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