Commit | Line | Data |
---|---|---|
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); | |
1da177e4 LT |
68 | EXPORT_SYMBOL(journal_update_superblock); |
69 | EXPORT_SYMBOL(journal_abort); | |
70 | EXPORT_SYMBOL(journal_errno); | |
71 | EXPORT_SYMBOL(journal_ack_err); | |
72 | EXPORT_SYMBOL(journal_clear_err); | |
73 | EXPORT_SYMBOL(log_wait_commit); | |
74 | EXPORT_SYMBOL(journal_start_commit); | |
75 | EXPORT_SYMBOL(journal_force_commit_nested); | |
76 | EXPORT_SYMBOL(journal_wipe); | |
77 | EXPORT_SYMBOL(journal_blocks_per_page); | |
78 | EXPORT_SYMBOL(journal_invalidatepage); | |
79 | EXPORT_SYMBOL(journal_try_to_free_buffers); | |
80 | EXPORT_SYMBOL(journal_force_commit); | |
81 | ||
82 | static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *); | |
022a4a7b | 83 | static void __journal_abort_soft (journal_t *journal, int errno); |
1da177e4 LT |
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 | ||
1da177e4 LT |
96 | /* |
97 | * kjournald: The main thread function used to manage a logging device | |
98 | * journal. | |
99 | * | |
100 | * This kernel thread is responsible for two things: | |
101 | * | |
102 | * 1) COMMIT: Every so often we need to commit the current state of the | |
103 | * filesystem to disk. The journal thread is responsible for writing | |
104 | * all of the metadata buffers to disk. | |
105 | * | |
106 | * 2) CHECKPOINT: We cannot reuse a used section of the log file until all | |
107 | * of the data in that part of the log has been rewritten elsewhere on | |
108 | * the disk. Flushing these old buffers to reclaim space in the log is | |
109 | * known as checkpointing, and this thread is responsible for that job. | |
110 | */ | |
111 | ||
022a4a7b | 112 | static int kjournald(void *arg) |
1da177e4 | 113 | { |
e3df1898 | 114 | journal_t *journal = arg; |
1da177e4 | 115 | transaction_t *transaction; |
1da177e4 | 116 | |
1da177e4 LT |
117 | daemonize("kjournald"); |
118 | ||
e3df1898 AM |
119 | /* |
120 | * Set up an interval timer which can be used to trigger a commit wakeup | |
121 | * after the commit interval expires | |
122 | */ | |
123 | setup_timer(&journal->j_commit_timer, commit_timeout, | |
124 | (unsigned long)current); | |
1da177e4 LT |
125 | |
126 | /* Record that the journal thread is running */ | |
127 | journal->j_task = current; | |
128 | wake_up(&journal->j_wait_done_commit); | |
129 | ||
130 | printk(KERN_INFO "kjournald starting. Commit interval %ld seconds\n", | |
131 | journal->j_commit_interval / HZ); | |
132 | ||
133 | /* | |
134 | * And now, wait forever for commit wakeup events. | |
135 | */ | |
136 | spin_lock(&journal->j_state_lock); | |
137 | ||
138 | loop: | |
139 | if (journal->j_flags & JFS_UNMOUNT) | |
140 | goto end_loop; | |
141 | ||
142 | jbd_debug(1, "commit_sequence=%d, commit_request=%d\n", | |
143 | journal->j_commit_sequence, journal->j_commit_request); | |
144 | ||
145 | if (journal->j_commit_sequence != journal->j_commit_request) { | |
146 | jbd_debug(1, "OK, requests differ\n"); | |
147 | spin_unlock(&journal->j_state_lock); | |
e3df1898 | 148 | del_timer_sync(&journal->j_commit_timer); |
1da177e4 LT |
149 | journal_commit_transaction(journal); |
150 | spin_lock(&journal->j_state_lock); | |
151 | goto loop; | |
152 | } | |
153 | ||
154 | wake_up(&journal->j_wait_done_commit); | |
3e1d1d28 | 155 | if (freezing(current)) { |
1da177e4 LT |
156 | /* |
157 | * The simpler the better. Flushing journal isn't a | |
158 | * good idea, because that depends on threads that may | |
159 | * be already stopped. | |
160 | */ | |
161 | jbd_debug(1, "Now suspending kjournald\n"); | |
162 | spin_unlock(&journal->j_state_lock); | |
3e1d1d28 | 163 | refrigerator(); |
1da177e4 LT |
164 | spin_lock(&journal->j_state_lock); |
165 | } else { | |
166 | /* | |
167 | * We assume on resume that commits are already there, | |
168 | * so we don't sleep | |
169 | */ | |
170 | DEFINE_WAIT(wait); | |
171 | int should_sleep = 1; | |
172 | ||
173 | prepare_to_wait(&journal->j_wait_commit, &wait, | |
174 | TASK_INTERRUPTIBLE); | |
175 | if (journal->j_commit_sequence != journal->j_commit_request) | |
176 | should_sleep = 0; | |
177 | transaction = journal->j_running_transaction; | |
178 | if (transaction && time_after_eq(jiffies, | |
179 | transaction->t_expires)) | |
180 | should_sleep = 0; | |
cbf0d27a MF |
181 | if (journal->j_flags & JFS_UNMOUNT) |
182 | should_sleep = 0; | |
1da177e4 LT |
183 | if (should_sleep) { |
184 | spin_unlock(&journal->j_state_lock); | |
185 | schedule(); | |
186 | spin_lock(&journal->j_state_lock); | |
187 | } | |
188 | finish_wait(&journal->j_wait_commit, &wait); | |
189 | } | |
190 | ||
191 | jbd_debug(1, "kjournald wakes\n"); | |
192 | ||
193 | /* | |
194 | * Were we woken up by a commit wakeup event? | |
195 | */ | |
196 | transaction = journal->j_running_transaction; | |
197 | if (transaction && time_after_eq(jiffies, transaction->t_expires)) { | |
198 | journal->j_commit_request = transaction->t_tid; | |
199 | jbd_debug(1, "woke because of timeout\n"); | |
200 | } | |
201 | goto loop; | |
202 | ||
203 | end_loop: | |
204 | spin_unlock(&journal->j_state_lock); | |
e3df1898 | 205 | del_timer_sync(&journal->j_commit_timer); |
1da177e4 LT |
206 | journal->j_task = NULL; |
207 | wake_up(&journal->j_wait_done_commit); | |
208 | jbd_debug(1, "Journal thread exiting.\n"); | |
209 | return 0; | |
210 | } | |
211 | ||
212 | static void journal_start_thread(journal_t *journal) | |
213 | { | |
214 | kernel_thread(kjournald, journal, CLONE_VM|CLONE_FS|CLONE_FILES); | |
215 | wait_event(journal->j_wait_done_commit, journal->j_task != 0); | |
216 | } | |
217 | ||
218 | static void journal_kill_thread(journal_t *journal) | |
219 | { | |
220 | spin_lock(&journal->j_state_lock); | |
221 | journal->j_flags |= JFS_UNMOUNT; | |
222 | ||
223 | while (journal->j_task) { | |
224 | wake_up(&journal->j_wait_commit); | |
225 | spin_unlock(&journal->j_state_lock); | |
226 | wait_event(journal->j_wait_done_commit, journal->j_task == 0); | |
227 | spin_lock(&journal->j_state_lock); | |
228 | } | |
229 | spin_unlock(&journal->j_state_lock); | |
230 | } | |
231 | ||
232 | /* | |
233 | * journal_write_metadata_buffer: write a metadata buffer to the journal. | |
234 | * | |
235 | * Writes a metadata buffer to a given disk block. The actual IO is not | |
236 | * performed but a new buffer_head is constructed which labels the data | |
237 | * to be written with the correct destination disk block. | |
238 | * | |
239 | * Any magic-number escaping which needs to be done will cause a | |
240 | * copy-out here. If the buffer happens to start with the | |
241 | * JFS_MAGIC_NUMBER, then we can't write it to the log directly: the | |
242 | * magic number is only written to the log for descripter blocks. In | |
243 | * this case, we copy the data and replace the first word with 0, and we | |
244 | * return a result code which indicates that this buffer needs to be | |
245 | * marked as an escaped buffer in the corresponding log descriptor | |
246 | * block. The missing word can then be restored when the block is read | |
247 | * during recovery. | |
248 | * | |
249 | * If the source buffer has already been modified by a new transaction | |
250 | * since we took the last commit snapshot, we use the frozen copy of | |
251 | * that data for IO. If we end up using the existing buffer_head's data | |
252 | * for the write, then we *have* to lock the buffer to prevent anyone | |
253 | * else from using and possibly modifying it while the IO is in | |
254 | * progress. | |
255 | * | |
256 | * The function returns a pointer to the buffer_heads to be used for IO. | |
257 | * | |
258 | * We assume that the journal has already been locked in this function. | |
259 | * | |
260 | * Return value: | |
261 | * <0: Error | |
262 | * >=0: Finished OK | |
263 | * | |
264 | * On success: | |
265 | * Bit 0 set == escape performed on the data | |
266 | * Bit 1 set == buffer copy-out performed (kfree the data after IO) | |
267 | */ | |
268 | ||
269 | int journal_write_metadata_buffer(transaction_t *transaction, | |
270 | struct journal_head *jh_in, | |
271 | struct journal_head **jh_out, | |
272 | int blocknr) | |
273 | { | |
274 | int need_copy_out = 0; | |
275 | int done_copy_out = 0; | |
276 | int do_escape = 0; | |
277 | char *mapped_data; | |
278 | struct buffer_head *new_bh; | |
279 | struct journal_head *new_jh; | |
280 | struct page *new_page; | |
281 | unsigned int new_offset; | |
282 | struct buffer_head *bh_in = jh2bh(jh_in); | |
283 | ||
284 | /* | |
285 | * The buffer really shouldn't be locked: only the current committing | |
286 | * transaction is allowed to write it, so nobody else is allowed | |
287 | * to do any IO. | |
288 | * | |
289 | * akpm: except if we're journalling data, and write() output is | |
