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@redhat.com>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  * $Id: compr_zlib.c,v 1.28 2004/06/23 16:34:40 havasi 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/slab.h>
  21 #include <linux/zlib.h>
  22 #include <linux/zutil.h>
  23 #include <asm/semaphore.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 DECLARE_MUTEX(deflate_sem);
  37 static DECLARE_MUTEX(inflate_sem);
  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
  44 static int __init alloc_workspaces(void)
  45 {
  46         def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
  47         if (!def_strm.workspace) {
  48                 printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
  49                 return -ENOMEM;
  50         }
  51         D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
  52         inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
  53         if (!inf_strm.workspace) {
  54                 printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
  55                 vfree(def_strm.workspace);
  56                 return -ENOMEM;
  57         }
  58         D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", 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 int jffs2_zlib_compress(unsigned char *data_in, unsigned char *cpage_out,
  73                    uint32_t *sourcelen, uint32_t *dstlen, void *model)
  74 {
  75         int ret;
  76
  77         if (*dstlen <= STREAM_END_SPACE)
  78                 return -1;
  79
  80         down(&deflate_sem);
  81
  82         if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
  83                 printk(KERN_WARNING "deflateInit failed\n");
  84                 up(&deflate_sem);
  85                 return -1;
  86         }
  87
  88         def_strm.next_in = data_in;
  89         def_strm.total_in = 0;
  90
  91         def_strm.next_out = cpage_out;
  92         def_strm.total_out = 0;
  93
  94         while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
  95                 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
  96                 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
  97                 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
  98                           def_strm.avail_in, def_strm.avail_out));
  99                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
 100                 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
 101                           def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
 102                 if (ret != Z_OK) {
 103                         D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
 104                         zlib_deflateEnd(&def_strm);
 105                         up(&deflate_sem);
 106                         return -1;
 107                 }
 108         }
 109         def_strm.avail_out += STREAM_END_SPACE;
 110         def_strm.avail_in = 0;
 111         ret = zlib_deflate(&def_strm, Z_FINISH);
 112         zlib_deflateEnd(&def_strm);
 113
 114         if (ret != Z_STREAM_END) {
 115                 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
 116                 ret = -1;
 117                 goto out;
 118         }
 119
 120         if (def_strm.total_out >= def_strm.total_in) {
 121                 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
 122                           def_strm.total_in, def_strm.total_out));
 123                 ret = -1;
 124                 goto out;
 125         }
 126
 127         D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
 128                   def_strm.total_in, def_strm.total_out));
 129
 130         *dstlen = def_strm.total_out;
 131         *sourcelen = def_strm.total_in;
 132         ret = 0;
 133  out:
 134         up(&deflate_sem);
 135         return ret;
 136 }
 137
 138 int jffs2_zlib_decompress(unsigned char *data_in, unsigned char *cpage_out,
 139                       uint32_t srclen, uint32_t destlen, void *model)
 140 {
 141         int ret;
 142         int wbits = MAX_WBITS;
 143
 144         down(&inflate_sem);
 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                 up(&inflate_sem);
 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         up(&inflate_sem);
 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 }