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-rw-r--r--fs/ubifs/gc.c773
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diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
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1/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
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.
9 *
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
13 * more details.
14 *
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
18 *
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
21 */
22
23/*
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.
34 */
35
36#include <linux/pagemap.h>
37#include "ubifs.h"
38
39/*
40 * GC tries to optimize the way it fit nodes to available space, and it sorts
41 * nodes a little. The below constants are watermarks which define "large",
42 * "medium", and "small" nodes.
43 */
44#define MEDIUM_NODE_WM (UBIFS_BLOCK_SIZE / 4)
45#define SMALL_NODE_WM UBIFS_MAX_DENT_NODE_SZ
46
47/*
48 * GC may need to move more then one LEB to make progress. The below constants
49 * define "soft" and "hard" limits on the number of LEBs the garbage collector
50 * may move.
51 */
52#define SOFT_LEBS_LIMIT 4
53#define HARD_LEBS_LIMIT 32
54
55/**
56 * switch_gc_head - switch the garbage collection journal head.
57 * @c: UBIFS file-system description object
58 * @buf: buffer to write
59 * @len: length of the buffer to write
60 * @lnum: LEB number written is returned here
61 * @offs: offset written is returned here
62 *
63 * This function switch the GC head to the next LEB which is reserved in
64 * @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required,
65 * and other negative error code in case of failures.
66 */
67static int switch_gc_head(struct ubifs_info *c)
68{
69 int err, gc_lnum = c->gc_lnum;
70 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
71
72 ubifs_assert(gc_lnum != -1);
73 dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)",
74 wbuf->lnum, wbuf->offs + wbuf->used, gc_lnum,
75 c->leb_size - wbuf->offs - wbuf->used);
76
77 err = ubifs_wbuf_sync_nolock(wbuf);
78 if (err)
79 return err;
80
81 /*
82 * The GC write-buffer was synchronized, we may safely unmap
83 * 'c->gc_lnum'.
84 */
85 err = ubifs_leb_unmap(c, gc_lnum);
86 if (err)
87 return err;
88
89 err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0);
90 if (err)
91 return err;
92
93 c->gc_lnum = -1;
94 err = ubifs_wbuf_seek_nolock(wbuf, gc_lnum, 0, UBI_LONGTERM);
95 return err;
96}
97
98/**
99 * move_nodes - move nodes.
100 * @c: UBIFS file-system description object
101 * @sleb: describes nodes to move
102 *
103 * This function moves valid nodes from data LEB described by @sleb to the GC
104 * journal head. The obsolete nodes are dropped.
105 *
106 * When moving nodes we have to deal with classical bin-packing problem: the
107 * space in the current GC journal head LEB and in @c->gc_lnum are the "bins",
108 * where the nodes in the @sleb->nodes list are the elements which should be
109 * fit optimally to the bins. This function uses the "first fit decreasing"
110 * strategy, although it does not really sort the nodes but just split them on
111 * 3 classes - large, medium, and small, so they are roughly sorted.
112 *
113 * This function returns zero in case of success, %-EAGAIN if commit is
114 * required, and other negative error codes in case of other failures.
115 */
116static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
117{
118 struct ubifs_scan_node *snod, *tmp;
119 struct list_head large, medium, small;
120 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
121 int avail, err, min = INT_MAX;
122
123 INIT_LIST_HEAD(&large);
124 INIT_LIST_HEAD(&medium);
125 INIT_LIST_HEAD(&small);
126
127 list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
128 struct list_head *lst;
129
130 ubifs_assert(snod->type != UBIFS_IDX_NODE);
131 ubifs_assert(snod->type != UBIFS_REF_NODE);
132 ubifs_assert(snod->type != UBIFS_CS_NODE);
133
134 err = ubifs_tnc_has_node(c, &snod->key, 0, sleb->lnum,
135 snod->offs, 0);
136 if (err < 0)
137 goto out;
138
139 lst = &snod->list;
140 list_del(lst);
141 if (!err) {
142 /* The node is obsolete, remove it from the list */
143 kfree(snod);
144 continue;
145 }
146
147 /*
148 * Sort the list of nodes so that large nodes go first, and
149 * small nodes go last.
