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-rw-r--r--lib/tdb/common/lock.c72
-rw-r--r--lib/tdb/common/tdb_private.h7
-rw-r--r--lib/tdb/common/transaction.c12
3 files changed, 62 insertions, 29 deletions
diff --git a/lib/tdb/common/lock.c b/lib/tdb/common/lock.c
index 8401cb7f8f..2a681efc99 100644
--- a/lib/tdb/common/lock.c
+++ b/lib/tdb/common/lock.c
@@ -197,13 +197,29 @@ int tdb_brunlock(struct tdb_context *tdb,
deadlock detection and claim a deadlock when progress can be
made. For those OSes we may loop for a while.
*/
-int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len)
+int tdb_allrecord_upgrade(struct tdb_context *tdb)
{
int count = 1000;
+
+ if (tdb->allrecord_lock.count != 1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_allrecord_upgrade failed: count %u too high\n",
+ tdb->allrecord_lock.count));
+ return -1;
+ }
+
+ if (tdb->allrecord_lock.off != 1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_allrecord_upgrade failed: already upgraded?\n"));
+ return -1;
+ }
+
while (count--) {
struct timeval tv;
- if (tdb_brlock(tdb, F_WRLCK, offset, len,
+ if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0,
TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {
+ tdb->allrecord_lock.ltype = F_WRLCK;
+ tdb->allrecord_lock.off = 0;
return 0;
}
if (errno != EDEADLK) {
@@ -214,7 +230,7 @@ int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len)
tv.tv_usec = 1;
select(0, NULL, NULL, NULL, &tv);
}
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock_upgrade failed at offset %d\n", offset));
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_allrecord_upgrade failed\n"));
return -1;
}
@@ -420,11 +436,10 @@ int tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
}
-
-
-/* lock/unlock entire database */
-static int _tdb_lockall(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags flags)
+/* lock/unlock entire database. It can only be upgradable if you have some
+ * other way of guaranteeing exclusivity (ie. transaction write lock). */
+int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags flags, bool upgradable)
{
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
@@ -449,6 +464,12 @@ static int _tdb_lockall(struct tdb_context *tdb, int ltype,
return -1;
}
+ if (upgradable && ltype != F_RDLCK) {
+ /* tdb error: you can't upgrade a write lock! */
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
if (tdb->methods->brlock(tdb, ltype, FREELIST_TOP, 0, flags)) {
if (flags & TDB_LOCK_WAIT) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno)));
@@ -457,7 +478,10 @@ static int _tdb_lockall(struct tdb_context *tdb, int ltype,
}
tdb->allrecord_lock.count = 1;
- tdb->allrecord_lock.ltype = ltype;
+ /* If it's upgradable, it's actually exclusive so we can treat
+ * it as a write lock. */
+ tdb->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
+ tdb->allrecord_lock.off = upgradable;
return 0;
}
@@ -465,7 +489,7 @@ static int _tdb_lockall(struct tdb_context *tdb, int ltype,
/* unlock entire db */
-static int _tdb_unlockall(struct tdb_context *tdb, int ltype, bool mark_lock)
+int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype, bool mark_lock)
{
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
@@ -473,7 +497,14 @@ static int _tdb_unlockall(struct tdb_context *tdb, int ltype, bool mark_lock)
return -1;
}
- if (tdb->allrecord_lock.ltype != ltype || tdb->allrecord_lock.count == 0) {
+ if (tdb->allrecord_lock.count == 0) {
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
+ /* Upgradable locks are marked as write locks. */
+ if (tdb->allrecord_lock.ltype != ltype
+ && (!tdb->allrecord_lock.off || ltype != F_RDLCK)) {
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
@@ -499,27 +530,27 @@ static int _tdb_unlockall(struct tdb_context *tdb, int ltype, bool mark_lock)
int tdb_lockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall");
- return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_WAIT);
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
}
/* lock entire database with write lock - mark only */
int tdb_lockall_mark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_mark");
- return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY);
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY, false);
}
/* unlock entire database with write lock - unmark only */
