]>
git.ipfire.org Git - thirdparty/u-boot.git/blob - fs/ubifs/gc.c
1 // SPDX-License-Identifier: GPL-2.0
3 * This file is part of UBIFS.
5 * Copyright (C) 2006-2008 Nokia Corporation.
7 * Authors: Adrian Hunter
8 * Artem Bityutskiy (Битюцкий Артём)
12 * This file implements garbage collection. The procedure for garbage collection
13 * is different depending on whether a LEB as an index LEB (contains index
14 * nodes) or not. For non-index LEBs, garbage collection finds a LEB which
15 * contains a lot of dirty space (obsolete nodes), and copies the non-obsolete
16 * nodes to the journal, at which point the garbage-collected LEB is free to be
17 * reused. For index LEBs, garbage collection marks the non-obsolete index nodes
18 * dirty in the TNC, and after the next commit, the garbage-collected LEB is
19 * to be reused. Garbage collection will cause the number of dirty index nodes
20 * to grow, however sufficient space is reserved for the index to ensure the
21 * commit will never run out of space.
23 * Notes about dead watermark. At current UBIFS implementation we assume that
24 * LEBs which have less than @c->dead_wm bytes of free + dirty space are full
25 * and not worth garbage-collecting. The dead watermark is one min. I/O unit
26 * size, or min. UBIFS node size, depending on what is greater. Indeed, UBIFS
27 * Garbage Collector has to synchronize the GC head's write buffer before
28 * returning, so this is about wasting one min. I/O unit. However, UBIFS GC can
29 * actually reclaim even very small pieces of dirty space by garbage collecting
30 * enough dirty LEBs, but we do not bother doing this at this implementation.
32 * Notes about dark watermark. The results of GC work depends on how big are
33 * the UBIFS nodes GC deals with. Large nodes make GC waste more space. Indeed,
34 * if GC move data from LEB A to LEB B and nodes in LEB A are large, GC would
35 * have to waste large pieces of free space at the end of LEB B, because nodes
36 * from LEB A would not fit. And the worst situation is when all nodes are of
37 * maximum size. So dark watermark is the amount of free + dirty space in LEB
38 * which are guaranteed to be reclaimable. If LEB has less space, the GC might
39 * be unable to reclaim it. So, LEBs with free + dirty greater than dark
40 * watermark are "good" LEBs from GC's point of few. The other LEBs are not so
41 * good, and GC takes extra care when moving them.
44 #include <linux/slab.h>
45 #include <linux/pagemap.h>
46 #include <linux/list_sort.h>
52 * GC may need to move more than one LEB to make progress. The below constants
53 * define "soft" and "hard" limits on the number of LEBs the garbage collector
56 #define SOFT_LEBS_LIMIT 4
57 #define HARD_LEBS_LIMIT 32
60 * switch_gc_head - switch the garbage collection journal head.
61 * @c: UBIFS file-system description object
62 * @buf: buffer to write
63 * @len: length of the buffer to write
64 * @lnum: LEB number written is returned here
65 * @offs: offset written is returned here
67 * This function switch the GC head to the next LEB which is reserved in
68 * @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required,
69 * and other negative error code in case of failures.
71 static int switch_gc_head(struct ubifs_info
*c
)
73 int err
, gc_lnum
= c
->gc_lnum
;
74 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
76 ubifs_assert(gc_lnum
!= -1);
77 dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)",
78 wbuf
->lnum
, wbuf
->offs
+ wbuf
->used
, gc_lnum
,
79 c
->leb_size
- wbuf
->offs
- wbuf
->used
);
81 err
= ubifs_wbuf_sync_nolock(wbuf
);
86 * The GC write-buffer was synchronized, we may safely unmap
89 err
= ubifs_leb_unmap(c
, gc_lnum
);
93 err
= ubifs_wbuf_sync_nolock(wbuf
);
97 err
= ubifs_add_bud_to_log(c
, GCHD
, gc_lnum
, 0);
102 err
= ubifs_wbuf_seek_nolock(wbuf
, gc_lnum
, 0);
107 * data_nodes_cmp - compare 2 data nodes.
