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1 | /* |
2 | * linux/fs/jbd2/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 | * Locking rules: |
60 | * We keep two hash tables of revoke records. One hashtable belongs to the |
61 | * running transaction (is pointed to by journal->j_revoke), the other one |
62 | * belongs to the committing transaction. Accesses to the second hash table |
63 | * happen only from the kjournald and no other thread touches this table. Also |
64 | * journal_switch_revoke_table() which switches which hashtable belongs to the |
65 | * running and which to the committing transaction is called only from |
66 | * kjournald. Therefore we need no locks when accessing the hashtable belonging |
67 | * to the committing transaction. |
68 | * |
69 | * All users operating on the hash table belonging to the running transaction |
70 | * have a handle to the transaction. Therefore they are safe from kjournald |
71 | * switching hash tables under them. For operations on the lists of entries in |
72 | * the hash table j_revoke_lock is used. |
73 | * |
74 | * Finally, also replay code uses the hash tables but at this moment no one else |
75 | * can touch them (filesystem isn't mounted yet) and hence no locking is |
76 | * needed. |
77 | */ |
78 | |
79 | #ifndef __KERNEL__ |
80 | #include "jfs_user.h" |
81 | #else |
82 | #include <linux/time.h> |
83 | #include <linux/fs.h> |
84 | #include <linux/jbd2.h> |
85 | #include <linux/errno.h> |
86 | #include <linux/slab.h> |
87 | #include <linux/list.h> |
88 | #include <linux/init.h> |
89 | #include <linux/bio.h> |
90 | #endif |
91 | #include <linux/log2.h> |
92 | |
93 | static struct kmem_cache *jbd2_revoke_record_cache; |
94 | static struct kmem_cache *jbd2_revoke_table_cache; |
95 | |
96 | /* Each revoke record represents one single revoked block. During |
97 | journal replay, this involves recording the transaction ID of the |
98 | last transaction to revoke this block. */ |
99 | |
100 | struct jbd2_revoke_record_s |
101 | { |
102 | struct list_head hash; |
103 | tid_t sequence; /* Used for recovery only */ |
104 | unsigned long long blocknr; |
105 | }; |
106 | |
107 | |
108 | /* The revoke table is just a simple hash table of revoke records. */ |
109 | struct jbd2_revoke_table_s |
110 | { |
111 | /* It is conceivable that we might want a larger hash table |
112 | * for recovery. Must be a power of two. */ |
113 | int hash_size; |
114 | int hash_shift; |
115 | struct list_head *hash_table; |
116 | }; |
117 | |
118 | |
119 | #ifdef __KERNEL__ |
120 | static void write_one_revoke_record(journal_t *, transaction_t *, |
121 | struct journal_head **, int *, |
122 | struct jbd2_revoke_record_s *, int); |
123 | static void flush_descriptor(journal_t *, struct journal_head *, int, int); |
124 | #endif |
125 | |
126 | /* Utility functions to maintain the revoke table */ |
127 | |
128 | /* Borrowed from buffer.c: this is a tried and tested block hash function */ |
129 | static inline int hash(journal_t *journal, unsigned long long block) |
130 | { |
131 | struct jbd2_revoke_table_s *table = journal->j_revoke; |
132 | int hash_shift = table->hash_shift; |
133 | int hash = (int)block ^ (int)((block >> 31) >> 1); |
134 | |
135 | return ((hash << (hash_shift - 6)) ^ |
136 | (hash >> 13) ^ |
137 | (hash << (hash_shift - 12))) & (table->hash_size - 1); |
138 | } |
139 | |
140 | static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr, |
141 | tid_t seq) |
142 | { |
143 | struct list_head *hash_list; |
144 | struct jbd2_revoke_record_s *record; |
145 | |
146 | repeat: |
147 | record = kmem_cache_alloc(jbd2_revoke_record_cache, GFP_NOFS); |
148 | if (!record) |
149 | goto oom; |
150 | |
151 | record->sequence = seq; |
152 | record->blocknr = blocknr; |
153 | hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; |
154 | spin_lock(&journal->j_revoke_lock); |
