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1e51764a AB |
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 | ||
2b1844a8 | 25 | #include <linux/random.h> |
8d7819b4 | 26 | #include "ubifs.h" |
1e51764a AB |
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 | */ | |
37 | static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx, | |
38 | struct ubifs_znode *znode, int lnum, int offs, int len) | |
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("bad ref in znode"); | |
edf6be24 | 57 | ubifs_dump_znode(c, znode); |
1e51764a | 58 | if (zbr->znode) |
edf6be24 | 59 | ubifs_dump_znode(c, zbr->znode); |
1e51764a AB |
60 | } |
61 | } | |
62 | ubifs_prepare_node(c, idx, len, 0); | |
63 | ||
64 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
65 | znode->lnum = lnum; | |
66 | znode->offs = offs; | |
67 | znode->len = len; | |
68 | #endif | |
69 | ||
70 | err = insert_old_idx_znode(c, znode); | |
71 | ||
72 | /* Update the parent */ | |
73 | zp = znode->parent; | |
74 | if (zp) { | |
75 | struct ubifs_zbranch *zbr; | |
76 | ||
77 | zbr = &zp->zbranch[znode->iip]; | |
78 | zbr->lnum = lnum; | |
79 | zbr->offs = offs; | |
80 | zbr->len = len; | |
81 | } else { | |
82 | c->zroot.lnum = lnum; | |
83 | c->zroot.offs = offs; | |
84 | c->zroot.len = len; | |
85 | } | |
86 | c->calc_idx_sz += ALIGN(len, 8); | |
87 | ||
88 | atomic_long_dec(&c->dirty_zn_cnt); | |
89 | ||
90 | ubifs_assert(ubifs_zn_dirty(znode)); | |
f42eed7c | 91 | ubifs_assert(ubifs_zn_cow(znode)); |
1e51764a | 92 | |
06b282a4 AB |
93 | /* |
94 | * Note, unlike 'write_index()' we do not add memory barriers here | |
95 | * because this function is called with @c->tnc_mutex locked. | |
96 | */ | |
1e51764a AB |
97 | __clear_bit(DIRTY_ZNODE, &znode->flags); |
98 | __clear_bit(COW_ZNODE, &znode->flags); | |
99 | ||
100 | return err; | |
101 | } | |
102 | ||
103 | /** | |
104 | * fill_gap - make index nodes in gaps in dirty index LEBs. | |
105 | * @c: UBIFS file-system description object | |
106 | * @lnum: LEB number that gap appears in | |
107 | * @gap_start: offset of start of gap | |
108 | * @gap_end: offset of end of gap | |
109 | * @dirt: adds dirty space to this | |
110 | * | |
111 | * This function returns the number of index nodes written into the gap. | |
112 | */ | |
113 | static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end, | |
114 | int *dirt) | |
115 | { | |
116 | int len, gap_remains, gap_pos, written, pad_len; | |
117 | ||
118 | ubifs_assert((gap_start & 7) == 0); | |
119 | ubifs_assert((gap_end & 7) == 0); | |
120 | ubifs_assert(gap_end >= gap_start); | |
121 | ||
122 | gap_remains = gap_end - gap_start; | |
123 | if (!gap_remains) | |
124 | return 0; | |
125 | gap_pos = gap_start; | |
126 | written = 0; | |
127 | while (c->enext) { | |
128 | len = ubifs_idx_node_sz(c, c->enext->child_cnt); | |
129 | if (len < gap_remains) { | |
130 | struct ubifs_znode *znode = c->enext; | |
131 | const int alen = ALIGN(len, 8); | |
132 | int err; | |
133 | ||
134 | ubifs_assert(alen <= gap_remains); | |
135 | err = make_idx_node(c, c->ileb_buf + gap_pos, znode, | |
136 | lnum, gap_pos, len); | |
137 | if (err) | |
138 | return err; | |
139 | gap_remains -= alen; | |
140 | gap_pos += alen; | |
141 | c->enext = znode->cnext; | |
142 | if (c->enext == c->cnext) | |
143 | c->enext = NULL; | |
144 | written += 1; | |
145 | } else | |
146 | break; | |
147 | } | |
148 | if (gap_end == c->leb_size) { | |
149 | c->ileb_len = ALIGN(gap_pos, c->min_io_size); | |
150 | /* Pad to end of min_io_size */ | |
151 | pad_len = c->ileb_len - gap_pos; | |
152 | } else | |
153 | /* Pad to end of gap */ | |
154 | pad_len = gap_remains; | |
155 | dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d", | |
156 | lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len); | |
157 | ubifs_pad(c, c->ileb_buf + gap_pos, pad_len); | |
158 | *dirt += pad_len; | |
159 | return written; | |
160 | } | |
161 | ||
162 | /** | |
163 | * find_old_idx - find an index node obsoleted since the last commit start. | |
164 | * @c: UBIFS file-system description object | |
165 | * @lnum: LEB number of obsoleted index node | |
166 | * @offs: offset of obsoleted index node | |
167 | * | |
168 | * Returns %1 if found and %0 otherwise. | |
169 | */ | |
170 | static int find_old_idx(struct ubifs_info *c, int lnum, int offs) | |
171 | { | |
172 | struct ubifs_old_idx *o; | |
