Commit 9cdb3883 authored by Manoj Naik's avatar Manoj Naik Committed by Trond Myklebust
Browse files

NFSv4: Ensure client submounts when following a referral 



Set up mountpoint when hitting a referral on moved error by getting
fs_locations.

Signed-off-by: default avatarManoj Naik <manoj@almaden.ibm.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 61f5164c

fs/nfs/inode.c

+267 −3
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ 
#include <linux/mount.h>

#include <linux/nfs_idmap.h>

#include <linux/vfs.h>

#include <linux/inet.h>

#include <linux/nfs_xdr.h>



#include <asm/system.h>

#include <asm/uaccess.h>
@@ -1714,6 +1716,10 @@ struct nfs_clone_mount { 
	const struct dentry *dentry;

	struct nfs_fh *fh;

	struct nfs_fattr *fattr;

	char *hostname;

	char *mnt_path;

	struct sockaddr_in *addr;

	rpc_authflavor_t authflavor;

};



static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data,
@@ -1724,17 +1730,19 @@ static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data, 
	struct nfs_server *parent = NFS_SB(data->sb);

	struct super_block *sb = ERR_PTR(-EINVAL);

	void *err = ERR_PTR(-ENOMEM);

	char *hostname;

	int len;



	server = kmalloc(sizeof(struct nfs_server), GFP_KERNEL);

	if (server == NULL)

		goto out_err;

	memcpy(server, parent, sizeof(*server));

	len = strlen(parent->hostname) + 1;

	hostname = (data->hostname != NULL) ? data->hostname : parent->hostname;

	len = strlen(hostname) + 1;

	server->hostname = kmalloc(len, GFP_KERNEL);

	if (server->hostname == NULL)

		goto free_server;

	memcpy(server->hostname, parent->hostname, len);

	memcpy(server->hostname, hostname, len);

	if (rpciod_up() != 0)

		goto free_hostname;
@@ -2458,7 +2466,8 @@ static inline void unregister_nfs4fs(void) 
	nfs_unregister_sysctl();

}

#else

#define nfs4_clone_client(a,b) ERR_PTR(-EINVAL)

#define nfs4_fill_sb(a,b)	ERR_PTR(-EINVAL)

#define nfs4_fill_super(a,b)	ERR_PTR(-EINVAL)

#define nfs4_init_once(nfsi) \

	do { } while (0)

#define register_nfs4fs() (0)
@@ -2521,6 +2530,261 @@ struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, 
	return mnt;

}



/* Check if fs_root is valid */

static inline char *nfs4_pathname_string(struct nfs4_pathname *pathname, char *buffer, ssize_t buflen)

{

	char *end = buffer + buflen;

	int n;



	*--end = '\0';

	buflen--;



	n = pathname->ncomponents;

	while (--n >= 0) {

		struct nfs4_string *component = &pathname->components[n];

		buflen -= component->len + 1;

		if (buflen < 0)

			goto Elong;

		end -= component->len;

		memcpy(end, component->data, component->len);

		*--end = '/';

	}

	return end;

Elong:

	return ERR_PTR(-ENAMETOOLONG);

}



/* Check if the string represents a "valid" IPv4 address */

static inline int valid_ipaddr4(const char *buf)

{

	int rc, count, in[4];



	rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);

	if (rc != 4)

		return -EINVAL;

	for (count = 0; count < 4; count++) {

		if (in[count] > 255)

			return -EINVAL;

	}

	return 0;

}



static struct super_block *nfs4_referral_sb(struct nfs_server *server, struct nfs_clone_mount *data)

{

	struct super_block *sb = ERR_PTR(-ENOMEM);

	int len;



	len = strlen(data->mnt_path) + 1;

	server->mnt_path = kmalloc(len, GFP_KERNEL);

	if (server->mnt_path == NULL)

		goto err;

	memcpy(server->mnt_path, data->mnt_path, len);

	memcpy(&server->addr, data->addr, sizeof(struct sockaddr_in));



	sb = sget(&nfs4_fs_type, nfs4_compare_super, nfs_set_super, server);

	if (IS_ERR(sb) || sb->s_root)

		goto free_path;

	return sb;

free_path:

	kfree(server->mnt_path);

err:

	server->mnt_path = NULL;

	return sb;

}



static struct nfs_server *nfs4_referral_server(struct super_block *sb, struct nfs_clone_mount *data)

{

	struct nfs_server *server = NFS_SB(sb);

	struct rpc_timeout timeparms;

	int proto, timeo, retrans;

	void *err;



	proto = IPPROTO_TCP;

	/* Since we are following a referral and there may be alternatives,

	   set the timeouts and retries to low values */

	timeo = 2;

	retrans = 1;

	nfs_init_timeout_values(&timeparms, proto, timeo, retrans);



	server->client = nfs4_create_client(server, &timeparms, proto, data->authflavor);

	if (IS_ERR((err = server->client)))

		goto out_err;



	sb->s_time_gran = 1;

	sb->s_op = &nfs4_sops;

	err = ERR_PTR(nfs_sb_init(sb, data->authflavor));

	if (!IS_ERR(err))

		return server;

out_err:

	return (struct nfs_server *)err;

