vfs_inode.c 27.4 KB
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/*
 *  linux/fs/9p/vfs_inode.c
 *
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 * This file contains vfs inode ops for the 9P2000 protocol.
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 *
 *  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
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 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
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 *
 *  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/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/namei.h>
#include <linux/idr.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl.h>
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#include <net/9p/9p.h>
#include <net/9p/client.h>
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#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
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#include "cache.h"
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#include "xattr.h"
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#include "acl.h"
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static const struct inode_operations v9fs_dir_inode_operations;
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static const struct inode_operations v9fs_dir_inode_operations_dotu;
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static const struct inode_operations v9fs_file_inode_operations;
static const struct inode_operations v9fs_symlink_inode_operations;
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/**
 * unixmode2p9mode - convert unix mode bits to plan 9
 * @v9ses: v9fs session information
 * @mode: mode to convert
 *
 */

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static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
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{
	int res;
	res = mode & 0777;
	if (S_ISDIR(mode))
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		res |= P9_DMDIR;
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	if (v9fs_proto_dotu(v9ses)) {
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		if (S_ISLNK(mode))
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			res |= P9_DMSYMLINK;
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		if (v9ses->nodev == 0) {
			if (S_ISSOCK(mode))
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				res |= P9_DMSOCKET;
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			if (S_ISFIFO(mode))
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				res |= P9_DMNAMEDPIPE;
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			if (S_ISBLK(mode))
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				res |= P9_DMDEVICE;
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			if (S_ISCHR(mode))
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				res |= P9_DMDEVICE;
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		}

		if ((mode & S_ISUID) == S_ISUID)
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			res |= P9_DMSETUID;
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		if ((mode & S_ISGID) == S_ISGID)
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			res |= P9_DMSETGID;
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		if ((mode & S_ISVTX) == S_ISVTX)
			res |= P9_DMSETVTX;
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		if ((mode & P9_DMLINK))
			res |= P9_DMLINK;
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	}

	return res;
}

/**
 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 * @v9ses: v9fs session information
 * @mode: mode to convert
 *
 */

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static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
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{
	int res;

	res = mode & 0777;

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	if ((mode & P9_DMDIR) == P9_DMDIR)
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		res |= S_IFDIR;
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	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
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		res |= S_IFLNK;
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	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
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		 && (v9ses->nodev == 0))
		res |= S_IFSOCK;
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	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
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		 && (v9ses->nodev == 0))
		res |= S_IFIFO;
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	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
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		 && (v9ses->nodev == 0))
		res |= S_IFBLK;
	else
		res |= S_IFREG;

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	if (v9fs_proto_dotu(v9ses)) {
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		if ((mode & P9_DMSETUID) == P9_DMSETUID)
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			res |= S_ISUID;

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		if ((mode & P9_DMSETGID) == P9_DMSETGID)
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			res |= S_ISGID;
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		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
			res |= S_ISVTX;
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	}

	return res;
}

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/**
 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 * @uflags: flags to convert
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 * @extended: if .u extensions are active
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 */

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int v9fs_uflags2omode(int uflags, int extended)
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{
	int ret;

	ret = 0;
	switch (uflags&3) {
	default:
	case O_RDONLY:
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		ret = P9_OREAD;
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		break;

	case O_WRONLY:
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		ret = P9_OWRITE;
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		break;

	case O_RDWR:
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		ret = P9_ORDWR;
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		break;
	}

	if (uflags & O_TRUNC)
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		ret |= P9_OTRUNC;
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	if (extended) {
		if (uflags & O_EXCL)
			ret |= P9_OEXCL;

		if (uflags & O_APPEND)
			ret |= P9_OAPPEND;
	}
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	return ret;
}

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/**
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 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 * @wstat: structure to initialize
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 *
 */

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void
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v9fs_blank_wstat(struct p9_wstat *wstat)
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{
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	wstat->type = ~0;
	wstat->dev = ~0;
	wstat->qid.type = ~0;
	wstat->qid.version = ~0;
	*((long long *)&wstat->qid.path) = ~0;
	wstat->mode = ~0;
	wstat->atime = ~0;
	wstat->mtime = ~0;
	wstat->length = ~0;
	wstat->name = NULL;
	wstat->uid = NULL;
	wstat->gid = NULL;
	wstat->muid = NULL;
	wstat->n_uid = ~0;
	wstat->n_gid = ~0;
	wstat->n_muid = ~0;
	wstat->extension = NULL;
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}

