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: Artem Bityutskiy (Битюцкий Артём)
24 * This file contains functions for finding LEBs for various purposes e.g.
25 * garbage collection. In general, lprops category heaps and lists are used
26 * for fast access, falling back on scanning the LPT as a last resort.
29 #include <linux/sort.h>
33 * struct scan_data - data provided to scan callback functions
34 * @min_space: minimum number of bytes for which to scan
35 * @pick_free: whether it is OK to scan for empty LEBs
36 * @lnum: LEB number found is returned here
37 * @exclude_index: whether to exclude index LEBs
47 * valuable - determine whether LEB properties are valuable.
48 * @c: the UBIFS file-system description object
49 * @lprops: LEB properties
51 * This function return %1 if the LEB properties should be added to the LEB
52 * properties tree in memory. Otherwise %0 is returned.
54 static int valuable(struct ubifs_info *c, const struct ubifs_lprops *lprops)
56 int n, cat = lprops->flags & LPROPS_CAT_MASK;
57 struct ubifs_lpt_heap *heap;
61 case LPROPS_DIRTY_IDX:
63 heap = &c->lpt_heap[cat - 1];
64 if (heap->cnt < heap->max_cnt)
66 if (lprops->free + lprops->dirty >= c->dark_wm)
70 n = c->lst.empty_lebs + c->freeable_cnt -
71 c->lst.taken_empty_lebs;
84 * scan_for_dirty_cb - dirty space scan callback.
85 * @c: the UBIFS file-system description object
86 * @lprops: LEB properties to scan
87 * @in_tree: whether the LEB properties are in main memory
88 * @data: information passed to and from the caller of the scan
90 * This function returns a code that indicates whether the scan should continue
91 * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
92 * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
95 static int scan_for_dirty_cb(struct ubifs_info *c,
96 const struct ubifs_lprops *lprops, int in_tree,
97 struct scan_data *data)
99 int ret = LPT_SCAN_CONTINUE;
101 /* Exclude LEBs that are currently in use */
102 if (lprops->flags & LPROPS_TAKEN)
103 return LPT_SCAN_CONTINUE;
104 /* Determine whether to add these LEB properties to the tree */
105 if (!in_tree && valuable(c, lprops))
107 /* Exclude LEBs with too little space */
108 if (lprops->free + lprops->dirty < data->min_space)
110 /* If specified, exclude index LEBs */
111 if (data->exclude_index && lprops->flags & LPROPS_INDEX)
113 /* If specified, exclude empty or freeable LEBs */
114 if (lprops->free + lprops->dirty == c->leb_size) {
115 if (!data->pick_free)
117 /* Exclude LEBs with too little dirty space (unless it is empty) */
118 } else if (lprops->dirty < c->dead_wm)
120 /* Finally we found space */
121 data->lnum = lprops->lnum;
122 return LPT_SCAN_ADD | LPT_SCAN_STOP;
126 * scan_for_dirty - find a data LEB with free space.
127 * @c: the UBIFS file-system description object
128 * @min_space: minimum amount free plus dirty space the returned LEB has to
130 * @pick_free: if it is OK to return a free or freeable LEB
131 * @exclude_index: whether to exclude index LEBs
133 * This function returns a pointer to the LEB properties found or a negative
136 static const struct ubifs_lprops *scan_for_dirty(struct ubifs_info *c,
137 int min_space, int pick_free,
140 const struct ubifs_lprops *lprops;
141 struct ubifs_lpt_heap *heap;
142 struct scan_data data;
145 /* There may be an LEB with enough dirty space on the free heap */
146 heap = &c->lpt_heap[LPROPS_FREE - 1];
147 for (i = 0; i < heap->cnt; i++) {
148 lprops = heap->arr[i];
149 if (lprops->free + lprops->dirty < min_space)
151 if (lprops->dirty < c->dead_wm)
156 * A LEB may have fallen off of the bottom of the dirty heap, and ended
157 * up as uncategorized even though it has enough dirty space for us now,
158 * so check the uncategorized list. N.B. neither empty nor freeable LEBs
159 * can end up as uncategorized because they are kept on lists not
160 * finite-sized heaps.
