Branch data 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 : 5031 : static inline int hash(journal_t *journal, unsigned long long block)
132 : : {
133 : 5031 : return hash_64(block, journal->j_revoke->hash_shift);
134 : : }
135 : :
136 : 26 : static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr,
137 : : tid_t seq)
138 : : {
139 : 26 : struct list_head *hash_list;
140 : 26 : struct jbd2_revoke_record_s *record;
141 : 26 : gfp_t gfp_mask = GFP_NOFS;
142 : :
143 : 26 : if (journal_oom_retry)
144 : 26 : gfp_mask |= __GFP_NOFAIL;
145 : 26 : record = kmem_cache_alloc(jbd2_revoke_record_cache, gfp_mask);
146 [ + - ]: 26 : if (!record)
147 : : return -ENOMEM;
148 : :
149 : 26 : record->sequence = seq;
150 : 26 : record->blocknr = blocknr;
151 : 26 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
152 : 26 : spin_lock(&journal->j_revoke_lock);
153 : 26 : list_add(&record->hash, hash_list);
154 : 26 : spin_unlock(&journal->j_revoke_lock);
155 : 26 : return 0;
156 : : }
157 : :
158 : : /* Find a revoke record in the journal's hash table. */
159 : :
160 : 5005 : static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal,
161 : : unsigned long long blocknr)
162 : : {
163 : 5005 : struct list_head *hash_list;
164 : 5005 : struct jbd2_revoke_record_s *record;
165 : :
166 : 5005 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
167 : :
168 : 5005 : spin_lock(&journal->j_revoke_lock);
169 : 5005 : record = (struct jbd2_revoke_record_s *) hash_list->next;
170 [ + + ]: 5057 : while (&(record->hash) != hash_list) {
171 [ - + ]: 52 : if (record->blocknr == blocknr) {
172 : 0 : spin_unlock(&journal->j_revoke_lock);
173 : 0 : return record;
174 : : }
175 : 52 : record = (struct jbd2_revoke_record_s *) record->hash.next;
176 : : }
177 : 5005 : spin_unlock(&journal->j_revoke_lock);
178 : 5005 : 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 : 13 : int __init jbd2_journal_init_revoke_record_cache(void)
194 : : {
195 [ - + ]: 13 : J_ASSERT(!jbd2_revoke_record_cache);
196 : 13 : jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
197 : : SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
198 : :
199 [ - + ]: 13 : 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 : 13 : int __init jbd2_journal_init_revoke_table_cache(void)
207 : : {
208 [ - + ]: 13 : J_ASSERT(!jbd2_revoke_table_cache);
209 : 13 : jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
210 : : SLAB_TEMPORARY);
211 [ - + ]: 13 : 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 : 52 : static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size)
219 : : {
220 : 52 : int shift = 0;
221 : 52 : int tmp = hash_size;
222 : 52 : struct jbd2_revoke_table_s *table;
223 : :
224 : 52 : table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL);
225 [ + - ]: 52 : if (!table)
226 : 0 : goto out;
227 : :
228 [ + + ]: 468 : while((tmp >>= 1UL) != 0UL)
229 : 416 : shift++;
230 : :
231 : 52 : table->hash_size = hash_size;
232 : 52 : table->hash_shift = shift;
233 : 104 : table->hash_table =
234 : 52 : kmalloc_array(hash_size, sizeof(struct list_head), GFP_KERNEL);
235 [ + - ]: 52 : 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 [ + + ]: 13364 : for (tmp = 0; tmp < hash_size; tmp++)
242 : 13312 : INIT_LIST_HEAD(&table->hash_table[tmp]);
243 : :
244 : 52 : out:
245 : 52 : 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 : 26 : int jbd2_journal_init_revoke(journal_t *journal, int hash_size)
264 : : {
265 [ - + ]: 26 : J_ASSERT(journal->j_revoke_table[0] == NULL);
266 [ + - - + ]: 52 : J_ASSERT(is_power_of_2(hash_size));
267 : :
268 : 26 : journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size);
269 [ - + ]: 26 : if (!journal->j_revoke_table[0])
270 : 0 : goto fail0;
271 : :
272 : 26 : journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size);