155 | list_add(&record->hash, hash_list); |
156 | spin_unlock(&journal->j_revoke_lock); |
157 | return 0; |
158 | |
159 | oom: |
160 | if (!journal_oom_retry) |
161 | return -ENOMEM; |
162 | jbd_debug(1, "ENOMEM in %s, retrying\n", __func__); |
163 | yield(); |
164 | goto repeat; |
165 | } |
166 | |
167 | /* Find a revoke record in the journal's hash table. */ |
168 | |
169 | static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal, |
170 | unsigned long long blocknr) |
171 | { |
172 | struct list_head *hash_list; |
173 | struct jbd2_revoke_record_s *record; |
174 | |
175 | hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; |
176 | |
177 | spin_lock(&journal->j_revoke_lock); |
178 | record = (struct jbd2_revoke_record_s *) hash_list->next; |
179 | while (&(record->hash) != hash_list) { |
180 | if (record->blocknr == blocknr) { |
181 | spin_unlock(&journal->j_revoke_lock); |
182 | return record; |
183 | } |
184 | record = (struct jbd2_revoke_record_s *) record->hash.next; |
185 | } |
186 | spin_unlock(&journal->j_revoke_lock); |
187 | return NULL; |
188 | } |
189 | |
190 | void jbd2_journal_destroy_revoke_caches(void) |
191 | { |
192 | if (jbd2_revoke_record_cache) { |
193 | kmem_cache_destroy(jbd2_revoke_record_cache); |
194 | jbd2_revoke_record_cache = NULL; |
195 | } |
196 | if (jbd2_revoke_table_cache) { |
197 | kmem_cache_destroy(jbd2_revoke_table_cache); |
198 | jbd2_revoke_table_cache = NULL; |
199 | } |
200 | } |
201 | |
202 | int __init jbd2_journal_init_revoke_caches(void) |
203 | { |
204 | J_ASSERT(!jbd2_revoke_record_cache); |
205 | J_ASSERT(!jbd2_revoke_table_cache); |
206 | |
207 | jbd2_revoke_record_cache = kmem_cache_create("jbd2_revoke_record", |
208 | sizeof(struct jbd2_revoke_record_s), |
209 | 0, |
210 | SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY, |
211 | NULL); |
212 | if (!jbd2_revoke_record_cache) |
213 | goto record_cache_failure; |
214 | |
215 | jbd2_revoke_table_cache = kmem_cache_create("jbd2_revoke_table", |
216 | sizeof(struct jbd2_revoke_table_s), |
217 | 0, SLAB_TEMPORARY, NULL); |
218 | if (!jbd2_revoke_table_cache) |
219 | goto table_cache_failure; |
220 | return 0; |
221 | table_cache_failure: |
222 | jbd2_journal_destroy_revoke_caches(); |
223 | record_cache_failure: |
224 | return -ENOMEM; |
225 | } |
226 | |
227 | static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size) |
228 | { |
229 | int shift = 0; |
230 | int tmp = hash_size; |
231 | struct jbd2_revoke_table_s *table; |
232 | |
233 | table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL); |
234 | if (!table) |
235 | goto out; |
236 | |
237 | while((tmp >>= 1UL) != 0UL) |
238 | shift++; |
239 | |
240 | table->hash_size = hash_size; |
241 | table->hash_shift = shift; |
242 | table->hash_table = |
243 | kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); |
244 | if (!table->hash_table) { |
245 | kmem_cache_free(jbd2_revoke_table_cache, table); |
246 | table = NULL; |
247 | goto out; |
248 | } |
249 | |
250 | for (tmp = 0; tmp < hash_size; tmp++) |
251 | INIT_LIST_HEAD(&table->hash_table[tmp]); |
252 | |
253 | out: |
254 | return table; |
255 | } |
256 | |
257 | static void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table) |
258 | { |
259 | int i; |
260 | struct list_head *hash_list; |
261 | |
262 | for (i = 0; i < table->hash_size; i++) { |
263 | hash_list = &table->hash_table[i]; |
264 | J_ASSERT(list_empty(hash_list)); |
265 | } |
266 | |
267 | kfree(table->hash_table); |
268 | kmem_cache_free(jbd2_revoke_table_cache, table); |
269 | } |
270 | |
271 | /* Initialise the revoke table for a given journal to a given size. */ |
272 | int jbd2_journal_init_revoke(journal_t *journal, int hash_size) |
273 | { |
274 | J_ASSERT(journal->j_revoke_table[0] == NULL); |
275 | J_ASSERT(is_power_of_2(hash_size)); |
276 | |
