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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 : 3 : static inline int hash(journal_t *journal, unsigned long long block)
132 : : {
133 : 3 : return hash_64(block, journal->j_revoke->hash_shift);
134 : : }
135 : :
136 : 3 : static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr,
137 : : tid_t seq)
138 : : {
139 : : struct list_head *hash_list;
140 : : struct jbd2_revoke_record_s *record;
141 : : gfp_t gfp_mask = GFP_NOFS;
142 : :
143 : : if (journal_oom_retry)
144 : : gfp_mask |= __GFP_NOFAIL;
145 : 3 : record = kmem_cache_alloc(jbd2_revoke_record_cache, gfp_mask);
146 : 3 : if (!record)
147 : : return -ENOMEM;
148 : :
149 : 3 : record->sequence = seq;
150 : 3 : record->blocknr = blocknr;
151 : 3 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
152 : : spin_lock(&journal->j_revoke_lock);
153 : 3 : list_add(&record->hash, hash_list);
154 : : spin_unlock(&journal->j_revoke_lock);
155 : 3 : return 0;
156 : : }
157 : :
158 : : /* Find a revoke record in the journal's hash table. */
159 : :
160 : 3 : static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal,
161 : : unsigned long long blocknr)
162 : : {
163 : : struct list_head *hash_list;
164 : : struct jbd2_revoke_record_s *record;
165 : :
166 : 3 : hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
167 : :
168 : : spin_lock(&journal->j_revoke_lock);
169 : 3 : record = (struct jbd2_revoke_record_s *) hash_list->next;
170 : 3 : while (&(record->hash) != hash_list) {
171 : 3 : if (record->blocknr == blocknr) {
172 : : spin_unlock(&journal->j_revoke_lock);
173 : 1 : return record;
174 : : }
175 : 3 : record = (struct jbd2_revoke_record_s *) record->hash.next;
176 : : }
177 : : spin_unlock(&journal->j_revoke_lock);
178 : 3 : 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 : 3 : int __init jbd2_journal_init_revoke_record_cache(void)
194 : : {
195 : 3 : J_ASSERT(!jbd2_revoke_record_cache);
196 : 3 : jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
197 : : SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
198 : :
199 : 3 : 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 : 3 : int __init jbd2_journal_init_revoke_table_cache(void)
207 : : {
208 : 3 : J_ASSERT(!jbd2_revoke_table_cache);
209 : 3 : jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
210 : : SLAB_TEMPORARY);
211 : 3 : 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 : 3 : static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size)
219 : : {
220 : : int shift = 0;
221 : : int tmp = hash_size;
222 : : struct jbd2_revoke_table_s *table;
223 : :
224 : 3 : table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL);
225 : 3 : if (!table)
226 : : goto out;
227 : :
228 : 3 : while((tmp >>= 1UL) != 0UL)
229 : 3 : shift++;
230 : :
231 : 3 : table->hash_size = hash_size;
232 : 3 : table->hash_shift = shift;
233 : 3 : table->hash_table =
234 : 3 : kmalloc_array(hash_size, sizeof(struct list_head), GFP_KERNEL);
235 : 3 : if (!table->hash_table) {
236 : 0 : kmem_cache_free(jbd2_revoke_table_cache, table);
237 : : table = NULL;
238 : 0 : goto out;
239 : : }
240 : :
241 : 3 : for (tmp = 0; tmp < hash_size; tmp++)
242 : 3 : INIT_LIST_HEAD(&table->hash_table[tmp]);
243 : :
244 : : out:
