 spin_unlock(&c->buds_lock);
364 * ubifs_log_start_commit - start commit.
365 * @c: UBIFS file-system description object
366 * @ltail_lnum: return new log tail LEB number
368 * The commit operation starts with writing "commit start" node to the log and
369 * reference nodes for all journal heads which will define new journal after
370 * the commit has been finished. The commit start and reference nodes are
371 * written in one go to the nearest empty log LEB (hence, when commit is
372 * finished UBIFS may safely unmap all the previous log LEBs). This function
373 * returns zero in case of success and a negative error code in case of
376 int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
379 struct ubifs_cs_node *cs;
380 struct ubifs_ref_node *ref;
381 int err, i, max_len, len;
383 err = dbg_check_bud_bytes(c);
387 max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
388 max_len = ALIGN(max_len, c->min_io_size);
389 buf = cs = kmalloc(max_len, GFP_NOFS);
393 cs->ch.node_type = UBIFS_CS_NODE;
394 cs->cmt_no = cpu_to_le64(c->cmt_no);
395 ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
398 * Note, we do not lock 'c->log_mutex' because this is the commit start
399 * phase and we are exclusively using the log. And we do not lock
400 * write-buffer because nobody can write to the file-system at this
404 len = UBIFS_CS_NODE_SZ;
405 for (i = 0; i < c->jhead_cnt; i++) {
406 int lnum = c->jheads[i].wbuf.lnum;
407 int offs = c->jheads[i].wbuf.offs;
409 if (lnum == -1 || offs == c->leb_size)
412 dbg_log("add ref to LEB %d:%d for jhead %s",
413 lnum, offs, dbg_jhead(i));
415 ref->ch.node_type = UBIFS_REF_NODE;
416 ref->lnum = cpu_to_le32(lnum);
417 ref->offs = cpu_to_le32(offs);
418 ref->jhead = cpu_to_le32(i);
420 ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
421 len += UBIFS_REF_NODE_SZ;
424 ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
426 /* Switch to the next log LEB */
428 c->lhead_lnum = next_log_lnum(c, c->lhead_lnum);
432 if (c->lhead_offs == 0) {
433 /* Must ensure next LEB has been unmapped */
434 err = ubifs_leb_unmap(c, c->lhead_lnum);
439 len = ALIGN(len, c->min_io_size);
440 dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
441 err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len, UBI_SHORTTERM);
445 *ltail_lnum = c->lhead_lnum;
447 c->lhead_offs += len;
448 if (c->lhead_offs == c->leb_size) {
449 c->lhead_lnum = next_log_lnum(c, c->lhead_lnum);
456 * We have started the commit and now users may use the rest of the log
459 c->min_log_bytes = 0;
467 * ubifs_log_end_commit - end commit.
468 * @c: UBIFS file-system description object
469 * @ltail_lnum: new log tail LEB number
471 * This function is called on when the commit operation was finished. It
472 * moves log tail to new position and unmaps LEBs which contain obsolete data.
473 * Returns zero in case of success and a negative error code in case of
476 int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
481 * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS
482 * writes during commit. Its only short "commit" start phase when
483 * writers are blocked.
485 mutex_lock(&c->log_mutex);
487 dbg_log("old tail was LEB %d:0, new tail is LEB %d:0",
488 c->ltail_lnum, ltail_lnum);
490 c->ltail_lnum = ltail_lnum;
492 * The commit is finished and from now on it must be guaranteed that
493 * there is always enough space for the next commit.
495 c->min_log_bytes = c->leb_size;
497 spin_lock(&c->buds_lock);
498 c->bud_bytes -= c->cmt_bud_bytes;
499 spin_unlock(&c->buds_lock);
501 err = dbg_check_bud_bytes(c);
503 mutex_unlock(&c->log_mutex);
508 * ubifs_log_post_commit - things to do after commit is completed.
509 * @c: UBIFS file-system description object
510 * @old_ltail_lnum: old log tail LEB number
512 * Release buds only after commit is completed, because they must be unchanged
513 * if recovery is needed.
515 * Unmap log LEBs only after commit is completed, because they may be needed for
518 * This function returns %0 on success and a negative error code on failure.
520 int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum)
524 while (!list_empty(&c->old_buds)) {
525 struct ubifs_bud *bud;
527 bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
528 err = ubifs_return_leb(c, bud->lnum);
531 list_del(&bud->list);
534 mutex_lock(&c->log_mutex);
535 for (lnum = old_ltail_lnum; lnum != c->ltail_lnum;
536 lnum = next_log_lnum(c, lnum)) {
537 dbg_log("unmap log LEB %d", lnum);
538 err = ubifs_leb_unmap(c, lnum);
543 mutex_unlock(&c->log_mutex);
548 * struct done_ref - references that have been done.
558 * done_already - determine if a reference has been done already.
