]>
git.ipfire.org Git - people/ms/u-boot.git/blob - fs/ubifs/gc.c
2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
6 * SPDX-License-Identifier: GPL-2.0
8 * Authors: Adrian Hunter
9 * Artem Bityutskiy (Битюцкий Артём)
13 * This file implements garbage collection. The procedure for garbage collection
14 * is different depending on whether a LEB as an index LEB (contains index
15 * nodes) or not. For non-index LEBs, garbage collection finds a LEB which
16 * contains a lot of dirty space (obsolete nodes), and copies the non-obsolete
17 * nodes to the journal, at which point the garbage-collected LEB is free to be
18 * reused. For index LEBs, garbage collection marks the non-obsolete index nodes
19 * dirty in the TNC, and after the next commit, the garbage-collected LEB is
20 * to be reused. Garbage collection will cause the number of dirty index nodes
21 * to grow, however sufficient space is reserved for the index to ensure the
22 * commit will never run out of space.
24 * Notes about dead watermark. At current UBIFS implementation we assume that
25 * LEBs which have less than @c->dead_wm bytes of free + dirty space are full
26 * and not worth garbage-collecting. The dead watermark is one min. I/O unit
27 * size, or min. UBIFS node size, depending on what is greater. Indeed, UBIFS
28 * Garbage Collector has to synchronize the GC head's write buffer before
29 * returning, so this is about wasting one min. I/O unit. However, UBIFS GC can
30 * actually reclaim even very small pieces of dirty space by garbage collecting
31 * enough dirty LEBs, but we do not bother doing this at this implementation.
33 * Notes about dark watermark. The results of GC work depends on how big are
34 * the UBIFS nodes GC deals with. Large nodes make GC waste more space. Indeed,
35 * if GC move data from LEB A to LEB B and nodes in LEB A are large, GC would
36 * have to waste large pieces of free space at the end of LEB B, because nodes
37 * from LEB A would not fit. And the worst situation is when all nodes are of
38 * maximum size. So dark watermark is the amount of free + dirty space in LEB
39 * which are guaranteed to be reclaimable. If LEB has less space, the GC might
40 * be unable to reclaim it. So, LEBs with free + dirty greater than dark
41 * watermark are "good" LEBs from GC's point of few. The other LEBs are not so
42 * good, and GC takes extra care when moving them.
45 #include <linux/slab.h>
46 #include <linux/pagemap.h>
47 #include <linux/list_sort.h>
53 * GC may need to move more than one LEB to make progress. The below constants
54 * define "soft" and "hard" limits on the number of LEBs the garbage collector
57 #define SOFT_LEBS_LIMIT 4
58 #define HARD_LEBS_LIMIT 32
61 * switch_gc_head - switch the garbage collection journal head.
62 * @c: UBIFS file-system description object
63 * @buf: buffer to write
64 * @len: length of the buffer to write
65 * @lnum: LEB number written is returned here
66 * @offs: offset written is returned here
68 * This function switch the GC head to the next LEB which is reserved in
69 * @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required,
70 * and other negative error code in case of failures.
72 static int switch_gc_head(struct ubifs_info
*c
)
74 int err
, gc_lnum
= c
->gc_lnum
;
75 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
77 ubifs_assert(gc_lnum
!= -1);
78 dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)",
79 wbuf
->lnum
, wbuf
->offs
+ wbuf
->used
, gc_lnum
,
80 c
->leb_size
- wbuf
->offs
- wbuf
->used
);
82 err
= ubifs_wbuf_sync_nolock(wbuf
);
87 * The GC write-buffer was synchronized, we may safely unmap
90 err
= ubifs_leb_unmap(c
, gc_lnum
);
94 err
= ubifs_wbuf_sync_nolock(wbuf
);
98 err
= ubifs_add_bud_to_log(c
, GCHD
, gc_lnum
, 0);
103 err
= ubifs_wbuf_seek_nolock(wbuf
, gc_lnum
, 0);
108 * data_nodes_cmp - compare 2 data nodes.
109 * @priv: UBIFS file-system description object
110 * @a: first data node
111 * @a: second data node
113 * This function compares data nodes @a and @b. Returns %1 if @a has greater
114 * inode or block number, and %-1 otherwise.
