ocfs2: POSIX file locks support
This is actually pretty easy since fs/dlm already handles the bulk of the
work. The Ocfs2 userspace cluster stack module already uses fs/dlm as the
underlying lock manager, so I only had to add the right calls.
Cluster-aware POSIX locks ("plocks") can be turned off by the same means at
UNIX locks - mount with 'noflocks', or create a local-only Ocfs2 volume.
Internally, the file system uses two sets of file_operations, depending on
whether cluster aware plocks is required. This turns out to be easier than
implementing local-only versions of ->lock.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/stackglue.h b/fs/ocfs2/stackglue.h
index db56281..c571af3 100644
--- a/fs/ocfs2/stackglue.h
+++ b/fs/ocfs2/stackglue.h
@@ -28,6 +28,10 @@
#include "dlm/dlmapi.h"
#include <linux/dlm.h>
+/* Needed for plock-related prototypes */
+struct file;
+struct file_lock;
+
/*
* dlmconstants.h does not have a LOCAL flag. We hope to remove it
* some day, but right now we need it. Let's fake it. This value is larger
@@ -187,6 +191,17 @@
void *(*lock_lvb)(union ocfs2_dlm_lksb *lksb);
/*
+ * Cluster-aware posix locks
+ *
+ * This is NULL for stacks which do not support posix locks.
+ */
+ int (*plock)(struct ocfs2_cluster_connection *conn,
+ u64 ino,
+ struct file *file,
+ int cmd,
+ struct file_lock *fl);
+
+ /*
* This is an optoinal debugging hook. If provided, the
* stack can dump debugging information about this lock.
*/
@@ -240,6 +255,10 @@
void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb);
void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb);
+int ocfs2_stack_supports_plocks(void);
+int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
+ struct file *file, int cmd, struct file_lock *fl);
+
void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto);