fs/ubifs/compress.c

   1 /*
   2  * This file is part of UBIFS.
   3  *
   4  * Copyright (C) 2006-2008 Nokia Corporation.
   5  * Copyright (C) 2006, 2007 University of Szeged, Hungary
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc., 51
  18  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  *
  20  * Authors: Adrian Hunter
  21  *          Artem Bityutskiy (Битюцкий Артём)
  22  *          Zoltan Sogor
  23  */
  24
  25 /*
  26  * This file provides a single place to access to compression and
  27  * decompression.
  28  */
  29
  30 #include <linux/crypto.h>
  31 #include "ubifs.h"
  32
  33 /* Fake description object for the "none" compressor */
  34 static struct ubifs_compressor none_compr = {
  35         .compr_type = UBIFS_COMPR_NONE,
  36         .name = "none",
  37         .capi_name = "",
  38 };
  39
  40 #ifdef CONFIG_UBIFS_FS_LZO
  41 static DEFINE_MUTEX(lzo_mutex);
  42
  43 static struct ubifs_compressor lzo_compr = {
  44         .compr_type = UBIFS_COMPR_LZO,
  45         .comp_mutex = &lzo_mutex,
  46         .name = "lzo",
  47         .capi_name = "lzo",
  48 };
  49 #else
  50 static struct ubifs_compressor lzo_compr = {
  51         .compr_type = UBIFS_COMPR_LZO,
  52         .name = "lzo",
  53 };
  54 #endif
  55
  56 #if defined(CONFIG_UBIFS_FS_LZ4K)
  57
  58 static DEFINE_MUTEX(lz4k_mutex);
  59
  60
  61 static struct ubifs_compressor lz4k_compr = {
  62         .compr_type = UBIFS_COMPR_LZ4K,
  63         .comp_mutex = &lz4k_mutex,
  64         .name = "lz4k",
  65         .capi_name = "lz4k",
  66 };
  67
  68 #else
  69 static struct ubifs_compressor lz4k_compr = {
  70         .compr_type = UBIFS_COMPR_LZ4K,
  71         .name = "lz4k",
  72 };
  73
  74 #endif
  75
  76
  77 #ifdef CONFIG_UBIFS_FS_ZLIB
  78 static DEFINE_MUTEX(deflate_mutex);
  79 static DEFINE_MUTEX(inflate_mutex);
  80
  81 static struct ubifs_compressor zlib_compr = {
  82         .compr_type = UBIFS_COMPR_ZLIB,
  83         .comp_mutex = &deflate_mutex,
  84         .decomp_mutex = &inflate_mutex,
  85         .name = "zlib",
  86         .capi_name = "deflate",
  87 };
  88 #else
  89 static struct ubifs_compressor zlib_compr = {
  90         .compr_type = UBIFS_COMPR_ZLIB,
  91         .name = "zlib",
  92 };
  93 #endif
  94
  95 /* All UBIFS compressors */
  96 struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
  97
  98 /**
  99  * ubifs_compress - compress data.
 100  * @in_buf: data to compress
 101  * @in_len: length of the data to compress
 102  * @out_buf: output buffer where compressed data should be stored
 103  * @out_len: output buffer length is returned here
 104  * @compr_type: type of compression to use on enter, actually used compression
 105  *              type on exit
 106  *
 107  * This function compresses input buffer @in_buf of length @in_len and stores
 108  * the result in the output buffer @out_buf and the resulting length in
 109  * @out_len. If the input buffer does not compress, it is just copied to the
 110  * @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
 111  * compression error occurred.
 112  *
 113  * Note, if the input buffer was not compressed, it is copied to the output
 114  * buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
 115  */
 116 void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len,
 117                     int *compr_type)
 118 {
 119         int err;
 120         struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
 121
 122         if (*compr_type == UBIFS_COMPR_NONE)
 123                 goto no_compr;
 124
 125         /* If the input data is small, do not even try to compress it */
 126         if (in_len < UBIFS_MIN_COMPR_LEN)
 127                 goto no_compr;
 128
 129         if (compr->comp_mutex)
 130                 mutex_lock(compr->comp_mutex);
 131         err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
 132                                    (unsigned int *)out_len);
 133         if (compr->comp_mutex)
 134                 mutex_unlock(compr->comp_mutex);
 135         if (unlikely(err)) {
 136                 ubifs_warn("cannot compress %d bytes, compressor %s, error %d, leave data uncompressed",
 137                            in_len, compr->name, err);
 138                  goto no_compr;
 139         }
 140
 141         /*
 142          * If the data compressed only slightly, it is better to leave it
 143          * uncompressed to improve read speed.