273 [ - + ]: 26 : if (!journal->j_revoke_table[1])
274 : 0 : goto fail1;
275 : :
276 : 26 : journal->j_revoke = journal->j_revoke_table[1];
277 : :
278 : 26 : spin_lock_init(&journal->j_revoke_lock);
279 : :
280 : 26 : 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 : 26 : int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr,
327 : : struct buffer_head *bh_in)
328 : : {
329 : 26 : struct buffer_head *bh = NULL;
330 : 26 : journal_t *journal;
331 : 26 : struct block_device *bdev;
332 : 26 : int err;
333 : :
334 : 26 : might_sleep();
335 : 26 : if (bh_in)
336 : 26 : BUFFER_TRACE(bh_in, "enter");
337 : :
338 : 26 : journal = handle->h_transaction->t_journal;
339 [ - + ]: 26 : 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 : 26 : bdev = journal->j_fs_dev;
345 : 26 : bh = bh_in;
346 : :
347 [ - + ]: 26 : if (!bh) {
348 : 0 : bh = __find_get_block(bdev, blocknr, journal->j_blocksize);
349 : 0 : if (bh)
350 : 26 : BUFFER_TRACE(bh, "found on hash");
351 : : }
352 : : #ifdef JBD2_EXPENSIVE_CHECKING
353 : : else {
354 : : struct buffer_head *bh2;
355 : :
356 : : /* If there is a different buffer_head lying around in
357 : : * memory anywhere... */
358 : : bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize);
359 : : if (bh2) {
360 : : /* ... and it has RevokeValid status... */
361 : : 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 : : J_ASSERT_BH(bh2, buffer_revoked(bh2));
369 : : put_bh(bh2);
370 : : }
371 : : }
372 : : #endif
373 : :
374 [ - + - + ]: 26 : 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 [ + - ]: 26 : if (bh) {
383 [ - + - + ]: 26 : 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 : 26 : set_buffer_revoked(bh);
390 : 26 : set_buffer_revokevalid(bh);
391 [ + - ]: 26 : if (bh_in) {
392 : 26 : BUFFER_TRACE(bh_in, "call jbd2_journal_forget");
393 : 26 : jbd2_journal_forget(handle, bh_in);
394 : : } else {
395 : 0 : BUFFER_TRACE(bh, "call brelse");
396 : 0 : __brelse(bh);
397 : : }
398 : : }
399 : 26 : handle->h_revoke_credits--;
400 : :
401 : 26 : jbd_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in);
402 : 26 : err = insert_revoke_hash(journal, blocknr,
403 : 26 : handle->h_transaction->t_tid);
404 : 26 : BUFFER_TRACE(bh_in, "exit");
405 : 26 : 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 : 6035 : int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
424 : : {
425 : 6035 : struct jbd2_revoke_record_s *record;
426 : 6035 : journal_t *journal = handle->h_transaction->t_journal;
427 : 6035 : int need_cancel;
428 : 6035 : int did_revoke = 0; /* akpm: debug */
429 : 6035 : struct buffer_head *bh = jh2bh(jh);
430 : :
431 : 6035 : jbd_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 [ + + ]: 6035 : if (test_set_buffer_revokevalid(bh)) {
438 : 1030 : need_cancel = test_clear_buffer_revoked(bh);
439 : : } else {
440 : 5005 : need_cancel = 1;
441 : 5005 : clear_buffer_revoked(bh);
442 : : }
443 : :
444 [ - + ]: 6035 : if (need_cancel) {
445 : 5005 : record = find_revoke_record(journal, bh->b_blocknr);
446 [ - + ]: 5005 : if (record) {
447 : : jbd_debug(4, "cancelled existing revoke on "
448 : 0 : "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 : : record = find_revoke_record(journal, bh->b_blocknr);
460 : : 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 [ + + ]: 6035 : if (need_cancel) {
468 : 5005 : struct buffer_head *bh2;
469 : 5005 : bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size);
470 [ + - ]: 5005 : if (bh2) {
471 [ - + ]: 5005 : if (bh2 != bh)
472 : 0 : clear_buffer_revoked(bh2);
473 : 5005 : __brelse(bh2);
474 : : }
475 : : }
476 : 6035 : 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 : 93 : void jbd2_clear_buffer_revoked_flags(journal_t *journal)
485 : : {
486 : 93 : struct jbd2_revoke_table_s *revoke = journal->j_revoke;