108 * @priv: UBIFS file-system description object
109 * @a: first data node
110 * @a: second data node
112 * This function compares data nodes @a and @b. Returns %1 if @a has greater
113 * inode or block number, and %-1 otherwise.
115 static int data_nodes_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
118 struct ubifs_info
*c
= priv
;
119 struct ubifs_scan_node
*sa
, *sb
;
125 sa
= list_entry(a
, struct ubifs_scan_node
, list
);
126 sb
= list_entry(b
, struct ubifs_scan_node
, list
);
128 ubifs_assert(key_type(c
, &sa
->key
) == UBIFS_DATA_KEY
);
129 ubifs_assert(key_type(c
, &sb
->key
) == UBIFS_DATA_KEY
);
130 ubifs_assert(sa
->type
== UBIFS_DATA_NODE
);
131 ubifs_assert(sb
->type
== UBIFS_DATA_NODE
);
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 static int nondata_nodes_cmp(void *priv
, struct list_head
*a
,
162 struct ubifs_info
*c
= priv
;
163 struct ubifs_scan_node
*sa
, *sb
;
169 sa
= list_entry(a
, struct ubifs_scan_node
, list
);
170 sb
= list_entry(b
, struct ubifs_scan_node
, list
);
172 ubifs_assert(key_type(c
, &sa
->key
) != UBIFS_DATA_KEY
&&
173 key_type(c
, &sb
->key
) != UBIFS_DATA_KEY
);
174 ubifs_assert(sa
->type
!= UBIFS_DATA_NODE
&&
175 sb
->type
!= UBIFS_DATA_NODE
);
177 /* Inodes go before directory entries */
178 if (sa
->type
== UBIFS_INO_NODE
) {
179 if (sb
->type
== UBIFS_INO_NODE
)
180 return sb
->len
- sa
->len
;
183 if (sb
->type
== UBIFS_INO_NODE
)
186 ubifs_assert(key_type(c
, &sa
->key
) == UBIFS_DENT_KEY
||
187 key_type(c
, &sa
->key
) == UBIFS_XENT_KEY
);
188 ubifs_assert(key_type(c
, &sb
->key
) == UBIFS_DENT_KEY
||
189 key_type(c
, &sb
->key
) == UBIFS_XENT_KEY
);
190 ubifs_assert(sa
->type
== UBIFS_DENT_NODE
||
191 sa
->type
== UBIFS_XENT_NODE
);
192 ubifs_assert(sb
->type
== UBIFS_DENT_NODE
||
193 sb
->type
== UBIFS_XENT_NODE
);
195 inuma
= key_inum(c
, &sa
->key
);
196 inumb
= key_inum(c
, &sb
->key
);
198 if (inuma
== inumb
) {
199 uint32_t hasha
= key_hash(c
, &sa
->key
);
200 uint32_t hashb
= key_hash(c
, &sb
->key
);
204 } else if (inuma
<= inumb
)
211 * sort_nodes - sort nodes for GC.
212 * @c: UBIFS file-system description object
213 * @sleb: describes nodes to sort and contains the result on exit
214 * @nondata: contains non-data nodes on exit
215 * @min: minimum node size is returned here
217 * This function sorts the list of inodes to garbage collect. First of all, it
218 * kills obsolete nodes and separates data and non-data nodes to the
219 * @sleb->nodes and @nondata lists correspondingly.
221 * Data nodes are then sorted in block number order - this is important for
222 * bulk-read; data nodes with lower inode number go before data nodes with
223 * higher inode number, and data nodes with lower block number go before data
224 * nodes with higher block number;
226 * Non-data nodes are sorted as follows.
227 * o First go inode nodes - they are sorted in descending length order.
228 * o Then go directory entry nodes - they are sorted in hash order, which
229 * should supposedly optimize 'readdir()'. Direntry nodes with lower parent
230 * inode number go before direntry nodes with higher parent inode number,
231 * and direntry nodes with lower name hash values go before direntry nodes
232 * with higher name hash values.
