1/* 2 * linux/fs/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RevokeValid clear: no cached revoke status, need to look it up 53 * RevokeValid set, Revoked clear: 54 * buffer has not been revoked, and cancel_revoke 55 * need do nothing. 56 * RevokeValid set, Revoked set: 57 * buffer has been revoked. 58 */ 59 60#include <linux/time.h> 61#include <linux/fs.h> 62#include <linux/errno.h> 63#include <linux/slab.h> 64#include <linux/list.h> 65#include <linux/smp_lock.h> 66#include <linux/init.h> 67#include "hfsplus_jbd.h" 68 69static kmem_cache_t *hfsplus_revoke_record_cache; 70static kmem_cache_t *hfsplus_revoke_table_cache; 71 72/* Each revoke record represents one single revoked block. During 73 journal replay, this involves recording the transaction ID of the 74 last transaction to revoke this block. */ 75 76struct hfsplus_jbd_revoke_record_s 77{ 78 struct list_head hash; 79 hfsplus_jbd_tid_t sequence; /* Used for recovery only */ 80 unsigned long blocknr; 81}; 82 83 84/* The revoke table is just a simple hash table of revoke records. */ 85struct hfsplus_jbd_revoke_table_s 86{ 87 /* It is conceivable that we might want a larger hash table 88 * for recovery. Must be a power of two. */ 89 int hash_size; 90 int hash_shift; 91 struct list_head *hash_table; 92}; 93 94 95#ifdef __KERNEL__ 96static void write_one_revoke_record(hfsplus_jbd_t *, hfsplus_transaction_t *, 97 struct hfsplus_jbd_head **, int *, 98 struct hfsplus_jbd_revoke_record_s *); 99static void flush_descriptor(hfsplus_jbd_t *, struct hfsplus_jbd_head *, int); 100#endif 101 102/* Utility functions to maintain the revoke table */ 103 104/* Borrowed from buffer.c: this is a tried and tested block hash function */ 105static inline int hash(hfsplus_jbd_t *journal, unsigned long block) 106{ 107 struct hfsplus_jbd_revoke_table_s *table = journal->j_revoke; 108 int hash_shift = table->hash_shift; 109 110 return ((block << (hash_shift - 6)) ^ 111 (block >> 13) ^ 112 (block << (hash_shift - 12))) & (table->hash_size - 1); 113} 114 115static int insert_revoke_hash(hfsplus_jbd_t *journal, unsigned long blocknr, 116 hfsplus_jbd_tid_t seq) 117{ 118 struct list_head *hash_list; 119 struct hfsplus_jbd_revoke_record_s *record; 120 121repeat: 122 record = kmem_cache_alloc(hfsplus_revoke_record_cache, GFP_NOFS); 123 if (!record) 124 goto oom; 125 126 record->sequence = seq; 127 record->blocknr = blocknr; 128 hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; 129 spin_lock(&journal->j_revoke_lock); 130 list_add(&record->hash, hash_list); 131 spin_unlock(&journal->j_revoke_lock); 132 return 0; 133 134oom: 135 if (!hfsplus_jbd_oom_retry) 136 return -ENOMEM; 137 hfsplus_jbd_debug(1, "ENOMEM in %s, retrying\n", __FUNCTION__); 138 yield(); 139 goto repeat; 140} 141 142/* Find a revoke record in the journal's hash table. */ 143 144static struct hfsplus_jbd_revoke_record_s *find_revoke_record(hfsplus_jbd_t *journal, 145 unsigned long blocknr) 146{ 147 struct list_head *hash_list; 148 struct hfsplus_jbd_revoke_record_s *record; 149 150 hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)]; 151 152 spin_lock(&journal->j_revoke_lock); 153 record = (struct hfsplus_jbd_revoke_record_s *) hash_list->next; 154 while (&(record->hash) != hash_list) { 155 if (record->blocknr == blocknr) { 156 spin_unlock(&journal->j_revoke_lock); 157 return record; 158 } 159 