[PATCH] v9fs: VFS superblock operations and glue (9e82cf6a) · Commits · e / devices / android_kernel_fairphone_FP5

fs/9p/v9fs.c

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+448 −0

Original line number	Diff line number	Diff line
		/*
		* linux/fs/9p/v9fs.c
		*
		* This file contains functions assisting in mapping VFS to 9P2000
		*
		* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
		* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to:
		* Free Software Foundation
		* 51 Franklin Street, Fifth Floor
		* Boston, MA 02111-1301 USA
		*
		*/

		#include <linux/config.h>
		#include <linux/module.h>
		#include <linux/errno.h>
		#include <linux/fs.h>
		#include <linux/parser.h>
		#include <linux/idr.h>

		#include "debug.h"
		#include "v9fs.h"
		#include "9p.h"
		#include "v9fs_vfs.h"
		#include "transport.h"
		#include "mux.h"
		#include "conv.h"

		/* TODO: sysfs or debugfs interface */
		int v9fs_debug_level = 0; /* feature-rific global debug level */

		/*
		* Option Parsing (code inspired by NFS code)
		*
		*/

		enum {
		/* Options that take integer arguments */
		Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
		Opt_rfdno, Opt_wfdno,
		/* String options */
		Opt_name, Opt_remotename,
		/* Options that take no arguments */
		Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
		/* Error token */
		Opt_err
		};

		static match_table_t tokens = {
		{Opt_port, "port=%u"},
		{Opt_msize, "msize=%u"},
		{Opt_uid, "uid=%u"},
		{Opt_gid, "gid=%u"},
		{Opt_afid, "afid=%u"},
		{Opt_rfdno, "rfdno=%u"},
		{Opt_wfdno, "wfdno=%u"},
		{Opt_debug, "debug=%u"},
		{Opt_name, "name=%s"},
		{Opt_remotename, "aname=%s"},
		{Opt_unix, "proto=unix"},
		{Opt_tcp, "proto=tcp"},
		{Opt_fd, "proto=fd"},
		{Opt_tcp, "tcp"},
		{Opt_unix, "unix"},
		{Opt_fd, "fd"},
		{Opt_legacy, "noextend"},
		{Opt_nodevmap, "nodevmap"},
		{Opt_err, NULL}
		};

		/*
		* Parse option string.
		*/

		/**
		* v9fs_parse_options - parse mount options into session structure
		* @options: options string passed from mount
		* @v9ses: existing v9fs session information
		*
		*/

		static void v9fs_parse_options(char options, struct v9fs_session_info v9ses)
		{
		char *p;
		substring_t args[MAX_OPT_ARGS];
		int option;
		int ret;

		/* setup defaults */
		v9ses->port = V9FS_PORT;
		v9ses->maxdata = 9000;
		v9ses->proto = PROTO_TCP;
		v9ses->extended = 1;
		v9ses->afid = ~0;
		v9ses->debug = 0;
		v9ses->rfdno = ~0;
		v9ses->wfdno = ~0;

		if (!options)
		return;

		while ((p = strsep(&options, ",")) != NULL) {
		int token;
		if (!*p)
		continue;
		token = match_token(p, tokens, args);
		if (token < Opt_name) {
		if ((ret = match_int(&args[0], &option)) < 0) {
		dprintk(DEBUG_ERROR,
		"integer field, but no integer?\n");
		continue;
		}

