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authorSunil Mushran <sunil.mushran@oracle.com>2010-01-21 10:50:03 -0800
committerJoel Becker <joel.becker@oracle.com>2010-02-02 23:51:13 -0800
commita19128260107f951d1b4c421cf98b92f8092b069 (patch)
tree0e98386142589c986fe433e1dd390f4a21db7bc9 /fs/ocfs2/ocfs2.h
parent0b94a909eb2e2f6990d05fd486a0cb4902ef1ae7 (diff)
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 <wen.gang.wang@oracle.com> and Joel Becker <joel.becker@oracle.com> contributed heavily to this patch. Reported-by: David Teigland <teigland@redhat.com> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs/ocfs2/ocfs2.h')
-rw-r--r--fs/ocfs2/ocfs2.h4
1 files changed, 4 insertions, 0 deletions
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;