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-rw-r--r--fs/ubifs/tnc_commit.c1103
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diff --git a/fs/ubifs/tnc_commit.c b/fs/ubifs/tnc_commit.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/* This file implements TNC functions for committing */
24
25#include "ubifs.h"
26
27/**
28 * make_idx_node - make an index node for fill-the-gaps method of TNC commit.
29 * @c: UBIFS file-system description object
30 * @idx: buffer in which to place new index node
31 * @znode: znode from which to make new index node
32 * @lnum: LEB number where new index node will be written
33 * @offs: offset where new index node will be written
34 * @len: length of new index node
35 */
36static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx,
37 struct ubifs_znode *znode, int lnum, int offs, int len)
38{
39 struct ubifs_znode *zp;
40 int i, err;
41
42 /* Make index node */
43 idx->ch.node_type = UBIFS_IDX_NODE;
44 idx->child_cnt = cpu_to_le16(znode->child_cnt);
45 idx->level = cpu_to_le16(znode->level);
46 for (i = 0; i < znode->child_cnt; i++) {
47 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
48 struct ubifs_zbranch *zbr = &znode->zbranch[i];
49
50 key_write_idx(c, &zbr->key, &br->key);
51 br->lnum = cpu_to_le32(zbr->lnum);
52 br->offs = cpu_to_le32(zbr->offs);
53 br->len = cpu_to_le32(zbr->len);
54 if (!zbr->lnum || !zbr->len) {
55 ubifs_err("bad ref in znode");
56 dbg_dump_znode(c, znode);
57 if (zbr->znode)
58 dbg_dump_znode(c, zbr->znode);
59 }
60 }
61 ubifs_prepare_node(c, idx, len, 0);
62
63#ifdef CONFIG_UBIFS_FS_DEBUG
64 znode->lnum = lnum;
65 znode->offs = offs;
66 znode->len = len;
67#endif
68
69 err = insert_old_idx_znode(c, znode);
70
71 /* Update the parent */
72 zp = znode->parent;
73 if (zp) {
74 struct ubifs_zbranch *zbr;
75
76 zbr = &zp->zbranch[znode->iip];
77 zbr->lnum = lnum;
78 zbr->offs = offs;
79 zbr->len = len;
80 } else {
81 c->zroot.lnum = lnum;
82 c->zroot.offs = offs;
83 c->zroot.len = len;
84 }
85 c->calc_idx_sz += ALIGN(len, 8);
86
87 atomic_long_dec(&c->dirty_zn_cnt);
88
89 ubifs_assert(ubifs_zn_dirty(znode));
90 ubifs_assert(test_bit(COW_ZNODE, &znode->flags));
91
92 __clear_bit(DIRTY_ZNODE, &znode->flags);
93 __clear_bit(COW_ZNODE, &znode->flags);
94
95 return err;
96}
97
98/**
99 * fill_gap - make index nodes in gaps in dirty index LEBs.
100 * @c: UBIFS file-system description object
101 * @lnum: LEB number that gap appears in
102 * @gap_start: offset of start of gap
103 * @gap_end: offset of end of gap
104 * @dirt: adds dirty space to this
105 *
106 * This function returns the number of index nodes written into the gap.
107 */
108static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end,
109 int *dirt)
110{
111 int len, gap_remains, gap_pos, written, pad_len;
112
113 ubifs_assert((gap_start & 7) == 0);
114 ubifs_assert((gap_end & 7) == 0);
115 ubifs_assert(gap_end >= gap_start);
116
117 gap_remains = gap_end - gap_start;
118 if (!gap_remains)
119 return 0;
120 gap_pos = gap_start;
121 written = 0;
122 while (c->enext) {
123 len = ubifs_idx_node_sz(c, c->enext->child_cnt);
124 if (len < gap_remains) {
125 struct ubifs_znode *znode = c->enext;
126 const int alen = ALIGN(len, 8);
127 int err;
128
129 ubifs_assert(alen <= gap_remains);
130 err = make_idx_node(c, c->ileb_buf + gap_pos, znode,
131 lnum, gap_pos, len);
132 if (err)
133 return err;
134 gap_remains -= alen;
135 gap_pos += alen;
136 c->enext = znode->cnext;
137 if (c->enext == c->cnext)
138 c->enext = NULL;
139 written += 1;
140 } else
141 break;
142 }
143 if (gap_end == c->leb_size) {
144 c->ileb_len = ALIGN(gap_pos, c->min_io_size);
145 /* Pad to end of min_io_size */
146 pad_len = c->ileb_len - gap_pos;
147 } else
148 /* Pad to end of gap */
149 pad_len = gap_remains;
150 dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d",
151 lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len);
152 ubifs_pad(c, c->ileb_buf + gap_pos, pad_len);
153 *dirt += pad_len;
154 return written;
155}
156
157/**
158 * find_old_idx - find an index node obsoleted since the last commit start.
