projects/linux·blob master · refs

426 lines · 11.7 KiB

1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 Red Hat, Inc.
5 * Copyright © 2004-2010 David Woodhouse <[email protected]>
6 * Copyright © 2004 Ferenc Havasi <[email protected]>,
7 * University of Szeged, Hungary
8 *
9 * Created by Arjan van de Ven <[email protected]>
10 *
11 * For licensing information, see the file 'LICENCE' in this directory.
12 *
13 */
14
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include "compr.h"
18
19static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
20
21/* Available compressors are on this list */
22static LIST_HEAD(jffs2_compressor_list);
23
24/* Actual compression mode */
25static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
26
27/* Statistics for blocks stored without compression */
28static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
29
30
31/*
32 * Return 1 to use this compression
33 */
34static int jffs2_is_best_compression(struct jffs2_compressor *this,
35 struct jffs2_compressor *best, uint32_t size, uint32_t bestsize)
36{
37 switch (jffs2_compression_mode) {
38 case JFFS2_COMPR_MODE_SIZE:
39 if (bestsize > size)
40 return 1;
41 return 0;
42 case JFFS2_COMPR_MODE_FAVOURLZO:
43 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size))
44 return 1;
45 if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size))
46 return 1;
47 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100)))
48 return 1;
49 if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size)
50 return 1;
51
52 return 0;
53 }
54 /* Shouldn't happen */
55 return 0;
56}
57
58/*
59 * jffs2_selected_compress:
60 * @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB).
61 * If 0, just take the first available compression mode.
62 * @data_in: Pointer to uncompressed data
63 * @cpage_out: Pointer to returned pointer to buffer for compressed data
64 * @datalen: On entry, holds the amount of data available for compression.
65 * On exit, expected to hold the amount of data actually compressed.
66 * @cdatalen: On entry, holds the amount of space available for compressed
67 * data. On exit, expected to hold the actual size of the compressed
68 * data.
69 *
70 * Returns: the compression type used. Zero is used to show that the data
71 * could not be compressed; probably because we couldn't find the requested
72 * compression mode.
73 */
74static int jffs2_selected_compress(u8 compr, unsigned char *data_in,
75 unsigned char **cpage_out, u32 *datalen, u32 *cdatalen)
76{
77 struct jffs2_compressor *this;
78 int err, ret = JFFS2_COMPR_NONE;
79 uint32_t orig_slen, orig_dlen;
80 char *output_buf;
81
82 output_buf = kmalloc(*cdatalen, GFP_KERNEL);
83 if (!output_buf) {
84 pr_warn("No memory for compressor allocation. Compression failed.\n");
85 return ret;
86 }
87 orig_slen = *datalen;
88 orig_dlen = *cdatalen;
89 spin_lock(&jffs2_compressor_list_lock);
90 list_for_each_entry(this, &jffs2_compressor_list, list) {
91 /* Skip decompress-only and disabled modules */
92 if (!this->compress || this->disabled)
93 continue;
94
95 /* Skip if not the desired compression type */
96 if (compr && (compr != this->compr))
97 continue;
98
99 /*
100 * Either compression type was unspecified, or we found our
101 * compressor; either way, we're good to go.
102 */
103 this->usecount++;
104 spin_unlock(&jffs2_compressor_list_lock);
105
106 *datalen = orig_slen;
107 *cdatalen = orig_dlen;
108 err = this->compress(data_in, output_buf, datalen, cdatalen);
109
110 spin_lock(&jffs2_compressor_list_lock);
111 this->usecount--;
112 if (!err) {
113 /* Success */
114 ret = this->compr;
115 this->stat_compr_blocks++;
116 this->stat_compr_orig_size += *datalen;
117 this->stat_compr_new_size += *cdatalen;
118 break;
119 }
120 }
121 spin_unlock(&jffs2_compressor_list_lock);
122 if (ret == JFFS2_COMPR_NONE)
123 kfree(output_buf);
124 else
125 *cpage_out = output_buf;
126
127 return ret;
128}
129
130/* jffs2_compress:
131 * @data_in: Pointer to uncompressed data
132 * @cpage_out: Pointer to returned pointer to buffer for compressed data
133 * @datalen: On entry, holds the amount of data available for compression.
134 * On exit, expected to hold the amount of data actually compressed.
135 * @cdatalen: On entry, holds the amount of space available for compressed
136 * data. On exit, expected to hold the actual size of the compressed
137 * data.
138 *
139 * Returns: Lower byte to be stored with data indicating compression type used.
