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1da177e4 LT |
1 | /* |
2 | * linux/fs/journal.c | |
3 | * | |
4 | * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 | |
5 | * | |
6 | * Copyright 1998 Red Hat corp --- All Rights Reserved | |
7 | * | |
8 | * This file is part of the Linux kernel and is made available under | |
9 | * the terms of the GNU General Public License, version 2, or at your | |
10 | * option, any later version, incorporated herein by reference. | |
11 | * | |
12 | * Generic filesystem journal-writing code; part of the ext2fs | |
13 | * journaling system. | |
14 | * | |
15 | * This file manages journals: areas of disk reserved for logging | |
16 | * transactional updates. This includes the kernel journaling thread | |
17 | * which is responsible for scheduling updates to the log. | |
18 | * | |
19 | * We do not actually manage the physical storage of the journal in this | |
20 | * file: that is left to a per-journal policy function, which allows us | |
21 | * to store the journal within a filesystem-specified area for ext2 | |
22 | * journaling (ext2 can use a reserved inode for storing the log). | |
23 | */ | |
24 | ||
25 | #include <linux/module.h> | |
26 | #include <linux/time.h> | |
27 | #include <linux/fs.h> | |
28 | #include <linux/jbd.h> | |
29 | #include <linux/errno.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/smp_lock.h> | |
32 | #include <linux/init.h> | |
33 | #include <linux/mm.h> | |
34 | #include <linux/suspend.h> | |
35 | #include <linux/pagemap.h> | |
36 | #include <asm/uaccess.h> | |
37 | #include <asm/page.h> | |
38 | #include <linux/proc_fs.h> | |
39 | ||
40 | EXPORT_SYMBOL(journal_start); | |
41 | EXPORT_SYMBOL(journal_restart); | |
42 | EXPORT_SYMBOL(journal_extend); | |
43 | EXPORT_SYMBOL(journal_stop); | |
44 | EXPORT_SYMBOL(journal_lock_updates); | |
45 | EXPORT_SYMBOL(journal_unlock_updates); | |
46 | EXPORT_SYMBOL(journal_get_write_access); | |
47 | EXPORT_SYMBOL(journal_get_create_access); | |
48 | EXPORT_SYMBOL(journal_get_undo_access); | |
49 | EXPORT_SYMBOL(journal_dirty_data); | |
50 | EXPORT_SYMBOL(journal_dirty_metadata); | |
51 | EXPORT_SYMBOL(journal_release_buffer); | |
52 | EXPORT_SYMBOL(journal_forget); | |
53 | #if 0 | |
54 | EXPORT_SYMBOL(journal_sync_buffer); | |
55 | #endif | |
56 | EXPORT_SYMBOL(journal_flush); | |
57 | EXPORT_SYMBOL(journal_revoke); | |
58 | ||
59 | EXPORT_SYMBOL(journal_init_dev); | |
60 | EXPORT_SYMBOL(journal_init_inode); | |
61 | EXPORT_SYMBOL(journal_update_format); | |
62 | EXPORT_SYMBOL(journal_check_used_features); | |
63 | EXPORT_SYMBOL(journal_check_available_features); | |
64 | EXPORT_SYMBOL(journal_set_features); | |
65 | EXPORT_SYMBOL(journal_create); | |
66 | EXPORT_SYMBOL(journal_load); | |
67 | EXPORT_SYMBOL(journal_destroy); | |
68 | EXPORT_SYMBOL(journal_recover); | |
69 | EXPORT_SYMBOL(journal_update_superblock); | |
70 | EXPORT_SYMBOL(journal_abort); | |
71 | EXPORT_SYMBOL(journal_errno); | |
72 | EXPORT_SYMBOL(journal_ack_err); | |
73 | EXPORT_SYMBOL(journal_clear_err); | |
74 | EXPORT_SYMBOL(log_wait_commit); | |
75 | EXPORT_SYMBOL(journal_start_commit); | |
76 | EXPORT_SYMBOL(journal_force_commit_nested); | |
77 | EXPORT_SYMBOL(journal_wipe); | |
78 | EXPORT_SYMBOL(journal_blocks_per_page); | |
79 | EXPORT_SYMBOL(journal_invalidatepage); | |
80 | EXPORT_SYMBOL(journal_try_to_free_buffers); | |
81 | EXPORT_SYMBOL(journal_force_commit); | |
82 | ||
83 | static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *); | |
84 | ||
85 | /* | |
86 | * Helper function used to manage commit timeouts | |
87 | */ | |
88 | ||
89 | static void commit_timeout(unsigned long __data) | |
90 | { | |
91 | struct task_struct * p = (struct task_struct *) __data; | |
92 | ||
93 | wake_up_process(p); | |
94 | } | |
95 | ||
96 | /* Static check for data structure consistency. There's no code | |
97 | * invoked --- we'll just get a linker failure if things aren't right. | |
98 | */ | |
99 | void __journal_internal_check(void) | |
100 | { | |
101 | extern void journal_bad_superblock_size(void); | |
102 | if (sizeof(struct journal_superblock_s) != 1024) | |
103 | journal_bad_superblock_size(); | |
104 | } | |
105 | ||
106 | /* | |
107 | * kjournald: The main thread function used to manage a logging device | |
108 | * journal. | |
109 | * | |
110 | * This kernel thread is responsible for two things: | |
111 | * | |
112 | * 1) COMMIT: Every so often we need to commit the current state of the | |
113 | * filesystem to disk. The journal thread is responsible for writing | |
114 | * all of the metadata buffers to disk. | |
115 | * | |
116 | * 2) CHECKPOINT: We cannot reuse a used section of the log file until all | |
117 | * of the data in that part of the log has been rewritten elsewhere on | |
118 | * the disk. Flushing these old buffers to reclaim space in the log is | |
119 | * known as checkpointing, and this thread is responsible for that job. | |
120 | */ | |
121 | ||
122 | journal_t *current_journal; // AKPM: debug | |
123 | ||
124 | int kjournald(void *arg) | |
125 | { | |
126 | journal_t *journal = (journal_t *) arg; | |
127 | transaction_t *transaction; | |
128 | struct timer_list timer; | |
129 | ||
130 | current_journal = journal; | |
131 | ||
132 | daemonize("kjournald"); | |
133 | ||
134 | /* Set up an interval timer which can be used to trigger a | |
135 | commit wakeup after the commit interval expires */ | |
136 | init_timer(&timer); | |
137 | timer.data = (unsigned long) current; | |
138 | timer.function = commit_timeout; | |
139 | journal->j_commit_timer = &timer; | |
140 | ||
141 | /* Record that the journal thread is running */ | |
142 | journal->j_task = current; | |
143 | wake_up(&journal->j_wait_done_commit); | |
144 | ||
145 | printk(KERN_INFO "kjournald starting. Commit interval %ld seconds\n", | |
146 | journal->j_commit_interval / HZ); | |
147 | ||
148 | /* | |
149 | * And now, wait forever for commit wakeup events. | |
150 | */ | |
151 | spin_lock(&journal->j_state_lock); | |
152 | ||
153 | loop: | |
154 | if (journal->j_flags & JFS_UNMOUNT) | |
155 | goto end_loop; | |
156 | ||
157 | jbd_debug(1, "commit_sequence=%d, commit_request=%d\n", | |
158 | journal->j_commit_sequence, journal->j_commit_request); | |
159 | ||
160 | if (journal->j_commit_sequence != journal->j_commit_request) { | |
161 | jbd_debug(1, "OK, requests differ\n"); | |
162 | spin_unlock(&journal->j_state_lock); | |
163 | del_timer_sync(journal->j_commit_timer); | |
164 | journal_commit_transaction(journal); | |
165 | spin_lock(&journal->j_state_lock); | |
166 | goto loop; | |
167 | } | |
168 | ||
169 | wake_up(&journal->j_wait_done_commit); | |
170 | if (current->flags & PF_FREEZE) { | |
171 | /* | |
172 | * The simpler the better. Flushing journal isn't a | |
173 | * good idea, because that depends on threads that may | |
174 | * be already stopped. | |
175 | */ | |
176 | jbd_debug(1, "Now suspending kjournald\n"); | |
177 | spin_unlock(&journal->j_state_lock); | |
178 | refrigerator(PF_FREEZE); | |
179 | spin_lock(&journal->j_state_lock); | |
180 | } else { | |
181 | /* | |
182 | * We assume on resume that commits are already there, | |
183 | * so we don't sleep | |
184 | */ | |
185 | DEFINE_WAIT(wait); | |
186 | int should_sleep = 1; | |
187 | ||
188 | prepare_to_wait(&journal->j_wait_commit, &wait, | |
189 | TASK_INTERRUPTIBLE); | |
190 | if (journal->j_commit_sequence != journal->j_commit_request) | |
191 | should_sleep = 0; | |
192 | transaction = journal->j_running_transaction; | |
193 | if (transaction && time_after_eq(jiffies, | |
194 | transaction->t_expires)) | |
195 | should_sleep = 0; | |
196 | if (should_sleep) { | |
197 | spin_unlock(&journal->j_state_lock); | |
198 | schedule(); | |
199 | spin_lock(&journal->j_state_lock); | |
200 | } | |
201 | finish_wait(&journal->j_wait_commit, &wait); | |
202 | } | |
203 | ||
204 | jbd_debug(1, "kjournald wakes\n"); | |
205 | ||
206 | /* | |
207 | * Were we woken up by a commit wakeup event? | |
208 | */ | |
209 | transaction = journal->j_running_transaction; | |
210 | if (transaction && time_after_eq(jiffies, transaction->t_expires)) { | |
211 | journal->j_commit_request = transaction->t_tid; | |
212 | jbd_debug(1, "woke because of timeout\n"); | |
213 | } | |
214 | goto loop; | |
215 | ||
216 | end_loop: | |
217 | spin_unlock(&journal->j_state_lock); | |
218 | del_timer_sync(journal->j_commit_timer); | |
219 | journal->j_task = NULL; | |
220 | wake_up(&journal->j_wait_done_commit); | |
221 | jbd_debug(1, "Journal thread exiting.\n"); | |
222 | return 0; | |
223 | } | |
224 | ||
225 | static void journal_start_thread(journal_t *journal) | |
226 | { | |
227 | kernel_thread(kjournald, journal, CLONE_VM|CLONE_FS|CLONE_FILES); | |
228 | wait_event(journal->j_wait_done_commit, journal->j_task != 0); | |
229 | } | |
230 | ||
231 | static void journal_kill_thread(journal_t *journal) | |
232 | { | |
233 | spin_lock(&journal->j_state_lock); | |
234 | journal->j_flags |= JFS_UNMOUNT; | |
235 | ||
236 | while (journal->j_task) { | |
237 | wake_up(&journal->j_wait_commit); | |
238 | spin_unlock(&journal->j_state_lock); | |
