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(MAX_WBITS,
  44                                                         MAX_MEM_LEVEL));
  45         if (!def_strm.workspace)
  46                 return -ENOMEM;
  47
  48         D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL)));
  49         inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
  50         if (!inf_strm.workspace) {
  51                 vfree(def_strm.workspace);
  52                 return -ENOMEM;
  53         }
  54         D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
  55         return 0;
  56 }
  57
  58 static void free_workspaces(void)
  59 {
  60         vfree(def_strm.workspace);
  61         vfree(inf_strm.workspace);
  62 }
  63 #else
  64 #define alloc_workspaces() (0)
  65 #define free_workspaces() do { } while(0)
  66 #endif /* __KERNEL__ */
  67
  68 static int jffs2_zlib_compress(unsigned char *data_in,
  69                                unsigned char *cpage_out,
  70                                uint32_t *sourcelen, uint32_t *dstlen)
  71 {
  72         int ret;
  73
  74         if (*dstlen <= STREAM_END_SPACE)
  75                 return -1;
  76
  77         mutex_lock(&deflate_mutex);
  78
  79         if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
  80                 printk(KERN_WARNING "deflateInit failed\n");
  81                 mutex_unlock(&deflate_mutex);
  82                 return -1;
  83         }
  84
  85         def_strm.next_in = data_in;
  86         def_strm.total_in = 0;
  87
  88         def_strm.next_out = cpage_out;
  89         def_strm.total_out = 0;
  90
  91         while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
  92                 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
  93                 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
  94                 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
  95                           def_strm.avail_in, def_strm.avail_out));
  96                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
  97                 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
  98                           def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
  99                 if (ret != Z_OK) {
 100                         D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
 101                         zlib_deflateEnd(&def_strm);
 102                         mutex_unlock(&deflate_mutex);
 103                         return -1;
 104                 }
 105         }
 106         def_strm.avail_out += STREAM_END_SPACE;
 107         def_strm.avail_in = 0;
 108         ret = zlib_deflate(&def_strm, Z_FINISH);
 109         zlib_deflateEnd(&def_strm);
 110
 111         if (ret != Z_STREAM_END) {
 112                 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
 113                 ret = -1;
 114                 goto out;
 115         }
 116
 117         if (def_strm.total_out >= def_strm.total_in) {
 118                 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
 119                           def_strm.total_in, def_strm.total_out));
 120                 ret = -1;
 121                 goto out;
 122         }
 123
 124         D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
 125                   def_strm.total_in, def_strm.total_out));
 126
 127         *dstlen = def_strm.total_out;
 128         *sourcelen = def_strm.total_in;
 129         ret = 0;
 130  out:
 131         mutex_unlock(&deflate_mutex);
 132         return ret;
 133 }
 134
 135 static int jffs2_zlib_decompress(unsigned char *data_in,
 136                                  unsigned char *cpage_out,
 137                                  uint32_t srclen, uint32_t destlen)
 138 {
 139         int ret;
 140         int wbits = MAX_WBITS;
 141
 142         mutex_lock(&inflate_mutex);
 143
 144         inf_strm.next_in = data_in;
 145         inf_strm.avail_in = srclen;
 146         inf_strm.total_in = 0;
 147
 148         inf_strm.next_out = cpage_out;
 149         inf_strm.avail_out = destlen;
 150         inf_strm.total_out = 0;
 151
 152         /* If it's deflate, and it's got no preset dictionary, then
 153            we can tell zlib to skip the adler32 check. */
 154         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 155             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 156             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 157
 158                 D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
 159                 wbits = -((data_in[0] >> 4) + 8);
 160                 inf_strm.next_in += 2;
 161                 inf_strm.avail_in -= 2;
 162         } else {
 163                 /* Let this remain D1 for now -- it should never happen */
 164                 D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
 165         }
 166
 167
 168         if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
 169                 printk(KERN_WARNING "inflateInit failed\n");
 170                 mutex_unlock(&inflate_mutex);
 171                 return 1;
 172         }
 173
 174         while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
 175                 ;
 176         if (ret != Z_STREAM_END) {
 177                 printk(KERN_NOTICE "inflate returned %d\n", ret);
 178         }
 179         zlib_inflateEnd(&inf_strm);
 180         mutex_unlock(&inflate_mutex);
 181         return 0;
 182 }
 183
 184 static struct jffs2_compressor jffs2_zlib_comp = {
 185     .priority = JFFS2_ZLIB_PRIORITY,
 186     .name = "zlib",
 187     .compr = JFFS2_COMPR_ZLIB,
 188     .compress = &jffs2_zlib_compress,
 189     .decompress = &jffs2_zlib_decompress,
 190 #ifdef JFFS2_ZLIB_DISABLED
 191     .disabled = 1,
 192 #else
 193     .disabled = 0,
 194 #endif
 195 };
 196
 197 int __init jffs2_zlib_init(void)
 198 {
 199     int ret;
 200
 201     ret = alloc_workspaces();
 202     if (ret)
 203             return ret;
 204
 205     ret = jffs2_register_compressor(&jffs2_zlib_comp);
 206     if (ret)
 207             free_workspaces();
 208
 209     return ret;
 210 }
 211
 212 void jffs2_zlib_exit(void)
 213 {
 214     jffs2_unregister_compressor(&jffs2_zlib_comp);
 215     free_workspaces();
 216 }