[linux.git] / fs / squashfs / super.c

/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
 * Phillip Lougher <[email protected]>
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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->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",
		squashfs_max_decompressors(), msblk->block_size);
	if (msblk->read_page == NULL) {
		ERROR("Failed to allocate read_page block\n");
		goto failed_mount;
	}

	msblk->stream = squashfs_decompressor_setup(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_destroy(msblk);
	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)
{
	sync_filesystem(sb);
	*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_destroy(sbi);
		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;
	}

	pr_info("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 <[email protected]>");
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 <[email protected]>
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
c811f5f4 FF	30	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
c811f5f4 FF	31
0aa66619 PL	32	#include <linux/fs.h>
	33	#include <linux/vfs.h>
	34	#include <linux/slab.h>
	35	#include <linux/mutex.h>
	36	#include <linux/pagemap.h>
	37	#include <linux/init.h>
	38	#include <linux/module.h>
1bcbf313	39	#include <linux/magic.h>
4b5397dc	40	#include <linux/xattr.h>
0aa66619 PL	41
	42	#include "squashfs_fs.h"
	43	#include "squashfs_fs_sb.h"
	44	#include "squashfs_fs_i.h"
	45	#include "squashfs.h"
4c0f0bb2	46	#include "decompressor.h"
01e5b4e4	47	#include "xattr.h"
0aa66619 PL	48
0aa66619 PL	49	static struct file_system_type squashfs_fs_type;
b87221de	50	static const struct super_operations squashfs_super_ops;
0aa66619	51
4c0f0bb2 PL	52	static const struct squashfs_decompressor *supported_squashfs_filesystem(short
4c0f0bb2 PL	53	major, short minor, short id)
0aa66619	54	{
4c0f0bb2 PL	55	const struct squashfs_decompressor *decompressor;
4c0f0bb2 PL	56
0aa66619 PL	57	if (major < SQUASHFS_MAJOR) {
	58	ERROR("Major/Minor mismatch, older Squashfs %d.%d "
	59	"filesystems are unsupported\n", major, minor);
4c0f0bb2	60	return NULL;
0aa66619 PL	61	} else if (major > SQUASHFS_MAJOR \|\| minor > SQUASHFS_MINOR) {
	62	ERROR("Major/Minor mismatch, trying to mount newer "
	63	"%d.%d filesystem\n", major, minor);
	64	ERROR("Please update your kernel\n");
4c0f0bb2	65	return NULL;
0aa66619 PL	66	}
0aa66619 PL	67
4c0f0bb2 PL	68	decompressor = squashfs_lookup_decompressor(id);
	69	if (!decompressor->supported) {
	70	ERROR("Filesystem uses \"%s\" compression. This is not "
	71	"supported\n", decompressor->name);
	72	return NULL;
	73	}
0aa66619	74
4c0f0bb2	75	return decompressor;
0aa66619 PL	76	}
	77
	78
	79	static int squashfs_fill_super(struct super_block sb, void data, int silent)
	80	{
	81	struct squashfs_sb_info *msblk;
	82	struct squashfs_super_block *sblk = NULL;
	83	char b[BDEVNAME_SIZE];
	84	struct inode *root;
	85	long long root_inode;
	86	unsigned short flags;
	87	unsigned int fragments;
37986f63	88	u64 lookup_table_start, xattr_id_table_start, next_table;
0aa66619 PL	89	int err;
	90
	91	TRACE("Entered squashfs_fill_superblock\n");
	92
	93	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
	94	if (sb->s_fs_info == NULL) {
	95	ERROR("Failed to allocate squashfs_sb_info\n");
	96	return -ENOMEM;
	97	}
	98	msblk = sb->s_fs_info;
	99
7657cacf	100	msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
