Linux 2.6.32.17
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ubifs / commit.c
blob4775af401167d71471c4e6035f4aa4ce1d5f6200
1 /*
2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
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.
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.
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
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
24 * This file implements functions that manage the running of the commit process.
25 * Each affected module has its own functions to accomplish their part in the
26 * commit and those functions are called here.
28 * The commit is the process whereby all updates to the index and LEB properties
29 * are written out together and the journal becomes empty. This keeps the
30 * file system consistent - at all times the state can be recreated by reading
31 * the index and LEB properties and then replaying the journal.
33 * The commit is split into two parts named "commit start" and "commit end".
34 * During commit start, the commit process has exclusive access to the journal
35 * by holding the commit semaphore down for writing. As few I/O operations as
36 * possible are performed during commit start, instead the nodes that are to be
37 * written are merely identified. During commit end, the commit semaphore is no
38 * longer held and the journal is again in operation, allowing users to continue
39 * to use the file system while the bulk of the commit I/O is performed. The
40 * purpose of this two-step approach is to prevent the commit from causing any
41 * latency blips. Note that in any case, the commit does not prevent lookups
42 * (as permitted by the TNC mutex), or access to VFS data structures e.g. page
43 * cache.
46 #include <linux/freezer.h>
47 #include <linux/kthread.h>
48 #include "ubifs.h"
50 /**
51 * do_commit - commit the journal.
52 * @c: UBIFS file-system description object
54 * This function implements UBIFS commit. It has to be called with commit lock
55 * locked. Returns zero in case of success and a negative error code in case of
56 * failure.
58 static int do_commit(struct ubifs_info *c)
60 int err, new_ltail_lnum, old_ltail_lnum, i;
61 struct ubifs_zbranch zroot;
62 struct ubifs_lp_stats lst;
64 dbg_cmt("start");
65 if (c->ro_media) {
66 err = -EROFS;
67 goto out_up;
70 /* Sync all write buffers (necessary for recovery) */
71 for (i = 0; i < c->jhead_cnt; i++) {
72 err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
73 if (err)
74 goto out_up;
77 c->cmt_no += 1;
78 err = ubifs_gc_start_commit(c);
79 if (err)
80 goto out_up;
81 err = dbg_check_lprops(c);
82 if (err)
83 goto out_up;
84 err = ubifs_log_start_commit(c, &new_ltail_lnum);
85 if (err)
86 goto out_up;
87 err = ubifs_tnc_start_commit(c, &zroot);
88 if (err)
89 goto out_up;
90 err = ubifs_lpt_start_commit(c);
91 if (err)
92 goto out_up;
93 err = ubifs_orphan_start_commit(c);
94 if (err)
95 goto out_up;
97 ubifs_get_lp_stats(c, &lst);
99 up_write(&c->commit_sem);
101 err = ubifs_tnc_end_commit(c);
102 if (err)
103 goto out;
104 err = ubifs_lpt_end_commit(c);
105 if (err)
106 goto out;
107 err = ubifs_orphan_end_commit(c);
108 if (err)
109 goto out;
110 old_ltail_lnum = c->ltail_lnum;
111 err = ubifs_log_end_commit(c, new_ltail_lnum);
112 if (err)
113 goto out;
114 err = dbg_check_old_index(c, &zroot);
115 if (err)
116 goto out;
118 mutex_lock(&c->mst_mutex);
119 c->mst_node->cmt_no = cpu_to_le64(c->cmt_no);
120 c->mst_node->log_lnum = cpu_to_le32(new_ltail_lnum);
121 c->mst_node->root_lnum = cpu_to_le32(zroot.lnum);
122 c->mst_node->root_offs = cpu_to_le32(zroot.offs);
123 c->mst_node->root_len = cpu_to_le32(zroot.len);
124 c->mst_node->ihead_lnum = cpu_to_le32(c->ihead_lnum);
125 c->mst_node->ihead_offs = cpu_to_le32(c->ihead_offs);
