[mirror_ubuntu-artful-kernel.git] / fs / nfs / namespace.c

/*
 * linux/fs/nfs/namespace.c
 *
 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
 * - Modified by David Howells <dhowells@redhat.com>
 *
 * NFS namespace
 */

#include <linux/dcache.h>
#include <linux/gfp.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/nfs_fs.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
#include <linux/sunrpc/gss_api.h>
#include "internal.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

static void nfs_expire_automounts(struct work_struct *work);

static LIST_HEAD(nfs_automount_list);
static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
int nfs_mountpoint_expiry_timeout = 500 * HZ;

static struct vfsmount *nfs_do_submount(struct dentry *dentry,
					struct nfs_fh *fh,
					struct nfs_fattr *fattr,
					rpc_authflavor_t authflavor);

/*
 * nfs_path - reconstruct the path given an arbitrary dentry
 * @base - used to return pointer to the end of devname part of path
 * @dentry - pointer to dentry
 * @buffer - result buffer
 * @buflen - length of buffer
 *
 * Helper function for constructing the server pathname
 * by arbitrary hashed dentry.
 *
 * This is mainly for use in figuring out the path on the
 * server side when automounting on top of an existing partition
 * and in generating /proc/mounts and friends.
 */
char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen)
{
	char *end;
	int namelen;
	unsigned seq;
	const char *base;

rename_retry:
	end = buffer+buflen;
	*--end = '\0';
	buflen--;

	seq = read_seqbegin(&rename_lock);
	rcu_read_lock();
	while (1) {
		spin_lock(&dentry->d_lock);
		if (IS_ROOT(dentry))
			break;
		namelen = dentry->d_name.len;
		buflen -= namelen + 1;
		if (buflen < 0)
			goto Elong_unlock;
		end -= namelen;
		memcpy(end, dentry->d_name.name, namelen);
		*--end = '/';
		spin_unlock(&dentry->d_lock);
		dentry = dentry->d_parent;
	}
	if (read_seqretry(&rename_lock, seq)) {
		spin_unlock(&dentry->d_lock);
		rcu_read_unlock();
		goto rename_retry;
	}
	if (*end != '/') {
		if (--buflen < 0) {
			spin_unlock(&dentry->d_lock);
			rcu_read_unlock();
			goto Elong;
		}
		*--end = '/';
	}
	*p = end;
	base = dentry->d_fsdata;
	if (!base) {
		spin_unlock(&dentry->d_lock);
		rcu_read_unlock();
		WARN_ON(1);
		return end;
	}
	namelen = strlen(base);
	/* Strip off excess slashes in base string */
	while (namelen > 0 && base[namelen - 1] == '/')
		namelen--;
	buflen -= namelen;
	if (buflen < 0) {
		spin_unlock(&dentry->d_lock);
		rcu_read_unlock();
		goto Elong;
	}
	end -= namelen;
	memcpy(end, base, namelen);
	spin_unlock(&dentry->d_lock);
	rcu_read_unlock();
	return end;
Elong_unlock:
	spin_unlock(&dentry->d_lock);
	rcu_read_unlock();
	if (read_seqretry(&rename_lock, seq))
		goto rename_retry;
Elong:
	return ERR_PTR(-ENAMETOOLONG);
}

#ifdef CONFIG_NFS_V4
rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
{
	struct gss_api_mech *mech;
	struct xdr_netobj oid;
	int i;
	rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX;

	for (i = 0; i < flavors->num_flavors; i++) {
		struct nfs4_secinfo_flavor *flavor;
		flavor = &flavors->flavors[i];

		if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) {
			pseudoflavor = flavor->flavor;
			break;
		} else if (flavor->flavor == RPC_AUTH_GSS) {
			oid.len  = flavor->gss.sec_oid4.len;
			oid.data = flavor->gss.sec_oid4.data;
			mech = gss_mech_get_by_OID(&oid);
			if (!mech)
				continue;
			pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service);
			gss_mech_put(mech);
			break;
		}
	}

	return pseudoflavor;
}

static int nfs_negotiate_security(const struct dentry *parent,
				  const struct dentry *dentry,
				  rpc_authflavor_t *flavor)
{
	struct page *page;
	struct nfs4_secinfo_flavors *flavors;
	int (*secinfo)(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *);
	int ret = -EPERM;

