[mirror_ubuntu-hirsute-kernel.git] / fs / squashfs / super.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
 * Phillip Lougher <phillip@squashfs.org.uk>
 *
 * 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/fs_context.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(
	struct fs_context *fc,
	short major, short minor, short id)
{
	const struct squashfs_decompressor *decompressor;

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

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

	return decompressor;
}


static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
	struct squashfs_sb_info *msblk;
	struct squashfs_super_block *sblk = NULL;
	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)) {
		errorf(fc, "unable to read squashfs_super_block");
		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 (!(fc->sb_flags & SB_SILENT))
			errorf(fc, "Can't find a SQUASHFS superblock on %pg",
			       sb->s_bdev);
		goto failed_mount;
	}

	/* Check the MAJOR & MINOR versions and lookup compression type */
	msblk->decompressor = supported_squashfs_filesystem(
			fc,
			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 insanity;

	/*
	 * Check the system page size is not larger than the filesystem
	 * block size (by default 128K).  This is currently not supported.
	 */
	if (PAGE_SIZE > msblk->block_size) {
		errorf(fc, "Page size > filesystem block size (%d).  This is "
		       "currently not supported!", 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 insanity;

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

	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);
	msblk->fragments = le32_to_cpu(sblk->fragments);
	msblk->ids = le16_to_cpu(sblk->no_ids);
	flags = le16_to_cpu(sblk->flags);

	TRACE("Found valid superblock on %pg\n", sb->s_bdev);
	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", msblk->fragments);
	TRACE("Number of ids %d\n", msblk->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_time_min = 0;
	sb->s_time_max = U32_MAX;
	sb->s_flags |= SB_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) {
		errorf(fc, "Failed to allocate read_page block");
		goto failed_mount;
	}

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

	/* 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)) {
		errorf(fc, "unable to read xattr id index table");
		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, msblk->ids);
	if (IS_ERR(msblk->id_table)) {
		errorf(fc, "unable to read id index table");
		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)) {
		errorf(fc, "unable to read inode lookup table");
		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 = msblk->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)) {
		errorf(fc, "unable to read fragment index table");
		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 insanity;
	}

	/* Sanity check inode_table */
	if (msblk->inode_table >= msblk->directory_table) {
		err = -EINVAL;
		goto insanity;
	}

	/* 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;

insanity:
	errorf(fc, "squashfs image failed sanity check");
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_get_tree(struct fs_context *fc)
{
	return get_tree_bdev(fc, squashfs_fill_super);
}

static int squashfs_reconfigure(struct fs_context *fc)
{
	sync_filesystem(fc->root->d_sb);
	fc->sb_flags |= SB_RDONLY;
	return 0;
}

static const struct fs_context_operations squashfs_context_ops = {
	.get_tree	= squashfs_get_tree,
	.reconfigure	= squashfs_reconfigure,
};

static int squashfs_init_fs_context(struct fs_context *fc)
{
	fc->ops = &squashfs_context_ops;
	return 0;
}

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 = u64_to_fsid(id);

	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 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|SLAB_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_free_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",
	.init_fs_context = squashfs_init_fs_context,
	.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,
	.free_inode = squashfs_free_inode,
	.statfs = squashfs_statfs,
	.put_super = squashfs_put_super,
};