0aa66619 PL	101	msblk->devblksize_log2 = ffz(~msblk->devblksize);
0aa66619 PL	102
0aa66619 PL	103	mutex_init(&msblk->meta_index_mutex);
	104
	105	/*
	106	* msblk->bytes_used is checked in squashfs_read_table to ensure reads
	107	* are not beyond filesystem end. But as we're using
	108	* squashfs_read_table here to read the superblock (including the value
	109	* of bytes_used) we need to set it to an initial sensible dummy value
	110	*/
	111	msblk->bytes_used = sizeof(*sblk);
82de647e	112	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
0aa66619	113
82de647e	114	if (IS_ERR(sblk)) {
0aa66619	115	ERROR("unable to read squashfs_super_block\n");
82de647e PL	116	err = PTR_ERR(sblk);
82de647e PL	117	sblk = NULL;
0aa66619 PL	118	goto failed_mount;
	119	}
	120
4c0f0bb2 PL	121	err = -EINVAL;
4c0f0bb2 PL	122
0aa66619 PL	123	/* Check it is a SQUASHFS superblock */
	124	sb->s_magic = le32_to_cpu(sblk->s_magic);
	125	if (sb->s_magic != SQUASHFS_MAGIC) {
	126	if (!silent)
	127	ERROR("Can't find a SQUASHFS superblock on %s\n",
	128	bdevname(sb->s_bdev, b));
0aa66619 PL	129	goto failed_mount;
	130	}
	131
4c0f0bb2 PL	132	/* Check the MAJOR & MINOR versions and lookup compression type */
	133	msblk->decompressor = supported_squashfs_filesystem(
	134	le16_to_cpu(sblk->s_major),
0aa66619 PL	135	le16_to_cpu(sblk->s_minor),
0aa66619 PL	136	le16_to_cpu(sblk->compression));
4c0f0bb2	137	if (msblk->decompressor == NULL)
0aa66619 PL	138	goto failed_mount;
0aa66619 PL	139
0aa66619 PL	140	/* Check the filesystem does not extend beyond the end of the
	141	block device */
	142	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
	143	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
	144	i_size_read(sb->s_bdev->bd_inode))
	145	goto failed_mount;
	146
	147	/* Check block size for sanity */
	148	msblk->block_size = le32_to_cpu(sblk->block_size);
	149	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
	150	goto failed_mount;
	151
fffb47b8 PL	152	/*
	153	* Check the system page size is not larger than the filesystem
	154	* block size (by default 128K). This is currently not supported.
	155	*/
	156	if (PAGE_CACHE_SIZE > msblk->block_size) {
	157	ERROR("Page size > filesystem block size (%d). This is "
	158	"currently not supported!\n", msblk->block_size);
	159	goto failed_mount;
	160	}
	161
4b0180a4	162	/* Check block log for sanity */
0aa66619 PL	163	msblk->block_log = le16_to_cpu(sblk->block_log);
	164	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
	165	goto failed_mount;
	166
4b0180a4 PL	167	/* Check that block_size and block_log match */
	168	if (msblk->block_size != (1 << msblk->block_log))
	169	goto failed_mount;
	170
0aa66619 PL	171	/* Check the root inode for sanity */
	172	root_inode = le64_to_cpu(sblk->root_inode);
	173	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
	174	goto failed_mount;
	175
	176	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
	177	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
	178	msblk->inodes = le32_to_cpu(sblk->inodes);
	179	flags = le16_to_cpu(sblk->flags);
	180
	181	TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
	182	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
	183	? "un" : "");
	184	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
	185	? "un" : "");
	186	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
	187	TRACE("Block size %d\n", msblk->block_size);