	secinfo = NFS_PROTO(parent->d_inode)->secinfo;
	if (secinfo != NULL) {
		page = alloc_page(GFP_KERNEL);
		if (!page) {
			ret = -ENOMEM;
			goto out;
		}
		flavors = page_address(page);
		ret = secinfo(parent->d_inode, &dentry->d_name, flavors);
		*flavor = nfs_find_best_sec(flavors);
		put_page(page);
	}

out:
	return ret;
}

static int nfs_lookup_with_sec(struct nfs_server *server, struct dentry *parent,
			       struct dentry *dentry, struct path *path,
			       struct nfs_fh *fh, struct nfs_fattr *fattr,
			       rpc_authflavor_t *flavor)
{
	struct rpc_clnt *clone;
	struct rpc_auth *auth;
	int err;

	err = nfs_negotiate_security(parent, path->dentry, flavor);
	if (err < 0)
		goto out;
	clone  = rpc_clone_client(server->client);
	auth   = rpcauth_create(*flavor, clone);
	if (!auth) {
		err = -EIO;
		goto out_shutdown;
	}
	err = server->nfs_client->rpc_ops->lookup(clone, parent->d_inode,
						  &path->dentry->d_name,
						  fh, fattr);
out_shutdown:
	rpc_shutdown_client(clone);
out:
	return err;
}

static struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir,
					      struct qstr *name,
					      struct nfs_fh *fh,
					      struct nfs_fattr *fattr)
{
	int err;

	if (NFS_PROTO(dir)->version == 4)
		return nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);

	err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
	if (err)
		return ERR_PTR(err);
	return rpc_clone_client(NFS_SERVER(dir)->client);
}
#else /* CONFIG_NFS_V4 */
static inline int nfs_lookup_with_sec(struct nfs_server *server,
				      struct dentry *parent, struct dentry *dentry,
				      struct path *path, struct nfs_fh *fh,
				      struct nfs_fattr *fattr,
				      rpc_authflavor_t *flavor)
{
	return -EPERM;
}

static inline struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir,
						     struct qstr *name,
						     struct nfs_fh *fh,
						     struct nfs_fattr *fattr)
{
	int err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
	if (err)
		return ERR_PTR(err);
	return rpc_clone_client(NFS_SERVER(dir)->client);
}
#endif /* CONFIG_NFS_V4 */

/*
 * nfs_d_automount - Handle crossing a mountpoint on the server
 * @path - The mountpoint
 *
 * When we encounter a mountpoint on the server, we want to set up
 * a mountpoint on the client too, to prevent inode numbers from
 * colliding, and to allow "df" to work properly.
 * On NFSv4, we also want to allow for the fact that different
 * filesystems may be migrated to different servers in a failover
 * situation, and that different filesystems may want to use
 * different security flavours.
 */
struct vfsmount *nfs_d_automount(struct path *path)
{
	struct vfsmount *mnt;
	struct dentry *parent;
	struct nfs_fh *fh = NULL;
	struct nfs_fattr *fattr = NULL;
	struct rpc_clnt *client;
	rpc_authflavor_t flavor = RPC_AUTH_UNIX;

	dprintk("--> nfs_d_automount()\n");

	mnt = ERR_PTR(-ESTALE);
	if (IS_ROOT(path->dentry))
		goto out_nofree;

	mnt = ERR_PTR(-ENOMEM);
	fh = nfs_alloc_fhandle();
	fattr = nfs_alloc_fattr();
	if (fh == NULL || fattr == NULL)
		goto out;

	dprintk("%s: enter\n", __func__);

	/* Look it up again to get its attributes */
	parent = dget_parent(path->dentry);
	client = nfs_lookup_mountpoint(parent->d_inode, &path->dentry->d_name, fh, fattr);
	dput(parent);
	if (IS_ERR(client)) {
		mnt = ERR_CAST(client);
		goto out;
	}