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#ifdef CONFIG_9P_FSCACHE
/**
 * v9fs_alloc_inode - helper function to allocate an inode
 * This callback is executed before setting up the inode so that we
 * can associate a vcookie with each inode.
 *
 */

struct inode *v9fs_alloc_inode(struct super_block *sb)
{
	struct v9fs_cookie *vcookie;
	vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
							 GFP_KERNEL);
	if (!vcookie)
		return NULL;

	vcookie->fscache = NULL;
	vcookie->qid = NULL;
	spin_lock_init(&vcookie->lock);
	return &vcookie->inode;
}

/**
 * v9fs_destroy_inode - destroy an inode
 *
 */

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static void v9fs_i_callback(struct rcu_head *head)
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{
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	struct inode *inode = container_of(head, struct inode, i_rcu);
	INIT_LIST_HEAD(&inode->i_dentry);
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	kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
}
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void v9fs_destroy_inode(struct inode *inode)
{
	call_rcu(&inode->i_rcu, v9fs_i_callback);
}
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#endif

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/**
 * v9fs_get_inode - helper function to setup an inode
 * @sb: superblock
 * @mode: mode to setup inode with
 *
 */

struct inode *v9fs_get_inode(struct super_block *sb, int mode)
{
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	int err;
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	struct inode *inode;
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	struct v9fs_session_info *v9ses = sb->s_fs_info;
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	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
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	inode = new_inode(sb);
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	if (!inode) {
		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
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		return ERR_PTR(-ENOMEM);
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	}

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	inode_init_owner(inode, NULL, mode);
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	inode->i_blocks = 0;
	inode->i_rdev = 0;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	inode->i_mapping->a_ops = &v9fs_addr_operations;

	switch (mode & S_IFMT) {
	case S_IFIFO:
	case S_IFBLK:
	case S_IFCHR:
	case S_IFSOCK:
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		if (v9fs_proto_dotl(v9ses)) {
			inode->i_op = &v9fs_file_inode_operations_dotl;
			inode->i_fop = &v9fs_file_operations_dotl;
		} else if (v9fs_proto_dotu(v9ses)) {
			inode->i_op = &v9fs_file_inode_operations;
			inode->i_fop = &v9fs_file_operations;
		} else {
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			P9_DPRINTK(P9_DEBUG_ERROR,
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				   "special files without extended mode\n");
			err = -EINVAL;
			goto error;
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		}
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		init_special_inode(inode, inode->i_mode, inode->i_rdev);
		break;
	case S_IFREG:
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		if (v9fs_proto_dotl(v9ses)) {
			inode->i_op = &v9fs_file_inode_operations_dotl;
			inode->i_fop = &v9fs_file_operations_dotl;
		} else {
			inode->i_op = &v9fs_file_inode_operations;
			inode->i_fop = &v9fs_file_operations;
		}

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		break;
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	case S_IFLNK:
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		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
			P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
						"legacy protocol.\n");
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			err = -EINVAL;
			goto error;
		}
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		if (v9fs_proto_dotl(v9ses))
			inode->i_op = &v9fs_symlink_inode_operations_dotl;
		else
			inode->i_op = &v9fs_symlink_inode_operations;

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		break;
	case S_IFDIR:
		inc_nlink(inode);
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		if (v9fs_proto_dotl(v9ses))
			inode->i_op = &v9fs_dir_inode_operations_dotl;
		else if (v9fs_proto_dotu(v9ses))
			inode->i_op = &v9fs_dir_inode_operations_dotu;
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		else
			inode->i_op = &v9fs_dir_inode_operations;
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		if (v9fs_proto_dotl(v9ses))
			inode->i_fop = &v9fs_dir_operations_dotl;
		else
			inode->i_fop = &v9fs_dir_operations;

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		break;
	default:
		P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
			   mode, mode & S_IFMT);
		err = -EINVAL;
		goto error;
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	}
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	return inode;
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error:
	iput(inode);
	return ERR_PTR(err);
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}

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/*
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static struct v9fs_fid*
v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
{
	int err;
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	int nfid;
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	struct v9fs_fid *ret;
	struct v9fs_fcall *fcall;

	nfid = v9fs_get_idpool(&v9ses->fidpool);
	if (nfid < 0) {
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		eprintk(KERN_WARNING, "no free fids available\n");
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		return ERR_PTR(-ENOSPC);
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	}

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	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
		&fcall);

	if (err < 0) {
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		if (fcall && fcall->id == RWALK)
			goto clunk_fid;

