Branch data Line data Source code
1 : : /*
2 : : * linux/fs/jbd2/revoke.c
3 : : *
4 : : * Written by Stephen C. Tweedie <sct@redhat.com>, 2000
5 : : *
6 : : * Copyright 2000 Red Hat corp --- All Rights Reserved
7 : : *
8 : : * This file is part of the Linux kernel and is made available under
9 : : * the terms of the GNU General Public License, version 2, or at your
10 : : * option, any later version, incorporated herein by reference.
11 : : *
12 : : * Journal revoke routines for the generic filesystem journaling code;
13 : : * part of the ext2fs journaling system.
14 : : *
15 : : * Revoke is the mechanism used to prevent old log records for deleted
16 : : * metadata from being replayed on top of newer data using the same
17 : : * blocks. The revoke mechanism is used in two separate places:
18 : : *
19 : : * + Commit: during commit we write the entire list of the current
20 : : * transaction's revoked blocks to the journal
21 : : *
22 : : * + Recovery: during recovery we record the transaction ID of all
23 : : * revoked blocks. If there are multiple revoke records in the log
24 : : * for a single block, only the last one counts, and if there is a log
25 : : * entry for a block beyond the last revoke, then that log entry still
26 : : * gets replayed.
27 : : *
28 : : * We can get interactions between revokes and new log data within a
29 : : * single transaction:
30 : : *
31 : : * Block is revoked and then journaled:
32 : : * The desired end result is the journaling of the new block, so we
33 : : * cancel the revoke before the transaction commits.
34 : : *
35 : : * Block is journaled and then revoked:
36 : : * The revoke must take precedence over the write of the block, so we
37 : : * need either to cancel the journal entry or to write the revoke
38 : : * later in the log than the log block. In this case, we choose the
39 : : * latter: journaling a block cancels any revoke record for that block
40 : : * in the current transaction, so any revoke for that block in the
41 : : * transaction must have happened after the block was journaled and so
42 : : * the revoke must take precedence.
43 : : *
44 : : * Block is revoked and then written as data:
45 : : * The data write is allowed to succeed, but the revoke is _not_
46 : : * cancelled. We still need to prevent old log records from
47 : : * overwriting the new data. We don't even need to clear the revoke
48 : : * bit here.
49 : : *
50 : : * We cache revoke status of a buffer in the current transaction in b_states
51 : : * bits. As the name says, revokevalid flag indicates that the cached revoke
52 : : * status of a buffer is valid and we can rely on the cached status.
53 : : *
54 : : * Revoke information on buffers is a tri-state value:
55 : : *
56 : : * RevokeValid clear: no cached revoke status, need to look it up
57 : : * RevokeValid set, Revoked clear:
58 : : * buffer has not been revoked, and cancel_revoke
59 : : * need do nothing.
60 : : * RevokeValid set, Revoked set:
61 : : * buffer has been revoked.
62 : : *
63 : : * Locking rules:
64 : : * We keep two hash tables of revoke records. One hashtable belongs to the
65 : : * running transaction (is pointed to by journal->j_revoke), the other one
66 : : * belongs to the committing transaction. Accesses to the second hash table
67 : : * happen only from the kjournald and no other thread touches this table. Also
68 : : * journal_switch_revoke_table() which switches which hashtable belongs to the
69 : : * running and which to the committing transaction is called only from
70 : : * kjournald. Therefore we need no locks when accessing the hashtable belonging
71 : : * to the committing transaction.
72 : : *
73 : : * All users operating on the hash table belonging to the running transaction
74 : : * have a handle to the transaction. Therefore they are safe from kjournald
75 : : * switching hash tables under them. For operations on the lists of entries in
76 : : * the hash table j_revoke_lock is used.
77 : : *
78 : : * Finally, also replay code uses the hash tables but at this moment no one else
79 : : * can touch them (filesystem isn't mounted yet) and hence no locking is
80 : : * needed.
