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authorMark Fasheh <mfasheh@suse.com>2008-07-22 01:29:16 +0400
committerMark Fasheh <mfasheh@suse.com>2008-10-14 00:57:57 +0400
commit53da4939f349d4edd283b043219221ca5b78e4d4 (patch)
tree3e0f8e1bd5474822431cffd1e449df9b639e1772 /fs/ocfs2/stack_user.c
parenta447c0932445f92ce6f4c1bd020f62c5097a7842 (diff)
downloadlinux-53da4939f349d4edd283b043219221ca5b78e4d4.tar.xz
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>
Diffstat (limited to 'fs/ocfs2/stack_user.c')
-rw-r--r--fs/ocfs2/stack_user.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index 353fc35c6748..faec2d879357 100644
--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -28,6 +28,7 @@
#include "ocfs2.h" /* For struct ocfs2_lock_res */
#include "stackglue.h"
+#include <linux/dlm_plock.h>
/*
* The control protocol starts with a handshake. Until the handshake
@@ -746,6 +747,37 @@ static void user_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
{
}
+static int user_plock(struct ocfs2_cluster_connection *conn,
+ u64 ino,
+ struct file *file,
+ int cmd,
+ struct file_lock *fl)
+{
+ /*
+ * This more or less just demuxes the plock request into any
+ * one of three dlm calls.
+ *
+ * Internally, fs/dlm will pass these to a misc device, which
+ * a userspace daemon will read and write to.
+ *
+ * For now, cancel requests (which happen internally only),
+ * are turned into unlocks. Most of this function taken from
+ * gfs2_lock.
+ */
+
+ if (cmd == F_CANCELLK) {
+ cmd = F_SETLK;
+ fl->fl_type = F_UNLCK;
+ }
+
+ if (IS_GETLK(cmd))
+ return dlm_posix_get(conn->cc_lockspace, ino, file, fl);
+ else if (fl->fl_type == F_UNLCK)
+ return dlm_posix_unlock(conn->cc_lockspace, ino, file, fl);
+ else
+ return dlm_posix_lock(conn->cc_lockspace, ino, file, cmd, fl);
+}
+
/*
* Compare a requested locking protocol version against the current one.
*
@@ -839,6 +871,7 @@ static struct ocfs2_stack_operations ocfs2_user_plugin_ops = {
.dlm_unlock = user_dlm_unlock,
.lock_status = user_dlm_lock_status,
.lock_lvb = user_dlm_lvb,
+ .plock = user_plock,
.dump_lksb = user_dlm_dump_lksb,
};