290 | * also part of a shared mapping, and another thread has | |
291 | * decided to launch a writepage() against this buffer. | |
292 | */ | |
293 | J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in)); | |
294 | ||
295 | new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL); | |
296 | ||
297 | /* | |
298 | * If a new transaction has already done a buffer copy-out, then | |
299 | * we use that version of the data for the commit. | |
300 | */ | |
301 | jbd_lock_bh_state(bh_in); | |
302 | repeat: | |
303 | if (jh_in->b_frozen_data) { | |
304 | done_copy_out = 1; | |
305 | new_page = virt_to_page(jh_in->b_frozen_data); | |
306 | new_offset = offset_in_page(jh_in->b_frozen_data); | |
307 | } else { | |
308 | new_page = jh2bh(jh_in)->b_page; | |
309 | new_offset = offset_in_page(jh2bh(jh_in)->b_data); | |
310 | } | |
311 | ||
312 | mapped_data = kmap_atomic(new_page, KM_USER0); | |
313 | /* | |
314 | * Check for escaping | |
315 | */ | |
316 | if (*((__be32 *)(mapped_data + new_offset)) == | |
317 | cpu_to_be32(JFS_MAGIC_NUMBER)) { | |
318 | need_copy_out = 1; | |
319 | do_escape = 1; | |
320 | } | |
321 | kunmap_atomic(mapped_data, KM_USER0); | |
322 | ||
323 | /* | |
324 | * Do we need to do a data copy? | |
325 | */ | |
326 | if (need_copy_out && !done_copy_out) { | |
327 | char *tmp; | |
328 | ||
329 | jbd_unlock_bh_state(bh_in); | |
330 | tmp = jbd_rep_kmalloc(bh_in->b_size, GFP_NOFS); | |
331 | jbd_lock_bh_state(bh_in); | |
332 | if (jh_in->b_frozen_data) { | |
333 | kfree(tmp); | |
334 | goto repeat; | |
335 | } | |
336 | ||
337 | jh_in->b_frozen_data = tmp; | |
338 | mapped_data = kmap_atomic(new_page, KM_USER0); | |
339 | memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size); | |
340 | kunmap_atomic(mapped_data, KM_USER0); | |
341 | ||
342 | new_page = virt_to_page(tmp); | |
343 | new_offset = offset_in_page(tmp); | |
344 | done_copy_out = 1; | |
345 | } | |
346 | ||
347 | /* | |
348 | * Did we need to do an escaping? Now we've done all the | |
349 | * copying, we can finally do so. | |
350 | */ | |
351 | if (do_escape) { | |
352 | mapped_data = kmap_atomic(new_page, KM_USER0); | |
353 | *((unsigned int *)(mapped_data + new_offset)) = 0; | |
354 | kunmap_atomic(mapped_data, KM_USER0); | |
355 | } | |
356 | ||
357 | /* keep subsequent assertions sane */ | |
358 | new_bh->b_state = 0; | |
359 | init_buffer(new_bh, NULL, NULL); | |
360 | atomic_set(&new_bh->b_count, 1); | |
361 | jbd_unlock_bh_state(bh_in); | |
362 | ||
363 | new_jh = journal_add_journal_head(new_bh); /* This sleeps */ | |
364 | ||
365 | set_bh_page(new_bh, new_page, new_offset); | |
366 | new_jh->b_transaction = NULL; | |
367 | new_bh->b_size = jh2bh(jh_in)->b_size; | |
368 | new_bh->b_bdev = transaction->t_journal->j_dev; | |
369 | new_bh->b_blocknr = blocknr; | |
370 | set_buffer_mapped(new_bh); | |
371 | set_buffer_dirty(new_bh); | |
372 | ||
373 | *jh_out = new_jh; | |
374 | ||
375 | /* | |
376 | * The to-be-written buffer needs to get moved to the io queue, | |
377 | * and the original buffer whose contents we are shadowing or | |
378 | * copying is moved to the transaction's shadow queue. | |
379 | */ | |
380 | JBUFFER_TRACE(jh_in, "file as BJ_Shadow"); | |
381 | journal_file_buffer(jh_in, transaction, BJ_Shadow); | |
382 | JBUFFER_TRACE(new_jh, "file as BJ_IO"); | |
383 | journal_file_buffer(new_jh, transaction, BJ_IO); | |
384 | ||
385 | return do_escape | (done_copy_out << 1); | |
386 | } | |
387 | ||
388 | /* | |
389 | * Allocation code for the journal file. Manage the space left in the | |
390 | * journal, so that we can begin checkpointing when appropriate. | |
391 | */ | |
392 | ||
393 | /* | |
394 | * __log_space_left: Return the number of free blocks left in the journal. | |
395 | * | |
396 | * Called with the journal already locked. | |
397 | * | |
398 | * Called under j_state_lock | |
399 | */ | |
400 | ||
401 | int __log_space_left(journal_t *journal) | |
402 | { | |
403 | int left = journal->j_free; | |
404 | ||
405 | assert_spin_locked(&journal->j_state_lock); | |
406 | ||
407 | /* | |
408 | * Be pessimistic here about the number of those free blocks which | |
409 | * might be required for log descriptor control blocks. | |
410 | */ | |
411 | ||
412 | #define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */ | |
413 | ||
414 | left -= MIN_LOG_RESERVED_BLOCKS; | |
415 | ||
416 | if (left <= 0) | |
417 | return 0; | |
418 | left -= (left >> 3); | |
419 | return left; | |
420 | } | |
421 | ||
422 | /* | |
423 | * Called under j_state_lock. Returns true if a transaction was started. | |
424 | */ | |
425 | int __log_start_commit(journal_t *journal, tid_t target) | |
426 | { | |
427 | /* | |
428 | * Are we already doing a recent enough commit? | |
429 | */ | |
430 | if (!tid_geq(journal->j_commit_request, target)) { | |
431 | /* | |
432 | * We want a new commit: OK, mark the request and wakup the | |
433 | * commit thread. We do _not_ do the commit ourselves. | |
434 | */ | |
435 | ||
436 | journal->j_commit_request = target; | |
437 | jbd_debug(1, "JBD: requesting commit %d/%d\n", | |
438 | journal->j_commit_request, | |
439 | journal->j_commit_sequence); | |
440 | wake_up(&journal->j_wait_commit); | |
441 | return 1; | |
442 | } | |
443 | return 0; | |
444 | } | |
445 | ||
446 | int log_start_commit(journal_t *journal, tid_t tid) | |
447 | { | |
448 | int ret; | |
449 | ||
450 | spin_lock(&journal->j_state_lock); | |
451 | ret = __log_start_commit(journal, tid); | |
452 | spin_unlock(&journal->j_state_lock); | |
453 | return ret; | |
454 | } | |
455 | ||
456 | /* | |
457 | * Force and wait upon a commit if the calling process is not within | |
458 | * transaction. This is used for forcing out undo-protected data which contains | |
459 | * bitmaps, when the fs is running out of space. | |
460 | * | |
461 | * We can only force the running transaction if we don't have an active handle; | |
462 | * otherwise, we will deadlock. | |
463 | * | |
464 | * Returns true if a transaction was started. | |
465 | */ | |
466 | int journal_force_commit_nested(journal_t *journal) | |
467 | { | |
468 | transaction_t *transaction = NULL; | |
469 | tid_t tid; | |
470 | ||
471 | spin_lock(&journal->j_state_lock); | |
472 | if (journal->j_running_transaction && !current->journal_info) { | |
473 | transaction = journal->j_running_transaction; | |
474 | __log_start_commit(journal, transaction->t_tid); | |
475 | } else if (journal->j_committing_transaction) | |
476 | transaction = journal->j_committing_transaction; | |
477 | ||
478 | if (!transaction) { | |
479 | spin_unlock(&journal->j_state_lock); | |
480 | return 0; /* Nothing to retry */ | |
481 | } | |
482 | ||
483 | tid = transaction->t_tid; | |
484 | spin_unlock(&journal->j_state_lock); | |
485 | log_wait_commit(journal, tid); | |
486 | return 1; | |
487 | } | |
488 | ||
489 | /* | |
490 | * Start a commit of the current running transaction (if any). Returns true | |
491 | * if a transaction was started, and fills its tid in at *ptid | |
492 | */ | |
493 | int journal_start_commit(journal_t *journal, tid_t *ptid) | |
494 | { | |
495 | int ret = 0; | |
496 | ||
497 | spin_lock(&journal->j_state_lock); | |
498 | if (journal->j_running_transaction) { | |
499 | tid_t tid = journal->j_running_transaction->t_tid; | |
500 | ||
501 | ret = __log_start_commit(journal, tid); | |
502 | if (ret && ptid) | |
503 | *ptid = tid; | |
504 | } else if (journal->j_committing_transaction && ptid) { | |
505 | /* | |
506 | * If ext3_write_super() recently started a commit, then we | |
507 | * have to wait for completion of that transaction | |
508 | */ | |
509 | *ptid = journal->j_committing_transaction->t_tid; | |
510 | ret = 1; | |
511 | } | |
512 | spin_unlock(&journal->j_state_lock); | |
513 | return ret; | |
514 | } | |
515 | ||
516 | /* | |
517 | * Wait for a specified commit to complete. | |
518 | * The caller may not hold the journal lock. | |
519 | */ | |
520 | int log_wait_commit(journal_t *journal, tid_t tid) | |
521 | { | |
522 | int err = 0; | |
523 | ||
524 | #ifdef CONFIG_JBD_DEBUG | |
525 | spin_lock(&journal->j_state_lock); | |
526 | if (!tid_geq(journal->j_commit_request, tid)) { | |
527 | printk(KERN_EMERG | |
528 | "%s: error: j_commit_request=%d, tid=%d\n", | |
529 | __FUNCTION__, journal->j_commit_request, tid); | |
530 | } | |
531 | spin_unlock(&journal->j_state_lock); | |
532 | #endif | |
533 | spin_lock(&journal->j_state_lock); | |
534 | while (tid_gt(tid, journal->j_commit_sequence)) { | |
535 | jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n", | |
536 | tid, journal->j_commit_sequence); | |
537 | wake_up(&journal->j_wait_commit); | |
538 | spin_unlock(&journal->j_state_lock); | |
539 | wait_event(journal->j_wait_done_commit, | |
540 | !tid_gt(tid, journal->j_commit_sequence)); | |