81 : : */
82 : :
83 : : #ifndef __KERNEL__
84 : : #include "jfs_user.h"
85 : : #else
86 : : #include <linux/time.h>
87 : : #include <linux/fs.h>
88 : : #include <linux/jbd2.h>
89 : : #include <linux/errno.h>
90 : : #include <linux/slab.h>
91 : : #include <linux/list.h>
92 : : #include <linux/init.h>
93 : : #include <linux/bio.h>
94 : : #endif
95 : : #include <linux/log2.h>
96 : :
97 : : static struct kmem_cache *jbd2_revoke_record_cache;
98 : : static struct kmem_cache *jbd2_revoke_table_cache;
99 : :
100 : : /* Each revoke record represents one single revoked block. During
101 : : journal replay, this involves recording the transaction ID of the
102 : : last transaction to revoke this block. */
103 : :
104 : : struct jbd2_revoke_record_s
105 : : {
106 : : struct list_head hash;
107 : : tid_t sequence; /* Used for recovery only */
108 : : unsigned long long blocknr;
109 : : };
110 : :
111 : :
112 : : /* The revoke table is just a simple hash table of revoke records. */
113 : : struct jbd2_revoke_table_s
114 : : {
115 : : /* It is conceivable that we might want a larger hash table
116 : : * for recovery. Must be a power of two. */
117 : : int hash_size;
118 : : int hash_shift;
119 : : struct list_head *hash_table;
120 : : };
121 : :
122 : :
123 : : #ifdef __KERNEL__
124 : : static void write_one_revoke_record(journal_t *, transaction_t *,
125 : : struct list_head *,
126 : : struct buffer_head **, int *,
127 : : struct jbd2_revoke_record_s *, int);
128 : : static void flush_descriptor(journal_t *, struct buffer_head *, int, int);
129 : : #endif
130 : :
131 : : /* Utility functions to maintain the revoke table */
132 : :
133 : : /* Borrowed from buffer.c: this is a tried and tested block hash function */
134 : : static inline int hash(journal_t *journal, unsigned long long block)
135 : : {
136 : : struct jbd2_revoke_table_s *table = journal->j_revoke;
137 : 75321 : int hash_shift = table->hash_shift;
138 : 75321 : int hash = (int)block ^ (int)((block >> 31) >> 1);
139 : :
140 : 225963 : return ((hash << (hash_shift - 6)) ^
141 : 150642 : (hash >> 13) ^
142 : 150642 : (hash << (hash_shift - 12))) & (table->hash_size - 1);
143 : : }
144 : :
145 : 42770 : static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr,
146 : : tid_t seq)
147 : : {
148 : : struct list_head *hash_list;
149 : : struct jbd2_revoke_record_s *record;
150 : :
151 : : repeat:
152 : 42770 : record = kmem_cache_alloc(jbd2_revoke_record_cache, GFP_NOFS);
153 [ + - ]: 42770 : if (!record)
154 : : goto oom;
155 : :
156 : 42770 : record->sequence = seq;
157 : 42770 : record->blocknr = blocknr;
158 : 85540 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
159 : : spin_lock(&journal->j_revoke_lock);
160 : 42770 : list_add(&record->hash, hash_list);
161 : : spin_unlock(&journal->j_revoke_lock);
162 : : return 0;
163 : :
164 : : oom:
165 : : if (!journal_oom_retry)
166 : : return -ENOMEM;
167 : : jbd_debug(1, "ENOMEM in %s, retrying\n", __func__);
168 : 0 : yield();
169 : 0 : goto repeat;
170 : : }
171 : :
172 : : /* Find a revoke record in the journal's hash table. */
173 : :
174 : 0 : static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal,
175 : : unsigned long long blocknr)
176 : : {
177 : : struct list_head *hash_list;
178 : : struct jbd2_revoke_record_s *record;
179 : :
180 : 65102 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
181 : :
182 : : spin_lock(&journal->j_revoke_lock);
183 : 32551 : record = (struct jbd2_revoke_record_s *) hash_list->next;
184 [ + + ]: 834020 : while (&(record->hash) != hash_list) {
185 [ - + ]: 768918 : if (record->blocknr == blocknr) {
186 : : spin_unlock(&journal->j_revoke_lock);
187 : 0 : return record;
188 : : }
189 : 768918 : record = (struct jbd2_revoke_record_s *) record->hash.next;
190 : : }
191 : : spin_unlock(&journal->j_revoke_lock);
192 : 32551 : return NULL;
193 : : }
194 : :
195 : 0 : void jbd2_journal_destroy_revoke_caches(void)
196 : : {
197 [ # # ]: 0 : if (jbd2_revoke_record_cache) {
198 : 0 : kmem_cache_destroy(jbd2_revoke_record_cache);
