diff options
author | Dave Kleikamp <shaggy@austin.ibm.com> | 2006-10-11 04:20:57 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-11 14:14:15 -0400 |
commit | 470decc613ab2048b619a01028072d932d9086ee (patch) | |
tree | 5268576f5099040db94b8e984983c0bb28b2a9a7 /fs/jbd2/revoke.c | |
parent | 02ea2104c55b625cf5b5d9ba8586a4fc17920f5c (diff) |
[PATCH] jbd2: initial copy of files from jbd
This is a simple copy of the files in fs/jbd to fs/jbd2 and
/usr/incude/linux/[ext4_]jbd.h to /usr/include/[ext4_]jbd2.h
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/jbd2/revoke.c')
-rw-r--r-- | fs/jbd2/revoke.c | 703 |
1 files changed, 703 insertions, 0 deletions
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c new file mode 100644 index 000000000000..c532429d8d9b --- /dev/null +++ b/fs/jbd2/revoke.c | |||
@@ -0,0 +1,703 @@ | |||
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 | static int insert_revoke_hash(journal_t *journal, unsigned long blocknr, | ||
120 | tid_t seq) | ||
121 | { | ||
122 | struct list_head *hash_list; | ||
123 | struct jbd_revoke_record_s *record; | ||
124 | |||
125 | repeat: | ||
126 | record = kmem_cache_alloc(revoke_record_cache, GFP_NOFS); | ||
127 | if (!record) | ||
128 | goto oom; | ||
129 | |||
130 | record->sequence = seq; | ||
131 | record->blocknr = blocknr; | ||
132 | hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; | ||
133 | spin_lock(&journal->j_revoke_lock); | ||
134 | list_add(&record->hash, hash_list); | ||
135 | spin_unlock(&journal->j_revoke_lock); | ||
136 | return 0; | ||
137 | |||
138 | oom: | ||
139 | if (!journal_oom_retry) | ||
140 | return -ENOMEM; | ||
141 | jbd_debug(1, "ENOMEM in %s, retrying\n", __FUNCTION__); | ||
142 | yield(); | ||
143 | goto repeat; | ||
144 | } | ||
145 | |||
146 | /* Find a revoke record in the journal's hash table. */ | ||
147 | |||
148 | static struct jbd_revoke_record_s *find_revoke_record(journal_t *journal, | ||
149 | unsigned long blocknr) | ||
150 | { | ||
151 | struct list_head *hash_list; | ||
152 | struct jbd_revoke_record_s *record; | ||
153 | |||
154 | hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; | ||
155 | |||
156 | spin_lock(&journal->j_revoke_lock); | ||
157 | record = (struct jbd_revoke_record_s *) hash_list->next; | ||
158 | while (&(record->hash) != hash_list) { | ||
159 | if (record->blocknr == blocknr) { | ||
160 | spin_unlock(&journal->j_revoke_lock); | ||
161 | return record; | ||
162 | } | ||
163 | record = (struct jbd_revoke_record_s *) record->hash.next; | ||
164 | } | ||
165 | spin_unlock(&journal->j_revoke_lock); | ||
166 | return NULL; | ||
167 | } | ||
168 | |||
169 | int __init journal_init_revoke_caches(void) | ||
170 | { | ||
171 | revoke_record_cache = kmem_cache_create("revoke_record", | ||
172 | sizeof(struct jbd_revoke_record_s), | ||
173 | 0, SLAB_HWCACHE_ALIGN, NULL, NULL); | ||
174 | if (revoke_record_cache == 0) | ||
175 | return -ENOMEM; | ||
176 | |||
177 | revoke_table_cache = kmem_cache_create("revoke_table", | ||
178 | sizeof(struct jbd_revoke_table_s), | ||
179 | 0, 0, NULL, NULL); | ||
180 | if (revoke_table_cache == 0) { | ||
181 | kmem_cache_destroy(revoke_record_cache); | ||
182 | revoke_record_cache = NULL; | ||
183 | return -ENOMEM; | ||
184 | } | ||
185 | return 0; | ||
186 | } | ||
187 | |||
188 | void journal_destroy_revoke_caches(void) | ||
189 | { | ||
190 | kmem_cache_destroy(revoke_record_cache); | ||
191 | revoke_record_cache = NULL; | ||
192 | kmem_cache_destroy(revoke_table_cache); | ||
193 | revoke_table_cache = NULL; | ||
194 | } | ||
195 | |||
196 | /* Initialise the revoke table for a given journal to a given size. */ | ||
197 | |||
198 | int journal_init_revoke(journal_t *journal, int hash_size) | ||
199 | { | ||
200 | int shift, tmp; | ||
