** NOTE! The following LGPL license applies to the tdb
** library. This does NOT imply that all of Samba is released
** under the LGPL
-
+
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
- allow for nested calls to tdb_transaction_start(), re-using the
existing transaction record. If the inner transaction is cancelled
then a subsequent commit will fail
-
+
- keep a mirrored copy of the tdb hash chain heads to allow for the
fast hash heads scan on traverse, updating the mirrored copy in
the transaction version of tdb_write
to reduce this to 3 or even 2 with some more work.
- check for a valid recovery record on open of the tdb, while the
- global lock is held. Automatically recover from the transaction
+ open lock is held. Automatically recover from the transaction
recovery area if needed, then continue with the open as
usual. This allows for smooth crash recovery with no administrator
intervention.
fsync/msync calls are made.
- if TDB_ALLOW_NESTING is passed to flags in tdb open, or added using
- tdb_add_flags() transaction is enabled.
- The default is that transaction nesting is not allowed and an attempt
- to create a nested transaction will fail with TDB_ERR_NESTING.
+ tdb_add_flags() transaction nesting is enabled.
+ It resets the TDB_DISALLOW_NESTING flag, as both cannot be used together.
+ The default is that transaction nesting is allowed.
+ Note: this default may change in future versions of tdb.
Beware. when transactions are nested a transaction successfully
completed with tdb_transaction_commit() can be silently unrolled later.
+
+ - if TDB_DISALLOW_NESTING is passed to flags in tdb open, or added using
+ tdb_add_flags() transaction nesting is disabled.
+ It resets the TDB_ALLOW_NESTING flag, as both cannot be used together.
+ An attempt create a nested transaction will fail with TDB_ERR_NESTING.
+ The default is that transaction nesting is allowed.
+ Note: this default may change in future versions of tdb.
*/
goto fail;
}
}
-
+
/* now copy it out of this block */
memcpy(buf, tdb->transaction->blocks[blk] + (off % tdb->transaction->block_size), len);
if (cv) {
}
}
}
-
+
/* overwrite part of an existing block */
if (buf == NULL) {
memset(tdb->transaction->blocks[blk] + off, 0, len);
return 0;
}
-/*
- brlock during a transaction - ignore them
-*/
-static int transaction_brlock(struct tdb_context *tdb, tdb_off_t offset,
- int rw_type, int lck_type, int probe, size_t len)
-{
- return 0;
-}
-
static const struct tdb_methods transaction_methods = {
transaction_read,
transaction_write,
transaction_next_hash_chain,
transaction_oob,
transaction_expand_file,
- transaction_brlock
};
start a tdb transaction. No token is returned, as only a single
transaction is allowed to be pending per tdb_context
*/
-int tdb_transaction_start(struct tdb_context *tdb)
+static int _tdb_transaction_start(struct tdb_context *tdb,
+ enum tdb_lock_flags lockflags)
{
/* some sanity checks */
if (tdb->read_only || (tdb->flags & TDB_INTERNAL) || tdb->traverse_read) {
return 0;
}
- if (tdb->num_locks != 0 || tdb->global_lock.count) {
+ if (tdb_have_extra_locks(tdb)) {
/* the caller must not have any locks when starting a
transaction as otherwise we'll be screwed by lack
of nested locks in posix */
/* get the transaction write lock. This is a blocking lock. As
discussed with Volker, there are a number of ways we could
make this async, which we will probably do in the future */
- if (tdb_transaction_lock(tdb, F_WRLCK) == -1) {
+ if (tdb_transaction_lock(tdb, F_WRLCK, lockflags) == -1) {
SAFE_FREE(tdb->transaction->blocks);
SAFE_FREE(tdb->transaction);
+ if ((lockflags & TDB_LOCK_WAIT) == 0) {
+ tdb->ecode = TDB_ERR_NOLOCK;
+ }
return -1;
}
-
+
/* get a read lock from the freelist to the end of file. This
is upgraded to a write lock during the commit */
- if (tdb_brlock(tdb, FREELIST_TOP, F_RDLCK, F_SETLKW, 0, 0) == -1) {
+ if (tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, true) == -1) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: failed to get hash locks\n"));
- tdb->ecode = TDB_ERR_LOCK;
- goto fail;
+ goto fail_allrecord_lock;
}
/* setup a copy of the hash table heads so the hash scan in
/* Trace at the end, so we get sequence number correct. */
tdb_trace(tdb, "tdb_transaction_start");
return 0;
-
+
