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 232c55dc245d..ac811e445b2d 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);
 }