[net-next-2.6.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 <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 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 (2009/01/31) "
		"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 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>
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;
	46	static struct super_operations squashfs_super_ops;
	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
	89	msblk->stream.workspace = kmalloc(zlib_inflate_workspacesize(),
	90	GFP_KERNEL);
	91	if (msblk->stream.workspace == NULL) {
	92	ERROR("Failed to allocate zlib workspace\n");
	93	goto failure;
	94	}
	95
	96	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
	97	if (sblk == NULL) {
	98	ERROR("Failed to allocate squashfs_super_block\n");
	99	goto failure;
	100	}
	101
	102	msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
103	msblk->devblksize_log2 = ffz(~msblk->devblksize);
104
105	mutex_init(&msblk->read_data_mutex);
106	mutex_init(&msblk->meta_index_mutex);
107
108	/*
109	* msblk->bytes_used is checked in squashfs_read_table to ensure reads
110	* are not beyond filesystem end. But as we're using
111	* squashfs_read_table here to read the superblock (including the value
112	* of bytes_used) we need to set it to an initial sensible dummy value
113	*/
114	msblk->bytes_used = sizeof(*sblk);
115	err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));
116
117	if (err < 0) {
118	ERROR("unable to read squashfs_super_block\n");
119	goto failed_mount;
120	}
121
122	/* Check it is a SQUASHFS superblock */
123	sb->s_magic = le32_to_cpu(sblk->s_magic);
124	if (sb->s_magic != SQUASHFS_MAGIC) {
125	if (!silent)
126	ERROR("Can't find a SQUASHFS superblock on %s\n",
127	bdevname(sb->s_bdev, b));
128	err = -EINVAL;
129	goto failed_mount;
130	}
131
132	/* Check the MAJOR & MINOR versions and compression type */
133	err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
134	le16_to_cpu(sblk->s_minor),
135	le16_to_cpu(sblk->compression));
136	if (err < 0)
137	goto failed_mount;
138
139	err = -EINVAL;
140
141	/*
142	* Check if there's xattrs in the filesystem. These are not
143	* supported in this version, so warn that they will be ignored.
144	*/
145	if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
146	ERROR("Xattrs in filesystem, these will be ignored\n");
147
148	/* Check the filesystem does not extend beyond the end of the
149	block device */
150	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
151	if (msblk->bytes_used < 0 \|\| msblk->bytes_used >
152	i_size_read(sb->s_bdev->bd_inode))
153	goto failed_mount;
154
155	/* Check block size for sanity */
156	msblk->block_size = le32_to_cpu(sblk->block_size);
157	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
158	goto failed_mount;
159
160	msblk->block_log = le16_to_cpu(sblk->block_log);
161	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
162	goto failed_mount;
163
164	/* Check the root inode for sanity */
165	root_inode = le64_to_cpu(sblk->root_inode);
166	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
167	goto failed_mount;
168
169	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
170	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
171	msblk->inodes = le32_to_cpu(sblk->inodes);
172	flags = le16_to_cpu(sblk->flags);
173
174	TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
175	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
176	? "un" : "");
177	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
178	? "un" : "");
179	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
180	TRACE("Block size %d\n", msblk->block_size);
181	TRACE("Number of inodes %d\n", msblk->inodes);
182	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
183	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
184	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
185	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
186	TRACE("sblk->fragment_table_start %llx\n",
187	(u64) le64_to_cpu(sblk->fragment_table_start));
188	TRACE("sblk->id_table_start %llx\n",
189	(u64) le64_to_cpu(sblk->id_table_start));
190
191	sb->s_maxbytes = MAX_LFS_FILESIZE;
192	sb->s_flags \|= MS_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", 1, msblk->block_size);
204	if (msblk->read_page == NULL) {
205	ERROR("Failed to allocate read_page block\n");
206	goto failed_mount;
207	}
208
209	/* Allocate and read id index table */
210	msblk->id_table = squashfs_read_id_index_table(sb,
211	le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
212	if (IS_ERR(msblk->id_table)) {
213	err = PTR_ERR(msblk->id_table);
214	msblk->id_table = NULL;
215	goto failed_mount;
216	}
217
218	fragments = le32_to_cpu(sblk->fragments);
219	if (fragments == 0)
220	goto allocate_lookup_table;
221
222	msblk->fragment_cache = squashfs_cache_init("fragment",
223	SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
224	if (msblk->fragment_cache == NULL) {
225	err = -ENOMEM;
226	goto failed_mount;
227	}
228
229	/* Allocate and read fragment index table */
230	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
231	le64_to_cpu(sblk->fragment_table_start), fragments);
232	if (IS_ERR(msblk->fragment_index)) {