239 | wait_event(journal->j_wait_done_commit, journal->j_task == 0); | |
240 | spin_lock(&journal->j_state_lock); | |
241 | } | |
242 | spin_unlock(&journal->j_state_lock); | |
243 | } | |
244 | ||
245 | /* | |
246 | * journal_write_metadata_buffer: write a metadata buffer to the journal. | |
247 | * | |
248 | * Writes a metadata buffer to a given disk block. The actual IO is not | |
249 | * performed but a new buffer_head is constructed which labels the data | |
250 | * to be written with the correct destination disk block. | |
251 | * | |
252 | * Any magic-number escaping which needs to be done will cause a | |
253 | * copy-out here. If the buffer happens to start with the | |
254 | * JFS_MAGIC_NUMBER, then we can't write it to the log directly: the | |
255 | * magic number is only written to the log for descripter blocks. In | |
256 | * this case, we copy the data and replace the first word with 0, and we | |
257 | * return a result code which indicates that this buffer needs to be | |
258 | * marked as an escaped buffer in the corresponding log descriptor | |
259 | * block. The missing word can then be restored when the block is read | |
260 | * during recovery. | |
261 | * | |
262 | * If the source buffer has already been modified by a new transaction | |
263 | * since we took the last commit snapshot, we use the frozen copy of | |
264 | * that data for IO. If we end up using the existing buffer_head's data | |
265 | * for the write, then we *have* to lock the buffer to prevent anyone | |
266 | * else from using and possibly modifying it while the IO is in | |
267 | * progress. | |
268 | * | |
269 | * The function returns a pointer to the buffer_heads to be used for IO. | |
270 | * | |
271 | * We assume that the journal has already been locked in this function. | |
272 | * | |
273 | * Return value: | |
274 | * <0: Error | |
275 | * >=0: Finished OK | |
276 | * | |
277 | * On success: | |
278 | * Bit 0 set == escape performed on the data | |
279 | * Bit 1 set == buffer copy-out performed (kfree the data after IO) | |
280 | */ | |
281 | ||
282 | int journal_write_metadata_buffer(transaction_t *transaction, | |
283 | struct journal_head *jh_in, | |
284 | struct journal_head **jh_out, | |
285 | int blocknr) | |
286 | { | |
287 | int need_copy_out = 0; | |
288 | int done_copy_out = 0; | |
289 | int do_escape = 0; | |
290 | char *mapped_data; | |
291 | struct buffer_head *new_bh; | |
292 | struct journal_head *new_jh; | |
293 | struct page *new_page; | |
294 | unsigned int new_offset; | |
295 | struct buffer_head *bh_in = jh2bh(jh_in); | |
296 | ||
297 | /* | |
298 | * The buffer really shouldn't be locked: only the current committing | |
299 | * transaction is allowed to write it, so nobody else is allowed | |
300 | * to do any IO. | |
301 | * | |
302 | * akpm: except if we're journalling data, and write() output is | |
303 | * also part of a shared mapping, and another thread has | |
304 | * decided to launch a writepage() against this buffer. | |
305 | */ | |
306 | J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in)); | |
307 | ||
308 | new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL); | |
309 | ||
310 | /* | |
311 | * If a new transaction has already done a buffer copy-out, then | |
312 | * we use that version of the data for the commit. | |
313 | */ | |
314 | jbd_lock_bh_state(bh_in); | |
315 | repeat: | |
316 | if (jh_in->b_frozen_data) { | |
317 | done_copy_out = 1; | |
318 | new_page = virt_to_page(jh_in->b_frozen_data); | |
319 | new_offset = offset_in_page(jh_in->b_frozen_data); | |
320 | } else { | |
321 | new_page = jh2bh(jh_in)->b_page; | |
322 | new_offset = offset_in_page(jh2bh(jh_in)->b_data); | |
323 | } | |
324 | ||
325 | mapped_data = kmap_atomic(new_page, KM_USER0); | |
326 | /* | |
327 | * Check for escaping | |
328 | */ | |
329 | if (*((__be32 *)(mapped_data + new_offset)) == | |
330 | cpu_to_be32(JFS_MAGIC_NUMBER)) { | |
331 | need_copy_out = 1; | |
332 | do_escape = 1; | |
333 | } | |
334 | kunmap_atomic(mapped_data, KM_USER0); | |
335 | ||
336 | /* | |
337 | * Do we need to do a data copy? | |
338 | */ | |
339 | if (need_copy_out && !done_copy_out) { | |
340 | char *tmp; | |
341 | ||
342 | jbd_unlock_bh_state(bh_in); | |
343 | tmp = jbd_rep_kmalloc(bh_in->b_size, GFP_NOFS); | |
344 | jbd_lock_bh_state(bh_in); | |
345 | if (jh_in->b_frozen_data) { | |
346 | kfree(tmp); | |
347 | goto repeat; | |
348 | } | |
349 | ||
350 | jh_in->b_frozen_data = tmp; | |
351 | mapped_data = kmap_atomic(new_page, KM_USER0); | |
352 | memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size); | |
353 | kunmap_atomic(mapped_data, KM_USER0); | |
354 | ||
355 | new_page = virt_to_page(tmp); | |
356 | new_offset = offset_in_page(tmp); | |
357 | done_copy_out = 1; | |
358 | } | |
359 | ||
360 | /* | |
361 | * Did we need to do an escaping? Now we've done all the | |
362 | * copying, we can finally do so. | |
363 | */ | |
364 | if (do_escape) { | |
365 | mapped_data = kmap_atomic(new_page, KM_USER0); | |
366 | *((unsigned int *)(mapped_data + new_offset)) = 0; | |
367 | kunmap_atomic(mapped_data, KM_USER0); | |
368 | } | |
369 | ||
370 | /* keep subsequent assertions sane */ | |
371 | new_bh->b_state = 0; | |
372 | init_buffer(new_bh, NULL, NULL); | |
373 | atomic_set(&new_bh->b_count, 1); | |
374 | jbd_unlock_bh_state(bh_in); | |
375 | ||
376 | new_jh = journal_add_journal_head(new_bh); /* This sleeps */ | |
377 | ||
378 | set_bh_page(new_bh, new_page, new_offset); | |
379 | new_jh->b_transaction = NULL; | |
380 | new_bh->b_size = jh2bh(jh_in)->b_size; | |
381 | new_bh->b_bdev = transaction->t_journal->j_dev; | |
382 | new_bh->b_blocknr = blocknr; | |
383 | set_buffer_mapped(new_bh); | |
384 | set_buffer_dirty(new_bh); | |
385 | ||
386 | *jh_out = new_jh; | |
387 | ||
388 | /* | |
389 | * The to-be-written buffer needs to get moved to the io queue, | |
390 | * and the original buffer whose contents we are shadowing or | |
391 | * copying is moved to the transaction's shadow queue. | |
392 | */ | |
393 | JBUFFER_TRACE(jh_in, "file as BJ_Shadow"); | |
394 | journal_file_buffer(jh_in, transaction, BJ_Shadow); | |
395 | JBUFFER_TRACE(new_jh, "file as BJ_IO"); | |
396 | journal_file_buffer(new_jh, transaction, BJ_IO); | |
397 | ||
398 | return do_escape | (done_copy_out << 1); | |
399 | } | |
400 | ||
401 | /* | |
402 | * Allocation code for the journal file. Manage the space left in the | |
403 | * journal, so that we can begin checkpointing when appropriate. | |
404 | */ | |
405 | ||
406 | /* | |
407 | * __log_space_left: Return the number of free blocks left in the journal. | |
408 | * | |
409 | * Called with the journal already locked. | |
410 | * | |
411 | * Called under j_state_lock | |
412 | */ | |
413 | ||
414 | int __log_space_left(journal_t *journal) | |
415 | { | |
416 | int left = journal->j_free; | |
417 | ||
418 | assert_spin_locked(&journal->j_state_lock); | |
419 | ||
420 | /* | |
421 | * Be pessimistic here about the number of those free blocks which | |
422 | * might be required for log descriptor control blocks. | |
423 | */ | |
424 | ||
425 | #define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */ | |
426 | ||
427 | left -= MIN_LOG_RESERVED_BLOCKS; | |
428 | ||
429 | if (left <= 0) | |
430 | return 0; | |
431 | left -= (left >> 3); | |
432 | return left; | |
433 | } | |
434 | ||
435 | /* | |
436 | * Called under j_state_lock. Returns true if a transaction was started. | |
437 | */ | |
438 | int __log_start_commit(journal_t *journal, tid_t target) | |
439 | { | |
440 | /* | |
441 | * Are we already doing a recent enough commit? | |
442 | */ | |
443 | if (!tid_geq(journal->j_commit_request, target)) { | |
444 | /* | |
445 | * We want a new commit: OK, mark the request and wakup the | |
446 | * commit thread. We do _not_ do the commit ourselves. | |
447 | */ | |
448 | ||
449 | journal->j_commit_request = target; | |
450 | jbd_debug(1, "JBD: requesting commit %d/%d\n", | |
451 | journal->j_commit_request, | |
452 | journal->j_commit_sequence); | |
453 | wake_up(&journal->j_wait_commit); | |
454 | return 1; | |
455 | } | |
456 | return 0; | |
457 | } | |
458 | ||
459 | int log_start_commit(journal_t *journal, tid_t tid) | |
460 | { | |
461 | int ret; | |
462 | ||
463 | spin_lock(&journal->j_state_lock); | |
464 | ret = __log_start_commit(journal, tid); | |
465 | spin_unlock(&journal->j_state_lock); | |
466 | return ret; | |
467 | } | |
468 | ||
469 | /* | |
470 | * Force and wait upon a commit if the calling process is not within | |
471 | * transaction. This is used for forcing out undo-protected data which contains | |
472 | * bitmaps, when the fs is running out of space. | |
473 | * | |
474 | * We can only force the running transaction if we don't have an active handle; | |
475 | * otherwise, we will deadlock. | |
476 | * | |
477 | * Returns true if a transaction was started. | |
478 | */ | |
479 | int journal_force_commit_nested(journal_t *journal) | |
480 | { | |
481 | transaction_t *transaction = NULL; | |
482 | tid_t tid; | |
483 | ||
484 | spin_lock(&journal->j_state_lock); | |
485 | if (journal->j_running_transaction && !current->journal_info) { | |
