2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
23 /* This file implements TNC functions for committing */
25 #include <linux/random.h>
29 * make_idx_node - make an index node for fill-the-gaps method of TNC commit.
30 * @c: UBIFS file-system description object
31 * @idx: buffer in which to place new index node
32 * @znode: znode from which to make new index node
33 * @lnum: LEB number where new index node will be written
34 * @offs: offset where new index node will be written
35 * @len: length of new index node
37 static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx,
38 struct ubifs_znode *znode, int lnum, int offs, int len)
40 struct ubifs_znode *zp;
41 u8 hash[UBIFS_HASH_ARR_SZ];
45 idx->ch.node_type = UBIFS_IDX_NODE;
46 idx->child_cnt = cpu_to_le16(znode->child_cnt);
47 idx->level = cpu_to_le16(znode->level);
48 for (i = 0; i < znode->child_cnt; i++) {
49 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
50 struct ubifs_zbranch *zbr = &znode->zbranch[i];
52 key_write_idx(c, &zbr->key, &br->key);
53 br->lnum = cpu_to_le32(zbr->lnum);
54 br->offs = cpu_to_le32(zbr->offs);
55 br->len = cpu_to_le32(zbr->len);
56 ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br));
57 if (!zbr->lnum || !zbr->len) {
58 ubifs_err(c, "bad ref in znode");
59 ubifs_dump_znode(c, znode);
61 ubifs_dump_znode(c, zbr->znode);
66 ubifs_prepare_node(c, idx, len, 0);
67 ubifs_node_calc_hash(c, idx, hash);
73 err = insert_old_idx_znode(c, znode);
75 /* Update the parent */
78 struct ubifs_zbranch *zbr;
80 zbr = &zp->zbranch[znode->iip];
84 ubifs_copy_hash(c, hash, zbr->hash);
89 ubifs_copy_hash(c, hash, c->zroot.hash);
91 c->calc_idx_sz += ALIGN(len, 8);
93 atomic_long_dec(&c->dirty_zn_cnt);
95 ubifs_assert(c, ubifs_zn_dirty(znode));
96 ubifs_assert(c, ubifs_zn_cow(znode));
99 * Note, unlike 'write_index()' we do not add memory barriers here
100 * because this function is called with @c->tnc_mutex locked.
102 __clear_bit(DIRTY_ZNODE, &znode->flags);
103 __clear_bit(COW_ZNODE, &znode->flags);
109 * fill_gap - make index nodes in gaps in dirty index LEBs.
110 * @c: UBIFS file-system description object
111 * @lnum: LEB number that gap appears in
112 * @gap_start: offset of start of gap
113 * @gap_end: offset of end of gap
114 * @dirt: adds dirty space to this
116 * This function returns the number of index nodes written into the gap.
118 static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end,
121 int len, gap_remains, gap_pos, written, pad_len;
123 ubifs_assert(c, (gap_start & 7) == 0);
124 ubifs_assert(c, (gap_end & 7) == 0);
125 ubifs_assert(c, gap_end >= gap_start);
127 gap_remains = gap_end - gap_start;
133 len = ubifs_idx_node_sz(c, c->enext->child_cnt);
134 if (len < gap_remains) {
135 struct ubifs_znode *znode = c->enext;
136 const int alen = ALIGN(len, 8);
139 ubifs_assert(c, alen <= gap_remains);
140 err = make_idx_node(c, c->ileb_buf + gap_pos, znode,
146 c->enext = znode->cnext;
147 if (c->enext == c->cnext)
153 if (gap_end == c->leb_size) {
154 c->ileb_len = ALIGN(gap_pos, c->min_io_size);
155 /* Pad to end of min_io_size */
156 pad_len = c->ileb_len - gap_pos;
158 /* Pad to end of gap */
159 pad_len = gap_remains;
160 dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d",
161 lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len);
162 ubifs_pad(c, c->ileb_buf + gap_pos, pad_len);
168 * find_old_idx - find an index node obsoleted since the last commit start.
169 * @c: UBIFS file-system description object
170 * @lnum: LEB number of obsoleted index node
171 * @offs: offset of obsoleted index node
173 * Returns %1 if found and %0 otherwise.
