diff options
Diffstat (limited to 'source3/lib/tdb/common/lock.c')
| -rw-r--r-- | source3/lib/tdb/common/lock.c | 147 |
1 files changed, 135 insertions, 12 deletions
diff --git a/source3/lib/tdb/common/lock.c b/source3/lib/tdb/common/lock.c index 43be5d20e1..e3fe888c46 100644 --- a/source3/lib/tdb/common/lock.c +++ b/source3/lib/tdb/common/lock.c @@ -27,6 +27,8 @@ #include "tdb_private.h" +#define TDB_MARK_LOCK 0x80000000 + void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr) { tdb->interrupt_sig_ptr = ptr; @@ -116,10 +118,13 @@ int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len) /* lock a list in the database. list -1 is the alloc list */ -int tdb_lock(struct tdb_context *tdb, int list, int ltype) +static int _tdb_lock(struct tdb_context *tdb, int list, int ltype, int op) { struct tdb_lock_type *new_lck; int i; + bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); + + ltype &= ~TDB_MARK_LOCK; /* a global lock allows us to avoid per chain locks */ if (tdb->global_lock.count && @@ -169,10 +174,9 @@ int tdb_lock(struct tdb_context *tdb, int list, int ltype) /* Since fcntl locks don't nest, we do a lock for the first one, and simply bump the count for future ones */ - if (tdb->methods->tdb_brlock(tdb,FREELIST_TOP+4*list,ltype,F_SETLKW, + if (!mark_lock && + tdb->methods->tdb_brlock(tdb,FREELIST_TOP+4*list, ltype, op, 0, 1)) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d " - "ltype=%d (%s)\n", list, ltype, strerror(errno))); return -1; } @@ -186,6 +190,25 @@ int tdb_lock(struct tdb_context *tdb, int list, int ltype) return 0; } +/* lock a list in the database. list -1 is the alloc list */ +int tdb_lock(struct tdb_context *tdb, int list, int ltype) +{ + int ret; + ret = _tdb_lock(tdb, list, ltype, F_SETLKW); + if (ret) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d " + "ltype=%d (%s)\n", list, ltype, strerror(errno))); + } + return ret; +} + +/* lock a list in the database. list -1 is the alloc list. non-blocking lock */ +int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype) +{ + return _tdb_lock(tdb, list, ltype, F_SETLK); +} + + /* unlock the database: returns void because it's too late for errors. */ /* changed to return int it may be interesting to know there has been an error --simo */ @@ -194,6 +217,9 @@ int tdb_unlock(struct tdb_context *tdb, int list, int ltype) int ret = -1; int i; struct tdb_lock_type *lck = NULL; + bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); + + ltype &= ~TDB_MARK_LOCK; /* a global lock allows us to avoid per chain locks */ if (tdb->global_lock.count && @@ -238,8 +264,12 @@ int tdb_unlock(struct tdb_context *tdb, int list, int ltype) * anyway. */ - ret = tdb->methods->tdb_brlock(tdb, FREELIST_TOP+4*list, F_UNLCK, - F_SETLKW, 0, 1); + if (mark_lock) { + ret = 0; + } else { + ret = tdb->methods->tdb_brlock(tdb, FREELIST_TOP+4*list, F_UNLCK, + F_SETLKW, 0, 1); + } tdb->num_locks--; /* @@ -266,11 +296,50 @@ int tdb_unlock(struct tdb_context *tdb, int list, int ltype) return ret; } +/* + get the transaction lock + */ +int tdb_transaction_lock(struct tdb_context *tdb, int ltype) +{ + if (tdb->have_transaction_lock || tdb->global_lock.count) { + return 0; + } + if (tdb->methods->tdb_brlock(tdb, TRANSACTION_LOCK, ltype, + F_SETLKW, 0, 1) == -1) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_lock: failed to get transaction lock\n")); + tdb->ecode = TDB_ERR_LOCK; + return -1; + } + tdb->have_transaction_lock = 1; + return 0; +} + +/* + release the transaction lock + */ +int tdb_transaction_unlock(struct tdb_context *tdb) +{ + int ret; + if (!tdb->have_transaction_lock) { + return 0; + } + ret = tdb->methods->tdb_brlock(tdb, TRANSACTION_LOCK, F_UNLCK, F_SETLKW, 0, 1); + if (ret == 0) { + tdb->have_transaction_lock = 0; + } + return ret; +} + + /* lock/unlock entire database */ -static int _tdb_lockall(struct tdb_context *tdb, int ltype) +static int _tdb_lockall(struct tdb_context *tdb, int ltype, int op) { + bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); + + ltype &= ~TDB_MARK_LOCK; + /* There are no locks on read-only dbs */ if (tdb->read_only || tdb->traverse_read) return TDB_ERRCODE(TDB_ERR_LOCK, -1); @@ -290,9 +359,12 @@ static int _tdb_lockall(struct tdb_context *tdb, int ltype) return TDB_ERRCODE(TDB_ERR_LOCK, -1); } - if (tdb->methods->tdb_brlock(tdb, FREELIST_TOP, ltype, F_SETLKW, + if (!mark_lock && + tdb->methods->tdb_brlock(tdb, FREELIST_TOP, ltype, op, 0, 4*tdb->header.hash_size)) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno))); + if (op == F_SETLKW) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno))); + } return -1; } @@ -302,9 +374,15 @@ static int _tdb_lockall(struct tdb_context *tdb, int ltype) return 0; } + + /* unlock entire db */ static int _tdb_unlockall(struct tdb_context *tdb, int ltype) { + bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); + + ltype &= ~TDB_MARK_LOCK; + /* There are no locks on read-only dbs */ if (tdb->read_only || tdb->traverse_read) { return TDB_ERRCODE(TDB_ERR_LOCK, -1); @@ -319,7 +397,8 @@ static int _tdb_unlockall(struct tdb_context *tdb, int ltype) return 0; } - if (tdb->methods->tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, + if (!mark_lock && + tdb->methods->tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 4*tdb->header.hash_size)) { TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed (%s)\n", strerror(errno))); return -1; @@ -334,7 +413,25 @@ static int _tdb_unlockall(struct tdb_context *tdb, int ltype) /* lock entire database with write lock */ int tdb_lockall(struct tdb_context *tdb) { - return _tdb_lockall(tdb, F_WRLCK); + return _tdb_lockall(tdb, F_WRLCK, F_SETLKW); +} + +/* lock entire database with write lock - mark only */ +int tdb_lockall_mark(struct tdb_context *tdb) +{ + return _tdb_lockall(tdb, F_WRLCK | TDB_MARK_LOCK, F_SETLKW); +} + +/* unlock entire database with write lock - unmark only */ +int tdb_lockall_unmark(struct tdb_context *tdb) +{ + return _tdb_unlockall(tdb, F_WRLCK | TDB_MARK_LOCK); +} + +/* lock entire database with write lock - nonblocking varient */ +int tdb_lockall_nonblock(struct tdb_context *tdb) +{ + return _tdb_lockall(tdb, F_WRLCK, F_SETLK); } /* unlock entire database with write lock */ @@ -346,7 +443,13 @@ int tdb_unlockall(struct tdb_context *tdb) /* lock entire database with read lock */ int tdb_lockall_read(struct tdb_context *tdb) { - return _tdb_lockall(tdb, F_RDLCK); + return _tdb_lockall(tdb, F_RDLCK, F_SETLKW); +} + +/* lock entire database with read lock - nonblock varient */ +int tdb_lockall_read_nonblock(struct tdb_context *tdb) +{ + return _tdb_lockall(tdb, F_RDLCK, F_SETLK); } /* unlock entire database with read lock */ @@ -362,6 +465,26 @@ int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key) return tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK); } +/* lock/unlock one hash chain, non-blocking. This is meant to be used + to reduce contention - it cannot guarantee how many records will be + locked */ +int tdb_chainlock_nonblock(struct tdb_context *tdb, TDB_DATA key) +{ + return tdb_lock_nonblock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK); +} + +/* mark a chain as locked without actually locking it. Warning! use with great caution! */ +int tdb_chainlock_mark(struct tdb_context *tdb, TDB_DATA key) +{ + return tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK); +} + +/* unmark a chain as locked without actually locking it. Warning! use with great caution! */ +int tdb_chainlock_unmark(struct tdb_context *tdb, TDB_DATA key) +{ + return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK); +} + int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key) { return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK); |