116 static int data_nodes_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
119 struct ubifs_info
*c
= priv
;
120 struct ubifs_scan_node
*sa
, *sb
;
126 sa
= list_entry(a
, struct ubifs_scan_node
, list
);
127 sb
= list_entry(b
, struct ubifs_scan_node
, list
);
129 ubifs_assert(key_type(c
, &sa
->key
) == UBIFS_DATA_KEY
);
130 ubifs_assert(key_type(c
, &sb
->key
) == UBIFS_DATA_KEY
);
131 ubifs_assert(sa
->type
== UBIFS_DATA_NODE
);
132 ubifs_assert(sb
->type
== UBIFS_DATA_NODE
);
134 inuma
= key_inum(c
, &sa
->key
);
135 inumb
= key_inum(c
, &sb
->key
);
137 if (inuma
== inumb
) {
138 unsigned int blka
= key_block(c
, &sa
->key
);
139 unsigned int blkb
= key_block(c
, &sb
->key
);
143 } else if (inuma
<= inumb
)
150 * nondata_nodes_cmp - compare 2 non-data nodes.
151 * @priv: UBIFS file-system description object
155 * This function compares nodes @a and @b. It makes sure that inode nodes go
156 * first and sorted by length in descending order. Directory entry nodes go
157 * after inode nodes and are sorted in ascending hash valuer order.
159 static int nondata_nodes_cmp(void *priv
, struct list_head
*a
,
163 struct ubifs_info
*c
= priv
;
164 struct ubifs_scan_node
*sa
, *sb
;
170 sa
= list_entry(a
, struct ubifs_scan_node
, list
);
171 sb
= list_entry(b
, struct ubifs_scan_node
, list
);
173 ubifs_assert(key_type(c
, &sa
->key
) != UBIFS_DATA_KEY
&&
174 key_type(c
, &sb
->key
) != UBIFS_DATA_KEY
);
175 ubifs_assert(sa
->type
!= UBIFS_DATA_NODE
&&
176 sb
->type
!= UBIFS_DATA_NODE
);
178 /* Inodes go before directory entries */
179 if (sa
->type
== UBIFS_INO_NODE
) {
180 if (sb
->type
== UBIFS_INO_NODE
)
181 return sb
->len
- sa
->len
;
184 if (sb
->type
== UBIFS_INO_NODE
)
187 ubifs_assert(key_type(c
, &sa
->key
) == UBIFS_DENT_KEY
||
188 key_type(c
, &sa
->key
) == UBIFS_XENT_KEY
);
189 ubifs_assert(key_type(c
, &sb
->key
) == UBIFS_DENT_KEY
||
190 key_type(c
, &sb
->key
) == UBIFS_XENT_KEY
);
191 ubifs_assert(sa
->type
== UBIFS_DENT_NODE
||
192 sa
->type
== UBIFS_XENT_NODE
);
193 ubifs_assert(sb
->type
== UBIFS_DENT_NODE
||
194 sb
->type
== UBIFS_XENT_NODE
);
196 inuma
= key_inum(c
, &sa
->key
);
197 inumb
= key_inum(c
, &sb
->key
);
199 if (inuma
== inumb
) {
200 uint32_t hasha
= key_hash(c
, &sa
->key
);
201 uint32_t hashb
= key_hash(c
, &sb
->key
);
205 } else if (inuma
<= inumb
)
212 * sort_nodes - sort nodes for GC.
213 * @c: UBIFS file-system description object
214 * @sleb: describes nodes to sort and contains the result on exit
215 * @nondata: contains non-data nodes on exit
216 * @min: minimum node size is returned here
218 * This function sorts the list of inodes to garbage collect. First of all, it
219 * kills obsolete nodes and separates data and non-data nodes to the
220 * @sleb->nodes and @nondata lists correspondingly.
222 * Data nodes are then sorted in block number order - this is important for
223 * bulk-read; data nodes with lower inode number go before data nodes with
224 * higher inode number, and data nodes with lower block number go before data
225 * nodes with higher block number;
227 * Non-data nodes are sorted as follows.
228 * o First go inode nodes - they are sorted in descending length order.