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
	1	// SPDX-License-Identifier: GPL-2.0-or-later
	2	/*
	3	* Squashfs - a compressed read only filesystem for Linux
	4	*
	5	* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
	6	* Phillip Lougher <phillip@squashfs.org.uk>
	7	*
	8	* super.c
	9	*/
	10
	11	/*
	12	* This file implements code to read the superblock, read and initialise
	13	* in-memory structures at mount time, and all the VFS glue code to register
	14	* the filesystem.
	15	*/
	16
	17	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	18
	19	#include <linux/fs.h>
	20	#include <linux/fs_context.h>
	21	#include <linux/vfs.h>
	22	#include <linux/slab.h>
	23	#include <linux/mutex.h>
	24	#include <linux/pagemap.h>
	25	#include <linux/init.h>
	26	#include <linux/module.h>
	27	#include <linux/magic.h>
	28	#include <linux/xattr.h>
	29
	30	#include "squashfs_fs.h"
	31	#include "squashfs_fs_sb.h"
	32	#include "squashfs_fs_i.h"
	33	#include "squashfs.h"
	34	#include "decompressor.h"
	35	#include "xattr.h"
	36
	37	static struct file_system_type squashfs_fs_type;
	38	static const struct super_operations squashfs_super_ops;
	39
	40	static const struct squashfs_decompressor *supported_squashfs_filesystem(
	41	struct fs_context *fc,
	42	short major, short minor, short id)
	43	{
	44	const struct squashfs_decompressor *decompressor;
	45
	46	if (major < SQUASHFS_MAJOR) {
	47	errorf(fc, "Major/Minor mismatch, older Squashfs %d.%d "
	48	"filesystems are unsupported", major, minor);
	49	return NULL;
	50	} else if (major > SQUASHFS_MAJOR \|\| minor > SQUASHFS_MINOR) {
	51	errorf(fc, "Major/Minor mismatch, trying to mount newer "
	52	"%d.%d filesystem", major, minor);
	53	errorf(fc, "Please update your kernel");
	54	return NULL;
	55	}
	56
	57	decompressor = squashfs_lookup_decompressor(id);
	58	if (!decompressor->supported) {
	59	errorf(fc, "Filesystem uses \"%s\" compression. This is not supported",
	60	decompressor->name);
	61	return NULL;
	62	}
	63
	64	return decompressor;
	65	}
	66
	67
	68	static int squashfs_fill_super(struct super_block sb, struct fs_context fc)
	69	{
	70	struct squashfs_sb_info *msblk;
	71	struct squashfs_super_block *sblk = NULL;
	72	struct inode *root;
	73	long long root_inode;
	74	unsigned short flags;
	75	unsigned int fragments;
	76	u64 lookup_table_start, xattr_id_table_start, next_table;
	77	int err;
	78
	79	TRACE("Entered squashfs_fill_superblock\n");
	80
	81	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
	82	if (sb->s_fs_info == NULL) {
	83	ERROR("Failed to allocate squashfs_sb_info\n");
	84	return -ENOMEM;
	85	}
	86	msblk = sb->s_fs_info;
	87
	88	msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
	89	msblk->devblksize_log2 = ffz(~msblk->devblksize);
	90
	91	mutex_init(&msblk->meta_index_mutex);
	92
	93	/*
	94	* msblk->bytes_used is checked in squashfs_read_table to ensure reads
	95	* are not beyond filesystem end. But as we're using
	96	* squashfs_read_table here to read the superblock (including the value
	97	* of bytes_used) we need to set it to an initial sensible dummy value
	98	*/
	99	msblk->bytes_used = sizeof(*sblk);
	100	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
	101
	102	if (IS_ERR(sblk)) {
	103	errorf(fc, "unable to read squashfs_super_block");
	104	err = PTR_ERR(sblk);
	105	sblk = NULL;
	106	goto failed_mount;
	107	}
	108
	109	err = -EINVAL;
	110
	111	/* Check it is a SQUASHFS superblock */
	112	sb->s_magic = le32_to_cpu(sblk->s_magic);
	113	if (sb->s_magic != SQUASHFS_MAGIC) {
	114	if (!(fc->sb_flags & SB_SILENT))
	115	errorf(fc, "Can't find a SQUASHFS superblock on %pg",
	116	sb->s_bdev);
	117	goto failed_mount;
	118	}
	119
