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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 | ||
25 | #include "ubifs.h" | |
26 | ||
27 | /** | |
28 | * make_idx_node - make an index node for fill-the-gaps method of TNC commit. | |
29 | * @c: UBIFS file-system description object | |
30 | * @idx: buffer in which to place new index node | |
31 | * @znode: znode from which to make new index node | |
32 | * @lnum: LEB number where new index node will be written | |
33 | * @offs: offset where new index node will be written | |
34 | * @len: length of new index node | |
35 | */ | |
36 | static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx, | |
37 | struct ubifs_znode *znode, int lnum, int offs, int len) | |
38 | { | |
39 | struct ubifs_znode *zp; | |
40 | int i, err; | |
41 | ||
42 | /* Make index node */ | |
43 | idx->ch.node_type = UBIFS_IDX_NODE; | |
44 | idx->child_cnt = cpu_to_le16(znode->child_cnt); | |
45 | idx->level = cpu_to_le16(znode->level); | |
46 | for (i = 0; i < znode->child_cnt; i++) { | |
47 | struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); | |
48 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; | |
49 | ||
50 | key_write_idx(c, &zbr->key, &br->key); | |
51 | br->lnum = cpu_to_le32(zbr->lnum); | |
52 | br->offs = cpu_to_le32(zbr->offs); | |
53 | br->len = cpu_to_le32(zbr->len); | |
54 | if (!zbr->lnum || !zbr->len) { | |
55 | ubifs_err("bad ref in znode"); | |
56 | dbg_dump_znode(c, znode); | |
57 | if (zbr->znode) | |
58 | dbg_dump_znode(c, zbr->znode); | |
59 | } | |
60 | } | |
61 | ubifs_prepare_node(c, idx, len, 0); | |
62 | ||
63 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
64 | znode->lnum = lnum; | |
65 | znode->offs = offs; | |
66 | znode->len = len; | |
67 | #endif | |
68 | ||
69 | err = insert_old_idx_znode(c, znode); | |
70 | ||
71 | /* Update the parent */ | |
72 | zp = znode->parent; | |
73 | if (zp) { | |
74 | struct ubifs_zbranch *zbr; | |
75 | ||
76 | zbr = &zp->zbranch[znode->iip]; | |
77 | zbr->lnum = lnum; | |
78 | zbr->offs = offs; | |
79 | zbr->len = len; | |
80 | } else { | |
81 | c->zroot.lnum = lnum; | |
82 | c->zroot.offs = offs; | |
83 | c->zroot.len = len; | |
84 | } | |
85 | c->calc_idx_sz += ALIGN(len, 8); | |
86 | ||
87 | atomic_long_dec(&c->dirty_zn_cnt); | |
88 | ||
89 | ubifs_assert(ubifs_zn_dirty(znode)); | |
90 | ubifs_assert(test_bit(COW_ZNODE, &znode->flags)); | |
91 | ||
92 | __clear_bit(DIRTY_ZNODE, &znode->flags); | |
93 | __clear_bit(COW_ZNODE, &znode->flags); | |
94 | ||
95 | return err; | |
96 | } | |
97 | ||
98 | /** | |
99 | * fill_gap - make index nodes in gaps in dirty index LEBs. | |
100 | * @c: UBIFS file-system description object | |
101 | * @lnum: LEB number that gap appears in | |
102 | * @gap_start: offset of start of gap | |
103 | * @gap_end: offset of end of gap | |
104 | * @dirt: adds dirty space to this | |
105 | * | |
106 | * This function returns the number of index nodes written into the gap. | |
107 | */ | |
108 | static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end, | |
109 | int *dirt) | |
110 | { | |
111 | int len, gap_remains, gap_pos, written, pad_len; | |
112 | ||
113 | ubifs_assert((gap_start & 7) == 0); | |
114 | ubifs_assert((gap_end & 7) == 0); | |
115 | ubifs_assert(gap_end >= gap_start); | |
116 | ||
117 | gap_remains = gap_end - gap_start; | |
118 | if (!gap_remains) | |
119 | return 0; | |
120 | gap_pos = gap_start; | |
121 | written = 0; | |
122 | while (c->enext) { | |
123 | len = ubifs_idx_node_sz(c, c->enext->child_cnt); | |
124 | if (len < gap_remains) { | |
125 | struct ubifs_znode *znode = c->enext; | |
126 | const int alen = ALIGN(len, 8); | |
127 | int err; | |
128 | ||
129 | ubifs_assert(alen <= gap_remains); | |
130 | err = make_idx_node(c, c->ileb_buf + gap_pos, znode, | |
131 | lnum, gap_pos, len); | |
132 | if (err) | |
133 | return err; | |
134 | gap_remains -= alen; | |
135 | gap_pos += alen; | |
136 | c->enext = znode->cnext; | |
137 | if (c->enext == c->cnext) | |
138 | c->enext = NULL; | |
139 | written += 1; | |
140 | } else | |
141 | break; | |
142 | } | |
143 | if (gap_end == c->leb_size) { | |
144 | c->ileb_len = ALIGN(gap_pos, c->min_io_size); | |
145 | /* Pad to end of min_io_size */ | |
146 | pad_len = c->ileb_len - gap_pos; | |
147 | } else | |
148 | /* Pad to end of gap */ | |
149 | pad_len = gap_remains; | |
150 | dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d", | |
151 | lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len); | |
