4db8be8e90cc09dea0f71d09d55048d612bbb17a
[linux-2.6.git] / fs / jffs2 / compr_zlib.c
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright (C) 2001-2003 Red Hat, Inc.
5  *
6  * Created by David Woodhouse <dwmw2@infradead.org>
7  *
8  * For licensing information, see the file 'LICENCE' in this directory.
9  *
10  * $Id: compr_zlib.c,v 1.32 2005/11/07 11:14:38 gleixner Exp $
11  *
12  */
13
14 #if !defined(__KERNEL__) && !defined(__ECOS)
15 #error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
16 #endif
17
18 #include <linux/config.h>
19 #include <linux/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/zlib.h>
23 #include <linux/zutil.h>
24 #include "nodelist.h"
25 #include "compr.h"
26
27         /* Plan: call deflate() with avail_in == *sourcelen,
28                 avail_out = *dstlen - 12 and flush == Z_FINISH.
29                 If it doesn't manage to finish, call it again with
30                 avail_in == 0 and avail_out set to the remaining 12
31                 bytes for it to clean up.
32            Q: Is 12 bytes sufficient?
33         */
34 #define STREAM_END_SPACE 12
35
36 static DECLARE_MUTEX(deflate_sem);
37 static DECLARE_MUTEX(inflate_sem);
38 static z_stream inf_strm, def_strm;
39
40 #ifdef __KERNEL__ /* Linux-only */
41 #include <linux/vmalloc.h>
42 #include <linux/init.h>
43
44 static int __init alloc_workspaces(void)
45 {
46         def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
47         if (!def_strm.workspace) {
48                 printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
49                 return -ENOMEM;
50         }
51         D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
52         inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
53         if (!inf_strm.workspace) {
54                 printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
55                 vfree(def_strm.workspace);
56                 return -ENOMEM;
57         }
58         D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
59         return 0;
60 }
61
62 static void free_workspaces(void)
63 {
64         vfree(def_strm.workspace);
65         vfree(inf_strm.workspace);
66 }
67 #else
68 #define alloc_workspaces() (0)
69 #define free_workspaces() do { } while(0)
70 #endif /* __KERNEL__ */
71
72 static int jffs2_zlib_compress(unsigned char *data_in,
73                                unsigned char *cpage_out,
74                                uint32_t *sourcelen, uint32_t *dstlen,
75                                void *model)
76 {
77         int ret;
78
79         if (*dstlen <= STREAM_END_SPACE)
80                 return -1;
81
82         down(&deflate_sem);
83
84         if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
85                 printk(KERN_WARNING "deflateInit failed\n");
86                 up(&deflate_sem);
87                 return -1;
88         }
89
90         def_strm.next_in = data_in;
91         def_strm.total_in = 0;
92
93         def_strm.next_out = cpage_out;
94         def_strm.total_out = 0;
95
96         while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
97                 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
98                 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
99                 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
100                           def_strm.avail_in, def_strm.avail_out));
101                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
102                 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
103                           def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
104                 if (ret != Z_OK) {
105                         D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
106                         zlib_deflateEnd(&def_strm);
107                         up(&deflate_sem);
108                         return -1;
109                 }
110         }
111         def_strm.avail_out += STREAM_END_SPACE;
112         def_strm.avail_in = 0;
113         ret = zlib_deflate(&def_strm, Z_FINISH);
114         zlib_deflateEnd(&def_strm);
115
116         if (ret != Z_STREAM_END) {
117                 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
118                 ret = -1;
119                 goto out;
120         }
121
122         if (def_strm.total_out >= def_strm.total_in) {
123                 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
124                           def_strm.total_in, def_strm.total_out));
125                 ret = -1;
126                 goto out;
127         }
128
129         D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
130                   def_strm.total_in, def_strm.total_out));
131
132         *dstlen = def_strm.total_out;
133         *sourcelen = def_strm.total_in;
134         ret = 0;
135  out:
136         up(&deflate_sem);
137         return ret;
138 }
139
140 static int jffs2_zlib_decompress(unsigned char *data_in,
141                                  unsigned char *cpage_out,
142                                  uint32_t srclen, uint32_t destlen,
143                                  void *model)
144 {
145         int ret;
146         int wbits = MAX_WBITS;
147
148         down(&inflate_sem);
149
150         inf_strm.next_in = data_in;
151         inf_strm.avail_in = srclen;
152         inf_strm.total_in = 0;
153
154         inf_strm.next_out = cpage_out;
155         inf_strm.avail_out = destlen;
156         inf_strm.total_out = 0;
157
158         /* If it's deflate, and it's got no preset dictionary, then
159            we can tell zlib to skip the adler32 check. */
160         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
161             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
162             !(((data_in[0]<<8) + data_in[1]) % 31)) {
163
164                 D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
165                 wbits = -((data_in[0] >> 4) + 8);
166                 inf_strm.next_in += 2;
167                 inf_strm.avail_in -= 2;
168         } else {
169                 /* Let this remain D1 for now -- it should never happen */
170                 D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
171         }
172
173
174         if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
175                 printk(KERN_WARNING "inflateInit failed\n");
176                 up(&inflate_sem);
177                 return 1;
178         }
179
180         while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
181                 ;
182         if (ret != Z_STREAM_END) {
183                 printk(KERN_NOTICE "inflate returned %d\n", ret);
184         }
185         zlib_inflateEnd(&inf_strm);
186         up(&inflate_sem);
187         return 0;
188 }
189
190 static struct jffs2_compressor jffs2_zlib_comp = {
191     .priority = JFFS2_ZLIB_PRIORITY,
192     .name = "zlib",
193     .compr = JFFS2_COMPR_ZLIB,
194     .compress = &jffs2_zlib_compress,
195     .decompress = &jffs2_zlib_decompress,
196 #ifdef JFFS2_ZLIB_DISABLED
197     .disabled = 1,
198 #else
199     .disabled = 0,
200 #endif
201 };
202
203 int __init jffs2_zlib_init(void)
204 {
205     int ret;
206
207     ret = alloc_workspaces();
208     if (ret)
209         return ret;
210
211     ret = jffs2_register_compressor(&jffs2_zlib_comp);
212     if (ret)
213         free_workspaces();
214
215     return ret;
216 }
217
218 void jffs2_zlib_exit(void)
219 {
220     jffs2_unregister_compressor(&jffs2_zlib_comp);
221     free_workspaces();
222 }