/*
* linux/fs/revoke.c
- *
+ *
* Written by Stephen C. Tweedie <sct@redhat.com>, 2000
*
* Copyright 2000 Red Hat corp --- All Rights Reserved
* Revoke is the mechanism used to prevent old log records for deleted
* metadata from being replayed on top of newer data using the same
* blocks. The revoke mechanism is used in two separate places:
- *
+ *
* + Commit: during commit we write the entire list of the current
* transaction's revoked blocks to the journal
- *
+ *
* + Recovery: during recovery we record the transaction ID of all
* revoked blocks. If there are multiple revoke records in the log
* for a single block, only the last one counts, and if there is a log
* single transaction:
*
* Block is revoked and then journaled:
- * The desired end result is the journaling of the new block, so we
+ * The desired end result is the journaling of the new block, so we
* cancel the revoke before the transaction commits.
*
* Block is journaled and then revoked:
* transaction must have happened after the block was journaled and so
* the revoke must take precedence.
*
- * Block is revoked and then written as data:
+ * Block is revoked and then written as data:
* The data write is allowed to succeed, but the revoke is _not_
* cancelled. We still need to prevent old log records from
* overwriting the new data. We don't even need to clear the revoke
* buffer has not been revoked, and cancel_revoke
* need do nothing.
* RevokeValid set, Revoked set:
- * buffer has been revoked.
+ * buffer has been revoked.
*/
#ifndef __KERNEL__
+#include "config.h"
#include "jfs_user.h"
#else
#include <linux/sched.h>
journal replay, this involves recording the transaction ID of the
last transaction to revoke this block. */
-struct jbd_revoke_record_s
+struct jbd_revoke_record_s
{
struct list_head hash;
tid_t sequence; /* Used for recovery only */
- unsigned long blocknr;
+ unsigned long blocknr;
};
{
/* It is conceivable that we might want a larger hash table
* for recovery. Must be a power of two. */
- int hash_size;
- int hash_shift;
+ int hash_size;
+ int hash_shift;
struct list_head *hash_table;
};
{
struct jbd_revoke_table_s *table = journal->j_revoke;
int hash_shift = table->hash_shift;
-
+
return ((block << (hash_shift - 6)) ^
(block >> 13) ^
(block << (hash_shift - 12))) & (table->hash_size - 1);
{
struct list_head *hash_list;
struct jbd_revoke_record_s *record;
-
+
hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
record = (struct jbd_revoke_record_s *) hash_list->next;
return -ENOMEM;
}
return 0;
-}
+}
void journal_destroy_revoke_caches(void)
{
int journal_init_revoke(journal_t *journal, int hash_size)
{
int shift, tmp;
-
+
J_ASSERT (journal->j_revoke == NULL);
-
+
journal->j_revoke = kmem_cache_alloc(revoke_table_cache, GFP_KERNEL);
if (!journal->j_revoke)
return -ENOMEM;
-
+
/* Check that the hash_size is a power of two */
J_ASSERT ((hash_size & (hash_size-1)) == 0);
journal->j_revoke = NULL;
return -ENOMEM;
}
-
+
for (tmp = 0; tmp < hash_size; tmp++)
INIT_LIST_HEAD(&journal->j_revoke->hash_table[tmp]);
-
+
return 0;
}
struct jbd_revoke_table_s *table;
struct list_head *hash_list;
int i;
-
+
table = journal->j_revoke;
if (!table)
return;
-
+
for (i=0; i<table->hash_size; i++) {
hash_list = &table->hash_table[i];
J_ASSERT (list_empty(hash_list));
}
-
+
kfree(table->hash_table);
kmem_cache_free(revoke_table_cache, table);
journal->j_revoke = NULL;
#ifdef __KERNEL__
-/*
+/*
* journal_revoke: revoke a given buffer_head from the journal. This
* prevents the block from being replayed during recovery if we take a
* crash after this current transaction commits. Any subsequent
* metadata writes of the buffer in this transaction cancel the
- * revoke.
+ * revoke.
*
* Note that this call may block --- it is up to the caller to make
* sure that there are no further calls to journal_write_metadata
* before the revoke is complete. In ext3, this implies calling the
* revoke before clearing the block bitmap when we are deleting
- * metadata.
+ * metadata.
*
* Revoke performs a journal_forget on any buffer_head passed in as a
* parameter, but does _not_ forget the buffer_head if the bh was only
- * found implicitly.
+ * found implicitly.
*
* bh_in may not be a journalled buffer - it may have come off
* the hash tables without an attached journal_head.
* by one.
*/
-int journal_revoke(handle_t *handle, unsigned long blocknr,
+int journal_revoke(handle_t *handle, unsigned long blocknr,
struct buffer_head *bh_in)
{
struct buffer_head *bh = NULL;
int need_cancel;
int did_revoke = 0; /* akpm: debug */
struct buffer_head *bh = jh2bh(jh);
-
+
jbd_debug(4, "journal_head %p, cancelling revoke\n", jh);
/* Is the existing Revoke bit valid? If so, we trust it, and
__brelse(bh2);
}
}
-
+
return did_revoke;
}
* Called with the journal lock held.