152 | ubifs_pad(c, c->ileb_buf + gap_pos, pad_len); | |
153 | *dirt += pad_len; | |
154 | return written; | |
155 | } | |
156 | ||
157 | /** | |
158 | * find_old_idx - find an index node obsoleted since the last commit start. | |
159 | * @c: UBIFS file-system description object | |
160 | * @lnum: LEB number of obsoleted index node | |
161 | * @offs: offset of obsoleted index node | |
162 | * | |
163 | * Returns %1 if found and %0 otherwise. | |
164 | */ | |
165 | static int find_old_idx(struct ubifs_info *c, int lnum, int offs) | |
166 | { | |
167 | struct ubifs_old_idx *o; | |
168 | struct rb_node *p; | |
169 | ||
170 | p = c->old_idx.rb_node; | |
171 | while (p) { | |
172 | o = rb_entry(p, struct ubifs_old_idx, rb); | |
173 | if (lnum < o->lnum) | |
174 | p = p->rb_left; | |
175 | else if (lnum > o->lnum) | |
176 | p = p->rb_right; | |
177 | else if (offs < o->offs) | |
178 | p = p->rb_left; | |
179 | else if (offs > o->offs) | |
180 | p = p->rb_right; | |
181 | else | |
182 | return 1; | |
183 | } | |
184 | return 0; | |
185 | } | |
186 | ||
187 | /** | |
188 | * is_idx_node_in_use - determine if an index node can be overwritten. | |
189 | * @c: UBIFS file-system description object | |
190 | * @key: key of index node | |
191 | * @level: index node level | |
192 | * @lnum: LEB number of index node | |
193 | * @offs: offset of index node | |
194 | * | |
195 | * If @key / @lnum / @offs identify an index node that was not part of the old | |
196 | * index, then this function returns %0 (obsolete). Else if the index node was | |
197 | * part of the old index but is now dirty %1 is returned, else if it is clean %2 | |
198 | * is returned. A negative error code is returned on failure. | |
199 | */ | |
200 | static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key, | |
201 | int level, int lnum, int offs) | |
202 | { | |
203 | int ret; | |
204 | ||
205 | ret = is_idx_node_in_tnc(c, key, level, lnum, offs); | |
206 | if (ret < 0) | |
207 | return ret; /* Error code */ | |
208 | if (ret == 0) | |
209 | if (find_old_idx(c, lnum, offs)) | |
210 | return 1; | |
211 | return ret; | |
212 | } | |
213 | ||
214 | /** | |
215 | * layout_leb_in_gaps - layout index nodes using in-the-gaps method. | |
216 | * @c: UBIFS file-system description object | |
217 | * @p: return LEB number here | |
218 | * | |
219 | * This function lays out new index nodes for dirty znodes using in-the-gaps | |
220 | * method of TNC commit. | |
221 | * This function merely puts the next znode into the next gap, making no attempt | |
222 | * to try to maximise the number of znodes that fit. | |
223 | * This function returns the number of index nodes written into the gaps, or a | |
224 | * negative error code on failure. | |
225 | */ | |
226 | static int layout_leb_in_gaps(struct ubifs_info *c, int *p) | |
227 | { | |
228 | struct ubifs_scan_leb *sleb; | |
229 | struct ubifs_scan_node *snod; | |
230 | int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written; | |
231 | ||
232 | tot_written = 0; | |
233 | /* Get an index LEB with lots of obsolete index nodes */ | |
234 | lnum = ubifs_find_dirty_idx_leb(c); | |
235 | if (lnum < 0) | |
236 | /* | |
237 | * There also may be dirt in the index head that could be | |
238 | * filled, however we do not check there at present. | |
239 | */ | |
240 | return lnum; /* Error code */ | |
241 | *p = lnum; | |
242 | dbg_gc("LEB %d", lnum); | |
243 | /* | |
244 | * Scan the index LEB. We use the generic scan for this even though | |
245 | * it is more comprehensive and less efficient than is needed for this | |
246 | * purpose. | |
247 | */ | |
348709ba | 248 | sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0); |
1e51764a AB |
249 | c->ileb_len = 0; |
250 | if (IS_ERR(sleb)) | |
251 | return PTR_ERR(sleb); | |
252 | gap_start = 0; | |
253 | list_for_each_entry(snod, &sleb->nodes, list) { | |
254 | struct ubifs_idx_node *idx; | |
255 | int in_use, level; | |
256 | ||
257 | ubifs_assert(snod->type == UBIFS_IDX_NODE); | |
258 | idx = snod->node; | |
259 | key_read(c, ubifs_idx_key(c, idx), &snod->key); | |
260 | level = le16_to_cpu(idx->level); | |
261 | /* Determine if the index node is in use (not obsolete) */ | |
262 | in_use = is_idx_node_in_use(c, &snod->key, level, lnum, | |
263 | snod->offs); | |
264 | if (in_use < 0) { | |
265 | ubifs_scan_destroy(sleb); | |
266 | return in_use; /* Error code */ | |
267 | } | |
268 | if (in_use) { | |
269 | if (in_use == 1) | |
270 | dirt += ALIGN(snod->len, 8); | |
