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 | return hash_64(val: block, bits: journal->j_revoke->hash_shift); |
134 | } |
135 | |
136 | 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 | record = kmem_cache_alloc(cachep: jbd2_revoke_record_cache, flags: gfp_mask); |
146 | if (!record) |
147 | return -ENOMEM; |
148 | |
149 | record->sequence = seq; |
150 | record->blocknr = blocknr; |
151 | hash_list = &journal->j_revoke->hash_table[hash(journal, block: blocknr)]; |
152 | spin_lock(lock: &journal->j_revoke_lock); |
153 | list_add(new: &record->hash, head: hash_list); |
154 | spin_unlock(lock: &journal->j_revoke_lock); |
155 | return 0; |
156 | } |
157 | |
158 | /* Find a revoke record in the journal's hash table. */ |
159 | |
160 | 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 | hash_list = &journal->j_revoke->hash_table[hash(journal, block: blocknr)]; |
167 | |
168 | spin_lock(lock: &journal->j_revoke_lock); |
169 | record = (struct jbd2_revoke_record_s *) hash_list->next; |
170 | while (&(record->hash) != hash_list) { |
171 | if (record->blocknr == blocknr) { |
172 | spin_unlock(lock: &journal->j_revoke_lock); |
173 | return record; |
174 | } |
175 | record = (struct jbd2_revoke_record_s *) record->hash.next; |
176 | } |
177 | spin_unlock(lock: &journal->j_revoke_lock); |
178 | return NULL; |
179 | } |
180 | |
181 | void jbd2_journal_destroy_revoke_record_cache(void) |
182 | { |
183 | kmem_cache_destroy(s: jbd2_revoke_record_cache); |
184 | jbd2_revoke_record_cache = NULL; |
185 | } |
186 | |
187 | void jbd2_journal_destroy_revoke_table_cache(void) |
188 | { |
189 | kmem_cache_destroy(s: jbd2_revoke_table_cache); |
190 | jbd2_revoke_table_cache = NULL; |
191 | } |
192 | |
193 | int __init jbd2_journal_init_revoke_record_cache(void) |
194 | { |
195 | J_ASSERT(!jbd2_revoke_record_cache); |
196 | jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s, |
197 | SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY); |
198 | |
199 | if (!jbd2_revoke_record_cache) { |
200 | pr_emerg("JBD2: failed to create revoke_record cache\n" ); |
201 | return -ENOMEM; |
202 | } |
203 | return 0; |
204 | } |
205 | |
206 | int __init jbd2_journal_init_revoke_table_cache(void) |
207 | { |
208 | J_ASSERT(!jbd2_revoke_table_cache); |
209 | jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s, |
210 | SLAB_TEMPORARY); |
211 | if (!jbd2_revoke_table_cache) { |
212 | pr_emerg("JBD2: failed to create revoke_table cache\n" ); |
213 | return -ENOMEM; |
214 | } |
215 | return 0; |
216 | } |
217 | |
218 | 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 | table = kmem_cache_alloc(cachep: jbd2_revoke_table_cache, GFP_KERNEL); |
225 | if (!table) |
226 | goto out; |
227 | |
228 | while((tmp >>= 1UL) != 0UL) |
229 | shift++; |
230 | |
231 | table->hash_size = hash_size; |
232 | table->hash_shift = shift; |
233 | table->hash_table = |
234 | kmalloc_array(n: hash_size, size: sizeof(struct list_head), GFP_KERNEL); |
235 | if (!table->hash_table) { |
236 | kmem_cache_free(s: jbd2_revoke_table_cache, objp: table); |
237 | table = NULL; |
238 | goto out; |
239 | } |
240 | |
241 | for (tmp = 0; tmp < hash_size; tmp++) |
242 | INIT_LIST_HEAD(list: &table->hash_table[tmp]); |
243 | |
244 | out: |
245 | return table; |
246 | } |
247 | |
248 | 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 | for (i = 0; i < table->hash_size; i++) { |
254 | hash_list = &table->hash_table[i]; |
255 | J_ASSERT(list_empty(hash_list)); |
256 | } |
257 | |
258 | kfree(objp: table->hash_table); |
259 | kmem_cache_free(s: jbd2_revoke_table_cache, objp: table); |
260 | } |
261 | |
262 | /* Initialise the revoke table for a given journal to a given size. */ |
263 | int jbd2_journal_init_revoke(journal_t *journal, int hash_size) |
264 | { |
265 | J_ASSERT(journal->j_revoke_table[0] == NULL); |
266 | J_ASSERT(is_power_of_2(hash_size)); |
267 | |
268 | journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size); |
269 | if (!journal->j_revoke_table[0]) |
270 | goto fail0; |
271 | |
272 | journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size); |
273 | if (!journal->j_revoke_table[1]) |
274 | goto fail1; |
275 | |
276 | journal->j_revoke = journal->j_revoke_table[1]; |
277 | |
278 | spin_lock_init(&journal->j_revoke_lock); |
279 | |
280 | return 0; |
281 | |
282 | fail1: |
283 | jbd2_journal_destroy_revoke_table(table: journal->j_revoke_table[0]); |