159 * @c: UBIFS file-system description object
160 * @lnum: LEB number of obsoleted index node
161 * @offs: offset of obsoleted index node
162 *
163 * Returns %1 if found and %0 otherwise.
164 */
165static int find_old_idx(struct ubifs_info *c, int lnum, int offs)
166{
167 struct ubifs_old_idx *o;
168 struct rb_node *p;
169
170 p = c->old_idx.rb_node;
171 while (p) {
172 o = rb_entry(p, struct ubifs_old_idx, rb);
173 if (lnum < o->lnum)
174 p = p->rb_left;
175 else if (lnum > o->lnum)
176 p = p->rb_right;
177 else if (offs < o->offs)
178 p = p->rb_left;
179 else if (offs > o->offs)
180 p = p->rb_right;
181 else
182 return 1;
183 }
184 return 0;
185}
186
187/**
188 * is_idx_node_in_use - determine if an index node can be overwritten.
189 * @c: UBIFS file-system description object
190 * @key: key of index node
191 * @level: index node level
192 * @lnum: LEB number of index node
193 * @offs: offset of index node
194 *
195 * If @key / @lnum / @offs identify an index node that was not part of the old
196 * index, then this function returns %0 (obsolete). Else if the index node was
197 * part of the old index but is now dirty %1 is returned, else if it is clean %2
198 * is returned. A negative error code is returned on failure.
199 */
200static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
201 int level, int lnum, int offs)
202{
203 int ret;
204
205 ret = is_idx_node_in_tnc(c, key, level, lnum, offs);
206 if (ret < 0)
207 return ret; /* Error code */
208 if (ret == 0)
209 if (find_old_idx(c, lnum, offs))
210 return 1;
211 return ret;
212}
213
214/**
215 * layout_leb_in_gaps - layout index nodes using in-the-gaps method.
216 * @c: UBIFS file-system description object
217 * @p: return LEB number here
218 *
219 * This function lays out new index nodes for dirty znodes using in-the-gaps
220 * method of TNC commit.
221 * This function merely puts the next znode into the next gap, making no attempt
222 * to try to maximise the number of znodes that fit.
223 * This function returns the number of index nodes written into the gaps, or a
224 * negative error code on failure.
225 */
226static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
227{
228 struct ubifs_scan_leb *sleb;
229 struct ubifs_scan_node *snod;
230 int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written;
231
232 tot_written = 0;
233 /* Get an index LEB with lots of obsolete index nodes */
234 lnum = ubifs_find_dirty_idx_leb(c);
235 if (lnum < 0)
236 /*
237 * There also may be dirt in the index head that could be
238 * filled, however we do not check there at present.
239 */
240 return lnum; /* Error code */
241 *p = lnum;
242 dbg_gc("LEB %d", lnum);
243 /*
244 * Scan the index LEB. We use the generic scan for this even though
245 * it is more comprehensive and less efficient than is needed for this
246 * purpose.
