blob: 53288e5d604e92bd5584b1a3595565261a1c2c81 [file] [log] [blame]
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
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 */
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300248 sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300249 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;
Artem Bityutskiy0010f182008-07-25 16:39:44 +0300375 if (err != -ENOSPC) {
376 kfree(c->gap_lebs);
377 c->gap_lebs = NULL;
378 return err;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300379 }
Artem Bityutskiy0010f182008-07-25 16:39:44 +0300380 if (!dbg_force_in_the_gaps_enabled) {
381 /*
382 * Do not print scary warnings if the debugging
383 * option which forces in-the-gaps is enabled.
384 */
385 ubifs_err("out of space");
386 spin_lock(&c->space_lock);
387 dbg_dump_budg(c);
388 spin_unlock(&c->space_lock);
389 dbg_dump_lprops(c);
390 }
391 /* Try to commit anyway */
392 err = 0;
393 break;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300394 }
395 p++;
396 cnt -= written;
397 leb_needed_cnt = get_leb_cnt(c, cnt);
398 dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
399 leb_needed_cnt, c->ileb_cnt);
400 } while (leb_needed_cnt > c->ileb_cnt);
401
402 *p = -1;
403 return 0;
404}
405
406/**
407 * layout_in_empty_space - layout index nodes in empty space.
408 * @c: UBIFS file-system description object
409 *
410 * This function lays out new index nodes for dirty znodes using empty LEBs.
411 *
412 * This function returns %0 on success and a negative error code on failure.
413 */
414static int layout_in_empty_space(struct ubifs_info *c)
415{
416 struct ubifs_znode *znode, *cnext, *zp;
417 int lnum, offs, len, next_len, buf_len, buf_offs, used, avail;
418 int wlen, blen, err;
419
420 cnext = c->enext;
421 if (!cnext)
422 return 0;
423
424 lnum = c->ihead_lnum;
425 buf_offs = c->ihead_offs;
426
427 buf_len = ubifs_idx_node_sz(c, c->fanout);
428 buf_len = ALIGN(buf_len, c->min_io_size);
429 used = 0;
430 avail = buf_len;
431
432 /* Ensure there is enough room for first write */
433 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
434 if (buf_offs + next_len > c->leb_size)
435 lnum = -1;
436
437 while (1) {
438 znode = cnext;
439
440 len = ubifs_idx_node_sz(c, znode->child_cnt);
441
442 /* Determine the index node position */
443 if (lnum == -1) {
444 if (c->ileb_nxt >= c->ileb_cnt) {
445 ubifs_err("out of space");
446 return -ENOSPC;
447 }
448 lnum = c->ilebs[c->ileb_nxt++];
449 buf_offs = 0;
450 used = 0;
451 avail = buf_len;
452 }
453
454 offs = buf_offs + used;
455
456#ifdef CONFIG_UBIFS_FS_DEBUG
457 znode->lnum = lnum;
458 znode->offs = offs;
459 znode->len = len;
460#endif
461
462 /* Update the parent */
463 zp = znode->parent;
464 if (zp) {
465 struct ubifs_zbranch *zbr;
466 int i;
467
468 i = znode->iip;
469 zbr = &zp->zbranch[i];
470 zbr->lnum = lnum;
471 zbr->offs = offs;
472 zbr->len = len;
473 } else {
474 c->zroot.lnum = lnum;
475 c->zroot.offs = offs;
476 c->zroot.len = len;
477 }
478 c->calc_idx_sz += ALIGN(len, 8);
479
480 /*
481 * Once lprops is updated, we can decrease the dirty znode count
482 * but it is easier to just do it here.