	188	TRACE("Number of inodes %d\n", msblk->inodes);
	189	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
	190	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
	191	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
	192	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
	193	TRACE("sblk->fragment_table_start %llx\n",
	194	(u64) le64_to_cpu(sblk->fragment_table_start));
	195	TRACE("sblk->id_table_start %llx\n",
	196	(u64) le64_to_cpu(sblk->id_table_start));
	197
	198	sb->s_maxbytes = MAX_LFS_FILESIZE;
	199	sb->s_flags \|= MS_RDONLY;
	200	sb->s_op = &squashfs_super_ops;
	201
	202	err = -ENOMEM;
	203
	204	msblk->block_cache = squashfs_cache_init("metadata",
	205	SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
	206	if (msblk->block_cache == NULL)
	207	goto failed_mount;
	208
	209	/* Allocate read_page block */
9508c6b9 PL	210	msblk->read_page = squashfs_cache_init("data",
9508c6b9 PL	211	squashfs_max_decompressors(), msblk->block_size);
0aa66619 PL	212	if (msblk->read_page == NULL) {
	213	ERROR("Failed to allocate read_page block\n");
	214	goto failed_mount;
	215	}
	216
9508c6b9	217	msblk->stream = squashfs_decompressor_setup(sb, flags);
b7fc0ff0 PL	218	if (IS_ERR(msblk->stream)) {
	219	err = PTR_ERR(msblk->stream);
	220	msblk->stream = NULL;
	221	goto failed_mount;
	222	}
	223
76e002f7 PL	224	/* Handle xattrs */
	225	sb->s_xattr = squashfs_xattr_handlers;
	226	xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
37986f63 PL	227	if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
37986f63 PL	228	next_table = msblk->bytes_used;
76e002f7	229	goto allocate_id_index_table;
37986f63	230	}
76e002f7 PL	231
	232	/* Allocate and read xattr id lookup table */
	233	msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
	234	xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
	235	if (IS_ERR(msblk->xattr_id_table)) {
	236	ERROR("unable to read xattr id index table\n");
	237	err = PTR_ERR(msblk->xattr_id_table);
	238	msblk->xattr_id_table = NULL;
	239	if (err != -ENOTSUPP)
	240	goto failed_mount;
	241	}
37986f63	242	next_table = msblk->xattr_table;
76e002f7 PL	243
76e002f7 PL	244	allocate_id_index_table:
0aa66619 PL	245	/* Allocate and read id index table */
0aa66619 PL	246	msblk->id_table = squashfs_read_id_index_table(sb,
37986f63 PL	247	le64_to_cpu(sblk->id_table_start), next_table,
37986f63 PL	248	le16_to_cpu(sblk->no_ids));
0aa66619	249	if (IS_ERR(msblk->id_table)) {
82de647e	250	ERROR("unable to read id index table\n");
0aa66619 PL	251	err = PTR_ERR(msblk->id_table);
	252	msblk->id_table = NULL;
	253	goto failed_mount;
	254	}
d5b72ce1	255	next_table = le64_to_cpu(msblk->id_table[0]);
0aa66619	256
76e002f7 PL	257	/* Handle inode lookup table */
	258	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
	259	if (lookup_table_start == SQUASHFS_INVALID_BLK)
	260	goto handle_fragments;
	261
	262	/* Allocate and read inode lookup table */
	263	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
ac51a0a7	264	lookup_table_start, next_table, msblk->inodes);
76e002f7 PL	265	if (IS_ERR(msblk->inode_lookup_table)) {
	266	ERROR("unable to read inode lookup table\n");
	267	err = PTR_ERR(msblk->inode_lookup_table);
	268	msblk->inode_lookup_table = NULL;
	269	goto failed_mount;
	270	}
d5b72ce1	271	next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
76e002f7 PL	272
	273	sb->s_export_op = &squashfs_export_ops;
	274
	275	handle_fragments:
