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 * Revoke information on buffers is a tri-state value: 51 * 52 * RevokeValid clear: no cached revoke status, need to look it up 53 * RevokeValid set, Revoked clear: 54 * buffer has not been revoked, and cancel_revoke 55 * need do nothing. 56 * RevokeValid set, Revoked set: 57 * buffer has been revoked. 58 * 59 * Locking rules: 60 * We keep two hash tables of revoke records. One hashtable belongs to the 61 * running transaction (is pointed to by journal->j_revoke), the other one 62 * belongs to the committing transaction. Accesses to the second hash table 63 * happen only from the kjournald and no other thread touches this table. Also 64 * journal_switch_revoke_table() which switches which hashtable belongs to the 65 * running and which to the committing transaction is called only from 66 * kjournald. Therefore we need no locks when accessing the hashtable belonging 67 * to the committing transaction. 68 * 69 * All users operating on the hash table belonging to the running transaction 70 * have a handle to the transaction. Therefore they are safe from kjournald 71 * switching hash tables under them. For operations on the lists of entries in 72 * the hash table j_revoke_lock is used. 73 * 74 * Finally, also replay code uses the hash tables but at this moment noone else 75 * can touch them (filesystem isn't mounted yet) and hence no locking is 76 * needed. 77 */ 78 79 #ifndef __KERNEL__ 80 #include "jfs_user.h" 81 #else 82 #include <linux/time.h> 83 #include <linux/fs.h> 84 #include <linux/jbd2.h> 85 #include <linux/errno.h> 86 #include <linux/slab.h> 87 #include <linux/list.h> 88 #include <linux/init.h> 89 #include <linux/bio.h> 90 #endif 91 #include <linux/log2.h> 92 93 static struct kmem_cache *jbd2_revoke_record_cache; 94 static struct kmem_cache *jbd2_revoke_table_cache; 95 96 /* Each revoke record represents one single revoked block. During 97 journal replay, this involves recording the transaction ID of the 98 last transaction to revoke this block. */ 99 100 struct jbd2_revoke_record_s 101 { 102 struct list_head hash; 103 tid_t sequence; /* Used for recovery only */ 104 unsigned long long blocknr; 105 }; 106 107 108 /* The revoke table is just a simple hash table of revoke records. */ 109 struct jbd2_revoke_table_s 110 { 111 /* It is conceivable that we might want a larger hash table 112 * for recovery. Must be a power of two. */ 113 int hash_size; 114 int hash_shift; 115 struct list_head *hash_table; 116 }; 117 118 119 #ifdef __KERNEL__ 120 static void write_one_revoke_record(journal_t *, transaction_t *, 121 struct journal_head **, int *, 122 struct jbd2_revoke_record_s *, int); 123 static void flush_descriptor(journal_t *, struct journal_head *, int, int); 124 #endif 125 126 /* Utility functions to maintain the revoke table */ 127 128 /* Borrowed from buffer.c: this is a tried and tested block hash function */ 129 static inline int hash(journal_t *journal, unsigned long long block) 130 { 131 struct jbd2_revoke_table_s *table = journal->j_revoke; 132 int hash_shift = table->hash_shift; 133 int hash = (int)block ^ (int)((block >> 31) >> 1); 134 135 return ((hash << (hash_shift - 6)) ^ 136 (hash >> 13) ^ 137 (hash << (hash_shift - 12))) & (table->hash_size - 1); 138 } 139 140 static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr, 141 tid_t seq) 142 { 143 struct list_head *hash_list; 144 struct jbd2_revoke_record_s *record; 145 146 repeat: 147 record = kmem_cache_alloc(jbd2_revoke_record_cache, GFP_NOFS); 148 if (!record) 149 goto oom; 150 151 record->sequence = seq; 152 record->blocknr = blocknr; 153 hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; 154 spin_lock(&journal->j_revoke_lock); 155 list_add(&record->hash, hash_list); 156 spin_unlock(&journal->j_revoke_lock); 157 return 0; 158 159 oom: 160 if (!journal_oom_retry) 161 return -ENOMEM; 162 jbd_debug(1, "ENOMEM in %s, retrying\n", __func__); 163 yield(); 164 goto repeat; 165 } 166 167 /* Find a revoke record in the journal's hash table. */ 168 169 static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal, 170 unsigned long long blocknr) 171 { 