[mirror_ubuntu-hirsute-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@squashfs.org.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/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"
#include "xattr.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, next_table;
	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;

	msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_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);
	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));

	if (IS_ERR(sblk)) {
		ERROR("unable to read squashfs_super_block\n");
		err = PTR_ERR(sblk);
		sblk = NULL;
		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 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;
	}

	/* Check block log for sanity */
	msblk->block_log = le16_to_cpu(sblk->block_log);
	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
		goto failed_mount;

	/* Check that block_size and block_log match */
	if (msblk->block_size != (1 << msblk->block_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->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;
	}

	msblk->stream = squashfs_decompressor_init(sb, flags);
	if (IS_ERR(msblk->stream)) {
		err = PTR_ERR(msblk->stream);
		msblk->stream = NULL;
		goto failed_mount;
	}

	/* Handle xattrs */
	sb->s_xattr = squashfs_xattr_handlers;
	xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
	if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
		next_table = msblk->bytes_used;
		goto allocate_id_index_table;
	}

	/* 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)) {
		ERROR("unable to read xattr id index table\n");
		err = PTR_ERR(msblk->xattr_id_table);
		msblk->xattr_id_table = NULL;
		if (err != -ENOTSUPP)
			goto failed_mount;
	}
	next_table = msblk->xattr_table;

allocate_id_index_table:
	/* Allocate and read id index table */
	msblk->id_table = squashfs_read_id_index_table(sb,
		le64_to_cpu(sblk->id_table_start), next_table,
		le16_to_cpu(sblk->no_ids));
	if (IS_ERR(msblk->id_table)) {
		ERROR("unable to read id index table\n");
		err = PTR_ERR(msblk->id_table);
		msblk->id_table = NULL;
		goto failed_mount;
	}
	next_table = le64_to_cpu(msblk->id_table[0]);

	/* Handle inode lookup table */
	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
	if (lookup_table_start == SQUASHFS_INVALID_BLK)
		goto handle_fragments;

	/* Allocate and read inode lookup table */
	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
		lookup_table_start, next_table, msblk->inodes);
	if (IS_ERR(msblk->inode_lookup_table)) {
		ERROR("unable to read inode lookup table\n");
		err = PTR_ERR(msblk->inode_lookup_table);
		msblk->inode_lookup_table = NULL;
		goto failed_mount;
	}
	next_table = le64_to_cpu(msblk->inode_lookup_table[0]);

	sb->s_export_op = &squashfs_export_ops;

handle_fragments:
	fragments = le32_to_cpu(sblk->fragments);
	if (fragments == 0)
		goto check_directory_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), next_table, fragments);
	if (IS_ERR(msblk->fragment_index)) {
		ERROR("unable to read fragment index table\n");
		err = PTR_ERR(msblk->fragment_index);
		msblk->fragment_index = NULL;
		goto failed_mount;
	}
	next_table = le64_to_cpu(msblk->fragment_index[0]);

check_directory_table:
	/* Sanity check directory_table */
	if (msblk->directory_table > next_table) {
		err = -EINVAL;
		goto failed_mount;
	}

	/* Sanity check inode_table */
	if (msblk->inode_table >= msblk->directory_table) {
		err = -EINVAL;
		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_make_root(root);
	if (sb->s_root == NULL) {
		ERROR("Root inode create failed\n");
		err = -ENOMEM;
		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;
}


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)
{
	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;
	}
}


static struct dentry *squashfs_mount(struct file_system_type *fs_type,
				int flags, const char *dev_name, void *data)
{
	return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
}


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)
{
	/*
	 * Make sure all delayed rcu free inodes are flushed before we
	 * destroy cache.
	 */
	rcu_barrier();
	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_i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
}

static void squashfs_destroy_inode(struct inode *inode)
{
	call_rcu(&inode->i_rcu, squashfs_i_callback);
}


static struct file_system_type squashfs_fs_type = {
	.owner = THIS_MODULE,
	.name = "squashfs",
	.mount = squashfs_mount,
	.kill_sb = kill_block_super,
	.fs_flags = FS_REQUIRES_DEV
};
MODULE_ALIAS_FS("squashfs");