487 : 93 : int i = 0;
488 : :
489 [ + + ]: 23901 : for (i = 0; i < revoke->hash_size; i++) {
490 : 23808 : struct list_head *hash_list;
491 : 23808 : struct list_head *list_entry;
492 : 23808 : hash_list = &revoke->hash_table[i];
493 : :
494 [ - + ]: 23808 : 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 : 93 : }
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 : 93 : void jbd2_journal_switch_revoke_table(journal_t *journal)
514 : : {
515 : 93 : int i;
516 : :
517 [ + + ]: 93 : if (journal->j_revoke == journal->j_revoke_table[0])
518 : 41 : journal->j_revoke = journal->j_revoke_table[1];
519 : : else
520 : 52 : journal->j_revoke = journal->j_revoke_table[0];
521 : :
522 [ + + ]: 23901 : for (i = 0; i < journal->j_revoke->hash_size; i++)
523 : 23808 : INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]);
524 : 93 : }
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 : 93 : void jbd2_journal_write_revoke_records(transaction_t *transaction,
531 : : struct list_head *log_bufs)
532 : : {
533 : 93 : journal_t *journal = transaction->t_journal;
534 : 93 : struct buffer_head *descriptor;
535 : 93 : struct jbd2_revoke_record_s *record;
536 : 93 : struct jbd2_revoke_table_s *revoke;
537 : 93 : struct list_head *hash_list;
538 : 93 : int i, offset, count;
539 : :
540 : 93 : descriptor = NULL;
541 : 93 : offset = 0;
542 : 93 : count = 0;
543 : :
544 : : /* select revoke table for committing transaction */
545 : 93 : revoke = journal->j_revoke == journal->j_revoke_table[0] ?
546 [ + + ]: 93 : journal->j_revoke_table[1] : journal->j_revoke_table[0];
547 : :
548 [ + + ]: 23901 : for (i = 0; i < revoke->hash_size; i++) {
549 : 23808 : hash_list = &revoke->hash_table[i];
550 : :
551 [ - + ]: 23808 : 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 [ - + ]: 93 : if (descriptor)
562 : 0 : flush_descriptor(journal, descriptor, offset);
563 : 93 : jbd_debug(1, "Wrote %d revoke records\n", count);
564 : 93 : }
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 : : 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 : : journal_t *journal = transaction->t_journal;
578 : : int csum_size = 0;
579 : : struct buffer_head *descriptor;
580 : : 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 : : if (is_journal_aborted(journal))
587 : : return;
588 : :
589 : : descriptor = *descriptorp;
590 : : offset = *offsetp;
591 : :
592 : : /* Do we need to leave space at the end for a checksum? */
593 : : if (jbd2_journal_has_csum_v2or3(journal))
594 : : csum_size = sizeof(struct jbd2_journal_block_tail);
595 : :
596 : : if (jbd2_has_feature_64bit(journal))
597 : : sz = 8;
598 : : else
599 : : sz = 4;
600 : :
601 : : /* Make sure we have a descriptor with space left for the record */
602 : : if (descriptor) {
603 : : if (offset + sz > journal->j_blocksize - csum_size) {
604 : : flush_descriptor(journal, descriptor, offset);
605 : : descriptor = NULL;
606 : : }
607 : : }
608 : :
609 : : if (!descriptor) {
610 : : descriptor = jbd2_journal_get_descriptor_buffer(transaction,
611 : : JBD2_REVOKE_BLOCK);
612 : : if (!descriptor)
613 : : return;
614 : :
615 : : /* Record it so that we can wait for IO completion later */
616 : : BUFFER_TRACE(descriptor, "file in log_bufs");
617 : : jbd2_file_log_bh(log_bufs, descriptor);
618 : :
619 : : offset = sizeof(jbd2_journal_revoke_header_t);
620 : : *descriptorp = descriptor;
621 : : }
622 : :
623 : : if (jbd2_has_feature_64bit(journal))
624 : : * ((__be64 *)(&descriptor->b_data[offset])) =
625 : : cpu_to_be64(record->blocknr);
626 : : else
627 : : * ((__be32 *)(&descriptor->b_data[offset])) =
628 : : cpu_to_be32(record->blocknr);
629 : : offset += sz;
630 : :
631 : : *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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