150 */
151 if (snod->len > MEDIUM_NODE_WM)
152 list_add(lst, &large);
153 else if (snod->len > SMALL_NODE_WM)
154 list_add(lst, &medium);
155 else
156 list_add(lst, &small);
157
158 /* And find the smallest node */
159 if (snod->len < min)
160 min = snod->len;
161 }
162
163 /*
164 * Join the tree lists so that we'd have one roughly sorted list
165 * ('large' will be the head of the joined list).
166 */
167 list_splice(&medium, large.prev);
168 list_splice(&small, large.prev);
169
170 if (wbuf->lnum == -1) {
171 /*
172 * The GC journal head is not set, because it is the first GC
173 * invocation since mount.
174 */
175 err = switch_gc_head(c);
176 if (err)
177 goto out;
178 }
179
180 /* Write nodes to their new location. Use the first-fit strategy */
181 while (1) {
182 avail = c->leb_size - wbuf->offs - wbuf->used;
183 list_for_each_entry_safe(snod, tmp, &large, list) {
184 int new_lnum, new_offs;
185
186 if (avail < min)
187 break;
188
189 if (snod->len > avail)
190 /* This node does not fit */
191 continue;
192
193 cond_resched();
194
195 new_lnum = wbuf->lnum;
196 new_offs = wbuf->offs + wbuf->used;
197 err = ubifs_wbuf_write_nolock(wbuf, snod->node,
198 snod->len);
199 if (err)
200 goto out;
201 err = ubifs_tnc_replace(c, &snod->key, sleb->lnum,
202 snod->offs, new_lnum, new_offs,
203 snod->len);
204 if (err)
205 goto out;
206
207 avail = c->leb_size - wbuf->offs - wbuf->used;
208 list_del(&snod->list);
209 kfree(snod);
210 }
211
212 if (list_empty(&large))
213 break;
214
215 /*
216 * Waste the rest of the space in the LEB and switch to the
217 * next LEB.
218 */
219 err = switch_gc_head(c);
220 if (err)
221 goto out;
222 }
223
224 return 0;
225
226out:
227 list_for_each_entry_safe(snod, tmp, &large, list) {
228 list_del(&snod->list);
229 kfree(snod);
230 }
231 return err;
232}
233
234/**
235 * gc_sync_wbufs - sync write-buffers for GC.
236 * @c: UBIFS file-system description object
237 *
238 * We must guarantee that obsoleting nodes are on flash. Unfortunately they may
239 * be in a write-buffer instead. That is, a node could be written to a
240 * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is
241 * erased before the write-buffer is sync'd and then there is an unclean
242 * unmount, then an existing node is lost. To avoid this, we sync all
243 * write-buffers.
244 *
245 * This function returns %0 on success or a negative error code on failure.
246 */
247static int gc_sync_wbufs(struct ubifs_info *c)
248{
249 int err, i;
250
251 for (i = 0; i < c->jhead_cnt; i++) {
252 if (i == GCHD)
253 continue;
254 err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
255 if (err)
256 return err;
257 }
258 return 0;
259}
260
261/**
262 * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock.
263 * @c: UBIFS file-system description object
264 * @lp: describes the LEB to garbage collect
265 *
266 * This function garbage-collects an LEB and returns one of the @LEB_FREED,
267 * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is
268 * required, and other negative error codes in case of failures.
269 */
270int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
271{
272 struct ubifs_scan_leb *sleb;
273 struct ubifs_scan_node *snod;
274 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
275 int err = 0, lnum = lp->lnum;
276
277 ubifs_assert(c->gc_lnum != -1 || wbuf->offs + wbuf->used == 0 ||
278 c->need_recovery);
279 ubifs_assert(c->gc_lnum != lnum);
280 ubifs_assert(wbuf->lnum != lnum);
281
282 /*
283 * We scan the entire LEB even though we only really need to scan up to
284 * (c->leb_size - lp->free).
