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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 <linux/random.h>
26#include "ubifs.h"
27
28/**
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
36 */
37static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx,
38 struct ubifs_znode *znode, int lnum, int offs, int len)
39{
40 struct ubifs_znode *zp;
41 int i, err;
42
43 /* Make index node */
44 idx->ch.node_type = UBIFS_IDX_NODE;
45 idx->child_cnt = cpu_to_le16(znode->child_cnt);
46 idx->level = cpu_to_le16(znode->level);
47 for (i = 0; i < znode->child_cnt; i++) {
48 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
49 struct ubifs_zbranch *zbr = &znode->zbranch[i];
50
51 key_write_idx(c, &zbr->key, &br->key);
52 br->lnum = cpu_to_le32(zbr->lnum);
53 br->offs = cpu_to_le32(zbr->offs);
54 br->len = cpu_to_le32(zbr->len);
55 if (!zbr->lnum || !zbr->len) {
56 ubifs_err(c, "bad ref in znode");
57 ubifs_dump_znode(c, znode);
58 if (zbr->znode)
59 ubifs_dump_znode(c, zbr->znode);
60 }
61 }
62 ubifs_prepare_node(c, idx, len, 0);
63
64 znode->lnum = lnum;
65 znode->offs = offs;
66 znode->len = len;
67
68 err = insert_old_idx_znode(c, znode);
69
70 /* Update the parent */
71 zp = znode->parent;
72 if (zp) {
73 struct ubifs_zbranch *zbr;
74
75 zbr = &zp->zbranch[znode->iip];
76 zbr->lnum = lnum;
77 zbr->offs = offs;
78 zbr->len = len;
79 } else {
80 c->zroot.lnum = lnum;
81 c->zroot.offs = offs;
82 c->zroot.len = len;
83 }
84 c->calc_idx_sz += ALIGN(len, 8);
85
86 atomic_long_dec(&c->dirty_zn_cnt);
87
88 ubifs_assert(ubifs_zn_dirty(znode));
89 ubifs_assert(ubifs_zn_cow(znode));
90
91 /*
92 * Note, unlike 'write_index()' we do not add memory barriers here
93 * because this function is called with @c->tnc_mutex locked.
94 */
95 __clear_bit(DIRTY_ZNODE, &znode->flags);
96 __clear_bit(COW_ZNODE, &znode->flags);
97
98 return err;
99}
100
101/**
102 * fill_gap - make index nodes in gaps in dirty index LEBs.
103 * @c: UBIFS file-system description object
104 * @lnum: LEB number that gap appears in
105 * @gap_start: offset of start of gap
106 * @gap_end: offset of end of gap
107 * @dirt: adds dirty space to this
108 *
109 * This function returns the number of index nodes written into the gap.
110 */
111static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end,
112 int *dirt)
113{
114 int len, gap_remains, gap_pos, written, pad_len;
115
116 ubifs_assert((gap_start & 7) == 0);
117 ubifs_assert((gap_end & 7) == 0);
118 ubifs_assert(gap_end >= gap_start);
119
120 gap_remains = gap_end - gap_start;
121 if (!gap_remains)
122 return 0;
123 gap_pos = gap_start;
124 written = 0;
125 while (c->enext) {
126 len = ubifs_idx_node_sz(c, c->enext->child_cnt);
127 if (len < gap_remains) {
128 struct ubifs_znode *znode = c->enext;
129 const int alen = ALIGN(len, 8);
130 int err;
131
132 ubifs_assert(alen <= gap_remains);
133 err = make_idx_node(c, c->ileb_buf + gap_pos, znode,
134 lnum, gap_pos, len);
135 if (err)
136 return err;
137 gap_remains -= alen;
138 gap_pos += alen;
139 c->enext = znode->cnext;
140 if (c->enext == c->cnext)
141 c->enext = NULL;
142 written += 1;
143 } else
144 break;
145 }
146 if (gap_end == c->leb_size) {
147 c->ileb_len = ALIGN(gap_pos, c->min_io_size);
148 /* Pad to end of min_io_size */
149 pad_len = c->ileb_len - gap_pos;
150 } else
151 /* Pad to end of gap */
152 pad_len = gap_remains;
153 dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d",
154 lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len);
155 ubifs_pad(c, c->ileb_buf + gap_pos, pad_len);
156 *dirt += pad_len;
157 return written;
158}
159
160/**
161 * find_old_idx - find an index node obsoleted since the last commit start.
162 * @c: UBIFS file-system description object
163 * @lnum: LEB number of obsoleted index node
164 * @offs: offset of obsoleted index node
165 *
166 * Returns %1 if found and %0 otherwise.
167 */
168static int find_old_idx(struct ubifs_info *c, int lnum, int offs)
169{
170 struct ubifs_old_idx *o;
171 struct rb_node *p;
172
173 p = c->old_idx.rb_node;
174 while (p) {
175 o = rb_entry(p, struct ubifs_old_idx, rb);
176 if (lnum < o->lnum)
177 p = p->rb_left;
178 else if (lnum > o->lnum)
179 p = p->rb_right;
180 else if (offs < o->offs)
181 p = p->rb_left;
182 else if (offs > o->offs)
183 p = p->rb_right;
184 else
185 return 1;
186 }
187 return 0;
188}
189
190/**
191 * is_idx_node_in_use - determine if an index node can be overwritten.
192 * @c: UBIFS file-system description object
193 * @key: key of index node
194 * @level: index node level
195 * @lnum: LEB number of index node
196 * @offs: offset of index node
197 *
198 * If @key / @lnum / @offs identify an index node that was not part of the old
199 * index, then this function returns %0 (obsolete). Else if the index node was
200 * part of the old index but is now dirty %1 is returned, else if it is clean %2
201 * is returned. A negative error code is returned on failure.
202 */
203static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
204 int level, int lnum, int offs)
205{
206 int ret;
207
208 ret = is_idx_node_in_tnc(c, key, level, lnum, offs);
209 if (ret < 0)
210 return ret; /* Error code */
211 if (ret == 0)
212 if (find_old_idx(c, lnum, offs))
213 return 1;
214 return ret;
215}
216
217/**
218 * layout_leb_in_gaps - layout index nodes using in-the-gaps method.
219 * @c: UBIFS file-system description object
220 * @p: return LEB number here
221 *
222 * This function lays out new index nodes for dirty znodes using in-the-gaps
223 * method of TNC commit.
224 * This function merely puts the next znode into the next gap, making no attempt
225 * to try to maximise the number of znodes that fit.
226 * This function returns the number of index nodes written into the gaps, or a
227 * negative error code on failure.
228 */
229static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
230{
231 struct ubifs_scan_leb *sleb;
232 struct ubifs_scan_node *snod;
233 int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written;
234
235 tot_written = 0;
236 /* Get an index LEB with lots of obsolete index nodes */
237 lnum = ubifs_find_dirty_idx_leb(c);
238 if (lnum < 0)
239 /*
240 * There also may be dirt in the index head that could be
241 * filled, however we do not check there at present.
242 */
243 return lnum; /* Error code */
244 *p = lnum;
245 dbg_gc("LEB %d", lnum);
246 /*
247 * Scan the index LEB. We use the generic scan for this even though
248 * it is more comprehensive and less efficient than is needed for this
249 * purpose.
250 */
251 sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0);
252 c->ileb_len = 0;
253 if (IS_ERR(sleb))
254 return PTR_ERR(sleb);
255 gap_start = 0;
256 list_for_each_entry(snod, &sleb->nodes, list) {
257 struct ubifs_idx_node *idx;
258 int in_use, level;
259
260 ubifs_assert(snod->type == UBIFS_IDX_NODE);
261 idx = snod->node;
262 key_read(c, ubifs_idx_key(c, idx), &snod->key);
263 level = le16_to_cpu(idx->level);
264 /* Determine if the index node is in use (not obsolete) */
265 in_use = is_idx_node_in_use(c, &snod->key, level, lnum,
266 snod->offs);
267 if (in_use < 0) {
268 ubifs_scan_destroy(sleb);
269 return in_use; /* Error code */
270 }
271 if (in_use) {
272 if (in_use == 1)
273 dirt += ALIGN(snod->len, 8);
274 /*
275 * The obsolete index nodes form gaps that can be
276 * overwritten. This gap has ended because we have
277 * found an index node that is still in use
278 * i.e. not obsolete
279 */
280 gap_end = snod->offs;
281 /* Try to fill gap */
282 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
283 if (written < 0) {
284 ubifs_scan_destroy(sleb);
285 return written; /* Error code */
286 }
287 tot_written += written;
288 gap_start = ALIGN(snod->offs + snod->len, 8);
289 }
290 }
291 ubifs_scan_destroy(sleb);
292 c->ileb_len = c->leb_size;
293 gap_end = c->leb_size;
294 /* Try to fill gap */
295 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
296 if (written < 0)
297 return written; /* Error code */
298 tot_written += written;
299 if (tot_written == 0) {
300 struct ubifs_lprops lp;
301
302 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
303 err = ubifs_read_one_lp(c, lnum, &lp);
304 if (err)
305 return err;
306 if (lp.free == c->leb_size) {
307 /*
308 * We must have snatched this LEB from the idx_gc list
309 * so we need to correct the free and dirty space.
