fs/ubifs/compress.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This file is part of UBIFS.
   4  *
   5  * Copyright (C) 2006-2008 Nokia Corporation.
   6  * Copyright (C) 2006, 2007 University of Szeged, Hungary
   7  *
   8  * Authors: Adrian Hunter
   9  *          Artem Bityutskiy (Битюцкий Артём)
  10  *          Zoltan Sogor
  11  */
  12
  13 /*
  14  * This file provides a single place to access to compression and
  15  * decompression.
  16  */
  17
  18 #include <linux/crypto.h>
  19 #include "ubifs.h"
  20
  21 /* Fake description object for the "none" compressor */
  22 static struct ubifs_compressor none_compr = {
  23         .compr_type = UBIFS_COMPR_NONE,
  24         .name = "none",
  25         .capi_name = "",
  26 };
  27
  28 #ifdef CONFIG_UBIFS_FS_LZO
  29 static DEFINE_MUTEX(lzo_mutex);
  30
  31 static struct ubifs_compressor lzo_compr = {
  32         .compr_type = UBIFS_COMPR_LZO,
  33         .comp_mutex = &lzo_mutex,
  34         .name = "lzo",
  35         .capi_name = "lzo",
  36 };
  37 #else
  38 static struct ubifs_compressor lzo_compr = {
  39         .compr_type = UBIFS_COMPR_LZO,
  40         .name = "lzo",
  41 };
  42 #endif
  43
  44 #ifdef CONFIG_UBIFS_FS_ZLIB
  45 static DEFINE_MUTEX(deflate_mutex);
  46 static DEFINE_MUTEX(inflate_mutex);
  47
  48 static struct ubifs_compressor zlib_compr = {
  49         .compr_type = UBIFS_COMPR_ZLIB,
  50         .comp_mutex = &deflate_mutex,
  51         .decomp_mutex = &inflate_mutex,
  52         .name = "zlib",
  53         .capi_name = "deflate",
  54 };
  55 #else
  56 static struct ubifs_compressor zlib_compr = {
  57         .compr_type = UBIFS_COMPR_ZLIB,
  58         .name = "zlib",
  59 };
  60 #endif
  61
  62 /* All UBIFS compressors */
  63 struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
  64
  65 /**
  66  * ubifs_compress - compress data.
  67  * @in_buf: data to compress
  68  * @in_len: length of the data to compress
  69  * @out_buf: output buffer where compressed data should be stored
  70  * @out_len: output buffer length is returned here
  71  * @compr_type: type of compression to use on enter, actually used compression
  72  *              type on exit
  73  *
  74  * This function compresses input buffer @in_buf of length @in_len and stores
  75  * the result in the output buffer @out_buf and the resulting length in
  76  * @out_len. If the input buffer does not compress, it is just copied to the
  77  * @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
  78  * compression error occurred.
  79  *
  80  * Note, if the input buffer was not compressed, it is copied to the output
  81  * buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
  82  */
  83 void ubifs_compress(const struct ubifs_info *c, const void *in_buf,
  84                     int in_len, void *out_buf, int *out_len, int *compr_type)
  85 {
  86         int err;
  87         struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
  88
  89         if (*compr_type == UBIFS_COMPR_NONE)
  90                 goto no_compr;
  91
  92         /* If the input data is small, do not even try to compress it */
  93         if (in_len < UBIFS_MIN_COMPR_LEN)
  94                 goto no_compr;
  95
  96         if (compr->comp_mutex)
  97                 mutex_lock(compr->comp_mutex);
  98         err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
  99                                    (unsigned int *)out_len);
 100         if (compr->comp_mutex)
 101                 mutex_unlock(compr->comp_mutex);
 102         if (unlikely(err)) {
 103                 ubifs_warn(c, "cannot compress %d bytes, compressor %s, error %d, leave data uncompressed",
 104                            in_len, compr->name, err);
 105                 goto no_compr;
 106         }
 107
 108         /*
 109          * If the data compressed only slightly, it is better to leave it
 110          * uncompressed to improve read speed.
