s3:locking: brl_get_locks_internal() should not expose a write lock if the caller...

This triggered deadlocks in the cluster case of brl_get_locks_readonly().

Pair-Programmed-With: Michael Adam <obnox@samba.org>

metze

diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 3cf72ccaf60fa293eabcacaaef9dc9087bd02d71..8033dbad4575db720035fc9a609169bb6748f041 100644 (file)
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -1763,7 +1763,7 @@ int brl_forall(void (*fn)(struct file_id id, struct server_id pid,
  Unlock the record.
 ********************************************************************/
 
-static int byte_range_lock_destructor(struct byte_range_lock *br_lck)
+static void byte_range_lock_flush(struct byte_range_lock *br_lck)
 {
        if (br_lck->read_only) {
                SMB_ASSERT(!br_lck->modified);
@@ -1798,8 +1798,16 @@ static int byte_range_lock_destructor(struct byte_range_lock *br_lck)
 
  done:
 
-       SAFE_FREE(br_lck->lock_data);
+       br_lck->read_only = true;
+       br_lck->modified = false;
+
        TALLOC_FREE(br_lck->record);
+}
+
+static int byte_range_lock_destructor(struct byte_range_lock *br_lck)
+{
+       byte_range_lock_flush(br_lck);
+       SAFE_FREE(br_lck->lock_data);
        return 0;
 }
 
@@ -1814,6 +1822,7 @@ static struct byte_range_lock *brl_get_locks_internal(TALLOC_CTX *mem_ctx,
 {
        TDB_DATA key, data;
        struct byte_range_lock *br_lck = TALLOC_P(mem_ctx, struct byte_range_lock);
+       bool do_read_only = read_only;
 
        if (br_lck == NULL) {
                return NULL;
@@ -1830,18 +1839,17 @@ static struct byte_range_lock *brl_get_locks_internal(TALLOC_CTX *mem_ctx,
        if (!fsp->lockdb_clean) {
                /* We must be read/write to clean
                   the dead entries. */
-               read_only = False;
+               do_read_only = false;
        }
 
-       if (read_only) {
+       if (do_read_only) {
                if (brlock_db->fetch(brlock_db, br_lck, key, &data) == -1) {
                        DEBUG(3, ("Could not fetch byte range lock record\n"));
                        TALLOC_FREE(br_lck);
                        return NULL;
                }
                br_lck->record = NULL;
-       }
-       else {
+       } else {
                br_lck->record = brlock_db->fetch_locked(brlock_db, br_lck, key);
 
                if (br_lck->record == NULL) {
@@ -1853,7 +1861,7 @@ static struct byte_range_lock *brl_get_locks_internal(TALLOC_CTX *mem_ctx,
                data = br_lck->record->value;
        }
 
-       br_lck->read_only = read_only;
+       br_lck->read_only = do_read_only;
        br_lck->lock_data = NULL;
 
        talloc_set_destructor(br_lck, byte_range_lock_destructor);
@@ -1905,6 +1913,15 @@ static struct byte_range_lock *brl_get_locks_internal(TALLOC_CTX *mem_ctx,
                        print_lock_struct(i, &locks[i]);
                }
        }
+
+       if (do_read_only != read_only) {
+               /*
+                * this stores the record and gets rid of
+                * the write lock that is needed for a cleanup
+                */
+               byte_range_lock_flush(br_lck);
+       }
+
        return br_lck;
 }