234 * This function returns zero in case of success and a negative error code in
237 static int sort_nodes(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
,
238 struct list_head
*nondata
, int *min
)
241 struct ubifs_scan_node
*snod
, *tmp
;
245 /* Separate data nodes and non-data nodes */
246 list_for_each_entry_safe(snod
, tmp
, &sleb
->nodes
, list
) {
247 ubifs_assert(snod
->type
== UBIFS_INO_NODE
||
248 snod
->type
== UBIFS_DATA_NODE
||
249 snod
->type
== UBIFS_DENT_NODE
||
250 snod
->type
== UBIFS_XENT_NODE
||
251 snod
->type
== UBIFS_TRUN_NODE
);
253 if (snod
->type
!= UBIFS_INO_NODE
&&
254 snod
->type
!= UBIFS_DATA_NODE
&&
255 snod
->type
!= UBIFS_DENT_NODE
&&
256 snod
->type
!= UBIFS_XENT_NODE
) {
257 /* Probably truncation node, zap it */
258 list_del(&snod
->list
);
263 ubifs_assert(key_type(c
, &snod
->key
) == UBIFS_DATA_KEY
||
264 key_type(c
, &snod
->key
) == UBIFS_INO_KEY
||
265 key_type(c
, &snod
->key
) == UBIFS_DENT_KEY
||
266 key_type(c
, &snod
->key
) == UBIFS_XENT_KEY
);
268 err
= ubifs_tnc_has_node(c
, &snod
->key
, 0, sleb
->lnum
,
274 /* The node is obsolete, remove it from the list */
275 list_del(&snod
->list
);
280 if (snod
->len
< *min
)
283 if (key_type(c
, &snod
->key
) != UBIFS_DATA_KEY
)
284 list_move_tail(&snod
->list
, nondata
);
287 /* Sort data and non-data nodes */
288 list_sort(c
, &sleb
->nodes
, &data_nodes_cmp
);
289 list_sort(c
, nondata
, &nondata_nodes_cmp
);
291 err
= dbg_check_data_nodes_order(c
, &sleb
->nodes
);
294 err
= dbg_check_nondata_nodes_order(c
, nondata
);
301 * move_node - move a node.
302 * @c: UBIFS file-system description object
303 * @sleb: describes the LEB to move nodes from
304 * @snod: the mode to move
305 * @wbuf: write-buffer to move node to
307 * This function moves node @snod to @wbuf, changes TNC correspondingly, and
308 * destroys @snod. Returns zero in case of success and a negative error code in
311 static int move_node(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
,
312 struct ubifs_scan_node
*snod
, struct ubifs_wbuf
*wbuf
)
314 int err
, new_lnum
= wbuf
->lnum
, new_offs
= wbuf
->offs
+ wbuf
->used
;
317 err
= ubifs_wbuf_write_nolock(wbuf
, snod
->node
, snod
->len
);
321 err
= ubifs_tnc_replace(c
, &snod
->key
, sleb
->lnum
,
322 snod
->offs
, new_lnum
, new_offs
,
324 list_del(&snod
->list
);
330 * move_nodes - move nodes.
331 * @c: UBIFS file-system description object
332 * @sleb: describes the LEB to move nodes from
334 * This function moves valid nodes from data LEB described by @sleb to the GC
335 * journal head. This function returns zero in case of success, %-EAGAIN if
336 * commit is required, and other negative error codes in case of other
339 static int move_nodes(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
)
343 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
345 if (wbuf
->lnum
== -1) {
347 * The GC journal head is not set, because it is the first GC
348 * invocation since mount.
