GFS2: Fix glock deallocation race
This patch fixes a race in deallocating glocks which was introduced
in the RCU glock patch. We need to ensure that the glock count is
kept correct even in the case that there is a race to add a new
glock into the hash table. Also, to avoid having to wait for an
RCU grace period, the glock counter can be decremented before
call_rcu() is called.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
index c80485c..98c80d8 100644
--- a/fs/gfs2/lock_dlm.c
+++ b/fs/gfs2/lock_dlm.c
@@ -30,7 +30,7 @@
switch (gl->gl_lksb.sb_status) {
case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
- call_rcu(&gl->gl_rcu, gfs2_glock_free);
+ gfs2_glock_free(gl);
return;
case -DLM_ECANCEL: /* Cancel while getting lock */
ret |= LM_OUT_CANCELED;
@@ -165,7 +165,7 @@
int error;
if (gl->gl_lksb.sb_lkid == 0) {
- call_rcu(&gl->gl_rcu, gfs2_glock_free);
+ gfs2_glock_free(gl);
return;
}