199 : 0 : jbd2_revoke_record_cache = NULL;
200 : : }
201 [ # # ]: 0 : if (jbd2_revoke_table_cache) {
202 : 0 : kmem_cache_destroy(jbd2_revoke_table_cache);
203 : 0 : jbd2_revoke_table_cache = NULL;
204 : : }
205 : 0 : }
206 : :
207 : 0 : int __init jbd2_journal_init_revoke_caches(void)
208 : : {
209 [ # # ]: 0 : J_ASSERT(!jbd2_revoke_record_cache);
210 [ # # ]: 0 : J_ASSERT(!jbd2_revoke_table_cache);
211 : :
212 : 0 : jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
213 : : SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
214 [ # # ]: 0 : if (!jbd2_revoke_record_cache)
215 : : goto record_cache_failure;
216 : :
217 : 0 : jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
218 : : SLAB_TEMPORARY);
219 [ # # ]: 0 : if (!jbd2_revoke_table_cache)
220 : : goto table_cache_failure;
221 : : return 0;
222 : : table_cache_failure:
223 : 0 : jbd2_journal_destroy_revoke_caches();
224 : : record_cache_failure:
225 : : return -ENOMEM;
226 : : }
227 : :
228 : 0 : static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size)
229 : : {
230 : : int shift = 0;
231 : : int tmp = hash_size;
232 : : struct jbd2_revoke_table_s *table;
233 : :
234 : 0 : table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL);
235 [ # # ]: 0 : if (!table)
236 : : goto out;
237 : :
238 [ # # ]: 0 : while((tmp >>= 1UL) != 0UL)
239 : 0 : shift++;
240 : :
241 : 0 : table->hash_size = hash_size;
242 : 0 : table->hash_shift = shift;
243 : 0 : table->hash_table =
244 : 0 : kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL);
245 [ # # ]: 0 : if (!table->hash_table) {
246 : 0 : kmem_cache_free(jbd2_revoke_table_cache, table);
247 : : table = NULL;
248 : 0 : goto out;
249 : : }
250 : :
251 [ # # ]: 0 : for (tmp = 0; tmp < hash_size; tmp++)
252 : 0 : INIT_LIST_HEAD(&table->hash_table[tmp]);
253 : :
254 : : out:
255 : 0 : return table;
256 : : }
257 : :
258 : 0 : static void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table)
259 : : {
260 : : int i;
261 : : struct list_head *hash_list;
262 : :
263 [ # # ]: 0 : for (i = 0; i < table->hash_size; i++) {
264 : 0 : hash_list = &table->hash_table[i];
265 [ # # ]: 0 : J_ASSERT(list_empty(hash_list));
266 : : }
267 : :
268 : 0 : kfree(table->hash_table);
269 : 0 : kmem_cache_free(jbd2_revoke_table_cache, table);
270 : 0 : }
271 : :
272 : : /* Initialise the revoke table for a given journal to a given size. */
273 : 0 : int jbd2_journal_init_revoke(journal_t *journal, int hash_size)
274 : : {
275 [ # # ]: 0 : J_ASSERT(journal->j_revoke_table[0] == NULL);
276 [ # # ]: 0 : J_ASSERT(is_power_of_2(hash_size));
277 : :
278 : 0 : journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size);
279 [ # # ]: 0 : if (!journal->j_revoke_table[0])
280 : : goto fail0;
281 : :
282 : 0 : journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size);
283 [ # # ]: 0 : if (!journal->j_revoke_table[1])
284 : : goto fail1;
285 : :
286 : 0 : journal->j_revoke = journal->j_revoke_table[1];
287 : :
288 : 0 : spin_lock_init(&journal->j_revoke_lock);
289 : :
290 : 0 : return 0;
291 : :
292 : : fail1:
293 : 0 : jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
294 : : fail0:
295 : : return -ENOMEM;
296 : : }
297 : :
298 : : /* Destroy a journal's revoke table. The table must already be empty! */
299 : 0 : void jbd2_journal_destroy_revoke(journal_t *journal)
300 : : {
301 : 0 : journal->j_revoke = NULL;
302 [ # # ]: 0 : if (journal->j_revoke_table[0])
303 : 0 : jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
304 [ # # ]: 0 : if (journal->j_revoke_table[1])
305 : 0 : jbd2_journal_destroy_revoke_table(journal->j_revoke_table[1]);
306 : 0 : }
307 : :
308 : :
309 : : #ifdef __KERNEL__
310 : :
311 : : /*
312 : : * jbd2_journal_revoke: revoke a given buffer_head from the journal. This
313 : : * prevents the block from being replayed during recovery if we take a
314 : : * crash after this current transaction commits. Any subsequent
315 : : * metadata writes of the buffer in this transaction cancel the
316 : : * revoke.