173 | struct rb_node *p; | |
174 | ||
175 | p = c->old_idx.rb_node; | |
176 | while (p) { | |
177 | o = rb_entry(p, struct ubifs_old_idx, rb); | |
178 | if (lnum < o->lnum) | |
179 | p = p->rb_left; | |
180 | else if (lnum > o->lnum) | |
181 | p = p->rb_right; | |
182 | else if (offs < o->offs) | |
183 | p = p->rb_left; | |
184 | else if (offs > o->offs) | |
185 | p = p->rb_right; | |
186 | else | |
187 | return 1; | |
188 | } | |
189 | return 0; | |
190 | } | |
191 | ||
192 | /** | |
193 | * is_idx_node_in_use - determine if an index node can be overwritten. | |
194 | * @c: UBIFS file-system description object | |
195 | * @key: key of index node | |
196 | * @level: index node level | |
197 | * @lnum: LEB number of index node | |
198 | * @offs: offset of index node | |
199 | * | |
200 | * If @key / @lnum / @offs identify an index node that was not part of the old | |
201 | * index, then this function returns %0 (obsolete). Else if the index node was | |
202 | * part of the old index but is now dirty %1 is returned, else if it is clean %2 | |
203 | * is returned. A negative error code is returned on failure. | |
204 | */ | |
205 | static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key, | |
206 | int level, int lnum, int offs) | |
207 | { | |
208 | int ret; | |
209 | ||
210 | ret = is_idx_node_in_tnc(c, key, level, lnum, offs); | |
211 | if (ret < 0) | |
212 | return ret; /* Error code */ | |
213 | if (ret == 0) | |
214 | if (find_old_idx(c, lnum, offs)) | |
215 | return 1; | |
216 | return ret; | |
217 | } | |
218 | ||
219 | /** | |
220 | * layout_leb_in_gaps - layout index nodes using in-the-gaps method. | |
221 | * @c: UBIFS file-system description object | |
222 | * @p: return LEB number here | |
223 | * | |
224 | * This function lays out new index nodes for dirty znodes using in-the-gaps | |
225 | * method of TNC commit. | |
226 | * This function merely puts the next znode into the next gap, making no attempt | |
227 | * to try to maximise the number of znodes that fit. | |
228 | * This function returns the number of index nodes written into the gaps, or a | |
229 | * negative error code on failure. | |
230 | */ | |
231 | static int layout_leb_in_gaps(struct ubifs_info *c, int *p) | |
232 | { | |
233 | struct ubifs_scan_leb *sleb; | |
234 | struct ubifs_scan_node *snod; | |
235 | int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written; | |
236 | ||
237 | tot_written = 0; | |
238 | /* Get an index LEB with lots of obsolete index nodes */ | |
239 | lnum = ubifs_find_dirty_idx_leb(c); | |
240 | if (lnum < 0) | |
241 | /* | |
242 | * There also may be dirt in the index head that could be | |
243 | * filled, however we do not check there at present. | |
244 | */ | |
245 | return lnum; /* Error code */ | |
246 | *p = lnum; | |
247 | dbg_gc("LEB %d", lnum); | |
248 | /* | |
249 | * Scan the index LEB. We use the generic scan for this even though | |
250 | * it is more comprehensive and less efficient than is needed for this | |
251 | * purpose. | |
252 | */ | |
348709ba | 253 | sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0); |
1e51764a AB |
254 | c->ileb_len = 0; |
255 | if (IS_ERR(sleb)) | |
256 | return PTR_ERR(sleb); | |
257 | gap_start = 0; | |
258 | list_for_each_entry(snod, &sleb->nodes, list) { | |
259 | struct ubifs_idx_node *idx; | |
260 | int in_use, level; | |
261 | ||
262 | ubifs_assert(snod->type == UBIFS_IDX_NODE); | |
263 | idx = snod->node; | |
264 | key_read(c, ubifs_idx_key(c, idx), &snod->key); | |
265 | level = le16_to_cpu(idx->level); | |
266 | /* Determine if the index node is in use (not obsolete) */ | |
267 | in_use = is_idx_node_in_use(c, &snod->key, level, lnum, | |
268 | snod->offs); | |
269 | if (in_use < 0) { | |
270 | ubifs_scan_destroy(sleb); | |
271 | return in_use; /* Error code */ | |
272 | } | |
273 | if (in_use) { | |
274 | if (in_use == 1) | |
275 | dirt += ALIGN(snod->len, 8); | |
276 | /* | |
277 | * The obsolete index nodes form gaps that can be | |
278 | * overwritten. This gap has ended because we have | |
279 | * found an index node that is still in use | |
280 | * i.e. not obsolete | |
281 | */ | |
282 | gap_end = snod->offs; | |
283 | /* Try to fill gap */ | |
284 | written = fill_gap(c, lnum, gap_start, gap_end, &dirt); | |
285 | if (written < 0) { | |
286 | ubifs_scan_destroy(sleb); | |
287 | return written; /* Error code */ | |
288 | } | |