	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
		mnt = nfs_do_refmount(client, path->dentry);
	else
		mnt = nfs_do_submount(path->dentry, fh, fattr, flavor);
	rpc_shutdown_client(client);

	if (IS_ERR(mnt))
		goto out;

	dprintk("%s: done, success\n", __func__);
	mntget(mnt); /* prevent immediate expiration */
	mnt_set_expiry(mnt, &nfs_automount_list);
	schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);

out:
	nfs_free_fattr(fattr);
	nfs_free_fhandle(fh);
out_nofree:
	if (IS_ERR(mnt))
		dprintk("<-- %s(): error %ld\n", __func__, PTR_ERR(mnt));
	else
		dprintk("<-- %s() = %p\n", __func__, mnt);
	return mnt;
}

const struct inode_operations nfs_mountpoint_inode_operations = {
	.getattr	= nfs_getattr,
};

const struct inode_operations nfs_referral_inode_operations = {
};

static void nfs_expire_automounts(struct work_struct *work)
{
	struct list_head *list = &nfs_automount_list;

	mark_mounts_for_expiry(list);
	if (!list_empty(list))
		schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
}

void nfs_release_automount_timer(void)
{
	if (list_empty(&nfs_automount_list))
		cancel_delayed_work(&nfs_automount_task);
}

/*
 * Clone a mountpoint of the appropriate type
 */
static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
					   const char *devname,
					   struct nfs_clone_mount *mountdata)
{
#ifdef CONFIG_NFS_V4
	struct vfsmount *mnt = ERR_PTR(-EINVAL);
	switch (server->nfs_client->rpc_ops->version) {
		case 2:
		case 3:
			mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
			break;
		case 4:
			mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata);
	}
	return mnt;
#else
	return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
#endif
}

/**
 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
 * @dentry - parent directory
 * @fh - filehandle for new root dentry
 * @fattr - attributes for new root inode
 * @authflavor - security flavor to use when performing the mount
 *
 */
static struct vfsmount *nfs_do_submount(struct dentry *dentry,
					struct nfs_fh *fh,
					struct nfs_fattr *fattr,
					rpc_authflavor_t authflavor)
{
	struct nfs_clone_mount mountdata = {
		.sb = dentry->d_sb,
		.dentry = dentry,
		.fh = fh,
		.fattr = fattr,
		.authflavor = authflavor,
	};
	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
	char *page = (char *) __get_free_page(GFP_USER);
	char *devname;

	dprintk("--> nfs_do_submount()\n");

	dprintk("%s: submounting on %s/%s\n", __func__,
			dentry->d_parent->d_name.name,
			dentry->d_name.name);
	if (page == NULL)
		goto out;
	devname = nfs_devname(dentry, page, PAGE_SIZE);
	mnt = (struct vfsmount *)devname;
	if (IS_ERR(devname))
		goto free_page;
	mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
free_page:
	free_page((unsigned long)page);
out:
	dprintk("%s: done\n", __func__);

