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libext2fs: revert "try to always use PUNCH_HOLE for unix_discard"
[thirdparty/e2fsprogs.git] / lib / ext2fs / unix_io.c
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 #if !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__OpenBSD__)
19 #define _XOPEN_SOURCE 600
20 #define _DARWIN_C_SOURCE
21 #define _FILE_OFFSET_BITS 64
22 #ifndef _LARGEFILE_SOURCE
23 #define _LARGEFILE_SOURCE
24 #endif
25 #ifndef _LARGEFILE64_SOURCE
26 #define _LARGEFILE64_SOURCE
27 #endif
28 #ifndef _GNU_SOURCE
29 #define _GNU_SOURCE
30 #endif
31 #endif
32
33 #include "config.h"
34 #include <stdio.h>
35 #include <string.h>
36 #if HAVE_UNISTD_H
37 #include <unistd.h>
38 #endif
39 #if HAVE_ERRNO_H
40 #include <errno.h>
41 #endif
42 #include <fcntl.h>
43 #include <time.h>
44 #ifdef __linux__
45 #include <sys/utsname.h>
46 #endif
47 #if HAVE_SYS_TYPES_H
48 #include <sys/types.h>
49 #endif
50 #ifdef HAVE_SYS_IOCTL_H
51 #include <sys/ioctl.h>
52 #endif
53 #ifdef HAVE_SYS_MOUNT_H
54 #include <sys/mount.h>
55 #endif
56 #ifdef HAVE_SYS_PRCTL_H
57 #include <sys/prctl.h>
58 #else
59 #define PR_GET_DUMPABLE 3
60 #endif
61 #if HAVE_SYS_STAT_H
62 #include <sys/stat.h>
63 #endif
64 #if HAVE_SYS_RESOURCE_H
65 #include <sys/resource.h>
66 #endif
67 #if HAVE_LINUX_FALLOC_H
68 #include <linux/falloc.h>
69 #endif
70
71 #if defined(__linux__) && defined(_IO) && !defined(BLKROGET)
72 #define BLKROGET _IO(0x12, 94) /* Get read-only status (0 = read_write). */
73 #endif
74
75 #undef ALIGN_DEBUG
76
77 #include "ext2_fs.h"
78 #include "ext2fs.h"
79 #include "ext2fsP.h"
80
81 /*
82 * For checking structure magic numbers...
83 */
84
85 #define EXT2_CHECK_MAGIC(struct, code) \
86 if ((struct)->magic != (code)) return (code)
87
88 struct unix_cache {
89 char *buf;
90 unsigned long long block;
91 int access_time;
92 unsigned dirty:1;
93 unsigned in_use:1;
94 };
95
96 #define CACHE_SIZE 8
97 #define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */
98 #define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */
99
100 struct unix_private_data {
101 int magic;
102 int dev;
103 int flags;
104 int align;
105 int access_time;
106 ext2_loff_t offset;
107 struct unix_cache cache[CACHE_SIZE];
108 void *bounce;
109 struct struct_io_stats io_stats;
110 };
111
112 #define IS_ALIGNED(n, align) ((((uintptr_t) n) & \
113 ((uintptr_t) ((align)-1))) == 0)
114
115 static errcode_t unix_get_stats(io_channel channel, io_stats *stats)
116 {
117 errcode_t retval = 0;
118
119 struct unix_private_data *data;
120
121 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
122 data = (struct unix_private_data *) channel->private_data;
123 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
124
125 if (stats)
126 *stats = &data->io_stats;
127
128 return retval;
129 }
130
131 static char *safe_getenv(const char *arg)
132 {
133 if ((getuid() != geteuid()) || (getgid() != getegid()))
134 return NULL;
135 #ifdef HAVE_PRCTL
136 if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
137 return NULL;
138 #else
139 #if (defined(linux) && defined(SYS_prctl))
140 if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
141 return NULL;
142 #endif
143 #endif
144
145 #if defined(HAVE_SECURE_GETENV)
146 return secure_getenv(arg);
147 #elif defined(HAVE___SECURE_GETENV)
148 return __secure_getenv(arg);
149 #else
150 return getenv(arg);
151 #endif
152 }
153
154 /*
155 * Here are the raw I/O functions
156 */
157 static errcode_t raw_read_blk(io_channel channel,
158 struct unix_private_data *data,
159 unsigned long long block,
160 int count, void *bufv)
161 {
162 errcode_t retval;
163 ssize_t size;
164 ext2_loff_t location;
165 int actual = 0;
166 unsigned char *buf = bufv;
167 ssize_t really_read = 0;
168
169 size = (count < 0) ? -count : count * channel->block_size;
170 data->io_stats.bytes_read += size;
171 location = ((ext2_loff_t) block * channel->block_size) + data->offset;
172
173 if (data->flags & IO_FLAG_FORCE_BOUNCE) {
174 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
175 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
176 goto error_out;
177 }
178 goto bounce_read;
179 }
180
181 #ifdef HAVE_PREAD64
182 /* Try an aligned pread */
183 if ((channel->align == 0) ||