285 */
286 sleb = ubifs_scan(c, lnum, 0, c->sbuf);
287 if (IS_ERR(sleb))
288 return PTR_ERR(sleb);
289
290 ubifs_assert(!list_empty(&sleb->nodes));
291 snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
292
293 if (snod->type == UBIFS_IDX_NODE) {
294 struct ubifs_gced_idx_leb *idx_gc;
295
296 dbg_gc("indexing LEB %d (free %d, dirty %d)",
297 lnum, lp->free, lp->dirty);
298 list_for_each_entry(snod, &sleb->nodes, list) {
299 struct ubifs_idx_node *idx = snod->node;
300 int level = le16_to_cpu(idx->level);
301
302 ubifs_assert(snod->type == UBIFS_IDX_NODE);
303 key_read(c, ubifs_idx_key(c, idx), &snod->key);
304 err = ubifs_dirty_idx_node(c, &snod->key, level, lnum,
305 snod->offs);
306 if (err)
307 goto out;
308 }
309
310 idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
311 if (!idx_gc) {
312 err = -ENOMEM;
313 goto out;
314 }
315
316 idx_gc->lnum = lnum;
317 idx_gc->unmap = 0;
318 list_add(&idx_gc->list, &c->idx_gc);
319
320 /*
321 * Don't release the LEB until after the next commit, because
322 * it may contain date which is needed for recovery. So
323 * although we freed this LEB, it will become usable only after
324 * the commit.
325 */
326 err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0,
327 LPROPS_INDEX, 1);
328 if (err)
329 goto out;
330 err = LEB_FREED_IDX;
331 } else {
332 dbg_gc("data LEB %d (free %d, dirty %d)",
333 lnum, lp->free, lp->dirty);
334
335 err = move_nodes(c, sleb);
336 if (err)
337 goto out;
338
339 err = gc_sync_wbufs(c);
340 if (err)
341 goto out;
342
343 err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);
344 if (err)
345 goto out;
346
347 if (c->gc_lnum == -1) {
348 c->gc_lnum = lnum;
349 err = LEB_RETAINED;
350 } else {
351 err = ubifs_wbuf_sync_nolock(wbuf);
352 if (err)
353 goto out;
354
355 err = ubifs_leb_unmap(c, lnum);
356 if (err)
357 goto out;
358
359 err = LEB_FREED;
360 }
361 }
362
363out:
364 ubifs_scan_destroy(sleb);
365 return err;
366}
367
368/**
369 * ubifs_garbage_collect - UBIFS garbage collector.
370 * @c: UBIFS file-system description object
371 * @anyway: do GC even if there are free LEBs
372 *
373 * This function does out-of-place garbage collection. The return codes are:
374 * o positive LEB number if the LEB has been freed and may be used;
375 * o %-EAGAIN if the caller has to run commit;
376 * o %-ENOSPC if GC failed to make any progress;
377 * o other negative error codes in case of other errors.
378 *
379 * Garbage collector writes data to the journal when GC'ing data LEBs, and just
380 * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point
381 * commit may be required. But commit cannot be run from inside GC, because the
382 * caller might be holding the commit lock, so %-EAGAIN is returned instead;
383 * And this error code means that the caller has to run commit, and re-run GC
384 * if there is still no free space.
385 *
386 * There are many reasons why this function may return %-EAGAIN:
387 * o the log is full and there is no space to write an LEB reference for
388 * @c->gc_lnum;
389 * o the journal is too large and exceeds size limitations;
390 * o GC moved indexing LEBs, but they can be used only after the commit;
391 * o the shrinker fails to find clean znodes to free and requests the commit;
392 * o etc.
393 *
394 * Note, if the file-system is close to be full, this function may return
395 * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of
396 * the function. E.g., this happens if the limits on the journal size are too
397 * tough and GC writes too much to the journal before an LEB is freed. This
398 * might also mean that the journal is too large, and the TNC becomes to big,
399 * so that the shrinker is constantly called, finds not clean znodes to free,
400 * and requests commit. Well, this may also happen if the journal is all right,
401 * but another kernel process consumes too much memory. Anyway, infinite
402 * %-EAGAIN may happen, but in some extreme/misconfiguration cases.
