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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19 #include <linux/kernel.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(MAX_WBITS,
  46                                                         MAX_MEM_LEVEL));
  47         if (!def_strm.workspace)
  48                 return -ENOMEM;
  49
  50         jffs2_dbg(1, "Allocated %d bytes for deflate workspace\n",
  51                   zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL));
  52         inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
  53         if (!inf_strm.workspace) {
  54                 vfree(def_strm.workspace);
  55                 return -ENOMEM;
  56         }
  57         jffs2_dbg(1, "Allocated %d bytes for inflate workspace\n",
  58                   zlib_inflate_workspacesize());
  59         return 0;
  60 }
  61
  62 static void free_workspaces(void)
  63 {
  64         vfree(def_strm.workspace);
  65         vfree(inf_strm.workspace);
  66 }
  67 #else
  68 #define alloc_workspaces() (0)
  69 #define free_workspaces() do { } while(0)
  70 #endif /* __KERNEL__ */
  71
  72 static int jffs2_zlib_compress(unsigned char *data_in,
  73                                unsigned char *cpage_out,
  74                                uint32_t *sourcelen, uint32_t *dstlen)
  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                 pr_warn("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_t(unsigned long,
  98                         (*sourcelen-def_strm.total_in), def_strm.avail_out);
  99                 jffs2_dbg(1, "calling deflate with avail_in %ld, avail_out %ld\n",
 100                           def_strm.avail_in, def_strm.avail_out);
 101                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
 102                 jffs2_dbg(1, "deflate returned with avail_in %ld, avail_out %ld, total_in %ld, total_out %ld\n",
 103                           def_strm.avail_in, def_strm.avail_out,
 104                           def_strm.total_in, def_strm.total_out);
 105                 if (ret != Z_OK) {
 106                         jffs2_dbg(1, "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                 jffs2_dbg(1, "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                 jffs2_dbg(1, "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         jffs2_dbg(1, "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 {
 145         int ret;
 146         int wbits = MAX_WBITS;
 147
 148         mutex_lock(&inflate_mutex);
 149
 150         inf_strm.next_in = data_in;
 151         inf_strm.avail_in = srclen;
 152         inf_strm.total_in = 0;
 153
 154         inf_strm.next_out = cpage_out;
 155         inf_strm.avail_out = destlen;
 156         inf_strm.total_out = 0;
 157
 158         /* If it's deflate, and it's got no preset dictionary, then
 159            we can tell zlib to skip the adler32 check. */
 160         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 161             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 162             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 163
 164                 jffs2_dbg(2, "inflate skipping adler32\n");
 165                 wbits = -((data_in[0] >> 4) + 8);
 166                 inf_strm.next_in += 2;
 167                 inf_strm.avail_in -= 2;
 168         } else {
 169                 /* Let this remain D1 for now -- it should never happen */
 170                 jffs2_dbg(1, "inflate not skipping adler32\n");
 171         }
 172
 173
 174         if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
 175                 pr_warn("inflateInit failed\n");
 176                 mutex_unlock(&inflate_mutex);
 177                 return 1;
 178         }
 179
 180         while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
 181                 ;
 182         if (ret != Z_STREAM_END) {
 183                 pr_notice("inflate returned %d\n", ret);
 184         }
 185         zlib_inflateEnd(&inf_strm);
 186         mutex_unlock(&inflate_mutex);
 187         return 0;
 188 }
 189
 190 static struct jffs2_compressor jffs2_zlib_comp = {
 191     .priority = JFFS2_ZLIB_PRIORITY,
 192     .name = "zlib",
 193     .compr = JFFS2_COMPR_ZLIB,
 194     .compress = &jffs2_zlib_compress,
 195     .decompress = &jffs2_zlib_decompress,
 196 #ifdef JFFS2_ZLIB_DISABLED
 197     .disabled = 1,
 198 #else
 199     .disabled = 0,
 200 #endif
 201 };
 202
 203 int __init jffs2_zlib_init(void)
 204 {
 205     int ret;
 206
 207     ret = alloc_workspaces();
 208     if (ret)
 209             return ret;
 210
 211     ret = jffs2_register_compressor(&jffs2_zlib_comp);
 212     if (ret)
 213             free_workspaces();
 214
 215     return ret;
 216 }
 217
 218 void jffs2_zlib_exit(void)
 219 {
 220     jffs2_unregister_compressor(&jffs2_zlib_comp);
 221     free_workspaces();
 222 }