Commit 7e71c55e authored by Steven Whitehouse's avatar Steven Whitehouse

GFS2: Fix potential race in glock code

We need to be careful of the ordering between clearing the
GLF_LOCK bit and scheduling the workqueue.
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 22763c5c
......@@ -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;
}
......
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