403 */
404int ubifs_garbage_collect(struct ubifs_info *c, int anyway)
405{
406 int i, err, ret, min_space = c->dead_wm;
407 struct ubifs_lprops lp;
408 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
409
410 ubifs_assert_cmt_locked(c);
411
412 if (ubifs_gc_should_commit(c))
413 return -EAGAIN;
414
415 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
416
417 if (c->ro_media) {
418 ret = -EROFS;
419 goto out_unlock;
420 }
421
422 /* We expect the write-buffer to be empty on entry */
423 ubifs_assert(!wbuf->used);
424
425 for (i = 0; ; i++) {
426 int space_before = c->leb_size - wbuf->offs - wbuf->used;
427 int space_after;
428
429 cond_resched();
430
431 /* Give the commit an opportunity to run */
432 if (ubifs_gc_should_commit(c)) {
433 ret = -EAGAIN;
434 break;
435 }
436
437 if (i > SOFT_LEBS_LIMIT && !list_empty(&c->idx_gc)) {
438 /*
439 * We've done enough iterations. Indexing LEBs were
440 * moved and will be available after the commit.
441 */
442 dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN");
443 ubifs_commit_required(c);
444 ret = -EAGAIN;
445 break;
446 }
447
448 if (i > HARD_LEBS_LIMIT) {
449 /*
450 * We've moved too many LEBs and have not made
451 * progress, give up.
452 */
453 dbg_gc("hard limit, -ENOSPC");
454 ret = -ENOSPC;
455 break;
456 }
457
458 /*
459 * Empty and freeable LEBs can turn up while we waited for
460 * the wbuf lock, or while we have been running GC. In that
461 * case, we should just return one of those instead of
462 * continuing to GC dirty LEBs. Hence we request
463 * 'ubifs_find_dirty_leb()' to return an empty LEB if it can.
464 */
465 ret = ubifs_find_dirty_leb(c, &lp, min_space, anyway ? 0 : 1);
466 if (ret) {
467 if (ret == -ENOSPC)
468 dbg_gc("no more dirty LEBs");
469 break;
470 }
471
472 dbg_gc("found LEB %d: free %d, dirty %d, sum %d "
473 "(min. space %d)", lp.lnum, lp.free, lp.dirty,
474 lp.free + lp.dirty, min_space);
475
476 if (lp.free + lp.dirty == c->leb_size) {
477 /* An empty LEB was returned */
478 dbg_gc("LEB %d is free, return it", lp.lnum);
479 /*
480 * ubifs_find_dirty_leb() doesn't return freeable index
481 * LEBs.
482 */
483 ubifs_assert(!(lp.flags & LPROPS_INDEX));
484 if (lp.free != c->leb_size) {
485 /*
486 * Write buffers must be sync'd before
487 * unmapping freeable LEBs, because one of them
488 * may contain data which obsoletes something
489 * in 'lp.pnum'.
490 */
491 ret = gc_sync_wbufs(c);
492 if (ret)
493 goto out;
494 ret = ubifs_change_one_lp(c, lp.lnum,
495 c->leb_size, 0, 0, 0,
496 0);
497 if (ret)
498 goto out;
499 }
500 ret = ubifs_leb_unmap(c, lp.lnum);
501 if (ret)
502 goto out;
503 ret = lp.lnum;
504 break;
505 }
506
507 space_before = c->leb_size - wbuf->offs - wbuf->used;
508 if (wbuf->lnum == -1)
509 space_before = 0;
510
511 ret = ubifs_garbage_collect_leb(c, &lp);
512 if (ret < 0) {
513 if (ret == -EAGAIN || ret == -ENOSPC) {
514 /*
515 * These codes are not errors, so we have to
516 * return the LEB to lprops. But if the
517 * 'ubifs_return_leb()' function fails, its
518 * failure code is propagated to the caller
519 * instead of the original '-EAGAIN' or
520 * '-ENOSPC'.
521 */
522 err = ubifs_return_leb(c, lp.lnum);
523 if (err)
524 ret = err;
525 break;
526 }
527 goto out;
528 }
529
530 if (ret == LEB_FREED) {
531 /* An LEB has been freed and is ready for use */
532 dbg_gc("LEB %d freed, return", lp.lnum);
533 ret = lp.lnum;
534 break;
535 }
536
537 if (ret == LEB_FREED_IDX) {
538 /*
539 * This was an indexing LEB and it cannot be
540 * immediately used. And instead of requesting the
541 * commit straight away, we try to garbage collect some
542 * more.
