Commit | Line | Data |
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1da177e4 | 1 | /* |
58862699 | 2 | * linux/fs/jbd/revoke.c |
ae6ddcc5 | 3 | * |
1da177e4 LT |
4 | * Written by Stephen C. Tweedie <sct@redhat.com>, 2000 |
5 | * | |
6 | * Copyright 2000 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 | * Journal revoke routines for the generic filesystem journaling code; | |
13 | * part of the ext2fs journaling system. | |
14 | * | |
15 | * Revoke is the mechanism used to prevent old log records for deleted | |
16 | * metadata from being replayed on top of newer data using the same | |
17 | * blocks. The revoke mechanism is used in two separate places: | |
ae6ddcc5 | 18 | * |
1da177e4 LT |
19 | * + Commit: during commit we write the entire list of the current |
20 | * transaction's revoked blocks to the journal | |
ae6ddcc5 | 21 | * |
1da177e4 LT |
22 | * + Recovery: during recovery we record the transaction ID of all |
23 | * revoked blocks. If there are multiple revoke records in the log | |
24 | * for a single block, only the last one counts, and if there is a log | |
25 | * entry for a block beyond the last revoke, then that log entry still | |
26 | * gets replayed. | |
27 | * | |
28 | * We can get interactions between revokes and new log data within a | |
29 | * single transaction: | |
30 | * | |
31 | * Block is revoked and then journaled: | |
ae6ddcc5 | 32 | * The desired end result is the journaling of the new block, so we |
1da177e4 LT |
33 | * cancel the revoke before the transaction commits. |
34 | * | |
35 | * Block is journaled and then revoked: | |
36 | * The revoke must take precedence over the write of the block, so we | |
37 | * need either to cancel the journal entry or to write the revoke | |
38 | * later in the log than the log block. In this case, we choose the | |
39 | * latter: journaling a block cancels any revoke record for that block | |
40 | * in the current transaction, so any revoke for that block in the | |
41 | * transaction must have happened after the block was journaled and so | |
42 | * the revoke must take precedence. | |
43 | * | |
ae6ddcc5 | 44 | * Block is revoked and then written as data: |
1da177e4 LT |
45 | * The data write is allowed to succeed, but the revoke is _not_ |
46 | * cancelled. We still need to prevent old log records from | |
47 | * overwriting the new data. We don't even need to clear the revoke | |
48 | * bit here. | |
49 | * | |
50 | * Revoke information on buffers is a tri-state value: | |
51 | * | |
52 | * RevokeValid clear: no cached revoke status, need to look it up | |
53 | * RevokeValid set, Revoked clear: | |
54 | * buffer has not been revoked, and cancel_revoke | |
55 | * need do nothing. | |
56 | * RevokeValid set, Revoked set: | |
ae6ddcc5 | 57 | * buffer has been revoked. |
1da177e4 LT |
58 | */ |
59 | ||
60 | #ifndef __KERNEL__ | |
61 | #include "jfs_user.h" | |
62 | #else | |
63 | #include <linux/time.h> | |
64 | #include <linux/fs.h> | |
65 | #include <linux/jbd.h> | |
66 | #include <linux/errno.h> | |
67 | #include <linux/slab.h> | |
68 | #include <linux/list.h> | |
1da177e4 LT |
69 | #include <linux/init.h> |
70 | #endif | |
71 | ||
e18b890b CL |
72 | static struct kmem_cache *revoke_record_cache; |
73 | static struct kmem_cache *revoke_table_cache; | |
1da177e4 LT |
74 | |
