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: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
24 * This file implements garbage collection. The procedure for garbage collection
25 * is different depending on whether a LEB as an index LEB (contains index
26 * nodes) or not. For non-index LEBs, garbage collection finds a LEB which
27 * contains a lot of dirty space (obsolete nodes), and copies the non-obsolete
28 * nodes to the journal, at which point the garbage-collected LEB is free to be
29 * reused. For index LEBs, garbage collection marks the non-obsolete index nodes
30 * dirty in the TNC, and after the next commit, the garbage-collected LEB is
31 * to be reused. Garbage collection will cause the number of dirty index nodes
32 * to grow, however sufficient space is reserved for the index to ensure the
33 * commit will never run out of space.
35 * Notes about dead watermark. At current UBIFS implementation we assume that
36 * LEBs which have less than @c->dead_wm bytes of free + dirty space are full
37 * and not worth garbage-collecting. The dead watermark is one min. I/O unit
38 * size, or min. UBIFS node size, depending on what is greater. Indeed, UBIFS
39 * Garbage Collector has to synchronize the GC head's write buffer before
40 * returning, so this is about wasting one min. I/O unit. However, UBIFS GC can
41 * actually reclaim even very small pieces of dirty space by garbage collecting
42 * enough dirty LEBs, but we do not bother doing this at this implementation.
44 * Notes about dark watermark. The results of GC work depends on how big are
45 * the UBIFS nodes GC deals with. Large nodes make GC waste more space. Indeed,
46 * if GC move data from LEB A to LEB B and nodes in LEB A are large, GC would
47 * have to waste large pieces of free space at the end of LEB B, because nodes
48 * from LEB A would not fit. And the worst situation is when all nodes are of
49 * maximum size. So dark watermark is the amount of free + dirty space in LEB
50 * which are guaranteed to be reclaimable. If LEB has less space, the GC might
51 * be unable to reclaim it. So, LEBs with free + dirty greater than dark
52 * watermark are "good" LEBs from GC's point of few. The other LEBs are not so
53 * good, and GC takes extra care when moving them.
56 #include <linux/slab.h>
57 #include <linux/pagemap.h>
58 #include <linux/list_sort.h>
62 * GC may need to move more than one LEB to make progress. The below constants
63 * define "soft" and "hard" limits on the number of LEBs the garbage collector
66 #define SOFT_LEBS_LIMIT 4
67 #define HARD_LEBS_LIMIT 32
70 * switch_gc_head - switch the garbage collection journal head.
71 * @c: UBIFS file-system description object
72 * @buf: buffer to write
73 * @len: length of the buffer to write
74 * @lnum: LEB number written is returned here
75 * @offs: offset written is returned here
77 * This function switch the GC head to the next LEB which is reserved in
78 * @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required,
79 * and other negative error code in case of failures.
81 static int switch_gc_head(struct ubifs_info *c)
83 int err, gc_lnum = c->gc_lnum;
84 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
86 ubifs_assert(gc_lnum != -1);
87 dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)",
88 wbuf->lnum, wbuf->offs + wbuf->used, gc_lnum,
89 c->leb_size - wbuf->offs - wbuf->used);
91 err = ubifs_wbuf_sync_nolock(wbuf);
96 * The GC write-buffer was synchronized, we may safely unmap
99 err = ubifs_leb_unmap(c, gc_lnum);
103 err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0);
108 err = ubifs_wbuf_seek_nolock(wbuf, gc_lnum, 0, UBI_LONGTERM);
113 * data_nodes_cmp - compare 2 data nodes.
114 * @priv: UBIFS file-system description object
115 * @a: first data node
116 * @a: second data node
118 * This function compares data nodes @a and @b. Returns %1 if @a has greater
119 * inode or block number, and %-1 otherwise.
121 int data_nodes_cmp(void *priv, struct list_head *a, struct list_head *b)
124 struct ubifs_info *c = priv;
125 struct ubifs_scan_node *sa, *sb;
131 sa = list_entry(a, struct ubifs_scan_node, list);
132 sb = list_entry(b, struct ubifs_scan_node, list);
134 ubifs_assert(key_type(c, &sa->key) == UBIFS_DATA_KEY);
135 ubifs_assert(key_type(c, &sb->key) == UBIFS_DATA_KEY);
136 ubifs_assert(sa->type == UBIFS_DATA_NODE);
137 ubifs_assert(sb->type == UBIFS_DATA_NODE);
139 inuma = key_inum(c, &sa->key);
140 inumb = key_inum(c, &sb->key);
142 if (inuma == inumb) {
143 unsigned int blka = key_block(c, &sa->key);
144 unsigned int blkb = key_block(c, &sb->key);
148 } else if (inuma <= inumb)
155 * nondata_nodes_cmp - compare 2 non-data nodes.
