M7350v1_en_gpl

kernel/fs/squashfs/Kconfig

@@ -0,0 +1,123 @@
+config SQUASHFS
+	tristate "SquashFS 4.0 - Squashed file system support"
+	depends on BLOCK
+	help
+	  Saying Y here includes support for SquashFS 4.0 (a Compressed
+	  Read-Only File System).  Squashfs is a highly compressed read-only
+	  filesystem for Linux.  It uses zlib, lzo or xz compression to
+	  compress both files, inodes and directories.  Inodes in the system
+	  are very small and all blocks are packed to minimise data overhead.
+	  Block sizes greater than 4K are supported up to a maximum of 1 Mbytes
+	  (default block size 128K).  SquashFS 4.0 supports 64 bit filesystems
+	  and files (larger than 4GB), full uid/gid information, hard links and
+	  timestamps.
+
+	  Squashfs is intended for general read-only filesystem use, for
+	  archival use (i.e. in cases where a .tar.gz file may be used), and in
+	  embedded systems where low overhead is needed.  Further information
+	  and tools are available from http://squashfs.sourceforge.net.
+
+	  If you want to compile this as a module ( = code which can be
+	  inserted in and removed from the running kernel whenever you want),
+	  say M here.  The module will be called squashfs.  Note that the root
+	  file system (the one containing the directory /) cannot be compiled
+	  as a module.
+
+	  If unsure, say N.
+
+config SQUASHFS_XATTR
+	bool "Squashfs XATTR support"
+	depends on SQUASHFS
+	help
+	  Saying Y here includes support for extended attributes (xattrs).
+	  Xattrs are name:value pairs associated with inodes by
+	  the kernel or by users (see the attr(5) manual page).
+
+	  If unsure, say N.
+
+config SQUASHFS_ZLIB
+	bool "Include support for ZLIB compressed file systems"
+	depends on SQUASHFS
+	select ZLIB_INFLATE
+	default y
+	help
+	  ZLIB compression is the standard compression used by Squashfs
+	  file systems.  It offers a good trade-off between compression
+	  achieved and the amount of CPU time and memory necessary to
+	  compress and decompress.
+
+	  If unsure, say Y.
+
+config SQUASHFS_LZO
+	bool "Include support for LZO compressed file systems"
+	depends on SQUASHFS
+	select LZO_DECOMPRESS
+	help
+	  Saying Y here includes support for reading Squashfs file systems
+	  compressed with LZO compression.  LZO compression is mainly
+	  aimed at embedded systems with slower CPUs where the overheads
+	  of zlib are too high.
+
+	  LZO is not the standard compression used in Squashfs and so most
+	  file systems will be readable without selecting this option.
+
+	  If unsure, say N.
+
+config SQUASHFS_XZ
+	bool "Include support for XZ compressed file systems"
+	depends on SQUASHFS
+	select XZ_DEC
+	help
+	  Saying Y here includes support for reading Squashfs file systems
+	  compressed with XZ compression.  XZ gives better compression than
+	  the default zlib compression, at the expense of greater CPU and
+	  memory overhead.
+
+	  XZ is not the standard compression used in Squashfs and so most
+	  file systems will be readable without selecting this option.
+
+	  If unsure, say N.
+
+config SQUASHFS_4K_DEVBLK_SIZE
+	bool "Use 4K device block size?"
+	depends on SQUASHFS
+	help
+	  By default Squashfs sets the dev block size (sb_min_blocksize)
+	  to 1K or the smallest block size supported by the block device
+	  (if larger).  This, because blocks are packed together and
+	  unaligned in Squashfs, should reduce latency.
+
+	  This, however, gives poor performance on MTD NAND devices where
+	  the optimal I/O size is 4K (even though the devices can support
+	  smaller block sizes).
+
+	  Using a 4K device block size may also improve overall I/O
+	  performance for some file access patterns (e.g. sequential
+	  accesses of files in filesystem order) on all media.
+
+	  Setting this option will force Squashfs to use a 4K device block
+	  size by default.
+
+	  If unsure, say N.
+
+config SQUASHFS_EMBEDDED
+	bool "Additional option for memory-constrained systems"
+	depends on SQUASHFS
+	help
+	  Saying Y here allows you to specify cache size.
+
+	  If unsure, say N.
+
+config SQUASHFS_FRAGMENT_CACHE_SIZE
+	int "Number of fragments cached" if SQUASHFS_EMBEDDED
+	depends on SQUASHFS
+	default "3"
+	help
+	  By default SquashFS caches the last 3 fragments read from
+	  the filesystem.  Increasing this amount may mean SquashFS
+	  has to re-read fragments less often from disk, at the expense
+	  of extra system memory.  Decreasing this amount will mean
+	  SquashFS uses less memory at the expense of extra reads from disk.
+
+	  Note there must be at least one cached fragment.  Anything
+	  much more than three will probably not make much difference.

kernel/fs/squashfs/Makefile

@@ -0,0 +1,11 @@
+#
+# Makefile for the linux squashfs routines.
+#
+
+obj-$(CONFIG_SQUASHFS) += squashfs.o
+squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
+squashfs-y += namei.o super.o symlink.o decompressor.o
+squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o
+squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
+squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
+squashfs-$(CONFIG_SQUASHFS_ZLIB) += zlib_wrapper.o

kernel/fs/squashfs/block.c

@@ -0,0 +1,211 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * block.c
+ */
+
+/*
+ * This file implements the low-level routines to read and decompress
+ * datablocks and metadata blocks.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+/*
+ * Read the metadata block length, this is stored in the first two
+ * bytes of the metadata block.
+ */
+static struct buffer_head *get_block_length(struct super_block *sb,
+			u64 *cur_index, int *offset, int *length)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	struct buffer_head *bh;
+
+	bh = sb_bread(sb, *cur_index);
+	if (bh == NULL)
+		return NULL;
+
+	if (msblk->devblksize - *offset == 1) {
+		*length = (unsigned char) bh->b_data[*offset];
+		put_bh(bh);
+		bh = sb_bread(sb, ++(*cur_index));
+		if (bh == NULL)
+			return NULL;
+		*length |= (unsigned char) bh->b_data[0] << 8;
+		*offset = 1;
+	} else {
+		*length = (unsigned char) bh->b_data[*offset] |
+			(unsigned char) bh->b_data[*offset + 1] << 8;
+		*offset += 2;
+
+		if (*offset == msblk->devblksize) {
+			put_bh(bh);
+			bh = sb_bread(sb, ++(*cur_index));
+			if (bh == NULL)
+				return NULL;
+			*offset = 0;
+		}
+	}
+
+	return bh;
+}
+
+
+/*
+ * Read and decompress a metadata block or datablock.  Length is non-zero
+ * if a datablock is being read (the size is stored elsewhere in the
+ * filesystem), otherwise the length is obtained from the first two bytes of
+ * the metadata block.  A bit in the length field indicates if the block
+ * is stored uncompressed in the filesystem (usually because compression
+ * generated a larger block - this does occasionally happen with compression
+ * algorithms).
+ */
+int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
+			int length, u64 *next_index, int srclength, int pages)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	struct buffer_head **bh;
+	int offset = index & ((1 << msblk->devblksize_log2) - 1);
+	u64 cur_index = index >> msblk->devblksize_log2;
+	int bytes, compressed, b = 0, k = 0, page = 0, avail;
+
+	bh = kcalloc(((srclength + msblk->devblksize - 1)
+		>> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL);
+	if (bh == NULL)
+		return -ENOMEM;
+
+	if (length) {
+		/*
+		 * Datablock.
+		 */
+		bytes = -offset;
+		compressed = SQUASHFS_COMPRESSED_BLOCK(length);
+		length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
+		if (next_index)
+			*next_index = index + length;
+
+		TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
+			index, compressed ? "" : "un", length, srclength);
+
+		if (length < 0 || length > srclength ||
+				(index + length) > msblk->bytes_used)
+			goto read_failure;
+
+		for (b = 0; bytes < length; b++, cur_index++) {
+			bh[b] = sb_getblk(sb, cur_index);
+			if (bh[b] == NULL)
+				goto block_release;
+			bytes += msblk->devblksize;
+		}
+		ll_rw_block(READ, b, bh);
+	} else {
+		/*
+		 * Metadata block.
+		 */
+		if ((index + 2) > msblk->bytes_used)
+			goto read_failure;
+
+		bh[0] = get_block_length(sb, &cur_index, &offset, &length);
+		if (bh[0] == NULL)
+			goto read_failure;
+		b = 1;
+
+		bytes = msblk->devblksize - offset;
+		compressed = SQUASHFS_COMPRESSED(length);
+		length = SQUASHFS_COMPRESSED_SIZE(length);
+		if (next_index)
+			*next_index = index + length + 2;
+
+		TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
+				compressed ? "" : "un", length);
+
+		if (length < 0 || length > srclength ||
+					(index + length) > msblk->bytes_used)
+			goto block_release;
+
+		for (; bytes < length; b++) {
+			bh[b] = sb_getblk(sb, ++cur_index);
+			if (bh[b] == NULL)
+				goto block_release;
+			bytes += msblk->devblksize;
+		}
+		ll_rw_block(READ, b - 1, bh + 1);
+	}
+
+	if (compressed) {
+		length = squashfs_decompress(msblk, buffer, bh, b, offset,
+			 length, srclength, pages);
+		if (length < 0)
+			goto read_failure;
+	} else {
+		/*
+		 * Block is uncompressed.
+		 */
+		int i, in, pg_offset = 0;
+
+		for (i = 0; i < b; i++) {
+			wait_on_buffer(bh[i]);
+			if (!buffer_uptodate(bh[i]))
+				goto block_release;
+		}
+
+		for (bytes = length; k < b; k++) {
+			in = min(bytes, msblk->devblksize - offset);
+			bytes -= in;
+			while (in) {
+				if (pg_offset == PAGE_CACHE_SIZE) {
+					page++;
+					pg_offset = 0;
+				}
+				avail = min_t(int, in, PAGE_CACHE_SIZE -
+						pg_offset);
+				memcpy(buffer[page] + pg_offset,
+						bh[k]->b_data + offset, avail);
+				in -= avail;
+				pg_offset += avail;
+				offset += avail;
+			}
+			offset = 0;
+			put_bh(bh[k]);
+		}
+	}
+
+	kfree(bh);
+	return length;
+
+block_release:
+	for (; k < b; k++)
+		put_bh(bh[k]);
+
+read_failure:
+	ERROR("squashfs_read_data failed to read block 0x%llx\n",
+					(unsigned long long) index);
+	kfree(bh);
+	return -EIO;
+}

