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 #ifdef CONFIG_UBIFS_FS_ZLIB
57 static DEFINE_MUTEX(deflate_mutex);
58 static DEFINE_MUTEX(inflate_mutex);
59 
60 static struct ubifs_compressor zlib_compr = {
61 	.compr_type = UBIFS_COMPR_ZLIB,
62 	.comp_mutex = &deflate_mutex,
63 	.decomp_mutex = &inflate_mutex,
64 	.name = "zlib",
65 	.capi_name = "deflate",
66 };
67 #else
68 static struct ubifs_compressor zlib_compr = {
69 	.compr_type = UBIFS_COMPR_ZLIB,
70 	.name = "zlib",
71 };
72 #endif
73 
74 /* All UBIFS compressors */
75 struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
76 
77 /**
78  * ubifs_compress - compress data.
79  * @in_buf: data to compress
80  * @in_len: length of the data to compress
81  * @out_buf: output buffer where compressed data should be stored
82  * @out_len: output buffer length is returned here
83  * @compr_type: type of compression to use on enter, actually used compression
84  *              type on exit
85  *
86  * This function compresses input buffer @in_buf of length @in_len and stores
87  * the result in the output buffer @out_buf and the resulting length in
88  * @out_len. If the input buffer does not compress, it is just copied to the
89  * @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
90  * compression error occurred.
91  *
92  * Note, if the input buffer was not compressed, it is copied to the output
93  * buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
94  */
ubifs_compress(const void * in_buf,int in_len,void * out_buf,int * out_len,int * compr_type)95 void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len,
96 		    int *compr_type)
97 {
98 	int err;
99 	struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
100 
101 	if (*compr_type == UBIFS_COMPR_NONE)
102 		goto no_compr;
103 
104 	/* If the input data is small, do not even try to compress it */
105 	if (in_len < UBIFS_MIN_COMPR_LEN)
106 		goto no_compr;
107 
108 	if (compr->comp_mutex)
109 		mutex_lock(compr->comp_mutex);
110 	err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
111 				   (unsigned int *)out_len);
112 	if (compr->comp_mutex)
113 		mutex_unlock(compr->comp_mutex);
114 	if (unlikely(err)) {
115 		ubifs_warn("cannot compress %d bytes, compressor %s, "
116 			   "error %d, leave data uncompressed",
117 			   in_len, compr->name, err);
118 		 goto no_compr;
119 	}
120 
121 	/*
122 	 * If the data compressed only slightly, it is better to leave it
123 	 * uncompressed to improve read speed.
124 	 */
125 	if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF)
126 		goto no_compr;
127 
128 	return;
129 
130 no_compr:
131 	memcpy(out_buf, in_buf, in_len);
132 	*out_len = in_len;
133 	*compr_type = UBIFS_COMPR_NONE;
134 }
135 
136 /**
137  * ubifs_decompress - decompress data.
138  * @in_buf: data to decompress
139  * @in_len: length of the data to decompress
140  * @out_buf: output buffer where decompressed data should
141  * @out_len: output length is returned here
142  * @compr_type: type of compression
143  *
144  * This function decompresses data from buffer @in_buf into buffer @out_buf.
145  * The length of the uncompressed data is returned in @out_len. This functions
146  * returns %0 on success or a negative error code on failure.
147  */
ubifs_decompress(const void * in_buf,int in_len,void * out_buf,int * out_len,int compr_type)148 int ubifs_decompress(const void *in_buf, int in_len, void *out_buf,
149 		     int *out_len, int compr_type)
150 {
151 	int err;
152 	struct ubifs_compressor *compr;
153 
154 	if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
155 		ubifs_err("invalid compression type %d", compr_type);
156 		return -EINVAL;
157 	}
158 
159 	compr = ubifs_compressors[compr_type];
160 
161 	if (unlikely(!compr->capi_name)) {
162 		ubifs_err("%s compression is not compiled in", compr->name);
163 		return -EINVAL;
164 	}
165 
166 	if (compr_type == UBIFS_COMPR_NONE) {
167 		memcpy(out_buf, in_buf, in_len);
168 		*out_len = in_len;
169 		return 0;
170 	}
171 
172 	if (compr->decomp_mutex)
173 		mutex_lock(compr->decomp_mutex);
174 	err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
175 				     (unsigned int *)out_len);
176 	if (compr->decomp_mutex)
177 		mutex_unlock(compr->decomp_mutex);
178 	if (err)
179 		ubifs_err("cannot decompress %d bytes, compressor %s, "
180 			  "error %d", in_len, compr->name, err);
181 
182 	return err;
183 }
184 
185 /**
186  * compr_init - initialize a compressor.
187  * @compr: compressor description object
188  *
189  * This function initializes the requested compressor and returns zero in case
190  * of success or a negative error code in case of failure.
191  */
compr_init(struct ubifs_compressor * compr)192 static int __init compr_init(struct ubifs_compressor *compr)
193 {
194 	if (compr->capi_name) {
195 		compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
196 		if (IS_ERR(compr->cc)) {
197 			ubifs_err("cannot initialize compressor %s, error %ld",
198 				  compr->name, PTR_ERR(compr->cc));
199 			return PTR_ERR(compr->cc);
200 		}
201 	}
202 
203 	ubifs_compressors[compr->compr_type] = compr;
204 	return 0;
205 }
206 
207 /**
208  * compr_exit - de-initialize a compressor.
209  * @compr: compressor description object
210  */
compr_exit(struct ubifs_compressor * compr)211 static void compr_exit(struct ubifs_compressor *compr)
212 {
213 	if (compr->capi_name)
214 		crypto_free_comp(compr->cc);
215 	return;
216 }
217 
218 /**
219  * ubifs_compressors_init - initialize UBIFS compressors.
220  *
221  * This function initializes the compressor which were compiled in. Returns
222  * zero in case of success and a negative error code in case of failure.
223  */
ubifs_compressors_init(void)224 int __init ubifs_compressors_init(void)
225 {
226 	int err;
227 
228 	err = compr_init(&lzo_compr);
229 	if (err)
230 		return err;
231 
232 	err = compr_init(&zlib_compr);
233 	if (err)
234 		goto out_lzo;
235 
236 	ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
237 	return 0;
238 
239 out_lzo:
240 	compr_exit(&lzo_compr);
241 	return err;
242 }
243 
244 /**
245  * ubifs_compressors_exit - de-initialize UBIFS compressors.
246  */
ubifs_compressors_exit(void)247 void ubifs_compressors_exit(void)
248 {
249 	compr_exit(&lzo_compr);
250 	compr_exit(&zlib_compr);
251 }
252