289 | tot_written += written; | |
290 | gap_start = ALIGN(snod->offs + snod->len, 8); | |
291 | } | |
292 | } | |
293 | ubifs_scan_destroy(sleb); | |
294 | c->ileb_len = c->leb_size; | |
295 | gap_end = c->leb_size; | |
296 | /* Try to fill gap */ | |
297 | written = fill_gap(c, lnum, gap_start, gap_end, &dirt); | |
298 | if (written < 0) | |
299 | return written; /* Error code */ | |
300 | tot_written += written; | |
301 | if (tot_written == 0) { | |
302 | struct ubifs_lprops lp; | |
303 | ||
304 | dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); | |
305 | err = ubifs_read_one_lp(c, lnum, &lp); | |
306 | if (err) | |
307 | return err; | |
308 | if (lp.free == c->leb_size) { | |
309 | /* | |
310 | * We must have snatched this LEB from the idx_gc list | |
311 | * so we need to correct the free and dirty space. | |
312 | */ | |
313 | err = ubifs_change_one_lp(c, lnum, | |
314 | c->leb_size - c->ileb_len, | |
315 | dirt, 0, 0, 0); | |
316 | if (err) | |
317 | return err; | |
318 | } | |
319 | return 0; | |
320 | } | |
321 | err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt, | |
322 | 0, 0, 0); | |
323 | if (err) | |
324 | return err; | |
325 | err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len, | |
326 | UBI_SHORTTERM); | |
327 | if (err) | |
328 | return err; | |
329 | dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); | |
330 | return tot_written; | |
331 | } | |
332 | ||
333 | /** | |
334 | * get_leb_cnt - calculate the number of empty LEBs needed to commit. | |
335 | * @c: UBIFS file-system description object | |
336 | * @cnt: number of znodes to commit | |
337 | * | |
338 | * This function returns the number of empty LEBs needed to commit @cnt znodes | |
339 | * to the current index head. The number is not exact and may be more than | |
340 | * needed. | |
341 | */ | |
342 | static int get_leb_cnt(struct ubifs_info *c, int cnt) | |
343 | { | |
344 | int d; | |
345 | ||
346 | /* Assume maximum index node size (i.e. overestimate space needed) */ | |
347 | cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz; | |
348 | if (cnt < 0) | |
349 | cnt = 0; | |
350 | d = c->leb_size / c->max_idx_node_sz; | |
351 | return DIV_ROUND_UP(cnt, d); | |
352 | } | |
353 | ||
354 | /** | |
355 | * layout_in_gaps - in-the-gaps method of committing TNC. | |
356 | * @c: UBIFS file-system description object | |
357 | * @cnt: number of dirty znodes to commit. | |
358 | * | |
359 | * This function lays out new index nodes for dirty znodes using in-the-gaps | |
360 | * method of TNC commit. | |
361 | * | |
362 | * This function returns %0 on success and a negative error code on failure. | |
363 | */ | |
364 | static int layout_in_gaps(struct ubifs_info *c, int cnt) | |
365 | { | |
366 | int err, leb_needed_cnt, written, *p; | |
367 | ||
368 | dbg_gc("%d znodes to write", cnt); | |
369 | ||
370 | c->gap_lebs = kmalloc(sizeof(int) * (c->lst.idx_lebs + 1), GFP_NOFS); | |
371 | if (!c->gap_lebs) | |
372 | return -ENOMEM; | |
373 | ||
374 | p = c->gap_lebs; | |
375 | do { | |
376 | ubifs_assert(p < c->gap_lebs + sizeof(int) * c->lst.idx_lebs); | |
377 | written = layout_leb_in_gaps(c, p); | |
378 | if (written < 0) { | |
379 | err = written; | |
0010f18a AB |
380 | if (err != -ENOSPC) { |
381 | kfree(c->gap_lebs); | |
382 | c->gap_lebs = NULL; | |
383 | return err; | |
1e51764a | 384 | } |
8d7819b4 | 385 | if (!dbg_is_chk_index(c)) { |
0010f18a AB |
386 | /* |
387 | * Do not print scary warnings if the debugging | |
388 | * option which forces in-the-gaps is enabled. | |
389 | */ | |
bc3f07f0 | 390 | ubifs_warn("out of space"); |
edf6be24 AB |
391 | ubifs_dump_budg(c, &c->bi); |
392 | ubifs_dump_lprops(c); | |
0010f18a AB |
393 | } |
394 | /* Try to commit anyway */ | |
395 | err = 0; | |
396 | break; | |
1e51764a AB |
397 | } |
398 | p++; | |
399 | cnt -= written; | |
400 | leb_needed_cnt = get_leb_cnt(c, cnt); | |
401 | dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt, | |
402 | leb_needed_cnt, c->ileb_cnt); | |
403 | } while (leb_needed_cnt > c->ileb_cnt); | |
404 | ||
405 | *p = -1; | |
406 | return 0; | |
407 | } | |
408 | ||
409 | /** | |
410 | * layout_in_empty_space - layout index nodes in empty space. | |
411 | * @c: UBIFS file-system description object | |
412 | * | |
413 | * This function lays out new index nodes for dirty znodes using empty LEBs. | |
414 | * | |