277 | journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size); |
278 | if (!journal->j_revoke_table[0]) |
279 | goto fail0; |
280 | |
281 | journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size); |
282 | if (!journal->j_revoke_table[1]) |
283 | goto fail1; |
284 | |
285 | journal->j_revoke = journal->j_revoke_table[1]; |
286 | |
287 | spin_lock_init(&journal->j_revoke_lock); |
288 | |
289 | return 0; |
290 | |
291 | fail1: |
292 | jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]); |
293 | fail0: |
294 | return -ENOMEM; |
295 | } |
296 | |
297 | /* Destroy a journal's revoke table. The table must already be empty! */ |
298 | void jbd2_journal_destroy_revoke(journal_t *journal) |
299 | { |
300 | journal->j_revoke = NULL; |
301 | if (journal->j_revoke_table[0]) |
302 | jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]); |
303 | if (journal->j_revoke_table[1]) |
304 | jbd2_journal_destroy_revoke_table(journal->j_revoke_table[1]); |
305 | } |
306 | |
307 | |
308 | #ifdef __KERNEL__ |
309 | |
310 | /* |
311 | * jbd2_journal_revoke: revoke a given buffer_head from the journal. This |
312 | * prevents the block from being replayed during recovery if we take a |
313 | * crash after this current transaction commits. Any subsequent |
314 | * metadata writes of the buffer in this transaction cancel the |
315 | * revoke. |
316 | * |
317 | * Note that this call may block --- it is up to the caller to make |
318 | * sure that there are no further calls to journal_write_metadata |
319 | * before the revoke is complete. In ext3, this implies calling the |
320 | * revoke before clearing the block bitmap when we are deleting |
321 | * metadata. |
322 | * |
323 | * Revoke performs a jbd2_journal_forget on any buffer_head passed in as a |
324 | * parameter, but does _not_ forget the buffer_head if the bh was only |
325 | * found implicitly. |
326 | * |
327 | * bh_in may not be a journalled buffer - it may have come off |
328 | * the hash tables without an attached journal_head. |
329 | * |
330 | * If bh_in is non-zero, jbd2_journal_revoke() will decrement its b_count |
331 | * by one. |
332 | */ |
333 | |
334 | int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr, |
335 | struct buffer_head *bh_in) |
336 | { |
337 | struct buffer_head *bh = NULL; |
338 | journal_t *journal; |
339 | struct block_device *bdev; |
340 | int err; |
341 | |
342 | might_sleep(); |
343 | if (bh_in) |
344 | BUFFER_TRACE(bh_in, "enter"); |
345 | |
346 | journal = handle->h_transaction->t_journal; |
347 | if (!jbd2_journal_set_features(journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)){ |
348 | J_ASSERT (!"Cannot set revoke feature!"); |
349 | return -EINVAL; |
350 | } |
351 | |
352 | bdev = journal->j_fs_dev; |
353 | bh = bh_in; |
354 | |
355 | if (!bh) { |
356 | bh = __find_get_block(bdev, blocknr, journal->j_blocksize); |
357 | if (bh) |
358 | BUFFER_TRACE(bh, "found on hash"); |
359 | } |
360 | #ifdef JBD2_EXPENSIVE_CHECKING |
361 | else { |
362 | struct buffer_head *bh2; |
363 | |
364 | /* If there is a different buffer_head lying around in |
365 | * memory anywhere... */ |
366 | bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize); |
367 | if (bh2) { |
368 | /* ... and it has RevokeValid status... */ |
369 | if (bh2 != bh && buffer_revokevalid(bh2)) |
370 | /* ...then it better be revoked too, |
371 | * since it's illegal to create a revoke |
372 | * record against a buffer_head which is |
373 | * not marked revoked --- that would |
374 | * risk missing a subsequent revoke |
375 | * cancel. */ |
376 | J_ASSERT_BH(bh2, buffer_revoked(bh2)); |
377 | put_bh(bh2); |
378 | } |
379 | } |
380 | #endif |
381 | |
382 | /* We really ought not ever to revoke twice in a row without |
383 | first having the revoke cancelled: it's illegal to free a |
384 | block twice without allocating it in between! */ |
385 | if (bh) { |