245 : 3 : return table;
246 : : }
247 : :
248 : 0 : static void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table)
249 : : {
250 : : int i;
251 : : 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 : 3 : int jbd2_journal_init_revoke(journal_t *journal, int hash_size)
264 : : {
265 : 3 : J_ASSERT(journal->j_revoke_table[0] == NULL);
266 : 3 : J_ASSERT(is_power_of_2(hash_size));
267 : :
268 : 3 : journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size);
269 : 3 : if (!journal->j_revoke_table[0])
270 : : goto fail0;
271 : :
272 : 3 : journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size);
273 : 3 : if (!journal->j_revoke_table[1])
274 : : goto fail1;
275 : :
276 : 3 : journal->j_revoke = journal->j_revoke_table[1];
277 : :
278 : 3 : spin_lock_init(&journal->j_revoke_lock);
279 : :
280 : 3 : 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 : 3 : int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr,
327 : : struct buffer_head *bh_in)
328 : : {
329 : : struct buffer_head *bh = NULL;
330 : : journal_t *journal;
331 : : struct block_device *bdev;
332 : : int err;
333 : :
334 : 3 : might_sleep();
335 : : if (bh_in)
336 : : BUFFER_TRACE(bh_in, "enter");
337 : :
338 : 3 : journal = handle->h_transaction->t_journal;
339 : 3 : 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 : 3 : bdev = journal->j_fs_dev;
345 : : bh = bh_in;
346 : :
347 : 3 : if (!bh) {
348 : 0 : bh = __find_get_block(bdev, blocknr, journal->j_blocksize);
349 : : if (bh)
350 : : 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 : : /* We really ought not ever to revoke twice in a row without
375 : : first having the revoke cancelled: it's illegal to free a
376 : : block twice without allocating it in between! */
377 : 3 : if (bh) {
378 : 3 : if (!J_EXPECT_BH(bh, !buffer_revoked(bh),
379 : : "inconsistent data on disk")) {
380 : 0 : if (!bh_in)
381 : : brelse(bh);
382 : : return -EIO;
383 : : }
384 : : set_buffer_revoked(bh);
385 : : set_buffer_revokevalid(bh);
386 : 3 : if (bh_in) {
387 : : BUFFER_TRACE(bh_in, "call jbd2_journal_forget");
388 : 3 : jbd2_journal_forget(handle, bh_in);
389 : : } else {
390 : : BUFFER_TRACE(bh, "call brelse");
391 : 0 : __brelse(bh);
392 : : }
393 : : }
394 : :
395 : : jbd_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in);
396 : 3 : err = insert_revoke_hash(journal, blocknr,
397 : 3 : handle->h_transaction->t_tid);
398 : : BUFFER_TRACE(bh_in, "exit");
399 : 3 : return err;
400 : : }
401 : :
402 : : /*
403 : : * Cancel an outstanding revoke. For use only internally by the
404 : : * journaling code (called from jbd2_journal_get_write_access).
405 : : *
406 : : * We trust buffer_revoked() on the buffer if the buffer is already
407 : : * being journaled: if there is no revoke pending on the buffer, then we
408 : : * don't do anything here.
409 : : *
410 : : * This would break if it were possible for a buffer to be revoked and
411 : : * discarded, and then reallocated within the same transaction. In such
412 : : * a case we would have lost the revoked bit, but when we arrived here
413 : : * the second time we would still have a pending revoke to cancel. So,
414 : : * do not trust the Revoked bit on buffers unless RevokeValid is also
415 : : * set.