350 err
= switch_gc_head(c
);
355 err
= sort_nodes(c
, sleb
, &nondata
, &min
);
359 /* Write nodes to their new location. Use the first-fit strategy */
362 struct ubifs_scan_node
*snod
, *tmp
;
364 /* Move data nodes */
365 list_for_each_entry_safe(snod
, tmp
, &sleb
->nodes
, list
) {
366 avail
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
367 if (snod
->len
> avail
)
369 * Do not skip data nodes in order to optimize
374 err
= move_node(c
, sleb
, snod
, wbuf
);
379 /* Move non-data nodes */
380 list_for_each_entry_safe(snod
, tmp
, &nondata
, list
) {
381 avail
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
385 if (snod
->len
> avail
) {
387 * Keep going only if this is an inode with
388 * some data. Otherwise stop and switch the GC
389 * head. IOW, we assume that data-less inode
390 * nodes and direntry nodes are roughly of the
393 if (key_type(c
, &snod
->key
) == UBIFS_DENT_KEY
||
394 snod
->len
== UBIFS_INO_NODE_SZ
)
399 err
= move_node(c
, sleb
, snod
, wbuf
);
404 if (list_empty(&sleb
->nodes
) && list_empty(&nondata
))
408 * Waste the rest of the space in the LEB and switch to the
411 err
= switch_gc_head(c
);
419 list_splice_tail(&nondata
, &sleb
->nodes
);
424 * gc_sync_wbufs - sync write-buffers for GC.
425 * @c: UBIFS file-system description object
427 * We must guarantee that obsoleting nodes are on flash. Unfortunately they may
428 * be in a write-buffer instead. That is, a node could be written to a
429 * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is
430 * erased before the write-buffer is sync'd and then there is an unclean
431 * unmount, then an existing node is lost. To avoid this, we sync all
434 * This function returns %0 on success or a negative error code on failure.
436 static int gc_sync_wbufs(struct ubifs_info
*c
)
440 for (i
= 0; i
< c
->jhead_cnt
; i
++) {
443 err
= ubifs_wbuf_sync(&c
->jheads
[i
].wbuf
);
451 * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock.
452 * @c: UBIFS file-system description object
453 * @lp: describes the LEB to garbage collect
455 * This function garbage-collects an LEB and returns one of the @LEB_FREED,
456 * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is
457 * required, and other negative error codes in case of failures.
459 int ubifs_garbage_collect_leb(struct ubifs_info
*c
, struct ubifs_lprops
*lp
)
461 struct ubifs_scan_leb
*sleb
;
462 struct ubifs_scan_node
*snod
;
463 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
464 int err
= 0, lnum
= lp
->lnum
;
466 ubifs_assert(c
->gc_lnum
!= -1 || wbuf
->offs
+ wbuf
->used
== 0 ||
468 ubifs_assert(c
->gc_lnum
!= lnum
);
469 ubifs_assert(wbuf
->lnum
!= lnum
);
471 if (lp
->free
+ lp
->dirty
== c
->leb_size
) {
472 /* Special case - a free LEB */
473 dbg_gc("LEB %d is free, return it", lp
->lnum
);
474 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
476 if (lp
->free
!= c
->leb_size
) {
478 * Write buffers must be sync'd before unmapping
479 * freeable LEBs, because one of them may contain data
480 * which obsoletes something in 'lp->pnum'.
482 err
= gc_sync_wbufs(c
);
485 err
= ubifs_change_one_lp(c
, lp
->lnum
, c
->leb_size
,
490 err
= ubifs_leb_unmap(c
, lp
->lnum
);
494 if (c
->gc_lnum
== -1) {
503 * We scan the entire LEB even though we only really need to scan up to
504 * (c->leb_size - lp->free).