156 * @priv: UBIFS file-system description object
160 * This function compares nodes @a and @b. It makes sure that inode nodes go
161 * first and sorted by length in descending order. Directory entry nodes go
162 * after inode nodes and are sorted in ascending hash valuer order.
164 int nondata_nodes_cmp(void *priv, struct list_head *a, struct list_head *b)
167 struct ubifs_info *c = priv;
168 struct ubifs_scan_node *sa, *sb;
174 sa = list_entry(a, struct ubifs_scan_node, list);
175 sb = list_entry(b, struct ubifs_scan_node, list);
177 ubifs_assert(key_type(c, &sa->key) != UBIFS_DATA_KEY &&
178 key_type(c, &sb->key) != UBIFS_DATA_KEY);
179 ubifs_assert(sa->type != UBIFS_DATA_NODE &&
180 sb->type != UBIFS_DATA_NODE);
182 /* Inodes go before directory entries */
183 if (sa->type == UBIFS_INO_NODE) {
184 if (sb->type == UBIFS_INO_NODE)
185 return sb->len - sa->len;
188 if (sb->type == UBIFS_INO_NODE)
191 ubifs_assert(key_type(c, &sa->key) == UBIFS_DENT_KEY ||
192 key_type(c, &sa->key) == UBIFS_XENT_KEY);
193 ubifs_assert(key_type(c, &sb->key) == UBIFS_DENT_KEY ||
194 key_type(c, &sb->key) == UBIFS_XENT_KEY);
195 ubifs_assert(sa->type == UBIFS_DENT_NODE ||
196 sa->type == UBIFS_XENT_NODE);
197 ubifs_assert(sb->type == UBIFS_DENT_NODE ||
198 sb->type == UBIFS_XENT_NODE);
200 inuma = key_inum(c, &sa->key);
201 inumb = key_inum(c, &sb->key);
203 if (inuma == inumb) {
204 uint32_t hasha = key_hash(c, &sa->key);
205 uint32_t hashb = key_hash(c, &sb->key);
209 } else if (inuma <= inumb)
216 * sort_nodes - sort nodes for GC.
217 * @c: UBIFS file-system description object
218 * @sleb: describes nodes to sort and contains the result on exit
219 * @nondata: contains non-data nodes on exit
220 * @min: minimum node size is returned here
222 * This function sorts the list of inodes to garbage collect. First of all, it
223 * kills obsolete nodes and separates data and non-data nodes to the
224 * @sleb->nodes and @nondata lists correspondingly.
226 * Data nodes are then sorted in block number order - this is important for
227 * bulk-read; data nodes with lower inode number go before data nodes with
228 * higher inode number, and data nodes with lower block number go before data
229 * nodes with higher block number;
231 * Non-data nodes are sorted as follows.
232 * o First go inode nodes - they are sorted in descending length order.
233 * o Then go directory entry nodes - they are sorted in hash order, which
234 * should supposedly optimize 'readdir()'. Direntry nodes with lower parent
235 * inode number go before direntry nodes with higher parent inode number,
236 * and direntry nodes with lower name hash values go before direntry nodes
237 * with higher name hash values.
239 * This function returns zero in case of success and a negative error code in
242 static int sort_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
243 struct list_head *nondata, int *min)
245 struct ubifs_scan_node *snod, *tmp;
249 /* Separate data nodes and non-data nodes */
250 list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
253 ubifs_assert(snod->type == UBIFS_INO_NODE ||
254 snod->type == UBIFS_DATA_NODE ||
255 snod->type == UBIFS_DENT_NODE ||
256 snod->type == UBIFS_XENT_NODE ||
257 snod->type == UBIFS_TRUN_NODE);
259 if (snod->type != UBIFS_INO_NODE &&
260 snod->type != UBIFS_DATA_NODE &&
261 snod->type != UBIFS_DENT_NODE &&
262 snod->type != UBIFS_XENT_NODE) {
263 /* Probably truncation node, zap it */
264 list_del(&snod->list);
269 ubifs_assert(key_type(c, &snod->key) == UBIFS_DATA_KEY ||
270 key_type(c, &snod->key) == UBIFS_INO_KEY ||
271 key_type(c, &snod->key) == UBIFS_DENT_KEY ||
272 key_type(c, &snod->key) == UBIFS_XENT_KEY);
274 err = ubifs_tnc_has_node(c, &snod->key, 0, sleb->lnum,
280 /* The node is obsolete, remove it from the list */
281 list_del(&snod->list);
286 if (snod->len < *min)
289 if (key_type(c, &snod->key) != UBIFS_DATA_KEY)
290 list_move_tail(&snod->list, nondata);
293 /* Sort data and non-data nodes */
294 list_sort(c, &sleb->nodes, &data_nodes_cmp);
295 list_sort(c, nondata, &nondata_nodes_cmp);
300 * move_node - move a node.
