[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.
 */

#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"

static struct file_system_type squashfs_fs_type;
static const struct super_operations squashfs_super_ops;

static int supported_squashfs_filesystem(short major, short minor, short comp)
{
	if (major < SQUASHFS_MAJOR) {
		ERROR("Major/Minor mismatch, older Squashfs %d.%d "
			"filesystems are unsupported\n", major, minor);
		return -EINVAL;
	} 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 -EINVAL;
	}

	if (comp != ZLIB_COMPRESSION)
		return -EINVAL;

	return 0;
}


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;

	msblk->stream = squashfs_zlib_init();
	if (msblk->stream == NULL)
		goto failure;

	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;
	}

	/* 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));
		err = -EINVAL;
		goto failed_mount;
	}

	/* Check the MAJOR & MINOR versions and compression type */
	err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
			le16_to_cpu(sblk->s_minor),
			le16_to_cpu(sblk->compression));
	if (err < 0)
		goto failed_mount;

	err = -EINVAL;

	/*
	 * 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->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_zlib_free(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:
	squashfs_zlib_free(msblk->stream);
	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_zlib_free(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 <[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
	5	* Phillip Lougher <[email protected]>
	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"
	44
	45	static struct file_system_type squashfs_fs_type;
b87221de	46	static const struct super_operations squashfs_super_ops;
0aa66619 PL	47
	48	static int supported_squashfs_filesystem(short major, short minor, short comp)
	49	{
	50	if (major < SQUASHFS_MAJOR) {
	51	ERROR("Major/Minor mismatch, older Squashfs %d.%d "
	52	"filesystems are unsupported\n", major, minor);
	53	return -EINVAL;
	54	} else if (major > SQUASHFS_MAJOR \|\| minor > SQUASHFS_MINOR) {
	55	ERROR("Major/Minor mismatch, trying to mount newer "
	56	"%d.%d filesystem\n", major, minor);
	57	ERROR("Please update your kernel\n");
	58	return -EINVAL;
	59	}
	60
	61	if (comp != ZLIB_COMPRESSION)
	62	return -EINVAL;
	63
	64	return 0;
	65	}
	66
	67
	68	static int squashfs_fill_super(struct super_block sb, void data, int silent)
	69	{
	70	struct squashfs_sb_info *msblk;
	71	struct squashfs_super_block *sblk = NULL;
	72	char b[BDEVNAME_SIZE];
	73	struct inode *root;
	74	long long root_inode;
	75	unsigned short flags;
	76	unsigned int fragments;
	77	u64 lookup_table_start;
	78	int err;
	79
	80	TRACE("Entered squashfs_fill_superblock\n");
	81
	82	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
	83	if (sb->s_fs_info == NULL) {
	84	ERROR("Failed to allocate squashfs_sb_info\n");
	85	return -ENOMEM;
	86	}
	87	msblk = sb->s_fs_info;
	88
f1a40359 PL	89	msblk->stream = squashfs_zlib_init();
f1a40359 PL	90	if (msblk->stream == NULL)
0aa66619	91	goto failure;
0aa66619 PL	92
	93	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
	94	if (sblk == NULL) {
	95	ERROR("Failed to allocate squashfs_super_block\n");
	96	goto failure;
	97	}
	98
	99	msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
	100	msblk->devblksize_log2 = ffz(~msblk->devblksize);
	101
	102	mutex_init(&msblk->read_data_mutex);
	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);
	112	err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));
	113
	114	if (err < 0) {
	115	ERROR("unable to read squashfs_super_block\n");
	116	goto failed_mount;
	117	}
	118
	119	/* Check it is a SQUASHFS superblock */
	120	sb->s_magic = le32_to_cpu(sblk->s_magic);
	121	if (sb->s_magic != SQUASHFS_MAGIC) {
	122	if (!silent)
	123	ERROR("Can't find a SQUASHFS superblock on %s\n",
	124	bdevname(sb->s_bdev, b));
	125	err = -EINVAL;
	126	goto failed_mount;
	127	}
	128
	129	/* Check the MAJOR & MINOR versions and compression type */
	130	err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