		}
		switch (token) {
		case Opt_port:
		v9ses->port = option;
		break;
		case Opt_msize:
		v9ses->maxdata = option;
		break;
		case Opt_uid:
		v9ses->uid = option;
		break;
		case Opt_gid:
		v9ses->gid = option;
		break;
		case Opt_afid:
		v9ses->afid = option;
		break;
		case Opt_rfdno:
		v9ses->rfdno = option;
		break;
		case Opt_wfdno:
		v9ses->wfdno = option;
		break;
		case Opt_debug:
		v9ses->debug = option;
		break;
		case Opt_tcp:
		v9ses->proto = PROTO_TCP;
		break;
		case Opt_unix:
		v9ses->proto = PROTO_UNIX;
		break;
		case Opt_fd:
		v9ses->proto = PROTO_FD;
		break;
		case Opt_name:
		match_strcpy(v9ses->name, &args[0]);
		break;
		case Opt_remotename:
		match_strcpy(v9ses->remotename, &args[0]);
		break;
		case Opt_legacy:
		v9ses->extended = 0;
		break;
		case Opt_nodevmap:
		v9ses->nodev = 1;
		break;
		default:
		continue;
		}
		}
		}

		/**
		* v9fs_inode2v9ses - safely extract v9fs session info from super block
		* @inode: inode to extract information from
		*
		* Paranoid function to extract v9ses information from superblock,
		* if anything is missing it will report an error.
		*
		*/

		struct v9fs_session_info v9fs_inode2v9ses(struct inode inode)
		{
		return (inode->i_sb->s_fs_info);
		}

		/**
		* v9fs_get_idpool - allocate numeric id from pool
		* @p - pool to allocate from
		*
		* XXX - This seems to be an awful generic function, should it be in idr.c with
		* the lock included in struct idr?
		*/

		int v9fs_get_idpool(struct v9fs_idpool *p)
		{
		int i = 0;
		int error;

		retry:
		if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
		return 0;

		if (down_interruptible(&p->lock) == -EINTR) {
		eprintk(KERN_WARNING, "Interrupted while locking\n");
		return -1;
		}

		error = idr_get_new(&p->pool, NULL, &i);
		up(&p->lock);

		if (error == -EAGAIN)
		goto retry;
		else if (error)
		return -1;

		return i;
		}

		/**
		* v9fs_put_idpool - release numeric id from pool
		* @p - pool to allocate from
		*
		* XXX - This seems to be an awful generic function, should it be in idr.c with
		* the lock included in struct idr?
		*/

		void v9fs_put_idpool(int id, struct v9fs_idpool *p)
		{
		if (down_interruptible(&p->lock) == -EINTR) {
		eprintk(KERN_WARNING, "Interrupted while locking\n");
		return;
		}
		idr_remove(&p->pool, id);
		up(&p->lock);
		}

		/**
		* v9fs_session_init - initialize session
		* @v9ses: session information structure
		* @dev_name: device being mounted
		* @data: options
		*
		*/

		int
		v9fs_session_init(struct v9fs_session_info *v9ses,
		const char dev_name, char data)
		{
		struct v9fs_fcall *fcall = NULL;
		struct v9fs_transport *trans_proto;
		int n = 0;
		int newfid = -1;
		int retval = -EINVAL;

		v9ses->name = __getname();
		if (!v9ses->name)
		return -ENOMEM;

		v9ses->remotename = __getname();
		if (!v9ses->remotename) {
		putname(v9ses->name);
		return -ENOMEM;
		}

		strcpy(v9ses->name, V9FS_DEFUSER);
		strcpy(v9ses->remotename, V9FS_DEFANAME);

		v9fs_parse_options(data, v9ses);

		/* set global debug level */
		v9fs_debug_level = v9ses->debug;

		/* id pools that are session-dependent: FIDs and TIDs */
		idr_init(&v9ses->fidpool.pool);
		init_MUTEX(&v9ses->fidpool.lock);
		idr_init(&v9ses->tidpool.pool);
		init_MUTEX(&v9ses->tidpool.lock);


		switch (v9ses->proto) {
		case PROTO_TCP:
		trans_proto = &v9fs_trans_tcp;
		break;
		case PROTO_UNIX:
		trans_proto = &v9fs_trans_unix;
		*v9ses->remotename = 0;
		break;
		case PROTO_FD:
		trans_proto = &v9fs_trans_fd;
		*v9ses->remotename = 0;
		if((v9ses->wfdno == ~0) \|\| (v9ses->rfdno == ~0)) {
		printk(KERN_ERR "v9fs: Insufficient options for proto=fd\n");
		retval = -ENOPROTOOPT;
		goto SessCleanUp;
		}
		break;
		default:
		printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
		retval = -ENOPROTOOPT;
		goto SessCleanUp;
		};

