[PATCH v6.11-rc1 07/10] dlm: use RSB_HASHED to avoid lookup twice

Alexander Aring
2024-07-29T19:36:46Z

Since commit 01fdeca1cc2d ("dlm: use rcu to avoid an extra rsb struct
lookup") _dlm_master_lookup() is called under rcu lock that prevents
that the rsb structure is being freed. There was a missing change to
avoid an additional lookup and just check that the rsb is still part of
the ls_rsbtbl structure. This patch is doing such check instead of
lookup the rsb structure again.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
fs/dlm/lock.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 30aec123a483..8bf3654f4827 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1308,11 +1308,11 @@ static int _dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *na
}

do_inactive:
- /* unlikely path - relookup under write */
+ /* unlikely path - check if still part of ls_rsbtbl */
write_lock_bh(&ls->ls_rsbtbl_lock);

- error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
- if (!error) {
+ /* see comment in find_rsb_dir */
+ if (rsb_flag(r, RSB_HASHED)) {
if (!rsb_flag(r, RSB_INACTIVE)) {
write_unlock_bh(&ls->ls_rsbtbl_lock);
/* something as changed, very unlikely but
--
2.43.0