175 static int find_old_idx(struct ubifs_info *c, int lnum, int offs)
177 struct ubifs_old_idx *o;
180 p = c->old_idx.rb_node;
182 o = rb_entry(p, struct ubifs_old_idx, rb);
185 else if (lnum > o->lnum)
187 else if (offs < o->offs)
189 else if (offs > o->offs)
198 * is_idx_node_in_use - determine if an index node can be overwritten.
199 * @c: UBIFS file-system description object
200 * @key: key of index node
201 * @level: index node level
202 * @lnum: LEB number of index node
203 * @offs: offset of index node
205 * If @key / @lnum / @offs identify an index node that was not part of the old
206 * index, then this function returns %0 (obsolete). Else if the index node was
207 * part of the old index but is now dirty %1 is returned, else if it is clean %2
208 * is returned. A negative error code is returned on failure.
210 static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
211 int level, int lnum, int offs)
215 ret = is_idx_node_in_tnc(c, key, level, lnum, offs);
217 return ret; /* Error code */
219 if (find_old_idx(c, lnum, offs))
225 * layout_leb_in_gaps - layout index nodes using in-the-gaps method.
226 * @c: UBIFS file-system description object
227 * @p: return LEB number here
229 * This function lays out new index nodes for dirty znodes using in-the-gaps
230 * method of TNC commit.
231 * This function merely puts the next znode into the next gap, making no attempt
232 * to try to maximise the number of znodes that fit.
233 * This function returns the number of index nodes written into the gaps, or a
234 * negative error code on failure.
236 static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
238 struct ubifs_scan_leb *sleb;
239 struct ubifs_scan_node *snod;
240 int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written;
243 /* Get an index LEB with lots of obsolete index nodes */
244 lnum = ubifs_find_dirty_idx_leb(c);
247 * There also may be dirt in the index head that could be
248 * filled, however we do not check there at present.
250 return lnum; /* Error code */
252 dbg_gc("LEB %d", lnum);
254 * Scan the index LEB. We use the generic scan for this even though
255 * it is more comprehensive and less efficient than is needed for this
258 sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0);
261 return PTR_ERR(sleb);
263 list_for_each_entry(snod, &sleb->nodes, list) {
264 struct ubifs_idx_node *idx;
267 ubifs_assert(c, snod->type == UBIFS_IDX_NODE);
269 key_read(c, ubifs_idx_key(c, idx), &snod->key);
270 level = le16_to_cpu(idx->level);
271 /* Determine if the index node is in use (not obsolete) */
272 in_use = is_idx_node_in_use(c, &snod->key, level, lnum,
275 ubifs_scan_destroy(sleb);
276 return in_use; /* Error code */
280 dirt += ALIGN(snod->len, 8);
282 * The obsolete index nodes form gaps that can be
283 * overwritten. This gap has ended because we have
284 * found an index node that is still in use
287 gap_end = snod->offs;
288 /* Try to fill gap */
289 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
291 ubifs_scan_destroy(sleb);
292 return written; /* Error code */
294 tot_written += written;
295 gap_start = ALIGN(snod->offs + snod->len, 8);
298 ubifs_scan_destroy(sleb);
299 c->ileb_len = c->leb_size;
300 gap_end = c->leb_size;
301 /* Try to fill gap */
302 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
304 return written; /* Error code */
305 tot_written += written;
306 if (tot_written == 0) {
307 struct ubifs_lprops lp;
309 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
310 err = ubifs_read_one_lp(c, lnum, &lp);
313 if (lp.free == c->leb_size) {
315 * We must have snatched this LEB from the idx_gc list
316 * so we need to correct the free and dirty space.
318 err = ubifs_change_one_lp(c, lnum,
319 c->leb_size - c->ileb_len,
326 err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt,
330 err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len);
333 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
338 * get_leb_cnt - calculate the number of empty LEBs needed to commit.
339 * @c: UBIFS file-system description object
340 * @cnt: number of znodes to commit
342 * This function returns the number of empty LEBs needed to commit @cnt znodes
343 * to the current index head. The number is not exact and may be more than
346 static int get_leb_cnt(struct ubifs_info *c, int cnt)
350 /* Assume maximum index node size (i.e. overestimate space needed) */
351 cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz;
354 d = c->leb_size / c->max_idx_node_sz;
355 return DIV_ROUND_UP(cnt, d);
359 * layout_in_gaps - in-the-gaps method of committing TNC.