 111          */
 112         if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF)
 113                 goto no_compr;
 114
 115         return;
 116
 117 no_compr:
 118         memcpy(out_buf, in_buf, in_len);
 119         *out_len = in_len;
 120         *compr_type = UBIFS_COMPR_NONE;
 121 }
 122
 123 /**
 124  * ubifs_decompress - decompress data.
 125  * @in_buf: data to decompress
 126  * @in_len: length of the data to decompress
 127  * @out_buf: output buffer where decompressed data should
 128  * @out_len: output length is returned here
 129  * @compr_type: type of compression
 130  *
 131  * This function decompresses data from buffer @in_buf into buffer @out_buf.
 132  * The length of the uncompressed data is returned in @out_len. This functions
 133  * returns %0 on success or a negative error code on failure.
 134  */
 135 int ubifs_decompress(const struct ubifs_info *c, const void *in_buf,
 136                      int in_len, void *out_buf, int *out_len, int compr_type)
 137 {
 138         int err;
 139         struct ubifs_compressor *compr;
 140
 141         if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
 142                 ubifs_err(c, "invalid compression type %d", compr_type);
 143                 return -EINVAL;
 144         }
 145
 146         compr = ubifs_compressors[compr_type];
 147
 148         if (unlikely(!compr->capi_name)) {
 149                 ubifs_err(c, "%s compression is not compiled in", compr->name);
 150                 return -EINVAL;
 151         }
 152
 153         if (compr_type == UBIFS_COMPR_NONE) {
 154                 memcpy(out_buf, in_buf, in_len);
 155                 *out_len = in_len;
 156                 return 0;
 157         }
 158
 159         if (compr->decomp_mutex)
 160                 mutex_lock(compr->decomp_mutex);
 161         err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
 162                                      (unsigned int *)out_len);
 163         if (compr->decomp_mutex)
 164                 mutex_unlock(compr->decomp_mutex);
 165         if (err)
 166                 ubifs_err(c, "cannot decompress %d bytes, compressor %s, error %d",
 167                           in_len, compr->name, err);
 168
 169         return err;
 170 }
 171
 172 /**
 173  * compr_init - initialize a compressor.
 174  * @compr: compressor description object
 175  *
 176  * This function initializes the requested compressor and returns zero in case
 177  * of success or a negative error code in case of failure.
 178  */
 179 static int __init compr_init(struct ubifs_compressor *compr)
 180 {
 181         if (compr->capi_name) {
 182                 compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
 183                 if (IS_ERR(compr->cc)) {
 184                         pr_err("UBIFS error (pid %d): cannot initialize compressor %s, error %ld",
 185                                current->pid, compr->name, PTR_ERR(compr->cc));
 186                         return PTR_ERR(compr->cc);
 187                 }
 188         }
 189
 190         ubifs_compressors[compr->compr_type] = compr;
 191         return 0;
 192 }
 193
 194 /**
 195  * compr_exit - de-initialize a compressor.
 196  * @compr: compressor description object
 197  */
 198 static void compr_exit(struct ubifs_compressor *compr)
 199 {
 200         if (compr->capi_name)
 201                 crypto_free_comp(compr->cc);
 202         return;
 203 }
 204
 205 /**
 206  * ubifs_compressors_init - initialize UBIFS compressors.
 207  *
 208  * This function initializes the compressor which were compiled in. Returns
 209  * zero in case of success and a negative error code in case of failure.
 210  */
 211 int __init ubifs_compressors_init(void)
 212 {
 213         int err;
 214
 215         err = compr_init(&lzo_compr);
 216         if (err)
 217                 return err;
 218
 219         err = compr_init(&zlib_compr);
 220         if (err)
 221                 goto out_lzo;
 222
 223         ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
 224         return 0;
 225
 226 out_lzo:
 227         compr_exit(&lzo_compr);
 228         return err;
 229 }
 230
 231 /**
 232  * ubifs_compressors_exit - de-initialize UBIFS compressors.
 233  */
 234 void ubifs_compressors_exit(void)
 235 {
 236         compr_exit(&lzo_compr);
 237         compr_exit(&zlib_compr);
 238 }