317 : : *
318 : : * Note that this call may block --- it is up to the caller to make
319 : : * sure that there are no further calls to journal_write_metadata
320 : : * before the revoke is complete. In ext3, this implies calling the
321 : : * revoke before clearing the block bitmap when we are deleting
322 : : * metadata.
323 : : *
324 : : * Revoke performs a jbd2_journal_forget on any buffer_head passed in as a
325 : : * parameter, but does _not_ forget the buffer_head if the bh was only
326 : : * found implicitly.
327 : : *
328 : : * bh_in may not be a journalled buffer - it may have come off
329 : : * the hash tables without an attached journal_head.
330 : : *
331 : : * If bh_in is non-zero, jbd2_journal_revoke() will decrement its b_count
332 : : * by one.
333 : : */
334 : :
335 : 0 : int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr,
336 : : struct buffer_head *bh_in)
337 : : {
338 : : struct buffer_head *bh = NULL;
339 : : journal_t *journal;
340 : : struct block_device *bdev;
341 : : int err;
342 : :
343 : : might_sleep();
344 : : if (bh_in)
345 : : BUFFER_TRACE(bh_in, "enter");
346 : :
347 : 42770 : journal = handle->h_transaction->t_journal;
348 [ - + ]: 42770 : if (!jbd2_journal_set_features(journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)){
349 : 0 : J_ASSERT (!"Cannot set revoke feature!");
350 : : return -EINVAL;
351 : : }
352 : :
353 : 42770 : bdev = journal->j_fs_dev;
354 : : bh = bh_in;
355 : :
356 [ - + ]: 42770 : if (!bh) {
357 : 0 : bh = __find_get_block(bdev, blocknr, journal->j_blocksize);
358 : : if (bh)
359 : : BUFFER_TRACE(bh, "found on hash");
360 : : }
361 : : #ifdef JBD2_EXPENSIVE_CHECKING
362 : : else {
363 : : struct buffer_head *bh2;
364 : :
365 : : /* If there is a different buffer_head lying around in
366 : : * memory anywhere... */
367 : : bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize);
368 : : if (bh2) {
369 : : /* ... and it has RevokeValid status... */
370 : : if (bh2 != bh && buffer_revokevalid(bh2))
371 : : /* ...then it better be revoked too,
372 : : * since it's illegal to create a revoke
373 : : * record against a buffer_head which is
374 : : * not marked revoked --- that would
375 : : * risk missing a subsequent revoke
376 : : * cancel. */
377 : : J_ASSERT_BH(bh2, buffer_revoked(bh2));
378 : : put_bh(bh2);
379 : : }
380 : : }
381 : : #endif
382 : :
383 : : /* We really ought not ever to revoke twice in a row without
384 : : first having the revoke cancelled: it's illegal to free a
385 : : block twice without allocating it in between! */
386 [ + - ]: 42770 : if (bh) {
387 [ - + ][ - + ]: 42770 : if (!J_EXPECT_BH(bh, !buffer_revoked(bh),
388 : : "inconsistent data on disk")) {
389 [ # # ]: 0 : if (!bh_in)
390 : : brelse(bh);
391 : : return -EIO;
392 : : }
393 : : set_buffer_revoked(bh);
394 : : set_buffer_revokevalid(bh);
395 [ + - ]: 42770 : if (bh_in) {
396 : : BUFFER_TRACE(bh_in, "call jbd2_journal_forget");
397 : 42770 : jbd2_journal_forget(handle, bh_in);
398 : : } else {
399 : : BUFFER_TRACE(bh, "call brelse");
400 : 0 : __brelse(bh);
401 : : }
402 : : }
403 : :
404 : : jbd_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in);
405 : 42770 : err = insert_revoke_hash(journal, blocknr,
406 : 42770 : handle->h_transaction->t_tid);
407 : : BUFFER_TRACE(bh_in, "exit");
408 : 42770 : return err;
409 : : }
410 : :
411 : : /*
412 : : * Cancel an outstanding revoke. For use only internally by the
413 : : * journaling code (called from jbd2_journal_get_write_access).