201 | |||
202 | J_ASSERT (journal->j_revoke_table[0] == NULL); | ||
203 | |||
204 | shift = 0; | ||
205 | tmp = hash_size; | ||
206 | while((tmp >>= 1UL) != 0UL) | ||
207 | shift++; | ||
208 | |||
209 | journal->j_revoke_table[0] = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL); | ||
210 | if (!journal->j_revoke_table[0]) | ||
211 | return -ENOMEM; | ||
212 | journal->j_revoke = journal->j_revoke_table[0]; | ||
213 | |||
214 | /* Check that the hash_size is a power of two */ | ||
215 | J_ASSERT ((hash_size & (hash_size-1)) == 0); | ||
216 | |||
217 | journal->j_revoke->hash_size = hash_size; | ||
218 | |||
219 | journal->j_revoke->hash_shift = shift; | ||
220 | |||
221 | journal->j_revoke->hash_table = | ||
222 | kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); | ||
223 | if (!journal->j_revoke->hash_table) { | ||
224 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]); | ||
225 | journal->j_revoke = NULL; | ||
226 | return -ENOMEM; | ||
227 | } | ||
228 | |||
229 | for (tmp = 0; tmp < hash_size; tmp++) | ||
230 | INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]); | ||
231 | |||
232 | journal->j_revoke_table[1] = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL); | ||
233 | if (!journal->j_revoke_table[1]) { | ||
234 | kfree(journal->j_revoke_table[0]->hash_table); | ||
235 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]); | ||
236 | return -ENOMEM; | ||
237 | } | ||
238 | |||
239 | journal->j_revoke = journal->j_revoke_table[1]; | ||
240 | |||
241 | /* Check that the hash_size is a power of two */ | ||
242 | J_ASSERT ((hash_size & (hash_size-1)) == 0); | ||
243 | |||
244 | journal->j_revoke->hash_size = hash_size; | ||
245 | |||
246 | journal->j_revoke->hash_shift = shift; | ||
247 | |||
248 | journal->j_revoke->hash_table = | ||
249 | kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); | ||
250 | if (!journal->j_revoke->hash_table) { | ||
251 | kfree(journal->j_revoke_table[0]->hash_table); | ||
252 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[0]); | ||
253 | kmem_cache_free(revoke_table_cache, journal->j_revoke_table[1]); | ||
254 | journal->j_revoke = NULL; | ||
255 | return -ENOMEM; | ||
256 | } | ||
257 | |||
258 | for (tmp = 0; tmp < hash_size; tmp++) | ||
259 | INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]); | ||
260 | |||
261 | spin_lock_init(&journal->j_revoke_lock); | ||
262 | |||
263 | return 0; | ||
264 | } | ||
265 | |||
266 | /* Destoy a journal's revoke table. The table must already be empty! */ | ||
267 | |||
268 | void journal_destroy_revoke(journal_t *journal) | ||
269 | { | ||
270 | struct jbd_revoke_table_s *table; | ||
271 | struct list_head *hash_list; | ||
272 | int i; | ||
273 | |||
274 | table = journal->j_revoke_table[0]; | ||
275 | if (!table) | ||
276 | return; | ||
277 | |||
278 | for (i=0; i<table->hash_size; i++) { | ||
279 | hash_list = &table->hash_table[i]; | ||
280 | J_ASSERT (list_empty(hash_list)); | ||
281 | } | ||
282 | |||
283 | kfree(table->hash_table); | ||
284 | kmem_cache_free(revoke_table_cache, table); | ||
285 | journal->j_revoke = NULL; | ||
286 | |||
287 | table = journal->j_revoke_table[1]; | ||
288 | if (!table) | ||
289 | return; | ||
290 | |||
291 | for (i=0; i<table->hash_size; i++) { | ||
292 | hash_list = &table->hash_table[i]; | ||
293 | J_ASSERT (list_empty(hash_list)); | ||
294 | } | ||
295 | |||
296 | kfree(table->hash_table); | ||
297 | kmem_cache_free(revoke_table_cache, table); | ||
298 | journal->j_revoke = NULL; | ||
299 | } | ||
300 | |||
301 | |||
302 | #ifdef __KERNEL__ | ||
303 | |||
304 | /* | ||
305 | * journal_revoke: revoke a given buffer_head from the journal. This | ||
306 | * prevents the block from being replayed during recovery if we take a | ||
