1 /*
2 * unix_io.c --- This is the Unix (well, really POSIX) implementation
3 * of the I/O manager.
4 *
5 * Implements a one-block write-through cache.
6 *
7 * Includes support for Windows NT support under Cygwin.
8 *
9 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
10 * 2002 by Theodore Ts'o.
11 *
12 * %Begin-Header%
13 * This file may be redistributed under the terms of the GNU Library
14 * General Public License, version 2.
15 * %End-Header%
16 */
17
18 #define _LARGEFILE_SOURCE
19 #define _LARGEFILE64_SOURCE
20 #ifndef _GNU_SOURCE
21 #define _GNU_SOURCE
22 #endif
23
24 #include <stdio.h>
25 #include <string.h>
26 #if HAVE_UNISTD_H
27 #include <unistd.h>
28 #endif
29 #if HAVE_ERRNO_H
30 #include <errno.h>
31 #endif
32 #include <fcntl.h>
33 #include <time.h>
34 #ifdef __linux__
35 #include <sys/utsname.h>
36 #endif
37 #ifdef HAVE_SYS_IOCTL_H
38 #include <sys/ioctl.h>
39 #endif
40 #ifdef HAVE_SYS_MOUNT_H
41 #include <sys/mount.h>
42 #endif
43 #if HAVE_SYS_STAT_H
44 #include <sys/stat.h>
45 #endif
46 #if HAVE_SYS_TYPES_H
47 #include <sys/types.h>
48 #endif
49 #if HAVE_SYS_RESOURCE_H
50 #include <sys/resource.h>
51 #endif
52 #if HAVE_LINUX_FALLOC_H
53 #include <linux/falloc.h>
54 #endif
55
56 #if defined(__linux__) && defined(_IO) && !defined(BLKROGET)
57 #define BLKROGET _IO(0x12, 94) /* Get read-only status (0 = read_write). */
58 #endif
59
60 #undef ALIGN_DEBUG
61
62 #include "ext2_fs.h"
63 #include "ext2fs.h"
64
65 /*
66 * For checking structure magic numbers...
67 */
68
69 #define EXT2_CHECK_MAGIC(struct, code) \
70 if ((struct)->magic != (code)) return (code)
71
72 struct unix_cache {
73 char *buf;
74 unsigned long long block;
75 int access_time;
76 unsigned dirty:1;
77 unsigned in_use:1;
78 };
79
80 #define CACHE_SIZE 8
81 #define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */
82 #define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */
83
84 struct unix_private_data {
85 int magic;
86 int dev;
87 int flags;
88 int align;
89 int access_time;
90 ext2_loff_t offset;
91 struct unix_cache cache[CACHE_SIZE];
92 void *bounce;
93 struct struct_io_stats io_stats;
94 };
95
96 #define IS_ALIGNED(n, align) ((((unsigned long) n) & \
97 ((unsigned long) ((align)-1))) == 0)
98
99 static errcode_t unix_open(const char *name, int flags, io_channel *channel);
100 static errcode_t unix_close(io_channel channel);
101 static errcode_t unix_set_blksize(io_channel channel, int blksize);
102 static errcode_t unix_read_blk(io_channel channel, unsigned long block,
103 int count, void *data);
104 static errcode_t unix_write_blk(io_channel channel, unsigned long block,
105 int count, const void *data);
106 static errcode_t unix_flush(io_channel channel);
107 static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
108 int size, const void *data);
109 static errcode_t unix_set_option(io_channel channel, const char *option,
110 const char *arg);
111 static errcode_t unix_get_stats(io_channel channel, io_stats *stats)
112 ;
113 static void reuse_cache(io_channel channel, struct unix_private_data *data,
114 struct unix_cache *cache, unsigned long long block);
115 static errcode_t unix_read_blk64(io_channel channel, unsigned long long block,
116 int count, void *data);
117 static errcode_t unix_write_blk64(io_channel channel, unsigned long long block,
118 int count, const void *data);
119 static errcode_t unix_discard(io_channel channel, unsigned long long block,
120 unsigned long long count);
121
122 static struct struct_io_manager struct_unix_manager = {
123 EXT2_ET_MAGIC_IO_MANAGER,
124 "Unix I/O Manager",
125 unix_open,
126 unix_close,
127 unix_set_blksize,
128 unix_read_blk,
129 unix_write_blk,
130 unix_flush,
131 unix_write_byte,
132 unix_set_option,
133 unix_get_stats,
134 unix_read_blk64,
135 unix_write_blk64,
136 unix_discard,
