NFS client bugfixes for Linux 3.4

Highlights include:
 - Fix NFSv4 infinite loops on open(O_TRUNC)
 - Fix an Oops and an infinite loop in the NFSv4 flock code
 - Don't register the PipeFS filesystem until it has been set up
 - Fix an Oops in nfs_try_to_update_request
 - Don't reuse NFSv4 open owners: fixes a bad sequence id storm.
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Merge tag 'nfs-for-3.4-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:
 - Fix NFSv4 infinite loops on open(O_TRUNC)
 - Fix an Oops and an infinite loop in the NFSv4 flock code
 - Don't register the PipeFS filesystem until it has been set up
 - Fix an Oops in nfs_try_to_update_request
 - Don't reuse NFSv4 open owners: fixes a bad sequence id storm.

* tag 'nfs-for-3.4-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv4: Keep dropped state owners on the LRU list for a while
  NFSv4: Ensure that we don't drop a state owner more than once
  NFSv4: Ensure we do not reuse open owner names
  nfs: Enclose hostname in brackets when needed in nfs_do_root_mount
  NFS: put open context on error in nfs_flush_multi
  NFS: put open context on error in nfs_pagein_multi
  NFSv4: Fix open(O_TRUNC) and ftruncate() error handling
  NFSv4: Ensure that we check lock exclusive/shared type against open modes
  NFSv4: Ensure that the LOCK code sets exception->inode
  NFS: check for req==NULL in nfs_try_to_update_request cleanup
  SUNRPC: register PipeFS file system after pernet sybsystem

fs/nfs/dir.c

@@ -1429,7 +1429,7 @@ static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry
 	}
 
 	open_flags = nd->intent.open.flags;
-	attr.ia_valid = 0;
+	attr.ia_valid = ATTR_OPEN;
 
 	ctx = create_nfs_open_context(dentry, open_flags);
 	res = ERR_CAST(ctx);
@@ -1536,7 +1536,7 @@ static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
 	if (IS_ERR(ctx))
 		goto out;
 
-	attr.ia_valid = 0;
+	attr.ia_valid = ATTR_OPEN;
 	if (openflags & O_TRUNC) {
 		attr.ia_valid |= ATTR_SIZE;
 		attr.ia_size = 0;

fs/nfs/nfs4_fs.h

@@ -59,6 +59,7 @@ struct nfs_unique_id {
 
 #define NFS_SEQID_CONFIRMED 1
 struct nfs_seqid_counter {
+	ktime_t create_time;
 	int owner_id;
 	int flags;
 	u32 counter;

fs/nfs/nfs4proc.c

@@ -838,7 +838,8 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	p->o_arg.open_flags = flags;
 	p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
 	p->o_arg.clientid = server->nfs_client->cl_clientid;
-	p->o_arg.id = sp->so_seqid.owner_id;
+	p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
+	p->o_arg.id.uniquifier = sp->so_seqid.owner_id;
 	p->o_arg.name = &dentry->d_name;
 	p->o_arg.server = server;
 	p->o_arg.bitmask = server->attr_bitmask;
@@ -1466,8 +1467,7 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
 			goto unlock_no_action;
 		rcu_read_unlock();
 	}
-	/* Update sequence id. */
-	data->o_arg.id = sp->so_seqid.owner_id;
+	/* Update client id. */
 	data->o_arg.clientid = sp->so_server->nfs_client->cl_clientid;
 	if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS) {
 		task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR];
@@ -1954,10 +1954,19 @@ static int nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
 	};
 	int err;
 	do {
-		err = nfs4_handle_exception(server,
-				_nfs4_do_setattr(inode, cred, fattr, sattr, state),
-				&exception);
+		err = _nfs4_do_setattr(inode, cred, fattr, sattr, state);
+		switch (err) {
+		case -NFS4ERR_OPENMODE:
+			if (state && !(state->state & FMODE_WRITE)) {
+				err = -EBADF;
+				if (sattr->ia_valid & ATTR_OPEN)
+					err = -EACCES;
+				goto out;
+			}
+		}
+		err = nfs4_handle_exception(server, err, &exception);
 	} while (exception.retry);
+out:
 	return err;
 }
 
