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Ventoy/SQUASHFS/squashfs-tools-4.4/kernel/kernel-2.4/fs/squashfs/inode.c
longpanda 05a1b863a6 initial commit
2020-04-05 00:08:01 +08:00

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/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006
* 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* inode.c
*/
#include <linux/types.h>
#include <linux/squashfs_fs.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/zlib.h>
#include <linux/fs.h>
#include <linux/smp_lock.h>
#include <linux/locks.h>
#include <linux/init.h>
#include <linux/dcache.h>
#include <linux/wait.h>
#include <linux/blkdev.h>
#include <linux/vmalloc.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
#include "squashfs.h"
static struct super_block *squashfs_read_super(struct super_block *, void *, int);
static void squashfs_put_super(struct super_block *);
static int squashfs_statfs(struct super_block *, struct statfs *);
static int squashfs_symlink_readpage(struct file *file, struct page *page);
static int squashfs_readpage(struct file *file, struct page *page);
static int squashfs_readpage4K(struct file *file, struct page *page);
static int squashfs_readdir(struct file *, void *, filldir_t);
static struct dentry *squashfs_lookup(struct inode *, struct dentry *);
static struct inode *squashfs_iget(struct super_block *s, squashfs_inode_t inode);
static long long read_blocklist(struct inode *inode, int index,
int readahead_blks, char *block_list,
unsigned short **block_p, unsigned int *bsize);
static DECLARE_FSTYPE_DEV(squashfs_fs_type, "squashfs", squashfs_read_super);
static unsigned char squashfs_filetype_table[] = {
DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_FIFO, DT_SOCK
};
static struct super_operations squashfs_ops = {
.statfs = squashfs_statfs,
.put_super = squashfs_put_super,
};
SQSH_EXTERN struct address_space_operations squashfs_symlink_aops = {
.readpage = squashfs_symlink_readpage
};
SQSH_EXTERN struct address_space_operations squashfs_aops = {
.readpage = squashfs_readpage
};
SQSH_EXTERN struct address_space_operations squashfs_aops_4K = {
.readpage = squashfs_readpage4K
};
static struct file_operations squashfs_dir_ops = {
.read = generic_read_dir,
.readdir = squashfs_readdir
};
static struct inode_operations squashfs_dir_inode_ops = {
.lookup = squashfs_lookup
};
static struct buffer_head *get_block_length(struct super_block *s,
int *cur_index, int *offset, int *c_byte)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
unsigned short temp;
struct buffer_head *bh;
if (!(bh = sb_bread(s, *cur_index)))
goto out;
if (msblk->devblksize - *offset == 1) {
if (msblk->swap)
((unsigned char *) &temp)[1] = *((unsigned char *)
(bh->b_data + *offset));
else
((unsigned char *) &temp)[0] = *((unsigned char *)
(bh->b_data + *offset));
brelse(bh);
if (!(bh = sb_bread(s, ++(*cur_index))))
goto out;
if (msblk->swap)
((unsigned char *) &temp)[0] = *((unsigned char *)
bh->b_data);
else
((unsigned char *) &temp)[1] = *((unsigned char *)
bh->b_data);
*c_byte = temp;
*offset = 1;
} else {
if (msblk->swap) {
((unsigned char *) &temp)[1] = *((unsigned char *)
(bh->b_data + *offset));
((unsigned char *) &temp)[0] = *((unsigned char *)
(bh->b_data + *offset + 1));
} else {
((unsigned char *) &temp)[0] = *((unsigned char *)
(bh->b_data + *offset));
((unsigned char *) &temp)[1] = *((unsigned char *)
(bh->b_data + *offset + 1));
}
*c_byte = temp;
*offset += 2;
}
if (SQUASHFS_CHECK_DATA(msblk->sblk.flags)) {
if (*offset == msblk->devblksize) {
brelse(bh);
if (!(bh = sb_bread(s, ++(*cur_index))))
goto out;
*offset = 0;
}
if (*((unsigned char *) (bh->b_data + *offset)) !=
SQUASHFS_MARKER_BYTE) {
ERROR("Metadata block marker corrupt @ %x\n",
*cur_index);
brelse(bh);
goto out;
}
(*offset)++;
}
return bh;
out:
return NULL;
}
SQSH_EXTERN unsigned int squashfs_read_data(struct super_block *s, char *buffer,
long long index, unsigned int length,
long long *next_index)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct buffer_head *bh[((SQUASHFS_FILE_MAX_SIZE - 1) >>
msblk->devblksize_log2) + 2];
unsigned int offset = index & ((1 << msblk->devblksize_log2) - 1);
unsigned int cur_index = index >> msblk->devblksize_log2;
int bytes, avail_bytes, b = 0, k;
char *c_buffer;
unsigned int compressed;
unsigned int c_byte = length;
if (c_byte) {
bytes = msblk->devblksize - offset;
compressed = SQUASHFS_COMPRESSED_BLOCK(c_byte);
c_buffer = compressed ? msblk->read_data : buffer;
c_byte = SQUASHFS_COMPRESSED_SIZE_BLOCK(c_byte);
TRACE("Block @ 0x%llx, %scompressed size %d\n", index, compressed
? "" : "un", (unsigned int) c_byte);
if (!(bh[0] = sb_getblk(s, cur_index)))
goto block_release;
for (b = 1; bytes < c_byte; b++) {
if (!(bh[b] = sb_getblk(s, ++cur_index)))
goto block_release;
bytes += msblk->devblksize;
}
ll_rw_block(READ, b, bh);
} else {
if (!(bh[0] = get_block_length(s, &cur_index, &offset,
&c_byte)))
goto read_failure;
bytes = msblk->devblksize - offset;
compressed = SQUASHFS_COMPRESSED(c_byte);
c_buffer = compressed ? msblk->read_data : buffer;
c_byte = SQUASHFS_COMPRESSED_SIZE(c_byte);
TRACE("Block @ 0x%llx, %scompressed size %d\n", index, compressed
? "" : "un", (unsigned int) c_byte);
for (b = 1; bytes < c_byte; b++) {
if (!(bh[b] = sb_getblk(s, ++cur_index)))
goto block_release;
bytes += msblk->devblksize;
}
ll_rw_block(READ, b - 1, bh + 1);
}
if (compressed)
down(&msblk->read_data_mutex);
for (bytes = 0, k = 0; k < b; k++) {
avail_bytes = (c_byte - bytes) > (msblk->devblksize - offset) ?