486 | transaction = journal->j_running_transaction; | |
487 | __log_start_commit(journal, transaction->t_tid); | |
488 | } else if (journal->j_committing_transaction) | |
489 | transaction = journal->j_committing_transaction; | |
490 | ||
491 | if (!transaction) { | |
492 | spin_unlock(&journal->j_state_lock); | |
493 | return 0; /* Nothing to retry */ | |
494 | } | |
495 | ||
496 | tid = transaction->t_tid; | |
497 | spin_unlock(&journal->j_state_lock); | |
498 | log_wait_commit(journal, tid); | |
499 | return 1; | |
500 | } | |
501 | ||
502 | /* | |
503 | * Start a commit of the current running transaction (if any). Returns true | |
504 | * if a transaction was started, and fills its tid in at *ptid | |
505 | */ | |
506 | int journal_start_commit(journal_t *journal, tid_t *ptid) | |
507 | { | |
508 | int ret = 0; | |
509 | ||
510 | spin_lock(&journal->j_state_lock); | |
511 | if (journal->j_running_transaction) { | |
512 | tid_t tid = journal->j_running_transaction->t_tid; | |
513 | ||
514 | ret = __log_start_commit(journal, tid); | |
515 | if (ret && ptid) | |
516 | *ptid = tid; | |
517 | } else if (journal->j_committing_transaction && ptid) { | |
518 | /* | |
519 | * If ext3_write_super() recently started a commit, then we | |
520 | * have to wait for completion of that transaction | |
521 | */ | |
522 | *ptid = journal->j_committing_transaction->t_tid; | |
523 | ret = 1; | |
524 | } | |
525 | spin_unlock(&journal->j_state_lock); | |
526 | return ret; | |
527 | } | |
528 | ||
529 | /* | |
530 | * Wait for a specified commit to complete. | |
531 | * The caller may not hold the journal lock. | |
532 | */ | |
533 | int log_wait_commit(journal_t *journal, tid_t tid) | |
534 | { | |
535 | int err = 0; | |
536 | ||
537 | #ifdef CONFIG_JBD_DEBUG | |
538 | spin_lock(&journal->j_state_lock); | |
539 | if (!tid_geq(journal->j_commit_request, tid)) { | |
540 | printk(KERN_EMERG | |
541 | "%s: error: j_commit_request=%d, tid=%d\n", | |
542 | __FUNCTION__, journal->j_commit_request, tid); | |
543 | } | |
544 | spin_unlock(&journal->j_state_lock); | |
545 | #endif | |
546 | spin_lock(&journal->j_state_lock); | |
547 | while (tid_gt(tid, journal->j_commit_sequence)) { | |
548 | jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n", | |
549 | tid, journal->j_commit_sequence); | |
550 | wake_up(&journal->j_wait_commit); | |
551 | spin_unlock(&journal->j_state_lock); | |
552 | wait_event(journal->j_wait_done_commit, | |
553 | !tid_gt(tid, journal->j_commit_sequence)); | |
554 | spin_lock(&journal->j_state_lock); | |
555 | } | |
556 | spin_unlock(&journal->j_state_lock); | |
557 | ||
558 | if (unlikely(is_journal_aborted(journal))) { | |
559 | printk(KERN_EMERG "journal commit I/O error\n"); | |
560 | err = -EIO; | |
561 | } | |
562 | return err; | |
563 | } | |
564 | ||
565 | /* | |
566 | * Log buffer allocation routines: | |
567 | */ | |
568 | ||
569 | int journal_next_log_block(journal_t *journal, unsigned long *retp) | |
570 | { | |
571 | unsigned long blocknr; | |
572 | ||
573 | spin_lock(&journal->j_state_lock); | |
574 | J_ASSERT(journal->j_free > 1); | |
575 | ||
576 | blocknr = journal->j_head; | |
577 | journal->j_head++; | |
578 | journal->j_free--; | |
579 | if (journal->j_head == journal->j_last) | |
580 | journal->j_head = journal->j_first; | |
581 | spin_unlock(&journal->j_state_lock); | |
582 | return journal_bmap(journal, blocknr, retp); | |
583 | } | |
584 | ||
585 | /* | |
586 | * Conversion of logical to physical block numbers for the journal | |
587 | * | |
588 | * On external journals the journal blocks are identity-mapped, so | |
589 | * this is a no-op. If needed, we can use j_blk_offset - everything is | |
590 | * ready. | |
591 | */ | |
592 | int journal_bmap(journal_t *journal, unsigned long blocknr, | |
593 | unsigned long *retp) | |
594 | { | |
595 | int err = 0; | |
596 | unsigned long ret; | |
597 | ||
598 | if (journal->j_inode) { | |
599 | ret = bmap(journal->j_inode, blocknr); | |
600 | if (ret) | |
601 | *retp = ret; | |
602 | else { | |
603 | char b[BDEVNAME_SIZE]; | |
604 | ||
605 | printk(KERN_ALERT "%s: journal block not found " | |
606 | "at offset %lu on %s\n", | |
607 | __FUNCTION__, | |
608 | blocknr, | |
609 | bdevname(journal->j_dev, b)); | |
610 | err = -EIO; | |
611 | __journal_abort_soft(journal, err); | |
612 | } | |
613 | } else { | |
614 | *retp = blocknr; /* +journal->j_blk_offset */ | |
615 | } | |
616 | return err; | |
617 | } | |
618 | ||
619 | /* | |
620 | * We play buffer_head aliasing tricks to write data/metadata blocks to | |
621 | * the journal without copying their contents, but for journal | |
622 | * descriptor blocks we do need to generate bona fide buffers. | |
623 | * | |
624 | * After the caller of journal_get_descriptor_buffer() has finished modifying | |
625 | * the buffer's contents they really should run flush_dcache_page(bh->b_page). | |
626 | * But we don't bother doing that, so there will be coherency problems with | |
627 | * mmaps of blockdevs which hold live JBD-controlled filesystems. | |
628 | */ | |
629 | struct journal_head *journal_get_descriptor_buffer(journal_t *journal) | |
630 | { | |
631 | struct buffer_head *bh; | |
632 | unsigned long blocknr; | |
633 | int err; | |
634 | ||
635 | err = journal_next_log_block(journal, &blocknr); | |
636 | ||
637 | if (err) | |
638 | return NULL; | |
639 | ||
640 | bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); | |
641 | lock_buffer(bh); | |
642 | memset(bh->b_data, 0, journal->j_blocksize); | |
643 | set_buffer_uptodate(bh); | |
644 | unlock_buffer(bh); | |
645 | BUFFER_TRACE(bh, "return this buffer"); | |
646 | return journal_add_journal_head(bh); | |
647 | } | |
648 | ||
649 | /* | |
650 | * Management for journal control blocks: functions to create and | |
651 | * destroy journal_t structures, and to initialise and read existing | |
652 | * journal blocks from disk. */ | |
653 | ||
654 | /* First: create and setup a journal_t object in memory. We initialise | |
655 | * very few fields yet: that has to wait until we have created the | |
656 | * journal structures from from scratch, or loaded them from disk. */ | |
657 | ||
658 | static journal_t * journal_init_common (void) | |
659 | { | |
660 | journal_t *journal; | |
661 | int err; | |
662 | ||
663 | journal = jbd_kmalloc(sizeof(*journal), GFP_KERNEL); | |
664 | if (!journal) | |
665 | goto fail; | |
666 | memset(journal, 0, sizeof(*journal)); | |
667 | ||
668 | init_waitqueue_head(&journal->j_wait_transaction_locked); | |
669 | init_waitqueue_head(&journal->j_wait_logspace); | |
670 | init_waitqueue_head(&journal->j_wait_done_commit); | |
671 | init_waitqueue_head(&journal->j_wait_checkpoint); | |
672 | init_waitqueue_head(&journal->j_wait_commit); | |
673 | init_waitqueue_head(&journal->j_wait_updates); | |
674 | init_MUTEX(&journal->j_barrier); | |
675 | init_MUTEX(&journal->j_checkpoint_sem); | |
676 | spin_lock_init(&journal->j_revoke_lock); | |
677 | spin_lock_init(&journal->j_list_lock); | |
678 | spin_lock_init(&journal->j_state_lock); | |
679 | ||
680 | journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE); | |
681 | ||
682 | /* The journal is marked for error until we succeed with recovery! */ | |
683 | journal->j_flags = JFS_ABORT; | |
684 | ||
685 | /* Set up a default-sized revoke table for the new mount. */ | |
686 | err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH); | |
687 | if (err) { | |
688 | kfree(journal); | |
689 | goto fail; | |
690 | } | |
691 | return journal; | |
692 | fail: | |
693 | return NULL; | |
694 | } | |
695 | ||
696 | /* journal_init_dev and journal_init_inode: | |
697 | * | |
698 | * Create a journal structure assigned some fixed set of disk blocks to | |
699 | * the journal. We don't actually touch those disk blocks yet, but we | |
700 | * need to set up all of the mapping information to tell the journaling | |
701 | * system where the journal blocks are. | |
702 | * | |
703 | */ | |
704 | ||
705 | /** | |
706 | * journal_t * journal_init_dev() - creates an initialises a journal structure | |
707 | * @bdev: Block device on which to create the journal | |
708 | * @fs_dev: Device which hold journalled filesystem for this journal. | |
709 | * @start: Block nr Start of journal. | |
710 | * @len: Lenght of the journal in blocks. | |
711 | * @blocksize: blocksize of journalling device | |
712 | * @returns: a newly created journal_t * | |
713 | * | |
714 | * journal_init_dev creates a journal which maps a fixed contiguous | |
715 | * range of blocks on an arbitrary block device. | |
716 | * | |
717 | */ | |
718 | journal_t * journal_init_dev(struct block_device *bdev, | |
719 | struct block_device *fs_dev, | |
720 | int start, int len, int blocksize) | |
721 | { | |
722 | journal_t *journal = journal_init_common(); | |
723 | struct buffer_head *bh; | |
724 | int n; | |
725 | ||
726 | if (!journal) | |
727 | return NULL; | |
728 | ||
729 | journal->j_dev = bdev; | |
730 | journal->j_fs_dev = fs_dev; | |
731 | journal->j_blk_offset = start; | |
732 | journal->j_maxlen = len; | |
733 | journal->j_blocksize = blocksize; | |
734 | ||