0aa66619 PL	276	fragments = le32_to_cpu(sblk->fragments);
0aa66619 PL	277	if (fragments == 0)
1094a4a6	278	goto check_directory_table;
0aa66619 PL	279
	280	msblk->fragment_cache = squashfs_cache_init("fragment",
	281	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
	282	if (msblk->fragment_cache == NULL) {
	283	err = -ENOMEM;
	284	goto failed_mount;
	285	}
	286
	287	/* Allocate and read fragment index table */
	288	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
1cac63cc	289	le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
0aa66619	290	if (IS_ERR(msblk->fragment_index)) {
82de647e	291	ERROR("unable to read fragment index table\n");
0aa66619 PL	292	err = PTR_ERR(msblk->fragment_index);
	293	msblk->fragment_index = NULL;
	294	goto failed_mount;
	295	}
d5b72ce1	296	next_table = le64_to_cpu(msblk->fragment_index[0]);
0aa66619	297
1094a4a6 PL	298	check_directory_table:
1094a4a6 PL	299	/* Sanity check directory_table */
cc37f75a	300	if (msblk->directory_table > next_table) {
1094a4a6 PL	301	err = -EINVAL;
	302	goto failed_mount;
	303	}
	304
	305	/* Sanity check inode_table */
	306	if (msblk->inode_table >= msblk->directory_table) {
	307	err = -EINVAL;
	308	goto failed_mount;
	309	}
	310
	311	/* allocate root */
0aa66619 PL	312	root = new_inode(sb);
	313	if (!root) {
	314	err = -ENOMEM;
	315	goto failed_mount;
	316	}
	317
	318	err = squashfs_read_inode(root, root_inode);
	319	if (err) {
1cb08e97 PL	320	make_bad_inode(root);
1cb08e97 PL	321	iput(root);
0aa66619 PL	322	goto failed_mount;
	323	}
	324	insert_inode_hash(root);
	325
48fde701	326	sb->s_root = d_make_root(root);
0aa66619 PL	327	if (sb->s_root == NULL) {
	328	ERROR("Root inode create failed\n");
	329	err = -ENOMEM;
0aa66619 PL	330	goto failed_mount;
	331	}
	332
	333	TRACE("Leaving squashfs_fill_super\n");
	334	kfree(sblk);
	335	return 0;
	336
	337	failed_mount:
	338	squashfs_cache_delete(msblk->block_cache);
	339	squashfs_cache_delete(msblk->fragment_cache);
	340	squashfs_cache_delete(msblk->read_page);
9508c6b9	341	squashfs_decompressor_destroy(msblk);
0aa66619 PL	342	kfree(msblk->inode_lookup_table);
	343	kfree(msblk->fragment_index);
	344	kfree(msblk->id_table);
4b5397dc	345	kfree(msblk->xattr_id_table);
0aa66619 PL	346	kfree(sb->s_fs_info);
	347	sb->s_fs_info = NULL;
	348	kfree(sblk);
	349	return err;
0aa66619 PL	350	}
	351
	352
	353	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
	354	{
	355	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
2fc7f562	356	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
0aa66619 PL	357
	358	TRACE("Entered squashfs_statfs\n");
	359
	360	buf->f_type = SQUASHFS_MAGIC;
	361	buf->f_bsize = msblk->block_size;
	362	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
	363	buf->f_bfree = buf->f_bavail = 0;
	364	buf->f_files = msblk->inodes;
	365	buf->f_ffree = 0;
	366	buf->f_namelen = SQUASHFS_NAME_LEN;
2fc7f562 CL	367	buf->f_fsid.val[0] = (u32)id;
2fc7f562 CL	368	buf->f_fsid.val[1] = (u32)(id >> 32);
0aa66619 PL	369
	370	return 0;
	371	}
	372
	373
	374	static int squashfs_remount(struct super_block sb, int flags, char *data)
	375	{
02b9984d	376	sync_filesystem(sb);
0aa66619 PL	377	*flags \|= MS_RDONLY;
	378	return 0;
	379	}
	380
	381
	382	static void squashfs_put_super(struct super_block *sb)
	383	{
	384	if (sb->s_fs_info) {
	385	struct squashfs_sb_info *sbi = sb->s_fs_info;
	386	squashfs_cache_delete(sbi->block_cache);