483 */
484 atomic_long_dec(&c->dirty_zn_cnt);
485
486 /*
487 * Calculate the next index node length to see if there is
488 * enough room for it
489 */
490 cnext = znode->cnext;
491 if (cnext == c->cnext)
492 next_len = 0;
493 else
494 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
495
496 if (c->min_io_size == 1) {
497 buf_offs += ALIGN(len, 8);
498 if (next_len) {
499 if (buf_offs + next_len <= c->leb_size)
500 continue;
501 err = ubifs_update_one_lp(c, lnum, 0,
502 c->leb_size - buf_offs, 0, 0);
503 if (err)
504 return err;
505 lnum = -1;
506 continue;
507 }
508 err = ubifs_update_one_lp(c, lnum,
509 c->leb_size - buf_offs, 0, 0, 0);
510 if (err)
511 return err;
512 break;
513 }
514
515 /* Update buffer positions */
516 wlen = used + len;
517 used += ALIGN(len, 8);
518 avail -= ALIGN(len, 8);
519
520 if (next_len != 0 &&
521 buf_offs + used + next_len <= c->leb_size &&
522 avail > 0)
523 continue;
524
525 if (avail <= 0 && next_len &&
526 buf_offs + used + next_len <= c->leb_size)
527 blen = buf_len;
528 else
529 blen = ALIGN(wlen, c->min_io_size);
530
531 /* The buffer is full or there are no more znodes to do */
532 buf_offs += blen;
533 if (next_len) {
534 if (buf_offs + next_len > c->leb_size) {
535 err = ubifs_update_one_lp(c, lnum,
536 c->leb_size - buf_offs, blen - used,
537 0, 0);
538 if (err)
539 return err;
540 lnum = -1;
541 }
542 used -= blen;
543 if (used < 0)
544 used = 0;
545 avail = buf_len - used;
546 continue;
547 }
548 err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs,
549 blen - used, 0, 0);
550 if (err)
551 return err;
552 break;
553 }
554
555#ifdef CONFIG_UBIFS_FS_DEBUG
Artem Bityutskiy17c2f9f2008-10-17 13:31:39 +0300556 c->dbg->new_ihead_lnum = lnum;
557 c->dbg->new_ihead_offs = buf_offs;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300558#endif
559
560 return 0;
561}
562
563/**
564 * layout_commit - determine positions of index nodes to commit.
565 * @c: UBIFS file-system description object
566 * @no_space: indicates that insufficient empty LEBs were allocated
567 * @cnt: number of znodes to commit
568 *
569 * Calculate and update the positions of index nodes to commit. If there were
570 * an insufficient number of empty LEBs allocated, then index nodes are placed
571 * into the gaps created by obsolete index nodes in non-empty index LEBs. For
572 * this purpose, an obsolete index node is one that was not in the index as at
573 * the end of the last commit. To write "in-the-gaps" requires that those index
574 * LEBs are updated atomically in-place.
575 */
576static int layout_commit(struct ubifs_info *c, int no_space, int cnt)
577{
578 int err;
579
580 if (no_space) {
581 err = layout_in_gaps(c, cnt);
582 if (err)
583 return err;
584 }
585 err = layout_in_empty_space(c);
586 return err;
587}
588
589/**
590 * find_first_dirty - find first dirty znode.
591 * @znode: znode to begin searching from
592 */
593static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode)
594{
595 int i, cont;
596
597 if (!znode)
598 return NULL;
599
600 while (1) {
601 if (znode->level == 0) {
602 if (ubifs_zn_dirty(znode))
603 return znode;
604 return NULL;
605 }
606 cont = 0;
607 for (i = 0; i < znode->child_cnt; i++) {
608 struct ubifs_zbranch *zbr = &znode->zbranch[i];
609
610 if (zbr->znode && ubifs_zn_dirty(zbr->znode)) {
611 znode = zbr->znode;
612 cont = 1;
613 break;
614 }
615 }
616 if (!cont) {
617 if (ubifs_zn_dirty(znode))
618 return znode;
619 return NULL;
620 }
621 }
622}
623
624/**
625 * find_next_dirty - find next dirty znode.
626 * @znode: znode to begin searching from
627 */
628static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode)
629{
630 int n = znode->iip + 1;
631
632 znode = znode->parent;
633 if (!znode)
634 return NULL;
635 for (; n < znode->child_cnt; n++) {
636 struct ubifs_zbranch *zbr = &znode->zbranch[n];
637
638 if (zbr->znode && ubifs_zn_dirty(zbr->znode))
639 return find_first_dirty(zbr->znode);
640 }
641 return znode;
642}
643
644/**
645 * get_znodes_to_commit - create list of dirty znodes to commit.
646 * @c: UBIFS file-system description object
647 *
648 * This function returns the number of znodes to commit.
649 */
650static int get_znodes_to_commit(struct ubifs_info *c)
651{
652 struct ubifs_znode *znode, *cnext;
653 int cnt = 0;
654
655 c->cnext = find_first_dirty(c->zroot.znode);
656 znode = c->enext = c->cnext;
657 if (!znode) {
658 dbg_cmt("no znodes to commit");
659 return 0;
660 }
661 cnt += 1;
662 while (1) {
663 ubifs_assert(!test_bit(COW_ZNODE, &znode->flags));
664 __set_bit(COW_ZNODE, &znode->flags);
665 znode->alt = 0;
666 cnext = find_next_dirty(znode);
667 if (!cnext) {
668 znode->cnext = c->cnext;
669 break;
670 }
671 znode->cnext = cnext;
672 znode = cnext;
673 cnt += 1;
674 }
675 dbg_cmt("committing %d znodes", cnt);
676 ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt));
677 return cnt;
678}
679
680/**
681 * alloc_idx_lebs - allocate empty LEBs to be used to commit.
