[net-next-2.6.git] / fs / squashfs / super.c

/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
 * Phillip Lougher <phillip@lougher.demon.co.uk>
 *
 * 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,
 * 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 the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * super.c
 */

/*
 * This file implements code to read the superblock, read and initialise
 * in-memory structures at mount time, and all the VFS glue code to register
 * the filesystem.
 */

#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/magic.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"

static struct file_system_type squashfs_fs_type;
static const struct super_operations squashfs_super_ops;

static const struct squashfs_decompressor *supported_squashfs_filesystem(short
	major, short minor, short id)
{
	const struct squashfs_decompressor *decompressor;

	if (major < SQUASHFS_MAJOR) {
		ERROR("Major/Minor mismatch, older Squashfs %d.%d "
			"filesystems are unsupported\n", major, minor);
		return NULL;
	} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
		ERROR("Major/Minor mismatch, trying to mount newer "
			"%d.%d filesystem\n", major, minor);
		ERROR("Please update your kernel\n");
		return NULL;
	}

	decompressor = squashfs_lookup_decompressor(id);
	if (!decompressor->supported) {
		ERROR("Filesystem uses \"%s\" compression. This is not "
			"supported\n", decompressor->name);
		return NULL;
	}

	return decompressor;
}


static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
{
	struct squashfs_sb_info *msblk;
	struct squashfs_super_block *sblk = NULL;
	char b[BDEVNAME_SIZE];
	struct inode *root;
	long long root_inode;
	unsigned short flags;
	unsigned int fragments;
	u64 lookup_table_start;
	int err;

	TRACE("Entered squashfs_fill_superblock\n");

	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
	if (sb->s_fs_info == NULL) {
		ERROR("Failed to allocate squashfs_sb_info\n");
		return -ENOMEM;
	}
	msblk = sb->s_fs_info;

	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
	if (sblk == NULL) {
		ERROR("Failed to allocate squashfs_super_block\n");
		goto failure;
	}

	msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
	msblk->devblksize_log2 = ffz(~msblk->devblksize);

	mutex_init(&msblk->read_data_mutex);
	mutex_init(&msblk->meta_index_mutex);

	/*
	 * msblk->bytes_used is checked in squashfs_read_table to ensure reads
	 * are not beyond filesystem end.  But as we're using
	 * squashfs_read_table here to read the superblock (including the value
	 * of bytes_used) we need to set it to an initial sensible dummy value
	 */
	msblk->bytes_used = sizeof(*sblk);
	err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));

	if (err < 0) {
		ERROR("unable to read squashfs_super_block\n");
		goto failed_mount;
	}

	err = -EINVAL;

	/* Check it is a SQUASHFS superblock */
	sb->s_magic = le32_to_cpu(sblk->s_magic);
	if (sb->s_magic != SQUASHFS_MAGIC) {
		if (!silent)
			ERROR("Can't find a SQUASHFS superblock on %s\n",
						bdevname(sb->s_bdev, b));
		goto failed_mount;
	}

	/* Check the MAJOR & MINOR versions and lookup compression type */
	msblk->decompressor = supported_squashfs_filesystem(
			le16_to_cpu(sblk->s_major),
			le16_to_cpu(sblk->s_minor),
			le16_to_cpu(sblk->compression));
	if (msblk->decompressor == NULL)
		goto failed_mount;

	/*
	 * Check if there's xattrs in the filesystem.  These are not
	 * supported in this version, so warn that they will be ignored.
	 */
	if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
		ERROR("Xattrs in filesystem, these will be ignored\n");

	/* Check the filesystem does not extend beyond the end of the
	   block device */
	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
	if (msblk->bytes_used < 0 || msblk->bytes_used >
			i_size_read(sb->s_bdev->bd_inode))
		goto failed_mount;

	/* Check block size for sanity */
	msblk->block_size = le32_to_cpu(sblk->block_size);
	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
		goto failed_mount;