541 | spin_lock(&journal->j_state_lock); | |
542 | } | |
543 | spin_unlock(&journal->j_state_lock); | |
544 | ||
545 | if (unlikely(is_journal_aborted(journal))) { | |
546 | printk(KERN_EMERG "journal commit I/O error\n"); | |
547 | err = -EIO; | |
548 | } | |
549 | return err; | |
550 | } | |
551 | ||
552 | /* | |
553 | * Log buffer allocation routines: | |
554 | */ | |
555 | ||
556 | int journal_next_log_block(journal_t *journal, unsigned long *retp) | |
557 | { | |
558 | unsigned long blocknr; | |
559 | ||
560 | spin_lock(&journal->j_state_lock); | |
561 | J_ASSERT(journal->j_free > 1); | |
562 | ||
563 | blocknr = journal->j_head; | |
564 | journal->j_head++; | |
565 | journal->j_free--; | |
566 | if (journal->j_head == journal->j_last) | |
567 | journal->j_head = journal->j_first; | |
568 | spin_unlock(&journal->j_state_lock); | |
569 | return journal_bmap(journal, blocknr, retp); | |
570 | } | |
571 | ||
572 | /* | |
573 | * Conversion of logical to physical block numbers for the journal | |
574 | * | |
575 | * On external journals the journal blocks are identity-mapped, so | |
576 | * this is a no-op. If needed, we can use j_blk_offset - everything is | |
577 | * ready. | |
578 | */ | |
579 | int journal_bmap(journal_t *journal, unsigned long blocknr, | |
580 | unsigned long *retp) | |
581 | { | |
582 | int err = 0; | |
583 | unsigned long ret; | |
584 | ||
585 | if (journal->j_inode) { | |
586 | ret = bmap(journal->j_inode, blocknr); | |
587 | if (ret) | |
588 | *retp = ret; | |
589 | else { | |
590 | char b[BDEVNAME_SIZE]; | |
591 | ||
592 | printk(KERN_ALERT "%s: journal block not found " | |
593 | "at offset %lu on %s\n", | |
594 | __FUNCTION__, | |
595 | blocknr, | |
596 | bdevname(journal->j_dev, b)); | |
597 | err = -EIO; | |
598 | __journal_abort_soft(journal, err); | |
599 | } | |
600 | } else { | |
601 | *retp = blocknr; /* +journal->j_blk_offset */ | |
602 | } | |
603 | return err; | |
604 | } | |
605 | ||
606 | /* | |
607 | * We play buffer_head aliasing tricks to write data/metadata blocks to | |
608 | * the journal without copying their contents, but for journal | |
609 | * descriptor blocks we do need to generate bona fide buffers. | |
610 | * | |
611 | * After the caller of journal_get_descriptor_buffer() has finished modifying | |
612 | * the buffer's contents they really should run flush_dcache_page(bh->b_page). | |
613 | * But we don't bother doing that, so there will be coherency problems with | |
614 | * mmaps of blockdevs which hold live JBD-controlled filesystems. | |
615 | */ | |
616 | struct journal_head *journal_get_descriptor_buffer(journal_t *journal) | |
617 | { | |
618 | struct buffer_head *bh; | |
619 | unsigned long blocknr; | |
620 | int err; | |
621 | ||
622 | err = journal_next_log_block(journal, &blocknr); | |
623 | ||
624 | if (err) | |
625 | return NULL; | |
626 | ||
627 | bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); | |
628 | lock_buffer(bh); | |
629 | memset(bh->b_data, 0, journal->j_blocksize); | |
630 | set_buffer_uptodate(bh); | |
631 | unlock_buffer(bh); | |
632 | BUFFER_TRACE(bh, "return this buffer"); | |
633 | return journal_add_journal_head(bh); | |
634 | } | |
635 | ||
636 | /* | |
637 | * Management for journal control blocks: functions to create and | |
638 | * destroy journal_t structures, and to initialise and read existing | |
639 | * journal blocks from disk. */ | |
640 | ||
641 | /* First: create and setup a journal_t object in memory. We initialise | |
642 | * very few fields yet: that has to wait until we have created the | |
643 | * journal structures from from scratch, or loaded them from disk. */ | |
644 | ||
645 | static journal_t * journal_init_common (void) | |
646 | { | |
647 | journal_t *journal; | |
648 | int err; | |
649 | ||
650 | journal = jbd_kmalloc(sizeof(*journal), GFP_KERNEL); | |
651 | if (!journal) | |
652 | goto fail; | |
653 | memset(journal, 0, sizeof(*journal)); | |
654 | ||
655 | init_waitqueue_head(&journal->j_wait_transaction_locked); | |
656 | init_waitqueue_head(&journal->j_wait_logspace); | |
657 | init_waitqueue_head(&journal->j_wait_done_commit); | |
658 | init_waitqueue_head(&journal->j_wait_checkpoint); | |
659 | init_waitqueue_head(&journal->j_wait_commit); | |
660 | init_waitqueue_head(&journal->j_wait_updates); | |
2c68ee75 AV |
661 | mutex_init(&journal->j_barrier); |
662 | mutex_init(&journal->j_checkpoint_mutex); | |
1da177e4 LT |
663 | spin_lock_init(&journal->j_revoke_lock); |
664 | spin_lock_init(&journal->j_list_lock); | |
665 | spin_lock_init(&journal->j_state_lock); | |
666 | ||
667 | journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE); | |
668 | ||
669 | /* The journal is marked for error until we succeed with recovery! */ | |
670 | journal->j_flags = JFS_ABORT; | |
671 | ||
672 | /* Set up a default-sized revoke table for the new mount. */ | |
673 | err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH); | |
674 | if (err) { | |
675 | kfree(journal); | |
676 | goto fail; | |
677 | } | |
678 | return journal; | |
679 | fail: | |
680 | return NULL; | |
681 | } | |
682 | ||
683 | /* journal_init_dev and journal_init_inode: | |
684 | * | |
685 | * Create a journal structure assigned some fixed set of disk blocks to | |
686 | * the journal. We don't actually touch those disk blocks yet, but we | |
687 | * need to set up all of the mapping information to tell the journaling | |
688 | * system where the journal blocks are. | |
689 | * | |
690 | */ | |
691 | ||
692 | /** | |
693 | * journal_t * journal_init_dev() - creates an initialises a journal structure | |
694 | * @bdev: Block device on which to create the journal | |
695 | * @fs_dev: Device which hold journalled filesystem for this journal. | |
696 | * @start: Block nr Start of journal. | |
697 | * @len: Lenght of the journal in blocks. | |
698 | * @blocksize: blocksize of journalling device | |
699 | * @returns: a newly created journal_t * | |
700 | * | |
701 | * journal_init_dev creates a journal which maps a fixed contiguous | |
702 | * range of blocks on an arbitrary block device. | |
703 | * | |
704 | */ | |
705 | journal_t * journal_init_dev(struct block_device *bdev, | |
706 | struct block_device *fs_dev, | |
707 | int start, int len, int blocksize) | |
708 | { | |
709 | journal_t *journal = journal_init_common(); | |
710 | struct buffer_head *bh; | |
711 | int n; | |
712 | ||
713 | if (!journal) | |
714 | return NULL; | |
715 | ||
716 | journal->j_dev = bdev; | |
717 | journal->j_fs_dev = fs_dev; | |
718 | journal->j_blk_offset = start; | |
719 | journal->j_maxlen = len; | |
720 | journal->j_blocksize = blocksize; | |
721 | ||
722 | bh = __getblk(journal->j_dev, start, journal->j_blocksize); | |
723 | J_ASSERT(bh != NULL); | |
724 | journal->j_sb_buffer = bh; | |
725 | journal->j_superblock = (journal_superblock_t *)bh->b_data; | |
726 | ||
727 | /* journal descriptor can store up to n blocks -bzzz */ | |
728 | n = journal->j_blocksize / sizeof(journal_block_tag_t); | |
729 | journal->j_wbufsize = n; | |
730 | journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); | |
731 | if (!journal->j_wbuf) { | |
732 | printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n", | |
733 | __FUNCTION__); | |
734 | kfree(journal); | |
735 | journal = NULL; | |
736 | } | |
737 | ||
738 | return journal; | |
739 | } | |
740 | ||
741 | /** | |
742 | * journal_t * journal_init_inode () - creates a journal which maps to a inode. | |
743 | * @inode: An inode to create the journal in | |
744 | * | |
745 | * journal_init_inode creates a journal which maps an on-disk inode as | |
746 | * the journal. The inode must exist already, must support bmap() and | |
747 | * must have all data blocks preallocated. | |
748 | */ | |
749 | journal_t * journal_init_inode (struct inode *inode) | |
750 | { | |
751 | struct buffer_head *bh; | |
752 | journal_t *journal = journal_init_common(); | |
753 | int err; | |
754 | int n; | |
755 | unsigned long blocknr; | |
756 | ||
757 | if (!journal) | |
758 | return NULL; | |
759 | ||
760 | journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev; | |
761 | journal->j_inode = inode; | |
762 | jbd_debug(1, | |
763 | "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n", | |
764 | journal, inode->i_sb->s_id, inode->i_ino, | |
765 | (long long) inode->i_size, | |
766 | inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize); | |
767 | ||
768 | journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits; | |
769 | journal->j_blocksize = inode->i_sb->s_blocksize; | |
770 | ||
771 | /* journal descriptor can store up to n blocks -bzzz */ | |
772 | n = journal->j_blocksize / sizeof(journal_block_tag_t); | |
773 | journal->j_wbufsize = n; | |
774 | journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); | |
775 | if (!journal->j_wbuf) { | |