		v9ses->transport = trans_proto;

		if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
		eprintk(KERN_ERR, "problem initializing transport\n");
		goto SessCleanUp;
		}

		v9ses->inprogress = 0;
		v9ses->shutdown = 0;
		v9ses->session_hung = 0;

		if ((retval = v9fs_mux_init(v9ses, dev_name)) < 0) {
		dprintk(DEBUG_ERROR, "problem initializing mux\n");
		goto SessCleanUp;
		}

		if (v9ses->afid == ~0) {
		if (v9ses->extended)
		retval =
		v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
		&fcall);
		else
		retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
		&fcall);

		if (retval < 0) {
		dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
		goto FreeFcall;
		}

		/* Really should check for 9P1 and report error */
		if (!strcmp(fcall->params.rversion.version, "9P2000.u")) {
		dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
		v9ses->extended = 1;
		} else {
		dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
		v9ses->extended = 0;
		}

		n = fcall->params.rversion.msize;
		kfree(fcall);

		if (n < v9ses->maxdata)
		v9ses->maxdata = n;
		}

		newfid = v9fs_get_idpool(&v9ses->fidpool);
		if (newfid < 0) {
		eprintk(KERN_WARNING, "couldn't allocate FID\n");
		retval = -ENOMEM;
		goto SessCleanUp;
		}
		/* it is a little bit ugly, but we have to prevent newfid */
		/* being the same as afid, so if it is, get a new fid */
		if (v9ses->afid != ~0 && newfid == v9ses->afid) {
		newfid = v9fs_get_idpool(&v9ses->fidpool);
		if (newfid < 0) {
		eprintk(KERN_WARNING, "couldn't allocate FID\n");
		retval = -ENOMEM;
		goto SessCleanUp;
		}
		}

		if ((retval =
		v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
		v9ses->afid, NULL))
		< 0) {
		dprintk(DEBUG_ERROR, "cannot attach\n");
		goto SessCleanUp;
		}

		if (v9ses->afid != ~0) {
		if (v9fs_t_clunk(v9ses, v9ses->afid, NULL))
		dprintk(DEBUG_ERROR, "clunk failed\n");
		}

		return newfid;

		FreeFcall:
		kfree(fcall);

		SessCleanUp:
		v9fs_session_close(v9ses);
		return retval;
		}

		/**
		* v9fs_session_close - shutdown a session
		* @v9ses: session information structure
		*
		*/

		void v9fs_session_close(struct v9fs_session_info *v9ses)
		{
		if (v9ses->recvproc) {
		send_sig(SIGKILL, v9ses->recvproc, 1);
		wait_for_completion(&v9ses->proccmpl);
		}

		if (v9ses->transport)
		v9ses->transport->close(v9ses->transport);

		putname(v9ses->name);
		putname(v9ses->remotename);
		}

		extern int v9fs_error_init(void);

		/**
		* v9fs_init - Initialize module
		*
		*/

		static int __init init_v9fs(void)
		{
		v9fs_error_init();

		printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");

		return register_filesystem(&v9fs_fs_type);
		}

		/**
		* v9fs_init - shutdown module
		*
		*/

		static void __exit exit_v9fs(void)
		{
		unregister_filesystem(&v9fs_fs_type);
		}

		module_init(init_v9fs)
		module_exit(exit_v9fs)

		MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
		MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
		MODULE_LICENSE("GPL");

fs/9p/v9fs.h

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+105 −0

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		/*
		* V9FS definitions.
		*
		* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
		* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to:
		* Free Software Foundation
		* 51 Franklin Street, Fifth Floor
		* Boston, MA 02111-1301 USA
		*
		*/

		/*
		* Idpool structure provides lock and id management
		*
		*/

		struct v9fs_idpool {
		struct semaphore lock;
		struct idr pool;
		};