229 * o Then go directory entry nodes - they are sorted in hash order, which
230 * should supposedly optimize 'readdir()'. Direntry nodes with lower parent
231 * inode number go before direntry nodes with higher parent inode number,
232 * and direntry nodes with lower name hash values go before direntry nodes
233 * with higher name hash values.
235 * This function returns zero in case of success and a negative error code in
238 static int sort_nodes(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
,
239 struct list_head
*nondata
, int *min
)
242 struct ubifs_scan_node
*snod
, *tmp
;
246 /* Separate data nodes and non-data nodes */
247 list_for_each_entry_safe(snod
, tmp
, &sleb
->nodes
, list
) {
248 ubifs_assert(snod
->type
== UBIFS_INO_NODE
||
249 snod
->type
== UBIFS_DATA_NODE
||
250 snod
->type
== UBIFS_DENT_NODE
||
251 snod
->type
== UBIFS_XENT_NODE
||
252 snod
->type
== UBIFS_TRUN_NODE
);
254 if (snod
->type
!= UBIFS_INO_NODE
&&
255 snod
->type
!= UBIFS_DATA_NODE
&&
256 snod
->type
!= UBIFS_DENT_NODE
&&
257 snod
->type
!= UBIFS_XENT_NODE
) {
258 /* Probably truncation node, zap it */
259 list_del(&snod
->list
);
264 ubifs_assert(key_type(c
, &snod
->key
) == UBIFS_DATA_KEY
||
265 key_type(c
, &snod
->key
) == UBIFS_INO_KEY
||
266 key_type(c
, &snod
->key
) == UBIFS_DENT_KEY
||
267 key_type(c
, &snod
->key
) == UBIFS_XENT_KEY
);
269 err
= ubifs_tnc_has_node(c
, &snod
->key
, 0, sleb
->lnum
,
275 /* The node is obsolete, remove it from the list */
276 list_del(&snod
->list
);
281 if (snod
->len
< *min
)
284 if (key_type(c
, &snod
->key
) != UBIFS_DATA_KEY
)
285 list_move_tail(&snod
->list
, nondata
);
288 /* Sort data and non-data nodes */
289 list_sort(c
, &sleb
->nodes
, &data_nodes_cmp
);
290 list_sort(c
, nondata
, &nondata_nodes_cmp
);
292 err
= dbg_check_data_nodes_order(c
, &sleb
->nodes
);
295 err
= dbg_check_nondata_nodes_order(c
, nondata
);
302 * move_node - move a node.
303 * @c: UBIFS file-system description object
304 * @sleb: describes the LEB to move nodes from
305 * @snod: the mode to move
306 * @wbuf: write-buffer to move node to
308 * This function moves node @snod to @wbuf, changes TNC correspondingly, and
309 * destroys @snod. Returns zero in case of success and a negative error code in
312 static int move_node(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
,
313 struct ubifs_scan_node
*snod
, struct ubifs_wbuf
*wbuf
)
315 int err
, new_lnum
= wbuf
->lnum
, new_offs
= wbuf
->offs
+ wbuf
->used
;
318 err
= ubifs_wbuf_write_nolock(wbuf
, snod
->node
, snod
->len
);
322 err
= ubifs_tnc_replace(c
, &snod
->key
, sleb
->lnum
,
323 snod
->offs
, new_lnum
, new_offs
,
325 list_del(&snod
->list
);
331 * move_nodes - move nodes.
332 * @c: UBIFS file-system description object
333 * @sleb: describes the LEB to move nodes from
335 * This function moves valid nodes from data LEB described by @sleb to the GC
336 * journal head. This function returns zero in case of success, %-EAGAIN if
337 * commit is required, and other negative error codes in case of other
340 static int move_nodes(struct ubifs_info
*c
, struct ubifs_scan_leb
*sleb
)
344 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
346 if (wbuf
->lnum
== -1) {
348 * The GC journal head is not set, because it is the first GC
349 * invocation since mount.