record = (struct hfsplus_jbd_revoke_record_s *) record->hash.next; 160 } 161 spin_unlock(&journal->j_revoke_lock); 162 return NULL; 163} 164 165int __init hfsplus_jbd_init_revoke_caches(void) 166{ 167 hfsplus_revoke_record_cache = kmem_cache_create("hfsplus_jbd_revoke_record", 168 sizeof(struct hfsplus_jbd_revoke_record_s), 169 0, SLAB_HWCACHE_ALIGN, NULL, NULL); 170 if (hfsplus_revoke_record_cache == 0) 171 return -ENOMEM; 172 173 hfsplus_revoke_table_cache = kmem_cache_create("hfsplus_jbd_revoke_table", 174 sizeof(struct hfsplus_jbd_revoke_table_s), 175 0, 0, NULL, NULL); 176 if (hfsplus_revoke_table_cache == 0) { 177 kmem_cache_destroy(hfsplus_revoke_record_cache); 178 hfsplus_revoke_record_cache = NULL; 179 return -ENOMEM; 180 } 181 return 0; 182} 183 184void hfsplus_jbd_destroy_revoke_caches(void) 185{ 186 kmem_cache_destroy(hfsplus_revoke_record_cache); 187 hfsplus_revoke_record_cache = NULL; 188 kmem_cache_destroy(hfsplus_revoke_table_cache); 189 hfsplus_revoke_table_cache = NULL; 190} 191 192/* Initialise the revoke table for a given journal to a given size. */ 193 194int hfsplus_jbd_init_revoke(hfsplus_jbd_t *journal, int hash_size) 195{ 196 int shift, tmp; 197 198 HFSPLUS_J_ASSERT (journal->j_revoke_table[0] == NULL); 199 200 shift = 0; 201 tmp = hash_size; 202 while((tmp >>= 1UL) != 0UL) 203 shift++; 204 205 journal->j_revoke_table[0] = kmem_cache_alloc(hfsplus_revoke_table_cache, GFP_KERNEL); 206 if (!journal->j_revoke_table[0]) 207 return -ENOMEM; 208 journal->j_revoke = journal->j_revoke_table[0]; 209 210 /* Check that the hash_size is a power of two */ 211 HFSPLUS_J_ASSERT ((hash_size & (hash_size-1)) == 0); 212 213 journal->j_revoke->hash_size = hash_size; 214 215 journal->j_revoke->hash_shift = shift; 216 217 journal->j_revoke->hash_table = 218 kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); 219 if (!journal->j_revoke->hash_table) { 220 kmem_cache_free(hfsplus_revoke_table_cache, journal->j_revoke_table[0]); 221 journal->j_revoke = NULL; 222 return -ENOMEM; 223 } 224 225 for (tmp = 0; tmp < hash_size; tmp++) 226 INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]); 227 228 journal->j_revoke_table[1] = kmem_cache_alloc(hfsplus_revoke_table_cache, GFP_KERNEL); 229 if (!journal->j_revoke_table[1]) { 230 kfree(journal->j_revoke_table[0]->hash_table); 231 kmem_cache_free(hfsplus_revoke_table_cache, journal->j_revoke_table[0]); 232 return -ENOMEM; 233 } 234 235 journal->j_revoke = journal->j_revoke_table[1]; 236 237 /* Check that the hash_size is a power of two */ 238 HFSPLUS_J_ASSERT ((hash_size & (hash_size-1)) == 0); 239 240 journal->j_revoke->hash_size = hash_size; 241 242 journal->j_revoke->hash_shift = shift; 243 244 journal->j_revoke->hash_table = 245 kmalloc(hash_size * sizeof(struct list_head), GFP_KERNEL); 246 if (!journal->j_revoke->hash_table) { 247 kfree(journal->j_revoke_table[0]->hash_table); 248 kmem_cache_free(hfsplus_revoke_table_cache, journal->j_revoke_table[0]); 249 kmem_cache_free(hfsplus_revoke_table_cache, journal->j_revoke_table[1]); 250 journal->j_revoke = NULL; 251 return -ENOMEM; 252 } 253 254 for (tmp = 0; tmp < hash_size; tmp++) 255 INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]); 256 257 spin_lock_init(&journal->j_revoke_lock); 258 259 return 0; 260} 261 262/* Destoy a journal's revoke table. The table must already be empty! */ 263 