		/*
		* Session structure provides information for an opened session
		*
		*/

		struct v9fs_session_info {
		/* options */
		unsigned int maxdata;
		unsigned char extended; /* set to 1 if we are using UNIX extensions */
		unsigned char nodev; /* set to 1 if no disable device mapping */
		unsigned short port; /* port to connect to */
		unsigned short debug; /* debug level */
		unsigned short proto; /* protocol to use */
		unsigned int afid; /* authentication fid */
		unsigned int rfdno; /* read file descriptor number */
		unsigned int wfdno; /* write file descriptor number */


		char name; / user name to mount as */
		char remotename; / name of remote hierarchy being mounted */
		unsigned int uid; /* default uid/muid for legacy support */
		unsigned int gid; /* default gid for legacy support */

		/* book keeping */
		struct v9fs_idpool fidpool; /* The FID pool for file descriptors */
		struct v9fs_idpool tidpool; /* The TID pool for transactions ids */

		/* transport information */
		struct v9fs_transport *transport;

		int inprogress; /* session in progress => true */
		int shutdown; /* session shutting down. no more attaches. */
		unsigned char session_hung;

		/* mux private data */
		struct v9fs_fcall *curfcall;
		wait_queue_head_t read_wait;
		struct completion fcread;
		struct completion proccmpl;
		struct task_struct *recvproc;

		spinlock_t muxlock;
		struct list_head mux_fcalls;
		};

		/* possible values of ->proto */
		enum {
		PROTO_TCP,
		PROTO_UNIX,
		PROTO_FD,
		};

		int v9fs_session_init(struct v9fs_session_info , const char , char *);
		struct v9fs_session_info v9fs_inode2v9ses(struct inode );
		void v9fs_session_close(struct v9fs_session_info *v9ses);
		int v9fs_get_idpool(struct v9fs_idpool *p);
		void v9fs_put_idpool(int id, struct v9fs_idpool *p);
		int v9fs_get_option(char opts, char name, char *buf, int buflen);
		long long v9fs_get_int_option(char opts, char name, long long dflt);
		int v9fs_parse_tcp_devname(const char devname, char addr, char *remotename);

		#define V9FS_MAGIC 0x01021997

		/* other default globals */
		#define V9FS_PORT 564
		#define V9FS_DEFUSER "nobody"
		#define V9FS_DEFANAME ""

		/* inital pool sizes for fids and tags */
		#define V9FS_START_FIDS 8192
		#define V9FS_START_TIDS 256

fs/9p/v9fs_vfs.h

0 → 100644

+53 −0

Original line number	Diff line number	Diff line
		/*
		* V9FS VFS extensions.
		*
		* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
		* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to:
		* Free Software Foundation
		* 51 Franklin Street, Fifth Floor
		* Boston, MA 02111-1301 USA
		*
		*/

		/* plan9 semantics are that created files are implicitly opened.
		* But linux semantics are that you call create, then open.
		* the plan9 approach is superior as it provides an atomic
		* open.
		* we track the create fid here. When the file is opened, if fidopen is
		* non-zero, we use the fid and can skip some steps.
		* there may be a better way to do this, but I don't know it.
		* one BAD way is to clunk the fid on create, then open it again:
		* you lose the atomicity of file open
		*/

		/* special case:
		* unlink calls remove, which is an implicit clunk. So we have to track
		* that kind of thing so that we don't try to clunk a dead fid.
		*/

		extern struct file_system_type v9fs_fs_type;
		extern struct file_operations v9fs_file_operations;
		extern struct file_operations v9fs_dir_operations;
		extern struct dentry_operations v9fs_dentry_operations;

		struct inode v9fs_get_inode(struct super_block sb, int mode);
		ino_t v9fs_qid2ino(struct v9fs_qid *qid);
		void v9fs_mistat2inode(struct v9fs_stat , struct inode ,
		struct super_block *);
		int v9fs_dir_release(struct inode inode, struct file filp);
		int v9fs_file_open(struct inode inode, struct file file);
		void v9fs_inode2mistat(struct inode inode, struct v9fs_stat mistat);
		void v9fs_dentry_release(struct dentry *);