414 : : *
415 : : * We trust buffer_revoked() on the buffer if the buffer is already
416 : : * being journaled: if there is no revoke pending on the buffer, then we
417 : : * don't do anything here.
418 : : *
419 : : * This would break if it were possible for a buffer to be revoked and
420 : : * discarded, and then reallocated within the same transaction. In such
421 : : * a case we would have lost the revoked bit, but when we arrived here
422 : : * the second time we would still have a pending revoke to cancel. So,
423 : : * do not trust the Revoked bit on buffers unless RevokeValid is also
424 : : * set.
425 : : */
426 : 0 : int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
427 : : {
428 : : struct jbd2_revoke_record_s *record;
429 : 16066809 : journal_t *journal = handle->h_transaction->t_journal;
430 : : int need_cancel;
431 : : int did_revoke = 0; /* akpm: debug */
432 : : struct buffer_head *bh = jh2bh(jh);
433 : :
434 : : jbd_debug(4, "journal_head %p, cancelling revoke\n", jh);
435 : :
436 : : /* Is the existing Revoke bit valid? If so, we trust it, and
437 : : * only perform the full cancel if the revoke bit is set. If
438 : : * not, we can't trust the revoke bit, and we need to do the
439 : : * full search for a revoke record. */
440 [ + + ]: 16066568 : if (test_set_buffer_revokevalid(bh)) {
441 : : need_cancel = test_clear_buffer_revoked(bh);
442 : : } else {
443 : : need_cancel = 1;
444 : : clear_buffer_revoked(bh);
445 : : }
446 : :
447 [ + + ]: 16066727 : if (need_cancel) {
448 : 32551 : record = find_revoke_record(journal, bh->b_blocknr);
449 [ - + ]: 32551 : if (record) {
450 : : jbd_debug(4, "cancelled existing revoke on "
451 : : "blocknr %llu\n", (unsigned long long)bh->b_blocknr);
452 : : spin_lock(&journal->j_revoke_lock);
453 : : list_del(&record->hash);
454 : : spin_unlock(&journal->j_revoke_lock);
455 : 0 : kmem_cache_free(jbd2_revoke_record_cache, record);
456 : : did_revoke = 1;
457 : : }
458 : : }
459 : :
460 : : #ifdef JBD2_EXPENSIVE_CHECKING
461 : : /* There better not be one left behind by now! */
462 : : record = find_revoke_record(journal, bh->b_blocknr);
463 : : J_ASSERT_JH(jh, record == NULL);
464 : : #endif
465 : :
466 : : /* Finally, have we just cleared revoke on an unhashed
467 : : * buffer_head? If so, we'd better make sure we clear the
468 : : * revoked status on any hashed alias too, otherwise the revoke
469 : : * state machine will get very upset later on. */
470 [ + + ]: 16066727 : if (need_cancel) {
471 : : struct buffer_head *bh2;
472 : 32551 : bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size);
473 [ + + ]: 32551 : if (bh2) {
474 [ + + ]: 25693 : if (bh2 != bh)
475 : : clear_buffer_revoked(bh2);
476 : 25693 : __brelse(bh2);
477 : : }
478 : : }
479 : 16066727 : return did_revoke;
480 : : }
481 : :
482 : : /*
483 : : * journal_clear_revoked_flag clears revoked flag of buffers in
484 : : * revoke table to reflect there is no revoked buffers in the next
485 : : * transaction which is going to be started.