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@squashfs.org.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
d7f2ff67	5	* Phillip Lougher <phillip@squashfs.org.uk>
0aa66619 PL	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>
	33	#include <linux/mutex.h>
	34	#include <linux/pagemap.h>
	35	#include <linux/init.h>
	36	#include <linux/module.h>
1bcbf313	37	#include <linux/magic.h>
4b5397dc	38	#include <linux/xattr.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"
01e5b4e4	45	#include "xattr.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;
37986f63	86	u64 lookup_table_start, xattr_id_table_start, next_table;
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
7657cacf	98	msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
0aa66619 PL	99	msblk->devblksize_log2 = ffz(~msblk->devblksize);
	100
	101	mutex_init(&msblk->read_data_mutex);
	102	mutex_init(&msblk->meta_index_mutex);
	103
	104	/*
	105	* msblk->bytes_used is checked in squashfs_read_table to ensure reads
	106	* are not beyond filesystem end. But as we're using
	107	* squashfs_read_table here to read the superblock (including the value
	108	* of bytes_used) we need to set it to an initial sensible dummy value
	109	*/
	110	msblk->bytes_used = sizeof(*sblk);
82de647e	111	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
0aa66619	112
82de647e	113	if (IS_ERR(sblk)) {
0aa66619	114	ERROR("unable to read squashfs_super_block\n");
82de647e PL	115	err = PTR_ERR(sblk);
82de647e PL	116	sblk = NULL;
0aa66619 PL	117	goto failed_mount;
	118	}
	119
4c0f0bb2 PL	120	err = -EINVAL;
4c0f0bb2 PL	121
0aa66619 PL	122	/* Check it is a SQUASHFS superblock */
	123	sb->s_magic = le32_to_cpu(sblk->s_magic);
	124	if (sb->s_magic != SQUASHFS_MAGIC) {
	125	if (!silent)
	126	ERROR("Can't find a SQUASHFS superblock on %s\n",
	127	bdevname(sb->s_bdev, b));
0aa66619 PL	128	goto failed_mount;
	129	}
	130
4c0f0bb2 PL	131	/* Check the MAJOR & MINOR versions and lookup compression type */
	132	msblk->decompressor = supported_squashfs_filesystem(
	133	le16_to_cpu(sblk->s_major),
0aa66619 PL	134	le16_to_cpu(sblk->s_minor),
0aa66619 PL	135	le16_to_cpu(sblk->compression));
4c0f0bb2	136	if (msblk->decompressor == NULL)
0aa66619 PL	137	goto failed_mount;
0aa66619 PL	138
0aa66619 PL	139	/* Check the filesystem does not extend beyond the end of the
	140	block device */
	141	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
	142	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
	143	i_size_read(sb->s_bdev->bd_inode))
	144	goto failed_mount;
	145
	146	/* Check block size for sanity */
	147	msblk->block_size = le32_to_cpu(sblk->block_size);
	148	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
	149	goto failed_mount;
	150
fffb47b8 PL	151	/*
	152	* Check the system page size is not larger than the filesystem
	153	* block size (by default 128K). This is currently not supported.
	154	*/
	155	if (PAGE_CACHE_SIZE > msblk->block_size) {
	156	ERROR("Page size > filesystem block size (%d). This is "
	157	"currently not supported!\n", msblk->block_size);
	158	goto failed_mount;
	159	}
	160
4b0180a4	161	/* Check block log for sanity */
0aa66619 PL	162	msblk->block_log = le16_to_cpu(sblk->block_log);
	163	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
	164	goto failed_mount;
	165
4b0180a4 PL	166	/* Check that block_size and block_log match */
	167	if (msblk->block_size != (1 << msblk->block_log))
	168	goto failed_mount;
	169
0aa66619 PL	170	/* Check the root inode for sanity */
	171	root_inode = le64_to_cpu(sblk->root_inode);
	172	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
	173	goto failed_mount;
	174
	175	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
	176	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
	177	msblk->inodes = le32_to_cpu(sblk->inodes);
	178	flags = le16_to_cpu(sblk->flags);
	179
	180	TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
	181	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
	182	? "un" : "");
	183	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
	184	? "un" : "");
	185	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
	186	TRACE("Block size %d\n", msblk->block_size);
	187	TRACE("Number of inodes %d\n", msblk->inodes);
	188	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
	189	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
	190	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
	191	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
	192	TRACE("sblk->fragment_table_start %llx\n",
	193	(u64) le64_to_cpu(sblk->fragment_table_start));
	194	TRACE("sblk->id_table_start %llx\n",
	195	(u64) le64_to_cpu(sblk->id_table_start));
	196
	197	sb->s_maxbytes = MAX_LFS_FILESIZE;
	198	sb->s_flags \|= MS_RDONLY;
	199	sb->s_op = &squashfs_super_ops;
	200
	201	err = -ENOMEM;
	202
	203	msblk->block_cache = squashfs_cache_init("metadata",
	204	SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
	205	if (msblk->block_cache == NULL)
	206	goto failed_mount;
	207
	208	/* Allocate read_page block */
	209	msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
	210	if (msblk->read_page == NULL) {
	211	ERROR("Failed to allocate read_page block\n");
	212	goto failed_mount;
	213	}
	214
b7fc0ff0 PL	215	msblk->stream = squashfs_decompressor_init(sb, flags);
	216	if (IS_ERR(msblk->stream)) {
	217	err = PTR_ERR(msblk->stream);
	218	msblk->stream = NULL;
	219	goto failed_mount;
	220	}
	221
76e002f7 PL	222	/* Handle xattrs */
	223	sb->s_xattr = squashfs_xattr_handlers;
	224	xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
37986f63 PL	225	if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
37986f63 PL	226	next_table = msblk->bytes_used;
76e002f7	227	goto allocate_id_index_table;
37986f63	228	}
76e002f7 PL	229
	230	/* Allocate and read xattr id lookup table */
	231	msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
	232	xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
	233	if (IS_ERR(msblk->xattr_id_table)) {
	234	ERROR("unable to read xattr id index table\n");
	235	err = PTR_ERR(msblk->xattr_id_table);
	236	msblk->xattr_id_table = NULL;
	237	if (err != -ENOTSUPP)
	238	goto failed_mount;
	239	}
37986f63	240	next_table = msblk->xattr_table;
76e002f7 PL	241
76e002f7 PL	242	allocate_id_index_table:
0aa66619 PL	243	/* Allocate and read id index table */
0aa66619 PL	244	msblk->id_table = squashfs_read_id_index_table(sb,
37986f63 PL	245	le64_to_cpu(sblk->id_table_start), next_table,
37986f63 PL	246	le16_to_cpu(sblk->no_ids));
0aa66619	247	if (IS_ERR(msblk->id_table)) {
82de647e	248	ERROR("unable to read id index table\n");
0aa66619 PL	249	err = PTR_ERR(msblk->id_table);
	250	msblk->id_table = NULL;
	251	goto failed_mount;
	252	}
d5b72ce1	253	next_table = le64_to_cpu(msblk->id_table[0]);
0aa66619	254
76e002f7 PL	255	/* Handle inode lookup table */
	256	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
	257	if (lookup_table_start == SQUASHFS_INVALID_BLK)
	258	goto handle_fragments;
	259
	260	/* Allocate and read inode lookup table */
	261	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
ac51a0a7	262	lookup_table_start, next_table, msblk->inodes);
76e002f7 PL	263	if (IS_ERR(msblk->inode_lookup_table)) {