310 */
311 err = ubifs_change_one_lp(c, lnum,
312 c->leb_size - c->ileb_len,
313 dirt, 0, 0, 0);
314 if (err)
315 return err;
316 }
317 return 0;
318 }
319 err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt,
320 0, 0, 0);
321 if (err)
322 return err;
323 err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len);
324 if (err)
325 return err;
326 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
327 return tot_written;
328}
329
330/**
331 * get_leb_cnt - calculate the number of empty LEBs needed to commit.
332 * @c: UBIFS file-system description object
333 * @cnt: number of znodes to commit
334 *
335 * This function returns the number of empty LEBs needed to commit @cnt znodes
336 * to the current index head. The number is not exact and may be more than
337 * needed.
338 */
339static int get_leb_cnt(struct ubifs_info *c, int cnt)
340{
341 int d;
342
343 /* Assume maximum index node size (i.e. overestimate space needed) */
344 cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz;
345 if (cnt < 0)
346 cnt = 0;
347 d = c->leb_size / c->max_idx_node_sz;
348 return DIV_ROUND_UP(cnt, d);
349}
350
351/**
352 * layout_in_gaps - in-the-gaps method of committing TNC.
353 * @c: UBIFS file-system description object
354 * @cnt: number of dirty znodes to commit.
355 *
356 * This function lays out new index nodes for dirty znodes using in-the-gaps
357 * method of TNC commit.
358 *
359 * This function returns %0 on success and a negative error code on failure.
360 */
361static int layout_in_gaps(struct ubifs_info *c, int cnt)
362{
363 int err, leb_needed_cnt, written, *p;
364
365 dbg_gc("%d znodes to write", cnt);
366
367 c->gap_lebs = kmalloc(sizeof(int) * (c->lst.idx_lebs + 1), GFP_NOFS);
368 if (!c->gap_lebs)
369 return -ENOMEM;
370
371 p = c->gap_lebs;
372 do {
373 ubifs_assert(p < c->gap_lebs + sizeof(int) * c->lst.idx_lebs);
374 written = layout_leb_in_gaps(c, p);
375 if (written < 0) {
376 err = written;
377 if (err != -ENOSPC) {
378 kfree(c->gap_lebs);
379 c->gap_lebs = NULL;
380 return err;
381 }
382 if (!dbg_is_chk_index(c)) {
383 /*
384 * Do not print scary warnings if the debugging
385 * option which forces in-the-gaps is enabled.
386 */
387 ubifs_warn(c, "out of space");
388 ubifs_dump_budg(c, &c->bi);
389 ubifs_dump_lprops(c);
390 }
391 /* Try to commit anyway */
392 break;
393 }
394 p++;
395 cnt -= written;
396 leb_needed_cnt = get_leb_cnt(c, cnt);
397 dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
398 leb_needed_cnt, c->ileb_cnt);
399 } while (leb_needed_cnt > c->ileb_cnt);
400
401 *p = -1;
402 return 0;
403}
404
405/**
406 * layout_in_empty_space - layout index nodes in empty space.
407 * @c: UBIFS file-system description object
408 *
409 * This function lays out new index nodes for dirty znodes using empty LEBs.
410 *
411 * This function returns %0 on success and a negative error code on failure.
412 */
413static int layout_in_empty_space(struct ubifs_info *c)
414{
415 struct ubifs_znode *znode, *cnext, *zp;
416 int lnum, offs, len, next_len, buf_len, buf_offs, used, avail;
417 int wlen, blen, err;
418
419 cnext = c->enext;
420 if (!cnext)
421 return 0;
422
423 lnum = c->ihead_lnum;
424 buf_offs = c->ihead_offs;
425
426 buf_len = ubifs_idx_node_sz(c, c->fanout);
427 buf_len = ALIGN(buf_len, c->min_io_size);
428 used = 0;
429 avail = buf_len;
430
431 /* Ensure there is enough room for first write */
432 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
433 if (buf_offs + next_len > c->leb_size)
434 lnum = -1;
435
436 while (1) {
437 znode = cnext;
438
439 len = ubifs_idx_node_sz(c, znode->child_cnt);
440
441 /* Determine the index node position */
442 if (lnum == -1) {
443 if (c->ileb_nxt >= c->ileb_cnt) {
444 ubifs_err(c, "out of space");
445 return -ENOSPC;
446 }
447 lnum = c->ilebs[c->ileb_nxt++];
448 buf_offs = 0;
449 used = 0;
450 avail = buf_len;
451 }
452
453 offs = buf_offs + used;
454
455 znode->lnum = lnum;
456 znode->offs = offs;
457 znode->len = len;
458
459 /* Update the parent */
460 zp = znode->parent;
461 if (zp) {
462 struct ubifs_zbranch *zbr;
463 int i;
464
465 i = znode->iip;
466 zbr = &zp->zbranch[i];
467 zbr->lnum = lnum;
468 zbr->offs = offs;
469 zbr->len = len;
470 } else {
471 c->zroot.lnum = lnum;
472 c->zroot.offs = offs;
473 c->zroot.len = len;
474 }
475 c->calc_idx_sz += ALIGN(len, 8);
476
477 /*
478 * Once lprops is updated, we can decrease the dirty znode count
479 * but it is easier to just do it here.
480 */
481 atomic_long_dec(&c->dirty_zn_cnt);
482
483 /*
484 * Calculate the next index node length to see if there is
485 * enough room for it
486 */
487 cnext = znode->cnext;
488 if (cnext == c->cnext)
489 next_len = 0;
490 else
491 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
492
493 /* Update buffer positions */
494 wlen = used + len;
495 used += ALIGN(len, 8);
496 avail -= ALIGN(len, 8);
497
498 if (next_len != 0 &&
499 buf_offs + used + next_len <= c->leb_size &&
500 avail > 0)
501 continue;
502
503 if (avail <= 0 && next_len &&
504 buf_offs + used + next_len <= c->leb_size)
505 blen = buf_len;
506 else
507 blen = ALIGN(wlen, c->min_io_size);
508
509 /* The buffer is full or there are no more znodes to do */
510 buf_offs += blen;
511 if (next_len) {
512 if (buf_offs + next_len > c->leb_size) {
513 err = ubifs_update_one_lp(c, lnum,
514 c->leb_size - buf_offs, blen - used,
515 0, 0);
516 if (err)
517 return err;
518 lnum = -1;
519 }
520 used -= blen;
521 if (used < 0)
522 used = 0;
523 avail = buf_len - used;
524 continue;
525 }
526 err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs,
527 blen - used, 0, 0);
528 if (err)
529 return err;
530 break;
531 }
532
533 c->dbg->new_ihead_lnum = lnum;
534 c->dbg->new_ihead_offs = buf_offs;
535
536 return 0;
537}
538
539/**
540 * layout_commit - determine positions of index nodes to commit.
541 * @c: UBIFS file-system description object
542 * @no_space: indicates that insufficient empty LEBs were allocated
543 * @cnt: number of znodes to commit
544 *
545 * Calculate and update the positions of index nodes to commit. If there were
546 * an insufficient number of empty LEBs allocated, then index nodes are placed
547 * into the gaps created by obsolete index nodes in non-empty index LEBs. For
548 * this purpose, an obsolete index node is one that was not in the index as at
549 * the end of the last commit. To write "in-the-gaps" requires that those index
550 * LEBs are updated atomically in-place.
551 */
552static int layout_commit(struct ubifs_info *c, int no_space, int cnt)
553{
554 int err;
555
556 if (no_space) {
557 err = layout_in_gaps(c, cnt);
558 if (err)
559 return err;
560 }
561 err = layout_in_empty_space(c);
562 return err;
563}
564
565/**
566 * find_first_dirty - find first dirty znode.