486 : : */
487 : 0 : void jbd2_clear_buffer_revoked_flags(journal_t *journal)
488 : : {
489 : 20656 : struct jbd2_revoke_table_s *revoke = journal->j_revoke;
490 : : int i = 0;
491 : :
492 [ + + ]: 5308592 : for (i = 0; i < revoke->hash_size; i++) {
493 : : struct list_head *hash_list;
494 : : struct list_head *list_entry;
495 : 5287936 : hash_list = &revoke->hash_table[i];
496 : :
497 [ + + ]: 5351362 : list_for_each(list_entry, hash_list) {
498 : : struct jbd2_revoke_record_s *record;
499 : : struct buffer_head *bh;
500 : : record = (struct jbd2_revoke_record_s *)list_entry;
501 : 42770 : bh = __find_get_block(journal->j_fs_dev,
502 : : record->blocknr,
503 : 42770 : journal->j_blocksize);
504 [ + - ]: 42770 : if (bh) {
505 : : clear_buffer_revoked(bh);
506 : 42770 : __brelse(bh);
507 : : }
508 : : }
509 : : }
510 : 20656 : }
511 : :
512 : : /* journal_switch_revoke table select j_revoke for next transaction
513 : : * we do not want to suspend any processing until all revokes are
514 : : * written -bzzz
515 : : */
516 : 0 : void jbd2_journal_switch_revoke_table(journal_t *journal)
517 : : {
518 : : int i;
519 : :
520 [ + + ]: 20656 : if (journal->j_revoke == journal->j_revoke_table[0])
521 : 20656 : journal->j_revoke = journal->j_revoke_table[1];
522 : : else
523 : 10328 : journal->j_revoke = journal->j_revoke_table[0];
524 : :
525 [ + + ]: 5308592 : for (i = 0; i < journal->j_revoke->hash_size; i++)
526 : 5287936 : INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]);
527 : 20656 : }
528 : :
529 : : /*
530 : : * Write revoke records to the journal for all entries in the current
531 : : * revoke hash, deleting the entries as we go.
532 : : */
533 : 0 : void jbd2_journal_write_revoke_records(journal_t *journal,
534 : : transaction_t *transaction,
535 : : struct list_head *log_bufs,
536 : : int write_op)
537 : : {
538 : : struct buffer_head *descriptor;
539 : : struct jbd2_revoke_record_s *record;
540 : : struct jbd2_revoke_table_s *revoke;
541 : : struct list_head *hash_list;
542 : : int i, offset, count;
543 : :
544 : 20656 : descriptor = NULL;
545 : 20656 : offset = 0;
546 : : count = 0;
547 : :
548 : : /* select revoke table for committing transaction */
549 : 20656 : revoke = journal->j_revoke == journal->j_revoke_table[0] ?
550 [ + + ]: 20656 : journal->j_revoke_table[1] : journal->j_revoke_table[0];
551 : :
552 [ + + ]: 5308592 : for (i = 0; i < revoke->hash_size; i++) {
553 : 5287936 : hash_list = &revoke->hash_table[i];
554 : :
555 [ + + ]: 5330706 : while (!list_empty(hash_list)) {
556 : : record = (struct jbd2_revoke_record_s *)
557 : : hash_list->next;
558 : 42770 : write_one_revoke_record(journal, transaction, log_bufs,
559 : : &descriptor, &offset,
560 : : record, write_op);
561 : : count++;
562 : : list_del(&record->hash);
563 : 42770 : kmem_cache_free(jbd2_revoke_record_cache, record);
564 : : }
565 : : }
566 [ + + ]: 20656 : if (descriptor)
567 : 576 : flush_descriptor(journal, descriptor, offset, write_op);
568 : : jbd_debug(1, "Wrote %d revoke records\n", count);
569 : 20656 : }
570 : :
571 : : /*
572 : : * Write out one revoke record. We need to create a new descriptor
573 : : * block if the old one is full or if we have not already created one.