@@ -4558,7 +4567,9 @@ static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *f
 static int nfs4_lock_reclaim(struct nfs4_state *state, struct file_lock *request)
 {
 	struct nfs_server *server = NFS_SERVER(state->inode);
-	struct nfs4_exception exception = { };
+	struct nfs4_exception exception = {
+		.inode = state->inode,
+	};
 	int err;
 
 	do {
@@ -4576,7 +4587,9 @@ static int nfs4_lock_reclaim(struct nfs4_state *state, struct file_lock *request
 static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request)
 {
 	struct nfs_server *server = NFS_SERVER(state->inode);
-	struct nfs4_exception exception = { };
+	struct nfs4_exception exception = {
+		.inode = state->inode,
+	};
 	int err;
 
 	err = nfs4_set_lock_state(state, request);
@@ -4676,6 +4689,7 @@ static int nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *
 {
 	struct nfs4_exception exception = {
 		.state = state,
+		.inode = state->inode,
 	};
 	int err;
 
@@ -4721,6 +4735,20 @@ nfs4_proc_lock(struct file *filp, int cmd, struct file_lock *request)
 
 	if (state == NULL)
 		return -ENOLCK;
+	/*
+	 * Don't rely on the VFS having checked the file open mode,
+	 * since it won't do this for flock() locks.
+	 */
+	switch (request->fl_type & (F_RDLCK|F_WRLCK|F_UNLCK)) {
+	case F_RDLCK:
+		if (!(filp->f_mode & FMODE_READ))
+			return -EBADF;
+		break;
+	case F_WRLCK:
+		if (!(filp->f_mode & FMODE_WRITE))
+			return -EBADF;
+	}
+
 	do {
 		status = nfs4_proc_setlk(state, cmd, request);
 		if ((status != -EAGAIN) || IS_SETLK(cmd))

fs/nfs/nfs4state.c

@@ -393,6 +393,7 @@ nfs4_remove_state_owner_locked(struct nfs4_state_owner *sp)
 static void
 nfs4_init_seqid_counter(struct nfs_seqid_counter *sc)
 {
+	sc->create_time = ktime_get();
 	sc->flags = 0;
 	sc->counter = 0;
 	spin_lock_init(&sc->lock);
@@ -434,13 +435,17 @@ nfs4_alloc_state_owner(struct nfs_server *server,
 static void
 nfs4_drop_state_owner(struct nfs4_state_owner *sp)
 {
-	if (!RB_EMPTY_NODE(&sp->so_server_node)) {
+	struct rb_node *rb_node = &sp->so_server_node;
+
+	if (!RB_EMPTY_NODE(rb_node)) {
 		struct nfs_server *server = sp->so_server;
 		struct nfs_client *clp = server->nfs_client;
 
 		spin_lock(&clp->cl_lock);
-		rb_erase(&sp->so_server_node, &server->state_owners);
-		RB_CLEAR_NODE(&sp->so_server_node);
+		if (!RB_EMPTY_NODE(rb_node)) {
+			rb_erase(rb_node, &server->state_owners);
+			RB_CLEAR_NODE(rb_node);
+		}
 		spin_unlock(&clp->cl_lock);
 	}
 }
@@ -516,6 +521,14 @@ struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *server,
 /**
  * nfs4_put_state_owner - Release a nfs4_state_owner
  * @sp: state owner data to release
+ *
+ * Note that we keep released state owners on an LRU
+ * list.
+ * This caches valid state owners so that they can be
+ * reused, to avoid the OPEN_CONFIRM on minor version 0.
+ * It also pins the uniquifier of dropped state owners for
+ * a while, to ensure that those state owner names are
+ * never reused.
  */
 void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 {
@@ -525,15 +538,9 @@ void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 	if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock))
 		return;
 
-	if (!RB_EMPTY_NODE(&sp->so_server_node)) {
-		sp->so_expires = jiffies;
-		list_add_tail(&sp->so_lru, &server->state_owners_lru);
-		spin_unlock(&clp->cl_lock);
-	} else {
-		nfs4_remove_state_owner_locked(sp);
-		spin_unlock(&clp->cl_lock);
-		nfs4_free_state_owner(sp);
-	}
+	sp->so_expires = jiffies;
+	list_add_tail(&sp->so_lru, &server->state_owners_lru);
+	spin_unlock(&clp->cl_lock);
 }
 