567 * @znode: znode to begin searching from
568 */
569static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode)
570{
571 int i, cont;
572
573 if (!znode)
574 return NULL;
575
576 while (1) {
577 if (znode->level == 0) {
578 if (ubifs_zn_dirty(znode))
579 return znode;
580 return NULL;
581 }
582 cont = 0;
583 for (i = 0; i < znode->child_cnt; i++) {
584 struct ubifs_zbranch *zbr = &znode->zbranch[i];
585
586 if (zbr->znode && ubifs_zn_dirty(zbr->znode)) {
587 znode = zbr->znode;
588 cont = 1;
589 break;
590 }
591 }
592 if (!cont) {
593 if (ubifs_zn_dirty(znode))
594 return znode;
595 return NULL;
596 }
597 }
598}
599
600/**
601 * find_next_dirty - find next dirty znode.
602 * @znode: znode to begin searching from
603 */
604static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode)
605{
606 int n = znode->iip + 1;
607
608 znode = znode->parent;
609 if (!znode)
610 return NULL;
611 for (; n < znode->child_cnt; n++) {
612 struct ubifs_zbranch *zbr = &znode->zbranch[n];
613
614 if (zbr->znode && ubifs_zn_dirty(zbr->znode))
615 return find_first_dirty(zbr->znode);
616 }
617 return znode;
618}
619
620/**
621 * get_znodes_to_commit - create list of dirty znodes to commit.
622 * @c: UBIFS file-system description object
623 *
624 * This function returns the number of znodes to commit.
625 */
626static int get_znodes_to_commit(struct ubifs_info *c)
627{
628 struct ubifs_znode *znode, *cnext;
629 int cnt = 0;
630
631 c->cnext = find_first_dirty(c->zroot.znode);
632 znode = c->enext = c->cnext;
633 if (!znode) {
634 dbg_cmt("no znodes to commit");
635 return 0;
636 }
637 cnt += 1;
638 while (1) {
639 ubifs_assert(!ubifs_zn_cow(znode));
640 __set_bit(COW_ZNODE, &znode->flags);
641 znode->alt = 0;
642 cnext = find_next_dirty(znode);
643 if (!cnext) {
644 znode->cnext = c->cnext;
645 break;
646 }
647 znode->cnext = cnext;
648 znode = cnext;
649 cnt += 1;
650 }
651 dbg_cmt("committing %d znodes", cnt);
652 ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt));
653 return cnt;
654}
655
656/**
657 * alloc_idx_lebs - allocate empty LEBs to be used to commit.
658 * @c: UBIFS file-system description object
659 * @cnt: number of znodes to commit
660 *
661 * This function returns %-ENOSPC if it cannot allocate a sufficient number of
662 * empty LEBs. %0 is returned on success, otherwise a negative error code
663 * is returned.
664 */
665static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
666{
667 int i, leb_cnt, lnum;
668
669 c->ileb_cnt = 0;
670 c->ileb_nxt = 0;
671 leb_cnt = get_leb_cnt(c, cnt);
672 dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt);
673 if (!leb_cnt)
674 return 0;
675 c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS);
676 if (!c->ilebs)
677 return -ENOMEM;
678 for (i = 0; i < leb_cnt; i++) {
679 lnum = ubifs_find_free_leb_for_idx(c);
680 if (lnum < 0)
681 return lnum;
682 c->ilebs[c->ileb_cnt++] = lnum;
683 dbg_cmt("LEB %d", lnum);
684 }
685 if (dbg_is_chk_index(c) && !(prandom_u32() & 7))
686 return -ENOSPC;
687 return 0;
688}
689
690/**
691 * free_unused_idx_lebs - free unused LEBs that were allocated for the commit.
692 * @c: UBIFS file-system description object
693 *
694 * It is possible that we allocate more empty LEBs for the commit than we need.
695 * This functions frees the surplus.
696 *
697 * This function returns %0 on success and a negative error code on failure.
698 */
699static int free_unused_idx_lebs(struct ubifs_info *c)
700{
701 int i, err = 0, lnum, er;
702
703 for (i = c->ileb_nxt; i < c->ileb_cnt; i++) {
704 lnum = c->ilebs[i];
705 dbg_cmt("LEB %d", lnum);
706 er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
707 LPROPS_INDEX | LPROPS_TAKEN, 0);
708 if (!err)
709 err = er;
710 }
711 return err;
712}
713
714/**
715 * free_idx_lebs - free unused LEBs after commit end.
716 * @c: UBIFS file-system description object
717 *
718 * This function returns %0 on success and a negative error code on failure.
719 */
720static int free_idx_lebs(struct ubifs_info *c)
721{
722 int err;
723
724 err = free_unused_idx_lebs(c);
725 kfree(c->ilebs);
726 c->ilebs = NULL;
727 return err;
728}
729
730/**
731 * ubifs_tnc_start_commit - start TNC commit.
732 * @c: UBIFS file-system description object
733 * @zroot: new index root position is returned here
734 *
735 * This function prepares the list of indexing nodes to commit and lays out
736 * their positions on flash. If there is not enough free space it uses the
737 * in-gap commit method. Returns zero in case of success and a negative error
738 * code in case of failure.
739 */
740int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot)
741{
742 int err = 0, cnt;
743
744 mutex_lock(&c->tnc_mutex);
745 err = dbg_check_tnc(c, 1);
746 if (err)
747 goto out;
748 cnt = get_znodes_to_commit(c);
749 if (cnt != 0) {
750 int no_space = 0;
751
752 err = alloc_idx_lebs(c, cnt);
753 if (err == -ENOSPC)
754 no_space = 1;
755 else if (err)
756 goto out_free;
757 err = layout_commit(c, no_space, cnt);
758 if (err)
759 goto out_free;
760 ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0);
761 err = free_unused_idx_lebs(c);
762 if (err)
763 goto out;
764 }
765 destroy_old_idx(c);
766 memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch));
767
768 err = ubifs_save_dirty_idx_lnums(c);
769 if (err)
770 goto out;
771
772 spin_lock(&c->space_lock);
773 /*
774 * Although we have not finished committing yet, update size of the
775 * committed index ('c->bi.old_idx_sz') and zero out the index growth
776 * budget. It is OK to do this now, because we've reserved all the
777 * space which is needed to commit the index, and it is save for the
778 * budgeting subsystem to assume the index is already committed,
779 * even though it is not.
780 */
781 ubifs_assert(c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c));
782 c->bi.old_idx_sz = c->calc_idx_sz;
783 c->bi.uncommitted_idx = 0;
784 c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
785 spin_unlock(&c->space_lock);
786 mutex_unlock(&c->tnc_mutex);
787
788 dbg_cmt("number of index LEBs %d", c->lst.idx_lebs);
789 dbg_cmt("size of index %llu", c->calc_idx_sz);
790 return err;
791
792out_free:
793 free_idx_lebs(c);
794out:
795 mutex_unlock(&c->tnc_mutex);
796 return err;
797}
798
799/**
800 * write_index - write index nodes.
801 * @c: UBIFS file-system description object
802 *
803 * This function writes the index nodes whose positions were laid out in the
804 * layout_in_empty_space function.
805 */
806static int write_index(struct ubifs_info *c)
807{
808 struct ubifs_idx_node *idx;
809 struct ubifs_znode *znode, *cnext;
810 int i, lnum, offs, len, next_len, buf_len, buf_offs, used;
811 int avail, wlen, err, lnum_pos = 0, blen, nxt_offs;
812
813 cnext = c->enext;
814 if (!cnext)
815 return 0;
816
817 /*
818 * Always write index nodes to the index head so that index nodes and
819 * other types of nodes are never mixed in the same erase block.
