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