	dprintk("<-- nfs_do_submount() = %p\n", mnt);
	return mnt;
}
Commit	Line	Data
55a97593 TM	1	/*
	2	* linux/fs/nfs/namespace.c
	3	*
	4	* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
54ceac45	5	* - Modified by David Howells <dhowells@redhat.com>
55a97593 TM	6	*
	7	* NFS namespace
	8	*/
	9
55a97593	10	#include <linux/dcache.h>
5a0e3ad6	11	#include <linux/gfp.h>
55a97593 TM	12	#include <linux/mount.h>
	13	#include <linux/namei.h>
	14	#include <linux/nfs_fs.h>
	15	#include <linux/string.h>
	16	#include <linux/sunrpc/clnt.h>
	17	#include <linux/vfs.h>
7ebb9315	18	#include <linux/sunrpc/gss_api.h>
f7b422b1	19	#include "internal.h"
55a97593 TM	20
	21	#define NFSDBG_FACILITY NFSDBG_VFS
	22
65f27f38	23	static void nfs_expire_automounts(struct work_struct *work);
f7b422b1	24
a3dab293	25	static LIST_HEAD(nfs_automount_list);
65f27f38	26	static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
51d8fa6a TM	27	int nfs_mountpoint_expiry_timeout = 500 * HZ;
51d8fa6a TM	28
f8ad9c4b	29	static struct vfsmount nfs_do_submount(struct dentry dentry,
66f37509	30	struct nfs_fh *fh,
7ebb9315 BS	31	struct nfs_fattr *fattr,
7ebb9315 BS	32	rpc_authflavor_t authflavor);
66f37509	33
f7b422b1 DH	34	/*
f7b422b1 DH	35	* nfs_path - reconstruct the path given an arbitrary dentry
b514f872	36	* @base - used to return pointer to the end of devname part of path
f7b422b1 DH	37	* @dentry - pointer to dentry
	38	* @buffer - result buffer
	39	* @buflen - length of buffer
	40	*
b514f872 AV	41	* Helper function for constructing the server pathname
b514f872 AV	42	* by arbitrary hashed dentry.
f7b422b1 DH	43	*
f7b422b1 DH	44	* This is mainly for use in figuring out the path on the
b514f872 AV	45	* server side when automounting on top of an existing partition
b514f872 AV	46	* and in generating /proc/mounts and friends.
f7b422b1	47	*/
b514f872	48	char nfs_path(char p, struct dentry dentry, char *buffer, ssize_t buflen)
f7b422b1	49	{
949854d0	50	char *end;
f7b422b1	51	int namelen;
949854d0	52	unsigned seq;
b514f872	53	const char *base;
f7b422b1	54
949854d0 NP	55	rename_retry:
949854d0 NP	56	end = buffer+buflen;
f7b422b1 DH	57	*--end = '\0';
f7b422b1 DH	58	buflen--;
949854d0 NP	59
	60	seq = read_seqbegin(&rename_lock);
	61	rcu_read_lock();
b514f872 AV	62	while (1) {
	63	spin_lock(&dentry->d_lock);
	64	if (IS_ROOT(dentry))
	65	break;
f7b422b1 DH	66	namelen = dentry->d_name.len;
	67	buflen -= namelen + 1;
	68	if (buflen < 0)
ce510193	69	goto Elong_unlock;
f7b422b1 DH	70	end -= namelen;
	71	memcpy(end, dentry->d_name.name, namelen);
	72	*--end = '/';
b514f872	73	spin_unlock(&dentry->d_lock);
f7b422b1 DH	74	dentry = dentry->d_parent;
f7b422b1 DH	75	}
b514f872 AV	76	if (read_seqretry(&rename_lock, seq)) {
	77	spin_unlock(&dentry->d_lock);
	78	rcu_read_unlock();
949854d0	79	goto rename_retry;
b514f872	80	}
0b75b35c	81	if (*end != '/') {
b514f872 AV	82	if (--buflen < 0) {
	83	spin_unlock(&dentry->d_lock);
	84	rcu_read_unlock();
0b75b35c	85	goto Elong;
b514f872	86	}
0b75b35c TM	87	*--end = '/';
0b75b35c TM	88	}
b514f872 AV	89	*p = end;
	90	base = dentry->d_fsdata;
	91	if (!base) {
	92	spin_unlock(&dentry->d_lock);
	93	rcu_read_unlock();
	94	WARN_ON(1);
	95	return end;
	96	}
f7b422b1 DH	97	namelen = strlen(base);
	98	/* Strip off excess slashes in base string */
	99	while (namelen > 0 && base[namelen - 1] == '/')
	100	namelen--;
	101	buflen -= namelen;
b514f872	102	if (buflen < 0) {