75 | /* Each revoke record represents one single revoked block. During | |
76 | journal replay, this involves recording the transaction ID of the | |
77 | last transaction to revoke this block. */ | |
78 | ||
ae6ddcc5 | 79 | struct jbd_revoke_record_s |
1da177e4 LT |
80 | { |
81 | struct list_head hash; | |
82 | tid_t sequence; /* Used for recovery only */ | |
83 | unsigned long blocknr; | |
84 | }; | |
85 | ||
86 | ||
87 | /* The revoke table is just a simple hash table of revoke records. */ | |
88 | struct jbd_revoke_table_s | |
89 | { | |
90 | /* It is conceivable that we might want a larger hash table | |
91 | * for recovery. Must be a power of two. */ | |
ae6ddcc5 MC |
92 | int hash_size; |
93 | int hash_shift; | |
1da177e4 LT |
94 | struct list_head *hash_table; |
95 | }; | |
96 | ||
97 | ||
98 | #ifdef __KERNEL__ | |
99 | static void write_one_revoke_record(journal_t *, transaction_t *, | |
100 | struct journal_head **, int *, | |
101 | struct jbd_revoke_record_s *); | |
102 | static void flush_descriptor(journal_t *, struct journal_head *, int); | |
103 | #endif | |
104 | ||
105 | /* Utility functions to maintain the revoke table */ | |
106 | ||
107 | /* Borrowed from buffer.c: this is a tried and tested block hash function */ | |
108 | static inline int hash(journal_t *journal, unsigned long block) | |
109 | { | |
110 | struct jbd_revoke_table_s *table = journal->j_revoke; | |
111 | int hash_shift = table->hash_shift; | |
112 | ||
113 | return ((block << (hash_shift - 6)) ^ | |
114 | (block >> 13) ^ | |
115 | (block << (hash_shift - 12))) & (table->hash_size - 1); | |
116 | } | |
117 | ||
022a4a7b AB |
118 | static int insert_revoke_hash(journal_t *journal, unsigned long blocknr, |
119 | tid_t seq) | |
1da177e4 LT |
120 | { |
121 | struct list_head *hash_list; | |
122 | struct jbd_revoke_record_s *record; | |
123 | ||
124 | repeat: | |
125 | record = kmem_cache_alloc(revoke_record_cache, GFP_NOFS); | |
126 | if (!record) | |
127 | goto oom; | |
128 | ||
129 | record->sequence = seq; | |
130 | record->blocknr = blocknr; | |
131 | hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; | |
132 | spin_lock(&journal->j_revoke_lock); | |
133 | list_add(&record->hash, hash_list); | |
134 | spin_unlock(&journal->j_revoke_lock); | |
135 | return 0; | |
136 | ||
137 | oom: | |
138 | if (!journal_oom_retry) | |
139 | return -ENOMEM; | |
140 | jbd_debug(1, "ENOMEM in %s, retrying\n", __FUNCTION__); | |
141 | yield(); | |
142 | goto repeat; | |
143 | } | |
144 | ||
145 | /* Find a revoke record in the journal's hash table. */ | |
146 | ||
147 | static struct jbd_revoke_record_s *find_revoke_record(journal_t *journal, | |
148 | unsigned long blocknr) | |
149 | { | |
150 | struct list_head *hash_list; | |
151 | struct jbd_revoke_record_s *record; | |
152 | ||
153 | hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; | |
154 | ||
155 | spin_lock(&journal->j_revoke_lock); | |
156 | record = (struct jbd_revoke_record_s *) hash_list->next; | |
157 | while (&(record->hash) != hash_list) { | |
158 | if (record->blocknr == blocknr) { | |
159 | spin_unlock(&journal->j_revoke_lock); | |
160 | return record; | |
161 | } | |
162 | record = (struct jbd_revoke_record_s *) record->hash.next; | |
163 | } | |
164 | spin_unlock(&journal->j_revoke_lock); | |
165 | return NULL; | |
166 | } | |