184 (IS_ALIGNED(buf, channel->align) &&
185 IS_ALIGNED(size, channel->align))) {
186 actual = pread64(data->dev, buf, size, location);
187 if (actual == size)
188 return 0;
189 actual = 0;
190 }
191 #elif HAVE_PREAD
192 /* Try an aligned pread */
193 if ((sizeof(off_t) >= sizeof(ext2_loff_t)) &&
194 ((channel->align == 0) ||
195 (IS_ALIGNED(buf, channel->align) &&
196 IS_ALIGNED(size, channel->align)))) {
197 actual = pread(data->dev, buf, size, location);
198 if (actual == size)
199 return 0;
200 actual = 0;
201 }
202 #endif /* HAVE_PREAD */
203
204 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
205 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
206 goto error_out;
207 }
208 if ((channel->align == 0) ||
209 (IS_ALIGNED(buf, channel->align) &&
210 IS_ALIGNED(size, channel->align))) {
211 actual = read(data->dev, buf, size);
212 if (actual != size) {
213 short_read:
214 if (actual < 0) {
215 retval = errno;
216 actual = 0;
217 } else
218 retval = EXT2_ET_SHORT_READ;
219 goto error_out;
220 }
221 return 0;
222 }
223
224 #ifdef ALIGN_DEBUG
225 printf("raw_read_blk: O_DIRECT fallback: %p %lu\n", buf,
226 (unsigned long) size);
227 #endif
228
229 /*
230 * The buffer or size which we're trying to read isn't aligned
231 * to the O_DIRECT rules, so we need to do this the hard way...
232 */
233 bounce_read:
234 while (size > 0) {
235 actual = read(data->dev, data->bounce, channel->block_size);
236 if (actual != channel->block_size) {
237 actual = really_read;
238 buf -= really_read;
239 size += really_read;
240 goto short_read;
241 }
242 actual = size;
243 if (size > channel->block_size)
244 actual = channel->block_size;
245 memcpy(buf, data->bounce, actual);
246 really_read += actual;
247 size -= actual;
248 buf += actual;
249 }
250 return 0;
251
252 error_out:
253 if (actual >= 0 && actual < size)
254 memset((char *) buf+actual, 0, size-actual);
255 if (channel->read_error)
256 retval = (channel->read_error)(channel, block, count, buf,
257 size, actual, retval);
258 return retval;
259 }
260
261 static errcode_t raw_write_blk(io_channel channel,
262 struct unix_private_data *data,
263 unsigned long long block,
264 int count, const void *bufv)
265 {
266 ssize_t size;
267 ext2_loff_t location;
268 int actual = 0;
269 errcode_t retval;
270 const unsigned char *buf = bufv;
271
272 if (count == 1)
273 size = channel->block_size;
274 else {
275 if (count < 0)
276 size = -count;
277 else
278 size = count * channel->block_size;
279 }
280 data->io_stats.bytes_written += size;
281
282 location = ((ext2_loff_t) block * channel->block_size) + data->offset;
283
284 if (data->flags & IO_FLAG_FORCE_BOUNCE) {
285 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
286 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
287 goto error_out;
288 }
289 goto bounce_write;
290 }
291
292 #ifdef HAVE_PWRITE64
293 /* Try an aligned pwrite */
294 if ((channel->align == 0) ||
295 (IS_ALIGNED(buf, channel->align) &&
296 IS_ALIGNED(size, channel->align))) {
297 actual = pwrite64(data->dev, buf, size, location);
298 if (actual == size)
299 return 0;
300 }
301 #elif HAVE_PWRITE
302 /* Try an aligned pwrite */
303 if ((sizeof(off_t) >= sizeof(ext2_loff_t)) &&
304 ((channel->align == 0) ||
305 (IS_ALIGNED(buf, channel->align) &&
306 IS_ALIGNED(size, channel->align)))) {
307 actual = pwrite(data->dev, buf, size, location);
308 if (actual == size)
309 return 0;
310 }
311 #endif /* HAVE_PWRITE */
312
313 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
314 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
315 goto error_out;
316 }
317
318 if ((channel->align == 0) ||
319 (IS_ALIGNED(buf, channel->align) &&
320 IS_ALIGNED(size, channel->align))) {
321 actual = write(data->dev, buf, size);
322 if (actual < 0) {
323 retval = errno;
324 goto error_out;
325 }
326 if (actual != size) {
327 short_write:
328 retval = EXT2_ET_SHORT_WRITE;
329 goto error_out;
330 }
331 return 0;
332 }
333
334 #ifdef ALIGN_DEBUG
335 printf("raw_write_blk: O_DIRECT fallback: %p %lu\n", buf,
336 (unsigned long) size);
337 #endif
338 /*
339 * The buffer or size which we're trying to write isn't aligned
340 * to the O_DIRECT rules, so we need to do this the hard way...