1c34092a	103	spin_unlock(&dentry->d_lock);
b514f872	104	rcu_read_unlock();
f7b422b1	105	goto Elong;
b514f872	106	}
f7b422b1 DH	107	end -= namelen;
f7b422b1 DH	108	memcpy(end, base, namelen);
b514f872 AV	109	spin_unlock(&dentry->d_lock);
b514f872 AV	110	rcu_read_unlock();
f7b422b1	111	return end;
ce510193	112	Elong_unlock:
1c34092a	113	spin_unlock(&dentry->d_lock);
949854d0 NP	114	rcu_read_unlock();
	115	if (read_seqretry(&rename_lock, seq))
	116	goto rename_retry;
f7b422b1 DH	117	Elong:
	118	return ERR_PTR(-ENAMETOOLONG);
	119	}
	120
7ebb9315	121	#ifdef CONFIG_NFS_V4
fca78d6d	122	rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
7ebb9315 BS	123	{
	124	struct gss_api_mech *mech;
	125	struct xdr_netobj oid;
	126	int i;
	127	rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX;
	128
	129	for (i = 0; i < flavors->num_flavors; i++) {
	130	struct nfs4_secinfo_flavor *flavor;
	131	flavor = &flavors->flavors[i];
	132
	133	if (flavor->flavor == RPC_AUTH_NULL \|\| flavor->flavor == RPC_AUTH_UNIX) {
	134	pseudoflavor = flavor->flavor;
	135	break;
	136	} else if (flavor->flavor == RPC_AUTH_GSS) {
	137	oid.len = flavor->gss.sec_oid4.len;
	138	oid.data = flavor->gss.sec_oid4.data;
	139	mech = gss_mech_get_by_OID(&oid);
	140	if (!mech)
	141	continue;
	142	pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service);
	143	gss_mech_put(mech);
	144	break;
	145	}
	146	}
	147
	148	return pseudoflavor;
	149	}
	150
41887590 BS	151	static int nfs_negotiate_security(const struct dentry *parent,
	152	const struct dentry *dentry,
	153	rpc_authflavor_t *flavor)
7ebb9315	154	{
7ebb9315 BS	155	struct page *page;
	156	struct nfs4_secinfo_flavors *flavors;
	157	int (secinfo)(struct inode , const struct qstr , struct nfs4_secinfo_flavors );
41887590	158	int ret = -EPERM;
7ebb9315 BS	159
	160	secinfo = NFS_PROTO(parent->d_inode)->secinfo;
	161	if (secinfo != NULL) {
	162	page = alloc_page(GFP_KERNEL);
	163	if (!page) {
41887590	164	ret = -ENOMEM;
7ebb9315 BS	165	goto out;
	166	}
	167	flavors = page_address(page);
41887590	168	ret = secinfo(parent->d_inode, &dentry->d_name, flavors);
561f0b0a	169	*flavor = nfs_find_best_sec(flavors);
7ebb9315 BS	170	put_page(page);
	171	}
	172
7ebb9315	173	out:
41887590	174	return ret;
7ebb9315 BS	175	}
7ebb9315 BS	176
41887590 BS	177	static int nfs_lookup_with_sec(struct nfs_server server, struct dentry parent,
	178	struct dentry dentry, struct path path,
	179	struct nfs_fh fh, struct nfs_fattr fattr,
	180	rpc_authflavor_t *flavor)
7ebb9315	181	{
7ebb9315 BS	182	struct rpc_clnt *clone;
	183	struct rpc_auth *auth;
	184	int err;
	185
41887590 BS	186	err = nfs_negotiate_security(parent, path->dentry, flavor);
41887590 BS	187	if (err < 0)
7ebb9315 BS	188	goto out;
7ebb9315 BS	189	clone = rpc_clone_client(server->client);
41887590	190	auth = rpcauth_create(*flavor, clone);
7ebb9315	191	if (!auth) {
41887590	192	err = -EIO;
a0e7e3cf	193	goto out_shutdown;
7ebb9315 BS	194	}
	195	err = server->nfs_client->rpc_ops->lookup(clone, parent->d_inode,
	196	&path->dentry->d_name,
	197	fh, fattr);
a0e7e3cf TM	198	out_shutdown:
a0e7e3cf TM	199	rpc_shutdown_client(clone);
7ebb9315	200	out:
41887590	201	return err;
7ebb9315	202	}
f05d147f BS	203
	204	static struct rpc_clnt nfs_lookup_mountpoint(struct inode dir,
	205	struct qstr *name,
	206	struct nfs_fh *fh,
	207	struct nfs_fattr *fattr)
	208	{
	209	int err;
	210