	120	/* Check the MAJOR & MINOR versions and lookup compression type */
	121	msblk->decompressor = supported_squashfs_filesystem(
	122	fc,
	123	le16_to_cpu(sblk->s_major),
	124	le16_to_cpu(sblk->s_minor),
	125	le16_to_cpu(sblk->compression));
	126	if (msblk->decompressor == NULL)
	127	goto failed_mount;
	128
	129	/* Check the filesystem does not extend beyond the end of the
	130	block device */
	131	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
	132	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
	133	i_size_read(sb->s_bdev->bd_inode))
	134	goto failed_mount;
	135
	136	/* Check block size for sanity */
	137	msblk->block_size = le32_to_cpu(sblk->block_size);
	138	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
	139	goto insanity;
	140
	141	/*
	142	* Check the system page size is not larger than the filesystem
	143	* block size (by default 128K). This is currently not supported.
	144	*/
	145	if (PAGE_SIZE > msblk->block_size) {
	146	errorf(fc, "Page size > filesystem block size (%d). This is "
	147	"currently not supported!", msblk->block_size);
	148	goto failed_mount;
	149	}
	150
	151	/* Check block log for sanity */
	152	msblk->block_log = le16_to_cpu(sblk->block_log);
	153	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
	154	goto failed_mount;
	155
	156	/* Check that block_size and block_log match */
	157	if (msblk->block_size != (1 << msblk->block_log))
	158	goto insanity;
	159
	160	/* Check the root inode for sanity */
	161	root_inode = le64_to_cpu(sblk->root_inode);
	162	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
	163	goto insanity;
	164
	165	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
	166	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
	167	msblk->inodes = le32_to_cpu(sblk->inodes);
	168	msblk->fragments = le32_to_cpu(sblk->fragments);
	169	msblk->ids = le16_to_cpu(sblk->no_ids);
	170	flags = le16_to_cpu(sblk->flags);
	171
	172	TRACE("Found valid superblock on %pg\n", sb->s_bdev);
	173	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
	174	? "un" : "");
	175	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
	176	? "un" : "");
	177	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
	178	TRACE("Block size %d\n", msblk->block_size);
	179	TRACE("Number of inodes %d\n", msblk->inodes);
	180	TRACE("Number of fragments %d\n", msblk->fragments);
	181	TRACE("Number of ids %d\n", msblk->ids);
	182	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
	183	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
	184	TRACE("sblk->fragment_table_start %llx\n",
	185	(u64) le64_to_cpu(sblk->fragment_table_start));
	186	TRACE("sblk->id_table_start %llx\n",
	187	(u64) le64_to_cpu(sblk->id_table_start));
	188
	189	sb->s_maxbytes = MAX_LFS_FILESIZE;
	190	sb->s_time_min = 0;
	191	sb->s_time_max = U32_MAX;
	192	sb->s_flags \|= SB_RDONLY;
	193	sb->s_op = &squashfs_super_ops;
	194
	195	err = -ENOMEM;
	196
	197	msblk->block_cache = squashfs_cache_init("metadata",
	198	SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
	199	if (msblk->block_cache == NULL)
	200	goto failed_mount;
	201
	202	/* Allocate read_page block */
	203	msblk->read_page = squashfs_cache_init("data",
	204	squashfs_max_decompressors(), msblk->block_size);
	205	if (msblk->read_page == NULL) {
	206	errorf(fc, "Failed to allocate read_page block");
	207	goto failed_mount;
	208	}
	209
	210	msblk->stream = squashfs_decompressor_setup(sb, flags);
	211	if (IS_ERR(msblk->stream)) {
	212	err = PTR_ERR(msblk->stream);
	213	msblk->stream = NULL;
	214	goto insanity;
	215	}
	216
	217	/* Handle xattrs */
	218	sb->s_xattr = squashfs_xattr_handlers;
	219	xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