416 : : */
417 : 3 : int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
418 : : {
419 : : struct jbd2_revoke_record_s *record;
420 : 3 : journal_t *journal = handle->h_transaction->t_journal;
421 : : int need_cancel;
422 : : int did_revoke = 0; /* akpm: debug */
423 : : struct buffer_head *bh = jh2bh(jh);
424 : :
425 : : jbd_debug(4, "journal_head %p, cancelling revoke\n", jh);
426 : :
427 : : /* Is the existing Revoke bit valid? If so, we trust it, and
428 : : * only perform the full cancel if the revoke bit is set. If
429 : : * not, we can't trust the revoke bit, and we need to do the
430 : : * full search for a revoke record. */
431 : 3 : if (test_set_buffer_revokevalid(bh)) {
432 : : need_cancel = test_clear_buffer_revoked(bh);
433 : : } else {
434 : : need_cancel = 1;
435 : : clear_buffer_revoked(bh);
436 : : }
437 : :
438 : 3 : if (need_cancel) {
439 : 3 : record = find_revoke_record(journal, bh->b_blocknr);
440 : 3 : if (record) {
441 : : jbd_debug(4, "cancelled existing revoke on "
442 : : "blocknr %llu\n", (unsigned long long)bh->b_blocknr);
443 : : spin_lock(&journal->j_revoke_lock);
444 : : list_del(&record->hash);
445 : : spin_unlock(&journal->j_revoke_lock);
446 : 0 : kmem_cache_free(jbd2_revoke_record_cache, record);
447 : : did_revoke = 1;
448 : : }
449 : : }
450 : :
451 : : #ifdef JBD2_EXPENSIVE_CHECKING
452 : : /* There better not be one left behind by now! */
453 : : record = find_revoke_record(journal, bh->b_blocknr);
454 : : J_ASSERT_JH(jh, record == NULL);
455 : : #endif
456 : :
457 : : /* Finally, have we just cleared revoke on an unhashed
458 : : * buffer_head? If so, we'd better make sure we clear the
459 : : * revoked status on any hashed alias too, otherwise the revoke
460 : : * state machine will get very upset later on. */
461 : 3 : if (need_cancel) {
462 : : struct buffer_head *bh2;
463 : 3 : bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size);
464 : 3 : if (bh2) {
465 : 3 : if (bh2 != bh)
466 : : clear_buffer_revoked(bh2);
467 : 3 : __brelse(bh2);
468 : : }
469 : : }
470 : 3 : return did_revoke;
471 : : }
472 : :
473 : : /*
474 : : * journal_clear_revoked_flag clears revoked flag of buffers in
475 : : * revoke table to reflect there is no revoked buffers in the next
476 : : * transaction which is going to be started.
477 : : */
478 : 3 : void jbd2_clear_buffer_revoked_flags(journal_t *journal)
479 : : {
480 : 3 : struct jbd2_revoke_table_s *revoke = journal->j_revoke;
481 : : int i = 0;
482 : :
483 : 3 : for (i = 0; i < revoke->hash_size; i++) {
484 : : struct list_head *hash_list;
485 : : struct list_head *list_entry;
486 : 3 : hash_list = &revoke->hash_table[i];
487 : :
488 : 3 : list_for_each(list_entry, hash_list) {
489 : : struct jbd2_revoke_record_s *record;
490 : : struct buffer_head *bh;
491 : : record = (struct jbd2_revoke_record_s *)list_entry;
492 : 3 : bh = __find_get_block(journal->j_fs_dev,
493 : : record->blocknr,
494 : 3 : journal->j_blocksize);
495 : 3 : if (bh) {
496 : : clear_buffer_revoked(bh);
497 : 3 : __brelse(bh);
498 : : }
499 : : }
500 : : }
501 : 3 : }
502 : :
503 : : /* journal_switch_revoke table select j_revoke for next transaction
504 : : * we do not want to suspend any processing until all revokes are
505 : : * written -bzzz
506 : : */
507 : 3 : void jbd2_journal_switch_revoke_table(journal_t *journal)
508 : : {
509 : : int i;
510 : :
511 : 3 : if (journal->j_revoke == journal->j_revoke_table[0])
512 : 3 : journal->j_revoke = journal->j_revoke_table[1];
513 : : else
514 : 3 : journal->j_revoke = journal->j_revoke_table[0];
515 : :
516 : 3 : for (i = 0; i < journal->j_revoke->hash_size; i++)
517 : 3 : INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]);
518 : 3 : }
519 : :
520 : : /*
521 : : * Write revoke records to the journal for all entries in the current
522 : : * revoke hash, deleting the entries as we go.
523 : : */
524 : 3 : void jbd2_journal_write_revoke_records(transaction_t *transaction,
525 : : struct list_head *log_bufs)
526 : : {
527 : 3 : journal_t *journal = transaction->t_journal;
528 : : struct buffer_head *descriptor;
529 : : struct jbd2_revoke_record_s *record;
530 : : struct jbd2_revoke_table_s *revoke;
531 : : struct list_head *hash_list;
532 : : int i, offset, count;
533 : :
534 : 3 : descriptor = NULL;
535 : 3 : offset = 0;
536 : : count = 0;
537 : :
538 : : /* select revoke table for committing transaction */
539 : 3 : revoke = journal->j_revoke == journal->j_revoke_table[0] ?