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		PRINT_FCALL_ERROR("walk error", fcall);
		v9fs_put_idpool(nfid, &v9ses->fidpool);
		goto error;
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	}
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	kfree(fcall);
	fcall = NULL;
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	ret = v9fs_fid_create(v9ses, nfid);
	if (!ret) {
		err = -ENOMEM;
		goto clunk_fid;
	}
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	err = v9fs_fid_insert(ret, dentry);
	if (err < 0) {
		v9fs_fid_destroy(ret);
		goto clunk_fid;
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	}
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	return ret;
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clunk_fid:
	v9fs_t_clunk(v9ses, nfid);
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error:
	kfree(fcall);
	return ERR_PTR(err);
}
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*/
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/**
 * v9fs_clear_inode - release an inode
 * @inode: inode to release
 *
 */
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void v9fs_evict_inode(struct inode *inode)
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{
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	truncate_inode_pages(inode->i_mapping, 0);
	end_writeback(inode);
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	filemap_fdatawrite(inode->i_mapping);

#ifdef CONFIG_9P_FSCACHE
	v9fs_cache_inode_put_cookie(inode);
#endif
}

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struct inode *
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v9fs_inode(struct v9fs_session_info *v9ses, struct p9_fid *fid,
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	struct super_block *sb)
{
	int err, umode;
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	struct inode *ret = NULL;
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	struct p9_wstat *st;
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	st = p9_client_stat(fid);
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	if (IS_ERR(st))
		return ERR_CAST(st);
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	umode = p9mode2unixmode(v9ses, st->mode);
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	ret = v9fs_get_inode(sb, umode);
	if (IS_ERR(ret)) {
		err = PTR_ERR(ret);
		goto error;
	}
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	v9fs_stat2inode(st, ret, sb);
	ret->i_ino = v9fs_qid2ino(&st->qid);
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#ifdef CONFIG_9P_FSCACHE
	v9fs_vcookie_set_qid(ret, &st->qid);
	v9fs_cache_inode_get_cookie(ret);
#endif
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	p9stat_free(st);
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	kfree(st);
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	return ret;
error:
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	p9stat_free(st);
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	kfree(st);
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	return ERR_PTR(err);
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}

/**
 * v9fs_remove - helper function to remove files and directories
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 * @dir: directory inode that is being deleted
 * @file:  dentry that is being deleted
 * @rmdir: removing a directory
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 *
 */

static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
{
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	int retval;
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	struct inode *file_inode;
	struct p9_fid *v9fid;
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	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
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		rmdir);

	file_inode = file->d_inode;
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	v9fid = v9fs_fid_clone(file);
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	if (IS_ERR(v9fid))
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		return PTR_ERR(v9fid);
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	retval = p9_client_remove(v9fid);
	if (!retval)
		drop_nlink(file_inode);
	return retval;
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}

/**
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 * v9fs_create - Create a file
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 * @v9ses: session information
 * @dir: directory that dentry is being created in
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 * @dentry:  dentry that is being created
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 * @extension: 9p2000.u extension string to support devices, etc.
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 * @perm: create permissions
 * @mode: open mode
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 *
 */
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static struct p9_fid *
v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
		struct dentry *dentry, char *extension, u32 perm, u8 mode)
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{
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	int err;
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	char *name;
	struct p9_fid *dfid, *ofid, *fid;
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	struct inode *inode;

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	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);

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	err = 0;
	ofid = NULL;
	fid = NULL;
	name = (char *) dentry->d_name.name;
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	dfid = v9fs_fid_lookup(dentry->d_parent);
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	if (IS_ERR(dfid)) {
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		err = PTR_ERR(dfid);
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		P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
		return ERR_PTR(err);
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	}
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	/* clone a fid to use for creation */
	ofid = p9_client_walk(dfid, 0, NULL, 1);
	if (IS_ERR(ofid)) {
		err = PTR_ERR(ofid);
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		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
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		return ERR_PTR(err);
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	}
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	err = p9_client_fcreate(ofid, name, perm, mode, extension);
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	if (err < 0) {
		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
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		goto error;
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	}
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	/* now walk from the parent so we can get unopened fid */
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	fid = p9_client_walk(dfid, 1, &name, 1);
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	if (IS_ERR(fid)) {
		err = PTR_ERR(fid);
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		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
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		fid = NULL;
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		goto error;
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	}
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	/* instantiate inode and assign the unopened fid to the dentry */
	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
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	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
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		P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
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		goto error;
	}
	d_instantiate(dentry, inode);
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	err = v9fs_fid_add(dentry, fid);
	if (err < 0)
		goto error;