776 | printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n", | |
777 | __FUNCTION__); | |
778 | kfree(journal); | |
779 | return NULL; | |
780 | } | |
781 | ||
782 | err = journal_bmap(journal, 0, &blocknr); | |
783 | /* If that failed, give up */ | |
784 | if (err) { | |
785 | printk(KERN_ERR "%s: Cannnot locate journal superblock\n", | |
786 | __FUNCTION__); | |
787 | kfree(journal); | |
788 | return NULL; | |
789 | } | |
790 | ||
791 | bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); | |
792 | J_ASSERT(bh != NULL); | |
793 | journal->j_sb_buffer = bh; | |
794 | journal->j_superblock = (journal_superblock_t *)bh->b_data; | |
795 | ||
796 | return journal; | |
797 | } | |
798 | ||
799 | /* | |
800 | * If the journal init or create aborts, we need to mark the journal | |
801 | * superblock as being NULL to prevent the journal destroy from writing | |
802 | * back a bogus superblock. | |
803 | */ | |
804 | static void journal_fail_superblock (journal_t *journal) | |
805 | { | |
806 | struct buffer_head *bh = journal->j_sb_buffer; | |
807 | brelse(bh); | |
808 | journal->j_sb_buffer = NULL; | |
809 | } | |
810 | ||
811 | /* | |
812 | * Given a journal_t structure, initialise the various fields for | |
813 | * startup of a new journaling session. We use this both when creating | |
814 | * a journal, and after recovering an old journal to reset it for | |
815 | * subsequent use. | |
816 | */ | |
817 | ||
818 | static int journal_reset(journal_t *journal) | |
819 | { | |
820 | journal_superblock_t *sb = journal->j_superblock; | |
821 | unsigned int first, last; | |
822 | ||
823 | first = be32_to_cpu(sb->s_first); | |
824 | last = be32_to_cpu(sb->s_maxlen); | |
825 | ||
826 | journal->j_first = first; | |
827 | journal->j_last = last; | |
828 | ||
829 | journal->j_head = first; | |
830 | journal->j_tail = first; | |
831 | journal->j_free = last - first; | |
832 | ||
833 | journal->j_tail_sequence = journal->j_transaction_sequence; | |
834 | journal->j_commit_sequence = journal->j_transaction_sequence - 1; | |
835 | journal->j_commit_request = journal->j_commit_sequence; | |
836 | ||
837 | journal->j_max_transaction_buffers = journal->j_maxlen / 4; | |
838 | ||
839 | /* Add the dynamic fields and write it to disk. */ | |
840 | journal_update_superblock(journal, 1); | |
841 | journal_start_thread(journal); | |
842 | return 0; | |
843 | } | |
844 | ||
845 | /** | |
846 | * int journal_create() - Initialise the new journal file | |
847 | * @journal: Journal to create. This structure must have been initialised | |
848 | * | |
849 | * Given a journal_t structure which tells us which disk blocks we can | |
850 | * use, create a new journal superblock and initialise all of the | |
851 | * journal fields from scratch. | |
852 | **/ | |
853 | int journal_create(journal_t *journal) | |
854 | { | |
855 | unsigned long blocknr; | |
856 | struct buffer_head *bh; | |
857 | journal_superblock_t *sb; | |
858 | int i, err; | |
859 | ||
860 | if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) { | |
861 | printk (KERN_ERR "Journal length (%d blocks) too short.\n", | |
862 | journal->j_maxlen); | |
863 | journal_fail_superblock(journal); | |
864 | return -EINVAL; | |
865 | } | |
866 | ||
867 | if (journal->j_inode == NULL) { | |
868 | /* | |
869 | * We don't know what block to start at! | |
870 | */ | |
871 | printk(KERN_EMERG | |
872 | "%s: creation of journal on external device!\n", | |
873 | __FUNCTION__); | |
874 | BUG(); | |
875 | } | |
876 | ||
877 | /* Zero out the entire journal on disk. We cannot afford to | |
878 | have any blocks on disk beginning with JFS_MAGIC_NUMBER. */ | |
879 | jbd_debug(1, "JBD: Zeroing out journal blocks...\n"); | |
880 | for (i = 0; i < journal->j_maxlen; i++) { | |
881 | err = journal_bmap(journal, i, &blocknr); | |
882 | if (err) | |
883 | return err; | |
884 | bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); | |
885 | lock_buffer(bh); | |
886 | memset (bh->b_data, 0, journal->j_blocksize); | |
887 | BUFFER_TRACE(bh, "marking dirty"); | |
888 | mark_buffer_dirty(bh); | |
889 | BUFFER_TRACE(bh, "marking uptodate"); | |
890 | set_buffer_uptodate(bh); | |
891 | unlock_buffer(bh); | |
892 | __brelse(bh); | |
893 | } | |
894 | ||
895 | sync_blockdev(journal->j_dev); | |
896 | jbd_debug(1, "JBD: journal cleared.\n"); | |
897 | ||
898 | /* OK, fill in the initial static fields in the new superblock */ | |
899 | sb = journal->j_superblock; | |
900 | ||
901 | sb->s_header.h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
902 | sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2); | |
903 | ||
904 | sb->s_blocksize = cpu_to_be32(journal->j_blocksize); | |
905 | sb->s_maxlen = cpu_to_be32(journal->j_maxlen); | |
906 | sb->s_first = cpu_to_be32(1); | |
907 | ||
908 | journal->j_transaction_sequence = 1; | |
909 | ||
910 | journal->j_flags &= ~JFS_ABORT; | |
911 | journal->j_format_version = 2; | |
912 | ||
913 | return journal_reset(journal); | |
914 | } | |
915 | ||
916 | /** | |
917 | * void journal_update_superblock() - Update journal sb on disk. | |
918 | * @journal: The journal to update. | |
919 | * @wait: Set to '0' if you don't want to wait for IO completion. | |
920 | * | |
921 | * Update a journal's dynamic superblock fields and write it to disk, | |
922 | * optionally waiting for the IO to complete. | |
923 | */ | |
924 | void journal_update_superblock(journal_t *journal, int wait) | |
925 | { | |
926 | journal_superblock_t *sb = journal->j_superblock; | |
927 | struct buffer_head *bh = journal->j_sb_buffer; | |
928 | ||
929 | /* | |
930 | * As a special case, if the on-disk copy is already marked as needing | |
931 | * no recovery (s_start == 0) and there are no outstanding transactions | |
932 | * in the filesystem, then we can safely defer the superblock update | |
933 | * until the next commit by setting JFS_FLUSHED. This avoids | |
934 | * attempting a write to a potential-readonly device. | |
935 | */ | |
936 | if (sb->s_start == 0 && journal->j_tail_sequence == | |
937 | journal->j_transaction_sequence) { | |
938 | jbd_debug(1,"JBD: Skipping superblock update on recovered sb " | |
939 | "(start %ld, seq %d, errno %d)\n", | |
940 | journal->j_tail, journal->j_tail_sequence, | |
941 | journal->j_errno); | |
942 | goto out; | |
943 | } | |
944 | ||
945 | spin_lock(&journal->j_state_lock); | |
946 | jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n", | |
947 | journal->j_tail, journal->j_tail_sequence, journal->j_errno); | |
948 | ||
949 | sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); | |
950 | sb->s_start = cpu_to_be32(journal->j_tail); | |
951 | sb->s_errno = cpu_to_be32(journal->j_errno); | |
952 | spin_unlock(&journal->j_state_lock); | |
953 | ||
954 | BUFFER_TRACE(bh, "marking dirty"); | |
955 | mark_buffer_dirty(bh); | |
956 | if (wait) | |
957 | sync_dirty_buffer(bh); | |
958 | else | |
26707699 | 959 | ll_rw_block(SWRITE, 1, &bh); |
1da177e4 LT |
960 | |
961 | out: | |
962 | /* If we have just flushed the log (by marking s_start==0), then | |
963 | * any future commit will have to be careful to update the | |
964 | * superblock again to re-record the true start of the log. */ | |
965 | ||
966 | spin_lock(&journal->j_state_lock); | |
967 | if (sb->s_start) | |
968 | journal->j_flags &= ~JFS_FLUSHED; | |
969 | else | |
970 | journal->j_flags |= JFS_FLUSHED; | |
971 | spin_unlock(&journal->j_state_lock); | |
972 | } | |
973 | ||
974 | /* | |
975 | * Read the superblock for a given journal, performing initial | |
976 | * validation of the format. | |
977 | */ | |
978 | ||
979 | static int journal_get_superblock(journal_t *journal) | |
980 | { | |
981 | struct buffer_head *bh; | |
982 | journal_superblock_t *sb; | |
983 | int err = -EIO; | |
984 | ||
985 | bh = journal->j_sb_buffer; | |
986 | ||
987 | J_ASSERT(bh != NULL); | |
988 | if (!buffer_uptodate(bh)) { | |
989 | ll_rw_block(READ, 1, &bh); | |
990 | wait_on_buffer(bh); | |
991 | if (!buffer_uptodate(bh)) { | |
992 | printk (KERN_ERR | |
993 | "JBD: IO error reading journal superblock\n"); | |
994 | goto out; | |
995 | } | |
996 | } | |
997 | ||
998 | sb = journal->j_superblock; | |
999 | ||
1000 | err = -EINVAL; | |
1001 | ||
1002 | if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) || | |
1003 | sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) { | |
1004 | printk(KERN_WARNING "JBD: no valid journal superblock found\n"); | |
1005 | goto out; | |
1006 | } | |
1007 | ||
1008 | switch(be32_to_cpu(sb->s_header.h_blocktype)) { | |
1009 | case JFS_SUPERBLOCK_V1: | |
1010 | journal->j_format_version = 1; | |
1011 | break; | |
1012 | case JFS_SUPERBLOCK_V2: | |
1013 | journal->j_format_version = 2; | |
1014 | break; | |
1015 | default: | |
1016 | printk(KERN_WARNING "JBD: unrecognised superblock format ID\n"); | |