kernel/fs/squashfs/cache.c

@@ -0,0 +1,440 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * cache.c
+ */
+
+/*
+ * Blocks in Squashfs are compressed.  To avoid repeatedly decompressing
+ * recently accessed data Squashfs uses two small metadata and fragment caches.
+ *
+ * This file implements a generic cache implementation used for both caches,
+ * plus functions layered ontop of the generic cache implementation to
+ * access the metadata and fragment caches.
+ *
+ * To avoid out of memory and fragmentation issues with vmalloc the cache
+ * uses sequences of kmalloced PAGE_CACHE_SIZE buffers.
+ *
+ * It should be noted that the cache is not used for file datablocks, these
+ * are decompressed and cached in the page-cache in the normal way.  The
+ * cache is only used to temporarily cache fragment and metadata blocks
+ * which have been read as as a result of a metadata (i.e. inode or
+ * directory) or fragment access.  Because metadata and fragments are packed
+ * together into blocks (to gain greater compression) the read of a particular
+ * piece of metadata or fragment will retrieve other metadata/fragments which
+ * have been packed with it, these because of locality-of-reference may be read
+ * in the near future. Temporarily caching them ensures they are available for
+ * near future access without requiring an additional read and decompress.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/pagemap.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+
+/*
+ * Look-up block in cache, and increment usage count.  If not in cache, read
+ * and decompress it from disk.
+ */
+struct squashfs_cache_entry *squashfs_cache_get(struct super_block *sb,
+	struct squashfs_cache *cache, u64 block, int length)
+{
+	int i, n;
+	struct squashfs_cache_entry *entry;
+
+	spin_lock(&cache->lock);
+
+	while (1) {
+		for (i = cache->curr_blk, n = 0; n < cache->entries; n++) {
+			if (cache->entry[i].block == block) {
+				cache->curr_blk = i;
+				break;
+			}
+			i = (i + 1) % cache->entries;
+		}
+
+		if (n == cache->entries) {
+			/*
+			 * Block not in cache, if all cache entries are used
+			 * go to sleep waiting for one to become available.
+			 */
+			if (cache->unused == 0) {
+				cache->num_waiters++;
+				spin_unlock(&cache->lock);
+				wait_event(cache->wait_queue, cache->unused);
+				spin_lock(&cache->lock);
+				cache->num_waiters--;
+				continue;
+			}
+
+			/*
+			 * At least one unused cache entry.  A simple
+			 * round-robin strategy is used to choose the entry to
+			 * be evicted from the cache.
+			 */
+			i = cache->next_blk;
+			for (n = 0; n < cache->entries; n++) {
+				if (cache->entry[i].refcount == 0)
+					break;
+				i = (i + 1) % cache->entries;
+			}
+
+			cache->next_blk = (i + 1) % cache->entries;
+			entry = &cache->entry[i];
+
+			/*
+			 * Initialise chosen cache entry, and fill it in from
+			 * disk.
+			 */
+			cache->unused--;
+			entry->block = block;
+			entry->refcount = 1;
+			entry->pending = 1;
+			entry->num_waiters = 0;
+			entry->error = 0;
+			spin_unlock(&cache->lock);
+
+			entry->length = squashfs_read_data(sb, entry->data,
+				block, length, &entry->next_index,
+				cache->block_size, cache->pages);
+
+			spin_lock(&cache->lock);
+
+			if (entry->length < 0)
+				entry->error = entry->length;
+
+			entry->pending = 0;
+
+			/*
+			 * While filling this entry one or more other processes
+			 * have looked it up in the cache, and have slept
+			 * waiting for it to become available.
+			 */
+			if (entry->num_waiters) {
+				spin_unlock(&cache->lock);
+				wake_up_all(&entry->wait_queue);
+			} else
+				spin_unlock(&cache->lock);
+
+			goto out;
+		}
+
+		/*
+		 * Block already in cache.  Increment refcount so it doesn't
+		 * get reused until we're finished with it, if it was
+		 * previously unused there's one less cache entry available
+		 * for reuse.
+		 */
+		entry = &cache->entry[i];
+		if (entry->refcount == 0)
+			cache->unused--;
+		entry->refcount++;
+
+		/*
+		 * If the entry is currently being filled in by another process
+		 * go to sleep waiting for it to become available.
+		 */
+		if (entry->pending) {
+			entry->num_waiters++;
+			spin_unlock(&cache->lock);
+			wait_event(entry->wait_queue, !entry->pending);
+		} else
+			spin_unlock(&cache->lock);
+
+		goto out;
+	}
+
+out:
+	TRACE("Got %s %d, start block %lld, refcount %d, error %d\n",
+		cache->name, i, entry->block, entry->refcount, entry->error);
+
+	if (entry->error)
+		ERROR("Unable to read %s cache entry [%llx]\n", cache->name,
+							block);
+	return entry;
+}
+
+
+/*
+ * Release cache entry, once usage count is zero it can be reused.
+ */
+void squashfs_cache_put(struct squashfs_cache_entry *entry)
+{
+	struct squashfs_cache *cache = entry->cache;
+
+	spin_lock(&cache->lock);
+	entry->refcount--;
+	if (entry->refcount == 0) {
+		cache->unused++;
+		/*
+		 * If there's any processes waiting for a block to become
+		 * available, wake one up.
+		 */
+		if (cache->num_waiters) {
+			spin_unlock(&cache->lock);
+			wake_up(&cache->wait_queue);
+			return;
+		}
+	}
+	spin_unlock(&cache->lock);
+}
+
+/*
+ * Delete cache reclaiming all kmalloced buffers.
+ */
+void squashfs_cache_delete(struct squashfs_cache *cache)
+{
+	int i, j;
+
+	if (cache == NULL)
+		return;
+
+	for (i = 0; i < cache->entries; i++) {
+		if (cache->entry[i].data) {
+			for (j = 0; j < cache->pages; j++)
+				kfree(cache->entry[i].data[j]);
+			kfree(cache->entry[i].data);
+		}
+	}
+
+	kfree(cache->entry);
+	kfree(cache);
+}
+
+
+/*
+ * Initialise cache allocating the specified number of entries, each of
+ * size block_size.  To avoid vmalloc fragmentation issues each entry
+ * is allocated as a sequence of kmalloced PAGE_CACHE_SIZE buffers.
+ */
+struct squashfs_cache *squashfs_cache_init(char *name, int entries,
+	int block_size)
+{
+	int i, j;
+	struct squashfs_cache *cache = kzalloc(sizeof(*cache), GFP_KERNEL);
+
+	if (cache == NULL) {
+		ERROR("Failed to allocate %s cache\n", name);
+		return NULL;
+	}
+
+	cache->entry = kcalloc(entries, sizeof(*(cache->entry)), GFP_KERNEL);
+	if (cache->entry == NULL) {
+		ERROR("Failed to allocate %s cache\n", name);
+		goto cleanup;
+	}
+
+	cache->curr_blk = 0;
+	cache->next_blk = 0;
+	cache->unused = entries;
+	cache->entries = entries;
+	cache->block_size = block_size;
+	cache->pages = block_size >> PAGE_CACHE_SHIFT;
+	cache->pages = cache->pages ? cache->pages : 1;
+	cache->name = name;
+	cache->num_waiters = 0;
+	spin_lock_init(&cache->lock);
+	init_waitqueue_head(&cache->wait_queue);
+
+	for (i = 0; i < entries; i++) {
+		struct squashfs_cache_entry *entry = &cache->entry[i];
+
+		init_waitqueue_head(&cache->entry[i].wait_queue);
+		entry->cache = cache;
+		entry->block = SQUASHFS_INVALID_BLK;
+		entry->data = kcalloc(cache->pages, sizeof(void *), GFP_KERNEL);
+		if (entry->data == NULL) {
+			ERROR("Failed to allocate %s cache entry\n", name);
+			goto cleanup;
+		}
+
+		for (j = 0; j < cache->pages; j++) {
+			entry->data[j] = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
+			if (entry->data[j] == NULL) {
+				ERROR("Failed to allocate %s buffer\n", name);
+				goto cleanup;
+			}
+		}
+	}
+
+	return cache;
+
+cleanup:
+	squashfs_cache_delete(cache);
+	return NULL;
+}
+
+
+/*
+ * Copy up to length bytes from cache entry to buffer starting at offset bytes
+ * into the cache entry.  If there's not length bytes then copy the number of
+ * bytes available.  In all cases return the number of bytes copied.
+ */
+int squashfs_copy_data(void *buffer, struct squashfs_cache_entry *entry,
+		int offset, int length)
+{
+	int remaining = length;
+
+	if (length == 0)
+		return 0;
+	else if (buffer == NULL)
+		return min(length, entry->length - offset);
+
+	while (offset < entry->length) {
+		void *buff = entry->data[offset / PAGE_CACHE_SIZE]
+				+ (offset % PAGE_CACHE_SIZE);
+		int bytes = min_t(int, entry->length - offset,
+				PAGE_CACHE_SIZE - (offset % PAGE_CACHE_SIZE));
+
+		if (bytes >= remaining) {
+			memcpy(buffer, buff, remaining);
+			remaining = 0;
+			break;
+		}
+
+		memcpy(buffer, buff, bytes);
+		buffer += bytes;
+		remaining -= bytes;
+		offset += bytes;
+	}
+
+	return length - remaining;
+}
+
+
+/*
+ * Read length bytes from metadata position <block, offset> (block is the
+ * start of the compressed block on disk, and offset is the offset into
+ * the block once decompressed).  Data is packed into consecutive blocks,
+ * and length bytes may require reading more than one block.
+ */
+int squashfs_read_metadata(struct super_block *sb, void *buffer,
+		u64 *block, int *offset, int length)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int bytes, res = length;
+	struct squashfs_cache_entry *entry;
+
+	TRACE("Entered squashfs_read_metadata [%llx:%x]\n", *block, *offset);
+
+	while (length) {
+		entry = squashfs_cache_get(sb, msblk->block_cache, *block, 0);
+		if (entry->error) {
+			res = entry->error;
+			goto error;
+		} else if (*offset >= entry->length) {
+			res = -EIO;
+			goto error;
+		}
+
+		bytes = squashfs_copy_data(buffer, entry, *offset, length);
+		if (buffer)
+			buffer += bytes;
+		length -= bytes;
+		*offset += bytes;
+
+		if (*offset == entry->length) {
+			*block = entry->next_index;
+			*offset = 0;
+		}
+
+		squashfs_cache_put(entry);
+	}
+
+	return res;
+
+error:
+	squashfs_cache_put(entry);
+	return res;
+}
+
+
+/*
+ * Look-up in the fragmment cache the fragment located at <start_block> in the
+ * filesystem.  If necessary read and decompress it from disk.
+ */
+struct squashfs_cache_entry *squashfs_get_fragment(struct super_block *sb,
+				u64 start_block, int length)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+
+	return squashfs_cache_get(sb, msblk->fragment_cache, start_block,
+		length);
+}
+
+
+/*
+ * Read and decompress the datablock located at <start_block> in the
+ * filesystem.  The cache is used here to avoid duplicating locking and
+ * read/decompress code.
+ */
+struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *sb,
+				u64 start_block, int length)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+
+	return squashfs_cache_get(sb, msblk->read_page, start_block, length);
+}
+
+
+/*
+ * Read a filesystem table (uncompressed sequence of bytes) from disk
+ */
+void *squashfs_read_table(struct super_block *sb, u64 block, int length)
+{
+	int pages = (length + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	int i, res;
+	void *table, *buffer, **data;
+
+	table = buffer = kmalloc(length, GFP_KERNEL);
+	if (table == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	data = kcalloc(pages, sizeof(void *), GFP_KERNEL);
+	if (data == NULL) {
+		res = -ENOMEM;
+		goto failed;
+	}
+
+	for (i = 0; i < pages; i++, buffer += PAGE_CACHE_SIZE)
+		data[i] = buffer;
+
+	res = squashfs_read_data(sb, data, block, length |
+		SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, length, pages);
+
+	kfree(data);
+
+	if (res < 0)
+		goto failed;
+
+	return table;
+
+failed:
+	kfree(table);
+	return ERR_PTR(res);
+}

kernel/fs/squashfs/decompressor.c

@@ -0,0 +1,116 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * decompressor.c
+ */
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "decompressor.h"
+#include "squashfs.h"
+
+/*
+ * This file (and decompressor.h) implements a decompressor framework for
+ * Squashfs, allowing multiple decompressors to be easily supported
+ */
+
+static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
+	NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
+};
+
+#ifndef CONFIG_SQUASHFS_LZO
+static const struct squashfs_decompressor squashfs_lzo_comp_ops = {
+	NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
+};
+#endif
+
+#ifndef CONFIG_SQUASHFS_XZ
+static const struct squashfs_decompressor squashfs_xz_comp_ops = {
+	NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0
+};
+#endif
+
+#ifndef CONFIG_SQUASHFS_ZLIB
+static const struct squashfs_decompressor squashfs_zlib_comp_ops = {
+	NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0
+};
+#endif
+
+static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
+	NULL, NULL, NULL, 0, "unknown", 0
+};
+
+static const struct squashfs_decompressor *decompressor[] = {
+	&squashfs_zlib_comp_ops,
+	&squashfs_lzo_comp_ops,
+	&squashfs_xz_comp_ops,
+	&squashfs_lzma_unsupported_comp_ops,
+	&squashfs_unknown_comp_ops
+};
+
+
+const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
+{
+	int i;
+
+	for (i = 0; decompressor[i]->id; i++)
+		if (id == decompressor[i]->id)
+			break;
+
+	return decompressor[i];
+}
+
+
+void *squashfs_decompressor_init(struct super_block *sb, unsigned short flags)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	void *strm, *buffer = NULL;
+	int length = 0;
+
+	/*
+	 * Read decompressor specific options from file system if present
+	 */
+	if (SQUASHFS_COMP_OPTS(flags)) {
+		buffer = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
+		if (buffer == NULL)
+			return ERR_PTR(-ENOMEM);
+
+		length = squashfs_read_data(sb, &buffer,
+			sizeof(struct squashfs_super_block), 0, NULL,
+			PAGE_CACHE_SIZE, 1);
+
+		if (length < 0) {
+			strm = ERR_PTR(length);
+			goto finished;
+		}
+	}
+
+	strm = msblk->decompressor->init(msblk, buffer, length);
+
+finished:
+	kfree(buffer);
+
+	return strm;
+}

kernel/fs/squashfs/decompressor.h

@@ -0,0 +1,63 @@
+#ifndef DECOMPRESSOR_H
+#define DECOMPRESSOR_H
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * decompressor.h
+ */
+
+struct squashfs_decompressor {
+	void	*(*init)(struct squashfs_sb_info *, void *, int);
+	void	(*free)(void *);
+	int	(*decompress)(struct squashfs_sb_info *, void **,
+		struct buffer_head **, int, int, int, int, int);
+	int	id;
+	char	*name;
+	int	supported;
+};
+
+static inline void squashfs_decompressor_free(struct squashfs_sb_info *msblk,
+	void *s)
+{
+	if (msblk->decompressor)
+		msblk->decompressor->free(s);
+}
+
+static inline int squashfs_decompress(struct squashfs_sb_info *msblk,
+	void **buffer, struct buffer_head **bh, int b, int offset, int length,
+	int srclength, int pages)
+{
+	return msblk->decompressor->decompress(msblk, buffer, bh, b, offset,
+		length, srclength, pages);
+}
+
+#ifdef CONFIG_SQUASHFS_XZ
+extern const struct squashfs_decompressor squashfs_xz_comp_ops;
+#endif
+
+#ifdef CONFIG_SQUASHFS_LZO
+extern const struct squashfs_decompressor squashfs_lzo_comp_ops;
+#endif
+
+#ifdef CONFIG_SQUASHFS_ZLIB
+extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
+#endif
+
+#endif

kernel/fs/squashfs/dir.c

@@ -0,0 +1,243 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * dir.c
+ */
+
+/*
+ * This file implements code to read directories from disk.
+ *
+ * See namei.c for a description of directory organisation on disk.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+static const unsigned char squashfs_filetype_table[] = {
+	DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_FIFO, DT_SOCK
+};
+
+/*
+ * Lookup offset (f_pos) in the directory index, returning the
+ * metadata block containing it.
+ *
+ * If we get an error reading the index then return the part of the index
+ * (if any) we have managed to read - the index isn't essential, just
+ * quicker.
+ */
+static int get_dir_index_using_offset(struct super_block *sb,
+	u64 *next_block, int *next_offset, u64 index_start, int index_offset,
+	int i_count, u64 f_pos)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int err, i, index, length = 0;
+	struct squashfs_dir_index dir_index;
+
+	TRACE("Entered get_dir_index_using_offset, i_count %d, f_pos %lld\n",
+					i_count, f_pos);
+
+	/*
+	 * Translate from external f_pos to the internal f_pos.  This
+	 * is offset by 3 because we invent "." and ".." entries which are
+	 * not actually stored in the directory.
+	 */
+	if (f_pos <= 3)
+		return f_pos;
+	f_pos -= 3;
+
+	for (i = 0; i < i_count; i++) {
+		err = squashfs_read_metadata(sb, &dir_index, &index_start,
+				&index_offset, sizeof(dir_index));
+		if (err < 0)
+			break;
+
+		index = le32_to_cpu(dir_index.index);
+		if (index > f_pos)
+			/*
+			 * Found the index we're looking for.
+			 */
+			break;
+
+		err = squashfs_read_metadata(sb, NULL, &index_start,
+				&index_offset, le32_to_cpu(dir_index.size) + 1);
+		if (err < 0)
+			break;
+
+		length = index;
+		*next_block = le32_to_cpu(dir_index.start_block) +
+					msblk->directory_table;
+	}
+
+	*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
+
+	/*
+	 * Translate back from internal f_pos to external f_pos.
+	 */
+	return length + 3;
+}
+
+
+static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
+{
+	struct inode *inode = file->f_dentry->d_inode;
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	u64 block = squashfs_i(inode)->start + msblk->directory_table;
+	int offset = squashfs_i(inode)->offset, length, dir_count, size,
+				type, err;
+	unsigned int inode_number;
+	struct squashfs_dir_header dirh;
+	struct squashfs_dir_entry *dire;
+
+	TRACE("Entered squashfs_readdir [%llx:%x]\n", block, offset);
+
+	dire = kmalloc(sizeof(*dire) + SQUASHFS_NAME_LEN + 1, GFP_KERNEL);
+	if (dire == NULL) {
+		ERROR("Failed to allocate squashfs_dir_entry\n");
+		goto finish;
+	}
+
+	/*
+	 * Return "." and  ".." entries as the first two filenames in the
+	 * directory.  To maximise compression these two entries are not
+	 * stored in the directory, and so we invent them here.
+	 *
+	 * It also means that the external f_pos is offset by 3 from the
+	 * on-disk directory f_pos.
+	 */
+	while (file->f_pos < 3) {
+		char *name;
+		int i_ino;
+
+		if (file->f_pos == 0) {
+			name = ".";
+			size = 1;
+			i_ino = inode->i_ino;
+		} else {
+			name = "..";
+			size = 2;
+			i_ino = squashfs_i(inode)->parent;
+		}
+
+		TRACE("Calling filldir(%p, %s, %d, %lld, %d, %d)\n",
+				dirent, name, size, 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(inode->i_sb, &block, &offset,
+				squashfs_i(inode)->dir_idx_start,
+				squashfs_i(inode)->dir_idx_offset,
+				squashfs_i(inode)->dir_idx_cnt,
+				file->f_pos);
+
+	while (length < i_size_read(inode)) {
+		/*
+		 * Read directory header
+		 */
+		err = squashfs_read_metadata(inode->i_sb, &dirh, &block,
+					&offset, sizeof(dirh));
+		if (err < 0)
+			goto failed_read;
+
+		length += sizeof(dirh);
+
+		dir_count = le32_to_cpu(dirh.count) + 1;
+
+		if (dir_count > SQUASHFS_DIR_COUNT)
+			goto failed_read;
+
+		while (dir_count--) {
+			/*
+			 * Read directory entry.
+			 */
+			err = squashfs_read_metadata(inode->i_sb, dire, &block,
+					&offset, sizeof(*dire));
+			if (err < 0)
+				goto failed_read;
+
+			size = le16_to_cpu(dire->size) + 1;
+
+			/* size should never be larger than SQUASHFS_NAME_LEN */
+			if (size > SQUASHFS_NAME_LEN)
+				goto failed_read;
+
+			err = squashfs_read_metadata(inode->i_sb, dire->name,
+					&block, &offset, size);
+			if (err < 0)
+				goto failed_read;
+
+			length += sizeof(*dire) + size;
+
+			if (file->f_pos >= length)
+				continue;
+
+			dire->name[size] = '\0';
+			inode_number = le32_to_cpu(dirh.inode_number) +
+				((short) le16_to_cpu(dire->inode_number));
+			type = le16_to_cpu(dire->type);
+
+			TRACE("Calling filldir(%p, %s, %d, %lld, %x:%x, %d, %d)"
+					"\n", dirent, dire->name, size,
+					file->f_pos,
+					le32_to_cpu(dirh.start_block),
+					le16_to_cpu(dire->offset),
+					inode_number,
+					squashfs_filetype_table[type]);
+
+			if (filldir(dirent, dire->name, size, file->f_pos,
+					inode_number,
+					squashfs_filetype_table[type]) < 0) {
+				TRACE("Filldir returned less than 0\n");
+				goto finish;
+			}
+
+			file->f_pos = length;
+		}
+	}
+
+finish:
+	kfree(dire);
+	return 0;
+
+failed_read:
+	ERROR("Unable to read directory block [%llx:%x]\n", block, offset);
+	kfree(dire);
+	return 0;
+}
+
+
+const struct file_operations squashfs_dir_ops = {
+	.read = generic_read_dir,
+	.readdir = squashfs_readdir,
+	.llseek = default_llseek,
+};