307 | * crash after this current transaction commits. Any subsequent | ||
308 | * metadata writes of the buffer in this transaction cancel the | ||
309 | * revoke. | ||
310 | * | ||
311 | * Note that this call may block --- it is up to the caller to make | ||
312 | * sure that there are no further calls to journal_write_metadata | ||
313 | * before the revoke is complete. In ext3, this implies calling the | ||
314 | * revoke before clearing the block bitmap when we are deleting | ||
315 | * metadata. | ||
316 | * | ||
317 | * Revoke performs a journal_forget on any buffer_head passed in as a | ||
318 | * parameter, but does _not_ forget the buffer_head if the bh was only | ||
319 | * found implicitly. | ||
320 | * | ||
321 | * bh_in may not be a journalled buffer - it may have come off | ||
322 | * the hash tables without an attached journal_head. | ||
323 | * | ||
324 | * If bh_in is non-zero, journal_revoke() will decrement its b_count | ||
325 | * by one. | ||
326 | */ | ||
327 | |||
328 | int journal_revoke(handle_t *handle, unsigned long blocknr, | ||
329 | struct buffer_head *bh_in) | ||
330 | { | ||
331 | struct buffer_head *bh = NULL; | ||
332 | journal_t *journal; | ||
333 | struct block_device *bdev; | ||
334 | int err; | ||
335 | |||
336 | might_sleep(); | ||
337 | if (bh_in) | ||
338 | BUFFER_TRACE(bh_in, "enter"); | ||
339 | |||
340 | journal = handle->h_transaction->t_journal; | ||
341 | if (!journal_set_features(journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)){ | ||
342 | J_ASSERT (!"Cannot set revoke feature!"); | ||
343 | return -EINVAL; | ||
344 | } | ||
345 | |||
346 | bdev = journal->j_fs_dev; | ||
347 | bh = bh_in; | ||
348 | |||
349 | if (!bh) { | ||
350 | bh = __find_get_block(bdev, blocknr, journal->j_blocksize); | ||
351 | if (bh) | ||
352 | BUFFER_TRACE(bh, "found on hash"); | ||
353 | } | ||
354 | #ifdef JBD_EXPENSIVE_CHECKING | ||
355 | else { | ||
356 | struct buffer_head *bh2; | ||
357 | |||
358 | /* If there is a different buffer_head lying around in | ||
359 | * memory anywhere... */ | ||
360 | bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize); | ||
361 | if (bh2) { | ||
362 | /* ... and it has RevokeValid status... */ | ||
363 | if (bh2 != bh && buffer_revokevalid(bh2)) | ||
364 | /* ...then it better be revoked too, | ||
365 | * since it's illegal to create a revoke | ||
366 | * record against a buffer_head which is | ||
367 | * not marked revoked --- that would | ||
368 | * risk missing a subsequent revoke | ||
369 | * cancel. */ | ||
370 | J_ASSERT_BH(bh2, buffer_revoked(bh2)); | ||
371 | put_bh(bh2); | ||
372 | } | ||
373 | } | ||
374 | #endif | ||
375 | |||
376 | /* We really ought not ever to revoke twice in a row without | ||
377 | first having the revoke cancelled: it's illegal to free a | ||
378 | block twice without allocating it in between! */ | ||
379 | if (bh) { | ||
380 | if (!J_EXPECT_BH(bh, !buffer_revoked(bh), | ||
381 | "inconsistent data on disk")) { | ||
382 | if (!bh_in) | ||
383 | brelse(bh); | ||
384 | return -EIO; | ||
385 | } | ||
386 | set_buffer_revoked(bh); | ||
387 | set_buffer_revokevalid(bh); | ||
388 | if (bh_in) { | ||
389 | BUFFER_TRACE(bh_in, "call journal_forget"); | ||
390 | journal_forget(handle, bh_in); | ||
391 | } else { | ||
392 | BUFFER_TRACE(bh, "call brelse"); | ||
393 | __brelse(bh); | ||
394 | } | ||
395 | } | ||
396 | |||
397 | jbd_debug(2, "insert revoke for block %lu, bh_in=%p\n", blocknr, bh_in); | ||
398 | err = insert_revoke_hash(journal, blocknr, | ||
399 | handle->h_transaction->t_tid); | ||
400 | BUFFER_TRACE(bh_in, "exit"); | ||
401 | return err; | ||
402 | } | ||
403 | |||
404 | /* | ||
405 | * Cancel an outstanding revoke. For use only internally by the | ||
406 | * journaling code (called from journal_get_write_access). | ||
