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

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

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

metze
This commit is contained in:
Stefan Metzmacher 2011-03-17 10:04:12 +01:00
parent c4cfffa4ed
commit e8411d6f9f
1 changed files with 24 additions and 7 deletions
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31
source3/locking/brlock.c
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@ -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;
}