kernel/fs/squashfs/export.c

@@ -0,0 +1,163 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * export.c
+ */
+
+/*
+ * This file implements code to make Squashfs filesystems exportable (NFS etc.)
+ *
+ * The export code uses an inode lookup table to map inode numbers passed in
+ * filehandles to an inode location on disk.  This table is stored compressed
+ * into metadata blocks.  A second index table is used to locate these.  This
+ * second index table for speed of access (and because it is small) is read at
+ * mount time and cached in memory.
+ *
+ * The inode lookup table is used only by the export code, inode disk
+ * locations are directly encoded in directories, enabling direct access
+ * without an intermediate lookup for all operations except the export ops.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/dcache.h>
+#include <linux/exportfs.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+/*
+ * Look-up inode number (ino) in table, returning the inode location.
+ */
+static long long squashfs_inode_lookup(struct super_block *sb, int ino_num)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int blk = SQUASHFS_LOOKUP_BLOCK(ino_num - 1);
+	int offset = SQUASHFS_LOOKUP_BLOCK_OFFSET(ino_num - 1);
+	u64 start = le64_to_cpu(msblk->inode_lookup_table[blk]);
+	__le64 ino;
+	int err;
+
+	TRACE("Entered squashfs_inode_lookup, inode_number = %d\n", ino_num);
+
+	err = squashfs_read_metadata(sb, &ino, &start, &offset, sizeof(ino));
+	if (err < 0)
+		return err;
+
+	TRACE("squashfs_inode_lookup, inode = 0x%llx\n",
+		(u64) le64_to_cpu(ino));
+
+	return le64_to_cpu(ino);
+}
+
+
+static struct dentry *squashfs_export_iget(struct super_block *sb,
+	unsigned int ino_num)
+{
+	long long ino;
+	struct dentry *dentry = ERR_PTR(-ENOENT);
+
+	TRACE("Entered squashfs_export_iget\n");
+
+	ino = squashfs_inode_lookup(sb, ino_num);
+	if (ino >= 0)
+		dentry = d_obtain_alias(squashfs_iget(sb, ino, ino_num));
+
+	return dentry;
+}
+
+
+static struct dentry *squashfs_fh_to_dentry(struct super_block *sb,
+		struct fid *fid, int fh_len, int fh_type)
+{
+	if ((fh_type != FILEID_INO32_GEN && fh_type != FILEID_INO32_GEN_PARENT)
+			|| fh_len < 2)
+		return NULL;
+
+	return squashfs_export_iget(sb, fid->i32.ino);
+}
+
+
+static struct dentry *squashfs_fh_to_parent(struct super_block *sb,
+		struct fid *fid, int fh_len, int fh_type)
+{
+	if (fh_type != FILEID_INO32_GEN_PARENT || fh_len < 4)
+		return NULL;
+
+	return squashfs_export_iget(sb, fid->i32.parent_ino);
+}
+
+
+static struct dentry *squashfs_get_parent(struct dentry *child)
+{
+	struct inode *inode = child->d_inode;
+	unsigned int parent_ino = squashfs_i(inode)->parent;
+
+	return squashfs_export_iget(inode->i_sb, parent_ino);
+}
+
+
+/*
+ * Read uncompressed inode lookup table indexes off disk into memory
+ */
+__le64 *squashfs_read_inode_lookup_table(struct super_block *sb,
+		u64 lookup_table_start, u64 next_table, unsigned int inodes)
+{
+	unsigned int length = SQUASHFS_LOOKUP_BLOCK_BYTES(inodes);
+	__le64 *table;
+
+	TRACE("In read_inode_lookup_table, length %d\n", length);
+
+	/* Sanity check values */
+
+	/* there should always be at least one inode */
+	if (inodes == 0)
+		return ERR_PTR(-EINVAL);
+
+	/* length bytes should not extend into the next table - this check
+	 * also traps instances where lookup_table_start is incorrectly larger
+	 * than the next table start
+	 */
+	if (lookup_table_start + length > next_table)
+		return ERR_PTR(-EINVAL);
+
+	table = squashfs_read_table(sb, lookup_table_start, length);
+
+	/*
+	 * table[0] points to the first inode lookup table metadata block,
+	 * this should be less than lookup_table_start
+	 */
+	if (!IS_ERR(table) && le64_to_cpu(table[0]) >= lookup_table_start) {
+		kfree(table);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return table;
+}
+
+
+const struct export_operations squashfs_export_ops = {
+	.fh_to_dentry = squashfs_fh_to_dentry,
+	.fh_to_parent = squashfs_fh_to_parent,
+	.get_parent = squashfs_get_parent
+};

kernel/fs/squashfs/file.c

@@ -0,0 +1,501 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * file.c
+ */
+
+/*
+ * This file contains code for handling regular files.  A regular file
+ * consists of a sequence of contiguous compressed blocks, and/or a
+ * compressed fragment block (tail-end packed block).   The compressed size
+ * of each datablock is stored in a block list contained within the
+ * file inode (itself stored in one or more compressed metadata blocks).
+ *
+ * To speed up access to datablocks when reading 'large' files (256 Mbytes or
+ * larger), the code implements an index cache that caches the mapping from
+ * block index to datablock location on disk.
+ *
+ * The index cache allows Squashfs to handle large files (up to 1.75 TiB) while
+ * retaining a simple and space-efficient block list on disk.  The cache
+ * is split into slots, caching up to eight 224 GiB files (128 KiB blocks).
+ * Larger files use multiple slots, with 1.75 TiB files using all 8 slots.
+ * The index cache is designed to be memory efficient, and by default uses
+ * 16 KiB.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/pagemap.h>
+#include <linux/mutex.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+/*
+ * Locate cache slot in range [offset, index] for specified inode.  If
+ * there's more than one return the slot closest to index.
+ */
+static struct meta_index *locate_meta_index(struct inode *inode, int offset,
+				int index)
+{
+	struct meta_index *meta = NULL;
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	int i;
+
+	mutex_lock(&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_SLOTS; 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:
+	mutex_unlock(&msblk->meta_index_mutex);
+
+	return meta;
+}
+
+
+/*
+ * Find and initialise an empty cache slot for index offset.
+ */
+static struct meta_index *empty_meta_index(struct inode *inode, int offset,
+				int skip)
+{
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	struct meta_index *meta = NULL;
+	int i;
+
+	mutex_lock(&msblk->meta_index_mutex);
+
+	TRACE("empty_meta_index: offset %d, skip %d\n", offset, skip);
+
+	if (msblk->meta_index == NULL) {
+		/*
+		 * First time cache index has been used, allocate and
+		 * initialise.  The cache index could be allocated at
+		 * mount time but doing it here means it is allocated only
+		 * if a 'large' file is read.
+		 */
+		msblk->meta_index = kcalloc(SQUASHFS_META_SLOTS,
+			sizeof(*(msblk->meta_index)), GFP_KERNEL);
+		if (msblk->meta_index == NULL) {
+			ERROR("Failed to allocate meta_index\n");
+			goto failed;
+		}
+		for (i = 0; i < SQUASHFS_META_SLOTS; i++) {
+			msblk->meta_index[i].inode_number = 0;
+			msblk->meta_index[i].locked = 0;
+		}
+		msblk->next_meta_index = 0;
+	}
+
+	for (i = SQUASHFS_META_SLOTS; i &&
+			msblk->meta_index[msblk->next_meta_index].locked; i--)
+		msblk->next_meta_index = (msblk->next_meta_index + 1) %
+			SQUASHFS_META_SLOTS;
+
+	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_SLOTS;
+
+	meta->inode_number = inode->i_ino;
+	meta->offset = offset;
+	meta->skip = skip;
+	meta->entries = 0;
+	meta->locked = 1;
+
+failed:
+	mutex_unlock(&msblk->meta_index_mutex);
+	return meta;
+}
+
+
+static void release_meta_index(struct inode *inode, struct meta_index *meta)
+{
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	mutex_lock(&msblk->meta_index_mutex);
+	meta->locked = 0;
+	mutex_unlock(&msblk->meta_index_mutex);
+}
+
+
+/*
+ * Read the next n blocks from the block list, starting from
+ * metadata block <start_block, offset>.
+ */
+static long long read_indexes(struct super_block *sb, int n,
+				u64 *start_block, int *offset)
+{
+	int err, i;
+	long long block = 0;
+	__le32 *blist = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
+
+	if (blist == NULL) {
+		ERROR("read_indexes: Failed to allocate block_list\n");
+		return -ENOMEM;
+	}
+
+	while (n) {
+		int blocks = min_t(int, n, PAGE_CACHE_SIZE >> 2);
+
+		err = squashfs_read_metadata(sb, blist, start_block,
+				offset, blocks << 2);
+		if (err < 0) {
+			ERROR("read_indexes: reading block [%llx:%x]\n",
+				*start_block, *offset);
+			goto failure;
+		}
+
+		for (i = 0; i < blocks; i++) {
+			int size = le32_to_cpu(blist[i]);
+			block += SQUASHFS_COMPRESSED_SIZE_BLOCK(size);
+		}
+		n -= blocks;
+	}
+
+	kfree(blist);
+	return block;
+
+failure:
+	kfree(blist);
+	return err;
+}
+
+
+/*
+ * Each cache index slot has SQUASHFS_META_ENTRIES, each of which
+ * can cache one index -> datablock/blocklist-block mapping.  We wish
+ * to distribute these over the length of the file, entry[0] maps index x,
+ * entry[1] maps index x + skip, entry[2] maps index x + 2 * skip, and so on.
+ * The larger the file, the greater the skip factor.  The skip factor is
+ * limited to the size of the metadata cache (SQUASHFS_CACHED_BLKS) to ensure
+ * the number of metadata blocks that need to be read fits into the cache.
+ * If the skip factor is limited in this way then the file will use multiple
+ * slots.
+ */
+static inline int calculate_skip(int blocks)
+{
+	int skip = blocks / ((SQUASHFS_META_ENTRIES + 1)
+		 * SQUASHFS_META_INDEXES);
+	return min(SQUASHFS_CACHED_BLKS - 1, skip + 1);
+}
+
+
+/*
+ * Search and grow the index cache for the specified inode, returning the
+ * on-disk locations of the datablock and block list metadata block
+ * <index_block, index_offset> for index (scaled to nearest cache index).
+ */
+static int fill_meta_index(struct inode *inode, int index,
+		u64 *index_block, int *index_offset, u64 *data_block)
+{
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	int skip = calculate_skip(i_size_read(inode) >> msblk->block_log);
+	int offset = 0;
+	struct meta_index *meta;
+	struct meta_entry *meta_entry;
+	u64 cur_index_block = squashfs_i(inode)->block_list_start;
+	int cur_offset = squashfs_i(inode)->offset;
+	u64 cur_data_block = squashfs_i(inode)->start;
+	int err, i;
+
+	/*
+	 * Scale index to cache index (cache slot entry)
+	 */
+	index /= SQUASHFS_META_INDEXES * skip;
+
+	while (offset < index) {
+		meta = locate_meta_index(inode, offset + 1, index);
+
+		if (meta == NULL) {
+			meta = empty_meta_index(inode, offset + 1, skip);
+			if (meta == 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 +
+				msblk->inode_table;
+			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);
+		}
+
+		/*
+		 * If necessary grow cache slot by reading block list.  Cache
+		 * slot is extended up to index or to the end of the slot, in
+		 * which case further slots will be used.
+		 */
+		for (i = meta->offset + meta->entries; i <= index &&
+				i < meta->offset + SQUASHFS_META_ENTRIES; i++) {
+			int blocks = skip * SQUASHFS_META_INDEXES;
+			long long res = read_indexes(inode->i_sb, blocks,
+					&cur_index_block, &cur_offset);
+
+			if (res < 0) {
+				if (meta->entries == 0)
+					/*
+					 * Don't leave an empty slot on read
+					 * error allocated to this inode...
+					 */
+					meta->inode_number = 0;
+				err = res;
+				goto failed;
+			}
+
+			cur_data_block += res;
+			meta_entry = &meta->meta_entry[i - meta->offset];
+			meta_entry->index_block = cur_index_block -
+				msblk->inode_table;
+			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;
+
+	/*
+	 * Scale cache index (cache slot entry) to index
+	 */
+	return offset * SQUASHFS_META_INDEXES * skip;
+
+failed:
+	release_meta_index(inode, meta);
+	return err;
+}
+
+
+/*
+ * Get the on-disk location and compressed size of the datablock
+ * specified by index.  Fill_meta_index() does most of the work.
+ */
+static int read_blocklist(struct inode *inode, int index, u64 *block)
+{
+	u64 start;
+	long long blks;
+	int offset;
+	__le32 size;
+	int res = fill_meta_index(inode, index, &start, &offset, block);
+
+	TRACE("read_blocklist: res %d, index %d, start 0x%llx, offset"
+		       " 0x%x, block 0x%llx\n", res, index, start, offset,
+			*block);
+
+	if (res < 0)
+		return res;
+
+	/*
+	 * res contains the index of the mapping returned by fill_meta_index(),
+	 * this will likely be less than the desired index (because the
+	 * meta_index cache works at a higher granularity).  Read any
+	 * extra block indexes needed.
+	 */
+	if (res < index) {
+		blks = read_indexes(inode->i_sb, index - res, &start, &offset);
+		if (blks < 0)
+			return (int) blks;
+		*block += blks;
+	}
+
+	/*
+	 * Read length of block specified by index.
+	 */
+	res = squashfs_read_metadata(inode->i_sb, &size, &start, &offset,
+			sizeof(size));
+	if (res < 0)
+		return res;
+	return le32_to_cpu(size);
+}
+
+
+static int squashfs_readpage(struct file *file, struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	int bytes, i, offset = 0, sparse = 0;
+	struct squashfs_cache_entry *buffer = NULL;
+	void *pageaddr;
+
+	int mask = (1 << (msblk->block_log - PAGE_CACHE_SHIFT)) - 1;
+	int index = page->index >> (msblk->block_log - PAGE_CACHE_SHIFT);
+	int start_index = page->index & ~mask;
+	int end_index = start_index | mask;
+	int file_end = i_size_read(inode) >> msblk->block_log;
+
+	TRACE("Entered squashfs_readpage, page index %lx, start block %llx\n",
+				page->index, squashfs_i(inode)->start);
+
+	if (page->index >= ((i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+					PAGE_CACHE_SHIFT))
+		goto out;
+
+	if (index < file_end || squashfs_i(inode)->fragment_block ==
+					SQUASHFS_INVALID_BLK) {
+		/*
+		 * Reading a datablock from disk.  Need to read block list
+		 * to get location and block size.
+		 */
+		u64 block = 0;
+		int bsize = read_blocklist(inode, index, &block);
+		if (bsize < 0)
+			goto error_out;
+
+		if (bsize == 0) { /* hole */
+			bytes = index == file_end ?
+				(i_size_read(inode) & (msblk->block_size - 1)) :
+				 msblk->block_size;
+			sparse = 1;
+		} else {
+			/*
+			 * Read and decompress datablock.
+			 */
+			buffer = squashfs_get_datablock(inode->i_sb,
+								block, bsize);
+			if (buffer->error) {
+				ERROR("Unable to read page, block %llx, size %x"
+					"\n", block, bsize);
+				squashfs_cache_put(buffer);
+				goto error_out;
+			}
+			bytes = buffer->length;
+		}
+	} else {
+		/*
+		 * Datablock is stored inside a fragment (tail-end packed
+		 * block).
+		 */
+		buffer = squashfs_get_fragment(inode->i_sb,
+				squashfs_i(inode)->fragment_block,
+				squashfs_i(inode)->fragment_size);
+
+		if (buffer->error) {
+			ERROR("Unable to read page, block %llx, size %x\n",
+				squashfs_i(inode)->fragment_block,
+				squashfs_i(inode)->fragment_size);
+			squashfs_cache_put(buffer);
+			goto error_out;
+		}
+		bytes = i_size_read(inode) & (msblk->block_size - 1);
+		offset = squashfs_i(inode)->fragment_offset;
+	}
+
+	/*
+	 * Loop copying datablock into pages.  As the datablock likely covers
+	 * many PAGE_CACHE_SIZE pages (default block size is 128 KiB) explicitly
+	 * grab the pages from the page cache, except for the page that we've
+	 * been called to fill.
+	 */
+	for (i = start_index; i <= end_index && bytes > 0; i++,
+			bytes -= PAGE_CACHE_SIZE, offset += PAGE_CACHE_SIZE) {
+		struct page *push_page;
+		int avail = sparse ? 0 : min_t(int, bytes, PAGE_CACHE_SIZE);
+
+		TRACE("bytes %d, i %d, available_bytes %d\n", bytes, i, avail);
+
+		push_page = (i == page->index) ? page :
+			grab_cache_page_nowait(page->mapping, i);
+
+		if (!push_page)
+			continue;
+
+		if (PageUptodate(push_page))
+			goto skip_page;
+
+		pageaddr = kmap_atomic(push_page);
+		squashfs_copy_data(pageaddr, buffer, offset, avail);
+		memset(pageaddr + avail, 0, PAGE_CACHE_SIZE - avail);
+		kunmap_atomic(pageaddr);
+		flush_dcache_page(push_page);
+		SetPageUptodate(push_page);
+skip_page:
+		unlock_page(push_page);
+		if (i != page->index)
+			page_cache_release(push_page);
+	}
+
+	if (!sparse)
+		squashfs_cache_put(buffer);
+
+	return 0;
+
+error_out:
+	SetPageError(page);
+out:
+	pageaddr = kmap_atomic(page);
+	memset(pageaddr, 0, PAGE_CACHE_SIZE);
+	kunmap_atomic(pageaddr);
+	flush_dcache_page(page);
+	if (!PageError(page))
+		SetPageUptodate(page);
+	unlock_page(page);
+
+	return 0;
+}
+
+
+const struct address_space_operations squashfs_aops = {
+	.readpage = squashfs_readpage
+};

