diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/jbd/revoke.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/jbd/revoke.c')
-rw-r--r-- | fs/jbd/revoke.c | 702 |
1 files changed, 702 insertions, 0 deletions
diff --git a/fs/jbd/revoke.c b/fs/jbd/revoke.c new file mode 100644 index 000000000000..d327a598f861 --- /dev/null +++ b/fs/jbd/revoke.c | |||
@@ -0,0 +1,702 @@ | |||
1 | /* | ||
2 | * linux/fs/revoke.c | ||
3 | * | ||
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: | ||
18 | * | ||
19 | * + Commit: during commit we write the entire list of the current | ||
20 | * transaction's revoked blocks to the journal | ||
21 | * | ||
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: | ||
32 | * The desired end result is the journaling of the new block, so we | ||
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 | * | ||
44 | * Block is revoked and then written as data: | ||
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: | ||
57 | * buffer has been revoked. | ||
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> | ||
69 | #include <linux/smp_lock.h> | ||
70 | #include <linux/init.h> | ||
71 | #endif | ||
72 | |||
73 | static kmem_cache_t *revoke_record_cache; | ||
74 | static kmem_cache_t *revoke_table_cache; | ||
75 | |||
76 | /* Each revoke record represents one single revoked block. During | ||
77 | journal replay, this involves recording the transaction ID of the | ||
78 | last transaction to revoke this block. */ | ||
79 | |||
80 | struct jbd_revoke_record_s | ||
81 | { | ||
82 | struct list_head hash; | ||
83 | tid_t sequence; /* Used for recovery only */ | ||
84 | unsigned long blocknr; | ||
85 | }; | ||
86 | |||
87 | |||
88 | /* The revoke table is just a simple hash table of revoke records. */ | ||
89 | struct jbd_revoke_table_s | ||
90 | { | ||
91 | /* It is conceivable that we might want a larger hash table | ||
92 | * for recovery. Must be a power of two. */ | ||
93 | int hash_size; | ||
94 | int hash_shift; | ||
95 | struct list_head *hash_table; | ||
96 | }; | ||
97 | |||
98 | |||
99 | #ifdef __KERNEL__ | ||
100 | static void write_one_revoke_record(journal_t *, transaction_t *, | ||
101 | struct journal_head **, int *, | ||
102 | struct jbd_revoke_record_s *); | ||
103 | static void flush_descriptor(journal_t *, struct journal_head *, int); | ||
104 | #endif | ||
105 | |||
106 | /* Utility functions to maintain the revoke table */ | ||
107 | |||
108 | /* Borrowed from buffer.c: this is a tried and tested block hash function */ | ||
109 | static inline int hash(journal_t *journal, unsigned long block) | ||
110 | { | ||
111 | struct jbd_revoke_table_s *table = journal->j_revoke; | ||
112 | int hash_shift = table->hash_shift; | ||
113 | |||
114 | return ((block << (hash_shift - 6)) ^ | ||
115 | (block >> 13) ^ | ||
116 | (block << (hash_shift - 12))) & (table->hash_size - 1); | ||
117 | } | ||
118 | |||
119 | int insert_revoke_hash(journal_t *journal, unsigned long blocknr, tid_t seq) | ||
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 | |||
303 | /* | ||
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 | ||
308 | * revoke. | ||
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 | ||
314 | * metadata. | ||
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 | ||
318 | * found implicitly. | ||
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 | |||
327 | int journal_revoke(handle_t *handle, unsigned long blocknr, | ||
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 | |||
489 | for (i = 0; i < journal->j_revoke->hash_size; i++) | ||
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 | |||
500 | void journal_write_revoke_records(journal_t *journal, | ||
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 | |||
509 | descriptor = NULL; | ||
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)) { | ||
521 | record = (struct jbd_revoke_record_s *) | ||
522 | hash_list->next; | ||
523 | write_one_revoke_record(journal, transaction, | ||
524 | &descriptor, &offset, | ||
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 | |||
536 | /* | ||
537 | * Write out one revoke record. We need to create a new descriptor | ||
538 | * block if the old one is full or if we have not already created one. | ||
539 | */ | ||
540 | |||
541 | static void write_one_revoke_record(journal_t *journal, | ||
542 | transaction_t *transaction, | ||
543 | struct journal_head **descriptorp, | ||
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 | |||
586 | * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) = | ||
587 | cpu_to_be32(record->blocknr); | ||
588 | offset += 4; | ||
589 | *offsetp = offset; | ||
590 | } | ||
591 | |||
592 | /* | ||
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 | |||
599 | static void flush_descriptor(journal_t *journal, | ||
600 | struct journal_head *descriptor, | ||
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); | ||
616 | ll_rw_block(WRITE, 1, &bh); | ||
617 | } | ||
618 | #endif | ||
619 | |||
620 | /* | ||
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) | ||
631 | * | ||
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 | ||
639 | * single block. | ||
640 | */ | ||
641 | |||
642 | int journal_set_revoke(journal_t *journal, | ||
643 | unsigned long blocknr, | ||
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; | ||
655 | } | ||
656 | return insert_revoke_hash(journal, blocknr, sequence); | ||
657 | } | ||
658 | |||
659 | /* | ||
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 | |||
666 | int journal_test_revoke(journal_t *journal, | ||
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 | } | ||