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	return ofid;
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error:
	if (ofid)
		p9_client_clunk(ofid);

	if (fid)
		p9_client_clunk(fid);

	return ERR_PTR(err);
}

/**
 * v9fs_vfs_create - VFS hook to create files
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 * @dir: directory inode that is being created
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 * @dentry:  dentry that is being deleted
 * @mode: create permissions
 * @nd: path information
 *
 */
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static int
v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
		struct nameidata *nd)
{
	int err;
	u32 perm;
	int flags;
	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;
	struct file *filp;

	err = 0;
	fid = NULL;
	v9ses = v9fs_inode2v9ses(dir);
	perm = unixmode2p9mode(v9ses, mode);
	if (nd && nd->flags & LOOKUP_OPEN)
		flags = nd->intent.open.flags - 1;
	else
		flags = O_RDWR;

	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
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				v9fs_uflags2omode(flags,
						v9fs_proto_dotu(v9ses)));
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	if (IS_ERR(fid)) {
		err = PTR_ERR(fid);
		fid = NULL;
		goto error;
	}

	/* if we are opening a file, assign the open fid to the file */
	if (nd && nd->flags & LOOKUP_OPEN) {
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		filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
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		if (IS_ERR(filp)) {
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			err = PTR_ERR(filp);
			goto error;
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		}

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		filp->private_data = fid;
	} else
		p9_client_clunk(fid);
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	return 0;

error:
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	if (fid)
		p9_client_clunk(fid);
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	return err;
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}

/**
 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
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 * @dir:  inode that is being unlinked
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 * @dentry: dentry that is being unlinked
 * @mode: mode for new directory
 *
 */

624
static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
625
{
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	int err;
627
	u32 perm;
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	struct v9fs_session_info *v9ses;
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	struct p9_fid *fid;
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	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
	err = 0;
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	v9ses = v9fs_inode2v9ses(dir);
	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
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	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
	if (IS_ERR(fid)) {
		err = PTR_ERR(fid);
		fid = NULL;
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	}

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	if (fid)
		p9_client_clunk(fid);
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	return err;
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}

/**
 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 * @dir:  inode that is being walked from
 * @dentry: dentry that is being walked to?
 * @nameidata: path data
 *
 */

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struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
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				      struct nameidata *nameidata)
{
	struct super_block *sb;
	struct v9fs_session_info *v9ses;
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	struct p9_fid *dfid, *fid;
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	struct inode *inode;
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	char *name;
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	int result = 0;

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	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
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		dir, dentry->d_name.name, dentry, nameidata);
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	if (dentry->d_name.len > NAME_MAX)
		return ERR_PTR(-ENAMETOOLONG);

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	sb = dir->i_sb;
	v9ses = v9fs_inode2v9ses(dir);
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	/* We can walk d_parent because we hold the dir->i_mutex */
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	dfid = v9fs_fid_lookup(dentry->d_parent);
	if (IS_ERR(dfid))
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		return ERR_CAST(dfid);
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	name = (char *) dentry->d_name.name;
	fid = p9_client_walk(dfid, 1, &name, 1);
	if (IS_ERR(fid)) {
		result = PTR_ERR(fid);
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		if (result == -ENOENT) {
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			inode = NULL;
			goto inst_out;
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		}

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		return ERR_PTR(result);
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	}

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	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
	if (IS_ERR(inode)) {
		result = PTR_ERR(inode);
		inode = NULL;
		goto error;
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	}

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	result = v9fs_fid_add(dentry, fid);
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	if (result < 0)
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		goto error_iput;
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inst_out:
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	d_add(dentry, inode);
	return NULL;

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error_iput:
	iput(inode);
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error:
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	p9_client_clunk(fid);
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	return ERR_PTR(result);
}

/**
 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 * @i:  inode that is being unlinked
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 * @d: dentry that is being unlinked
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 *
 */

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int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
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{
	return v9fs_remove(i, d, 0);
}

/**
 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 * @i:  inode that is being unlinked
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 * @d: dentry that is being unlinked
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 *
 */

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int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
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{
	return v9fs_remove(i, d, 1);
}

/**
 * v9fs_vfs_rename - VFS hook to rename an inode
 * @old_dir:  old dir inode
 * @old_dentry: old dentry
 * @new_dir: new dir inode
 * @new_dentry: new dentry
 *
 */