kernel/fs/squashfs/fragment.c

@@ -0,0 +1,99 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * fragment.c
+ */
+
+/*
+ * This file implements code to handle compressed fragments (tail-end packed
+ * datablocks).
+ *
+ * Regular files contain a fragment index which is mapped to a fragment
+ * location on disk and compressed size using a fragment lookup table.
+ * Like everything in Squashfs this fragment lookup table is itself stored
+ * compressed into metadata blocks.  A second index table is used to locate
+ * these.  This second index table for speed of access (and because it
+ * is small) is read at mount time and cached in memory.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+
+/*
+ * Look-up fragment using the fragment index table.  Return the on disk
+ * location of the fragment and its compressed size
+ */
+int squashfs_frag_lookup(struct super_block *sb, unsigned int fragment,
+				u64 *fragment_block)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int block = SQUASHFS_FRAGMENT_INDEX(fragment);
+	int offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
+	u64 start_block = le64_to_cpu(msblk->fragment_index[block]);
+	struct squashfs_fragment_entry fragment_entry;
+	int size;
+
+	size = squashfs_read_metadata(sb, &fragment_entry, &start_block,
+					&offset, sizeof(fragment_entry));
+	if (size < 0)
+		return size;
+
+	*fragment_block = le64_to_cpu(fragment_entry.start_block);
+	size = le32_to_cpu(fragment_entry.size);
+
+	return size;
+}
+
+
+/*
+ * Read the uncompressed fragment lookup table indexes off disk into memory
+ */
+__le64 *squashfs_read_fragment_index_table(struct super_block *sb,
+	u64 fragment_table_start, u64 next_table, unsigned int fragments)
+{
+	unsigned int length = SQUASHFS_FRAGMENT_INDEX_BYTES(fragments);
+	__le64 *table;
+
+	/*
+	 * Sanity check, length bytes should not extend into the next table -
+	 * this check also traps instances where fragment_table_start is
+	 * incorrectly larger than the next table start
+	 */
+	if (fragment_table_start + length > next_table)
+		return ERR_PTR(-EINVAL);
+
+	table = squashfs_read_table(sb, fragment_table_start, length);
+
+	/*
+	 * table[0] points to the first fragment table metadata block, this
+	 * should be less than fragment_table_start
+	 */
+	if (!IS_ERR(table) && le64_to_cpu(table[0]) >= fragment_table_start) {
+		kfree(table);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return table;
+}

kernel/fs/squashfs/id.c

@@ -0,0 +1,102 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * id.c
+ */
+
+/*
+ * This file implements code to handle uids and gids.
+ *
+ * For space efficiency regular files store uid and gid indexes, which are
+ * converted to 32-bit uids/gids using an id look up table.  This table is
+ * stored compressed into metadata blocks.  A second index table is used to
+ * locate these.  This second index table for speed of access (and because it
+ * is small) is read at mount time and cached in memory.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+
+/*
+ * Map uid/gid index into real 32-bit uid/gid using the id look up table
+ */
+int squashfs_get_id(struct super_block *sb, unsigned int index,
+					unsigned int *id)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int block = SQUASHFS_ID_BLOCK(index);
+	int offset = SQUASHFS_ID_BLOCK_OFFSET(index);
+	u64 start_block = le64_to_cpu(msblk->id_table[block]);
+	__le32 disk_id;
+	int err;
+
+	err = squashfs_read_metadata(sb, &disk_id, &start_block, &offset,
+							sizeof(disk_id));
+	if (err < 0)
+		return err;
+
+	*id = le32_to_cpu(disk_id);
+	return 0;
+}
+
+
+/*
+ * Read uncompressed id lookup table indexes from disk into memory
+ */
+__le64 *squashfs_read_id_index_table(struct super_block *sb,
+		u64 id_table_start, u64 next_table, unsigned short no_ids)
+{
+	unsigned int length = SQUASHFS_ID_BLOCK_BYTES(no_ids);
+	__le64 *table;
+
+	TRACE("In read_id_index_table, length %d\n", length);
+
+	/* Sanity check values */
+
+	/* there should always be at least one id */
+	if (no_ids == 0)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * length bytes should not extend into the next table - this check
+	 * also traps instances where id_table_start is incorrectly larger
+	 * than the next table start
+	 */
+	if (id_table_start + length > next_table)
+		return ERR_PTR(-EINVAL);
+
+	table = squashfs_read_table(sb, id_table_start, length);
+
+	/*
+	 * table[0] points to the first id lookup table metadata block, this
+	 * should be less than id_table_start
+	 */
+	if (!IS_ERR(table) && le64_to_cpu(table[0]) >= id_table_start) {
+		kfree(table);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return table;
+}

kernel/fs/squashfs/inode.c

@@ -0,0 +1,425 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * inode.c
+ */
+
+/*
+ * This file implements code to create and read inodes from disk.
+ *
+ * Inodes in Squashfs are identified by a 48-bit inode which encodes the
+ * location of the compressed metadata block containing the inode, and the byte
+ * offset into that block where the inode is placed (<block, offset>).
+ *
+ * To maximise compression there are different inodes for each file type
+ * (regular file, directory, device, etc.), the inode contents and length
+ * varying with the type.
+ *
+ * To further maximise compression, two types of regular file inode and
+ * directory inode are defined: inodes optimised for frequently occurring
+ * regular files and directories, and extended types where extra
+ * information has to be stored.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/xattr.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "xattr.h"
+
+/*
+ * Initialise VFS inode with the base inode information common to all
+ * Squashfs inode types.  Sqsh_ino contains the unswapped base inode
+ * off disk.
+ */
+static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
+				struct squashfs_base_inode *sqsh_ino)
+{
+	int err;
+
+	err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &inode->i_uid);
+	if (err)
+		return err;
+
+	err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &inode->i_gid);
+	if (err)
+		return err;
+
+	inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
+	inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
+	inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
+	inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
+	inode->i_mode = le16_to_cpu(sqsh_ino->mode);
+	inode->i_size = 0;
+
+	return err;
+}
+
+
+struct inode *squashfs_iget(struct super_block *sb, long long ino,
+				unsigned int ino_number)
+{
+	struct inode *inode = iget_locked(sb, ino_number);
+	int err;
+
+	TRACE("Entered squashfs_iget\n");
+
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	err = squashfs_read_inode(inode, ino);
+	if (err) {
+		iget_failed(inode);
+		return ERR_PTR(err);
+	}
+
+	unlock_new_inode(inode);
+	return inode;
+}
+
+
+/*
+ * Initialise VFS inode by reading inode from inode table (compressed
+ * metadata).  The format and amount of data read depends on type.
+ */
+int squashfs_read_inode(struct inode *inode, long long ino)
+{
+	struct super_block *sb = inode->i_sb;
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
+	int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
+	union squashfs_inode squashfs_ino;
+	struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
+	int xattr_id = SQUASHFS_INVALID_XATTR;
+
+	TRACE("Entered squashfs_read_inode\n");
+
+	/*
+	 * Read inode base common to all inode types.
+	 */
+	err = squashfs_read_metadata(sb, sqshb_ino, &block,
+				&offset, sizeof(*sqshb_ino));
+	if (err < 0)
+		goto failed_read;
+
+	err = squashfs_new_inode(sb, inode, sqshb_ino);
+	if (err)
+		goto failed_read;
+
+	block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
+	offset = SQUASHFS_INODE_OFFSET(ino);
+
+	type = le16_to_cpu(sqshb_ino->inode_type);
+	switch (type) {
+	case SQUASHFS_REG_TYPE: {
+		unsigned int frag_offset, frag;
+		int frag_size;
+		u64 frag_blk;
+		struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+							sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		frag = le32_to_cpu(sqsh_ino->fragment);
+		if (frag != SQUASHFS_INVALID_FRAG) {
+			frag_offset = le32_to_cpu(sqsh_ino->offset);
+			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
+			if (frag_size < 0) {
+				err = frag_size;
+				goto failed_read;
+			}
+		} else {
+			frag_blk = SQUASHFS_INVALID_BLK;
+			frag_size = 0;
+			frag_offset = 0;
+		}
+
+		set_nlink(inode, 1);
+		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
+		inode->i_fop = &generic_ro_fops;
+		inode->i_mode |= S_IFREG;
+		inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
+		squashfs_i(inode)->fragment_block = frag_blk;
+		squashfs_i(inode)->fragment_size = frag_size;
+		squashfs_i(inode)->fragment_offset = frag_offset;
+		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->block_list_start = block;
+		squashfs_i(inode)->offset = offset;
+		inode->i_data.a_ops = &squashfs_aops;
+
+		TRACE("File inode %x:%x, start_block %llx, block_list_start "
+			"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
+			offset, squashfs_i(inode)->start, block, offset);
+		break;
+	}
+	case SQUASHFS_LREG_TYPE: {
+		unsigned int frag_offset, frag;
+		int frag_size;
+		u64 frag_blk;
+		struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+							sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		frag = le32_to_cpu(sqsh_ino->fragment);
+		if (frag != SQUASHFS_INVALID_FRAG) {
+			frag_offset = le32_to_cpu(sqsh_ino->offset);
+			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
+			if (frag_size < 0) {
+				err = frag_size;
+				goto failed_read;
+			}
+		} else {
+			frag_blk = SQUASHFS_INVALID_BLK;
+			frag_size = 0;
+			frag_offset = 0;
+		}
+
+		xattr_id = le32_to_cpu(sqsh_ino->xattr);
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		inode->i_size = le64_to_cpu(sqsh_ino->file_size);
+		inode->i_op = &squashfs_inode_ops;
+		inode->i_fop = &generic_ro_fops;
+		inode->i_mode |= S_IFREG;
+		inode->i_blocks = (inode->i_size -
+				le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
+
+		squashfs_i(inode)->fragment_block = frag_blk;
+		squashfs_i(inode)->fragment_size = frag_size;
+		squashfs_i(inode)->fragment_offset = frag_offset;
+		squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->block_list_start = block;
+		squashfs_i(inode)->offset = offset;
+		inode->i_data.a_ops = &squashfs_aops;
+
+		TRACE("File inode %x:%x, start_block %llx, block_list_start "
+			"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
+			offset, squashfs_i(inode)->start, block, offset);
+		break;
+	}
+	case SQUASHFS_DIR_TYPE: {
+		struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		inode->i_size = le16_to_cpu(sqsh_ino->file_size);
+		inode->i_op = &squashfs_dir_inode_ops;
+		inode->i_fop = &squashfs_dir_ops;
+		inode->i_mode |= S_IFDIR;
+		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
+		squashfs_i(inode)->dir_idx_cnt = 0;
+		squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
+
+		TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
+				SQUASHFS_INODE_BLK(ino), offset,
+				squashfs_i(inode)->start,
+				le16_to_cpu(sqsh_ino->offset));
+		break;
+	}
+	case SQUASHFS_LDIR_TYPE: {
+		struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		xattr_id = le32_to_cpu(sqsh_ino->xattr);
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
+		inode->i_op = &squashfs_dir_inode_ops;
+		inode->i_fop = &squashfs_dir_ops;
+		inode->i_mode |= S_IFDIR;
+		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
+		squashfs_i(inode)->dir_idx_start = block;
+		squashfs_i(inode)->dir_idx_offset = offset;
+		squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
+		squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
+
+		TRACE("Long directory inode %x:%x, start_block %llx, offset "
+				"%x\n", SQUASHFS_INODE_BLK(ino), offset,
+				squashfs_i(inode)->start,
+				le16_to_cpu(sqsh_ino->offset));
+		break;
+	}
+	case SQUASHFS_SYMLINK_TYPE:
+	case SQUASHFS_LSYMLINK_TYPE: {
+		struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
+		inode->i_op = &squashfs_symlink_inode_ops;
+		inode->i_data.a_ops = &squashfs_symlink_aops;
+		inode->i_mode |= S_IFLNK;
+		squashfs_i(inode)->start = block;
+		squashfs_i(inode)->offset = offset;
+
+		if (type == SQUASHFS_LSYMLINK_TYPE) {
+			__le32 xattr;
+
+			err = squashfs_read_metadata(sb, NULL, &block,
+						&offset, inode->i_size);
+			if (err < 0)
+				goto failed_read;
+			err = squashfs_read_metadata(sb, &xattr, &block,
+						&offset, sizeof(xattr));
+			if (err < 0)
+				goto failed_read;
+			xattr_id = le32_to_cpu(xattr);
+		}
+
+		TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
+				"%x\n", SQUASHFS_INODE_BLK(ino), offset,
+				block, offset);
+		break;
+	}
+	case SQUASHFS_BLKDEV_TYPE:
+	case SQUASHFS_CHRDEV_TYPE: {
+		struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
+		unsigned int rdev;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		if (type == SQUASHFS_CHRDEV_TYPE)
+			inode->i_mode |= S_IFCHR;
+		else
+			inode->i_mode |= S_IFBLK;
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		rdev = le32_to_cpu(sqsh_ino->rdev);
+		init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
+
+		TRACE("Device inode %x:%x, rdev %x\n",
+				SQUASHFS_INODE_BLK(ino), offset, rdev);
+		break;
+	}
+	case SQUASHFS_LBLKDEV_TYPE:
+	case SQUASHFS_LCHRDEV_TYPE: {
+		struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
+		unsigned int rdev;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		if (type == SQUASHFS_LCHRDEV_TYPE)
+			inode->i_mode |= S_IFCHR;
+		else
+			inode->i_mode |= S_IFBLK;
+		xattr_id = le32_to_cpu(sqsh_ino->xattr);
+		inode->i_op = &squashfs_inode_ops;
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		rdev = le32_to_cpu(sqsh_ino->rdev);
+		init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
+
+		TRACE("Device inode %x:%x, rdev %x\n",
+				SQUASHFS_INODE_BLK(ino), offset, rdev);
+		break;
+	}
+	case SQUASHFS_FIFO_TYPE:
+	case SQUASHFS_SOCKET_TYPE: {
+		struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		if (type == SQUASHFS_FIFO_TYPE)
+			inode->i_mode |= S_IFIFO;
+		else
+			inode->i_mode |= S_IFSOCK;
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		init_special_inode(inode, inode->i_mode, 0);
+		break;
+	}
+	case SQUASHFS_LFIFO_TYPE:
+	case SQUASHFS_LSOCKET_TYPE: {
+		struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		if (type == SQUASHFS_LFIFO_TYPE)
+			inode->i_mode |= S_IFIFO;
+		else
+			inode->i_mode |= S_IFSOCK;
+		xattr_id = le32_to_cpu(sqsh_ino->xattr);
+		inode->i_op = &squashfs_inode_ops;
+		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
+		init_special_inode(inode, inode->i_mode, 0);
+		break;
+	}
+	default:
+		ERROR("Unknown inode type %d in squashfs_iget!\n", type);
+		return -EINVAL;
+	}
+
+	if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
+		err = squashfs_xattr_lookup(sb, xattr_id,
+					&squashfs_i(inode)->xattr_count,
+					&squashfs_i(inode)->xattr_size,
+					&squashfs_i(inode)->xattr);
+		if (err < 0)
+			goto failed_read;
+		inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
+				+ 1;
+	} else
+		squashfs_i(inode)->xattr_count = 0;
+
+	return 0;
+
+failed_read:
+	ERROR("Unable to read inode 0x%llx\n", ino);
+	return err;
+}
+
+
+const struct inode_operations squashfs_inode_ops = {
+	.getxattr = generic_getxattr,
+	.listxattr = squashfs_listxattr
+};
+