137 };
138
139 io_manager unix_io_manager = &struct_unix_manager;
140
unix_get_stats(io_channel channel,io_stats * stats)141 static errcode_t unix_get_stats(io_channel channel, io_stats *stats)
142 {
143 errcode_t retval = 0;
144
145 struct unix_private_data *data;
146
147 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
148 data = (struct unix_private_data *) channel->private_data;
149 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
150
151 if (stats)
152 *stats = &data->io_stats;
153
154 return retval;
155 }
156
157 /*
158 * Here are the raw I/O functions
159 */
raw_read_blk(io_channel channel,struct unix_private_data * data,unsigned long long block,int count,void * bufv)160 static errcode_t raw_read_blk(io_channel channel,
161 struct unix_private_data *data,
162 unsigned long long block,
163 int count, void *bufv)
164 {
165 errcode_t retval;
166 ssize_t size;
167 ext2_loff_t location;
168 int actual = 0;
169 unsigned char *buf = bufv;
170
171 size = (count < 0) ? -count : count * channel->block_size;
172 data->io_stats.bytes_read += size;
173 location = ((ext2_loff_t) block * channel->block_size) + data->offset;
174 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
175 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
176 goto error_out;
177 }
178 if ((channel->align == 0) ||
179 (IS_ALIGNED(buf, channel->align) &&
180 IS_ALIGNED(size, channel->align))) {
181 actual = read(data->dev, buf, size);
182 if (actual != size) {
183 short_read:
184 if (actual < 0)
185 actual = 0;
186 retval = EXT2_ET_SHORT_READ;
187 goto error_out;
188 }
189 return 0;
190 }
191
192 #ifdef ALIGN_DEBUG
193 printf("raw_read_blk: O_DIRECT fallback: %p %lu\n", buf,
194 (unsigned long) size);
195 #endif
196
197 /*
198 * The buffer or size which we're trying to read isn't aligned
199 * to the O_DIRECT rules, so we need to do this the hard way...
200 */
201 while (size > 0) {
202 actual = read(data->dev, data->bounce, channel->block_size);
203 if (actual != channel->block_size)
204 goto short_read;
205 actual = size;
206 if (size > channel->block_size)
207 actual = channel->block_size;
208 memcpy(buf, data->bounce, actual);
209 size -= actual;
210 buf += actual;
211 }
212 return 0;
213
214 error_out:
215 memset((char *) buf+actual, 0, size-actual);
216 if (channel->read_error)
217 retval = (channel->read_error)(channel, block, count, buf,
218 size, actual, retval);
219 return retval;
220 }
221
raw_write_blk(io_channel channel,struct unix_private_data * data,unsigned long long block,int count,const void * bufv)222 static errcode_t raw_write_blk(io_channel channel,
223 struct unix_private_data *data,
224 unsigned long long block,
225 int count, const void *bufv)
226 {
227 ssize_t size;
228 ext2_loff_t location;
229 int actual = 0;
230 errcode_t retval;
231 const unsigned char *buf = bufv;
232
233 if (count == 1)
234 size = channel->block_size;
235 else {
236 if (count < 0)
237 size = -count;
238 else
239 size = count * channel->block_size;
240 }
241 data->io_stats.bytes_written += size;
242
243 location = ((ext2_loff_t) block * channel->block_size) + data->offset;
244 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
245 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
246 goto error_out;
247 }
248
249 if ((channel->align == 0) ||
250 (IS_ALIGNED(buf, channel->align) &&
251 IS_ALIGNED(size, channel->align))) {
252 actual = write(data->dev, buf, size);
253 if (actual != size) {
254 short_write:
255 retval = EXT2_ET_SHORT_WRITE;
256 goto error_out;
257 }
258 return 0;
259 }
260
261 #ifdef ALIGN_DEBUG
262 printf("raw_write_blk: O_DIRECT fallback: %p %lu\n", buf,
263 (unsigned long) size);
264 #endif
265 /*
266 * The buffer or size which we're trying to write isn't aligned
267 * to the O_DIRECT rules, so we need to do this the hard way...