540 : 3 : journal->j_revoke_table[1] : journal->j_revoke_table[0];
541 : :
542 : 3 : for (i = 0; i < revoke->hash_size; i++) {
543 : 3 : hash_list = &revoke->hash_table[i];
544 : :
545 : 3 : while (!list_empty(hash_list)) {
546 : 3 : record = (struct jbd2_revoke_record_s *)
547 : : hash_list->next;
548 : 3 : write_one_revoke_record(transaction, log_bufs,
549 : : &descriptor, &offset, record);
550 : : count++;
551 : : list_del(&record->hash);
552 : 3 : kmem_cache_free(jbd2_revoke_record_cache, record);
553 : : }
554 : : }
555 : 3 : if (descriptor)
556 : 3 : flush_descriptor(journal, descriptor, offset);
557 : : jbd_debug(1, "Wrote %d revoke records\n", count);
558 : 3 : }
559 : :
560 : : /*
561 : : * Write out one revoke record. We need to create a new descriptor
562 : : * block if the old one is full or if we have not already created one.
563 : : */
564 : :
565 : 3 : static void write_one_revoke_record(transaction_t *transaction,
566 : : struct list_head *log_bufs,
567 : : struct buffer_head **descriptorp,
568 : : int *offsetp,
569 : : struct jbd2_revoke_record_s *record)
570 : : {
571 : 3 : journal_t *journal = transaction->t_journal;
572 : : int csum_size = 0;
573 : : struct buffer_head *descriptor;
574 : : int sz, offset;
575 : :
576 : : /* If we are already aborting, this all becomes a noop. We
577 : : still need to go round the loop in
578 : : jbd2_journal_write_revoke_records in order to free all of the
579 : : revoke records: only the IO to the journal is omitted. */
580 : 3 : if (is_journal_aborted(journal))
581 : : return;
582 : :
583 : 3 : descriptor = *descriptorp;
584 : 3 : offset = *offsetp;
585 : :
586 : : /* Do we need to leave space at the end for a checksum? */
587 : 3 : if (jbd2_journal_has_csum_v2or3(journal))
588 : : csum_size = sizeof(struct jbd2_journal_block_tail);
589 : :
590 : 3 : if (jbd2_has_feature_64bit(journal))
591 : : sz = 8;
592 : : else
593 : : sz = 4;
594 : :
595 : : /* Make sure we have a descriptor with space left for the record */
596 : 3 : if (descriptor) {
597 : 3 : if (offset + sz > journal->j_blocksize - csum_size) {
598 : 0 : flush_descriptor(journal, descriptor, offset);
599 : : descriptor = NULL;
600 : : }
601 : : }
602 : :
603 : 3 : if (!descriptor) {
604 : 3 : descriptor = jbd2_journal_get_descriptor_buffer(transaction,
605 : : JBD2_REVOKE_BLOCK);
606 : 3 : if (!descriptor)
607 : : return;
608 : :
609 : : /* Record it so that we can wait for IO completion later */
610 : : BUFFER_TRACE(descriptor, "file in log_bufs");
611 : : jbd2_file_log_bh(log_bufs, descriptor);
612 : :
613 : : offset = sizeof(jbd2_journal_revoke_header_t);
614 : 3 : *descriptorp = descriptor;
615 : : }
616 : :
617 : 3 : if (jbd2_has_feature_64bit(journal))
618 : 0 : * ((__be64 *)(&descriptor->b_data[offset])) =
619 : 0 : cpu_to_be64(record->blocknr);
620 : : else
621 : 3 : * ((__be32 *)(&descriptor->b_data[offset])) =
622 : 3 : cpu_to_be32(record->blocknr);
623 : 3 : offset += sz;
624 : :
625 : 3 : *offsetp = offset;
626 : : }
627 : :
628 : : /*
629 : : * Flush a revoke descriptor out to the journal. If we are aborting,
630 : : * this is a noop; otherwise we are generating a buffer which needs to
631 : : * be waited for during commit, so it has to go onto the appropriate
632 : : * journal buffer list.