247 */
248 sleb = ubifs_scan(c, lnum, 0, c->ileb_buf);
249 c->ileb_len = 0;
250 if (IS_ERR(sleb))
251 return PTR_ERR(sleb);
252 gap_start = 0;
253 list_for_each_entry(snod, &sleb->nodes, list) {
254 struct ubifs_idx_node *idx;
255 int in_use, level;
256
257 ubifs_assert(snod->type == UBIFS_IDX_NODE);
258 idx = snod->node;
259 key_read(c, ubifs_idx_key(c, idx), &snod->key);
260 level = le16_to_cpu(idx->level);
261 /* Determine if the index node is in use (not obsolete) */
262 in_use = is_idx_node_in_use(c, &snod->key, level, lnum,
263 snod->offs);
264 if (in_use < 0) {
265 ubifs_scan_destroy(sleb);
266 return in_use; /* Error code */
267 }
268 if (in_use) {
269 if (in_use == 1)
270 dirt += ALIGN(snod->len, 8);
271 /*
272 * The obsolete index nodes form gaps that can be
273 * overwritten. This gap has ended because we have
274 * found an index node that is still in use
275 * i.e. not obsolete
276 */
277 gap_end = snod->offs;
278 /* Try to fill gap */
279 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
280 if (written < 0) {
281 ubifs_scan_destroy(sleb);
282 return written; /* Error code */
283 }
284 tot_written += written;
285 gap_start = ALIGN(snod->offs + snod->len, 8);
286 }
287 }
288 ubifs_scan_destroy(sleb);
289 c->ileb_len = c->leb_size;
290 gap_end = c->leb_size;
291 /* Try to fill gap */
292 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
293 if (written < 0)
294 return written; /* Error code */
295 tot_written += written;
296 if (tot_written == 0) {
297 struct ubifs_lprops lp;
298
299 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
300 err = ubifs_read_one_lp(c, lnum, &lp);
301 if (err)
302 return err;
303 if (lp.free == c->leb_size) {
304 /*
305 * We must have snatched this LEB from the idx_gc list
306 * so we need to correct the free and dirty space.
307 */
308 err = ubifs_change_one_lp(c, lnum,
309 c->leb_size - c->ileb_len,
310 dirt, 0, 0, 0);
311 if (err)
312 return err;
313 }
314 return 0;
315 }
316 err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt,
317 0, 0, 0);
318 if (err)
319 return err;
320 err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len,
321 UBI_SHORTTERM);
322 if (err)
323 return err;
324 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
325 return tot_written;
326}
327
328/**
329 * get_leb_cnt - calculate the number of empty LEBs needed to commit.
330 * @c: UBIFS file-system description object
331 * @cnt: number of znodes to commit
332 *
333 * This function returns the number of empty LEBs needed to commit @cnt znodes
334 * to the current index head. The number is not exact and may be more than
335 * needed.
336 */
337static int get_leb_cnt(struct ubifs_info *c, int cnt)
338{
339 int d;
340
341 /* Assume maximum index node size (i.e. overestimate space needed) */
342 cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz;
343 if (cnt < 0)
344 cnt = 0;
345 d = c->leb_size / c->max_idx_node_sz;
346 return DIV_ROUND_UP(cnt, d);
347}
348
349/**
350 * layout_in_gaps - in-the-gaps method of committing TNC.
351 * @c: UBIFS file-system description object
352 * @cnt: number of dirty znodes to commit.
353 *
354 * This function lays out new index nodes for dirty znodes using in-the-gaps
355 * method of TNC commit.
356 *
357 * This function returns %0 on success and a negative error code on failure.
358 */
359static int layout_in_gaps(struct ubifs_info *c, int cnt)
360{
361 int err, leb_needed_cnt, written, *p;
362
363 dbg_gc("%d znodes to write", cnt);
364
365 c->gap_lebs = kmalloc(sizeof(int) * (c->lst.idx_lebs + 1), GFP_NOFS);
366 if (!c->gap_lebs)
367 return -ENOMEM;
368
369 p = c->gap_lebs;
370 do {
371 ubifs_assert(p < c->gap_lebs + sizeof(int) * c->lst.idx_lebs);
372 written = layout_leb_in_gaps(c, p);
373 if (written < 0) {
374 err = written;
375 if (err == -ENOSPC) {
376 if (!dbg_force_in_the_gaps_enabled) {
377 /*
378 * Do not print scary warnings if the
379 * debugging option which forces
380 * in-the-gaps is enabled.
381 */
382 ubifs_err("out of space");
383 spin_lock(&c->space_lock);
384 dbg_dump_budg(c);
385 spin_unlock(&c->space_lock);
386 dbg_dump_lprops(c);
387 }
388 /* Try to commit anyway */
389 err = 0;
390 break;
391 }
392 kfree(c->gap_lebs);
393 c->gap_lebs = NULL;
394 return err;
395 }
396 p++;
397 cnt -= written;
398 leb_needed_cnt = get_leb_cnt(c, cnt);
399 dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
400 leb_needed_cnt, c->ileb_cnt);
401 } while (leb_needed_cnt > c->ileb_cnt);
402
403 *p = -1;
404 return 0;
405}
406
407/**
408 * layout_in_empty_space - layout index nodes in empty space.