386 | if (!J_EXPECT_BH(bh, !buffer_revoked(bh), |
387 | "inconsistent data on disk")) { |
388 | if (!bh_in) |
389 | brelse(bh); |
390 | return -EIO; |
391 | } |
392 | set_buffer_revoked(bh); |
393 | set_buffer_revokevalid(bh); |
394 | if (bh_in) { |
395 | BUFFER_TRACE(bh_in, "call jbd2_journal_forget"); |
396 | jbd2_journal_forget(handle, bh_in); |
397 | } else { |
398 | BUFFER_TRACE(bh, "call brelse"); |
399 | __brelse(bh); |
400 | } |
401 | } |
402 | |
403 | jbd_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in); |
404 | err = insert_revoke_hash(journal, blocknr, |
405 | handle->h_transaction->t_tid); |
406 | BUFFER_TRACE(bh_in, "exit"); |
407 | return err; |
408 | } |
409 | |
410 | /* |
411 | * Cancel an outstanding revoke. For use only internally by the |
412 | * journaling code (called from jbd2_journal_get_write_access). |
413 | * |
414 | * We trust buffer_revoked() on the buffer if the buffer is already |
415 | * being journaled: if there is no revoke pending on the buffer, then we |
416 | * don't do anything here. |
417 | * |
418 | * This would break if it were possible for a buffer to be revoked and |
419 | * discarded, and then reallocated within the same transaction. In such |
420 | * a case we would have lost the revoked bit, but when we arrived here |
421 | * the second time we would still have a pending revoke to cancel. So, |
422 | * do not trust the Revoked bit on buffers unless RevokeValid is also |
423 | * set. |
424 | */ |
425 | int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh) |
426 | { |
427 | struct jbd2_revoke_record_s *record; |
428 | journal_t *journal = handle->h_transaction->t_journal; |
429 | int need_cancel; |
430 | int did_revoke = 0; /* akpm: debug */ |
431 | struct buffer_head *bh = jh2bh(jh); |
432 | |
433 | jbd_debug(4, "journal_head %p, cancelling revoke\n", jh); |
434 | |
435 | /* Is the existing Revoke bit valid? If so, we trust it, and |
436 | * only perform the full cancel if the revoke bit is set. If |
437 | * not, we can't trust the revoke bit, and we need to do the |
438 | * full search for a revoke record. */ |
439 | if (test_set_buffer_revokevalid(bh)) { |
440 | need_cancel = test_clear_buffer_revoked(bh); |
441 | } else { |
442 | need_cancel = 1; |
443 | clear_buffer_revoked(bh); |
444 | } |
445 | |
446 | if (need_cancel) { |
447 | record = find_revoke_record(journal, bh->b_blocknr); |
448 | if (record) { |
449 | jbd_debug(4, "cancelled existing revoke on " |
450 | "blocknr %llu\n", (unsigned long long)bh->b_blocknr); |
451 | spin_lock(&journal->j_revoke_lock); |
452 | list_del(&record->hash); |
453 | spin_unlock(&journal->j_revoke_lock); |
454 | kmem_cache_free(jbd2_revoke_record_cache, record); |
455 | did_revoke = 1; |
456 | } |
457 | } |
458 | |
459 | #ifdef JBD2_EXPENSIVE_CHECKING |
460 | /* There better not be one left behind by now! */ |
461 | record = find_revoke_record(journal, bh->b_blocknr); |
462 | J_ASSERT_JH(jh, record == NULL); |
463 | #endif |
464 | |
465 | /* Finally, have we just cleared revoke on an unhashed |
466 | * buffer_head? If so, we'd better make sure we clear the |
467 | * revoked status on any hashed alias too, otherwise the revoke |
468 | * state machine will get very upset later on. */ |
469 | if (need_cancel) { |
470 | struct buffer_head *bh2; |
471 | bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size); |
472 | if (bh2) { |
473 | if (bh2 != bh) |
474 | clear_buffer_revoked(bh2); |
475 | __brelse(bh2); |
476 | } |
477 | } |
478 | return did_revoke; |
479 | } |
480 | |
481 | /* journal_switch_revoke table select j_revoke for next transaction |
482 | * we do not want to suspend any processing until all revokes are |
483 | * written -bzzz |
484 | */ |
485 | void jbd2_journal_switch_revoke_table(journal_t *journal) |
486 | { |
487 | int i; |
488 | |
489 | if (journal->j_revoke == journal->j_revoke_table[0]) |