820 */
821 lnum = c->ihead_lnum;
822 buf_offs = c->ihead_offs;
823
824 /* Allocate commit buffer */
825 buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size);
826 used = 0;
827 avail = buf_len;
828
829 /* Ensure there is enough room for first write */
830 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
831 if (buf_offs + next_len > c->leb_size) {
832 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0,
833 LPROPS_TAKEN);
834 if (err)
835 return err;
836 lnum = -1;
837 }
838
839 while (1) {
840 cond_resched();
841
842 znode = cnext;
843 idx = c->cbuf + used;
844
845 /* Make index node */
846 idx->ch.node_type = UBIFS_IDX_NODE;
847 idx->child_cnt = cpu_to_le16(znode->child_cnt);
848 idx->level = cpu_to_le16(znode->level);
849 for (i = 0; i < znode->child_cnt; i++) {
850 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
851 struct ubifs_zbranch *zbr = &znode->zbranch[i];
852
853 key_write_idx(c, &zbr->key, &br->key);
854 br->lnum = cpu_to_le32(zbr->lnum);
855 br->offs = cpu_to_le32(zbr->offs);
856 br->len = cpu_to_le32(zbr->len);
857 if (!zbr->lnum || !zbr->len) {
858 ubifs_err(c, "bad ref in znode");
859 ubifs_dump_znode(c, znode);
860 if (zbr->znode)
861 ubifs_dump_znode(c, zbr->znode);
862 }
863 }
864 len = ubifs_idx_node_sz(c, znode->child_cnt);
865 ubifs_prepare_node(c, idx, len, 0);
866
867 /* Determine the index node position */
868 if (lnum == -1) {
869 lnum = c->ilebs[lnum_pos++];
870 buf_offs = 0;
871 used = 0;
872 avail = buf_len;
873 }
874 offs = buf_offs + used;
875
876 if (lnum != znode->lnum || offs != znode->offs ||
877 len != znode->len) {
878 ubifs_err(c, "inconsistent znode posn");
879 return -EINVAL;
880 }
881
882 /* Grab some stuff from znode while we still can */
883 cnext = znode->cnext;
884
885 ubifs_assert(ubifs_zn_dirty(znode));
886 ubifs_assert(ubifs_zn_cow(znode));
887
888 /*
889 * It is important that other threads should see %DIRTY_ZNODE
890 * flag cleared before %COW_ZNODE. Specifically, it matters in
891 * the 'dirty_cow_znode()' function. This is the reason for the
892 * first barrier. Also, we want the bit changes to be seen to
893 * other threads ASAP, to avoid unnecesarry copying, which is
894 * the reason for the second barrier.
895 */
896 clear_bit(DIRTY_ZNODE, &znode->flags);
897 smp_mb__before_atomic();
898 clear_bit(COW_ZNODE, &znode->flags);
899 smp_mb__after_atomic();
900
901 /*
902 * We have marked the znode as clean but have not updated the
903 * @c->clean_zn_cnt counter. If this znode becomes dirty again
904 * before 'free_obsolete_znodes()' is called, then
905 * @c->clean_zn_cnt will be decremented before it gets
906 * incremented (resulting in 2 decrements for the same znode).
907 * This means that @c->clean_zn_cnt may become negative for a
908 * while.
909 *
910 * Q: why we cannot increment @c->clean_zn_cnt?
911 * A: because we do not have the @c->tnc_mutex locked, and the
912 * following code would be racy and buggy:
913 *
914 * if (!ubifs_zn_obsolete(znode)) {
915 * atomic_long_inc(&c->clean_zn_cnt);
916 * atomic_long_inc(&ubifs_clean_zn_cnt);
917 * }
918 *
919 * Thus, we just delay the @c->clean_zn_cnt update until we
920 * have the mutex locked.
921 */
922
923 /* Do not access znode from this point on */
924
925 /* Update buffer positions */
926 wlen = used + len;
927 used += ALIGN(len, 8);
928 avail -= ALIGN(len, 8);
929
930 /*
931 * Calculate the next index node length to see if there is
932 * enough room for it
933 */
934 if (cnext == c->cnext)
935 next_len = 0;
936 else
937 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
938
939 nxt_offs = buf_offs + used + next_len;
940 if (next_len && nxt_offs <= c->leb_size) {
941 if (avail > 0)
942 continue;
943 else
944 blen = buf_len;
945 } else {
946 wlen = ALIGN(wlen, 8);
947 blen = ALIGN(wlen, c->min_io_size);
948 ubifs_pad(c, c->cbuf + wlen, blen - wlen);
949 }
950
951 /* The buffer is full or there are no more znodes to do */
952 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, blen);
953 if (err)
954 return err;
955 buf_offs += blen;
956 if (next_len) {
957 if (nxt_offs > c->leb_size) {
958 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0,
959 0, LPROPS_TAKEN);
960 if (err)
961 return err;
962 lnum = -1;
963 }
964 used -= blen;
965 if (used < 0)
966 used = 0;
967 avail = buf_len - used;
968 memmove(c->cbuf, c->cbuf + blen, used);
969 continue;
970 }
971 break;
972 }
973
974 if (lnum != c->dbg->new_ihead_lnum ||
975 buf_offs != c->dbg->new_ihead_offs) {
976 ubifs_err(c, "inconsistent ihead");
977 return -EINVAL;
978 }
979
980 c->ihead_lnum = lnum;
981 c->ihead_offs = buf_offs;
982
983 return 0;
984}
985
986/**
987 * free_obsolete_znodes - free obsolete znodes.
988 * @c: UBIFS file-system description object
989 *
990 * At the end of commit end, obsolete znodes are freed.
991 */
992static void free_obsolete_znodes(struct ubifs_info *c)
993{
994 struct ubifs_znode *znode, *cnext;
995
996 cnext = c->cnext;
997 do {
998 znode = cnext;
999 cnext = znode->cnext;
1000 if (ubifs_zn_obsolete(znode))
1001 kfree(znode);
1002 else {
1003 znode->cnext = NULL;
1004 atomic_long_inc(&c->clean_zn_cnt);
1005 atomic_long_inc(&ubifs_clean_zn_cnt);
1006 }
1007 } while (cnext != c->cnext);
1008}
1009
1010/**
1011 * return_gap_lebs - return LEBs used by the in-gap commit method.
1012 * @c: UBIFS file-system description object
1013 *
1014 * This function clears the "taken" flag for the LEBs which were used by the
1015 * "commit in-the-gaps" method.
1016 */
1017static int return_gap_lebs(struct ubifs_info *c)
1018{
1019 int *p, err;
1020
1021 if (!c->gap_lebs)
1022 return 0;
1023
1024 dbg_cmt("");
1025 for (p = c->gap_lebs; *p != -1; p++) {
1026 err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0,
1027 LPROPS_TAKEN, 0);
1028 if (err)
1029 return err;
1030 }
1031
1032 kfree(c->gap_lebs);
1033 c->gap_lebs = NULL;
1034 return 0;
1035}
1036
1037/**
1038 * ubifs_tnc_end_commit - update the TNC for commit end.
1039 * @c: UBIFS file-system description object
1040 *
1041 * Write the dirty znodes.
1042 */
1043int ubifs_tnc_end_commit(struct ubifs_info *c)
1044{
1045 int err;
1046
1047 if (!c->cnext)
1048 return 0;
1049
1050 err = return_gap_lebs(c);
1051 if (err)
1052 return err;
1053
1054 err = write_index(c);
1055 if (err)
1056 return err;
1057
1058 mutex_lock(&c->tnc_mutex);
1059
1060 dbg_cmt("TNC height is %d", c->zroot.znode->level + 1);
1061
1062 free_obsolete_znodes(c);
1063
1064 c->cnext = NULL;
1065 kfree(c->ilebs);
1066 c->ilebs = NULL;
1067
1068 mutex_unlock(&c->tnc_mutex);
1069
1070 return 0;
1071}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * This file is part of UBIFS.
4 *
5 * Copyright (C) 2006-2008 Nokia Corporation.
6 *
7 * Authors: Adrian Hunter
8 * Artem Bityutskiy (Битюцкий Артём)
9 */
10
11/* This file implements TNC functions for committing */
12
13#include <linux/random.h>
14#include "ubifs.h"
15
16/**
17 * make_idx_node - make an index node for fill-the-gaps method of TNC commit.