543 */
544 dbg_gc("indexing LEB %d freed, continue", lp.lnum);
545 continue;
546 }
547
548 ubifs_assert(ret == LEB_RETAINED);
549 space_after = c->leb_size - wbuf->offs - wbuf->used;
550 dbg_gc("LEB %d retained, freed %d bytes", lp.lnum,
551 space_after - space_before);
552
553 if (space_after > space_before) {
554 /* GC makes progress, keep working */
555 min_space >>= 1;
556 if (min_space < c->dead_wm)
557 min_space = c->dead_wm;
558 continue;
559 }
560
561 dbg_gc("did not make progress");
562
563 /*
564 * GC moved an LEB bud have not done any progress. This means
565 * that the previous GC head LEB contained too few free space
566 * and the LEB which was GC'ed contained only large nodes which
567 * did not fit that space.
568 *
569 * We can do 2 things:
570 * 1. pick another LEB in a hope it'll contain a small node
571 * which will fit the space we have at the end of current GC
572 * head LEB, but there is no guarantee, so we try this out
573 * unless we have already been working for too long;
574 * 2. request an LEB with more dirty space, which will force
575 * 'ubifs_find_dirty_leb()' to start scanning the lprops
576 * table, instead of just picking one from the heap
577 * (previously it already picked the dirtiest LEB).
578 */
579 if (i < SOFT_LEBS_LIMIT) {
580 dbg_gc("try again");
581 continue;
582 }
583
584 min_space <<= 1;
585 if (min_space > c->dark_wm)
586 min_space = c->dark_wm;
587 dbg_gc("set min. space to %d", min_space);
588 }
589
590 if (ret == -ENOSPC && !list_empty(&c->idx_gc)) {
591 dbg_gc("no space, some index LEBs GC'ed, -EAGAIN");
592 ubifs_commit_required(c);
593 ret = -EAGAIN;
594 }
595
596 err = ubifs_wbuf_sync_nolock(wbuf);
597 if (!err)
598 err = ubifs_leb_unmap(c, c->gc_lnum);
599 if (err) {
600 ret = err;
601 goto out;
602 }
603out_unlock:
604 mutex_unlock(&wbuf->io_mutex);
605 return ret;
606
607out:
608 ubifs_assert(ret < 0);
609 ubifs_assert(ret != -ENOSPC && ret != -EAGAIN);
610 ubifs_ro_mode(c, ret);
611 ubifs_wbuf_sync_nolock(wbuf);
612 mutex_unlock(&wbuf->io_mutex);
613 ubifs_return_leb(c, lp.lnum);
614 return ret;
615}
616
617/**
618 * ubifs_gc_start_commit - garbage collection at start of commit.
619 * @c: UBIFS file-system description object
620 *
621 * If a LEB has only dirty and free space, then we may safely unmap it and make
622 * it free. Note, we cannot do this with indexing LEBs because dirty space may
623 * correspond index nodes that are required for recovery. In that case, the
624 * LEB cannot be unmapped until after the next commit.
625 *
626 * This function returns %0 upon success and a negative error code upon failure.
627 */
628int ubifs_gc_start_commit(struct ubifs_info *c)
629{
630 struct ubifs_gced_idx_leb *idx_gc;
631 const struct ubifs_lprops *lp;
632 int err = 0, flags;
633
634 ubifs_get_lprops(c);
635
636 /*
637 * Unmap (non-index) freeable LEBs. Note that recovery requires that all
638 * wbufs are sync'd before this, which is done in 'do_commit()'.