360 * @c: UBIFS file-system description object
361 * @cnt: number of dirty znodes to commit.
363 * This function lays out new index nodes for dirty znodes using in-the-gaps
364 * method of TNC commit.
366 * This function returns %0 on success and a negative error code on failure.
368 static int layout_in_gaps(struct ubifs_info *c, int cnt)
370 int err, leb_needed_cnt, written, *p;
372 dbg_gc("%d znodes to write", cnt);
374 c->gap_lebs = kmalloc_array(c->lst.idx_lebs + 1, sizeof(int),
381 ubifs_assert(c, p < c->gap_lebs + c->lst.idx_lebs);
382 written = layout_leb_in_gaps(c, p);
385 if (err != -ENOSPC) {
390 if (!dbg_is_chk_index(c)) {
392 * Do not print scary warnings if the debugging
393 * option which forces in-the-gaps is enabled.
395 ubifs_warn(c, "out of space");
396 ubifs_dump_budg(c, &c->bi);
397 ubifs_dump_lprops(c);
399 /* Try to commit anyway */
404 leb_needed_cnt = get_leb_cnt(c, cnt);
405 dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
406 leb_needed_cnt, c->ileb_cnt);
407 } while (leb_needed_cnt > c->ileb_cnt);
414 * layout_in_empty_space - layout index nodes in empty space.
415 * @c: UBIFS file-system description object
417 * This function lays out new index nodes for dirty znodes using empty LEBs.
419 * This function returns %0 on success and a negative error code on failure.
421 static int layout_in_empty_space(struct ubifs_info *c)
423 struct ubifs_znode *znode, *cnext, *zp;
424 int lnum, offs, len, next_len, buf_len, buf_offs, used, avail;
431 lnum = c->ihead_lnum;
432 buf_offs = c->ihead_offs;
434 buf_len = ubifs_idx_node_sz(c, c->fanout);
435 buf_len = ALIGN(buf_len, c->min_io_size);
439 /* Ensure there is enough room for first write */
440 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
441 if (buf_offs + next_len > c->leb_size)
447 len = ubifs_idx_node_sz(c, znode->child_cnt);
449 /* Determine the index node position */
451 if (c->ileb_nxt >= c->ileb_cnt) {
452 ubifs_err(c, "out of space");
455 lnum = c->ilebs[c->ileb_nxt++];
461 offs = buf_offs + used;
467 /* Update the parent */
470 struct ubifs_zbranch *zbr;
474 zbr = &zp->zbranch[i];
479 c->zroot.lnum = lnum;
480 c->zroot.offs = offs;
483 c->calc_idx_sz += ALIGN(len, 8);
486 * Once lprops is updated, we can decrease the dirty znode count
487 * but it is easier to just do it here.
489 atomic_long_dec(&c->dirty_zn_cnt);
492 * Calculate the next index node length to see if there is
495 cnext = znode->cnext;
496 if (cnext == c->cnext)
499 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
501 /* Update buffer positions */
503 used += ALIGN(len, 8);
504 avail -= ALIGN(len, 8);
507 buf_offs + used + next_len <= c->leb_size &&
511 if (avail <= 0 && next_len &&
512 buf_offs + used + next_len <= c->leb_size)
515 blen = ALIGN(wlen, c->min_io_size);
517 /* The buffer is full or there are no more znodes to do */
520 if (buf_offs + next_len > c->leb_size) {
521 err = ubifs_update_one_lp(c, lnum,
522 c->leb_size - buf_offs, blen - used,
531 avail = buf_len - used;
534 err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs,
541 c->dbg->new_ihead_lnum = lnum;
542 c->dbg->new_ihead_offs = buf_offs;
548 * layout_commit - determine positions of index nodes to commit.
549 * @c: UBIFS file-system description object
550 * @no_space: indicates that insufficient empty LEBs were allocated
551 * @cnt: number of znodes to commit
553 * Calculate and update the positions of index nodes to commit. If there were
554 * an insufficient number of empty LEBs allocated, then index nodes are placed
555 * into the gaps created by obsolete index nodes in non-empty index LEBs. For
556 * this purpose, an obsolete index node is one that was not in the index as at
557 * the end of the last commit. To write "in-the-gaps" requires that those index
558 * LEBs are updated atomically in-place.