162 list_for_each_entry(lprops, &c->uncat_list, list) {
163 if (lprops->flags & LPROPS_TAKEN)
165 if (lprops->free + lprops->dirty < min_space)
167 if (exclude_index && (lprops->flags & LPROPS_INDEX))
169 if (lprops->dirty < c->dead_wm)
173 /* We have looked everywhere in main memory, now scan the flash */
174 if (c->pnodes_have >= c->pnode_cnt)
175 /* All pnodes are in memory, so skip scan */
176 return ERR_PTR(-ENOSPC);
177 data.min_space = min_space;
178 data.pick_free = pick_free;
180 data.exclude_index = exclude_index;
181 err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
182 (ubifs_lpt_scan_callback)scan_for_dirty_cb,
186 ubifs_assert(data.lnum >= c->main_first && data.lnum < c->leb_cnt);
187 c->lscan_lnum = data.lnum;
188 lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
191 ubifs_assert(lprops->lnum == data.lnum);
192 ubifs_assert(lprops->free + lprops->dirty >= min_space);
193 ubifs_assert(lprops->dirty >= c->dead_wm ||
195 lprops->free + lprops->dirty == c->leb_size));
196 ubifs_assert(!(lprops->flags & LPROPS_TAKEN));
197 ubifs_assert(!exclude_index || !(lprops->flags & LPROPS_INDEX));
202 * ubifs_find_dirty_leb - find a dirty LEB for the Garbage Collector.
203 * @c: the UBIFS file-system description object
204 * @ret_lp: LEB properties are returned here on exit
205 * @min_space: minimum amount free plus dirty space the returned LEB has to
207 * @pick_free: controls whether it is OK to pick empty or index LEBs
209 * This function tries to find a dirty logical eraseblock which has at least
210 * @min_space free and dirty space. It prefers to take an LEB from the dirty or
211 * dirty index heap, and it falls-back to LPT scanning if the heaps are empty
212 * or do not have an LEB which satisfies the @min_space criteria.
214 * Note, LEBs which have less than dead watermark of free + dirty space are
215 * never picked by this function.
217 * The additional @pick_free argument controls if this function has to return a
218 * free or freeable LEB if one is present. For example, GC must to set it to %1,
219 * when called from the journal space reservation function, because the
220 * appearance of free space may coincide with the loss of enough dirty space
221 * for GC to succeed anyway.
223 * In contrast, if the Garbage Collector is called from budgeting, it should
224 * just make free space, not return LEBs which are already free or freeable.
226 * In addition @pick_free is set to %2 by the recovery process in order to
227 * recover gc_lnum in which case an index LEB must not be returned.
229 * This function returns zero and the LEB properties of found dirty LEB in case
230 * of success, %-ENOSPC if no dirty LEB was found and a negative error code in
231 * case of other failures. The returned LEB is marked as "taken".
233 int ubifs_find_dirty_leb(struct ubifs_info *c, struct ubifs_lprops *ret_lp,
234 int min_space, int pick_free)
236 int err = 0, sum, exclude_index = pick_free == 2 ? 1 : 0;
237 const struct ubifs_lprops *lp = NULL, *idx_lp = NULL;
238 struct ubifs_lpt_heap *heap, *idx_heap;
243 int lebs, rsvd_idx_lebs = 0;
245 spin_lock(&c->space_lock);
246 lebs = c->lst.empty_lebs + c->idx_gc_cnt;
247 lebs += c->freeable_cnt - c->lst.taken_empty_lebs;
250 * Note, the index may consume more LEBs than have been reserved
251 * for it. It is OK because it might be consolidated by GC.
252 * But if the index takes fewer LEBs than it is reserved for it,
253 * this function must avoid picking those reserved LEBs.
255 if (c->min_idx_lebs >= c->lst.idx_lebs) {
256 rsvd_idx_lebs = c->min_idx_lebs - c->lst.idx_lebs;
259 spin_unlock(&c->space_lock);
261 /* Check if there are enough free LEBs for the index */
262 if (rsvd_idx_lebs < lebs) {
263 /* OK, try to find an empty LEB */
264 lp = ubifs_fast_find_empty(c);
268 /* Or a freeable LEB */
269 lp = ubifs_fast_find_freeable(c);
274 * We cannot pick free/freeable LEBs in the below code.