735 | bh = __getblk(journal->j_dev, start, journal->j_blocksize); | |
736 | J_ASSERT(bh != NULL); | |
737 | journal->j_sb_buffer = bh; | |
738 | journal->j_superblock = (journal_superblock_t *)bh->b_data; | |
739 | ||
740 | /* journal descriptor can store up to n blocks -bzzz */ | |
741 | n = journal->j_blocksize / sizeof(journal_block_tag_t); | |
742 | journal->j_wbufsize = n; | |
743 | journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); | |
744 | if (!journal->j_wbuf) { | |
745 | printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n", | |
746 | __FUNCTION__); | |
747 | kfree(journal); | |
748 | journal = NULL; | |
749 | } | |
750 | ||
751 | return journal; | |
752 | } | |
753 | ||
754 | /** | |
755 | * journal_t * journal_init_inode () - creates a journal which maps to a inode. | |
756 | * @inode: An inode to create the journal in | |
757 | * | |
758 | * journal_init_inode creates a journal which maps an on-disk inode as | |
759 | * the journal. The inode must exist already, must support bmap() and | |
760 | * must have all data blocks preallocated. | |
761 | */ | |
762 | journal_t * journal_init_inode (struct inode *inode) | |
763 | { | |
764 | struct buffer_head *bh; | |
765 | journal_t *journal = journal_init_common(); | |
766 | int err; | |
767 | int n; | |
768 | unsigned long blocknr; | |
769 | ||
770 | if (!journal) | |
771 | return NULL; | |
772 | ||
773 | journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev; | |
774 | journal->j_inode = inode; | |
775 | jbd_debug(1, | |
776 | "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n", | |
777 | journal, inode->i_sb->s_id, inode->i_ino, | |
778 | (long long) inode->i_size, | |
779 | inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize); | |
780 | ||
781 | journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits; | |
782 | journal->j_blocksize = inode->i_sb->s_blocksize; | |
783 | ||
784 | /* journal descriptor can store up to n blocks -bzzz */ | |
785 | n = journal->j_blocksize / sizeof(journal_block_tag_t); | |
786 | journal->j_wbufsize = n; | |
787 | journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); | |
788 | if (!journal->j_wbuf) { | |
789 | printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n", | |
790 | __FUNCTION__); | |
791 | kfree(journal); | |
792 | return NULL; | |
793 | } | |
794 | ||
795 | err = journal_bmap(journal, 0, &blocknr); | |
796 | /* If that failed, give up */ | |
797 | if (err) { | |
798 | printk(KERN_ERR "%s: Cannnot locate journal superblock\n", | |
799 | __FUNCTION__); | |
800 | kfree(journal); | |
801 | return NULL; | |
802 | } | |
803 | ||
804 | bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); | |
805 | J_ASSERT(bh != NULL); | |
806 | journal->j_sb_buffer = bh; | |
807 | journal->j_superblock = (journal_superblock_t *)bh->b_data; | |
808 | ||
809 | return journal; | |
810 | } | |
811 | ||
812 | /* | |
813 | * If the journal init or create aborts, we need to mark the journal | |
814 | * superblock as being NULL to prevent the journal destroy from writing | |
815 | * back a bogus superblock. | |
816 | */ | |
817 | static void journal_fail_superblock (journal_t *journal) | |
818 | { | |
819 | struct buffer_head *bh = journal->j_sb_buffer; | |
820 | brelse(bh); | |
821 | journal->j_sb_buffer = NULL; | |
822 | } | |
823 | ||
824 | /* | |
825 | * Given a journal_t structure, initialise the various fields for | |
826 | * startup of a new journaling session. We use this both when creating | |
827 | * a journal, and after recovering an old journal to reset it for | |
828 | * subsequent use. | |
829 | */ | |
830 | ||
831 | static int journal_reset(journal_t *journal) | |
832 | { | |
833 | journal_superblock_t *sb = journal->j_superblock; | |
834 | unsigned int first, last; | |
835 | ||
836 | first = be32_to_cpu(sb->s_first); | |
837 | last = be32_to_cpu(sb->s_maxlen); | |
838 | ||
839 | journal->j_first = first; | |
840 | journal->j_last = last; | |
841 | ||
842 | journal->j_head = first; | |
843 | journal->j_tail = first; | |
844 | journal->j_free = last - first; | |
845 | ||
846 | journal->j_tail_sequence = journal->j_transaction_sequence; | |
847 | journal->j_commit_sequence = journal->j_transaction_sequence - 1; | |
848 | journal->j_commit_request = journal->j_commit_sequence; | |
849 | ||
850 | journal->j_max_transaction_buffers = journal->j_maxlen / 4; | |
851 | ||
852 | /* Add the dynamic fields and write it to disk. */ | |
853 | journal_update_superblock(journal, 1); | |
854 | journal_start_thread(journal); | |
855 | return 0; | |
856 | } | |
857 | ||
858 | /** | |
859 | * int journal_create() - Initialise the new journal file | |
860 | * @journal: Journal to create. This structure must have been initialised | |
861 | * | |
862 | * Given a journal_t structure which tells us which disk blocks we can | |
863 | * use, create a new journal superblock and initialise all of the | |
864 | * journal fields from scratch. | |
865 | **/ | |
866 | int journal_create(journal_t *journal) | |
867 | { | |
868 | unsigned long blocknr; | |
869 | struct buffer_head *bh; | |
870 | journal_superblock_t *sb; | |
871 | int i, err; | |
872 | ||
873 | if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) { | |
874 | printk (KERN_ERR "Journal length (%d blocks) too short.\n", | |
875 | journal->j_maxlen); | |
876 | journal_fail_superblock(journal); | |
877 | return -EINVAL; | |
878 | } | |
879 | ||
880 | if (journal->j_inode == NULL) { | |
881 | /* | |
882 | * We don't know what block to start at! | |
883 | */ | |
884 | printk(KERN_EMERG | |
885 | "%s: creation of journal on external device!\n", | |
886 | __FUNCTION__); | |
887 | BUG(); | |
888 | } | |
889 | ||
890 | /* Zero out the entire journal on disk. We cannot afford to | |
891 | have any blocks on disk beginning with JFS_MAGIC_NUMBER. */ | |
892 | jbd_debug(1, "JBD: Zeroing out journal blocks...\n"); | |
893 | for (i = 0; i < journal->j_maxlen; i++) { | |
894 | err = journal_bmap(journal, i, &blocknr); | |
895 | if (err) | |
896 | return err; | |
897 | bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); | |
898 | lock_buffer(bh); | |
899 | memset (bh->b_data, 0, journal->j_blocksize); | |
900 | BUFFER_TRACE(bh, "marking dirty"); | |
901 | mark_buffer_dirty(bh); | |
902 | BUFFER_TRACE(bh, "marking uptodate"); | |
903 | set_buffer_uptodate(bh); | |
904 | unlock_buffer(bh); | |
905 | __brelse(bh); | |
906 | } | |
907 | ||
908 | sync_blockdev(journal->j_dev); | |
909 | jbd_debug(1, "JBD: journal cleared.\n"); | |
910 | ||
911 | /* OK, fill in the initial static fields in the new superblock */ | |
912 | sb = journal->j_superblock; | |
913 | ||
914 | sb->s_header.h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
915 | sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2); | |
916 | ||
917 | sb->s_blocksize = cpu_to_be32(journal->j_blocksize); | |
918 | sb->s_maxlen = cpu_to_be32(journal->j_maxlen); | |
919 | sb->s_first = cpu_to_be32(1); | |
920 | ||
921 | journal->j_transaction_sequence = 1; | |
922 | ||
923 | journal->j_flags &= ~JFS_ABORT; | |
924 | journal->j_format_version = 2; | |
925 | ||
926 | return journal_reset(journal); | |
927 | } | |
928 | ||
929 | /** | |
930 | * void journal_update_superblock() - Update journal sb on disk. | |
931 | * @journal: The journal to update. | |
932 | * @wait: Set to '0' if you don't want to wait for IO completion. | |
933 | * | |
934 | * Update a journal's dynamic superblock fields and write it to disk, | |
935 | * optionally waiting for the IO to complete. | |
936 | */ | |
937 | void journal_update_superblock(journal_t *journal, int wait) | |
938 | { | |
939 | journal_superblock_t *sb = journal->j_superblock; | |
940 | struct buffer_head *bh = journal->j_sb_buffer; | |
941 | ||
942 | /* | |
943 | * As a special case, if the on-disk copy is already marked as needing | |
944 | * no recovery (s_start == 0) and there are no outstanding transactions | |
945 | * in the filesystem, then we can safely defer the superblock update | |
946 | * until the next commit by setting JFS_FLUSHED. This avoids | |
947 | * attempting a write to a potential-readonly device. | |
948 | */ | |
949 | if (sb->s_start == 0 && journal->j_tail_sequence == | |
950 | journal->j_transaction_sequence) { | |
951 | jbd_debug(1,"JBD: Skipping superblock update on recovered sb " | |
952 | "(start %ld, seq %d, errno %d)\n", | |
953 | journal->j_tail, journal->j_tail_sequence, | |
954 | journal->j_errno); | |
955 | goto out; | |
956 | } | |
957 | ||
958 | spin_lock(&journal->j_state_lock); | |
959 | jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n", | |
960 | journal->j_tail, journal->j_tail_sequence, journal->j_errno); | |
961 | ||
962 | sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); | |
963 | sb->s_start = cpu_to_be32(journal->j_tail); | |
964 | sb->s_errno = cpu_to_be32(journal->j_errno); | |
965 | spin_unlock(&journal->j_state_lock); | |
966 | ||
967 | BUFFER_TRACE(bh, "marking dirty"); | |
968 | mark_buffer_dirty(bh); | |
969 | if (wait) | |
970 | sync_dirty_buffer(bh); | |
971 | else | |
972 | ll_rw_block(WRITE, 1, &bh); | |
973 | ||
974 | out: | |