407 | * | ||
408 | * We trust buffer_revoked() on the buffer if the buffer is already | ||
409 | * being journaled: if there is no revoke pending on the buffer, then we | ||
410 | * don't do anything here. | ||
411 | * | ||
412 | * This would break if it were possible for a buffer to be revoked and | ||
413 | * discarded, and then reallocated within the same transaction. In such | ||
414 | * a case we would have lost the revoked bit, but when we arrived here | ||
415 | * the second time we would still have a pending revoke to cancel. So, | ||
416 | * do not trust the Revoked bit on buffers unless RevokeValid is also | ||
417 | * set. | ||
418 | * | ||
419 | * The caller must have the journal locked. | ||
420 | */ | ||
421 | int journal_cancel_revoke(handle_t *handle, struct journal_head *jh) | ||
422 | { | ||
423 | struct jbd_revoke_record_s *record; | ||
424 | journal_t *journal = handle->h_transaction->t_journal; | ||
425 | int need_cancel; | ||
426 | int did_revoke = 0; /* akpm: debug */ | ||
427 | struct buffer_head *bh = jh2bh(jh); | ||
428 | |||
429 | jbd_debug(4, "journal_head %p, cancelling revoke\n", jh); | ||
430 | |||
431 | /* Is the existing Revoke bit valid? If so, we trust it, and | ||
432 | * only perform the full cancel if the revoke bit is set. If | ||
433 | * not, we can't trust the revoke bit, and we need to do the | ||
434 | * full search for a revoke record. */ | ||
435 | if (test_set_buffer_revokevalid(bh)) { | ||
436 | need_cancel = test_clear_buffer_revoked(bh); | ||
437 | } else { | ||
438 | need_cancel = 1; | ||
439 | clear_buffer_revoked(bh); | ||
440 | } | ||
441 | |||
442 | if (need_cancel) { | ||
443 | record = find_revoke_record(journal, bh->b_blocknr); | ||
444 | if (record) { | ||
445 | jbd_debug(4, "cancelled existing revoke on " | ||
446 | "blocknr %llu\n", (unsigned long long)bh->b_blocknr); | ||
447 | spin_lock(&journal->j_revoke_lock); | ||
448 | list_del(&record->hash); | ||
449 | spin_unlock(&journal->j_revoke_lock); | ||
450 | kmem_cache_free(revoke_record_cache, record); | ||
451 | did_revoke = 1; | ||
452 | } | ||
453 | } | ||
454 | |||
455 | #ifdef JBD_EXPENSIVE_CHECKING | ||
456 | /* There better not be one left behind by now! */ | ||
457 | record = find_revoke_record(journal, bh->b_blocknr); | ||
458 | J_ASSERT_JH(jh, record == NULL); | ||
459 | #endif | ||
460 | |||
461 | /* Finally, have we just cleared revoke on an unhashed | ||
462 | * buffer_head? If so, we'd better make sure we clear the | ||
463 | * revoked status on any hashed alias too, otherwise the revoke | ||
464 | * state machine will get very upset later on. */ | ||
465 | if (need_cancel) { | ||
466 | struct buffer_head *bh2; | ||
467 | bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size); | ||
468 | if (bh2) { | ||
469 | if (bh2 != bh) | ||
470 | clear_buffer_revoked(bh2); | ||
471 | __brelse(bh2); | ||
472 | } | ||
473 | } | ||
474 | return did_revoke; | ||
475 | } | ||
476 | |||
477 | /* journal_switch_revoke table select j_revoke for next transaction | ||
478 | * we do not want to suspend any processing until all revokes are | ||
479 | * written -bzzz | ||
480 | */ | ||
481 | void journal_switch_revoke_table(journal_t *journal) | ||
482 | { | ||
483 | int i; | ||
484 | |||
485 | if (journal->j_revoke == journal->j_revoke_table[0]) | ||
486 | journal->j_revoke = journal->j_revoke_table[1]; | ||
487 | else | ||
488 | journal->j_revoke = journal->j_revoke_table[0]; | ||
489 | |||
490 | for (i = 0; i < journal->j_revoke->hash_size; i++) | ||
491 | INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]); | ||
492 | } | ||
493 | |||
494 | /* | ||
495 | * Write revoke records to the journal for all entries in the current | ||
