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
;
128 sa
= list_entry(a
, struct ubifs_scan_node
, list
);
129 sb
= list_entry(b
, struct ubifs_scan_node
, list
);
130 ubifs_assert(key_type(c
, &sa
->key
) == UBIFS_DATA_KEY
);
131 ubifs_assert(key_type(c
, &sb
->key
) == UBIFS_DATA_KEY
);
133 inuma
= key_inum(c
, &sa
->key
);
134 inumb
= key_inum(c
, &sb
->key
);
136 if (inuma
== inumb
) {
137 unsigned int blka
= key_block(c
, &sa
->key
);
138 unsigned int blkb
= key_block(c
, &sb
->key
);
142 } else if (inuma
<= inumb
)
149 * nondata_nodes_cmp - compare 2 non-data nodes.
150 * @priv: UBIFS file-system description object
154 * This function compares nodes @a and @b. It makes sure that inode nodes go
155 * first and sorted by length in descending order. Directory entry nodes go
156 * after inode nodes and are sorted in ascending hash valuer order.
158 int nondata_nodes_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
162 struct ubifs_info
*c
= priv
;
163 struct ubifs_scan_node
*sa
, *sb
;
166 sa
= list_entry(a
, struct ubifs_scan_node
, list
);
167 sb
= list_entry(b
, struct ubifs_scan_node
, list
);
168 typea
= key_type(c
, &sa
->key
);
169 typeb
= key_type(c
, &sb
->key
);
170 ubifs_assert(typea
!= UBIFS_DATA_KEY
&& typeb
!= UBIFS_DATA_KEY
);
172 /* Inodes go before directory entries */
173 if (typea
== UBIFS_INO_KEY
) {
174 if (typeb
== UBIFS_INO_KEY
)
175 return sb
->len
- sa
->len
;
178 if (typeb
== UBIFS_INO_KEY
)
181 ubifs_assert(typea
== UBIFS_DENT_KEY
|| typea
== UBIFS_XENT_KEY
);
182 ubifs_assert(typeb
== UBIFS_DENT_KEY
|| typeb
== UBIFS_XENT_KEY
);
183 inuma
= key_inum(c
, &sa
->key
);
184 inumb
= key_inum(c
, &sb
->key
);
186 if (inuma
== inumb
) {
187 uint32_t hasha
= key_hash(c
, &sa
->key
);
188 uint32_t hashb
= key_hash(c
, &sb
->key
);
192 } else if (inuma
<= inumb
)
199 * sort_nodes - sort nodes for GC.
200 * @c: UBIFS file-system description object
201 * @sleb: describes nodes to sort and contains the result on exit
202 * @nondata: contains non-data nodes on exit
203 * @min: minimum node size is returned here
205 * This function sorts the list of inodes to garbage collect. First of all, it
206 * kills obsolete nodes and separates data and non-data nodes to the
207 * @sleb->nodes and @nondata lists correspondingly.
209 * Data nodes are then sorted in block number order - this is important for
210 * bulk-read; data nodes with lower inode number go before data nodes with
211 * higher inode number, and data nodes with lower block number go before data
212 * nodes with higher block number;
214 * Non-data nodes are sorted as follows.
215 * o First go inode nodes - they are sorted in descending length order.
216 * o Then go directory entry nodes - they are sorted in hash order, which
217 * should supposedly optimize 'readdir()'. Direntry nodes with lower parent
218 * inode number go before direntry nodes with higher parent inode number,
219 * and direntry nodes with lower name hash values go before direntry nodes
220 * with higher name hash values.
222 * This function returns zero in case of success and a negative error code in
225 static int sort_nodes(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
,
226 struct list_head
*nondata
, int *min
)
228 struct ubifs_scan_node
*snod
, *tmp
;
232 /* Separate data nodes and non-data nodes */
233 list_for_each_entry_safe(snod
, tmp
, &sleb
->nodes
, list
) {
236 ubifs_assert(snod
->type
!= UBIFS_IDX_NODE
);
237 ubifs_assert(snod
->type
!= UBIFS_REF_NODE
);
238 ubifs_assert(snod
->type
!= UBIFS_CS_NODE
);
240 err
= ubifs_tnc_has_node(c
, &snod
->key
, 0, sleb
->lnum
,
246 /* The node is obsolete, remove it from the list */
247 list_del(&snod
->list
);
252 if (snod
->len
< *min
)
255 if (key_type(c
, &snod
->key
) != UBIFS_DATA_KEY
)
256 list_move_tail(&snod
->list
, nondata
);
259 /* Sort data and non-data nodes */
260 list_sort(c
, &sleb
->nodes
, &data_nodes_cmp
);
261 list_sort(c
, nondata
, &nondata_nodes_cmp
);
266 * move_node - move a node.