415 | * This function returns %0 on success and a negative error code on failure. | |
416 | */ | |
417 | static int layout_in_empty_space(struct ubifs_info *c) | |
418 | { | |
419 | struct ubifs_znode *znode, *cnext, *zp; | |
420 | int lnum, offs, len, next_len, buf_len, buf_offs, used, avail; | |
421 | int wlen, blen, err; | |
422 | ||
423 | cnext = c->enext; | |
424 | if (!cnext) | |
425 | return 0; | |
426 | ||
427 | lnum = c->ihead_lnum; | |
428 | buf_offs = c->ihead_offs; | |
429 | ||
430 | buf_len = ubifs_idx_node_sz(c, c->fanout); | |
431 | buf_len = ALIGN(buf_len, c->min_io_size); | |
432 | used = 0; | |
433 | avail = buf_len; | |
434 | ||
435 | /* Ensure there is enough room for first write */ | |
436 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
437 | if (buf_offs + next_len > c->leb_size) | |
438 | lnum = -1; | |
439 | ||
440 | while (1) { | |
441 | znode = cnext; | |
442 | ||
443 | len = ubifs_idx_node_sz(c, znode->child_cnt); | |
444 | ||
445 | /* Determine the index node position */ | |
446 | if (lnum == -1) { | |
447 | if (c->ileb_nxt >= c->ileb_cnt) { | |
448 | ubifs_err("out of space"); | |
449 | return -ENOSPC; | |
450 | } | |
451 | lnum = c->ilebs[c->ileb_nxt++]; | |
452 | buf_offs = 0; | |
453 | used = 0; | |
454 | avail = buf_len; | |
455 | } | |
456 | ||
457 | offs = buf_offs + used; | |
458 | ||
459 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
460 | znode->lnum = lnum; | |
461 | znode->offs = offs; | |
462 | znode->len = len; | |
463 | #endif | |
464 | ||
465 | /* Update the parent */ | |
466 | zp = znode->parent; | |
467 | if (zp) { | |
468 | struct ubifs_zbranch *zbr; | |
469 | int i; | |
470 | ||
471 | i = znode->iip; | |
472 | zbr = &zp->zbranch[i]; | |
473 | zbr->lnum = lnum; | |
474 | zbr->offs = offs; | |
475 | zbr->len = len; | |
476 | } else { | |
477 | c->zroot.lnum = lnum; | |
478 | c->zroot.offs = offs; | |
479 | c->zroot.len = len; | |
480 | } | |
481 | c->calc_idx_sz += ALIGN(len, 8); | |
482 | ||
483 | /* | |
484 | * Once lprops is updated, we can decrease the dirty znode count | |
485 | * but it is easier to just do it here. | |
486 | */ | |
487 | atomic_long_dec(&c->dirty_zn_cnt); | |
488 | ||
489 | /* | |
490 | * Calculate the next index node length to see if there is | |
491 | * enough room for it | |
492 | */ | |
493 | cnext = znode->cnext; | |
494 | if (cnext == c->cnext) | |
495 | next_len = 0; | |
496 | else | |
497 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
498 | ||
1e51764a AB |
499 | /* Update buffer positions */ |
500 | wlen = used + len; | |
501 | used += ALIGN(len, 8); | |
502 | avail -= ALIGN(len, 8); | |
503 | ||
504 | if (next_len != 0 && | |
505 | buf_offs + used + next_len <= c->leb_size && | |
506 | avail > 0) | |
507 | continue; | |
508 | ||
509 | if (avail <= 0 && next_len && | |
510 | buf_offs + used + next_len <= c->leb_size) | |
511 | blen = buf_len; | |
512 | else | |
513 | blen = ALIGN(wlen, c->min_io_size); | |
514 | ||
515 | /* The buffer is full or there are no more znodes to do */ | |
516 | buf_offs += blen; | |
517 | if (next_len) { | |
518 | if (buf_offs + next_len > c->leb_size) { | |
519 | err = ubifs_update_one_lp(c, lnum, | |
520 | c->leb_size - buf_offs, blen - used, | |
521 | 0, 0); | |
522 | if (err) | |
523 | return err; | |
524 | lnum = -1; | |
525 | } | |
526 | used -= blen; | |
527 | if (used < 0) | |
528 | used = 0; | |
529 | avail = buf_len - used; | |
530 | continue; | |
531 | } | |
532 | err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs, | |
533 | blen - used, 0, 0); | |
534 | if (err) | |
535 | return err; | |
536 | break; | |
537 | } | |
538 | ||
539 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
17c2f9f8 AB |
540 | c->dbg->new_ihead_lnum = lnum; |
541 | c->dbg->new_ihead_offs = buf_offs; | |
1e51764a AB |
542 | #endif |
543 | ||
544 | return 0; | |
545 | } | |
546 | ||
547 | /** | |
548 | * layout_commit - determine positions of index nodes to commit. | |
549 | * @c: UBIFS file-system description object | |
550 | * @no_space: indicates that insufficient empty LEBs were allocated | |
551 | * @cnt: number of znodes to commit | |
552 | * | |
553 | * Calculate and update the positions of index nodes to commit. If there were | |
554 | * an insufficient number of empty LEBs allocated, then index nodes are placed | |
555 | * into the gaps created by obsolete index nodes in non-empty index LEBs. For | |
