[deliverable/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 <phillip@lougher.demon.co.uk>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2,
 * or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * super.c
 */

/*
 * This file implements code to read the superblock, read and initialise
 * in-memory structures at mount time, and all the VFS glue code to register
 * the filesystem.
 */

#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/zlib.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 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.workspace = kmalloc(zlib_inflate_workspacesize(),
		GFP_KERNEL);
	if (msblk->stream.workspace == NULL) {
		ERROR("Failed to allocate zlib workspace\n");
		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;

	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);
	kfree(msblk->inode_lookup_table);
	kfree(msblk->fragment_index);
	kfree(msblk->id_table);
	kfree(msblk->stream.workspace);
	kfree(sb->s_fs_info);
	sb->s_fs_info = NULL;
	kfree(sblk);
	return err;

failure:
	kfree(msblk->stream.workspace);
	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;

	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;

	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);
		kfree(sbi->id_table);
		kfree(sbi->fragment_index);
		kfree(sbi->meta_index);
		kfree(sbi->stream.workspace);
		kfree(sb->s_fs_info);
		sb->s_fs_info = NULL;
	}
}


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 (2009/01/03) "
		"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 struct super_operations squashfs_super_ops = {
	.alloc_inode = squashfs_alloc_inode,
	.destroy_inode = squashfs_destroy_inode,
	.statfs = squashfs_statfs,
	.put_super = squashfs_put_super,
	.remount_fs = squashfs_remount
};