496 | * revoke hash, deleting the entries as we go. | ||
497 | * | ||
498 | * Called with the journal lock held. | ||
499 | */ | ||
500 | |||
501 | void journal_write_revoke_records(journal_t *journal, | ||
502 | transaction_t *transaction) | ||
503 | { | ||
504 | struct journal_head *descriptor; | ||
505 | struct jbd_revoke_record_s *record; | ||
506 | struct jbd_revoke_table_s *revoke; | ||
507 | struct list_head *hash_list; | ||
508 | int i, offset, count; | ||
509 | |||
510 | descriptor = NULL; | ||
511 | offset = 0; | ||
512 | count = 0; | ||
513 | |||
514 | /* select revoke table for committing transaction */ | ||
515 | revoke = journal->j_revoke == journal->j_revoke_table[0] ? | ||
516 | journal->j_revoke_table[1] : journal->j_revoke_table[0]; | ||
517 | |||
518 | for (i = 0; i < revoke->hash_size; i++) { | ||
519 | hash_list = &revoke->hash_table[i]; | ||
520 | |||
521 | while (!list_empty(hash_list)) { | ||
522 | record = (struct jbd_revoke_record_s *) | ||
523 | hash_list->next; | ||
524 | write_one_revoke_record(journal, transaction, | ||
525 | &descriptor, &offset, | ||
526 | record); | ||
527 | count++; | ||
528 | list_del(&record->hash); | ||
529 | kmem_cache_free(revoke_record_cache, record); | ||
530 | } | ||
531 | } | ||
532 | if (descriptor) | ||
533 | flush_descriptor(journal, descriptor, offset); | ||
534 | jbd_debug(1, "Wrote %d revoke records\n", count); | ||
535 | } | ||
536 | |||
537 | /* | ||
538 | * Write out one revoke record. We need to create a new descriptor | ||
539 | * block if the old one is full or if we have not already created one. | ||
540 | */ | ||
541 | |||
542 | static void write_one_revoke_record(journal_t *journal, | ||
543 | transaction_t *transaction, | ||
544 | struct journal_head **descriptorp, | ||
545 | int *offsetp, | ||
546 | struct jbd_revoke_record_s *record) | ||
547 | { | ||
548 | struct journal_head *descriptor; | ||
549 | int offset; | ||
550 | journal_header_t *header; | ||
551 | |||
552 | /* If we are already aborting, this all becomes a noop. We | ||
553 | still need to go round the loop in | ||
554 | journal_write_revoke_records in order to free all of the | ||
555 | revoke records: only the IO to the journal is omitted. */ | ||
556 | if (is_journal_aborted(journal)) | ||
557 | return; | ||
558 | |||
559 | descriptor = *descriptorp; | ||
560 | offset = *offsetp; | ||
561 | |||
562 | /* Make sure we have a descriptor with space left for the record */ | ||
563 | if (descriptor) { | ||
564 | if (offset == journal->j_blocksize) { | ||
565 | flush_descriptor(journal, descriptor, offset); | ||
566 | descriptor = NULL; | ||
567 | } | ||
568 | } | ||
569 | |||
570 | if (!descriptor) { | ||
571 | descriptor = journal_get_descriptor_buffer(journal); | ||
572 | if (!descriptor) | ||
573 | return; | ||
574 | header = (journal_header_t *) &jh2bh(descriptor)->b_data[0]; | ||
575 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | ||
576 | header->h_blocktype = cpu_to_be32(JFS_REVOKE_BLOCK); | ||
577 | header->h_sequence = cpu_to_be32(transaction->t_tid); | ||
578 | |||
579 | /* Record it so that we can wait for IO completion later */ | ||
580 | JBUFFER_TRACE(descriptor, "file as BJ_LogCtl"); | ||
581 | journal_file_buffer(descriptor, transaction, BJ_LogCtl); | ||
582 | |||
583 | offset = sizeof(journal_revoke_header_t); | ||
584 | *descriptorp = descriptor; | ||
585 | } | ||
586 | |||
587 | * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) = | ||
588 | cpu_to_be32(record->blocknr); | ||
589 | offset += 4; | ||
590 | *offsetp = offset; | ||
591 | } | ||
592 | |||
593 | /* | ||
594 | * Flush a revoke descriptor out to the journal. If we are aborting, | ||
595 | * this is a noop; otherwise we are generating a buffer which needs to | ||
