Commit 55a97593 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Ensure the client submounts, when it crosses a server mountpoint. 



Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 8b4bdcf8

fs/nfs/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -5,7 +5,8 @@ 
obj-$(CONFIG_NFS_FS) += nfs.o



nfs-y 			:= dir.o file.o inode.o nfs2xdr.o pagelist.o \

			   proc.o read.o symlink.o unlink.o write.o

			   proc.o read.o symlink.o unlink.o write.o \

			   namespace.o

nfs-$(CONFIG_ROOT_NFS)	+= nfsroot.o mount_clnt.o      

nfs-$(CONFIG_NFS_V3)	+= nfs3proc.o nfs3xdr.o

nfs-$(CONFIG_NFS_V3_ACL)	+= nfs3acl.o

fs/nfs/dir.c

+16 −0
Original line number Diff line number Diff line
@@ -868,6 +868,17 @@ int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) 
	return (nd->intent.open.flags & O_EXCL) != 0;

}



static inline int nfs_reval_fsid(struct inode *dir,

		struct nfs_fh *fh, struct nfs_fattr *fattr)

{

	struct nfs_server *server = NFS_SERVER(dir);



	if (!nfs_fsid_equal(&server->fsid, &fattr->fsid))

		/* Revalidate fsid on root dir */

		return __nfs_revalidate_inode(server, dir->i_sb->s_root->d_inode);

	return 0;

}



static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)

{

	struct dentry *res;
@@ -900,6 +911,11 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru 
		res = ERR_PTR(error);

		goto out_unlock;

	}

	error = nfs_reval_fsid(dir, &fhandle, &fattr);

	if (error < 0) {

		res = ERR_PTR(error);

		goto out_unlock;

	}

	inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);

	res = (struct dentry *)inode;

	if (IS_ERR(res))

fs/nfs/inode.c

+300 −3
Original line number Diff line number Diff line
@@ -221,6 +221,14 @@ nfs_block_size(unsigned long bsize, unsigned char *nrbitsp) 
	return nfs_block_bits(bsize, nrbitsp);

}



static inline void

nfs_super_set_maxbytes(struct super_block *sb, __u64 maxfilesize)

{

	sb->s_maxbytes = (loff_t)maxfilesize;

	if (sb->s_maxbytes > MAX_LFS_FILESIZE || sb->s_maxbytes <= 0)

		sb->s_maxbytes = MAX_LFS_FILESIZE;

}



/*

 * Obtain the root inode of the file system.

 */
@@ -331,9 +339,7 @@ nfs_sb_init(struct super_block *sb, rpc_authflavor_t authflavor) 
	}

	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;



	sb->s_maxbytes = fsinfo.maxfilesize;

	if (sb->s_maxbytes > MAX_LFS_FILESIZE) 

		sb->s_maxbytes = MAX_LFS_FILESIZE; 

	nfs_super_set_maxbytes(sb, fsinfo.maxfilesize);



	server->client->cl_intr = (server->flags & NFS_MOUNT_INTR) ? 1 : 0;

	server->client->cl_softrtry = (server->flags & NFS_MOUNT_SOFT) ? 1 : 0;
@@ -877,6 +883,11 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr) 
			if (nfs_server_capable(inode, NFS_CAP_READDIRPLUS)

			    && fattr->size <= NFS_LIMIT_READDIRPLUS)

				set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));

			/* Deal with crossing mountpoints */

			if (!nfs_fsid_equal(&NFS_SB(sb)->fsid, &fattr->fsid)) {

				inode->i_op = &nfs_mountpoint_inode_operations;

				inode->i_fop = NULL;

			}

		} else if (S_ISLNK(inode->i_mode))

			inode->i_op = &nfs_symlink_inode_operations;

		else
@@ -1650,6 +1661,141 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
 * File system information

 */



/*

 * nfs_path - reconstruct the path given an arbitrary dentry

 * @base - arbitrary string to prepend to the path

 * @dentry - pointer to dentry

 * @buffer - result buffer

 * @buflen - length of buffer

 *

 * Helper function for constructing the path from the

 * root dentry to an 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.