267 * @c: UBIFS file-system description object
268 * @sleb: describes the LEB to move nodes from
269 * @snod: the mode to move
270 * @wbuf: write-buffer to move node to
272 * This function moves node @snod to @wbuf, changes TNC correspondingly, and
273 * destroys @snod. Returns zero in case of success and a negative error code in
276 static int move_node(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
,
277 struct ubifs_scan_node
*snod
, struct ubifs_wbuf
*wbuf
)
279 int err
, new_lnum
= wbuf
->lnum
, new_offs
= wbuf
->offs
+ wbuf
->used
;
282 err
= ubifs_wbuf_write_nolock(wbuf
, snod
->node
, snod
->len
);
286 err
= ubifs_tnc_replace(c
, &snod
->key
, sleb
->lnum
,
287 snod
->offs
, new_lnum
, new_offs
,
289 list_del(&snod
->list
);
295 * move_nodes - move nodes.
296 * @c: UBIFS file-system description object
297 * @sleb: describes the LEB to move nodes from
299 * This function moves valid nodes from data LEB described by @sleb to the GC
300 * journal head. This function returns zero in case of success, %-EAGAIN if
301 * commit is required, and other negative error codes in case of other
304 static int move_nodes(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
)
308 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
310 if (wbuf
->lnum
== -1) {
312 * The GC journal head is not set, because it is the first GC
313 * invocation since mount.
315 err
= switch_gc_head(c
);
320 err
= sort_nodes(c
, sleb
, &nondata
, &min
);
324 /* Write nodes to their new location. Use the first-fit strategy */
327 struct ubifs_scan_node
*snod
, *tmp
;
329 /* Move data nodes */
330 list_for_each_entry_safe(snod
, tmp
, &sleb
->nodes
, list
) {
331 avail
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
332 if (snod
->len
> avail
)
334 * Do not skip data nodes in order to optimize
339 err
= move_node(c
, sleb
, snod
, wbuf
);
344 /* Move non-data nodes */
345 list_for_each_entry_safe(snod
, tmp
, &nondata
, list
) {
346 avail
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
350 if (snod
->len
> avail
) {
352 * Keep going only if this is an inode with
353 * some data. Otherwise stop and switch the GC
354 * head. IOW, we assume that data-less inode
355 * nodes and direntry nodes are roughly of the
358 if (key_type(c
, &snod
->key
) == UBIFS_DENT_KEY
||
359 snod
->len
== UBIFS_INO_NODE_SZ
)
364 err
= move_node(c
, sleb
, snod
, wbuf
);
369 if (list_empty(&sleb
->nodes
) && list_empty(&nondata
))
373 * Waste the rest of the space in the LEB and switch to the
376 err
= switch_gc_head(c
);
384 list_splice_tail(&nondata
, &sleb
->nodes
);
389 * gc_sync_wbufs - sync write-buffers for GC.
390 * @c: UBIFS file-system description object
392 * We must guarantee that obsoleting nodes are on flash. Unfortunately they may
393 * be in a write-buffer instead. That is, a node could be written to a
394 * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is
395 * erased before the write-buffer is sync'd and then there is an unclean
396 * unmount, then an existing node is lost. To avoid this, we sync all
399 * This function returns %0 on success or a negative error code on failure.
401 static int gc_sync_wbufs(struct ubifs_info
*c
)
405 for (i
= 0; i
< c
->jhead_cnt
; i
++) {
408 err
= ubifs_wbuf_sync(&c
->jheads
[i
].wbuf
);
416 * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock.
417 * @c: UBIFS file-system description object
418 * @lp: describes the LEB to garbage collect
420 * This function garbage-collects an LEB and returns one of the @LEB_FREED,
421 * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is
422 * required, and other negative error codes in case of failures.
424 int ubifs_garbage_collect_leb(struct ubifs_info
*c
, struct ubifs_lprops
*lp
)
426 struct ubifs_scan_leb
*sleb
;
427 struct ubifs_scan_node
*snod
;
428 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
429 int err
= 0, lnum
= lp
->lnum
;
431 ubifs_assert(c
->gc_lnum
!= -1 || wbuf
->offs
+ wbuf
->used
== 0 ||
433 ubifs_assert(c
->gc_lnum
!= lnum
);
434 ubifs_assert(wbuf
->lnum
!= lnum
);
437 * We scan the entire LEB even though we only really need to scan up to
438 * (c->leb_size - lp->free).