341 */
342 bounce_write:
343 while (size > 0) {
344 if (size < channel->block_size) {
345 actual = read(data->dev, data->bounce,
346 channel->block_size);
347 if (actual != channel->block_size) {
348 if (actual < 0) {
349 retval = errno;
350 goto error_out;
351 }
352 memset((char *) data->bounce + actual, 0,
353 channel->block_size - actual);
354 }
355 }
356 actual = size;
357 if (size > channel->block_size)
358 actual = channel->block_size;
359 memcpy(data->bounce, buf, actual);
360 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
361 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
362 goto error_out;
363 }
364 actual = write(data->dev, data->bounce, channel->block_size);
365 if (actual < 0) {
366 retval = errno;
367 goto error_out;
368 }
369 if (actual != channel->block_size)
370 goto short_write;
371 size -= actual;
372 buf += actual;
373 location += actual;
374 }
375 return 0;
376
377 error_out:
378 if (channel->write_error)
379 retval = (channel->write_error)(channel, block, count, buf,
380 size, actual, retval);
381 return retval;
382 }
383
384
385 /*
386 * Here we implement the cache functions
387 */
388
389 /* Allocate the cache buffers */
390 static errcode_t alloc_cache(io_channel channel,
391 struct unix_private_data *data)
392 {
393 errcode_t retval;
394 struct unix_cache *cache;
395 int i;
396
397 data->access_time = 0;
398 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
399 cache->block = 0;
400 cache->access_time = 0;
401 cache->dirty = 0;
402 cache->in_use = 0;
403 if (cache->buf)
404 ext2fs_free_mem(&cache->buf);
405 retval = io_channel_alloc_buf(channel, 0, &cache->buf);
406 if (retval)
407 return retval;
408 }
409 if (channel->align || data->flags & IO_FLAG_FORCE_BOUNCE) {
410 if (data->bounce)
411 ext2fs_free_mem(&data->bounce);
412 retval = io_channel_alloc_buf(channel, 0, &data->bounce);
413 }
414 return retval;
415 }
416
417 /* Free the cache buffers */
418 static void free_cache(struct unix_private_data *data)
419 {
420 struct unix_cache *cache;
421 int i;
422
423 data->access_time = 0;
424 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
425 cache->block = 0;
426 cache->access_time = 0;
427 cache->dirty = 0;
428 cache->in_use = 0;
429 if (cache->buf)
430 ext2fs_free_mem(&cache->buf);
431 }
432 if (data->bounce)
433 ext2fs_free_mem(&data->bounce);
434 }
435
436 #ifndef NO_IO_CACHE
437 /*
438 * Try to find a block in the cache. If the block is not found, and
439 * eldest is a non-zero pointer, then fill in eldest with the cache
440 * entry to that should be reused.
441 */
442 static struct unix_cache *find_cached_block(struct unix_private_data *data,
443 unsigned long long block,
444 struct unix_cache **eldest)
445 {
446 struct unix_cache *cache, *unused_cache, *oldest_cache;
447 int i;
448
449 unused_cache = oldest_cache = 0;
450 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
451 if (!cache->in_use) {
452 if (!unused_cache)
453 unused_cache = cache;
454 continue;
455 }
456 if (cache->block == block) {
457 cache->access_time = ++data->access_time;
458 return cache;
459 }
460 if (!oldest_cache ||
461 (cache->access_time < oldest_cache->access_time))
462 oldest_cache = cache;
463 }
464 if (eldest)
465 *eldest = (unused_cache) ? unused_cache : oldest_cache;
466 return 0;
467 }
468
469 /*
470 * Reuse a particular cache entry for another block.