172 struct list_head *hash_list; 173 struct jbd2_revoke_record_s *record; 174 175 hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; 176 177 spin_lock(&journal->j_revoke_lock); 178 record = (struct jbd2_revoke_record_s *) hash_list->next; 179 while (&(record->hash) != hash_list) { 180 if (record->blocknr == blocknr) { 181 spin_unlock(&journal->j_revoke_lock); 182 return record; 183 } 184 record = (struct jbd2_revoke_record_s *) record->hash.next; 185 } 186 spin_unlock(&journal->j_revoke_lock); 187 return NULL; 188 } 189 190 void jbd2_journal_destroy_revoke_caches(void) 191 { 192 if (jbd2_revoke_record_cache) { 193 kmem_cache_destroy(jbd2_revoke_record_cache); 194 jbd2_revoke_record_cache = NULL; 195 } 196 if (jbd2_revoke_table_cache) { 197 kmem_cache_destroy(jbd2_revoke_table_cache); 198 jbd2_revoke_table_cache = NULL; 199 } 200 } 201 202 int __init jbd2_journal_init_revoke_caches(void) 203 { 204 J_ASSERT(!jbd2_revoke_record_cache); 205 J_ASSERT(!jbd2_revoke_table_cache); 206 207 jbd2_revoke_record_cache = kmem_cache_create("jbd2_revoke_record", 208 sizeof(struct jbd2_revoke_record_s), 209 0, 210 SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY, 211 NULL); 212 if (!jbd2_revoke_record_cache) 213 goto record_cache_failure; 214 215 jbd2_revoke_table_cache = kmem_cache_create("jbd2_revoke_table", 216 sizeof(struct jbd2_revoke_table_s), 217 0, SLAB_TEMPORARY, NULL); 218 if (!jbd2_revoke_table_cache) 219 goto table_cache_failure; 220 return 0; 221 table_cache_failure: 222 jbd2_journal_destroy_revoke_caches(); 223 record_cache_failure: 224 return -ENOMEM; 225 } 226 227 static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size) 228 { 229 int shift = 0; 230 int tmp = hash_size; 231 struct jbd2_revoke_table_s *table; 232 233 table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL); 234 if (!table) 235 goto out; 236 237 while((tmp >>= 1UL) != 0UL) 238 shift++; 239 240 table->hash_size = hash_size; 241 table->hash_shift = shift; 242 table->hash_table = 243 kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); 244 if (!table->hash_table) { 245 kmem_cache_free(jbd2_revoke_table_cache, table); 246 table = NULL; 247 goto out; 248 } 249 250 for (tmp = 0; tmp < hash_size; tmp++) 251 INIT_LIST_HEAD(&table->hash_table[tmp]); 252 253 out: 254 return table; 255 } 256 257 static void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table) 258 { 259 int i; 260 struct list_head *hash_list; 261 262 for (i = 0; i < table->hash_size; i++) { 263 hash_list = &table->hash_table[i]; 264 J_ASSERT(list_empty(hash_list)); 265 } 266 267 kfree(table->hash_table); 268 kmem_cache_free(jbd2_revoke_table_cache, table); 269 } 270 271 /* Initialise the revoke table for a given journal to a given size. */ 272 int jbd2_journal_init_revoke(journal_t *journal, int hash_size) 273 { 274 J_ASSERT(journal->j_revoke_table[0] == NULL); 275 J_ASSERT(is_power_of_2(hash_size)); 276 277 journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size); 278 if (!journal->j_revoke_table[0]) 279 goto fail0; 280 281 journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size); 282 if (!journal->j_revoke_table[1]) 283 goto fail1; 284 285 journal->j_revoke = journal->j_revoke_table[1]; 286 287 spin_lock_init(&journal->j_revoke_lock); 288 289 return 0; 290 291 fail1: 292 jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]); 293 fail0: 294 return -ENOMEM; 295 } 296 297 /* Destroy a journal's revoke table. The table must already be empty! */ 298 void jbd2_journal_destroy_revoke(journal_t *journal) 299 { 300 journal->j_revoke = NULL; 301 if (journal->j_revoke_table[0]) 302 jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]); 303 if (journal->j_revoke_table[1]) 304 jbd2_journal_destroy_revoke_table(journal->j_revoke_table[1]); 305 } 306 307 308 #ifdef __KERNEL__ 309 310 /* 311 * jbd2_journal_revoke: revoke a given buffer_head from the journal. This 312 * prevents the block from being replayed during recovery if we take a 313 * crash after this current transaction commits. Any subsequent 314 * metadata writes of the buffer in this transaction cancel the 315 * revoke. 