Root/target/linux/generic-2.6/patches-2.6.30/006-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@@ -26,6 +26,11 @@ config SQUASHFS
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@@ -5,3 +5,4 @@
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_LZMA) += lzma_wrapper.o
40--- a/fs/squashfs/decompressor.c
41+++ b/fs/squashfs/decompressor.c
42@@ -50,7 +50,11 @@ static const struct squashfs_decompresso
43 
44 static const struct squashfs_decompressor *decompressor[] = {
45     &squashfs_zlib_comp_ops,
46+#ifdef CONFIG_SQUASHFS_LZMA
47+ &squashfs_lzma_comp_ops,
48+#else
49     &squashfs_lzma_unsupported_comp_ops,
50+#endif
51     &squashfs_lzo_unsupported_comp_ops,
52     &squashfs_unknown_comp_ops
53 };
54--- /dev/null
55+++ b/fs/squashfs/lzma_wrapper.c
56@@ -0,0 +1,151 @@
57+/*
58+ * Squashfs - a compressed read only filesystem for Linux
59+ *
60+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
61+ * Phillip Lougher <phillip@lougher.demon.co.uk>
62+ *
63+ * This program is free software; you can redistribute it and/or
64+ * modify it under the terms of the GNU General Public License
65+ * as published by the Free Software Foundation; either version 2,
66+ * or (at your option) any later version.
67+ *
68+ * This program is distributed in the hope that it will be useful,
69+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
70+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
71+ * GNU General Public License for more details.
72+ *
73+ * You should have received a copy of the GNU General Public License
74+ * along with this program; if not, write to the Free Software
75+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
76+ *
77+ * lzma_wrapper.c
78+ */
79+
80+#include <asm/unaligned.h>
81+#include <linux/buffer_head.h>
82+#include <linux/mutex.h>
83+#include <linux/vmalloc.h>
84+#include <linux/decompress/unlzma.h>
85+
86+#include "squashfs_fs.h"
87+#include "squashfs_fs_sb.h"
88+#include "squashfs_fs_i.h"
89+#include "squashfs.h"
90+#include "decompressor.h"
91+
92+struct squashfs_lzma {
93+ void *input;
94+ void *output;
95+};
96+
97+/* decompress_unlzma.c is currently non re-entrant... */
98+DEFINE_MUTEX(lzma_mutex);
99+
100+/* decompress_unlzma.c doesn't provide any context in its callbacks... */
101+static int lzma_error;
102+
103+static void error(char *m)
104+{
105+ ERROR("unlzma error: %s\n", m);
106+ lzma_error = 1;
107+}
108+
109+
110+static void *lzma_init(struct squashfs_sb_info *msblk)
111+{
112+ struct squashfs_lzma *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
113+ if (stream == NULL)
114+ goto failed;
115+ stream->input = vmalloc(msblk->block_size);
116+ if (stream->input == NULL)
117+ goto failed;
118+ stream->output = vmalloc(msblk->block_size);
119+ if (stream->output == NULL)
120+ goto failed2;
121+
122+ return stream;
123+
124+failed2:
125+ vfree(stream->input);
126+failed:
127+ ERROR("failed to allocate lzma workspace\n");
128+ kfree(stream);
129+ return NULL;
130+}
131+
132+
133+static void lzma_free(void *strm)
134+{
135+ struct squashfs_lzma *stream = strm;
136+
137+ if (stream) {
138+ vfree(stream->input);
139+ vfree(stream->output);
140+ }
141+ kfree(stream);
142+}
143+
144+
145+static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
146+ struct buffer_head **bh, int b, int offset, int length, int srclength,
147+ int pages)
148+{
149+ struct squashfs_lzma *stream = msblk->stream;
150+ void *buff = stream->input;
151+ int avail, i, bytes = length, res;
152+
153+ mutex_lock(&lzma_mutex);
154+
155+ for (i = 0; i < b; i++) {
156+ wait_on_buffer(bh[i]);
157+ if (!buffer_uptodate(bh[i]))
158+ goto block_release;
159+
160+ avail = min(bytes, msblk->devblksize - offset);
161+ memcpy(buff, bh[i]->b_data + offset, avail);
162+ buff += avail;
163+ bytes -= avail;
164+ offset = 0;
165+ put_bh(bh[i]);
166+ }
167+
168+ lzma_error = 0;
169+ res = unlzma(stream->input, length, NULL, NULL, stream->output, NULL,
170+ error);
171+ if (res || lzma_error)
172+ goto failed;
173+
174+ /* uncompressed size is stored in the LZMA header (5 byte offset) */
175+ res = bytes = get_unaligned_le32(stream->input + 5);
176+ for (i = 0, buff = stream->output; bytes && i < pages; i++) {
177+ avail = min_t(int, bytes, PAGE_CACHE_SIZE);
178+ memcpy(buffer[i], buff, avail);
179+ buff += avail;
180+ bytes -= avail;
181+ }
182+ if (bytes)
183+ goto failed;
184+
185+ mutex_unlock(&lzma_mutex);
186+ return res;
187+
188+block_release:
189+ for (; i < b; i++)
190+ put_bh(bh[i]);
191+
192+failed:
193+ mutex_unlock(&lzma_mutex);
194+
195+ ERROR("lzma decompression failed, data probably corrupt\n");
196+ return -EIO;
197+}
198+
199+const struct squashfs_decompressor squashfs_lzma_comp_ops = {
200+ .init = lzma_init,
201+ .free = lzma_free,
202+ .decompress = lzma_uncompress,
203+ .id = LZMA_COMPRESSION,
204+ .name = "lzma",
205+ .supported = 1
206+};
207+
208--- a/fs/squashfs/squashfs.h
209+++ b/fs/squashfs/squashfs.h
210@@ -94,3 +94,6 @@ extern const struct address_space_operat
211 
212 /* zlib_wrapper.c */
213 extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
214+
215+/* lzma wrapper.c */
216+extern const struct squashfs_decompressor squashfs_lzma_comp_ops;
217

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