126 c->mst_node->index_size = cpu_to_le64(c->old_idx_sz);
127 c->mst_node->lpt_lnum = cpu_to_le32(c->lpt_lnum);
128 c->mst_node->lpt_offs = cpu_to_le32(c->lpt_offs);
129 c->mst_node->nhead_lnum = cpu_to_le32(c->nhead_lnum);
130 c->mst_node->nhead_offs = cpu_to_le32(c->nhead_offs);
131 c->mst_node->ltab_lnum = cpu_to_le32(c->ltab_lnum);
132 c->mst_node->ltab_offs = cpu_to_le32(c->ltab_offs);
133 c->mst_node->lsave_lnum = cpu_to_le32(c->lsave_lnum);
134 c->mst_node->lsave_offs = cpu_to_le32(c->lsave_offs);
135 c->mst_node->lscan_lnum = cpu_to_le32(c->lscan_lnum);
136 c->mst_node->empty_lebs = cpu_to_le32(lst.empty_lebs);
137 c->mst_node->idx_lebs = cpu_to_le32(lst.idx_lebs);
138 c->mst_node->total_free = cpu_to_le64(lst.total_free);
139 c->mst_node->total_dirty = cpu_to_le64(lst.total_dirty);
140 c->mst_node->total_used = cpu_to_le64(lst.total_used);
141 c->mst_node->total_dead = cpu_to_le64(lst.total_dead);
142 c->mst_node->total_dark = cpu_to_le64(lst.total_dark);
143 if (c->no_orphs)
144 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
145 else
146 c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_NO_ORPHS);
147 err = ubifs_write_master(c);
148 mutex_unlock(&c->mst_mutex);
149 if (err)
150 goto out;
152 err = ubifs_log_post_commit(c, old_ltail_lnum);
153 if (err)
154 goto out;
155 err = ubifs_gc_end_commit(c);
156 if (err)
157 goto out;
158 err = ubifs_lpt_post_commit(c);
159 if (err)
160 goto out;
162 spin_lock(&c->cs_lock);
163 c->cmt_state = COMMIT_RESTING;
164 wake_up(&c->cmt_wq);
165 dbg_cmt("commit end");
166 spin_unlock(&c->cs_lock);
168 return 0;
170 out_up:
171 up_write(&c->commit_sem);
172 out:
173 ubifs_err("commit failed, error %d", err);
174 spin_lock(&c->cs_lock);
175 c->cmt_state = COMMIT_BROKEN;
176 wake_up(&c->cmt_wq);
177 spin_unlock(&c->cs_lock);
178 ubifs_ro_mode(c, err);
179 return err;
183 * run_bg_commit - run background commit if it is needed.
184 * @c: UBIFS file-system description object
186 * This function runs background commit if it is needed. Returns zero in case
187 * of success and a negative error code in case of failure.
189 static int run_bg_commit(struct ubifs_info *c)
191 spin_lock(&c->cs_lock);
193 * Run background commit only if background commit was requested or if
194 * commit is required.
196 if (c->cmt_state != COMMIT_BACKGROUND &&
197 c->cmt_state != COMMIT_REQUIRED)
198 goto out;
199 spin_unlock(&c->cs_lock);
201 down_write(&c->commit_sem);
202 spin_lock(&c->cs_lock);
203 if (c->cmt_state == COMMIT_REQUIRED)
204 c->cmt_state = COMMIT_RUNNING_REQUIRED;
205 else if (c->cmt_state == COMMIT_BACKGROUND)
206 c->cmt_state = COMMIT_RUNNING_BACKGROUND;
207 else
208 goto out_cmt_unlock;
209 spin_unlock(&c->cs_lock);
211 return do_commit(c);
213 out_cmt_unlock:
214 up_write(&c->commit_sem);
215 out:
216 spin_unlock(&c->cs_lock);
217 return 0;
221 * ubifs_bg_thread - UBIFS background thread function.
222 * @info: points to the file-system description object
224 * This function implements various file-system background activities:
225 * o when a write-buffer timer expires it synchronizes the appropriate
226 * write-buffer;
227 * o when the journal is about to be full, it starts in-advance commit.
229 * Note, other stuff like background garbage collection may be added here in
230 * future.
232 int ubifs_bg_thread(void *info)
234 int err;
235 struct ubifs_info *c = info;
237 dbg_msg("background thread \"%s\" started, PID %d",
238 c->bgt_name, current->pid);
239 set_freezable();
241 while (1) {
242 if (kthread_should_stop())
243 break;
245 if (try_to_freeze())
246 continue;
248 set_current_state(TASK_INTERRUPTIBLE);
249 /* Check if there is something to do */
250 if (!c->need_bgt) {
252 * Nothing prevents us from going sleep now and
253 * be never woken up and block the task which
254 * could wait in 'kthread_stop()' forever.