271 | /* | |
272 | * The obsolete index nodes form gaps that can be | |
273 | * overwritten. This gap has ended because we have | |
274 | * found an index node that is still in use | |
275 | * i.e. not obsolete | |
276 | */ | |
277 | gap_end = snod->offs; | |
278 | /* Try to fill gap */ | |
279 | written = fill_gap(c, lnum, gap_start, gap_end, &dirt); | |
280 | if (written < 0) { | |
281 | ubifs_scan_destroy(sleb); | |
282 | return written; /* Error code */ | |
283 | } | |
284 | tot_written += written; | |
285 | gap_start = ALIGN(snod->offs + snod->len, 8); | |
286 | } | |
287 | } | |
288 | ubifs_scan_destroy(sleb); | |
289 | c->ileb_len = c->leb_size; | |
290 | gap_end = c->leb_size; | |
291 | /* Try to fill gap */ | |
292 | written = fill_gap(c, lnum, gap_start, gap_end, &dirt); | |
293 | if (written < 0) | |
294 | return written; /* Error code */ | |
295 | tot_written += written; | |
296 | if (tot_written == 0) { | |
297 | struct ubifs_lprops lp; | |
298 | ||
299 | dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); | |
300 | err = ubifs_read_one_lp(c, lnum, &lp); | |
301 | if (err) | |
302 | return err; | |
303 | if (lp.free == c->leb_size) { | |
304 | /* | |
305 | * We must have snatched this LEB from the idx_gc list | |
306 | * so we need to correct the free and dirty space. | |
307 | */ | |
308 | err = ubifs_change_one_lp(c, lnum, | |
309 | c->leb_size - c->ileb_len, | |
310 | dirt, 0, 0, 0); | |
311 | if (err) | |
312 | return err; | |
313 | } | |
314 | return 0; | |
315 | } | |
316 | err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt, | |
317 | 0, 0, 0); | |
318 | if (err) | |
319 | return err; | |
320 | err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len, | |
321 | UBI_SHORTTERM); | |
322 | if (err) | |
323 | return err; | |
324 | dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); | |
325 | return tot_written; | |
326 | } | |
327 | ||
328 | /** | |
329 | * get_leb_cnt - calculate the number of empty LEBs needed to commit. | |
330 | * @c: UBIFS file-system description object | |
331 | * @cnt: number of znodes to commit | |
332 | * | |
333 | * This function returns the number of empty LEBs needed to commit @cnt znodes | |
334 | * to the current index head. The number is not exact and may be more than | |
335 | * needed. | |
336 | */ | |
337 | static int get_leb_cnt(struct ubifs_info *c, int cnt) | |
338 | { | |
339 | int d; | |
340 | ||
341 | /* Assume maximum index node size (i.e. overestimate space needed) */ | |
342 | cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz; | |
343 | if (cnt < 0) | |
344 | cnt = 0; | |
345 | d = c->leb_size / c->max_idx_node_sz; | |
346 | return DIV_ROUND_UP(cnt, d); | |
347 | } | |
348 | ||
349 | /** | |
350 | * layout_in_gaps - in-the-gaps method of committing TNC. | |
351 | * @c: UBIFS file-system description object | |
352 | * @cnt: number of dirty znodes to commit. | |
353 | * | |
354 | * This function lays out new index nodes for dirty znodes using in-the-gaps | |
355 | * method of TNC commit. | |
356 | * | |
357 | * This function returns %0 on success and a negative error code on failure. | |
358 | */ | |
359 | static int layout_in_gaps(struct ubifs_info *c, int cnt) | |
360 | { | |
361 | int err, leb_needed_cnt, written, *p; | |
362 | ||
363 | dbg_gc("%d znodes to write", cnt); | |
364 | ||
365 | c->gap_lebs = kmalloc(sizeof(int) * (c->lst.idx_lebs + 1), GFP_NOFS); | |
366 | if (!c->gap_lebs) | |
367 | return -ENOMEM; | |
368 | ||
369 | p = c->gap_lebs; | |
370 | do { | |
371 | ubifs_assert(p < c->gap_lebs + sizeof(int) * c->lst.idx_lebs); | |
372 | written = layout_leb_in_gaps(c, p); | |
373 | if (written < 0) { | |
374 | err = written; | |
0010f18a AB |
375 | if (err != -ENOSPC) { |
376 | kfree(c->gap_lebs); | |
377 | c->gap_lebs = NULL; | |
378 | return err; | |
1e51764a | 379 | } |
0010f18a AB |
380 | if (!dbg_force_in_the_gaps_enabled) { |
381 | /* | |
382 | * Do not print scary warnings if the debugging | |
383 | * option which forces in-the-gaps is enabled. | |
384 | */ | |
385 | ubifs_err("out of space"); | |
386 | spin_lock(&c->space_lock); | |
387 | dbg_dump_budg(c); | |
388 | spin_unlock(&c->space_lock); | |
389 | dbg_dump_lprops(c); | |
390 | } | |
391 | /* Try to commit anyway */ | |
392 | err = 0; | |
393 | break; | |
1e51764a AB |
394 | } |
395 | p++; | |
396 | cnt -= written; | |
397 | leb_needed_cnt = get_leb_cnt(c, cnt); | |
398 | dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt, | |