}



static struct super_block *nfs_referral_nfs4_sb(struct file_system_type *fs_type,

		int flags, const char *dev_name, void *raw_data)

{

	struct nfs_clone_mount *data = raw_data;

	return nfs_clone_generic_sb(data, nfs4_referral_sb, nfs4_referral_server);

}



static struct file_system_type nfs_referral_nfs4_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "nfs4",

	.get_sb		= nfs_referral_nfs4_sb,

	.kill_sb	= nfs4_kill_super,

	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,

};



/**

 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error

 * @mnt_parent - mountpoint of parent directory

 * @dentry - parent directory

 * @fspath - fs path returned in fs_locations

 * @mntpath - mount path to new server

 * @hostname - hostname of new server

 * @addr - host addr of new server

 *

 */

struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,

	     const struct dentry *dentry, struct nfs4_fs_locations *locations)

{

	struct vfsmount *mnt = ERR_PTR(-ENOENT);

	struct nfs_clone_mount mountdata = {

		.sb = mnt_parent->mnt_sb,

		.dentry = dentry,

		.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,

	};

	char *page, *page2;

	char *path, *fs_path;

	char *devname;

	int loc, s;



	if (locations == NULL || locations->nlocations <= 0)

		goto out;



	dprintk("%s: referral at %s/%s\n", __FUNCTION__,

		dentry->d_parent->d_name.name, dentry->d_name.name);



	/* Ensure fs path is a prefix of current dentry path */

	page = (char *) __get_free_page(GFP_USER);

	if (page == NULL)

		goto out;

	page2 = (char *) __get_free_page(GFP_USER);

	if (page2 == NULL)

		goto out;



	path = nfs4_path(dentry, page, PAGE_SIZE);

	if (IS_ERR(path))

		goto out_free;



	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);

	if (IS_ERR(fs_path))

		goto out_free;



	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {

		dprintk("%s: path %s does not begin with fsroot %s\n", __FUNCTION__, path, fs_path);

		goto out_free;

	}



	devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);

	if (IS_ERR(devname)) {

		mnt = (struct vfsmount *)devname;

		goto out_free;

	}



	loc = 0;

	while (loc < locations->nlocations && IS_ERR(mnt)) {

		struct nfs4_fs_location *location = &locations->locations[loc];

		char *mnt_path;



		if (location == NULL || location->nservers <= 0 ||

		    location->rootpath.ncomponents == 0) {

			loc++;

			continue;

		}



		mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);

		if (IS_ERR(mnt_path)) {

			loc++;

			continue;

		}

		mountdata.mnt_path = mnt_path;



		s = 0;

		while (s < location->nservers) {

			struct sockaddr_in addr = {};



			if (location->servers[s].len <= 0 ||

			    valid_ipaddr4(location->servers[s].data) < 0) {

				s++;

				continue;

			}



			mountdata.hostname = location->servers[s].data;

			addr.sin_addr.s_addr = in_aton(mountdata.hostname);

			addr.sin_family = AF_INET;

			addr.sin_port = htons(NFS_PORT);

			mountdata.addr = &addr;



			mnt = vfs_kern_mount(&nfs_referral_nfs4_fs_type, 0, devname, &mountdata);

			if (!IS_ERR(mnt)) {

				break;

			}

			s++;

		}

		loc++;

	}



out_free:

	free_page((unsigned long)page);

	free_page((unsigned long)page2);

out:

	dprintk("%s: done\n", __FUNCTION__);

	return mnt;

}



/*

 * nfs_do_refmount - handle crossing a referral on server

 * @dentry - dentry of referral

 * @nd - nameidata info

 *

 */

struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)

{

	struct vfsmount *mnt = ERR_PTR(-ENOENT);

	struct dentry *parent;

	struct nfs4_fs_locations *fs_locations = NULL;

	struct page *page;

	int err;



	/* BUG_ON(IS_ROOT(dentry)); */

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



	page = alloc_page(GFP_KERNEL);

	if (page == NULL)

		goto out;



	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);

	if (fs_locations == NULL)

		goto out_free;



	/* Get locations */

	parent = dget_parent(dentry);

	dprintk("%s: getting locations for %s/%s\n", __FUNCTION__, parent->d_name.name, dentry->d_name.name);

	err = nfs4_proc_fs_locations(parent->d_inode, dentry, fs_locations, page);

	dput(parent);

	if (err != 0 || fs_locations->nlocations <= 0 ||

	    fs_locations->fs_path.ncomponents <= 0)

		goto out_free;



	mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);

out_free:

	__free_page(page);

	kfree(fs_locations);

out:

	dprintk("%s: done\n", __FUNCTION__);

	return mnt;

}



extern int nfs_init_nfspagecache(void);

extern void nfs_destroy_nfspagecache(void);

extern int nfs_init_readpagecache(void);

include/linux/nfs_fs.h

+2 −0
Original line number Diff line number Diff line
@@ -317,6 +317,8 @@ extern struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, 
					const struct dentry *dentry,

					struct nfs_fh *fh,

					struct nfs_fattr *fattr);

extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent,

					struct dentry *dentry);



/* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */

extern u32 root_nfs_parse_addr(char *name); /*__init*/