	131	le16_to_cpu(sblk->s_minor),
	132	le16_to_cpu(sblk->compression));
	133	if (err < 0)
	134	goto failed_mount;
	135
	136	err = -EINVAL;
	137
	138	/*
	139	* Check if there's xattrs in the filesystem. These are not
	140	* supported in this version, so warn that they will be ignored.
	141	*/
	142	if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
	143	ERROR("Xattrs in filesystem, these will be ignored\n");
	144
	145	/* Check the filesystem does not extend beyond the end of the
	146	block device */
	147	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
	148	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
	149	i_size_read(sb->s_bdev->bd_inode))
	150	goto failed_mount;
	151
	152	/* Check block size for sanity */
	153	msblk->block_size = le32_to_cpu(sblk->block_size);
	154	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
	155	goto failed_mount;
156
fffb47b8 PL	157	/*
	158	* Check the system page size is not larger than the filesystem
	159	* block size (by default 128K). This is currently not supported.
	160	*/
	161	if (PAGE_CACHE_SIZE > msblk->block_size) {
	162	ERROR("Page size > filesystem block size (%d). This is "
	163	"currently not supported!\n", msblk->block_size);
	164	goto failed_mount;
	165	}
	166
0aa66619 PL	167	msblk->block_log = le16_to_cpu(sblk->block_log);
	168	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
	169	goto failed_mount;
	170
	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 */
	210	msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
	211	if (msblk->read_page == NULL) {
	212	ERROR("Failed to allocate read_page block\n");
	213	goto failed_mount;
	214	}
	215
	216	/* Allocate and read id index table */
	217	msblk->id_table = squashfs_read_id_index_table(sb,
	218	le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
	219	if (IS_ERR(msblk->id_table)) {
	220	err = PTR_ERR(msblk->id_table);
	221	msblk->id_table = NULL;
	222	goto failed_mount;
	223	}
	224
	225	fragments = le32_to_cpu(sblk->fragments);
	226	if (fragments == 0)
	227	goto allocate_lookup_table;
	228
	229	msblk->fragment_cache = squashfs_cache_init("fragment",
	230	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
231	if (msblk->fragment_cache == NULL) {
232	err = -ENOMEM;
233	goto failed_mount;
234	}
235
236	/* Allocate and read fragment index table */
237	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
238	le64_to_cpu(sblk->fragment_table_start), fragments);
239	if (IS_ERR(msblk->fragment_index)) {
240	err = PTR_ERR(msblk->fragment_index);
241	msblk->fragment_index = NULL;
242	goto failed_mount;
243	}
244
245	allocate_lookup_table:
246	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
247	if (lookup_table_start == SQUASHFS_INVALID_BLK)
248	goto allocate_root;
249
250	/* Allocate and read inode lookup table */
251	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
252	lookup_table_start, msblk->inodes);
253	if (IS_ERR(msblk->inode_lookup_table)) {
254	err = PTR_ERR(msblk->inode_lookup_table);
255	msblk->inode_lookup_table = NULL;
256	goto failed_mount;
257	}
258
259	sb->s_export_op = &squashfs_export_ops;
260
261	allocate_root:
262	root = new_inode(sb);
263	if (!root) {
264	err = -ENOMEM;
265	goto failed_mount;
266	}
267
268	err = squashfs_read_inode(root, root_inode);
269	if (err) {
270	iget_failed(root);
271	goto failed_mount;
272	}
273	insert_inode_hash(root);
274
275	sb->s_root = d_alloc_root(root);
276	if (sb->s_root == NULL) {
277	ERROR("Root inode create failed\n");
278	err = -ENOMEM;
279	iput(root);
280	goto failed_mount;
281	}
282
283	TRACE("Leaving squashfs_fill_super\n");
284	kfree(sblk);
285	return 0;
286
287	failed_mount:
288	squashfs_cache_delete(msblk->block_cache);
289	squashfs_cache_delete(msblk->fragment_cache);
290	squashfs_cache_delete(msblk->read_page);
f1a40359	291	squashfs_zlib_free(msblk->stream);
0aa66619 PL	292	kfree(msblk->inode_lookup_table);
	293	kfree(msblk->fragment_index);
	294	kfree(msblk->id_table);
0aa66619 PL	295	kfree(sb->s_fs_info);
	296	sb->s_fs_info = NULL;
	297	kfree(sblk);
	298	return err;
	299
	300	failure:
f1a40359	301	squashfs_zlib_free(msblk->stream);
