Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus:
  Squashfs: get rid of obsolete definition in header file
  Squashfs: get rid of obsolete variable in struct squashfs_sb_info
  Squashfs: add decompressor entries for lzma and lzo
  Squashfs: add a decompressor framework
  Squashfs: factor out remaining zlib dependencies into separate wrapper file
  Squashfs: move zlib decompression wrapper code into a separate file

18 files changed, 335 insertions, 128 deletions

diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index 70e3244fa30f..df8a19ef870d 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -4,4 +4,4 @@
 
 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
+squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 2a7960310349..1cb0d81b164b 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -29,15 +29,14 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
-#include <linux/mutex.h>
 #include <linux/string.h>
 #include <linux/buffer_head.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
 #include "squashfs_fs_i.h"
 #include "squashfs.h"
+#include "decompressor.h"
 
 /*
  * Read the metadata block length, this is stored in the first two
@@ -153,72 +152,10 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 	}
 
 	if (compressed) {
-		int zlib_err = 0, zlib_init = 0;
-
-		/*
-		 * Uncompress block.
-		 */
-
-		mutex_lock(&msblk->read_data_mutex);
-
-		msblk->stream.avail_out = 0;
-		msblk->stream.avail_in = 0;
-
-		bytes = length;
-		do {
-			if (msblk->stream.avail_in == 0 && k < b) {
-				avail = min(bytes, msblk->devblksize - offset);
-				bytes -= avail;
-				wait_on_buffer(bh[k]);
-				if (!buffer_uptodate(bh[k]))
-					goto release_mutex;
-
-				if (avail == 0) {
-					offset = 0;
-					put_bh(bh[k++]);
-					continue;
-				}
-
-				msblk->stream.next_in = bh[k]->b_data + offset;
-				msblk->stream.avail_in = avail;
-				offset = 0;
-			}
-
-			if (msblk->stream.avail_out == 0 && page < pages) {
-				msblk->stream.next_out = buffer[page++];
-				msblk->stream.avail_out = PAGE_CACHE_SIZE;
-			}
-
-			if (!zlib_init) {
-				zlib_err = zlib_inflateInit(&msblk->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(&msblk->stream, Z_SYNC_FLUSH);
-
-			if (msblk->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(&msblk->stream);
-		if (zlib_err != Z_OK) {
-			ERROR("zlib_inflate error, data probably corrupt\n");
-			goto release_mutex;
-		}
-		length = msblk->stream.total_out;
-		mutex_unlock(&msblk->read_data_mutex);
+		length = squashfs_decompress(msblk, buffer, bh, b, offset,
+			 length, srclength, pages);
+		if (length < 0)
+			goto read_failure;
 	} else {
 		/*
 		 * Block is uncompressed.
@@ -255,9 +192,6 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 	kfree(bh);
 	return length;
 
-release_mutex:
-	mutex_unlock(&msblk->read_data_mutex);
-
 block_release:
 	for (; k < b; k++)
 		put_bh(bh[k]);
diff --git a/fs/squashfs/cache.c b/fs/squashfs/cache.c
index 40c98fa6b5d6..57314bee9059 100644
--- a/fs/squashfs/cache.c
+++ b/fs/squashfs/cache.c
@@ -51,7 +51,6 @@
 #include <linux/sched.h>
 #include <linux/spinlock.h>
 #include <linux/wait.h>
-#include <linux/zlib.h>
 #include <linux/pagemap.h>
 
 #include "squashfs_fs.h"
diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
new file mode 100644
index 000000000000..157478da6ac9
--- /dev/null
+++ b/fs/squashfs/decompressor.c
@@ -0,0 +1,68 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@lougher.demon.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * decompressor.c
+ */
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.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
+};
+
+static const struct squashfs_decompressor squashfs_lzo_unsupported_comp_ops = {
+	NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
+};
+
+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_lzma_unsupported_comp_ops,
+	&squashfs_lzo_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];
+}
diff --git a/fs/squashfs/decompressor.h b/fs/squashfs/decompressor.h
new file mode 100644
index 000000000000..7425f80783f6
--- /dev/null
+++ b/fs/squashfs/decompressor.h
@@ -0,0 +1,55 @@
+#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@lougher.demon.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * decompressor.h
+ */
+
+struct squashfs_decompressor {
+	void	*(*init)(struct squashfs_sb_info *);
+	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_init(struct squashfs_sb_info *msblk)
+{
+	return msblk->decompressor->init(msblk);
+}
+
+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);
+}
+#endif
diff --git a/fs/squashfs/dir.c b/fs/squashfs/dir.c
index 566b0eaed868..12b933ac6585 100644
--- a/fs/squashfs/dir.c
+++ b/fs/squashfs/dir.c
@@ -30,7 +30,6 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
diff --git a/fs/squashfs/export.c b/fs/squashfs/export.c
index 2b1b8fe5e037..7f93d5a9ee05 100644
--- a/fs/squashfs/export.c
+++ b/fs/squashfs/export.c
@@ -39,7 +39,6 @@
 #include <linux/vfs.h>
 #include <linux/dcache.h>
 #include <linux/exportfs.h>
-#include <linux/zlib.h>
 #include <linux/slab.h>
 
 #include "squashfs_fs.h"
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index 717767d831df..a25c5060bdcb 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -47,7 +47,6 @@
 #include <linux/string.h>
 #include <linux/pagemap.h>
 #include <linux/mutex.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
diff --git a/fs/squashfs/fragment.c b/fs/squashfs/fragment.c
index b5a2c15bbbc7..7c90bbd6879d 100644
--- a/fs/squashfs/fragment.c
+++ b/fs/squashfs/fragment.c
@@ -36,7 +36,6 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
diff --git a/fs/squashfs/id.c b/fs/squashfs/id.c
index 3795b837ba28..b7f64bcd2b70 100644
--- a/fs/squashfs/id.c
+++ b/fs/squashfs/id.c
@@ -34,7 +34,6 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
diff --git a/fs/squashfs/inode.c b/fs/squashfs/inode.c
index 9101dbde39ec..49daaf669e41 100644
--- a/fs/squashfs/inode.c
+++ b/fs/squashfs/inode.c
@@ -40,7 +40,6 @@
 
 #include <linux/fs.h>
 #include <linux/vfs.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
diff --git a/fs/squashfs/namei.c b/fs/squashfs/namei.c
index 9e398653b22b..5266bd8ad932 100644
--- a/fs/squashfs/namei.c
+++ b/fs/squashfs/namei.c
@@ -57,7 +57,6 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/dcache.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index 0e9feb6adf7e..fe2587af5512 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -51,6 +51,9 @@ extern struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *,
 				u64, int);
 extern int squashfs_read_table(struct super_block *, void *, u64, int);
 
+/* decompressor.c */
+extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
+
 /* export.c */
 extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,
 				unsigned int);
@@ -71,7 +74,7 @@ extern struct inode *squashfs_iget(struct super_block *, long long,
 extern int squashfs_read_inode(struct inode *, long long);
 
 /*
- * Inodes and files operations
+ * Inodes, files and decompressor operations
  */
 
 /* dir.c */
@@ -88,3 +91,6 @@ extern const struct inode_operations squashfs_dir_inode_ops;
 
 /* symlink.c */
 extern const struct address_space_operations squashfs_symlink_aops;
+
+/* zlib_wrapper.c */
+extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
diff --git a/fs/squashfs/squashfs_fs.h b/fs/squashfs/squashfs_fs.h
index 283daafc568e..79024245ea00 100644
--- a/fs/squashfs/squashfs_fs.h
+++ b/fs/squashfs/squashfs_fs.h
@@ -183,8 +183,6 @@
 #define SQUASHFS_MAX_FILE_SIZE		(1LL << \
 					(SQUASHFS_MAX_FILE_SIZE_LOG - 2))
 
-#define SQUASHFS_MARKER_BYTE		0xff
-
 /* meta index cache */
 #define SQUASHFS_META_INDEXES	(SQUASHFS_METADATA_SIZE / sizeof(unsigned int))
 #define SQUASHFS_META_ENTRIES	127
@@ -211,7 +209,9 @@ struct meta_index {
 /*
  * definitions for structures on disk
  */
-#define ZLIB_COMPRESSION	 1
+#define ZLIB_COMPRESSION	1
+#define LZMA_COMPRESSION	2
+#define LZO_COMPRESSION		3
 
 struct squashfs_super_block {
 	__le32			s_magic;
diff --git a/fs/squashfs/squashfs_fs_sb.h b/fs/squashfs/squashfs_fs_sb.h
index c8c65614dd1c..2e77dc547e25 100644
--- a/fs/squashfs/squashfs_fs_sb.h
+++ b/fs/squashfs/squashfs_fs_sb.h
@@ -52,25 +52,25 @@ struct squashfs_cache_entry {
 };
 
 struct squashfs_sb_info {
-	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;
-	unsigned int		*fragment_index_2;
-	struct mutex		read_data_mutex;
-	struct mutex		meta_index_mutex;
-	struct meta_index	*meta_index;
-	z_stream		stream;
-	__le64			*inode_lookup_table;
-	u64			inode_table;
-	u64			directory_table;
-	unsigned int		block_size;
-	unsigned short		block_log;
-	long long		bytes_used;
-	unsigned int		inodes;
+	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;
+	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;
+	unsigned int				block_size;
+	unsigned short				block_log;
+	long long				bytes_used;
+	unsigned int				inodes;
 };
 #endif
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 6c197ef53add..3550aec2f655 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -35,34 +35,41 @@
 #include <linux/pagemap.h>
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/zlib.h>
 #include <linux/magic.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
 #include "squashfs_fs_i.h"
 #include "squashfs.h"
+#include "decompressor.h"
 
 static struct file_system_type squashfs_fs_type;
 static const struct super_operations squashfs_super_ops;
 
