Root/target/linux/generic/patches-2.6.36/006-squashfs_add_lzma.patch

1From f49e1efdd179d54e814ff2a8e8f469496583062c Mon Sep 17 00:00:00 2001
2From: Phillip Lougher <phillip@lougher.demon.co.uk>
3Date: Tue, 20 Oct 2009 10:54:36 +0100
4Subject: [PATCH] Squashfs: add LZMA compression
5
6Add support for LZMA compressed filesystems. This is an initial
7implementation.
8
9Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
10---
11 fs/squashfs/Kconfig | 5 ++
12 fs/squashfs/Makefile | 1 +
13 fs/squashfs/decompressor.c | 4 +
14 fs/squashfs/lzma_wrapper.c | 151 ++++++++++++++++++++++++++++++++++++++++++++
15 fs/squashfs/squashfs.h | 3 +
16 5 files changed, 164 insertions(+), 0 deletions(-)
17 create mode 100644 fs/squashfs/lzma_wrapper.c
18
19--- a/fs/squashfs/Kconfig
20+++ b/fs/squashfs/Kconfig
21@@ -37,6 +37,11 @@ config SQUASHFS_XATTRS
22 
23       If unsure, say N.
24 
25+config SQUASHFS_LZMA
26+ bool "Include support for LZMA compressed file systems"
27+ depends on SQUASHFS
28+ select DECOMPRESS_LZMA
29+
30 config SQUASHFS_EMBEDDED
31 
32     bool "Additional option for memory-constrained systems"
33--- a/fs/squashfs/Makefile
34+++ b/fs/squashfs/Makefile
35@@ -5,5 +5,5 @@
36 obj-$(CONFIG_SQUASHFS) += squashfs.o
37 squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
38 squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
39-squashfs-$(CONFIG_SQUASHFS_XATTRS) += xattr.o xattr_id.o
40+squashfs-$(CONFIG_SQUASHFS_LZMA) += lzma_wrapper.o
41 
42--- a/fs/squashfs/decompressor.c
43+++ b/fs/squashfs/decompressor.c
44@@ -50,7 +50,11 @@ static const struct squashfs_decompresso
45 
46 static const struct squashfs_decompressor *decompressor[] = {
47     &squashfs_zlib_comp_ops,
48+#ifdef CONFIG_SQUASHFS_LZMA
49+ &squashfs_lzma_comp_ops,
50+#else
51     &squashfs_lzma_unsupported_comp_ops,
52+#endif
53     &squashfs_lzo_unsupported_comp_ops,
54     &squashfs_unknown_comp_ops
55 };
56--- /dev/null
57+++ b/fs/squashfs/lzma_wrapper.c
58@@ -0,0 +1,152 @@
59+/*
60+ * Squashfs - a compressed read only filesystem for Linux
61+ *
62+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
63+ * Phillip Lougher <phillip@lougher.demon.co.uk>
64+ *
65+ * This program is free software; you can redistribute it and/or
66+ * modify it under the terms of the GNU General Public License
67+ * as published by the Free Software Foundation; either version 2,
68+ * or (at your option) any later version.
69+ *
70+ * This program is distributed in the hope that it will be useful,
71+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
72+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
73+ * GNU General Public License for more details.
