ocfs2/dlm: Fix race in adding/removing lockres' to/from the tracking list

This patch adds a new lock, dlm->tracking_lock, to protect adding/removing
lockres' to/from the dlm->tracking_list. We were previously using dlm->spinlock
for the same, but that proved inadequate as we could be freeing a lockres from
a context that did not hold that lock. As the new lock only protects this list,
we can explicitly take it when removing the lockres from the tracking list.

This bug was exposed when testing multiple processes concurrently flock() the
same file.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This commit is contained in:
Sunil Mushran
2008-12-16 15:49:22 -08:00
committed by Mark Fasheh
parent d4f7e650e5
commit b0d4f817ba
4 changed files with 38 additions and 29 deletions

View File

@@ -140,6 +140,7 @@ struct dlm_ctxt
unsigned int purge_count;
spinlock_t spinlock;
spinlock_t ast_lock;
spinlock_t track_lock;
char *name;
u8 node_num;
u32 key;
@@ -316,6 +317,8 @@ struct dlm_lock_resource
* put on a list for the dlm thread to run. */
unsigned long last_used;
struct dlm_ctxt *dlm;
unsigned migration_pending:1;
atomic_t asts_reserved;
spinlock_t spinlock;