316 * 317 * Note that this call may block --- it is up to the caller to make 318 * sure that there are no further calls to journal_write_metadata 319 * before the revoke is complete. In ext3, this implies calling the 320 * revoke before clearing the block bitmap when we are deleting 321 * metadata. 322 * 323 * Revoke performs a jbd2_journal_forget on any buffer_head passed in as a 324 * parameter, but does _not_ forget the buffer_head if the bh was only 325 * found implicitly. 326 * 327 * bh_in may not be a journalled buffer - it may have come off 328 * the hash tables without an attached journal_head. 329 * 330 * If bh_in is non-zero, jbd2_journal_revoke() will decrement its b_count 331 * by one. 332 */ 333 334 int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr, 335 struct buffer_head *bh_in) 336 { 337 struct buffer_head *bh = NULL; 338 journal_t *journal; 339 struct block_device *bdev; 340 int err; 341 342 might_sleep(); 343 if (bh_in) 344 BUFFER_TRACE(bh_in, "enter"); 345 346 journal = handle->h_transaction->t_journal; 347 if (!jbd2_journal_set_features(journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)){ 348 J_ASSERT (!"Cannot set revoke feature!"); 349 return -EINVAL; 350 } 351 352 bdev = journal->j_fs_dev; 353 bh = bh_in; 354 355 if (!bh) { 356 bh = __find_get_block(bdev, blocknr, journal->j_blocksize); 357 if (bh) 358 BUFFER_TRACE(bh, "found on hash"); 359 } 360 #ifdef JBD2_EXPENSIVE_CHECKING 361 else { 362 struct buffer_head *bh2; 363 364 /* If there is a different buffer_head lying around in 365 * memory anywhere... */ 366 bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize); 367 if (bh2) { 368 /* ... and it has RevokeValid status... */ 369 if (bh2 != bh && buffer_revokevalid(bh2)) 370 /* ...then it better be revoked too, 371 * since it's illegal to create a revoke 372 * record against a buffer_head which is 373 * not marked revoked --- that would 374 * risk missing a subsequent revoke 375 * cancel. */ 376 J_ASSERT_BH(bh2, buffer_revoked(bh2)); 377 put_bh(bh2); 378 } 379 } 380 #endif 381 382 /* We really ought not ever to revoke twice in a row without 383 first having the revoke cancelled: it's illegal to free a 384 block twice without allocating it in between! */ 385 if (bh) { 386 if (!J_EXPECT_BH(bh, !buffer_revoked(bh), 387 "inconsistent data on disk")) { 388 if (!bh_in) 389 brelse(bh); 390 return -EIO; 391 } 392 set_buffer_revoked(bh); 393 set_buffer_revokevalid(bh); 394 if (bh_in) { 395 BUFFER_TRACE(bh_in, "call jbd2_journal_forget"); 396 jbd2_journal_forget(handle, bh_in); 397 } else { 398 BUFFER_TRACE(bh, "call brelse"); 399 __brelse(bh); 400 } 401 } 402 403 jbd_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in); 404 err = insert_revoke_hash(journal, blocknr, 405 handle->h_transaction->t_tid); 406 BUFFER_TRACE(bh_in, "exit"); 407 return err; 408 } 409 410 /* 411 * Cancel an outstanding revoke. For use only internally by the 412 * journaling code (called from jbd2_journal_get_write_access). 413 * 414 * We trust buffer_revoked() on the buffer if the buffer is already 415 * being journaled: if there is no revoke pending on the buffer, then we 416 * don't do anything here. 417 * 418 * This would break if it were possible for a buffer to be revoked and 419 * discarded, and then reallocated within the same transaction. In such 420 * a case we would have lost the revoked bit, but when we arrived here 421 * the second time we would still have a pending revoke to cancel. So, 422 * do not trust the Revoked bit on buffers unless RevokeValid is also 423 * set. 424 */ 425 int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh) 426 { 427 struct jbd2_revoke_record_s *record; 428 journal_t *journal = handle->h_transaction->t_journal; 429 int need_cancel; 430 int did_revoke = 0; /* akpm: debug */ 431 struct buffer_head *bh = jh2bh(jh); 432 433 jbd_debug(4, "journal_head %p, cancelling revoke\n", jh); 434 435 /* Is the existing Revoke bit valid? If so, we trust it, and 436 * only perform the full cancel if the revoke bit is set. If 437 * not, we can't trust the revoke bit, and we need to do the 438 * full search for a revoke record. */ 439 if (test_set_buffer_revokevalid(bh)) { 