18 * @c: UBIFS file-system description object
19 * @idx: buffer in which to place new index node
20 * @znode: znode from which to make new index node
21 * @lnum: LEB number where new index node will be written
22 * @offs: offset where new index node will be written
23 * @len: length of new index node
24 */
25static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx,
26 struct ubifs_znode *znode, int lnum, int offs, int len)
27{
28 struct ubifs_znode *zp;
29 u8 hash[UBIFS_HASH_ARR_SZ];
30 int i, err;
31
32 /* Make index node */
33 idx->ch.node_type = UBIFS_IDX_NODE;
34 idx->child_cnt = cpu_to_le16(znode->child_cnt);
35 idx->level = cpu_to_le16(znode->level);
36 for (i = 0; i < znode->child_cnt; i++) {
37 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
38 struct ubifs_zbranch *zbr = &znode->zbranch[i];
39
40 key_write_idx(c, &zbr->key, &br->key);
41 br->lnum = cpu_to_le32(zbr->lnum);
42 br->offs = cpu_to_le32(zbr->offs);
43 br->len = cpu_to_le32(zbr->len);
44 ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br));
45 if (!zbr->lnum || !zbr->len) {
46 ubifs_err(c, "bad ref in znode");
47 ubifs_dump_znode(c, znode);
48 if (zbr->znode)
49 ubifs_dump_znode(c, zbr->znode);
50
51 return -EINVAL;
52 }
53 }
54 ubifs_prepare_node(c, idx, len, 0);
55 ubifs_node_calc_hash(c, idx, hash);
56
57 znode->lnum = lnum;
58 znode->offs = offs;
59 znode->len = len;
60
61 err = insert_old_idx_znode(c, znode);
62
63 /* Update the parent */
64 zp = znode->parent;
65 if (zp) {
66 struct ubifs_zbranch *zbr;
67
68 zbr = &zp->zbranch[znode->iip];
69 zbr->lnum = lnum;
70 zbr->offs = offs;
71 zbr->len = len;
72 ubifs_copy_hash(c, hash, zbr->hash);
73 } else {
74 c->zroot.lnum = lnum;
75 c->zroot.offs = offs;
76 c->zroot.len = len;
77 ubifs_copy_hash(c, hash, c->zroot.hash);
78 }
79 c->calc_idx_sz += ALIGN(len, 8);
80
81 atomic_long_dec(&c->dirty_zn_cnt);
82
83 ubifs_assert(c, ubifs_zn_dirty(znode));
84 ubifs_assert(c, ubifs_zn_cow(znode));
85
86 /*
87 * Note, unlike 'write_index()' we do not add memory barriers here
88 * because this function is called with @c->tnc_mutex locked.
89 */
90 __clear_bit(DIRTY_ZNODE, &znode->flags);
91 __clear_bit(COW_ZNODE, &znode->flags);
92
93 return err;
94}
95
96/**
97 * fill_gap - make index nodes in gaps in dirty index LEBs.
98 * @c: UBIFS file-system description object
99 * @lnum: LEB number that gap appears in
100 * @gap_start: offset of start of gap
101 * @gap_end: offset of end of gap
102 * @dirt: adds dirty space to this
103 *
104 * This function returns the number of index nodes written into the gap.
105 */
106static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end,
107 int *dirt)
108{
109 int len, gap_remains, gap_pos, written, pad_len;
110
111 ubifs_assert(c, (gap_start & 7) == 0);
112 ubifs_assert(c, (gap_end & 7) == 0);
113 ubifs_assert(c, gap_end >= gap_start);
114
115 gap_remains = gap_end - gap_start;
116 if (!gap_remains)
117 return 0;
118 gap_pos = gap_start;
119 written = 0;
120 while (c->enext) {
121 len = ubifs_idx_node_sz(c, c->enext->child_cnt);
122 if (len < gap_remains) {
123 struct ubifs_znode *znode = c->enext;
124 const int alen = ALIGN(len, 8);
125 int err;
126
127 ubifs_assert(c, alen <= gap_remains);
128 err = make_idx_node(c, c->ileb_buf + gap_pos, znode,
129 lnum, gap_pos, len);
130 if (err)
131 return err;
132 gap_remains -= alen;
133 gap_pos += alen;
134 c->enext = znode->cnext;
135 if (c->enext == c->cnext)
136 c->enext = NULL;
137 written += 1;
138 } else
139 break;
140 }
141 if (gap_end == c->leb_size) {
142 c->ileb_len = ALIGN(gap_pos, c->min_io_size);
143 /* Pad to end of min_io_size */
144 pad_len = c->ileb_len - gap_pos;
145 } else
146 /* Pad to end of gap */
147 pad_len = gap_remains;
148 dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d",
149 lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len);
150 ubifs_pad(c, c->ileb_buf + gap_pos, pad_len);
151 *dirt += pad_len;
152 return written;
153}
154
155/**
156 * find_old_idx - find an index node obsoleted since the last commit start.
157 * @c: UBIFS file-system description object
158 * @lnum: LEB number of obsoleted index node
159 * @offs: offset of obsoleted index node
160 *
161 * Returns %1 if found and %0 otherwise.
162 */
163static int find_old_idx(struct ubifs_info *c, int lnum, int offs)
164{
165 struct ubifs_old_idx *o;
166 struct rb_node *p;
167
168 p = c->old_idx.rb_node;
169 while (p) {
170 o = rb_entry(p, struct ubifs_old_idx, rb);
171 if (lnum < o->lnum)
172 p = p->rb_left;
173 else if (lnum > o->lnum)
174 p = p->rb_right;
175 else if (offs < o->offs)
176 p = p->rb_left;
177 else if (offs > o->offs)
178 p = p->rb_right;
179 else
180 return 1;
181 }
182 return 0;
183}
184
185/**
186 * is_idx_node_in_use - determine if an index node can be overwritten.
187 * @c: UBIFS file-system description object
188 * @key: key of index node
189 * @level: index node level
190 * @lnum: LEB number of index node
191 * @offs: offset of index node
192 *
193 * If @key / @lnum / @offs identify an index node that was not part of the old
194 * index, then this function returns %0 (obsolete). Else if the index node was
195 * part of the old index but is now dirty %1 is returned, else if it is clean %2
196 * is returned. A negative error code is returned on failure.
197 */
198static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
199 int level, int lnum, int offs)
200{
201 int ret;
202
203 ret = is_idx_node_in_tnc(c, key, level, lnum, offs);
204 if (ret < 0)
205 return ret; /* Error code */
206 if (ret == 0)
207 if (find_old_idx(c, lnum, offs))
208 return 1;
209 return ret;
210}
211
212/**
213 * layout_leb_in_gaps - layout index nodes using in-the-gaps method.
214 * @c: UBIFS file-system description object
215 * @p: return LEB number in @c->gap_lebs[p]
216 *
217 * This function lays out new index nodes for dirty znodes using in-the-gaps
218 * method of TNC commit.
219 * This function merely puts the next znode into the next gap, making no attempt
220 * to try to maximise the number of znodes that fit.
221 * This function returns the number of index nodes written into the gaps, or a
222 * negative error code on failure.
223 */
224static int layout_leb_in_gaps(struct ubifs_info *c, int p)
225{
226 struct ubifs_scan_leb *sleb;
227 struct ubifs_scan_node *snod;
228 int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written;
229
230 tot_written = 0;
231 /* Get an index LEB with lots of obsolete index nodes */
232 lnum = ubifs_find_dirty_idx_leb(c);
233 if (lnum < 0)
234 /*
235 * There also may be dirt in the index head that could be
236 * filled, however we do not check there at present.
237 */
238 return lnum; /* Error code */
239 c->gap_lebs[p] = lnum;
240 dbg_gc("LEB %d", lnum);
241 /*
242 * Scan the index LEB. We use the generic scan for this even though
243 * it is more comprehensive and less efficient than is needed for this
244 * purpose.
245 */
246 sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0);
247 c->ileb_len = 0;
248 if (IS_ERR(sleb))
249 return PTR_ERR(sleb);
250 gap_start = 0;
251 list_for_each_entry(snod, &sleb->nodes, list) {
252 struct ubifs_idx_node *idx;
253 int in_use, level;
254
255 ubifs_assert(c, snod->type == UBIFS_IDX_NODE);
256 idx = snod->node;
257 key_read(c, ubifs_idx_key(c, idx), &snod->key);
258 level = le16_to_cpu(idx->level);
259 /* Determine if the index node is in use (not obsolete) */
260 in_use = is_idx_node_in_use(c, &snod->key, level, lnum,
261 snod->offs);
262 if (in_use < 0) {
263 ubifs_scan_destroy(sleb);
264 return in_use; /* Error code */
265 }
266 if (in_use) {
267 if (in_use == 1)
268 dirt += ALIGN(snod->len, 8);
269 /*
270 * The obsolete index nodes form gaps that can be
271 * overwritten. This gap has ended because we have
272 * found an index node that is still in use
273 * i.e. not obsolete
274 */
275 gap_end = snod->offs;
276 /* Try to fill gap */
277 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
278 if (written < 0) {
279 ubifs_scan_destroy(sleb);
280 return written; /* Error code */
281 }
282 tot_written += written;
283 gap_start = ALIGN(snod->offs + snod->len, 8);
284 }
285 }
286 ubifs_scan_destroy(sleb);
287 c->ileb_len = c->leb_size;
288 gap_end = c->leb_size;
289 /* Try to fill gap */
290 written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
291 if (written < 0)
292 return written; /* Error code */
293 tot_written += written;
294 if (tot_written == 0) {
295 struct ubifs_lprops lp;
296
297 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
298 err = ubifs_read_one_lp(c, lnum, &lp);
299 if (err)
300 return err;
301 if (lp.free == c->leb_size) {
302 /*
303 * We must have snatched this LEB from the idx_gc list
304 * so we need to correct the free and dirty space.
