[mirror_ubuntu-bionic-kernel.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 <linux/xattr.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, xattr_id_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_id_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_xattr_table;

	/* 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_xattr_table:
	xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
	if (xattr_id_table_start == SQUASHFS_INVALID_BLK)
		goto allocate_root;

	/* Allocate and read xattr id lookup table */
	msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
		xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
	if (IS_ERR(msblk->xattr_id_table)) {
		err = PTR_ERR(msblk->xattr_id_table);
		msblk->xattr_id_table = NULL;
		goto failed_mount;
	}
allocate_root:
	root = new_inode(sb);
	if (!root) {
		err = -ENOMEM;
		goto failed_mount;
	}

	err = squashfs_read_inode(root, root_inode);
	if (err) {
		make_bad_inode(root);
		iput(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(msblk->xattr_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(sbi->inode_lookup_table);
		kfree(sbi->xattr_id_table);
		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>
4b5397dc	39	#include <linux/xattr.h>
0aa66619 PL	40
	41	#include "squashfs_fs.h"
	42	#include "squashfs_fs_sb.h"
	43	#include "squashfs_fs_i.h"
	44	#include "squashfs.h"
4c0f0bb2	45	#include "decompressor.h"
0aa66619 PL	46
0aa66619 PL	47	static struct file_system_type squashfs_fs_type;
b87221de	48	static const struct super_operations squashfs_super_ops;
0aa66619	49
4c0f0bb2 PL	50	static const struct squashfs_decompressor *supported_squashfs_filesystem(short
4c0f0bb2 PL	51	major, short minor, short id)
0aa66619	52	{
4c0f0bb2 PL	53	const struct squashfs_decompressor *decompressor;
4c0f0bb2 PL	54
0aa66619 PL	55	if (major < SQUASHFS_MAJOR) {
	56	ERROR("Major/Minor mismatch, older Squashfs %d.%d "
	57	"filesystems are unsupported\n", major, minor);
4c0f0bb2	58	return NULL;
0aa66619 PL	59	} else if (major > SQUASHFS_MAJOR \|\| minor > SQUASHFS_MINOR) {
	60	ERROR("Major/Minor mismatch, trying to mount newer "
	61	"%d.%d filesystem\n", major, minor);
	62	ERROR("Please update your kernel\n");
4c0f0bb2	63	return NULL;
0aa66619 PL	64	}
0aa66619 PL	65
4c0f0bb2 PL	66	decompressor = squashfs_lookup_decompressor(id);
	67	if (!decompressor->supported) {
	68	ERROR("Filesystem uses \"%s\" compression. This is not "
	69	"supported\n", decompressor->name);
	70	return NULL;
	71	}
0aa66619	72
4c0f0bb2	73	return decompressor;
0aa66619 PL	74	}
	75
	76
	77	static int squashfs_fill_super(struct super_block sb, void data, int silent)
	78	{
	79	struct squashfs_sb_info *msblk;
	80	struct squashfs_super_block *sblk = NULL;
	81	char b[BDEVNAME_SIZE];
	82	struct inode *root;
	83	long long root_inode;
	84	unsigned short flags;
	85	unsigned int fragments;
4b5397dc	86	u64 lookup_table_start, xattr_id_table_start;
0aa66619 PL	87	int err;
	88
	89	TRACE("Entered squashfs_fill_superblock\n");
	90
	91	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
	92	if (sb->s_fs_info == NULL) {
	93	ERROR("Failed to allocate squashfs_sb_info\n");
	94	return -ENOMEM;
	95	}
	96	msblk = sb->s_fs_info;
	97
0aa66619 PL	98	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
	99	if (sblk == NULL) {
	100	ERROR("Failed to allocate squashfs_super_block\n");
	101	goto failure;
	102	}
	103
	104	msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
	105	msblk->devblksize_log2 = ffz(~msblk->devblksize);
	106
	107	mutex_init(&msblk->read_data_mutex);
	108	mutex_init(&msblk->meta_index_mutex);
	109
	110	/*
	111	* msblk->bytes_used is checked in squashfs_read_table to ensure reads
	112	* are not beyond filesystem end. But as we're using
	113	* squashfs_read_table here to read the superblock (including the value