	264	ERROR("unable to read inode lookup table\n");
	265	err = PTR_ERR(msblk->inode_lookup_table);
	266	msblk->inode_lookup_table = NULL;
	267	goto failed_mount;
	268	}
d5b72ce1	269	next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
76e002f7 PL	270
	271	sb->s_export_op = &squashfs_export_ops;
	272
	273	handle_fragments:
0aa66619 PL	274	fragments = le32_to_cpu(sblk->fragments);
0aa66619 PL	275	if (fragments == 0)
1094a4a6	276	goto check_directory_table;
0aa66619 PL	277
	278	msblk->fragment_cache = squashfs_cache_init("fragment",
	279	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
	280	if (msblk->fragment_cache == NULL) {
	281	err = -ENOMEM;
	282	goto failed_mount;
	283	}
	284
	285	/* Allocate and read fragment index table */
	286	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
1cac63cc	287	le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
0aa66619	288	if (IS_ERR(msblk->fragment_index)) {
82de647e	289	ERROR("unable to read fragment index table\n");
0aa66619 PL	290	err = PTR_ERR(msblk->fragment_index);
	291	msblk->fragment_index = NULL;
	292	goto failed_mount;
	293	}
d5b72ce1	294	next_table = le64_to_cpu(msblk->fragment_index[0]);
0aa66619	295
1094a4a6 PL	296	check_directory_table:
1094a4a6 PL	297	/* Sanity check directory_table */
cc37f75a	298	if (msblk->directory_table > next_table) {
1094a4a6 PL	299	err = -EINVAL;
	300	goto failed_mount;
	301	}
	302
	303	/* Sanity check inode_table */
	304	if (msblk->inode_table >= msblk->directory_table) {
	305	err = -EINVAL;
	306	goto failed_mount;
	307	}
	308
	309	/* allocate root */
0aa66619 PL	310	root = new_inode(sb);
	311	if (!root) {
	312	err = -ENOMEM;
	313	goto failed_mount;
	314	}
	315
	316	err = squashfs_read_inode(root, root_inode);
	317	if (err) {
1cb08e97 PL	318	make_bad_inode(root);
1cb08e97 PL	319	iput(root);
0aa66619 PL	320	goto failed_mount;
	321	}
	322	insert_inode_hash(root);
	323
48fde701	324	sb->s_root = d_make_root(root);
0aa66619 PL	325	if (sb->s_root == NULL) {
	326	ERROR("Root inode create failed\n");
	327	err = -ENOMEM;
0aa66619 PL	328	goto failed_mount;
	329	}
	330
	331	TRACE("Leaving squashfs_fill_super\n");
	332	kfree(sblk);
	333	return 0;
	334
	335	failed_mount:
	336	squashfs_cache_delete(msblk->block_cache);
	337	squashfs_cache_delete(msblk->fragment_cache);
	338	squashfs_cache_delete(msblk->read_page);
4c0f0bb2	339	squashfs_decompressor_free(msblk, msblk->stream);
0aa66619 PL	340	kfree(msblk->inode_lookup_table);
	341	kfree(msblk->fragment_index);
	342	kfree(msblk->id_table);
4b5397dc	343	kfree(msblk->xattr_id_table);
0aa66619 PL	344	kfree(sb->s_fs_info);
	345	sb->s_fs_info = NULL;
	346	kfree(sblk);
	347	return err;
0aa66619 PL	348	}
	349
	350
	351	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
	352	{
	353	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
2fc7f562	354	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
0aa66619 PL	355
	356	TRACE("Entered squashfs_statfs\n");
	357
	358	buf->f_type = SQUASHFS_MAGIC;
	359	buf->f_bsize = msblk->block_size;
	360	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
	361	buf->f_bfree = buf->f_bavail = 0;
	362	buf->f_files = msblk->inodes;
	363	buf->f_ffree = 0;
	364	buf->f_namelen = SQUASHFS_NAME_LEN;
2fc7f562 CL	365	buf->f_fsid.val[0] = (u32)id;
2fc7f562 CL	366	buf->f_fsid.val[1] = (u32)(id >> 32);
0aa66619 PL	367
	368	return 0;
	369	}
	370
	371
	372	static int squashfs_remount(struct super_block sb, int flags, char *data)
	373	{
	374	*flags \|= MS_RDONLY;
	375	return 0;
	376	}
	377
	378
	379	static void squashfs_put_super(struct super_block *sb)
	380	{