kernel/fs/squashfs/lzo_wrapper.c

@@ -0,0 +1,135 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2010 LG Electronics
+ * Chan Jeong <chan.jeong@lge.com>
+ *
+ * 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.
+ *
+ * lzo_wrapper.c
+ */
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/lzo.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+struct squashfs_lzo {
+	void	*input;
+	void	*output;
+};
+
+static void *lzo_init(struct squashfs_sb_info *msblk, void *buff, int len)
+{
+	int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
+
+	struct squashfs_lzo *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+	if (stream == NULL)
+		goto failed;
+	stream->input = vmalloc(block_size);
+	if (stream->input == NULL)
+		goto failed;
+	stream->output = vmalloc(block_size);
+	if (stream->output == NULL)
+		goto failed2;
+
+	return stream;
+
+failed2:
+	vfree(stream->input);
+failed:
+	ERROR("Failed to allocate lzo workspace\n");
+	kfree(stream);
+	return ERR_PTR(-ENOMEM);
+}
+
+
+static void lzo_free(void *strm)
+{
+	struct squashfs_lzo *stream = strm;
+
+	if (stream) {
+		vfree(stream->input);
+		vfree(stream->output);
+	}
+	kfree(stream);
+}
+
+
+static int lzo_uncompress(struct squashfs_sb_info *msblk, void **buffer,
+	struct buffer_head **bh, int b, int offset, int length, int srclength,
+	int pages)
+{
+	struct squashfs_lzo *stream = msblk->stream;
+	void *buff = stream->input;
+	int avail, i, bytes = length, res;
+	size_t out_len = srclength;
+
+	mutex_lock(&msblk->read_data_mutex);
+
+	for (i = 0; i < b; i++) {
+		wait_on_buffer(bh[i]);
+		if (!buffer_uptodate(bh[i]))
+			goto block_release;
+
+		avail = min(bytes, msblk->devblksize - offset);
+		memcpy(buff, bh[i]->b_data + offset, avail);
+		buff += avail;
+		bytes -= avail;
+		offset = 0;
+		put_bh(bh[i]);
+	}
+
+	res = lzo1x_decompress_safe(stream->input, (size_t)length,
+					stream->output, &out_len);
+	if (res != LZO_E_OK)
+		goto failed;
+
+	res = bytes = (int)out_len;
+	for (i = 0, buff = stream->output; bytes && i < pages; i++) {
+		avail = min_t(int, bytes, PAGE_CACHE_SIZE);
+		memcpy(buffer[i], buff, avail);
+		buff += avail;
+		bytes -= avail;
+	}
+
+	mutex_unlock(&msblk->read_data_mutex);
+	return res;
+
+block_release:
+	for (; i < b; i++)
+		put_bh(bh[i]);
+
+failed:
+	mutex_unlock(&msblk->read_data_mutex);
+
+	ERROR("lzo decompression failed, data probably corrupt\n");
+	return -EIO;
+}
+
+const struct squashfs_decompressor squashfs_lzo_comp_ops = {
+	.init = lzo_init,
+	.free = lzo_free,
+	.decompress = lzo_uncompress,
+	.id = LZO_COMPRESSION,
+	.name = "lzo",
+	.supported = 1
+};

kernel/fs/squashfs/namei.c

@@ -0,0 +1,248 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * namei.c
+ */
+
+/*
+ * This file implements code to do filename lookup in directories.
+ *
+ * Like inodes, directories are packed into compressed metadata blocks, stored
+ * in a directory table.  Directories are accessed using the start address of
+ * the metablock containing the directory and the offset into the
+ * decompressed block (<block, offset>).
+ *
+ * Directories are organised in a slightly complex way, and are not simply
+ * a list of file names.  The organisation takes advantage of the
+ * fact that (in most cases) the inodes of the files will be in the same
+ * compressed metadata block, and therefore, can share the start block.
+ * Directories are therefore organised in a two level list, a directory
+ * header containing the shared start block value, and a sequence of directory
+ * entries, each of which share the shared start block.  A new directory header
+ * is written once/if the inode start block changes.  The directory
+ * header/directory entry list is repeated as many times as necessary.
+ *
+ * Directories are sorted, and can contain a directory index to speed up
+ * file lookup.  Directory indexes store one entry per metablock, each entry
+ * storing the index/filename mapping to the first directory header
+ * in each metadata block.  Directories are sorted in alphabetical order,
+ * and at lookup the index is scanned linearly looking for the first filename
+ * alphabetically larger than the filename being looked up.  At this point the
+ * location of the metadata block the filename is in has been found.
+ * The general idea of the index is ensure only one metadata block needs to be
+ * decompressed to do a lookup irrespective of the length of the directory.
+ * This scheme has the advantage that it doesn't require extra memory overhead
+ * and doesn't require much extra storage on disk.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/dcache.h>
+#include <linux/xattr.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "xattr.h"
+
+/*
+ * Lookup name in the directory index, returning the location of the metadata
+ * block containing it, and the directory index this represents.
+ *
+ * If we get an error reading the index then return the part of the index
+ * (if any) we have managed to read - the index isn't essential, just
+ * quicker.
+ */
+static int get_dir_index_using_name(struct super_block *sb,
+			u64 *next_block, int *next_offset, u64 index_start,
+			int index_offset, int i_count, const char *name,
+			int len)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int i, size, length = 0, err;
+	struct squashfs_dir_index *index;
+	char *str;
+
+	TRACE("Entered get_dir_index_using_name, i_count %d\n", i_count);
+
+	index = kmalloc(sizeof(*index) + SQUASHFS_NAME_LEN * 2 + 2, GFP_KERNEL);
+	if (index == NULL) {
+		ERROR("Failed to allocate squashfs_dir_index\n");
+		goto out;
+	}
+
+	str = &index->name[SQUASHFS_NAME_LEN + 1];
+	strncpy(str, name, len);
+	str[len] = '\0';
+
+	for (i = 0; i < i_count; i++) {
+		err = squashfs_read_metadata(sb, index, &index_start,
+					&index_offset, sizeof(*index));
+		if (err < 0)
+			break;
+
+
+		size = le32_to_cpu(index->size) + 1;
+
+		err = squashfs_read_metadata(sb, index->name, &index_start,
+					&index_offset, size);
+		if (err < 0)
+			break;
+
+		index->name[size] = '\0';
+
+		if (strcmp(index->name, str) > 0)
+			break;
+
+		length = le32_to_cpu(index->index);
+		*next_block = le32_to_cpu(index->start_block) +
+					msblk->directory_table;
+	}
+
+	*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
+	kfree(index);
+
+out:
+	/*
+	 * Return index (f_pos) of the looked up metadata block.  Translate
+	 * from internal f_pos to external f_pos which is offset by 3 because
+	 * we invent "." and ".." entries which are not actually stored in the
+	 * directory.
+	 */
+	return length + 3;
+}
+
+
+static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
+				 struct nameidata *nd)
+{
+	const unsigned char *name = dentry->d_name.name;
+	int len = dentry->d_name.len;
+	struct inode *inode = NULL;
+	struct squashfs_sb_info *msblk = dir->i_sb->s_fs_info;
+	struct squashfs_dir_header dirh;
+	struct squashfs_dir_entry *dire;
+	u64 block = squashfs_i(dir)->start + msblk->directory_table;
+	int offset = squashfs_i(dir)->offset;
+	int err, length, dir_count, size;
+
+	TRACE("Entered squashfs_lookup [%llx:%x]\n", block, offset);
+
+	dire = kmalloc(sizeof(*dire) + SQUASHFS_NAME_LEN + 1, GFP_KERNEL);
+	if (dire == NULL) {
+		ERROR("Failed to allocate squashfs_dir_entry\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	if (len > SQUASHFS_NAME_LEN) {
+		err = -ENAMETOOLONG;
+		goto failed;
+	}
+
+	length = get_dir_index_using_name(dir->i_sb, &block, &offset,
+				squashfs_i(dir)->dir_idx_start,
+				squashfs_i(dir)->dir_idx_offset,
+				squashfs_i(dir)->dir_idx_cnt, name, len);
+
+	while (length < i_size_read(dir)) {
+		/*
+		 * Read directory header.
+		 */
+		err = squashfs_read_metadata(dir->i_sb, &dirh, &block,
+				&offset, sizeof(dirh));
+		if (err < 0)
+			goto read_failure;
+
+		length += sizeof(dirh);
+
+		dir_count = le32_to_cpu(dirh.count) + 1;
+
+		if (dir_count > SQUASHFS_DIR_COUNT)
+			goto data_error;
+
+		while (dir_count--) {
+			/*
+			 * Read directory entry.
+			 */
+			err = squashfs_read_metadata(dir->i_sb, dire, &block,
+					&offset, sizeof(*dire));
+			if (err < 0)
+				goto read_failure;
+
+			size = le16_to_cpu(dire->size) + 1;
+
+			/* size should never be larger than SQUASHFS_NAME_LEN */
+			if (size > SQUASHFS_NAME_LEN)
+				goto data_error;
+
+			err = squashfs_read_metadata(dir->i_sb, dire->name,
+					&block, &offset, size);
+			if (err < 0)
+				goto read_failure;
+
+			length += sizeof(*dire) + size;
+
+			if (name[0] < dire->name[0])
+				goto exit_lookup;
+
+			if (len == size && !strncmp(name, dire->name, len)) {
+				unsigned int blk, off, ino_num;
+				long long ino;
+				blk = le32_to_cpu(dirh.start_block);
+				off = le16_to_cpu(dire->offset);
+				ino_num = le32_to_cpu(dirh.inode_number) +
+					(short) le16_to_cpu(dire->inode_number);
+				ino = SQUASHFS_MKINODE(blk, off);
+
+				TRACE("calling squashfs_iget for directory "
+					"entry %s, inode  %x:%x, %d\n", name,
+					blk, off, ino_num);
+
+				inode = squashfs_iget(dir->i_sb, ino, ino_num);
+				goto exit_lookup;
+			}
+		}
+	}
+
+exit_lookup:
+	kfree(dire);
+	return d_splice_alias(inode, dentry);
+
+data_error:
+	err = -EIO;
+
+read_failure:
+	ERROR("Unable to read directory block [%llx:%x]\n",
+		squashfs_i(dir)->start + msblk->directory_table,
+		squashfs_i(dir)->offset);
+failed:
+	kfree(dire);
+	return ERR_PTR(err);
+}
+
+
+const struct inode_operations squashfs_dir_inode_ops = {
+	.lookup = squashfs_lookup,
+	.getxattr = generic_getxattr,
+	.listxattr = squashfs_listxattr
+};