409 * @c: UBIFS file-system description object
410 *
411 * This function lays out new index nodes for dirty znodes using empty LEBs.
412 *
413 * This function returns %0 on success and a negative error code on failure.
414 */
415static int layout_in_empty_space(struct ubifs_info *c)
416{
417 struct ubifs_znode *znode, *cnext, *zp;
418 int lnum, offs, len, next_len, buf_len, buf_offs, used, avail;
419 int wlen, blen, err;
420
421 cnext = c->enext;
422 if (!cnext)
423 return 0;
424
425 lnum = c->ihead_lnum;
426 buf_offs = c->ihead_offs;
427
428 buf_len = ubifs_idx_node_sz(c, c->fanout);
429 buf_len = ALIGN(buf_len, c->min_io_size);
430 used = 0;
431 avail = buf_len;
432
433 /* Ensure there is enough room for first write */
434 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
435 if (buf_offs + next_len > c->leb_size)
436 lnum = -1;
437
438 while (1) {
439 znode = cnext;
440
441 len = ubifs_idx_node_sz(c, znode->child_cnt);
442
443 /* Determine the index node position */
444 if (lnum == -1) {
445 if (c->ileb_nxt >= c->ileb_cnt) {
446 ubifs_err("out of space");
447 return -ENOSPC;
448 }
449 lnum = c->ilebs[c->ileb_nxt++];
450 buf_offs = 0;
451 used = 0;
452 avail = buf_len;
453 }
454
455 offs = buf_offs + used;
456
457#ifdef CONFIG_UBIFS_FS_DEBUG
458 znode->lnum = lnum;
459 znode->offs = offs;
460 znode->len = len;
461#endif
462
463 /* Update the parent */
464 zp = znode->parent;
465 if (zp) {
466 struct ubifs_zbranch *zbr;
467 int i;
468
469 i = znode->iip;
470 zbr = &zp->zbranch[i];
471 zbr->lnum = lnum;
472 zbr->offs = offs;
473 zbr->len = len;
474 } else {
475 c->zroot.lnum = lnum;
476 c->zroot.offs = offs;
477 c->zroot.len = len;
478 }
479 c->calc_idx_sz += ALIGN(len, 8);
480
481 /*
482 * Once lprops is updated, we can decrease the dirty znode count
483 * but it is easier to just do it here.
484 */
485 atomic_long_dec(&c->dirty_zn_cnt);
486
487 /*
488 * Calculate the next index node length to see if there is
489 * enough room for it
490 */
491 cnext = znode->cnext;
492 if (cnext == c->cnext)
493 next_len = 0;
494 else
495 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
496
497 if (c->min_io_size == 1) {
498 buf_offs += ALIGN(len, 8);
499 if (next_len) {
500 if (buf_offs + next_len <= c->leb_size)
501 continue;
502 err = ubifs_update_one_lp(c, lnum, 0,
503 c->leb_size - buf_offs, 0, 0);
504 if (err)
505 return err;
506 lnum = -1;
507 continue;
508 }
509 err = ubifs_update_one_lp(c, lnum,
510 c->leb_size - buf_offs, 0, 0, 0);
511 if (err)
512 return err;
513 break;
514 }
515
516 /* Update buffer positions */
517 wlen = used + len;
518 used += ALIGN(len, 8);
519 avail -= ALIGN(len, 8);
520
521 if (next_len != 0 &&
522 buf_offs + used + next_len <= c->leb_size &&
523 avail > 0)
524 continue;
525
526 if (avail <= 0 && next_len &&
527 buf_offs + used + next_len <= c->leb_size)
528 blen = buf_len;
529 else
530 blen = ALIGN(wlen, c->min_io_size);
531
532 /* The buffer is full or there are no more znodes to do */
533 buf_offs += blen;
534 if (next_len) {
535 if (buf_offs + next_len > c->leb_size) {
536 err = ubifs_update_one_lp(c, lnum,
537 c->leb_size - buf_offs, blen - used,
538 0, 0);
539 if (err)
540 return err;
541 lnum = -1;
542 }
543 used -= blen;
544 if (used < 0)
545 used = 0;
546 avail = buf_len - used;
547 continue;
548 }
549 err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs,
550 blen - used, 0, 0);
551 if (err)
552 return err;
553 break;
554 }
555
556#ifdef CONFIG_UBIFS_FS_DEBUG
557 c->new_ihead_lnum = lnum;
558 c->new_ihead_offs = buf_offs;
559#endif
560
561 return 0;
562}
563
564/**
565 * layout_commit - determine positions of index nodes to commit.
