From a3a8897bdfb20ae90e77db7e48b90d3c204e2205 Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Fri, 20 Jun 2014 09:36:41 -0400 Subject: [PATCH] GFS2: Only wait for demote when last holder is dequeued Function gfs2_glock_dq_wait is supposed to dequeue a glock and then wait for the lock to be demoted. The problem is, if this is a shared lock, its demote will depend on the other holders, which means you might end up waiting forever because the other process is blocked. This problem is especially apparent when dealing with nested flocks. Signed-off-by: Bob Peterson Signed-off-by: Steven Whitehouse --- fs/gfs2/glock.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index c355f7320e448..278fae5b6982f 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1128,7 +1128,9 @@ void gfs2_glock_dq_wait(struct gfs2_holder *gh) struct gfs2_glock *gl = gh->gh_gl; gfs2_glock_dq(gh); might_sleep(); - wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE); + if (!find_first_holder(gl)) + wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, + TASK_UNINTERRUPTIBLE); } /** -- 2.39.5