	114	* of bytes_used) we need to set it to an initial sensible dummy value
	115	*/
	116	msblk->bytes_used = sizeof(*sblk);
	117	err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));
	118
	119	if (err < 0) {
	120	ERROR("unable to read squashfs_super_block\n");
	121	goto failed_mount;
	122	}
	123
4c0f0bb2 PL	124	err = -EINVAL;
4c0f0bb2 PL	125
0aa66619 PL	126	/* Check it is a SQUASHFS superblock */
	127	sb->s_magic = le32_to_cpu(sblk->s_magic);
	128	if (sb->s_magic != SQUASHFS_MAGIC) {
	129	if (!silent)
	130	ERROR("Can't find a SQUASHFS superblock on %s\n",
	131	bdevname(sb->s_bdev, b));
0aa66619 PL	132	goto failed_mount;
	133	}
	134
4c0f0bb2 PL	135	/* Check the MAJOR & MINOR versions and lookup compression type */
	136	msblk->decompressor = supported_squashfs_filesystem(
	137	le16_to_cpu(sblk->s_major),
0aa66619 PL	138	le16_to_cpu(sblk->s_minor),
0aa66619 PL	139	le16_to_cpu(sblk->compression));
4c0f0bb2	140	if (msblk->decompressor == NULL)
0aa66619 PL	141	goto failed_mount;
0aa66619 PL	142
0aa66619 PL	143	/*
	144	* Check if there's xattrs in the filesystem. These are not
	145	* supported in this version, so warn that they will be ignored.
	146	*/
4b5397dc	147	if (le64_to_cpu(sblk->xattr_id_table_start) != SQUASHFS_INVALID_BLK)
0aa66619 PL	148	ERROR("Xattrs in filesystem, these will be ignored\n");
	149
	150	/* Check the filesystem does not extend beyond the end of the
	151	block device */
	152	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
	153	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
	154	i_size_read(sb->s_bdev->bd_inode))
	155	goto failed_mount;
	156
	157	/* Check block size for sanity */
	158	msblk->block_size = le32_to_cpu(sblk->block_size);
	159	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
	160	goto failed_mount;
	161
fffb47b8 PL	162	/*
	163	* Check the system page size is not larger than the filesystem
	164	* block size (by default 128K). This is currently not supported.
	165	*/
	166	if (PAGE_CACHE_SIZE > msblk->block_size) {
	167	ERROR("Page size > filesystem block size (%d). This is "
	168	"currently not supported!\n", msblk->block_size);
	169	goto failed_mount;
	170	}
	171
0aa66619 PL	172	msblk->block_log = le16_to_cpu(sblk->block_log);
	173	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
	174	goto failed_mount;
	175
	176	/* Check the root inode for sanity */
	177	root_inode = le64_to_cpu(sblk->root_inode);
	178	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
	179	goto failed_mount;
	180
	181	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
	182	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
	183	msblk->inodes = le32_to_cpu(sblk->inodes);
	184	flags = le16_to_cpu(sblk->flags);
	185
	186	TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
	187	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
	188	? "un" : "");
	189	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
	190	? "un" : "");
	191	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
	192	TRACE("Block size %d\n", msblk->block_size);
	193	TRACE("Number of inodes %d\n", msblk->inodes);
	194	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
	195	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
	196	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
	197	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
	198	TRACE("sblk->fragment_table_start %llx\n",
	199	(u64) le64_to_cpu(sblk->fragment_table_start));
	200	TRACE("sblk->id_table_start %llx\n",
	201	(u64) le64_to_cpu(sblk->id_table_start));
	202
	203	sb->s_maxbytes = MAX_LFS_FILESIZE;
	204	sb->s_flags \|= MS_RDONLY;
	205	sb->s_op = &squashfs_super_ops;
	206
	207	err = -ENOMEM;
	208
4c0f0bb2 PL	209	msblk->stream = squashfs_decompressor_init(msblk);
	210	if (msblk->stream == NULL)
	211	goto failed_mount;
	212
0aa66619 PL	213	msblk->block_cache = squashfs_cache_init("metadata",