566 * @c: UBIFS file-system description object
567 * @no_space: indicates that insufficient empty LEBs were allocated
568 * @cnt: number of znodes to commit
569 *
570 * Calculate and update the positions of index nodes to commit. If there were
571 * an insufficient number of empty LEBs allocated, then index nodes are placed
572 * into the gaps created by obsolete index nodes in non-empty index LEBs. For
573 * this purpose, an obsolete index node is one that was not in the index as at
574 * the end of the last commit. To write "in-the-gaps" requires that those index
575 * LEBs are updated atomically in-place.
576 */
577static int layout_commit(struct ubifs_info *c, int no_space, int cnt)
578{
579 int err;
580
581 if (no_space) {
582 err = layout_in_gaps(c, cnt);
583 if (err)
584 return err;
585 }
586 err = layout_in_empty_space(c);
587 return err;
588}
589
590/**
591 * find_first_dirty - find first dirty znode.
592 * @znode: znode to begin searching from
593 */
594static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode)
595{
596 int i, cont;
597
598 if (!znode)
599 return NULL;
600
601 while (1) {
602 if (znode->level == 0) {
603 if (ubifs_zn_dirty(znode))
604 return znode;
605 return NULL;
606 }
607 cont = 0;
608 for (i = 0; i < znode->child_cnt; i++) {
609 struct ubifs_zbranch *zbr = &znode->zbranch[i];
610
611 if (zbr->znode && ubifs_zn_dirty(zbr->znode)) {
612 znode = zbr->znode;
613 cont = 1;
614 break;
615 }
616 }
617 if (!cont) {
618 if (ubifs_zn_dirty(znode))
619 return znode;
620 return NULL;
621 }
622 }
623}
624
625/**
626 * find_next_dirty - find next dirty znode.
627 * @znode: znode to begin searching from
628 */
629static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode)
630{
631 int n = znode->iip + 1;
632
633 znode = znode->parent;
634 if (!znode)
635 return NULL;
636 for (; n < znode->child_cnt; n++) {
637 struct ubifs_zbranch *zbr = &znode->zbranch[n];
638
639 if (zbr->znode && ubifs_zn_dirty(zbr->znode))
640 return find_first_dirty(zbr->znode);
641 }
642 return znode;
643}
644
645/**
646 * get_znodes_to_commit - create list of dirty znodes to commit.
647 * @c: UBIFS file-system description object
648 *
649 * This function returns the number of znodes to commit.
650 */
651static int get_znodes_to_commit(struct ubifs_info *c)
652{
653 struct ubifs_znode *znode, *cnext;
654 int cnt = 0;
655
656 c->cnext = find_first_dirty(c->zroot.znode);
657 znode = c->enext = c->cnext;
658 if (!znode) {
659 dbg_cmt("no znodes to commit");
660 return 0;
661 }
662 cnt += 1;
663 while (1) {
664 ubifs_assert(!test_bit(COW_ZNODE, &znode->flags));
665 __set_bit(COW_ZNODE, &znode->flags);
666 znode->alt = 0;
667 cnext = find_next_dirty(znode);
668 if (!cnext) {
669 znode->cnext = c->cnext;
670 break;
671 }
672 znode->cnext = cnext;
673 znode = cnext;
674 cnt += 1;
675 }
676 dbg_cmt("committing %d znodes", cnt);
677 ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt));
678 return cnt;
679}
680
681/**
682 * alloc_idx_lebs - allocate empty LEBs to be used to commit.
683 * @c: UBIFS file-system description object
684 * @cnt: number of znodes to commit
685 *
686 * This function returns %-ENOSPC if it cannot allocate a sufficient number of
687 * empty LEBs. %0 is returned on success, otherwise a negative error code
688 * is returned.