399 | leb_needed_cnt, c->ileb_cnt); | |
400 | } while (leb_needed_cnt > c->ileb_cnt); | |
401 | ||
402 | *p = -1; | |
403 | return 0; | |
404 | } | |
405 | ||
406 | /** | |
407 | * layout_in_empty_space - layout index nodes in empty space. | |
408 | * @c: UBIFS file-system description object | |
409 | * | |
410 | * This function lays out new index nodes for dirty znodes using empty LEBs. | |
411 | * | |
412 | * This function returns %0 on success and a negative error code on failure. | |
413 | */ | |
414 | static int layout_in_empty_space(struct ubifs_info *c) | |
415 | { | |
416 | struct ubifs_znode *znode, *cnext, *zp; | |
417 | int lnum, offs, len, next_len, buf_len, buf_offs, used, avail; | |
418 | int wlen, blen, err; | |
419 | ||
420 | cnext = c->enext; | |
421 | if (!cnext) | |
422 | return 0; | |
423 | ||
424 | lnum = c->ihead_lnum; | |
425 | buf_offs = c->ihead_offs; | |
426 | ||
427 | buf_len = ubifs_idx_node_sz(c, c->fanout); | |
428 | buf_len = ALIGN(buf_len, c->min_io_size); | |
429 | used = 0; | |
430 | avail = buf_len; | |
431 | ||
432 | /* Ensure there is enough room for first write */ | |
433 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
434 | if (buf_offs + next_len > c->leb_size) | |
435 | lnum = -1; | |
436 | ||
437 | while (1) { | |
438 | znode = cnext; | |
439 | ||
440 | len = ubifs_idx_node_sz(c, znode->child_cnt); | |
441 | ||
442 | /* Determine the index node position */ | |
443 | if (lnum == -1) { | |
444 | if (c->ileb_nxt >= c->ileb_cnt) { | |
445 | ubifs_err("out of space"); | |
446 | return -ENOSPC; | |
447 | } | |
448 | lnum = c->ilebs[c->ileb_nxt++]; | |
449 | buf_offs = 0; | |
450 | used = 0; | |
451 | avail = buf_len; | |
452 | } | |
453 | ||
454 | offs = buf_offs + used; | |
455 | ||
456 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
457 | znode->lnum = lnum; | |
458 | znode->offs = offs; | |
459 | znode->len = len; | |
460 | #endif | |
461 | ||
462 | /* Update the parent */ | |
463 | zp = znode->parent; | |
464 | if (zp) { | |
465 | struct ubifs_zbranch *zbr; | |
466 | int i; | |
467 | ||
468 | i = znode->iip; | |
469 | zbr = &zp->zbranch[i]; | |
470 | zbr->lnum = lnum; | |
471 | zbr->offs = offs; | |
472 | zbr->len = len; | |
473 | } else { | |
474 | c->zroot.lnum = lnum; | |
475 | c->zroot.offs = offs; | |
476 | c->zroot.len = len; | |
477 | } | |
478 | c->calc_idx_sz += ALIGN(len, 8); | |
479 | ||
480 | /* | |
481 | * Once lprops is updated, we can decrease the dirty znode count | |
482 | * but it is easier to just do it here. | |
483 | */ | |
484 | atomic_long_dec(&c->dirty_zn_cnt); | |
485 | ||
486 | /* | |
487 | * Calculate the next index node length to see if there is | |
488 | * enough room for it | |
489 | */ | |
490 | cnext = znode->cnext; | |
491 | if (cnext == c->cnext) | |
492 | next_len = 0; | |
493 | else | |
494 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
495 | ||
496 | if (c->min_io_size == 1) { | |
497 | buf_offs += ALIGN(len, 8); | |
498 | if (next_len) { | |
499 | if (buf_offs + next_len <= c->leb_size) | |
500 | continue; | |
501 | err = ubifs_update_one_lp(c, lnum, 0, | |
502 | c->leb_size - buf_offs, 0, 0); | |
503 | if (err) | |
504 | return err; | |
505 | lnum = -1; | |
506 | continue; | |
507 | } | |
508 | err = ubifs_update_one_lp(c, lnum, | |
509 | c->leb_size - buf_offs, 0, 0, 0); | |
510 | if (err) | |
511 | return err; | |
512 | break; | |
513 | } | |
514 | ||
515 | /* Update buffer positions */ | |
516 | wlen = used + len; | |
517 | used += ALIGN(len, 8); | |
518 | avail -= ALIGN(len, 8); | |
519 | ||
520 | if (next_len != 0 && | |
521 | buf_offs + used + next_len <= c->leb_size && | |
522 | avail > 0) | |
523 | continue; | |
524 | ||
525 | if (avail <= 0 && next_len && | |
526 | buf_offs + used + next_len <= c->leb_size) | |
527 | blen = buf_len; | |
528 | else | |
529 | blen = ALIGN(wlen, c->min_io_size); | |
530 | ||
531 | /* The buffer is full or there are no more znodes to do */ | |
532 | buf_offs += blen; | |
533 | if (next_len) { | |
534 | if (buf_offs + next_len > c->leb_size) { | |
535 | err = ubifs_update_one_lp(c, lnum, | |
536 | c->leb_size - buf_offs, blen - used, | |
537 | 0, 0); | |
538 | if (err) | |
539 | return err; | |
540 | lnum = -1; | |
541 | } | |
542 | used -= blen; | |
543 | if (used < 0) | |
544 | used = 0; | |
545 | avail = buf_len - used; | |
546 | continue; | |
547 | } | |
548 | err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs, | |
549 | blen - used, 0, 0); | |
550 | if (err) | |