	214	SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
	215	if (msblk->block_cache == NULL)
	216	goto failed_mount;
	217
	218	/* Allocate read_page block */
	219	msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
	220	if (msblk->read_page == NULL) {
	221	ERROR("Failed to allocate read_page block\n");
	222	goto failed_mount;
	223	}
	224
	225	/* Allocate and read id index table */
	226	msblk->id_table = squashfs_read_id_index_table(sb,
	227	le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
	228	if (IS_ERR(msblk->id_table)) {
	229	err = PTR_ERR(msblk->id_table);
	230	msblk->id_table = NULL;
	231	goto failed_mount;
	232	}
	233
	234	fragments = le32_to_cpu(sblk->fragments);
	235	if (fragments == 0)
	236	goto allocate_lookup_table;
	237
	238	msblk->fragment_cache = squashfs_cache_init("fragment",
	239	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
	240	if (msblk->fragment_cache == NULL) {
	241	err = -ENOMEM;
	242	goto failed_mount;
	243	}
	244
	245	/* Allocate and read fragment index table */
	246	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
	247	le64_to_cpu(sblk->fragment_table_start), fragments);
	248	if (IS_ERR(msblk->fragment_index)) {
	249	err = PTR_ERR(msblk->fragment_index);
	250	msblk->fragment_index = NULL;
	251	goto failed_mount;
	252	}
	253
	254	allocate_lookup_table:
	255	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
	256	if (lookup_table_start == SQUASHFS_INVALID_BLK)
4b5397dc	257	goto allocate_xattr_table;
0aa66619 PL	258
	259	/* Allocate and read inode lookup table */
	260	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
	261	lookup_table_start, msblk->inodes);
	262	if (IS_ERR(msblk->inode_lookup_table)) {
	263	err = PTR_ERR(msblk->inode_lookup_table);
	264	msblk->inode_lookup_table = NULL;
	265	goto failed_mount;
	266	}
	267
	268	sb->s_export_op = &squashfs_export_ops;
	269
4b5397dc PL	270	allocate_xattr_table:
	271	xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
	272	if (xattr_id_table_start == SQUASHFS_INVALID_BLK)
	273	goto allocate_root;
	274
	275	/* Allocate and read xattr id lookup table */
	276	msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
	277	xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
	278	if (IS_ERR(msblk->xattr_id_table)) {
	279	err = PTR_ERR(msblk->xattr_id_table);
	280	msblk->xattr_id_table = NULL;
	281	goto failed_mount;
	282	}
0aa66619 PL	283	allocate_root:
	284	root = new_inode(sb);
	285	if (!root) {
	286	err = -ENOMEM;
	287	goto failed_mount;
	288	}
	289
	290	err = squashfs_read_inode(root, root_inode);
	291	if (err) {
1cb08e97 PL	292	make_bad_inode(root);
1cb08e97 PL	293	iput(root);
0aa66619 PL	294	goto failed_mount;
	295	}
	296	insert_inode_hash(root);
	297
	298	sb->s_root = d_alloc_root(root);
	299	if (sb->s_root == NULL) {
	300	ERROR("Root inode create failed\n");
	301	err = -ENOMEM;
	302	iput(root);
	303	goto failed_mount;
	304	}
	305
	306	TRACE("Leaving squashfs_fill_super\n");
	307	kfree(sblk);
	308	return 0;
	309
	310	failed_mount:
	311	squashfs_cache_delete(msblk->block_cache);
	312	squashfs_cache_delete(msblk->fragment_cache);
	313	squashfs_cache_delete(msblk->read_page);
4c0f0bb2	314	squashfs_decompressor_free(msblk, msblk->stream);
0aa66619 PL	315	kfree(msblk->inode_lookup_table);
	316	kfree(msblk->fragment_index);
	317	kfree(msblk->id_table);
4b5397dc	318	kfree(msblk->xattr_id_table);
0aa66619 PL	319	kfree(sb->s_fs_info);
	320	sb->s_fs_info = NULL;
	321	kfree(sblk);
	322	return err;
	323
	324	failure:
0aa66619 PL	325	kfree(sb->s_fs_info);
	326	sb->s_fs_info = NULL;
	327	return -ENOMEM;
	328	}
	329
	330
	331	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
	332	{
	333	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
2fc7f562	334	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
0aa66619 PL	335
	336	TRACE("Entered squashfs_statfs\n");
