From a19128260107f951d1b4c421cf98b92f8092b069 Mon Sep 17 00:00:00 2001 From: Sunil Mushran Date: Thu, 21 Jan 2010 10:50:03 -0800 Subject: ocfs2: Prevent a livelock in dlmglue There is possibility of a livelock in __ocfs2_cluster_lock(). If a node were to get an ast for an upconvert request, followed immediately by a bast, there is a small window where the fs may downconvert the lock before the process requesting the upconvert is able to take the lock. This patch adds a new flag to indicate that the upconvert is still in progress and that the dc thread should not downconvert it right now. Wengang Wang and Joel Becker contributed heavily to this patch. Reported-by: David Teigland Signed-off-by: Sunil Mushran Signed-off-by: Joel Becker --- fs/ocfs2/ocfs2.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/ocfs2/ocfs2.h') diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h index 9362eea7424..740f448041e 100644 --- a/fs/ocfs2/ocfs2.h +++ b/fs/ocfs2/ocfs2.h @@ -136,6 +136,10 @@ enum ocfs2_unlock_action { #define OCFS2_LOCK_PENDING (0x00000400) /* This lockres is pending a call to dlm_lock. Only exists with BUSY set. */ +#define OCFS2_LOCK_UPCONVERT_FINISHING (0x00000800) /* blocks the dc thread + * from downconverting + * before the upconvert + * has completed */ struct ocfs2_lock_res_ops; -- cgit v1.2.3-70-g09d2