471 */
472 static void reuse_cache(io_channel channel, struct unix_private_data *data,
473 struct unix_cache *cache, unsigned long long block)
474 {
475 if (cache->dirty && cache->in_use)
476 raw_write_blk(channel, data, cache->block, 1, cache->buf);
477
478 cache->in_use = 1;
479 cache->dirty = 0;
480 cache->block = block;
481 cache->access_time = ++data->access_time;
482 }
483
484 /*
485 * Flush all of the blocks in the cache
486 */
487 static errcode_t flush_cached_blocks(io_channel channel,
488 struct unix_private_data *data,
489 int invalidate)
490
491 {
492 struct unix_cache *cache;
493 errcode_t retval, retval2;
494 int i;
495
496 retval2 = 0;
497 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
498 if (!cache->in_use)
499 continue;
500
501 if (invalidate)
502 cache->in_use = 0;
503
504 if (!cache->dirty)
505 continue;
506
507 retval = raw_write_blk(channel, data,
508 cache->block, 1, cache->buf);
509 if (retval)
510 retval2 = retval;
511 else
512 cache->dirty = 0;
513 }
514 return retval2;
515 }
516 #endif /* NO_IO_CACHE */
517
518 #ifdef __linux__
519 #ifndef BLKDISCARDZEROES
520 #define BLKDISCARDZEROES _IO(0x12,124)
521 #endif
522 #endif
523
524 int ext2fs_open_file(const char *pathname, int flags, mode_t mode)
525 {
526 if (mode)
527 #if defined(HAVE_OPEN64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
528 return open64(pathname, flags, mode);
529 else
530 return open64(pathname, flags);
531 #else
532 return open(pathname, flags, mode);
533 else
534 return open(pathname, flags);
535 #endif
536 }
537
538 int ext2fs_stat(const char *path, ext2fs_struct_stat *buf)
539 {
540 #if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
541 return stat64(path, buf);
542 #else
543 return stat(path, buf);
544 #endif
545 }
546
547 int ext2fs_fstat(int fd, ext2fs_struct_stat *buf)
548 {
549 #if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
550 return fstat64(fd, buf);
551 #else
552 return fstat(fd, buf);
553 #endif
554 }
555
556
557 static errcode_t unix_open_channel(const char *name, int fd,
558 int flags, io_channel *channel,
559 io_manager io_mgr)
560 {
561 io_channel io = NULL;
562 struct unix_private_data *data = NULL;
563 errcode_t retval;
564 ext2fs_struct_stat st;
565 #ifdef __linux__
566 struct utsname ut;
567 #endif
568
569 if (safe_getenv("UNIX_IO_FORCE_BOUNCE"))
570 flags |= IO_FLAG_FORCE_BOUNCE;
571
572 #ifdef __linux__
573 /*
574 * We need to make sure any previous errors in the block
575 * device are thrown away, sigh.
576 */
577 (void) fsync(fd);
578 #endif
579
580 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
581 if (retval)
582 goto cleanup;
583 memset(io, 0, sizeof(struct struct_io_channel));
584 io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
585 retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data);
586 if (retval)
587 goto cleanup;
588
589 io->manager = io_mgr;
590 retval = ext2fs_get_mem(strlen(name)+1, &io->name);
591 if (retval)
592 goto cleanup;
593
594 strcpy(io->name, name);
595 io->private_data = data;
596 io->block_size = 1024;
597 io->read_error = 0;
598 io->write_error = 0;
599 io->refcount = 1;
600
601 memset(data, 0, sizeof(struct unix_private_data));
602 data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
603 data->io_stats.num_fields = 2;
604 data->flags = flags;
605 data->dev = fd;
606
607 #if defined(O_DIRECT)
608 if (flags & IO_FLAG_DIRECT_IO)
609 io->align = ext2fs_get_dio_alignment(data->dev);
610 #elif defined(F_NOCACHE)
611 if (flags & IO_FLAG_DIRECT_IO)
612 io->align = 4096;
613 #endif
614
615 /*
616 * If the device is really a block device, then set the
617 * appropriate flag, otherwise we can set DISCARD_ZEROES flag
618 * because we are going to use punch hole instead of discard
619 * and if it succeed, subsequent read from sparse area returns
620 * zero.
621 */
622 if (ext2fs_fstat(data->dev, &st) == 0) {
623 if (ext2fsP_is_disk_device(st.st_mode))
624 io->flags |= CHANNEL_FLAGS_BLOCK_DEVICE;
625 else
626 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
627 }
628
629 #ifdef BLKDISCARDZEROES
630 {
631 int zeroes = 0;
632 if (ioctl(data->dev, BLKDISCARDZEROES, &zeroes) == 0 &&
633 zeroes)
634 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
635 }
636 #endif
637
638 #if defined(__CYGWIN__)
639 /*
640 * Some operating systems require that the buffers be aligned,
641 * regardless of O_DIRECT
642 */
643 if (!io->align)
644 io->align = 512;
645 #endif
646
647 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
648 if (io->flags & CHANNEL_FLAGS_BLOCK_DEVICE) {
649 int dio_align = ext2fs_get_dio_alignment(fd);
650
651 if (io->align < dio_align)
652 io->align = dio_align;
653 }
654 #endif
655
656 if ((retval = alloc_cache(io, data)))
657 goto cleanup;
658
659 #ifdef BLKROGET
660 if (flags & IO_FLAG_RW) {
661 int error;
662 int readonly = 0;
663
664 /* Is the block device actually writable? */
665 error = ioctl(data->dev, BLKROGET, &readonly);
666 if (!error && readonly) {
667 retval = EPERM;
668 goto cleanup;
669 }
670 }
671 #endif
672
673 #ifdef __linux__
674 #undef RLIM_INFINITY
675 #if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4)))
676 #define RLIM_INFINITY ((unsigned long)(~0UL>>1))
677 #else
678 #define RLIM_INFINITY (~0UL)
679 #endif
680 /*
681 * Work around a bug in 2.4.10-2.4.18 kernels where writes to
682 * block devices are wrongly getting hit by the filesize
683 * limit. This workaround isn't perfect, since it won't work
684 * if glibc wasn't built against 2.2 header files. (Sigh.)