kernel/fs/squashfs/squashfs.h

@@ -0,0 +1,99 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * squashfs.h
+ */
+
+#define TRACE(s, args...)	pr_debug("SQUASHFS: "s, ## args)
+
+#define ERROR(s, args...)	pr_err("SQUASHFS error: "s, ## args)
+
+#define WARNING(s, args...)	pr_warning("SQUASHFS: "s, ## args)
+
+/* block.c */
+extern int squashfs_read_data(struct super_block *, void **, u64, int, u64 *,
+				int, int);
+
+/* cache.c */
+extern struct squashfs_cache *squashfs_cache_init(char *, int, int);
+extern void squashfs_cache_delete(struct squashfs_cache *);
+extern struct squashfs_cache_entry *squashfs_cache_get(struct super_block *,
+				struct squashfs_cache *, u64, int);
+extern void squashfs_cache_put(struct squashfs_cache_entry *);
+extern int squashfs_copy_data(void *, struct squashfs_cache_entry *, int, int);
+extern int squashfs_read_metadata(struct super_block *, void *, u64 *,
+				int *, int);
+extern struct squashfs_cache_entry *squashfs_get_fragment(struct super_block *,
+				u64, int);
+extern struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *,
+				u64, int);
+extern void *squashfs_read_table(struct super_block *, u64, int);
+
+/* decompressor.c */
+extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
+extern void *squashfs_decompressor_init(struct super_block *, unsigned short);
+
+/* export.c */
+extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64, u64,
+				unsigned int);
+
+/* fragment.c */
+extern int squashfs_frag_lookup(struct super_block *, unsigned int, u64 *);
+extern __le64 *squashfs_read_fragment_index_table(struct super_block *,
+				u64, u64, unsigned int);
+
+/* id.c */
+extern int squashfs_get_id(struct super_block *, unsigned int, unsigned int *);
+extern __le64 *squashfs_read_id_index_table(struct super_block *, u64, u64,
+				unsigned short);
+
+/* inode.c */
+extern struct inode *squashfs_iget(struct super_block *, long long,
+				unsigned int);
+extern int squashfs_read_inode(struct inode *, long long);
+
+/* xattr.c */
+extern ssize_t squashfs_listxattr(struct dentry *, char *, size_t);
+
+/*
+ * Inodes, files,  decompressor and xattr operations
+ */
+
+/* dir.c */
+extern const struct file_operations squashfs_dir_ops;
+
+/* export.c */
+extern const struct export_operations squashfs_export_ops;
+
+/* file.c */
+extern const struct address_space_operations squashfs_aops;
+
+/* inode.c */
+extern const struct inode_operations squashfs_inode_ops;
+
+/* namei.c */
+extern const struct inode_operations squashfs_dir_inode_ops;
+
+/* symlink.c */
+extern const struct address_space_operations squashfs_symlink_aops;
+extern const struct inode_operations squashfs_symlink_inode_ops;
+
+/* xattr.c */
+extern const struct xattr_handler *squashfs_xattr_handlers[];

kernel/fs/squashfs/squashfs_fs.h

@@ -0,0 +1,453 @@
+#ifndef SQUASHFS_FS
+#define SQUASHFS_FS
+/*
+ * Squashfs
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * squashfs_fs.h
+ */
+
+#define SQUASHFS_CACHED_FRAGMENTS	CONFIG_SQUASHFS_FRAGMENT_CACHE_SIZE
+#define SQUASHFS_MAJOR			4
+#define SQUASHFS_MINOR			0
+#define SQUASHFS_START			0
+
+/* size of metadata (inode and directory) blocks */
+#define SQUASHFS_METADATA_SIZE		8192
+
+/* default size of block device I/O */
+#ifdef CONFIG_SQUASHFS_4K_DEVBLK_SIZE
+#define SQUASHFS_DEVBLK_SIZE 4096
+#else
+#define SQUASHFS_DEVBLK_SIZE 1024
+#endif
+
+#define SQUASHFS_FILE_MAX_SIZE		1048576
+#define SQUASHFS_FILE_MAX_LOG		20
+
+/* Max length of filename (not 255) */
+#define SQUASHFS_NAME_LEN		256
+
+/* Max value for directory header count*/
+#define SQUASHFS_DIR_COUNT		256
+
+#define SQUASHFS_INVALID_FRAG		(0xffffffffU)
+#define SQUASHFS_INVALID_XATTR		(0xffffffffU)
+#define SQUASHFS_INVALID_BLK		(-1LL)
+
+/* Filesystem flags */
+#define SQUASHFS_NOI			0
+#define SQUASHFS_NOD			1
+#define SQUASHFS_NOF			3
+#define SQUASHFS_NO_FRAG		4
+#define SQUASHFS_ALWAYS_FRAG		5
+#define SQUASHFS_DUPLICATE		6
+#define SQUASHFS_EXPORT			7
+#define SQUASHFS_COMP_OPT		10
+
+#define SQUASHFS_BIT(flag, bit)		((flag >> bit) & 1)
+
+#define SQUASHFS_UNCOMPRESSED_INODES(flags)	SQUASHFS_BIT(flags, \
+						SQUASHFS_NOI)
+
+#define SQUASHFS_UNCOMPRESSED_DATA(flags)	SQUASHFS_BIT(flags, \
+						SQUASHFS_NOD)
+
+#define SQUASHFS_UNCOMPRESSED_FRAGMENTS(flags)	SQUASHFS_BIT(flags, \
+						SQUASHFS_NOF)
+
+#define SQUASHFS_NO_FRAGMENTS(flags)		SQUASHFS_BIT(flags, \
+						SQUASHFS_NO_FRAG)
+
+#define SQUASHFS_ALWAYS_FRAGMENTS(flags)	SQUASHFS_BIT(flags, \
+						SQUASHFS_ALWAYS_FRAG)
+
+#define SQUASHFS_DUPLICATES(flags)		SQUASHFS_BIT(flags, \
+						SQUASHFS_DUPLICATE)
+
+#define SQUASHFS_EXPORTABLE(flags)		SQUASHFS_BIT(flags, \
+						SQUASHFS_EXPORT)
+
+#define SQUASHFS_COMP_OPTS(flags)		SQUASHFS_BIT(flags, \
+						SQUASHFS_COMP_OPT)
+
+/* Max number of types and file types */
+#define SQUASHFS_DIR_TYPE		1
+#define SQUASHFS_REG_TYPE		2
+#define SQUASHFS_SYMLINK_TYPE		3
+#define SQUASHFS_BLKDEV_TYPE		4
+#define SQUASHFS_CHRDEV_TYPE		5
+#define SQUASHFS_FIFO_TYPE		6
+#define SQUASHFS_SOCKET_TYPE		7
+#define SQUASHFS_LDIR_TYPE		8
+#define SQUASHFS_LREG_TYPE		9
+#define SQUASHFS_LSYMLINK_TYPE		10
+#define SQUASHFS_LBLKDEV_TYPE		11
+#define SQUASHFS_LCHRDEV_TYPE		12
+#define SQUASHFS_LFIFO_TYPE		13
+#define SQUASHFS_LSOCKET_TYPE		14
+
+/* Xattr types */
+#define SQUASHFS_XATTR_USER             0
+#define SQUASHFS_XATTR_TRUSTED          1
+#define SQUASHFS_XATTR_SECURITY         2
+#define SQUASHFS_XATTR_VALUE_OOL        256
+#define SQUASHFS_XATTR_PREFIX_MASK      0xff
+
+/* Flag whether block is compressed or uncompressed, bit is set if block is
+ * uncompressed */
+#define SQUASHFS_COMPRESSED_BIT		(1 << 15)
+
+#define SQUASHFS_COMPRESSED_SIZE(B)	(((B) & ~SQUASHFS_COMPRESSED_BIT) ? \
+		(B) & ~SQUASHFS_COMPRESSED_BIT :  SQUASHFS_COMPRESSED_BIT)
+
+#define SQUASHFS_COMPRESSED(B)		(!((B) & SQUASHFS_COMPRESSED_BIT))
+
+#define SQUASHFS_COMPRESSED_BIT_BLOCK	(1 << 24)
+
+#define SQUASHFS_COMPRESSED_SIZE_BLOCK(B)	((B) & \
+						~SQUASHFS_COMPRESSED_BIT_BLOCK)
+
+#define SQUASHFS_COMPRESSED_BLOCK(B)	(!((B) & SQUASHFS_COMPRESSED_BIT_BLOCK))
+
+/*
+ * Inode number ops.  Inodes consist of a compressed block number, and an
+ * uncompressed offset within that block
+ */
+#define SQUASHFS_INODE_BLK(A)		((unsigned int) ((A) >> 16))
+
+#define SQUASHFS_INODE_OFFSET(A)	((unsigned int) ((A) & 0xffff))
+
+#define SQUASHFS_MKINODE(A, B)		((long long)(((long long) (A)\
+					<< 16) + (B)))
+
+/* fragment and fragment table defines */
+#define SQUASHFS_FRAGMENT_BYTES(A)	\
+				((A) * sizeof(struct squashfs_fragment_entry))
+
+#define SQUASHFS_FRAGMENT_INDEX(A)	(SQUASHFS_FRAGMENT_BYTES(A) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_FRAGMENT_INDEX_OFFSET(A)	(SQUASHFS_FRAGMENT_BYTES(A) % \
+						SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_FRAGMENT_INDEXES(A)	((SQUASHFS_FRAGMENT_BYTES(A) + \
+					SQUASHFS_METADATA_SIZE - 1) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_FRAGMENT_INDEX_BYTES(A)	(SQUASHFS_FRAGMENT_INDEXES(A) *\
+						sizeof(u64))
+
+/* inode lookup table defines */
+#define SQUASHFS_LOOKUP_BYTES(A)	((A) * sizeof(u64))
+
+#define SQUASHFS_LOOKUP_BLOCK(A)	(SQUASHFS_LOOKUP_BYTES(A) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_LOOKUP_BLOCK_OFFSET(A)	(SQUASHFS_LOOKUP_BYTES(A) % \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_LOOKUP_BLOCKS(A)	((SQUASHFS_LOOKUP_BYTES(A) + \
+					SQUASHFS_METADATA_SIZE - 1) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_LOOKUP_BLOCK_BYTES(A)	(SQUASHFS_LOOKUP_BLOCKS(A) *\
+					sizeof(u64))
+
+/* uid/gid lookup table defines */
+#define SQUASHFS_ID_BYTES(A)		((A) * sizeof(unsigned int))
+
+#define SQUASHFS_ID_BLOCK(A)		(SQUASHFS_ID_BYTES(A) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_ID_BLOCK_OFFSET(A)	(SQUASHFS_ID_BYTES(A) % \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_ID_BLOCKS(A)		((SQUASHFS_ID_BYTES(A) + \
+					SQUASHFS_METADATA_SIZE - 1) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_ID_BLOCK_BYTES(A)	(SQUASHFS_ID_BLOCKS(A) *\
+					sizeof(u64))
+/* xattr id lookup table defines */
+#define SQUASHFS_XATTR_BYTES(A)		((A) * sizeof(struct squashfs_xattr_id))
+
+#define SQUASHFS_XATTR_BLOCK(A)		(SQUASHFS_XATTR_BYTES(A) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCK_OFFSET(A)	(SQUASHFS_XATTR_BYTES(A) % \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCKS(A)	((SQUASHFS_XATTR_BYTES(A) + \
+					SQUASHFS_METADATA_SIZE - 1) / \
+					SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCK_BYTES(A)	(SQUASHFS_XATTR_BLOCKS(A) *\
+					sizeof(u64))
+#define SQUASHFS_XATTR_BLK(A)		((unsigned int) ((A) >> 16))
+
+#define SQUASHFS_XATTR_OFFSET(A)	((unsigned int) ((A) & 0xffff))
+
+/* cached data constants for filesystem */
+#define SQUASHFS_CACHED_BLKS		8
+
+/* meta index cache */
+#define SQUASHFS_META_INDEXES	(SQUASHFS_METADATA_SIZE / sizeof(unsigned int))
+#define SQUASHFS_META_ENTRIES	127
+#define SQUASHFS_META_SLOTS	8
+
+struct meta_entry {
+	u64			data_block;
+	unsigned int		index_block;
+	unsigned short		offset;
+	unsigned short		pad;
+};
+
+struct meta_index {
+	unsigned int		inode_number;
+	unsigned int		offset;
+	unsigned short		entries;
+	unsigned short		skip;
+	unsigned short		locked;
+	unsigned short		pad;
+	struct meta_entry	meta_entry[SQUASHFS_META_ENTRIES];
+};
+
+
+/*
+ * definitions for structures on disk
+ */
+#define ZLIB_COMPRESSION	1
+#define LZMA_COMPRESSION	2
+#define LZO_COMPRESSION		3
+#define XZ_COMPRESSION		4
+
+struct squashfs_super_block {
+	__le32			s_magic;
+	__le32			inodes;
+	__le32			mkfs_time;
+	__le32			block_size;
+	__le32			fragments;
+	__le16			compression;
+	__le16			block_log;
+	__le16			flags;
+	__le16			no_ids;
+	__le16			s_major;
+	__le16			s_minor;
+	__le64			root_inode;
+	__le64			bytes_used;
+	__le64			id_table_start;
+	__le64			xattr_id_table_start;
+	__le64			inode_table_start;
+	__le64			directory_table_start;
+	__le64			fragment_table_start;
+	__le64			lookup_table_start;
+};
+
+struct squashfs_dir_index {
+	__le32			index;
+	__le32			start_block;
+	__le32			size;
+	unsigned char		name[0];
+};
+
+struct squashfs_base_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+};
+
+struct squashfs_ipc_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			nlink;
+};
+
+struct squashfs_lipc_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			nlink;
+	__le32			xattr;
+};
+
+struct squashfs_dev_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			nlink;
+	__le32			rdev;
+};
+
+struct squashfs_ldev_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			nlink;
+	__le32			rdev;
+	__le32			xattr;
+};
+
+struct squashfs_symlink_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			nlink;
+	__le32			symlink_size;
+	char			symlink[0];
+};
+
+struct squashfs_reg_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			start_block;
+	__le32			fragment;
+	__le32			offset;
+	__le32			file_size;
+	__le16			block_list[0];
+};
+
+struct squashfs_lreg_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le64			start_block;
+	__le64			file_size;
+	__le64			sparse;
+	__le32			nlink;
+	__le32			fragment;
+	__le32			offset;
+	__le32			xattr;
+	__le16			block_list[0];
+};
+
+struct squashfs_dir_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			start_block;
+	__le32			nlink;
+	__le16			file_size;
+	__le16			offset;
+	__le32			parent_inode;
+};
+
+struct squashfs_ldir_inode {
+	__le16			inode_type;
+	__le16			mode;
+	__le16			uid;
+	__le16			guid;
+	__le32			mtime;
+	__le32			inode_number;
+	__le32			nlink;
+	__le32			file_size;
+	__le32			start_block;
+	__le32			parent_inode;
+	__le16			i_count;
+	__le16			offset;
+	__le32			xattr;
+	struct squashfs_dir_index	index[0];
+};
+
+union squashfs_inode {
+	struct squashfs_base_inode		base;
+	struct squashfs_dev_inode		dev;
+	struct squashfs_ldev_inode		ldev;
+	struct squashfs_symlink_inode		symlink;
+	struct squashfs_reg_inode		reg;
+	struct squashfs_lreg_inode		lreg;
+	struct squashfs_dir_inode		dir;
+	struct squashfs_ldir_inode		ldir;
+	struct squashfs_ipc_inode		ipc;
+	struct squashfs_lipc_inode		lipc;
+};
+
+struct squashfs_dir_entry {
+	__le16			offset;
+	__le16			inode_number;
+	__le16			type;
+	__le16			size;
+	char			name[0];
+};
+
+struct squashfs_dir_header {
+	__le32			count;
+	__le32			start_block;
+	__le32			inode_number;
+};
+
+struct squashfs_fragment_entry {
+	__le64			start_block;
+	__le32			size;
+	unsigned int		unused;
+};
+
+struct squashfs_xattr_entry {
+	__le16			type;
+	__le16			size;
+	char			data[0];
+};
+
+struct squashfs_xattr_val {
+	__le32			vsize;
+	char			value[0];
+};
+
+struct squashfs_xattr_id {
+	__le64			xattr;
+	__le32			count;
+	__le32			size;
+};
+
+struct squashfs_xattr_id_table {
+	__le64			xattr_table_start;
+	__le32			xattr_ids;
+	__le32			unused;
+};
+
+#endif