560 static int layout_commit(struct ubifs_info *c, int no_space, int cnt)
565 err = layout_in_gaps(c, cnt);
569 err = layout_in_empty_space(c);
574 * find_first_dirty - find first dirty znode.
575 * @znode: znode to begin searching from
577 static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode)
585 if (znode->level == 0) {
586 if (ubifs_zn_dirty(znode))
591 for (i = 0; i < znode->child_cnt; i++) {
592 struct ubifs_zbranch *zbr = &znode->zbranch[i];
594 if (zbr->znode && ubifs_zn_dirty(zbr->znode)) {
601 if (ubifs_zn_dirty(znode))
609 * find_next_dirty - find next dirty znode.
610 * @znode: znode to begin searching from
612 static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode)
614 int n = znode->iip + 1;
616 znode = znode->parent;
619 for (; n < znode->child_cnt; n++) {
620 struct ubifs_zbranch *zbr = &znode->zbranch[n];
622 if (zbr->znode && ubifs_zn_dirty(zbr->znode))
623 return find_first_dirty(zbr->znode);
629 * get_znodes_to_commit - create list of dirty znodes to commit.
630 * @c: UBIFS file-system description object
632 * This function returns the number of znodes to commit.
634 static int get_znodes_to_commit(struct ubifs_info *c)
636 struct ubifs_znode *znode, *cnext;
639 c->cnext = find_first_dirty(c->zroot.znode);
640 znode = c->enext = c->cnext;
642 dbg_cmt("no znodes to commit");
647 ubifs_assert(c, !ubifs_zn_cow(znode));
648 __set_bit(COW_ZNODE, &znode->flags);
650 cnext = find_next_dirty(znode);
652 znode->cnext = c->cnext;
655 znode->cparent = znode->parent;
656 znode->ciip = znode->iip;
657 znode->cnext = cnext;
661 dbg_cmt("committing %d znodes", cnt);
662 ubifs_assert(c, cnt == atomic_long_read(&c->dirty_zn_cnt));
667 * alloc_idx_lebs - allocate empty LEBs to be used to commit.
668 * @c: UBIFS file-system description object
669 * @cnt: number of znodes to commit
671 * This function returns %-ENOSPC if it cannot allocate a sufficient number of
672 * empty LEBs. %0 is returned on success, otherwise a negative error code
675 static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
677 int i, leb_cnt, lnum;
681 leb_cnt = get_leb_cnt(c, cnt);
682 dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt);
685 c->ilebs = kmalloc_array(leb_cnt, sizeof(int), GFP_NOFS);
688 for (i = 0; i < leb_cnt; i++) {
689 lnum = ubifs_find_free_leb_for_idx(c);
692 c->ilebs[c->ileb_cnt++] = lnum;
693 dbg_cmt("LEB %d", lnum);
695 if (dbg_is_chk_index(c) && !(prandom_u32() & 7))
701 * free_unused_idx_lebs - free unused LEBs that were allocated for the commit.
702 * @c: UBIFS file-system description object
704 * It is possible that we allocate more empty LEBs for the commit than we need.
705 * This functions frees the surplus.
707 * This function returns %0 on success and a negative error code on failure.
709 static int free_unused_idx_lebs(struct ubifs_info *c)
711 int i, err = 0, lnum, er;
713 for (i = c->ileb_nxt; i < c->ileb_cnt; i++) {
715 dbg_cmt("LEB %d", lnum);
716 er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
717 LPROPS_INDEX | LPROPS_TAKEN, 0);
725 * free_idx_lebs - free unused LEBs after commit end.
726 * @c: UBIFS file-system description object
728 * This function returns %0 on success and a negative error code on failure.
730 static int free_idx_lebs(struct ubifs_info *c)
734 err = free_unused_idx_lebs(c);
741 * ubifs_tnc_start_commit - start TNC commit.
742 * @c: UBIFS file-system description object
743 * @zroot: new index root position is returned here
745 * This function prepares the list of indexing nodes to commit and lays out
746 * their positions on flash. If there is not enough free space it uses the
747 * in-gap commit method. Returns zero in case of success and a negative error
748 * code in case of failure.
