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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Kleine-König58862692007-05-09 07:51:49 +02002 * linux/fs/jbd/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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070069#include <linux/init.h>
70#endif
vignesh babuf4823942007-07-15 23:41:17 -070071#include <linux/log2.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
Christoph Lametere18b8902006-12-06 20:33:20 -080073static struct kmem_cache *revoke_record_cache;
74static struct kmem_cache *revoke_table_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
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;
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700141 jbd_debug(1, "ENOMEM in %s, retrying\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 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
Duane Griffin1984bb72008-07-25 01:46:21 -0700169void journal_destroy_revoke_caches(void)
170{
171 if (revoke_record_cache) {
172 kmem_cache_destroy(revoke_record_cache);
173 revoke_record_cache = NULL;
174 }
175 if (revoke_table_cache) {
176 kmem_cache_destroy(revoke_table_cache);
177 revoke_table_cache = NULL;
178 }
179}
180
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181int __init journal_init_revoke_caches(void)
182{
Duane Griffin1984bb72008-07-25 01:46:21 -0700183 J_ASSERT(!revoke_record_cache);
184 J_ASSERT(!revoke_table_cache);
185
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 revoke_record_cache = kmem_cache_create("revoke_record",
187 sizeof(struct jbd_revoke_record_s),
Mel Gormane12ba742007-10-16 01:25:52 -0700188 0,
189 SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
190 NULL);
Al Viro1076d172008-03-29 03:07:18 +0000191 if (!revoke_record_cache)
Duane Griffin1984bb72008-07-25 01:46:21 -0700192 goto record_cache_failure;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
194 revoke_table_cache = kmem_cache_create("revoke_table",
195 sizeof(struct jbd_revoke_table_s),
Mel Gormane12ba742007-10-16 01:25:52 -0700196 0, SLAB_TEMPORARY, NULL);
Duane Griffin1984bb72008-07-25 01:46:21 -0700197 if (!revoke_table_cache)
198 goto table_cache_failure;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
Duane Griffin1984bb72008-07-25 01:46:21 -0700200 return 0;
201
202table_cache_failure:
203 journal_destroy_revoke_caches();
204record_cache_failure:
205 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206}
207
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700208static struct jbd_revoke_table_s *journal_init_revoke_table(int hash_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700210 int shift = 0;
211 int tmp = hash_size;
212 struct jbd_revoke_table_s *table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700214 table = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL);
215 if (!table)
216 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 while((tmp >>= 1UL) != 0UL)
219 shift++;
220
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700221 table->hash_size = hash_size;
222 table->hash_shift = shift;
223 table->hash_table =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL);
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700225 if (!table->hash_table) {
226 kmem_cache_free(revoke_table_cache, table);
227 table = NULL;
228 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 }
230
231 for (tmp = 0; tmp < hash_size; tmp++)
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700232 INIT_LIST_HEAD(&table->hash_table[tmp]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700234out:
235 return table;
236}
237
238static void journal_destroy_revoke_table(struct jbd_revoke_table_s *table)
239{
240 int i;
241 struct list_head *hash_list;
242
243 for (i = 0; i < table->hash_size; i++) {
244 hash_list = &table->hash_table[i];
245 J_ASSERT(list_empty(hash_list));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 }
247
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700248 kfree(table->hash_table);
249 kmem_cache_free(revoke_table_cache, table);
250}
251
252/* Initialise the revoke table for a given journal to a given size. */
253int journal_init_revoke(journal_t *journal, int hash_size)
254{
255 J_ASSERT(journal->j_revoke_table[0] == NULL);
256 J_ASSERT(is_power_of_2(hash_size));
257
258 journal->j_revoke_table[0] = journal_init_revoke_table(hash_size);
259 if (!journal->j_revoke_table[0])
260 goto fail0;
261
262 journal->j_revoke_table[1] = journal_init_revoke_table(hash_size);
263 if (!journal->j_revoke_table[1])
264 goto fail1;
265
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 journal->j_revoke = journal->j_revoke_table[1];
267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 spin_lock_init(&journal->j_revoke_lock);
269
270 return 0;
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700271
272fail1:
273 journal_destroy_revoke_table(journal->j_revoke_table[0]);
274fail0:
275 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276}
277
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700278/* Destroy a journal's revoke table. The table must already be empty! */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279void journal_destroy_revoke(journal_t *journal)
280{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 journal->j_revoke = NULL;
Duane Griffinf4d79ca2008-07-25 01:46:20 -0700282 if (journal->j_revoke_table[0])
283 journal_destroy_revoke_table(journal->j_revoke_table[0]);
284 if (journal->j_revoke_table[1])
285 journal_destroy_revoke_table(journal->j_revoke_table[1]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286}
287
288
289#ifdef __KERNEL__
290
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700291/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 * journal_revoke: revoke a given buffer_head from the journal. This
293 * prevents the block from being replayed during recovery if we take a
294 * crash after this current transaction commits. Any subsequent
295 * metadata writes of the buffer in this transaction cancel the
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700296 * revoke.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 *
298 * Note that this call may block --- it is up to the caller to make
299 * sure that there are no further calls to journal_write_metadata
300 * before the revoke is complete. In ext3, this implies calling the
301 * revoke before clearing the block bitmap when we are deleting
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700302 * metadata.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 *
304 * Revoke performs a journal_forget on any buffer_head passed in as a
305 * parameter, but does _not_ forget the buffer_head if the bh was only
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700306 * found implicitly.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 *
308 * bh_in may not be a journalled buffer - it may have come off
309 * the hash tables without an attached journal_head.