574 : : */
575 : :
576 : 0 : static void write_one_revoke_record(journal_t *journal,
577 : : transaction_t *transaction,
578 : : struct list_head *log_bufs,
579 : : struct buffer_head **descriptorp,
580 : : int *offsetp,
581 : : struct jbd2_revoke_record_s *record,
582 : : int write_op)
583 : : {
584 : : int csum_size = 0;
585 : : struct buffer_head *descriptor;
586 : : int offset;
587 : : journal_header_t *header;
588 : :
589 : : /* If we are already aborting, this all becomes a noop. We
590 : : still need to go round the loop in
591 : : jbd2_journal_write_revoke_records in order to free all of the
592 : : revoke records: only the IO to the journal is omitted. */
593 [ + - ]: 42770 : if (is_journal_aborted(journal))
594 : : return;
595 : :
596 : 42770 : descriptor = *descriptorp;
597 : 42770 : offset = *offsetp;
598 : :
599 : : /* Do we need to leave space at the end for a checksum? */
600 [ + - ][ - + ]: 42770 : if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
601 : : csum_size = sizeof(struct jbd2_journal_revoke_tail);
602 : :
603 : : /* Make sure we have a descriptor with space left for the record */
604 [ + + ]: 42770 : if (descriptor) {
605 [ + + ]: 42194 : if (offset >= journal->j_blocksize - csum_size) {
606 : 34 : flush_descriptor(journal, descriptor, offset, write_op);
607 : : descriptor = NULL;
608 : : }
609 : : }
610 : :
611 [ + + ]: 85540 : if (!descriptor) {
612 : 610 : descriptor = jbd2_journal_get_descriptor_buffer(journal);
613 [ + - ]: 610 : if (!descriptor)
614 : : return;
615 : 610 : header = (journal_header_t *)descriptor->b_data;
616 : 610 : header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
617 : 610 : header->h_blocktype = cpu_to_be32(JBD2_REVOKE_BLOCK);
618 [ - + ]: 610 : header->h_sequence = cpu_to_be32(transaction->t_tid);
619 : :
620 : : /* Record it so that we can wait for IO completion later */
621 : : BUFFER_TRACE(descriptor, "file in log_bufs");
622 : : jbd2_file_log_bh(log_bufs, descriptor);
623 : :
624 : : offset = sizeof(jbd2_journal_revoke_header_t);
625 : 610 : *descriptorp = descriptor;
626 : : }
627 : :
628 [ + - ][ - + ]: 85540 : if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) {
629 : 0 : * ((__be64 *)(&descriptor->b_data[offset])) =
630 [ # # ]: 0 : cpu_to_be64(record->blocknr);
631 : 0 : offset += 8;
632 : :
633 : : } else {
634 : 85540 : * ((__be32 *)(&descriptor->b_data[offset])) =
635 [ - + ]: 42770 : cpu_to_be32(record->blocknr);
636 : 42770 : offset += 4;
637 : : }
638 : :
639 : 42770 : *offsetp = offset;
640 : : }
641 : :
642 : 0 : static void jbd2_revoke_csum_set(journal_t *j, struct buffer_head *bh)
643 : : {
644 : : struct jbd2_journal_revoke_tail *tail;
645 : : __u32 csum;
646 : :
647 [ + - ][ - + ]: 610 : if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
648 : 610 : return;
649 : :
650 : 0 : tail = (struct jbd2_journal_revoke_tail *)(bh->b_data + j->j_blocksize -
651 : : sizeof(struct jbd2_journal_revoke_tail));
652 : 0 : tail->r_checksum = 0;
653 : 0 : csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
654 [ # # ]: 610 : tail->r_checksum = cpu_to_be32(csum);
655 : : }
656 : :
657 : : /*
658 : : * Flush a revoke descriptor out to the journal. If we are aborting,
659 : : * this is a noop; otherwise we are generating a buffer which needs to
660 : : * be waited for during commit, so it has to go onto the appropriate
661 : : * journal buffer list.