	211	if (NFS_PROTO(dir)->version == 4)
	212	return nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
	213
	214	err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
	215	if (err)
	216	return ERR_PTR(err);
	217	return rpc_clone_client(NFS_SERVER(dir)->client);
	218	}
7ebb9315	219	#else /* CONFIG_NFS_V4 */
41887590 BS	220	static inline int nfs_lookup_with_sec(struct nfs_server *server,
	221	struct dentry parent, struct dentry dentry,
	222	struct path path, struct nfs_fh fh,
	223	struct nfs_fattr *fattr,
	224	rpc_authflavor_t *flavor)
7ebb9315 BS	225	{
	226	return -EPERM;
	227	}
f05d147f BS	228
	229	static inline struct rpc_clnt nfs_lookup_mountpoint(struct inode dir,
	230	struct qstr *name,
	231	struct nfs_fh *fh,
	232	struct nfs_fattr *fattr)
	233	{
	234	int err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
	235	if (err)
	236	return ERR_PTR(err);
	237	return rpc_clone_client(NFS_SERVER(dir)->client);
	238	}
7ebb9315 BS	239	#endif /* CONFIG_NFS_V4 */
7ebb9315 BS	240
55a97593	241	/*
36d43a43 DH	242	* nfs_d_automount - Handle crossing a mountpoint on the server
36d43a43 DH	243	* @path - The mountpoint
55a97593 TM	244	*
	245	* When we encounter a mountpoint on the server, we want to set up
	246	* a mountpoint on the client too, to prevent inode numbers from
	247	* colliding, and to allow "df" to work properly.
	248	* On NFSv4, we also want to allow for the fact that different
	249	* filesystems may be migrated to different servers in a failover
	250	* situation, and that different filesystems may want to use
	251	* different security flavours.
	252	*/
36d43a43	253	struct vfsmount nfs_d_automount(struct path path)
55a97593 TM	254	{
55a97593 TM	255	struct vfsmount *mnt;
55a97593	256	struct dentry *parent;
a4d7f168 TM	257	struct nfs_fh *fh = NULL;
a4d7f168 TM	258	struct nfs_fattr *fattr = NULL;
f05d147f	259	struct rpc_clnt *client;
41887590	260	rpc_authflavor_t flavor = RPC_AUTH_UNIX;
55a97593	261
36d43a43	262	dprintk("--> nfs_d_automount()\n");
54ceac45	263
36d43a43 DH	264	mnt = ERR_PTR(-ESTALE);
	265	if (IS_ROOT(path->dentry))
	266	goto out_nofree;
44d5759d	267
36d43a43	268	mnt = ERR_PTR(-ENOMEM);
a4d7f168 TM	269	fh = nfs_alloc_fhandle();
	270	fattr = nfs_alloc_fattr();
	271	if (fh == NULL \|\| fattr == NULL)
36d43a43	272	goto out;
a4d7f168	273
3110ff80	274	dprintk("%s: enter\n", __func__);
54ceac45	275
36d43a43 DH	276	/* Look it up again to get its attributes */
36d43a43 DH	277	parent = dget_parent(path->dentry);
f05d147f	278	client = nfs_lookup_mountpoint(parent->d_inode, &path->dentry->d_name, fh, fattr);
55a97593	279	dput(parent);
f05d147f BS	280	if (IS_ERR(client)) {
f05d147f BS	281	mnt = ERR_CAST(client);
36d43a43 DH	282	goto out;
36d43a43 DH	283	}
55a97593	284
a4d7f168	285	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
f05d147f	286	mnt = nfs_do_refmount(client, path->dentry);
6b97fd3d	287	else
7ebb9315	288	mnt = nfs_do_submount(path->dentry, fh, fattr, flavor);
f05d147f BS	289	rpc_shutdown_client(client);
f05d147f BS	290
55a97593	291	if (IS_ERR(mnt))
36d43a43	292	goto out;
55a97593	293
ea5b778a DH	294	dprintk("%s: done, success\n", __func__);
	295	mntget(mnt); /* prevent immediate expiration */
	296	mnt_set_expiry(mnt, &nfs_automount_list);
	297	schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
36d43a43	298
55a97593	299	out:
a4d7f168 TM	300	nfs_free_fattr(fattr);
a4d7f168 TM	301	nfs_free_fhandle(fh);