596 | * be waited for during commit, so it has to go onto the appropriate | ||
597 | * journal buffer list. | ||
598 | */ | ||
599 | |||
600 | static void flush_descriptor(journal_t *journal, | ||
601 | struct journal_head *descriptor, | ||
602 | int offset) | ||
603 | { | ||
604 | journal_revoke_header_t *header; | ||
605 | struct buffer_head *bh = jh2bh(descriptor); | ||
606 | |||
607 | if (is_journal_aborted(journal)) { | ||
608 | put_bh(bh); | ||
609 | return; | ||
610 | } | ||
611 | |||
612 | header = (journal_revoke_header_t *) jh2bh(descriptor)->b_data; | ||
613 | header->r_count = cpu_to_be32(offset); | ||
614 | set_buffer_jwrite(bh); | ||
615 | BUFFER_TRACE(bh, "write"); | ||
616 | set_buffer_dirty(bh); | ||
617 | ll_rw_block(SWRITE, 1, &bh); | ||
618 | } | ||
619 | #endif | ||
620 | |||
621 | /* | ||
622 | * Revoke support for recovery. | ||
623 | * | ||
624 | * Recovery needs to be able to: | ||
625 | * | ||
626 | * record all revoke records, including the tid of the latest instance | ||
627 | * of each revoke in the journal | ||
628 | * | ||
629 | * check whether a given block in a given transaction should be replayed | ||
630 | * (ie. has not been revoked by a revoke record in that or a subsequent | ||
631 | * transaction) | ||
632 | * | ||
633 | * empty the revoke table after recovery. | ||
634 | */ | ||
635 | |||
636 | /* | ||
637 | * First, setting revoke records. We create a new revoke record for | ||
638 | * every block ever revoked in the log as we scan it for recovery, and | ||
639 | * we update the existing records if we find multiple revokes for a | ||
640 | * single block. | ||
641 | */ | ||
642 | |||
643 | int journal_set_revoke(journal_t *journal, | ||
644 | unsigned long blocknr, | ||
645 | tid_t sequence) | ||
646 | { | ||
647 | struct jbd_revoke_record_s *record; | ||
648 | |||
649 | record = find_revoke_record(journal, blocknr); | ||
650 | if (record) { | ||
651 | /* If we have multiple occurrences, only record the | ||
652 | * latest sequence number in the hashed record */ | ||
653 | if (tid_gt(sequence, record->sequence)) | ||
654 | record->sequence = sequence; | ||
655 | return 0; | ||
656 | } | ||
657 | return insert_revoke_hash(journal, blocknr, sequence); | ||
658 | } | ||
659 | |||
660 | /* | ||
661 | * Test revoke records. For a given block referenced in the log, has | ||
662 | * that block been revoked? A revoke record with a given transaction | ||
663 | * sequence number revokes all blocks in that transaction and earlier | ||
664 | * ones, but later transactions still need replayed. | ||
665 | */ | ||
666 | |||
667 | int journal_test_revoke(journal_t *journal, | ||
668 | unsigned long blocknr, | ||
669 | tid_t sequence) | ||
670 | { | ||
671 | struct jbd_revoke_record_s *record; | ||
672 | |||
673 | record = find_revoke_record(journal, blocknr); | ||
674 | if (!record) | ||
675 | return 0; | ||
676 | if (tid_gt(sequence, record->sequence)) | ||
677 | return 0; | ||
678 | return 1; | ||
679 | } | ||
680 | |||
681 | /* | ||
682 | * Finally, once recovery is over, we need to clear the revoke table so | ||
683 | * that it can be reused by the running filesystem. | ||
684 | */ | ||
685 | |||
686 | void journal_clear_revoke(journal_t *journal) | ||
687 | { | ||
688 | int i; | ||
689 | struct list_head *hash_list; | ||
690 | struct jbd_revoke_record_s *record; | ||
691 | struct jbd_revoke_table_s *revoke; | ||
692 | |||
693 | revoke = journal->j_revoke; | ||
694 | |||
695 | for (i = 0; i < revoke->hash_size; i++) { | ||
696 | hash_list = &revoke->hash_table[i]; | ||
697 | while (!list_empty(hash_list)) { | ||
698 | record = (struct jbd_revoke_record_s*) hash_list->next; | ||
699 | list_del(&record->hash); | ||
700 | kmem_cache_free(revoke_record_cache, record); | ||
701 | } | ||
702 | } | ||
703 | } | ||