689 */
690static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
691{
692 int i, leb_cnt, lnum;
693
694 c->ileb_cnt = 0;
695 c->ileb_nxt = 0;
696 leb_cnt = get_leb_cnt(c, cnt);
697 dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt);
698 if (!leb_cnt)
699 return 0;
700 c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS);
701 if (!c->ilebs)
702 return -ENOMEM;
703 for (i = 0; i < leb_cnt; i++) {
704 lnum = ubifs_find_free_leb_for_idx(c);
705 if (lnum < 0)
706 return lnum;
707 c->ilebs[c->ileb_cnt++] = lnum;
708 dbg_cmt("LEB %d", lnum);
709 }
710 if (dbg_force_in_the_gaps())
711 return -ENOSPC;
712 return 0;
713}
714
715/**
716 * free_unused_idx_lebs - free unused LEBs that were allocated for the commit.
717 * @c: UBIFS file-system description object
718 *
719 * It is possible that we allocate more empty LEBs for the commit than we need.
720 * This functions frees the surplus.
721 *
722 * This function returns %0 on success and a negative error code on failure.
723 */
724static int free_unused_idx_lebs(struct ubifs_info *c)
725{
726 int i, err = 0, lnum, er;
727
728 for (i = c->ileb_nxt; i < c->ileb_cnt; i++) {
729 lnum = c->ilebs[i];
730 dbg_cmt("LEB %d", lnum);
731 er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
732 LPROPS_INDEX | LPROPS_TAKEN, 0);
733 if (!err)
734 err = er;
735 }
736 return err;
737}
738
739/**
740 * free_idx_lebs - free unused LEBs after commit end.
741 * @c: UBIFS file-system description object
742 *
743 * This function returns %0 on success and a negative error code on failure.
744 */
745static int free_idx_lebs(struct ubifs_info *c)
746{
747 int err;
748
749 err = free_unused_idx_lebs(c);
750 kfree(c->ilebs);
751 c->ilebs = NULL;
752 return err;
753}
754
755/**
756 * ubifs_tnc_start_commit - start TNC commit.
757 * @c: UBIFS file-system description object
758 * @zroot: new index root position is returned here
759 *
760 * This function prepares the list of indexing nodes to commit and lays out
761 * their positions on flash. If there is not enough free space it uses the
762 * in-gap commit method. Returns zero in case of success and a negative error
763 * code in case of failure.
764 */
765int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot)
766{
767 int err = 0, cnt;
768
769 mutex_lock(&c->tnc_mutex);
770 err = dbg_check_tnc(c, 1);
771 if (err)
772 goto out;
773 cnt = get_znodes_to_commit(c);
774 if (cnt != 0) {
775 int no_space = 0;
776
777 err = alloc_idx_lebs(c, cnt);
778 if (err == -ENOSPC)
779 no_space = 1;
780 else if (err)
781 goto out_free;
782 err = layout_commit(c, no_space, cnt);
783 if (err)
784 goto out_free;
785 ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0);
786 err = free_unused_idx_lebs(c);
787 if (err)
788 goto out;
789 }
790 destroy_old_idx(c);
791 memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch));
792
793 err = ubifs_save_dirty_idx_lnums(c);
794 if (err)
795 goto out;
796
797 spin_lock(&c->space_lock);
798 /*
799 * Although we have not finished committing yet, update size of the
800 * committed index ('c->old_idx_sz') and zero out the index growth
801 * budget. It is OK to do this now, because we've reserved all the
802 * space which is needed to commit the index, and it is save for the
803 * budgeting subsystem to assume the index is already committed,
804 * even though it is not.
805 */
806 c->old_idx_sz = c->calc_idx_sz;
807 c->budg_uncommitted_idx = 0;
808 spin_unlock(&c->space_lock);
809 mutex_unlock(&c->tnc_mutex);
810
811 dbg_cmt("number of index LEBs %d", c->lst.idx_lebs);
812 dbg_cmt("size of index %llu", c->calc_idx_sz);
813 return err;
814
815out_free:
816 free_idx_lebs(c);
817out:
818 mutex_unlock(&c->tnc_mutex);
819 return err;
820}
821
822/**
823 * write_index - write index nodes.
824 * @c: UBIFS file-system description object
825 *
826 * This function writes the index nodes whose positions were laid out in the
827 * layout_in_empty_space function.