440 sleb
= ubifs_scan(c
, lnum
, 0, c
->sbuf
, 0);
442 return PTR_ERR(sleb
);
444 ubifs_assert(!list_empty(&sleb
->nodes
));
445 snod
= list_entry(sleb
->nodes
.next
, struct ubifs_scan_node
, list
);
447 if (snod
->type
== UBIFS_IDX_NODE
) {
448 struct ubifs_gced_idx_leb
*idx_gc
;
450 dbg_gc("indexing LEB %d (free %d, dirty %d)",
451 lnum
, lp
->free
, lp
->dirty
);
452 list_for_each_entry(snod
, &sleb
->nodes
, list
) {
453 struct ubifs_idx_node
*idx
= snod
->node
;
454 int level
= le16_to_cpu(idx
->level
);
456 ubifs_assert(snod
->type
== UBIFS_IDX_NODE
);
457 key_read(c
, ubifs_idx_key(c
, idx
), &snod
->key
);
458 err
= ubifs_dirty_idx_node(c
, &snod
->key
, level
, lnum
,
464 idx_gc
= kmalloc(sizeof(struct ubifs_gced_idx_leb
), GFP_NOFS
);
472 list_add(&idx_gc
->list
, &c
->idx_gc
);
475 * Don't release the LEB until after the next commit, because
476 * it may contain data which is needed for recovery. So
477 * although we freed this LEB, it will become usable only after
480 err
= ubifs_change_one_lp(c
, lnum
, c
->leb_size
, 0, 0,
486 dbg_gc("data LEB %d (free %d, dirty %d)",
487 lnum
, lp
->free
, lp
->dirty
);
489 err
= move_nodes(c
, sleb
);
493 err
= gc_sync_wbufs(c
);
497 err
= ubifs_change_one_lp(c
, lnum
, c
->leb_size
, 0, 0, 0, 0);
501 /* Allow for races with TNC */
507 if (c
->gc_lnum
== -1) {
511 err
= ubifs_wbuf_sync_nolock(wbuf
);
515 err
= ubifs_leb_unmap(c
, lnum
);
524 ubifs_scan_destroy(sleb
);
528 /* We may have moved at least some nodes so allow for races with TNC */
537 * ubifs_garbage_collect - UBIFS garbage collector.
538 * @c: UBIFS file-system description object
539 * @anyway: do GC even if there are free LEBs
541 * This function does out-of-place garbage collection. The return codes are:
542 * o positive LEB number if the LEB has been freed and may be used;
543 * o %-EAGAIN if the caller has to run commit;
544 * o %-ENOSPC if GC failed to make any progress;
545 * o other negative error codes in case of other errors.
547 * Garbage collector writes data to the journal when GC'ing data LEBs, and just
548 * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point
549 * commit may be required. But commit cannot be run from inside GC, because the
550 * caller might be holding the commit lock, so %-EAGAIN is returned instead;
551 * And this error code means that the caller has to run commit, and re-run GC
552 * if there is still no free space.
554 * There are many reasons why this function may return %-EAGAIN:
555 * o the log is full and there is no space to write an LEB reference for
557 * o the journal is too large and exceeds size limitations;
558 * o GC moved indexing LEBs, but they can be used only after the commit;
559 * o the shrinker fails to find clean znodes to free and requests the commit;
562 * Note, if the file-system is close to be full, this function may return
563 * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of
564 * the function. E.g., this happens if the limits on the journal size are too
565 * tough and GC writes too much to the journal before an LEB is freed. This
566 * might also mean that the journal is too large, and the TNC becomes to big,
567 * so that the shrinker is constantly called, finds not clean znodes to free,
568 * and requests commit. Well, this may also happen if the journal is all right,
569 * but another kernel process consumes too much memory. Anyway, infinite
570 * %-EAGAIN may happen, but in some extreme/misconfiguration cases.
572 int ubifs_garbage_collect(struct ubifs_info
*c
, int anyway
)
574 int i
, err
, ret
, min_space
= c
->dead_wm
;
575 struct ubifs_lprops lp
;
576 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
578 ubifs_assert_cmt_locked(c
);
580 if (ubifs_gc_should_commit(c
))
583 mutex_lock_nested(&wbuf
->io_mutex
, wbuf
->jhead
);
590 /* We expect the write-buffer to be empty on entry */
591 ubifs_assert(!wbuf
->used
);
594 int space_before
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
599 /* Give the commit an opportunity to run */
600 if (ubifs_gc_should_commit(c
)) {
605 if (i
> SOFT_LEBS_LIMIT
&& !list_empty(&c
->idx_gc
)) {
607 * We've done enough iterations. Indexing LEBs were
608 * moved and will be available after the commit.