305 */
306 err = ubifs_change_one_lp(c, lnum,
307 c->leb_size - c->ileb_len,
308 dirt, 0, 0, 0);
309 if (err)
310 return err;
311 }
312 return 0;
313 }
314 err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt,
315 0, 0, 0);
316 if (err)
317 return err;
318 err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len);
319 if (err)
320 return err;
321 dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
322 return tot_written;
323}
324
325/**
326 * get_leb_cnt - calculate the number of empty LEBs needed to commit.
327 * @c: UBIFS file-system description object
328 * @cnt: number of znodes to commit
329 *
330 * This function returns the number of empty LEBs needed to commit @cnt znodes
331 * to the current index head. The number is not exact and may be more than
332 * needed.
333 */
334static int get_leb_cnt(struct ubifs_info *c, int cnt)
335{
336 int d;
337
338 /* Assume maximum index node size (i.e. overestimate space needed) */
339 cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz;
340 if (cnt < 0)
341 cnt = 0;
342 d = c->leb_size / c->max_idx_node_sz;
343 return DIV_ROUND_UP(cnt, d);
344}
345
346/**
347 * layout_in_gaps - in-the-gaps method of committing TNC.
348 * @c: UBIFS file-system description object
349 * @cnt: number of dirty znodes to commit.
350 *
351 * This function lays out new index nodes for dirty znodes using in-the-gaps
352 * method of TNC commit.
353 *
354 * This function returns %0 on success and a negative error code on failure.
355 */
356static int layout_in_gaps(struct ubifs_info *c, int cnt)
357{
358 int err, leb_needed_cnt, written, p = 0, old_idx_lebs, *gap_lebs;
359
360 dbg_gc("%d znodes to write", cnt);
361
362 c->gap_lebs = kmalloc_array(c->lst.idx_lebs + 1, sizeof(int),
363 GFP_NOFS);
364 if (!c->gap_lebs)
365 return -ENOMEM;
366
367 old_idx_lebs = c->lst.idx_lebs;
368 do {
369 ubifs_assert(c, p < c->lst.idx_lebs);
370 written = layout_leb_in_gaps(c, p);
371 if (written < 0) {
372 err = written;
373 if (err != -ENOSPC) {
374 kfree(c->gap_lebs);
375 c->gap_lebs = NULL;
376 return err;
377 }
378 if (!dbg_is_chk_index(c)) {
379 /*
380 * Do not print scary warnings if the debugging
381 * option which forces in-the-gaps is enabled.
382 */
383 ubifs_warn(c, "out of space");
384 ubifs_dump_budg(c, &c->bi);
385 ubifs_dump_lprops(c);
386 }
387 /* Try to commit anyway */
388 break;
389 }
390 p++;
391 cnt -= written;
392 leb_needed_cnt = get_leb_cnt(c, cnt);
393 dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
394 leb_needed_cnt, c->ileb_cnt);
395 /*
396 * Dynamically change the size of @c->gap_lebs to prevent
397 * oob, because @c->lst.idx_lebs could be increased by
398 * function @get_idx_gc_leb (called by layout_leb_in_gaps->
399 * ubifs_find_dirty_idx_leb) during loop. Only enlarge
400 * @c->gap_lebs when needed.
401 *
402 */
403 if (leb_needed_cnt > c->ileb_cnt && p >= old_idx_lebs &&
404 old_idx_lebs < c->lst.idx_lebs) {
405 old_idx_lebs = c->lst.idx_lebs;
406 gap_lebs = krealloc(c->gap_lebs, sizeof(int) *
407 (old_idx_lebs + 1), GFP_NOFS);
408 if (!gap_lebs) {
409 kfree(c->gap_lebs);
410 c->gap_lebs = NULL;
411 return -ENOMEM;
412 }
413 c->gap_lebs = gap_lebs;
414 }
415 } while (leb_needed_cnt > c->ileb_cnt);
416
417 c->gap_lebs[p] = -1;
418 return 0;
419}
420
421/**
422 * layout_in_empty_space - layout index nodes in empty space.
423 * @c: UBIFS file-system description object
424 *
425 * This function lays out new index nodes for dirty znodes using empty LEBs.
426 *
427 * This function returns %0 on success and a negative error code on failure.
428 */
429static int layout_in_empty_space(struct ubifs_info *c)
430{
431 struct ubifs_znode *znode, *cnext, *zp;
432 int lnum, offs, len, next_len, buf_len, buf_offs, used, avail;
433 int wlen, blen, err;
434
435 cnext = c->enext;
436 if (!cnext)
437 return 0;
438
439 lnum = c->ihead_lnum;
440 buf_offs = c->ihead_offs;
441
442 buf_len = ubifs_idx_node_sz(c, c->fanout);
443 buf_len = ALIGN(buf_len, c->min_io_size);
444 used = 0;
445 avail = buf_len;
446
447 /* Ensure there is enough room for first write */
448 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
449 if (buf_offs + next_len > c->leb_size)
450 lnum = -1;
451
452 while (1) {
453 znode = cnext;
454
455 len = ubifs_idx_node_sz(c, znode->child_cnt);
456
457 /* Determine the index node position */
458 if (lnum == -1) {
459 if (c->ileb_nxt >= c->ileb_cnt) {
460 ubifs_err(c, "out of space");
461 return -ENOSPC;
462 }
463 lnum = c->ilebs[c->ileb_nxt++];
464 buf_offs = 0;
465 used = 0;
466 avail = buf_len;
467 }
468
469 offs = buf_offs + used;
470
471 znode->lnum = lnum;
472 znode->offs = offs;
473 znode->len = len;
474
475 /* Update the parent */
476 zp = znode->parent;
477 if (zp) {
478 struct ubifs_zbranch *zbr;
479 int i;
480
481 i = znode->iip;
482 zbr = &zp->zbranch[i];
483 zbr->lnum = lnum;
484 zbr->offs = offs;
485 zbr->len = len;
486 } else {
487 c->zroot.lnum = lnum;
488 c->zroot.offs = offs;
489 c->zroot.len = len;
490 }
491 c->calc_idx_sz += ALIGN(len, 8);
492
493 /*
494 * Once lprops is updated, we can decrease the dirty znode count
495 * but it is easier to just do it here.
496 */
497 atomic_long_dec(&c->dirty_zn_cnt);
498
499 /*
500 * Calculate the next index node length to see if there is
501 * enough room for it
502 */
503 cnext = znode->cnext;
504 if (cnext == c->cnext)
505 next_len = 0;
506 else
507 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
508
509 /* Update buffer positions */
510 wlen = used + len;
511 used += ALIGN(len, 8);
512 avail -= ALIGN(len, 8);
513
514 if (next_len != 0 &&
515 buf_offs + used + next_len <= c->leb_size &&
516 avail > 0)
517 continue;
518
519 if (avail <= 0 && next_len &&
520 buf_offs + used + next_len <= c->leb_size)
521 blen = buf_len;
522 else
523 blen = ALIGN(wlen, c->min_io_size);
524
525 /* The buffer is full or there are no more znodes to do */
526 buf_offs += blen;
527 if (next_len) {
528 if (buf_offs + next_len > c->leb_size) {
529 err = ubifs_update_one_lp(c, lnum,
530 c->leb_size - buf_offs, blen - used,
531 0, 0);
532 if (err)
533 return err;
534 lnum = -1;
535 }
536 used -= blen;
537 if (used < 0)
538 used = 0;
539 avail = buf_len - used;
540 continue;
541 }
542 err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs,
543 blen - used, 0, 0);
544 if (err)
545 return err;
546 break;
547 }
548
549 c->dbg->new_ihead_lnum = lnum;
550 c->dbg->new_ihead_offs = buf_offs;
551
552 return 0;
553}
554
555/**
556 * layout_commit - determine positions of index nodes to commit.
557 * @c: UBIFS file-system description object
558 * @no_space: indicates that insufficient empty LEBs were allocated
559 * @cnt: number of znodes to commit
560 *
561 * Calculate and update the positions of index nodes to commit. If there were
562 * an insufficient number of empty LEBs allocated, then index nodes are placed
563 * into the gaps created by obsolete index nodes in non-empty index LEBs. For
564 * this purpose, an obsolete index node is one that was not in the index as at
565 * the end of the last commit. To write "in-the-gaps" requires that those index
566 * LEBs are updated atomically in-place.