301 * @c: UBIFS file-system description object
302 * @sleb: describes the LEB to move nodes from
303 * @snod: the mode to move
304 * @wbuf: write-buffer to move node to
306 * This function moves node @snod to @wbuf, changes TNC correspondingly, and
307 * destroys @snod. Returns zero in case of success and a negative error code in
310 static int move_node(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
311 struct ubifs_scan_node *snod, struct ubifs_wbuf *wbuf)
313 int err, new_lnum = wbuf->lnum, new_offs = wbuf->offs + wbuf->used;
316 err = ubifs_wbuf_write_nolock(wbuf, snod->node, snod->len);
320 err = ubifs_tnc_replace(c, &snod->key, sleb->lnum,
321 snod->offs, new_lnum, new_offs,
323 list_del(&snod->list);
329 * move_nodes - move nodes.
330 * @c: UBIFS file-system description object
331 * @sleb: describes the LEB to move nodes from
333 * This function moves valid nodes from data LEB described by @sleb to the GC
334 * journal head. This function returns zero in case of success, %-EAGAIN if
335 * commit is required, and other negative error codes in case of other
338 static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
342 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
344 if (wbuf->lnum == -1) {
346 * The GC journal head is not set, because it is the first GC
347 * invocation since mount.
349 err = switch_gc_head(c);
354 err = sort_nodes(c, sleb, &nondata, &min);
358 /* Write nodes to their new location. Use the first-fit strategy */
361 struct ubifs_scan_node *snod, *tmp;
363 /* Move data nodes */
364 list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
365 avail = c->leb_size - wbuf->offs - wbuf->used;
366 if (snod->len > avail)
368 * Do not skip data nodes in order to optimize
373 err = move_node(c, sleb, snod, wbuf);
378 /* Move non-data nodes */
379 list_for_each_entry_safe(snod, tmp, &nondata, list) {
380 avail = c->leb_size - wbuf->offs - wbuf->used;
384 if (snod->len > avail) {
386 * Keep going only if this is an inode with
387 * some data. Otherwise stop and switch the GC
388 * head. IOW, we assume that data-less inode
389 * nodes and direntry nodes are roughly of the
392 if (key_type(c, &snod->key) == UBIFS_DENT_KEY ||
393 snod->len == UBIFS_INO_NODE_SZ)
398 err = move_node(c, sleb, snod, wbuf);
403 if (list_empty(&sleb->nodes) && list_empty(&nondata))
407 * Waste the rest of the space in the LEB and switch to the
410 err = switch_gc_head(c);
418 list_splice_tail(&nondata, &sleb->nodes);
423 * gc_sync_wbufs - sync write-buffers for GC.
424 * @c: UBIFS file-system description object
426 * We must guarantee that obsoleting nodes are on flash. Unfortunately they may
427 * be in a write-buffer instead. That is, a node could be written to a
428 * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is
429 * erased before the write-buffer is sync'd and then there is an unclean
430 * unmount, then an existing node is lost. To avoid this, we sync all
433 * This function returns %0 on success or a negative error code on failure.
435 static int gc_sync_wbufs(struct ubifs_info *c)
439 for (i = 0; i < c->jhead_cnt; i++) {
442 err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
450 * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock.
451 * @c: UBIFS file-system description object
452 * @lp: describes the LEB to garbage collect
454 * This function garbage-collects an LEB and returns one of the @LEB_FREED,
455 * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is
456 * required, and other negative error codes in case of failures.