310 *
311 * If bh_in is non-zero, journal_revoke() will decrement its b_count
312 * by one.
313 */
314
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700315int journal_revoke(handle_t *handle, unsigned long blocknr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 struct buffer_head *bh_in)
317{
318 struct buffer_head *bh = NULL;
319 journal_t *journal;
320 struct block_device *bdev;
321 int err;
322
323 might_sleep();
324 if (bh_in)
325 BUFFER_TRACE(bh_in, "enter");
326
327 journal = handle->h_transaction->t_journal;
328 if (!journal_set_features(journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)){
329 J_ASSERT (!"Cannot set revoke feature!");
330 return -EINVAL;
331 }
332
333 bdev = journal->j_fs_dev;
334 bh = bh_in;
335
336 if (!bh) {
337 bh = __find_get_block(bdev, blocknr, journal->j_blocksize);
338 if (bh)
339 BUFFER_TRACE(bh, "found on hash");
340 }
341#ifdef JBD_EXPENSIVE_CHECKING
342 else {
343 struct buffer_head *bh2;
344
345 /* If there is a different buffer_head lying around in
346 * memory anywhere... */
347 bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize);
348 if (bh2) {
349 /* ... and it has RevokeValid status... */
350 if (bh2 != bh && buffer_revokevalid(bh2))
351 /* ...then it better be revoked too,
352 * since it's illegal to create a revoke
353 * record against a buffer_head which is
354 * not marked revoked --- that would
355 * risk missing a subsequent revoke
356 * cancel. */
357 J_ASSERT_BH(bh2, buffer_revoked(bh2));
358 put_bh(bh2);
359 }
360 }
361#endif
362
363 /* We really ought not ever to revoke twice in a row without
364 first having the revoke cancelled: it's illegal to free a
365 block twice without allocating it in between! */
366 if (bh) {
367 if (!J_EXPECT_BH(bh, !buffer_revoked(bh),
368 "inconsistent data on disk")) {
369 if (!bh_in)
370 brelse(bh);
371 return -EIO;
372 }
373 set_buffer_revoked(bh);
374 set_buffer_revokevalid(bh);
375 if (bh_in) {
376 BUFFER_TRACE(bh_in, "call journal_forget");
377 journal_forget(handle, bh_in);
378 } else {
379 BUFFER_TRACE(bh, "call brelse");
380 __brelse(bh);
381 }
382 }
383
384 jbd_debug(2, "insert revoke for block %lu, bh_in=%p\n", blocknr, bh_in);
385 err = insert_revoke_hash(journal, blocknr,
386 handle->h_transaction->t_tid);
387 BUFFER_TRACE(bh_in, "exit");
388 return err;
389}
390
391/*
392 * Cancel an outstanding revoke. For use only internally by the
393 * journaling code (called from journal_get_write_access).
394 *
395 * We trust buffer_revoked() on the buffer if the buffer is already
396 * being journaled: if there is no revoke pending on the buffer, then we
397 * don't do anything here.
398 *
399 * This would break if it were possible for a buffer to be revoked and
400 * discarded, and then reallocated within the same transaction. In such
401 * a case we would have lost the revoked bit, but when we arrived here
402 * the second time we would still have a pending revoke to cancel. So,
403 * do not trust the Revoked bit on buffers unless RevokeValid is also
404 * set.
405 *
406 * The caller must have the journal locked.
