r10492: work around a bug in solaris which cases lock upgrades to fail with

EDEADLK even when progress can be made. This is not a good solution,
but I can't find anything better.

diff --git a/source/lib/tdb/common/lock.c b/source/lib/tdb/common/lock.c
index 703cfe9dc5f79e3a5fbf574c452afec14ec46214..04135a22748e31d0943a89f534a8d59b4b3bb2da 100644 (file)
--- a/source/lib/tdb/common/lock.c
+++ b/source/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/source/lib/tdb/common/tdb_private.h b/source/lib/tdb/common/tdb_private.h
index d7471537d89b1f53f02448b7ff8df61bc22488ef..ce105a2a56ae7b9ba37b0d94fa7874f3a73d7f50 100644 (file)
--- a/source/lib/tdb/common/tdb_private.h
+++ b/source/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/source/lib/tdb/common/transaction.c b/source/lib/tdb/common/transaction.c
index cf0f378dcedb36fc76e87c6b3ef5432c2ace76f0..9d370461163895e02edb420090174260b0a0609b 100644 (file)
--- a/source/lib/tdb/common/transaction.c
+++ b/source/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);