Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0+
2 : /*
3 : * linux/fs/jbd2/revoke.c
4 : *
5 : * Written by Stephen C. Tweedie <sct@redhat.com>, 2000
6 : *
7 : * Copyright 2000 Red Hat corp --- All Rights Reserved
8 : *
9 : * Journal revoke routines for the generic filesystem journaling code;
10 : * part of the ext2fs journaling system.
11 : *
12 : * Revoke is the mechanism used to prevent old log records for deleted
13 : * metadata from being replayed on top of newer data using the same
14 : * blocks. The revoke mechanism is used in two separate places:
15 : *
16 : * + Commit: during commit we write the entire list of the current
17 : * transaction's revoked blocks to the journal
18 : *
19 : * + Recovery: during recovery we record the transaction ID of all
20 : * revoked blocks. If there are multiple revoke records in the log
21 : * for a single block, only the last one counts, and if there is a log
22 : * entry for a block beyond the last revoke, then that log entry still
23 : * gets replayed.
24 : *
25 : * We can get interactions between revokes and new log data within a
26 : * single transaction:
27 : *
28 : * Block is revoked and then journaled:
29 : * The desired end result is the journaling of the new block, so we
30 : * cancel the revoke before the transaction commits.
31 : *
32 : * Block is journaled and then revoked:
33 : * The revoke must take precedence over the write of the block, so we
34 : * need either to cancel the journal entry or to write the revoke
35 : * later in the log than the log block. In this case, we choose the
36 : * latter: journaling a block cancels any revoke record for that block
37 : * in the current transaction, so any revoke for that block in the
38 : * transaction must have happened after the block was journaled and so
39 : * the revoke must take precedence.
40 : *
41 : * Block is revoked and then written as data:
42 : * The data write is allowed to succeed, but the revoke is _not_
43 : * cancelled. We still need to prevent old log records from
44 : * overwriting the new data. We don't even need to clear the revoke
45 : * bit here.
46 : *
47 : * We cache revoke status of a buffer in the current transaction in b_states
48 : * bits. As the name says, revokevalid flag indicates that the cached revoke
49 : * status of a buffer is valid and we can rely on the cached status.
50 : *
51 : * Revoke information on buffers is a tri-state value:
52 : *
53 : * RevokeValid clear: no cached revoke status, need to look it up
54 : * RevokeValid set, Revoked clear:
55 : * buffer has not been revoked, and cancel_revoke
56 : * need do nothing.
57 : * RevokeValid set, Revoked set:
58 : * buffer has been revoked.
59 : *
60 : * Locking rules:
61 : * We keep two hash tables of revoke records. One hashtable belongs to the
62 : * running transaction (is pointed to by journal->j_revoke), the other one
63 : * belongs to the committing transaction. Accesses to the second hash table
64 : * happen only from the kjournald and no other thread touches this table. Also
65 : * journal_switch_revoke_table() which switches which hashtable belongs to the
66 : * running and which to the committing transaction is called only from
67 : * kjournald. Therefore we need no locks when accessing the hashtable belonging
68 : * to the committing transaction.
69 : *
70 : * All users operating on the hash table belonging to the running transaction
71 : * have a handle to the transaction. Therefore they are safe from kjournald
72 : * switching hash tables under them. For operations on the lists of entries in
73 : * the hash table j_revoke_lock is used.
74 : *
75 : * Finally, also replay code uses the hash tables but at this moment no one else
76 : * can touch them (filesystem isn't mounted yet) and hence no locking is
77 : * needed.