	337
	338	buf->f_type = SQUASHFS_MAGIC;
	339	buf->f_bsize = msblk->block_size;
	340	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
	341	buf->f_bfree = buf->f_bavail = 0;
	342	buf->f_files = msblk->inodes;
	343	buf->f_ffree = 0;
	344	buf->f_namelen = SQUASHFS_NAME_LEN;
2fc7f562 CL	345	buf->f_fsid.val[0] = (u32)id;
2fc7f562 CL	346	buf->f_fsid.val[1] = (u32)(id >> 32);
0aa66619 PL	347
	348	return 0;
	349	}
	350
	351
	352	static int squashfs_remount(struct super_block sb, int flags, char *data)
	353	{
	354	*flags \|= MS_RDONLY;
	355	return 0;
	356	}
	357
	358
	359	static void squashfs_put_super(struct super_block *sb)
	360	{
6cfd0148 CH	361	lock_kernel();
6cfd0148 CH	362
0aa66619 PL	363	if (sb->s_fs_info) {
	364	struct squashfs_sb_info *sbi = sb->s_fs_info;
	365	squashfs_cache_delete(sbi->block_cache);
	366	squashfs_cache_delete(sbi->fragment_cache);
	367	squashfs_cache_delete(sbi->read_page);
4c0f0bb2	368	squashfs_decompressor_free(sbi, sbi->stream);
0aa66619 PL	369	kfree(sbi->id_table);
	370	kfree(sbi->fragment_index);
	371	kfree(sbi->meta_index);
370ec3d1	372	kfree(sbi->inode_lookup_table);
4b5397dc	373	kfree(sbi->xattr_id_table);
0aa66619 PL	374	kfree(sb->s_fs_info);
	375	sb->s_fs_info = NULL;
	376	}
6cfd0148 CH	377
6cfd0148 CH	378	unlock_kernel();
0aa66619 PL	379	}
	380
	381
	382	static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
	383	const char dev_name, void data,
	384	struct vfsmount *mnt)
	385	{
	386	return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
	387	mnt);
	388	}
	389
	390
	391	static struct kmem_cache *squashfs_inode_cachep;
	392
	393
	394	static void init_once(void *foo)
	395	{
	396	struct squashfs_inode_info *ei = foo;
	397
	398	inode_init_once(&ei->vfs_inode);
	399	}
	400
	401
	402	static int __init init_inodecache(void)
	403	{
	404	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
	405	sizeof(struct squashfs_inode_info), 0,
	406	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT, init_once);
	407
	408	return squashfs_inode_cachep ? 0 : -ENOMEM;
	409	}
	410
	411
	412	static void destroy_inodecache(void)
	413	{
	414	kmem_cache_destroy(squashfs_inode_cachep);
	415	}
	416
	417
	418	static int __init init_squashfs_fs(void)
	419	{
	420	int err = init_inodecache();
	421
	422	if (err)
	423	return err;
	424
	425	err = register_filesystem(&squashfs_fs_type);
	426	if (err) {
	427	destroy_inodecache();
	428	return err;
	429	}
	430
118e1ef6	431	printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
0aa66619 PL	432	"Phillip Lougher\n");
	433
	434	return 0;
	435	}
	436
	437
	438	static void __exit exit_squashfs_fs(void)
	439	{
	440	unregister_filesystem(&squashfs_fs_type);
	441	destroy_inodecache();
	442	}
	443
	444
	445	static struct inode squashfs_alloc_inode(struct super_block sb)
	446	{
	447	struct squashfs_inode_info *ei =
	448	kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
	449
	450	return ei ? &ei->vfs_inode : NULL;
	451	}
	452
	453
	454	static void squashfs_destroy_inode(struct inode *inode)
	455	{
	456	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
	457	}
	458
	459
	460	static struct file_system_type squashfs_fs_type = {
	461	.owner = THIS_MODULE,
	462	.name = "squashfs",
	463	.get_sb = squashfs_get_sb,
	464	.kill_sb = kill_block_super,
	465	.fs_flags = FS_REQUIRES_DEV
	466	};
	467
b87221de	468	static const struct super_operations squashfs_super_ops = {
0aa66619 PL	469	.alloc_inode = squashfs_alloc_inode,
	470	.destroy_inode = squashfs_destroy_inode,
	471	.statfs = squashfs_statfs,
	472	.put_super = squashfs_put_super,
	473	.remount_fs = squashfs_remount
	474	};
	475
	476	module_init(init_squashfs_fs);
	477	module_exit(exit_squashfs_fs);
	478	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
	479	MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
	480	MODULE_LICENSE("GPL");