~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/jbd2/revoke.c

Version: ~ [ linux-5.10-rc1 ] ~ [ linux-5.9.1 ] ~ [ linux-5.8.16 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.72 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.152 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.202 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.240 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.240 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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         ll_rw_block((write_op == WRITE) ? SWRITE : SWRITE_SYNC_PLUG, 1, &bh);
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 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp