mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
587 lines
15 KiB
587 lines
15 KiB
// 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 <[email protected]> |
|
* |
|
* 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/blkdev.h> |
|
#include <linux/fs.h> |
|
#include <linux/fs_context.h> |
|
#include <linux/fs_parser.h> |
|
#include <linux/vfs.h> |
|
#include <linux/slab.h> |
|
#include <linux/mutex.h> |
|
#include <linux/seq_file.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; |
|
|
|
enum Opt_errors { |
|
Opt_errors_continue, |
|
Opt_errors_panic, |
|
}; |
|
|
|
enum squashfs_param { |
|
Opt_errors, |
|
}; |
|
|
|
struct squashfs_mount_opts { |
|
enum Opt_errors errors; |
|
}; |
|
|
|
static const struct constant_table squashfs_param_errors[] = { |
|
{"continue", Opt_errors_continue }, |
|
{"panic", Opt_errors_panic }, |
|
{} |
|
}; |
|
|
|
static const struct fs_parameter_spec squashfs_fs_parameters[] = { |
|
fsparam_enum("errors", Opt_errors, squashfs_param_errors), |
|
{} |
|
}; |
|
|
|
static int squashfs_parse_param(struct fs_context *fc, struct fs_parameter *param) |
|
{ |
|
struct squashfs_mount_opts *opts = fc->fs_private; |
|
struct fs_parse_result result; |
|
int opt; |
|
|
|
opt = fs_parse(fc, squashfs_fs_parameters, param, &result); |
|
if (opt < 0) |
|
return opt; |
|
|
|
switch (opt) { |
|
case Opt_errors: |
|
opts->errors = result.uint_32; |
|
break; |
|
default: |
|
return -EINVAL; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
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_mount_opts *opts = fc->fs_private; |
|
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->panic_on_errors = (opts->errors == Opt_errors_panic); |
|
|
|
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 > bdev_nr_bytes(sb->s_bdev)) |
|
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) |
|
{ |
|
struct super_block *sb = fc->root->d_sb; |
|
struct squashfs_sb_info *msblk = sb->s_fs_info; |
|
struct squashfs_mount_opts *opts = fc->fs_private; |
|
|
|
sync_filesystem(fc->root->d_sb); |
|
fc->sb_flags |= SB_RDONLY; |
|
|
|
msblk->panic_on_errors = (opts->errors == Opt_errors_panic); |
|
|
|
return 0; |
|
} |
|
|
|
static void squashfs_free_fs_context(struct fs_context *fc) |
|
{ |
|
kfree(fc->fs_private); |
|
} |
|
|
|
static const struct fs_context_operations squashfs_context_ops = { |
|
.get_tree = squashfs_get_tree, |
|
.free = squashfs_free_fs_context, |
|
.parse_param = squashfs_parse_param, |
|
.reconfigure = squashfs_reconfigure, |
|
}; |
|
|
|
static int squashfs_show_options(struct seq_file *s, struct dentry *root) |
|
{ |
|
struct super_block *sb = root->d_sb; |
|
struct squashfs_sb_info *msblk = sb->s_fs_info; |
|
|
|
if (msblk->panic_on_errors) |
|
seq_puts(s, ",errors=panic"); |
|
else |
|
seq_puts(s, ",errors=continue"); |
|
|
|
return 0; |
|
} |
|
|
|
static int squashfs_init_fs_context(struct fs_context *fc) |
|
{ |
|
struct squashfs_mount_opts *opts; |
|
|
|
opts = kzalloc(sizeof(*opts), GFP_KERNEL); |
|
if (!opts) |
|
return -ENOMEM; |
|
|
|
fc->fs_private = opts; |
|
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 = |
|
alloc_inode_sb(sb, 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, |
|
.parameters = squashfs_fs_parameters, |
|
.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, |
|
.show_options = squashfs_show_options, |
|
}; |
|
|
|
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");
|
|
|