msblk->devblksize - offset :
c_byte - bytes;
wait_on_buffer(bh[k]);
if (!buffer_uptodate(bh[k]))
goto block_release;
memcpy(c_buffer + bytes, bh[k]->b_data + offset, avail_bytes);
bytes += avail_bytes;
offset = 0;
brelse(bh[k]);
}
/*
* uncompress block
*/
if (compressed) {
int zlib_err;
msblk->stream.next_in = c_buffer;
msblk->stream.avail_in = c_byte;
msblk->stream.next_out = buffer;
msblk->stream.avail_out = msblk->read_size;
if (((zlib_err = zlib_inflateInit(&msblk->stream)) != Z_OK) ||
((zlib_err = zlib_inflate(&msblk->stream, Z_FINISH))
!= Z_STREAM_END) || ((zlib_err =
zlib_inflateEnd(&msblk->stream)) != Z_OK)) {
ERROR("zlib_fs returned unexpected result 0x%x\n",
zlib_err);
bytes = 0;
} else
bytes = msblk->stream.total_out;
up(&msblk->read_data_mutex);
}
if (next_index)
*next_index = index + c_byte + (length ? 0 :
(SQUASHFS_CHECK_DATA(msblk->sblk.flags)
? 3 : 2));
return bytes;
block_release:
while (--b >= 0)
brelse(bh[b]);
read_failure:
ERROR("sb_bread failed reading block 0x%x\n", cur_index);
return 0;
}
SQSH_EXTERN int squashfs_get_cached_block(struct super_block *s, char *buffer,
long long block, unsigned int offset,
int length, long long *next_block,
unsigned int *next_offset)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
int n, i, bytes, return_length = length;
long long next_index;
TRACE("Entered squashfs_get_cached_block [%llx:%x]\n", block, offset);
while ( 1 ) {
for (i = 0; i < SQUASHFS_CACHED_BLKS; i++)
if (msblk->block_cache[i].block == block)
break;
down(&msblk->block_cache_mutex);
if (i == SQUASHFS_CACHED_BLKS) {
/* read inode header block */
for (i = msblk->next_cache, n = SQUASHFS_CACHED_BLKS;
n ; n --, i = (i + 1) %
SQUASHFS_CACHED_BLKS)
if (msblk->block_cache[i].block !=
SQUASHFS_USED_BLK)
break;
if (n == 0) {
wait_queue_t wait;
init_waitqueue_entry(&wait, current);
add_wait_queue(&msblk->waitq, &wait);
set_current_state(TASK_UNINTERRUPTIBLE);
up(&msblk->block_cache_mutex);
schedule();
set_current_state(TASK_RUNNING);
remove_wait_queue(&msblk->waitq, &wait);
continue;
}
msblk->next_cache = (i + 1) % SQUASHFS_CACHED_BLKS;
if (msblk->block_cache[i].block ==
SQUASHFS_INVALID_BLK) {
if (!(msblk->block_cache[i].data =
kmalloc(SQUASHFS_METADATA_SIZE,
GFP_KERNEL))) {
ERROR("Failed to allocate cache"
"block\n");
up(&msblk->block_cache_mutex);
goto out;
}
}
msblk->block_cache[i].block = SQUASHFS_USED_BLK;
up(&msblk->block_cache_mutex);
if (!(msblk->block_cache[i].length =
squashfs_read_data(s,
msblk->block_cache[i].data,
block, 0, &next_index))) {
ERROR("Unable to read cache block [%llx:%x]\n",
block, offset);
goto out;
}
down(&msblk->block_cache_mutex);
wake_up(&msblk->waitq);
msblk->block_cache[i].block = block;
msblk->block_cache[i].next_index = next_index;
TRACE("Read cache block [%llx:%x]\n", block, offset);
}
if (msblk->block_cache[i].block != block) {
up(&msblk->block_cache_mutex);
continue;
}
if ((bytes = msblk->block_cache[i].length - offset) >= length) {
if (buffer)
memcpy(buffer, msblk->block_cache[i].data +
offset, length);
if (msblk->block_cache[i].length - offset == length) {
*next_block = msblk->block_cache[i].next_index;
*next_offset = 0;
} else {
*next_block = block;
*next_offset = offset + length;
}
up(&msblk->block_cache_mutex);
goto finish;
} else {
if (buffer) {
memcpy(buffer, msblk->block_cache[i].data +
offset, bytes);
buffer += bytes;
}
block = msblk->block_cache[i].next_index;
up(&msblk->block_cache_mutex);
length -= bytes;
offset = 0;
}
}
finish:
return return_length;
out:
return 0;
}
static int get_fragment_location(struct super_block *s, unsigned int fragment,
long long *fragment_start_block,
unsigned int *fragment_size)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
long long start_block =
msblk->fragment_index[SQUASHFS_FRAGMENT_INDEX(fragment)];
int offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
struct squashfs_fragment_entry fragment_entry;
if (msblk->swap) {
struct squashfs_fragment_entry sfragment_entry;
if (!squashfs_get_cached_block(s, (char *) &sfragment_entry,
start_block, offset,
sizeof(sfragment_entry), &start_block,
&offset))
goto out;
SQUASHFS_SWAP_FRAGMENT_ENTRY(&fragment_entry, &sfragment_entry);
} else
if (!squashfs_get_cached_block(s, (char *) &fragment_entry,
start_block, offset,
sizeof(fragment_entry), &start_block,
&offset))
goto out;
*fragment_start_block = fragment_entry.start_block;
*fragment_size = fragment_entry.size;
return 1;
out:
return 0;
}
SQSH_EXTERN void release_cached_fragment(struct squashfs_sb_info *msblk, struct
squashfs_fragment_cache *fragment)
{
down(&msblk->fragment_mutex);
fragment->locked --;
wake_up(&msblk->fragment_wait_queue);
up(&msblk->fragment_mutex);
}
SQSH_EXTERN struct squashfs_fragment_cache *get_cached_fragment(struct super_block
*s, long long start_block,
int length)
{
int i, n;
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
while ( 1 ) {
down(&msblk->fragment_mutex);
for (i = 0; i < SQUASHFS_CACHED_FRAGMENTS &&
msblk->fragment[i].block != start_block; i++);
if (i == SQUASHFS_CACHED_FRAGMENTS) {
for (i = msblk->next_fragment, n =
SQUASHFS_CACHED_FRAGMENTS; n &&
msblk->fragment[i].locked; n--, i = (i + 1) %
SQUASHFS_CACHED_FRAGMENTS);
if (n == 0) {
wait_queue_t wait;
init_waitqueue_entry(&wait, current);
add_wait_queue(&msblk->fragment_wait_queue,
&wait);
set_current_state(TASK_UNINTERRUPTIBLE);
up(&msblk->fragment_mutex);
schedule();
set_current_state(TASK_RUNNING);
remove_wait_queue(&msblk->fragment_wait_queue,
&wait);
continue;
}
msblk->next_fragment = (msblk->next_fragment + 1) %
SQUASHFS_CACHED_FRAGMENTS;
if (msblk->fragment[i].data == NULL)
if (!(msblk->fragment[i].data = SQUASHFS_ALLOC
(SQUASHFS_FILE_MAX_SIZE))) {
ERROR("Failed to allocate fragment "
"cache block\n");
up(&msblk->fragment_mutex);
goto out;
}
msblk->fragment[i].block = SQUASHFS_INVALID_BLK;
msblk->fragment[i].locked = 1;
up(&msblk->fragment_mutex);
if (!(msblk->fragment[i].length = squashfs_read_data(s,
msblk->fragment[i].data,
start_block, length, NULL))) {
ERROR("Unable to read fragment cache block "
"[%llx]\n", start_block);
msblk->fragment[i].locked = 0;
goto out;
}
msblk->fragment[i].block = start_block;
TRACE("New fragment %d, start block %lld, locked %d\n",
i, msblk->fragment[i].block,
msblk->fragment[i].locked);
break;
}
msblk->fragment[i].locked++;
up(&msblk->fragment_mutex);
TRACE("Got fragment %d, start block %lld, locked %d\n", i,
msblk->fragment[i].block,
msblk->fragment[i].locked);
break;
}
return &msblk->fragment[i];
out:
return NULL;
}
static struct inode *squashfs_new_inode(struct super_block *s,
struct squashfs_base_inode_header *inodeb)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct inode *i = new_inode(s);
if (i) {
i->i_ino = inodeb->inode_number;
i->i_mtime = inodeb->mtime;
i->i_atime = inodeb->mtime;
i->i_ctime = inodeb->mtime;
i->i_uid = msblk->uid[inodeb->uid];
i->i_mode = inodeb->mode;
i->i_size = 0;
if (inodeb->guid == SQUASHFS_GUIDS)
i->i_gid = i->i_uid;
else
i->i_gid = msblk->guid[inodeb->guid];
}
return i;
}
static struct inode *squashfs_iget(struct super_block *s, squashfs_inode_t inode)
{
struct inode *i;
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
long long block = SQUASHFS_INODE_BLK(inode) +
sblk->inode_table_start;
unsigned int offset = SQUASHFS_INODE_OFFSET(inode);
long long next_block;
unsigned int next_offset;
union squashfs_inode_header id, sid;
struct squashfs_base_inode_header *inodeb = &id.base,
*sinodeb = &sid.base;
TRACE("Entered squashfs_iget\n");
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *) sinodeb, block,
offset, sizeof(*sinodeb), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_BASE_INODE_HEADER(inodeb, sinodeb,
sizeof(*sinodeb));
} else
if (!squashfs_get_cached_block(s, (char *) inodeb, block,
offset, sizeof(*inodeb), &next_block,
&next_offset))
goto failed_read;
switch(inodeb->inode_type) {
case SQUASHFS_FILE_TYPE: {
unsigned int frag_size;
long long frag_blk;
struct squashfs_reg_inode_header *inodep = &id.reg;
struct squashfs_reg_inode_header *sinodep = &sid.reg;
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *)
sinodep, block, offset,
sizeof(*sinodep), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_REG_INODE_HEADER(inodep, sinodep);
} else
if (!squashfs_get_cached_block(s, (char *)
inodep, block, offset,
sizeof(*inodep), &next_block,
&next_offset))
goto failed_read;
frag_blk = SQUASHFS_INVALID_BLK;
if (inodep->fragment != SQUASHFS_INVALID_FRAG &&
!get_fragment_location(s,
inodep->fragment, &frag_blk, &frag_size))
goto failed_read;
if((i = squashfs_new_inode(s, inodeb)) == NULL)
goto failed_read1;
i->i_nlink = 1;
i->i_size = inodep->file_size;
i->i_fop = &generic_ro_fops;
i->i_mode |= S_IFREG;
i->i_blocks = ((i->i_size - 1) >> 9) + 1;
i->i_blksize = PAGE_CACHE_SIZE;
SQUASHFS_I(i)->u.s1.fragment_start_block = frag_blk;
SQUASHFS_I(i)->u.s1.fragment_size = frag_size;
SQUASHFS_I(i)->u.s1.fragment_offset = inodep->offset;
SQUASHFS_I(i)->start_block = inodep->start_block;
SQUASHFS_I(i)->u.s1.block_list_start = next_block;
SQUASHFS_I(i)->offset = next_offset;
if (sblk->block_size > 4096)
i->i_data.a_ops = &squashfs_aops;
else
i->i_data.a_ops = &squashfs_aops_4K;
TRACE("File inode %x:%x, start_block %llx, "
"block_list_start %llx, offset %x\n",
SQUASHFS_INODE_BLK(inode), offset,
inodep->start_block, next_block,
next_offset);
break;
}
case SQUASHFS_LREG_TYPE: {
unsigned int frag_size;
long long frag_blk;
struct squashfs_lreg_inode_header *inodep = &id.lreg;
struct squashfs_lreg_inode_header *sinodep = &sid.lreg;
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *)
sinodep, block, offset,
sizeof(*sinodep), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_LREG_INODE_HEADER(inodep, sinodep);
} else
if (!squashfs_get_cached_block(s, (char *)
inodep, block, offset,
sizeof(*inodep), &next_block,
&next_offset))
goto failed_read;
frag_blk = SQUASHFS_INVALID_BLK;
if (inodep->fragment != SQUASHFS_INVALID_FRAG &&
!get_fragment_location(s,
inodep->fragment, &frag_blk, &frag_size))
goto failed_read;
if((i = squashfs_new_inode(s, inodeb)) == NULL)
goto failed_read1;
i->i_nlink = inodep->nlink;
i->i_size = inodep->file_size;
i->i_fop = &generic_ro_fops;
i->i_mode |= S_IFREG;
i->i_blocks = ((i->i_size - 1) >> 9) + 1;
i->i_blksize = PAGE_CACHE_SIZE;
SQUASHFS_I(i)->u.s1.fragment_start_block = frag_blk;
SQUASHFS_I(i)->u.s1.fragment_size = frag_size;
SQUASHFS_I(i)->u.s1.fragment_offset = inodep->offset;
SQUASHFS_I(i)->start_block = inodep->start_block;
SQUASHFS_I(i)->u.s1.block_list_start = next_block;
SQUASHFS_I(i)->offset = next_offset;
if (sblk->block_size > 4096)
i->i_data.a_ops = &squashfs_aops;
else
i->i_data.a_ops = &squashfs_aops_4K;
TRACE("File inode %x:%x, start_block %llx, "
"block_list_start %llx, offset %x\n",
SQUASHFS_INODE_BLK(inode), offset,
inodep->start_block, next_block,
next_offset);
break;
}
case SQUASHFS_DIR_TYPE: {
struct squashfs_dir_inode_header *inodep = &id.dir;
struct squashfs_dir_inode_header *sinodep = &sid.dir;
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *)
sinodep, block, offset,
sizeof(*sinodep), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_DIR_INODE_HEADER(inodep, sinodep);
} else
if (!squashfs_get_cached_block(s, (char *)
inodep, block, offset,
sizeof(*inodep), &next_block,
&next_offset))
goto failed_read;
if((i = squashfs_new_inode(s, inodeb)) == NULL)
goto failed_read1;
i->i_nlink = inodep->nlink;
i->i_size = inodep->file_size;
i->i_op = &squashfs_dir_inode_ops;
i->i_fop = &squashfs_dir_ops;
i->i_mode |= S_IFDIR;
SQUASHFS_I(i)->start_block = inodep->start_block;
SQUASHFS_I(i)->offset = inodep->offset;
SQUASHFS_I(i)->u.s2.directory_index_count = 0;
SQUASHFS_I(i)->u.s2.parent_inode = inodep->parent_inode;
TRACE("Directory inode %x:%x, start_block %x, offset "
"%x\n", SQUASHFS_INODE_BLK(inode),
offset, inodep->start_block,
inodep->offset);
break;
}
case SQUASHFS_LDIR_TYPE: {
struct squashfs_ldir_inode_header *inodep = &id.ldir;
struct squashfs_ldir_inode_header *sinodep = &sid.ldir;
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *)
sinodep, block, offset,
sizeof(*sinodep), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_LDIR_INODE_HEADER(inodep,
sinodep);
} else
if (!squashfs_get_cached_block(s, (char *)
inodep, block, offset,
sizeof(*inodep), &next_block,
&next_offset))
goto failed_read;
if((i = squashfs_new_inode(s, inodeb)) == NULL)
goto failed_read1;
i->i_nlink = inodep->nlink;
i->i_size = inodep->file_size;
i->i_op = &squashfs_dir_inode_ops;
i->i_fop = &squashfs_dir_ops;
i->i_mode |= S_IFDIR;
SQUASHFS_I(i)->start_block = inodep->start_block;
SQUASHFS_I(i)->offset = inodep->offset;
SQUASHFS_I(i)->u.s2.directory_index_start = next_block;
SQUASHFS_I(i)->u.s2.directory_index_offset =
next_offset;
SQUASHFS_I(i)->u.s2.directory_index_count =
inodep->i_count;
SQUASHFS_I(i)->u.s2.parent_inode = inodep->parent_inode;
TRACE("Long directory inode %x:%x, start_block %x, "
"offset %x\n",
SQUASHFS_INODE_BLK(inode), offset,
inodep->start_block, inodep->offset);
break;
}
case SQUASHFS_SYMLINK_TYPE: {
struct squashfs_symlink_inode_header *inodep =
&id.symlink;
struct squashfs_symlink_inode_header *sinodep =
&sid.symlink;
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *)
sinodep, block, offset,
sizeof(*sinodep), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_SYMLINK_INODE_HEADER(inodep,
sinodep);
} else
if (!squashfs_get_cached_block(s, (char *)
inodep, block, offset,
sizeof(*inodep), &next_block,
&next_offset))
goto failed_read;
if((i = squashfs_new_inode(s, inodeb)) == NULL)
goto failed_read1;
i->i_nlink = inodep->nlink;
i->i_size = inodep->symlink_size;
i->i_op = &page_symlink_inode_operations;
i->i_data.a_ops = &squashfs_symlink_aops;
i->i_mode |= S_IFLNK;
SQUASHFS_I(i)->start_block = next_block;
SQUASHFS_I(i)->offset = next_offset;
TRACE("Symbolic link inode %x:%x, start_block %llx, "
"offset %x\n",
SQUASHFS_INODE_BLK(inode), offset,
next_block, next_offset);
break;
}
case SQUASHFS_BLKDEV_TYPE:
case SQUASHFS_CHRDEV_TYPE: {
struct squashfs_dev_inode_header *inodep = &id.dev;
struct squashfs_dev_inode_header *sinodep = &sid.dev;
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *)
sinodep, block, offset,
sizeof(*sinodep), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_DEV_INODE_HEADER(inodep, sinodep);
} else
if (!squashfs_get_cached_block(s, (char *)
inodep, block, offset,
sizeof(*inodep), &next_block,
&next_offset))
goto failed_read;
if ((i = squashfs_new_inode(s, inodeb)) == NULL)
goto failed_read1;
i->i_nlink = inodep->nlink;
i->i_mode |= (inodeb->inode_type ==
SQUASHFS_CHRDEV_TYPE) ? S_IFCHR :
S_IFBLK;
init_special_inode(i, i->i_mode, inodep->rdev);
TRACE("Device inode %x:%x, rdev %x\n",
SQUASHFS_INODE_BLK(inode), offset,
inodep->rdev);
break;
}
case SQUASHFS_FIFO_TYPE:
case SQUASHFS_SOCKET_TYPE: {
struct squashfs_ipc_inode_header *inodep = &id.ipc;
struct squashfs_ipc_inode_header *sinodep = &sid.ipc;
if (msblk->swap) {
if (!squashfs_get_cached_block(s, (char *)
sinodep, block, offset,
sizeof(*sinodep), &next_block,
&next_offset))
goto failed_read;
SQUASHFS_SWAP_IPC_INODE_HEADER(inodep, sinodep);
} else
if (!squashfs_get_cached_block(s, (char *)
inodep, block, offset,
sizeof(*inodep), &next_block,
&next_offset))
goto failed_read;
if ((i = squashfs_new_inode(s, inodeb)) == NULL)
goto failed_read1;
i->i_nlink = inodep->nlink;
i->i_mode |= (inodeb->inode_type == SQUASHFS_FIFO_TYPE)
? S_IFIFO : S_IFSOCK;
init_special_inode(i, i->i_mode, 0);
break;
}
default:
ERROR("Unknown inode type %d in squashfs_iget!\n",
inodeb->inode_type);
goto failed_read1;
}
insert_inode_hash(i);
return i;
failed_read:
ERROR("Unable to read inode [%llx:%x]\n", block, offset);
failed_read1:
return NULL;
}
int read_fragment_index_table(struct super_block *s)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
if (!(msblk->fragment_index = kmalloc(SQUASHFS_FRAGMENT_INDEX_BYTES
(sblk->fragments), GFP_KERNEL))) {
ERROR("Failed to allocate uid/gid table\n");
return 0;
}
if (SQUASHFS_FRAGMENT_INDEX_BYTES(sblk->fragments) &&
!squashfs_read_data(s, (char *)
msblk->fragment_index,
sblk->fragment_table_start,
SQUASHFS_FRAGMENT_INDEX_BYTES
(sblk->fragments) |
SQUASHFS_COMPRESSED_BIT_BLOCK, NULL)) {
ERROR("unable to read fragment index table\n");
return 0;
}
if (msblk->swap) {
int i;
long long fragment;
for (i = 0; i < SQUASHFS_FRAGMENT_INDEXES(sblk->fragments);
i++) {
SQUASHFS_SWAP_FRAGMENT_INDEXES((&fragment),
&msblk->fragment_index[i], 1);
msblk->fragment_index[i] = fragment;
}
}
return 1;
}
static int supported_squashfs_filesystem(struct squashfs_sb_info *msblk, int silent)
{
struct squashfs_super_block *sblk = &msblk->sblk;
msblk->iget = squashfs_iget;
msblk->read_blocklist = read_blocklist;
msblk->read_fragment_index_table = read_fragment_index_table;
if (sblk->s_major == 1) {
if (!squashfs_1_0_supported(msblk)) {
SERROR("Major/Minor mismatch, Squashfs 1.0 filesystems "
"are unsupported\n");
SERROR("Please recompile with "
"Squashfs 1.0 support enabled\n");
return 0;
}
} else if (sblk->s_major == 2) {
if (!squashfs_2_0_supported(msblk)) {
SERROR("Major/Minor mismatch, Squashfs 2.0 filesystems "
"are unsupported\n");
SERROR("Please recompile with "
"Squashfs 2.0 support enabled\n");
return 0;
}
} else if(sblk->s_major != SQUASHFS_MAJOR || sblk->s_minor >
SQUASHFS_MINOR) {
SERROR("Major/Minor mismatch, trying to mount newer %d.%d "
"filesystem\n", sblk->s_major, sblk->s_minor);
SERROR("Please update your kernel\n");
return 0;
}
return 1;
}
static struct super_block *squashfs_read_super(struct super_block *s,
void *data, int silent)
{
kdev_t dev = s->s_dev;
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
int i;
struct inode *root;
if (!(msblk->stream.workspace = vmalloc(zlib_inflate_workspacesize()))) {
ERROR("Failed to allocate zlib workspace\n");
goto failed_mount;
}
msblk->devblksize = get_hardsect_size(dev);
if(msblk->devblksize < BLOCK_SIZE)
msblk->devblksize = BLOCK_SIZE;
msblk->devblksize_log2 = ffz(~msblk->devblksize);
set_blocksize(dev, msblk->devblksize);
s->s_blocksize = msblk->devblksize;
s->s_blocksize_bits = msblk->devblksize_log2;
init_MUTEX(&msblk->read_data_mutex);
init_MUTEX(&msblk->read_page_mutex);
init_MUTEX(&msblk->block_cache_mutex);
init_MUTEX(&msblk->fragment_mutex);
init_waitqueue_head(&msblk->waitq);
init_waitqueue_head(&msblk->fragment_wait_queue);
if (!squashfs_read_data(s, (char *) sblk, SQUASHFS_START,
sizeof(struct squashfs_super_block) |
SQUASHFS_COMPRESSED_BIT_BLOCK, NULL)) {
SERROR("unable to read superblock\n");
goto failed_mount;
}
/* Check it is a SQUASHFS superblock */
msblk->swap = 0;
if ((s->s_magic = sblk->s_magic) != SQUASHFS_MAGIC) {
if (sblk->s_magic == SQUASHFS_MAGIC_SWAP) {
struct squashfs_super_block ssblk;
WARNING("Mounting a different endian SQUASHFS "
"filesystem on %s\n", bdevname(dev));
SQUASHFS_SWAP_SUPER_BLOCK(&ssblk, sblk);
memcpy(sblk, &ssblk, sizeof(struct squashfs_super_block));
msblk->swap = 1;
} else {
SERROR("Can't find a SQUASHFS superblock on %s\n",
bdevname(dev));
goto failed_mount;
}
}
/* Check the MAJOR & MINOR versions */
if(!supported_squashfs_filesystem(msblk, silent))
goto failed_mount;
TRACE("Found valid superblock on %s\n", bdevname(dev));
TRACE("Inodes are %scompressed\n",
SQUASHFS_UNCOMPRESSED_INODES
(sblk->flags) ? "un" : "");
TRACE("Data is %scompressed\n",
SQUASHFS_UNCOMPRESSED_DATA(sblk->flags)
? "un" : "");
TRACE("Check data is %s present in the filesystem\n",
SQUASHFS_CHECK_DATA(sblk->flags) ?