140 * Zero is used to show that the data could not be compressed - the
141 * compressed version was actually larger than the original.
142 * Upper byte will be used later. (soon)
143 *
144 * If the cdata buffer isn't large enough to hold all the uncompressed data,
145 * jffs2_compress should compress as much as will fit, and should set
146 * *datalen accordingly to show the amount of data which were compressed.
147 */
148uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
149 unsigned char *data_in, unsigned char **cpage_out,
150 uint32_t *datalen, uint32_t *cdatalen)
151{
152 int ret = JFFS2_COMPR_NONE;
153 int mode, compr_ret;
154 struct jffs2_compressor *this, *best=NULL;
155 unsigned char *output_buf = NULL, *tmp_buf;
156 uint32_t orig_slen, orig_dlen;
157 uint32_t best_slen=0, best_dlen=0;
158
159 if (c->mount_opts.override_compr)
160 mode = c->mount_opts.compr;
161 else
162 mode = jffs2_compression_mode;
163
164 switch (mode) {
165 case JFFS2_COMPR_MODE_NONE:
166 break;
167 case JFFS2_COMPR_MODE_PRIORITY:
168 ret = jffs2_selected_compress(0, data_in, cpage_out, datalen,
169 cdatalen);
170 break;
171 case JFFS2_COMPR_MODE_SIZE:
172 case JFFS2_COMPR_MODE_FAVOURLZO:
173 orig_slen = *datalen;
174 orig_dlen = *cdatalen;
175 spin_lock(&jffs2_compressor_list_lock);
176 list_for_each_entry(this, &jffs2_compressor_list, list) {
177 /* Skip decompress-only backwards-compatibility and disabled modules */
178 if ((!this->compress)||(this->disabled))
179 continue;
180 /* Allocating memory for output buffer if necessary */
181 if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
182 spin_unlock(&jffs2_compressor_list_lock);
183 kfree(this->compr_buf);
184 spin_lock(&jffs2_compressor_list_lock);
185 this->compr_buf_size=0;
186 this->compr_buf=NULL;
187 }
188 if (!this->compr_buf) {
189 spin_unlock(&jffs2_compressor_list_lock);
190 tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
191 spin_lock(&jffs2_compressor_list_lock);
192 if (!tmp_buf) {
193 pr_warn("No memory for compressor allocation. (%d bytes)\n",
194 orig_slen);
195 continue;
196 }
197 else {
198 this->compr_buf = tmp_buf;
199 this->compr_buf_size = orig_slen;
200 }
201 }
202 this->usecount++;
203 spin_unlock(&jffs2_compressor_list_lock);
204 *datalen = orig_slen;
205 *cdatalen = orig_dlen;
206 compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
207 spin_lock(&jffs2_compressor_list_lock);
208 this->usecount--;
209 if (!compr_ret) {
210 if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
211 && (*cdatalen < *datalen)) {
212 best_dlen = *cdatalen;
213 best_slen = *datalen;
214 best = this;
215 }
216 }
217 }
218 if (best_dlen) {
219 *cdatalen = best_dlen;
220 *datalen = best_slen;
221 output_buf = best->compr_buf;
222 best->compr_buf = NULL;
223 best->compr_buf_size = 0;
224 best->stat_compr_blocks++;
225 best->stat_compr_orig_size += best_slen;
226 best->stat_compr_new_size += best_dlen;
227 ret = best->compr;
228 *cpage_out = output_buf;
229 }
230 spin_unlock(&jffs2_compressor_list_lock);
231 break;
232 case JFFS2_COMPR_MODE_FORCELZO:
233 ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in,
234 cpage_out, datalen, cdatalen);
235 break;
236 case JFFS2_COMPR_MODE_FORCEZLIB:
237 ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in,
238 cpage_out, datalen, cdatalen);
239 break;
240 default:
241 pr_err("unknown compression mode\n");
242 }
243
244 if (ret == JFFS2_COMPR_NONE) {
245 *cpage_out = data_in;
246 *datalen = *cdatalen;
247 none_stat_compr_blocks++;
248 none_stat_compr_size += *datalen;
249 }
250 return ret;
251}
252
253int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
254 uint16_t comprtype, unsigned char *cdata_in,
255 unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
256{
257 struct jffs2_compressor *this;
258 int ret;
259
260 /* Older code had a bug where it would write non-zero 'usercompr'
261 fields. Deal with it. */
262 if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
263 comprtype &= 0xff;
264
265 switch (comprtype & 0xff) {
266 case JFFS2_COMPR_NONE:
267 /* This should be special-cased elsewhere, but we might as well deal with it */