506 sleb
= ubifs_scan(c
, lnum
, 0, c
->sbuf
, 0);
508 return PTR_ERR(sleb
);
510 ubifs_assert(!list_empty(&sleb
->nodes
));
511 snod
= list_entry(sleb
->nodes
.next
, struct ubifs_scan_node
, list
);
513 if (snod
->type
== UBIFS_IDX_NODE
) {
514 struct ubifs_gced_idx_leb
*idx_gc
;
516 dbg_gc("indexing LEB %d (free %d, dirty %d)",
517 lnum
, lp
->free
, lp
->dirty
);
518 list_for_each_entry(snod
, &sleb
->nodes
, list
) {
519 struct ubifs_idx_node
*idx
= snod
->node
;
520 int level
= le16_to_cpu(idx
->level
);
522 ubifs_assert(snod
->type
== UBIFS_IDX_NODE
);
523 key_read(c
, ubifs_idx_key(c
, idx
), &snod
->key
);
524 err
= ubifs_dirty_idx_node(c
, &snod
->key
, level
, lnum
,
530 idx_gc
= kmalloc(sizeof(struct ubifs_gced_idx_leb
), GFP_NOFS
);
538 list_add(&idx_gc
->list
, &c
->idx_gc
);
541 * Don't release the LEB until after the next commit, because
542 * it may contain data which is needed for recovery. So
543 * although we freed this LEB, it will become usable only after
546 err
= ubifs_change_one_lp(c
, lnum
, c
->leb_size
, 0, 0,
552 dbg_gc("data LEB %d (free %d, dirty %d)",
553 lnum
, lp
->free
, lp
->dirty
);
555 err
= move_nodes(c
, sleb
);
559 err
= gc_sync_wbufs(c
);
563 err
= ubifs_change_one_lp(c
, lnum
, c
->leb_size
, 0, 0, 0, 0);
567 /* Allow for races with TNC */
573 if (c
->gc_lnum
== -1) {
577 err
= ubifs_wbuf_sync_nolock(wbuf
);
581 err
= ubifs_leb_unmap(c
, lnum
);
590 ubifs_scan_destroy(sleb
);
594 /* We may have moved at least some nodes so allow for races with TNC */
603 * ubifs_garbage_collect - UBIFS garbage collector.
604 * @c: UBIFS file-system description object
605 * @anyway: do GC even if there are free LEBs
607 * This function does out-of-place garbage collection. The return codes are:
608 * o positive LEB number if the LEB has been freed and may be used;
609 * o %-EAGAIN if the caller has to run commit;
610 * o %-ENOSPC if GC failed to make any progress;
611 * o other negative error codes in case of other errors.
613 * Garbage collector writes data to the journal when GC'ing data LEBs, and just
614 * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point
615 * commit may be required. But commit cannot be run from inside GC, because the
616 * caller might be holding the commit lock, so %-EAGAIN is returned instead;
617 * And this error code means that the caller has to run commit, and re-run GC
618 * if there is still no free space.
620 * There are many reasons why this function may return %-EAGAIN:
621 * o the log is full and there is no space to write an LEB reference for
623 * o the journal is too large and exceeds size limitations;
624 * o GC moved indexing LEBs, but they can be used only after the commit;
625 * o the shrinker fails to find clean znodes to free and requests the commit;
628 * Note, if the file-system is close to be full, this function may return
629 * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of
630 * the function. E.g., this happens if the limits on the journal size are too
631 * tough and GC writes too much to the journal before an LEB is freed. This
632 * might also mean that the journal is too large, and the TNC becomes to big,
633 * so that the shrinker is constantly called, finds not clean znodes to free,
634 * and requests commit. Well, this may also happen if the journal is all right,
635 * but another kernel process consumes too much memory. Anyway, infinite
636 * %-EAGAIN may happen, but in some extreme/misconfiguration cases.
638 int ubifs_garbage_collect(struct ubifs_info
*c
, int anyway
)
640 int i
, err
, ret
, min_space
= c
->dead_wm
;
641 struct ubifs_lprops lp
;
642 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
644 ubifs_assert_cmt_locked(c
);
645 ubifs_assert(!c
->ro_media
&& !c
->ro_mount
);
647 if (ubifs_gc_should_commit(c
))
650 mutex_lock_nested(&wbuf
->io_mutex
, wbuf
->jhead
);
657 /* We expect the write-buffer to be empty on entry */
658 ubifs_assert(!wbuf
->used
);
661 int space_before
, space_after
;
665 /* Give the commit an opportunity to run */
666 if (ubifs_gc_should_commit(c
)) {
671 if (i
> SOFT_LEBS_LIMIT
&& !list_empty(&c
->idx_gc
)) {
673 * We've done enough iterations. Indexing LEBs were
674 * moved and will be available after the commit.
