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