kernel/fs/squashfs/squashfs_fs_i.h

@@ -0,0 +1,54 @@
+#ifndef SQUASHFS_FS_I
+#define SQUASHFS_FS_I
+/*
+ * Squashfs
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * squashfs_fs_i.h
+ */
+
+struct squashfs_inode_info {
+	u64		start;
+	int		offset;
+	u64		xattr;
+	unsigned int	xattr_size;
+	int		xattr_count;
+	union {
+		struct {
+			u64		fragment_block;
+			int		fragment_size;
+			int		fragment_offset;
+			u64		block_list_start;
+		};
+		struct {
+			u64		dir_idx_start;
+			int		dir_idx_offset;
+			int		dir_idx_cnt;
+			int		parent;
+		};
+	};
+	struct inode	vfs_inode;
+};
+
+
+static inline struct squashfs_inode_info *squashfs_i(struct inode *inode)
+{
+	return list_entry(inode, struct squashfs_inode_info, vfs_inode);
+}
+#endif

kernel/fs/squashfs/squashfs_fs_sb.h

@@ -0,0 +1,80 @@
+#ifndef SQUASHFS_FS_SB
+#define SQUASHFS_FS_SB
+/*
+ * Squashfs
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * squashfs_fs_sb.h
+ */
+
+#include "squashfs_fs.h"
+
+struct squashfs_cache {
+	char			*name;
+	int			entries;
+	int			curr_blk;
+	int			next_blk;
+	int			num_waiters;
+	int			unused;
+	int			block_size;
+	int			pages;
+	spinlock_t		lock;
+	wait_queue_head_t	wait_queue;
+	struct squashfs_cache_entry *entry;
+};
+
+struct squashfs_cache_entry {
+	u64			block;
+	int			length;
+	int			refcount;
+	u64			next_index;
+	int			pending;
+	int			error;
+	int			num_waiters;
+	wait_queue_head_t	wait_queue;
+	struct squashfs_cache	*cache;
+	void			**data;
+};
+
+struct squashfs_sb_info {
+	const struct squashfs_decompressor	*decompressor;
+	int					devblksize;
+	int					devblksize_log2;
+	struct squashfs_cache			*block_cache;
+	struct squashfs_cache			*fragment_cache;
+	struct squashfs_cache			*read_page;
+	int					next_meta_index;
+	__le64					*id_table;
+	__le64					*fragment_index;
+	__le64					*xattr_id_table;
+	struct mutex				read_data_mutex;
+	struct mutex				meta_index_mutex;
+	struct meta_index			*meta_index;
+	void					*stream;
+	__le64					*inode_lookup_table;
+	u64					inode_table;
+	u64					directory_table;
+	u64					xattr_table;
+	unsigned int				block_size;
+	unsigned short				block_log;
+	long long				bytes_used;
+	unsigned int				inodes;
+	int					xattr_ids;
+};
+#endif

kernel/fs/squashfs/super.c

@@ -0,0 +1,500 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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/magic.h>
+#include <linux/xattr.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "decompressor.h"
+#include "xattr.h"
+
+static struct file_system_type squashfs_fs_type;
+static const struct super_operations squashfs_super_ops;
+
+static const struct squashfs_decompressor *supported_squashfs_filesystem(short
+	major, short minor, short id)
+{
+	const struct squashfs_decompressor *decompressor;
+
+	if (major < SQUASHFS_MAJOR) {
+		ERROR("Major/Minor mismatch, older Squashfs %d.%d "
+			"filesystems are unsupported\n", major, minor);
+		return NULL;
+	} 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 NULL;
+	}
+
+	decompressor = squashfs_lookup_decompressor(id);
+	if (!decompressor->supported) {
+		ERROR("Filesystem uses \"%s\" compression. This is not "
+			"supported\n", decompressor->name);
+		return NULL;
+	}
+
+	return decompressor;
+}
+
+
+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, xattr_id_table_start, next_table;
+	int err;
+
+	TRACE("Entered squashfs_fill_superblock\n");
+
+	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
+	if (sb->s_fs_info == NULL) {
+		ERROR("Failed to allocate squashfs_sb_info\n");
+		return -ENOMEM;
+	}
+	msblk = sb->s_fs_info;
+
+	msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
+	msblk->devblksize_log2 = ffz(~msblk->devblksize);
+
+	mutex_init(&msblk->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);
+	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
+
+	if (IS_ERR(sblk)) {
+		ERROR("unable to read squashfs_super_block\n");
+		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 (!silent)
+			ERROR("Can't find a SQUASHFS superblock on %s\n",
+						bdevname(sb->s_bdev, b));
+		goto failed_mount;
+	}
+
+	/* Check the MAJOR & MINOR versions and lookup compression type */
+	msblk->decompressor = supported_squashfs_filesystem(
+			le16_to_cpu(sblk->s_major),
+			le16_to_cpu(sblk->s_minor),
+			le16_to_cpu(sblk->compression));
+	if (msblk->decompressor == NULL)
+		goto failed_mount;
+
+	/* Check the filesystem does not extend beyond the end of the
+	   block device */
+	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
+	if (msblk->bytes_used < 0 || msblk->bytes_used >
+			i_size_read(sb->s_bdev->bd_inode))
+		goto failed_mount;
+
+	/* Check block size for sanity */
+	msblk->block_size = le32_to_cpu(sblk->block_size);
+	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
+		goto failed_mount;
+
+	/*
+	 * Check the system page size is not larger than the filesystem
+	 * block size (by default 128K).  This is currently not supported.
+	 */
+	if (PAGE_CACHE_SIZE > msblk->block_size) {
+		ERROR("Page size > filesystem block size (%d).  This is "
+			"currently not supported!\n", 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 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;
+	}
+
+	msblk->stream = squashfs_decompressor_init(sb, flags);
+	if (IS_ERR(msblk->stream)) {
+		err = PTR_ERR(msblk->stream);
+		msblk->stream = NULL;
+		goto failed_mount;
+	}
+
+	/* 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)) {
+		ERROR("unable to read xattr id index table\n");
+		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,
+		le16_to_cpu(sblk->no_ids));
+	if (IS_ERR(msblk->id_table)) {
+		ERROR("unable to read id index table\n");
+		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)) {
+		ERROR("unable to read inode lookup table\n");
+		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 = le32_to_cpu(sblk->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)) {
+		ERROR("unable to read fragment index table\n");
+		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 failed_mount;
+	}
+
+	/* Sanity check inode_table */
+	if (msblk->inode_table >= msblk->directory_table) {
+		err = -EINVAL;
+		goto failed_mount;
+	}
+
+	/* 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;
+
+failed_mount:
+	squashfs_cache_delete(msblk->block_cache);
+	squashfs_cache_delete(msblk->fragment_cache);
+	squashfs_cache_delete(msblk->read_page);
+	squashfs_decompressor_free(msblk, msblk->stream);
+	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_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.val[0] = (u32)id;
+	buf->f_fsid.val[1] = (u32)(id >> 32);
+
+	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);
+		squashfs_decompressor_free(sbi, sbi->stream);
+		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 dentry *squashfs_mount(struct file_system_type *fs_type,
+				int flags, const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
+}
+
+
+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_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
+}
+
+static void squashfs_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, squashfs_i_callback);
+}
+
+
+static struct file_system_type squashfs_fs_type = {
+	.owner = THIS_MODULE,
+	.name = "squashfs",
+	.mount = squashfs_mount,
+	.kill_sb = kill_block_super,
+	.fs_flags = FS_REQUIRES_DEV
+};
+
+static const 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@squashfs.org.uk>");
+MODULE_LICENSE("GPL");

kernel/fs/squashfs/symlink.c

@@ -0,0 +1,127 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * symlink.c
+ */
+
+/*
+ * This file implements code to handle symbolic links.
+ *
+ * The data contents of symbolic links are stored inside the symbolic
+ * link inode within the inode table.  This allows the normally small symbolic
+ * link to be compressed as part of the inode table, achieving much greater
+ * compression than if the symbolic link was compressed individually.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/pagemap.h>
+#include <linux/xattr.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "xattr.h"
+
+static int squashfs_symlink_readpage(struct file *file, struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	struct super_block *sb = inode->i_sb;
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int index = page->index << PAGE_CACHE_SHIFT;
+	u64 block = squashfs_i(inode)->start;
+	int offset = squashfs_i(inode)->offset;
+	int length = min_t(int, i_size_read(inode) - index, PAGE_CACHE_SIZE);
+	int bytes, copied;
+	void *pageaddr;
+	struct squashfs_cache_entry *entry;
+
+	TRACE("Entered squashfs_symlink_readpage, page index %ld, start block "
+			"%llx, offset %x\n", page->index, block, offset);
+
+	/*
+	 * Skip index bytes into symlink metadata.
+	 */
+	if (index) {
+		bytes = squashfs_read_metadata(sb, NULL, &block, &offset,
+								index);
+		if (bytes < 0) {
+			ERROR("Unable to read symlink [%llx:%x]\n",
+				squashfs_i(inode)->start,
+				squashfs_i(inode)->offset);
+			goto error_out;
+		}
+	}
+
+	/*
+	 * Read length bytes from symlink metadata.  Squashfs_read_metadata
+	 * is not used here because it can sleep and we want to use
+	 * kmap_atomic to map the page.  Instead call the underlying
+	 * squashfs_cache_get routine.  As length bytes may overlap metadata
+	 * blocks, we may need to call squashfs_cache_get multiple times.
+	 */
+	for (bytes = 0; bytes < length; offset = 0, bytes += copied) {
+		entry = squashfs_cache_get(sb, msblk->block_cache, block, 0);
+		if (entry->error) {
+			ERROR("Unable to read symlink [%llx:%x]\n",
+				squashfs_i(inode)->start,
+				squashfs_i(inode)->offset);
+			squashfs_cache_put(entry);
+			goto error_out;
+		}
+
+		pageaddr = kmap_atomic(page);
+		copied = squashfs_copy_data(pageaddr + bytes, entry, offset,
+								length - bytes);
+		if (copied == length - bytes)
+			memset(pageaddr + length, 0, PAGE_CACHE_SIZE - length);
+		else
+			block = entry->next_index;
+		kunmap_atomic(pageaddr);
+		squashfs_cache_put(entry);
+	}
+
+	flush_dcache_page(page);
+	SetPageUptodate(page);
+	unlock_page(page);
+	return 0;
+
+error_out:
+	SetPageError(page);
+	unlock_page(page);
+	return 0;
+}
+
+
+const struct address_space_operations squashfs_symlink_aops = {
+	.readpage = squashfs_symlink_readpage
+};
+
+const struct inode_operations squashfs_symlink_inode_ops = {
+	.readlink = generic_readlink,
+	.follow_link = page_follow_link_light,
+	.put_link = page_put_link,
+	.getxattr = generic_getxattr,
+	.listxattr = squashfs_listxattr
+};
+