	381	if (sb->s_fs_info) {
	382	struct squashfs_sb_info *sbi = sb->s_fs_info;
	383	squashfs_cache_delete(sbi->block_cache);
	384	squashfs_cache_delete(sbi->fragment_cache);
	385	squashfs_cache_delete(sbi->read_page);
4c0f0bb2	386	squashfs_decompressor_free(sbi, sbi->stream);
0aa66619 PL	387	kfree(sbi->id_table);
	388	kfree(sbi->fragment_index);
	389	kfree(sbi->meta_index);
370ec3d1	390	kfree(sbi->inode_lookup_table);
4b5397dc	391	kfree(sbi->xattr_id_table);
0aa66619 PL	392	kfree(sb->s_fs_info);
	393	sb->s_fs_info = NULL;
	394	}
	395	}
	396
	397
003a3194 PL	398	static struct dentry squashfs_mount(struct file_system_type fs_type,
003a3194 PL	399	int flags, const char dev_name, void data)
0aa66619	400	{
152a0836	401	return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
0aa66619 PL	402	}
	403
	404
	405	static struct kmem_cache *squashfs_inode_cachep;
	406
	407
	408	static void init_once(void *foo)
	409	{
	410	struct squashfs_inode_info *ei = foo;
	411
	412	inode_init_once(&ei->vfs_inode);
	413	}
	414
	415
	416	static int __init init_inodecache(void)
	417	{
	418	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
	419	sizeof(struct squashfs_inode_info), 0,
	420	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT, init_once);
	421
	422	return squashfs_inode_cachep ? 0 : -ENOMEM;
	423	}
	424
	425
	426	static void destroy_inodecache(void)
	427	{
8c0a8537 KS	428	/*
	429	* Make sure all delayed rcu free inodes are flushed before we
	430	* destroy cache.
	431	*/
	432	rcu_barrier();
0aa66619 PL	433	kmem_cache_destroy(squashfs_inode_cachep);
	434	}
	435
	436
	437	static int __init init_squashfs_fs(void)
	438	{
	439	int err = init_inodecache();
	440
	441	if (err)
	442	return err;
	443
	444	err = register_filesystem(&squashfs_fs_type);
	445	if (err) {
	446	destroy_inodecache();
	447	return err;
	448	}
	449
118e1ef6	450	printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
0aa66619 PL	451	"Phillip Lougher\n");
	452
	453	return 0;
	454	}
	455
	456
	457	static void __exit exit_squashfs_fs(void)
	458	{
	459	unregister_filesystem(&squashfs_fs_type);
	460	destroy_inodecache();
	461	}
	462
	463
	464	static struct inode squashfs_alloc_inode(struct super_block sb)
	465	{
	466	struct squashfs_inode_info *ei =
	467	kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
	468
	469	return ei ? &ei->vfs_inode : NULL;
	470	}
	471
	472
fa0d7e3d	473	static void squashfs_i_callback(struct rcu_head *head)
0aa66619	474	{
fa0d7e3d	475	struct inode *inode = container_of(head, struct inode, i_rcu);
0aa66619 PL	476	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
	477	}
	478
fa0d7e3d NP	479	static void squashfs_destroy_inode(struct inode *inode)
	480	{
	481	call_rcu(&inode->i_rcu, squashfs_i_callback);
	482	}
	483
0aa66619 PL	484
	485	static struct file_system_type squashfs_fs_type = {
	486	.owner = THIS_MODULE,
	487	.name = "squashfs",
152a0836	488	.mount = squashfs_mount,
0aa66619 PL	489	.kill_sb = kill_block_super,
	490	.fs_flags = FS_REQUIRES_DEV
	491	};
3e64fe5b	492	MODULE_ALIAS_FS("squashfs");
0aa66619	493
b87221de	494	static const struct super_operations squashfs_super_ops = {
0aa66619 PL	495	.alloc_inode = squashfs_alloc_inode,
	496	.destroy_inode = squashfs_destroy_inode,
	497	.statfs = squashfs_statfs,
	498	.put_super = squashfs_put_super,
	499	.remount_fs = squashfs_remount
	500	};
	501
	502	module_init(init_squashfs_fs);
	503	module_exit(exit_squashfs_fs);
	504	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
d7f2ff67	505	MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
0aa66619	506	MODULE_LICENSE("GPL");