 144          */
 145         if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF)
 146                 goto no_compr;
 147
 148         return;
 149
 150 no_compr:
 151         memcpy(out_buf, in_buf, in_len);
 152         *out_len = in_len;
 153         *compr_type = UBIFS_COMPR_NONE;
 154 }
 155
 156 /**
 157  * ubifs_decompress - decompress data.
 158  * @in_buf: data to decompress
 159  * @in_len: length of the data to decompress
 160  * @out_buf: output buffer where decompressed data should
 161  * @out_len: output length is returned here
 162  * @compr_type: type of compression
 163  *
 164  * This function decompresses data from buffer @in_buf into buffer @out_buf.
 165  * The length of the uncompressed data is returned in @out_len. This functions
 166  * returns %0 on success or a negative error code on failure.
 167  */
 168 int ubifs_decompress(const void *in_buf, int in_len, void *out_buf,
 169                      int *out_len, int compr_type)
 170 {
 171         int err;
 172         struct ubifs_compressor *compr;
 173
 174         if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
 175                 ubifs_err("invalid compression type %d", compr_type);
 176                 return -EINVAL;
 177         }
 178
 179         compr = ubifs_compressors[compr_type];
 180
 181         if (unlikely(!compr->capi_name)) {
 182                 ubifs_err("%s compression is not compiled in", compr->name);
 183                 return -EINVAL;
 184         }
 185
 186         if (compr_type == UBIFS_COMPR_NONE) {
 187                 memcpy(out_buf, in_buf, in_len);
 188                 *out_len = in_len;
 189                 return 0;
 190         }
 191
 192         if (compr->decomp_mutex)
 193                 mutex_lock(compr->decomp_mutex);
 194         err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
 195                                      (unsigned int *)out_len);
 196         if (compr->decomp_mutex)
 197                 mutex_unlock(compr->decomp_mutex);
 198         if (err)
 199                 ubifs_err("cannot decompress %d bytes, compressor %s, error %d",
 200                           in_len, compr->name, err);
 201
 202         return err;
 203 }
 204
 205 /**
 206  * compr_init - initialize a compressor.
 207  * @compr: compressor description object
 208  *
 209  * This function initializes the requested compressor and returns zero in case
 210  * of success or a negative error code in case of failure.
 211  */
 212 static int __init compr_init(struct ubifs_compressor *compr)
 213 {
 214         if (compr->capi_name) {
 215                 compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
 216                 if (IS_ERR(compr->cc)) {
 217                         ubifs_err("cannot initialize compressor %s, error %ld",
 218                                   compr->name, PTR_ERR(compr->cc));
 219                         return PTR_ERR(compr->cc);
 220                 }
 221         }
 222
 223         ubifs_compressors[compr->compr_type] = compr;
 224         return 0;
 225 }
 226
 227 /**
 228  * compr_exit - de-initialize a compressor.
 229  * @compr: compressor description object
 230  */
 231 static void compr_exit(struct ubifs_compressor *compr)
 232 {
 233         if (compr->capi_name)
 234                 crypto_free_comp(compr->cc);
 235         return;
 236 }
 237
 238 /**
 239  * ubifs_compressors_init - initialize UBIFS compressors.
 240  *
 241  * This function initializes the compressor which were compiled in. Returns
 242  * zero in case of success and a negative error code in case of failure.
 243  */
 244 int __init ubifs_compressors_init(void)
 245 {
 246         int err;
 247
 248         err = compr_init(&lzo_compr);
 249         if (err)
 250                 return err;
 251
 252         err = compr_init(&zlib_compr);
 253         if (err)
 254                 goto out_lzo;
 255
 256
 257         err = compr_init(&lz4k_compr);
 258         if (err)
 259                 goto out_lzo;
 260
 261         ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
 262         return 0;
 263
 264 out_lzo:
 265         compr_exit(&lzo_compr);
 266
 267         compr_exit(&lz4k_compr);
 268
 269
 270         return err;
 271 }
 272
 273 /**
 274  * ubifs_compressors_exit - de-initialize UBIFS compressors.
 275  */
 276 void ubifs_compressors_exit(void)
 277 {
 278         compr_exit(&lzo_compr);
 279         compr_exit(&zlib_compr);
 280 }