556 | * this purpose, an obsolete index node is one that was not in the index as at | |
557 | * the end of the last commit. To write "in-the-gaps" requires that those index | |
558 | * LEBs are updated atomically in-place. | |
559 | */ | |
560 | static int layout_commit(struct ubifs_info *c, int no_space, int cnt) | |
561 | { | |
562 | int err; | |
563 | ||
564 | if (no_space) { | |
565 | err = layout_in_gaps(c, cnt); | |
566 | if (err) | |
567 | return err; | |
568 | } | |
569 | err = layout_in_empty_space(c); | |
570 | return err; | |
571 | } | |
572 | ||
573 | /** | |
574 | * find_first_dirty - find first dirty znode. | |
575 | * @znode: znode to begin searching from | |
576 | */ | |
577 | static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode) | |
578 | { | |
579 | int i, cont; | |
580 | ||
581 | if (!znode) | |
582 | return NULL; | |
583 | ||
584 | while (1) { | |
585 | if (znode->level == 0) { | |
586 | if (ubifs_zn_dirty(znode)) | |
587 | return znode; | |
588 | return NULL; | |
589 | } | |
590 | cont = 0; | |
591 | for (i = 0; i < znode->child_cnt; i++) { | |
592 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; | |
593 | ||
594 | if (zbr->znode && ubifs_zn_dirty(zbr->znode)) { | |
595 | znode = zbr->znode; | |
596 | cont = 1; | |
597 | break; | |
598 | } | |
599 | } | |
600 | if (!cont) { | |
601 | if (ubifs_zn_dirty(znode)) | |
602 | return znode; | |
603 | return NULL; | |
604 | } | |
605 | } | |
606 | } | |
607 | ||
608 | /** | |
609 | * find_next_dirty - find next dirty znode. | |
610 | * @znode: znode to begin searching from | |
611 | */ | |
612 | static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode) | |
613 | { | |
614 | int n = znode->iip + 1; | |
615 | ||
616 | znode = znode->parent; | |
617 | if (!znode) | |
618 | return NULL; | |
619 | for (; n < znode->child_cnt; n++) { | |
620 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; | |
621 | ||
622 | if (zbr->znode && ubifs_zn_dirty(zbr->znode)) | |
623 | return find_first_dirty(zbr->znode); | |
624 | } | |
625 | return znode; | |
626 | } | |
627 | ||
628 | /** | |
629 | * get_znodes_to_commit - create list of dirty znodes to commit. | |
630 | * @c: UBIFS file-system description object | |
631 | * | |
632 | * This function returns the number of znodes to commit. | |
633 | */ | |
634 | static int get_znodes_to_commit(struct ubifs_info *c) | |
635 | { | |
636 | struct ubifs_znode *znode, *cnext; | |
637 | int cnt = 0; | |
638 | ||
639 | c->cnext = find_first_dirty(c->zroot.znode); | |
640 | znode = c->enext = c->cnext; | |
641 | if (!znode) { | |
642 | dbg_cmt("no znodes to commit"); | |
643 | return 0; | |
644 | } | |
645 | cnt += 1; | |
646 | while (1) { | |
f42eed7c | 647 | ubifs_assert(!ubifs_zn_cow(znode)); |
1e51764a AB |
648 | __set_bit(COW_ZNODE, &znode->flags); |
649 | znode->alt = 0; | |
650 | cnext = find_next_dirty(znode); | |
651 | if (!cnext) { | |
652 | znode->cnext = c->cnext; | |
653 | break; | |
654 | } | |
655 | znode->cnext = cnext; | |
656 | znode = cnext; | |
657 | cnt += 1; | |
658 | } | |
659 | dbg_cmt("committing %d znodes", cnt); | |
660 | ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt)); | |
661 | return cnt; | |
662 | } | |
663 | ||
664 | /** | |
665 | * alloc_idx_lebs - allocate empty LEBs to be used to commit. | |
666 | * @c: UBIFS file-system description object | |
667 | * @cnt: number of znodes to commit | |
668 | * | |
669 | * This function returns %-ENOSPC if it cannot allocate a sufficient number of | |
670 | * empty LEBs. %0 is returned on success, otherwise a negative error code | |
671 | * is returned. | |
672 | */ | |
673 | static int alloc_idx_lebs(struct ubifs_info *c, int cnt) | |
674 | { | |
675 | int i, leb_cnt, lnum; | |
676 | ||
677 | c->ileb_cnt = 0; | |
678 | c->ileb_nxt = 0; | |
679 | leb_cnt = get_leb_cnt(c, cnt); | |
680 | dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt); | |
681 | if (!leb_cnt) | |
682 | return 0; | |
683 | c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS); | |
684 | if (!c->ilebs) | |
685 | return -ENOMEM; | |
686 | for (i = 0; i < leb_cnt; i++) { | |
687 | lnum = ubifs_find_free_leb_for_idx(c); | |
688 | if (lnum < 0) | |
689 | return lnum; | |
690 | c->ilebs[c->ileb_cnt++] = lnum; | |
691 | dbg_cmt("LEB %d", lnum); | |
692 | } | |
8d7819b4 | 693 | if (dbg_is_chk_index(c) && !(random32() & 7)) |
1e51764a AB |
694 | return -ENOSPC; |
695 | return 0; | |
696 | } | |