74+ *
75+ * You should have received a copy of the GNU General Public License
76+ * along with this program; if not, write to the Free Software
77+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
78+ *
79+ * lzma_wrapper.c
80+ */
81+
82+#include <asm/unaligned.h>
83+#include <linux/buffer_head.h>
84+#include <linux/mutex.h>
85+#include <linux/vmalloc.h>
86+#include <linux/decompress/unlzma.h>
87+#include <linux/slab.h>
88+
89+#include "squashfs_fs.h"
90+#include "squashfs_fs_sb.h"
91+#include "squashfs_fs_i.h"
92+#include "squashfs.h"
93+#include "decompressor.h"
94+
95+struct squashfs_lzma {
96+ void *input;
97+ void *output;
98+};
99+
100+/* decompress_unlzma.c is currently non re-entrant... */
101+DEFINE_MUTEX(lzma_mutex);
102+
103+/* decompress_unlzma.c doesn't provide any context in its callbacks... */
104+static int lzma_error;
105+
106+static void error(char *m)
107+{
108+ ERROR("unlzma error: %s\n", m);
109+ lzma_error = 1;
110+}
111+
112+
113+static void *lzma_init(struct squashfs_sb_info *msblk)
114+{
115+ struct squashfs_lzma *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
116+ if (stream == NULL)
117+ goto failed;
118+ stream->input = vmalloc(msblk->block_size);
119+ if (stream->input == NULL)
120+ goto failed;
121+ stream->output = vmalloc(msblk->block_size);
122+ if (stream->output == NULL)
123+ goto failed2;
124+
125+ return stream;
126+
127+failed2:
128+ vfree(stream->input);
129+failed:
130+ ERROR("failed to allocate lzma workspace\n");
131+ kfree(stream);
132+ return NULL;
133+}
134+
135+
136+static void lzma_free(void *strm)
137+{
138+ struct squashfs_lzma *stream = strm;
139+
140+ if (stream) {
141+ vfree(stream->input);
142+ vfree(stream->output);
143+ }
144+ kfree(stream);
145+}
146+
147+
148+static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
149+ struct buffer_head **bh, int b, int offset, int length, int srclength,
150+ int pages)
151+{
152+ struct squashfs_lzma *stream = msblk->stream;
153+ void *buff = stream->input;
154+ int avail, i, bytes = length, res;
155+
156+ mutex_lock(&lzma_mutex);
157+
158+ for (i = 0; i < b; i++) {
159+ wait_on_buffer(bh[i]);
160+ if (!buffer_uptodate(bh[i]))
161+ goto block_release;
162+
163+ avail = min(bytes, msblk->devblksize - offset);
164+ memcpy(buff, bh[i]->b_data + offset, avail);
165+ buff += avail;
166+ bytes -= avail;
167+ offset = 0;
168+ put_bh(bh[i]);
169+ }
170+
171+ lzma_error = 0;
172+ res = unlzma(stream->input, length, NULL, NULL, stream->output, NULL,
173+ error);
174+ if (res || lzma_error)
175+ goto failed;
176+
177+ /* uncompressed size is stored in the LZMA header (5 byte offset) */
178+ res = bytes = get_unaligned_le32(stream->input + 5);
179+ for (i = 0, buff = stream->output; bytes && i < pages; i++) {
180+ avail = min_t(int, bytes, PAGE_CACHE_SIZE);
181+ memcpy(buffer[i], buff, avail);
182+ buff += avail;
183+ bytes -= avail;
184+ }
185+ if (bytes)
186+ goto failed;
187+
188+ mutex_unlock(&lzma_mutex);
189+ return res;
190+
191+block_release:
192+ for (; i < b; i++)
193+ put_bh(bh[i]);
194+
195+failed:
196+ mutex_unlock(&lzma_mutex);
197+
198+ ERROR("lzma decompression failed, data probably corrupt\n");
199+ return -EIO;
200+}
201+
202+const struct squashfs_decompressor squashfs_lzma_comp_ops = {
203+ .init = lzma_init,
204+ .free = lzma_free,
205+ .decompress = lzma_uncompress,
206+ .id = LZMA_COMPRESSION,
207+ .name = "lzma",
208+ .supported = 1
209+};
210+
211--- a/fs/squashfs/squashfs.h
212+++ b/fs/squashfs/squashfs.h
213@@ -104,3 +104,6 @@ extern const struct xattr_handler *squas
214 
215 /* zlib_wrapper.c */
216 extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
217+
218+/* lzma wrapper.c */
219+extern const struct squashfs_decompressor squashfs_lzma_comp_ops;
220

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