167 | ||
168 | int __init journal_init_revoke_caches(void) | |
169 | { | |
170 | revoke_record_cache = kmem_cache_create("revoke_record", | |
171 | sizeof(struct jbd_revoke_record_s), | |
172 | 0, SLAB_HWCACHE_ALIGN, NULL, NULL); | |
173 | if (revoke_record_cache == 0) | |
174 | return -ENOMEM; | |
175 | ||
176 | revoke_table_cache = kmem_cache_create("revoke_table", | |
177 | sizeof(struct jbd_revoke_table_s), | |
178 | 0, 0, NULL, NULL); | |
179 | if (revoke_table_cache == 0) { | |
180 | kmem_cache_destroy(revoke_record_cache); | |
181 | revoke_record_cache = NULL; | |
182 | return -ENOMEM; | |
183 | } | |
184 | return 0; | |
185 | } | |
186 | ||
187 | void journal_destroy_revoke_caches(void) | |
188 | { | |
189 | kmem_cache_destroy(revoke_record_cache); | |
190 | revoke_record_cache = NULL; | |
191 | kmem_cache_destroy(revoke_table_cache); | |
192 | revoke_table_cache = NULL; | |
193 | } | |
194 | ||
195 | /* Initialise the revoke table for a given journal to a given size. */ | |
196 | ||
197 | int journal_init_revoke(journal_t *journal, int hash_size) | |
198 | { | |
199 | int shift, tmp; | |
200 | ||
201 | J_ASSERT (journal->j_revoke_table[0] == NULL); | |
202 | ||
203 | shift = 0; | |
204 | tmp = hash_size; | |
205 | while((tmp >>= 1UL) != 0UL) | |
206 | shift++; | |
207 | ||
208 | journal->j_revoke_table[0] = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL); | |
209 | if (!journal->j_revoke_table[0]) | |
210 | return -ENOMEM; | |
211 | journal->j_revoke = journal->j_revoke_table[0]; | |
212 | ||
213 | /* Check that the hash_size is a power of two */ | |
214 | J_ASSERT ((hash_size & (hash_size-1)) == 0); | |
215 | ||
216 | journal->j_revoke->hash_size = hash_size; | |
217 | ||
218 | journal->j_revoke->hash_shift = shift; | |
219 | ||
220 | journal->j_revoke->hash_table = | |
221 | kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); | |
222 | if (!journal->j_revoke->hash_table) { | |
223 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]); | |
224 | journal->j_revoke = NULL; | |
225 | return -ENOMEM; | |
226 | } | |
227 | ||
228 | for (tmp = 0; tmp < hash_size; tmp++) | |
229 | INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]); | |
230 | ||
231 | journal->j_revoke_table[1] = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL); | |
232 | if (!journal->j_revoke_table[1]) { | |
233 | kfree(journal->j_revoke_table[0]->hash_table); | |
234 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]); | |
235 | return -ENOMEM; | |
236 | } | |
237 | ||
238 | journal->j_revoke = journal->j_revoke_table[1]; | |
239 | ||
240 | /* Check that the hash_size is a power of two */ | |
241 | J_ASSERT ((hash_size & (hash_size-1)) == 0); | |
242 | ||
243 | journal->j_revoke->hash_size = hash_size; | |
244 | ||
245 | journal->j_revoke->hash_shift = shift; | |
246 | ||
247 | journal->j_revoke->hash_table = | |
248 | kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); | |
249 | if (!journal->j_revoke->hash_table) { | |
250 | kfree(journal->j_revoke_table[0]->hash_table); | |
251 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]); | |
252 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[1]); | |
253 | journal->j_revoke = NULL; | |
254 | return -ENOMEM; | |
255 | } | |
256 | ||
257 | for (tmp = 0; tmp < hash_size; tmp++) | |