685 *
686 */
687 if ((flags & IO_FLAG_RW) &&
688 (uname(&ut) == 0) &&
689 ((ut.release[0] == '2') && (ut.release[1] == '.') &&
690 (ut.release[2] == '4') && (ut.release[3] == '.') &&
691 (ut.release[4] == '1') && (ut.release[5] >= '0') &&
692 (ut.release[5] < '8')) &&
693 (ext2fs_fstat(data->dev, &st) == 0) &&
694 (ext2fsP_is_disk_device(st.st_mode))) {
695 struct rlimit rlim;
696
697 rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;
698 setrlimit(RLIMIT_FSIZE, &rlim);
699 getrlimit(RLIMIT_FSIZE, &rlim);
700 if (((unsigned long) rlim.rlim_cur) <
701 ((unsigned long) rlim.rlim_max)) {
702 rlim.rlim_cur = rlim.rlim_max;
703 setrlimit(RLIMIT_FSIZE, &rlim);
704 }
705 }
706 #endif
707 *channel = io;
708 return 0;
709
710 cleanup:
711 if (data) {
712 if (data->dev >= 0)
713 close(data->dev);
714 free_cache(data);
715 ext2fs_free_mem(&data);
716 }
717 if (io) {
718 if (io->name) {
719 ext2fs_free_mem(&io->name);
720 }
721 ext2fs_free_mem(&io);
722 }
723 return retval;
724 }
725
726 static errcode_t unixfd_open(const char *str_fd, int flags,
727 io_channel *channel)
728 {
729 int fd;
730 int fd_flags;
731
732 fd = atoi(str_fd);
733 #if defined(HAVE_FCNTL)
734 fd_flags = fcntl(fd, F_GETFD);
735 if (fd_flags == -1)
736 return -EBADF;
737
738 flags = 0;
739 if (fd_flags & O_RDWR)
740 flags |= IO_FLAG_RW;
741 if (fd_flags & O_EXCL)
742 flags |= IO_FLAG_EXCLUSIVE;
743 #if defined(O_DIRECT)
744 if (fd_flags & O_DIRECT)
745 flags |= IO_FLAG_DIRECT_IO;
746 #endif
747 #endif /* HAVE_FCNTL */
748
749 return unix_open_channel(str_fd, fd, flags, channel, unixfd_io_manager);
750 }
751
752 static errcode_t unix_open(const char *name, int flags,
753 io_channel *channel)
754 {
755 int fd = -1;
756 int open_flags;
757
758 if (name == 0)
759 return EXT2_ET_BAD_DEVICE_NAME;
760
761 open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
762 if (flags & IO_FLAG_EXCLUSIVE)
763 open_flags |= O_EXCL;
764 #if defined(O_DIRECT)
765 if (flags & IO_FLAG_DIRECT_IO)
766 open_flags |= O_DIRECT;
767 #endif
768 fd = ext2fs_open_file(name, open_flags, 0);
769 if (fd < 0)
770 return errno;
771 #if defined(F_NOCACHE) && !defined(IO_DIRECT)
772 if (flags & IO_FLAG_DIRECT_IO) {
773 if (fcntl(fd, F_NOCACHE, 1) < 0)
774 return errno;
775 }
776 #endif
777 return unix_open_channel(name, fd, flags, channel, unix_io_manager);
778 }
779
780 static errcode_t unix_close(io_channel channel)
781 {
782 struct unix_private_data *data;
783 errcode_t retval = 0;
784
785 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
786 data = (struct unix_private_data *) channel->private_data;
787 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
788
789 if (--channel->refcount > 0)
790 return 0;
791
792 #ifndef NO_IO_CACHE
793 retval = flush_cached_blocks(channel, data, 0);
794 #endif
795
796 if (close(data->dev) < 0)
797 retval = errno;
798 free_cache(data);
799
800 ext2fs_free_mem(&channel->private_data);
801 if (channel->name)
802 ext2fs_free_mem(&channel->name);
803 ext2fs_free_mem(&channel);
804 return retval;
805 }
806
807 static errcode_t unix_set_blksize(io_channel channel, int blksize)
808 {
809 struct unix_private_data *data;
810 errcode_t retval;
811
812 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
813 data = (struct unix_private_data *) channel->private_data;
814 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
815
816 if (channel->block_size != blksize) {
817 #ifndef NO_IO_CACHE
818 if ((retval = flush_cached_blocks(channel, data, 0)))
819 return retval;
820 #endif
821
822 channel->block_size = blksize;
823 free_cache(data);
824 if ((retval = alloc_cache(channel, data)))
825 return retval;
826 }
827 return 0;
828 }
829
830 static errcode_t unix_read_blk64(io_channel channel, unsigned long long block,
831 int count, void *buf)
832 {
833 struct unix_private_data *data;
834 struct unix_cache *cache, *reuse[READ_DIRECT_SIZE];
835 errcode_t retval;
836 char *cp;
837 int i, j;
838
839 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
840 data = (struct unix_private_data *) channel->private_data;
841 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
842
843 #ifdef NO_IO_CACHE
844 return raw_read_blk(channel, data, block, count, buf);
845 #else
846 /*
847 * If we're doing an odd-sized read or a very large read,
848 * flush out the cache and then do a direct read.