610 dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN");
611 ubifs_commit_required(c
);
616 if (i
> HARD_LEBS_LIMIT
) {
618 * We've moved too many LEBs and have not made
621 dbg_gc("hard limit, -ENOSPC");
627 * Empty and freeable LEBs can turn up while we waited for
628 * the wbuf lock, or while we have been running GC. In that
629 * case, we should just return one of those instead of
630 * continuing to GC dirty LEBs. Hence we request
631 * 'ubifs_find_dirty_leb()' to return an empty LEB if it can.
633 ret
= ubifs_find_dirty_leb(c
, &lp
, min_space
, anyway
? 0 : 1);
636 dbg_gc("no more dirty LEBs");
640 dbg_gc("found LEB %d: free %d, dirty %d, sum %d "
641 "(min. space %d)", lp
.lnum
, lp
.free
, lp
.dirty
,
642 lp
.free
+ lp
.dirty
, min_space
);
644 if (lp
.free
+ lp
.dirty
== c
->leb_size
) {
645 /* An empty LEB was returned */
646 dbg_gc("LEB %d is free, return it", lp
.lnum
);
648 * ubifs_find_dirty_leb() doesn't return freeable index
651 ubifs_assert(!(lp
.flags
& LPROPS_INDEX
));
652 if (lp
.free
!= c
->leb_size
) {
654 * Write buffers must be sync'd before
655 * unmapping freeable LEBs, because one of them
656 * may contain data which obsoletes something
659 ret
= gc_sync_wbufs(c
);
662 ret
= ubifs_change_one_lp(c
, lp
.lnum
,
663 c
->leb_size
, 0, 0, 0,
668 ret
= ubifs_leb_unmap(c
, lp
.lnum
);
675 space_before
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
676 if (wbuf
->lnum
== -1)
679 ret
= ubifs_garbage_collect_leb(c
, &lp
);
681 if (ret
== -EAGAIN
) {
683 * This is not error, so we have to return the
684 * LEB to lprops. But if 'ubifs_return_leb()'
685 * fails, its failure code is propagated to the
686 * caller instead of the original '-EAGAIN'.
688 err
= ubifs_return_leb(c
, lp
.lnum
);
696 if (ret
== LEB_FREED
) {
697 /* An LEB has been freed and is ready for use */
698 dbg_gc("LEB %d freed, return", lp
.lnum
);
703 if (ret
== LEB_FREED_IDX
) {
705 * This was an indexing LEB and it cannot be
706 * immediately used. And instead of requesting the
707 * commit straight away, we try to garbage collect some
710 dbg_gc("indexing LEB %d freed, continue", lp
.lnum
);
714 ubifs_assert(ret
== LEB_RETAINED
);
715 space_after
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
716 dbg_gc("LEB %d retained, freed %d bytes", lp
.lnum
,
717 space_after
- space_before
);
719 if (space_after
> space_before
) {
720 /* GC makes progress, keep working */
722 if (min_space
< c
->dead_wm
)
723 min_space
= c
->dead_wm
;
727 dbg_gc("did not make progress");
730 * GC moved an LEB bud have not done any progress. This means
731 * that the previous GC head LEB contained too few free space
732 * and the LEB which was GC'ed contained only large nodes which
733 * did not fit that space.
735 * We can do 2 things:
736 * 1. pick another LEB in a hope it'll contain a small node
737 * which will fit the space we have at the end of current GC
738 * head LEB, but there is no guarantee, so we try this out
739 * unless we have already been working for too long;
740 * 2. request an LEB with more dirty space, which will force
741 * 'ubifs_find_dirty_leb()' to start scanning the lprops
742 * table, instead of just picking one from the heap
743 * (previously it already picked the dirtiest LEB).
745 if (i
< SOFT_LEBS_LIMIT
) {
751 if (min_space
> c
->dark_wm
)
752 min_space
= c
->dark_wm
;
753 dbg_gc("set min. space to %d", min_space
);
756 if (ret
== -ENOSPC
&& !list_empty(&c
->idx_gc
)) {
757 dbg_gc("no space, some index LEBs GC'ed, -EAGAIN");
758 ubifs_commit_required(c
);
762 err
= ubifs_wbuf_sync_nolock(wbuf
);
764 err
= ubifs_leb_unmap(c
, c
->gc_lnum
);
770 mutex_unlock(&wbuf
->io_mutex
);
774 ubifs_assert(ret
< 0);
775 ubifs_assert(ret
!= -ENOSPC
&& ret
!= -EAGAIN
);
776 ubifs_wbuf_sync_nolock(wbuf
);
777 ubifs_ro_mode(c
, ret
);
778 mutex_unlock(&wbuf
->io_mutex
);
779 ubifs_return_leb(c
, lp
.lnum
);
784 * ubifs_gc_start_commit - garbage collection at start of commit.