662 : : */
663 : :
664 : 0 : static void flush_descriptor(journal_t *journal,
665 : : struct buffer_head *descriptor,
666 : : int offset, int write_op)
667 : : {
668 : : jbd2_journal_revoke_header_t *header;
669 : :
670 [ - + ]: 610 : if (is_journal_aborted(journal)) {
671 : : put_bh(descriptor);
672 : 610 : return;
673 : : }
674 : :
675 : 610 : header = (jbd2_journal_revoke_header_t *)descriptor->b_data;
676 [ - + ]: 610 : header->r_count = cpu_to_be32(offset);
677 : 610 : jbd2_revoke_csum_set(journal, descriptor);
678 : :
679 : : set_buffer_jwrite(descriptor);
680 : : BUFFER_TRACE(descriptor, "write");
681 : : set_buffer_dirty(descriptor);
682 : 610 : write_dirty_buffer(descriptor, write_op);
683 : : }
684 : : #endif
685 : :
686 : : /*
687 : : * Revoke support for recovery.
688 : : *
689 : : * Recovery needs to be able to:
690 : : *
691 : : * record all revoke records, including the tid of the latest instance
692 : : * of each revoke in the journal
693 : : *
694 : : * check whether a given block in a given transaction should be replayed
695 : : * (ie. has not been revoked by a revoke record in that or a subsequent
696 : : * transaction)
697 : : *
698 : : * empty the revoke table after recovery.
699 : : */
700 : :
701 : : /*
702 : : * First, setting revoke records. We create a new revoke record for
703 : : * every block ever revoked in the log as we scan it for recovery, and
704 : : * we update the existing records if we find multiple revokes for a
705 : : * single block.
706 : : */
707 : :
708 : 0 : int jbd2_journal_set_revoke(journal_t *journal,
709 : : unsigned long long blocknr,
710 : : tid_t sequence)
711 : : {
712 : : struct jbd2_revoke_record_s *record;
713 : :
714 : 0 : record = find_revoke_record(journal, blocknr);
715 [ # # ]: 0 : if (record) {
716 : : /* If we have multiple occurrences, only record the
717 : : * latest sequence number in the hashed record */
718 [ # # ]: 0 : if (tid_gt(sequence, record->sequence))
719 : 0 : record->sequence = sequence;
720 : : return 0;
721 : : }
722 : 0 : return insert_revoke_hash(journal, blocknr, sequence);
723 : : }
724 : :
725 : : /*
726 : : * Test revoke records. For a given block referenced in the log, has
727 : : * that block been revoked? A revoke record with a given transaction
728 : : * sequence number revokes all blocks in that transaction and earlier
729 : : * ones, but later transactions still need replayed.
730 : : */
731 : :
732 : 0 : int jbd2_journal_test_revoke(journal_t *journal,
733 : : unsigned long long blocknr,
734 : : tid_t sequence)
735 : : {
736 : : struct jbd2_revoke_record_s *record;
737 : :
738 : 0 : record = find_revoke_record(journal, blocknr);
739 [ # # ]: 0 : if (!record)
740 : : return 0;
741 [ # # ]: 0 : if (tid_gt(sequence, record->sequence))
742 : : return 0;
743 : 0 : return 1;
744 : : }
745 : :
746 : : /*
747 : : * Finally, once recovery is over, we need to clear the revoke table so
748 : : * that it can be reused by the running filesystem.
749 : : */
750 : :
751 : 0 : void jbd2_journal_clear_revoke(journal_t *journal)
752 : : {
753 : : int i;
754 : : struct list_head *hash_list;
755 : : struct jbd2_revoke_record_s *record;
756 : : struct jbd2_revoke_table_s *revoke;
757 : :
758 : 0 : revoke = journal->j_revoke;
759 : :
760 [ # # ]: 0 : for (i = 0; i < revoke->hash_size; i++) {
761 : 0 : hash_list = &revoke->hash_table[i];
762 [ # # ]: 0 : while (!list_empty(hash_list)) {
763 : : record = (struct jbd2_revoke_record_s*) hash_list->next;
764 : : list_del(&record->hash);
765 : 0 : kmem_cache_free(jbd2_revoke_record_cache, record);
766 : : }
767 : : }
768 : 0 : }
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