The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From da7d554f7c62d0c17c1ac3cc2586473c2d99f0bd Mon Sep 17 00:00:00 2001
From: Alexander Aring aahringo@redhat.com Date: Mon, 26 Oct 2020 10:52:29 -0400 Subject: [PATCH] gfs2: Wake up when sd_glock_disposal becomes zero
Commit fc0e38dae645 ("GFS2: Fix glock deallocation race") fixed a sd_glock_disposal accounting bug by adding a missing atomic_dec statement, but it failed to wake up sd_glock_wait when that decrement causes sd_glock_disposal to reach zero. As a consequence, gfs2_gl_hash_clear can now run into a 10-minute timeout instead of being woken up. Add the missing wakeup.
Fixes: fc0e38dae645 ("GFS2: Fix glock deallocation race") Cc: stable@vger.kernel.org # v2.6.39+ Signed-off-by: Alexander Aring aahringo@redhat.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 5441c17562c5..d98a2e5dab9f 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1078,7 +1078,8 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, out_free: kfree(gl->gl_lksb.sb_lvbptr); kmem_cache_free(cachep, gl); - atomic_dec(&sdp->sd_glock_disposal); + if (atomic_dec_and_test(&sdp->sd_glock_disposal)) + wake_up(&sdp->sd_glock_wait);
out: return ret;