567 */
568static int layout_commit(struct ubifs_info *c, int no_space, int cnt)
569{
570 int err;
571
572 if (no_space) {
573 err = layout_in_gaps(c, cnt);
574 if (err)
575 return err;
576 }
577 err = layout_in_empty_space(c);
578 return err;
579}
580
581/**
582 * find_first_dirty - find first dirty znode.
583 * @znode: znode to begin searching from
584 */
585static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode)
586{
587 int i, cont;
588
589 if (!znode)
590 return NULL;
591
592 while (1) {
593 if (znode->level == 0) {
594 if (ubifs_zn_dirty(znode))
595 return znode;
596 return NULL;
597 }
598 cont = 0;
599 for (i = 0; i < znode->child_cnt; i++) {
600 struct ubifs_zbranch *zbr = &znode->zbranch[i];
601
602 if (zbr->znode && ubifs_zn_dirty(zbr->znode)) {
603 znode = zbr->znode;
604 cont = 1;
605 break;
606 }
607 }
608 if (!cont) {
609 if (ubifs_zn_dirty(znode))
610 return znode;
611 return NULL;
612 }
613 }
614}
615
616/**
617 * find_next_dirty - find next dirty znode.
618 * @znode: znode to begin searching from
619 */
620static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode)
621{
622 int n = znode->iip + 1;
623
624 znode = znode->parent;
625 if (!znode)
626 return NULL;
627 for (; n < znode->child_cnt; n++) {
628 struct ubifs_zbranch *zbr = &znode->zbranch[n];
629
630 if (zbr->znode && ubifs_zn_dirty(zbr->znode))
631 return find_first_dirty(zbr->znode);
632 }
633 return znode;
634}
635
636/**
637 * get_znodes_to_commit - create list of dirty znodes to commit.
638 * @c: UBIFS file-system description object
639 *
640 * This function returns the number of znodes to commit.
641 */
642static int get_znodes_to_commit(struct ubifs_info *c)
643{
644 struct ubifs_znode *znode, *cnext;
645 int cnt = 0;
646
647 c->cnext = find_first_dirty(c->zroot.znode);
648 znode = c->enext = c->cnext;
649 if (!znode) {
650 dbg_cmt("no znodes to commit");
651 return 0;
652 }
653 cnt += 1;
654 while (1) {
655 ubifs_assert(c, !ubifs_zn_cow(znode));
656 __set_bit(COW_ZNODE, &znode->flags);
657 znode->alt = 0;
658 cnext = find_next_dirty(znode);
659 if (!cnext) {
660 ubifs_assert(c, !znode->parent);
661 znode->cparent = NULL;
662 znode->cnext = c->cnext;
663 break;
664 }
665 znode->cparent = znode->parent;
666 znode->ciip = znode->iip;
667 znode->cnext = cnext;
668 znode = cnext;
669 cnt += 1;
670 }
671 dbg_cmt("committing %d znodes", cnt);
672 ubifs_assert(c, cnt == atomic_long_read(&c->dirty_zn_cnt));
673 return cnt;
674}
675
676/**
677 * alloc_idx_lebs - allocate empty LEBs to be used to commit.
678 * @c: UBIFS file-system description object
679 * @cnt: number of znodes to commit
680 *
681 * This function returns %-ENOSPC if it cannot allocate a sufficient number of
682 * empty LEBs. %0 is returned on success, otherwise a negative error code
683 * is returned.
684 */
685static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
686{
687 int i, leb_cnt, lnum;
688
689 c->ileb_cnt = 0;
690 c->ileb_nxt = 0;
691 leb_cnt = get_leb_cnt(c, cnt);
692 dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt);
693 if (!leb_cnt)
694 return 0;
695 c->ilebs = kmalloc_array(leb_cnt, sizeof(int), GFP_NOFS);
696 if (!c->ilebs)
697 return -ENOMEM;
698 for (i = 0; i < leb_cnt; i++) {
699 lnum = ubifs_find_free_leb_for_idx(c);
700 if (lnum < 0)
701 return lnum;
702 c->ilebs[c->ileb_cnt++] = lnum;
703 dbg_cmt("LEB %d", lnum);
704 }
705 if (dbg_is_chk_index(c) && !get_random_u32_below(8))
706 return -ENOSPC;
707 return 0;
708}
709
710/**
711 * free_unused_idx_lebs - free unused LEBs that were allocated for the commit.
712 * @c: UBIFS file-system description object
713 *
714 * It is possible that we allocate more empty LEBs for the commit than we need.
715 * This functions frees the surplus.
716 *
717 * This function returns %0 on success and a negative error code on failure.
718 */
719static int free_unused_idx_lebs(struct ubifs_info *c)
720{
721 int i, err = 0, lnum, er;
722
723 for (i = c->ileb_nxt; i < c->ileb_cnt; i++) {
724 lnum = c->ilebs[i];
725 dbg_cmt("LEB %d", lnum);
726 er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
727 LPROPS_INDEX | LPROPS_TAKEN, 0);
728 if (!err)
729 err = er;
730 }
731 return err;
732}
733
734/**
735 * free_idx_lebs - free unused LEBs after commit end.
736 * @c: UBIFS file-system description object
737 *
738 * This function returns %0 on success and a negative error code on failure.
739 */
740static int free_idx_lebs(struct ubifs_info *c)
741{
742 int err;
743
744 err = free_unused_idx_lebs(c);
745 kfree(c->ilebs);
746 c->ilebs = NULL;
747 return err;
748}
749
750/**
751 * ubifs_tnc_start_commit - start TNC commit.
752 * @c: UBIFS file-system description object
753 * @zroot: new index root position is returned here
754 *
755 * This function prepares the list of indexing nodes to commit and lays out
756 * their positions on flash. If there is not enough free space it uses the
757 * in-gap commit method. Returns zero in case of success and a negative error
758 * code in case of failure.
759 */
760int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot)
761{
762 int err = 0, cnt;
763
764 mutex_lock(&c->tnc_mutex);
765 err = dbg_check_tnc(c, 1);
766 if (err)
767 goto out;
768 cnt = get_znodes_to_commit(c);
769 if (cnt != 0) {
770 int no_space = 0;
771
772 err = alloc_idx_lebs(c, cnt);
773 if (err == -ENOSPC)
774 no_space = 1;
775 else if (err)
776 goto out_free;
777 err = layout_commit(c, no_space, cnt);
778 if (err)
779 goto out_free;
780 ubifs_assert(c, atomic_long_read(&c->dirty_zn_cnt) == 0);
781 err = free_unused_idx_lebs(c);
782 if (err)
783 goto out;
784 }
785 destroy_old_idx(c);
786 memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch));
787
788 err = ubifs_save_dirty_idx_lnums(c);
789 if (err)
790 goto out;
791
792 spin_lock(&c->space_lock);
793 /*
794 * Although we have not finished committing yet, update size of the
795 * committed index ('c->bi.old_idx_sz') and zero out the index growth
796 * budget. It is OK to do this now, because we've reserved all the
797 * space which is needed to commit the index, and it is save for the
798 * budgeting subsystem to assume the index is already committed,
799 * even though it is not.
800 */
801 ubifs_assert(c, c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c));
802 c->bi.old_idx_sz = c->calc_idx_sz;
803 c->bi.uncommitted_idx = 0;
804 c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
805 spin_unlock(&c->space_lock);
806 mutex_unlock(&c->tnc_mutex);
807
808 dbg_cmt("number of index LEBs %d", c->lst.idx_lebs);
809 dbg_cmt("size of index %llu", c->calc_idx_sz);
810 return err;
811
812out_free:
813 free_idx_lebs(c);
814out:
815 mutex_unlock(&c->tnc_mutex);
816 return err;
817}
818
819/**
820 * write_index - write index nodes.
821 * @c: UBIFS file-system description object
822 *
823 * This function writes the index nodes whose positions were laid out in the
824 * layout_in_empty_space function.
825 */
826static int write_index(struct ubifs_info *c)
827{
828 struct ubifs_idx_node *idx;
829 struct ubifs_znode *znode, *cnext;
830 int i, lnum, offs, len, next_len, buf_len, buf_offs, used;
831 int avail, wlen, err, lnum_pos = 0, blen, nxt_offs;
832
833 cnext = c->enext;
834 if (!cnext)
835 return 0;
836
837 /*
838 * Always write index nodes to the index head so that index nodes and
839 * other types of nodes are never mixed in the same erase block.