"" : "not");
TRACE("Filesystem size %lld bytes\n", sblk->bytes_used);
TRACE("Block size %d\n", sblk->block_size);
TRACE("Number of inodes %d\n", sblk->inodes);
if (sblk->s_major > 1)
TRACE("Number of fragments %d\n", sblk->fragments);
TRACE("Number of uids %d\n", sblk->no_uids);
TRACE("Number of gids %d\n", sblk->no_guids);
TRACE("sblk->inode_table_start %llx\n", sblk->inode_table_start);
TRACE("sblk->directory_table_start %llx\n", sblk->directory_table_start);
if (sblk->s_major > 1)
TRACE("sblk->fragment_table_start %llx\n",
sblk->fragment_table_start);
TRACE("sblk->uid_start %llx\n", sblk->uid_start);
s->s_flags |= MS_RDONLY;
s->s_op = &squashfs_ops;
/* Init inode_table block pointer array */
if (!(msblk->block_cache = kmalloc(sizeof(struct squashfs_cache) *
SQUASHFS_CACHED_BLKS, GFP_KERNEL))) {
ERROR("Failed to allocate block cache\n");
goto failed_mount;
}
for (i = 0; i < SQUASHFS_CACHED_BLKS; i++)
msblk->block_cache[i].block = SQUASHFS_INVALID_BLK;
msblk->next_cache = 0;
/* Allocate read_data block */
msblk->read_size = (sblk->block_size < SQUASHFS_METADATA_SIZE) ?
SQUASHFS_METADATA_SIZE :
sblk->block_size;
if (!(msblk->read_data = kmalloc(msblk->read_size, GFP_KERNEL))) {
ERROR("Failed to allocate read_data block\n");
goto failed_mount;
}
/* Allocate read_page block */
if (!(msblk->read_page = kmalloc(sblk->block_size, GFP_KERNEL))) {
ERROR("Failed to allocate read_page block\n");
goto failed_mount;
}
/* Allocate uid and gid tables */
if (!(msblk->uid = kmalloc((sblk->no_uids + sblk->no_guids) *
sizeof(unsigned int), GFP_KERNEL))) {
ERROR("Failed to allocate uid/gid table\n");
goto failed_mount;
}
msblk->guid = msblk->uid + sblk->no_uids;
if (msblk->swap) {
unsigned int suid[sblk->no_uids + sblk->no_guids];
if (!squashfs_read_data(s, (char *) &suid, sblk->uid_start,
((sblk->no_uids + sblk->no_guids) *
sizeof(unsigned int)) |
SQUASHFS_COMPRESSED_BIT_BLOCK, NULL)) {
ERROR("unable to read uid/gid table\n");
goto failed_mount;
}
SQUASHFS_SWAP_DATA(msblk->uid, suid, (sblk->no_uids +
sblk->no_guids), (sizeof(unsigned int) * 8));
} else
if (!squashfs_read_data(s, (char *) msblk->uid, sblk->uid_start,
((sblk->no_uids + sblk->no_guids) *
sizeof(unsigned int)) |
SQUASHFS_COMPRESSED_BIT_BLOCK, NULL)) {
ERROR("unable to read uid/gid table\n");
goto failed_mount;
}
if (sblk->s_major == 1 && squashfs_1_0_supported(msblk))
goto allocate_root;
if (!(msblk->fragment = kmalloc(sizeof(struct squashfs_fragment_cache) *
SQUASHFS_CACHED_FRAGMENTS, GFP_KERNEL))) {
ERROR("Failed to allocate fragment block cache\n");
goto failed_mount;
}
for (i = 0; i < SQUASHFS_CACHED_FRAGMENTS; i++) {
msblk->fragment[i].locked = 0;
msblk->fragment[i].block = SQUASHFS_INVALID_BLK;
msblk->fragment[i].data = NULL;
}
msblk->next_fragment = 0;
/* Allocate fragment index table */
if(msblk->read_fragment_index_table(s) == 0)
goto failed_mount;
allocate_root:
if ((root = (msblk->iget)(s, sblk->root_inode)) == NULL)
goto failed_mount;
if ((s->s_root = d_alloc_root(root)) == NULL) {
ERROR("Root inode create failed\n");
iput(root);
goto failed_mount;
}
TRACE("Leaving squashfs_read_super\n");
return s;
failed_mount:
kfree(msblk->fragment_index);
kfree(msblk->fragment);
kfree(msblk->uid);
kfree(msblk->read_page);
kfree(msblk->read_data);
kfree(msblk->block_cache);
kfree(msblk->fragment_index_2);
vfree(msblk->stream.workspace);
return NULL;
}
static int squashfs_statfs(struct super_block *s, struct statfs *buf)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
TRACE("Entered squashfs_statfs\n");
buf->f_type = SQUASHFS_MAGIC;
buf->f_bsize = sblk->block_size;
buf->f_blocks = ((sblk->bytes_used - 1) >> sblk->block_log) + 1;
buf->f_bfree = buf->f_bavail = 0;
buf->f_files = sblk->inodes;
buf->f_ffree = 0;
buf->f_namelen = SQUASHFS_NAME_LEN;
return 0;
}
static int squashfs_symlink_readpage(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
int index = page->index << PAGE_CACHE_SHIFT, length, bytes;
long long block = SQUASHFS_I(inode)->start_block;
int offset = SQUASHFS_I(inode)->offset;
void *pageaddr = kmap(page);
TRACE("Entered squashfs_symlink_readpage, page index %ld, start block "
"%llx, offset %x\n", page->index,
SQUASHFS_I(inode)->start_block,
SQUASHFS_I(inode)->offset);
for (length = 0; length < index; length += bytes) {
if (!(bytes = squashfs_get_cached_block(inode->i_sb, NULL,
block, offset, PAGE_CACHE_SIZE, &block,
&offset))) {
ERROR("Unable to read symbolic link [%llx:%x]\n", block,
offset);
goto skip_read;
}
}
if (length != index) {
ERROR("(squashfs_symlink_readpage) length != index\n");
bytes = 0;
goto skip_read;
}
bytes = (i_size_read(inode) - length) > PAGE_CACHE_SIZE ? PAGE_CACHE_SIZE :
i_size_read(inode) - length;
if (!(bytes = squashfs_get_cached_block(inode->i_sb, pageaddr, block,
offset, bytes, &block, &offset)))
ERROR("Unable to read symbolic link [%llx:%x]\n", block, offset);
skip_read:
memset(pageaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
kunmap(page);
SetPageUptodate(page);
UnlockPage(page);
return 0;
}
struct meta_index *locate_meta_index(struct inode *inode, int index, int offset)
{
struct meta_index *meta = NULL;
struct squashfs_sb_info *msblk = &inode->i_sb->u.squashfs_sb;
int i;
down(&msblk->meta_index_mutex);
TRACE("locate_meta_index: index %d, offset %d\n", index, offset);
if(msblk->meta_index == NULL)
goto not_allocated;
for (i = 0; i < SQUASHFS_META_NUMBER; i ++)
if (msblk->meta_index[i].inode_number == inode->i_ino &&
msblk->meta_index[i].offset >= offset &&
msblk->meta_index[i].offset <= index &&
msblk->meta_index[i].locked == 0) {
TRACE("locate_meta_index: entry %d, offset %d\n", i,
msblk->meta_index[i].offset);
meta = &msblk->meta_index[i];
offset = meta->offset;
}
if (meta)
meta->locked = 1;
not_allocated:
up(&msblk->meta_index_mutex);
return meta;
}
struct meta_index *empty_meta_index(struct inode *inode, int offset, int skip)
{
struct squashfs_sb_info *msblk = &inode->i_sb->u.squashfs_sb;
struct meta_index *meta = NULL;
int i;
down(&msblk->meta_index_mutex);
TRACE("empty_meta_index: offset %d, skip %d\n", offset, skip);
if(msblk->meta_index == NULL) {
if (!(msblk->meta_index = kmalloc(sizeof(struct meta_index) *
SQUASHFS_META_NUMBER, GFP_KERNEL))) {
ERROR("Failed to allocate meta_index\n");
goto failed;
}
for(i = 0; i < SQUASHFS_META_NUMBER; i++) {
msblk->meta_index[i].inode_number = 0;
msblk->meta_index[i].locked = 0;
}
msblk->next_meta_index = 0;
}
for(i = SQUASHFS_META_NUMBER; i &&
msblk->meta_index[msblk->next_meta_index].locked; i --)
msblk->next_meta_index = (msblk->next_meta_index + 1) %
SQUASHFS_META_NUMBER;
if(i == 0) {
TRACE("empty_meta_index: failed!\n");
goto failed;
}
TRACE("empty_meta_index: returned meta entry %d, %p\n",