268 */
269 while (size > 0) {
270 if (size < channel->block_size) {
271 actual = read(data->dev, data->bounce,
272 channel->block_size);
273 if (actual != channel->block_size) {
274 retval = EXT2_ET_SHORT_READ;
275 goto error_out;
276 }
277 }
278 actual = size;
279 if (size > channel->block_size)
280 actual = channel->block_size;
281 memcpy(data->bounce, buf, actual);
282 actual = write(data->dev, data->bounce, channel->block_size);
283 if (actual != channel->block_size)
284 goto short_write;
285 size -= actual;
286 buf += actual;
287 }
288 return 0;
289
290 error_out:
291 if (channel->write_error)
292 retval = (channel->write_error)(channel, block, count, buf,
293 size, actual, retval);
294 return retval;
295 }
296
297
298 /*
299 * Here we implement the cache functions
300 */
301
302 /* Allocate the cache buffers */
alloc_cache(io_channel channel,struct unix_private_data * data)303 static errcode_t alloc_cache(io_channel channel,
304 struct unix_private_data *data)
305 {
306 errcode_t retval;
307 struct unix_cache *cache;
308 int i;
309
310 data->access_time = 0;
311 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
312 cache->block = 0;
313 cache->access_time = 0;
314 cache->dirty = 0;
315 cache->in_use = 0;
316 if (cache->buf)
317 ext2fs_free_mem(&cache->buf);
318 retval = io_channel_alloc_buf(channel, 0, &cache->buf);
319 if (retval)
320 return retval;
321 }
322 if (channel->align) {
323 if (data->bounce)
324 ext2fs_free_mem(&data->bounce);
325 retval = io_channel_alloc_buf(channel, 0, &data->bounce);
326 }
327 return retval;
328 }
329
330 /* Free the cache buffers */
free_cache(struct unix_private_data * data)331 static void free_cache(struct unix_private_data *data)
332 {
333 struct unix_cache *cache;
334 int i;
335
336 data->access_time = 0;
337 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
338 cache->block = 0;
339 cache->access_time = 0;
340 cache->dirty = 0;
341 cache->in_use = 0;
342 if (cache->buf)
343 ext2fs_free_mem(&cache->buf);
344 }
345 if (data->bounce)
346 ext2fs_free_mem(&data->bounce);
347 }
348
349 #ifndef NO_IO_CACHE
350 /*
351 * Try to find a block in the cache. If the block is not found, and
352 * eldest is a non-zero pointer, then fill in eldest with the cache
353 * entry to that should be reused.
354 */
find_cached_block(struct unix_private_data * data,unsigned long long block,struct unix_cache ** eldest)355 static struct unix_cache *find_cached_block(struct unix_private_data *data,
356 unsigned long long block,
357 struct unix_cache **eldest)
358 {
359 struct unix_cache *cache, *unused_cache, *oldest_cache;
360 int i;
361
362 unused_cache = oldest_cache = 0;
363 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
364 if (!cache->in_use) {
365 if (!unused_cache)
366 unused_cache = cache;
367 continue;
368 }
369 if (cache->block == block) {
370 cache->access_time = ++data->access_time;
371 return cache;
372 }
373 if (!oldest_cache ||
374 (cache->access_time < oldest_cache->access_time))
375 oldest_cache = cache;
376 }
377 if (eldest)
378 *eldest = (unused_cache) ? unused_cache : oldest_cache;
379 return 0;
380 }
381
382 /*
383 * Reuse a particular cache entry for another block.