1017 | goto out; | |
1018 | } | |
1019 | ||
1020 | if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen) | |
1021 | journal->j_maxlen = be32_to_cpu(sb->s_maxlen); | |
1022 | else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) { | |
1023 | printk (KERN_WARNING "JBD: journal file too short\n"); | |
1024 | goto out; | |
1025 | } | |
1026 | ||
1027 | return 0; | |
1028 | ||
1029 | out: | |
1030 | journal_fail_superblock(journal); | |
1031 | return err; | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * Load the on-disk journal superblock and read the key fields into the | |
1036 | * journal_t. | |
1037 | */ | |
1038 | ||
1039 | static int load_superblock(journal_t *journal) | |
1040 | { | |
1041 | int err; | |
1042 | journal_superblock_t *sb; | |
1043 | ||
1044 | err = journal_get_superblock(journal); | |
1045 | if (err) | |
1046 | return err; | |
1047 | ||
1048 | sb = journal->j_superblock; | |
1049 | ||
1050 | journal->j_tail_sequence = be32_to_cpu(sb->s_sequence); | |
1051 | journal->j_tail = be32_to_cpu(sb->s_start); | |
1052 | journal->j_first = be32_to_cpu(sb->s_first); | |
1053 | journal->j_last = be32_to_cpu(sb->s_maxlen); | |
1054 | journal->j_errno = be32_to_cpu(sb->s_errno); | |
1055 | ||
1056 | return 0; | |
1057 | } | |
1058 | ||
1059 | ||
1060 | /** | |
1061 | * int journal_load() - Read journal from disk. | |
1062 | * @journal: Journal to act on. | |
1063 | * | |
1064 | * Given a journal_t structure which tells us which disk blocks contain | |
1065 | * a journal, read the journal from disk to initialise the in-memory | |
1066 | * structures. | |
1067 | */ | |
1068 | int journal_load(journal_t *journal) | |
1069 | { | |
1070 | int err; | |
1071 | ||
1072 | err = load_superblock(journal); | |
1073 | if (err) | |
1074 | return err; | |
1075 | ||
1076 | /* If this is a V2 superblock, then we have to check the | |
1077 | * features flags on it. */ | |
1078 | ||
1079 | if (journal->j_format_version >= 2) { | |
1080 | journal_superblock_t *sb = journal->j_superblock; | |
1081 | ||
1082 | if ((sb->s_feature_ro_compat & | |
1083 | ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) || | |
1084 | (sb->s_feature_incompat & | |
1085 | ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) { | |
1086 | printk (KERN_WARNING | |
1087 | "JBD: Unrecognised features on journal\n"); | |
1088 | return -EINVAL; | |
1089 | } | |
1090 | } | |
1091 | ||
1092 | /* Let the recovery code check whether it needs to recover any | |
1093 | * data from the journal. */ | |
1094 | if (journal_recover(journal)) | |
1095 | goto recovery_error; | |
1096 | ||
1097 | /* OK, we've finished with the dynamic journal bits: | |
1098 | * reinitialise the dynamic contents of the superblock in memory | |
1099 | * and reset them on disk. */ | |
1100 | if (journal_reset(journal)) | |
1101 | goto recovery_error; | |
1102 | ||
1103 | journal->j_flags &= ~JFS_ABORT; | |
1104 | journal->j_flags |= JFS_LOADED; | |
1105 | return 0; | |
1106 | ||
1107 | recovery_error: | |
1108 | printk (KERN_WARNING "JBD: recovery failed\n"); | |
1109 | return -EIO; | |
1110 | } | |
1111 | ||
1112 | /** | |
1113 | * void journal_destroy() - Release a journal_t structure. | |
1114 | * @journal: Journal to act on. | |
1115 | * | |
1116 | * Release a journal_t structure once it is no longer in use by the | |
1117 | * journaled object. | |
1118 | */ | |
1119 | void journal_destroy(journal_t *journal) | |
1120 | { | |
1121 | /* Wait for the commit thread to wake up and die. */ | |
1122 | journal_kill_thread(journal); | |
1123 | ||
1124 | /* Force a final log commit */ | |
1125 | if (journal->j_running_transaction) | |
1126 | journal_commit_transaction(journal); | |
1127 | ||
1128 | /* Force any old transactions to disk */ | |
1129 | ||
1130 | /* Totally anal locking here... */ | |
1131 | spin_lock(&journal->j_list_lock); | |
1132 | while (journal->j_checkpoint_transactions != NULL) { | |
1133 | spin_unlock(&journal->j_list_lock); | |
1134 | log_do_checkpoint(journal); | |
1135 | spin_lock(&journal->j_list_lock); | |
1136 | } | |
1137 | ||
1138 | J_ASSERT(journal->j_running_transaction == NULL); | |
1139 | J_ASSERT(journal->j_committing_transaction == NULL); | |
1140 | J_ASSERT(journal->j_checkpoint_transactions == NULL); | |
1141 | spin_unlock(&journal->j_list_lock); | |
1142 | ||
1143 | /* We can now mark the journal as empty. */ | |
1144 | journal->j_tail = 0; | |
1145 | journal->j_tail_sequence = ++journal->j_transaction_sequence; | |
1146 | if (journal->j_sb_buffer) { | |
1147 | journal_update_superblock(journal, 1); | |
1148 | brelse(journal->j_sb_buffer); | |
1149 | } | |
1150 | ||
1151 | if (journal->j_inode) | |
1152 | iput(journal->j_inode); | |
1153 | if (journal->j_revoke) | |
1154 | journal_destroy_revoke(journal); | |
1155 | kfree(journal->j_wbuf); | |
1156 | kfree(journal); | |
1157 | } | |
1158 | ||
1159 | ||
1160 | /** | |
1161 | *int journal_check_used_features () - Check if features specified are used. | |
1162 | * @journal: Journal to check. | |
1163 | * @compat: bitmask of compatible features | |
1164 | * @ro: bitmask of features that force read-only mount | |
1165 | * @incompat: bitmask of incompatible features | |
1166 | * | |
1167 | * Check whether the journal uses all of a given set of | |
1168 | * features. Return true (non-zero) if it does. | |
1169 | **/ | |
1170 | ||
1171 | int journal_check_used_features (journal_t *journal, unsigned long compat, | |
1172 | unsigned long ro, unsigned long incompat) | |
1173 | { | |
1174 | journal_superblock_t *sb; | |
1175 | ||
1176 | if (!compat && !ro && !incompat) | |
1177 | return 1; | |
1178 | if (journal->j_format_version == 1) | |
1179 | return 0; | |
1180 | ||
1181 | sb = journal->j_superblock; | |
1182 | ||
1183 | if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) && | |
1184 | ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) && | |
1185 | ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat)) | |
1186 | return 1; | |
1187 | ||
1188 | return 0; | |
1189 | } | |
1190 | ||
1191 | /** | |
1192 | * int journal_check_available_features() - Check feature set in journalling layer | |
1193 | * @journal: Journal to check. | |
1194 | * @compat: bitmask of compatible features | |
1195 | * @ro: bitmask of features that force read-only mount | |
1196 | * @incompat: bitmask of incompatible features | |
1197 | * | |
1198 | * Check whether the journaling code supports the use of | |
1199 | * all of a given set of features on this journal. Return true | |
1200 | * (non-zero) if it can. */ | |
1201 | ||
1202 | int journal_check_available_features (journal_t *journal, unsigned long compat, | |
1203 | unsigned long ro, unsigned long incompat) | |
1204 | { | |
1205 | journal_superblock_t *sb; | |
1206 | ||
1207 | if (!compat && !ro && !incompat) | |
1208 | return 1; | |
1209 | ||
1210 | sb = journal->j_superblock; | |
1211 | ||
1212 | /* We can support any known requested features iff the | |
1213 | * superblock is in version 2. Otherwise we fail to support any | |
1214 | * extended sb features. */ | |
1215 | ||
1216 | if (journal->j_format_version != 2) | |
1217 | return 0; | |
1218 | ||
1219 | if ((compat & JFS_KNOWN_COMPAT_FEATURES) == compat && | |
1220 | (ro & JFS_KNOWN_ROCOMPAT_FEATURES) == ro && | |
1221 | (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat) | |
1222 | return 1; | |
1223 | ||
1224 | return 0; | |
1225 | } | |
1226 | ||
1227 | /** | |
1228 | * int journal_set_features () - Mark a given journal feature in the superblock | |
1229 | * @journal: Journal to act on. | |
1230 | * @compat: bitmask of compatible features | |
1231 | * @ro: bitmask of features that force read-only mount | |
1232 | * @incompat: bitmask of incompatible features | |
1233 | * | |
1234 | * Mark a given journal feature as present on the | |
1235 | * superblock. Returns true if the requested features could be set. | |
1236 | * | |
1237 | */ | |
1238 | ||
1239 | int journal_set_features (journal_t *journal, unsigned long compat, | |
1240 | unsigned long ro, unsigned long incompat) | |
1241 | { | |
1242 | journal_superblock_t *sb; | |
1243 | ||
1244 | if (journal_check_used_features(journal, compat, ro, incompat)) | |
1245 | return 1; | |
1246 | ||
1247 | if (!journal_check_available_features(journal, compat, ro, incompat)) | |
1248 | return 0; | |
1249 | ||
1250 | jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n", | |
1251 | compat, ro, incompat); | |
1252 | ||
1253 | sb = journal->j_superblock; | |
1254 | ||
1255 | sb->s_feature_compat |= cpu_to_be32(compat); | |
1256 | sb->s_feature_ro_compat |= cpu_to_be32(ro); | |
1257 | sb->s_feature_incompat |= cpu_to_be32(incompat); | |
1258 | ||
1259 | return 1; | |
1260 | } | |
1261 | ||
1262 | ||
1263 | /** | |
1264 | * int journal_update_format () - Update on-disk journal structure. | |