	/*
	 * Check the system page size is not larger than the filesystem
	 * block size (by default 128K).  This is currently not supported.
	 */
	if (PAGE_CACHE_SIZE > msblk->block_size) {
		ERROR("Page size > filesystem block size (%d).  This is "
			"currently not supported!\n", msblk->block_size);
		goto failed_mount;
	}

	msblk->block_log = le16_to_cpu(sblk->block_log);
	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
		goto failed_mount;

	/* Check the root inode for sanity */
	root_inode = le64_to_cpu(sblk->root_inode);
	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
		goto failed_mount;

	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
	msblk->inodes = le32_to_cpu(sblk->inodes);
	flags = le16_to_cpu(sblk->flags);

	TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
				? "un" : "");
	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
				? "un" : "");
	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
	TRACE("Block size %d\n", msblk->block_size);
	TRACE("Number of inodes %d\n", msblk->inodes);
	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
	TRACE("sblk->fragment_table_start %llx\n",
		(u64) le64_to_cpu(sblk->fragment_table_start));
	TRACE("sblk->id_table_start %llx\n",
		(u64) le64_to_cpu(sblk->id_table_start));

	sb->s_maxbytes = MAX_LFS_FILESIZE;
	sb->s_flags |= MS_RDONLY;
	sb->s_op = &squashfs_super_ops;

	err = -ENOMEM;

	msblk->stream = squashfs_decompressor_init(msblk);
	if (msblk->stream == NULL)
		goto failed_mount;

	msblk->block_cache = squashfs_cache_init("metadata",
			SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
	if (msblk->block_cache == NULL)
		goto failed_mount;

	/* Allocate read_page block */
	msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
	if (msblk->read_page == NULL) {
		ERROR("Failed to allocate read_page block\n");
		goto failed_mount;
	}

	/* Allocate and read id index table */
	msblk->id_table = squashfs_read_id_index_table(sb,
		le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
	if (IS_ERR(msblk->id_table)) {
		err = PTR_ERR(msblk->id_table);
		msblk->id_table = NULL;
		goto failed_mount;
	}

	fragments = le32_to_cpu(sblk->fragments);
	if (fragments == 0)
		goto allocate_lookup_table;

	msblk->fragment_cache = squashfs_cache_init("fragment",
		SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
	if (msblk->fragment_cache == NULL) {
		err = -ENOMEM;
		goto failed_mount;
	}

	/* Allocate and read fragment index table */
	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
		le64_to_cpu(sblk->fragment_table_start), fragments);
	if (IS_ERR(msblk->fragment_index)) {
		err = PTR_ERR(msblk->fragment_index);
		msblk->fragment_index = NULL;
		goto failed_mount;
	}

allocate_lookup_table:
	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
	if (lookup_table_start == SQUASHFS_INVALID_BLK)
		goto allocate_root;

	/* Allocate and read inode lookup table */
	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
		lookup_table_start, msblk->inodes);
	if (IS_ERR(msblk->inode_lookup_table)) {
		err = PTR_ERR(msblk->inode_lookup_table);
		msblk->inode_lookup_table = NULL;
		goto failed_mount;
	}

	sb->s_export_op = &squashfs_export_ops;

allocate_root:
	root = new_inode(sb);
	if (!root) {
		err = -ENOMEM;
		goto failed_mount;
	}

	err = squashfs_read_inode(root, root_inode);
	if (err) {
		iget_failed(root);
		goto failed_mount;
	}
	insert_inode_hash(root);

	sb->s_root = d_alloc_root(root);
	if (sb->s_root == NULL) {
		ERROR("Root inode create failed\n");
		err = -ENOMEM;
		iput(root);
		goto failed_mount;
	}