 */

static char *nfs_path(const char *base, const struct dentry *dentry,

		      char *buffer, ssize_t buflen)

{

	char *end = buffer+buflen;

	int namelen;



	*--end = '\0';

	buflen--;

	spin_lock(&dcache_lock);

	while (!IS_ROOT(dentry)) {

		namelen = dentry->d_name.len;

		buflen -= namelen + 1;

		if (buflen < 0)

			goto Elong;

		end -= namelen;

		memcpy(end, dentry->d_name.name, namelen);

		*--end = '/';

		dentry = dentry->d_parent;

	}

	spin_unlock(&dcache_lock);

	namelen = strlen(base);

	/* Strip off excess slashes in base string */

	while (namelen > 0 && base[namelen - 1] == '/')

		namelen--;

	buflen -= namelen;

	if (buflen < 0)

		goto Elong;

	end -= namelen;

	memcpy(end, base, namelen);

	return end;

Elong:

	return ERR_PTR(-ENAMETOOLONG);

}



struct nfs_clone_mount {

	const struct super_block *sb;

	const struct dentry *dentry;

	struct nfs_fh *fh;

	struct nfs_fattr *fattr;

};



static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data,

		struct super_block *(*clone_client)(struct nfs_server *, struct nfs_clone_mount *))

{

	struct nfs_server *server;

	struct nfs_server *parent = NFS_SB(data->sb);

	struct super_block *sb = ERR_PTR(-EINVAL);

	void *err = ERR_PTR(-ENOMEM);

	struct inode *root_inode;

	struct nfs_fsinfo fsinfo;

	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;

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

	if (server->hostname == NULL)

		goto free_server;

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

	server->fsid = data->fattr->fsid;

	nfs_copy_fh(&server->fh, data->fh);

	if (rpciod_up() != 0)

		goto free_hostname;



	sb = clone_client(server, data);

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

		goto kill_rpciod;



	sb->s_op = data->sb->s_op;

	sb->s_blocksize = data->sb->s_blocksize;

	sb->s_blocksize_bits = data->sb->s_blocksize_bits;

	sb->s_maxbytes = data->sb->s_maxbytes;



	server->client_sys = server->client_acl = ERR_PTR(-EINVAL);

	err = ERR_PTR(-ENOMEM);

	server->io_stats = nfs_alloc_iostats();

	if (server->io_stats == NULL)

		goto out_deactivate;



	server->client = rpc_clone_client(parent->client);

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

		goto out_deactivate;

	if (!IS_ERR(parent->client_sys)) {

		server->client_sys = rpc_clone_client(parent->client_sys);

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

			goto out_deactivate;

	}

	if (!IS_ERR(parent->client_acl)) {

		server->client_acl = rpc_clone_client(parent->client_acl);

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

			goto out_deactivate;

	}

	root_inode = nfs_fhget(sb, data->fh, data->fattr);

	if (!root_inode)

		goto out_deactivate;

	sb->s_root = d_alloc_root(root_inode);

	if (!sb->s_root)

		goto out_put_root;

	fsinfo.fattr = data->fattr;

	if (NFS_PROTO(root_inode)->fsinfo(server, data->fh, &fsinfo) == 0)

		nfs_super_set_maxbytes(sb, fsinfo.maxfilesize);

	sb->s_root->d_op = server->rpc_ops->dentry_ops;

	sb->s_flags |= MS_ACTIVE;

	return sb;

out_put_root:

	iput(root_inode);

out_deactivate:

	up_write(&sb->s_umount);

	deactivate_super(sb);

	return (struct super_block *)err;

kill_rpciod:

	rpciod_down();

free_hostname:

	kfree(server->hostname);

free_server:

	kfree(server);

out_err:

	return (struct super_block *)err;

