lockd: Introduce new-style XDR functions for NLMv3
[linux-2.6.git] / fs / jffs2 / compr_zlib.c
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright © 2001-2007 Red Hat, Inc.
5  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
6  *
7  * Created by David Woodhouse <dwmw2@infradead.org>
8  *
9  * For licensing information, see the file 'LICENCE' in this directory.
10  *
11  */
12
13 #if !defined(__KERNEL__) && !defined(__ECOS)
14 #error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
15 #endif
16
17 #include <linux/kernel.h>
18 #include <linux/zlib.h>
19 #include <linux/zutil.h>
20 #include "nodelist.h"
21 #include "compr.h"
22
23         /* Plan: call deflate() with avail_in == *sourcelen,
24                 avail_out = *dstlen - 12 and flush == Z_FINISH.
25                 If it doesn't manage to finish, call it again with
26                 avail_in == 0 and avail_out set to the remaining 12
27                 bytes for it to clean up.
28            Q: Is 12 bytes sufficient?
29         */
30 #define STREAM_END_SPACE 12
31
32 static DEFINE_MUTEX(deflate_mutex);
33 static DEFINE_MUTEX(inflate_mutex);
34 static z_stream inf_strm, def_strm;
35
36 #ifdef __KERNEL__ /* Linux-only */
37 #include <linux/vmalloc.h>
38 #include <linux/init.h>
39 #include <linux/mutex.h>
40
41 static int __init alloc_workspaces(void)
42 {
43         def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
44         if (!def_strm.workspace) {
45                 printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
46                 return -ENOMEM;
47         }
48         D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
49         inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
50         if (!inf_strm.workspace) {
51                 printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
52                 vfree(def_strm.workspace);
53                 return -ENOMEM;
54         }
55         D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
56         return 0;
57 }
58
59 static void free_workspaces(void)
60 {
61         vfree(def_strm.workspace);
62         vfree(inf_strm.workspace);
63 }
64 #else
65 #define alloc_workspaces() (0)
66 #define free_workspaces() do { } while(0)
67 #endif /* __KERNEL__ */
68
69 static int jffs2_zlib_compress(unsigned char *data_in,
70                                unsigned char *cpage_out,
71                                uint32_t *sourcelen, uint32_t *dstlen)
72 {
73         int ret;
74
75         if (*dstlen <= STREAM_END_SPACE)
76                 return -1;
77
78         mutex_lock(&deflate_mutex);
79
80         if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
81                 printk(KERN_WARNING "deflateInit failed\n");
82                 mutex_unlock(&deflate_mutex);
83                 return -1;
84         }
85
86         def_strm.next_in = data_in;
87         def_strm.total_in = 0;
88
89         def_strm.next_out = cpage_out;
90         def_strm.total_out = 0;
91
92         while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
93                 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
94                 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
95                 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
96                           def_strm.avail_in, def_strm.avail_out));
97                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
98                 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
99                           def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
100                 if (ret != Z_OK) {
101                         D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
102                         zlib_deflateEnd(&def_strm);
103                         mutex_unlock(&deflate_mutex);
104                         return -1;
105                 }
106         }
107         def_strm.avail_out += STREAM_END_SPACE;
108         def_strm.avail_in = 0;
109         ret = zlib_deflate(&def_strm, Z_FINISH);
110         zlib_deflateEnd(&def_strm);
111
112         if (ret != Z_STREAM_END) {
113                 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
114                 ret = -1;
115                 goto out;
116         }
117
118         if (def_strm.total_out >= def_strm.total_in) {
119                 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
120                           def_strm.total_in, def_strm.total_out));
121                 ret = -1;
122                 goto out;
123         }
124
125         D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
126                   def_strm.total_in, def_strm.total_out));
127
128         *dstlen = def_strm.total_out;
129         *sourcelen = def_strm.total_in;
130         ret = 0;
131  out:
132         mutex_unlock(&deflate_mutex);
133         return ret;
134 }
135
136 static int jffs2_zlib_decompress(unsigned char *data_in,
137                                  unsigned char *cpage_out,
138                                  uint32_t srclen, uint32_t destlen)
139 {
140         int ret;
141         int wbits = MAX_WBITS;
142
143         mutex_lock(&inflate_mutex);
144
145         inf_strm.next_in = data_in;
146         inf_strm.avail_in = srclen;
147         inf_strm.total_in = 0;
148
149         inf_strm.next_out = cpage_out;
150         inf_strm.avail_out = destlen;
151         inf_strm.total_out = 0;
152
153         /* If it's deflate, and it's got no preset dictionary, then
154            we can tell zlib to skip the adler32 check. */
155         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
156             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
157             !(((data_in[0]<<8) + data_in[1]) % 31)) {
158
159                 D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
160                 wbits = -((data_in[0] >> 4) + 8);
161                 inf_strm.next_in += 2;
162                 inf_strm.avail_in -= 2;
163         } else {
164                 /* Let this remain D1 for now -- it should never happen */
165                 D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
166         }
167
168
169         if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
170                 printk(KERN_WARNING "inflateInit failed\n");
171                 mutex_unlock(&inflate_mutex);
172                 return 1;
173         }
174
175         while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
176                 ;
177         if (ret != Z_STREAM_END) {
178                 printk(KERN_NOTICE "inflate returned %d\n", ret);
179         }
180         zlib_inflateEnd(&inf_strm);
181         mutex_unlock(&inflate_mutex);
182         return 0;
183 }
184
185 static struct jffs2_compressor jffs2_zlib_comp = {
186     .priority = JFFS2_ZLIB_PRIORITY,
187     .name = "zlib",
188     .compr = JFFS2_COMPR_ZLIB,
189     .compress = &jffs2_zlib_compress,
190     .decompress = &jffs2_zlib_decompress,
191 #ifdef JFFS2_ZLIB_DISABLED
192     .disabled = 1,
193 #else
194     .disabled = 0,
195 #endif
196 };
197
198 int __init jffs2_zlib_init(void)
199 {
200     int ret;
201
202     ret = alloc_workspaces();
203     if (ret)
204             return ret;
205
206     ret = jffs2_register_compressor(&jffs2_zlib_comp);
207     if (ret)
208             free_workspaces();
209
210     return ret;
211 }
212
213 void jffs2_zlib_exit(void)
214 {
215     jffs2_unregister_compressor(&jffs2_zlib_comp);
216     free_workspaces();
217 }