490 | journal->j_revoke = journal->j_revoke_table[1]; |
491 | else |
492 | journal->j_revoke = journal->j_revoke_table[0]; |
493 | |
494 | for (i = 0; i < journal->j_revoke->hash_size; i++) |
495 | INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]); |
496 | } |
497 | |
498 | /* |
499 | * Write revoke records to the journal for all entries in the current |
500 | * revoke hash, deleting the entries as we go. |
501 | */ |
502 | void jbd2_journal_write_revoke_records(journal_t *journal, |
503 | transaction_t *transaction, |
504 | int write_op) |
505 | { |
506 | struct journal_head *descriptor; |
507 | struct jbd2_revoke_record_s *record; |
508 | struct jbd2_revoke_table_s *revoke; |
509 | struct list_head *hash_list; |
510 | int i, offset, count; |
511 | |
512 | descriptor = NULL; |
513 | offset = 0; |
514 | count = 0; |
515 | |
516 | /* select revoke table for committing transaction */ |
517 | revoke = journal->j_revoke == journal->j_revoke_table[0] ? |
518 | journal->j_revoke_table[1] : journal->j_revoke_table[0]; |
519 | |
520 | for (i = 0; i < revoke->hash_size; i++) { |
521 | hash_list = &revoke->hash_table[i]; |
522 | |
523 | while (!list_empty(hash_list)) { |
524 | record = (struct jbd2_revoke_record_s *) |
525 | hash_list->next; |
526 | write_one_revoke_record(journal, transaction, |
527 | &descriptor, &offset, |
528 | record, write_op); |
529 | count++; |
530 | list_del(&record->hash); |
531 | kmem_cache_free(jbd2_revoke_record_cache, record); |
532 | } |
533 | } |
534 | if (descriptor) |
535 | flush_descriptor(journal, descriptor, offset, write_op); |
536 | jbd_debug(1, "Wrote %d revoke records\n", count); |
537 | } |
538 | |
539 | /* |
540 | * Write out one revoke record. We need to create a new descriptor |
541 | * block if the old one is full or if we have not already created one. |
542 | */ |
543 | |
544 | static void write_one_revoke_record(journal_t *journal, |
545 | transaction_t *transaction, |
546 | struct journal_head **descriptorp, |
547 | int *offsetp, |
548 | struct jbd2_revoke_record_s *record, |
549 | int write_op) |
550 | { |
551 | struct journal_head *descriptor; |
552 | int offset; |
553 | journal_header_t *header; |
554 | |
555 | /* If we are already aborting, this all becomes a noop. We |
556 | still need to go round the loop in |
557 | jbd2_journal_write_revoke_records in order to free all of the |
558 | revoke records: only the IO to the journal is omitted. */ |
559 | if (is_journal_aborted(journal)) |
560 | return; |
561 | |
562 | descriptor = *descriptorp; |
563 | offset = *offsetp; |
564 | |
565 | /* Make sure we have a descriptor with space left for the record */ |
566 | if (descriptor) { |
567 | if (offset == journal->j_blocksize) { |
568 | flush_descriptor(journal, descriptor, offset, write_op); |
569 | descriptor = NULL; |
570 | } |
571 | } |
572 | |
573 | if (!descriptor) { |
574 | descriptor = jbd2_journal_get_descriptor_buffer(journal); |
575 | if (!descriptor) |
576 | return; |
577 | header = (journal_header_t *) &jh2bh(descriptor)->b_data[0]; |
578 | header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); |
579 | header->h_blocktype = cpu_to_be32(JBD2_REVOKE_BLOCK); |
580 | header->h_sequence = cpu_to_be32(transaction->t_tid); |
581 | |
582 | /* Record it so that we can wait for IO completion later */ |
583 | JBUFFER_TRACE(descriptor, "file as BJ_LogCtl"); |
584 | jbd2_journal_file_buffer(descriptor, transaction, BJ_LogCtl); |
585 | |
586 | offset = sizeof(jbd2_journal_revoke_header_t); |
587 | *descriptorp = descriptor; |
588 | } |
589 | |
590 | if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) { |
591 | * ((__be64 *)(&jh2bh(descriptor)->b_data[offset])) = |
592 | cpu_to_be64(record->blocknr); |
593 | offset += 8; |
594 | |
595 | } else { |
596 | * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) = |
597 | cpu_to_be32(record->blocknr); |
