diff options
Diffstat (limited to 'source4/lib/tdb/common/lock.c')
| -rw-r--r-- | source4/lib/tdb/common/lock.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/source4/lib/tdb/common/lock.c b/source4/lib/tdb/common/lock.c index 703cfe9dc5..04135a2274 100644 --- a/source4/lib/tdb/common/lock.c +++ b/source4/lib/tdb/common/lock.c @@ -81,6 +81,32 @@ int tdb_brlock_len(struct tdb_context *tdb, tdb_off_t offset, } +/* + upgrade a read lock to a write lock. This needs to be handled in a + special way as some OSes (such as solaris) have too conservative + 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 count = 1000; + while (count--) { + struct timeval tv; + if (tdb_brlock_len(tdb, offset, F_WRLCK, F_SETLKW, 1, len) == 0) { + return 0; + } + if (errno != EDEADLK) { + break; + } + /* sleep for as short a time as we can - more portable than usleep() */ + tv.tv_sec = 0; + tv.tv_usec = 1; + select(0, NULL, NULL, NULL, &tv); + } + return -1; +} + + /* a byte range locking function - return 0 on success this functions locks/unlocks 1 byte at the specified offset. |