msblk->next_meta_index,
&msblk->meta_index[msblk->next_meta_index]);
meta = &msblk->meta_index[msblk->next_meta_index];
msblk->next_meta_index = (msblk->next_meta_index + 1) %
SQUASHFS_META_NUMBER;
meta->inode_number = inode->i_ino;
meta->offset = offset;
meta->skip = skip;
meta->entries = 0;
meta->locked = 1;
failed:
up(&msblk->meta_index_mutex);
return meta;
}
void release_meta_index(struct inode *inode, struct meta_index *meta)
{
meta->locked = 0;
}
static int read_block_index(struct super_block *s, int blocks, char *block_list,
long long *start_block, int *offset)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
unsigned int *block_listp;
int block = 0;
if (msblk->swap) {
char sblock_list[blocks << 2];
if (!squashfs_get_cached_block(s, sblock_list, *start_block,
*offset, blocks << 2, start_block, offset)) {
ERROR("Unable to read block list [%llx:%x]\n",
*start_block, *offset);
goto failure;
}
SQUASHFS_SWAP_INTS(((unsigned int *)block_list),
((unsigned int *)sblock_list), blocks);
} else
if (!squashfs_get_cached_block(s, block_list, *start_block,
*offset, blocks << 2, start_block, offset)) {
ERROR("Unable to read block list [%llx:%x]\n",
*start_block, *offset);
goto failure;
}
for (block_listp = (unsigned int *) block_list; blocks;
block_listp++, blocks --)
block += SQUASHFS_COMPRESSED_SIZE_BLOCK(*block_listp);
return block;
failure:
return -1;
}
#define SIZE 256
static inline int calculate_skip(int blocks) {
int skip = (blocks - 1) / ((SQUASHFS_SLOTS * SQUASHFS_META_ENTRIES + 1) * SQUASHFS_META_INDEXES);
return skip >= 7 ? 7 : skip + 1;
}
static int get_meta_index(struct inode *inode, int index,
long long *index_block, int *index_offset,
long long *data_block, char *block_list)
{
struct squashfs_sb_info *msblk = &inode->i_sb->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
int skip = calculate_skip(i_size_read(inode) >> sblk->block_log);
int offset = 0;
struct meta_index *meta;
struct meta_entry *meta_entry;
long long cur_index_block = SQUASHFS_I(inode)->u.s1.block_list_start;
int cur_offset = SQUASHFS_I(inode)->offset;
long long cur_data_block = SQUASHFS_I(inode)->start_block;
int i;
index /= SQUASHFS_META_INDEXES * skip;
while ( offset < index ) {
meta = locate_meta_index(inode, index, offset + 1);
if (meta == NULL) {
if ((meta = empty_meta_index(inode, offset + 1,
skip)) == NULL)
goto all_done;
} else {
offset = index < meta->offset + meta->entries ? index :
meta->offset + meta->entries - 1;
meta_entry = &meta->meta_entry[offset - meta->offset];
cur_index_block = meta_entry->index_block + sblk->inode_table_start;
cur_offset = meta_entry->offset;
cur_data_block = meta_entry->data_block;
TRACE("get_meta_index: offset %d, meta->offset %d, "
"meta->entries %d\n", offset, meta->offset,
meta->entries);
TRACE("get_meta_index: index_block 0x%llx, offset 0x%x"
" data_block 0x%llx\n", cur_index_block,
cur_offset, cur_data_block);
}
for (i = meta->offset + meta->entries; i <= index &&
i < meta->offset + SQUASHFS_META_ENTRIES; i++) {
int blocks = skip * SQUASHFS_META_INDEXES;
while (blocks) {
int block = blocks > (SIZE >> 2) ? (SIZE >> 2) :
blocks;
int res = read_block_index(inode->i_sb, block,
block_list, &cur_index_block,
&cur_offset);
if (res == -1)
goto failed;
cur_data_block += res;
blocks -= block;
}
meta_entry = &meta->meta_entry[i - meta->offset];
meta_entry->index_block = cur_index_block - sblk->inode_table_start;
meta_entry->offset = cur_offset;
meta_entry->data_block = cur_data_block;
meta->entries ++;
offset ++;
}
TRACE("get_meta_index: meta->offset %d, meta->entries %d\n",
meta->offset, meta->entries);
release_meta_index(inode, meta);
}
all_done:
*index_block = cur_index_block;
*index_offset = cur_offset;
*data_block = cur_data_block;
return offset * SQUASHFS_META_INDEXES * skip;
failed:
release_meta_index(inode, meta);
return -1;
}
static long long read_blocklist(struct inode *inode, int index,
int readahead_blks, char *block_list,
unsigned short **block_p, unsigned int *bsize)
{
long long block_ptr;
int offset;
long long block;
int res = get_meta_index(inode, index, &block_ptr, &offset, &block,
block_list);
TRACE("read_blocklist: res %d, index %d, block_ptr 0x%llx, offset"
" 0x%x, block 0x%llx\n", res, index, block_ptr, offset,
block);
if(res == -1)
goto failure;
index -= res;
while ( index ) {
int blocks = index > (SIZE >> 2) ? (SIZE >> 2) : index;
int res = read_block_index(inode->i_sb, blocks, block_list,
&block_ptr, &offset);
if (res == -1)
goto failure;
block += res;
index -= blocks;
}
if (read_block_index(inode->i_sb, 1, block_list,
&block_ptr, &offset) == -1)
goto failure;
*bsize = *((unsigned int *) block_list);
return block;
failure:
return 0;
}
static int squashfs_readpage(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
struct squashfs_sb_info *msblk = &inode->i_sb->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
unsigned char block_list[SIZE];
long long block;
unsigned int bsize, i = 0, bytes = 0, byte_offset = 0;
int index = page->index >> (sblk->block_log - PAGE_CACHE_SHIFT);
void *pageaddr;
struct squashfs_fragment_cache *fragment = NULL;
char *data_ptr = msblk->read_page;
int mask = (1 << (sblk->block_log - PAGE_CACHE_SHIFT)) - 1;
int start_index = page->index & ~mask;
int end_index = start_index | mask;
TRACE("Entered squashfs_readpage, page index %lx, start block %llx\n",
page->index,
SQUASHFS_I(inode)->start_block);
if (page->index >= ((i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT))
goto skip_read;
if (SQUASHFS_I(inode)->u.s1.fragment_start_block == SQUASHFS_INVALID_BLK
|| index < (i_size_read(inode) >>
sblk->block_log)) {
if ((block = (msblk->read_blocklist)(inode, index, 1,
block_list, NULL, &bsize)) == 0)
goto skip_read;
down(&msblk->read_page_mutex);
if (!(bytes = squashfs_read_data(inode->i_sb, msblk->read_page,
block, bsize, NULL))) {
ERROR("Unable to read page, block %llx, size %x\n", block,
bsize);
up(&msblk->read_page_mutex);
goto skip_read;
}
} else {
if ((fragment = get_cached_fragment(inode->i_sb,
SQUASHFS_I(inode)->
u.s1.fragment_start_block,
SQUASHFS_I(inode)->u.s1.fragment_size))
== NULL) {
ERROR("Unable to read page, block %llx, size %x\n",
SQUASHFS_I(inode)->
u.s1.fragment_start_block,
(int) SQUASHFS_I(inode)->
u.s1.fragment_size);
goto skip_read;
}
bytes = SQUASHFS_I(inode)->u.s1.fragment_offset +
(i_size_read(inode) & (sblk->block_size
- 1));
byte_offset = SQUASHFS_I(inode)->u.s1.fragment_offset;
data_ptr = fragment->data;
}
for (i = start_index; i <= end_index && byte_offset < bytes;
i++, byte_offset += PAGE_CACHE_SIZE) {
struct page *push_page;
int available_bytes = (bytes - byte_offset) > PAGE_CACHE_SIZE ?
