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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/revoke.c
Mingming Caoae6ddcc2006-09-27 01:49:27 -07003 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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:
Mingming Caoae6ddcc2006-09-27 01:49:27 -070018 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * + Commit: during commit we write the entire list of the current
20 * transaction's revoked blocks to the journal
Mingming Caoae6ddcc2006-09-27 01:49:27 -070021 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 * + 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:
Mingming Caoae6ddcc2006-09-27 01:49:27 -070032 * The desired end result is the journaling of the new block, so we
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 * 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 *
Mingming Caoae6ddcc2006-09-27 01:49:27 -070044 * Block is revoked and then written as data:
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 * 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:
Mingming Caoae6ddcc2006-09-27 01:49:27 -070057 * buffer has been revoked.
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 */
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
73static kmem_cache_t *revoke_record_cache;
74static 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -070080struct jbd_revoke_record_s
Linus Torvalds1da177e2005-04-16 15:20:36 -070081{
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. */
89struct 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. */
Mingming Caoae6ddcc2006-09-27 01:49:27 -070093 int hash_size;
94 int hash_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 struct list_head *hash_table;
96};
97
98
99#ifdef __KERNEL__
100static void write_one_revoke_record(journal_t *, transaction_t *,
101 struct journal_head **, int *,
102 struct jbd_revoke_record_s *);
103static 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 */
109static 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
Adrian Bunk022a4a72005-09-06 15:16:41 -0700119static int insert_revoke_hash(journal_t *journal, unsigned long blocknr,
120 tid_t seq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121{
122 struct list_head *hash_list;
123 struct jbd_revoke_record_s *record;
124
125repeat:
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
138oom:
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
148static 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
169int __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
188void 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
198int 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
268void 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700304/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 * 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700309 * revoke.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 *
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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700315 * metadata.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 *
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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700319 * found implicitly.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 *
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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700328int journal_revoke(handle_t *handle, unsigned long blocknr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 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 */
421int 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 */
481void 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700490 for (i = 0; i < journal->j_revoke->hash_size; i++)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700501void journal_write_revoke_records(journal_t *journal,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700510 descriptor = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 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)) {
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700522 record = (struct jbd_revoke_record_s *)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 hash_list->next;
524 write_one_revoke_record(journal, transaction,
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700525 &descriptor, &offset,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700537/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 * Write out one revoke record. We need to create a new descriptor
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700539 * block if the old one is full or if we have not already created one.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 */
541
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700542static void write_one_revoke_record(journal_t *journal,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 transaction_t *transaction,
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700544 struct journal_head **descriptorp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700587 * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 cpu_to_be32(record->blocknr);
589 offset += 4;
590 *offsetp = offset;
591}
592
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700593/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 * 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700600static void flush_descriptor(journal_t *journal,
601 struct journal_head *descriptor,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 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);
Jan Kara26707692005-09-06 15:19:12 -0700617 ll_rw_block(SWRITE, 1, &bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618}
619#endif
620
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700621/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 * 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)
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700632 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 * 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700640 * single block.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 */
642
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700643int journal_set_revoke(journal_t *journal,
644 unsigned long blocknr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 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;
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700656 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 return insert_revoke_hash(journal, blocknr, sequence);
658}
659
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700660/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 * 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
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700667int journal_test_revoke(journal_t *journal,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 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
686void 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}