458 int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
460 struct ubifs_scan_leb *sleb;
461 struct ubifs_scan_node *snod;
462 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
463 int err = 0, lnum = lp->lnum;
465 ubifs_assert(c->gc_lnum != -1 || wbuf->offs + wbuf->used == 0 ||
467 ubifs_assert(c->gc_lnum != lnum);
468 ubifs_assert(wbuf->lnum != lnum);
471 * We scan the entire LEB even though we only really need to scan up to
472 * (c->leb_size - lp->free).
474 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
476 return PTR_ERR(sleb);
478 ubifs_assert(!list_empty(&sleb->nodes));
479 snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
481 if (snod->type == UBIFS_IDX_NODE) {
482 struct ubifs_gced_idx_leb *idx_gc;
484 dbg_gc("indexing LEB %d (free %d, dirty %d)",
485 lnum, lp->free, lp->dirty);
486 list_for_each_entry(snod, &sleb->nodes, list) {
487 struct ubifs_idx_node *idx = snod->node;
488 int level = le16_to_cpu(idx->level);
490 ubifs_assert(snod->type == UBIFS_IDX_NODE);
491 key_read(c, ubifs_idx_key(c, idx), &snod->key);
492 err = ubifs_dirty_idx_node(c, &snod->key, level, lnum,
498 idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
506 list_add(&idx_gc->list, &c->idx_gc);
509 * Don't release the LEB until after the next commit, because
510 * it may contain data which is needed for recovery. So
511 * although we freed this LEB, it will become usable only after
514 err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0,
520 dbg_gc("data LEB %d (free %d, dirty %d)",
521 lnum, lp->free, lp->dirty);
523 err = move_nodes(c, sleb);
527 err = gc_sync_wbufs(c);
531 err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);
535 /* Allow for races with TNC */
541 if (c->gc_lnum == -1) {
545 err = ubifs_wbuf_sync_nolock(wbuf);
549 err = ubifs_leb_unmap(c, lnum);
558 ubifs_scan_destroy(sleb);
562 /* We may have moved at least some nodes so allow for races with TNC */
571 * ubifs_garbage_collect - UBIFS garbage collector.
572 * @c: UBIFS file-system description object
573 * @anyway: do GC even if there are free LEBs
575 * This function does out-of-place garbage collection. The return codes are:
576 * o positive LEB number if the LEB has been freed and may be used;
577 * o %-EAGAIN if the caller has to run commit;
578 * o %-ENOSPC if GC failed to make any progress;
579 * o other negative error codes in case of other errors.
581 * Garbage collector writes data to the journal when GC'ing data LEBs, and just
582 * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point
583 * commit may be required. But commit cannot be run from inside GC, because the
584 * caller might be holding the commit lock, so %-EAGAIN is returned instead;
585 * And this error code means that the caller has to run commit, and re-run GC
586 * if there is still no free space.
588 * There are many reasons why this function may return %-EAGAIN:
589 * o the log is full and there is no space to write an LEB reference for
591 * o the journal is too large and exceeds size limitations;
592 * o GC moved indexing LEBs, but they can be used only after the commit;
593 * o the shrinker fails to find clean znodes to free and requests the commit;
596 * Note, if the file-system is close to be full, this function may return
597 * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of
598 * the function. E.g., this happens if the limits on the journal size are too
599 * tough and GC writes too much to the journal before an LEB is freed. This
600 * might also mean that the journal is too large, and the TNC becomes to big,
601 * so that the shrinker is constantly called, finds not clean znodes to free,
602 * and requests commit. Well, this may also happen if the journal is all right,
603 * but another kernel process consumes too much memory. Anyway, infinite
604 * %-EAGAIN may happen, but in some extreme/misconfiguration cases.
606 int ubifs_garbage_collect(struct ubifs_info *c, int anyway)
608 int i, err, ret, min_space = c->dead_wm;
609 struct ubifs_lprops lp;
610 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
612 ubifs_assert_cmt_locked(c);
614 if (ubifs_gc_should_commit(c))
617 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
624 /* We expect the write-buffer to be empty on entry */
625 ubifs_assert(!wbuf->used);
628 int space_before = c->leb_size - wbuf->offs - wbuf->used;
633 /* Give the commit an opportunity to run */
634 if (ubifs_gc_should_commit(c)) {
639 if (i > SOFT_LEBS_LIMIT && !list_empty(&c->idx_gc)) {
641 * We've done enough iterations. Indexing LEBs were
642 * moved and will be available after the commit.
