path: root/fs/9p/vfs_inode.c

/*
 *  linux/fs/9p/vfs_inode.c
 *
 * This file contains vfs inode ops for the 9P2000 protocol.
 *
 *  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 version 2
 *  as published by the Free Software Foundation.
 *
 *  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
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
#include "cache.h"
#include "xattr.h"
#include "acl.h"

static const struct inode_operations v9fs_dir_inode_operations;
static const struct inode_operations v9fs_dir_inode_operations_dotu;
static const struct inode_operations v9fs_file_inode_operations;
static const struct inode_operations v9fs_symlink_inode_operations;

/**
 * unixmode2p9mode - convert unix mode bits to plan 9
 * @v9ses: v9fs session information
 * @mode: mode to convert
 *
 */

static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
{
	int res;
	res = mode & 0777;
	if (S_ISDIR(mode))
		res |= P9_DMDIR;
	if (v9fs_proto_dotu(v9ses)) {
		if (v9ses->nodev == 0) {
			if (S_ISSOCK(mode))
				res |= P9_DMSOCKET;
			if (S_ISFIFO(mode))
				res |= P9_DMNAMEDPIPE;
			if (S_ISBLK(mode))
				res |= P9_DMDEVICE;
			if (S_ISCHR(mode))
				res |= P9_DMDEVICE;
		}

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

/**
 * p9mode2perm- convert plan9 mode bits to unix permission bits
 * @v9ses: v9fs session information
 * @stat: p9_wstat from which mode need to be derived
 *
 */
static int p9mode2perm(struct v9fs_session_info *v9ses,
		       struct p9_wstat *stat)
{
	int res;
	int mode = stat->mode;

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

		if ((mode & P9_DMSETGID) == P9_DMSETGID)
			res |= S_ISGID;

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

/**
 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 * @v9ses: v9fs session information
 * @stat: p9_wstat from which mode need to be derived
 * @rdev: major number, minor number in case of device files.
 *
 */
static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
			       struct p9_wstat *stat, dev_t *rdev)
{
	int res;
	u32 mode = stat->mode;

	*rdev = 0;
	res = p9mode2perm(v9ses, stat);

	if ((mode & P9_DMDIR) == P9_DMDIR)
		res |= S_IFDIR;
	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
		res |= S_IFLNK;
	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
		 && (v9ses->nodev == 0))
		res |= S_IFSOCK;
	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
		 && (v9ses->nodev == 0))
		res |= S_IFIFO;
	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
		 && (v9ses->nodev == 0)) {
		char type = 0, ext[32];
		int major = -1, minor = -1;

		strlcpy(ext, stat->extension, sizeof(ext));
		sscanf(ext, "%c %i %i", &type, &major, &minor);
		switch (type) {
		case 'c':
			res |= S_IFCHR;
			break;
		case 'b':
			res |= S_IFBLK;
			break;
		default:
			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
				 type, stat->extension);
		};
		*rdev = MKDEV(major, minor);
	} else
		res |= S_IFREG;

	return res;
}

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

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

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

	case O_WRONLY:
		ret = P9_OWRITE;
		break;

	case O_RDWR:
		ret = P9_ORDWR;
		break;
	}

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

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

	return ret;
}

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

void
v9fs_blank_wstat(struct p9_wstat *wstat)
{
	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 = INVALID_UID;
	wstat->n_gid = INVALID_GID;
	wstat->n_muid = INVALID_UID;
	wstat->extension = NULL;
}

/**
 * v9fs_alloc_inode - helper function to allocate an inode
 *
 */
struct inode *v9fs_alloc_inode(struct super_block *sb)
{
	struct v9fs_inode *v9inode;
	v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
							GFP_KERNEL);
	if (!v9inode)
		return NULL;
#ifdef CONFIG_9P_FSCACHE
	v9inode->fscache = NULL;
	spin_lock_init(&v9inode->fscache_lock);
#endif
	v9inode->writeback_fid = NULL;
	v9inode->cache_validity = 0;
	mutex_init(&v9inode->v_mutex);
	return &v9inode->vfs_inode;
}

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

static void v9fs_i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
}

void v9fs_destroy_inode(struct inode *inode)
{
	call_rcu(&inode->i_rcu, v9fs_i_callback);
}

int v9fs_init_inode(struct v9fs_session_info *v9ses,
		    struct inode *inode, umode_t mode, dev_t rdev)
{
	int err = 0;

	inode_init_owner(inode, NULL, mode);
	inode->i_blocks = 0;
	inode->i_rdev = rdev;
	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:
		if (v9fs_proto_dotl(v9ses)) {
			inode->i_op = &v9fs_file_inode_operations_dotl;
		} else if (v9fs_proto_dotu(v9ses)) {
			inode->i_op = &v9fs_file_inode_operations;
		} else {
			p9_debug(P9_DEBUG_ERROR,
				 "special files without extended mode\n");
			err = -EINVAL;
			goto error;
		}
		init_special_inode(inode, inode->i_mode, inode->i_rdev);
		break;
	case S_IFREG:
		if (v9fs_proto_dotl(v9ses)) {
			inode->i_op = &v9fs_file_inode_operations_dotl;