78 : */
79 :
80 : #ifndef __KERNEL__
81 : #include "jfs_user.h"
82 : #else
83 : #include <linux/time.h>
84 : #include <linux/fs.h>
85 : #include <linux/jbd2.h>
86 : #include <linux/errno.h>
87 : #include <linux/slab.h>
88 : #include <linux/list.h>
89 : #include <linux/init.h>
90 : #include <linux/bio.h>
91 : #include <linux/log2.h>
92 : #include <linux/hash.h>
93 : #endif
94 :
95 : static struct kmem_cache *jbd2_revoke_record_cache;
96 : static struct kmem_cache *jbd2_revoke_table_cache;
97 :
98 : /* Each revoke record represents one single revoked block. During
99 : journal replay, this involves recording the transaction ID of the
100 : last transaction to revoke this block. */
101 :
102 : struct jbd2_revoke_record_s
103 : {
104 : struct list_head hash;
105 : tid_t sequence; /* Used for recovery only */
106 : unsigned long long blocknr;
107 : };
108 :
109 :
110 : /* The revoke table is just a simple hash table of revoke records. */
111 : struct jbd2_revoke_table_s
112 : {
113 : /* It is conceivable that we might want a larger hash table
114 : * for recovery. Must be a power of two. */
115 : int hash_size;
116 : int hash_shift;
117 : struct list_head *hash_table;
118 : };
119 :
120 :
121 : #ifdef __KERNEL__
122 : static void write_one_revoke_record(transaction_t *,
123 : struct list_head *,
124 : struct buffer_head **, int *,
125 : struct jbd2_revoke_record_s *);
126 : static void flush_descriptor(journal_t *, struct buffer_head *, int);
127 : #endif
128 :
129 : /* Utility functions to maintain the revoke table */
130 :
131 : static inline int hash(journal_t *journal, unsigned long long block)
132 : {
133 0 : return hash_64(block, journal->j_revoke->hash_shift);
134 : }
135 :
136 0 : static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr,
137 : tid_t seq)
138 : {
139 0 : struct list_head *hash_list;
140 0 : struct jbd2_revoke_record_s *record;
141 0 : gfp_t gfp_mask = GFP_NOFS;
142 :
143 0 : if (journal_oom_retry)
144 0 : gfp_mask |= __GFP_NOFAIL;
145 0 : record = kmem_cache_alloc(jbd2_revoke_record_cache, gfp_mask);
146 0 : if (!record)
147 : return -ENOMEM;
148 :
149 0 : record->sequence = seq;
150 0 : record->blocknr = blocknr;
151 0 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
152 0 : spin_lock(&journal->j_revoke_lock);
153 0 : list_add(&record->hash, hash_list);
154 0 : spin_unlock(&journal->j_revoke_lock);
155 0 : return 0;
156 : }
157 :
158 : /* Find a revoke record in the journal's hash table. */
159 :
160 0 : static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal,
161 : unsigned long long blocknr)
162 : {
163 0 : struct list_head *hash_list;
164 0 : struct jbd2_revoke_record_s *record;
165 :
166 0 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
167 :
168 0 : spin_lock(&journal->j_revoke_lock);
169 0 : record = (struct jbd2_revoke_record_s *) hash_list->next;
170 0 : while (&(record->hash) != hash_list) {
171 0 : if (record->blocknr == blocknr) {
172 0 : spin_unlock(&journal->j_revoke_lock);
173 0 : return record;
174 : }
175 0 : record = (struct jbd2_revoke_record_s *) record->hash.next;
176 : }
177 0 : spin_unlock(&journal->j_revoke_lock);
178 0 : return NULL;
179 : }
180 :
181 0 : void jbd2_journal_destroy_revoke_record_cache(void)
182 : {
183 0 : kmem_cache_destroy(jbd2_revoke_record_cache);
184 0 : jbd2_revoke_record_cache = NULL;
185 0 : }
186 :
187 0 : void jbd2_journal_destroy_revoke_table_cache(void)
188 : {
189 0 : kmem_cache_destroy(jbd2_revoke_table_cache);
190 0 : jbd2_revoke_table_cache = NULL;
191 0 : }
192 :
193 2 : int __init jbd2_journal_init_revoke_record_cache(void)
194 : {
195 2 : J_ASSERT(!jbd2_revoke_record_cache);
196 2 : jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
197 : SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
198 :
199 2 : if (!jbd2_revoke_record_cache) {
200 0 : pr_emerg("JBD2: failed to create revoke_record cache\n");
201 0 : return -ENOMEM;
202 : }
203 : return 0;
204 : }
205 :