407 */
408int journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
409{
410 struct jbd_revoke_record_s *record;
411 journal_t *journal = handle->h_transaction->t_journal;
412 int need_cancel;
413 int did_revoke = 0; /* akpm: debug */
414 struct buffer_head *bh = jh2bh(jh);
415
416 jbd_debug(4, "journal_head %p, cancelling revoke\n", jh);
417
418 /* Is the existing Revoke bit valid? If so, we trust it, and
419 * only perform the full cancel if the revoke bit is set. If
420 * not, we can't trust the revoke bit, and we need to do the
421 * full search for a revoke record. */
422 if (test_set_buffer_revokevalid(bh)) {
423 need_cancel = test_clear_buffer_revoked(bh);
424 } else {
425 need_cancel = 1;
426 clear_buffer_revoked(bh);
427 }
428
429 if (need_cancel) {
430 record = find_revoke_record(journal, bh->b_blocknr);
431 if (record) {
432 jbd_debug(4, "cancelled existing revoke on "
433 "blocknr %llu\n", (unsigned long long)bh->b_blocknr);
434 spin_lock(&journal->j_revoke_lock);
435 list_del(&record->hash);
436 spin_unlock(&journal->j_revoke_lock);
437 kmem_cache_free(revoke_record_cache, record);
438 did_revoke = 1;
439 }
440 }
441
442#ifdef JBD_EXPENSIVE_CHECKING
443 /* There better not be one left behind by now! */
444 record = find_revoke_record(journal, bh->b_blocknr);
445 J_ASSERT_JH(jh, record == NULL);
446#endif
447
448 /* Finally, have we just cleared revoke on an unhashed
449 * buffer_head? If so, we'd better make sure we clear the
450 * revoked status on any hashed alias too, otherwise the revoke
451 * state machine will get very upset later on. */
452 if (need_cancel) {
453 struct buffer_head *bh2;
454 bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size);
455 if (bh2) {
456 if (bh2 != bh)
457 clear_buffer_revoked(bh2);
458 __brelse(bh2);
459 }
460 }
461 return did_revoke;
462}
463
464/* journal_switch_revoke table select j_revoke for next transaction
465 * we do not want to suspend any processing until all revokes are
466 * written -bzzz
467 */
468void journal_switch_revoke_table(journal_t *journal)
469{
470 int i;
471
472 if (journal->j_revoke == journal->j_revoke_table[0])
473 journal->j_revoke = journal->j_revoke_table[1];
474 else
475 journal->j_revoke = journal->j_revoke_table[0];
476
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700477 for (i = 0; i < journal->j_revoke->hash_size; i++)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]);
479}
480
481/*
482 * Write revoke records to the journal for all entries in the current
483 * revoke hash, deleting the entries as we go.
484 *
485 * Called with the journal lock held.
486 */
487
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700488void journal_write_revoke_records(journal_t *journal,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 transaction_t *transaction)
490{
491 struct journal_head *descriptor;
492 struct jbd_revoke_record_s *record;
493 struct jbd_revoke_table_s *revoke;
494 struct list_head *hash_list;
495 int i, offset, count;
496
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700497 descriptor = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 offset = 0;
499 count = 0;
500
501 /* select revoke table for committing transaction */
502 revoke = journal->j_revoke == journal->j_revoke_table[0] ?
503 journal->j_revoke_table[1] : journal->j_revoke_table[0];
504
505 for (i = 0; i < revoke->hash_size; i++) {
506 hash_list = &revoke->hash_table[i];
507
508 while (!list_empty(hash_list)) {
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700509 record = (struct jbd_revoke_record_s *)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 hash_list->next;
511 write_one_revoke_record(journal, transaction,
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700512 &descriptor, &offset,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 record);
514 count++;
515 list_del(&record->hash);
516 kmem_cache_free(revoke_record_cache, record);
517 }
518 }
519 if (descriptor)
520 flush_descriptor(journal, descriptor, offset);
521 jbd_debug(1, "Wrote %d revoke records\n", count);
522}
523
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700524/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 * Write out one revoke record. We need to create a new descriptor
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700526 * block if the old one is full or if we have not already created one.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 */
528
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700529static void write_one_revoke_record(journal_t *journal,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 transaction_t *transaction,
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700531 struct journal_head **descriptorp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 int *offsetp,
533 struct jbd_revoke_record_s *record)
534{
535 struct journal_head *descriptor;
536 int offset;
537 journal_header_t *header;
538
539 /* If we are already aborting, this all becomes a noop. We
540 still need to go round the loop in
541 journal_write_revoke_records in order to free all of the
542 revoke records: only the IO to the journal is omitted. */
543 if (is_journal_aborted(journal))
544 return;
545
546 descriptor = *descriptorp;
547 offset = *offsetp;
548
549 /* Make sure we have a descriptor with space left for the record */
550 if (descriptor) {
551 if (offset == journal->j_blocksize) {
552 flush_descriptor(journal, descriptor, offset);
553 descriptor = NULL;
554 }
555 }
556
557 if (!descriptor) {
558 descriptor = journal_get_descriptor_buffer(journal);
559 if (!descriptor)
560 return;
561 header = (journal_header_t *) &jh2bh(descriptor)->b_data[0];
562 header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
563 header->h_blocktype = cpu_to_be32(JFS_REVOKE_BLOCK);
564 header->h_sequence = cpu_to_be32(transaction->t_tid);
565
566 /* Record it so that we can wait for IO completion later */
567 JBUFFER_TRACE(descriptor, "file as BJ_LogCtl");
568 journal_file_buffer(descriptor, transaction, BJ_LogCtl);
569
570 offset = sizeof(journal_revoke_header_t);
571 *descriptorp = descriptor;
572 }
573
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700574 * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 cpu_to_be32(record->blocknr);
576 offset += 4;
577 *offsetp = offset;
578}
579
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700580/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 * Flush a revoke descriptor out to the journal. If we are aborting,
582 * this is a noop; otherwise we are generating a buffer which needs to
583 * be waited for during commit, so it has to go onto the appropriate
584 * journal buffer list.