264void hfsplus_jbd_destroy_revoke(hfsplus_jbd_t *journal) 265{ 266 struct hfsplus_jbd_revoke_table_s *table; 267 struct list_head *hash_list; 268 int i; 269 270 table = journal->j_revoke_table[0]; 271 if (!table) 272 return; 273 274 for (i=0; i<table->hash_size; i++) { 275 hash_list = &table->hash_table[i]; 276 HFSPLUS_J_ASSERT (list_empty(hash_list)); 277 } 278 279 kfree(table->hash_table); 280 kmem_cache_free(hfsplus_revoke_table_cache, table); 281 journal->j_revoke = NULL; 282 283 table = journal->j_revoke_table[1]; 284 if (!table) 285 return; 286 287 for (i=0; i<table->hash_size; i++) { 288 hash_list = &table->hash_table[i]; 289 HFSPLUS_J_ASSERT (list_empty(hash_list)); 290 } 291 292 kfree(table->hash_table); 293 kmem_cache_free(hfsplus_revoke_table_cache, table); 294 journal->j_revoke = NULL; 295} 296 297 298#ifdef __KERNEL__ 299 300/* 301 * hfsplus_jbd_revoke: revoke a given buffer_head from the journal. This 302 * prevents the block from being replayed during recovery if we take a 303 * crash after this current transaction commits. Any subsequent 304 * metadata writes of the buffer in this transaction cancel the 305 * revoke. 306 * 307 * Note that this call may block --- it is up to the caller to make 308 * sure that there are no further calls to hfsplus_jbd_write_metadata 309 * before the revoke is complete. In ext3, this implies calling the 310 * revoke before clearing the block bitmap when we are deleting 311 * metadata. 312 * 313 * Revoke performs a hfsplus_jbd_forget on any buffer_head passed in as a 314 * parameter, but does _not_ forget the buffer_head if the bh was only 315 * found implicitly. 316 * 317 * bh_in may not be a journalled buffer - it may have come off 318 * the hash tables without an attached hfsplus_jbd_head. 319 * 320 * If bh_in is non-zero, hfsplus_jbd_revoke() will decrement its b_count 321 * by one. 322 */ 323 324int hfsplus_jbd_revoke(hfsplus_jbd_handle_t *handle, unsigned long blocknr, 325 struct buffer_head *bh_in) 326{ 327 struct buffer_head *bh = NULL; 328 hfsplus_jbd_t *journal; 329 struct block_device *bdev; 330 int err; 331 332 might_sleep(); 333 if (bh_in) 334 HFSPLUS_BUFFER_TRACE(bh_in, "enter"); 335 336 journal = handle->h_transaction->t_journal; 337 if (!hfsplus_jbd_set_features(journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)){ 338 HFSPLUS_J_ASSERT (!"Cannot set revoke feature!"); 339 return -EINVAL; 340 } 341 342 bdev = journal->j_fs_dev; 343 bh = bh_in; 344 345 if (!bh) { 346 bh = __find_get_block(bdev, blocknr, journal->j_blocksize); 347 if (bh) 348 HFSPLUS_BUFFER_TRACE(bh, "found on hash"); 349 } 350#ifdef JBD_EXPENSIVE_CHECKING 351 else { 352 struct buffer_head *bh2; 353 354 /* If there is a different buffer_head lying around in 355 * memory anywhere... */ 356 bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize); 357 if (bh2) { 358 /* ... and it has RevokeValid status... */ 359 if (bh2 != bh && buffer_revokevalid(bh2)) 360 /* ...then it better be revoked too, 361 * since it's illegal to create a revoke 362 * record against a buffer_head which is 363 * not marked revoked --- that would 364 * risk missing a subsequent revoke 365 * cancel. */ 366 HFSPLUS_J_ASSERT_BH(bh2, buffer_hfsplus_jbd_revoked(bh2)); 367 put_bh(bh2); 368 } 369 } 370#endif 371 372 /* We really ought not ever to revoke twice in a row without 373 first having the