NFS: Add softreval behaviour to nfs_lookup_revalidate()

If the server is unavaliable, we want to allow the revalidating
lookup to time out, and to default to validating the cached dentry
if the 'softreval' mount option is set.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/dir.c

@@ -1142,10 +1142,17 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
 	if (fhandle == NULL || fattr == NULL || IS_ERR(label))
 		goto out;
 
-	ret = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label);
+	ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label);
 	if (ret < 0) {
-		if (ret == -ESTALE || ret == -ENOENT)
+		switch (ret) {
+		case -ESTALE:
+		case -ENOENT:
 			ret = 0;
+			break;
+		case -ETIMEDOUT:
+			if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL)
+				ret = 1;
+		}
 		goto out;
 	}
 	ret = 0;
@@ -1408,7 +1415,7 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in
 		goto out;
 
 	trace_nfs_lookup_enter(dir, dentry, flags);
-	error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label);
+	error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label);
 	if (error == -ENOENT)
 		goto no_entry;
 	if (error < 0) {
@@ -1683,7 +1690,7 @@ nfs_add_or_obtain(struct dentry *dentry, struct nfs_fh *fhandle,
 	d_drop(dentry);
 
 	if (fhandle->size == 0) {
-		error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, NULL);
+		error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, NULL);
 		if (error)
 			goto out_error;
 	}

fs/nfs/internal.h

@@ -33,6 +33,15 @@ static inline int nfs_attr_use_mounted_on_fileid(struct nfs_fattr *fattr)
 	return 1;
 }
 
+static inline bool nfs_lookup_is_soft_revalidate(const struct dentry *dentry)
+{
+	if (!(NFS_SB(dentry->d_sb)->flags & NFS_MOUNT_SOFTREVAL))
+		return false;
+	if (!d_is_positive(dentry) || !NFS_FH(d_inode(dentry))->size)
+		return false;
+	return true;
+}
+
 /*
  * Note: RFC 1813 doesn't limit the number of auth flavors that
  * a server can return, so make something up.

fs/nfs/namespace.c

@@ -301,7 +301,7 @@ int nfs_submount(struct fs_context *fc, struct nfs_server *server)
 	int err;
 
 	/* Look it up again to get its attributes */
-	err = server->nfs_client->rpc_ops->lookup(d_inode(parent), &dentry->d_name,
+	err = server->nfs_client->rpc_ops->lookup(d_inode(parent), dentry,
 						  ctx->mntfh, ctx->clone_data.fattr,
 						  NULL);
 	dput(parent);

fs/nfs/nfs3proc.c

@@ -154,14 +154,14 @@ nfs3_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
 }
 
 static int
-nfs3_proc_lookup(struct inode *dir, const struct qstr *name,
+nfs3_proc_lookup(struct inode *dir, struct dentry *dentry,
 		 struct nfs_fh *fhandle, struct nfs_fattr *fattr,
 		 struct nfs4_label *label)
 {
 	struct nfs3_diropargs	arg = {
 		.fh		= NFS_FH(dir),
-		.name		= name->name,
-		.len		= name->len
+		.name		= dentry->d_name.name,
+		.len		= dentry->d_name.len
 	};
 	struct nfs3_diropres	res = {
 		.fh		= fhandle,
@@ -173,20 +173,25 @@ nfs3_proc_lookup(struct inode *dir, const struct qstr *name,
 		.rpc_resp	= &res,
 	};
 	int			status;
+	unsigned short task_flags = 0;
 
+	/* Is this is an attribute revalidation, subject to softreval? */
+	if (nfs_lookup_is_soft_revalidate(dentry))
+		task_flags |= RPC_TASK_TIMEOUT;
+
+	dprintk("NFS call  lookup %pd2\n", dentry);
 	res.dir_attr = nfs_alloc_fattr();
 	if (res.dir_attr == NULL)
 		return -ENOMEM;
 