278 spin_lock(&c->space_lock);
279 exclude_index = (c->min_idx_lebs >= c->lst.idx_lebs);
280 spin_unlock(&c->space_lock);
283 /* Look on the dirty and dirty index heaps */
284 heap = &c->lpt_heap[LPROPS_DIRTY - 1];
285 idx_heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
287 if (idx_heap->cnt && !exclude_index) {
288 idx_lp = idx_heap->arr[0];
289 sum = idx_lp->free + idx_lp->dirty;
291 * Since we reserve thrice as much space for the index than it
292 * actually takes, it does not make sense to pick indexing LEBs
293 * with less than, say, half LEB of dirty space. May be half is
294 * not the optimal boundary - this should be tested and
295 * checked. This boundary should determine how much we use
296 * in-the-gaps to consolidate the index comparing to how much
297 * we use garbage collector to consolidate it. The "half"
298 * criteria just feels to be fine.
300 if (sum < min_space || sum < c->half_leb_size)
306 if (lp->dirty + lp->free < min_space)
310 /* Pick the LEB with most space */
312 if (idx_lp->free + idx_lp->dirty >= lp->free + lp->dirty)
314 } else if (idx_lp && !lp)
318 ubifs_assert(lp->free + lp->dirty >= c->dead_wm);
322 /* Did not find a dirty LEB on the dirty heaps, have to scan */
323 dbg_find("scanning LPT for a dirty LEB");
324 lp = scan_for_dirty(c, min_space, pick_free, exclude_index);
329 ubifs_assert(lp->dirty >= c->dead_wm ||
330 (pick_free && lp->free + lp->dirty == c->leb_size));
333 dbg_find("found LEB %d, free %d, dirty %d, flags %#x",
334 lp->lnum, lp->free, lp->dirty, lp->flags);
336 lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
337 lp->flags | LPROPS_TAKEN, 0);
343 memcpy(ret_lp, lp, sizeof(struct ubifs_lprops));
346 ubifs_release_lprops(c);
351 * scan_for_free_cb - free space scan callback.
352 * @c: the UBIFS file-system description object
353 * @lprops: LEB properties to scan
354 * @in_tree: whether the LEB properties are in main memory
355 * @data: information passed to and from the caller of the scan
357 * This function returns a code that indicates whether the scan should continue
358 * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
359 * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
362 static int scan_for_free_cb(struct ubifs_info *c,
363 const struct ubifs_lprops *lprops, int in_tree,
364 struct scan_data *data)
366 int ret = LPT_SCAN_CONTINUE;
368 /* Exclude LEBs that are currently in use */
369 if (lprops->flags & LPROPS_TAKEN)
370 return LPT_SCAN_CONTINUE;
371 /* Determine whether to add these LEB properties to the tree */
372 if (!in_tree && valuable(c, lprops))
374 /* Exclude index LEBs */
375 if (lprops->flags & LPROPS_INDEX)
377 /* Exclude LEBs with too little space */
378 if (lprops->free < data->min_space)
380 /* If specified, exclude empty LEBs */
381 if (!data->pick_free && lprops->free == c->leb_size)
384 * LEBs that have only free and dirty space must not be allocated
385 * because they may have been unmapped already or they may have data
386 * that is obsolete only because of nodes that are still sitting in a
389 if (lprops->free + lprops->dirty == c->leb_size && lprops->dirty > 0)
391 /* Finally we found space */
392 data->lnum = lprops->lnum;
393 return LPT_SCAN_ADD | LPT_SCAN_STOP;
397 * do_find_free_space - find a data LEB with free space.
398 * @c: the UBIFS file-system description object
399 * @min_space: minimum amount of free space required
400 * @pick_free: whether it is OK to scan for empty LEBs
401 * @squeeze: whether to try to find space in a non-empty LEB first
403 * This function returns a pointer to the LEB properties found or a negative
407 const struct ubifs_lprops *do_find_free_space(struct ubifs_info *c,
408 int min_space, int pick_free,
411 const struct ubifs_lprops *lprops;
412 struct ubifs_lpt_heap *heap;
413 struct scan_data data;
417 lprops = ubifs_fast_find_free(c);
418 if (lprops && lprops->free >= min_space)
422 lprops = ubifs_fast_find_empty(c);
427 lprops = ubifs_fast_find_free(c);
428 if (lprops && lprops->free >= min_space)
431 /* There may be an LEB with enough free space on the dirty heap */
432 heap = &c->lpt_heap[LPROPS_DIRTY - 1];
433 for (i = 0; i < heap->cnt; i++) {
434 lprops = heap->arr[i];
435 if (lprops->free >= min_space)
439 * A LEB may have fallen off of the bottom of the free heap, and ended
440 * up as uncategorized even though it has enough free space for us now,
441 * so check the uncategorized list. N.B. neither empty nor freeable LEBs
442 * can end up as uncategorized because they are kept on lists not
443 * finite-sized heaps.