	387	squashfs_cache_delete(sbi->fragment_cache);
	388	squashfs_cache_delete(sbi->read_page);
9508c6b9	389	squashfs_decompressor_destroy(sbi);
0aa66619 PL	390	kfree(sbi->id_table);
	391	kfree(sbi->fragment_index);
	392	kfree(sbi->meta_index);
370ec3d1	393	kfree(sbi->inode_lookup_table);
4b5397dc	394	kfree(sbi->xattr_id_table);
0aa66619 PL	395	kfree(sb->s_fs_info);
	396	sb->s_fs_info = NULL;
	397	}
	398	}
	399
	400
003a3194 PL	401	static struct dentry squashfs_mount(struct file_system_type fs_type,
003a3194 PL	402	int flags, const char dev_name, void data)
0aa66619	403	{
152a0836	404	return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
0aa66619 PL	405	}
	406
	407
	408	static struct kmem_cache *squashfs_inode_cachep;
	409
	410
	411	static void init_once(void *foo)
	412	{
	413	struct squashfs_inode_info *ei = foo;
	414
	415	inode_init_once(&ei->vfs_inode);
	416	}
	417
	418
	419	static int __init init_inodecache(void)
	420	{
	421	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
	422	sizeof(struct squashfs_inode_info), 0,
	423	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT, init_once);
	424
	425	return squashfs_inode_cachep ? 0 : -ENOMEM;
	426	}
	427
	428
	429	static void destroy_inodecache(void)
	430	{
8c0a8537 KS	431	/*
	432	* Make sure all delayed rcu free inodes are flushed before we
	433	* destroy cache.
	434	*/
	435	rcu_barrier();
0aa66619 PL	436	kmem_cache_destroy(squashfs_inode_cachep);
	437	}
	438
	439
	440	static int __init init_squashfs_fs(void)
	441	{
	442	int err = init_inodecache();
	443
	444	if (err)
	445	return err;
	446
	447	err = register_filesystem(&squashfs_fs_type);
	448	if (err) {
	449	destroy_inodecache();
	450	return err;
	451	}
	452
c811f5f4	453	pr_info("version 4.0 (2009/01/31) Phillip Lougher\n");
0aa66619 PL	454
	455	return 0;
	456	}
	457
	458
	459	static void __exit exit_squashfs_fs(void)
	460	{
	461	unregister_filesystem(&squashfs_fs_type);
	462	destroy_inodecache();
	463	}
	464
	465
	466	static struct inode squashfs_alloc_inode(struct super_block sb)
	467	{
	468	struct squashfs_inode_info *ei =
	469	kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
	470
	471	return ei ? &ei->vfs_inode : NULL;
	472	}
	473
	474
fa0d7e3d	475	static void squashfs_i_callback(struct rcu_head *head)
0aa66619	476	{
fa0d7e3d	477	struct inode *inode = container_of(head, struct inode, i_rcu);
0aa66619 PL	478	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
	479	}
	480
fa0d7e3d NP	481	static void squashfs_destroy_inode(struct inode *inode)
	482	{
	483	call_rcu(&inode->i_rcu, squashfs_i_callback);
	484	}
	485
0aa66619 PL	486
	487	static struct file_system_type squashfs_fs_type = {
	488	.owner = THIS_MODULE,
	489	.name = "squashfs",
152a0836	490	.mount = squashfs_mount,
0aa66619 PL	491	.kill_sb = kill_block_super,
	492	.fs_flags = FS_REQUIRES_DEV
	493	};
3e64fe5b	494	MODULE_ALIAS_FS("squashfs");
0aa66619	495
b87221de	496	static const struct super_operations squashfs_super_ops = {
0aa66619 PL	497	.alloc_inode = squashfs_alloc_inode,
	498	.destroy_inode = squashfs_destroy_inode,
	499	.statfs = squashfs_statfs,
	500	.put_super = squashfs_put_super,
	501	.remount_fs = squashfs_remount
	502	};
	503
	504	module_init(init_squashfs_fs);
	505	module_exit(exit_squashfs_fs);
	506	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
d7f2ff67	507	MODULE_AUTHOR("Phillip Lougher <[email protected]>");
0aa66619	508	MODULE_LICENSE("GPL");