	220	if (xattr_id_table_start == SQUASHFS_INVALID_BLK) {
	221	next_table = msblk->bytes_used;
	222	goto allocate_id_index_table;
	223	}
	224
	225	/* Allocate and read xattr id lookup table */
	226	msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
	227	xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
	228	if (IS_ERR(msblk->xattr_id_table)) {
	229	errorf(fc, "unable to read xattr id index table");
	230	err = PTR_ERR(msblk->xattr_id_table);
	231	msblk->xattr_id_table = NULL;
	232	if (err != -ENOTSUPP)
	233	goto failed_mount;
	234	}
	235	next_table = msblk->xattr_table;
	236
	237	allocate_id_index_table:
	238	/* Allocate and read id index table */
	239	msblk->id_table = squashfs_read_id_index_table(sb,
	240	le64_to_cpu(sblk->id_table_start), next_table, msblk->ids);
	241	if (IS_ERR(msblk->id_table)) {
	242	errorf(fc, "unable to read id index table");
	243	err = PTR_ERR(msblk->id_table);
	244	msblk->id_table = NULL;
	245	goto failed_mount;
	246	}
	247	next_table = le64_to_cpu(msblk->id_table[0]);
	248
	249	/* Handle inode lookup table */
	250	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
	251	if (lookup_table_start == SQUASHFS_INVALID_BLK)
	252	goto handle_fragments;
	253
	254	/* Allocate and read inode lookup table */
	255	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
	256	lookup_table_start, next_table, msblk->inodes);
	257	if (IS_ERR(msblk->inode_lookup_table)) {
	258	errorf(fc, "unable to read inode lookup table");
	259	err = PTR_ERR(msblk->inode_lookup_table);
	260	msblk->inode_lookup_table = NULL;
	261	goto failed_mount;
	262	}
	263	next_table = le64_to_cpu(msblk->inode_lookup_table[0]);
	264
	265	sb->s_export_op = &squashfs_export_ops;
	266
	267	handle_fragments:
	268	fragments = msblk->fragments;
	269	if (fragments == 0)
	270	goto check_directory_table;
	271
	272	msblk->fragment_cache = squashfs_cache_init("fragment",
	273	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
	274	if (msblk->fragment_cache == NULL) {
	275	err = -ENOMEM;
	276	goto failed_mount;
	277	}
	278
	279	/* Allocate and read fragment index table */
	280	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
	281	le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
	282	if (IS_ERR(msblk->fragment_index)) {
	283	errorf(fc, "unable to read fragment index table");
	284	err = PTR_ERR(msblk->fragment_index);
	285	msblk->fragment_index = NULL;
	286	goto failed_mount;
	287	}
	288	next_table = le64_to_cpu(msblk->fragment_index[0]);
	289
	290	check_directory_table:
	291	/* Sanity check directory_table */
	292	if (msblk->directory_table > next_table) {
	293	err = -EINVAL;
	294	goto insanity;
	295	}
	296
	297	/* Sanity check inode_table */
	298	if (msblk->inode_table >= msblk->directory_table) {
	299	err = -EINVAL;
	300	goto insanity;
	301	}
	302
	303	/* allocate root */
	304	root = new_inode(sb);
	305	if (!root) {
	306	err = -ENOMEM;
	307	goto failed_mount;
	308	}
	309
	310	err = squashfs_read_inode(root, root_inode);
	311	if (err) {
	312	make_bad_inode(root);
	313	iput(root);
	314	goto failed_mount;
	315	}
	316	insert_inode_hash(root);
	317
	318	sb->s_root = d_make_root(root);
	319	if (sb->s_root == NULL) {
	320	ERROR("Root inode create failed\n");
	321	err = -ENOMEM;
	322	goto failed_mount;
	323	}
	324
	325	TRACE("Leaving squashfs_fill_super\n");
	326	kfree(sblk);
	327	return 0;
	328
	329	insanity:
	330	errorf(fc, "squashfs image failed sanity check");
	331	failed_mount:
	332	squashfs_cache_delete(msblk->block_cache);
	333	squashfs_cache_delete(msblk->fragment_cache);
	334	squashfs_cache_delete(msblk->read_page);
	335	squashfs_decompressor_destroy(msblk);
	336	kfree(msblk->inode_lookup_table);
