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426 lines
13 KiB
426 lines
13 KiB
From 327fbf47a419befc6bff74f3ca42d2b6f0841903 Mon Sep 17 00:00:00 2001
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From: Phillip Lougher <phillip@lougher.demon.co.uk>
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Date: Tue, 6 Oct 2009 04:04:15 +0100
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Subject: [PATCH] Squashfs: add a decompressor framework
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This adds a decompressor framework which allows multiple compression
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algorithms to be cleanly supported.
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Also update zlib wrapper and other code to use the new framework.
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Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
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---
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fs/squashfs/Makefile | 2 +-
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fs/squashfs/block.c | 6 ++--
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fs/squashfs/decompressor.c | 58 ++++++++++++++++++++++++++++++++++++++++++
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fs/squashfs/decompressor.h | 55 +++++++++++++++++++++++++++++++++++++++
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fs/squashfs/squashfs.h | 14 +++++-----
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fs/squashfs/squashfs_fs_sb.h | 41 +++++++++++++++--------------
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fs/squashfs/super.c | 45 ++++++++++++++++++-------------
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fs/squashfs/zlib_wrapper.c | 17 ++++++++++--
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8 files changed, 185 insertions(+), 53 deletions(-)
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create mode 100644 fs/squashfs/decompressor.c
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create mode 100644 fs/squashfs/decompressor.h
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--- a/fs/squashfs/Makefile
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+++ b/fs/squashfs/Makefile
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@@ -4,4 +4,4 @@
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obj-$(CONFIG_SQUASHFS) += squashfs.o
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squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
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-squashfs-y += namei.o super.o symlink.o zlib_wrapper.o
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+squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
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--- a/fs/squashfs/block.c
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+++ b/fs/squashfs/block.c
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@@ -36,7 +36,7 @@
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#include "squashfs_fs_sb.h"
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#include "squashfs_fs_i.h"
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#include "squashfs.h"
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-
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+#include "decompressor.h"
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/*
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* Read the metadata block length, this is stored in the first two
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* bytes of the metadata block.
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@@ -151,8 +151,8 @@ int squashfs_read_data(struct super_bloc
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}
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if (compressed) {
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- length = zlib_uncompress(msblk, buffer, bh, b, offset, length,
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- srclength, pages);
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+ length = squashfs_decompress(msblk, buffer, bh, b, offset,
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+ length, srclength, pages);
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if (length < 0)
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goto read_failure;
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} else {
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--- /dev/null
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+++ b/fs/squashfs/decompressor.c
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@@ -0,0 +1,58 @@
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+/*
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+ * Squashfs - a compressed read only filesystem for Linux
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+ *
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+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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+ * Phillip Lougher <phillip@lougher.demon.co.uk>
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License
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+ * as published by the Free Software Foundation; either version 2,
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+ * or (at your option) any later version.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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+ *
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+ * decompressor.c
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+ */
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+
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+#include <linux/types.h>
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+#include <linux/mutex.h>
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+#include <linux/buffer_head.h>
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+
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+#include "squashfs_fs.h"
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+#include "squashfs_fs_sb.h"
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+#include "squashfs_fs_i.h"
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+#include "decompressor.h"
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+#include "squashfs.h"
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+
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+/*
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+ * This file (and decompressor.h) implements a decompressor framework for
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+ * Squashfs, allowing multiple decompressors to be easily supported
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+ */
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+
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+static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
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+ NULL, NULL, NULL, 0, "unknown", 0
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+};
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+
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+static const struct squashfs_decompressor *decompressor[] = {
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+ &squashfs_zlib_comp_ops,
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+ &squashfs_unknown_comp_ops
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+};
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+
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+
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+const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
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+{
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+ int i;
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+
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+ for (i = 0; decompressor[i]->id; i++)
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+ if (id == decompressor[i]->id)
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+ break;
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+
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+ return decompressor[i];
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+}
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--- /dev/null
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+++ b/fs/squashfs/decompressor.h
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@@ -0,0 +1,55 @@
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+#ifndef DECOMPRESSOR_H
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+#define DECOMPRESSOR_H
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+/*
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+ * Squashfs - a compressed read only filesystem for Linux
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+ *
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+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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+ * Phillip Lougher <phillip@lougher.demon.co.uk>
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License
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+ * as published by the Free Software Foundation; either version 2,
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+ * or (at your option) any later version.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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+ *
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+ * decompressor.h
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+ */
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+
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+struct squashfs_decompressor {
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+ void *(*init)(void);
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+ void (*free)(void *);
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+ int (*decompress)(struct squashfs_sb_info *, void **,
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+ struct buffer_head **, int, int, int, int, int);
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+ int id;
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+ char *name;
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+ int supported;