}



static int nfs_set_super(struct super_block *s, void *data)

{

	s->s_fs_info = data;
@@ -1807,6 +1953,31 @@ static struct file_system_type nfs_fs_type = { 
	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,

};



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

{

	struct super_block *sb;



	sb = sget(&nfs_fs_type, nfs_compare_super, nfs_set_super, server);

	if (!IS_ERR(sb) && sb->s_root == NULL && !(server->flags & NFS_MOUNT_NONLM))

		lockd_up();

	return sb;

}



static struct super_block *nfs_clone_nfs_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, nfs_clone_client);

}



static struct file_system_type clone_nfs_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "nfs",

	.get_sb		= nfs_clone_nfs_sb,

	.kill_sb	= nfs_kill_super,

	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,

};



#ifdef CONFIG_NFS_V4



static void nfs4_clear_inode(struct inode *);
@@ -2156,6 +2327,75 @@ static int param_set_idmap_timeout(const char *val, struct kernel_param *kp) 
module_param_call(idmap_cache_timeout, param_set_idmap_timeout, param_get_int,

		 &nfs_idmap_cache_timeout, 0644);



/* Constructs the SERVER-side path */

static inline char *nfs4_path(const struct dentry *dentry, char *buffer, ssize_t buflen)

{

	return nfs_path(NFS_SB(dentry->d_sb)->mnt_path, dentry, buffer, buflen);

}



static inline char *nfs4_dup_path(const struct dentry *dentry)

{

	char *page = (char *) __get_free_page(GFP_USER);

	char *path;



	path = nfs4_path(dentry, page, PAGE_SIZE);

	if (!IS_ERR(path)) {

		int len = PAGE_SIZE + page - path;

		char *tmp = path;



		path = kmalloc(len, GFP_KERNEL);

		if (path)

			memcpy(path, tmp, len);

		else

			path = ERR_PTR(-ENOMEM);

	}

	free_page((unsigned long)page);

	return path;

}



static struct super_block *nfs4_clone_client(struct nfs_server *server, struct nfs_clone_mount *data)

{

	const struct dentry *dentry = data->dentry;

	struct nfs4_client *clp = server->nfs4_state;

	struct super_block *sb;



	server->mnt_path = nfs4_dup_path(dentry);

	if (IS_ERR(server->mnt_path)) {

		sb = (struct super_block *)server->mnt_path;

		goto err;

	}

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

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

		goto free_path;

	nfs4_server_capabilities(server, &server->fh);



	down_write(&clp->cl_sem);

	atomic_inc(&clp->cl_count);

	list_add_tail(&server->nfs4_siblings, &clp->cl_superblocks);

	up_write(&clp->cl_sem);

	return sb;

free_path:

	kfree(server->mnt_path);

err:

	server->mnt_path = NULL;

	return sb;

}



static struct super_block *nfs_clone_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_clone_client);

}



static struct file_system_type clone_nfs4_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "nfs",

	.get_sb		= nfs_clone_nfs4_sb,

	.kill_sb	= nfs4_kill_super,

	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,

};



#define nfs4_init_once(nfsi) \

	do { \

		INIT_LIST_HEAD(&(nfsi)->open_states); \
@@ -2183,12 +2423,69 @@ static inline void unregister_nfs4fs(void) 
	nfs_unregister_sysctl();

}

#else

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

#define nfs4_init_once(nfsi) \

	do { } while (0)

#define register_nfs4fs() (0)

#define unregister_nfs4fs()

#endif



static inline char *nfs_devname(const struct vfsmount *mnt_parent,

			 const struct dentry *dentry,

			 char *buffer, ssize_t buflen)

{

	return nfs_path(mnt_parent->mnt_devname, dentry, buffer, buflen);