849 */
850 if (count < 0 || count > WRITE_DIRECT_SIZE) {
851 if ((retval = flush_cached_blocks(channel, data, 0)))
852 return retval;
853 return raw_read_blk(channel, data, block, count, buf);
854 }
855
856 cp = buf;
857 while (count > 0) {
858 /* If it's in the cache, use it! */
859 if ((cache = find_cached_block(data, block, &reuse[0]))) {
860 #ifdef DEBUG
861 printf("Using cached block %lu\n", block);
862 #endif
863 memcpy(cp, cache->buf, channel->block_size);
864 count--;
865 block++;
866 cp += channel->block_size;
867 continue;
868 }
869 if (count == 1) {
870 /*
871 * Special case where we read directly into the
872 * cache buffer; important in the O_DIRECT case
873 */
874 cache = reuse[0];
875 reuse_cache(channel, data, cache, block);
876 if ((retval = raw_read_blk(channel, data, block, 1,
877 cache->buf))) {
878 cache->in_use = 0;
879 return retval;
880 }
881 memcpy(cp, cache->buf, channel->block_size);
882 return 0;
883 }
884
885 /*
886 * Find the number of uncached blocks so we can do a
887 * single read request
888 */
889 for (i=1; i < count; i++)
890 if (find_cached_block(data, block+i, &reuse[i]))
891 break;
892 #ifdef DEBUG
893 printf("Reading %d blocks starting at %lu\n", i, block);
894 #endif
895 if ((retval = raw_read_blk(channel, data, block, i, cp)))
896 return retval;
897
898 /* Save the results in the cache */
899 for (j=0; j < i; j++) {
900 count--;
901 cache = reuse[j];
902 reuse_cache(channel, data, cache, block++);
903 memcpy(cache->buf, cp, channel->block_size);
904 cp += channel->block_size;
905 }
906 }
907 return 0;
908 #endif /* NO_IO_CACHE */
909 }
910
911 static errcode_t unix_read_blk(io_channel channel, unsigned long block,
912 int count, void *buf)
913 {
914 return unix_read_blk64(channel, block, count, buf);
915 }
916
917 static errcode_t unix_write_blk64(io_channel channel, unsigned long long block,
918 int count, const void *buf)
919 {
920 struct unix_private_data *data;
921 struct unix_cache *cache, *reuse;
922 errcode_t retval = 0;
923 const char *cp;
924 int writethrough;
925
926 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
927 data = (struct unix_private_data *) channel->private_data;
928 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
929
930 #ifdef NO_IO_CACHE
931 return raw_write_blk(channel, data, block, count, buf);
932 #else
933 /*
934 * If we're doing an odd-sized write or a very large write,
935 * flush out the cache completely and then do a direct write.
936 */
937 if (count < 0 || count > WRITE_DIRECT_SIZE) {
938 if ((retval = flush_cached_blocks(channel, data, 1)))
939 return retval;
940 return raw_write_blk(channel, data, block, count, buf);
941 }
942
943 /*
944 * For a moderate-sized multi-block write, first force a write
945 * if we're in write-through cache mode, and then fill the
946 * cache with the blocks.