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+};
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+
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+static inline void *squashfs_decompressor_init(struct squashfs_sb_info *msblk)
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+{
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+ return msblk->decompressor->init();
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+}
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+
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+static inline void squashfs_decompressor_free(struct squashfs_sb_info *msblk,
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+ void *s)
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+{
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+ if (msblk->decompressor)
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+ msblk->decompressor->free(s);
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+}
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+
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+static inline int squashfs_decompress(struct squashfs_sb_info *msblk,
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+ void **buffer, struct buffer_head **bh, int b, int offset, int length,
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+ int srclength, int pages)
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+{
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+ return msblk->decompressor->decompress(msblk, buffer, bh, b, offset,
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+ length, srclength, pages);
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+}
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+#endif
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--- a/fs/squashfs/squashfs.h
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+++ b/fs/squashfs/squashfs.h
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@@ -51,6 +51,9 @@ extern struct squashfs_cache_entry *squa
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u64, int);
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extern int squashfs_read_table(struct super_block *, void *, u64, int);
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+/* decompressor.c */
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+extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
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+
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/* export.c */
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extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,
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unsigned int);
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@@ -70,14 +73,8 @@ extern struct inode *squashfs_iget(struc
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unsigned int);
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extern int squashfs_read_inode(struct inode *, long long);
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-/* zlib_wrapper.c */
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-extern void *zlib_init(void);
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-extern void zlib_free(void *);
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-extern int zlib_uncompress(struct squashfs_sb_info *, void **,
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- struct buffer_head **, int, int, int, int, int);
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-
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/*
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- * Inodes and files operations
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+ * Inodes, files and decompressor operations
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*/
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/* dir.c */
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@@ -94,3 +91,6 @@ extern const struct inode_operations squ
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/* symlink.c */
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extern const struct address_space_operations squashfs_symlink_aops;
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+
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+/* zlib_wrapper.c */
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+extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
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--- a/fs/squashfs/squashfs_fs_sb.h
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+++ b/fs/squashfs/squashfs_fs_sb.h
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@@ -52,25 +52,26 @@ struct squashfs_cache_entry {
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};
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struct squashfs_sb_info {
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- int devblksize;
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- int devblksize_log2;
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- struct squashfs_cache *block_cache;
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- struct squashfs_cache *fragment_cache;
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- struct squashfs_cache *read_page;
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- int next_meta_index;
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- __le64 *id_table;
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- __le64 *fragment_index;
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- unsigned int *fragment_index_2;
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- struct mutex read_data_mutex;
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- struct mutex meta_index_mutex;
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- struct meta_index *meta_index;
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- void *stream;
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- __le64 *inode_lookup_table;
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- u64 inode_table;
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- u64 directory_table;
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- unsigned int block_size;
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- unsigned short block_log;
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- long long bytes_used;
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- unsigned int inodes;
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+ const struct squashfs_decompressor *decompressor;
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+ int devblksize;
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+ int devblksize_log2;
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+ struct squashfs_cache *block_cache;
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+ struct squashfs_cache *fragment_cache;
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+ struct squashfs_cache *read_page;
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+ int next_meta_index;
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+ __le64 *id_table;
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+ __le64 *fragment_index;
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+ unsigned int *fragment_index_2;
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+ struct mutex read_data_mutex;
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+ struct mutex meta_index_mutex;
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+ struct meta_index *meta_index;
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+ void *stream;
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+ __le64 *inode_lookup_table;
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+ u64 inode_table;
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+ u64 directory_table;
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+ unsigned int block_size;
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+ unsigned short block_log;
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+ long long bytes_used;
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+ unsigned int inodes;
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};
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#endif
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--- a/fs/squashfs/super.c
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+++ b/fs/squashfs/super.c
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@@ -41,27 +41,35 @@
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#include "squashfs_fs_sb.h"
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#include "squashfs_fs_i.h"
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#include "squashfs.h"
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+#include "decompressor.h"
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static struct file_system_type squashfs_fs_type;
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static struct super_operations squashfs_super_ops;
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-static int supported_squashfs_filesystem(short major, short minor, short comp)
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+static const struct squashfs_decompressor *supported_squashfs_filesystem(short
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+ major, short minor, short id)
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{
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+ const struct squashfs_decompressor *decompressor;
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+
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if (major < SQUASHFS_MAJOR) {
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ERROR("Major/Minor mismatch, older Squashfs %d.%d "
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"filesystems are unsupported\n", major, minor);
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- return -EINVAL;
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+ return NULL;
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} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
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ERROR("Major/Minor mismatch, trying to mount newer "
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"%d.%d filesystem\n", major, minor);