256 if (kthread_should_stop())
257 break;
258 schedule();
259 continue;
260 } else
261 __set_current_state(TASK_RUNNING);
263 c->need_bgt = 0;
264 err = ubifs_bg_wbufs_sync(c);
265 if (err)
266 ubifs_ro_mode(c, err);
268 run_bg_commit(c);
269 cond_resched();
272 dbg_msg("background thread \"%s\" stops", c->bgt_name);
273 return 0;
277 * ubifs_commit_required - set commit state to "required".
278 * @c: UBIFS file-system description object
280 * This function is called if a commit is required but cannot be done from the
281 * calling function, so it is just flagged instead.
283 void ubifs_commit_required(struct ubifs_info *c)
285 spin_lock(&c->cs_lock);
286 switch (c->cmt_state) {
287 case COMMIT_RESTING:
288 case COMMIT_BACKGROUND:
289 dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
290 dbg_cstate(COMMIT_REQUIRED));
291 c->cmt_state = COMMIT_REQUIRED;
292 break;
293 case COMMIT_RUNNING_BACKGROUND:
294 dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
295 dbg_cstate(COMMIT_RUNNING_REQUIRED));
296 c->cmt_state = COMMIT_RUNNING_REQUIRED;
297 break;
298 case COMMIT_REQUIRED:
299 case COMMIT_RUNNING_REQUIRED:
300 case COMMIT_BROKEN:
301 break;
303 spin_unlock(&c->cs_lock);
307 * ubifs_request_bg_commit - notify the background thread to do a commit.
308 * @c: UBIFS file-system description object
310 * This function is called if the journal is full enough to make a commit
311 * worthwhile, so background thread is kicked to start it.
313 void ubifs_request_bg_commit(struct ubifs_info *c)
315 spin_lock(&c->cs_lock);
316 if (c->cmt_state == COMMIT_RESTING) {
317 dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
318 dbg_cstate(COMMIT_BACKGROUND));
319 c->cmt_state = COMMIT_BACKGROUND;
320 spin_unlock(&c->cs_lock);
321 ubifs_wake_up_bgt(c);
322 } else
323 spin_unlock(&c->cs_lock);
327 * wait_for_commit - wait for commit.
328 * @c: UBIFS file-system description object
330 * This function sleeps until the commit operation is no longer running.
332 static int wait_for_commit(struct ubifs_info *c)
334 dbg_cmt("pid %d goes sleep", current->pid);
337 * The following sleeps if the condition is false, and will be woken
338 * when the commit ends. It is possible, although very unlikely, that we
339 * will wake up and see the subsequent commit running, rather than the
340 * one we were waiting for, and go back to sleep. However, we will be
341 * woken again, so there is no danger of sleeping forever.
343 wait_event(c->cmt_wq, c->cmt_state != COMMIT_RUNNING_BACKGROUND &&
344 c->cmt_state != COMMIT_RUNNING_REQUIRED);
345 dbg_cmt("commit finished, pid %d woke up", current->pid);
346 return 0;
350 * ubifs_run_commit - run or wait for commit.
351 * @c: UBIFS file-system description object
353 * This function runs commit and returns zero in case of success and a negative
354 * error code in case of failure.
356 int ubifs_run_commit(struct ubifs_info *c)
358 int err = 0;
360 spin_lock(&c->cs_lock);
361 if (c->cmt_state == COMMIT_BROKEN) {
362 err = -EINVAL;
363 goto out;
366 if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
368 * We set the commit state to 'running required' to indicate
369 * that we want it to complete as quickly as possible.
371 c->cmt_state = COMMIT_RUNNING_REQUIRED;
373 if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
374 spin_unlock(&c->cs_lock);
375 return wait_for_commit(c);
377 spin_unlock(&c->cs_lock);
379 /* Ok, the commit is indeed needed */
381 down_write(&c->commit_sem);
382 spin_lock(&c->cs_lock);
384 * Since we unlocked 'c->cs_lock', the state may have changed, so
385 * re-check it.