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int
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v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		struct inode *new_dir, struct dentry *new_dentry)
{
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	struct inode *old_inode;
	struct v9fs_session_info *v9ses;
	struct p9_fid *oldfid;
	struct p9_fid *olddirfid;
	struct p9_fid *newdirfid;
	struct p9_wstat wstat;
	int retval;
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	P9_DPRINTK(P9_DEBUG_VFS, "\n");
	retval = 0;
	old_inode = old_dentry->d_inode;
	v9ses = v9fs_inode2v9ses(old_inode);
	oldfid = v9fs_fid_lookup(old_dentry);
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	if (IS_ERR(oldfid))
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		return PTR_ERR(oldfid);

	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
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	if (IS_ERR(olddirfid)) {
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		retval = PTR_ERR(olddirfid);
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		goto done;
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	}

	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
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	if (IS_ERR(newdirfid)) {
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		retval = PTR_ERR(newdirfid);
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		goto clunk_olddir;
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	}

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	down_write(&v9ses->rename_sem);
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	if (v9fs_proto_dotl(v9ses)) {
		retval = p9_client_rename(oldfid, newdirfid,
					(char *) new_dentry->d_name.name);
		if (retval != -ENOSYS)
			goto clunk_newdir;
	}
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	if (old_dentry->d_parent != new_dentry->d_parent) {
		/*
		 * 9P .u can only handle file rename in the same directory
		 */
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		P9_DPRINTK(P9_DEBUG_ERROR,
				"old dir and new dir are different\n");
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		retval = -EXDEV;
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		goto clunk_newdir;
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	}
795
	v9fs_blank_wstat(&wstat);
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	wstat.muid = v9ses->uname;
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	wstat.name = (char *) new_dentry->d_name.name;
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	retval = p9_client_wstat(oldfid, &wstat);
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clunk_newdir:
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	if (!retval)
		/* successful rename */
		d_move(old_dentry, new_dentry);
	up_write(&v9ses->rename_sem);
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	p9_client_clunk(newdirfid);
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clunk_olddir:
808
	p9_client_clunk(olddirfid);
809

810
done:
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	return retval;
}

/**
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815
 * v9fs_vfs_getattr - retrieve file metadata
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 * @mnt: mount information
 * @dentry: file to get attributes on
 * @stat: metadata structure to populate
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 *
 */

static int
v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
		 struct kstat *stat)
{
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	int err;
	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;
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	struct p9_wstat *st;
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	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
	err = -EPERM;
	v9ses = v9fs_inode2v9ses(dentry->d_inode);
834
	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
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		return simple_getattr(mnt, dentry, stat);

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	fid = v9fs_fid_lookup(dentry);
	if (IS_ERR(fid))
839
		return PTR_ERR(fid);
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	st = p9_client_stat(fid);
	if (IS_ERR(st))
		return PTR_ERR(st);
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845
	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
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		generic_fillattr(dentry->d_inode, stat);

848
	p9stat_free(st);
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	kfree(st);
	return 0;
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}

/**
 * v9fs_vfs_setattr - set file metadata
 * @dentry: file whose metadata to set
 * @iattr: metadata assignment structure
 *
 */

static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
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	int retval;
	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;
	struct p9_wstat wstat;
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	P9_DPRINTK(P9_DEBUG_VFS, "\n");
	retval = -EPERM;
	v9ses = v9fs_inode2v9ses(dentry->d_inode);
	fid = v9fs_fid_lookup(dentry);
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	if(IS_ERR(fid))
		return PTR_ERR(fid);
873

874
	v9fs_blank_wstat(&wstat);
875
	if (iattr->ia_valid & ATTR_MODE)
876
		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
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878

	if (iattr->ia_valid & ATTR_MTIME)
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		wstat.mtime = iattr->ia_mtime.tv_sec;
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881

	if (iattr->ia_valid & ATTR_ATIME)
882
		wstat.atime = iattr->ia_atime.tv_sec;
883
884

	if (iattr->ia_valid & ATTR_SIZE)
885
		wstat.length = iattr->ia_size;
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887
	if (v9fs_proto_dotu(v9ses)) {
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889
		if (iattr->ia_valid & ATTR_UID)
			wstat.n_uid = iattr->ia_uid;
890

891
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		if (iattr->ia_valid & ATTR_GID)
			wstat.n_gid = iattr->ia_gid;
893
894
	}

895
	retval = p9_client_wstat(fid, &wstat);
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896
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	if (retval < 0)
		return retval;
898

