AFS: implement file locking

Implement file locking for AFS.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 116 insertions, 14 deletions

diff --git a/fs/afs/vnode.c b/fs/afs/vnode.c
index 232c55dc245..ac811e445b2 100644
--- a/fs/afs/vnode.c
+++ b/fs/afs/vnode.c
@@ -887,11 +887,6 @@ int afs_vnode_get_volume_status(struct afs_vnode *vnode, struct key *key,
 	       vnode->fid.unique,
 	       key_serial(key));
 
-	/* this op will fetch the status */
-	spin_lock(&vnode->lock);
-	vnode->update_cnt++;
-	spin_unlock(&vnode->lock);
-
 	do {
 		/* pick a server to query */
 		server = afs_volume_pick_fileserver(vnode);
@@ -905,20 +900,127 @@ int afs_vnode_get_volume_status(struct afs_vnode *vnode, struct key *key,
 	} while (!afs_volume_release_fileserver(vnode, server, ret));
 
 	/* adjust the flags */
-	if (ret == 0) {
-		afs_vnode_finalise_status_update(vnode, server);
+	if (ret == 0)
+		afs_put_server(server);
+
+	_leave(" = %d", ret);
+	return ret;
+
+no_server:
+	return PTR_ERR(server);
+}
+
+/*
+ * get a lock on a file
+ */
+int afs_vnode_set_lock(struct afs_vnode *vnode, struct key *key,
+		       afs_lock_type_t type)
+{
+	struct afs_server *server;
+	int ret;
+
+	_enter("%s{%x:%u.%u},%x,%u",
+	       vnode->volume->vlocation->vldb.name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(key), type);
+
+	do {
+		/* pick a server to query */
+		server = afs_volume_pick_fileserver(vnode);
+		if (IS_ERR(server))
+			goto no_server;
+
+		_debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
+
+		ret = afs_fs_set_lock(server, key, vnode, type, &afs_sync_call);
+
+	} while (!afs_volume_release_fileserver(vnode, server, ret));
+
+	/* adjust the flags */
+	if (ret == 0)
+		afs_put_server(server);
+
+	_leave(" = %d", ret);
+	return ret;
+
+no_server:
+	return PTR_ERR(server);
+}
+
+/*
+ * extend a lock on a file
+ */
+int afs_vnode_extend_lock(struct afs_vnode *vnode, struct key *key)
+{
+	struct afs_server *server;
+	int ret;
+
+	_enter("%s{%x:%u.%u},%x",
+	       vnode->volume->vlocation->vldb.name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(key));
+
+	do {
+		/* pick a server to query */
+		server = afs_volume_pick_fileserver(vnode);
+		if (IS_ERR(server))
+			goto no_server;
+
+		_debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
+
+		ret = afs_fs_extend_lock(server, key, vnode, &afs_sync_call);
+
+	} while (!afs_volume_release_fileserver(vnode, server, ret));
+
+	/* adjust the flags */
+	if (ret == 0)
+		afs_put_server(server);
+
+	_leave(" = %d", ret);
+	return ret;
+
+no_server:
+	return PTR_ERR(server);
+}
+
+/*
+ * release a lock on a file
+ */
+int afs_vnode_release_lock(struct afs_vnode *vnode, struct key *key)
+{
+	struct afs_server *server;
+	int ret;
+
+	_enter("%s{%x:%u.%u},%x",
+	       vnode->volume->vlocation->vldb.name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(key));
+
+	do {
+		/* pick a server to query */
+		server = afs_volume_pick_fileserver(vnode);
+		if (IS_ERR(server))
+			goto no_server;
+
+		_debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
+
+		ret = afs_fs_release_lock(server, key, vnode, &afs_sync_call);
+
+	} while (!afs_volume_release_fileserver(vnode, server, ret));
+
+	/* adjust the flags */
+	if (ret == 0)
 		afs_put_server(server);
-	} else {
-		afs_vnode_status_update_failed(vnode, ret);
-	}
 
 	_leave(" = %d", ret);
 	return ret;
 
 no_server:
-	spin_lock(&vnode->lock);
-	vnode->update_cnt--;
-	ASSERTCMP(vnode->update_cnt, >=, 0);
-	spin_unlock(&vnode->lock);
 	return PTR_ERR(server);
 }