387 if (c->cmt_state == COMMIT_BROKEN) {
388 err = -EINVAL;
389 goto out_cmt_unlock;
392 if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
393 c->cmt_state = COMMIT_RUNNING_REQUIRED;
395 if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
396 up_write(&c->commit_sem);
397 spin_unlock(&c->cs_lock);
398 return wait_for_commit(c);
400 c->cmt_state = COMMIT_RUNNING_REQUIRED;
401 spin_unlock(&c->cs_lock);
403 err = do_commit(c);
404 return err;
406 out_cmt_unlock:
407 up_write(&c->commit_sem);
408 out:
409 spin_unlock(&c->cs_lock);
410 return err;
414 * ubifs_gc_should_commit - determine if it is time for GC to run commit.
415 * @c: UBIFS file-system description object
417 * This function is called by garbage collection to determine if commit should
418 * be run. If commit state is @COMMIT_BACKGROUND, which means that the journal
419 * is full enough to start commit, this function returns true. It is not
420 * absolutely necessary to commit yet, but it feels like this should be better
421 * then to keep doing GC. This function returns %1 if GC has to initiate commit
422 * and %0 if not.
424 int ubifs_gc_should_commit(struct ubifs_info *c)
426 int ret = 0;
428 spin_lock(&c->cs_lock);
429 if (c->cmt_state == COMMIT_BACKGROUND) {
430 dbg_cmt("commit required now");
431 c->cmt_state = COMMIT_REQUIRED;
432 } else
433 dbg_cmt("commit not requested");
434 if (c->cmt_state == COMMIT_REQUIRED)
435 ret = 1;
436 spin_unlock(&c->cs_lock);
437 return ret;
440 #ifdef CONFIG_UBIFS_FS_DEBUG
443 * struct idx_node - hold index nodes during index tree traversal.
444 * @list: list
445 * @iip: index in parent (slot number of this indexing node in the parent
446 * indexing node)
447 * @upper_key: all keys in this indexing node have to be less or equivalent to
448 * this key
449 * @idx: index node (8-byte aligned because all node structures must be 8-byte
450 * aligned)
452 struct idx_node {
453 struct list_head list;
454 int iip;
455 union ubifs_key upper_key;
456 struct ubifs_idx_node idx __attribute__((aligned(8)));
460 * dbg_old_index_check_init - get information for the next old index check.
461 * @c: UBIFS file-system description object
462 * @zroot: root of the index
464 * This function records information about the index that will be needed for the
465 * next old index check i.e. 'dbg_check_old_index()'.
467 * This function returns %0 on success and a negative error code on failure.
469 int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot)
471 struct ubifs_idx_node *idx;
472 int lnum, offs, len, err = 0;
473 struct ubifs_debug_info *d = c->dbg;
475 d->old_zroot = *zroot;
476 lnum = d->old_zroot.lnum;
477 offs = d->old_zroot.offs;
478 len = d->old_zroot.len;
480 idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
481 if (!idx)
482 return -ENOMEM;
484 err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
485 if (err)
486 goto out;
488 d->old_zroot_level = le16_to_cpu(idx->level);
489 d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);
490 out:
491 kfree(idx);
492 return err;
496 * dbg_check_old_index - check the old copy of the index.
497 * @c: UBIFS file-system description object
498 * @zroot: root of the new index
500 * In order to be able to recover from an unclean unmount, a complete copy of
501 * the index must exist on flash. This is the "old" index. The commit process
502 * must write the "new" index to flash without overwriting or destroying any
503 * part of the old index. This function is run at commit end in order to check
504 * that the old index does indeed exist completely intact.
506 * This function returns %0 on success and a negative error code on failure.
508 int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
510 int lnum, offs, len, err = 0, uninitialized_var(last_level), child_cnt;
511 int first = 1, iip;
512 struct ubifs_debug_info *d = c->dbg;
513 union ubifs_key uninitialized_var(lower_key), upper_key, l_key, u_key;
514 unsigned long long uninitialized_var(last_sqnum);
515 struct ubifs_idx_node *idx;
516 struct list_head list;
517 struct idx_node *i;
518 size_t sz;
520 if (!(ubifs_chk_flags & UBIFS_CHK_OLD_IDX))
521 goto out;
523 INIT_LIST_HEAD(&list);
525 sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) -
526 UBIFS_IDX_NODE_SZ;
528 /* Start at the old zroot */
529 lnum = d->old_zroot.lnum;
530 offs = d->old_zroot.offs;
531 len = d->old_zroot.len;
532 iip = 0;
535 * Traverse the index tree preorder depth-first i.e. do a node and then
536 * its subtrees from left to right.