1265 | * @journal: Journal to act on. | |
1266 | * | |
1267 | * Given an initialised but unloaded journal struct, poke about in the | |
1268 | * on-disk structure to update it to the most recent supported version. | |
1269 | */ | |
1270 | int journal_update_format (journal_t *journal) | |
1271 | { | |
1272 | journal_superblock_t *sb; | |
1273 | int err; | |
1274 | ||
1275 | err = journal_get_superblock(journal); | |
1276 | if (err) | |
1277 | return err; | |
1278 | ||
1279 | sb = journal->j_superblock; | |
1280 | ||
1281 | switch (be32_to_cpu(sb->s_header.h_blocktype)) { | |
1282 | case JFS_SUPERBLOCK_V2: | |
1283 | return 0; | |
1284 | case JFS_SUPERBLOCK_V1: | |
1285 | return journal_convert_superblock_v1(journal, sb); | |
1286 | default: | |
1287 | break; | |
1288 | } | |
1289 | return -EINVAL; | |
1290 | } | |
1291 | ||
1292 | static int journal_convert_superblock_v1(journal_t *journal, | |
1293 | journal_superblock_t *sb) | |
1294 | { | |
1295 | int offset, blocksize; | |
1296 | struct buffer_head *bh; | |
1297 | ||
1298 | printk(KERN_WARNING | |
1299 | "JBD: Converting superblock from version 1 to 2.\n"); | |
1300 | ||
1301 | /* Pre-initialise new fields to zero */ | |
1302 | offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb); | |
1303 | blocksize = be32_to_cpu(sb->s_blocksize); | |
1304 | memset(&sb->s_feature_compat, 0, blocksize-offset); | |
1305 | ||
1306 | sb->s_nr_users = cpu_to_be32(1); | |
1307 | sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2); | |
1308 | journal->j_format_version = 2; | |
1309 | ||
1310 | bh = journal->j_sb_buffer; | |
1311 | BUFFER_TRACE(bh, "marking dirty"); | |
1312 | mark_buffer_dirty(bh); | |
1313 | sync_dirty_buffer(bh); | |
1314 | return 0; | |
1315 | } | |
1316 | ||
1317 | ||
1318 | /** | |
1319 | * int journal_flush () - Flush journal | |
1320 | * @journal: Journal to act on. | |
1321 | * | |
1322 | * Flush all data for a given journal to disk and empty the journal. | |
1323 | * Filesystems can use this when remounting readonly to ensure that | |
1324 | * recovery does not need to happen on remount. | |
1325 | */ | |
1326 | ||
1327 | int journal_flush(journal_t *journal) | |
1328 | { | |
1329 | int err = 0; | |
1330 | transaction_t *transaction = NULL; | |
1331 | unsigned long old_tail; | |
1332 | ||
1333 | spin_lock(&journal->j_state_lock); | |
1334 | ||
1335 | /* Force everything buffered to the log... */ | |
1336 | if (journal->j_running_transaction) { | |
1337 | transaction = journal->j_running_transaction; | |
1338 | __log_start_commit(journal, transaction->t_tid); | |
1339 | } else if (journal->j_committing_transaction) | |
1340 | transaction = journal->j_committing_transaction; | |
1341 | ||
1342 | /* Wait for the log commit to complete... */ | |
1343 | if (transaction) { | |
1344 | tid_t tid = transaction->t_tid; | |
1345 | ||
1346 | spin_unlock(&journal->j_state_lock); | |
1347 | log_wait_commit(journal, tid); | |
1348 | } else { | |
1349 | spin_unlock(&journal->j_state_lock); | |
1350 | } | |
1351 | ||
1352 | /* ...and flush everything in the log out to disk. */ | |
1353 | spin_lock(&journal->j_list_lock); | |
1354 | while (!err && journal->j_checkpoint_transactions != NULL) { | |
1355 | spin_unlock(&journal->j_list_lock); | |
1356 | err = log_do_checkpoint(journal); | |
1357 | spin_lock(&journal->j_list_lock); | |
1358 | } | |
1359 | spin_unlock(&journal->j_list_lock); | |
1360 | cleanup_journal_tail(journal); | |
1361 | ||
1362 | /* Finally, mark the journal as really needing no recovery. | |
1363 | * This sets s_start==0 in the underlying superblock, which is | |
1364 | * the magic code for a fully-recovered superblock. Any future | |
1365 | * commits of data to the journal will restore the current | |
1366 | * s_start value. */ | |
1367 | spin_lock(&journal->j_state_lock); | |
1368 | old_tail = journal->j_tail; | |
1369 | journal->j_tail = 0; | |
1370 | spin_unlock(&journal->j_state_lock); | |
1371 | journal_update_superblock(journal, 1); | |
1372 | spin_lock(&journal->j_state_lock); | |
1373 | journal->j_tail = old_tail; | |
1374 | ||
1375 | J_ASSERT(!journal->j_running_transaction); | |
1376 | J_ASSERT(!journal->j_committing_transaction); | |
1377 | J_ASSERT(!journal->j_checkpoint_transactions); | |
1378 | J_ASSERT(journal->j_head == journal->j_tail); | |
1379 | J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence); | |
1380 | spin_unlock(&journal->j_state_lock); | |
1381 | return err; | |
1382 | } | |
1383 | ||
1384 | /** | |
1385 | * int journal_wipe() - Wipe journal contents | |
1386 | * @journal: Journal to act on. | |
1387 | * @write: flag (see below) | |
1388 | * | |
1389 | * Wipe out all of the contents of a journal, safely. This will produce | |
1390 | * a warning if the journal contains any valid recovery information. | |
1391 | * Must be called between journal_init_*() and journal_load(). | |
1392 | * | |
1393 | * If 'write' is non-zero, then we wipe out the journal on disk; otherwise | |
1394 | * we merely suppress recovery. | |
1395 | */ | |
1396 | ||
1397 | int journal_wipe(journal_t *journal, int write) | |
1398 | { | |
1399 | journal_superblock_t *sb; | |
1400 | int err = 0; | |
1401 | ||
1402 | J_ASSERT (!(journal->j_flags & JFS_LOADED)); | |
1403 | ||
1404 | err = load_superblock(journal); | |
1405 | if (err) | |
1406 | return err; | |
1407 | ||
1408 | sb = journal->j_superblock; | |
1409 | ||
1410 | if (!journal->j_tail) | |
1411 | goto no_recovery; | |
1412 | ||
1413 | printk (KERN_WARNING "JBD: %s recovery information on journal\n", | |
1414 | write ? "Clearing" : "Ignoring"); | |
1415 | ||
1416 | err = journal_skip_recovery(journal); | |
1417 | if (write) | |
1418 | journal_update_superblock(journal, 1); | |
1419 | ||
1420 | no_recovery: | |
1421 | return err; | |
1422 | } | |
1423 | ||
1424 | /* | |
1425 | * journal_dev_name: format a character string to describe on what | |
1426 | * device this journal is present. | |
1427 | */ | |
1428 | ||
022a4a7b | 1429 | static const char *journal_dev_name(journal_t *journal, char *buffer) |
1da177e4 LT |
1430 | { |
1431 | struct block_device *bdev; | |
1432 | ||
1433 | if (journal->j_inode) | |
1434 | bdev = journal->j_inode->i_sb->s_bdev; | |
1435 | else | |
1436 | bdev = journal->j_dev; | |
1437 | ||
1438 | return bdevname(bdev, buffer); | |
1439 | } | |
1440 | ||
1441 | /* | |
1442 | * Journal abort has very specific semantics, which we describe | |
1443 | * for journal abort. | |
1444 | * | |
1445 | * Two internal function, which provide abort to te jbd layer | |
1446 | * itself are here. | |
1447 | */ | |
1448 | ||
1449 | /* | |
1450 | * Quick version for internal journal use (doesn't lock the journal). | |
1451 | * Aborts hard --- we mark the abort as occurred, but do _nothing_ else, | |
1452 | * and don't attempt to make any other journal updates. | |
1453 | */ | |
1454 | void __journal_abort_hard(journal_t *journal) | |
1455 | { | |
1456 | transaction_t *transaction; | |
1457 | char b[BDEVNAME_SIZE]; | |
1458 | ||
1459 | if (journal->j_flags & JFS_ABORT) | |
1460 | return; | |
1461 | ||
1462 | printk(KERN_ERR "Aborting journal on device %s.\n", | |
1463 | journal_dev_name(journal, b)); | |
1464 | ||
1465 | spin_lock(&journal->j_state_lock); | |
1466 | journal->j_flags |= JFS_ABORT; | |
1467 | transaction = journal->j_running_transaction; | |
1468 | if (transaction) | |
1469 | __log_start_commit(journal, transaction->t_tid); | |
1470 | spin_unlock(&journal->j_state_lock); | |
1471 | } | |
1472 | ||
1473 | /* Soft abort: record the abort error status in the journal superblock, | |
1474 | * but don't do any other IO. */ | |
022a4a7b | 1475 | static void __journal_abort_soft (journal_t *journal, int errno) |
1da177e4 LT |
1476 | { |
1477 | if (journal->j_flags & JFS_ABORT) | |
1478 | return; | |
1479 | ||
1480 | if (!journal->j_errno) | |
1481 | journal->j_errno = errno; | |
1482 | ||
1483 | __journal_abort_hard(journal); | |
1484 | ||
1485 | if (errno) | |
1486 | journal_update_superblock(journal, 1); | |
1487 | } | |
1488 | ||
1489 | /** | |
1490 | * void journal_abort () - Shutdown the journal immediately. | |
1491 | * @journal: the journal to shutdown. | |
1492 | * @errno: an error number to record in the journal indicating | |
1493 | * the reason for the shutdown. | |
1494 | * | |
1495 | * Perform a complete, immediate shutdown of the ENTIRE | |
1496 | * journal (not of a single transaction). This operation cannot be | |
1497 | * undone without closing and reopening the journal. | |
1498 | * | |
1499 | * The journal_abort function is intended to support higher level error | |
1500 | * recovery mechanisms such as the ext2/ext3 remount-readonly error | |
1501 | * mode. | |
1502 | * | |
1503 | * Journal abort has very specific semantics. Any existing dirty, | |