351 err
= switch_gc_head(c
);
356 err
= sort_nodes(c
, sleb
, &nondata
, &min
);
360 /* Write nodes to their new location. Use the first-fit strategy */
363 struct ubifs_scan_node
*snod
, *tmp
;
365 /* Move data nodes */
366 list_for_each_entry_safe(snod
, tmp
, &sleb
->nodes
, list
) {
367 avail
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
368 if (snod
->len
> avail
)
370 * Do not skip data nodes in order to optimize
375 err
= move_node(c
, sleb
, snod
, wbuf
);
380 /* Move non-data nodes */
381 list_for_each_entry_safe(snod
, tmp
, &nondata
, list
) {
382 avail
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
386 if (snod
->len
> avail
) {
388 * Keep going only if this is an inode with
389 * some data. Otherwise stop and switch the GC
390 * head. IOW, we assume that data-less inode
391 * nodes and direntry nodes are roughly of the
394 if (key_type(c
, &snod
->key
) == UBIFS_DENT_KEY
||
395 snod
->len
== UBIFS_INO_NODE_SZ
)
400 err
= move_node(c
, sleb
, snod
, wbuf
);
405 if (list_empty(&sleb
->nodes
) && list_empty(&nondata
))
409 * Waste the rest of the space in the LEB and switch to the
412 err
= switch_gc_head(c
);
420 list_splice_tail(&nondata
, &sleb
->nodes
);
425 * gc_sync_wbufs - sync write-buffers for GC.
426 * @c: UBIFS file-system description object
428 * We must guarantee that obsoleting nodes are on flash. Unfortunately they may
429 * be in a write-buffer instead. That is, a node could be written to a
430 * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is
431 * erased before the write-buffer is sync'd and then there is an unclean
432 * unmount, then an existing node is lost. To avoid this, we sync all
435 * This function returns %0 on success or a negative error code on failure.
437 static int gc_sync_wbufs(struct ubifs_info
*c
)
441 for (i
= 0; i
< c
->jhead_cnt
; i
++) {
444 err
= ubifs_wbuf_sync(&c
->jheads
[i
].wbuf
);
452 * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock.
453 * @c: UBIFS file-system description object
454 * @lp: describes the LEB to garbage collect
456 * This function garbage-collects an LEB and returns one of the @LEB_FREED,
457 * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is
458 * required, and other negative error codes in case of failures.
460 int ubifs_garbage_collect_leb(struct ubifs_info
*c
, struct ubifs_lprops
*lp
)
462 struct ubifs_scan_leb
*sleb
;
463 struct ubifs_scan_node
*snod
;
464 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
465 int err
= 0, lnum
= lp
->lnum
;
467 ubifs_assert(c
->gc_lnum
!= -1 || wbuf
->offs
+ wbuf
->used
== 0 ||
469 ubifs_assert(c
->gc_lnum
!= lnum
);
470 ubifs_assert(wbuf
->lnum
!= lnum
);
472 if (lp
->free
+ lp
->dirty
== c
->leb_size
) {
473 /* Special case - a free LEB */
474 dbg_gc("LEB %d is free, return it", lp
->lnum
);
475 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
477 if (lp
->free
!= c
->leb_size
) {
479 * Write buffers must be sync'd before unmapping
480 * freeable LEBs, because one of them may contain data
481 * which obsoletes something in 'lp->pnum'.
483 err
= gc_sync_wbufs(c
);
486 err
= ubifs_change_one_lp(c
, lp
->lnum
, c
->leb_size
,
491 err
= ubifs_leb_unmap(c
, lp
->lnum
);
495 if (c
->gc_lnum
== -1) {
504 * We scan the entire LEB even though we only really need to scan up to
505 * (c->leb_size - lp->free).