	TRACE("Leaving squashfs_fill_super\n");
	kfree(sblk);
	return 0;

failed_mount:
	squashfs_cache_delete(msblk->block_cache);
	squashfs_cache_delete(msblk->fragment_cache);
	squashfs_cache_delete(msblk->read_page);
	squashfs_decompressor_free(msblk, msblk->stream);
	kfree(msblk->inode_lookup_table);
	kfree(msblk->fragment_index);
	kfree(msblk->id_table);
	kfree(sb->s_fs_info);
	sb->s_fs_info = NULL;
	kfree(sblk);
	return err;

failure:
	kfree(sb->s_fs_info);
	sb->s_fs_info = NULL;
	return -ENOMEM;
}


static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);

	TRACE("Entered squashfs_statfs\n");

	buf->f_type = SQUASHFS_MAGIC;
	buf->f_bsize = msblk->block_size;
	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
	buf->f_bfree = buf->f_bavail = 0;
	buf->f_files = msblk->inodes;
	buf->f_ffree = 0;
	buf->f_namelen = SQUASHFS_NAME_LEN;
	buf->f_fsid.val[0] = (u32)id;
	buf->f_fsid.val[1] = (u32)(id >> 32);

	return 0;
}


static int squashfs_remount(struct super_block *sb, int *flags, char *data)
{
	*flags |= MS_RDONLY;
	return 0;
}


static void squashfs_put_super(struct super_block *sb)
{
	lock_kernel();

	if (sb->s_fs_info) {
		struct squashfs_sb_info *sbi = sb->s_fs_info;
		squashfs_cache_delete(sbi->block_cache);
		squashfs_cache_delete(sbi->fragment_cache);
		squashfs_cache_delete(sbi->read_page);
		squashfs_decompressor_free(sbi, sbi->stream);
		kfree(sbi->id_table);
		kfree(sbi->fragment_index);
		kfree(sbi->meta_index);
		kfree(sb->s_fs_info);
		sb->s_fs_info = NULL;
	}

	unlock_kernel();
}


static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
				const char *dev_name, void *data,
				struct vfsmount *mnt)
{
	return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
				mnt);
}


static struct kmem_cache *squashfs_inode_cachep;


static void init_once(void *foo)
{
	struct squashfs_inode_info *ei = foo;

	inode_init_once(&ei->vfs_inode);
}


static int __init init_inodecache(void)
{
	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
		sizeof(struct squashfs_inode_info), 0,
		SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once);

	return squashfs_inode_cachep ? 0 : -ENOMEM;
}


static void destroy_inodecache(void)
{
	kmem_cache_destroy(squashfs_inode_cachep);
}


static int __init init_squashfs_fs(void)
{
	int err = init_inodecache();

	if (err)
		return err;

	err = register_filesystem(&squashfs_fs_type);
	if (err) {
		destroy_inodecache();
		return err;
	}

	printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
		"Phillip Lougher\n");

	return 0;
}


static void __exit exit_squashfs_fs(void)
{
	unregister_filesystem(&squashfs_fs_type);
	destroy_inodecache();
}


static struct inode *squashfs_alloc_inode(struct super_block *sb)
{
	struct squashfs_inode_info *ei =
		kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);

	return ei ? &ei->vfs_inode : NULL;
}


static void squashfs_destroy_inode(struct inode *inode)
{
	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
}


static struct file_system_type squashfs_fs_type = {
	.owner = THIS_MODULE,
	.name = "squashfs",
	.get_sb = squashfs_get_sb,
	.kill_sb = kill_block_super,
	.fs_flags = FS_REQUIRES_DEV
};

static const struct super_operations squashfs_super_ops = {
	.alloc_inode = squashfs_alloc_inode,
	.destroy_inode = squashfs_destroy_inode,
	.statfs = squashfs_statfs,
	.put_super = squashfs_put_super,
	.remount_fs = squashfs_remount
};