258 | INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]); | |
259 | ||
260 | spin_lock_init(&journal->j_revoke_lock); | |
261 | ||
262 | return 0; | |
263 | } | |
264 | ||
265 | /* Destoy a journal's revoke table. The table must already be empty! */ | |
266 | ||
267 | void journal_destroy_revoke(journal_t *journal) | |
268 | { | |
269 | struct jbd_revoke_table_s *table; | |
270 | struct list_head *hash_list; | |
271 | int i; | |
272 | ||
273 | table = journal->j_revoke_table[0]; | |
274 | if (!table) | |
275 | return; | |
276 | ||
277 | for (i=0; i<table->hash_size; i++) { | |
278 | hash_list = &table->hash_table[i]; | |
279 | J_ASSERT (list_empty(hash_list)); | |
280 | } | |
281 | ||
282 | kfree(table->hash_table); | |
283 | kmem_cache_free(revoke_table_cache, table); | |
284 | journal->j_revoke = NULL; | |
285 | ||
286 | table = journal->j_revoke_table[1]; | |
287 | if (!table) | |
288 | return; | |
289 | ||
290 | for (i=0; i<table->hash_size; i++) { | |
291 | hash_list = &table->hash_table[i]; | |
292 | J_ASSERT (list_empty(hash_list)); | |
293 | } | |
294 | ||
295 | kfree(table->hash_table); | |
296 | kmem_cache_free(revoke_table_cache, table); | |
297 | journal->j_revoke = NULL; | |
298 | } | |
299 | ||
300 | ||
301 | #ifdef __KERNEL__ | |
302 | ||
ae6ddcc5 | 303 | /* |
1da177e4 LT |
304 | * journal_revoke: revoke a given buffer_head from the journal. This |
305 | * prevents the block from being replayed during recovery if we take a | |
306 | * crash after this current transaction commits. Any subsequent | |
307 | * metadata writes of the buffer in this transaction cancel the | |
ae6ddcc5 | 308 | * revoke. |
1da177e4 LT |
309 | * |
310 | * Note that this call may block --- it is up to the caller to make | |
311 | * sure that there are no further calls to journal_write_metadata | |
312 | * before the revoke is complete. In ext3, this implies calling the | |
313 | * revoke before clearing the block bitmap when we are deleting | |
ae6ddcc5 | 314 | * metadata. |
1da177e4 LT |
315 | * |
316 | * Revoke performs a journal_forget on any buffer_head passed in as a | |
317 | * parameter, but does _not_ forget the buffer_head if the bh was only | |
ae6ddcc5 | 318 | * found implicitly. |
1da177e4 LT |
319 | * |
320 | * bh_in may not be a journalled buffer - it may have come off | |
321 | * the hash tables without an attached journal_head. | |
322 | * | |
323 | * If bh_in is non-zero, journal_revoke() will decrement its b_count | |
324 | * by one. | |
325 | */ | |
326 | ||
ae6ddcc5 | 327 | int journal_revoke(handle_t *handle, unsigned long blocknr, |
1da177e4 LT |
328 | struct buffer_head *bh_in) |
329 | { | |
330 | struct buffer_head *bh = NULL; | |
331 | journal_t *journal; | |
332 | struct block_device *bdev; | |
333 | int err; | |
334 | ||
335 | might_sleep(); | |
336 | if (bh_in) | |
337 | BUFFER_TRACE(bh_in, "enter"); | |
338 | ||
339 | journal = handle->h_transaction->t_journal; | |
340 | if (!journal_set_features(journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)){ | |
341 | J_ASSERT (!"Cannot set revoke feature!"); | |
342 | return -EINVAL; | |
343 | } | |
344 | ||
345 | bdev = journal->j_fs_dev; | |
346 | bh = bh_in; | |
347 | ||
348 | if (!bh) { | |
349 | bh = __find_get_block(bdev, blocknr, journal->j_blocksize); | |
350 | if (bh) | |
351 | BUFFER_TRACE(bh, "found on hash"); | |