507 sleb
= ubifs_scan(c
, lnum
, 0, c
->sbuf
, 0);
509 return PTR_ERR(sleb
);
511 ubifs_assert(!list_empty(&sleb
->nodes
));
512 snod
= list_entry(sleb
->nodes
.next
, struct ubifs_scan_node
, list
);
514 if (snod
->type
== UBIFS_IDX_NODE
) {
515 struct ubifs_gced_idx_leb
*idx_gc
;
517 dbg_gc("indexing LEB %d (free %d, dirty %d)",
518 lnum
, lp
->free
, lp
->dirty
);
519 list_for_each_entry(snod
, &sleb
->nodes
, list
) {
520 struct ubifs_idx_node
*idx
= snod
->node
;
521 int level
= le16_to_cpu(idx
->level
);
523 ubifs_assert(snod
->type
== UBIFS_IDX_NODE
);
524 key_read(c
, ubifs_idx_key(c
, idx
), &snod
->key
);
525 err
= ubifs_dirty_idx_node(c
, &snod
->key
, level
, lnum
,
531 idx_gc
= kmalloc(sizeof(struct ubifs_gced_idx_leb
), GFP_NOFS
);
539 list_add(&idx_gc
->list
, &c
->idx_gc
);
542 * Don't release the LEB until after the next commit, because
543 * it may contain data which is needed for recovery. So
544 * although we freed this LEB, it will become usable only after
547 err
= ubifs_change_one_lp(c
, lnum
, c
->leb_size
, 0, 0,
553 dbg_gc("data LEB %d (free %d, dirty %d)",
554 lnum
, lp
->free
, lp
->dirty
);
556 err
= move_nodes(c
, sleb
);
560 err
= gc_sync_wbufs(c
);
564 err
= ubifs_change_one_lp(c
, lnum
, c
->leb_size
, 0, 0, 0, 0);
568 /* Allow for races with TNC */
574 if (c
->gc_lnum
== -1) {
578 err
= ubifs_wbuf_sync_nolock(wbuf
);
582 err
= ubifs_leb_unmap(c
, lnum
);
591 ubifs_scan_destroy(sleb
);
595 /* We may have moved at least some nodes so allow for races with TNC */
604 * ubifs_garbage_collect - UBIFS garbage collector.
605 * @c: UBIFS file-system description object
606 * @anyway: do GC even if there are free LEBs
608 * This function does out-of-place garbage collection. The return codes are:
609 * o positive LEB number if the LEB has been freed and may be used;
610 * o %-EAGAIN if the caller has to run commit;
611 * o %-ENOSPC if GC failed to make any progress;
612 * o other negative error codes in case of other errors.
614 * Garbage collector writes data to the journal when GC'ing data LEBs, and just
615 * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point
616 * commit may be required. But commit cannot be run from inside GC, because the
617 * caller might be holding the commit lock, so %-EAGAIN is returned instead;
618 * And this error code means that the caller has to run commit, and re-run GC
619 * if there is still no free space.
621 * There are many reasons why this function may return %-EAGAIN:
622 * o the log is full and there is no space to write an LEB reference for
624 * o the journal is too large and exceeds size limitations;
625 * o GC moved indexing LEBs, but they can be used only after the commit;
626 * o the shrinker fails to find clean znodes to free and requests the commit;
629 * Note, if the file-system is close to be full, this function may return
630 * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of
631 * the function. E.g., this happens if the limits on the journal size are too
632 * tough and GC writes too much to the journal before an LEB is freed. This
633 * might also mean that the journal is too large, and the TNC becomes to big,
634 * so that the shrinker is constantly called, finds not clean znodes to free,
635 * and requests commit. Well, this may also happen if the journal is all right,
636 * but another kernel process consumes too much memory. Anyway, infinite
637 * %-EAGAIN may happen, but in some extreme/misconfiguration cases.
639 int ubifs_garbage_collect(struct ubifs_info
*c
, int anyway
)
641 int i
, err
, ret
, min_space
= c
->dead_wm
;
642 struct ubifs_lprops lp
;
643 struct ubifs_wbuf
*wbuf
= &c
->jheads
[GCHD
].wbuf
;
645 ubifs_assert_cmt_locked(c
);
646 ubifs_assert(!c
->ro_media
&& !c
->ro_mount
);
648 if (ubifs_gc_should_commit(c
))
651 mutex_lock_nested(&wbuf
->io_mutex
, wbuf
->jhead
);
658 /* We expect the write-buffer to be empty on entry */
659 ubifs_assert(!wbuf
->used
);
662 int space_before
, space_after
;
666 /* Give the commit an opportunity to run */
667 if (ubifs_gc_should_commit(c
)) {
672 if (i
> SOFT_LEBS_LIMIT
&& !list_empty(&c
->idx_gc
)) {
674 * We've done enough iterations. Indexing LEBs were
675 * moved and will be available after the commit.