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904
	if ((iattr->ia_valid & ATTR_SIZE) &&
	    iattr->ia_size != i_size_read(dentry->d_inode)) {
		retval = vmtruncate(dentry->d_inode, iattr->ia_size);
		if (retval)
			return retval;
	}
905

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	setattr_copy(dentry->d_inode, iattr);
	mark_inode_dirty(dentry->d_inode);
	return 0;
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911
}

/**
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 * v9fs_stat2inode - populate an inode structure with mistat info
 * @stat: Plan 9 metadata (mistat) structure
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 * @inode: inode to populate
 * @sb: superblock of filesystem
 *
 */

void
920
v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
921
	struct super_block *sb)
922
{
923
	char ext[32];
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925
	char tag_name[14];
	unsigned int i_nlink;
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	struct v9fs_session_info *v9ses = sb->s_fs_info;

	inode->i_nlink = 1;

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	inode->i_atime.tv_sec = stat->atime;
	inode->i_mtime.tv_sec = stat->mtime;
	inode->i_ctime.tv_sec = stat->mtime;
933

934
935
	inode->i_uid = v9ses->dfltuid;
	inode->i_gid = v9ses->dfltgid;
936

937
	if (v9fs_proto_dotu(v9ses)) {
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		inode->i_uid = stat->n_uid;
		inode->i_gid = stat->n_gid;
940
	}
941
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	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
		if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
			/*
			 * Hadlink support got added later to
			 * to the .u extension. So there can be
			 * server out there that doesn't support
			 * this even with .u extension. So check
			 * for non NULL stat->extension
			 */
			strncpy(ext, stat->extension, sizeof(ext));
			/* HARDLINKCOUNT %u */
			sscanf(ext, "%13s %u", tag_name, &i_nlink);
			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
				inode->i_nlink = i_nlink;
		}
	}
957
	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
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961
	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
		char type = 0;
		int major = -1;
		int minor = -1;
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963
		strncpy(ext, stat->extension, sizeof(ext));
964
		sscanf(ext, "%c %u %u", &type, &major, &minor);
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		switch (type) {
		case 'c':
			inode->i_mode &= ~S_IFBLK;
			inode->i_mode |= S_IFCHR;
			break;
		case 'b':
			break;
		default:
973
			P9_DPRINTK(P9_DEBUG_ERROR,
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975
				"Unknown special type %c %s\n", type,
				stat->extension);
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977
		};
		inode->i_rdev = MKDEV(major, minor);
978
		init_special_inode(inode, inode->i_mode, inode->i_rdev);
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981
	} else
		inode->i_rdev = 0;

982
	i_size_write(inode, stat->length);
983

984
	/* not real number of blocks, but 512 byte ones ... */
985
	inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
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}

/**
 * v9fs_qid2ino - convert qid into inode number
 * @qid: qid to hash
 *
 * BUG: potential for inode number collisions?
 */

995
ino_t v9fs_qid2ino(struct p9_qid *qid)
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{
	u64 path = qid->path + 2;
	ino_t i = 0;

	if (sizeof(ino_t) == sizeof(path))
		memcpy(&i, &path, sizeof(ino_t));
	else
		i = (ino_t) (path ^ (path >> 32));

	return i;
}

/**
 * v9fs_readlink - read a symlink's location (internal version)
 * @dentry: dentry for symlink
1011
 * @buffer: buffer to load symlink location into
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 * @buflen: length of buffer
 *
 */

static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
{
1018
	int retval;
1019

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1021
	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;
1022
	struct p9_wstat *st;
1023

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	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
	retval = -EPERM;
	v9ses = v9fs_inode2v9ses(dentry->d_inode);
	fid = v9fs_fid_lookup(dentry);
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	if (IS_ERR(fid))
1029
		return PTR_ERR(fid);
1030

1031
	if (!v9fs_proto_dotu(v9ses))
1032
		return -EBADF;
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1036
	st = p9_client_stat(fid);
	if (IS_ERR(st))
		return PTR_ERR(st);
1037

1038
	if (!(st->mode & P9_DMSYMLINK)) {
1039
		retval = -EINVAL;
1040
		goto done;
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1042
1043
	}

	/* copy extension buffer into buffer */
1044
	strncpy(buffer, st->extension, buflen);
1045

1046
	P9_DPRINTK(P9_DEBUG_VFS,
1047
		"%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1048

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1049
	retval = strnlen(buffer, buflen);
1050
done:
1051
	p9stat_free(st);