975 | /* If we have just flushed the log (by marking s_start==0), then | |
976 | * any future commit will have to be careful to update the | |
977 | * superblock again to re-record the true start of the log. */ | |
978 | ||
979 | spin_lock(&journal->j_state_lock); | |
980 | if (sb->s_start) | |
981 | journal->j_flags &= ~JFS_FLUSHED; | |
982 | else | |
983 | journal->j_flags |= JFS_FLUSHED; | |
984 | spin_unlock(&journal->j_state_lock); | |
985 | } | |
986 | ||
987 | /* | |
988 | * Read the superblock for a given journal, performing initial | |
989 | * validation of the format. | |
990 | */ | |
991 | ||
992 | static int journal_get_superblock(journal_t *journal) | |
993 | { | |
994 | struct buffer_head *bh; | |
995 | journal_superblock_t *sb; | |
996 | int err = -EIO; | |
997 | ||
998 | bh = journal->j_sb_buffer; | |
999 | ||
1000 | J_ASSERT(bh != NULL); | |
1001 | if (!buffer_uptodate(bh)) { | |
1002 | ll_rw_block(READ, 1, &bh); | |
1003 | wait_on_buffer(bh); | |
1004 | if (!buffer_uptodate(bh)) { | |
1005 | printk (KERN_ERR | |
1006 | "JBD: IO error reading journal superblock\n"); | |
1007 | goto out; | |
1008 | } | |
1009 | } | |
1010 | ||
1011 | sb = journal->j_superblock; | |
1012 | ||
1013 | err = -EINVAL; | |
1014 | ||
1015 | if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) || | |
1016 | sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) { | |
1017 | printk(KERN_WARNING "JBD: no valid journal superblock found\n"); | |
1018 | goto out; | |
1019 | } | |
1020 | ||
1021 | switch(be32_to_cpu(sb->s_header.h_blocktype)) { | |
1022 | case JFS_SUPERBLOCK_V1: | |
1023 | journal->j_format_version = 1; | |
1024 | break; | |
1025 | case JFS_SUPERBLOCK_V2: | |
1026 | journal->j_format_version = 2; | |
1027 | break; | |
1028 | default: | |
1029 | printk(KERN_WARNING "JBD: unrecognised superblock format ID\n"); | |
1030 | goto out; | |
1031 | } | |
1032 | ||
1033 | if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen) | |
1034 | journal->j_maxlen = be32_to_cpu(sb->s_maxlen); | |
1035 | else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) { | |
1036 | printk (KERN_WARNING "JBD: journal file too short\n"); | |
1037 | goto out; | |
1038 | } | |
1039 | ||
1040 | return 0; | |
1041 | ||
1042 | out: | |
1043 | journal_fail_superblock(journal); | |
1044 | return err; | |
1045 | } | |
1046 | ||
1047 | /* | |
1048 | * Load the on-disk journal superblock and read the key fields into the | |
1049 | * journal_t. | |
1050 | */ | |
1051 | ||
1052 | static int load_superblock(journal_t *journal) | |
1053 | { | |
1054 | int err; | |
1055 | journal_superblock_t *sb; | |
1056 | ||
1057 | err = journal_get_superblock(journal); | |
1058 | if (err) | |
1059 | return err; | |
1060 | ||
1061 | sb = journal->j_superblock; | |
1062 | ||
1063 | journal->j_tail_sequence = be32_to_cpu(sb->s_sequence); | |
1064 | journal->j_tail = be32_to_cpu(sb->s_start); | |
1065 | journal->j_first = be32_to_cpu(sb->s_first); | |
1066 | journal->j_last = be32_to_cpu(sb->s_maxlen); | |
1067 | journal->j_errno = be32_to_cpu(sb->s_errno); | |
1068 | ||
1069 | return 0; | |
1070 | } | |
1071 | ||
1072 | ||
1073 | /** | |
1074 | * int journal_load() - Read journal from disk. | |
1075 | * @journal: Journal to act on. | |
1076 | * | |
1077 | * Given a journal_t structure which tells us which disk blocks contain | |
1078 | * a journal, read the journal from disk to initialise the in-memory | |
1079 | * structures. | |
1080 | */ | |
1081 | int journal_load(journal_t *journal) | |
1082 | { | |
1083 | int err; | |
1084 | ||
1085 | err = load_superblock(journal); | |
1086 | if (err) | |
1087 | return err; | |
1088 | ||
1089 | /* If this is a V2 superblock, then we have to check the | |
1090 | * features flags on it. */ | |
1091 | ||
1092 | if (journal->j_format_version >= 2) { | |
1093 | journal_superblock_t *sb = journal->j_superblock; | |
1094 | ||
1095 | if ((sb->s_feature_ro_compat & | |
1096 | ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) || | |
1097 | (sb->s_feature_incompat & | |
1098 | ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) { | |
1099 | printk (KERN_WARNING | |
1100 | "JBD: Unrecognised features on journal\n"); | |
1101 | return -EINVAL; | |
1102 | } | |
1103 | } | |
1104 | ||
1105 | /* Let the recovery code check whether it needs to recover any | |
1106 | * data from the journal. */ | |
1107 | if (journal_recover(journal)) | |
1108 | goto recovery_error; | |
1109 | ||
1110 | /* OK, we've finished with the dynamic journal bits: | |
1111 | * reinitialise the dynamic contents of the superblock in memory | |
1112 | * and reset them on disk. */ | |
1113 | if (journal_reset(journal)) | |
1114 | goto recovery_error; | |
1115 | ||
1116 | journal->j_flags &= ~JFS_ABORT; | |
1117 | journal->j_flags |= JFS_LOADED; | |
1118 | return 0; | |
1119 | ||
1120 | recovery_error: | |
1121 | printk (KERN_WARNING "JBD: recovery failed\n"); | |
1122 | return -EIO; | |
1123 | } | |
1124 | ||
1125 | /** | |
1126 | * void journal_destroy() - Release a journal_t structure. | |
1127 | * @journal: Journal to act on. | |
1128 | * | |
1129 | * Release a journal_t structure once it is no longer in use by the | |
1130 | * journaled object. | |
1131 | */ | |
1132 | void journal_destroy(journal_t *journal) | |
1133 | { | |
1134 | /* Wait for the commit thread to wake up and die. */ | |
1135 | journal_kill_thread(journal); | |
1136 | ||
1137 | /* Force a final log commit */ | |
1138 | if (journal->j_running_transaction) | |
1139 | journal_commit_transaction(journal); | |
1140 | ||
1141 | /* Force any old transactions to disk */ | |
1142 | ||
1143 | /* Totally anal locking here... */ | |
1144 | spin_lock(&journal->j_list_lock); | |
1145 | while (journal->j_checkpoint_transactions != NULL) { | |
1146 | spin_unlock(&journal->j_list_lock); | |
1147 | log_do_checkpoint(journal); | |
1148 | spin_lock(&journal->j_list_lock); | |
1149 | } | |
1150 | ||
1151 | J_ASSERT(journal->j_running_transaction == NULL); | |
1152 | J_ASSERT(journal->j_committing_transaction == NULL); | |
1153 | J_ASSERT(journal->j_checkpoint_transactions == NULL); | |
1154 | spin_unlock(&journal->j_list_lock); | |
1155 | ||
1156 | /* We can now mark the journal as empty. */ | |
1157 | journal->j_tail = 0; | |
1158 | journal->j_tail_sequence = ++journal->j_transaction_sequence; | |
1159 | if (journal->j_sb_buffer) { | |
1160 | journal_update_superblock(journal, 1); | |
1161 | brelse(journal->j_sb_buffer); | |
1162 | } | |
1163 | ||
1164 | if (journal->j_inode) | |
1165 | iput(journal->j_inode); | |
1166 | if (journal->j_revoke) | |
1167 | journal_destroy_revoke(journal); | |
1168 | kfree(journal->j_wbuf); | |
1169 | kfree(journal); | |
1170 | } | |
1171 | ||
1172 | ||
1173 | /** | |
1174 | *int journal_check_used_features () - Check if features specified are used. | |
1175 | * @journal: Journal to check. | |
1176 | * @compat: bitmask of compatible features | |
1177 | * @ro: bitmask of features that force read-only mount | |
1178 | * @incompat: bitmask of incompatible features | |
1179 | * | |
1180 | * Check whether the journal uses all of a given set of | |
1181 | * features. Return true (non-zero) if it does. | |
1182 | **/ | |
1183 | ||
1184 | int journal_check_used_features (journal_t *journal, unsigned long compat, | |
1185 | unsigned long ro, unsigned long incompat) | |
1186 | { | |
1187 | journal_superblock_t *sb; | |
1188 | ||
1189 | if (!compat && !ro && !incompat) | |
1190 | return 1; | |
1191 | if (journal->j_format_version == 1) | |
1192 | return 0; | |
1193 | ||
1194 | sb = journal->j_superblock; | |
1195 | ||
1196 | if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) && | |
1197 | ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) && | |
1198 | ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat)) | |
1199 | return 1; | |
1200 | ||
1201 | return 0; | |
1202 | } | |
1203 | ||
1204 | /** | |
1205 | * int journal_check_available_features() - Check feature set in journalling layer | |
1206 | * @journal: Journal to check. | |
1207 | * @compat: bitmask of compatible features | |
1208 | * @ro: bitmask of features that force read-only mount | |
1209 | * @incompat: bitmask of incompatible features | |
1210 | * | |
1211 | * Check whether the journaling code supports the use of | |
1212 | * all of a given set of features on this journal. Return true | |
1213 | * (non-zero) if it can. */ | |
1214 | ||
1215 | int journal_check_available_features (journal_t *journal, unsigned long compat, | |
1216 | unsigned long ro, unsigned long incompat) | |
1217 | { | |
1218 | journal_superblock_t *sb; | |
1219 | ||
1220 | if (!compat && !ro && !incompat) | |
1221 | return 1; | |
1222 | ||
1223 | sb = journal->j_superblock; | |
1224 | ||
1225 | /* We can support any known requested features iff the | |
1226 | * superblock is in version 2. Otherwise we fail to support any | |
1227 | * extended sb features. */ | |
1228 | ||
1229 | if (journal->j_format_version != 2) | |
1230 | return 0; | |
1231 | ||
1232 | if ((compat & JFS_KNOWN_COMPAT_FEATURES) == compat && | |
1233 | (ro & JFS_KNOWN_ROCOMPAT_FEATURES) == ro && | |
1234 | (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat) | |