kernel/fs/squashfs/xattr.c

@@ -0,0 +1,324 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2010
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * xattr.c
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/xattr.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+static const struct xattr_handler *squashfs_xattr_handler(int);
+
+ssize_t squashfs_listxattr(struct dentry *d, char *buffer,
+	size_t buffer_size)
+{
+	struct inode *inode = d->d_inode;
+	struct super_block *sb = inode->i_sb;
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
+						 + msblk->xattr_table;
+	int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
+	int count = squashfs_i(inode)->xattr_count;
+	size_t rest = buffer_size;
+	int err;
+
+	/* check that the file system has xattrs */
+	if (msblk->xattr_id_table == NULL)
+		return -EOPNOTSUPP;
+
+	/* loop reading each xattr name */
+	while (count--) {
+		struct squashfs_xattr_entry entry;
+		struct squashfs_xattr_val val;
+		const struct xattr_handler *handler;
+		int name_size, prefix_size = 0;
+
+		err = squashfs_read_metadata(sb, &entry, &start, &offset,
+							sizeof(entry));
+		if (err < 0)
+			goto failed;
+
+		name_size = le16_to_cpu(entry.size);
+		handler = squashfs_xattr_handler(le16_to_cpu(entry.type));
+		if (handler)
+			prefix_size = handler->list(d, buffer, rest, NULL,
+				name_size, handler->flags);
+		if (prefix_size) {
+			if (buffer) {
+				if (prefix_size + name_size + 1 > rest) {
+					err = -ERANGE;
+					goto failed;
+				}
+				buffer += prefix_size;
+			}
+			err = squashfs_read_metadata(sb, buffer, &start,
+				&offset, name_size);
+			if (err < 0)
+				goto failed;
+			if (buffer) {
+				buffer[name_size] = '\0';
+				buffer += name_size + 1;
+			}
+			rest -= prefix_size + name_size + 1;
+		} else  {
+			/* no handler or insuffficient privileges, so skip */
+			err = squashfs_read_metadata(sb, NULL, &start,
+				&offset, name_size);
+			if (err < 0)
+				goto failed;
+		}
+
+
+		/* skip remaining xattr entry */
+		err = squashfs_read_metadata(sb, &val, &start, &offset,
+						sizeof(val));
+		if (err < 0)
+			goto failed;
+
+		err = squashfs_read_metadata(sb, NULL, &start, &offset,
+						le32_to_cpu(val.vsize));
+		if (err < 0)
+			goto failed;
+	}
+	err = buffer_size - rest;
+
+failed:
+	return err;
+}
+
+
+static int squashfs_xattr_get(struct inode *inode, int name_index,
+	const char *name, void *buffer, size_t buffer_size)
+{
+	struct super_block *sb = inode->i_sb;
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
+						 + msblk->xattr_table;
+	int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
+	int count = squashfs_i(inode)->xattr_count;
+	int name_len = strlen(name);
+	int err, vsize;
+	char *target = kmalloc(name_len, GFP_KERNEL);
+
+	if (target == NULL)
+		return  -ENOMEM;
+
+	/* loop reading each xattr name */
+	for (; count; count--) {
+		struct squashfs_xattr_entry entry;
+		struct squashfs_xattr_val val;
+		int type, prefix, name_size;
+
+		err = squashfs_read_metadata(sb, &entry, &start, &offset,
+							sizeof(entry));
+		if (err < 0)
+			goto failed;
+
+		name_size = le16_to_cpu(entry.size);
+		type = le16_to_cpu(entry.type);
+		prefix = type & SQUASHFS_XATTR_PREFIX_MASK;
+
+		if (prefix == name_index && name_size == name_len)
+			err = squashfs_read_metadata(sb, target, &start,
+						&offset, name_size);
+		else
+			err = squashfs_read_metadata(sb, NULL, &start,
+						&offset, name_size);
+		if (err < 0)
+			goto failed;
+
+		if (prefix == name_index && name_size == name_len &&
+					strncmp(target, name, name_size) == 0) {
+			/* found xattr */
+			if (type & SQUASHFS_XATTR_VALUE_OOL) {
+				__le64 xattr_val;
+				u64 xattr;
+				/* val is a reference to the real location */
+				err = squashfs_read_metadata(sb, &val, &start,
+						&offset, sizeof(val));
+				if (err < 0)
+					goto failed;
+				err = squashfs_read_metadata(sb, &xattr_val,
+					&start, &offset, sizeof(xattr_val));
+				if (err < 0)
+					goto failed;
+				xattr = le64_to_cpu(xattr_val);
+				start = SQUASHFS_XATTR_BLK(xattr) +
+							msblk->xattr_table;
+				offset = SQUASHFS_XATTR_OFFSET(xattr);
+			}
+			/* read xattr value */
+			err = squashfs_read_metadata(sb, &val, &start, &offset,
+							sizeof(val));
+			if (err < 0)
+				goto failed;
+
+			vsize = le32_to_cpu(val.vsize);
+			if (buffer) {
+				if (vsize > buffer_size) {
+					err = -ERANGE;
+					goto failed;
+				}
+				err = squashfs_read_metadata(sb, buffer, &start,
+					 &offset, vsize);
+				if (err < 0)
+					goto failed;
+			}
+			break;
+		}
+
+		/* no match, skip remaining xattr entry */
+		err = squashfs_read_metadata(sb, &val, &start, &offset,
+							sizeof(val));
+		if (err < 0)
+			goto failed;
+		err = squashfs_read_metadata(sb, NULL, &start, &offset,
+						le32_to_cpu(val.vsize));
+		if (err < 0)
+			goto failed;
+	}
+	err = count ? vsize : -ENODATA;
+
+failed:
+	kfree(target);
+	return err;
+}
+
+
+/*
+ * User namespace support
+ */
+static size_t squashfs_user_list(struct dentry *d, char *list, size_t list_size,
+	const char *name, size_t name_len, int type)
+{
+	if (list && XATTR_USER_PREFIX_LEN <= list_size)
+		memcpy(list, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
+	return XATTR_USER_PREFIX_LEN;
+}
+
+static int squashfs_user_get(struct dentry *d, const char *name, void *buffer,
+	size_t size, int type)
+{
+	if (name[0] == '\0')
+		return  -EINVAL;
+
+	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_USER, name,
+		buffer, size);
+}
+
+static const struct xattr_handler squashfs_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.list	= squashfs_user_list,
+	.get	= squashfs_user_get
+};
+
+/*
+ * Trusted namespace support
+ */
+static size_t squashfs_trusted_list(struct dentry *d, char *list,
+	size_t list_size, const char *name, size_t name_len, int type)
+{
+	if (!capable(CAP_SYS_ADMIN))
+		return 0;
+
+	if (list && XATTR_TRUSTED_PREFIX_LEN <= list_size)
+		memcpy(list, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
+	return XATTR_TRUSTED_PREFIX_LEN;
+}
+
+static int squashfs_trusted_get(struct dentry *d, const char *name,
+	void *buffer, size_t size, int type)
+{
+	if (name[0] == '\0')
+		return  -EINVAL;
+
+	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_TRUSTED, name,
+		buffer, size);
+}
+
+static const struct xattr_handler squashfs_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.list	= squashfs_trusted_list,
+	.get	= squashfs_trusted_get
+};
+
+/*
+ * Security namespace support
+ */
+static size_t squashfs_security_list(struct dentry *d, char *list,
+	size_t list_size, const char *name, size_t name_len, int type)
+{
+	if (list && XATTR_SECURITY_PREFIX_LEN <= list_size)
+		memcpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
+	return XATTR_SECURITY_PREFIX_LEN;
+}
+
+static int squashfs_security_get(struct dentry *d, const char *name,
+	void *buffer, size_t size, int type)
+{
+	if (name[0] == '\0')
+		return  -EINVAL;
+
+	return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_SECURITY, name,
+		buffer, size);
+}
+
+static const struct xattr_handler squashfs_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.list	= squashfs_security_list,
+	.get	= squashfs_security_get
+};
+
+static const struct xattr_handler *squashfs_xattr_handler(int type)
+{
+	if (type & ~(SQUASHFS_XATTR_PREFIX_MASK | SQUASHFS_XATTR_VALUE_OOL))
+		/* ignore unrecognised type */
+		return NULL;
+
+	switch (type & SQUASHFS_XATTR_PREFIX_MASK) {
+	case SQUASHFS_XATTR_USER:
+		return &squashfs_xattr_user_handler;
+	case SQUASHFS_XATTR_TRUSTED:
+		return &squashfs_xattr_trusted_handler;
+	case SQUASHFS_XATTR_SECURITY:
+		return &squashfs_xattr_security_handler;
+	default:
+		/* ignore unrecognised type */
+		return NULL;
+	}
+}
+
+const struct xattr_handler *squashfs_xattr_handlers[] = {
+	&squashfs_xattr_user_handler,
+	&squashfs_xattr_trusted_handler,
+	&squashfs_xattr_security_handler,
+	NULL
+};
+

kernel/fs/squashfs/xattr.h

@@ -0,0 +1,47 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2010
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * xattr.h
+ */
+
+#ifdef CONFIG_SQUASHFS_XATTR
+extern __le64 *squashfs_read_xattr_id_table(struct super_block *, u64,
+		u64 *, int *);
+extern int squashfs_xattr_lookup(struct super_block *, unsigned int, int *,
+		unsigned int *, unsigned long long *);
+#else
+static inline __le64 *squashfs_read_xattr_id_table(struct super_block *sb,
+		u64 start, u64 *xattr_table_start, int *xattr_ids)
+{
+	ERROR("Xattrs in filesystem, these will be ignored\n");
+	*xattr_table_start = start;
+	return ERR_PTR(-ENOTSUPP);
+}
+
+static inline int squashfs_xattr_lookup(struct super_block *sb,
+		unsigned int index, int *count, unsigned int *size,
+		unsigned long long *xattr)
+{
+	return 0;
+}
+#define squashfs_listxattr NULL
+#define generic_getxattr NULL
+#define squashfs_xattr_handlers NULL
+#endif

kernel/fs/squashfs/xattr_id.c

@@ -0,0 +1,95 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2010
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * xattr_id.c
+ */
+
+/*
+ * This file implements code to map the 32-bit xattr id stored in the inode
+ * into the on disk location of the xattr data.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "xattr.h"
+
+/*
+ * Map xattr id using the xattr id look up table
+ */
+int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
+		int *count, unsigned int *size, unsigned long long *xattr)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	int block = SQUASHFS_XATTR_BLOCK(index);
+	int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
+	u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
+	struct squashfs_xattr_id id;
+	int err;
+
+	err = squashfs_read_metadata(sb, &id, &start_block, &offset,
+							sizeof(id));
+	if (err < 0)
+		return err;
+
+	*xattr = le64_to_cpu(id.xattr);
+	*size = le32_to_cpu(id.size);
+	*count = le32_to_cpu(id.count);
+	return 0;
+}
+
+
+/*
+ * Read uncompressed xattr id lookup table indexes from disk into memory
+ */
+__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
+		u64 *xattr_table_start, int *xattr_ids)
+{
+	unsigned int len;
+	struct squashfs_xattr_id_table *id_table;
+
+	id_table = squashfs_read_table(sb, start, sizeof(*id_table));
+	if (IS_ERR(id_table))
+		return (__le64 *) id_table;
+
+	*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
+	*xattr_ids = le32_to_cpu(id_table->xattr_ids);
+	kfree(id_table);
+
+	/* Sanity check values */
+
+	/* there is always at least one xattr id */
+	if (*xattr_ids == 0)
+		return ERR_PTR(-EINVAL);
+
+	/* xattr_table should be less than start */
+	if (*xattr_table_start >= start)
+		return ERR_PTR(-EINVAL);
+
+	len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
+
+	TRACE("In read_xattr_index_table, length %d\n", len);
+
+	return squashfs_read_table(sb, start + sizeof(*id_table), len);
+}

kernel/fs/squashfs/xz_wrapper.c

@@ -0,0 +1,180 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * xz_wrapper.c
+ */
+
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/xz.h>
+#include <linux/bitops.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+struct squashfs_xz {
+	struct xz_dec *state;
+	struct xz_buf buf;
+};
+
+struct comp_opts {
+	__le32 dictionary_size;
+	__le32 flags;
+};
+
+static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff,
+	int len)
+{
+	struct comp_opts *comp_opts = buff;
+	struct squashfs_xz *stream;
+	int dict_size = msblk->block_size;
+	int err, n;
+
+	if (comp_opts) {
+		/* check compressor options are the expected length */
+		if (len < sizeof(*comp_opts)) {
+			err = -EIO;
+			goto failed;
+		}
+
+		dict_size = le32_to_cpu(comp_opts->dictionary_size);
+
+		/* the dictionary size should be 2^n or 2^n+2^(n+1) */
+		n = ffs(dict_size) - 1;
+		if (dict_size != (1 << n) && dict_size != (1 << n) +
+						(1 << (n + 1))) {
+			err = -EIO;
+			goto failed;
+		}
+	}
+
+	dict_size = max_t(int, dict_size, SQUASHFS_METADATA_SIZE);
+
+	stream = kmalloc(sizeof(*stream), GFP_KERNEL);
+	if (stream == NULL) {
+		err = -ENOMEM;
+		goto failed;
+	}
+
+	stream->state = xz_dec_init(XZ_PREALLOC, dict_size);
+	if (stream->state == NULL) {
+		kfree(stream);
+		err = -ENOMEM;
+		goto failed;
+	}
+
+	return stream;
+
+failed:
+	ERROR("Failed to initialise xz decompressor\n");
+	return ERR_PTR(err);
+}
+
+
+static void squashfs_xz_free(void *strm)
+{
+	struct squashfs_xz *stream = strm;
+
+	if (stream) {
+		xz_dec_end(stream->state);
+		kfree(stream);
+	}
+}
+
+
+static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer,
+	struct buffer_head **bh, int b, int offset, int length, int srclength,
+	int pages)
+{
+	enum xz_ret xz_err;
+	int avail, total = 0, k = 0, page = 0;
+	struct squashfs_xz *stream = msblk->stream;
+
+	mutex_lock(&msblk->read_data_mutex);
+
+	xz_dec_reset(stream->state);
+	stream->buf.in_pos = 0;
+	stream->buf.in_size = 0;
+	stream->buf.out_pos = 0;
+	stream->buf.out_size = PAGE_CACHE_SIZE;
+	stream->buf.out = buffer[page++];
+
+	do {
+		if (stream->buf.in_pos == stream->buf.in_size && k < b) {
+			avail = min(length, msblk->devblksize - offset);
+			length -= avail;
+			wait_on_buffer(bh[k]);
+			if (!buffer_uptodate(bh[k]))
+				goto release_mutex;
+
+			stream->buf.in = bh[k]->b_data + offset;
+			stream->buf.in_size = avail;
+			stream->buf.in_pos = 0;
+			offset = 0;
+		}
+
+		if (stream->buf.out_pos == stream->buf.out_size
+							&& page < pages) {
+			stream->buf.out = buffer[page++];
+			stream->buf.out_pos = 0;
+			total += PAGE_CACHE_SIZE;
+		}
+
+		xz_err = xz_dec_run(stream->state, &stream->buf);
+
+		if (stream->buf.in_pos == stream->buf.in_size && k < b)
+			put_bh(bh[k++]);
+	} while (xz_err == XZ_OK);
+
+	if (xz_err != XZ_STREAM_END) {
+		ERROR("xz_dec_run error, data probably corrupt\n");
+		goto release_mutex;
+	}
+
+	if (k < b) {
+		ERROR("xz_uncompress error, input remaining\n");
+		goto release_mutex;
+	}
+
+	total += stream->buf.out_pos;
+	mutex_unlock(&msblk->read_data_mutex);
+	return total;
+
+release_mutex:
+	mutex_unlock(&msblk->read_data_mutex);
+
+	for (; k < b; k++)
+		put_bh(bh[k]);
+
+	return -EIO;
+}
+
+const struct squashfs_decompressor squashfs_xz_comp_ops = {
+	.init = squashfs_xz_init,
+	.free = squashfs_xz_free,
+	.decompress = squashfs_xz_uncompress,
+	.id = XZ_COMPRESSION,
+	.name = "xz",
+	.supported = 1
+};

kernel/fs/squashfs/zlib_wrapper.c

@@ -0,0 +1,149 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@squashfs.org.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.
+ *
+ * zlib_wrapper.c
+ */
+
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/zlib.h>
+#include <linux/vmalloc.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+static void *zlib_init(struct squashfs_sb_info *dummy, void *buff, int len)
+{
+	z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
+	if (stream == NULL)
+		goto failed;
+	stream->workspace = vmalloc(zlib_inflate_workspacesize());
+	if (stream->workspace == NULL)
+		goto failed;
+
+	return stream;
+
+failed:
+	ERROR("Failed to allocate zlib workspace\n");
+	kfree(stream);
+	return ERR_PTR(-ENOMEM);
+}
+
+
+static void zlib_free(void *strm)
+{
+	z_stream *stream = strm;
+
+	if (stream)
+		vfree(stream->workspace);
+	kfree(stream);
+}
+
+
+static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
+	struct buffer_head **bh, int b, int offset, int length, int srclength,
+	int pages)
+{
+	int zlib_err, zlib_init = 0;
+	int k = 0, page = 0;
+	z_stream *stream = msblk->stream;
+
+	mutex_lock(&msblk->read_data_mutex);
+
+	stream->avail_out = 0;
+	stream->avail_in = 0;
+
+	do {
+		if (stream->avail_in == 0 && k < b) {
+			int avail = min(length, msblk->devblksize - offset);
+			length -= avail;
+			wait_on_buffer(bh[k]);
+			if (!buffer_uptodate(bh[k]))
+				goto release_mutex;
+
+			stream->next_in = bh[k]->b_data + offset;
+			stream->avail_in = avail;
+			offset = 0;
+		}
+
+		if (stream->avail_out == 0 && page < pages) {
+			stream->next_out = buffer[page++];
+			stream->avail_out = PAGE_CACHE_SIZE;
+		}
+
+		if (!zlib_init) {
+			zlib_err = zlib_inflateInit(stream);
+			if (zlib_err != Z_OK) {
+				ERROR("zlib_inflateInit returned unexpected "
+					"result 0x%x, srclength %d\n",
+					zlib_err, srclength);
+				goto release_mutex;
+			}
+			zlib_init = 1;
+		}
+
+		zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
+
+		if (stream->avail_in == 0 && k < b)
+			put_bh(bh[k++]);
+	} while (zlib_err == Z_OK);
+
+	if (zlib_err != Z_STREAM_END) {
+		ERROR("zlib_inflate error, data probably corrupt\n");
+		goto release_mutex;
+	}
+
+	zlib_err = zlib_inflateEnd(stream);
+	if (zlib_err != Z_OK) {
+		ERROR("zlib_inflate error, data probably corrupt\n");
+		goto release_mutex;
+	}
+
+	if (k < b) {
+		ERROR("zlib_uncompress error, data remaining\n");
+		goto release_mutex;
+	}
+
+	length = stream->total_out;
+	mutex_unlock(&msblk->read_data_mutex);
+	return length;
+
+release_mutex:
+	mutex_unlock(&msblk->read_data_mutex);
+
+	for (; k < b; k++)
+		put_bh(bh[k]);
+
+	return -EIO;
+}
+
+const struct squashfs_decompressor squashfs_zlib_comp_ops = {
+	.init = zlib_init,
+	.free = zlib_free,
+	.decompress = zlib_uncompress,
+	.id = ZLIB_COMPRESSION,
+	.name = "zlib",
+	.supported = 1
+};
+