639 */
640 while (1) {
641 lp = ubifs_fast_find_freeable(c);
642 if (unlikely(IS_ERR(lp))) {
643 err = PTR_ERR(lp);
644 goto out;
645 }
646 if (!lp)
647 break;
648 ubifs_assert(!(lp->flags & LPROPS_TAKEN));
649 ubifs_assert(!(lp->flags & LPROPS_INDEX));
650 err = ubifs_leb_unmap(c, lp->lnum);
651 if (err)
652 goto out;
653 lp = ubifs_change_lp(c, lp, c->leb_size, 0, lp->flags, 0);
654 if (unlikely(IS_ERR(lp))) {
655 err = PTR_ERR(lp);
656 goto out;
657 }
658 ubifs_assert(!(lp->flags & LPROPS_TAKEN));
659 ubifs_assert(!(lp->flags & LPROPS_INDEX));
660 }
661
662 /* Mark GC'd index LEBs OK to unmap after this commit finishes */
663 list_for_each_entry(idx_gc, &c->idx_gc, list)
664 idx_gc->unmap = 1;
665
666 /* Record index freeable LEBs for unmapping after commit */
667 while (1) {
668 lp = ubifs_fast_find_frdi_idx(c);
669 if (unlikely(IS_ERR(lp))) {
670 err = PTR_ERR(lp);
671 goto out;
672 }
673 if (!lp)
674 break;
675 idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
676 if (!idx_gc) {
677 err = -ENOMEM;
678 goto out;
679 }
680 ubifs_assert(!(lp->flags & LPROPS_TAKEN));
681 ubifs_assert(lp->flags & LPROPS_INDEX);
682 /* Don't release the LEB until after the next commit */
683 flags = (lp->flags | LPROPS_TAKEN) ^ LPROPS_INDEX;
684 lp = ubifs_change_lp(c, lp, c->leb_size, 0, flags, 1);
685 if (unlikely(IS_ERR(lp))) {
686 err = PTR_ERR(lp);
687 kfree(idx_gc);
688 goto out;
689 }
690 ubifs_assert(lp->flags & LPROPS_TAKEN);
691 ubifs_assert(!(lp->flags & LPROPS_INDEX));
692 idx_gc->lnum = lp->lnum;
693 idx_gc->unmap = 1;
694 list_add(&idx_gc->list, &c->idx_gc);
695 }
696out:
697 ubifs_release_lprops(c);
698 return err;
699}
700
701/**
702 * ubifs_gc_end_commit - garbage collection at end of commit.
703 * @c: UBIFS file-system description object
704 *
705 * This function completes out-of-place garbage collection of index LEBs.
706 */
707int ubifs_gc_end_commit(struct ubifs_info *c)
708{
709 struct ubifs_gced_idx_leb *idx_gc, *tmp;
710 struct ubifs_wbuf *wbuf;
711 int err = 0;
712
713 wbuf = &c->jheads[GCHD].wbuf;
714 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
715 list_for_each_entry_safe(idx_gc, tmp, &c->idx_gc, list)
716 if (idx_gc->unmap) {
717 dbg_gc("LEB %d", idx_gc->lnum);
718 err = ubifs_leb_unmap(c, idx_gc->lnum);
719 if (err)
720 goto out;
721 err = ubifs_change_one_lp(c, idx_gc->lnum, LPROPS_NC,
722 LPROPS_NC, 0, LPROPS_TAKEN, -1);
723 if (err)
724 goto out;
725 list_del(&idx_gc->list);
726 kfree(idx_gc);
727 }
728out:
729 mutex_unlock(&wbuf->io_mutex);
730 return err;
731}
732
733/**
734 * ubifs_destroy_idx_gc - destroy idx_gc list.
735 * @c: UBIFS file-system description object
736 *
737 * This function destroys the idx_gc list. It is called when unmounting or
738 * remounting read-only so locks are not needed.
739 */
740void ubifs_destroy_idx_gc(struct ubifs_info *c)
741{
742 while (!list_empty(&c->idx_gc)) {
743 struct ubifs_gced_idx_leb *idx_gc;
744
745 idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb,
746 list);
747 c->idx_gc_cnt -= 1;
748 list_del(&idx_gc->list);
749 kfree(idx_gc);
750 }
751
752}
753
754/**
755 * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list.
756 * @c: UBIFS file-system description object
757 *
758 * Called during start commit so locks are not needed.
759 */
760int ubifs_get_idx_gc_leb(struct ubifs_info *c)
761{
762 struct ubifs_gced_idx_leb *idx_gc;
763 int lnum;
764
765 if (list_empty(&c->idx_gc))
766 return -ENOSPC;
767 idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb, list);
768 lnum = idx_gc->lnum;
769 /* c->idx_gc_cnt is updated by the caller when lprops are updated */
770 list_del(&idx_gc->list);
771 kfree(idx_gc);
772 return lnum;
773}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-06 12:47:45 -0500