nfs: make sillyrename an async operation

A synchronous rename can be interrupted by a SIGKILL. If that happens
during a sillyrename operation, it's possible for the rename call to
be sent to the server, but the task exits before processing the
reply. If this happens, the sillyrenamed file won't get cleaned up
during nfs_dentry_iput and the server is left with a dangling .nfs* file
hanging around.

Fix this problem by turning sillyrename into an asynchronous operation
and have the task doing the sillyrename just wait on the reply. If the
task is killed before the sillyrename completes, it'll still proceed
to completion.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index a3c21cc4677b..c46e45e9b33f 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2566,6 +2566,34 @@ static int nfs4_proc_unlink_done(struct rpc_task *task, struct inode *dir)
         return 1;
 }
 
+static void nfs4_proc_rename_setup(struct rpc_message *msg, struct inode *dir)
+{
+        struct nfs_server *server = NFS_SERVER(dir);
+        struct nfs_renameargs *arg = msg->rpc_argp;
+        struct nfs_renameres *res = msg->rpc_resp;
+
+        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME];
+        arg->bitmask = server->attr_bitmask;
+        res->server = server;
+}
+
+static int nfs4_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
+                                 struct inode *new_dir)
+{
+        struct nfs_renameres *res = task->tk_msg.rpc_resp;
+
+        if (!nfs4_sequence_done(task, &res->seq_res))
+                return 0;
+        if (nfs4_async_handle_error(task, res->server, NULL) == -EAGAIN)
+                return 0;
+
+        update_changeattr(old_dir, &res->old_cinfo);
+        nfs_post_op_update_inode(old_dir, res->old_fattr);
+        update_changeattr(new_dir, &res->new_cinfo);
+        nfs_post_op_update_inode(new_dir, res->new_fattr);
+        return 1;
+}
+
 static int _nfs4_proc_rename(struct inode *old_dir, struct qstr *old_name,
                 struct inode *new_dir, struct qstr *new_name)
 {
@@ -5338,6 +5366,8 @@ const struct nfs_rpc_ops nfs_v4_clientops = {
         .unlink_setup   = nfs4_proc_unlink_setup,
         .unlink_done    = nfs4_proc_unlink_done,
         .rename         = nfs4_proc_rename,
+        .rename_setup   = nfs4_proc_rename_setup,
+        .rename_done    = nfs4_proc_rename_done,
         .link           = nfs4_proc_link,
         .symlink        = nfs4_proc_symlink,
         .mkdir          = nfs4_proc_mkdir,