677 dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN");
678 ubifs_commit_required(c
);
683 if (i
> HARD_LEBS_LIMIT
) {
685 * We've moved too many LEBs and have not made
688 dbg_gc("hard limit, -ENOSPC");
694 * Empty and freeable LEBs can turn up while we waited for
695 * the wbuf lock, or while we have been running GC. In that
696 * case, we should just return one of those instead of
697 * continuing to GC dirty LEBs. Hence we request
698 * 'ubifs_find_dirty_leb()' to return an empty LEB if it can.
700 ret
= ubifs_find_dirty_leb(c
, &lp
, min_space
, anyway
? 0 : 1);
703 dbg_gc("no more dirty LEBs");
707 dbg_gc("found LEB %d: free %d, dirty %d, sum %d (min. space %d)",
708 lp
.lnum
, lp
.free
, lp
.dirty
, lp
.free
+ lp
.dirty
,
711 space_before
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
712 if (wbuf
->lnum
== -1)
715 ret
= ubifs_garbage_collect_leb(c
, &lp
);
717 if (ret
== -EAGAIN
) {
719 * This is not error, so we have to return the
720 * LEB to lprops. But if 'ubifs_return_leb()'
721 * fails, its failure code is propagated to the
722 * caller instead of the original '-EAGAIN'.
724 err
= ubifs_return_leb(c
, lp
.lnum
);
732 if (ret
== LEB_FREED
) {
733 /* An LEB has been freed and is ready for use */
734 dbg_gc("LEB %d freed, return", lp
.lnum
);
739 if (ret
== LEB_FREED_IDX
) {
741 * This was an indexing LEB and it cannot be
742 * immediately used. And instead of requesting the
743 * commit straight away, we try to garbage collect some
746 dbg_gc("indexing LEB %d freed, continue", lp
.lnum
);
750 ubifs_assert(ret
== LEB_RETAINED
);
751 space_after
= c
->leb_size
- wbuf
->offs
- wbuf
->used
;
752 dbg_gc("LEB %d retained, freed %d bytes", lp
.lnum
,
753 space_after
- space_before
);
755 if (space_after
> space_before
) {
756 /* GC makes progress, keep working */
758 if (min_space
< c
->dead_wm
)
759 min_space
= c
->dead_wm
;
763 dbg_gc("did not make progress");
766 * GC moved an LEB bud have not done any progress. This means
767 * that the previous GC head LEB contained too few free space
768 * and the LEB which was GC'ed contained only large nodes which
769 * did not fit that space.
771 * We can do 2 things:
772 * 1. pick another LEB in a hope it'll contain a small node
773 * which will fit the space we have at the end of current GC
774 * head LEB, but there is no guarantee, so we try this out
775 * unless we have already been working for too long;
776 * 2. request an LEB with more dirty space, which will force
777 * 'ubifs_find_dirty_leb()' to start scanning the lprops
778 * table, instead of just picking one from the heap
779 * (previously it already picked the dirtiest LEB).
781 if (i
< SOFT_LEBS_LIMIT
) {
787 if (min_space
> c
->dark_wm
)
788 min_space
= c
->dark_wm
;
789 dbg_gc("set min. space to %d", min_space
);
792 if (ret
== -ENOSPC
&& !list_empty(&c
->idx_gc
)) {
793 dbg_gc("no space, some index LEBs GC'ed, -EAGAIN");
794 ubifs_commit_required(c
);
798 err
= ubifs_wbuf_sync_nolock(wbuf
);
800 err
= ubifs_leb_unmap(c
, c
->gc_lnum
);
806 mutex_unlock(&wbuf
->io_mutex
);
810 ubifs_assert(ret
< 0);
811 ubifs_assert(ret
!= -ENOSPC
&& ret
!= -EAGAIN
);
812 ubifs_wbuf_sync_nolock(wbuf
);
813 ubifs_ro_mode(c
, ret
);
814 mutex_unlock(&wbuf
->io_mutex
);
815 ubifs_return_leb(c
, lp
.lnum
);
820 * ubifs_gc_start_commit - garbage collection at start of commit.
821 * @c: UBIFS file-system description object
823 * If a LEB has only dirty and free space, then we may safely unmap it and make
824 * it free. Note, we cannot do this with indexing LEBs because dirty space may
825 * correspond index nodes that are required for recovery. In that case, the
826 * LEB cannot be unmapped until after the next commit.