1235 | return 1; | |
1236 | ||
1237 | return 0; | |
1238 | } | |
1239 | ||
1240 | /** | |
1241 | * int journal_set_features () - Mark a given journal feature in the superblock | |
1242 | * @journal: Journal to act on. | |
1243 | * @compat: bitmask of compatible features | |
1244 | * @ro: bitmask of features that force read-only mount | |
1245 | * @incompat: bitmask of incompatible features | |
1246 | * | |
1247 | * Mark a given journal feature as present on the | |
1248 | * superblock. Returns true if the requested features could be set. | |
1249 | * | |
1250 | */ | |
1251 | ||
1252 | int journal_set_features (journal_t *journal, unsigned long compat, | |
1253 | unsigned long ro, unsigned long incompat) | |
1254 | { | |
1255 | journal_superblock_t *sb; | |
1256 | ||
1257 | if (journal_check_used_features(journal, compat, ro, incompat)) | |
1258 | return 1; | |
1259 | ||
1260 | if (!journal_check_available_features(journal, compat, ro, incompat)) | |
1261 | return 0; | |
1262 | ||
1263 | jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n", | |
1264 | compat, ro, incompat); | |
1265 | ||
1266 | sb = journal->j_superblock; | |
1267 | ||
1268 | sb->s_feature_compat |= cpu_to_be32(compat); | |
1269 | sb->s_feature_ro_compat |= cpu_to_be32(ro); | |
1270 | sb->s_feature_incompat |= cpu_to_be32(incompat); | |
1271 | ||
1272 | return 1; | |
1273 | } | |
1274 | ||
1275 | ||
1276 | /** | |
1277 | * int journal_update_format () - Update on-disk journal structure. | |
1278 | * @journal: Journal to act on. | |
1279 | * | |
1280 | * Given an initialised but unloaded journal struct, poke about in the | |
1281 | * on-disk structure to update it to the most recent supported version. | |
1282 | */ | |
1283 | int journal_update_format (journal_t *journal) | |
1284 | { | |
1285 | journal_superblock_t *sb; | |
1286 | int err; | |
1287 | ||
1288 | err = journal_get_superblock(journal); | |
1289 | if (err) | |
1290 | return err; | |
1291 | ||
1292 | sb = journal->j_superblock; | |
1293 | ||
1294 | switch (be32_to_cpu(sb->s_header.h_blocktype)) { | |
1295 | case JFS_SUPERBLOCK_V2: | |
1296 | return 0; | |
1297 | case JFS_SUPERBLOCK_V1: | |
1298 | return journal_convert_superblock_v1(journal, sb); | |
1299 | default: | |
1300 | break; | |
1301 | } | |
1302 | return -EINVAL; | |
1303 | } | |
1304 | ||
1305 | static int journal_convert_superblock_v1(journal_t *journal, | |
1306 | journal_superblock_t *sb) | |
1307 | { | |
1308 | int offset, blocksize; | |
1309 | struct buffer_head *bh; | |
1310 | ||
1311 | printk(KERN_WARNING | |
1312 | "JBD: Converting superblock from version 1 to 2.\n"); | |
1313 | ||
1314 | /* Pre-initialise new fields to zero */ | |
1315 | offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb); | |
1316 | blocksize = be32_to_cpu(sb->s_blocksize); | |
1317 | memset(&sb->s_feature_compat, 0, blocksize-offset); | |
1318 | ||
1319 | sb->s_nr_users = cpu_to_be32(1); | |
1320 | sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2); | |
1321 | journal->j_format_version = 2; | |
1322 | ||
1323 | bh = journal->j_sb_buffer; | |
1324 | BUFFER_TRACE(bh, "marking dirty"); | |
1325 | mark_buffer_dirty(bh); | |
1326 | sync_dirty_buffer(bh); | |
1327 | return 0; | |
1328 | } | |
1329 | ||
1330 | ||
1331 | /** | |
1332 | * int journal_flush () - Flush journal | |
1333 | * @journal: Journal to act on. | |
1334 | * | |
1335 | * Flush all data for a given journal to disk and empty the journal. | |
1336 | * Filesystems can use this when remounting readonly to ensure that | |
1337 | * recovery does not need to happen on remount. | |
1338 | */ | |
1339 | ||
1340 | int journal_flush(journal_t *journal) | |
1341 | { | |
1342 | int err = 0; | |
1343 | transaction_t *transaction = NULL; | |
1344 | unsigned long old_tail; | |
1345 | ||
1346 | spin_lock(&journal->j_state_lock); | |
1347 | ||
1348 | /* Force everything buffered to the log... */ | |
1349 | if (journal->j_running_transaction) { | |
1350 | transaction = journal->j_running_transaction; | |
1351 | __log_start_commit(journal, transaction->t_tid); | |
1352 | } else if (journal->j_committing_transaction) | |
1353 | transaction = journal->j_committing_transaction; | |
1354 | ||
1355 | /* Wait for the log commit to complete... */ | |
1356 | if (transaction) { | |
1357 | tid_t tid = transaction->t_tid; | |
1358 | ||
1359 | spin_unlock(&journal->j_state_lock); | |
1360 | log_wait_commit(journal, tid); | |
1361 | } else { | |
1362 | spin_unlock(&journal->j_state_lock); | |
1363 | } | |
1364 | ||
1365 | /* ...and flush everything in the log out to disk. */ | |
1366 | spin_lock(&journal->j_list_lock); | |
1367 | while (!err && journal->j_checkpoint_transactions != NULL) { | |
1368 | spin_unlock(&journal->j_list_lock); | |
1369 | err = log_do_checkpoint(journal); | |
1370 | spin_lock(&journal->j_list_lock); | |
1371 | } | |
1372 | spin_unlock(&journal->j_list_lock); | |
1373 | cleanup_journal_tail(journal); | |
1374 | ||
1375 | /* Finally, mark the journal as really needing no recovery. | |
1376 | * This sets s_start==0 in the underlying superblock, which is | |
1377 | * the magic code for a fully-recovered superblock. Any future | |
1378 | * commits of data to the journal will restore the current | |
1379 | * s_start value. */ | |
1380 | spin_lock(&journal->j_state_lock); | |
1381 | old_tail = journal->j_tail; | |
1382 | journal->j_tail = 0; | |
1383 | spin_unlock(&journal->j_state_lock); | |
1384 | journal_update_superblock(journal, 1); | |
1385 | spin_lock(&journal->j_state_lock); | |
1386 | journal->j_tail = old_tail; | |
1387 | ||
1388 | J_ASSERT(!journal->j_running_transaction); | |
1389 | J_ASSERT(!journal->j_committing_transaction); | |
1390 | J_ASSERT(!journal->j_checkpoint_transactions); | |
1391 | J_ASSERT(journal->j_head == journal->j_tail); | |
1392 | J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence); | |
1393 | spin_unlock(&journal->j_state_lock); | |
1394 | return err; | |
1395 | } | |
1396 | ||
1397 | /** | |
1398 | * int journal_wipe() - Wipe journal contents | |
1399 | * @journal: Journal to act on. | |
1400 | * @write: flag (see below) | |
1401 | * | |
1402 | * Wipe out all of the contents of a journal, safely. This will produce | |
1403 | * a warning if the journal contains any valid recovery information. | |
1404 | * Must be called between journal_init_*() and journal_load(). | |
1405 | * | |
1406 | * If 'write' is non-zero, then we wipe out the journal on disk; otherwise | |
1407 | * we merely suppress recovery. | |
1408 | */ | |
1409 | ||
1410 | int journal_wipe(journal_t *journal, int write) | |
1411 | { | |
1412 | journal_superblock_t *sb; | |
1413 | int err = 0; | |
1414 | ||
1415 | J_ASSERT (!(journal->j_flags & JFS_LOADED)); | |
1416 | ||
1417 | err = load_superblock(journal); | |
1418 | if (err) | |
1419 | return err; | |
1420 | ||
1421 | sb = journal->j_superblock; | |
1422 | ||
1423 | if (!journal->j_tail) | |
1424 | goto no_recovery; | |
1425 | ||
1426 | printk (KERN_WARNING "JBD: %s recovery information on journal\n", | |
1427 | write ? "Clearing" : "Ignoring"); | |
1428 | ||
1429 | err = journal_skip_recovery(journal); | |
1430 | if (write) | |
1431 | journal_update_superblock(journal, 1); | |
1432 | ||
1433 | no_recovery: | |
1434 | return err; | |
1435 | } | |
1436 | ||
1437 | /* | |
1438 | * journal_dev_name: format a character string to describe on what | |
1439 | * device this journal is present. | |
1440 | */ | |
1441 | ||
1442 | const char *journal_dev_name(journal_t *journal, char *buffer) | |
1443 | { | |
1444 | struct block_device *bdev; | |
1445 | ||
1446 | if (journal->j_inode) | |
1447 | bdev = journal->j_inode->i_sb->s_bdev; | |
1448 | else | |
1449 | bdev = journal->j_dev; | |
1450 | ||
1451 | return bdevname(bdev, buffer); | |
1452 | } | |
1453 | ||
1454 | /* | |
1455 | * Journal abort has very specific semantics, which we describe | |
1456 | * for journal abort. | |
1457 | * | |
1458 | * Two internal function, which provide abort to te jbd layer | |
1459 | * itself are here. | |
1460 | */ | |
1461 | ||
1462 | /* | |
1463 | * Quick version for internal journal use (doesn't lock the journal). | |
1464 | * Aborts hard --- we mark the abort as occurred, but do _nothing_ else, | |
1465 | * and don't attempt to make any other journal updates. | |
1466 | */ | |
1467 | void __journal_abort_hard(journal_t *journal) | |
1468 | { | |
1469 | transaction_t *transaction; | |
1470 | char b[BDEVNAME_SIZE]; | |
1471 | ||
1472 | if (journal->j_flags & JFS_ABORT) | |
1473 | return; | |
1474 | ||
1475 | printk(KERN_ERR "Aborting journal on device %s.\n", | |
1476 | journal_dev_name(journal, b)); | |
1477 | ||
1478 | spin_lock(&journal->j_state_lock); | |
1479 | journal->j_flags |= JFS_ABORT; | |
1480 | transaction = journal->j_running_transaction; | |
1481 | if (transaction) | |
1482 | __log_start_commit(journal, transaction->t_tid); | |
1483 | spin_unlock(&journal->j_state_lock); | |
1484 | } | |
1485 | ||
1486 | /* Soft abort: record the abort error status in the journal superblock, | |
1487 | * but don't do any other IO. */ | |
1488 | void __journal_abort_soft (journal_t *journal, int errno) | |
1489 | { | |
1490 | if (journal->j_flags & JFS_ABORT) | |
1491 | return; | |
1492 | ||
1493 | if (!journal->j_errno) | |
1494 | journal->j_errno = errno; | |
1495 | ||
1496 | __journal_abort_hard(journal); | |
1497 | ||
1498 | if (errno) | |
1499 | journal_update_superblock(journal, 1); | |
1500 | } | |
1501 | ||
1502 | /** | |
1503 | * void journal_abort () - Shutdown the journal immediately. | |
1504 | * @journal: the journal to shutdown. | |
1505 | * @errno: an error number to record in the journal indicating | |
1506 | * the reason for the shutdown. | |
1507 | * | |
1508 | * Perform a complete, immediate shutdown of the ENTIRE | |
1509 | * journal (not of a single transaction). This operation cannot be | |
1510 | * undone without closing and reopening the journal. | |
1511 | * | |
1512 | * The journal_abort function is intended to support higher level error | |
1513 | * recovery mechanisms such as the ext2/ext3 remount-readonly error | |
1514 | * mode. | |
1515 | * | |
1516 | * Journal abort has very specific semantics. Any existing dirty, | |
1517 | * unjournaled buffers in the main filesystem will still be written to | |
1518 | * disk by bdflush, but the journaling mechanism will be suspended | |
1519 | * immediately and no further transaction commits will be honoured. | |
1520 | * | |
1521 | * Any dirty, journaled buffers will be written back to disk without | |
1522 | * hitting the journal. Atomicity cannot be guaranteed on an aborted | |
1523 | * filesystem, but we _do_ attempt to leave as much data as possible | |
1524 | * behind for fsck to use for cleanup. | |
1525 | * | |
1526 | * Any attempt to get a new transaction handle on a journal which is in | |
1527 | * ABORT state will just result in an -EROFS error return. A | |
1528 | * journal_stop on an existing handle will return -EIO if we have | |
1529 | * entered abort state during the update. | |
1530 | * | |
1531 | * Recursive transactions are not disturbed by journal abort until the | |
1532 | * final journal_stop, which will receive the -EIO error. | |
1533 | * | |
1534 | * Finally, the journal_abort call allows the caller to supply an errno | |
1535 | * which will be recorded (if possible) in the journal superblock. This | |
1536 | * allows a client to record failure conditions in the middle of a | |
1537 | * transaction without having to complete the transaction to record the | |
1538 | * failure to disk. ext3_error, for example, now uses this | |
1539 | * functionality. | |
1540 | * | |
1541 | * Errors which originate from within the journaling layer will NOT | |
1542 | * supply an errno; a null errno implies that absolutely no further | |
1543 | * writes are done to the journal (unless there are any already in | |
1544 | * progress). | |
1545 | * | |
1546 | */ | |
1547 | ||
1548 | void journal_abort(journal_t *journal, int errno) | |
1549 | { | |
1550 | __journal_abort_soft(journal, errno); | |
1551 | } | |
1552 | ||
1553 | /** | |
1554 | * int journal_errno () - returns the journal's error state. | |
1555 | * @journal: journal to examine. | |
1556 | * | |
1557 | * This is the errno numbet set with journal_abort(), the last | |
1558 | * time the journal was mounted - if the journal was stopped | |
1559 | * without calling abort this will be 0. | |
1560 | * | |
1561 | * If the journal has been aborted on this mount time -EROFS will | |
1562 | * be returned. | |
1563 | */ | |
1564 | int journal_errno(journal_t *journal) | |
1565 | { | |
1566 | int err; | |
1567 | ||
1568 | spin_lock(&journal->j_state_lock); | |
1569 | if (journal->j_flags & JFS_ABORT) | |
1570 | err = -EROFS; | |
1571 | else | |
1572 | err = journal->j_errno; | |
1573 | spin_unlock(&journal->j_state_lock); | |
1574 | return err; | |
1575 | } | |
1576 | ||
1577 | /** | |
1578 | * int journal_clear_err () - clears the journal's error state | |
1579 | * @journal: journal to act on. | |
1580 | * | |
1581 | * An error must be cleared or Acked to take a FS out of readonly | |
1582 | * mode. | |
1583 | */ | |
1584 | int journal_clear_err(journal_t *journal) | |
1585 | { | |
1586 | int err = 0; | |
1587 | ||
1588 | spin_lock(&journal->j_state_lock); | |
1589 | if (journal->j_flags & JFS_ABORT) | |
1590 | err = -EROFS; | |
1591 | else | |
1592 | journal->j_errno = 0; | |
1593 | spin_unlock(&journal->j_state_lock); | |
1594 | return err; | |
1595 | } | |
1596 | ||
1597 | /** | |
1598 | * void journal_ack_err() - Ack journal err. | |
1599 | * @journal: journal to act on. | |
1600 | * | |
1601 | * An error must be cleared or Acked to take a FS out of readonly | |
1602 | * mode. | |
1603 | */ | |
1604 | void journal_ack_err(journal_t *journal) | |
1605 | { | |
1606 | spin_lock(&journal->j_state_lock); | |
1607 | if (journal->j_errno) | |
1608 | journal->j_flags |= JFS_ACK_ERR; | |
1609 | spin_unlock(&journal->j_state_lock); | |
1610 | } | |
1611 | ||
1612 | int journal_blocks_per_page(struct inode *inode) | |
1613 | { | |
1614 | return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); | |
1615 | } | |
1616 | ||
1617 | /* | |
1618 | * Simple support for retrying memory allocations. Introduced to help to | |
1619 | * debug different VM deadlock avoidance strategies. | |
1620 | */ | |
1621 | void * __jbd_kmalloc (const char *where, size_t size, int flags, int retry) | |
1622 | { | |
1623 | return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0)); | |
1624 | } | |
1625 | ||
1626 | /* | |
1627 | * Journal_head storage management | |
1628 | */ | |
1629 | static kmem_cache_t *journal_head_cache; | |
1630 | #ifdef CONFIG_JBD_DEBUG | |
1631 | static atomic_t nr_journal_heads = ATOMIC_INIT(0); | |
1632 | #endif | |
1633 | ||
1634 | static int journal_init_journal_head_cache(void) | |
1635 | { | |
1636 | int retval; | |
1637 | ||
1638 | J_ASSERT(journal_head_cache == 0); | |
1639 | journal_head_cache = kmem_cache_create("journal_head", | |
1640 | sizeof(struct journal_head), | |
1641 | 0, /* offset */ | |
1642 | 0, /* flags */ | |
1643 | NULL, /* ctor */ | |
1644 | NULL); /* dtor */ | |
1645 | retval = 0; | |
1646 | if (journal_head_cache == 0) { | |
1647 | retval = -ENOMEM; | |
1648 | printk(KERN_EMERG "JBD: no memory for journal_head cache\n"); | |
1649 | } | |
1650 | return retval; | |
1651 | } | |
1652 | ||
1653 | static void journal_destroy_journal_head_cache(void) | |
1654 | { | |
1655 | J_ASSERT(journal_head_cache != NULL); | |
1656 | kmem_cache_destroy(journal_head_cache); | |
1657 | journal_head_cache = NULL; | |
1658 | } | |
1659 | ||
1660 | /* | |
1661 | * journal_head splicing and dicing | |
1662 | */ | |
1663 | static struct journal_head *journal_alloc_journal_head(void) | |
1664 | { | |
1665 | struct journal_head *ret; | |
1666 | static unsigned long last_warning; | |
1667 | ||
1668 | #ifdef CONFIG_JBD_DEBUG | |
1669 | atomic_inc(&nr_journal_heads); | |
1670 | #endif | |
1671 | ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS); | |
1672 | if (ret == 0) { | |
1673 | jbd_debug(1, "out of memory for journal_head\n"); | |
1674 | if (time_after(jiffies, last_warning + 5*HZ)) { | |
1675 | printk(KERN_NOTICE "ENOMEM in %s, retrying.\n", | |
1676 | __FUNCTION__); | |
1677 | last_warning = jiffies; | |
1678 | } | |
1679 | while (ret == 0) { | |
1680 | yield(); | |
1681 | ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS); | |
1682 | } | |
1683 | } | |
1684 | return ret; | |
1685 | } | |
1686 | ||
1687 | static void journal_free_journal_head(struct journal_head *jh) | |
1688 | { | |
1689 | #ifdef CONFIG_JBD_DEBUG | |
1690 | atomic_dec(&nr_journal_heads); | |
1691 | memset(jh, 0x5b, sizeof(*jh)); | |
1692 | #endif | |
1693 | kmem_cache_free(journal_head_cache, jh); | |
1694 | } | |
1695 | ||
1696 | /* | |
1697 | * A journal_head is attached to a buffer_head whenever JBD has an | |
1698 | * interest in the buffer. | |
1699 | * | |
1700 | * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit | |
1701 | * is set. This bit is tested in core kernel code where we need to take | |
1702 | * JBD-specific actions. Testing the zeroness of ->b_private is not reliable | |
1703 | * there. | |
1704 | * | |
1705 | * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one. | |
1706 | * | |
1707 | * When a buffer has its BH_JBD bit set it is immune from being released by | |
1708 | * core kernel code, mainly via ->b_count. | |
1709 | * | |
1710 | * A journal_head may be detached from its buffer_head when the journal_head's | |
1711 | * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL. | |
1712 | * Various places in JBD call journal_remove_journal_head() to indicate that the | |
1713 | * journal_head can be dropped if needed. | |
1714 | * | |
1715 | * Various places in the kernel want to attach a journal_head to a buffer_head | |
1716 | * _before_ attaching the journal_head to a transaction. To protect the | |
1717 | * journal_head in this situation, journal_add_journal_head elevates the | |
1718 | * journal_head's b_jcount refcount by one. The caller must call | |
1719 | * journal_put_journal_head() to undo this. | |
1720 | * | |
1721 | * So the typical usage would be: | |
1722 | * | |