785 * @c: UBIFS file-system description object
787 * If a LEB has only dirty and free space, then we may safely unmap it and make
788 * it free. Note, we cannot do this with indexing LEBs because dirty space may
789 * correspond index nodes that are required for recovery. In that case, the
790 * LEB cannot be unmapped until after the next commit.
792 * This function returns %0 upon success and a negative error code upon failure.
794 int ubifs_gc_start_commit(struct ubifs_info
*c
)
796 struct ubifs_gced_idx_leb
*idx_gc
;
797 const struct ubifs_lprops
*lp
;
803 * Unmap (non-index) freeable LEBs. Note that recovery requires that all
804 * wbufs are sync'd before this, which is done in 'do_commit()'.
807 lp
= ubifs_fast_find_freeable(c
);
814 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
815 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
816 err
= ubifs_leb_unmap(c
, lp
->lnum
);
819 lp
= ubifs_change_lp(c
, lp
, c
->leb_size
, 0, lp
->flags
, 0);
824 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
825 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
828 /* Mark GC'd index LEBs OK to unmap after this commit finishes */
829 list_for_each_entry(idx_gc
, &c
->idx_gc
, list
)
832 /* Record index freeable LEBs for unmapping after commit */
834 lp
= ubifs_fast_find_frdi_idx(c
);
841 idx_gc
= kmalloc(sizeof(struct ubifs_gced_idx_leb
), GFP_NOFS
);
846 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
847 ubifs_assert(lp
->flags
& LPROPS_INDEX
);
848 /* Don't release the LEB until after the next commit */
849 flags
= (lp
->flags
| LPROPS_TAKEN
) ^ LPROPS_INDEX
;
850 lp
= ubifs_change_lp(c
, lp
, c
->leb_size
, 0, flags
, 1);
856 ubifs_assert(lp
->flags
& LPROPS_TAKEN
);
857 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
858 idx_gc
->lnum
= lp
->lnum
;
860 list_add(&idx_gc
->list
, &c
->idx_gc
);
863 ubifs_release_lprops(c
);
868 * ubifs_gc_end_commit - garbage collection at end of commit.
869 * @c: UBIFS file-system description object
871 * This function completes out-of-place garbage collection of index LEBs.
873 int ubifs_gc_end_commit(struct ubifs_info
*c
)
875 struct ubifs_gced_idx_leb
*idx_gc
, *tmp
;
876 struct ubifs_wbuf
*wbuf
;
879 wbuf
= &c
->jheads
[GCHD
].wbuf
;
880 mutex_lock_nested(&wbuf
->io_mutex
, wbuf
->jhead
);
881 list_for_each_entry_safe(idx_gc
, tmp
, &c
->idx_gc
, list
)
883 dbg_gc("LEB %d", idx_gc
->lnum
);
884 err
= ubifs_leb_unmap(c
, idx_gc
->lnum
);
887 err
= ubifs_change_one_lp(c
, idx_gc
->lnum
, LPROPS_NC
,
888 LPROPS_NC
, 0, LPROPS_TAKEN
, -1);
891 list_del(&idx_gc
->list
);
895 mutex_unlock(&wbuf
->io_mutex
);
900 * ubifs_destroy_idx_gc - destroy idx_gc list.
901 * @c: UBIFS file-system description object
903 * This function destroys the @c->idx_gc list. It is called when unmounting
904 * so locks are not needed. Returns zero in case of success and a negative
905 * error code in case of failure.
907 void ubifs_destroy_idx_gc(struct ubifs_info
*c
)
909 while (!list_empty(&c
->idx_gc
)) {
910 struct ubifs_gced_idx_leb
*idx_gc
;
912 idx_gc
= list_entry(c
->idx_gc
.next
, struct ubifs_gced_idx_leb
,
915 list_del(&idx_gc
->list
);
921 * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list.
922 * @c: UBIFS file-system description object
924 * Called during start commit so locks are not needed.
926 int ubifs_get_idx_gc_leb(struct ubifs_info
*c
)
928 struct ubifs_gced_idx_leb
*idx_gc
;
931 if (list_empty(&c
->idx_gc
))
933 idx_gc
= list_entry(c
->idx_gc
.next
, struct ubifs_gced_idx_leb
, list
);
935 /* c->idx_gc_cnt is updated by the caller when lprops are updated */
936 list_del(&idx_gc
->list
);
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