36d43a43	302	out_nofree:
d7c32675 CL	303	if (IS_ERR(mnt))
	304	dprintk("<-- %s(): error %ld\n", __func__, PTR_ERR(mnt));
	305	else
	306	dprintk("<-- %s() = %p\n", __func__, mnt);
36d43a43	307	return mnt;
55a97593 TM	308	}
55a97593 TM	309
92e1d5be	310	const struct inode_operations nfs_mountpoint_inode_operations = {
55a97593 TM	311	.getattr = nfs_getattr,
55a97593 TM	312	};
51d8fa6a	313
92e1d5be	314	const struct inode_operations nfs_referral_inode_operations = {
6b97fd3d MN	315	};
6b97fd3d MN	316
65f27f38	317	static void nfs_expire_automounts(struct work_struct *work)
51d8fa6a	318	{
65f27f38	319	struct list_head *list = &nfs_automount_list;
51d8fa6a TM	320
	321	mark_mounts_for_expiry(list);
	322	if (!list_empty(list))
	323	schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
	324	}
	325
	326	void nfs_release_automount_timer(void)
	327	{
3d39c691	328	if (list_empty(&nfs_automount_list))
560aef74	329	cancel_delayed_work(&nfs_automount_task);
51d8fa6a	330	}
f7b422b1 DH	331
	332	/*
	333	* Clone a mountpoint of the appropriate type
	334	*/
509de811 DH	335	static struct vfsmount nfs_do_clone_mount(struct nfs_server server,
509de811 DH	336	const char *devname,
f7b422b1 DH	337	struct nfs_clone_mount *mountdata)
	338	{
	339	#ifdef CONFIG_NFS_V4
fd08d7e9	340	struct vfsmount *mnt = ERR_PTR(-EINVAL);
40c55319	341	switch (server->nfs_client->rpc_ops->version) {
f7b422b1 DH	342	case 2:
f7b422b1 DH	343	case 3:
54ceac45	344	mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
f7b422b1 DH	345	break;
f7b422b1 DH	346	case 4:
54ceac45	347	mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata);
f7b422b1 DH	348	}
	349	return mnt;
	350	#else
54ceac45	351	return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
f7b422b1 DH	352	#endif
	353	}
	354
	355	/**
	356	* nfs_do_submount - set up mountpoint when crossing a filesystem boundary
f7b422b1 DH	357	* @dentry - parent directory
	358	* @fh - filehandle for new root dentry
	359	* @fattr - attributes for new root inode
7ebb9315	360	* @authflavor - security flavor to use when performing the mount
f7b422b1 DH	361	*
f7b422b1 DH	362	*/
f8ad9c4b	363	static struct vfsmount nfs_do_submount(struct dentry dentry,
66f37509	364	struct nfs_fh *fh,
7ebb9315 BS	365	struct nfs_fattr *fattr,
7ebb9315 BS	366	rpc_authflavor_t authflavor)
f7b422b1 DH	367	{
f7b422b1 DH	368	struct nfs_clone_mount mountdata = {
f8ad9c4b	369	.sb = dentry->d_sb,
f7b422b1 DH	370	.dentry = dentry,
	371	.fh = fh,
	372	.fattr = fattr,
7ebb9315	373	.authflavor = authflavor,
f7b422b1 DH	374	};
	375	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
	376	char page = (char ) __get_free_page(GFP_USER);
	377	char *devname;
	378
54ceac45 DH	379	dprintk("--> nfs_do_submount()\n");
54ceac45 DH	380
3110ff80	381	dprintk("%s: submounting on %s/%s\n", __func__,
f7b422b1 DH	382	dentry->d_parent->d_name.name,
	383	dentry->d_name.name);
	384	if (page == NULL)
	385	goto out;
b514f872	386	devname = nfs_devname(dentry, page, PAGE_SIZE);
f7b422b1 DH	387	mnt = (struct vfsmount *)devname;
	388	if (IS_ERR(devname))
	389	goto free_page;
f8ad9c4b	390	mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
f7b422b1 DH	391	free_page:
	392	free_page((unsigned long)page);
	393	out:
3110ff80	394	dprintk("%s: done\n", __func__);
54ceac45 DH	395
54ceac45 DH	396	dprintk("<-- nfs_do_submount() = %p\n", mnt);
f7b422b1 DH	397	return mnt;
f7b422b1 DH	398	}