676 dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN");
677 ubifs_commit_required(c
);
682 if (i
> HARD_LEBS_LIMIT
) {
684 * We've moved too many LEBs and have not made
687 dbg_gc("hard limit, -ENOSPC");
693 * Empty and freeable LEBs can turn up while we waited for
694 * the wbuf lock, or while we have been running GC. In that
695 * case, we should just return one of those instead of
696 * continuing to GC dirty LEBs. Hence we request
697 * 'ubifs_find_dirty_leb()' to return an empty LEB if it can.
699 ret
= ubifs_find_dirty_leb(c
, &lp
, min_space
, anyway
? 0 : 1);
702 dbg_gc("no more dirty LEBs");
706 dbg_gc("found LEB %d: free %d, dirty %d, sum %d (min. space %d)",
707 lp
.lnum
, lp
.free
, lp
.dirty
, lp
.free
+ lp
.dirty
,
710 space_before
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
711 if (wbuf
->lnum
== -1)
714 ret
= ubifs_garbage_collect_leb(c
, &lp
);
716 if (ret
== -EAGAIN
) {
718 * This is not error, so we have to return the
719 * LEB to lprops. But if 'ubifs_return_leb()'
720 * fails, its failure code is propagated to the
721 * caller instead of the original '-EAGAIN'.
723 err
= ubifs_return_leb(c
, lp
.lnum
);
731 if (ret
== LEB_FREED
) {
732 /* An LEB has been freed and is ready for use */
733 dbg_gc("LEB %d freed, return", lp
.lnum
);
738 if (ret
== LEB_FREED_IDX
) {
740 * This was an indexing LEB and it cannot be
741 * immediately used. And instead of requesting the
742 * commit straight away, we try to garbage collect some
745 dbg_gc("indexing LEB %d freed, continue", lp
.lnum
);
749 ubifs_assert(ret
== LEB_RETAINED
);
750 space_after
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
751 dbg_gc("LEB %d retained, freed %d bytes", lp
.lnum
,
752 space_after
- space_before
);
754 if (space_after
> space_before
) {
755 /* GC makes progress, keep working */
757 if (min_space
< c
->dead_wm
)
758 min_space
= c
->dead_wm
;
762 dbg_gc("did not make progress");
765 * GC moved an LEB bud have not done any progress. This means
766 * that the previous GC head LEB contained too few free space
767 * and the LEB which was GC'ed contained only large nodes which
768 * did not fit that space.
770 * We can do 2 things:
771 * 1. pick another LEB in a hope it'll contain a small node
772 * which will fit the space we have at the end of current GC
773 * head LEB, but there is no guarantee, so we try this out
774 * unless we have already been working for too long;
775 * 2. request an LEB with more dirty space, which will force
776 * 'ubifs_find_dirty_leb()' to start scanning the lprops
777 * table, instead of just picking one from the heap
778 * (previously it already picked the dirtiest LEB).
780 if (i
< SOFT_LEBS_LIMIT
) {
786 if (min_space
> c
->dark_wm
)
787 min_space
= c
->dark_wm
;
788 dbg_gc("set min. space to %d", min_space
);
791 if (ret
== -ENOSPC
&& !list_empty(&c
->idx_gc
)) {
792 dbg_gc("no space, some index LEBs GC'ed, -EAGAIN");
793 ubifs_commit_required(c
);
797 err
= ubifs_wbuf_sync_nolock(wbuf
);
799 err
= ubifs_leb_unmap(c
, c
->gc_lnum
);
805 mutex_unlock(&wbuf
->io_mutex
);
809 ubifs_assert(ret
< 0);
810 ubifs_assert(ret
!= -ENOSPC
&& ret
!= -EAGAIN
);
811 ubifs_wbuf_sync_nolock(wbuf
);
812 ubifs_ro_mode(c
, ret
);
813 mutex_unlock(&wbuf
->io_mutex
);
814 ubifs_return_leb(c
, lp
.lnum
);
819 * ubifs_gc_start_commit - garbage collection at start of commit.
820 * @c: UBIFS file-system description object
822 * If a LEB has only dirty and free space, then we may safely unmap it and make
823 * it free. Note, we cannot do this with indexing LEBs because dirty space may
824 * correspond index nodes that are required for recovery. In that case, the
825 * LEB cannot be unmapped until after the next commit.