-	dprintk("NFS call  lookup %s\n", name->name);
 	nfs_fattr_init(fattr);
-	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
+	status = rpc_call_sync(NFS_CLIENT(dir), &msg, task_flags);
 	nfs_refresh_inode(dir, res.dir_attr);
 	if (status >= 0 && !(fattr->valid & NFS_ATTR_FATTR)) {
 		msg.rpc_proc = &nfs3_procedures[NFS3PROC_GETATTR];
 		msg.rpc_argp = fhandle;
 		msg.rpc_resp = fattr;
-		status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
+		status = rpc_call_sync(NFS_CLIENT(dir), &msg, task_flags);
 	}
 	nfs_free_fattr(res.dir_attr);
 	dprintk("NFS reply lookup: %d\n", status);

fs/nfs/nfs4_fs.h

@@ -302,8 +302,10 @@ extern int nfs4_proc_fs_locations(struct rpc_clnt *, struct inode *, const struc
 extern int nfs4_proc_get_locations(struct inode *, struct nfs4_fs_locations *,
 		struct page *page, const struct cred *);
 extern int nfs4_proc_fsid_present(struct inode *, const struct cred *);
-extern struct rpc_clnt *nfs4_proc_lookup_mountpoint(struct inode *, const struct qstr *,
-			    struct nfs_fh *, struct nfs_fattr *);
+extern struct rpc_clnt *nfs4_proc_lookup_mountpoint(struct inode *,
+						    struct dentry *,
+						    struct nfs_fh *,
+						    struct nfs_fattr *);
 extern int nfs4_proc_secinfo(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *);
 extern const struct xattr_handler *nfs4_xattr_handlers[];
 extern int nfs4_set_rw_stateid(nfs4_stateid *stateid,

fs/nfs/nfs4namespace.c

@@ -442,12 +442,11 @@ int nfs4_submount(struct fs_context *fc, struct nfs_server *server)
 	struct dentry *dentry = ctx->clone_data.dentry;
 	struct dentry *parent = dget_parent(dentry);
 	struct inode *dir = d_inode(parent);
-	const struct qstr *name = &dentry->d_name;
 	struct rpc_clnt *client;
 	int ret;
 
 	/* Look it up again to get its attributes and sec flavor */
-	client = nfs4_proc_lookup_mountpoint(dir, name, ctx->mntfh,
+	client = nfs4_proc_lookup_mountpoint(dir, dentry, ctx->mntfh,
 					     ctx->clone_data.fattr);
 	dput(parent);
 	if (IS_ERR(client))

fs/nfs/nfs4proc.c

@@ -4177,7 +4177,7 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
 }
 
 static int _nfs4_proc_lookup(struct rpc_clnt *clnt, struct inode *dir,
-		const struct qstr *name, struct nfs_fh *fhandle,
+		struct dentry *dentry, struct nfs_fh *fhandle,
 		struct nfs_fattr *fattr, struct nfs4_label *label)
 {
 	struct nfs_server *server = NFS_SERVER(dir);
@@ -4185,7 +4185,7 @@ static int _nfs4_proc_lookup(struct rpc_clnt *clnt, struct inode *dir,
 	struct nfs4_lookup_arg args = {
 		.bitmask = server->attr_bitmask,
 		.dir_fh = NFS_FH(dir),
-		.name = name,
+		.name = &dentry->d_name,
 	};
 	struct nfs4_lookup_res res = {
 		.server = server,
@@ -4198,13 +4198,20 @@ static int _nfs4_proc_lookup(struct rpc_clnt *clnt, struct inode *dir,
 		.rpc_argp = &args,
 		.rpc_resp = &res,
 	};
+	unsigned short task_flags = 0;
+
+	/* Is this is an attribute revalidation, subject to softreval? */
+	if (nfs_lookup_is_soft_revalidate(dentry))
+		task_flags |= RPC_TASK_TIMEOUT;
 
 	args.bitmask = nfs4_bitmask(server, label);
 
 	nfs_fattr_init(fattr);
 
-	dprintk("NFS call  lookup %s\n", name->name);
-	status = nfs4_call_sync(clnt, server, &msg, &args.seq_args, &res.seq_res, 0);
+	dprintk("NFS call  lookup %pd2\n", dentry);
+	nfs4_init_sequence(&args.seq_args, &res.seq_res, 0, 0);
+	status = nfs4_do_call_sync(clnt, server, &msg,
+			&args.seq_args, &res.seq_res, task_flags);
 	dprintk("NFS reply lookup: %d\n", status);
 	return status;
 }
@@ -4218,16 +4225,17 @@ static void nfs_fixup_secinfo_attributes(struct nfs_fattr *fattr)
 }
 