352 | } | |
353 | #ifdef JBD_EXPENSIVE_CHECKING | |
354 | else { | |
355 | struct buffer_head *bh2; | |
356 | ||
357 | /* If there is a different buffer_head lying around in | |
358 | * memory anywhere... */ | |
359 | bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize); | |
360 | if (bh2) { | |
361 | /* ... and it has RevokeValid status... */ | |
362 | if (bh2 != bh && buffer_revokevalid(bh2)) | |
363 | /* ...then it better be revoked too, | |
364 | * since it's illegal to create a revoke | |
365 | * record against a buffer_head which is | |
366 | * not marked revoked --- that would | |
367 | * risk missing a subsequent revoke | |
368 | * cancel. */ | |
369 | J_ASSERT_BH(bh2, buffer_revoked(bh2)); | |
370 | put_bh(bh2); | |
371 | } | |
372 | } | |
373 | #endif | |
374 | ||
375 | /* We really ought not ever to revoke twice in a row without | |
376 | first having the revoke cancelled: it's illegal to free a | |
377 | block twice without allocating it in between! */ | |
378 | if (bh) { | |
379 | if (!J_EXPECT_BH(bh, !buffer_revoked(bh), | |
380 | "inconsistent data on disk")) { | |
381 | if (!bh_in) | |
382 | brelse(bh); | |
383 | return -EIO; | |
384 | } | |
385 | set_buffer_revoked(bh); | |
386 | set_buffer_revokevalid(bh); | |
387 | if (bh_in) { | |
388 | BUFFER_TRACE(bh_in, "call journal_forget"); | |
389 | journal_forget(handle, bh_in); | |
390 | } else { | |
391 | BUFFER_TRACE(bh, "call brelse"); | |
392 | __brelse(bh); | |
393 | } | |
394 | } | |
395 | ||
396 | jbd_debug(2, "insert revoke for block %lu, bh_in=%p\n", blocknr, bh_in); | |
397 | err = insert_revoke_hash(journal, blocknr, | |
398 | handle->h_transaction->t_tid); | |
399 | BUFFER_TRACE(bh_in, "exit"); | |
400 | return err; | |
401 | } | |
402 | ||
403 | /* | |
404 | * Cancel an outstanding revoke. For use only internally by the | |
405 | * journaling code (called from journal_get_write_access). | |
406 | * | |
407 | * We trust buffer_revoked() on the buffer if the buffer is already | |
408 | * being journaled: if there is no revoke pending on the buffer, then we | |
409 | * don't do anything here. | |
410 | * | |
411 | * This would break if it were possible for a buffer to be revoked and | |
412 | * discarded, and then reallocated within the same transaction. In such | |
413 | * a case we would have lost the revoked bit, but when we arrived here | |
414 | * the second time we would still have a pending revoke to cancel. So, | |
415 | * do not trust the Revoked bit on buffers unless RevokeValid is also | |
416 | * set. | |
417 | * | |
418 | * The caller must have the journal locked. | |
419 | */ | |
420 | int journal_cancel_revoke(handle_t *handle, struct journal_head *jh) | |
421 | { | |
422 | struct jbd_revoke_record_s *record; | |
423 | journal_t *journal = handle->h_transaction->t_journal; | |
424 | int need_cancel; | |
425 | int did_revoke = 0; /* akpm: debug */ | |
426 | struct buffer_head *bh = jh2bh(jh); | |
427 | ||
428 | jbd_debug(4, "journal_head %p, cancelling revoke\n", jh); | |
429 | ||
430 | /* Is the existing Revoke bit valid? If so, we trust it, and | |
431 | * only perform the full cancel if the revoke bit is set. If | |
432 | * not, we can't trust the revoke bit, and we need to do the | |
433 | * full search for a revoke record. */ | |
434 | if (test_set_buffer_revokevalid(bh)) { | |