206 2 : int __init jbd2_journal_init_revoke_table_cache(void)
207 : {
208 2 : J_ASSERT(!jbd2_revoke_table_cache);
209 2 : jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
210 : SLAB_TEMPORARY);
211 2 : if (!jbd2_revoke_table_cache) {
212 0 : pr_emerg("JBD2: failed to create revoke_table cache\n");
213 0 : return -ENOMEM;
214 : }
215 : return 0;
216 : }
217 :
218 0 : static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size)
219 : {
220 0 : int shift = 0;
221 0 : int tmp = hash_size;
222 0 : struct jbd2_revoke_table_s *table;
223 :
224 0 : table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL);
225 0 : if (!table)
226 0 : goto out;
227 :
228 0 : while((tmp >>= 1UL) != 0UL)
229 0 : shift++;
230 :
231 0 : table->hash_size = hash_size;
232 0 : table->hash_shift = shift;
233 0 : table->hash_table =
234 0 : kmalloc_array(hash_size, sizeof(struct list_head), GFP_KERNEL);
235 0 : if (!table->hash_table) {
236 0 : kmem_cache_free(jbd2_revoke_table_cache, table);
237 0 : table = NULL;
238 0 : goto out;
239 : }
240 :
241 0 : for (tmp = 0; tmp < hash_size; tmp++)
242 0 : INIT_LIST_HEAD(&table->hash_table[tmp]);
243 :
244 0 : out:
245 0 : return table;
246 : }
247 :
248 0 : static void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table)
249 : {
250 0 : int i;
251 0 : struct list_head *hash_list;
252 :
253 0 : for (i = 0; i < table->hash_size; i++) {
254 0 : hash_list = &table->hash_table[i];
255 0 : J_ASSERT(list_empty(hash_list));
256 : }
257 :
258 0 : kfree(table->hash_table);
259 0 : kmem_cache_free(jbd2_revoke_table_cache, table);
260 0 : }
261 :
262 : /* Initialise the revoke table for a given journal to a given size. */
263 0 : int jbd2_journal_init_revoke(journal_t *journal, int hash_size)
264 : {
265 0 : J_ASSERT(journal->j_revoke_table[0] == NULL);
266 0 : J_ASSERT(is_power_of_2(hash_size));
267 :
268 0 : journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size);
269 0 : if (!journal->j_revoke_table[0])
270 0 : goto fail0;
271 :
272 0 : journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size);
273 0 : if (!journal->j_revoke_table[1])
274 0 : goto fail1;
275 :
276 0 : journal->j_revoke = journal->j_revoke_table[1];
277 :
278 0 : spin_lock_init(&journal->j_revoke_lock);
279 :
280 0 : return 0;
281 :
282 : fail1:
283 0 : jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
284 0 : journal->j_revoke_table[0] = NULL;
285 : fail0:
286 : return -ENOMEM;
287 : }
288 :
289 : /* Destroy a journal's revoke table. The table must already be empty! */
290 0 : void jbd2_journal_destroy_revoke(journal_t *journal)
291 : {
292 0 : journal->j_revoke = NULL;
293 0 : if (journal->j_revoke_table[0])
294 0 : jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
295 0 : if (journal->j_revoke_table[1])
296 0 : jbd2_journal_destroy_revoke_table(journal->j_revoke_table[1]);
297 0 : }
298 :
299 :
300 : #ifdef __KERNEL__
301 :
302 : /*
303 : * jbd2_journal_revoke: revoke a given buffer_head from the journal. This
304 : * prevents the block from being replayed during recovery if we take a
305 : * crash after this current transaction commits. Any subsequent
306 : * metadata writes of the buffer in this transaction cancel the
307 : * revoke.
308 : *
309 : * Note that this call may block --- it is up to the caller to make
310 : * sure that there are no further calls to journal_write_metadata
311 : * before the revoke is complete. In ext3, this implies calling the
312 : * revoke before clearing the block bitmap when we are deleting
313 : * metadata.
314 : *
315 : * Revoke performs a jbd2_journal_forget on any buffer_head passed in as a
316 : * parameter, but does _not_ forget the buffer_head if the bh was only
317 : * found implicitly.
318 : *
319 : * bh_in may not be a journalled buffer - it may have come off
320 : * the hash tables without an attached journal_head.
321 : *
322 : * If bh_in is non-zero, jbd2_journal_revoke() will decrement its b_count
323 : * by one.