598 | offset += 4; |
599 | } |
600 | |
601 | *offsetp = offset; |
602 | } |
603 | |
604 | /* |
605 | * Flush a revoke descriptor out to the journal. If we are aborting, |
606 | * this is a noop; otherwise we are generating a buffer which needs to |
607 | * be waited for during commit, so it has to go onto the appropriate |
608 | * journal buffer list. |
609 | */ |
610 | |
611 | static void flush_descriptor(journal_t *journal, |
612 | struct journal_head *descriptor, |
613 | int offset, int write_op) |
614 | { |
615 | jbd2_journal_revoke_header_t *header; |
616 | struct buffer_head *bh = jh2bh(descriptor); |
617 | |
618 | if (is_journal_aborted(journal)) { |
619 | put_bh(bh); |
620 | return; |
621 | } |
622 | |
623 | header = (jbd2_journal_revoke_header_t *) jh2bh(descriptor)->b_data; |
624 | header->r_count = cpu_to_be32(offset); |
625 | set_buffer_jwrite(bh); |
626 | BUFFER_TRACE(bh, "write"); |
627 | set_buffer_dirty(bh); |
628 | write_dirty_buffer(bh, write_op); |
629 | } |
630 | #endif |
631 | |
632 | /* |
633 | * Revoke support for recovery. |
634 | * |
635 | * Recovery needs to be able to: |
636 | * |
637 | * record all revoke records, including the tid of the latest instance |
638 | * of each revoke in the journal |
639 | * |
640 | * check whether a given block in a given transaction should be replayed |
641 | * (ie. has not been revoked by a revoke record in that or a subsequent |
642 | * transaction) |
643 | * |
644 | * empty the revoke table after recovery. |
645 | */ |
646 | |
647 | /* |
648 | * First, setting revoke records. We create a new revoke record for |
649 | * every block ever revoked in the log as we scan it for recovery, and |
650 | * we update the existing records if we find multiple revokes for a |
651 | * single block. |
652 | */ |
653 | |
654 | int jbd2_journal_set_revoke(journal_t *journal, |
655 | unsigned long long blocknr, |
656 | tid_t sequence) |
657 | { |
658 | struct jbd2_revoke_record_s *record; |
659 | |
660 | record = find_revoke_record(journal, blocknr); |
661 | if (record) { |
662 | /* If we have multiple occurrences, only record the |
663 | * latest sequence number in the hashed record */ |
664 | if (tid_gt(sequence, record->sequence)) |
665 | record->sequence = sequence; |
666 | return 0; |
667 | } |
668 | return insert_revoke_hash(journal, blocknr, sequence); |
669 | } |
670 | |
671 | /* |
672 | * Test revoke records. For a given block referenced in the log, has |
673 | * that block been revoked? A revoke record with a given transaction |
674 | * sequence number revokes all blocks in that transaction and earlier |
675 | * ones, but later transactions still need replayed. |
676 | */ |
677 | |
678 | int jbd2_journal_test_revoke(journal_t *journal, |
679 | unsigned long long blocknr, |
680 | tid_t sequence) |
681 | { |
682 | struct jbd2_revoke_record_s *record; |
683 | |
684 | record = find_revoke_record(journal, blocknr); |
685 | if (!record) |
686 | return 0; |
687 | if (tid_gt(sequence, record->sequence)) |
688 | return 0; |
689 | return 1; |
690 | } |
691 | |
692 | /* |
693 | * Finally, once recovery is over, we need to clear the revoke table so |
694 | * that it can be reused by the running filesystem. |
695 | */ |
696 | |
697 | void jbd2_journal_clear_revoke(journal_t *journal) |
698 | { |
699 | int i; |
700 | struct list_head *hash_list; |
701 | struct jbd2_revoke_record_s *record; |
702 | struct jbd2_revoke_table_s *revoke; |
703 | |
704 | revoke = journal->j_revoke; |
705 | |
706 | for (i = 0; i < revoke->hash_size; i++) { |
707 | hash_list = &revoke->hash_table[i]; |
708 | while (!list_empty(hash_list)) { |
709 | record = (struct jbd2_revoke_record_s*) hash_list->next; |
710 | list_del(&record->hash); |
711 | kmem_cache_free(jbd2_revoke_record_cache, record); |
712 | } |
713 | } |
714 | } |
715 |
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