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