path: root/fs/exofs/super.c

/*
 * Copyright (C) 2005, 2006
 * Avishay Traeger (avishay@gmail.com)
 * Copyright (C) 2008, 2009
 * Boaz Harrosh <bharrosh@panasas.com>
 *
 * Copyrights for code taken from ext2:
 *     Copyright (C) 1992, 1993, 1994, 1995
 *     Remy Card (card@masi.ibp.fr)
 *     Laboratoire MASI - Institut Blaise Pascal
 *     Universite Pierre et Marie Curie (Paris VI)
 *     from
 *     linux/fs/minix/inode.c
 *     Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This file is part of exofs.
 *
 * exofs 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.  Since it is based on ext2, and the only
 * valid version of GPL for the Linux kernel is version 2, the only valid
 * version of GPL for exofs is version 2.
 *
 * exofs 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 exofs; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/string.h>
#include <linux/parser.h>
#include <linux/vfs.h>
#include <linux/random.h>
#include <linux/module.h>
#include <linux/exportfs.h>
#include <linux/slab.h>

#include "exofs.h"

#define EXOFS_DBGMSG2(M...) do {} while (0)

/******************************************************************************
 * MOUNT OPTIONS
 *****************************************************************************/

/*
 * struct to hold what we get from mount options
 */
struct exofs_mountopt {
	bool is_osdname;
	const char *dev_name;
	uint64_t pid;
	int timeout;
};

/*
 * exofs-specific mount-time options.
 */
enum { Opt_name, Opt_pid, Opt_to, Opt_err };

/*
 * Our mount-time options.  These should ideally be 64-bit unsigned, but the
 * kernel's parsing functions do not currently support that.  32-bit should be
 * sufficient for most applications now.
 */
static match_table_t tokens = {
	{Opt_name, "osdname=%s"},
	{Opt_pid, "pid=%u"},
	{Opt_to, "to=%u"},
	{Opt_err, NULL}
};

/*
 * The main option parsing method.  Also makes sure that all of the mandatory
 * mount options were set.
 */
static int parse_options(char *options, struct exofs_mountopt *opts)
{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;
	bool s_pid = false;

	EXOFS_DBGMSG("parse_options %s\n", options);
	/* defaults */
	memset(opts, 0, sizeof(*opts));
	opts->timeout = BLK_DEFAULT_SG_TIMEOUT;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;
		char str[32];

		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_name:
			opts->dev_name = match_strdup(&args[0]);
			if (unlikely(!opts->dev_name)) {
				EXOFS_ERR("Error allocating dev_name");
				return -ENOMEM;
			}
			opts->is_osdname = true;
			break;
		case Opt_pid:
			if (0 == match_strlcpy(str, &args[0], sizeof(str)))
				return -EINVAL;
			opts->pid = simple_strtoull(str, NULL, 0);
			if (opts->pid < EXOFS_MIN_PID) {
				EXOFS_ERR("Partition ID must be >= %u",
					  EXOFS_MIN_PID);
				return -EINVAL;
			}
			s_pid = 1;
			break;
		case Opt_to:
			if (match_int(&args[0], &option))
				return -EINVAL;
			if (option <= 0) {
				EXOFS_ERR("Timout must be > 0");
				return -EINVAL;
			}
			opts->timeout = option * HZ;
			break;
		}
	}

	if (!s_pid) {
		EXOFS_ERR("Need to specify the following options:\n");
		EXOFS_ERR("    -o pid=pid_no_to_use\n");
		return -EINVAL;
	}

	return 0;
}

/******************************************************************************
 * INODE CACHE
 *****************************************************************************/

/*
 * Our inode cache.  Isn't it pretty?
 */
static struct kmem_cache *exofs_inode_cachep;

/*
 * Allocate an inode in the cache
 */
static struct inode *exofs_alloc_inode(struct super_block *sb)
{
	struct exofs_i_info *oi;

	oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL);
	if (!oi)
		return NULL;

	oi->vfs_inode.i_version = 1;
	return &oi->vfs_inode;
}

static void exofs_i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(exofs_inode_cachep, exofs_i(inode));
}

/*
 * Remove an inode from the cache
 */
static void exofs_destroy_inode(struct inode *inode)
{
	call_rcu(&inode->i_rcu, exofs_i_callback);
}

/*
 * Initialize the inode