682 * @c: UBIFS file-system description object
683 * @cnt: number of znodes to commit
684 *
685 * This function returns %-ENOSPC if it cannot allocate a sufficient number of
686 * empty LEBs. %0 is returned on success, otherwise a negative error code
687 * is returned.
688 */
689static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
690{
691 int i, leb_cnt, lnum;
692
693 c->ileb_cnt = 0;
694 c->ileb_nxt = 0;
695 leb_cnt = get_leb_cnt(c, cnt);
696 dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt);
697 if (!leb_cnt)
698 return 0;
699 c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS);
700 if (!c->ilebs)
701 return -ENOMEM;
702 for (i = 0; i < leb_cnt; i++) {
703 lnum = ubifs_find_free_leb_for_idx(c);
704 if (lnum < 0)
705 return lnum;
706 c->ilebs[c->ileb_cnt++] = lnum;
707 dbg_cmt("LEB %d", lnum);
708 }
709 if (dbg_force_in_the_gaps())
710 return -ENOSPC;
711 return 0;
712}
713
714/**
715 * free_unused_idx_lebs - free unused LEBs that were allocated for the commit.
716 * @c: UBIFS file-system description object
717 *
718 * It is possible that we allocate more empty LEBs for the commit than we need.
719 * This functions frees the surplus.
720 *
721 * This function returns %0 on success and a negative error code on failure.
722 */
723static int free_unused_idx_lebs(struct ubifs_info *c)
724{
725 int i, err = 0, lnum, er;
726
727 for (i = c->ileb_nxt; i < c->ileb_cnt; i++) {
728 lnum = c->ilebs[i];
729 dbg_cmt("LEB %d", lnum);
730 er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
731 LPROPS_INDEX | LPROPS_TAKEN, 0);
732 if (!err)
733 err = er;
734 }
735 return err;
736}
737
738/**
739 * free_idx_lebs - free unused LEBs after commit end.
740 * @c: UBIFS file-system description object
741 *
742 * This function returns %0 on success and a negative error code on failure.
743 */
744static int free_idx_lebs(struct ubifs_info *c)
745{
746 int err;
747
748 err = free_unused_idx_lebs(c);
749 kfree(c->ilebs);
750 c->ilebs = NULL;
751 return err;
752}
753
754/**
755 * ubifs_tnc_start_commit - start TNC commit.
756 * @c: UBIFS file-system description object
757 * @zroot: new index root position is returned here
758 *
759 * This function prepares the list of indexing nodes to commit and lays out
760 * their positions on flash. If there is not enough free space it uses the
761 * in-gap commit method. Returns zero in case of success and a negative error
762 * code in case of failure.
763 */
764int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot)
765{
766 int err = 0, cnt;
767
768 mutex_lock(&c->tnc_mutex);
769 err = dbg_check_tnc(c, 1);
770 if (err)
771 goto out;
772 cnt = get_znodes_to_commit(c);
773 if (cnt != 0) {
774 int no_space = 0;
775
776 err = alloc_idx_lebs(c, cnt);
777 if (err == -ENOSPC)
778 no_space = 1;
779 else if (err)
780 goto out_free;
781 err = layout_commit(c, no_space, cnt);
782 if (err)
783 goto out_free;
784 ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0);
785 err = free_unused_idx_lebs(c);
786 if (err)
787 goto out;
788 }
789 destroy_old_idx(c);
790 memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch));
791
792 err = ubifs_save_dirty_idx_lnums(c);
793 if (err)
794 goto out;
795
796 spin_lock(&c->space_lock);
797 /*
798 * Although we have not finished committing yet, update size of the
799 * committed index ('c->old_idx_sz') and zero out the index growth
800 * budget. It is OK to do this now, because we've reserved all the
801 * space which is needed to commit the index, and it is save for the
802 * budgeting subsystem to assume the index is already committed,
803 * even though it is not.
804 */
Artem Bityutskiy650ed502008-12-22 11:09:04 +0200805 ubifs_assert(c->min_idx_lebs == ubifs_calc_min_idx_lebs(c));
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300806 c->old_idx_sz = c->calc_idx_sz;
807 c->budg_uncommitted_idx = 0;
Artem Bityutskiy650ed502008-12-22 11:09:04 +0200808 c->min_idx_lebs = ubifs_calc_min_idx_lebs(c);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300809 spin_unlock(&c->space_lock);
810 mutex_unlock(&c->tnc_mutex);
811
812 dbg_cmt("number of index LEBs %d", c->lst.idx_lebs);
813 dbg_cmt("size of index %llu", c->calc_idx_sz);
814 return err;
815
816out_free:
817 free_idx_lebs(c);
818out:
819 mutex_unlock(&c->tnc_mutex);
820 return err;
821}
822
823/**
824 * write_index - write index nodes.