551 | return err; | |
552 | break; | |
553 | } | |
554 | ||
555 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
17c2f9f8 AB |
556 | c->dbg->new_ihead_lnum = lnum; |
557 | c->dbg->new_ihead_offs = buf_offs; | |
1e51764a AB |
558 | #endif |
559 | ||
560 | return 0; | |
561 | } | |
562 | ||
563 | /** | |
564 | * layout_commit - determine positions of index nodes to commit. | |
565 | * @c: UBIFS file-system description object | |
566 | * @no_space: indicates that insufficient empty LEBs were allocated | |
567 | * @cnt: number of znodes to commit | |
568 | * | |
569 | * Calculate and update the positions of index nodes to commit. If there were | |
570 | * an insufficient number of empty LEBs allocated, then index nodes are placed | |
571 | * into the gaps created by obsolete index nodes in non-empty index LEBs. For | |
572 | * this purpose, an obsolete index node is one that was not in the index as at | |
573 | * the end of the last commit. To write "in-the-gaps" requires that those index | |
574 | * LEBs are updated atomically in-place. | |
575 | */ | |
576 | static int layout_commit(struct ubifs_info *c, int no_space, int cnt) | |
577 | { | |
578 | int err; | |
579 | ||
580 | if (no_space) { | |
581 | err = layout_in_gaps(c, cnt); | |
582 | if (err) | |
583 | return err; | |
584 | } | |
585 | err = layout_in_empty_space(c); | |
586 | return err; | |
587 | } | |
588 | ||
589 | /** | |
590 | * find_first_dirty - find first dirty znode. | |
591 | * @znode: znode to begin searching from | |
592 | */ | |
593 | static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode) | |
594 | { | |
595 | int i, cont; | |
596 | ||
597 | if (!znode) | |
598 | return NULL; | |
599 | ||
600 | while (1) { | |
601 | if (znode->level == 0) { | |
602 | if (ubifs_zn_dirty(znode)) | |
603 | return znode; | |
604 | return NULL; | |
605 | } | |
606 | cont = 0; | |
607 | for (i = 0; i < znode->child_cnt; i++) { | |
608 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; | |
609 | ||
610 | if (zbr->znode && ubifs_zn_dirty(zbr->znode)) { | |
611 | znode = zbr->znode; | |
612 | cont = 1; | |
613 | break; | |
614 | } | |
615 | } | |
616 | if (!cont) { | |
617 | if (ubifs_zn_dirty(znode)) | |
618 | return znode; | |
619 | return NULL; | |
620 | } | |
621 | } | |
622 | } | |
623 | ||
624 | /** | |
625 | * find_next_dirty - find next dirty znode. | |
626 | * @znode: znode to begin searching from | |
627 | */ | |
628 | static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode) | |
629 | { | |
630 | int n = znode->iip + 1; | |
631 | ||
632 | znode = znode->parent; | |
633 | if (!znode) | |
634 | return NULL; | |
635 | for (; n < znode->child_cnt; n++) { | |
636 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; | |
637 | ||
638 | if (zbr->znode && ubifs_zn_dirty(zbr->znode)) | |
639 | return find_first_dirty(zbr->znode); | |
640 | } | |
641 | return znode; | |
642 | } | |
643 | ||
644 | /** | |
645 | * get_znodes_to_commit - create list of dirty znodes to commit. | |
646 | * @c: UBIFS file-system description object | |
647 | * | |
648 | * This function returns the number of znodes to commit. | |
649 | */ | |
650 | static int get_znodes_to_commit(struct ubifs_info *c) | |
651 | { | |
652 | struct ubifs_znode *znode, *cnext; | |
653 | int cnt = 0; | |
654 | ||
655 | c->cnext = find_first_dirty(c->zroot.znode); | |
656 | znode = c->enext = c->cnext; | |
657 | if (!znode) { | |
658 | dbg_cmt("no znodes to commit"); | |
659 | return 0; | |
660 | } | |
661 | cnt += 1; | |
662 | while (1) { | |
663 | ubifs_assert(!test_bit(COW_ZNODE, &znode->flags)); | |
664 | __set_bit(COW_ZNODE, &znode->flags); | |
665 | znode->alt = 0; | |
666 | cnext = find_next_dirty(znode); | |
667 | if (!cnext) { | |
668 | znode->cnext = c->cnext; | |
669 | break; | |
670 | } | |
671 | znode->cnext = cnext; | |
672 | znode = cnext; | |
673 | cnt += 1; | |
674 | } | |
675 | dbg_cmt("committing %d znodes", cnt); | |
676 | ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt)); | |
677 | return cnt; | |
678 | } | |
679 | ||
680 | /** | |
681 | * alloc_idx_lebs - allocate empty LEBs to be used to commit. | |
682 | * @c: UBIFS file-system description object | |
683 | * @cnt: number of znodes to commit | |
684 | * | |
685 | * This function returns %-ENOSPC if it cannot allocate a sufficient number of | |
686 | * empty LEBs. %0 is returned on success, otherwise a negative error code | |
687 | * is returned. | |
688 | */ | |
689 | static int alloc_idx_lebs(struct ubifs_info *c, int cnt) | |
