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ocfs2: POSIX file locks support

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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>
This commit is contained in:
Mark Fasheh
2008-07-21 14:29:16 -07:00
parent a447c09324
commit 53da4939f3
8 changed files with 155 additions and 3 deletions
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19
fs/ocfs2/stackglue.h
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@@ -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
@@ -186,6 +190,17 @@ struct ocfs2_stack_operations {
*/
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 @@ int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb);
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);