1504 | * unjournaled buffers in the main filesystem will still be written to | |
1505 | * disk by bdflush, but the journaling mechanism will be suspended | |
1506 | * immediately and no further transaction commits will be honoured. | |
1507 | * | |
1508 | * Any dirty, journaled buffers will be written back to disk without | |
1509 | * hitting the journal. Atomicity cannot be guaranteed on an aborted | |
1510 | * filesystem, but we _do_ attempt to leave as much data as possible | |
1511 | * behind for fsck to use for cleanup. | |
1512 | * | |
1513 | * Any attempt to get a new transaction handle on a journal which is in | |
1514 | * ABORT state will just result in an -EROFS error return. A | |
1515 | * journal_stop on an existing handle will return -EIO if we have | |
1516 | * entered abort state during the update. | |
1517 | * | |
1518 | * Recursive transactions are not disturbed by journal abort until the | |
1519 | * final journal_stop, which will receive the -EIO error. | |
1520 | * | |
1521 | * Finally, the journal_abort call allows the caller to supply an errno | |
1522 | * which will be recorded (if possible) in the journal superblock. This | |
1523 | * allows a client to record failure conditions in the middle of a | |
1524 | * transaction without having to complete the transaction to record the | |
1525 | * failure to disk. ext3_error, for example, now uses this | |
1526 | * functionality. | |
1527 | * | |
1528 | * Errors which originate from within the journaling layer will NOT | |
1529 | * supply an errno; a null errno implies that absolutely no further | |
1530 | * writes are done to the journal (unless there are any already in | |
1531 | * progress). | |
1532 | * | |
1533 | */ | |
1534 | ||
1535 | void journal_abort(journal_t *journal, int errno) | |
1536 | { | |
1537 | __journal_abort_soft(journal, errno); | |
1538 | } | |
1539 | ||
1540 | /** | |
1541 | * int journal_errno () - returns the journal's error state. | |
1542 | * @journal: journal to examine. | |
1543 | * | |
1544 | * This is the errno numbet set with journal_abort(), the last | |
1545 | * time the journal was mounted - if the journal was stopped | |
1546 | * without calling abort this will be 0. | |
1547 | * | |
1548 | * If the journal has been aborted on this mount time -EROFS will | |
1549 | * be returned. | |
1550 | */ | |
1551 | int journal_errno(journal_t *journal) | |
1552 | { | |
1553 | int err; | |
1554 | ||
1555 | spin_lock(&journal->j_state_lock); | |
1556 | if (journal->j_flags & JFS_ABORT) | |
1557 | err = -EROFS; | |
1558 | else | |
1559 | err = journal->j_errno; | |
1560 | spin_unlock(&journal->j_state_lock); | |
1561 | return err; | |
1562 | } | |
1563 | ||
1564 | /** | |
1565 | * int journal_clear_err () - clears the journal's error state | |
1566 | * @journal: journal to act on. | |
1567 | * | |
1568 | * An error must be cleared or Acked to take a FS out of readonly | |
1569 | * mode. | |
1570 | */ | |
1571 | int journal_clear_err(journal_t *journal) | |
1572 | { | |
1573 | int err = 0; | |
1574 | ||
1575 | spin_lock(&journal->j_state_lock); | |
1576 | if (journal->j_flags & JFS_ABORT) | |
1577 | err = -EROFS; | |
1578 | else | |
1579 | journal->j_errno = 0; | |
1580 | spin_unlock(&journal->j_state_lock); | |
1581 | return err; | |
1582 | } | |
1583 | ||
1584 | /** | |
1585 | * void journal_ack_err() - Ack journal err. | |
1586 | * @journal: journal to act on. | |
1587 | * | |
1588 | * An error must be cleared or Acked to take a FS out of readonly | |
1589 | * mode. | |
1590 | */ | |
1591 | void journal_ack_err(journal_t *journal) | |
1592 | { | |
1593 | spin_lock(&journal->j_state_lock); | |
1594 | if (journal->j_errno) | |
1595 | journal->j_flags |= JFS_ACK_ERR; | |
1596 | spin_unlock(&journal->j_state_lock); | |
1597 | } | |
1598 | ||
1599 | int journal_blocks_per_page(struct inode *inode) | |
1600 | { | |
1601 | return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); | |
1602 | } | |
1603 | ||
1604 | /* | |
1605 | * Simple support for retrying memory allocations. Introduced to help to | |
1606 | * debug different VM deadlock avoidance strategies. | |
1607 | */ | |
27496a8c | 1608 | void * __jbd_kmalloc (const char *where, size_t size, gfp_t flags, int retry) |
1da177e4 LT |
1609 | { |
1610 | return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0)); | |
1611 | } | |
1612 | ||
1613 | /* | |
1614 | * Journal_head storage management | |
1615 | */ | |
1616 | static kmem_cache_t *journal_head_cache; | |
1617 | #ifdef CONFIG_JBD_DEBUG | |
1618 | static atomic_t nr_journal_heads = ATOMIC_INIT(0); | |
1619 | #endif | |
1620 | ||
1621 | static int journal_init_journal_head_cache(void) | |
1622 | { | |
1623 | int retval; | |
1624 | ||
1625 | J_ASSERT(journal_head_cache == 0); | |
1626 | journal_head_cache = kmem_cache_create("journal_head", | |
1627 | sizeof(struct journal_head), | |
1628 | 0, /* offset */ | |
1629 | 0, /* flags */ | |
1630 | NULL, /* ctor */ | |
1631 | NULL); /* dtor */ | |
1632 | retval = 0; | |
1633 | if (journal_head_cache == 0) { | |
1634 | retval = -ENOMEM; | |
1635 | printk(KERN_EMERG "JBD: no memory for journal_head cache\n"); | |
1636 | } | |
1637 | return retval; | |
1638 | } | |
1639 | ||
1640 | static void journal_destroy_journal_head_cache(void) | |
1641 | { | |
1642 | J_ASSERT(journal_head_cache != NULL); | |
1643 | kmem_cache_destroy(journal_head_cache); | |
1644 | journal_head_cache = NULL; | |
1645 | } | |
1646 | ||
1647 | /* | |
1648 | * journal_head splicing and dicing | |
1649 | */ | |
1650 | static struct journal_head *journal_alloc_journal_head(void) | |
1651 | { | |
1652 | struct journal_head *ret; | |
1653 | static unsigned long last_warning; | |
1654 | ||
1655 | #ifdef CONFIG_JBD_DEBUG | |
1656 | atomic_inc(&nr_journal_heads); | |
1657 | #endif | |
1658 | ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS); | |
1659 | if (ret == 0) { | |
1660 | jbd_debug(1, "out of memory for journal_head\n"); | |
1661 | if (time_after(jiffies, last_warning + 5*HZ)) { | |
1662 | printk(KERN_NOTICE "ENOMEM in %s, retrying.\n", | |
1663 | __FUNCTION__); | |
1664 | last_warning = jiffies; | |
1665 | } | |
1666 | while (ret == 0) { | |
1667 | yield(); | |
1668 | ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS); | |
1669 | } | |
1670 | } | |
1671 | return ret; | |
1672 | } | |
1673 | ||
1674 | static void journal_free_journal_head(struct journal_head *jh) | |
1675 | { | |
1676 | #ifdef CONFIG_JBD_DEBUG | |
1677 | atomic_dec(&nr_journal_heads); | |
1678 | memset(jh, 0x5b, sizeof(*jh)); | |
1679 | #endif | |
1680 | kmem_cache_free(journal_head_cache, jh); | |
1681 | } | |
1682 | ||
1683 | /* | |
1684 | * A journal_head is attached to a buffer_head whenever JBD has an | |
1685 | * interest in the buffer. | |
1686 | * | |
1687 | * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit | |
1688 | * is set. This bit is tested in core kernel code where we need to take | |
1689 | * JBD-specific actions. Testing the zeroness of ->b_private is not reliable | |
1690 | * there. | |
1691 | * | |
1692 | * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one. | |
1693 | * | |
1694 | * When a buffer has its BH_JBD bit set it is immune from being released by | |
1695 | * core kernel code, mainly via ->b_count. | |
1696 | * | |
1697 | * A journal_head may be detached from its buffer_head when the journal_head's | |
1698 | * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL. | |
1699 | * Various places in JBD call journal_remove_journal_head() to indicate that the | |
1700 | * journal_head can be dropped if needed. | |
1701 | * | |
1702 | * Various places in the kernel want to attach a journal_head to a buffer_head | |
1703 | * _before_ attaching the journal_head to a transaction. To protect the | |
1704 | * journal_head in this situation, journal_add_journal_head elevates the | |
1705 | * journal_head's b_jcount refcount by one. The caller must call | |
1706 | * journal_put_journal_head() to undo this. | |
1707 | * | |
1708 | * So the typical usage would be: | |
1709 | * | |
1710 | * (Attach a journal_head if needed. Increments b_jcount) | |
1711 | * struct journal_head *jh = journal_add_journal_head(bh); | |
1712 | * ... | |
1713 | * jh->b_transaction = xxx; | |
1714 | * journal_put_journal_head(jh); | |
1715 | * | |
1716 | * Now, the journal_head's b_jcount is zero, but it is safe from being released | |
1717 | * because it has a non-zero b_transaction. | |
1718 | */ | |
1719 | ||
1720 | /* | |
1721 | * Give a buffer_head a journal_head. | |
1722 | * | |
1723 | * Doesn't need the journal lock. | |
1724 | * May sleep. | |
1725 | */ | |
1726 | struct journal_head *journal_add_journal_head(struct buffer_head *bh) | |
1727 | { | |
1728 | struct journal_head *jh; | |
1729 | struct journal_head *new_jh = NULL; | |
1730 | ||
1731 | repeat: | |