324 : */
325 :
326 0 : int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr,
327 : struct buffer_head *bh_in)
328 : {
329 0 : struct buffer_head *bh = NULL;
330 0 : journal_t *journal;
331 0 : struct block_device *bdev;
332 0 : int err;
333 :
334 0 : might_sleep();
335 0 : if (bh_in)
336 0 : BUFFER_TRACE(bh_in, "enter");
337 :
338 0 : journal = handle->h_transaction->t_journal;
339 0 : if (!jbd2_journal_set_features(journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)){
340 0 : J_ASSERT (!"Cannot set revoke feature!");
341 : return -EINVAL;
342 : }
343 :
344 0 : bdev = journal->j_fs_dev;
345 0 : bh = bh_in;
346 :
347 0 : if (!bh) {
348 0 : bh = __find_get_block(bdev, blocknr, journal->j_blocksize);
349 0 : if (bh)
350 0 : BUFFER_TRACE(bh, "found on hash");
351 : }
352 : #ifdef JBD2_EXPENSIVE_CHECKING
353 : else {
354 0 : struct buffer_head *bh2;
355 :
356 : /* If there is a different buffer_head lying around in
357 : * memory anywhere... */
358 0 : bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize);
359 0 : if (bh2) {
360 : /* ... and it has RevokeValid status... */
361 0 : if (bh2 != bh && buffer_revokevalid(bh2))
362 : /* ...then it better be revoked too,
363 : * since it's illegal to create a revoke
364 : * record against a buffer_head which is
365 : * not marked revoked --- that would
366 : * risk missing a subsequent revoke
367 : * cancel. */
368 0 : J_ASSERT_BH(bh2, buffer_revoked(bh2));
369 0 : put_bh(bh2);
370 : }
371 : }
372 : #endif
373 :
374 0 : if (WARN_ON_ONCE(handle->h_revoke_credits <= 0)) {
375 0 : if (!bh_in)
376 0 : brelse(bh);
377 0 : return -EIO;
378 : }
379 : /* We really ought not ever to revoke twice in a row without
380 : first having the revoke cancelled: it's illegal to free a
381 : block twice without allocating it in between! */
382 0 : if (bh) {
383 0 : if (!J_EXPECT_BH(bh, !buffer_revoked(bh),
384 : "inconsistent data on disk")) {
385 0 : if (!bh_in)
386 0 : brelse(bh);
387 0 : return -EIO;
388 : }
389 0 : set_buffer_revoked(bh);
390 0 : set_buffer_revokevalid(bh);
391 0 : if (bh_in) {
392 0 : BUFFER_TRACE(bh_in, "call jbd2_journal_forget");
393 0 : jbd2_journal_forget(handle, bh_in);
394 : } else {
395 0 : BUFFER_TRACE(bh, "call brelse");
396 0 : __brelse(bh);
397 : }
398 : }
399 0 : handle->h_revoke_credits--;
400 :
401 0 : jbd2_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in);
402 0 : err = insert_revoke_hash(journal, blocknr,
403 0 : handle->h_transaction->t_tid);
404 0 : BUFFER_TRACE(bh_in, "exit");
405 0 : return err;
406 : }
407 :
408 : /*
409 : * Cancel an outstanding revoke. For use only internally by the
410 : * journaling code (called from jbd2_journal_get_write_access).
411 : *
412 : * We trust buffer_revoked() on the buffer if the buffer is already
413 : * being journaled: if there is no revoke pending on the buffer, then we
414 : * don't do anything here.
415 : *
416 : * This would break if it were possible for a buffer to be revoked and
417 : * discarded, and then reallocated within the same transaction. In such
418 : * a case we would have lost the revoked bit, but when we arrived here
419 : * the second time we would still have a pending revoke to cancel. So,
420 : * do not trust the Revoked bit on buffers unless RevokeValid is also
421 : * set.