module_init(init_squashfs_fs);
module_exit(exit_squashfs_fs);
MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
MODULE_LICENSE("GPL");
Commit	Line	Data
0aa66619 PL	1	/*
	2	* Squashfs - a compressed read only filesystem for Linux
	3	*
	4	* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
	5	* Phillip Lougher <phillip@lougher.demon.co.uk>
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version 2,
	10	* or (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	20	*
	21	* super.c
	22	*/
	23
	24	/*
	25	* This file implements code to read the superblock, read and initialise
	26	* in-memory structures at mount time, and all the VFS glue code to register
	27	* the filesystem.
	28	*/
	29
	30	#include <linux/fs.h>
	31	#include <linux/vfs.h>
	32	#include <linux/slab.h>
	33	#include <linux/mutex.h>
	34	#include <linux/pagemap.h>
	35	#include <linux/init.h>
	36	#include <linux/module.h>
	37	#include <linux/zlib.h>
	38
	39	#include "squashfs_fs.h"
	40	#include "squashfs_fs_sb.h"
	41	#include "squashfs_fs_i.h"
	42	#include "squashfs.h"
	43
	44	static struct file_system_type squashfs_fs_type;
	45	static struct super_operations squashfs_super_ops;
	46
	47	static int supported_squashfs_filesystem(short major, short minor, short comp)
	48	{
	49	if (major < SQUASHFS_MAJOR) {
	50	ERROR("Major/Minor mismatch, older Squashfs %d.%d "
	51	"filesystems are unsupported\n", major, minor);
	52	return -EINVAL;
	53	} else if (major > SQUASHFS_MAJOR \|\| minor > SQUASHFS_MINOR) {
	54	ERROR("Major/Minor mismatch, trying to mount newer "
	55	"%d.%d filesystem\n", major, minor);
	56	ERROR("Please update your kernel\n");
	57	return -EINVAL;
	58	}
	59
	60	if (comp != ZLIB_COMPRESSION)
	61	return -EINVAL;
	62
	63	return 0;
	64	}
65
66
67	static int squashfs_fill_super(struct super_block sb, void data, int silent)
68	{
69	struct squashfs_sb_info *msblk;
70	struct squashfs_super_block *sblk = NULL;
71	char b[BDEVNAME_SIZE];
72	struct inode *root;
73	long long root_inode;
74	unsigned short flags;
75	unsigned int fragments;
76	u64 lookup_table_start;
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->stream.workspace = kmalloc(zlib_inflate_workspacesize(),
89	GFP_KERNEL);
90	if (msblk->stream.workspace == NULL) {
91	ERROR("Failed to allocate zlib workspace\n");
92	goto failure;
93	}
94
95	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
96	if (sblk == NULL) {
97	ERROR("Failed to allocate squashfs_super_block\n");
98	goto failure;
99	}
100
101	msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
102	msblk->devblksize_log2 = ffz(~msblk->devblksize);
103
104	mutex_init(&msblk->read_data_mutex);
105	mutex_init(&msblk->meta_index_mutex);
106
107	/*
108	* msblk->bytes_used is checked in squashfs_read_table to ensure reads
109	* are not beyond filesystem end. But as we're using
110	* squashfs_read_table here to read the superblock (including the value
111	* of bytes_used) we need to set it to an initial sensible dummy value
112	*/
113	msblk->bytes_used = sizeof(*sblk);
114	err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));
115
116	if (err < 0) {
117	ERROR("unable to read squashfs_super_block\n");
118	goto failed_mount;
119	}
120
121	/* Check it is a SQUASHFS superblock */
122	sb->s_magic = le32_to_cpu(sblk->s_magic);
123	if (sb->s_magic != SQUASHFS_MAGIC) {
124	if (!silent)
125	ERROR("Can't find a SQUASHFS superblock on %s\n",
126	bdevname(sb->s_bdev, b));
127	err = -EINVAL;
128	goto failed_mount;
129	}
130
131	/* Check the MAJOR & MINOR versions and compression type */
132	err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
133	le16_to_cpu(sblk->s_minor),
134	le16_to_cpu(sblk->compression));
135	if (err < 0)
136	goto failed_mount;
137
138	err = -EINVAL;
139
140	/*
141	* Check if there's xattrs in the filesystem. These are not
142	* supported in this version, so warn that they will be ignored.
143	*/
144	if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
145	ERROR("Xattrs in filesystem, these will be ignored\n");
146
147	/* Check the filesystem does not extend beyond the end of the
148	block device */
149	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
150	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
151	i_size_read(sb->s_bdev->bd_inode))
152	goto failed_mount;
153
154	/* Check block size for sanity */
155	msblk->block_size = le32_to_cpu(sblk->block_size);
156	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
157	goto failed_mount;
158
159	msblk->block_log = le16_to_cpu(sblk->block_log);
160	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
161	goto failed_mount;
162
163	/* Check the root inode for sanity */
164	root_inode = le64_to_cpu(sblk->root_inode);
165	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
166	goto failed_mount;
167
168	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
169	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
170	msblk->inodes = le32_to_cpu(sblk->inodes);
171	flags = le16_to_cpu(sblk->flags);
172
173	TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
174	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
175	? "un" : "");
176	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
177	? "un" : "");
178	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
179	TRACE("Block size %d\n", msblk->block_size);
180	TRACE("Number of inodes %d\n", msblk->inodes);
181	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
182	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
183	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
184	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
185	TRACE("sblk->fragment_table_start %llx\n",
186	(u64) le64_to_cpu(sblk->fragment_table_start));
187	TRACE("sblk->id_table_start %llx\n",
188	(u64) le64_to_cpu(sblk->id_table_start));
189
190	sb->s_maxbytes = MAX_LFS_FILESIZE;
191	sb->s_flags \|= MS_RDONLY;
192	sb->s_op = &squashfs_super_ops;
193
194	err = -ENOMEM;
195
196	msblk->block_cache = squashfs_cache_init("metadata",
197	SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
198	if (msblk->block_cache == NULL)
199	goto failed_mount;
200
201	/* Allocate read_page block */