233	err = PTR_ERR(msblk->fragment_index);
234	msblk->fragment_index = NULL;
235	goto failed_mount;
236	}
237
238	allocate_lookup_table:
239	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
240	if (lookup_table_start == SQUASHFS_INVALID_BLK)
241	goto allocate_root;
242
243	/* Allocate and read inode lookup table */
244	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
245	lookup_table_start, msblk->inodes);
246	if (IS_ERR(msblk->inode_lookup_table)) {
247	err = PTR_ERR(msblk->inode_lookup_table);
248	msblk->inode_lookup_table = NULL;
249	goto failed_mount;
250	}
251
252	sb->s_export_op = &squashfs_export_ops;
253
254	allocate_root:
255	root = new_inode(sb);
256	if (!root) {
257	err = -ENOMEM;
258	goto failed_mount;
259	}
260
261	err = squashfs_read_inode(root, root_inode);
262	if (err) {
263	iget_failed(root);
264	goto failed_mount;
265	}
266	insert_inode_hash(root);
267
268	sb->s_root = d_alloc_root(root);
269	if (sb->s_root == NULL) {
270	ERROR("Root inode create failed\n");
271	err = -ENOMEM;
272	iput(root);
273	goto failed_mount;
274	}
275
276	TRACE("Leaving squashfs_fill_super\n");
277	kfree(sblk);
278	return 0;
279
280	failed_mount:
281	squashfs_cache_delete(msblk->block_cache);
282	squashfs_cache_delete(msblk->fragment_cache);
283	squashfs_cache_delete(msblk->read_page);
284	kfree(msblk->inode_lookup_table);
285	kfree(msblk->fragment_index);
286	kfree(msblk->id_table);
287	kfree(msblk->stream.workspace);
288	kfree(sb->s_fs_info);
289	sb->s_fs_info = NULL;
290	kfree(sblk);
291	return err;
292
293	failure:
294	kfree(msblk->stream.workspace);
295	kfree(sb->s_fs_info);
296	sb->s_fs_info = NULL;
297	return -ENOMEM;
298	}
299
300
301	static int squashfs_statfs(struct dentry dentry, struct kstatfs buf)
302	{
303	struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
304
305	TRACE("Entered squashfs_statfs\n");
306
307	buf->f_type = SQUASHFS_MAGIC;
308	buf->f_bsize = msblk->block_size;
309	buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
310	buf->f_bfree = buf->f_bavail = 0;
311	buf->f_files = msblk->inodes;
312	buf->f_ffree = 0;
313	buf->f_namelen = SQUASHFS_NAME_LEN;
314
315	return 0;
316	}
317
318
319	static int squashfs_remount(struct super_block sb, int flags, char *data)
320	{
321	*flags \|= MS_RDONLY;
322	return 0;
323	}
324
325
326	static void squashfs_put_super(struct super_block *sb)
327	{
328	if (sb->s_fs_info) {
329	struct squashfs_sb_info *sbi = sb->s_fs_info;
330	squashfs_cache_delete(sbi->block_cache);
331	squashfs_cache_delete(sbi->fragment_cache);
332	squashfs_cache_delete(sbi->read_page);
333	kfree(sbi->id_table);
334	kfree(sbi->fragment_index);
335	kfree(sbi->meta_index);
336	kfree(sbi->stream.workspace);
337	kfree(sb->s_fs_info);
338	sb->s_fs_info = NULL;
339	}
340	}
341
342
343	static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
344	const char dev_name, void data,
345	struct vfsmount *mnt)
346	{
347	return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
348	mnt);
349	}
350
351
352	static struct kmem_cache *squashfs_inode_cachep;
353
354
355	static void init_once(void *foo)
356	{
357	struct squashfs_inode_info *ei = foo;
358
359	inode_init_once(&ei->vfs_inode);
360	}
361
362
363	static int __init init_inodecache(void)
364	{
365	squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
366	sizeof(struct squashfs_inode_info), 0,
367	SLAB_HWCACHE_ALIGN\|SLAB_RECLAIM_ACCOUNT, init_once);
368
369	return squashfs_inode_cachep ? 0 : -ENOMEM;
370	}
371
372
373	static void destroy_inodecache(void)
374	{
375	kmem_cache_destroy(squashfs_inode_cachep);
376	}
377
378
379	static int __init init_squashfs_fs(void)
380	{
381	int err = init_inodecache();
382
383	if (err)
384	return err;
385
386	err = register_filesystem(&squashfs_fs_type);
387	if (err) {
388	destroy_inodecache();
389	return err;
390	}
391
118e1ef6	392	printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
0aa66619 PL	393	"Phillip Lougher\n");
	394
	395	return 0;
	396	}
	397
	398
	399	static void __exit exit_squashfs_fs(void)
	400	{
	401	unregister_filesystem(&squashfs_fs_type);
	402	destroy_inodecache();
	403	}
	404
	405
	406	static struct inode squashfs_alloc_inode(struct super_block sb)
	407	{
	408	struct squashfs_inode_info *ei =
	409	kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
	410
	411	return ei ? &ei->vfs_inode : NULL;
	412	}
	413
	414
	415	static void squashfs_destroy_inode(struct inode *inode)
	416	{
	417	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
	418	}
	419
	420
	421	static struct file_system_type squashfs_fs_type = {
	422	.owner = THIS_MODULE,
	423	.name = "squashfs",
	424	.get_sb = squashfs_get_sb,
	425	.kill_sb = kill_block_super,
	426	.fs_flags = FS_REQUIRES_DEV
	427	};
	428
	429	static struct super_operations squashfs_super_ops = {
	430	.alloc_inode = squashfs_alloc_inode,
	431	.destroy_inode = squashfs_destroy_inode,
	432	.statfs = squashfs_statfs,
	433	.put_super = squashfs_put_super,
	434	.remount_fs = squashfs_remount
	435	};
	436
	437	module_init(init_squashfs_fs);
	438	module_exit(exit_squashfs_fs);
	439	MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
	440	MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
	441	MODULE_LICENSE("GPL");