435 | need_cancel = test_clear_buffer_revoked(bh); | |
436 | } else { | |
437 | need_cancel = 1; | |
438 | clear_buffer_revoked(bh); | |
439 | } | |
440 | ||
441 | if (need_cancel) { | |
442 | record = find_revoke_record(journal, bh->b_blocknr); | |
443 | if (record) { | |
444 | jbd_debug(4, "cancelled existing revoke on " | |
445 | "blocknr %llu\n", (unsigned long long)bh->b_blocknr); | |
446 | spin_lock(&journal->j_revoke_lock); | |
447 | list_del(&record->hash); | |
448 | spin_unlock(&journal->j_revoke_lock); | |
449 | kmem_cache_free(revoke_record_cache, record); | |
450 | did_revoke = 1; | |
451 | } | |
452 | } | |
453 | ||
454 | #ifdef JBD_EXPENSIVE_CHECKING | |
455 | /* There better not be one left behind by now! */ | |
456 | record = find_revoke_record(journal, bh->b_blocknr); | |
457 | J_ASSERT_JH(jh, record == NULL); | |
458 | #endif | |
459 | ||
460 | /* Finally, have we just cleared revoke on an unhashed | |
461 | * buffer_head? If so, we'd better make sure we clear the | |
462 | * revoked status on any hashed alias too, otherwise the revoke | |
463 | * state machine will get very upset later on. */ | |
464 | if (need_cancel) { | |
465 | struct buffer_head *bh2; | |
466 | bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size); | |
467 | if (bh2) { | |
468 | if (bh2 != bh) | |
469 | clear_buffer_revoked(bh2); | |
470 | __brelse(bh2); | |
471 | } | |
472 | } | |
473 | return did_revoke; | |
474 | } | |
475 | ||
476 | /* journal_switch_revoke table select j_revoke for next transaction | |
477 | * we do not want to suspend any processing until all revokes are | |
478 | * written -bzzz | |
479 | */ | |
480 | void journal_switch_revoke_table(journal_t *journal) | |
481 | { | |
482 | int i; | |
483 | ||
484 | if (journal->j_revoke == journal->j_revoke_table[0]) | |
485 | journal->j_revoke = journal->j_revoke_table[1]; | |
486 | else | |
487 | journal->j_revoke = journal->j_revoke_table[0]; | |
488 | ||
ae6ddcc5 | 489 | for (i = 0; i < journal->j_revoke->hash_size; i++) |
1da177e4 LT |
490 | INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]); |
491 | } | |
492 | ||
493 | /* | |
494 | * Write revoke records to the journal for all entries in the current | |
495 | * revoke hash, deleting the entries as we go. | |
496 | * | |
497 | * Called with the journal lock held. | |
498 | */ | |
499 | ||
ae6ddcc5 | 500 | void journal_write_revoke_records(journal_t *journal, |
1da177e4 LT |
501 | transaction_t *transaction) |
502 | { | |
503 | struct journal_head *descriptor; | |
504 | struct jbd_revoke_record_s *record; | |
505 | struct jbd_revoke_table_s *revoke; | |
506 | struct list_head *hash_list; | |
507 | int i, offset, count; | |
508 | ||
ae6ddcc5 | 509 | descriptor = NULL; |
1da177e4 LT |
510 | offset = 0; |
511 | count = 0; | |
512 | ||
513 | /* select revoke table for committing transaction */ | |
514 | revoke = journal->j_revoke == journal->j_revoke_table[0] ? | |
515 | journal->j_revoke_table[1] : journal->j_revoke_table[0]; | |
516 | ||
517 | for (i = 0; i < revoke->hash_size; i++) { | |
518 | hash_list = &revoke->hash_table[i]; | |
519 | ||
520 | while (!list_empty(hash_list)) { | |
ae6ddcc5 | 521 | record = (struct jbd_revoke_record_s *) |
1da177e4 LT |
522 | hash_list->next; |
523 | write_one_revoke_record(journal, transaction, | |