fail:
- tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 0);
- tdb_transaction_unlock(tdb);
+ tdb_allrecord_unlock(tdb, F_RDLCK, false);
+fail_allrecord_lock:
+ tdb_transaction_unlock(tdb, F_WRLCK);
SAFE_FREE(tdb->transaction->blocks);
SAFE_FREE(tdb->transaction->hash_heads);
SAFE_FREE(tdb->transaction);
return -1;
}
+int tdb_transaction_start(struct tdb_context *tdb)
+{
+ return _tdb_transaction_start(tdb, TDB_LOCK_WAIT);
+}
+
+int tdb_transaction_start_nonblock(struct tdb_context *tdb)
+{
+ return _tdb_transaction_start(tdb, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
+}
/*
sync to disk
return 0;
}
- if (fsync(tdb->fd) != 0) {
+ if (fdatasync(tdb->fd) != 0) {
tdb->ecode = TDB_ERR_IO;
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: fsync failed\n"));
return -1;
}
-#ifdef MS_SYNC
+#ifdef HAVE_MMAP
if (tdb->map_ptr) {
tdb_off_t moffset = offset & ~(tdb->page_size-1);
if (msync(moffset + (char *)tdb->map_ptr,
}
-int _tdb_transaction_cancel(struct tdb_context *tdb)
+static int _tdb_transaction_cancel(struct tdb_context *tdb)
{
int i, ret = 0;
if (tdb->transaction->magic_offset) {
const struct tdb_methods *methods = tdb->transaction->io_methods;
- uint32_t zero = 0;
+ const uint32_t invalid = TDB_RECOVERY_INVALID_MAGIC;
/* remove the recovery marker */
- if (methods->tdb_write(tdb, tdb->transaction->magic_offset, &zero, 4) == -1 ||
+ if (methods->tdb_write(tdb, tdb->transaction->magic_offset, &invalid, 4) == -1 ||
transaction_sync(tdb, tdb->transaction->magic_offset, 4) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_cancel: failed to remove recovery magic\n"));
ret = -1;
}
}
- /* remove any global lock created during the transaction */
- if (tdb->global_lock.count != 0) {
- tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 4*tdb->header.hash_size);
- tdb->global_lock.count = 0;
- }
-
- /* remove any locks created during the transaction */
- if (tdb->num_locks != 0) {
- for (i=0;i<tdb->num_lockrecs;i++) {
- tdb_brlock(tdb,FREELIST_TOP+4*tdb->lockrecs[i].list,
- F_UNLCK,F_SETLKW, 0, 1);
- }
- tdb->num_locks = 0;
- tdb->num_lockrecs = 0;
- SAFE_FREE(tdb->lockrecs);
- }
+ /* This also removes the OPEN_LOCK, if we have it. */
+ tdb_release_transaction_locks(tdb);
/* restore the normal io methods */
tdb->methods = tdb->transaction->io_methods;
- tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 0);
- tdb_transaction_unlock(tdb);
SAFE_FREE(tdb->transaction->hash_heads);
SAFE_FREE(tdb->transaction);
-
+
return ret;
}
tdb_off_t *recovery_offset,
tdb_len_t *recovery_max_size)
{
- struct list_struct rec;
+ struct tdb_record rec;
const struct tdb_methods *methods = tdb->transaction->io_methods;
tdb_off_t recovery_head;
rec.rec_len = 0;
- if (recovery_head != 0 &&
- methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n"));
- return -1;
+ if (recovery_head != 0) {
+ if (methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n"));
+ return -1;
+ }
+ /* ignore invalid recovery regions: can happen in crash */
+ if (rec.magic != TDB_RECOVERY_MAGIC &&
+ rec.magic != TDB_RECOVERY_INVALID_MAGIC) {
+ recovery_head = 0;
+ }
}
*recovery_size = tdb_recovery_size(tdb);
tdb_len_t recovery_size;
unsigned char *data, *p;
const struct tdb_methods *methods = tdb->transaction->io_methods;
- struct list_struct *rec;
+ struct tdb_record *rec;
tdb_off_t recovery_offset, recovery_max_size;
tdb_off_t old_map_size = tdb->transaction->old_map_size;
uint32_t magic, tailer;
return -1;
}
- rec = (struct list_struct *)data;
+ rec = (struct tdb_record *)data;
memset(rec, 0, sizeof(*rec));
- rec->magic = 0;
+ rec->magic = TDB_RECOVERY_INVALID_MAGIC;
rec->data_len = recovery_size;
rec->rec_len = recovery_max_size;
rec->key_len = old_map_size;
if (i == tdb->transaction->num_blocks-1) {
length = tdb->transaction->last_block_size;
}
-
+
if (offset >= old_map_size) {
continue;
}
magic = TDB_RECOVERY_MAGIC;
CONVERT(magic);
- *magic_offset = recovery_offset + offsetof(struct list_struct, magic);
+ *magic_offset = recovery_offset + offsetof(struct tdb_record, magic);
if (methods->tdb_write(tdb, *magic_offset, &magic, sizeof(magic)) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_setup_recovery: failed to write recovery magic\n"));
}
methods = tdb->transaction->io_methods;
-
+