1732 | if (!buffer_jbd(bh)) { | |
1733 | new_jh = journal_alloc_journal_head(); | |
1734 | memset(new_jh, 0, sizeof(*new_jh)); | |
1735 | } | |
1736 | ||
1737 | jbd_lock_bh_journal_head(bh); | |
1738 | if (buffer_jbd(bh)) { | |
1739 | jh = bh2jh(bh); | |
1740 | } else { | |
1741 | J_ASSERT_BH(bh, | |
1742 | (atomic_read(&bh->b_count) > 0) || | |
1743 | (bh->b_page && bh->b_page->mapping)); | |
1744 | ||
1745 | if (!new_jh) { | |
1746 | jbd_unlock_bh_journal_head(bh); | |
1747 | goto repeat; | |
1748 | } | |
1749 | ||
1750 | jh = new_jh; | |
1751 | new_jh = NULL; /* We consumed it */ | |
1752 | set_buffer_jbd(bh); | |
1753 | bh->b_private = jh; | |
1754 | jh->b_bh = bh; | |
1755 | get_bh(bh); | |
1756 | BUFFER_TRACE(bh, "added journal_head"); | |
1757 | } | |
1758 | jh->b_jcount++; | |
1759 | jbd_unlock_bh_journal_head(bh); | |
1760 | if (new_jh) | |
1761 | journal_free_journal_head(new_jh); | |
1762 | return bh->b_private; | |
1763 | } | |
1764 | ||
1765 | /* | |
1766 | * Grab a ref against this buffer_head's journal_head. If it ended up not | |
1767 | * having a journal_head, return NULL | |
1768 | */ | |
1769 | struct journal_head *journal_grab_journal_head(struct buffer_head *bh) | |
1770 | { | |
1771 | struct journal_head *jh = NULL; | |
1772 | ||
1773 | jbd_lock_bh_journal_head(bh); | |
1774 | if (buffer_jbd(bh)) { | |
1775 | jh = bh2jh(bh); | |
1776 | jh->b_jcount++; | |
1777 | } | |
1778 | jbd_unlock_bh_journal_head(bh); | |
1779 | return jh; | |
1780 | } | |
1781 | ||
1782 | static void __journal_remove_journal_head(struct buffer_head *bh) | |
1783 | { | |
1784 | struct journal_head *jh = bh2jh(bh); | |
1785 | ||
1786 | J_ASSERT_JH(jh, jh->b_jcount >= 0); | |
1787 | ||
1788 | get_bh(bh); | |
1789 | if (jh->b_jcount == 0) { | |
1790 | if (jh->b_transaction == NULL && | |
1791 | jh->b_next_transaction == NULL && | |
1792 | jh->b_cp_transaction == NULL) { | |
1793 | J_ASSERT_JH(jh, jh->b_jlist == BJ_None); | |
1794 | J_ASSERT_BH(bh, buffer_jbd(bh)); | |
1795 | J_ASSERT_BH(bh, jh2bh(jh) == bh); | |
1796 | BUFFER_TRACE(bh, "remove journal_head"); | |
1797 | if (jh->b_frozen_data) { | |
1798 | printk(KERN_WARNING "%s: freeing " | |
1799 | "b_frozen_data\n", | |
1800 | __FUNCTION__); | |
1801 | kfree(jh->b_frozen_data); | |
1802 | } | |
1803 | if (jh->b_committed_data) { | |
1804 | printk(KERN_WARNING "%s: freeing " | |
1805 | "b_committed_data\n", | |
1806 | __FUNCTION__); | |
1807 | kfree(jh->b_committed_data); | |
1808 | } | |
1809 | bh->b_private = NULL; | |
1810 | jh->b_bh = NULL; /* debug, really */ | |
1811 | clear_buffer_jbd(bh); | |
1812 | __brelse(bh); | |
1813 | journal_free_journal_head(jh); | |
1814 | } else { | |
1815 | BUFFER_TRACE(bh, "journal_head was locked"); | |
1816 | } | |
1817 | } | |
1818 | } | |
1819 | ||
1820 | /* | |
1821 | * journal_remove_journal_head(): if the buffer isn't attached to a transaction | |
1822 | * and has a zero b_jcount then remove and release its journal_head. If we did | |
1823 | * see that the buffer is not used by any transaction we also "logically" | |
1824 | * decrement ->b_count. | |
1825 | * | |
1826 | * We in fact take an additional increment on ->b_count as a convenience, | |
1827 | * because the caller usually wants to do additional things with the bh | |
1828 | * after calling here. | |
1829 | * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some | |
1830 | * time. Once the caller has run __brelse(), the buffer is eligible for | |
1831 | * reaping by try_to_free_buffers(). | |
1832 | */ | |
1833 | void journal_remove_journal_head(struct buffer_head *bh) | |
1834 | { | |
1835 | jbd_lock_bh_journal_head(bh); | |
1836 | __journal_remove_journal_head(bh); | |
1837 | jbd_unlock_bh_journal_head(bh); | |
1838 | } | |
1839 | ||
1840 | /* | |
1841 | * Drop a reference on the passed journal_head. If it fell to zero then try to | |
1842 | * release the journal_head from the buffer_head. | |
1843 | */ | |
1844 | void journal_put_journal_head(struct journal_head *jh) | |
1845 | { | |
1846 | struct buffer_head *bh = jh2bh(jh); | |
1847 | ||
1848 | jbd_lock_bh_journal_head(bh); | |
1849 | J_ASSERT_JH(jh, jh->b_jcount > 0); | |
1850 | --jh->b_jcount; | |
1851 | if (!jh->b_jcount && !jh->b_transaction) { | |
1852 | __journal_remove_journal_head(bh); | |
1853 | __brelse(bh); | |
1854 | } | |
1855 | jbd_unlock_bh_journal_head(bh); | |
1856 | } | |
1857 | ||
1858 | /* | |
1859 | * /proc tunables | |
1860 | */ | |
1861 | #if defined(CONFIG_JBD_DEBUG) | |
1862 | int journal_enable_debug; | |
1863 | EXPORT_SYMBOL(journal_enable_debug); | |
1864 | #endif | |
1865 | ||
1866 | #if defined(CONFIG_JBD_DEBUG) && defined(CONFIG_PROC_FS) | |
1867 | ||
1868 | static struct proc_dir_entry *proc_jbd_debug; | |
1869 | ||
022a4a7b | 1870 | static int read_jbd_debug(char *page, char **start, off_t off, |
1da177e4 LT |
1871 | int count, int *eof, void *data) |
1872 | { | |
1873 | int ret; | |
1874 | ||
1875 | ret = sprintf(page + off, "%d\n", journal_enable_debug); | |
1876 | *eof = 1; | |
1877 | return ret; | |
1878 | } | |
1879 | ||
022a4a7b | 1880 | static int write_jbd_debug(struct file *file, const char __user *buffer, |
1da177e4 LT |
1881 | unsigned long count, void *data) |
1882 | { | |
1883 | char buf[32]; | |
1884 | ||
1885 | if (count > ARRAY_SIZE(buf) - 1) | |
1886 | count = ARRAY_SIZE(buf) - 1; | |
1887 | if (copy_from_user(buf, buffer, count)) | |
1888 | return -EFAULT; | |
1889 | buf[ARRAY_SIZE(buf) - 1] = '\0'; | |
1890 | journal_enable_debug = simple_strtoul(buf, NULL, 10); | |
1891 | return count; | |
1892 | } | |
1893 | ||
1894 | #define JBD_PROC_NAME "sys/fs/jbd-debug" | |
1895 | ||
1896 | static void __init create_jbd_proc_entry(void) | |
1897 | { | |
1898 | proc_jbd_debug = create_proc_entry(JBD_PROC_NAME, 0644, NULL); | |
1899 | if (proc_jbd_debug) { | |
1900 | /* Why is this so hard? */ | |
1901 | proc_jbd_debug->read_proc = read_jbd_debug; | |
1902 | proc_jbd_debug->write_proc = write_jbd_debug; | |
1903 | } | |
1904 | } | |
1905 | ||
1906 | static void __exit remove_jbd_proc_entry(void) | |
1907 | { | |
1908 | if (proc_jbd_debug) | |
1909 | remove_proc_entry(JBD_PROC_NAME, NULL); | |
1910 | } | |
1911 | ||
1912 | #else | |
1913 | ||
1914 | #define create_jbd_proc_entry() do {} while (0) | |
1915 | #define remove_jbd_proc_entry() do {} while (0) | |
1916 | ||
1917 | #endif | |
1918 | ||
1919 | kmem_cache_t *jbd_handle_cache; | |
1920 | ||
1921 | static int __init journal_init_handle_cache(void) | |
1922 | { | |
1923 | jbd_handle_cache = kmem_cache_create("journal_handle", | |
1924 | sizeof(handle_t), | |
1925 | 0, /* offset */ | |
1926 | 0, /* flags */ | |
1927 | NULL, /* ctor */ | |
1928 | NULL); /* dtor */ | |
1929 | if (jbd_handle_cache == NULL) { | |
1930 | printk(KERN_EMERG "JBD: failed to create handle cache\n"); | |
1931 | return -ENOMEM; | |
1932 | } | |
1933 | return 0; | |
1934 | } | |
1935 | ||
1936 | static void journal_destroy_handle_cache(void) | |
1937 | { | |
1938 | if (jbd_handle_cache) | |
1939 | kmem_cache_destroy(jbd_handle_cache); | |
1940 | } | |
1941 | ||
1942 | /* | |
1943 | * Module startup and shutdown | |
1944 | */ | |
1945 | ||
1946 | static int __init journal_init_caches(void) | |
1947 | { | |
1948 | int ret; | |
1949 | ||
1950 | ret = journal_init_revoke_caches(); | |
1951 | if (ret == 0) | |
1952 | ret = journal_init_journal_head_cache(); | |
1953 | if (ret == 0) | |
1954 | ret = journal_init_handle_cache(); | |
1955 | return ret; | |
1956 | } | |
1957 | ||
1958 | static void journal_destroy_caches(void) | |
1959 | { | |
1960 | journal_destroy_revoke_caches(); | |
1961 | journal_destroy_journal_head_cache(); | |
1962 | journal_destroy_handle_cache(); | |
1963 | } | |
1964 | ||
1965 | static int __init journal_init(void) | |
1966 | { | |
1967 | int ret; | |
1968 | ||
022a4a7b AB |
1969 | /* Static check for data structure consistency. There's no code |
1970 | * invoked --- we'll just get a linker failure if things aren't right. | |
1971 | */ | |
1972 | extern void journal_bad_superblock_size(void); | |
1973 | if (sizeof(struct journal_superblock_s) != 1024) | |
1974 | journal_bad_superblock_size(); | |
1975 | ||
1976 | ||
1da177e4 LT |
1977 | ret = journal_init_caches(); |
1978 | if (ret != 0) | |
1979 | journal_destroy_caches(); | |
1980 | create_jbd_proc_entry(); | |
1981 | return ret; | |
1982 | } | |
1983 | ||
1984 | static void __exit journal_exit(void) | |
1985 | { | |
1986 | #ifdef CONFIG_JBD_DEBUG | |
1987 | int n = atomic_read(&nr_journal_heads); | |
1988 | if (n) | |
1989 | printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n); | |
1990 | #endif | |
1991 | remove_jbd_proc_entry(); | |
1992 | journal_destroy_caches(); | |
1993 | } | |
1994 | ||
1995 | MODULE_LICENSE("GPL"); | |
1996 | module_init(journal_init); | |
1997 | module_exit(journal_exit); | |
1998 |