827 * This function returns %0 upon success and a negative error code upon failure.
829 int ubifs_gc_start_commit(struct ubifs_info
*c
)
831 struct ubifs_gced_idx_leb
*idx_gc
;
832 const struct ubifs_lprops
*lp
;
838 * Unmap (non-index) freeable LEBs. Note that recovery requires that all
839 * wbufs are sync'd before this, which is done in 'do_commit()'.
842 lp
= ubifs_fast_find_freeable(c
);
849 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
850 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
851 err
= ubifs_leb_unmap(c
, lp
->lnum
);
854 lp
= ubifs_change_lp(c
, lp
, c
->leb_size
, 0, lp
->flags
, 0);
859 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
860 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
863 /* Mark GC'd index LEBs OK to unmap after this commit finishes */
864 list_for_each_entry(idx_gc
, &c
->idx_gc
, list
)
867 /* Record index freeable LEBs for unmapping after commit */
869 lp
= ubifs_fast_find_frdi_idx(c
);
876 idx_gc
= kmalloc(sizeof(struct ubifs_gced_idx_leb
), GFP_NOFS
);
881 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
882 ubifs_assert(lp
->flags
& LPROPS_INDEX
);
883 /* Don't release the LEB until after the next commit */
884 flags
= (lp
->flags
| LPROPS_TAKEN
) ^ LPROPS_INDEX
;
885 lp
= ubifs_change_lp(c
, lp
, c
->leb_size
, 0, flags
, 1);
891 ubifs_assert(lp
->flags
& LPROPS_TAKEN
);
892 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
893 idx_gc
->lnum
= lp
->lnum
;
895 list_add(&idx_gc
->list
, &c
->idx_gc
);
898 ubifs_release_lprops(c
);
903 * ubifs_gc_end_commit - garbage collection at end of commit.
904 * @c: UBIFS file-system description object
906 * This function completes out-of-place garbage collection of index LEBs.
908 int ubifs_gc_end_commit(struct ubifs_info
*c
)
910 struct ubifs_gced_idx_leb
*idx_gc
, *tmp
;
911 struct ubifs_wbuf
*wbuf
;
914 wbuf
= &c
->jheads
[GCHD
].wbuf
;
915 mutex_lock_nested(&wbuf
->io_mutex
, wbuf
->jhead
);
916 list_for_each_entry_safe(idx_gc
, tmp
, &c
->idx_gc
, list
)
918 dbg_gc("LEB %d", idx_gc
->lnum
);
919 err
= ubifs_leb_unmap(c
, idx_gc
->lnum
);
922 err
= ubifs_change_one_lp(c
, idx_gc
->lnum
, LPROPS_NC
,
923 LPROPS_NC
, 0, LPROPS_TAKEN
, -1);
926 list_del(&idx_gc
->list
);
930 mutex_unlock(&wbuf
->io_mutex
);
935 * ubifs_destroy_idx_gc - destroy idx_gc list.
936 * @c: UBIFS file-system description object
938 * This function destroys the @c->idx_gc list. It is called when unmounting
939 * so locks are not needed. Returns zero in case of success and a negative
940 * error code in case of failure.
942 void ubifs_destroy_idx_gc(struct ubifs_info
*c
)
944 while (!list_empty(&c
->idx_gc
)) {
945 struct ubifs_gced_idx_leb
*idx_gc
;
947 idx_gc
= list_entry(c
->idx_gc
.next
, struct ubifs_gced_idx_leb
,
950 list_del(&idx_gc
->list
);
956 * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list.
957 * @c: UBIFS file-system description object
959 * Called during start commit so locks are not needed.
961 int ubifs_get_idx_gc_leb(struct ubifs_info
*c
)
963 struct ubifs_gced_idx_leb
*idx_gc
;
966 if (list_empty(&c
->idx_gc
))
968 idx_gc
= list_entry(c
->idx_gc
.next
, struct ubifs_gced_idx_leb
, list
);
970 /* c->idx_gc_cnt is updated by the caller when lprops are updated */
971 list_del(&idx_gc
->list
);