697 | ||
698 | /** | |
699 | * free_unused_idx_lebs - free unused LEBs that were allocated for the commit. | |
700 | * @c: UBIFS file-system description object | |
701 | * | |
702 | * It is possible that we allocate more empty LEBs for the commit than we need. | |
703 | * This functions frees the surplus. | |
704 | * | |
705 | * This function returns %0 on success and a negative error code on failure. | |
706 | */ | |
707 | static int free_unused_idx_lebs(struct ubifs_info *c) | |
708 | { | |
709 | int i, err = 0, lnum, er; | |
710 | ||
711 | for (i = c->ileb_nxt; i < c->ileb_cnt; i++) { | |
712 | lnum = c->ilebs[i]; | |
713 | dbg_cmt("LEB %d", lnum); | |
714 | er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0, | |
715 | LPROPS_INDEX | LPROPS_TAKEN, 0); | |
716 | if (!err) | |
717 | err = er; | |
718 | } | |
719 | return err; | |
720 | } | |
721 | ||
722 | /** | |
723 | * free_idx_lebs - free unused LEBs after commit end. | |
724 | * @c: UBIFS file-system description object | |
725 | * | |
726 | * This function returns %0 on success and a negative error code on failure. | |
727 | */ | |
728 | static int free_idx_lebs(struct ubifs_info *c) | |
729 | { | |
730 | int err; | |
731 | ||
732 | err = free_unused_idx_lebs(c); | |
733 | kfree(c->ilebs); | |
734 | c->ilebs = NULL; | |
735 | return err; | |
736 | } | |
737 | ||
738 | /** | |
739 | * ubifs_tnc_start_commit - start TNC commit. | |
740 | * @c: UBIFS file-system description object | |
741 | * @zroot: new index root position is returned here | |
742 | * | |
743 | * This function prepares the list of indexing nodes to commit and lays out | |
744 | * their positions on flash. If there is not enough free space it uses the | |
745 | * in-gap commit method. Returns zero in case of success and a negative error | |
746 | * code in case of failure. | |
747 | */ | |
748 | int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot) | |
749 | { | |
750 | int err = 0, cnt; | |
751 | ||
752 | mutex_lock(&c->tnc_mutex); | |
753 | err = dbg_check_tnc(c, 1); | |
754 | if (err) | |
755 | goto out; | |
756 | cnt = get_znodes_to_commit(c); | |
757 | if (cnt != 0) { | |
758 | int no_space = 0; | |
759 | ||
760 | err = alloc_idx_lebs(c, cnt); | |
761 | if (err == -ENOSPC) | |
762 | no_space = 1; | |
763 | else if (err) | |
764 | goto out_free; | |
765 | err = layout_commit(c, no_space, cnt); | |
766 | if (err) | |
767 | goto out_free; | |
768 | ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0); | |
769 | err = free_unused_idx_lebs(c); | |
770 | if (err) | |
771 | goto out; | |
772 | } | |
773 | destroy_old_idx(c); | |
774 | memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch)); | |
775 | ||
776 | err = ubifs_save_dirty_idx_lnums(c); | |
777 | if (err) | |
778 | goto out; | |
779 | ||
780 | spin_lock(&c->space_lock); | |
781 | /* | |
782 | * Although we have not finished committing yet, update size of the | |
b137545c | 783 | * committed index ('c->bi.old_idx_sz') and zero out the index growth |
1e51764a AB |
784 | * budget. It is OK to do this now, because we've reserved all the |
785 | * space which is needed to commit the index, and it is save for the | |
786 | * budgeting subsystem to assume the index is already committed, | |
787 | * even though it is not. | |
788 | */ | |
b137545c AB |
789 | ubifs_assert(c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c)); |
790 | c->bi.old_idx_sz = c->calc_idx_sz; | |
791 | c->bi.uncommitted_idx = 0; | |
792 | c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c); | |
1e51764a AB |
793 | spin_unlock(&c->space_lock); |
794 | mutex_unlock(&c->tnc_mutex); | |
795 | ||
796 | dbg_cmt("number of index LEBs %d", c->lst.idx_lebs); | |
797 | dbg_cmt("size of index %llu", c->calc_idx_sz); | |
798 | return err; | |
799 | ||
800 | out_free: | |
801 | free_idx_lebs(c); | |
802 | out: | |
803 | mutex_unlock(&c->tnc_mutex); | |
804 | return err; | |
805 | } | |
806 | ||
807 | /** | |
808 | * write_index - write index nodes. | |
809 | * @c: UBIFS file-system description object | |
810 | * | |
811 | * This function writes the index nodes whose positions were laid out in the | |
812 | * layout_in_empty_space function. | |
813 | */ | |
814 | static int write_index(struct ubifs_info *c) | |
815 | { | |
816 | struct ubifs_idx_node *idx; | |
817 | struct ubifs_znode *znode, *cnext; | |
818 | int i, lnum, offs, len, next_len, buf_len, buf_offs, used; | |