int tdb_lockall_unmark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_unmark");
- return _tdb_unlockall(tdb, F_WRLCK, true);
+ return tdb_allrecord_unlock(tdb, F_WRLCK, true);
}
/* lock entire database with write lock - nonblocking varient */
int tdb_lockall_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_NOWAIT);
+ int ret = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_NOWAIT, false);
tdb_trace_ret(tdb, "tdb_lockall_nonblock", ret);
return ret;
}
@@ -528,20 +559,20 @@ int tdb_lockall_nonblock(struct tdb_context *tdb)
int tdb_unlockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall");
- return _tdb_unlockall(tdb, F_WRLCK, false);
+ return tdb_allrecord_unlock(tdb, F_WRLCK, false);
}
/* lock entire database with read lock */
int tdb_lockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_read");
- return _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_WAIT);
+ return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
}
/* lock entire database with read lock - nonblock varient */
int tdb_lockall_read_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_NOWAIT);
+ int ret = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_NOWAIT, false);
tdb_trace_ret(tdb, "tdb_lockall_read_nonblock", ret);
return ret;
}
@@ -550,7 +581,7 @@ int tdb_lockall_read_nonblock(struct tdb_context *tdb)
int tdb_unlockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall_read");
- return _tdb_unlockall(tdb, F_RDLCK, false);
+ return tdb_allrecord_unlock(tdb, F_RDLCK, false);
}
/* lock/unlock one hash chain. This is meant to be used to reduce
@@ -670,7 +701,8 @@ bool tdb_have_extra_locks(struct tdb_context *tdb)
{
unsigned int extra = tdb->num_lockrecs;
- if (tdb->allrecord_lock.count) {
+ /* A transaction holds the lock for all records. */
+ if (!tdb->transaction && tdb->allrecord_lock.count) {
return true;
}
diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h
index 0ac37dfa5d..013c2f022e 100644
--- a/lib/tdb/common/tdb_private.h
+++ b/lib/tdb/common/tdb_private.h
@@ -191,7 +191,7 @@ struct tdb_context {
int read_only; /* opened read-only */
int traverse_read; /* read-only traversal */
int traverse_write; /* read-write traversal */
- struct tdb_lock_type allrecord_lock;
+ struct tdb_lock_type allrecord_lock; /* .offset == upgradable */
int num_lockrecs;
struct tdb_lock_type *lockrecs; /* only real locks, all with count>0 */
enum TDB_ERROR ecode; /* error code for last tdb error */
@@ -236,7 +236,10 @@ bool tdb_have_extra_locks(struct tdb_context *tdb);
void tdb_release_extra_locks(struct tdb_context *tdb);
int tdb_transaction_lock(struct tdb_context *tdb, int ltype);
int tdb_transaction_unlock(struct tdb_context *tdb, int ltype);
-int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len);
+int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags flags, bool upgradable);
+int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype, bool mark_lock);
+int tdb_allrecord_upgrade(struct tdb_context *tdb);
int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);
int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off);
int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
diff --git a/lib/tdb/common/transaction.c b/lib/tdb/common/transaction.c
index 69a622dae0..c9718a59b3 100644
--- a/lib/tdb/common/transaction.c
+++ b/lib/tdb/common/transaction.c
@@ -502,10 +502,9 @@ int tdb_transaction_start(struct tdb_context *tdb)
/* 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, F_RDLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT) == -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
@@ -538,7 +537,8 @@ int tdb_transaction_start(struct tdb_context *tdb)
return 0;
fail:
- tdb_brunlock(tdb, F_RDLCK, FREELIST_TOP, 0);
+ 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);
@@ -621,7 +621,6 @@ static int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype)
/* restore the normal io methods */
tdb->methods = tdb->transaction->io_methods;
- tdb_brunlock(tdb, ltype, FREELIST_TOP, 0);
tdb_transaction_unlock(tdb, F_WRLCK);
SAFE_FREE(tdb->transaction->hash_heads);
SAFE_FREE(tdb->transaction);
@@ -938,9 +937,8 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *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, F_RDLCK);
return -1;
}
generated by cgit (git 2.34.1) at 2024-11-20 02:00:21 +0000