445 list_for_each_entry(lprops, &c->uncat_list, list) {
446 if (lprops->flags & LPROPS_TAKEN)
448 if (lprops->flags & LPROPS_INDEX)
450 if (lprops->free >= min_space)
453 /* We have looked everywhere in main memory, now scan the flash */
454 if (c->pnodes_have >= c->pnode_cnt)
455 /* All pnodes are in memory, so skip scan */
456 return ERR_PTR(-ENOSPC);
457 data.min_space = min_space;
458 data.pick_free = pick_free;
460 err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
461 (ubifs_lpt_scan_callback)scan_for_free_cb,
465 ubifs_assert(data.lnum >= c->main_first && data.lnum < c->leb_cnt);
466 c->lscan_lnum = data.lnum;
467 lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
470 ubifs_assert(lprops->lnum == data.lnum);
471 ubifs_assert(lprops->free >= min_space);
472 ubifs_assert(!(lprops->flags & LPROPS_TAKEN));
473 ubifs_assert(!(lprops->flags & LPROPS_INDEX));
478 * ubifs_find_free_space - find a data LEB with free space.
479 * @c: the UBIFS file-system description object
480 * @min_space: minimum amount of required free space
481 * @offs: contains offset of where free space starts on exit
482 * @squeeze: whether to try to find space in a non-empty LEB first
484 * This function looks for an LEB with at least @min_space bytes of free space.
485 * It tries to find an empty LEB if possible. If no empty LEBs are available,
486 * this function searches for a non-empty data LEB. The returned LEB is marked
489 * This function returns found LEB number in case of success, %-ENOSPC if it
490 * failed to find a LEB with @min_space bytes of free space and other a negative
491 * error codes in case of failure.
493 int ubifs_find_free_space(struct ubifs_info *c, int min_space, int *offs,
496 const struct ubifs_lprops *lprops;
497 int lebs, rsvd_idx_lebs, pick_free = 0, err, lnum, flags;
499 dbg_find("min_space %d", min_space);
502 /* Check if there are enough empty LEBs for commit */
503 spin_lock(&c->space_lock);
504 if (c->min_idx_lebs > c->lst.idx_lebs)
505 rsvd_idx_lebs = c->min_idx_lebs - c->lst.idx_lebs;
508 lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
509 c->lst.taken_empty_lebs;
510 if (rsvd_idx_lebs < lebs)
512 * OK to allocate an empty LEB, but we still don't want to go
513 * looking for one if there aren't any.
515 if (c->lst.empty_lebs - c->lst.taken_empty_lebs > 0) {
518 * Because we release the space lock, we must account
519 * for this allocation here. After the LEB properties
520 * flags have been updated, we subtract one. Note, the
521 * result of this is that lprops also decreases
522 * @taken_empty_lebs in 'ubifs_change_lp()', so it is
523 * off by one for a short period of time which may
524 * introduce a small disturbance to budgeting
525 * calculations, but this is harmless because at the
526 * worst case this would make the budgeting subsystem
527 * be more pessimistic than needed.
529 * Fundamentally, this is about serialization of the
530 * budgeting and lprops subsystems. We could make the
531 * @space_lock a mutex and avoid dropping it before
532 * calling 'ubifs_change_lp()', but mutex is more
533 * heavy-weight, and we want budgeting to be as fast as
536 c->lst.taken_empty_lebs += 1;
538 spin_unlock(&c->space_lock);
540 lprops = do_find_free_space(c, min_space, pick_free, squeeze);
541 if (IS_ERR(lprops)) {
542 err = PTR_ERR(lprops);
547 flags = lprops->flags | LPROPS_TAKEN;
549 lprops = ubifs_change_lp(c, lprops, LPROPS_NC, LPROPS_NC, flags, 0);
550 if (IS_ERR(lprops)) {
551 err = PTR_ERR(lprops);
556 spin_lock(&c->space_lock);
557 c->lst.taken_empty_lebs -= 1;
558 spin_unlock(&c->space_lock);
561 *offs = c->leb_size - lprops->free;
562 ubifs_release_lprops(c);
566 * Ensure that empty LEBs have been unmapped. They may not have
567 * been, for example, because of an unclean unmount. Also
568 * LEBs that were freeable LEBs (free + dirty == leb_size) will
569 * not have been unmapped.