	337	kfree(msblk->fragment_index);
	338	kfree(msblk->id_table);
	339	kfree(msblk->xattr_id_table);
	340	kfree(sb->s_fs_info);
	341	sb->s_fs_info = NULL;
	342	kfree(sblk);
	343	return err;
	344	}
	345
	346	static int squashfs_get_tree(struct fs_context *fc)
	347	{
	348	return get_tree_bdev(fc, squashfs_fill_super);
	349	}
	350
	351	static int squashfs_reconfigure(struct fs_context *fc)
	352	{
	353	sync_filesystem(fc->root->d_sb);
	354	fc->sb_flags \|= SB_RDONLY;
	355	return 0;
	356	}
	357
	358	static const struct fs_context_operations squashfs_context_ops = {
	359	.get_tree = squashfs_get_tree,
	360	.reconfigure = squashfs_reconfigure,
	361	};
	362
	363	static int squashfs_init_fs_context(struct fs_context *fc)
	364	{
	365	fc->ops = &squashfs_context_ops;
	366	return 0;
	367	}
	368
	369	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
	370	{
	371	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
	372	u64 id = huge_encode_dev(dentry->d_sb->s_bdev->bd_dev);
	373
	374	TRACE("Entered squashfs_statfs\n");
	375
	376	buf->f_type = SQUASHFS_MAGIC;
	377	buf->f_bsize = msblk->block_size;
	378	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
	379	buf->f_bfree = buf->f_bavail = 0;
	380	buf->f_files = msblk->inodes;
	381	buf->f_ffree = 0;
	382	buf->f_namelen = SQUASHFS_NAME_LEN;
	383	buf->f_fsid = u64_to_fsid(id);
	384
	385	return 0;
	386	}
	387
	388
	389	static void squashfs_put_super(struct super_block *sb)
	390	{
	391	if (sb->s_fs_info) {
	392	struct squashfs_sb_info *sbi = sb->s_fs_info;
	393	squashfs_cache_delete(sbi->block_cache);
	394	squashfs_cache_delete(sbi->fragment_cache);
	395	squashfs_cache_delete(sbi->read_page);
	396	squashfs_decompressor_destroy(sbi);
	397	kfree(sbi->id_table);
	398	kfree(sbi->fragment_index);
	399	kfree(sbi->meta_index);
	400	kfree(sbi->inode_lookup_table);
	401	kfree(sbi->xattr_id_table);
	402	kfree(sb->s_fs_info);
	403	sb->s_fs_info = NULL;
	404	}
	405	}
	406
	407	static struct kmem_cache *squashfs_inode_cachep;
	408
	409
	410	static void init_once(void *foo)
	411	{
	412	struct squashfs_inode_info *ei = foo;
	413
	414	inode_init_once(&ei->vfs_inode);
	415	}
	416
	417
	418	static int __init init_inodecache(void)
	419	{
	420	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
	421	sizeof(struct squashfs_inode_info), 0,
	422	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT\|SLAB_ACCOUNT,
	423	init_once);
	424
	425	return squashfs_inode_cachep ? 0 : -ENOMEM;
	426	}
	427
	428
	429	static void destroy_inodecache(void)
	430	{
	431	/*
	432	* Make sure all delayed rcu free inodes are flushed before we
	433	* destroy cache.
	434	*/
	435	rcu_barrier();
	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
	453	pr_info("version 4.0 (2009/01/31) Phillip Lougher\n");
	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
	475	static void squashfs_free_inode(struct inode *inode)
	476	{
	477	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
	478	}
	479
	480	static struct file_system_type squashfs_fs_type = {
	481	.owner = THIS_MODULE,
	482	.name = "squashfs",
	483	.init_fs_context = squashfs_init_fs_context,
	484	.kill_sb = kill_block_super,
	485	.fs_flags = FS_REQUIRES_DEV
	486	};
	487	MODULE_ALIAS_FS("squashfs");
	488
	489	static const struct super_operations squashfs_super_ops = {
	490	.alloc_inode = squashfs_alloc_inode,
	491	.free_inode = squashfs_free_inode,
	492	.statfs = squashfs_statfs,
	493	.put_super = squashfs_put_super,
	494	};
	495
	496	module_init(init_squashfs_fs);
	497	module_exit(exit_squashfs_fs);
	498	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
	499	MODULE_AUTHOR("Phillip Lougher <phillip@squashfs.org.uk>");
	500	MODULE_LICENSE("GPL");