840 */
841 lnum = c->ihead_lnum;
842 buf_offs = c->ihead_offs;
843
844 /* Allocate commit buffer */
845 buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size);
846 used = 0;
847 avail = buf_len;
848
849 /* Ensure there is enough room for first write */
850 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
851 if (buf_offs + next_len > c->leb_size) {
852 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0,
853 LPROPS_TAKEN);
854 if (err)
855 return err;
856 lnum = -1;
857 }
858
859 while (1) {
860 u8 hash[UBIFS_HASH_ARR_SZ];
861
862 cond_resched();
863
864 znode = cnext;
865 idx = c->cbuf + used;
866
867 /* Make index node */
868 idx->ch.node_type = UBIFS_IDX_NODE;
869 idx->child_cnt = cpu_to_le16(znode->child_cnt);
870 idx->level = cpu_to_le16(znode->level);
871 for (i = 0; i < znode->child_cnt; i++) {
872 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
873 struct ubifs_zbranch *zbr = &znode->zbranch[i];
874
875 key_write_idx(c, &zbr->key, &br->key);
876 br->lnum = cpu_to_le32(zbr->lnum);
877 br->offs = cpu_to_le32(zbr->offs);
878 br->len = cpu_to_le32(zbr->len);
879 ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br));
880 if (!zbr->lnum || !zbr->len) {
881 ubifs_err(c, "bad ref in znode");
882 ubifs_dump_znode(c, znode);
883 if (zbr->znode)
884 ubifs_dump_znode(c, zbr->znode);
885
886 return -EINVAL;
887 }
888 }
889 len = ubifs_idx_node_sz(c, znode->child_cnt);
890 ubifs_prepare_node(c, idx, len, 0);
891 ubifs_node_calc_hash(c, idx, hash);
892
893 mutex_lock(&c->tnc_mutex);
894
895 if (znode->cparent)
896 ubifs_copy_hash(c, hash,
897 znode->cparent->zbranch[znode->ciip].hash);
898
899 if (znode->parent) {
900 if (!ubifs_zn_obsolete(znode))
901 ubifs_copy_hash(c, hash,
902 znode->parent->zbranch[znode->iip].hash);
903 } else {
904 ubifs_copy_hash(c, hash, c->zroot.hash);
905 }
906
907 mutex_unlock(&c->tnc_mutex);
908
909 /* Determine the index node position */
910 if (lnum == -1) {
911 lnum = c->ilebs[lnum_pos++];
912 buf_offs = 0;
913 used = 0;
914 avail = buf_len;
915 }
916 offs = buf_offs + used;
917
918 if (lnum != znode->lnum || offs != znode->offs ||
919 len != znode->len) {
920 ubifs_err(c, "inconsistent znode posn");
921 return -EINVAL;
922 }
923
924 /* Grab some stuff from znode while we still can */
925 cnext = znode->cnext;
926
927 ubifs_assert(c, ubifs_zn_dirty(znode));
928 ubifs_assert(c, ubifs_zn_cow(znode));
929
930 /*
931 * It is important that other threads should see %DIRTY_ZNODE
932 * flag cleared before %COW_ZNODE. Specifically, it matters in
933 * the 'dirty_cow_znode()' function. This is the reason for the
934 * first barrier. Also, we want the bit changes to be seen to
935 * other threads ASAP, to avoid unnecessary copying, which is
936 * the reason for the second barrier.
937 */
938 clear_bit(DIRTY_ZNODE, &znode->flags);
939 smp_mb__before_atomic();
940 clear_bit(COW_ZNODE, &znode->flags);
941 smp_mb__after_atomic();
942
943 /*
944 * We have marked the znode as clean but have not updated the
945 * @c->clean_zn_cnt counter. If this znode becomes dirty again
946 * before 'free_obsolete_znodes()' is called, then
947 * @c->clean_zn_cnt will be decremented before it gets
948 * incremented (resulting in 2 decrements for the same znode).
949 * This means that @c->clean_zn_cnt may become negative for a
950 * while.
951 *
952 * Q: why we cannot increment @c->clean_zn_cnt?
953 * A: because we do not have the @c->tnc_mutex locked, and the
954 * following code would be racy and buggy:
955 *
956 * if (!ubifs_zn_obsolete(znode)) {
957 * atomic_long_inc(&c->clean_zn_cnt);
958 * atomic_long_inc(&ubifs_clean_zn_cnt);
959 * }
960 *
961 * Thus, we just delay the @c->clean_zn_cnt update until we
962 * have the mutex locked.
963 */
964
965 /* Do not access znode from this point on */
966
967 /* Update buffer positions */
968 wlen = used + len;
969 used += ALIGN(len, 8);
970 avail -= ALIGN(len, 8);
971
972 /*
973 * Calculate the next index node length to see if there is
974 * enough room for it
975 */
976 if (cnext == c->cnext)
977 next_len = 0;
978 else
979 next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
980
981 nxt_offs = buf_offs + used + next_len;
982 if (next_len && nxt_offs <= c->leb_size) {
983 if (avail > 0)
984 continue;
985 else
986 blen = buf_len;
987 } else {
988 wlen = ALIGN(wlen, 8);
989 blen = ALIGN(wlen, c->min_io_size);
990 ubifs_pad(c, c->cbuf + wlen, blen - wlen);
991 }
992
993 /* The buffer is full or there are no more znodes to do */
994 err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, blen);
995 if (err)
996 return err;
997 buf_offs += blen;
998 if (next_len) {
999 if (nxt_offs > c->leb_size) {
1000 err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0,
1001 0, LPROPS_TAKEN);
1002 if (err)
1003 return err;
1004 lnum = -1;
1005 }
1006 used -= blen;
1007 if (used < 0)
1008 used = 0;
1009 avail = buf_len - used;
1010 memmove(c->cbuf, c->cbuf + blen, used);
1011 continue;
1012 }
1013 break;
1014 }
1015
1016 if (lnum != c->dbg->new_ihead_lnum ||
1017 buf_offs != c->dbg->new_ihead_offs) {
1018 ubifs_err(c, "inconsistent ihead");
1019 return -EINVAL;
1020 }
1021
1022 c->ihead_lnum = lnum;
1023 c->ihead_offs = buf_offs;
1024
1025 return 0;
1026}
1027
1028/**
1029 * free_obsolete_znodes - free obsolete znodes.
1030 * @c: UBIFS file-system description object
1031 *
1032 * At the end of commit end, obsolete znodes are freed.
1033 */
1034static void free_obsolete_znodes(struct ubifs_info *c)
1035{
1036 struct ubifs_znode *znode, *cnext;
1037
1038 cnext = c->cnext;
1039 do {
1040 znode = cnext;
1041 cnext = znode->cnext;
1042 if (ubifs_zn_obsolete(znode))
1043 kfree(znode);
1044 else {
1045 znode->cnext = NULL;
1046 atomic_long_inc(&c->clean_zn_cnt);
1047 atomic_long_inc(&ubifs_clean_zn_cnt);
1048 }
1049 } while (cnext != c->cnext);
1050}
1051
1052/**
1053 * return_gap_lebs - return LEBs used by the in-gap commit method.
1054 * @c: UBIFS file-system description object
1055 *
1056 * This function clears the "taken" flag for the LEBs which were used by the
1057 * "commit in-the-gaps" method.
1058 */
1059static int return_gap_lebs(struct ubifs_info *c)
1060{
1061 int *p, err;
1062
1063 if (!c->gap_lebs)
1064 return 0;
1065
1066 dbg_cmt("");
1067 for (p = c->gap_lebs; *p != -1; p++) {
1068 err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0,
1069 LPROPS_TAKEN, 0);
1070 if (err)
1071 return err;
1072 }
1073
1074 kfree(c->gap_lebs);
1075 c->gap_lebs = NULL;
1076 return 0;
1077}
1078
1079/**
1080 * ubifs_tnc_end_commit - update the TNC for commit end.
1081 * @c: UBIFS file-system description object
1082 *
1083 * Write the dirty znodes.
1084 */
1085int ubifs_tnc_end_commit(struct ubifs_info *c)
1086{
1087 int err;
1088
1089 if (!c->cnext)
1090 return 0;
1091
1092 err = return_gap_lebs(c);
1093 if (err)
1094 return err;
1095
1096 err = write_index(c);
1097 if (err)
1098 return err;
1099
1100 mutex_lock(&c->tnc_mutex);
1101
1102 dbg_cmt("TNC height is %d", c->zroot.znode->level + 1);
1103
1104 free_obsolete_znodes(c);
1105
1106 c->cnext = NULL;
1107 kfree(c->ilebs);
1108 c->ilebs = NULL;
1109
1110 mutex_unlock(&c->tnc_mutex);
1111
1112 return 0;
1113}