422 : */
423 0 : int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
424 : {
425 0 : struct jbd2_revoke_record_s *record;
426 0 : journal_t *journal = handle->h_transaction->t_journal;
427 0 : int need_cancel;
428 0 : int did_revoke = 0; /* akpm: debug */
429 0 : struct buffer_head *bh = jh2bh(jh);
430 :
431 0 : jbd2_debug(4, "journal_head %p, cancelling revoke\n", jh);
432 :
433 : /* Is the existing Revoke bit valid? If so, we trust it, and
434 : * only perform the full cancel if the revoke bit is set. If
435 : * not, we can't trust the revoke bit, and we need to do the
436 : * full search for a revoke record. */
437 0 : if (test_set_buffer_revokevalid(bh)) {
438 0 : need_cancel = test_clear_buffer_revoked(bh);
439 : } else {
440 0 : need_cancel = 1;
441 0 : clear_buffer_revoked(bh);
442 : }
443 :
444 0 : if (need_cancel) {
445 0 : record = find_revoke_record(journal, bh->b_blocknr);
446 0 : if (record) {
447 0 : jbd2_debug(4, "cancelled existing revoke on "
448 : "blocknr %llu\n", (unsigned long long)bh->b_blocknr);
449 0 : spin_lock(&journal->j_revoke_lock);
450 0 : list_del(&record->hash);
451 0 : spin_unlock(&journal->j_revoke_lock);
452 0 : kmem_cache_free(jbd2_revoke_record_cache, record);
453 0 : did_revoke = 1;
454 : }
455 : }
456 :
457 : #ifdef JBD2_EXPENSIVE_CHECKING
458 : /* There better not be one left behind by now! */
459 0 : record = find_revoke_record(journal, bh->b_blocknr);
460 0 : J_ASSERT_JH(jh, record == NULL);
461 : #endif
462 :
463 : /* Finally, have we just cleared revoke on an unhashed
464 : * buffer_head? If so, we'd better make sure we clear the
465 : * revoked status on any hashed alias too, otherwise the revoke
466 : * state machine will get very upset later on. */
467 0 : if (need_cancel) {
468 0 : struct buffer_head *bh2;
469 0 : bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size);
470 0 : if (bh2) {
471 0 : if (bh2 != bh)
472 0 : clear_buffer_revoked(bh2);
473 0 : __brelse(bh2);
474 : }
475 : }
476 0 : return did_revoke;
477 : }
478 :
479 : /*
480 : * journal_clear_revoked_flag clears revoked flag of buffers in
481 : * revoke table to reflect there is no revoked buffers in the next
482 : * transaction which is going to be started.
483 : */
484 0 : void jbd2_clear_buffer_revoked_flags(journal_t *journal)
485 : {
486 0 : struct jbd2_revoke_table_s *revoke = journal->j_revoke;
487 0 : int i = 0;
488 :
489 0 : for (i = 0; i < revoke->hash_size; i++) {
490 0 : struct list_head *hash_list;
491 0 : struct list_head *list_entry;
492 0 : hash_list = &revoke->hash_table[i];
493 :
494 0 : list_for_each(list_entry, hash_list) {
495 0 : struct jbd2_revoke_record_s *record;
496 0 : struct buffer_head *bh;
497 0 : record = (struct jbd2_revoke_record_s *)list_entry;
498 0 : bh = __find_get_block(journal->j_fs_dev,
499 : record->blocknr,
500 0 : journal->j_blocksize);
501 0 : if (bh) {
502 0 : clear_buffer_revoked(bh);
503 0 : __brelse(bh);
504 : }
505 : }
506 : }
507 0 : }
508 :
509 : /* journal_switch_revoke table select j_revoke for next transaction
510 : * we do not want to suspend any processing until all revokes are
511 : * written -bzzz
512 : */
513 0 : void jbd2_journal_switch_revoke_table(journal_t *journal)
514 : {
515 0 : int i;
516 :
517 0 : if (journal->j_revoke == journal->j_revoke_table[0])
518 0 : journal->j_revoke = journal->j_revoke_table[1];
519 : else
520 0 : journal->j_revoke = journal->j_revoke_table[0];
521 :
522 0 : for (i = 0; i < journal->j_revoke->hash_size; i++)
523 0 : INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]);
524 0 : }
525 :
526 : /*
527 : * Write revoke records to the journal for all entries in the current
528 : * revoke hash, deleting the entries as we go.