384 */
reuse_cache(io_channel channel,struct unix_private_data * data,struct unix_cache * cache,unsigned long long block)385 static void reuse_cache(io_channel channel, struct unix_private_data *data,
386 struct unix_cache *cache, unsigned long long block)
387 {
388 if (cache->dirty && cache->in_use)
389 raw_write_blk(channel, data, cache->block, 1, cache->buf);
390
391 cache->in_use = 1;
392 cache->dirty = 0;
393 cache->block = block;
394 cache->access_time = ++data->access_time;
395 }
396
397 /*
398 * Flush all of the blocks in the cache
399 */
flush_cached_blocks(io_channel channel,struct unix_private_data * data,int invalidate)400 static errcode_t flush_cached_blocks(io_channel channel,
401 struct unix_private_data *data,
402 int invalidate)
403
404 {
405 struct unix_cache *cache;
406 errcode_t retval, retval2;
407 int i;
408
409 retval2 = 0;
410 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
411 if (!cache->in_use)
412 continue;
413
414 if (invalidate)
415 cache->in_use = 0;
416
417 if (!cache->dirty)
418 continue;
419
420 retval = raw_write_blk(channel, data,
421 cache->block, 1, cache->buf);
422 if (retval)
423 retval2 = retval;
424 else
425 cache->dirty = 0;
426 }
427 return retval2;
428 }
429 #endif /* NO_IO_CACHE */
430
431 #ifdef __linux__
432 #ifndef BLKDISCARDZEROES
433 #define BLKDISCARDZEROES _IO(0x12,124)
434 #endif
435 #endif
436
ext2fs_open_file(const char * pathname,int flags,mode_t mode)437 int ext2fs_open_file(const char *pathname, int flags, mode_t mode)
438 {
439 if (mode)
440 #if defined(HAVE_OPEN64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
441 return open64(pathname, flags, mode);
442 else
443 return open64(pathname, flags);
444 #else
445 return open(pathname, flags, mode);
446 else
447 return open(pathname, flags);
448 #endif
449 }
450
ext2fs_stat(const char * path,ext2fs_struct_stat * buf)451 int ext2fs_stat(const char *path, ext2fs_struct_stat *buf)
452 {
453 #if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
454 return stat64(path, buf);
455 #else
456 return stat(path, buf);
457 #endif
458 }
459
ext2fs_fstat(int fd,ext2fs_struct_stat * buf)460 int ext2fs_fstat(int fd, ext2fs_struct_stat *buf)
461 {
462 #if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
463 return fstat64(fd, buf);
464 #else
465 return fstat(fd, buf);
466 #endif
467 }
468
unix_open(const char * name,int flags,io_channel * channel)469 static errcode_t unix_open(const char *name, int flags, io_channel *channel)
470 {
471 io_channel io = NULL;
472 struct unix_private_data *data = NULL;
473 errcode_t retval;
474 int open_flags;
475 int f_nocache = 0;
476 ext2fs_struct_stat st;
477 #ifdef __linux__
478 struct utsname ut;
479 #endif
480
481 if (name == 0)
482 return EXT2_ET_BAD_DEVICE_NAME;
483 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
484 if (retval)
485 goto cleanup;
486 memset(io, 0, sizeof(struct struct_io_channel));
487 io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
488 retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data);
489 if (retval)
490 goto cleanup;
491
492 io->manager = unix_io_manager;
493 retval = ext2fs_get_mem(strlen(name)+1, &io->name);
494 if (retval)
495 goto cleanup;
496
497 strcpy(io->name, name);
498 io->private_data = data;
499 io->block_size = 1024;
500 io->read_error = 0;
501 io->write_error = 0;
502 io->refcount = 1;
503
504 memset(data, 0, sizeof(struct unix_private_data));
505 data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
506 data->io_stats.num_fields = 2;
507 data->dev = -1;
508
509 open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
510 if (flags & IO_FLAG_EXCLUSIVE)
511 open_flags |= O_EXCL;
512 #if defined(O_DIRECT)
513 if (flags & IO_FLAG_DIRECT_IO) {
514 open_flags |= O_DIRECT;
515 io->align = ext2fs_get_dio_alignment(data->dev);
516 }
517 #elif defined(F_NOCACHE)
518 if (flags & IO_FLAG_DIRECT_IO) {
519 f_nocache = F_NOCACHE;
520 io->align = 4096;
521 }
522 #endif
523 data->flags = flags;
524
525 data->dev = ext2fs_open_file(io->name, open_flags, 0);
526 if (data->dev < 0) {
527 retval = errno;
528 goto cleanup;
529 }
530 if (f_nocache) {
531 if (fcntl(data->dev, f_nocache, 1) < 0) {
532 retval = errno;
533 goto cleanup;
534 }
535 }
536
537 /*
538 * If the device is really a block device, then set the
539 * appropriate flag, otherwise we can set DISCARD_ZEROES flag
540 * because we are going to use punch hole instead of discard
541 * and if it succeed, subsequent read from sparse area returns
542 * zero.