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ERROR("Please update your kernel\n");
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- return -EINVAL;
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+ return NULL;
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}
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- if (comp != ZLIB_COMPRESSION)
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- return -EINVAL;
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+ decompressor = squashfs_lookup_decompressor(id);
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+ if (!decompressor->supported) {
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+ ERROR("Filesystem uses \"%s\" compression. This is not "
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+ "supported\n", decompressor->name);
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+ return NULL;
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+ }
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- return 0;
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+ return decompressor;
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}
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@@ -86,10 +94,6 @@ static int squashfs_fill_super(struct su
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}
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msblk = sb->s_fs_info;
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- msblk->stream = zlib_init();
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- if (msblk->stream == NULL)
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- goto failure;
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-
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sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
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if (sblk == NULL) {
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ERROR("Failed to allocate squashfs_super_block\n");
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@@ -116,25 +120,25 @@ static int squashfs_fill_super(struct su
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goto failed_mount;
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}
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+ err = -EINVAL;
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+
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/* Check it is a SQUASHFS superblock */
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sb->s_magic = le32_to_cpu(sblk->s_magic);
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if (sb->s_magic != SQUASHFS_MAGIC) {
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if (!silent)
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ERROR("Can't find a SQUASHFS superblock on %s\n",
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bdevname(sb->s_bdev, b));
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- err = -EINVAL;
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goto failed_mount;
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}
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- /* Check the MAJOR & MINOR versions and compression type */
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- err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
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+ /* Check the MAJOR & MINOR versions and lookup compression type */
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+ msblk->decompressor = supported_squashfs_filesystem(
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+ le16_to_cpu(sblk->s_major),
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le16_to_cpu(sblk->s_minor),
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le16_to_cpu(sblk->compression));
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- if (err < 0)
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+ if (msblk->decompressor == NULL)
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goto failed_mount;
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- err = -EINVAL;
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-
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/*
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* Check if there's xattrs in the filesystem. These are not
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* supported in this version, so warn that they will be ignored.
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@@ -201,6 +205,10 @@ static int squashfs_fill_super(struct su
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err = -ENOMEM;
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+ msblk->stream = squashfs_decompressor_init(msblk);
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+ if (msblk->stream == NULL)
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+ goto failed_mount;
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+
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msblk->block_cache = squashfs_cache_init("metadata",
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SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
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if (msblk->block_cache == NULL)
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@@ -288,7 +296,7 @@ failed_mount:
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squashfs_cache_delete(msblk->block_cache);
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squashfs_cache_delete(msblk->fragment_cache);
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squashfs_cache_delete(msblk->read_page);
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- zlib_free(msblk->stream);
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+ squashfs_decompressor_free(msblk, msblk->stream);
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kfree(msblk->inode_lookup_table);
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kfree(msblk->fragment_index);
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kfree(msblk->id_table);
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@@ -298,7 +306,6 @@ failed_mount:
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return err;
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failure:
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- zlib_free(msblk->stream);
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kfree(sb->s_fs_info);
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sb->s_fs_info = NULL;
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return -ENOMEM;
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@@ -342,7 +349,7 @@ static void squashfs_put_super(struct su
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squashfs_cache_delete(sbi->block_cache);
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squashfs_cache_delete(sbi->fragment_cache);
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squashfs_cache_delete(sbi->read_page);
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- zlib_free(sbi->stream);
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+ squashfs_decompressor_free(sbi, sbi->stream);
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kfree(sbi->id_table);
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kfree(sbi->fragment_index);
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kfree(sbi->meta_index);
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--- a/fs/squashfs/zlib_wrapper.c
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+++ b/fs/squashfs/zlib_wrapper.c
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@@ -30,8 +30,9 @@
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#include "squashfs_fs_sb.h"
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#include "squashfs_fs_i.h"
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#include "squashfs.h"
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+#include "decompressor.h"
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-void *zlib_init()
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+static void *zlib_init(void)
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{
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z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
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if (stream == NULL)
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@@ -50,7 +51,7 @@ failed:
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}
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-void zlib_free(void *strm)
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+static void zlib_free(void *strm)
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{
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z_stream *stream = strm;
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@@ -60,7 +61,7 @@ void zlib_free(void *strm)
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}
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-int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
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+static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
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struct buffer_head **bh, int b, int offset, int length, int srclength,
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int pages)
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{
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@@ -137,3 +138,13 @@ release_mutex:
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return -EIO;
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}
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+
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+const struct squashfs_decompressor squashfs_zlib_comp_ops = {
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+ .init = zlib_init,
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+ .free = zlib_free,
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+ .decompress = zlib_uncompress,
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+ .id = ZLIB_COMPRESSION,
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+ .name = "zlib",
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+ .supported = 1
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+};
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+
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