644 dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN");
645 ubifs_commit_required(c);
650 if (i > HARD_LEBS_LIMIT) {
652 * We've moved too many LEBs and have not made
655 dbg_gc("hard limit, -ENOSPC");
661 * Empty and freeable LEBs can turn up while we waited for
662 * the wbuf lock, or while we have been running GC. In that
663 * case, we should just return one of those instead of
664 * continuing to GC dirty LEBs. Hence we request
665 * 'ubifs_find_dirty_leb()' to return an empty LEB if it can.
667 ret = ubifs_find_dirty_leb(c, &lp, min_space, anyway ? 0 : 1);
670 dbg_gc("no more dirty LEBs");
674 dbg_gc("found LEB %d: free %d, dirty %d, sum %d "
675 "(min. space %d)", lp.lnum, lp.free, lp.dirty,
676 lp.free + lp.dirty, min_space);
678 if (lp.free + lp.dirty == c->leb_size) {
679 /* An empty LEB was returned */
680 dbg_gc("LEB %d is free, return it", lp.lnum);
682 * ubifs_find_dirty_leb() doesn't return freeable index
685 ubifs_assert(!(lp.flags & LPROPS_INDEX));
686 if (lp.free != c->leb_size) {
688 * Write buffers must be sync'd before
689 * unmapping freeable LEBs, because one of them
690 * may contain data which obsoletes something
693 ret = gc_sync_wbufs(c);
696 ret = ubifs_change_one_lp(c, lp.lnum,
697 c->leb_size, 0, 0, 0,
702 ret = ubifs_leb_unmap(c, lp.lnum);
709 space_before = c->leb_size - wbuf->offs - wbuf->used;
710 if (wbuf->lnum == -1)
713 ret = ubifs_garbage_collect_leb(c, &lp);
715 if (ret == -EAGAIN) {
717 * This is not error, so we have to return the
718 * LEB to lprops. But if 'ubifs_return_leb()'
719 * fails, its failure code is propagated to the
720 * caller instead of the original '-EAGAIN'.
722 err = ubifs_return_leb(c, lp.lnum);
730 if (ret == LEB_FREED) {
731 /* An LEB has been freed and is ready for use */
732 dbg_gc("LEB %d freed, return", lp.lnum);
737 if (ret == LEB_FREED_IDX) {
739 * This was an indexing LEB and it cannot be
740 * immediately used. And instead of requesting the
741 * commit straight away, we try to garbage collect some
744 dbg_gc("indexing LEB %d freed, continue", lp.lnum);
748 ubifs_assert(ret == LEB_RETAINED);
749 space_after = c->leb_size - wbuf->offs - wbuf->used;
750 dbg_gc("LEB %d retained, freed %d bytes", lp.lnum,
751 space_after - space_before);
753 if (space_after > space_before) {
754 /* GC makes progress, keep working */
756 if (min_space < c->dead_wm)
757 min_space = c->dead_wm;
761 dbg_gc("did not make progress");
764 * GC moved an LEB bud have not done any progress. This means
765 * that the previous GC head LEB contained too few free space
766 * and the LEB which was GC'ed contained only large nodes which
767 * did not fit that space.
769 * We can do 2 things:
770 * 1. pick another LEB in a hope it'll contain a small node
771 * which will fit the space we have at the end of current GC
772 * head LEB, but there is no guarantee, so we try this out
773 * unless we have already been working for too long;
774 * 2. request an LEB with more dirty space, which will force
775 * 'ubifs_find_dirty_leb()' to start scanning the lprops
776 * table, instead of just picking one from the heap
777 * (previously it already picked the dirtiest LEB).
779 if (i < SOFT_LEBS_LIMIT) {
785 if (min_space > c->dark_wm)
786 min_space = c->dark_wm;
787 dbg_gc("set min. space to %d", min_space);
790 if (ret == -ENOSPC && !list_empty(&c->idx_gc)) {
791 dbg_gc("no space, some index LEBs GC'ed, -EAGAIN");
792 ubifs_commit_required(c);
796 err = ubifs_wbuf_sync_nolock(wbuf);
798 err = ubifs_leb_unmap(c, c->gc_lnum);
804 mutex_unlock(&wbuf->io_mutex);
808 ubifs_assert(ret < 0);
809 ubifs_assert(ret != -ENOSPC && ret != -EAGAIN);
810 ubifs_wbuf_sync_nolock(wbuf);
811 ubifs_ro_mode(c, ret);
812 mutex_unlock(&wbuf->io_mutex);
813 ubifs_return_leb(c, lp.lnum);
818 * ubifs_gc_start_commit - garbage collection at start of commit.