828 * This function returns %0 upon success and a negative error code upon failure.
830 int ubifs_gc_start_commit(struct ubifs_info
*c
)
832 struct ubifs_gced_idx_leb
*idx_gc
;
833 const struct ubifs_lprops
*lp
;
839 * Unmap (non-index) freeable LEBs. Note that recovery requires that all
840 * wbufs are sync'd before this, which is done in 'do_commit()'.
843 lp
= ubifs_fast_find_freeable(c
);
850 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
851 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
852 err
= ubifs_leb_unmap(c
, lp
->lnum
);
855 lp
= ubifs_change_lp(c
, lp
, c
->leb_size
, 0, lp
->flags
, 0);
860 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
861 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
864 /* Mark GC'd index LEBs OK to unmap after this commit finishes */
865 list_for_each_entry(idx_gc
, &c
->idx_gc
, list
)
868 /* Record index freeable LEBs for unmapping after commit */
870 lp
= ubifs_fast_find_frdi_idx(c
);
877 idx_gc
= kmalloc(sizeof(struct ubifs_gced_idx_leb
), GFP_NOFS
);
882 ubifs_assert(!(lp
->flags
& LPROPS_TAKEN
));
883 ubifs_assert(lp
->flags
& LPROPS_INDEX
);
884 /* Don't release the LEB until after the next commit */
885 flags
= (lp
->flags
| LPROPS_TAKEN
) ^ LPROPS_INDEX
;
886 lp
= ubifs_change_lp(c
, lp
, c
->leb_size
, 0, flags
, 1);
892 ubifs_assert(lp
->flags
& LPROPS_TAKEN
);
893 ubifs_assert(!(lp
->flags
& LPROPS_INDEX
));
894 idx_gc
->lnum
= lp
->lnum
;
896 list_add(&idx_gc
->list
, &c
->idx_gc
);
899 ubifs_release_lprops(c
);
904 * ubifs_gc_end_commit - garbage collection at end of commit.
905 * @c: UBIFS file-system description object
907 * This function completes out-of-place garbage collection of index LEBs.
909 int ubifs_gc_end_commit(struct ubifs_info
*c
)
911 struct ubifs_gced_idx_leb
*idx_gc
, *tmp
;
912 struct ubifs_wbuf
*wbuf
;
915 wbuf
= &c
->jheads
[GCHD
].wbuf
;
916 mutex_lock_nested(&wbuf
->io_mutex
, wbuf
->jhead
);
917 list_for_each_entry_safe(idx_gc
, tmp
, &c
->idx_gc
, list
)
919 dbg_gc("LEB %d", idx_gc
->lnum
);
920 err
= ubifs_leb_unmap(c
, idx_gc
->lnum
);
923 err
= ubifs_change_one_lp(c
, idx_gc
->lnum
, LPROPS_NC
,
924 LPROPS_NC
, 0, LPROPS_TAKEN
, -1);
927 list_del(&idx_gc
->list
);
931 mutex_unlock(&wbuf
->io_mutex
);
936 * ubifs_destroy_idx_gc - destroy idx_gc list.
937 * @c: UBIFS file-system description object
939 * This function destroys the @c->idx_gc list. It is called when unmounting
940 * so locks are not needed. Returns zero in case of success and a negative
941 * error code in case of failure.
943 void ubifs_destroy_idx_gc(struct ubifs_info
*c
)
945 while (!list_empty(&c
->idx_gc
)) {
946 struct ubifs_gced_idx_leb
*idx_gc
;
948 idx_gc
= list_entry(c
->idx_gc
.next
, struct ubifs_gced_idx_leb
,
951 list_del(&idx_gc
->list
);
957 * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list.
958 * @c: UBIFS file-system description object
960 * Called during start commit so locks are not needed.
962 int ubifs_get_idx_gc_leb(struct ubifs_info
*c
)
964 struct ubifs_gced_idx_leb
*idx_gc
;
967 if (list_empty(&c
->idx_gc
))
969 idx_gc
= list_entry(c
->idx_gc
.next
, struct ubifs_gced_idx_leb
, list
);
971 /* c->idx_gc_cnt is updated by the caller when lprops are updated */
972 list_del(&idx_gc
->list
);