529 : */
530 0 : void jbd2_journal_write_revoke_records(transaction_t *transaction,
531 : struct list_head *log_bufs)
532 : {
533 0 : journal_t *journal = transaction->t_journal;
534 0 : struct buffer_head *descriptor;
535 0 : struct jbd2_revoke_record_s *record;
536 0 : struct jbd2_revoke_table_s *revoke;
537 0 : struct list_head *hash_list;
538 0 : int i, offset, count;
539 :
540 0 : descriptor = NULL;
541 0 : offset = 0;
542 0 : count = 0;
543 :
544 : /* select revoke table for committing transaction */
545 0 : revoke = journal->j_revoke == journal->j_revoke_table[0] ?
546 0 : journal->j_revoke_table[1] : journal->j_revoke_table[0];
547 :
548 0 : for (i = 0; i < revoke->hash_size; i++) {
549 0 : hash_list = &revoke->hash_table[i];
550 :
551 0 : while (!list_empty(hash_list)) {
552 0 : record = (struct jbd2_revoke_record_s *)
553 : hash_list->next;
554 0 : write_one_revoke_record(transaction, log_bufs,
555 : &descriptor, &offset, record);
556 0 : count++;
557 0 : list_del(&record->hash);
558 0 : kmem_cache_free(jbd2_revoke_record_cache, record);
559 : }
560 : }
561 0 : if (descriptor)
562 0 : flush_descriptor(journal, descriptor, offset);
563 0 : jbd2_debug(1, "Wrote %d revoke records\n", count);
564 0 : }
565 :
566 : /*
567 : * Write out one revoke record. We need to create a new descriptor
568 : * block if the old one is full or if we have not already created one.
569 : */
570 :
571 0 : static void write_one_revoke_record(transaction_t *transaction,
572 : struct list_head *log_bufs,
573 : struct buffer_head **descriptorp,
574 : int *offsetp,
575 : struct jbd2_revoke_record_s *record)
576 : {
577 0 : journal_t *journal = transaction->t_journal;
578 0 : int csum_size = 0;
579 0 : struct buffer_head *descriptor;
580 0 : int sz, offset;
581 :
582 : /* If we are already aborting, this all becomes a noop. We
583 : still need to go round the loop in
584 : jbd2_journal_write_revoke_records in order to free all of the
585 : revoke records: only the IO to the journal is omitted. */
586 0 : if (is_journal_aborted(journal))
587 : return;
588 :
589 0 : descriptor = *descriptorp;
590 0 : offset = *offsetp;
591 :
592 : /* Do we need to leave space at the end for a checksum? */
593 0 : if (jbd2_journal_has_csum_v2or3(journal))
594 0 : csum_size = sizeof(struct jbd2_journal_block_tail);
595 :
596 0 : if (jbd2_has_feature_64bit(journal))
597 : sz = 8;
598 : else
599 0 : sz = 4;
600 :
601 : /* Make sure we have a descriptor with space left for the record */
602 0 : if (descriptor) {
603 0 : if (offset + sz > journal->j_blocksize - csum_size) {
604 0 : flush_descriptor(journal, descriptor, offset);
605 0 : descriptor = NULL;
606 : }
607 : }
608 :
609 0 : if (!descriptor) {
610 0 : descriptor = jbd2_journal_get_descriptor_buffer(transaction,
611 : JBD2_REVOKE_BLOCK);
612 0 : if (!descriptor)
613 : return;
614 :
615 : /* Record it so that we can wait for IO completion later */
616 0 : BUFFER_TRACE(descriptor, "file in log_bufs");
617 0 : jbd2_file_log_bh(log_bufs, descriptor);
618 :
619 0 : offset = sizeof(jbd2_journal_revoke_header_t);
620 0 : *descriptorp = descriptor;
621 : }
622 :
623 0 : if (jbd2_has_feature_64bit(journal))
624 0 : * ((__be64 *)(&descriptor->b_data[offset])) =
625 0 : cpu_to_be64(record->blocknr);
626 : else
627 0 : * ((__be32 *)(&descriptor->b_data[offset])) =
628 0 : cpu_to_be32(record->blocknr);
629 0 : offset += sz;
630 :
631 0 : *offsetp = offset;
632 : }
633 :
634 : /*
635 : * Flush a revoke descriptor out to the journal. If we are aborting,
636 : * this is a noop; otherwise we are generating a buffer which needs to
637 : * be waited for during commit, so it has to go onto the appropriate
638 : * journal buffer list.