1f42596e | 819 | int avail, wlen, err, lnum_pos = 0, blen, nxt_offs; |
1e51764a AB |
820 | |
821 | cnext = c->enext; | |
822 | if (!cnext) | |
823 | return 0; | |
824 | ||
825 | /* | |
826 | * Always write index nodes to the index head so that index nodes and | |
827 | * other types of nodes are never mixed in the same erase block. | |
828 | */ | |
829 | lnum = c->ihead_lnum; | |
830 | buf_offs = c->ihead_offs; | |
831 | ||
832 | /* Allocate commit buffer */ | |
833 | buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size); | |
834 | used = 0; | |
835 | avail = buf_len; | |
836 | ||
837 | /* Ensure there is enough room for first write */ | |
838 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
839 | if (buf_offs + next_len > c->leb_size) { | |
840 | err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0, | |
841 | LPROPS_TAKEN); | |
842 | if (err) | |
843 | return err; | |
844 | lnum = -1; | |
845 | } | |
846 | ||
847 | while (1) { | |
848 | cond_resched(); | |
849 | ||
850 | znode = cnext; | |
851 | idx = c->cbuf + used; | |
852 | ||
853 | /* Make index node */ | |
854 | idx->ch.node_type = UBIFS_IDX_NODE; | |
855 | idx->child_cnt = cpu_to_le16(znode->child_cnt); | |
856 | idx->level = cpu_to_le16(znode->level); | |
857 | for (i = 0; i < znode->child_cnt; i++) { | |
858 | struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); | |
859 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; | |
860 | ||
861 | key_write_idx(c, &zbr->key, &br->key); | |
862 | br->lnum = cpu_to_le32(zbr->lnum); | |
863 | br->offs = cpu_to_le32(zbr->offs); | |
864 | br->len = cpu_to_le32(zbr->len); | |
865 | if (!zbr->lnum || !zbr->len) { | |
866 | ubifs_err("bad ref in znode"); | |
edf6be24 | 867 | ubifs_dump_znode(c, znode); |
1e51764a | 868 | if (zbr->znode) |
edf6be24 | 869 | ubifs_dump_znode(c, zbr->znode); |
1e51764a AB |
870 | } |
871 | } | |
872 | len = ubifs_idx_node_sz(c, znode->child_cnt); | |
873 | ubifs_prepare_node(c, idx, len, 0); | |
874 | ||
875 | /* Determine the index node position */ | |
876 | if (lnum == -1) { | |
877 | lnum = c->ilebs[lnum_pos++]; | |
878 | buf_offs = 0; | |
879 | used = 0; | |
880 | avail = buf_len; | |
881 | } | |
882 | offs = buf_offs + used; | |
883 | ||
884 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
885 | if (lnum != znode->lnum || offs != znode->offs || | |
886 | len != znode->len) { | |
887 | ubifs_err("inconsistent znode posn"); | |
888 | return -EINVAL; | |
889 | } | |
890 | #endif | |
891 | ||
892 | /* Grab some stuff from znode while we still can */ | |
893 | cnext = znode->cnext; | |
894 | ||
895 | ubifs_assert(ubifs_zn_dirty(znode)); | |
f42eed7c | 896 | ubifs_assert(ubifs_zn_cow(znode)); |
1e51764a AB |
897 | |
898 | /* | |
899 | * It is important that other threads should see %DIRTY_ZNODE | |
900 | * flag cleared before %COW_ZNODE. Specifically, it matters in | |
901 | * the 'dirty_cow_znode()' function. This is the reason for the | |
902 | * first barrier. Also, we want the bit changes to be seen to | |
903 | * other threads ASAP, to avoid unnecesarry copying, which is | |
904 | * the reason for the second barrier. | |
905 | */ | |
906 | clear_bit(DIRTY_ZNODE, &znode->flags); | |
907 | smp_mb__before_clear_bit(); | |
908 | clear_bit(COW_ZNODE, &znode->flags); | |
909 | smp_mb__after_clear_bit(); | |
910 | ||
06b282a4 AB |
911 | /* |
912 | * We have marked the znode as clean but have not updated the | |
913 | * @c->clean_zn_cnt counter. If this znode becomes dirty again | |
914 | * before 'free_obsolete_znodes()' is called, then | |
915 | * @c->clean_zn_cnt will be decremented before it gets | |
916 | * incremented (resulting in 2 decrements for the same znode). | |
917 | * This means that @c->clean_zn_cnt may become negative for a | |
918 | * while. | |
919 | * | |
920 | * Q: why we cannot increment @c->clean_zn_cnt? | |
921 | * A: because we do not have the @c->tnc_mutex locked, and the | |
922 | * following code would be racy and buggy: | |
923 | * | |
924 | * if (!ubifs_zn_obsolete(znode)) { | |
925 | * atomic_long_inc(&c->clean_zn_cnt); | |
926 | * atomic_long_inc(&ubifs_clean_zn_cnt); | |
927 | * } | |
928 | * | |
929 | * Thus, we just delay the @c->clean_zn_cnt update until we | |
930 | * have the mutex locked. | |
931 | */ | |
932 | ||
1e51764a AB |
933 | /* Do not access znode from this point on */ |
934 | ||