fs/9p/vfs_super.c

0 → 100644

+271 −0

Original line number	Diff line number	Diff line
		/*
		* linux/fs/9p/vfs_super.c
		*
		* This file contians superblock ops for 9P2000. It is intended that
		* you mount this file system on directories.
		*
		* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
		* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to:
		* Free Software Foundation
		* 51 Franklin Street, Fifth Floor
		* Boston, MA 02111-1301 USA
		*
		*/

		#include <linux/kernel.h>
		#include <linux/config.h>
		#include <linux/module.h>
		#include <linux/errno.h>
		#include <linux/fs.h>
		#include <linux/file.h>
		#include <linux/stat.h>
		#include <linux/string.h>
		#include <linux/smp_lock.h>
		#include <linux/inet.h>
		#include <linux/pagemap.h>
		#include <linux/seq_file.h>
		#include <linux/mount.h>
		#include <linux/idr.h>

		#include "debug.h"
		#include "v9fs.h"
		#include "9p.h"
		#include "v9fs_vfs.h"
		#include "conv.h"
		#include "fid.h"

		static void v9fs_clear_inode(struct inode *);
		static struct super_operations v9fs_super_ops;

		/**
		* v9fs_clear_inode - release an inode
		* @inode: inode to release
		*
		*/

		static void v9fs_clear_inode(struct inode *inode)
		{
		filemap_fdatawrite(inode->i_mapping);
		}

		/**
		* v9fs_set_super - set the superblock
		* @s: super block
		* @data: file system specific data
		*
		*/

		static int v9fs_set_super(struct super_block s, void data)
		{
		s->s_fs_info = data;
		return set_anon_super(s, data);
		}

		/**
		* v9fs_fill_super - populate superblock with info
		* @sb: superblock
		* @v9ses: session information
		*
		*/

		static void
		v9fs_fill_super(struct super_block sb, struct v9fs_session_info v9ses,
		int flags)
		{
		sb->s_maxbytes = MAX_LFS_FILESIZE;
		sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
		sb->s_blocksize = 1 << sb->s_blocksize_bits;
		sb->s_magic = V9FS_MAGIC;
		sb->s_op = &v9fs_super_ops;

		sb->s_flags = flags \| MS_ACTIVE \| MS_SYNCHRONOUS \| MS_DIRSYNC \|
		MS_NODIRATIME \| MS_NOATIME;
		}

		/**
		* v9fs_get_sb - mount a superblock
		* @fs_type: file system type
		* @flags: mount flags
		* @dev_name: device name that was mounted
		* @data: mount options
		*
		*/

		static struct super_block *v9fs_get_sb(struct file_system_type
		*fs_type, int flags,
		const char dev_name, void data)
		{
		struct super_block *sb = NULL;
		struct v9fs_fcall *fcall = NULL;
		struct inode *inode = NULL;
		struct dentry *root = NULL;
		struct v9fs_session_info *v9ses = NULL;
		struct v9fs_fid *root_fid = NULL;
		int mode = S_IRWXUGO \| S_ISVTX;
		uid_t uid = current->fsuid;
		gid_t gid = current->fsgid;
		int stat_result = 0;
		int newfid = 0;
		int retval = 0;

		dprintk(DEBUG_VFS, " \n");

		v9ses = kcalloc(1, sizeof(struct v9fs_session_info), GFP_KERNEL);
		if (!v9ses)
		return ERR_PTR(-ENOMEM);

		if ((newfid = v9fs_session_init(v9ses, dev_name, data)) < 0) {
		dprintk(DEBUG_ERROR, "problem initiating session\n");
		retval = newfid;
		goto free_session;
		}

		sb = sget(fs_type, NULL, v9fs_set_super, v9ses);

		v9fs_fill_super(sb, v9ses, flags);

		inode = v9fs_get_inode(sb, S_IFDIR \| mode);
		if (IS_ERR(inode)) {
		retval = PTR_ERR(inode);
		goto put_back_sb;
		}

		inode->i_uid = uid;
		inode->i_gid = gid;

		root = d_alloc_root(inode);

		if (!root) {
		retval = -ENOMEM;
		goto release_inode;
		}

		sb->s_root = root;