538 while (1) {
539 struct ubifs_branch *br;
541 /* Get the next index node */
542 i = kmalloc(sz, GFP_NOFS);
543 if (!i) {
544 err = -ENOMEM;
545 goto out_free;
547 i->iip = iip;
548 /* Keep the index nodes on our path in a linked list */
549 list_add_tail(&i->list, &list);
550 /* Read the index node */
551 idx = &i->idx;
552 err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
553 if (err)
554 goto out_free;
555 /* Validate index node */
556 child_cnt = le16_to_cpu(idx->child_cnt);
557 if (child_cnt < 1 || child_cnt > c->fanout) {
558 err = 1;
559 goto out_dump;
561 if (first) {
562 first = 0;
563 /* Check root level and sqnum */
564 if (le16_to_cpu(idx->level) != d->old_zroot_level) {
565 err = 2;
566 goto out_dump;
568 if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {
569 err = 3;
570 goto out_dump;
572 /* Set last values as though root had a parent */
573 last_level = le16_to_cpu(idx->level) + 1;
574 last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1;
575 key_read(c, ubifs_idx_key(c, idx), &lower_key);
576 highest_ino_key(c, &upper_key, INUM_WATERMARK);
578 key_copy(c, &upper_key, &i->upper_key);
579 if (le16_to_cpu(idx->level) != last_level - 1) {
580 err = 3;
581 goto out_dump;
584 * The index is always written bottom up hence a child's sqnum
585 * is always less than the parents.
587 if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) {
588 err = 4;
589 goto out_dump;
591 /* Check key range */
592 key_read(c, ubifs_idx_key(c, idx), &l_key);
593 br = ubifs_idx_branch(c, idx, child_cnt - 1);
594 key_read(c, &br->key, &u_key);
595 if (keys_cmp(c, &lower_key, &l_key) > 0) {
596 err = 5;
597 goto out_dump;
599 if (keys_cmp(c, &upper_key, &u_key) < 0) {
600 err = 6;
601 goto out_dump;
603 if (keys_cmp(c, &upper_key, &u_key) == 0)
604 if (!is_hash_key(c, &u_key)) {
605 err = 7;
606 goto out_dump;
608 /* Go to next index node */
609 if (le16_to_cpu(idx->level) == 0) {
610 /* At the bottom, so go up until can go right */
611 while (1) {
612 /* Drop the bottom of the list */
613 list_del(&i->list);
614 kfree(i);
615 /* No more list means we are done */
616 if (list_empty(&list))
617 goto out;
618 /* Look at the new bottom */
619 i = list_entry(list.prev, struct idx_node,
620 list);
621 idx = &i->idx;
622 /* Can we go right */
623 if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
624 iip = iip + 1;
625 break;
626 } else
627 /* Nope, so go up again */
628 iip = i->iip;
630 } else
631 /* Go down left */
632 iip = 0;
634 * We have the parent in 'idx' and now we set up for reading the
635 * child pointed to by slot 'iip'.
637 last_level = le16_to_cpu(idx->level);
638 last_sqnum = le64_to_cpu(idx->ch.sqnum);
639 br = ubifs_idx_branch(c, idx, iip);
640 lnum = le32_to_cpu(br->lnum);
641 offs = le32_to_cpu(br->offs);
642 len = le32_to_cpu(br->len);
643 key_read(c, &br->key, &lower_key);
644 if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
645 br = ubifs_idx_branch(c, idx, iip + 1);
646 key_read(c, &br->key, &upper_key);
647 } else
648 key_copy(c, &i->upper_key, &upper_key);
650 out:
651 err = dbg_old_index_check_init(c, zroot);
652 if (err)
653 goto out_free;
655 return 0;
657 out_dump:
658 dbg_err("dumping index node (iip=%d)", i->iip);
659 dbg_dump_node(c, idx);
660 list_del(&i->list);
661 kfree(i);
662 if (!list_empty(&list)) {
663 i = list_entry(list.prev, struct idx_node, list);
664 dbg_err("dumping parent index node");
665 dbg_dump_node(c, &i->idx);
667 out_free:
668 while (!list_empty(&list)) {
669 i = list_entry(list.next, struct idx_node, list);
670 list_del(&i->list);
671 kfree(i);
673 ubifs_err("failed, error %d", err);
674 if (err > 0)
675 err = -EINVAL;
676 return err;
679 #endif /* CONFIG_UBIFS_FS_DEBUG */