571 err = ubifs_leb_unmap(c, lnum);
576 dbg_find("found LEB %d, free %d", lnum, c->leb_size - *offs);
577 ubifs_assert(*offs <= c->leb_size - min_space);
582 spin_lock(&c->space_lock);
583 c->lst.taken_empty_lebs -= 1;
584 spin_unlock(&c->space_lock);
586 ubifs_release_lprops(c);
591 * scan_for_idx_cb - callback used by the scan for a free LEB for the index.
592 * @c: the UBIFS file-system description object
593 * @lprops: LEB properties to scan
594 * @in_tree: whether the LEB properties are in main memory
595 * @data: information passed to and from the caller of the scan
597 * This function returns a code that indicates whether the scan should continue
598 * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
599 * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
602 static int scan_for_idx_cb(struct ubifs_info *c,
603 const struct ubifs_lprops *lprops, int in_tree,
604 struct scan_data *data)
606 int ret = LPT_SCAN_CONTINUE;
608 /* Exclude LEBs that are currently in use */
609 if (lprops->flags & LPROPS_TAKEN)
610 return LPT_SCAN_CONTINUE;
611 /* Determine whether to add these LEB properties to the tree */
612 if (!in_tree && valuable(c, lprops))
614 /* Exclude index LEBS */
615 if (lprops->flags & LPROPS_INDEX)
617 /* Exclude LEBs that cannot be made empty */
618 if (lprops->free + lprops->dirty != c->leb_size)
621 * We are allocating for the index so it is safe to allocate LEBs with
622 * only free and dirty space, because write buffers are sync'd at commit
625 data->lnum = lprops->lnum;
626 return LPT_SCAN_ADD | LPT_SCAN_STOP;
630 * scan_for_leb_for_idx - scan for a free LEB for the index.
631 * @c: the UBIFS file-system description object
633 static const struct ubifs_lprops *scan_for_leb_for_idx(struct ubifs_info *c)
635 struct ubifs_lprops *lprops;
636 struct scan_data data;
640 err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
641 (ubifs_lpt_scan_callback)scan_for_idx_cb,
645 ubifs_assert(data.lnum >= c->main_first && data.lnum < c->leb_cnt);
646 c->lscan_lnum = data.lnum;
647 lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
650 ubifs_assert(lprops->lnum == data.lnum);
651 ubifs_assert(lprops->free + lprops->dirty == c->leb_size);
652 ubifs_assert(!(lprops->flags & LPROPS_TAKEN));
653 ubifs_assert(!(lprops->flags & LPROPS_INDEX));
658 * ubifs_find_free_leb_for_idx - find a free LEB for the index.
659 * @c: the UBIFS file-system description object
661 * This function looks for a free LEB and returns that LEB number. The returned
662 * LEB is marked as "taken", "index".
664 * Only empty LEBs are allocated. This is for two reasons. First, the commit
665 * calculates the number of LEBs to allocate based on the assumption that they
666 * will be empty. Secondly, free space at the end of an index LEB is not
667 * guaranteed to be empty because it may have been used by the in-the-gaps
668 * method prior to an unclean unmount.
670 * If no LEB is found %-ENOSPC is returned. For other failures another negative
671 * error code is returned.
673 int ubifs_find_free_leb_for_idx(struct ubifs_info *c)
675 const struct ubifs_lprops *lprops;
676 int lnum = -1, err, flags;
680 lprops = ubifs_fast_find_empty(c);
682 lprops = ubifs_fast_find_freeable(c);
684 ubifs_assert(c->freeable_cnt == 0);
685 if (c->lst.empty_lebs - c->lst.taken_empty_lebs > 0) {
686 lprops = scan_for_leb_for_idx(c);
687 if (IS_ERR(lprops)) {
688 err = PTR_ERR(lprops);
702 dbg_find("found LEB %d, free %d, dirty %d, flags %#x",
703 lnum, lprops->free, lprops->dirty, lprops->flags);
705 flags = lprops->flags | LPROPS_TAKEN | LPROPS_INDEX;
706 lprops = ubifs_change_lp(c, lprops, c->leb_size, 0, flags, 0);
707 if (IS_ERR(lprops)) {
708 err = PTR_ERR(lprops);
712 ubifs_release_lprops(c);
715 * Ensure that empty LEBs have been unmapped. They may not have been,
716 * for example, because of an unclean unmount. Also LEBs that were
717 * freeable LEBs (free + dirty == leb_size) will not have been unmapped.