819 * @c: UBIFS file-system description object
821 * If a LEB has only dirty and free space, then we may safely unmap it and make
822 * it free. Note, we cannot do this with indexing LEBs because dirty space may
823 * correspond index nodes that are required for recovery. In that case, the
824 * LEB cannot be unmapped until after the next commit.
826 * This function returns %0 upon success and a negative error code upon failure.
828 int ubifs_gc_start_commit(struct ubifs_info *c)
830 struct ubifs_gced_idx_leb *idx_gc;
831 const struct ubifs_lprops *lp;
837 * Unmap (non-index) freeable LEBs. Note that recovery requires that all
838 * wbufs are sync'd before this, which is done in 'do_commit()'.
841 lp = ubifs_fast_find_freeable(c);
848 ubifs_assert(!(lp->flags & LPROPS_TAKEN));
849 ubifs_assert(!(lp->flags & LPROPS_INDEX));
850 err = ubifs_leb_unmap(c, lp->lnum);
853 lp = ubifs_change_lp(c, lp, c->leb_size, 0, lp->flags, 0);
858 ubifs_assert(!(lp->flags & LPROPS_TAKEN));
859 ubifs_assert(!(lp->flags & LPROPS_INDEX));
862 /* Mark GC'd index LEBs OK to unmap after this commit finishes */
863 list_for_each_entry(idx_gc, &c->idx_gc, list)
866 /* Record index freeable LEBs for unmapping after commit */
868 lp = ubifs_fast_find_frdi_idx(c);
875 idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
880 ubifs_assert(!(lp->flags & LPROPS_TAKEN));
881 ubifs_assert(lp->flags & LPROPS_INDEX);
882 /* Don't release the LEB until after the next commit */
883 flags = (lp->flags | LPROPS_TAKEN) ^ LPROPS_INDEX;
884 lp = ubifs_change_lp(c, lp, c->leb_size, 0, flags, 1);
890 ubifs_assert(lp->flags & LPROPS_TAKEN);
891 ubifs_assert(!(lp->flags & LPROPS_INDEX));
892 idx_gc->lnum = lp->lnum;
894 list_add(&idx_gc->list, &c->idx_gc);
897 ubifs_release_lprops(c);
902 * ubifs_gc_end_commit - garbage collection at end of commit.
903 * @c: UBIFS file-system description object
905 * This function completes out-of-place garbage collection of index LEBs.
907 int ubifs_gc_end_commit(struct ubifs_info *c)
909 struct ubifs_gced_idx_leb *idx_gc, *tmp;
910 struct ubifs_wbuf *wbuf;
913 wbuf = &c->jheads[GCHD].wbuf;
914 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
915 list_for_each_entry_safe(idx_gc, tmp, &c->idx_gc, list)
917 dbg_gc("LEB %d", idx_gc->lnum);
918 err = ubifs_leb_unmap(c, idx_gc->lnum);
921 err = ubifs_change_one_lp(c, idx_gc->lnum, LPROPS_NC,
922 LPROPS_NC, 0, LPROPS_TAKEN, -1);
925 list_del(&idx_gc->list);
929 mutex_unlock(&wbuf->io_mutex);
934 * ubifs_destroy_idx_gc - destroy idx_gc list.
935 * @c: UBIFS file-system description object
937 * This function destroys the @c->idx_gc list. It is called when unmounting
938 * so locks are not needed. Returns zero in case of success and a negative
939 * error code in case of failure.
941 void ubifs_destroy_idx_gc(struct ubifs_info *c)
943 while (!list_empty(&c->idx_gc)) {
944 struct ubifs_gced_idx_leb *idx_gc;
946 idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb,
949 list_del(&idx_gc->list);
955 * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list.
956 * @c: UBIFS file-system description object
958 * Called during start commit so locks are not needed.
960 int ubifs_get_idx_gc_leb(struct ubifs_info *c)
962 struct ubifs_gced_idx_leb *idx_gc;
965 if (list_empty(&c->idx_gc))
967 idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb, list);
969 /* c->idx_gc_cnt is updated by the caller when lprops are updated */
970 list_del(&idx_gc->list);