module_init(init_squashfs_fs);
module_exit(exit_squashfs_fs);
MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
MODULE_LICENSE("GPL");
Commit	Line	Data
0aa66619 PL	1	/*
	2	* Squashfs - a compressed read only filesystem for Linux
	3	*
	4	* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
	5	* Phillip Lougher <phillip@lougher.demon.co.uk>
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version 2,
	10	* or (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	20	*
	21	* super.c
	22	*/
	23
	24	/*
	25	* This file implements code to read the superblock, read and initialise
	26	* in-memory structures at mount time, and all the VFS glue code to register
	27	* the filesystem.
	28	*/
	29
	30	#include <linux/fs.h>
	31	#include <linux/vfs.h>
	32	#include <linux/slab.h>
405f5571	33	#include <linux/smp_lock.h>
0aa66619 PL	34	#include <linux/mutex.h>
	35	#include <linux/pagemap.h>
	36	#include <linux/init.h>
	37	#include <linux/module.h>
1bcbf313	38	#include <linux/magic.h>
0aa66619 PL	39
	40	#include "squashfs_fs.h"
	41	#include "squashfs_fs_sb.h"
	42	#include "squashfs_fs_i.h"
	43	#include "squashfs.h"
4c0f0bb2	44	#include "decompressor.h"
0aa66619 PL	45
0aa66619 PL	46	static struct file_system_type squashfs_fs_type;
b87221de	47	static const struct super_operations squashfs_super_ops;
0aa66619	48
4c0f0bb2 PL	49	static const struct squashfs_decompressor *supported_squashfs_filesystem(short
4c0f0bb2 PL	50	major, short minor, short id)
0aa66619	51	{
4c0f0bb2 PL	52	const struct squashfs_decompressor *decompressor;
4c0f0bb2 PL	53
0aa66619 PL	54	if (major < SQUASHFS_MAJOR) {
	55	ERROR("Major/Minor mismatch, older Squashfs %d.%d "
	56	"filesystems are unsupported\n", major, minor);
4c0f0bb2	57	return NULL;
0aa66619 PL	58	} else if (major > SQUASHFS_MAJOR \|\| minor > SQUASHFS_MINOR) {
	59	ERROR("Major/Minor mismatch, trying to mount newer "
	60	"%d.%d filesystem\n", major, minor);
	61	ERROR("Please update your kernel\n");
4c0f0bb2	62	return NULL;
0aa66619 PL	63	}
0aa66619 PL	64
4c0f0bb2 PL	65	decompressor = squashfs_lookup_decompressor(id);
	66	if (!decompressor->supported) {
	67	ERROR("Filesystem uses \"%s\" compression. This is not "
	68	"supported\n", decompressor->name);
	69	return NULL;
	70	}
0aa66619	71
4c0f0bb2	72	return decompressor;
0aa66619 PL	73	}
	74
	75
	76	static int squashfs_fill_super(struct super_block sb, void data, int silent)
	77	{
	78	struct squashfs_sb_info *msblk;
	79	struct squashfs_super_block *sblk = NULL;
	80	char b[BDEVNAME_SIZE];
	81	struct inode *root;
	82	long long root_inode;
	83	unsigned short flags;
	84	unsigned int fragments;
	85	u64 lookup_table_start;
	86	int err;
	87
	88	TRACE("Entered squashfs_fill_superblock\n");
	89
	90	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
	91	if (sb->s_fs_info == NULL) {
	92	ERROR("Failed to allocate squashfs_sb_info\n");
	93	return -ENOMEM;
	94	}
	95	msblk = sb->s_fs_info;
	96
0aa66619 PL	97	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
	98	if (sblk == NULL) {
	99	ERROR("Failed to allocate squashfs_super_block\n");
	100	goto failure;
	101	}
	102
	103	msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
	104	msblk->devblksize_log2 = ffz(~msblk->devblksize);
	105
	106	mutex_init(&msblk->read_data_mutex);
	107	mutex_init(&msblk->meta_index_mutex);
	108
	109	/*
	110	* msblk->bytes_used is checked in squashfs_read_table to ensure reads
	111	* are not beyond filesystem end. But as we're using
	112	* squashfs_read_table here to read the superblock (including the value
	113	* of bytes_used) we need to set it to an initial sensible dummy value
