New helper - current_umask()
[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  *
6  * Created by David Woodhouse <dwmw2@infradead.org>
7  *
8  * For licensing information, see the file 'LICENCE' in this directory.
9  *
10  */
11
12 #if !defined(__KERNEL__) && !defined(__ECOS)
13 #error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
14 #endif
15
16 #include <linux/kernel.h>
17 #include <linux/slab.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                                void *model)
73 {
74         int ret;
75
76         if (*dstlen <= STREAM_END_SPACE)
77                 return -1;
78
79         mutex_lock(&deflate_mutex);
80
81         if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
82                 printk(KERN_WARNING "deflateInit failed\n");
83                 mutex_unlock(&deflate_mutex);
84                 return -1;
85         }
86
87         def_strm.next_in = data_in;
88         def_strm.total_in = 0;
89
90         def_strm.next_out = cpage_out;
91         def_strm.total_out = 0;
92
93         while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
94                 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
95                 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
96                 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
97                           def_strm.avail_in, def_strm.avail_out));
98                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
99                 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
100                           def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
101                 if (ret != Z_OK) {
102                         D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
103                         zlib_deflateEnd(&def_strm);
104                         mutex_unlock(&deflate_mutex);
105                         return -1;
106                 }
107         }
108         def_strm.avail_out += STREAM_END_SPACE;
109         def_strm.avail_in = 0;
110         ret = zlib_deflate(&def_strm, Z_FINISH);
111         zlib_deflateEnd(&def_strm);
112
113         if (ret != Z_STREAM_END) {
114                 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
115                 ret = -1;
116                 goto out;
117         }
118
119         if (def_strm.total_out >= def_strm.total_in) {
120                 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
121                           def_strm.total_in, def_strm.total_out));
122                 ret = -1;
123                 goto out;
124         }
125
126         D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
127                   def_strm.total_in, def_strm.total_out));
128
129         *dstlen = def_strm.total_out;
130         *sourcelen = def_strm.total_in;
131         ret = 0;
132  out:
133         mutex_unlock(&deflate_mutex);
134         return ret;
135 }
136
137 static int jffs2_zlib_decompress(unsigned char *data_in,
138                                  unsigned char *cpage_out,
139                                  uint32_t srclen, uint32_t destlen,
140                                  void *model)
141 {
142         int ret;
143         int wbits = MAX_WBITS;
144
145         mutex_lock(&inflate_mutex);
146
147         inf_strm.next_in = data_in;
148         inf_strm.avail_in = srclen;
149         inf_strm.total_in = 0;
150
151         inf_strm.next_out = cpage_out;
152         inf_strm.avail_out = destlen;
153         inf_strm.total_out = 0;
154
155         /* If it's deflate, and it's got no preset dictionary, then
156            we can tell zlib to skip the adler32 check. */
157         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
158             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
159             !(((data_in[0]<<8) + data_in[1]) % 31)) {
160
161                 D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
162                 wbits = -((data_in[0] >> 4) + 8);
163                 inf_strm.next_in += 2;
164                 inf_strm.avail_in -= 2;
165         } else {
166                 /* Let this remain D1 for now -- it should never happen */
167                 D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
168         }
169
170
171         if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
172                 printk(KERN_WARNING "inflateInit failed\n");
173                 mutex_unlock(&inflate_mutex);
174                 return 1;
175         }
176
177         while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
178                 ;
179         if (ret != Z_STREAM_END) {
180                 printk(KERN_NOTICE "inflate returned %d\n", ret);
181         }
182         zlib_inflateEnd(&inf_strm);
183         mutex_unlock(&inflate_mutex);
184         return 0;
185 }
186
187 static struct jffs2_compressor jffs2_zlib_comp = {
188     .priority = JFFS2_ZLIB_PRIORITY,
189     .name = "zlib",
190     .compr = JFFS2_COMPR_ZLIB,
191     .compress = &jffs2_zlib_compress,
192     .decompress = &jffs2_zlib_decompress,
193 #ifdef JFFS2_ZLIB_DISABLED
194     .disabled = 1,
195 #else
196     .disabled = 0,
197 #endif
198 };
199
200 int __init jffs2_zlib_init(void)
201 {
202     int ret;
203
204     ret = alloc_workspaces();
205     if (ret)
206             return ret;
207
208     ret = jffs2_register_compressor(&jffs2_zlib_comp);
209     if (ret)
210             free_workspaces();
211
212     return ret;
213 }
214
215 void jffs2_zlib_exit(void)
216 {
217     jffs2_unregister_compressor(&jffs2_zlib_comp);
218     free_workspaces();
219 }