750 int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot)
754 mutex_lock(&c->tnc_mutex);
755 err = dbg_check_tnc(c, 1);
758 cnt = get_znodes_to_commit(c);
762 err = alloc_idx_lebs(c, cnt);
767 err = layout_commit(c, no_space, cnt);
770 ubifs_assert(c, atomic_long_read(&c->dirty_zn_cnt) == 0);
771 err = free_unused_idx_lebs(c);
776 memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch));
778 err = ubifs_save_dirty_idx_lnums(c);
782 spin_lock(&c->space_lock);
784 * Although we have not finished committing yet, update size of the
785 * committed index ('c->bi.old_idx_sz') and zero out the index growth
786 * budget. It is OK to do this now, because we've reserved all the
787 * space which is needed to commit the index, and it is save for the
788 * budgeting subsystem to assume the index is already committed,
789 * even though it is not.
791 ubifs_assert(c, c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c));
792 c->bi.old_idx_sz = c->calc_idx_sz;
793 c->bi.uncommitted_idx = 0;
794 c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
795 spin_unlock(&c->space_lock);
796 mutex_unlock(&c->tnc_mutex);
798 dbg_cmt("number of index LEBs %d", c->lst.idx_lebs);
799 dbg_cmt("size of index %llu", c->calc_idx_sz);
805 mutex_unlock(&c->tnc_mutex);
810 * write_index - write index nodes.
811 * @c: UBIFS file-system description object
813 * This function writes the index nodes whose positions were laid out in the
814 * layout_in_empty_space function.
816 static int write_index(struct ubifs_info *c)
818 struct ubifs_idx_node *idx;
819 struct ubifs_znode *znode, *cnext;
820 int i, lnum, offs, len, next_len, buf_len, buf_offs, used;
821 int avail, wlen, err, lnum_pos = 0, blen, nxt_offs;
828 * Always write index nodes to the index head so that index nodes and
829 * other types of nodes are never mixed in the same erase block.
831 lnum = c->ihead_lnum;
832 buf_offs = c->ihead_offs;
834 /* Allocate commit buffer */
835 buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size);
839 /* Ensure there is enough room for first write */
840 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
841 if (buf_offs + next_len > c->leb_size) {
842 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0,
850 u8 hash[UBIFS_HASH_ARR_SZ];
855 idx = c->cbuf + used;
857 /* Make index node */
858 idx->ch.node_type = UBIFS_IDX_NODE;
859 idx->child_cnt = cpu_to_le16(znode->child_cnt);
860 idx->level = cpu_to_le16(znode->level);
861 for (i = 0; i < znode->child_cnt; i++) {
862 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
863 struct ubifs_zbranch *zbr = &znode->zbranch[i];
865 key_write_idx(c, &zbr->key, &br->key);
866 br->lnum = cpu_to_le32(zbr->lnum);
867 br->offs = cpu_to_le32(zbr->offs);
868 br->len = cpu_to_le32(zbr->len);
869 ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br));
870 if (!zbr->lnum || !zbr->len) {
871 ubifs_err(c, "bad ref in znode");
872 ubifs_dump_znode(c, znode);
874 ubifs_dump_znode(c, zbr->znode);
879 len = ubifs_idx_node_sz(c, znode->child_cnt);
880 ubifs_prepare_node(c, idx, len, 0);
881 ubifs_node_calc_hash(c, idx, hash);
883 mutex_lock(&c->tnc_mutex);
886 ubifs_copy_hash(c, hash,
887 znode->cparent->zbranch[znode->ciip].hash);
890 if (!ubifs_zn_obsolete(znode))
891 ubifs_copy_hash(c, hash,
892 znode->parent->zbranch[znode->iip].hash);
894 ubifs_copy_hash(c, hash, c->zroot.hash);
897 mutex_unlock(&c->tnc_mutex);
899 /* Determine the index node position */
901 lnum = c->ilebs[lnum_pos++];
906 offs = buf_offs + used;
908 if (lnum != znode->lnum || offs != znode->offs ||
910 ubifs_err(c, "inconsistent znode posn");
914 /* Grab some stuff from znode while we still can */
915 cnext = znode->cnext;
917 ubifs_assert(c, ubifs_zn_dirty(znode));
918 ubifs_assert(c, ubifs_zn_cow(znode));
921 * It is important that other threads should see %DIRTY_ZNODE
922 * flag cleared before %COW_ZNODE. Specifically, it matters in
923 * the 'dirty_cow_znode()' function. This is the reason for the
924 * first barrier. Also, we want the bit changes to be seen to
925 * other threads ASAP, to avoid unnecesarry copying, which is
926 * the reason for the second barrier.