284 | 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 | void jbd2_journal_destroy_revoke(journal_t *journal) |
291 | { |
292 | journal->j_revoke = NULL; |
293 | if (journal->j_revoke_table[0]) |
294 | jbd2_journal_destroy_revoke_table(table: journal->j_revoke_table[0]); |
295 | if (journal->j_revoke_table[1]) |
296 | jbd2_journal_destroy_revoke_table(table: journal->j_revoke_table[1]); |
297 | } |
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 | 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 | might_sleep(); |
335 | if (bh_in) |
336 | BUFFER_TRACE(bh_in, "enter" ); |
337 | |
338 | journal = handle->h_transaction->t_journal; |
339 | if (!jbd2_journal_set_features(journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)){ |
340 | J_ASSERT (!"Cannot set revoke feature!" ); |
341 | return -EINVAL; |
342 | } |
343 | |
344 | bdev = journal->j_fs_dev; |
345 | bh = bh_in; |
346 | |
347 | if (!bh) { |
348 | bh = __find_get_block(bdev, block: blocknr, size: 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, block: blocknr, size: journal->j_blocksize); |
359 | if (bh2) { |
360 | /* ... and it has RevokeValid status... */ |
361 | if (bh2 != bh && buffer_revokevalid(bh: 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(bh: bh2); |
370 | } |
371 | } |
372 | #endif |
373 | |
374 | if (WARN_ON_ONCE(handle->h_revoke_credits <= 0)) { |
375 | if (!bh_in) |
376 | brelse(bh); |
377 | 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 | if (bh) { |
383 | if (!J_EXPECT_BH(bh, !buffer_revoked(bh), |
384 | "inconsistent data on disk" )) { |
385 | if (!bh_in) |
386 | brelse(bh); |
387 | return -EIO; |
388 | } |
389 | set_buffer_revoked(bh); |
390 | set_buffer_revokevalid(bh); |
391 | if (bh_in) { |
392 | BUFFER_TRACE(bh_in, "call jbd2_journal_forget" ); |
393 | jbd2_journal_forget(handle, bh_in); |
394 | } else { |
395 | BUFFER_TRACE(bh, "call brelse" ); |
396 | __brelse(bh); |
397 | } |
398 | } |
399 | handle->h_revoke_credits--; |
400 | |
401 | jbd2_debug(2, "insert revoke for block %llu, bh_in=%p\n" ,blocknr, bh_in); |
402 | err = insert_revoke_hash(journal, blocknr, |
403 | seq: handle->h_transaction->t_tid); |
404 | BUFFER_TRACE(bh_in, "exit" ); |
405 | 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 | int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh) |
424 | { |
425 | struct jbd2_revoke_record_s *record; |
426 | journal_t *journal = handle->h_transaction->t_journal; |
427 | int need_cancel; |
428 | int did_revoke = 0; /* akpm: debug */ |
429 | struct buffer_head *bh = jh2bh(jh); |
430 | |
431 | 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 | if (test_set_buffer_revokevalid(bh)) { |
438 | need_cancel = test_clear_buffer_revoked(bh); |
439 | } else { |
440 | need_cancel = 1; |
441 | clear_buffer_revoked(bh); |
442 | } |
443 | |
444 | if (need_cancel) { |
445 | record = find_revoke_record(journal, blocknr: bh->b_blocknr); |
446 | if (record) { |
447 | jbd2_debug(4, "cancelled existing revoke on " |
448 | "blocknr %llu\n" , (unsigned long long)bh->b_blocknr); |
449 | spin_lock(lock: &journal->j_revoke_lock); |
450 | list_del(entry: &record->hash); |
451 | spin_unlock(lock: &journal->j_revoke_lock); |
452 | kmem_cache_free(s: jbd2_revoke_record_cache, objp: record); |
453 | 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, blocknr: 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 | if (need_cancel) { |
468 | struct buffer_head *bh2; |
469 | bh2 = __find_get_block(bdev: bh->b_bdev, block: bh->b_blocknr, size: bh->b_size); |
470 | if (bh2) { |
471 | if (bh2 != bh) |
472 | clear_buffer_revoked(bh: bh2); |
473 | __brelse(bh2); |
474 | } |
475 | } |
476 | 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 | void jbd2_clear_buffer_revoked_flags(journal_t *journal) |
485 | { |
486 | struct jbd2_revoke_table_s *revoke = journal->j_revoke; |
487 | int i = 0; |
488 | |
489 | for (i = 0; i < revoke->hash_size; i++) { |
490 | struct list_head *hash_list; |
491 | struct list_head *list_entry; |
492 | hash_list = &revoke->hash_table[i]; |
493 | |
494 | list_for_each(list_entry, hash_list) { |
495 | struct jbd2_revoke_record_s *record; |
496 | struct buffer_head *bh; |
497 | record = (struct jbd2_revoke_record_s *)list_entry; |
498 | bh = __find_get_block(bdev: journal->j_fs_dev, |
499 | block: record->blocknr, |
500 | size: journal->j_blocksize); |
501 | if (bh) { |
502 | clear_buffer_revoked(bh); |