585 */
586
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700587static void flush_descriptor(journal_t *journal,
588 struct journal_head *descriptor,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 int offset)
590{
591 journal_revoke_header_t *header;
592 struct buffer_head *bh = jh2bh(descriptor);
593
594 if (is_journal_aborted(journal)) {
595 put_bh(bh);
596 return;
597 }
598
599 header = (journal_revoke_header_t *) jh2bh(descriptor)->b_data;
600 header->r_count = cpu_to_be32(offset);
601 set_buffer_jwrite(bh);
602 BUFFER_TRACE(bh, "write");
603 set_buffer_dirty(bh);
Jan Kara26707692005-09-06 15:19:12 -0700604 ll_rw_block(SWRITE, 1, &bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605}
606#endif
607
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700608/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 * Revoke support for recovery.
610 *
611 * Recovery needs to be able to:
612 *
613 * record all revoke records, including the tid of the latest instance
614 * of each revoke in the journal
615 *
616 * check whether a given block in a given transaction should be replayed
617 * (ie. has not been revoked by a revoke record in that or a subsequent
618 * transaction)
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700619 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 * empty the revoke table after recovery.
621 */
622
623/*
624 * First, setting revoke records. We create a new revoke record for
625 * every block ever revoked in the log as we scan it for recovery, and
626 * we update the existing records if we find multiple revokes for a
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700627 * single block.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 */
629
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700630int journal_set_revoke(journal_t *journal,
631 unsigned long blocknr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 tid_t sequence)
633{
634 struct jbd_revoke_record_s *record;
635
636 record = find_revoke_record(journal, blocknr);
637 if (record) {
638 /* If we have multiple occurrences, only record the
639 * latest sequence number in the hashed record */
640 if (tid_gt(sequence, record->sequence))
641 record->sequence = sequence;
642 return 0;
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700643 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 return insert_revoke_hash(journal, blocknr, sequence);
645}
646
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700647/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 * Test revoke records. For a given block referenced in the log, has
649 * that block been revoked? A revoke record with a given transaction
650 * sequence number revokes all blocks in that transaction and earlier
651 * ones, but later transactions still need replayed.
652 */
653
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700654int journal_test_revoke(journal_t *journal,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 unsigned long blocknr,
656 tid_t sequence)
657{
658 struct jbd_revoke_record_s *record;
659
660 record = find_revoke_record(journal, blocknr);
661 if (!record)
662 return 0;
663 if (tid_gt(sequence, record->sequence))
664 return 0;
665 return 1;
666}
667
668/*
669 * Finally, once recovery is over, we need to clear the revoke table so
670 * that it can be reused by the running filesystem.
671 */
672
673void journal_clear_revoke(journal_t *journal)
674{
675 int i;
676 struct list_head *hash_list;
677 struct jbd_revoke_record_s *record;
678 struct jbd_revoke_table_s *revoke;
679
680 revoke = journal->j_revoke;
681
682 for (i = 0; i < revoke->hash_size; i++) {
683 hash_list = &revoke->hash_table[i];
684 while (!list_empty(hash_list)) {
685 record = (struct jbd_revoke_record_s*) hash_list->next;
686 list_del(&record->hash);
687 kmem_cache_free(revoke_record_cache, record);
688 }
689 }
690}