690 | { | |
691 | int i, leb_cnt, lnum; | |
692 | ||
693 | c->ileb_cnt = 0; | |
694 | c->ileb_nxt = 0; | |
695 | leb_cnt = get_leb_cnt(c, cnt); | |
696 | dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt); | |
697 | if (!leb_cnt) | |
698 | return 0; | |
699 | c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS); | |
700 | if (!c->ilebs) | |
701 | return -ENOMEM; | |
702 | for (i = 0; i < leb_cnt; i++) { | |
703 | lnum = ubifs_find_free_leb_for_idx(c); | |
704 | if (lnum < 0) | |
705 | return lnum; | |
706 | c->ilebs[c->ileb_cnt++] = lnum; | |
707 | dbg_cmt("LEB %d", lnum); | |
708 | } | |
709 | if (dbg_force_in_the_gaps()) | |
710 | return -ENOSPC; | |
711 | return 0; | |
712 | } | |
713 | ||
714 | /** | |
715 | * free_unused_idx_lebs - free unused LEBs that were allocated for the commit. | |
716 | * @c: UBIFS file-system description object | |
717 | * | |
718 | * It is possible that we allocate more empty LEBs for the commit than we need. | |
719 | * This functions frees the surplus. | |
720 | * | |
721 | * This function returns %0 on success and a negative error code on failure. | |
722 | */ | |
723 | static int free_unused_idx_lebs(struct ubifs_info *c) | |
724 | { | |
725 | int i, err = 0, lnum, er; | |
726 | ||
727 | for (i = c->ileb_nxt; i < c->ileb_cnt; i++) { | |
728 | lnum = c->ilebs[i]; | |
729 | dbg_cmt("LEB %d", lnum); | |
730 | er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0, | |
731 | LPROPS_INDEX | LPROPS_TAKEN, 0); | |
732 | if (!err) | |
733 | err = er; | |
734 | } | |
735 | return err; | |
736 | } | |
737 | ||
738 | /** | |
739 | * free_idx_lebs - free unused LEBs after commit end. | |
740 | * @c: UBIFS file-system description object | |
741 | * | |
742 | * This function returns %0 on success and a negative error code on failure. | |
743 | */ | |
744 | static int free_idx_lebs(struct ubifs_info *c) | |
745 | { | |
746 | int err; | |
747 | ||
748 | err = free_unused_idx_lebs(c); | |
749 | kfree(c->ilebs); | |
750 | c->ilebs = NULL; | |
751 | return err; | |
752 | } | |
753 | ||
754 | /** | |
755 | * ubifs_tnc_start_commit - start TNC commit. | |
756 | * @c: UBIFS file-system description object | |
757 | * @zroot: new index root position is returned here | |
758 | * | |
759 | * This function prepares the list of indexing nodes to commit and lays out | |
760 | * their positions on flash. If there is not enough free space it uses the | |
761 | * in-gap commit method. Returns zero in case of success and a negative error | |
762 | * code in case of failure. | |
763 | */ | |
764 | int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot) | |
765 | { | |
766 | int err = 0, cnt; | |
767 | ||
768 | mutex_lock(&c->tnc_mutex); | |
769 | err = dbg_check_tnc(c, 1); | |
770 | if (err) | |
771 | goto out; | |
772 | cnt = get_znodes_to_commit(c); | |
773 | if (cnt != 0) { | |
774 | int no_space = 0; | |
775 | ||
776 | err = alloc_idx_lebs(c, cnt); | |
777 | if (err == -ENOSPC) | |
778 | no_space = 1; | |
779 | else if (err) | |
780 | goto out_free; | |
781 | err = layout_commit(c, no_space, cnt); | |
782 | if (err) | |
783 | goto out_free; | |
784 | ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0); | |
785 | err = free_unused_idx_lebs(c); | |
786 | if (err) | |
787 | goto out; | |
788 | } | |
789 | destroy_old_idx(c); | |
790 | memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch)); | |
791 | ||
792 | err = ubifs_save_dirty_idx_lnums(c); | |
793 | if (err) | |
794 | goto out; | |
795 | ||
796 | spin_lock(&c->space_lock); | |
797 | /* | |
798 | * Although we have not finished committing yet, update size of the | |
799 | * committed index ('c->old_idx_sz') and zero out the index growth | |
800 | * budget. It is OK to do this now, because we've reserved all the | |
801 | * space which is needed to commit the index, and it is save for the | |
802 | * budgeting subsystem to assume the index is already committed, | |
803 | * even though it is not. | |
804 | */ | |
650ed50f | 805 | ubifs_assert(c->min_idx_lebs == ubifs_calc_min_idx_lebs(c)); |
1e51764a AB |
806 | c->old_idx_sz = c->calc_idx_sz; |
807 | c->budg_uncommitted_idx = 0; | |
650ed50f | 808 | c->min_idx_lebs = ubifs_calc_min_idx_lebs(c); |
1e51764a AB |
809 | spin_unlock(&c->space_lock); |
810 | mutex_unlock(&c->tnc_mutex); | |
811 | ||
812 | dbg_cmt("number of index LEBs %d", c->lst.idx_lebs); | |
813 | dbg_cmt("size of index %llu", c->calc_idx_sz); | |
814 | return err; | |
815 | ||