639 : */
640 :
641 0 : static void flush_descriptor(journal_t *journal,
642 : struct buffer_head *descriptor,
643 : int offset)
644 : {
645 0 : jbd2_journal_revoke_header_t *header;
646 :
647 0 : if (is_journal_aborted(journal))
648 : return;
649 :
650 0 : header = (jbd2_journal_revoke_header_t *)descriptor->b_data;
651 0 : header->r_count = cpu_to_be32(offset);
652 0 : jbd2_descriptor_block_csum_set(journal, descriptor);
653 :
654 0 : set_buffer_jwrite(descriptor);
655 0 : BUFFER_TRACE(descriptor, "write");
656 0 : set_buffer_dirty(descriptor);
657 0 : write_dirty_buffer(descriptor, REQ_SYNC);
658 : }
659 : #endif
660 :
661 : /*
662 : * Revoke support for recovery.
663 : *
664 : * Recovery needs to be able to:
665 : *
666 : * record all revoke records, including the tid of the latest instance
667 : * of each revoke in the journal
668 : *
669 : * check whether a given block in a given transaction should be replayed
670 : * (ie. has not been revoked by a revoke record in that or a subsequent
671 : * transaction)
672 : *
673 : * empty the revoke table after recovery.
674 : */
675 :
676 : /*
677 : * First, setting revoke records. We create a new revoke record for
678 : * every block ever revoked in the log as we scan it for recovery, and
679 : * we update the existing records if we find multiple revokes for a
680 : * single block.
681 : */
682 :
683 0 : int jbd2_journal_set_revoke(journal_t *journal,
684 : unsigned long long blocknr,
685 : tid_t sequence)
686 : {
687 0 : struct jbd2_revoke_record_s *record;
688 :
689 0 : record = find_revoke_record(journal, blocknr);
690 0 : if (record) {
691 : /* If we have multiple occurrences, only record the
692 : * latest sequence number in the hashed record */
693 0 : if (tid_gt(sequence, record->sequence))
694 0 : record->sequence = sequence;
695 0 : return 0;
696 : }
697 0 : return insert_revoke_hash(journal, blocknr, sequence);
698 : }
699 :
700 : /*
701 : * Test revoke records. For a given block referenced in the log, has
702 : * that block been revoked? A revoke record with a given transaction
703 : * sequence number revokes all blocks in that transaction and earlier
704 : * ones, but later transactions still need replayed.
705 : */
706 :
707 0 : int jbd2_journal_test_revoke(journal_t *journal,
708 : unsigned long long blocknr,
709 : tid_t sequence)
710 : {
711 0 : struct jbd2_revoke_record_s *record;
712 :
713 0 : record = find_revoke_record(journal, blocknr);
714 0 : if (!record)
715 : return 0;
716 0 : if (tid_gt(sequence, record->sequence))
717 0 : return 0;
718 : return 1;
719 : }
720 :
721 : /*
722 : * Finally, once recovery is over, we need to clear the revoke table so
723 : * that it can be reused by the running filesystem.
724 : */
725 :
726 0 : void jbd2_journal_clear_revoke(journal_t *journal)
727 : {
728 0 : int i;
729 0 : struct list_head *hash_list;
730 0 : struct jbd2_revoke_record_s *record;
731 0 : struct jbd2_revoke_table_s *revoke;
732 :
733 0 : revoke = journal->j_revoke;
734 :
735 0 : for (i = 0; i < revoke->hash_size; i++) {
736 0 : hash_list = &revoke->hash_table[i];
737 0 : while (!list_empty(hash_list)) {
738 0 : record = (struct jbd2_revoke_record_s*) hash_list->next;
739 0 : list_del(&record->hash);
740 0 : kmem_cache_free(jbd2_revoke_record_cache, record);
741 : }
742 : }
743 0 : }
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