0aa66619 PL	302	kfree(sb->s_fs_info);
	303	sb->s_fs_info = NULL;
	304	return -ENOMEM;
	305	}
	306
	307
	308	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
	309	{
	310	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
2fc7f562	311	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
0aa66619 PL	312
	313	TRACE("Entered squashfs_statfs\n");
	314
	315	buf->f_type = SQUASHFS_MAGIC;
	316	buf->f_bsize = msblk->block_size;
	317	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
	318	buf->f_bfree = buf->f_bavail = 0;
	319	buf->f_files = msblk->inodes;
	320	buf->f_ffree = 0;
	321	buf->f_namelen = SQUASHFS_NAME_LEN;
2fc7f562 CL	322	buf->f_fsid.val[0] = (u32)id;
2fc7f562 CL	323	buf->f_fsid.val[1] = (u32)(id >> 32);
0aa66619 PL	324
	325	return 0;
	326	}
	327
	328
	329	static int squashfs_remount(struct super_block sb, int flags, char *data)
	330	{
	331	*flags \|= MS_RDONLY;
	332	return 0;
	333	}
	334
	335
	336	static void squashfs_put_super(struct super_block *sb)
	337	{
6cfd0148 CH	338	lock_kernel();
6cfd0148 CH	339
0aa66619 PL	340	if (sb->s_fs_info) {
	341	struct squashfs_sb_info *sbi = sb->s_fs_info;
	342	squashfs_cache_delete(sbi->block_cache);
	343	squashfs_cache_delete(sbi->fragment_cache);
	344	squashfs_cache_delete(sbi->read_page);
f1a40359	345	squashfs_zlib_free(sbi->stream);
0aa66619 PL	346	kfree(sbi->id_table);
	347	kfree(sbi->fragment_index);
	348	kfree(sbi->meta_index);
0aa66619 PL	349	kfree(sb->s_fs_info);
	350	sb->s_fs_info = NULL;
	351	}
6cfd0148 CH	352
6cfd0148 CH	353	unlock_kernel();
0aa66619 PL	354	}
	355
	356
	357	static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
	358	const char dev_name, void data,
	359	struct vfsmount *mnt)
	360	{
	361	return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
	362	mnt);
	363	}
	364
	365
	366	static struct kmem_cache *squashfs_inode_cachep;
	367
	368
	369	static void init_once(void *foo)
	370	{
	371	struct squashfs_inode_info *ei = foo;
	372
	373	inode_init_once(&ei->vfs_inode);
	374	}
	375
	376
	377	static int __init init_inodecache(void)
	378	{
	379	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
	380	sizeof(struct squashfs_inode_info), 0,
	381	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT, init_once);
	382
	383	return squashfs_inode_cachep ? 0 : -ENOMEM;
	384	}
	385
	386
	387	static void destroy_inodecache(void)
	388	{
	389	kmem_cache_destroy(squashfs_inode_cachep);
	390	}
	391
	392
	393	static int __init init_squashfs_fs(void)
	394	{
	395	int err = init_inodecache();
	396
	397	if (err)
	398	return err;
	399
	400	err = register_filesystem(&squashfs_fs_type);
	401	if (err) {
	402	destroy_inodecache();
	403	return err;
	404	}
	405
118e1ef6	406	printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
0aa66619 PL	407	"Phillip Lougher\n");
	408
	409	return 0;
	410	}
	411
	412
	413	static void __exit exit_squashfs_fs(void)
	414	{
	415	unregister_filesystem(&squashfs_fs_type);
	416	destroy_inodecache();
	417	}
	418
	419
	420	static struct inode squashfs_alloc_inode(struct super_block sb)
	421	{
	422	struct squashfs_inode_info *ei =
	423	kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
	424
	425	return ei ? &ei->vfs_inode : NULL;
	426	}
	427
	428
	429	static void squashfs_destroy_inode(struct inode *inode)
	430	{
	431	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
	432	}
	433
	434
	435	static struct file_system_type squashfs_fs_type = {
	436	.owner = THIS_MODULE,
	437	.name = "squashfs",
	438	.get_sb = squashfs_get_sb,
	439	.kill_sb = kill_block_super,
	440	.fs_flags = FS_REQUIRES_DEV
	441	};
	442
b87221de	443	static const struct super_operations squashfs_super_ops = {
0aa66619 PL	444	.alloc_inode = squashfs_alloc_inode,
	445	.destroy_inode = squashfs_destroy_inode,
	446	.statfs = squashfs_statfs,
	447	.put_super = squashfs_put_super,
	448	.remount_fs = squashfs_remount
	449	};
	450
	451	module_init(init_squashfs_fs);
	452	module_exit(exit_squashfs_fs);
	453	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
	454	MODULE_AUTHOR("Phillip Lougher <[email protected]>");
	455	MODULE_LICENSE("GPL");