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authorBob Peterson <rpeterso@redhat.com>2014-06-20 09:36:41 -0400
committerSteven Whitehouse <swhiteho@redhat.com>2014-07-18 11:12:14 +0100
commit79272b3562bb44ce7dc720cd13136f5a4a53c618 (patch)
tree7339b1d87039d77346d9a4ec3fb2be3316c6be81
parent3c8fb50445833b93f69b6b703a29aae3523cad0c (diff)
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 <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
-rw-r--r--fs/gfs2/glock.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index c355f7320e44..278fae5b6982 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);
}
/**