PAGE_CACHE_SIZE : bytes - byte_offset;
TRACE("bytes %d, i %d, byte_offset %d, available_bytes %d\n",
bytes, i, byte_offset, available_bytes);
if (i == page->index) {
pageaddr = kmap_atomic(page, KM_USER0);
memcpy(pageaddr, data_ptr + byte_offset,
available_bytes);
memset(pageaddr + available_bytes, 0,
PAGE_CACHE_SIZE - available_bytes);
kunmap_atomic(pageaddr, KM_USER0);
flush_dcache_page(page);
SetPageUptodate(page);
UnlockPage(page);
} else if ((push_page =
grab_cache_page_nowait(page->mapping, i))) {
pageaddr = kmap_atomic(push_page, KM_USER0);
memcpy(pageaddr, data_ptr + byte_offset,
available_bytes);
memset(pageaddr + available_bytes, 0,
PAGE_CACHE_SIZE - available_bytes);
kunmap_atomic(pageaddr, KM_USER0);
flush_dcache_page(push_page);
SetPageUptodate(push_page);
UnlockPage(push_page);
page_cache_release(push_page);
}
}
if (SQUASHFS_I(inode)->u.s1.fragment_start_block == SQUASHFS_INVALID_BLK
|| index < (i_size_read(inode) >>
sblk->block_log))
up(&msblk->read_page_mutex);
else
release_cached_fragment(msblk, fragment);
return 0;
skip_read:
pageaddr = kmap_atomic(page, KM_USER0);
memset(pageaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
kunmap_atomic(pageaddr, KM_USER0);
flush_dcache_page(page);
SetPageUptodate(page);
UnlockPage(page);
return 0;
}
static int squashfs_readpage4K(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
struct squashfs_sb_info *msblk = &inode->i_sb->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
unsigned char block_list[SIZE];
long long block;
unsigned int bsize, bytes = 0;
void *pageaddr;
TRACE("Entered squashfs_readpage4K, page index %lx, start block %llx\n",
page->index,
SQUASHFS_I(inode)->start_block);
if (page->index >= ((i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT)) {
pageaddr = kmap_atomic(page, KM_USER0);
goto skip_read;
}
if (SQUASHFS_I(inode)->u.s1.fragment_start_block == SQUASHFS_INVALID_BLK
|| page->index < (i_size_read(inode) >>
sblk->block_log)) {
block = (msblk->read_blocklist)(inode, page->index, 1,
block_list, NULL, &bsize);
down(&msblk->read_page_mutex);
bytes = squashfs_read_data(inode->i_sb, msblk->read_page, block,
bsize, NULL);
pageaddr = kmap_atomic(page, KM_USER0);
if (bytes)
memcpy(pageaddr, msblk->read_page, bytes);
else
ERROR("Unable to read page, block %llx, size %x\n",
block, bsize);
up(&msblk->read_page_mutex);
} else {
struct squashfs_fragment_cache *fragment =
get_cached_fragment(inode->i_sb,
SQUASHFS_I(inode)->
u.s1.fragment_start_block,
SQUASHFS_I(inode)-> u.s1.fragment_size);
pageaddr = kmap_atomic(page, KM_USER0);
if (fragment) {
bytes = i_size_read(inode) & (sblk->block_size - 1);
memcpy(pageaddr, fragment->data + SQUASHFS_I(inode)->
u.s1.fragment_offset, bytes);
release_cached_fragment(msblk, fragment);
} else
ERROR("Unable to read page, block %llx, size %x\n",
SQUASHFS_I(inode)->
u.s1.fragment_start_block, (int)
SQUASHFS_I(inode)-> u.s1.fragment_size);
}
skip_read:
memset(pageaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
kunmap_atomic(pageaddr, KM_USER0);
flush_dcache_page(page);
SetPageUptodate(page);
UnlockPage(page);
return 0;
}
static int get_dir_index_using_offset(struct super_block *s, long long
*next_block, unsigned int *next_offset,
long long index_start,
unsigned int index_offset, int i_count,
long long f_pos)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
int i, length = 0;
struct squashfs_dir_index index;
TRACE("Entered get_dir_index_using_offset, i_count %d, f_pos %d\n",
i_count, (unsigned int) f_pos);
f_pos -= 3;
if (f_pos == 0)
goto finish;
for (i = 0; i < i_count; i++) {
if (msblk->swap) {
struct squashfs_dir_index sindex;
squashfs_get_cached_block(s, (char *) &sindex,
index_start, index_offset,
sizeof(sindex), &index_start,
&index_offset);
SQUASHFS_SWAP_DIR_INDEX(&index, &sindex);
} else
squashfs_get_cached_block(s, (char *) &index,
index_start, index_offset,
sizeof(index), &index_start,
&index_offset);
if (index.index > f_pos)
break;
squashfs_get_cached_block(s, NULL, index_start, index_offset,
index.size + 1, &index_start,
&index_offset);
length = index.index;
*next_block = index.start_block + sblk->directory_table_start;
}
*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
finish:
return length + 3;
}
static int get_dir_index_using_name(struct super_block *s, long long
*next_block, unsigned int *next_offset,
long long index_start,
unsigned int index_offset, int i_count,
const char *name, int size)
{
struct squashfs_sb_info *msblk = &s->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
int i, length = 0;
char buffer[sizeof(struct squashfs_dir_index) + SQUASHFS_NAME_LEN + 1];
struct squashfs_dir_index *index = (struct squashfs_dir_index *) buffer;
char str[SQUASHFS_NAME_LEN + 1];
TRACE("Entered get_dir_index_using_name, i_count %d\n", i_count);
strncpy(str, name, size);
str[size] = '\0';
for (i = 0; i < i_count; i++) {
if (msblk->swap) {
struct squashfs_dir_index sindex;
squashfs_get_cached_block(s, (char *) &sindex,
index_start, index_offset,
sizeof(sindex), &index_start,
&index_offset);
SQUASHFS_SWAP_DIR_INDEX(index, &sindex);
} else
squashfs_get_cached_block(s, (char *) index,
index_start, index_offset,
sizeof(struct squashfs_dir_index),
&index_start, &index_offset);
squashfs_get_cached_block(s, index->name, index_start,
index_offset, index->size + 1,
&index_start, &index_offset);
index->name[index->size + 1] = '\0';
if (strcmp(index->name, str) > 0)
break;
length = index->index;
*next_block = index->start_block + sblk->directory_table_start;
}
*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
return length + 3;
}
static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
{
struct inode *i = file->f_dentry->d_inode;
struct squashfs_sb_info *msblk = &i->i_sb->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
long long next_block = SQUASHFS_I(i)->start_block +
sblk->directory_table_start;
int next_offset = SQUASHFS_I(i)->offset, length = 0,
dir_count;
struct squashfs_dir_header dirh;
char buffer[sizeof(struct squashfs_dir_entry) + SQUASHFS_NAME_LEN + 1];
struct squashfs_dir_entry *dire = (struct squashfs_dir_entry *) buffer;
TRACE("Entered squashfs_readdir [%llx:%x]\n", next_block, next_offset);
while(file->f_pos < 3) {
char *name;
int size, i_ino;
if(file->f_pos == 0) {
name = ".";
size = 1;
i_ino = i->i_ino;
} else {
name = "..";
size = 2;
i_ino = SQUASHFS_I(i)->u.s2.parent_inode;