revoke cancelled: it's illegal to free a 374 block twice without allocating it in between! */ 375 if (bh) { 376 if (!HFSPLUS_J_EXPECT_BH(bh, !buffer_hfsplus_jbd_revoked(bh), 377 "inconsistent data on disk")) { 378 if (!bh_in) 379 brelse(bh); 380 return -EIO; 381 } 382 set_buffer_hfsplus_jbd_revoked(bh); 383 set_buffer_hfsplus_jbd_revokevalid(bh); 384 if (bh_in) { 385 HFSPLUS_BUFFER_TRACE(bh_in, "call hfsplus_jbd_forget"); 386 hfsplus_jbd_forget(handle, bh_in); 387 } else { 388 HFSPLUS_BUFFER_TRACE(bh, "call brelse"); 389 __brelse(bh); 390 } 391 } 392 393 hfsplus_jbd_debug(2, "insert revoke for block %lu, bh_in=%p\n", blocknr, bh_in); 394 err = insert_revoke_hash(journal, blocknr, 395 handle->h_transaction->t_tid); 396 HFSPLUS_BUFFER_TRACE(bh_in, "exit"); 397 return err; 398} 399 400/* 401 * Cancel an outstanding revoke. For use only internally by the 402 * journaling code (called from hfsplus_jbd_get_write_access). 403 * 404 * We trust buffer_hfsplus_jbd_revoked() on the buffer if the buffer is already 405 * being journaled: if there is no revoke pending on the buffer, then we 406 * don't do anything here. 407 * 408 * This would break if it were possible for a buffer to be revoked and 409 * discarded, and then reallocated within the same transaction. In such 410 * a case we would have lost the revoked bit, but when we arrived here 411 * the second time we would still have a pending revoke to cancel. So, 412 * do not trust the Revoked bit on buffers unless RevokeValid is also 413 * set. 414 * 415 * The caller must have the journal locked. 416 */ 417int hfsplus_jbd_cancel_revoke(hfsplus_jbd_handle_t *handle, struct hfsplus_jbd_head *jh) 418{ 419 struct hfsplus_jbd_revoke_record_s *record; 420 hfsplus_jbd_t *journal = handle->h_transaction->t_journal; 421 int need_cancel; 422 int did_revoke = 0; /* akpm: debug */ 423 struct buffer_head *bh = hfsplus_jh2bh(jh); 424 425 hfsplus_jbd_debug(4, "hfsplus_jbd_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 if (test_set_buffer_hfsplus_jbd_revokevalid(bh)) { 432 need_cancel = test_clear_buffer_hfsplus_jbd_revoked(bh); 433 } else { 434 need_cancel = 1; 435 clear_buffer_hfsplus_jbd_revoked(bh); 436 } 437 438 if (need_cancel) { 439 record = find_revoke_record(journal, bh->b_blocknr); 440 if (record) { 441 hfsplus_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 kmem_cache_free(hfsplus_revoke_record_cache, record); 447 did_revoke = 1; 448 } 449 } 450 451#ifdef JBD_EXPENSIVE_CHECKING 452 /* There better not be one left behind by now! */ 453 record = find_revoke_record(journal, bh->b_blocknr); 454 HFSPLUS_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 if (need_cancel) { 462 struct buffer_head *bh2; 463 bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size); 464 if (bh2) { 465 if (bh2 != bh) 466 clear_buffer_hfsplus_jbd_revoked(bh2); 467 __brelse(bh2); 468 } 469 } 470 return did_revoke; 471} 472 473/* hfsplus_jbd_switch_revoke table select j_revoke for next transaction 474 * we do not want to suspend any processing until all revokes are 475 * written -bzzz 476 */ 477void hfsplus_jbd_switch_revoke_table(hfsplus_jbd_t *journal) 478{ 479 int i; 480 481 if (journal->j_revoke == journal->j_revoke_table[0]) 482 journal->j_revoke = journal->j_revoke_table[1]; 483 else 484 journal->j_revoke = journal->j_revoke_table[0]; 485 486 for (i = 0; i < journal->j_revoke->hash_size; i++) 487 INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]); 488} 489 490/* 491 * Write revoke records to the journal for all entries in the current 492 * revoke hash, deleting the entries as we go. 493 * 494 * Called with the journal lock held. 495 */ 496 497void hfsplus_jbd_write_revoke_records(hfsplus_jbd_t *journal, 498 hfsplus_transaction_t *transaction) 499{ 500 struct hfsplus_jbd_head *descriptor; 501 struct hfsplus_jbd_revoke_record_s *record; 502 struct hfsplus_jbd_revoke_table_s *revoke; 503 struct list_head *hash_list; 504 int i, offset, count; 505 506 descriptor = NULL; 507 offset = 0; 508 count = 0; 509 510 /* select revoke table for committing transaction */ 511 revoke = journal->j_revoke == journal->j_revoke_table[0] ? 512 journal->j_revoke_table[1] : journal->j_revoke_table[0]; 513 514 for (i = 0; i < revoke->hash_size; i++) { 515 hash_list = &revoke->hash_table[i]; 516 517 while (!list_empty(hash_list)) { 518 record = (struct hfsplus_jbd_revoke_record_s *) 519 hash_list->next; 520 write_one_revoke_record(journal, transaction, 521 &descriptor, &offset, 522 record); 523 count++; 524 list_del(&record->hash); 525 kmem_cache_free(hfsplus_revoke_record_cache, record); 526 } 527 } 528 if (descriptor) 529 flush_descriptor(journal, descriptor, offset); 530 hfsplus_jbd_debug(1, "Wrote %d revoke records\n", count); 531} 532 533/* 534 * Write out one revoke record. We need to create a new descriptor 535 * block if the old one is full or if we have not already created one. 536 */ 537 538static void write_one_revoke_record(hfsplus_jbd_t *journal, 539 hfsplus_transaction_t *transaction, 540 struct hfsplus_jbd_head **descriptorp, 541 int *offsetp, 542 struct hfsplus_jbd_revoke_record_s *record) 543{ 544 struct hfsplus_jbd_head *descriptor; 545 int offset; 546 hfsplus_jbd_header_t *header; 547 548 /* If we are already aborting, this all becomes a noop. We 549 still need to go round the loop in 550 hfsplus_jbd_write_revoke_records in order to free all of the 551 revoke records: only the IO to the journal is omitted. */ 552 if (is_hfsplus_jbd_aborted(journal)) 553 return; 554 555 descriptor = *descriptorp; 556 offset = *offsetp; 557 558 /* Make sure we have a descriptor with space left for the record */ 559 if (descriptor) { 560 if (offset == journal->j_blocksize) { 561 flush_descriptor(journal, descriptor, offset); 562 descriptor = NULL; 563 } 564 } 565 566 if (!descriptor) { 567 descriptor = hfsplus_jbd_get_descriptor_buffer(journal); 568 if (!descriptor) 569 return; 570printk("@@@@@@@ Oops! .. Need to check it function: %s, Line: %d\n", __FUNCTION__, __LINE__); 571 header = (hfsplus_jbd_header_t *) &hfsplus_jh2bh(descriptor)->b_data[0]; 572 header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); 573 header->h_blocktype = cpu_to_be32(JFS_REVOKE_BLOCK); 574 header->h_sequence = cpu_to_be32(transaction->t_tid); 575 576 /* Record it so that we can wait for IO completion later */ 577 HFSPLUS_JBUFFER_TRACE(descriptor, "file as HFSPLUS_BJ_LogCtl"); 578 hfsplus_jbd_file_buffer(descriptor, transaction, HFSPLUS_BJ_LogCtl); 579 580 offset = sizeof(hfsplus_jbd_revoke_header_t); 581 *descriptorp = descriptor; 582 } 583 584 * ((__be32 *)(&hfsplus_jh2bh(descriptor)->b_data[offset])) = 585 cpu_to_be32(record->blocknr); 586 offset += 4; 587 *offsetp = offset; 588} 589 590/* 591 * Flush a revoke descriptor out to the journal. If we are aborting, 592 * this is a noop; otherwise we are generating a buffer which needs to 593 * be waited for during commit, so it has to go onto the appropriate 594 * journal buffer list. 595 */ 596 597static void flush_descriptor(hfsplus_jbd_t *journal, 598 struct hfsplus_jbd_head *descriptor, 599 int offset) 600{ 601 hfsplus_jbd_revoke_header_t *header; 602 struct buffer_head *bh = hfsplus_jh2bh(descriptor); 603 604 if (is_hfsplus_jbd_aborted(journal)) { 605 put_bh(bh); 606 return; 607 } 608 609 header = (hfsplus_jbd_revoke_header_t *) hfsplus_jh2bh(descriptor)->b_data; 610 header->r_count = cpu_to_be32(offset); 611 set_buffer_hfsplus_jbd_jwrite(bh); 612 HFSPLUS_BUFFER_TRACE(bh, "write"); 613 set_buffer_dirty(bh); 614 ll_rw_block(SWRITE, 1, &bh); 615} 616#endif 617 618/* 619 * Revoke support for recovery. 620 * 621 * Recovery needs to be able to: 622 * 623 * record all revoke records, including the tid of the latest instance 624 * of each revoke in the journal 625 * 626 * check whether a given block in a given transaction should be replayed 627 * (ie. has not been revoked by a revoke record in that or a subsequent 628 * transaction) 629 * 630 * empty the revoke table after recovery. 631 */ 632 633/* 634 * First, setting revoke records. We create a new revoke record for 635 * every block ever revoked in the log as we scan it for recovery, and 636 * we update the existing records if we find multiple revokes for a 637 * single block. 638 */ 639 640int hfsplus_jbd_set_revoke(hfsplus_jbd_t *journal, 641 unsigned long blocknr, 642 hfsplus_jbd_tid_t sequence) 643{ 644 struct hfsplus_jbd_revoke_record_s *record; 645 646 record = find_revoke_record(journal, blocknr); 647 if (record) { 648 /* If we have multiple occurrences, only record the 649 * latest sequence number in the hashed record */ 650 if (hfsplus_tid_gt(sequence, record->sequence)) 651 record->sequence = sequence; 652 return 0; 653 } 654 return insert_revoke_hash(journal, blocknr, sequence); 655} 656 657/* 658 * Test revoke records. For a given block referenced in the log, has 659 * that block been revoked? A revoke record with a given transaction 660 * sequence number revokes all blocks in that transaction and earlier 661 * ones, but later transactions still need replayed. 662 */ 663 664int hfsplus_jbd_test_revoke(hfsplus_jbd_t *journal, 665 unsigned long blocknr, 666 hfsplus_jbd_tid_t sequence) 667{ 668 struct hfsplus_jbd_revoke_record_s *record; 669 670 record = find_revoke_record(journal, blocknr); 671 if (!record) 672 return 0; 673 if (hfsplus_tid_gt(sequence, record->sequence)) 674 return 0; 675 return 1; 676} 677 678/* 679 * Finally, once recovery is over, we need to clear the revoke table so 680 * that it can be reused by the running filesystem. 681 */ 682 683void hfsplus_jbd_clear_revoke(hfsplus_jbd_t *journal) 684{ 685 int i; 686 struct list_head *hash_list; 687 struct hfsplus_jbd_revoke_record_s *record; 688 struct hfsplus_jbd_revoke_table_s *revoke; 689 690 revoke = journal->j_revoke; 691 692 for (i = 0; i < revoke->hash_size; i++) { 693 hash_list = &revoke->hash_table[i]; 694 while (!list_empty(hash_list)) { 695 record = (struct hfsplus_jbd_revoke_record_s*) hash_list->next; 696 list_del(&record->hash); 697 kmem_cache_free(hfsplus_revoke_record_cache, record); 698 } 699 } 700} 701