719 err = ubifs_leb_unmap(c, lnum);
721 ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
722 LPROPS_TAKEN | LPROPS_INDEX, 0);
729 ubifs_release_lprops(c);
733 static int cmp_dirty_idx(const struct ubifs_lprops **a,
734 const struct ubifs_lprops **b)
736 const struct ubifs_lprops *lpa = *a;
737 const struct ubifs_lprops *lpb = *b;
739 return lpa->dirty + lpa->free - lpb->dirty - lpb->free;
742 static void swap_dirty_idx(struct ubifs_lprops **a, struct ubifs_lprops **b,
745 struct ubifs_lprops *t = *a;
752 * ubifs_save_dirty_idx_lnums - save an array of the most dirty index LEB nos.
753 * @c: the UBIFS file-system description object
755 * This function is called each commit to create an array of LEB numbers of
756 * dirty index LEBs sorted in order of dirty and free space. This is used by
757 * the in-the-gaps method of TNC commit.
759 int ubifs_save_dirty_idx_lnums(struct ubifs_info *c)
764 /* Copy the LPROPS_DIRTY_IDX heap */
765 c->dirty_idx.cnt = c->lpt_heap[LPROPS_DIRTY_IDX - 1].cnt;
766 memcpy(c->dirty_idx.arr, c->lpt_heap[LPROPS_DIRTY_IDX - 1].arr,
767 sizeof(void *) * c->dirty_idx.cnt);
768 /* Sort it so that the dirtiest is now at the end */
769 sort(c->dirty_idx.arr, c->dirty_idx.cnt, sizeof(void *),
770 (int (*)(const void *, const void *))cmp_dirty_idx,
771 (void (*)(void *, void *, int))swap_dirty_idx);
772 dbg_find("found %d dirty index LEBs", c->dirty_idx.cnt);
773 if (c->dirty_idx.cnt)
774 dbg_find("dirtiest index LEB is %d with dirty %d and free %d",
775 c->dirty_idx.arr[c->dirty_idx.cnt - 1]->lnum,
776 c->dirty_idx.arr[c->dirty_idx.cnt - 1]->dirty,
777 c->dirty_idx.arr[c->dirty_idx.cnt - 1]->free);
778 /* Replace the lprops pointers with LEB numbers */
779 for (i = 0; i < c->dirty_idx.cnt; i++)
780 c->dirty_idx.arr[i] = (void *)(size_t)c->dirty_idx.arr[i]->lnum;
781 ubifs_release_lprops(c);
786 * scan_dirty_idx_cb - callback used by the scan for a dirty index LEB.
787 * @c: the UBIFS file-system description object
788 * @lprops: LEB properties to scan
789 * @in_tree: whether the LEB properties are in main memory
790 * @data: information passed to and from the caller of the scan
792 * This function returns a code that indicates whether the scan should continue
793 * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
794 * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
797 static int scan_dirty_idx_cb(struct ubifs_info *c,
798 const struct ubifs_lprops *lprops, int in_tree,
799 struct scan_data *data)
801 int ret = LPT_SCAN_CONTINUE;
803 /* Exclude LEBs that are currently in use */
804 if (lprops->flags & LPROPS_TAKEN)
805 return LPT_SCAN_CONTINUE;
806 /* Determine whether to add these LEB properties to the tree */
807 if (!in_tree && valuable(c, lprops))
809 /* Exclude non-index LEBs */
810 if (!(lprops->flags & LPROPS_INDEX))
812 /* Exclude LEBs with too little space */
813 if (lprops->free + lprops->dirty < c->min_idx_node_sz)
815 /* Finally we found space */
816 data->lnum = lprops->lnum;
817 return LPT_SCAN_ADD | LPT_SCAN_STOP;
821 * find_dirty_idx_leb - find a dirty index LEB.
822 * @c: the UBIFS file-system description object
824 * This function returns LEB number upon success and a negative error code upon
825 * failure. In particular, -ENOSPC is returned if a dirty index LEB is not
828 * Note that this function scans the entire LPT but it is called very rarely.
