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authorVolker Lendecke <vl@samba.org>2008-05-20 21:54:36 +0200
committerJeremy Allison <jra@samba.org>2008-05-20 14:20:42 -0700
commitaa7e4b8e9cafaa5139b5111aa8ca042e6b6f65f4 (patch)
tree0311e25d1b76b84573cf27ac946115e982e0ae94
parent9a975a868e949e61cb011422363cd07b4ec0ce43 (diff)
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Fix nesting tdb_traverse in a transaction
Calling tdb_traverse inside a transaction led to the transaction lock being held indefinitely. This was caused by the tdb_transaction_lock/unlock inside tdb_traverse: The transaction code holds the global lock at offset TRANSACTION_LOCK. The call to tdb_transaction_lock does nothing because the transaction_lock is already being held. tdb_transaction_unlock inside tdb_wrap resets tdb->have_transaction_lock but does not release the kernel-level fcntl lock. transaction_commit later on does not release that fcntl lock either, because tdb->have_transaction_lock was already reset by tdb_transaction(). This patch does fix that problem for me. An alternative would be to make tdb->have_transaction_lock a counter that can cope with proper nesting, maybe in other places as well. Volker (This used to be commit 89543005fe2e4934b3c560c937d49304a32a7fc2)
-rw-r--r--source4/lib/tdb/common/traverse.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/source4/lib/tdb/common/traverse.c b/source4/lib/tdb/common/traverse.c
index 07b0c23858..5a31742e7b 100644
--- a/source4/lib/tdb/common/traverse.c
+++ b/source4/lib/tdb/common/traverse.c
@@ -232,20 +232,25 @@ int tdb_traverse(struct tdb_context *tdb,
{
struct tdb_traverse_lock tl = { NULL, 0, 0, F_WRLCK };
int ret;
+ int in_transaction = (tdb->transaction != NULL);
if (tdb->read_only || tdb->traverse_read) {
return tdb_traverse_read(tdb, fn, private_data);
}
- if (tdb_transaction_lock(tdb, F_WRLCK)) {
- return -1;
+ if (!in_transaction) {
+ if (tdb_transaction_lock(tdb, F_WRLCK)) {
+ return -1;
+ }
}
tdb->traverse_write++;
ret = tdb_traverse_internal(tdb, fn, private_data, &tl);
tdb->traverse_write--;
- tdb_transaction_unlock(tdb);
+ if (!in_transaction) {
+ tdb_transaction_unlock(tdb);
+ }
return ret;
}