/* if there are any locks pending then the caller has not
nested their locks properly, so fail the transaction */
- if (tdb->num_locks || tdb->global_lock.count) {
+ if (tdb_have_extra_locks(tdb)) {
tdb->ecode = TDB_ERR_LOCK;
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: locks pending on commit\n"));
_tdb_transaction_cancel(tdb);
}
/* upgrade the main transaction lock region to a write lock */
- if (tdb_brlock_upgrade(tdb, FREELIST_TOP, 0) == -1) {
+ if (tdb_allrecord_upgrade(tdb) == -1) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to upgrade hash locks\n"));
- tdb->ecode = TDB_ERR_LOCK;
_tdb_transaction_cancel(tdb);
return -1;
}
- /* get the global lock - this prevents new users attaching to the database
+ /* get the open lock - this prevents new users attaching to the database
during the commit */
- if (tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to get global lock\n"));
- tdb->ecode = TDB_ERR_LOCK;
+ if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to get open lock\n"));
_tdb_transaction_cancel(tdb);
return -1;
}
/* write the recovery data to the end of the file */
if (transaction_setup_recovery(tdb, &tdb->transaction->magic_offset) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: failed to setup recovery data\n"));
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
_tdb_transaction_cancel(tdb);
return -1;
}
tdb->transaction->old_map_size) == -1) {
tdb->ecode = TDB_ERR_IO;
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: expansion failed\n"));
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
_tdb_transaction_cancel(tdb);
return -1;
}
methods->tdb_oob(tdb, tdb->map_size + 1, 1);
}
- /* Keep the global lock until the actual commit */
+ /* Keep the open lock until the actual commit */
return 0;
}
if (methods->tdb_write(tdb, offset, tdb->transaction->blocks[i], length) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: write failed during commit\n"));
-
+
/* we've overwritten part of the data and
possibly expanded the file, so we need to
run the crash recovery code */
tdb_transaction_recover(tdb);
_tdb_transaction_cancel(tdb);
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: write failed\n"));
return -1;
return -1;
}
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
-
/*
TODO: maybe write to some dummy hdr field, or write to magic
offset without mmap, before the last sync, instead of the
/*
recover from an aborted transaction. Must be called with exclusive
- database write access already established (including the global
+ database write access already established (including the open
lock to prevent new processes attaching)
*/
int tdb_transaction_recover(struct tdb_context *tdb)
tdb_off_t recovery_head, recovery_eof;
unsigned char *data, *p;
uint32_t zero = 0;
- struct list_struct rec;
+ struct tdb_record rec;
/* find the recovery area */
if (tdb_ofs_read(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) {
}
/* remove the recovery magic */
- if (tdb_ofs_write(tdb, recovery_head + offsetof(struct list_struct, magic),
+ if (tdb_ofs_write(tdb, recovery_head + offsetof(struct tdb_record, magic),
&zero) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to remove recovery magic\n"));
tdb->ecode = TDB_ERR_IO;
return -1;
}
-
- /* reduce the file size to the old size */
- tdb_munmap(tdb);
- if (ftruncate(tdb->fd, recovery_eof) != 0) {
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to reduce to recovery size\n"));
- tdb->ecode = TDB_ERR_IO;
- return -1;
- }
- tdb->map_size = recovery_eof;
- tdb_mmap(tdb);
if (transaction_sync(tdb, 0, recovery_eof) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to sync2 recovery\n"));
/* all done */
return 0;
}
+
+/* Any I/O failures we say "needs recovery". */
+bool tdb_needs_recovery(struct tdb_context *tdb)
+{
+ tdb_off_t recovery_head;
+ struct tdb_record rec;
+
+ /* find the recovery area */
+ if (tdb_ofs_read(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) {
+ return true;
+ }
+
+ if (recovery_head == 0) {
+ /* we have never allocated a recovery record */
+ return false;
+ }
+
+ /* read the recovery record */
+ if (tdb->methods->tdb_read(tdb, recovery_head, &rec,
+ sizeof(rec), DOCONV()) == -1) {
+ return true;
+ }
+
+ return (rec.magic == TDB_RECOVERY_MAGIC);
+}
git.samba.org / sahlberg / ctdb.git / blobdiff