543 */
544 if (ext2fs_stat(io->name, &st) == 0) {
545 if (S_ISBLK(st.st_mode))
546 io->flags |= CHANNEL_FLAGS_BLOCK_DEVICE;
547 else
548 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
549 }
550
551 #ifdef BLKDISCARDZEROES
552 {
553 int zeroes = 0;
554 if (ioctl(data->dev, BLKDISCARDZEROES, &zeroes) == 0 &&
555 zeroes)
556 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
557 }
558 #endif
559
560 #if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
561 /*
562 * Some operating systems require that the buffers be aligned,
563 * regardless of O_DIRECT
564 */
565 if (!io->align)
566 io->align = 512;
567 #endif
568
569
570 if ((retval = alloc_cache(io, data)))
571 goto cleanup;
572
573 #ifdef BLKROGET
574 if (flags & IO_FLAG_RW) {
575 int error;
576 int readonly = 0;
577
578 /* Is the block device actually writable? */
579 error = ioctl(data->dev, BLKROGET, &readonly);
580 if (!error && readonly) {
581 retval = EPERM;
582 goto cleanup;
583 }
584 }
585 #endif
586
587 #ifdef __linux__
588 #undef RLIM_INFINITY
589 #if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4)))
590 #define RLIM_INFINITY ((unsigned long)(~0UL>>1))
591 #else
592 #define RLIM_INFINITY (~0UL)
593 #endif
594 /*
595 * Work around a bug in 2.4.10-2.4.18 kernels where writes to
596 * block devices are wrongly getting hit by the filesize
597 * limit. This workaround isn't perfect, since it won't work
598 * if glibc wasn't built against 2.2 header files. (Sigh.)
599 *
600 */
601 if ((flags & IO_FLAG_RW) &&
602 (uname(&ut) == 0) &&
603 ((ut.release[0] == '2') && (ut.release[1] == '.') &&
604 (ut.release[2] == '4') && (ut.release[3] == '.') &&
605 (ut.release[4] == '1') && (ut.release[5] >= '0') &&
606 (ut.release[5] < '8')) &&
607 (ext2fs_stat(io->name, &st) == 0) &&
608 (S_ISBLK(st.st_mode))) {
609 struct rlimit rlim;
610
611 rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;
612 setrlimit(RLIMIT_FSIZE, &rlim);
613 getrlimit(RLIMIT_FSIZE, &rlim);
614 if (((unsigned long) rlim.rlim_cur) <
615 ((unsigned long) rlim.rlim_max)) {
616 rlim.rlim_cur = rlim.rlim_max;
617 setrlimit(RLIMIT_FSIZE, &rlim);
618 }
619 }
620 #endif
621 *channel = io;
622 return 0;
623
624 cleanup:
625 if (data) {
626 if (data->dev >= 0)
627 close(data->dev);
628 free_cache(data);
629 ext2fs_free_mem(&data);
630 }
631 if (io) {
632 if (io->name) {
633 ext2fs_free_mem(&io->name);
634 }
635 ext2fs_free_mem(&io);
636 }
637 return retval;
638 }
639
unix_close(io_channel channel)640 static errcode_t unix_close(io_channel channel)
641 {
642 struct unix_private_data *data;
643 errcode_t retval = 0;
644
645 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
646 data = (struct unix_private_data *) channel->private_data;
647 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
648
649 if (--channel->refcount > 0)
650 return 0;
651
652 #ifndef NO_IO_CACHE
653 retval = flush_cached_blocks(channel, data, 0);
654 #endif
655
656 if (close(data->dev) < 0)
657 retval = errno;
658 free_cache(data);
659
660 ext2fs_free_mem(&channel->private_data);
661 if (channel->name)
662 ext2fs_free_mem(&channel->name);
663 ext2fs_free_mem(&channel);
664 return retval;
665 }
666
unix_set_blksize(io_channel channel,int blksize)667 static errcode_t unix_set_blksize(io_channel channel, int blksize)
668 {
669 struct unix_private_data *data;
670 errcode_t retval;
671
672 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
673 data = (struct unix_private_data *) channel->private_data;
674 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
675
676 if (channel->block_size != blksize) {
677 #ifndef NO_IO_CACHE
678 if ((retval = flush_cached_blocks(channel, data, 0)))
679 return retval;
680 #endif
681
682 channel->block_size = blksize;
683 free_cache(data);
684 if ((retval = alloc_cache(channel, data)))
685 return retval;
686 }
687 return 0;
688 }
689
690
unix_read_blk64(io_channel channel,unsigned long long block,int count,void * buf)691 static errcode_t unix_read_blk64(io_channel channel, unsigned long long block,
692 int count, void *buf)
693 {
694 struct unix_private_data *data;
695 struct unix_cache *cache, *reuse[READ_DIRECT_SIZE];
696 errcode_t retval;
697 char *cp;
698 int i, j;
699
700 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
701 data = (struct unix_private_data *) channel->private_data;
702 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
703
704 #ifdef NO_IO_CACHE
705 return raw_read_blk(channel, data, block, count, buf);
706 #else
707 /*
708 * If we're doing an odd-sized read or a very large read,
709 * flush out the cache and then do a direct read.
710 */
711 if (count < 0 || count > WRITE_DIRECT_SIZE) {
712 if ((retval = flush_cached_blocks(channel, data, 0)))
713 return retval;
714 return raw_read_blk(channel, data, block, count, buf);
715 }
716
717 cp = buf;
718 while (count > 0) {
719 /* If it's in the cache, use it! */
720 if ((cache = find_cached_block(data, block, &reuse[0]))) {
721 #ifdef DEBUG
722 printf("Using cached block %lu\n", block);
723 #endif
724 memcpy(cp, cache->buf, channel->block_size);
725 count--;
726 block++;
727 cp += channel->block_size;
728 continue;
729 }
730 if (count == 1) {
731 /*
732 * Special case where we read directly into the
733 * cache buffer; important in the O_DIRECT case
734 */
735 cache = reuse[0];
736 reuse_cache(channel, data, cache, block);
737 if ((retval = raw_read_blk(channel, data, block, 1,
738 cache->buf))) {
739 cache->in_use = 0;
740 return retval;
741 }
742 memcpy(cp, cache->buf, channel->block_size);
743 return 0;
744 }
745
746 /*
747 * Find the number of uncached blocks so we can do a
748 * single read request
749 */
750 for (i=1; i < count; i++)
751 if (find_cached_block(data, block+i, &reuse[i]))
752 break;
753 #ifdef DEBUG
754 printf("Reading %d blocks starting at %lu\n", i, block);
755 #endif
756 if ((retval = raw_read_blk(channel, data, block, i, cp)))
757 return retval;
758
759 /* Save the results in the cache */
760 for (j=0; j < i; j++) {
761 count--;
762 cache = reuse[j];
763 reuse_cache(channel, data, cache, block++);
764 memcpy(cache->buf, cp, channel->block_size);
765 cp += channel->block_size;
766 }
767 }
768 return 0;
769 #endif /* NO_IO_CACHE */
770 }
771
unix_read_blk(io_channel channel,unsigned long block,int count,void * buf)772 static errcode_t unix_read_blk(io_channel channel, unsigned long block,
773 int count, void *buf)
774 {
775 return unix_read_blk64(channel, block, count, buf);
776 }
777
unix_write_blk64(io_channel channel,unsigned long long block,int count,const void * buf)778 static errcode_t unix_write_blk64(io_channel channel, unsigned long long block,
779 int count, const void *buf)
780 {
781 struct unix_private_data *data;
782 struct unix_cache *cache, *reuse;
783 errcode_t retval = 0;
784 const char *cp;
785 int writethrough;
786
787 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
788 data = (struct unix_private_data *) channel->private_data;
789 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
790
791 #ifdef NO_IO_CACHE
792 return raw_write_blk(channel, data, block, count, buf);
793 #else
794 /*
795 * If we're doing an odd-sized write or a very large write,
796 * flush out the cache completely and then do a direct write.
797 */
798 if (count < 0 || count > WRITE_DIRECT_SIZE) {
799 if ((retval = flush_cached_blocks(channel, data, 1)))
800 return retval;
801 return raw_write_blk(channel, data, block, count, buf);
802 }
803
804 /*
805 * For a moderate-sized multi-block write, first force a write
806 * if we're in write-through cache mode, and then fill the
807 * cache with the blocks.
808 */
809 writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH;
810 if (writethrough)
811 retval = raw_write_blk(channel, data, block, count, buf);
812
813 cp = buf;
814 while (count > 0) {
815 cache = find_cached_block(data, block, &reuse);
816 if (!cache) {
817 cache = reuse;
818 reuse_cache(channel, data, cache, block);
819 }
820 memcpy(cache->buf, cp, channel->block_size);
821 cache->dirty = !writethrough;
822 count--;
823 block++;
824 cp += channel->block_size;
825 }
826 return retval;
827 #endif /* NO_IO_CACHE */
828 }
829
unix_write_blk(io_channel channel,unsigned long block,int count,const void * buf)830 static errcode_t unix_write_blk(io_channel channel, unsigned long block,
831 int count, const void *buf)
832 {
833 return unix_write_blk64(channel, block, count, buf);
834 }
835
unix_write_byte(io_channel channel,unsigned long offset,int size,const void * buf)836 static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
837 int size, const void *buf)
838 {
839 struct unix_private_data *data;
840 errcode_t retval = 0;
841 ssize_t actual;
842
843 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
844 data = (struct unix_private_data *) channel->private_data;
845 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
846
847 if (channel->align != 0) {
848 #ifdef ALIGN_DEBUG
849 printf("unix_write_byte: O_DIRECT fallback\n");
850 #endif
851 return EXT2_ET_UNIMPLEMENTED;
852 }
853
854 #ifndef NO_IO_CACHE
855 /*
856 * Flush out the cache completely
857 */
858 if ((retval = flush_cached_blocks(channel, data, 1)))
859 return retval;
860 #endif
861
862 if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0)
863 return errno;
864
865 actual = write(data->dev, buf, size);
866 if (actual != size)
867 return EXT2_ET_SHORT_WRITE;
868
869 return 0;
870 }
871
872 /*
873 * Flush data buffers to disk.
874 */
unix_flush(io_channel channel)875 static errcode_t unix_flush(io_channel channel)
876 {
877 struct unix_private_data *data;
878 errcode_t retval = 0;
879
880 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
881 data = (struct unix_private_data *) channel->private_data;
882 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
883
884 #ifndef NO_IO_CACHE
885 retval = flush_cached_blocks(channel, data, 0);
886 #endif
887 fsync(data->dev);
888 return retval;
889 }
890
unix_set_option(io_channel channel,const char * option,const char * arg)891 static errcode_t unix_set_option(io_channel channel, const char *option,
892 const char *arg)
893 {
894 struct unix_private_data *data;
895 unsigned long long tmp;
896 char *end;
897
898 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
899 data = (struct unix_private_data *) channel->private_data;
900 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
901
902 if (!strcmp(option, "offset")) {
903 if (!arg)
904 return EXT2_ET_INVALID_ARGUMENT;
905
906 tmp = strtoull(arg, &end, 0);
907 if (*end)
908 return EXT2_ET_INVALID_ARGUMENT;
909 data->offset = tmp;
910 if (data->offset < 0)
911 return EXT2_ET_INVALID_ARGUMENT;
912 return 0;
913 }
914 return EXT2_ET_INVALID_ARGUMENT;
915 }
916
917 #if defined(__linux__) && !defined(BLKDISCARD)
918 #define BLKDISCARD _IO(0x12,119)
919 #endif
920
unix_discard(io_channel channel,unsigned long long block,unsigned long long count)921 static errcode_t unix_discard(io_channel channel, unsigned long long block,
922 unsigned long long count)
923 {
924 struct unix_private_data *data;
925 int ret;
926
927 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
928 data = (struct unix_private_data *) channel->private_data;
929 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
930
931 if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) {
932 #ifdef BLKDISCARD
933 __uint64_t range[2];
934
935 range[0] = (__uint64_t)(block) * channel->block_size;
936 range[1] = (__uint64_t)(count) * channel->block_size;
937
938 ret = ioctl(data->dev, BLKDISCARD, &range);
939 #else
940 goto unimplemented;
941 #endif
942 } else {
943 #if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE)
944 /*
945 * If we are not on block device, try to use punch hole
946 * to reclaim free space.
947 */
948 ret = fallocate(data->dev,
949 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
950 (off_t)(block) * channel->block_size,
951 (off_t)(count) * channel->block_size);
952 #else
953 goto unimplemented;
954 #endif
955 }
956 if (ret < 0) {
957 if (errno == EOPNOTSUPP)
958 goto unimplemented;
959 return errno;
960 }
961 return 0;
962 unimplemented:
963 return EXT2_ET_UNIMPLEMENTED;
964 }
965