825 * @c: UBIFS file-system description object
826 *
827 * This function writes the index nodes whose positions were laid out in the
828 * layout_in_empty_space function.
829 */
830static int write_index(struct ubifs_info *c)
831{
832 struct ubifs_idx_node *idx;
833 struct ubifs_znode *znode, *cnext;
834 int i, lnum, offs, len, next_len, buf_len, buf_offs, used;
835 int avail, wlen, err, lnum_pos = 0;
836
837 cnext = c->enext;
838 if (!cnext)
839 return 0;
840
841 /*
842 * Always write index nodes to the index head so that index nodes and
843 * other types of nodes are never mixed in the same erase block.
844 */
845 lnum = c->ihead_lnum;
846 buf_offs = c->ihead_offs;
847
848 /* Allocate commit buffer */
849 buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size);
850 used = 0;
851 avail = buf_len;
852
853 /* Ensure there is enough room for first write */
854 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
855 if (buf_offs + next_len > c->leb_size) {
856 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0,
857 LPROPS_TAKEN);
858 if (err)
859 return err;
860 lnum = -1;
861 }
862
863 while (1) {
864 cond_resched();
865
866 znode = cnext;
867 idx = c->cbuf + used;
868
869 /* Make index node */
870 idx->ch.node_type = UBIFS_IDX_NODE;
871 idx->child_cnt = cpu_to_le16(znode->child_cnt);
872 idx->level = cpu_to_le16(znode->level);
873 for (i = 0; i < znode->child_cnt; i++) {
874 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
875 struct ubifs_zbranch *zbr = &znode->zbranch[i];
876
877 key_write_idx(c, &zbr->key, &br->key);
878 br->lnum = cpu_to_le32(zbr->lnum);
879 br->offs = cpu_to_le32(zbr->offs);
880 br->len = cpu_to_le32(zbr->len);
881 if (!zbr->lnum || !zbr->len) {
882 ubifs_err("bad ref in znode");
883 dbg_dump_znode(c, znode);
884 if (zbr->znode)
885 dbg_dump_znode(c, zbr->znode);
886 }
887 }
888 len = ubifs_idx_node_sz(c, znode->child_cnt);
889 ubifs_prepare_node(c, idx, len, 0);
890
891 /* Determine the index node position */
892 if (lnum == -1) {
893 lnum = c->ilebs[lnum_pos++];
894 buf_offs = 0;
895 used = 0;
896 avail = buf_len;
897 }
898 offs = buf_offs + used;
899
900#ifdef CONFIG_UBIFS_FS_DEBUG
901 if (lnum != znode->lnum || offs != znode->offs ||
902 len != znode->len) {
903 ubifs_err("inconsistent znode posn");
904 return -EINVAL;
905 }
906#endif
907
908 /* Grab some stuff from znode while we still can */
909 cnext = znode->cnext;
910
911 ubifs_assert(ubifs_zn_dirty(znode));
912 ubifs_assert(test_bit(COW_ZNODE, &znode->flags));
913
914 /*
915 * It is important that other threads should see %DIRTY_ZNODE
916 * flag cleared before %COW_ZNODE. Specifically, it matters in
917 * the 'dirty_cow_znode()' function. This is the reason for the
918 * first barrier. Also, we want the bit changes to be seen to
919 * other threads ASAP, to avoid unnecesarry copying, which is
920 * the reason for the second barrier.