828 */
829static int write_index(struct ubifs_info *c)
830{
831 struct ubifs_idx_node *idx;
832 struct ubifs_znode *znode, *cnext;
833 int i, lnum, offs, len, next_len, buf_len, buf_offs, used;
834 int avail, wlen, err, lnum_pos = 0;
835
836 cnext = c->enext;
837 if (!cnext)
838 return 0;
839
840 /*
841 * Always write index nodes to the index head so that index nodes and
842 * other types of nodes are never mixed in the same erase block.
843 */
844 lnum = c->ihead_lnum;
845 buf_offs = c->ihead_offs;
846
847 /* Allocate commit buffer */
848 buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size);
849 used = 0;
850 avail = buf_len;
851
852 /* Ensure there is enough room for first write */
853 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
854 if (buf_offs + next_len > c->leb_size) {
855 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0,
856 LPROPS_TAKEN);
857 if (err)
858 return err;
859 lnum = -1;
860 }
861
862 while (1) {
863 cond_resched();
864
865 znode = cnext;
866 idx = c->cbuf + used;
867
868 /* Make index node */
869 idx->ch.node_type = UBIFS_IDX_NODE;
870 idx->child_cnt = cpu_to_le16(znode->child_cnt);
871 idx->level = cpu_to_le16(znode->level);
872 for (i = 0; i < znode->child_cnt; i++) {
873 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
874 struct ubifs_zbranch *zbr = &znode->zbranch[i];
875
876 key_write_idx(c, &zbr->key, &br->key);
877 br->lnum = cpu_to_le32(zbr->lnum);
878 br->offs = cpu_to_le32(zbr->offs);
879 br->len = cpu_to_le32(zbr->len);
880 if (!zbr->lnum || !zbr->len) {
881 ubifs_err("bad ref in znode");
882 dbg_dump_znode(c, znode);
883 if (zbr->znode)
884 dbg_dump_znode(c, zbr->znode);
885 }
886 }
887 len = ubifs_idx_node_sz(c, znode->child_cnt);
888 ubifs_prepare_node(c, idx, len, 0);
889
890 /* Determine the index node position */
891 if (lnum == -1) {
892 lnum = c->ilebs[lnum_pos++];
893 buf_offs = 0;
894 used = 0;
895 avail = buf_len;
896 }
897 offs = buf_offs + used;
898
899#ifdef CONFIG_UBIFS_FS_DEBUG
900 if (lnum != znode->lnum || offs != znode->offs ||
901 len != znode->len) {
902 ubifs_err("inconsistent znode posn");
903 return -EINVAL;
904 }
905#endif
906
907 /* Grab some stuff from znode while we still can */
908 cnext = znode->cnext;
909
910 ubifs_assert(ubifs_zn_dirty(znode));
911 ubifs_assert(test_bit(COW_ZNODE, &znode->flags));
912
913 /*
914 * It is important that other threads should see %DIRTY_ZNODE
915 * flag cleared before %COW_ZNODE. Specifically, it matters in
916 * the 'dirty_cow_znode()' function. This is the reason for the
917 * first barrier. Also, we want the bit changes to be seen to
918 * other threads ASAP, to avoid unnecesarry copying, which is
919 * the reason for the second barrier.
