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-rw-r--r--source4/lib/tdb/common/lock.c26
-rw-r--r--source4/lib/tdb/common/tdb_private.h1
-rw-r--r--source4/lib/tdb/common/transaction.c2
3 files changed, 28 insertions, 1 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.
diff --git a/source4/lib/tdb/common/tdb_private.h b/source4/lib/tdb/common/tdb_private.h
index d7471537d8..ce105a2a56 100644
--- a/source4/lib/tdb/common/tdb_private.h
+++ b/source4/lib/tdb/common/tdb_private.h
@@ -216,6 +216,7 @@ void tdb_mmap(struct tdb_context *tdb);
int tdb_lock(struct tdb_context *tdb, int list, int ltype);
int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset, int rw_type, int lck_type, int probe);
+int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len);
int tdb_brlock_len(struct tdb_context *tdb, tdb_off_t offset,
int rw_type, int lck_type, int probe, size_t len);
int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);
diff --git a/source4/lib/tdb/common/transaction.c b/source4/lib/tdb/common/transaction.c
index cf0f378dce..9d37046116 100644
--- a/source4/lib/tdb/common/transaction.c
+++ b/source4/lib/tdb/common/transaction.c
@@ -772,7 +772,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
}
/* upgrade the main transaction lock region to a write lock */
- if (tdb_brlock_len(tdb, FREELIST_TOP, F_WRLCK, F_SETLKW, 0, 0) == -1) {
+ if (tdb_brlock_upgrade(tdb, FREELIST_TOP, 0) == -1) {
TDB_LOG((tdb, 0, "tdb_transaction_start: failed to upgrade hash locks\n"));
tdb->ecode = TDB_ERR_LOCK;
tdb_transaction_cancel(tdb);