921 */
922 clear_bit(DIRTY_ZNODE, &znode->flags);
923 smp_mb__before_clear_bit();
924 clear_bit(COW_ZNODE, &znode->flags);
925 smp_mb__after_clear_bit();
926
927 /* Do not access znode from this point on */
928
929 /* Update buffer positions */
930 wlen = used + len;
931 used += ALIGN(len, 8);
932 avail -= ALIGN(len, 8);
933
934 /*
935 * Calculate the next index node length to see if there is
936 * enough room for it
937 */
938 if (cnext == c->cnext)
939 next_len = 0;
940 else
941 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
942
943 if (c->min_io_size == 1) {
944 /*
945 * Write the prepared index node immediately if there is
946 * no minimum IO size
947 */
948 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs,
949 wlen, UBI_SHORTTERM);
950 if (err)
951 return err;
952 buf_offs += ALIGN(wlen, 8);
953 if (next_len) {
954 used = 0;
955 avail = buf_len;
956 if (buf_offs + next_len > c->leb_size) {
957 err = ubifs_update_one_lp(c, lnum,
958 LPROPS_NC, 0, 0, LPROPS_TAKEN);
959 if (err)
960 return err;
961 lnum = -1;
962 }
963 continue;
964 }
965 } else {
966 int blen, nxt_offs = buf_offs + used + next_len;
967
968 if (next_len && nxt_offs <= c->leb_size) {
969 if (avail > 0)
970 continue;
971 else
972 blen = buf_len;
973 } else {
974 wlen = ALIGN(wlen, 8);
975 blen = ALIGN(wlen, c->min_io_size);
976 ubifs_pad(c, c->cbuf + wlen, blen - wlen);
977 }
978 /*
979 * The buffer is full or there are no more znodes
980 * to do
981 */
982 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs,
983 blen, UBI_SHORTTERM);
984 if (err)
985 return err;
986 buf_offs += blen;
987 if (next_len) {
988 if (nxt_offs > c->leb_size) {
989 err = ubifs_update_one_lp(c, lnum,
990 LPROPS_NC, 0, 0, LPROPS_TAKEN);
991 if (err)
992 return err;
993 lnum = -1;
994 }
995 used -= blen;
996 if (used < 0)
997 used = 0;
998 avail = buf_len - used;
999 memmove(c->cbuf, c->cbuf + blen, used);
1000 continue;
1001 }
1002 }
1003 break;
1004 }
1005
1006#ifdef CONFIG_UBIFS_FS_DEBUG
Artem Bityutskiy17c2f9f2008-10-17 13:31:39 +03001007 if (lnum != c->dbg->new_ihead_lnum ||
1008 buf_offs != c->dbg->new_ihead_offs) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001009 ubifs_err("inconsistent ihead");
1010 return -EINVAL;
1011 }
1012#endif
1013
1014 c->ihead_lnum = lnum;
1015 c->ihead_offs = buf_offs;
1016
1017 return 0;
1018}
1019
1020/**
1021 * free_obsolete_znodes - free obsolete znodes.
1022 * @c: UBIFS file-system description object
1023 *
1024 * At the end of commit end, obsolete znodes are freed.
1025 */
1026static void free_obsolete_znodes(struct ubifs_info *c)
1027{
1028 struct ubifs_znode *znode, *cnext;
1029
1030 cnext = c->cnext;
1031 do {
1032 znode = cnext;
1033 cnext = znode->cnext;
1034 if (test_bit(OBSOLETE_ZNODE, &znode->flags))
1035 kfree(znode);
1036 else {
1037 znode->cnext = NULL;
1038 atomic_long_inc(&c->clean_zn_cnt);
1039 atomic_long_inc(&ubifs_clean_zn_cnt);
1040 }
1041 } while (cnext != c->cnext);
1042}
1043
1044/**
1045 * return_gap_lebs - return LEBs used by the in-gap commit method.
1046 * @c: UBIFS file-system description object
1047 *
1048 * This function clears the "taken" flag for the LEBs which were used by the
1049 * "commit in-the-gaps" method.
1050 */
1051static int return_gap_lebs(struct ubifs_info *c)
1052{
1053 int *p, err;
1054
1055 if (!c->gap_lebs)
1056 return 0;
1057
1058 dbg_cmt("");
1059 for (p = c->gap_lebs; *p != -1; p++) {
1060 err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0,
1061 LPROPS_TAKEN, 0);
1062 if (err)
1063 return err;
1064 }
1065
1066 kfree(c->gap_lebs);
1067 c->gap_lebs = NULL;
1068 return 0;
1069}
1070
1071/**
1072 * ubifs_tnc_end_commit - update the TNC for commit end.
1073 * @c: UBIFS file-system description object
1074 *
1075 * Write the dirty znodes.
1076 */
1077int ubifs_tnc_end_commit(struct ubifs_info *c)
1078{
1079 int err;
1080
1081 if (!c->cnext)
1082 return 0;
1083
1084 err = return_gap_lebs(c);
1085 if (err)
1086 return err;
1087
1088 err = write_index(c);
1089 if (err)
1090 return err;
1091
1092 mutex_lock(&c->tnc_mutex);
1093
1094 dbg_cmt("TNC height is %d", c->zroot.znode->level + 1);
1095
1096 free_obsolete_znodes(c);
1097
1098 c->cnext = NULL;
1099 kfree(c->ilebs);
1100 c->ilebs = NULL;
1101
1102 mutex_unlock(&c->tnc_mutex);
1103
1104 return 0;
1105}