	114	*/
	115	msblk->bytes_used = sizeof(*sblk);
	116	err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));
	117
	118	if (err < 0) {
	119	ERROR("unable to read squashfs_super_block\n");
	120	goto failed_mount;
	121	}
	122
4c0f0bb2 PL	123	err = -EINVAL;
4c0f0bb2 PL	124
0aa66619 PL	125	/* Check it is a SQUASHFS superblock */
	126	sb->s_magic = le32_to_cpu(sblk->s_magic);
	127	if (sb->s_magic != SQUASHFS_MAGIC) {
	128	if (!silent)
	129	ERROR("Can't find a SQUASHFS superblock on %s\n",
	130	bdevname(sb->s_bdev, b));
0aa66619 PL	131	goto failed_mount;
	132	}
	133
4c0f0bb2 PL	134	/* Check the MAJOR & MINOR versions and lookup compression type */
	135	msblk->decompressor = supported_squashfs_filesystem(
	136	le16_to_cpu(sblk->s_major),
0aa66619 PL	137	le16_to_cpu(sblk->s_minor),
0aa66619 PL	138	le16_to_cpu(sblk->compression));
4c0f0bb2	139	if (msblk->decompressor == NULL)
0aa66619 PL	140	goto failed_mount;
0aa66619 PL	141
0aa66619 PL	142	/*
	143	* Check if there's xattrs in the filesystem. These are not
	144	* supported in this version, so warn that they will be ignored.
	145	*/
	146	if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
	147	ERROR("Xattrs in filesystem, these will be ignored\n");
	148
	149	/* Check the filesystem does not extend beyond the end of the
	150	block device */
	151	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
	152	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
	153	i_size_read(sb->s_bdev->bd_inode))
	154	goto failed_mount;
	155
	156	/* Check block size for sanity */
	157	msblk->block_size = le32_to_cpu(sblk->block_size);
	158	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
	159	goto failed_mount;
	160
fffb47b8 PL	161	/*
	162	* Check the system page size is not larger than the filesystem
	163	* block size (by default 128K). This is currently not supported.
	164	*/
	165	if (PAGE_CACHE_SIZE > msblk->block_size) {
	166	ERROR("Page size > filesystem block size (%d). This is "
	167	"currently not supported!\n", msblk->block_size);
	168	goto failed_mount;
	169	}
	170
0aa66619 PL	171	msblk->block_log = le16_to_cpu(sblk->block_log);
	172	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
	173	goto failed_mount;
	174
	175	/* Check the root inode for sanity */
	176	root_inode = le64_to_cpu(sblk->root_inode);
	177	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
	178	goto failed_mount;
	179
	180	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
	181	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
	182	msblk->inodes = le32_to_cpu(sblk->inodes);
	183	flags = le16_to_cpu(sblk->flags);
	184
	185	TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
	186	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
	187	? "un" : "");
	188	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
	189	? "un" : "");
	190	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
	191	TRACE("Block size %d\n", msblk->block_size);
	192	TRACE("Number of inodes %d\n", msblk->inodes);
	193	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
	194	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
	195	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
	196	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
	197	TRACE("sblk->fragment_table_start %llx\n",
	198	(u64) le64_to_cpu(sblk->fragment_table_start));
	199	TRACE("sblk->id_table_start %llx\n",
	200	(u64) le64_to_cpu(sblk->id_table_start));
	201
	202	sb->s_maxbytes = MAX_LFS_FILESIZE;
	203	sb->s_flags \|= MS_RDONLY;
	204	sb->s_op = &squashfs_super_ops;
	205
	206	err = -ENOMEM;