ae6ddcc5 | 524 | &descriptor, &offset, |
1da177e4 LT |
525 | record); |
526 | count++; | |
527 | list_del(&record->hash); | |
528 | kmem_cache_free(revoke_record_cache, record); | |
529 | } | |
530 | } | |
531 | if (descriptor) | |
532 | flush_descriptor(journal, descriptor, offset); | |
533 | jbd_debug(1, "Wrote %d revoke records\n", count); | |
534 | } | |
535 | ||
ae6ddcc5 | 536 | /* |
1da177e4 | 537 | * Write out one revoke record. We need to create a new descriptor |
ae6ddcc5 | 538 | * block if the old one is full or if we have not already created one. |
1da177e4 LT |
539 | */ |
540 | ||
ae6ddcc5 | 541 | static void write_one_revoke_record(journal_t *journal, |
1da177e4 | 542 | transaction_t *transaction, |
ae6ddcc5 | 543 | struct journal_head **descriptorp, |
1da177e4 LT |
544 | int *offsetp, |
545 | struct jbd_revoke_record_s *record) | |
546 | { | |
547 | struct journal_head *descriptor; | |
548 | int offset; | |
549 | journal_header_t *header; | |
550 | ||
551 | /* If we are already aborting, this all becomes a noop. We | |
552 | still need to go round the loop in | |
553 | journal_write_revoke_records in order to free all of the | |
554 | revoke records: only the IO to the journal is omitted. */ | |
555 | if (is_journal_aborted(journal)) | |
556 | return; | |
557 | ||
558 | descriptor = *descriptorp; | |
559 | offset = *offsetp; | |
560 | ||
561 | /* Make sure we have a descriptor with space left for the record */ | |
562 | if (descriptor) { | |
563 | if (offset == journal->j_blocksize) { | |
564 | flush_descriptor(journal, descriptor, offset); | |
565 | descriptor = NULL; | |
566 | } | |
567 | } | |
568 | ||
569 | if (!descriptor) { | |
570 | descriptor = journal_get_descriptor_buffer(journal); | |
571 | if (!descriptor) | |
572 | return; | |
573 | header = (journal_header_t *) &jh2bh(descriptor)->b_data[0]; | |
574 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
575 | header->h_blocktype = cpu_to_be32(JFS_REVOKE_BLOCK); | |
576 | header->h_sequence = cpu_to_be32(transaction->t_tid); | |
577 | ||
578 | /* Record it so that we can wait for IO completion later */ | |
579 | JBUFFER_TRACE(descriptor, "file as BJ_LogCtl"); | |
580 | journal_file_buffer(descriptor, transaction, BJ_LogCtl); | |
581 | ||
582 | offset = sizeof(journal_revoke_header_t); | |
583 | *descriptorp = descriptor; | |
584 | } | |
585 | ||
ae6ddcc5 | 586 | * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) = |
1da177e4 LT |
587 | cpu_to_be32(record->blocknr); |
588 | offset += 4; | |
589 | *offsetp = offset; | |
590 | } | |
591 | ||
ae6ddcc5 | 592 | /* |
1da177e4 LT |
593 | * Flush a revoke descriptor out to the journal. If we are aborting, |
594 | * this is a noop; otherwise we are generating a buffer which needs to | |
595 | * be waited for during commit, so it has to go onto the appropriate | |
596 | * journal buffer list. | |
597 | */ | |
598 | ||
ae6ddcc5 MC |
599 | static void flush_descriptor(journal_t *journal, |
600 | struct journal_head *descriptor, | |
1da177e4 LT |
601 | int offset) |
602 | { | |
603 | journal_revoke_header_t *header; | |
604 | struct buffer_head *bh = jh2bh(descriptor); | |
605 | ||
606 | if (is_journal_aborted(journal)) { | |
607 | put_bh(bh); | |
608 | return; | |
609 | } | |
610 | ||
611 | header = (journal_revoke_header_t *) jh2bh(descriptor)->b_data; | |