947 */
948 writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH;
949 if (writethrough)
950 retval = raw_write_blk(channel, data, block, count, buf);
951
952 cp = buf;
953 while (count > 0) {
954 cache = find_cached_block(data, block, &reuse);
955 if (!cache) {
956 cache = reuse;
957 reuse_cache(channel, data, cache, block);
958 }
959 if (cache->buf != cp)
960 memcpy(cache->buf, cp, channel->block_size);
961 cache->dirty = !writethrough;
962 count--;
963 block++;
964 cp += channel->block_size;
965 }
966 return retval;
967 #endif /* NO_IO_CACHE */
968 }
969
970 static errcode_t unix_cache_readahead(io_channel channel,
971 unsigned long long block,
972 unsigned long long count)
973 {
974 #ifdef POSIX_FADV_WILLNEED
975 struct unix_private_data *data;
976
977 data = (struct unix_private_data *)channel->private_data;
978 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
979 return posix_fadvise(data->dev,
980 (ext2_loff_t)block * channel->block_size + data->offset,
981 (ext2_loff_t)count * channel->block_size,
982 POSIX_FADV_WILLNEED);
983 #else
984 return EXT2_ET_OP_NOT_SUPPORTED;
985 #endif
986 }
987
988 static errcode_t unix_write_blk(io_channel channel, unsigned long block,
989 int count, const void *buf)
990 {
991 return unix_write_blk64(channel, block, count, buf);
992 }
993
994 static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
995 int size, const void *buf)
996 {
997 struct unix_private_data *data;
998 errcode_t retval = 0;
999 ssize_t actual;
1000
1001 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
1002 data = (struct unix_private_data *) channel->private_data;
1003 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
1004
1005 if (channel->align != 0) {
1006 #ifdef ALIGN_DEBUG
1007 printf("unix_write_byte: O_DIRECT fallback\n");
1008 #endif
1009 return EXT2_ET_UNIMPLEMENTED;
1010 }
1011
1012 #ifndef NO_IO_CACHE
1013 /*
1014 * Flush out the cache completely
1015 */
1016 if ((retval = flush_cached_blocks(channel, data, 1)))
1017 return retval;
1018 #endif
1019
1020 if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0)
1021 return errno;
1022
1023 actual = write(data->dev, buf, size);
1024 if (actual < 0)
1025 return errno;
1026 if (actual != size)
1027 return EXT2_ET_SHORT_WRITE;
1028
1029 return 0;
1030 }
1031
1032 /*
1033 * Flush data buffers to disk.
1034 */
1035 static errcode_t unix_flush(io_channel channel)
1036 {
1037 struct unix_private_data *data;
1038 errcode_t retval = 0;
1039
1040 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
1041 data = (struct unix_private_data *) channel->private_data;
1042 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
1043
1044 #ifndef NO_IO_CACHE
1045 retval = flush_cached_blocks(channel, data, 0);
1046 #endif
1047 #ifdef HAVE_FSYNC
1048 if (!retval && fsync(data->dev) != 0)
1049 return errno;
1050 #endif
1051 return retval;
1052 }
1053
1054 static errcode_t unix_set_option(io_channel channel, const char *option,
1055 const char *arg)
1056 {
1057 struct unix_private_data *data;
1058 unsigned long long tmp;
1059 char *end;
1060
1061 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
1062 data = (struct unix_private_data *) channel->private_data;
1063 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
1064
1065 if (!strcmp(option, "offset")) {
1066 if (!arg)
1067 return EXT2_ET_INVALID_ARGUMENT;
1068
1069 tmp = strtoull(arg, &end, 0);
1070 if (*end)
1071 return EXT2_ET_INVALID_ARGUMENT;
1072 data->offset = tmp;
1073 if (data->offset < 0)
1074 return EXT2_ET_INVALID_ARGUMENT;
1075 return 0;
1076 }
1077 return EXT2_ET_INVALID_ARGUMENT;
1078 }
1079
1080 #if defined(__linux__) && !defined(BLKDISCARD)
1081 #define BLKDISCARD _IO(0x12,119)
1082 #endif
1083
1084 static errcode_t unix_discard(io_channel channel, unsigned long long block,
1085 unsigned long long count)
1086 {
1087 struct unix_private_data *data;
1088 int ret;
1089
1090 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
1091 data = (struct unix_private_data *) channel->private_data;
1092 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
1093
1094 if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) {
1095 #ifdef BLKDISCARD
1096 __u64 range[2];
1097
1098 range[0] = (__u64)(block) * channel->block_size + data->offset;
1099 range[1] = (__u64)(count) * channel->block_size;
1100
1101 ret = ioctl(data->dev, BLKDISCARD, &range);
1102 #else
1103 goto unimplemented;
1104 #endif
1105 } else {
1106 #if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE)
1107 /*
1108 * If we are not on block device, try to use punch hole
1109 * to reclaim free space.