	207
4c0f0bb2 PL	208	msblk->stream = squashfs_decompressor_init(msblk);
	209	if (msblk->stream == NULL)
	210	goto failed_mount;
	211
0aa66619 PL	212	msblk->block_cache = squashfs_cache_init("metadata",
	213	SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
	214	if (msblk->block_cache == NULL)
	215	goto failed_mount;
	216
	217	/* Allocate read_page block */
	218	msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
	219	if (msblk->read_page == NULL) {
	220	ERROR("Failed to allocate read_page block\n");
	221	goto failed_mount;
	222	}
	223
	224	/* Allocate and read id index table */
	225	msblk->id_table = squashfs_read_id_index_table(sb,
	226	le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
	227	if (IS_ERR(msblk->id_table)) {
	228	err = PTR_ERR(msblk->id_table);
	229	msblk->id_table = NULL;
	230	goto failed_mount;
	231	}
	232
	233	fragments = le32_to_cpu(sblk->fragments);
	234	if (fragments == 0)
	235	goto allocate_lookup_table;
	236
	237	msblk->fragment_cache = squashfs_cache_init("fragment",
	238	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
	239	if (msblk->fragment_cache == NULL) {
	240	err = -ENOMEM;
	241	goto failed_mount;
	242	}
	243
	244	/* Allocate and read fragment index table */
	245	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
	246	le64_to_cpu(sblk->fragment_table_start), fragments);
	247	if (IS_ERR(msblk->fragment_index)) {
	248	err = PTR_ERR(msblk->fragment_index);
	249	msblk->fragment_index = NULL;
	250	goto failed_mount;
	251	}
	252
	253	allocate_lookup_table:
	254	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
	255	if (lookup_table_start == SQUASHFS_INVALID_BLK)
	256	goto allocate_root;
	257
	258	/* Allocate and read inode lookup table */
	259	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
	260	lookup_table_start, msblk->inodes);
	261	if (IS_ERR(msblk->inode_lookup_table)) {
	262	err = PTR_ERR(msblk->inode_lookup_table);
	263	msblk->inode_lookup_table = NULL;
	264	goto failed_mount;
	265	}
	266
	267	sb->s_export_op = &squashfs_export_ops;
	268
	269	allocate_root:
	270	root = new_inode(sb);
	271	if (!root) {
	272	err = -ENOMEM;
	273	goto failed_mount;
	274	}
	275
276	err = squashfs_read_inode(root, root_inode);
277	if (err) {
278	iget_failed(root);
279	goto failed_mount;
280	}
281	insert_inode_hash(root);
282
283	sb->s_root = d_alloc_root(root);
284	if (sb->s_root == NULL) {
285	ERROR("Root inode create failed\n");
286	err = -ENOMEM;
287	iput(root);
288	goto failed_mount;
289	}
290
291	TRACE("Leaving squashfs_fill_super\n");
292	kfree(sblk);
293	return 0;
294
295	failed_mount:
296	squashfs_cache_delete(msblk->block_cache);
297	squashfs_cache_delete(msblk->fragment_cache);
298	squashfs_cache_delete(msblk->read_page);
4c0f0bb2	299	squashfs_decompressor_free(msblk, msblk->stream);
0aa66619 PL	300	kfree(msblk->inode_lookup_table);
	301	kfree(msblk->fragment_index);
	302	kfree(msblk->id_table);
0aa66619 PL	303	kfree(sb->s_fs_info);
	304	sb->s_fs_info = NULL;
	305	kfree(sblk);
	306	return err;
	307
	308	failure:
0aa66619 PL	309	kfree(sb->s_fs_info);
	310	sb->s_fs_info = NULL;
	311	return -ENOMEM;
	312	}
	313
	314
	315	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
	316	{
	317	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
2fc7f562	318	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
0aa66619 PL	319
	320	TRACE("Entered squashfs_statfs\n");
	321
	322	buf->f_type = SQUASHFS_MAGIC;
	323	buf->f_bsize = msblk->block_size;
	324	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
	325	buf->f_bfree = buf->f_bavail = 0;