503 | __brelse(bh); |
504 | } |
505 | } |
506 | } |
507 | } |
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 | void jbd2_journal_switch_revoke_table(journal_t *journal) |
514 | { |
515 | int i; |
516 | |
517 | if (journal->j_revoke == journal->j_revoke_table[0]) |
518 | journal->j_revoke = journal->j_revoke_table[1]; |
519 | else |
520 | journal->j_revoke = journal->j_revoke_table[0]; |
521 | |
522 | for (i = 0; i < journal->j_revoke->hash_size; i++) |
523 | INIT_LIST_HEAD(list: &journal->j_revoke->hash_table[i]); |
524 | } |
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 | void jbd2_journal_write_revoke_records(transaction_t *transaction, |
531 | struct list_head *log_bufs) |
532 | { |
533 | journal_t *journal = transaction->t_journal; |
534 | struct buffer_head *descriptor; |
535 | struct jbd2_revoke_record_s *record; |
536 | struct jbd2_revoke_table_s *revoke; |
537 | struct list_head *hash_list; |
538 | int i, offset, count; |
539 | |
540 | descriptor = NULL; |
541 | offset = 0; |
542 | count = 0; |
543 | |
544 | /* select revoke table for committing transaction */ |
545 | revoke = journal->j_revoke == journal->j_revoke_table[0] ? |
546 | journal->j_revoke_table[1] : journal->j_revoke_table[0]; |
547 | |
548 | for (i = 0; i < revoke->hash_size; i++) { |
549 | hash_list = &revoke->hash_table[i]; |
550 | |
551 | while (!list_empty(head: hash_list)) { |
552 | record = (struct jbd2_revoke_record_s *) |
553 | hash_list->next; |
554 | write_one_revoke_record(transaction, log_bufs, |
555 | &descriptor, &offset, record); |
556 | count++; |
557 | list_del(entry: &record->hash); |
558 | kmem_cache_free(s: jbd2_revoke_record_cache, objp: record); |
559 | } |
560 | } |
561 | if (descriptor) |
562 | flush_descriptor(journal, descriptor, offset); |
563 | jbd2_debug(1, "Wrote %d revoke records\n" , count); |
564 | } |
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(j: 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(head: log_bufs, bh: descriptor); |
618 | |
619 | offset = sizeof(jbd2_journal_revoke_header_t); |
620 | *descriptorp = descriptor; |
621 | } |
622 | |
623 | if (jbd2_has_feature_64bit(j: 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 | static void flush_descriptor(journal_t *journal, |
642 | struct buffer_head *descriptor, |
643 | int offset) |
644 | { |
645 | jbd2_journal_revoke_header_t *; |
646 | |
647 | if (is_journal_aborted(journal)) |
648 | return; |
649 | |
650 | header = (jbd2_journal_revoke_header_t *)descriptor->b_data; |
651 | header->r_count = cpu_to_be32(offset); |
652 | jbd2_descriptor_block_csum_set(journal, descriptor); |
653 | |
654 | set_buffer_jwrite(descriptor); |
655 | BUFFER_TRACE(descriptor, "write" ); |
656 | set_buffer_dirty(descriptor); |
657 | write_dirty_buffer(bh: 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 | int jbd2_journal_set_revoke(journal_t *journal, |
684 | unsigned long long blocknr, |
685 | tid_t sequence) |
686 | { |
687 | struct jbd2_revoke_record_s *record; |
688 | |
689 | record = find_revoke_record(journal, blocknr); |
690 | if (record) { |
691 | /* If we have multiple occurrences, only record the |
692 | * latest sequence number in the hashed record */ |
693 | if (tid_gt(x: sequence, y: record->sequence)) |
694 | record->sequence = sequence; |
695 | return 0; |
696 | } |
697 | return insert_revoke_hash(journal, blocknr, seq: 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 | int jbd2_journal_test_revoke(journal_t *journal, |
708 | unsigned long long blocknr, |
709 | tid_t sequence) |
710 | { |
711 | struct jbd2_revoke_record_s *record; |
712 | |
713 | record = find_revoke_record(journal, blocknr); |
714 | if (!record) |
715 | return 0; |
716 | if (tid_gt(x: sequence, y: record->sequence)) |
717 | 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 | void jbd2_journal_clear_revoke(journal_t *journal) |
727 | { |
728 | int i; |
729 | struct list_head *hash_list; |
730 | struct jbd2_revoke_record_s *record; |
731 | struct jbd2_revoke_table_s *revoke; |
732 | |
733 | revoke = journal->j_revoke; |
734 | |
735 | for (i = 0; i < revoke->hash_size; i++) { |
736 | hash_list = &revoke->hash_table[i]; |
737 | while (!list_empty(head: hash_list)) { |
738 | record = (struct jbd2_revoke_record_s*) hash_list->next; |
739 | list_del(entry: &record->hash); |
740 | kmem_cache_free(s: jbd2_revoke_record_cache, objp: record); |
741 | } |
742 | } |
743 | } |
744 | |