From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Whitehouse Date: Wed, 25 Nov 2009 14:22:26 +0000 Subject: [Cluster-devel] [PATCH 01/30] GFS2: Fix potential race in glock code In-Reply-To: <1259158975-28499-1-git-send-email-swhiteho@redhat.com> References: <1259158975-28499-1-git-send-email-swhiteho@redhat.com> Message-ID: <1259158975-28499-2-git-send-email-swhiteho@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit We need to be careful of the ordering between clearing the GLF_LOCK bit and scheduling the workqueue. Signed-off-by: Steven Whitehouse --- fs/gfs2/glock.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 8b674b1..a3f90ad 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -672,12 +672,17 @@ out: return; out_sched: + clear_bit(GLF_LOCK, &gl->gl_flags); + smp_mb__after_clear_bit(); gfs2_glock_hold(gl); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put_nolock(gl); + return; + out_unlock: clear_bit(GLF_LOCK, &gl->gl_flags); - goto out; + smp_mb__after_clear_bit(); + return; } static void delete_work_func(struct work_struct *work) @@ -1375,10 +1380,11 @@ static int gfs2_shrink_glock_memory(int nr, gfp_t gfp_mask) handle_callback(gl, LM_ST_UNLOCKED, 0); nr--; } + clear_bit(GLF_LOCK, &gl->gl_flags); + smp_mb__after_clear_bit(); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put_nolock(gl); spin_unlock(&gl->gl_spin); - clear_bit(GLF_LOCK, &gl->gl_flags); spin_lock(&lru_lock); continue; } -- 1.6.2.5