816 | out_free: | |
817 | free_idx_lebs(c); | |
818 | out: | |
819 | mutex_unlock(&c->tnc_mutex); | |
820 | return err; | |
821 | } | |
822 | ||
823 | /** | |
824 | * write_index - write index nodes. | |
825 | * @c: UBIFS file-system description object | |
826 | * | |
827 | * This function writes the index nodes whose positions were laid out in the | |
828 | * layout_in_empty_space function. | |
829 | */ | |
830 | static int write_index(struct ubifs_info *c) | |
831 | { | |
832 | struct ubifs_idx_node *idx; | |
833 | struct ubifs_znode *znode, *cnext; | |
834 | int i, lnum, offs, len, next_len, buf_len, buf_offs, used; | |
835 | int avail, wlen, err, lnum_pos = 0; | |
836 | ||
837 | cnext = c->enext; | |
838 | if (!cnext) | |
839 | return 0; | |
840 | ||
841 | /* | |
842 | * Always write index nodes to the index head so that index nodes and | |
843 | * other types of nodes are never mixed in the same erase block. | |
844 | */ | |
845 | lnum = c->ihead_lnum; | |
846 | buf_offs = c->ihead_offs; | |
847 | ||
848 | /* Allocate commit buffer */ | |
849 | buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size); | |
850 | used = 0; | |
851 | avail = buf_len; | |
852 | ||
853 | /* Ensure there is enough room for first write */ | |
854 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
855 | if (buf_offs + next_len > c->leb_size) { | |
856 | err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0, | |
857 | LPROPS_TAKEN); | |
858 | if (err) | |
859 | return err; | |
860 | lnum = -1; | |
861 | } | |
862 | ||
863 | while (1) { | |
864 | cond_resched(); | |
865 | ||
866 | znode = cnext; | |
867 | idx = c->cbuf + used; | |
868 | ||
869 | /* Make index node */ | |
870 | idx->ch.node_type = UBIFS_IDX_NODE; | |
871 | idx->child_cnt = cpu_to_le16(znode->child_cnt); | |
872 | idx->level = cpu_to_le16(znode->level); | |
873 | for (i = 0; i < znode->child_cnt; i++) { | |
874 | struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); | |
875 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; | |
876 | ||
877 | key_write_idx(c, &zbr->key, &br->key); | |
878 | br->lnum = cpu_to_le32(zbr->lnum); | |
879 | br->offs = cpu_to_le32(zbr->offs); | |
880 | br->len = cpu_to_le32(zbr->len); | |
881 | if (!zbr->lnum || !zbr->len) { | |
882 | ubifs_err("bad ref in znode"); | |
883 | dbg_dump_znode(c, znode); | |
884 | if (zbr->znode) | |
885 | dbg_dump_znode(c, zbr->znode); | |
886 | } | |
887 | } | |
888 | len = ubifs_idx_node_sz(c, znode->child_cnt); | |
889 | ubifs_prepare_node(c, idx, len, 0); | |
890 | ||
891 | /* Determine the index node position */ | |
892 | if (lnum == -1) { | |
893 | lnum = c->ilebs[lnum_pos++]; | |
894 | buf_offs = 0; | |
895 | used = 0; | |
896 | avail = buf_len; | |
897 | } | |
898 | offs = buf_offs + used; | |
899 | ||
900 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
901 | if (lnum != znode->lnum || offs != znode->offs || | |
902 | len != znode->len) { | |
903 | ubifs_err("inconsistent znode posn"); | |
904 | return -EINVAL; | |
905 | } | |
906 | #endif | |
907 | ||
908 | /* Grab some stuff from znode while we still can */ | |
909 | cnext = znode->cnext; | |
910 | ||
911 | ubifs_assert(ubifs_zn_dirty(znode)); | |
912 | ubifs_assert(test_bit(COW_ZNODE, &znode->flags)); | |
913 | ||
914 | /* | |
915 | * It is important that other threads should see %DIRTY_ZNODE | |
916 | * flag cleared before %COW_ZNODE. Specifically, it matters in | |
917 | * the 'dirty_cow_znode()' function. This is the reason for the | |
918 | * first barrier. Also, we want the bit changes to be seen to | |
919 | * other threads ASAP, to avoid unnecesarry copying, which is | |
920 | * the reason for the second barrier. | |
921 | */ | |
922 | clear_bit(DIRTY_ZNODE, &znode->flags); | |
923 | smp_mb__before_clear_bit(); | |
924 | clear_bit(COW_ZNODE, &znode->flags); | |
925 | smp_mb__after_clear_bit(); | |
926 | ||
927 | /* Do not access znode from this point on */ | |
928 | ||
929 | /* Update buffer positions */ | |
930 | wlen = used + len; | |
931 | used += ALIGN(len, 8); | |
932 | avail -= ALIGN(len, 8); | |
933 | ||
934 | /* | |
935 | * Calculate the next index node length to see if there is | |
936 | * enough room for it | |
937 | */ | |
938 | if (cnext == c->cnext) | |
939 | next_len = 0; | |
940 | else | |
941 | next_len = ubifs_idx_node_sz(c, cnext->child_cnt); | |
942 | ||
943 | if (c->min_io_size == 1) { | |
944 | /* | |
945 | * Write the prepared index node immediately if there is | |
946 | * no minimum IO size | |