1723 | * (Attach a journal_head if needed. Increments b_jcount) | |
1724 | * struct journal_head *jh = journal_add_journal_head(bh); | |
1725 | * ... | |
1726 | * jh->b_transaction = xxx; | |
1727 | * journal_put_journal_head(jh); | |
1728 | * | |
1729 | * Now, the journal_head's b_jcount is zero, but it is safe from being released | |
1730 | * because it has a non-zero b_transaction. | |
1731 | */ | |
1732 | ||
1733 | /* | |
1734 | * Give a buffer_head a journal_head. | |
1735 | * | |
1736 | * Doesn't need the journal lock. | |
1737 | * May sleep. | |
1738 | */ | |
1739 | struct journal_head *journal_add_journal_head(struct buffer_head *bh) | |
1740 | { | |
1741 | struct journal_head *jh; | |
1742 | struct journal_head *new_jh = NULL; | |
1743 | ||
1744 | repeat: | |
1745 | if (!buffer_jbd(bh)) { | |
1746 | new_jh = journal_alloc_journal_head(); | |
1747 | memset(new_jh, 0, sizeof(*new_jh)); | |
1748 | } | |
1749 | ||
1750 | jbd_lock_bh_journal_head(bh); | |
1751 | if (buffer_jbd(bh)) { | |
1752 | jh = bh2jh(bh); | |
1753 | } else { | |
1754 | J_ASSERT_BH(bh, | |
1755 | (atomic_read(&bh->b_count) > 0) || | |
1756 | (bh->b_page && bh->b_page->mapping)); | |
1757 | ||
1758 | if (!new_jh) { | |
1759 | jbd_unlock_bh_journal_head(bh); | |
1760 | goto repeat; | |
1761 | } | |
1762 | ||
1763 | jh = new_jh; | |
1764 | new_jh = NULL; /* We consumed it */ | |
1765 | set_buffer_jbd(bh); | |
1766 | bh->b_private = jh; | |
1767 | jh->b_bh = bh; | |
1768 | get_bh(bh); | |
1769 | BUFFER_TRACE(bh, "added journal_head"); | |
1770 | } | |
1771 | jh->b_jcount++; | |
1772 | jbd_unlock_bh_journal_head(bh); | |
1773 | if (new_jh) | |
1774 | journal_free_journal_head(new_jh); | |
1775 | return bh->b_private; | |
1776 | } | |
1777 | ||
1778 | /* | |
1779 | * Grab a ref against this buffer_head's journal_head. If it ended up not | |
1780 | * having a journal_head, return NULL | |
1781 | */ | |
1782 | struct journal_head *journal_grab_journal_head(struct buffer_head *bh) | |
1783 | { | |
1784 | struct journal_head *jh = NULL; | |
1785 | ||
1786 | jbd_lock_bh_journal_head(bh); | |
1787 | if (buffer_jbd(bh)) { | |
1788 | jh = bh2jh(bh); | |
1789 | jh->b_jcount++; | |
1790 | } | |
1791 | jbd_unlock_bh_journal_head(bh); | |
1792 | return jh; | |
1793 | } | |
1794 | ||
1795 | static void __journal_remove_journal_head(struct buffer_head *bh) | |
1796 | { | |
1797 | struct journal_head *jh = bh2jh(bh); | |
1798 | ||
1799 | J_ASSERT_JH(jh, jh->b_jcount >= 0); | |
1800 | ||
1801 | get_bh(bh); | |
1802 | if (jh->b_jcount == 0) { | |
1803 | if (jh->b_transaction == NULL && | |
1804 | jh->b_next_transaction == NULL && | |
1805 | jh->b_cp_transaction == NULL) { | |
1806 | J_ASSERT_JH(jh, jh->b_jlist == BJ_None); | |
1807 | J_ASSERT_BH(bh, buffer_jbd(bh)); | |
1808 | J_ASSERT_BH(bh, jh2bh(jh) == bh); | |
1809 | BUFFER_TRACE(bh, "remove journal_head"); | |
1810 | if (jh->b_frozen_data) { | |
1811 | printk(KERN_WARNING "%s: freeing " | |
1812 | "b_frozen_data\n", | |
1813 | __FUNCTION__); | |
1814 | kfree(jh->b_frozen_data); | |
1815 | } | |
1816 | if (jh->b_committed_data) { | |
1817 | printk(KERN_WARNING "%s: freeing " | |
1818 | "b_committed_data\n", | |
1819 | __FUNCTION__); | |
1820 | kfree(jh->b_committed_data); | |
1821 | } | |
1822 | bh->b_private = NULL; | |
1823 | jh->b_bh = NULL; /* debug, really */ | |
1824 | clear_buffer_jbd(bh); | |
1825 | __brelse(bh); | |
1826 | journal_free_journal_head(jh); | |
1827 | } else { | |
1828 | BUFFER_TRACE(bh, "journal_head was locked"); | |
1829 | } | |
1830 | } | |
1831 | } | |
1832 | ||
1833 | /* | |
1834 | * journal_remove_journal_head(): if the buffer isn't attached to a transaction | |
1835 | * and has a zero b_jcount then remove and release its journal_head. If we did | |
1836 | * see that the buffer is not used by any transaction we also "logically" | |
1837 | * decrement ->b_count. | |
1838 | * | |
1839 | * We in fact take an additional increment on ->b_count as a convenience, | |
1840 | * because the caller usually wants to do additional things with the bh | |
1841 | * after calling here. | |
1842 | * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some | |
1843 | * time. Once the caller has run __brelse(), the buffer is eligible for | |
1844 | * reaping by try_to_free_buffers(). | |
1845 | */ | |
1846 | void journal_remove_journal_head(struct buffer_head *bh) | |
1847 | { | |
1848 | jbd_lock_bh_journal_head(bh); | |
1849 | __journal_remove_journal_head(bh); | |
1850 | jbd_unlock_bh_journal_head(bh); | |
1851 | } | |
1852 | ||
1853 | /* | |
1854 | * Drop a reference on the passed journal_head. If it fell to zero then try to | |
1855 | * release the journal_head from the buffer_head. | |
1856 | */ | |
1857 | void journal_put_journal_head(struct journal_head *jh) | |
1858 | { | |
1859 | struct buffer_head *bh = jh2bh(jh); | |
1860 | ||
1861 | jbd_lock_bh_journal_head(bh); | |
1862 | J_ASSERT_JH(jh, jh->b_jcount > 0); | |
1863 | --jh->b_jcount; | |
1864 | if (!jh->b_jcount && !jh->b_transaction) { | |
1865 | __journal_remove_journal_head(bh); | |
1866 | __brelse(bh); | |
1867 | } | |
1868 | jbd_unlock_bh_journal_head(bh); | |
1869 | } | |
1870 | ||
1871 | /* | |
1872 | * /proc tunables | |
1873 | */ | |
1874 | #if defined(CONFIG_JBD_DEBUG) | |
1875 | int journal_enable_debug; | |
1876 | EXPORT_SYMBOL(journal_enable_debug); | |
1877 | #endif | |
1878 | ||
1879 | #if defined(CONFIG_JBD_DEBUG) && defined(CONFIG_PROC_FS) | |
1880 | ||
1881 | static struct proc_dir_entry *proc_jbd_debug; | |
1882 | ||
1883 | int read_jbd_debug(char *page, char **start, off_t off, | |
1884 | int count, int *eof, void *data) | |
1885 | { | |
1886 | int ret; | |
1887 | ||
1888 | ret = sprintf(page + off, "%d\n", journal_enable_debug); | |
1889 | *eof = 1; | |
1890 | return ret; | |
1891 | } | |
1892 | ||
1893 | int write_jbd_debug(struct file *file, const char __user *buffer, | |
1894 | unsigned long count, void *data) | |
1895 | { | |
1896 | char buf[32]; | |
1897 | ||
1898 | if (count > ARRAY_SIZE(buf) - 1) | |
1899 | count = ARRAY_SIZE(buf) - 1; | |
1900 | if (copy_from_user(buf, buffer, count)) | |
1901 | return -EFAULT; | |
1902 | buf[ARRAY_SIZE(buf) - 1] = '\0'; | |
1903 | journal_enable_debug = simple_strtoul(buf, NULL, 10); | |
1904 | return count; | |
1905 | } | |
1906 | ||
1907 | #define JBD_PROC_NAME "sys/fs/jbd-debug" | |
1908 | ||
1909 | static void __init create_jbd_proc_entry(void) | |
1910 | { | |
1911 | proc_jbd_debug = create_proc_entry(JBD_PROC_NAME, 0644, NULL); | |
1912 | if (proc_jbd_debug) { | |
1913 | /* Why is this so hard? */ | |
1914 | proc_jbd_debug->read_proc = read_jbd_debug; | |
1915 | proc_jbd_debug->write_proc = write_jbd_debug; | |
1916 | } | |
1917 | } | |
1918 | ||
1919 | static void __exit remove_jbd_proc_entry(void) | |
1920 | { | |
1921 | if (proc_jbd_debug) | |
1922 | remove_proc_entry(JBD_PROC_NAME, NULL); | |
1923 | } | |
1924 | ||
1925 | #else | |
1926 | ||
1927 | #define create_jbd_proc_entry() do {} while (0) | |
1928 | #define remove_jbd_proc_entry() do {} while (0) | |
1929 | ||
1930 | #endif | |
1931 | ||
1932 | kmem_cache_t *jbd_handle_cache; | |
1933 | ||
1934 | static int __init journal_init_handle_cache(void) | |
1935 | { | |
1936 | jbd_handle_cache = kmem_cache_create("journal_handle", | |
1937 | sizeof(handle_t), | |
1938 | 0, /* offset */ | |
1939 | 0, /* flags */ | |
1940 | NULL, /* ctor */ | |
1941 | NULL); /* dtor */ | |
1942 | if (jbd_handle_cache == NULL) { | |
1943 | printk(KERN_EMERG "JBD: failed to create handle cache\n"); | |
1944 | return -ENOMEM; | |
1945 | } | |
1946 | return 0; | |
1947 | } | |
1948 | ||
1949 | static void journal_destroy_handle_cache(void) | |
1950 | { | |
1951 | if (jbd_handle_cache) | |
1952 | kmem_cache_destroy(jbd_handle_cache); | |
1953 | } | |
1954 | ||
1955 | /* | |
1956 | * Module startup and shutdown | |
1957 | */ | |
1958 | ||
1959 | static int __init journal_init_caches(void) | |
1960 | { | |
1961 | int ret; | |
1962 | ||
1963 | ret = journal_init_revoke_caches(); | |
1964 | if (ret == 0) | |
1965 | ret = journal_init_journal_head_cache(); | |
1966 | if (ret == 0) | |
1967 | ret = journal_init_handle_cache(); | |
1968 | return ret; | |
1969 | } | |
1970 | ||
1971 | static void journal_destroy_caches(void) | |
1972 | { | |
1973 | journal_destroy_revoke_caches(); | |
1974 | journal_destroy_journal_head_cache(); | |
1975 | journal_destroy_handle_cache(); | |
1976 | } | |
1977 | ||
1978 | static int __init journal_init(void) | |
1979 | { | |
1980 | int ret; | |
1981 | ||
1982 | ret = journal_init_caches(); | |
1983 | if (ret != 0) | |
1984 | journal_destroy_caches(); | |
1985 | create_jbd_proc_entry(); | |
1986 | return ret; | |
1987 | } | |
1988 | ||
1989 | static void __exit journal_exit(void) | |
1990 | { | |
1991 | #ifdef CONFIG_JBD_DEBUG | |
1992 | int n = atomic_read(&nr_journal_heads); | |
1993 | if (n) | |
1994 | printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n); | |
1995 | #endif | |
1996 | remove_jbd_proc_entry(); | |
1997 | journal_destroy_caches(); | |
1998 | } | |
1999 | ||
2000 | MODULE_LICENSE("GPL"); | |
2001 | module_init(journal_init); | |
2002 | module_exit(journal_exit); | |
2003 |