202	msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
203	if (msblk->read_page == NULL) {
204	ERROR("Failed to allocate read_page block\n");
205	goto failed_mount;
206	}
207
208	/* Allocate and read id index table */
209	msblk->id_table = squashfs_read_id_index_table(sb,
210	le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
211	if (IS_ERR(msblk->id_table)) {
212	err = PTR_ERR(msblk->id_table);
213	msblk->id_table = NULL;
214	goto failed_mount;
215	}
216
217	fragments = le32_to_cpu(sblk->fragments);
218	if (fragments == 0)
219	goto allocate_lookup_table;
220
221	msblk->fragment_cache = squashfs_cache_init("fragment",
222	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
223	if (msblk->fragment_cache == NULL) {
224	err = -ENOMEM;
225	goto failed_mount;
226	}
227
228	/* Allocate and read fragment index table */
229	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
230	le64_to_cpu(sblk->fragment_table_start), fragments);
231	if (IS_ERR(msblk->fragment_index)) {
232	err = PTR_ERR(msblk->fragment_index);
233	msblk->fragment_index = NULL;
234	goto failed_mount;
235	}
236
237	allocate_lookup_table:
238	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
239	if (lookup_table_start == SQUASHFS_INVALID_BLK)
240	goto allocate_root;
241
242	/* Allocate and read inode lookup table */
243	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
244	lookup_table_start, msblk->inodes);
245	if (IS_ERR(msblk->inode_lookup_table)) {
246	err = PTR_ERR(msblk->inode_lookup_table);
247	msblk->inode_lookup_table = NULL;
248	goto failed_mount;
249	}
250
251	sb->s_export_op = &squashfs_export_ops;
252
253	allocate_root:
254	root = new_inode(sb);
255	if (!root) {
256	err = -ENOMEM;
257	goto failed_mount;
258	}
259
260	err = squashfs_read_inode(root, root_inode);
261	if (err) {
262	iget_failed(root);
263	goto failed_mount;
264	}
265	insert_inode_hash(root);
266
267	sb->s_root = d_alloc_root(root);
268	if (sb->s_root == NULL) {
269	ERROR("Root inode create failed\n");
270	err = -ENOMEM;
271	iput(root);
272	goto failed_mount;
273	}
274
275	TRACE("Leaving squashfs_fill_super\n");
276	kfree(sblk);
277	return 0;
278
279	failed_mount:
280	squashfs_cache_delete(msblk->block_cache);
281	squashfs_cache_delete(msblk->fragment_cache);
282	squashfs_cache_delete(msblk->read_page);
283	kfree(msblk->inode_lookup_table);
284	kfree(msblk->fragment_index);
285	kfree(msblk->id_table);
286	kfree(msblk->stream.workspace);
287	kfree(sb->s_fs_info);
288	sb->s_fs_info = NULL;
289	kfree(sblk);
290	return err;
291
292	failure:
293	kfree(msblk->stream.workspace);
294	kfree(sb->s_fs_info);
295	sb->s_fs_info = NULL;
296	return -ENOMEM;
297	}
298
299
300	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
301	{
302	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
303
304	TRACE("Entered squashfs_statfs\n");
305
306	buf->f_type = SQUASHFS_MAGIC;
307	buf->f_bsize = msblk->block_size;
308	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
309	buf->f_bfree = buf->f_bavail = 0;
310	buf->f_files = msblk->inodes;
311	buf->f_ffree = 0;
312	buf->f_namelen = SQUASHFS_NAME_LEN;
313
314	return 0;
315	}
316
317
318	static int squashfs_remount(struct super_block sb, int flags, char *data)
319	{
320	*flags \|= MS_RDONLY;
321	return 0;
322	}
323
324
325	static void squashfs_put_super(struct super_block *sb)
326	{
327	if (sb->s_fs_info) {
328	struct squashfs_sb_info *sbi = sb->s_fs_info;
329	squashfs_cache_delete(sbi->block_cache);
330	squashfs_cache_delete(sbi->fragment_cache);
331	squashfs_cache_delete(sbi->read_page);
332	kfree(sbi->id_table);
333	kfree(sbi->fragment_index);
334	kfree(sbi->meta_index);
335	kfree(sbi->stream.workspace);
336	kfree(sb->s_fs_info);
337	sb->s_fs_info = NULL;
338	}
339	}
340
341
342	static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
343	const char dev_name, void data,
344	struct vfsmount *mnt)
345	{
346	return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
347	mnt);
348	}
349
350
351	static struct kmem_cache *squashfs_inode_cachep;
352
353
354	static void init_once(void *foo)
355	{
356	struct squashfs_inode_info *ei = foo;
357
358	inode_init_once(&ei->vfs_inode);
359	}
360
361
362	static int __init init_inodecache(void)
363	{
364	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
365	sizeof(struct squashfs_inode_info), 0,
366	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT, init_once);
367
368	return squashfs_inode_cachep ? 0 : -ENOMEM;
369	}
370
371
372	static void destroy_inodecache(void)
373	{
374	kmem_cache_destroy(squashfs_inode_cachep);
375	}
376
377
378	static int __init init_squashfs_fs(void)
379	{
380	int err = init_inodecache();
381
382	if (err)
383	return err;
384
385	err = register_filesystem(&squashfs_fs_type);
386	if (err) {
387	destroy_inodecache();
388	return err;
389	}
390
391	printk(KERN_INFO "squashfs: version 4.0 (2009/01/03) "
392	"Phillip Lougher\n");
393
394	return 0;
395	}
396
397
398	static void __exit exit_squashfs_fs(void)
399	{
400	unregister_filesystem(&squashfs_fs_type);
401	destroy_inodecache();
402	}
403
404
405	static struct inode squashfs_alloc_inode(struct super_block sb)
406	{
407	struct squashfs_inode_info *ei =
408	kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
409
410	return ei ? &ei->vfs_inode : NULL;
411	}
412
413
414	static void squashfs_destroy_inode(struct inode *inode)
415	{
416	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
417	}
418
419
420	static struct file_system_type squashfs_fs_type = {
421	.owner = THIS_MODULE,
422	.name = "squashfs",
423	.get_sb = squashfs_get_sb,
424	.kill_sb = kill_block_super,
425	.fs_flags = FS_REQUIRES_DEV
426	};
427
428	static struct super_operations squashfs_super_ops = {
429	.alloc_inode = squashfs_alloc_inode,
430	.destroy_inode = squashfs_destroy_inode,
431	.statfs = squashfs_statfs,
432	.put_super = squashfs_put_super,
433	.remount_fs = squashfs_remount
434	};
435
436	module_init(init_squashfs_fs);
437	module_exit(exit_squashfs_fs);
438	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
439	MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
440	MODULE_LICENSE("GPL");