268 memcpy(data_out, cdata_in, datalen);
269 none_stat_decompr_blocks++;
270 break;
271 case JFFS2_COMPR_ZERO:
272 memset(data_out, 0, datalen);
273 break;
274 default:
275 spin_lock(&jffs2_compressor_list_lock);
276 list_for_each_entry(this, &jffs2_compressor_list, list) {
277 if (comprtype == this->compr) {
278 this->usecount++;
279 spin_unlock(&jffs2_compressor_list_lock);
280 ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
281 spin_lock(&jffs2_compressor_list_lock);
282 if (ret) {
283 pr_warn("Decompressor \"%s\" returned %d\n",
284 this->name, ret);
285 }
286 else {
287 this->stat_decompr_blocks++;
288 }
289 this->usecount--;
290 spin_unlock(&jffs2_compressor_list_lock);
291 return ret;
292 }
293 }
294 pr_warn("compression type 0x%02x not available\n", comprtype);
295 spin_unlock(&jffs2_compressor_list_lock);
296 return -EIO;
297 }
298 return 0;
299}
300
301int jffs2_register_compressor(struct jffs2_compressor *comp)
302{
303 struct jffs2_compressor *this;
304
305 if (!comp->name) {
306 pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n");
307 return -1;
308 }
309 comp->compr_buf_size=0;
310 comp->compr_buf=NULL;
311 comp->usecount=0;
312 comp->stat_compr_orig_size=0;
313 comp->stat_compr_new_size=0;
314 comp->stat_compr_blocks=0;
315 comp->stat_decompr_blocks=0;
316 jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name);
317
318 spin_lock(&jffs2_compressor_list_lock);
319
320 list_for_each_entry(this, &jffs2_compressor_list, list) {
321 if (this->priority < comp->priority) {
322 list_add(&comp->list, this->list.prev);
323 goto out;
324 }
325 }
326 list_add_tail(&comp->list, &jffs2_compressor_list);
327out:
328 D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
329 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
330 })
331
332 spin_unlock(&jffs2_compressor_list_lock);
333
334 return 0;
335}
336
337int jffs2_unregister_compressor(struct jffs2_compressor *comp)
338{
339 D2(struct jffs2_compressor *this);
340
341 jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name);
342
343 spin_lock(&jffs2_compressor_list_lock);
344
345 if (comp->usecount) {
346 spin_unlock(&jffs2_compressor_list_lock);
347 pr_warn("Compressor module is in use. Unregister failed.\n");
348 return -1;
349 }
350 list_del(&comp->list);
351
352 D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
353 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
354 })
355 spin_unlock(&jffs2_compressor_list_lock);
356 return 0;
357}
358
359void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
360{
361 if (orig != comprbuf)
362 kfree(comprbuf);
363}
364
365int __init jffs2_compressors_init(void)
366{
367 int ret = 0;
368/* Registering compressors */
369 ret = jffs2_zlib_init();
370 if (ret)
371 goto exit;
372 ret = jffs2_rtime_init();
373 if (ret)
374 goto exit_zlib;
375 ret = jffs2_rubinmips_init();
376 if (ret)
377 goto exit_rtime;
378 ret = jffs2_dynrubin_init();
379 if (ret)
380 goto exit_runinmips;
381 ret = jffs2_lzo_init();
382 if (ret)
383 goto exit_dynrubin;
384
385
386/* Setting default compression mode */
387#ifdef CONFIG_JFFS2_CMODE_NONE
388 jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
389 jffs2_dbg(1, "default compression mode: none\n");
390#else
391#ifdef CONFIG_JFFS2_CMODE_SIZE
392 jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
393 jffs2_dbg(1, "default compression mode: size\n");
394#else
395#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
396 jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
397 jffs2_dbg(1, "default compression mode: favourlzo\n");
398#else
399 jffs2_dbg(1, "default compression mode: priority\n");
400#endif
401#endif
402#endif
403 return 0;
404
405exit_dynrubin:
406 jffs2_dynrubin_exit();
407exit_runinmips:
408 jffs2_rubinmips_exit();
409exit_rtime:
410 jffs2_rtime_exit();
411exit_zlib:
412 jffs2_zlib_exit();
413exit:
414 return ret;
415}
416
417int jffs2_compressors_exit(void)
418{
419/* Unregistering compressors */
420 jffs2_lzo_exit();
421 jffs2_dynrubin_exit();
422 jffs2_rubinmips_exit();
423 jffs2_rtime_exit();
424 jffs2_zlib_exit();
425 return 0;
426}