947 | */ | |
948 | err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, | |
949 | wlen, UBI_SHORTTERM); | |
950 | if (err) | |
951 | return err; | |
952 | buf_offs += ALIGN(wlen, 8); | |
953 | if (next_len) { | |
954 | used = 0; | |
955 | avail = buf_len; | |
956 | if (buf_offs + next_len > c->leb_size) { | |
957 | err = ubifs_update_one_lp(c, lnum, | |
958 | LPROPS_NC, 0, 0, LPROPS_TAKEN); | |
959 | if (err) | |
960 | return err; | |
961 | lnum = -1; | |
962 | } | |
963 | continue; | |
964 | } | |
965 | } else { | |
966 | int blen, nxt_offs = buf_offs + used + next_len; | |
967 | ||
968 | if (next_len && nxt_offs <= c->leb_size) { | |
969 | if (avail > 0) | |
970 | continue; | |
971 | else | |
972 | blen = buf_len; | |
973 | } else { | |
974 | wlen = ALIGN(wlen, 8); | |
975 | blen = ALIGN(wlen, c->min_io_size); | |
976 | ubifs_pad(c, c->cbuf + wlen, blen - wlen); | |
977 | } | |
978 | /* | |
979 | * The buffer is full or there are no more znodes | |
980 | * to do | |
981 | */ | |
982 | err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, | |
983 | blen, UBI_SHORTTERM); | |
984 | if (err) | |
985 | return err; | |
986 | buf_offs += blen; | |
987 | if (next_len) { | |
988 | if (nxt_offs > c->leb_size) { | |
989 | err = ubifs_update_one_lp(c, lnum, | |
990 | LPROPS_NC, 0, 0, LPROPS_TAKEN); | |
991 | if (err) | |
992 | return err; | |
993 | lnum = -1; | |
994 | } | |
995 | used -= blen; | |
996 | if (used < 0) | |
997 | used = 0; | |
998 | avail = buf_len - used; | |
999 | memmove(c->cbuf, c->cbuf + blen, used); | |
1000 | continue; | |
1001 | } | |
1002 | } | |
1003 | break; | |
1004 | } | |
1005 | ||
1006 | #ifdef CONFIG_UBIFS_FS_DEBUG | |
17c2f9f8 AB |
1007 | if (lnum != c->dbg->new_ihead_lnum || |
1008 | buf_offs != c->dbg->new_ihead_offs) { | |
1e51764a AB |
1009 | ubifs_err("inconsistent ihead"); |
1010 | return -EINVAL; | |
1011 | } | |
1012 | #endif | |
1013 | ||
1014 | c->ihead_lnum = lnum; | |
1015 | c->ihead_offs = buf_offs; | |
1016 | ||
1017 | return 0; | |
1018 | } | |
1019 | ||
1020 | /** | |
1021 | * free_obsolete_znodes - free obsolete znodes. | |
1022 | * @c: UBIFS file-system description object | |
1023 | * | |
1024 | * At the end of commit end, obsolete znodes are freed. | |
1025 | */ | |
1026 | static void free_obsolete_znodes(struct ubifs_info *c) | |
1027 | { | |
1028 | struct ubifs_znode *znode, *cnext; | |
1029 | ||
1030 | cnext = c->cnext; | |
1031 | do { | |
1032 | znode = cnext; | |
1033 | cnext = znode->cnext; | |
1034 | if (test_bit(OBSOLETE_ZNODE, &znode->flags)) | |
1035 | kfree(znode); | |
1036 | else { | |
1037 | znode->cnext = NULL; | |
1038 | atomic_long_inc(&c->clean_zn_cnt); | |
1039 | atomic_long_inc(&ubifs_clean_zn_cnt); | |
1040 | } | |
1041 | } while (cnext != c->cnext); | |
1042 | } | |
1043 | ||
1044 | /** | |
1045 | * return_gap_lebs - return LEBs used by the in-gap commit method. | |
1046 | * @c: UBIFS file-system description object | |
1047 | * | |
1048 | * This function clears the "taken" flag for the LEBs which were used by the | |
1049 | * "commit in-the-gaps" method. | |
1050 | */ | |
1051 | static int return_gap_lebs(struct ubifs_info *c) | |
1052 | { | |
1053 | int *p, err; | |
1054 | ||
1055 | if (!c->gap_lebs) | |
1056 | return 0; | |
1057 | ||
1058 | dbg_cmt(""); | |
1059 | for (p = c->gap_lebs; *p != -1; p++) { | |
1060 | err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0, | |
1061 | LPROPS_TAKEN, 0); | |
1062 | if (err) | |
1063 | return err; | |
1064 | } | |
1065 | ||
1066 | kfree(c->gap_lebs); | |
1067 | c->gap_lebs = NULL; | |
1068 | return 0; | |
1069 | } | |
1070 | ||
1071 | /** | |
1072 | * ubifs_tnc_end_commit - update the TNC for commit end. | |
1073 | * @c: UBIFS file-system description object | |
1074 | * | |
1075 | * Write the dirty znodes. | |
1076 | */ | |
1077 | int ubifs_tnc_end_commit(struct ubifs_info *c) | |
1078 | { | |
1079 | int err; | |
1080 | ||
1081 | if (!c->cnext) | |
1082 | return 0; | |
1083 | ||
1084 | err = return_gap_lebs(c); | |
1085 | if (err) | |
1086 | return err; | |
1087 | ||
1088 | err = write_index(c); | |
1089 | if (err) | |
1090 | return err; | |
1091 | ||
1092 | mutex_lock(&c->tnc_mutex); | |
1093 | ||
1094 | dbg_cmt("TNC height is %d", c->zroot.znode->level + 1); | |
1095 | ||
1096 | free_obsolete_znodes(c); | |
1097 | ||
1098 | c->cnext = NULL; | |
1099 | kfree(c->ilebs); | |
1100 | c->ilebs = NULL; | |
1101 | ||
1102 | mutex_unlock(&c->tnc_mutex); | |
1103 | ||
1104 | return 0; | |
1105 | } |