}



/**

 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary

 * @mnt_parent - mountpoint of parent directory

 * @dentry - parent directory

 * @fh - filehandle for new root dentry

 * @fattr - attributes for new root inode

 *

 */

struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,

		const struct dentry *dentry, struct nfs_fh *fh,

		struct nfs_fattr *fattr)

{

	struct nfs_clone_mount mountdata = {

		.sb = mnt_parent->mnt_sb,

		.dentry = dentry,

		.fh = fh,

		.fattr = fattr,

	};

	struct vfsmount *mnt = ERR_PTR(-ENOMEM);

	char *page = (char *) __get_free_page(GFP_USER);

	char *devname;



	dprintk("%s: submounting on %s/%s\n", __FUNCTION__,

			dentry->d_parent->d_name.name,

			dentry->d_name.name);

	if (page == NULL)

		goto out;

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

	mnt = (struct vfsmount *)devname;

	if (IS_ERR(devname))

		goto free_page;

	switch (NFS_SB(mnt_parent->mnt_sb)->rpc_ops->version) {

		case 2:

		case 3:

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

			break;

		case 4:

			mnt = vfs_kern_mount(&clone_nfs4_fs_type, 0, devname, &mountdata);

			break;

		default:

			BUG();

	}

free_page:

	free_page((unsigned long)page);

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);

fs/nfs/namespace.c

0 → 100644
+89 −0
Original line number Diff line number Diff line 
/*

 * linux/fs/nfs/namespace.c

 *

 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>

 *

 * NFS namespace

 */



#include <linux/config.h>



#include <linux/dcache.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>



#define NFSDBG_FACILITY		NFSDBG_VFS



/*

 * nfs_follow_mountpoint - handle crossing a mountpoint on the server

 * @dentry - dentry of mountpoint

 * @nd - nameidata info

 *

 * 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.

 */

static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)

{

	struct vfsmount *mnt;

	struct nfs_server *server = NFS_SERVER(dentry->d_inode);

	struct dentry *parent;

	struct nfs_fh fh;

	struct nfs_fattr fattr;

	int err;



	BUG_ON(IS_ROOT(dentry));

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

	dput(nd->dentry);

	nd->dentry = dget(dentry);

	if (d_mountpoint(nd->dentry))

		goto out_follow;

	/* Look it up again */

	parent = dget_parent(nd->dentry);

	err = server->rpc_ops->lookup(parent->d_inode, &nd->dentry->d_name, &fh, &fattr);

	dput(parent);

	if (err != 0)

		goto out_err;



	mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr);

	err = PTR_ERR(mnt);

	if (IS_ERR(mnt))

		goto out_err;



	mntget(mnt);

	err = do_add_mount(mnt, nd, nd->mnt->mnt_flags, NULL);

	if (err < 0) {

		mntput(mnt);

		if (err == -EBUSY)

			goto out_follow;

		goto out_err;

	}

	mntput(nd->mnt);

	dput(nd->dentry);

	nd->mnt = mnt;

	nd->dentry = dget(mnt->mnt_root);

out:

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

	return ERR_PTR(err);

out_err:

	path_release(nd);

	goto out;

out_follow:

	while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))

		;

	err = 0;

	goto out;

}



struct inode_operations nfs_mountpoint_inode_operations = {

	.follow_link	= nfs_follow_mountpoint,

	.getattr	= nfs_getattr,

};

fs/nfs/nfs4_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -217,6 +217,7 @@ extern int nfs4_proc_renew(struct nfs4_client *, struct rpc_cred *); 
extern int nfs4_do_close(struct inode *inode, struct nfs4_state *state);

extern struct dentry *nfs4_atomic_open(struct inode *, struct dentry *, struct nameidata *);

extern int nfs4_open_revalidate(struct inode *, struct dentry *, int, struct nameidata *);

extern int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle);



extern struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops;

extern struct nfs4_state_recovery_ops nfs4_network_partition_recovery_ops;