633 : : */
634 : :
635 : 3 : static void flush_descriptor(journal_t *journal,
636 : : struct buffer_head *descriptor,
637 : : int offset)
638 : : {
639 : : jbd2_journal_revoke_header_t *header;
640 : :
641 : 3 : if (is_journal_aborted(journal))
642 : 3 : return;
643 : :
644 : 3 : header = (jbd2_journal_revoke_header_t *)descriptor->b_data;
645 : 3 : header->r_count = cpu_to_be32(offset);
646 : 3 : jbd2_descriptor_block_csum_set(journal, descriptor);
647 : :
648 : : set_buffer_jwrite(descriptor);
649 : : BUFFER_TRACE(descriptor, "write");
650 : : set_buffer_dirty(descriptor);
651 : 3 : write_dirty_buffer(descriptor, REQ_SYNC);
652 : : }
653 : : #endif
654 : :
655 : : /*
656 : : * Revoke support for recovery.
657 : : *
658 : : * Recovery needs to be able to:
659 : : *
660 : : * record all revoke records, including the tid of the latest instance
661 : : * of each revoke in the journal
662 : : *
663 : : * check whether a given block in a given transaction should be replayed
664 : : * (ie. has not been revoked by a revoke record in that or a subsequent
665 : : * transaction)
666 : : *
667 : : * empty the revoke table after recovery.
668 : : */
669 : :
670 : : /*
671 : : * First, setting revoke records. We create a new revoke record for
672 : : * every block ever revoked in the log as we scan it for recovery, and
673 : : * we update the existing records if we find multiple revokes for a
674 : : * single block.
675 : : */
676 : :
677 : 1 : int jbd2_journal_set_revoke(journal_t *journal,
678 : : unsigned long long blocknr,
679 : : tid_t sequence)
680 : : {
681 : : struct jbd2_revoke_record_s *record;
682 : :
683 : 1 : record = find_revoke_record(journal, blocknr);
684 : 1 : if (record) {
685 : : /* If we have multiple occurrences, only record the
686 : : * latest sequence number in the hashed record */
687 : 1 : if (tid_gt(sequence, record->sequence))
688 : 1 : record->sequence = sequence;
689 : : return 0;
690 : : }
691 : 1 : return insert_revoke_hash(journal, blocknr, sequence);
692 : : }
693 : :
694 : : /*
695 : : * Test revoke records. For a given block referenced in the log, has
696 : : * that block been revoked? A revoke record with a given transaction
697 : : * sequence number revokes all blocks in that transaction and earlier
698 : : * ones, but later transactions still need replayed.
699 : : */
700 : :
701 : 1 : int jbd2_journal_test_revoke(journal_t *journal,
702 : : unsigned long long blocknr,
703 : : tid_t sequence)
704 : : {
705 : : struct jbd2_revoke_record_s *record;
706 : :
707 : 1 : record = find_revoke_record(journal, blocknr);
708 : 1 : if (!record)
709 : : return 0;
710 : 1 : if (tid_gt(sequence, record->sequence))
711 : : return 0;
712 : 1 : return 1;
713 : : }
714 : :
715 : : /*
716 : : * Finally, once recovery is over, we need to clear the revoke table so
717 : : * that it can be reused by the running filesystem.
718 : : */
719 : :
720 : 1 : void jbd2_journal_clear_revoke(journal_t *journal)
721 : : {
722 : : int i;
723 : : struct list_head *hash_list;
724 : : struct jbd2_revoke_record_s *record;
725 : : struct jbd2_revoke_table_s *revoke;
726 : :
727 : 1 : revoke = journal->j_revoke;
728 : :
729 : 1 : for (i = 0; i < revoke->hash_size; i++) {
730 : 1 : hash_list = &revoke->hash_table[i];
731 : 1 : while (!list_empty(hash_list)) {
732 : 1 : record = (struct jbd2_revoke_record_s*) hash_list->next;
733 : : list_del(&record->hash);
734 : 1 : kmem_cache_free(jbd2_revoke_record_cache, record);
735 : : }
736 : : }
737 : 1 : }
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