440 need_cancel = test_clear_buffer_revoked(bh); 441 } else { 442 need_cancel = 1; 443 clear_buffer_revoked(bh); 444 } 445 446 if (need_cancel) { 447 record = find_revoke_record(journal, bh->b_blocknr); 448 if (record) { 449 jbd_debug(4, "cancelled existing revoke on " 450 "blocknr %llu\n", (unsigned long long)bh->b_blocknr); 451 spin_lock(&journal->j_revoke_lock); 452 list_del(&record->hash); 453 spin_unlock(&journal->j_revoke_lock); 454 kmem_cache_free(jbd2_revoke_record_cache, record); 455 did_revoke = 1; 456 } 457 } 458 459 #ifdef JBD2_EXPENSIVE_CHECKING 460 /* There better not be one left behind by now! */ 461 record = find_revoke_record(journal, bh->b_blocknr); 462 J_ASSERT_JH(jh, record == NULL); 463 #endif 464 465 /* Finally, have we just cleared revoke on an unhashed 466 * buffer_head? If so, we'd better make sure we clear the 467 * revoked status on any hashed alias too, otherwise the revoke 468 * state machine will get very upset later on. */ 469 if (need_cancel) { 470 struct buffer_head *bh2; 471 bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size); 472 if (bh2) { 473 if (bh2 != bh) 474 clear_buffer_revoked(bh2); 475 __brelse(bh2); 476 } 477 } 478 return did_revoke; 479 } 480 481 /* journal_switch_revoke table select j_revoke for next transaction 482 * we do not want to suspend any processing until all revokes are 483 * written -bzzz 484 */ 485 void jbd2_journal_switch_revoke_table(journal_t *journal) 486 { 487 int i; 488 489 if (journal->j_revoke == journal->j_revoke_table[0]) 490 journal->j_revoke = journal->j_revoke_table[1]; 491 else 492 journal->j_revoke = journal->j_revoke_table[0]; 493 494 for (i = 0; i < journal->j_revoke->hash_size; i++) 495 INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]); 496 } 497 498 /* 499 * Write revoke records to the journal for all entries in the current 500 * revoke hash, deleting the entries as we go. 501 */ 502 void jbd2_journal_write_revoke_records(journal_t *journal, 503 transaction_t *transaction, 504 int write_op) 505 { 506 struct journal_head *descriptor; 507 struct jbd2_revoke_record_s *record; 508 struct jbd2_revoke_table_s *revoke; 509 struct list_head *hash_list; 510 int i, offset, count; 511 512 descriptor = NULL; 513 offset = 0; 514 count = 0; 515 516 /* select revoke table for committing transaction */ 517 revoke = journal->j_revoke == journal->j_revoke_table[0] ? 518 journal->j_revoke_table[1] : journal->j_revoke_table[0]; 519 520 for (i = 0; i < revoke->hash_size; i++) { 521 hash_list = &revoke->hash_table[i]; 522 523 while (!list_empty(hash_list)) { 524 record = (struct jbd2_revoke_record_s *) 525 hash_list->next; 526 write_one_revoke_record(journal, transaction, 527 &descriptor, &offset, 528 record, write_op); 529 count++; 530 list_del(&record->hash); 531 kmem_cache_free(jbd2_revoke_record_cache, record); 532 } 533 } 534 if (descriptor) 535 flush_descriptor(journal, descriptor, offset, write_op); 536 jbd_debug(1, "Wrote %d revoke records\n", count); 537 } 538 539 /* 540 * Write out one revoke record. We need to create a new descriptor 541 * block if the old one is full or if we have not already created one. 542 */ 543 544 static void write_one_revoke_record(journal_t *journal, 545 transaction_t *transaction, 546 struct journal_head **descriptorp, 547 int *offsetp, 548 struct jbd2_revoke_record_s *record, 549 int write_op) 550 { 551 struct journal_head *descriptor; 552 int offset; 553 journal_header_t *header; 554 555 /* If we are already aborting, this all becomes a noop. We 556 still need to go round the loop in 557 jbd2_journal_write_revoke_records in order to free all of the 558 revoke records: only the IO to the journal is omitted. */ 559 if (is_journal_aborted(journal)) 560 return; 561 562 descriptor = *descriptorp; 563 offset = *offsetp; 564 565 /* Make sure we have a descriptor with space left for the record */ 566 if (descriptor) { 567 if (offset == journal->j_blocksize) { 568 flush_descriptor(journal, descriptor, offset, write_op); 569 descriptor = NULL; 570 } 571 } 572 573 if (!descriptor) { 574 descriptor = jbd2_journal_get_descriptor_buffer(journal); 575 if (!descriptor) 576 return; 