830 static int find_dirty_idx_leb(struct ubifs_info *c)
832 const struct ubifs_lprops *lprops;
833 struct ubifs_lpt_heap *heap;
834 struct scan_data data;
837 /* Check all structures in memory first */
839 heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
840 for (i = 0; i < heap->cnt; i++) {
841 lprops = heap->arr[i];
842 ret = scan_dirty_idx_cb(c, lprops, 1, &data);
843 if (ret & LPT_SCAN_STOP)
846 list_for_each_entry(lprops, &c->frdi_idx_list, list) {
847 ret = scan_dirty_idx_cb(c, lprops, 1, &data);
848 if (ret & LPT_SCAN_STOP)
851 list_for_each_entry(lprops, &c->uncat_list, list) {
852 ret = scan_dirty_idx_cb(c, lprops, 1, &data);
853 if (ret & LPT_SCAN_STOP)
856 if (c->pnodes_have >= c->pnode_cnt)
857 /* All pnodes are in memory, so skip scan */
859 err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
860 (ubifs_lpt_scan_callback)scan_dirty_idx_cb,
865 ubifs_assert(data.lnum >= c->main_first && data.lnum < c->leb_cnt);
866 c->lscan_lnum = data.lnum;
867 lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
869 return PTR_ERR(lprops);
870 ubifs_assert(lprops->lnum == data.lnum);
871 ubifs_assert(lprops->free + lprops->dirty >= c->min_idx_node_sz);
872 ubifs_assert(!(lprops->flags & LPROPS_TAKEN));
873 ubifs_assert((lprops->flags & LPROPS_INDEX));
875 dbg_find("found dirty LEB %d, free %d, dirty %d, flags %#x",
876 lprops->lnum, lprops->free, lprops->dirty, lprops->flags);
878 lprops = ubifs_change_lp(c, lprops, LPROPS_NC, LPROPS_NC,
879 lprops->flags | LPROPS_TAKEN, 0);
881 return PTR_ERR(lprops);
887 * get_idx_gc_leb - try to get a LEB number from trivial GC.
888 * @c: the UBIFS file-system description object
890 static int get_idx_gc_leb(struct ubifs_info *c)
892 const struct ubifs_lprops *lp;
895 err = ubifs_get_idx_gc_leb(c);
900 * The LEB was due to be unmapped after the commit but
901 * it is needed now for this commit.
903 lp = ubifs_lpt_lookup_dirty(c, lnum);
906 lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
907 lp->flags | LPROPS_INDEX, -1);
910 dbg_find("LEB %d, dirty %d and free %d flags %#x",
911 lp->lnum, lp->dirty, lp->free, lp->flags);
916 * find_dirtiest_idx_leb - find dirtiest index LEB from dirtiest array.
917 * @c: the UBIFS file-system description object
919 static int find_dirtiest_idx_leb(struct ubifs_info *c)
921 const struct ubifs_lprops *lp;
925 if (!c->dirty_idx.cnt)
927 /* The lprops pointers were replaced by LEB numbers */
928 lnum = (size_t)c->dirty_idx.arr[--c->dirty_idx.cnt];
929 lp = ubifs_lpt_lookup(c, lnum);
932 if ((lp->flags & LPROPS_TAKEN) || !(lp->flags & LPROPS_INDEX))
934 lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
935 lp->flags | LPROPS_TAKEN, 0);
940 dbg_find("LEB %d, dirty %d and free %d flags %#x", lp->lnum, lp->dirty,
941 lp->free, lp->flags);
942 ubifs_assert(lp->flags | LPROPS_TAKEN);
943 ubifs_assert(lp->flags | LPROPS_INDEX);
948 * ubifs_find_dirty_idx_leb - try to find dirtiest index LEB as at last commit.
949 * @c: the UBIFS file-system description object
951 * This function attempts to find an untaken index LEB with the most free and
952 * dirty space that can be used without overwriting index nodes that were in the
953 * last index committed.
955 int ubifs_find_dirty_idx_leb(struct ubifs_info *c)
962 * We made an array of the dirtiest index LEB numbers as at the start of
963 * last commit. Try that array first.
965 err = find_dirtiest_idx_leb(c);
967 /* Next try scanning the entire LPT */
969 err = find_dirty_idx_leb(c);
971 /* Finally take any index LEBs awaiting trivial GC */
973 err = get_idx_gc_leb(c);
975 ubifs_release_lprops(c);