920 */
921 clear_bit(DIRTY_ZNODE, &znode->flags);
922 smp_mb__before_clear_bit();
923 clear_bit(COW_ZNODE, &znode->flags);
924 smp_mb__after_clear_bit();
925
926 /* Do not access znode from this point on */
927
928 /* Update buffer positions */
929 wlen = used + len;
930 used += ALIGN(len, 8);
931 avail -= ALIGN(len, 8);
932
933 /*
934 * Calculate the next index node length to see if there is
935 * enough room for it
936 */
937 if (cnext == c->cnext)
938 next_len = 0;
939 else
940 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
941
942 if (c->min_io_size == 1) {
943 /*
944 * Write the prepared index node immediately if there is
945 * no minimum IO size
946 */
947 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs,
948 wlen, UBI_SHORTTERM);
949 if (err)
950 return err;
951 buf_offs += ALIGN(wlen, 8);
952 if (next_len) {
953 used = 0;
954 avail = buf_len;
955 if (buf_offs + next_len > c->leb_size) {
956 err = ubifs_update_one_lp(c, lnum,
957 LPROPS_NC, 0, 0, LPROPS_TAKEN);
958 if (err)
959 return err;
960 lnum = -1;
961 }
962 continue;
963 }
964 } else {
965 int blen, nxt_offs = buf_offs + used + next_len;
966
967 if (next_len && nxt_offs <= c->leb_size) {
968 if (avail > 0)
969 continue;
970 else
971 blen = buf_len;
972 } else {
973 wlen = ALIGN(wlen, 8);
974 blen = ALIGN(wlen, c->min_io_size);
975 ubifs_pad(c, c->cbuf + wlen, blen - wlen);
976 }
977 /*
978 * The buffer is full or there are no more znodes
979 * to do
980 */
981 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs,
982 blen, UBI_SHORTTERM);
983 if (err)
984 return err;
985 buf_offs += blen;
986 if (next_len) {
987 if (nxt_offs > c->leb_size) {
988 err = ubifs_update_one_lp(c, lnum,
989 LPROPS_NC, 0, 0, LPROPS_TAKEN);
990 if (err)
991 return err;
992 lnum = -1;
993 }
994 used -= blen;
995 if (used < 0)
996 used = 0;
997 avail = buf_len - used;
998 memmove(c->cbuf, c->cbuf + blen, used);
999 continue;
1000 }
1001 }
1002 break;
1003 }
1004
1005#ifdef CONFIG_UBIFS_FS_DEBUG
1006 if (lnum != c->new_ihead_lnum || buf_offs != c->new_ihead_offs) {
1007 ubifs_err("inconsistent ihead");
1008 return -EINVAL;
1009 }
1010#endif
1011
1012 c->ihead_lnum = lnum;
1013 c->ihead_offs = buf_offs;
1014
1015 return 0;
1016}
1017
1018/**
1019 * free_obsolete_znodes - free obsolete znodes.
1020 * @c: UBIFS file-system description object
1021 *
1022 * At the end of commit end, obsolete znodes are freed.
1023 */
1024static void free_obsolete_znodes(struct ubifs_info *c)
1025{
1026 struct ubifs_znode *znode, *cnext;
1027
1028 cnext = c->cnext;
1029 do {
1030 znode = cnext;
1031 cnext = znode->cnext;
1032 if (test_bit(OBSOLETE_ZNODE, &znode->flags))
1033 kfree(znode);
1034 else {
1035 znode->cnext = NULL;
1036 atomic_long_inc(&c->clean_zn_cnt);
1037 atomic_long_inc(&ubifs_clean_zn_cnt);
1038 }
1039 } while (cnext != c->cnext);
1040}
1041
1042/**
1043 * return_gap_lebs - return LEBs used by the in-gap commit method.
1044 * @c: UBIFS file-system description object
1045 *
1046 * This function clears the "taken" flag for the LEBs which were used by the
1047 * "commit in-the-gaps" method.
1048 */
1049static int return_gap_lebs(struct ubifs_info *c)
1050{
1051 int *p, err;
1052
1053 if (!c->gap_lebs)
1054 return 0;
1055
1056 dbg_cmt("");
1057 for (p = c->gap_lebs; *p != -1; p++) {
1058 err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0,
1059 LPROPS_TAKEN, 0);
1060 if (err)
1061 return err;
1062 }
1063
1064 kfree(c->gap_lebs);
1065 c->gap_lebs = NULL;
1066 return 0;
1067}
1068
1069/**
1070 * ubifs_tnc_end_commit - update the TNC for commit end.
1071 * @c: UBIFS file-system description object
1072 *
1073 * Write the dirty znodes.
1074 */
1075int ubifs_tnc_end_commit(struct ubifs_info *c)
1076{
1077 int err;
1078
1079 if (!c->cnext)
1080 return 0;
1081
1082 err = return_gap_lebs(c);
1083 if (err)
1084 return err;
1085
1086 err = write_index(c);
1087 if (err)
1088 return err;
1089
1090 mutex_lock(&c->tnc_mutex);
1091
1092 dbg_cmt("TNC height is %d", c->zroot.znode->level + 1);
1093
1094 free_obsolete_znodes(c);
1095
1096 c->cnext = NULL;
1097 kfree(c->ilebs);
1098 c->ilebs = NULL;
1099
1100 mutex_unlock(&c->tnc_mutex);
1101
1102 return 0;
1103}
generated by cgit v1.2.2 (git 2.25.0) at 2025-12-08 08:26:36 -0500