		/* Setup the Root Inode */
		root_fid = v9fs_fid_create(root);
		if (root_fid == NULL) {
		retval = -ENOMEM;
		goto release_dentry;
		}

		root_fid->fidopen = 0;
		root_fid->v9ses = v9ses;

		stat_result = v9fs_t_stat(v9ses, newfid, &fcall);
		if (stat_result < 0) {
		dprintk(DEBUG_ERROR, "stat error\n");
		v9fs_t_clunk(v9ses, newfid, NULL);
		v9fs_put_idpool(newfid, &v9ses->fidpool);
		} else {
		root_fid->fid = newfid;
		root_fid->qid = fcall->params.rstat.stat->qid;
		root->d_inode->i_ino =
		v9fs_qid2ino(&fcall->params.rstat.stat->qid);
		v9fs_mistat2inode(fcall->params.rstat.stat, root->d_inode, sb);
		}

		kfree(fcall);

		if (stat_result < 0) {
		retval = stat_result;
		goto release_dentry;
		}

		return sb;

		release_dentry:
		dput(sb->s_root);

		release_inode:
		iput(inode);

		put_back_sb:
		up_write(&sb->s_umount);
		deactivate_super(sb);
		v9fs_session_close(v9ses);

		free_session:
		kfree(v9ses);

		return ERR_PTR(retval);
		}

		/**
		* v9fs_kill_super - Kill Superblock
		* @s: superblock
		*
		*/

		static void v9fs_kill_super(struct super_block *s)
		{
		struct v9fs_session_info *v9ses = s->s_fs_info;

		dprintk(DEBUG_VFS, " %p\n", s);

		v9fs_dentry_release(s->s_root); /* clunk root */

		kill_anon_super(s);

		v9fs_session_close(v9ses);
		kfree(v9ses);
		dprintk(DEBUG_VFS, "exiting kill_super\n");
		}

		/**
		* v9fs_show_options - Show mount options in /proc/mounts
		* @m: seq_file to write to
		* @mnt: mount descriptor
		*
		*/

		static int v9fs_show_options(struct seq_file m, struct vfsmount mnt)
		{
		struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;

		if (v9ses->debug != 0)
		seq_printf(m, ",debug=%u", v9ses->debug);
		if (v9ses->port != V9FS_PORT)
		seq_printf(m, ",port=%u", v9ses->port);
		if (v9ses->maxdata != 9000)
		seq_printf(m, ",msize=%u", v9ses->maxdata);
		if (v9ses->afid != ~0)
		seq_printf(m, ",afid=%u", v9ses->afid);
		if (v9ses->proto == PROTO_UNIX)
		seq_puts(m, ",proto=unix");
		if (v9ses->extended == 0)
		seq_puts(m, ",noextend");
		if (v9ses->nodev == 1)
		seq_puts(m, ",nodevmap");
		seq_printf(m, ",name=%s", v9ses->name);
		seq_printf(m, ",aname=%s", v9ses->remotename);
		seq_printf(m, ",uid=%u", v9ses->uid);
		seq_printf(m, ",gid=%u", v9ses->gid);
		return 0;
		}

		static struct super_operations v9fs_super_ops = {
		.statfs = simple_statfs,
		.clear_inode = v9fs_clear_inode,
		.show_options = v9fs_show_options,
		};

		struct file_system_type v9fs_fs_type = {
		.name = "9P",
		.get_sb = v9fs_get_sb,
		.kill_sb = v9fs_kill_super,
		.owner = THIS_MODULE,
		};