*/
-void journal_write_revoke_records(journal_t *journal,
+void journal_write_revoke_records(journal_t *journal,
transaction_t *transaction)
{
struct journal_head *descriptor;
struct list_head *hash_list;
int i, offset, count;
- descriptor = NULL;
+ descriptor = NULL;
offset = 0;
count = 0;
revoke = journal->j_revoke;
-
+
for (i = 0; i < revoke->hash_size; i++) {
hash_list = &revoke->hash_table[i];
while (!list_empty(hash_list)) {
- record = (struct jbd_revoke_record_s *)
+ record = (struct jbd_revoke_record_s *)
hash_list->next;
write_one_revoke_record(journal, transaction,
- &descriptor, &offset,
+ &descriptor, &offset,
record);
count++;
list_del(&record->hash);
kmem_cache_free(revoke_record_cache, record);
}
}
- if (descriptor)
+ if (descriptor)
flush_descriptor(journal, descriptor, offset);
jbd_debug(1, "Wrote %d revoke records\n", count);
}
-/*
+/*
* Write out one revoke record. We need to create a new descriptor
- * block if the old one is full or if we have not already created one.
+ * block if the old one is full or if we have not already created one.
*/
-static void write_one_revoke_record(journal_t *journal,
+static void write_one_revoke_record(journal_t *journal,
transaction_t *transaction,
- struct journal_head **descriptorp,
+ struct journal_head **descriptorp,
int *offsetp,
struct jbd_revoke_record_s *record)
{
descriptor = NULL;
}
}
-
+
if (!descriptor) {
descriptor = journal_get_descriptor_buffer(journal);
if (!descriptor)
offset = sizeof(journal_revoke_header_t);
*descriptorp = descriptor;
}
-
- * ((unsigned int *)(&jh2bh(descriptor)->b_data[offset])) =
+
+ * ((unsigned int *)(&jh2bh(descriptor)->b_data[offset])) =
htonl(record->blocknr);
offset += 4;
*offsetp = offset;
}
-/*
+/*
* Flush a revoke descriptor out to the journal. If we are aborting,
* this is a noop; otherwise we are generating a buffer which needs to
* be waited for during commit, so it has to go onto the appropriate
* journal buffer list.
*/
-static void flush_descriptor(journal_t *journal,
- struct journal_head *descriptor,
+static void flush_descriptor(journal_t *journal,
+ struct journal_head *descriptor,
int offset)
{
journal_revoke_header_t *header;
__brelse(jh2bh(descriptor));
return;
}
-
+
header = (journal_revoke_header_t *) jh2bh(descriptor)->b_data;
header->r_count = htonl(offset);
set_bit(BH_JWrite, &jh2bh(descriptor)->b_state);
#endif
-/*
+/*
* Revoke support for recovery.
*
* Recovery needs to be able to:
* check whether a given block in a given transaction should be replayed
* (ie. has not been revoked by a revoke record in that or a subsequent
* transaction)
- *
+ *
* empty the revoke table after recovery.
*/
* First, setting revoke records. We create a new revoke record for
* every block ever revoked in the log as we scan it for recovery, and
* we update the existing records if we find multiple revokes for a
- * single block.
+ * single block.
*/
-int journal_set_revoke(journal_t *journal,
- unsigned long blocknr,
+int journal_set_revoke(journal_t *journal,
+ unsigned long blocknr,
tid_t sequence)
{
struct jbd_revoke_record_s *record;
-
+
record = find_revoke_record(journal, blocknr);
if (record) {
/* If we have multiple occurences, only record the
if (tid_gt(sequence, record->sequence))
record->sequence = sequence;
return 0;
- }
+ }
return insert_revoke_hash(journal, blocknr, sequence);
}
-/*
+/*
* Test revoke records. For a given block referenced in the log, has
* that block been revoked? A revoke record with a given transaction
* sequence number revokes all blocks in that transaction and earlier
* ones, but later transactions still need replayed.
*/
-int journal_test_revoke(journal_t *journal,
+int journal_test_revoke(journal_t *journal,
unsigned long blocknr,
tid_t sequence)
{
struct jbd_revoke_record_s *record;
-
+
record = find_revoke_record(journal, blocknr);
if (!record)
return 0;
struct list_head *hash_list;
struct jbd_revoke_record_s *record;
struct jbd_revoke_table_s *revoke;
-
+
revoke = journal->j_revoke;
-
+
for (i = 0; i < revoke->hash_size; i++) {
hash_list = &revoke->hash_table[i];
while (!list_empty(hash_list)) {
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff