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 DEFINE_MUTEX(deflate_mutex);
  37 static DEFINE_MUTEX(inflate_mutex);
  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 #include <linux/mutex.h>
  44
  45 static int __init alloc_workspaces(void)
  46 {
  47         def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
  48         if (!def_strm.workspace) {
  49                 printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
  50                 return -ENOMEM;
  51         }
  52         D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
  53         inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
  54         if (!inf_strm.workspace) {
  55                 printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
  56                 vfree(def_strm.workspace);
  57                 return -ENOMEM;
  58         }
  59         D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
  60         return 0;
  61 }
  62
  63 static void free_workspaces(void)
  64 {
  65         vfree(def_strm.workspace);
  66         vfree(inf_strm.workspace);
  67 }
  68 #else
  69 #define alloc_workspaces() (0)
  70 #define free_workspaces() do { } while(0)
  71 #endif /* __KERNEL__ */
  72
  73 static int jffs2_zlib_compress(unsigned char *data_in,
  74                                unsigned char *cpage_out,
  75                                uint32_t *sourcelen, uint32_t *dstlen,
  76                                void *model)
  77 {
  78         int ret;
  79
  80         if (*dstlen <= STREAM_END_SPACE)
  81                 return -1;
  82
  83         mutex_lock(&deflate_mutex);
  84
  85         if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
  86                 printk(KERN_WARNING "deflateInit failed\n");
  87                 mutex_unlock(&deflate_mutex);
  88                 return -1;
  89         }
  90
  91         def_strm.next_in = data_in;
  92         def_strm.total_in = 0;
  93
  94         def_strm.next_out = cpage_out;
  95         def_strm.total_out = 0;
  96
  97         while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
  98                 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
  99                 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
 100                 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
 101                           def_strm.avail_in, def_strm.avail_out));
 102                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
 103                 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
 104                           def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
 105                 if (ret != Z_OK) {
 106                         D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
 107                         zlib_deflateEnd(&def_strm);
 108                         mutex_unlock(&deflate_mutex);
 109                         return -1;
 110                 }
 111         }
 112         def_strm.avail_out += STREAM_END_SPACE;
 113         def_strm.avail_in = 0;
 114         ret = zlib_deflate(&def_strm, Z_FINISH);
 115         zlib_deflateEnd(&def_strm);
 116
 117         if (ret != Z_STREAM_END) {
 118                 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
 119                 ret = -1;
 120                 goto out;
 121         }
 122
 123         if (def_strm.total_out >= def_strm.total_in) {
 124                 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
 125                           def_strm.total_in, def_strm.total_out));
 126                 ret = -1;
 127                 goto out;
 128         }
 129
 130         D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
 131                   def_strm.total_in, def_strm.total_out));
 132
 133         *dstlen = def_strm.total_out;
 134         *sourcelen = def_strm.total_in;
 135         ret = 0;
 136  out:
 137         mutex_unlock(&deflate_mutex);
 138         return ret;
 139 }
 140
 141 static int jffs2_zlib_decompress(unsigned char *data_in,
 142                                  unsigned char *cpage_out,
 143                                  uint32_t srclen, uint32_t destlen,
 144                                  void *model)
 145 {
 146         int ret;
 147         int wbits = MAX_WBITS;
 148
 149         mutex_lock(&inflate_mutex);
 150
 151         inf_strm.next_in = data_in;
 152         inf_strm.avail_in = srclen;
 153         inf_strm.total_in = 0;
 154
 155         inf_strm.next_out = cpage_out;
 156         inf_strm.avail_out = destlen;
 157         inf_strm.total_out = 0;
 158
 159         /* If it's deflate, and it's got no preset dictionary, then
 160            we can tell zlib to skip the adler32 check. */
 161         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 162             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 163             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 164
 165                 D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
 166                 wbits = -((data_in[0] >> 4) + 8);
 167                 inf_strm.next_in += 2;
 168                 inf_strm.avail_in -= 2;
 169         } else {
 170                 /* Let this remain D1 for now -- it should never happen */
 171                 D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
 172         }
 173
 174
 175         if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
 176                 printk(KERN_WARNING "inflateInit failed\n");
 177                 mutex_unlock(&inflate_mutex);
 178                 return 1;
 179         }
 180
 181         while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
 182                 ;
 183         if (ret != Z_STREAM_END) {
 184                 printk(KERN_NOTICE "inflate returned %d\n", ret);
 185         }
 186         zlib_inflateEnd(&inf_strm);
 187         mutex_unlock(&inflate_mutex);
 188         return 0;
 189 }
 190
 191 static struct jffs2_compressor jffs2_zlib_comp = {
 192     .priority = JFFS2_ZLIB_PRIORITY,
 193     .name = "zlib",
 194     .compr = JFFS2_COMPR_ZLIB,
 195     .compress = &jffs2_zlib_compress,
 196     .decompress = &jffs2_zlib_decompress,
 197 #ifdef JFFS2_ZLIB_DISABLED
 198     .disabled = 1,
 199 #else
 200     .disabled = 0,
 201 #endif
 202 };
 203
 204 int __init jffs2_zlib_init(void)
 205 {
 206     int ret;
 207
 208     ret = alloc_workspaces();
 209     if (ret)
 210         return ret;
 211
 212     ret = jffs2_register_compressor(&jffs2_zlib_comp);
 213     if (ret)
 214         free_workspaces();
 215
 216     return ret;
 217 }
 218
 219 void jffs2_zlib_exit(void)
 220 {
 221     jffs2_unregister_compressor(&jffs2_zlib_comp);
 222     free_workspaces();
 223 }