935 | /* Update buffer positions */ | |
936 | wlen = used + len; | |
937 | used += ALIGN(len, 8); | |
938 | avail -= ALIGN(len, 8); | |
939 | ||
940 | /* | |
941 | * Calculate the next index node length to see if there is | |
942 | * enough room for it | |
943 | */ | |
944 | if (cnext == c->cnext) | |
945 | next_len = 0; | |
946 | else | |
947 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
948 | ||
1f42596e AB |
949 | nxt_offs = buf_offs + used + next_len; |
950 | if (next_len && nxt_offs <= c->leb_size) { | |
951 | if (avail > 0) | |
1e51764a | 952 | continue; |
1f42596e AB |
953 | else |
954 | blen = buf_len; | |
1e51764a | 955 | } else { |
1f42596e AB |
956 | wlen = ALIGN(wlen, 8); |
957 | blen = ALIGN(wlen, c->min_io_size); | |
958 | ubifs_pad(c, c->cbuf + wlen, blen - wlen); | |
959 | } | |
960 | ||
961 | /* The buffer is full or there are no more znodes to do */ | |
962 | err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, blen, | |
963 | UBI_SHORTTERM); | |
964 | if (err) | |
965 | return err; | |
966 | buf_offs += blen; | |
967 | if (next_len) { | |
968 | if (nxt_offs > c->leb_size) { | |
969 | err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, | |
970 | 0, LPROPS_TAKEN); | |
971 | if (err) | |
972 | return err; | |
973 | lnum = -1; | |
1e51764a | 974 | } |
1f42596e AB |
975 | used -= blen; |
976 | if (used < 0) | |
977 | used = 0; | |
978 | avail = buf_len - used; | |
979 | memmove(c->cbuf, c->cbuf + blen, used); | |
980 | continue; | |
1e51764a AB |
981 | } |
982 | break; | |
983 | } | |
984 | ||
985 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
17c2f9f8 AB |
986 | if (lnum != c->dbg->new_ihead_lnum || |
987 | buf_offs != c->dbg->new_ihead_offs) { | |
1e51764a AB |
988 | ubifs_err("inconsistent ihead"); |
989 | return -EINVAL; | |
990 | } | |
991 | #endif | |
992 | ||
993 | c->ihead_lnum = lnum; | |
994 | c->ihead_offs = buf_offs; | |
995 | ||
996 | return 0; | |
997 | } | |
998 | ||
999 | /** | |
1000 | * free_obsolete_znodes - free obsolete znodes. | |
1001 | * @c: UBIFS file-system description object | |
1002 | * | |
1003 | * At the end of commit end, obsolete znodes are freed. | |
1004 | */ | |
1005 | static void free_obsolete_znodes(struct ubifs_info *c) | |
1006 | { | |
1007 | struct ubifs_znode *znode, *cnext; | |
1008 | ||
1009 | cnext = c->cnext; | |
1010 | do { | |
1011 | znode = cnext; | |
1012 | cnext = znode->cnext; | |
f42eed7c | 1013 | if (ubifs_zn_obsolete(znode)) |
1e51764a AB |
1014 | kfree(znode); |
1015 | else { | |
1016 | znode->cnext = NULL; | |
1017 | atomic_long_inc(&c->clean_zn_cnt); | |
1018 | atomic_long_inc(&ubifs_clean_zn_cnt); | |
1019 | } | |
1020 | } while (cnext != c->cnext); | |
1021 | } | |
1022 | ||
1023 | /** | |
1024 | * return_gap_lebs - return LEBs used by the in-gap commit method. | |
1025 | * @c: UBIFS file-system description object | |
1026 | * | |
1027 | * This function clears the "taken" flag for the LEBs which were used by the | |
1028 | * "commit in-the-gaps" method. | |
1029 | */ | |
1030 | static int return_gap_lebs(struct ubifs_info *c) | |
1031 | { | |
1032 | int *p, err; | |
1033 | ||
1034 | if (!c->gap_lebs) | |
1035 | return 0; | |
1036 | ||
1037 | dbg_cmt(""); | |
1038 | for (p = c->gap_lebs; *p != -1; p++) { | |
1039 | err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0, | |
1040 | LPROPS_TAKEN, 0); | |
1041 | if (err) | |
1042 | return err; | |
1043 | } | |
1044 | ||
1045 | kfree(c->gap_lebs); | |
1046 | c->gap_lebs = NULL; | |
1047 | return 0; | |
1048 | } | |
1049 | ||
1050 | /** | |
1051 | * ubifs_tnc_end_commit - update the TNC for commit end. | |
1052 | * @c: UBIFS file-system description object | |
1053 | * | |
1054 | * Write the dirty znodes. | |
1055 | */ | |
1056 | int ubifs_tnc_end_commit(struct ubifs_info *c) | |
1057 | { | |
1058 | int err; | |
1059 | ||
1060 | if (!c->cnext) | |
1061 | return 0; | |
1062 | ||
1063 | err = return_gap_lebs(c); | |
1064 | if (err) | |
1065 | return err; | |
1066 | ||
1067 | err = write_index(c); | |
1068 | if (err) | |
1069 | return err; | |
1070 | ||
1071 | mutex_lock(&c->tnc_mutex); | |
1072 | ||
1073 | dbg_cmt("TNC height is %d", c->zroot.znode->level + 1); | |
1074 | ||
1075 | free_obsolete_znodes(c); | |
1076 | ||
1077 | c->cnext = NULL; | |
1078 | kfree(c->ilebs); | |
1079 | c->ilebs = NULL; | |
1080 | ||
1081 | mutex_unlock(&c->tnc_mutex); | |
1082 | ||
1083 | return 0; | |
1084 | } |