577 header = (journal_header_t *) &jh2bh(descriptor)->b_data[0]; 578 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 579 header->h_blocktype = cpu_to_be32(JBD2_REVOKE_BLOCK); 580 header->h_sequence = cpu_to_be32(transaction->t_tid); 581 582 /* Record it so that we can wait for IO completion later */ 583 JBUFFER_TRACE(descriptor, "file as BJ_LogCtl"); 584 jbd2_journal_file_buffer(descriptor, transaction, BJ_LogCtl); 585 586 offset = sizeof(jbd2_journal_revoke_header_t); 587 *descriptorp = descriptor; 588 } 589 590 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) { 591 * ((__be64 *)(&jh2bh(descriptor)->b_data[offset])) = 592 cpu_to_be64(record->blocknr); 593 offset += 8; 594 595 } else { 596 * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) = 597 cpu_to_be32(record->blocknr); 598 offset += 4; 599 } 600 601 *offsetp = offset; 602 } 603 604 /* 605 * Flush a revoke descriptor out to the journal. If we are aborting, 606 * this is a noop; otherwise we are generating a buffer which needs to 607 * be waited for during commit, so it has to go onto the appropriate 608 * journal buffer list. 609 */ 610 611 static void flush_descriptor(journal_t *journal, 612 struct journal_head *descriptor, 613 int offset, int write_op) 614 { 615 jbd2_journal_revoke_header_t *header; 616 struct buffer_head *bh = jh2bh(descriptor); 617 618 if (is_journal_aborted(journal)) { 619 put_bh(bh); 620 return; 621 } 622 623 header = (jbd2_journal_revoke_header_t *) jh2bh(descriptor)->b_data; 624 header->r_count = cpu_to_be32(offset); 625 set_buffer_jwrite(bh); 626 BUFFER_TRACE(bh, "write"); 627 set_buffer_dirty(bh); 628 write_dirty_buffer(bh, write_op); 629 } 630 #endif 631 632 /* 633 * Revoke support for recovery. 634 * 635 * Recovery needs to be able to: 636 * 637 * record all revoke records, including the tid of the latest instance 638 * of each revoke in the journal 639 * 640 * check whether a given block in a given transaction should be replayed 641 * (ie. has not been revoked by a revoke record in that or a subsequent 642 * transaction) 643 * 644 * empty the revoke table after recovery. 645 */ 646 647 /* 648 * First, setting revoke records. We create a new revoke record for 649 * every block ever revoked in the log as we scan it for recovery, and 650 * we update the existing records if we find multiple revokes for a 651 * single block. 652 */ 653 654 int jbd2_journal_set_revoke(journal_t *journal, 655 unsigned long long blocknr, 656 tid_t sequence) 657 { 658 struct jbd2_revoke_record_s *record; 659 660 record = find_revoke_record(journal, blocknr); 661 if (record) { 662 /* If we have multiple occurrences, only record the 663 * latest sequence number in the hashed record */ 664 if (tid_gt(sequence, record->sequence)) 665 record->sequence = sequence; 666 return 0; 667 } 668 return insert_revoke_hash(journal, blocknr, sequence); 669 } 670 671 /* 672 * Test revoke records. For a given block referenced in the log, has 673 * that block been revoked? A revoke record with a given transaction 674 * sequence number revokes all blocks in that transaction and earlier 675 * ones, but later transactions still need replayed. 676 */ 677 678 int jbd2_journal_test_revoke(journal_t *journal, 679 unsigned long long blocknr, 680 tid_t sequence) 681 { 682 struct jbd2_revoke_record_s *record; 683 684 record = find_revoke_record(journal, blocknr); 685 if (!record) 686 return 0; 687 if (tid_gt(sequence, record->sequence)) 688 return 0; 689 return 1; 690 } 691 692 /* 693 * Finally, once recovery is over, we need to clear the revoke table so 694 * that it can be reused by the running filesystem. 695 */ 696 697 void jbd2_journal_clear_revoke(journal_t *journal) 698 { 699 int i; 700 struct list_head *hash_list; 701 struct jbd2_revoke_record_s *record; 702 struct jbd2_revoke_table_s *revoke; 703 704 revoke = journal->j_revoke; 705 706 for (i = 0; i < revoke->hash_size; i++) { 707 hash_list = &revoke->hash_table[i]; 708 while (!list_empty(hash_list)) { 709 record = (struct jbd2_revoke_record_s*) hash_list->next; 710 list_del(&record->hash); 711 kmem_cache_free(jbd2_revoke_record_cache, record); 712 } 713 } 714 } 715