 /**

fs/nfs/nfs4xdr.c

@@ -74,7 +74,7 @@ static int nfs4_stat_to_errno(int);
 /* lock,open owner id:
  * we currently use size 2 (u64) out of (NFS4_OPAQUE_LIMIT  >> 2)
  */
-#define open_owner_id_maxsz	(1 + 1 + 4)
+#define open_owner_id_maxsz	(1 + 2 + 1 + 1 + 2)
 #define lock_owner_id_maxsz	(1 + 1 + 4)
 #define decode_lockowner_maxsz	(1 + XDR_QUADLEN(IDMAP_NAMESZ))
 #define compound_encode_hdr_maxsz	(3 + (NFS4_MAXTAGLEN >> 2))
@@ -1340,12 +1340,13 @@ static inline void encode_openhdr(struct xdr_stream *xdr, const struct nfs_opena
  */
 	encode_nfs4_seqid(xdr, arg->seqid);
 	encode_share_access(xdr, arg->fmode);
-	p = reserve_space(xdr, 32);
+	p = reserve_space(xdr, 36);
 	p = xdr_encode_hyper(p, arg->clientid);
-	*p++ = cpu_to_be32(20);
+	*p++ = cpu_to_be32(24);
 	p = xdr_encode_opaque_fixed(p, "open id:", 8);
 	*p++ = cpu_to_be32(arg->server->s_dev);
-	xdr_encode_hyper(p, arg->id);
+	*p++ = cpu_to_be32(arg->id.uniquifier);
+	xdr_encode_hyper(p, arg->id.create_time);
 }
 
 static inline void encode_createmode(struct xdr_stream *xdr, const struct nfs_openargs *arg)

fs/nfs/read.c

@@ -322,7 +322,7 @@ static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc, struct list_head
 	while (!list_empty(res)) {
 		data = list_entry(res->next, struct nfs_read_data, list);
 		list_del(&data->list);
-		nfs_readdata_free(data);
+		nfs_readdata_release(data);
 	}
 	nfs_readpage_release(req);
 	return -ENOMEM;

fs/nfs/super.c

@@ -2767,11 +2767,15 @@ static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
 	char *root_devname;
 	size_t len;
 
-	len = strlen(hostname) + 3;
+	len = strlen(hostname) + 5;
 	root_devname = kmalloc(len, GFP_KERNEL);
 	if (root_devname == NULL)
 		return ERR_PTR(-ENOMEM);
-	snprintf(root_devname, len, "%s:/", hostname);
+	/* Does hostname needs to be enclosed in brackets? */
+	if (strchr(hostname, ':'))
+		snprintf(root_devname, len, "[%s]:/", hostname);
+	else
+		snprintf(root_devname, len, "%s:/", hostname);
 	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
 	kfree(root_devname);
 	return root_mnt;

fs/nfs/write.c

@@ -682,7 +682,8 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 		req->wb_bytes = rqend - req->wb_offset;
 out_unlock:
 	spin_unlock(&inode->i_lock);
-	nfs_clear_request_commit(req);
+	if (req)
+		nfs_clear_request_commit(req);
 	return req;
 out_flushme:
 	spin_unlock(&inode->i_lock);
@@ -1018,7 +1019,7 @@ static int nfs_flush_multi(struct nfs_pageio_descriptor *desc, struct list_head
 	while (!list_empty(res)) {
 		data = list_entry(res->next, struct nfs_write_data, list);
 		list_del(&data->list);
-		nfs_writedata_free(data);
+		nfs_writedata_release(data);
 	}
 	nfs_redirty_request(req);
 	return -ENOMEM;

include/linux/nfs_xdr.h

@@ -312,6 +312,11 @@ struct nfs4_layoutreturn {
 	int rpc_status;
 };
 
+struct stateowner_id {
+	__u64	create_time;
+	__u32	uniquifier;
+};
+
 /*
  * Arguments to the open call.
  */
@@ -321,7 +326,7 @@ struct nfs_openargs {
 	int			open_flags;
 	fmode_t			fmode;
 	__u64                   clientid;
-	__u64                   id;
+	struct stateowner_id	id;
 	union {
 		struct {
 			struct iattr *  attrs;    /* UNCHECKED, GUARDED */

net/sunrpc/sunrpc_syms.c

@@ -75,19 +75,20 @@ static struct pernet_operations sunrpc_net_ops = {
 static int __init
 init_sunrpc(void)
 {
-	int err = register_rpc_pipefs();
+	int err = rpc_init_mempool();
 	if (err)
 		goto out;
-	err = rpc_init_mempool();
-	if (err)
-		goto out2;
 	err = rpcauth_init_module();
 	if (err)
-		goto out3;
+		goto out2;
 
 	cache_initialize();
 
 	err = register_pernet_subsys(&sunrpc_net_ops);
+	if (err)
+		goto out3;
+
+	err = register_rpc_pipefs();
 	if (err)
 		goto out4;
 #ifdef RPC_DEBUG
@@ -98,11 +99,11 @@ init_sunrpc(void)
 	return 0;
 
 out4:
-	rpcauth_remove_module();
+	unregister_pernet_subsys(&sunrpc_net_ops);
 out3:
-	rpc_destroy_mempool();
+	rpcauth_remove_module();
 out2:
-	unregister_rpc_pipefs();
+	rpc_destroy_mempool();
 out:
 	return err;
 }