	326	buf->f_files = msblk->inodes;
	327	buf->f_ffree = 0;
	328	buf->f_namelen = SQUASHFS_NAME_LEN;
2fc7f562 CL	329	buf->f_fsid.val[0] = (u32)id;
2fc7f562 CL	330	buf->f_fsid.val[1] = (u32)(id >> 32);
0aa66619 PL	331
	332	return 0;
	333	}
	334
	335
	336	static int squashfs_remount(struct super_block sb, int flags, char *data)
	337	{
	338	*flags \|= MS_RDONLY;
	339	return 0;
	340	}
	341
	342
	343	static void squashfs_put_super(struct super_block *sb)
	344	{
6cfd0148 CH	345	lock_kernel();
6cfd0148 CH	346
0aa66619 PL	347	if (sb->s_fs_info) {
	348	struct squashfs_sb_info *sbi = sb->s_fs_info;
	349	squashfs_cache_delete(sbi->block_cache);
	350	squashfs_cache_delete(sbi->fragment_cache);
	351	squashfs_cache_delete(sbi->read_page);
4c0f0bb2	352	squashfs_decompressor_free(sbi, sbi->stream);
0aa66619 PL	353	kfree(sbi->id_table);
	354	kfree(sbi->fragment_index);
	355	kfree(sbi->meta_index);
0aa66619 PL	356	kfree(sb->s_fs_info);
	357	sb->s_fs_info = NULL;
	358	}
6cfd0148 CH	359
6cfd0148 CH	360	unlock_kernel();
0aa66619 PL	361	}
	362
	363
	364	static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
	365	const char dev_name, void data,
	366	struct vfsmount *mnt)
	367	{
	368	return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
	369	mnt);
	370	}
	371
	372
	373	static struct kmem_cache *squashfs_inode_cachep;
	374
	375
	376	static void init_once(void *foo)
	377	{
	378	struct squashfs_inode_info *ei = foo;
	379
	380	inode_init_once(&ei->vfs_inode);
	381	}
	382
	383
	384	static int __init init_inodecache(void)
	385	{
	386	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
	387	sizeof(struct squashfs_inode_info), 0,
	388	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT, init_once);
	389
	390	return squashfs_inode_cachep ? 0 : -ENOMEM;
	391	}
	392
	393
	394	static void destroy_inodecache(void)
	395	{
	396	kmem_cache_destroy(squashfs_inode_cachep);
	397	}
	398
	399
	400	static int __init init_squashfs_fs(void)
	401	{
	402	int err = init_inodecache();
	403
	404	if (err)
	405	return err;
	406
	407	err = register_filesystem(&squashfs_fs_type);
	408	if (err) {
	409	destroy_inodecache();
	410	return err;
	411	}
	412
118e1ef6	413	printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
0aa66619 PL	414	"Phillip Lougher\n");
	415
	416	return 0;
	417	}
	418
	419
	420	static void __exit exit_squashfs_fs(void)
	421	{
	422	unregister_filesystem(&squashfs_fs_type);
	423	destroy_inodecache();
	424	}
	425
	426
	427	static struct inode squashfs_alloc_inode(struct super_block sb)
	428	{
	429	struct squashfs_inode_info *ei =
	430	kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
	431
	432	return ei ? &ei->vfs_inode : NULL;
	433	}
	434
	435
	436	static void squashfs_destroy_inode(struct inode *inode)
	437	{
	438	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
	439	}
	440
	441
	442	static struct file_system_type squashfs_fs_type = {
	443	.owner = THIS_MODULE,
	444	.name = "squashfs",
	445	.get_sb = squashfs_get_sb,
	446	.kill_sb = kill_block_super,
	447	.fs_flags = FS_REQUIRES_DEV
	448	};
	449
b87221de	450	static const struct super_operations squashfs_super_ops = {
0aa66619 PL	451	.alloc_inode = squashfs_alloc_inode,
	452	.destroy_inode = squashfs_destroy_inode,
	453	.statfs = squashfs_statfs,
	454	.put_super = squashfs_put_super,
	455	.remount_fs = squashfs_remount
	456	};
	457
	458	module_init(init_squashfs_fs);
	459	module_exit(exit_squashfs_fs);
	460	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
	461	MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
	462	MODULE_LICENSE("GPL");