blob: c4eb400182564c13728fc88f95edf6db294eb2ac [file] [log] [blame]
Phillip Lougher81bb8de2010-12-09 02:02:29 +00001/*
2 * Squashfs - a compressed read only filesystem for Linux
3 *
4 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
5 * Phillip Lougher <phillip@lougher.demon.co.uk>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2,
10 * or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 *
21 * xz_wrapper.c
22 */
23
24
25#include <linux/mutex.h>
26#include <linux/buffer_head.h>
27#include <linux/slab.h>
28#include <linux/xz.h>
29
30#include "squashfs_fs.h"
31#include "squashfs_fs_sb.h"
32#include "squashfs_fs_i.h"
33#include "squashfs.h"
34#include "decompressor.h"
35
36struct squashfs_xz {
37 struct xz_dec *state;
38 struct xz_buf buf;
39};
40
41static void *squashfs_xz_init(struct squashfs_sb_info *msblk)
42{
43 int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
44
45 struct squashfs_xz *stream = kmalloc(sizeof(*stream), GFP_KERNEL);
46 if (stream == NULL)
47 goto failed;
48
49 stream->state = xz_dec_init(XZ_PREALLOC, block_size);
50 if (stream->state == NULL)
51 goto failed;
52
53 return stream;
54
55failed:
56 ERROR("Failed to allocate xz workspace\n");
57 kfree(stream);
58 return NULL;
59}
60
61
62static void squashfs_xz_free(void *strm)
63{
64 struct squashfs_xz *stream = strm;
65
66 if (stream) {
67 xz_dec_end(stream->state);
68 kfree(stream);
69 }
70}
71
72
73static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer,
74 struct buffer_head **bh, int b, int offset, int length, int srclength,
75 int pages)
76{
77 enum xz_ret xz_err;
78 int avail, total = 0, k = 0, page = 0;
79 struct squashfs_xz *stream = msblk->stream;
80
81 mutex_lock(&msblk->read_data_mutex);
82
83 xz_dec_reset(stream->state);
84 stream->buf.in_pos = 0;
85 stream->buf.in_size = 0;
86 stream->buf.out_pos = 0;
87 stream->buf.out_size = PAGE_CACHE_SIZE;
88 stream->buf.out = buffer[page++];
89
90 do {
91 if (stream->buf.in_pos == stream->buf.in_size && k < b) {
92 avail = min(length, msblk->devblksize - offset);
93 length -= avail;
94 wait_on_buffer(bh[k]);
95 if (!buffer_uptodate(bh[k]))
96 goto release_mutex;
97
Phillip Lougher81bb8de2010-12-09 02:02:29 +000098 stream->buf.in = bh[k]->b_data + offset;
99 stream->buf.in_size = avail;
100 stream->buf.in_pos = 0;
101 offset = 0;
102 }
103
104 if (stream->buf.out_pos == stream->buf.out_size
105 && page < pages) {
106 stream->buf.out = buffer[page++];
107 stream->buf.out_pos = 0;
108 total += PAGE_CACHE_SIZE;
109 }
110
111 xz_err = xz_dec_run(stream->state, &stream->buf);
112
113 if (stream->buf.in_pos == stream->buf.in_size && k < b)
114 put_bh(bh[k++]);
115 } while (xz_err == XZ_OK);
116
117 if (xz_err != XZ_STREAM_END) {
118 ERROR("xz_dec_run error, data probably corrupt\n");
119 goto release_mutex;
120 }
121
122 if (k < b) {
123 ERROR("xz_uncompress error, input remaining\n");
124 goto release_mutex;
125 }
126
127 total += stream->buf.out_pos;
128 mutex_unlock(&msblk->read_data_mutex);
129 return total;
130
131release_mutex:
132 mutex_unlock(&msblk->read_data_mutex);
133
134 for (; k < b; k++)
135 put_bh(bh[k]);
136
137 return -EIO;
138}
139
140const struct squashfs_decompressor squashfs_xz_comp_ops = {
141 .init = squashfs_xz_init,
142 .free = squashfs_xz_free,
143 .decompress = squashfs_xz_uncompress,
144 .id = XZ_COMPRESSION,
145 .name = "xz",
146 .supported = 1
147};