 static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
-				   const struct qstr *name, struct nfs_fh *fhandle,
+				   struct dentry *dentry, struct nfs_fh *fhandle,
 				   struct nfs_fattr *fattr, struct nfs4_label *label)
 {
 	struct nfs4_exception exception = {
 		.interruptible = true,
 	};
 	struct rpc_clnt *client = *clnt;
+	const struct qstr *name = &dentry->d_name;
 	int err;
 	do {
-		err = _nfs4_proc_lookup(client, dir, name, fhandle, fattr, label);
+		err = _nfs4_proc_lookup(client, dir, dentry, fhandle, fattr, label);
 		trace_nfs4_lookup(dir, name, err);
 		switch (err) {
 		case -NFS4ERR_BADNAME:
@@ -4262,14 +4270,14 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
 	return err;
 }
 
-static int nfs4_proc_lookup(struct inode *dir, const struct qstr *name,
+static int nfs4_proc_lookup(struct inode *dir, struct dentry *dentry,
 			    struct nfs_fh *fhandle, struct nfs_fattr *fattr,
 			    struct nfs4_label *label)
 {
 	int status;
 	struct rpc_clnt *client = NFS_CLIENT(dir);
 
-	status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr, label);
+	status = nfs4_proc_lookup_common(&client, dir, dentry, fhandle, fattr, label);
 	if (client != NFS_CLIENT(dir)) {
 		rpc_shutdown_client(client);
 		nfs_fixup_secinfo_attributes(fattr);
@@ -4278,13 +4286,13 @@ static int nfs4_proc_lookup(struct inode *dir, const struct qstr *name,
 }
 
 struct rpc_clnt *
-nfs4_proc_lookup_mountpoint(struct inode *dir, const struct qstr *name,
+nfs4_proc_lookup_mountpoint(struct inode *dir, struct dentry *dentry,
 			    struct nfs_fh *fhandle, struct nfs_fattr *fattr)
 {
 	struct rpc_clnt *client = NFS_CLIENT(dir);
 	int status;
 
-	status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr, NULL);
+	status = nfs4_proc_lookup_common(&client, dir, dentry, fhandle, fattr, NULL);
 	if (status < 0)
 		return ERR_PTR(status);
 	return (client == NFS_CLIENT(dir)) ? rpc_clone_client(client) : client;

fs/nfs/proc.c

@@ -152,14 +152,14 @@ nfs_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
 }
 
 static int
-nfs_proc_lookup(struct inode *dir, const struct qstr *name,
+nfs_proc_lookup(struct inode *dir, struct dentry *dentry,
 		struct nfs_fh *fhandle, struct nfs_fattr *fattr,
 		struct nfs4_label *label)
 {
 	struct nfs_diropargs	arg = {
 		.fh		= NFS_FH(dir),
-		.name		= name->name,
-		.len		= name->len
+		.name		= dentry->d_name.name,
+		.len		= dentry->d_name.len
 	};
 	struct nfs_diropok	res = {
 		.fh		= fhandle,
@@ -171,10 +171,15 @@ nfs_proc_lookup(struct inode *dir, const struct qstr *name,
 		.rpc_resp	= &res,
 	};
 	int			status;
+	unsigned short task_flags = 0;
 
-	dprintk("NFS call  lookup %s\n", name->name);
+	/* Is this is an attribute revalidation, subject to softreval? */
+	if (nfs_lookup_is_soft_revalidate(dentry))
+		task_flags |= RPC_TASK_TIMEOUT;
+
+	dprintk("NFS call  lookup %pd2\n", dentry);
 	nfs_fattr_init(fattr);
-	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
+	status = rpc_call_sync(NFS_CLIENT(dir), &msg, task_flags);
 	dprintk("NFS reply lookup: %d\n", status);
 	return status;
 }

include/linux/nfs_xdr.h

@@ -1661,7 +1661,7 @@ struct nfs_rpc_ops {
 			    struct inode *);
 	int	(*setattr) (struct dentry *, struct nfs_fattr *,
 			    struct iattr *);
-	int	(*lookup)  (struct inode *, const struct qstr *,
+	int	(*lookup)  (struct inode *, struct dentry *,
 			    struct nfs_fh *, struct nfs_fattr *,
 			    struct nfs4_label *);
 	int	(*lookupp) (struct inode *, struct nfs_fh *,