559 * @done_tree: rb-tree to store references that have been done
560 * @lnum: LEB number of reference
562 * This function returns %1 if the reference has been done, %0 if not, otherwise
563 * a negative error code is returned.
565 static int done_already(struct rb_root *done_tree, int lnum)
567 struct rb_node **p = &done_tree->rb_node, *parent = NULL;
572 dr = rb_entry(parent, struct done_ref, rb);
575 else if (lnum > dr->lnum)
581 dr = kzalloc(sizeof(struct done_ref), GFP_NOFS);
587 rb_link_node(&dr->rb, parent, p);
588 rb_insert_color(&dr->rb, done_tree);
594 * destroy_done_tree - destroy the done tree.
595 * @done_tree: done tree to destroy
597 static void destroy_done_tree(struct rb_root *done_tree)
599 struct rb_node *this = done_tree->rb_node;
604 this = this->rb_left;
606 } else if (this->rb_right) {
607 this = this->rb_right;
610 dr = rb_entry(this, struct done_ref, rb);
611 this = rb_parent(this);
613 if (this->rb_left == &dr->rb)
614 this->rb_left = NULL;
616 this->rb_right = NULL;
623 * add_node - add a node to the consolidated log.
624 * @c: UBIFS file-system description object
625 * @buf: buffer to which to add
626 * @lnum: LEB number to which to write is passed and returned here
627 * @offs: offset to where to write is passed and returned here
630 * This function returns %0 on success and a negative error code on failure.
632 static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
635 struct ubifs_ch *ch = node;
636 int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
639 int sz = ALIGN(*offs, c->min_io_size), err;
641 ubifs_pad(c, buf + *offs, sz - *offs);
642 err = ubifs_leb_change(c, *lnum, buf, sz, UBI_SHORTTERM);
645 *lnum = next_log_lnum(c, *lnum);
648 memcpy(buf + *offs, node, len);
649 *offs += ALIGN(len, 8);
654 * ubifs_consolidate_log - consolidate the log.
655 * @c: UBIFS file-system description object
657 * Repeated failed commits could cause the log to be full, but at least 1 LEB is
658 * needed for commit. This function rewrites the reference nodes in the log
659 * omitting duplicates, and failed CS nodes, and leaving no gaps.
661 * This function returns %0 on success and a negative error code on failure.
663 int ubifs_consolidate_log(struct ubifs_info *c)
665 struct ubifs_scan_leb *sleb;
666 struct ubifs_scan_node *snod;
667 struct rb_root done_tree = RB_ROOT;
668 int lnum, err, first = 1, write_lnum, offs = 0;
671 dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
673 buf = vmalloc(c->leb_size);
676 lnum = c->ltail_lnum;
679 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
684 list_for_each_entry(snod, &sleb->nodes, list) {
685 switch (snod->type) {
686 case UBIFS_REF_NODE: {
687 struct ubifs_ref_node *ref = snod->node;
688 int ref_lnum = le32_to_cpu(ref->lnum);
690 err = done_already(&done_tree, ref_lnum);
694 err = add_node(c, buf, &write_lnum,
704 err = add_node(c, buf, &write_lnum, &offs,
712 ubifs_scan_destroy(sleb);
713 if (lnum == c->lhead_lnum)
715 lnum = next_log_lnum(c, lnum);
718 int sz = ALIGN(offs, c->min_io_size);
720 ubifs_pad(c, buf + offs, sz - offs);
721 err = ubifs_leb_change(c, write_lnum, buf, sz, UBI_SHORTTERM);
724 offs = ALIGN(offs, c->min_io_size);
726 destroy_done_tree(&done_tree);
728 if (write_lnum == c->lhead_lnum) {
729 ubifs_err("log is too full");
732 /* Unmap remaining LEBs */
735 lnum = next_log_lnum(c, lnum);
736 err = ubifs_leb_unmap(c, lnum);
739 } while (lnum != c->lhead_lnum);
740 c->lhead_lnum = write_lnum;
741 c->lhead_offs = offs;
742 dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
746 ubifs_scan_destroy(sleb);
748 destroy_done_tree(&done_tree);
753 #ifdef CONFIG_UBIFS_FS_DEBUG
756 * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
757 * @c: UBIFS file-system description object
759 * This function makes sure the amount of flash space used by closed buds
760 * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
763 static int dbg_check_bud_bytes(struct ubifs_info *c)
766 struct ubifs_bud *bud;
767 long long bud_bytes = 0;
769 if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
772 spin_lock(&c->buds_lock);
773 for (i = 0; i < c->jhead_cnt; i++)
774 list_for_each_entry(bud, &c->jheads[i].buds_list, list)
775 bud_bytes += c->leb_size - bud->start;
777 if (c->bud_bytes != bud_bytes) {
778 ubifs_err("bad bud_bytes %lld, calculated %lld",
779 c->bud_bytes, bud_bytes);
782 spin_unlock(&c->buds_lock);
787 #endif /* CONFIG_UBIFS_FS_DEBUG */