1110 */
1111 ret = fallocate(data->dev,
1112 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
1113 (off_t)(block) * channel->block_size + data->offset,
1114 (off_t)(count) * channel->block_size);
1115 #else
1116 goto unimplemented;
1117 #endif
1118 }
1119 if (ret < 0) {
1120 if (errno == EOPNOTSUPP)
1121 goto unimplemented;
1122 return errno;
1123 }
1124 return 0;
1125 unimplemented:
1126 return EXT2_ET_UNIMPLEMENTED;
1127 }
1128
1129 /*
1130 * If we know about ZERO_RANGE, try that before we try PUNCH_HOLE because
1131 * ZERO_RANGE doesn't unmap preallocated blocks. We prefer fallocate because
1132 * it always invalidates page cache, and libext2fs requires that reads after
1133 * ZERO_RANGE return zeroes.
1134 */
1135 static int __unix_zeroout(int fd, off_t offset, off_t len)
1136 {
1137 int ret = -1;
1138
1139 #if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_ZERO_RANGE)
1140 ret = fallocate(fd, FALLOC_FL_ZERO_RANGE, offset, len);
1141 if (ret == 0)
1142 return 0;
1143 #endif
1144 #if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE) && defined(FALLOC_FL_KEEP_SIZE)
1145 ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
1146 offset, len);
1147 if (ret == 0)
1148 return 0;
1149 #endif
1150 errno = EOPNOTSUPP;
1151 return ret;
1152 }
1153
1154 /* parameters might not be used if OS doesn't support zeroout */
1155 #if __GNUC_PREREQ (4, 6)
1156 #pragma GCC diagnostic push
1157 #pragma GCC diagnostic ignored "-Wunused-parameter"
1158 #endif
1159 static errcode_t unix_zeroout(io_channel channel, unsigned long long block,
1160 unsigned long long count)
1161 {
1162 struct unix_private_data *data;
1163 int ret;
1164
1165 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
1166 data = (struct unix_private_data *) channel->private_data;
1167 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
1168
1169 if (safe_getenv("UNIX_IO_NOZEROOUT"))
1170 goto unimplemented;
1171
1172 if (!(channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE)) {
1173 /* Regular file, try to use truncate/punch/zero. */
1174 struct stat statbuf;
1175
1176 if (count == 0)
1177 return 0;
1178 /*
1179 * If we're trying to zero a range past the end of the file,
1180 * extend the file size, then truncate everything.
1181 */
1182 ret = fstat(data->dev, &statbuf);
1183 if (ret)
1184 goto err;
1185 if ((unsigned long long) statbuf.st_size <
1186 (block + count) * channel->block_size + data->offset) {
1187 ret = ftruncate(data->dev,
1188 (block + count) * channel->block_size + data->offset);
1189 if (ret)
1190 goto err;
1191 }
1192 }
1193
1194 ret = __unix_zeroout(data->dev,
1195 (off_t)(block) * channel->block_size + data->offset,
1196 (off_t)(count) * channel->block_size);
1197 err:
1198 if (ret < 0) {
1199 if (errno == EOPNOTSUPP)
1200 goto unimplemented;
1201 return errno;
1202 }
1203 return 0;
1204 unimplemented:
1205 return EXT2_ET_UNIMPLEMENTED;
1206 }
1207 #if __GNUC_PREREQ (4, 6)
1208 #pragma GCC diagnostic pop
1209 #endif
1210
1211 static struct struct_io_manager struct_unix_manager = {
1212 .magic = EXT2_ET_MAGIC_IO_MANAGER,
1213 .name = "Unix I/O Manager",
1214 .open = unix_open,
1215 .close = unix_close,
1216 .set_blksize = unix_set_blksize,
1217 .read_blk = unix_read_blk,
1218 .write_blk = unix_write_blk,
1219 .flush = unix_flush,
1220 .write_byte = unix_write_byte,
1221 .set_option = unix_set_option,
1222 .get_stats = unix_get_stats,
1223 .read_blk64 = unix_read_blk64,
1224 .write_blk64 = unix_write_blk64,
1225 .discard = unix_discard,
1226 .cache_readahead = unix_cache_readahead,
1227 .zeroout = unix_zeroout,
1228 };
1229
1230 io_manager unix_io_manager = &struct_unix_manager;
1231
1232 static struct struct_io_manager struct_unixfd_manager = {
1233 .magic = EXT2_ET_MAGIC_IO_MANAGER,
1234 .name = "Unix fd I/O Manager",
1235 .open = unixfd_open,
1236 .close = unix_close,
1237 .set_blksize = unix_set_blksize,
1238 .read_blk = unix_read_blk,
1239 .write_blk = unix_write_blk,
1240 .flush = unix_flush,
1241 .write_byte = unix_write_byte,
1242 .set_option = unix_set_option,
1243 .get_stats = unix_get_stats,
1244 .read_blk64 = unix_read_blk64,
1245 .write_blk64 = unix_write_blk64,
1246 .discard = unix_discard,
1247 .cache_readahead = unix_cache_readahead,
1248 .zeroout = unix_zeroout,
1249 };
1250
1251 io_manager unixfd_io_manager = &struct_unixfd_manager;
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