-static int supported_squashfs_filesystem(short major, short minor, short comp)
+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 -EINVAL;
+		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 -EINVAL;
+		return NULL;
 	}
 
-	if (comp != ZLIB_COMPRESSION)
-		return -EINVAL;
+	decompressor = squashfs_lookup_decompressor(id);
+	if (!decompressor->supported) {
+		ERROR("Filesystem uses \"%s\" compression. This is not "
+			"supported\n", decompressor->name);
+		return NULL;
+	}
 
-	return 0;
+	return decompressor;
 }
 
 
@@ -87,13 +94,6 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 	msblk = sb->s_fs_info;
 
-	msblk->stream.workspace = kmalloc(zlib_inflate_workspacesize(),
-		GFP_KERNEL);
-	if (msblk->stream.workspace == NULL) {
-		ERROR("Failed to allocate zlib workspace\n");
-		goto failure;
-	}
-
 	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
 	if (sblk == NULL) {
 		ERROR("Failed to allocate squashfs_super_block\n");
@@ -120,25 +120,25 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 		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));
-		err = -EINVAL;
 		goto failed_mount;
 	}
 
-	/* Check the MAJOR & MINOR versions and compression type */
-	err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
+	/* 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 (err < 0)
+	if (msblk->decompressor == NULL)
 		goto failed_mount;
 
-	err = -EINVAL;
-
 	/*
 	 * Check if there's xattrs in the filesystem.  These are not
 	 * supported in this version, so warn that they will be ignored.
@@ -205,6 +205,10 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	err = -ENOMEM;
 
+	msblk->stream = squashfs_decompressor_init(msblk);
+	if (msblk->stream == NULL)
+		goto failed_mount;
+
 	msblk->block_cache = squashfs_cache_init("metadata",
 			SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
 	if (msblk->block_cache == NULL)
@@ -292,17 +296,16 @@ 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->stream.workspace);
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
 	kfree(sblk);
 	return err;
 
 failure:
-	kfree(msblk->stream.workspace);
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
 	return -ENOMEM;
@@ -346,10 +349,10 @@ static void squashfs_put_super(struct super_block *sb)
 		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->stream.workspace);
 		kfree(sb->s_fs_info);
 		sb->s_fs_info = NULL;
 	}
diff --git a/fs/squashfs/symlink.c b/fs/squashfs/symlink.c
index 83d87880aac8..e80be2022a7f 100644
--- a/fs/squashfs/symlink.c
+++ b/fs/squashfs/symlink.c
@@ -36,7 +36,6 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/pagemap.h>
-#include <linux/zlib.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
diff --git a/fs/squashfs/zlib_wrapper.c b/fs/squashfs/zlib_wrapper.c
new file mode 100644
index 000000000000..4dd70e04333b
--- /dev/null
+++ b/fs/squashfs/zlib_wrapper.c
@@ -0,0 +1,150 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@lougher.demon.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * zlib_wrapper.c
+ */
+
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/zlib.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+static void *zlib_init(struct squashfs_sb_info *dummy)
+{
+	z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
+	if (stream == NULL)
+		goto failed;
+	stream->workspace = kmalloc(zlib_inflate_workspacesize(),
+		GFP_KERNEL);
+	if (stream->workspace == NULL)
+		goto failed;
+
+	return stream;
+
+failed:
+	ERROR("Failed to allocate zlib workspace\n");
+	kfree(stream);
+	return NULL;
+}
+
+
+static void zlib_free(void *strm)
+{
+	z_stream *stream = strm;
+
+	if (stream)
+		kfree(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 = 0, zlib_init = 0;
+	int avail, bytes, k = 0, page = 0;
+	z_stream *stream = msblk->stream;
+
+	mutex_lock(&msblk->read_data_mutex);
+
+	stream->avail_out = 0;
+	stream->avail_in = 0;
+
+	bytes = length;
+	do {
+		if (stream->avail_in == 0 && k < b) {
+			avail = min(bytes, msblk->devblksize - offset);
+			bytes -= avail;
+			wait_on_buffer(bh[k]);
+			if (!buffer_uptodate(bh[k]))
+				goto release_mutex;
+
+			if (avail == 0) {
+				offset = 0;
+				put_bh(bh[k++]);
+				continue;
+			}
+
+			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;
+	}
+
+	mutex_unlock(&msblk->read_data_mutex);
+	return stream->total_out;
+
+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
+};
+