928 clear_bit(DIRTY_ZNODE, &znode->flags);
929 smp_mb__before_atomic();
930 clear_bit(COW_ZNODE, &znode->flags);
931 smp_mb__after_atomic();
934 * We have marked the znode as clean but have not updated the
935 * @c->clean_zn_cnt counter. If this znode becomes dirty again
936 * before 'free_obsolete_znodes()' is called, then
937 * @c->clean_zn_cnt will be decremented before it gets
938 * incremented (resulting in 2 decrements for the same znode).
939 * This means that @c->clean_zn_cnt may become negative for a
942 * Q: why we cannot increment @c->clean_zn_cnt?
943 * A: because we do not have the @c->tnc_mutex locked, and the
944 * following code would be racy and buggy:
946 * if (!ubifs_zn_obsolete(znode)) {
947 * atomic_long_inc(&c->clean_zn_cnt);
948 * atomic_long_inc(&ubifs_clean_zn_cnt);
951 * Thus, we just delay the @c->clean_zn_cnt update until we
952 * have the mutex locked.
955 /* Do not access znode from this point on */
957 /* Update buffer positions */
959 used += ALIGN(len, 8);
960 avail -= ALIGN(len, 8);
963 * Calculate the next index node length to see if there is
966 if (cnext == c->cnext)
969 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
971 nxt_offs = buf_offs + used + next_len;
972 if (next_len && nxt_offs <= c->leb_size) {
978 wlen = ALIGN(wlen, 8);
979 blen = ALIGN(wlen, c->min_io_size);
980 ubifs_pad(c, c->cbuf + wlen, blen - wlen);
983 /* The buffer is full or there are no more znodes to do */
984 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, blen);
989 if (nxt_offs > c->leb_size) {
990 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0,
999 avail = buf_len - used;
1000 memmove(c->cbuf, c->cbuf + blen, used);
1006 if (lnum != c->dbg->new_ihead_lnum ||
1007 buf_offs != c->dbg->new_ihead_offs) {
1008 ubifs_err(c, "inconsistent ihead");
1012 c->ihead_lnum = lnum;
1013 c->ihead_offs = buf_offs;
1019 * free_obsolete_znodes - free obsolete znodes.
1020 * @c: UBIFS file-system description object
1022 * At the end of commit end, obsolete znodes are freed.
1024 static void free_obsolete_znodes(struct ubifs_info *c)
1026 struct ubifs_znode *znode, *cnext;
1031 cnext = znode->cnext;
1032 if (ubifs_zn_obsolete(znode))
1035 znode->cnext = NULL;
1036 atomic_long_inc(&c->clean_zn_cnt);
1037 atomic_long_inc(&ubifs_clean_zn_cnt);
1039 } while (cnext != c->cnext);
1043 * return_gap_lebs - return LEBs used by the in-gap commit method.
1044 * @c: UBIFS file-system description object
1046 * This function clears the "taken" flag for the LEBs which were used by the
1047 * "commit in-the-gaps" method.
1049 static int return_gap_lebs(struct ubifs_info *c)
1057 for (p = c->gap_lebs; *p != -1; p++) {
1058 err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0,
1070 * ubifs_tnc_end_commit - update the TNC for commit end.
1071 * @c: UBIFS file-system description object
1073 * Write the dirty znodes.
1075 int ubifs_tnc_end_commit(struct ubifs_info *c)
1082 err = return_gap_lebs(c);
1086 err = write_index(c);
1090 mutex_lock(&c->tnc_mutex);
1092 dbg_cmt("TNC height is %d", c->zroot.znode->level + 1);
1094 free_obsolete_znodes(c);
1100 mutex_unlock(&c->tnc_mutex);