}
TRACE("Calling filldir(%x, %s, %d, %d, %d, %d)\n",
(unsigned int) dirent, name, size, (int)
file->f_pos, i_ino,
squashfs_filetype_table[1]);
if (filldir(dirent, name, size,
file->f_pos, i_ino,
squashfs_filetype_table[1]) < 0) {
TRACE("Filldir returned less than 0\n");
goto finish;
}
file->f_pos += size;
}
length = get_dir_index_using_offset(i->i_sb, &next_block, &next_offset,
SQUASHFS_I(i)->u.s2.directory_index_start,
SQUASHFS_I(i)->u.s2.directory_index_offset,
SQUASHFS_I(i)->u.s2.directory_index_count,
file->f_pos);
while (length < i_size_read(i)) {
/* read directory header */
if (msblk->swap) {
struct squashfs_dir_header sdirh;
if (!squashfs_get_cached_block(i->i_sb, (char *) &sdirh,
next_block, next_offset, sizeof(sdirh),
&next_block, &next_offset))
goto failed_read;
length += sizeof(sdirh);
SQUASHFS_SWAP_DIR_HEADER(&dirh, &sdirh);
} else {
if (!squashfs_get_cached_block(i->i_sb, (char *) &dirh,
next_block, next_offset, sizeof(dirh),
&next_block, &next_offset))
goto failed_read;
length += sizeof(dirh);
}
dir_count = dirh.count + 1;
while (dir_count--) {
if (msblk->swap) {
struct squashfs_dir_entry sdire;
if (!squashfs_get_cached_block(i->i_sb, (char *)
&sdire, next_block, next_offset,
sizeof(sdire), &next_block,
&next_offset))
goto failed_read;
length += sizeof(sdire);
SQUASHFS_SWAP_DIR_ENTRY(dire, &sdire);
} else {
if (!squashfs_get_cached_block(i->i_sb, (char *)
dire, next_block, next_offset,
sizeof(*dire), &next_block,
&next_offset))
goto failed_read;
length += sizeof(*dire);
}
if (!squashfs_get_cached_block(i->i_sb, dire->name,
next_block, next_offset,
dire->size + 1, &next_block,
&next_offset))
goto failed_read;
length += dire->size + 1;
if (file->f_pos >= length)
continue;
dire->name[dire->size + 1] = '\0';
TRACE("Calling filldir(%x, %s, %d, %d, %x:%x, %d, %d)\n",
(unsigned int) dirent, dire->name,
dire->size + 1, (int) file->f_pos,
dirh.start_block, dire->offset,
dirh.inode_number + dire->inode_number,
squashfs_filetype_table[dire->type]);
if (filldir(dirent, dire->name, dire->size + 1,
file->f_pos,
dirh.inode_number + dire->inode_number,
squashfs_filetype_table[dire->type])
< 0) {
TRACE("Filldir returned less than 0\n");
goto finish;
}
file->f_pos = length;
}
}
finish:
return 0;
failed_read:
ERROR("Unable to read directory block [%llx:%x]\n", next_block,
next_offset);
return 0;
}
static struct dentry *squashfs_lookup(struct inode *i, struct dentry *dentry)
{
const unsigned char *name = dentry->d_name.name;
int len = dentry->d_name.len;
struct inode *inode = NULL;
struct squashfs_sb_info *msblk = &i->i_sb->u.squashfs_sb;
struct squashfs_super_block *sblk = &msblk->sblk;
long long next_block = SQUASHFS_I(i)->start_block +
sblk->directory_table_start;
int next_offset = SQUASHFS_I(i)->offset, length = 0,
dir_count;
struct squashfs_dir_header dirh;
char buffer[sizeof(struct squashfs_dir_entry) + SQUASHFS_NAME_LEN];
struct squashfs_dir_entry *dire = (struct squashfs_dir_entry *) buffer;
TRACE("Entered squashfs_lookup [%llx:%x]\n", next_block, next_offset);
if (len > SQUASHFS_NAME_LEN)
goto exit_loop;
length = get_dir_index_using_name(i->i_sb, &next_block, &next_offset,
SQUASHFS_I(i)->u.s2.directory_index_start,
SQUASHFS_I(i)->u.s2.directory_index_offset,
SQUASHFS_I(i)->u.s2.directory_index_count, name,
len);
while (length < i_size_read(i)) {
/* read directory header */
if (msblk->swap) {
struct squashfs_dir_header sdirh;
if (!squashfs_get_cached_block(i->i_sb, (char *) &sdirh,
next_block, next_offset, sizeof(sdirh),
&next_block, &next_offset))
goto failed_read;
length += sizeof(sdirh);
SQUASHFS_SWAP_DIR_HEADER(&dirh, &sdirh);
} else {
if (!squashfs_get_cached_block(i->i_sb, (char *) &dirh,
next_block, next_offset, sizeof(dirh),
&next_block, &next_offset))
goto failed_read;
length += sizeof(dirh);
}
dir_count = dirh.count + 1;
while (dir_count--) {
if (msblk->swap) {
struct squashfs_dir_entry sdire;
if (!squashfs_get_cached_block(i->i_sb, (char *)
&sdire, next_block,next_offset,
sizeof(sdire), &next_block,
&next_offset))
goto failed_read;
length += sizeof(sdire);
SQUASHFS_SWAP_DIR_ENTRY(dire, &sdire);
} else {
if (!squashfs_get_cached_block(i->i_sb, (char *)
dire, next_block,next_offset,
sizeof(*dire), &next_block,
&next_offset))
goto failed_read;
length += sizeof(*dire);
}
if (!squashfs_get_cached_block(i->i_sb, dire->name,
next_block, next_offset, dire->size + 1,
&next_block, &next_offset))
goto failed_read;
length += dire->size + 1;
if (name[0] < dire->name[0])
goto exit_loop;
if ((len == dire->size + 1) && !strncmp(name,
dire->name, len)) {
squashfs_inode_t ino =
SQUASHFS_MKINODE(dirh.start_block,
dire->offset);
TRACE("calling squashfs_iget for directory "
"entry %s, inode %x:%x, %d\n", name,
dirh.start_block, dire->offset,
dirh.inode_number + dire->inode_number);
inode = (msblk->iget)(i->i_sb, ino);
goto exit_loop;
}
}
}
exit_loop:
d_add(dentry, inode);
return ERR_PTR(0);
failed_read:
ERROR("Unable to read directory block [%llx:%x]\n", next_block,
next_offset);
goto exit_loop;
}
static void squashfs_put_super(struct super_block *s)
{
int i;
struct squashfs_sb_info *sbi = &s->u.squashfs_sb;
if (sbi->block_cache)
for (i = 0; i < SQUASHFS_CACHED_BLKS; i++)
if (sbi->block_cache[i].block !=
SQUASHFS_INVALID_BLK)
kfree(sbi->block_cache[i].data);
if (sbi->fragment)
for (i = 0; i < SQUASHFS_CACHED_FRAGMENTS; i++)
SQUASHFS_FREE(sbi->fragment[i].data);
kfree(sbi->fragment);
kfree(sbi->block_cache);
kfree(sbi->read_data);
kfree(sbi->read_page);
kfree(sbi->uid);
kfree(sbi->fragment_index);
kfree(sbi->fragment_index_2);
kfree(sbi->meta_index);
vfree(sbi->stream.workspace);
sbi->block_cache = NULL;
sbi->uid = NULL;
sbi->read_data = NULL;
sbi->read_page = NULL;
sbi->fragment = NULL;
sbi->fragment_index = NULL;
sbi->fragment_index_2 = NULL;
sbi->meta_index = NULL;
sbi->stream.workspace = NULL;
}
static int __init init_squashfs_fs(void)
{
printk(KERN_INFO "squashfs: version 3.1 (2006/08/15) "
"Phillip Lougher\n");
return register_filesystem(&squashfs_fs_type);
}
static void __exit exit_squashfs_fs(void)
{
unregister_filesystem(&squashfs_fs_type);
}
EXPORT_NO_SYMBOLS;
module_init(init_squashfs_fs);
module_exit(exit_squashfs_fs);
MODULE_DESCRIPTION("squashfs 3.1, a compressed read-only filesystem");
MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
MODULE_LICENSE("GPL");
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