612 | header->r_count = cpu_to_be32(offset); | |
613 | set_buffer_jwrite(bh); | |
614 | BUFFER_TRACE(bh, "write"); | |
615 | set_buffer_dirty(bh); | |
26707699 | 616 | ll_rw_block(SWRITE, 1, &bh); |
1da177e4 LT |
617 | } |
618 | #endif | |
619 | ||
ae6ddcc5 | 620 | /* |
1da177e4 LT |
621 | * Revoke support for recovery. |
622 | * | |
623 | * Recovery needs to be able to: | |
624 | * | |
625 | * record all revoke records, including the tid of the latest instance | |
626 | * of each revoke in the journal | |
627 | * | |
628 | * check whether a given block in a given transaction should be replayed | |
629 | * (ie. has not been revoked by a revoke record in that or a subsequent | |
630 | * transaction) | |
ae6ddcc5 | 631 | * |
1da177e4 LT |
632 | * empty the revoke table after recovery. |
633 | */ | |
634 | ||
635 | /* | |
636 | * First, setting revoke records. We create a new revoke record for | |
637 | * every block ever revoked in the log as we scan it for recovery, and | |
638 | * we update the existing records if we find multiple revokes for a | |
ae6ddcc5 | 639 | * single block. |
1da177e4 LT |
640 | */ |
641 | ||
ae6ddcc5 MC |
642 | int journal_set_revoke(journal_t *journal, |
643 | unsigned long blocknr, | |
1da177e4 LT |
644 | tid_t sequence) |
645 | { | |
646 | struct jbd_revoke_record_s *record; | |
647 | ||
648 | record = find_revoke_record(journal, blocknr); | |
649 | if (record) { | |
650 | /* If we have multiple occurrences, only record the | |
651 | * latest sequence number in the hashed record */ | |
652 | if (tid_gt(sequence, record->sequence)) | |
653 | record->sequence = sequence; | |
654 | return 0; | |
ae6ddcc5 | 655 | } |
1da177e4 LT |
656 | return insert_revoke_hash(journal, blocknr, sequence); |
657 | } | |
658 | ||
ae6ddcc5 | 659 | /* |
1da177e4 LT |
660 | * Test revoke records. For a given block referenced in the log, has |
661 | * that block been revoked? A revoke record with a given transaction | |
662 | * sequence number revokes all blocks in that transaction and earlier | |
663 | * ones, but later transactions still need replayed. | |
664 | */ | |
665 | ||
ae6ddcc5 | 666 | int journal_test_revoke(journal_t *journal, |
1da177e4 LT |
667 | unsigned long blocknr, |
668 | tid_t sequence) | |
669 | { | |
670 | struct jbd_revoke_record_s *record; | |
671 | ||
672 | record = find_revoke_record(journal, blocknr); | |
673 | if (!record) | |
674 | return 0; | |
675 | if (tid_gt(sequence, record->sequence)) | |
676 | return 0; | |
677 | return 1; | |
678 | } | |
679 | ||
680 | /* | |
681 | * Finally, once recovery is over, we need to clear the revoke table so | |
682 | * that it can be reused by the running filesystem. | |
683 | */ | |
684 | ||
685 | void journal_clear_revoke(journal_t *journal) | |
686 | { | |
687 | int i; | |
688 | struct list_head *hash_list; | |
689 | struct jbd_revoke_record_s *record; | |
690 | struct jbd_revoke_table_s *revoke; | |
691 | ||
692 | revoke = journal->j_revoke; | |
693 | ||
694 | for (i = 0; i < revoke->hash_size; i++) { | |
695 | hash_list = &revoke->hash_table[i]; | |
696 | while (!list_empty(hash_list)) { | |
697 | record = (struct jbd_revoke_record_s*) hash_list->next; | |
698 | list_del(&record->hash); | |
699 | kmem_cache_free(revoke_record_cache, record); | |
700 | } | |
701 | } | |
702 | } |