unix_io.c revision 1d6fd6d0c3766a8165e69284c75812574a29c804
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 "config.h" 25#include <stdio.h> 26#include <string.h> 27#if HAVE_UNISTD_H 28#include <unistd.h> 29#endif 30#if HAVE_ERRNO_H 31#include <errno.h> 32#endif 33#include <fcntl.h> 34#include <time.h> 35#ifdef __linux__ 36#include <sys/utsname.h> 37#endif 38#ifdef HAVE_SYS_IOCTL_H 39#include <sys/ioctl.h> 40#endif 41#ifdef HAVE_SYS_MOUNT_H 42#include <sys/mount.h> 43#endif 44#if HAVE_SYS_STAT_H 45#include <sys/stat.h> 46#endif 47#if HAVE_SYS_TYPES_H 48#include <sys/types.h> 49#endif 50#if HAVE_SYS_RESOURCE_H 51#include <sys/resource.h> 52#endif 53#if HAVE_LINUX_FALLOC_H 54#include <linux/falloc.h> 55#endif 56 57#if defined(__linux__) && defined(_IO) && !defined(BLKROGET) 58#define BLKROGET _IO(0x12, 94) /* Get read-only status (0 = read_write). */ 59#endif 60 61#undef ALIGN_DEBUG 62 63#include "ext2_fs.h" 64#include "ext2fs.h" 65 66/* 67 * For checking structure magic numbers... 68 */ 69 70#define EXT2_CHECK_MAGIC(struct, code) \ 71 if ((struct)->magic != (code)) return (code) 72 73struct unix_cache { 74 char *buf; 75 unsigned long long block; 76 int access_time; 77 unsigned dirty:1; 78 unsigned in_use:1; 79}; 80 81#define CACHE_SIZE 8 82#define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */ 83#define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */ 84 85struct unix_private_data { 86 int magic; 87 int dev; 88 int flags; 89 int align; 90 int access_time; 91 ext2_loff_t offset; 92 struct unix_cache cache[CACHE_SIZE]; 93 void *bounce; 94 struct struct_io_stats io_stats; 95}; 96 97#define IS_ALIGNED(n, align) ((((unsigned long) n) & \ 98 ((unsigned long) ((align)-1))) == 0) 99 100static errcode_t unix_open(const char *name, int flags, io_channel *channel); 101static errcode_t unix_close(io_channel channel); 102static errcode_t unix_set_blksize(io_channel channel, int blksize); 103static errcode_t unix_read_blk(io_channel channel, unsigned long block, 104 int count, void *data); 105static errcode_t unix_write_blk(io_channel channel, unsigned long block, 106 int count, const void *data); 107static errcode_t unix_flush(io_channel channel); 108static errcode_t unix_write_byte(io_channel channel, unsigned long offset, 109 int size, const void *data); 110static errcode_t unix_set_option(io_channel channel, const char *option, 111 const char *arg); 112static errcode_t unix_get_stats(io_channel channel, io_stats *stats) 113; 114static void reuse_cache(io_channel channel, struct unix_private_data *data, 115 struct unix_cache *cache, unsigned long long block); 116static errcode_t unix_read_blk64(io_channel channel, unsigned long long block, 117 int count, void *data); 118static errcode_t unix_write_blk64(io_channel channel, unsigned long long block, 119 int count, const void *data); 120static errcode_t unix_discard(io_channel channel, unsigned long long block, 121 unsigned long long count); 122 123static struct struct_io_manager struct_unix_manager = { 124 EXT2_ET_MAGIC_IO_MANAGER, 125 "Unix I/O Manager", 126 unix_open, 127 unix_close, 128 unix_set_blksize, 129 unix_read_blk, 130 unix_write_blk, 131 unix_flush, 132 unix_write_byte, 133 unix_set_option, 134 unix_get_stats, 135 unix_read_blk64, 136 unix_write_blk64, 137 unix_discard, 138}; 139 140io_manager unix_io_manager = &struct_unix_manager; 141 142static errcode_t unix_get_stats(io_channel channel, io_stats *stats) 143{ 144 errcode_t retval = 0; 145 146 struct unix_private_data *data; 147 148 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 149 data = (struct unix_private_data *) channel->private_data; 150 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 151 152 if (stats) 153 *stats = &data->io_stats; 154 155 return retval; 156} 157 158/* 159 * Here are the raw I/O functions 160 */ 161static errcode_t raw_read_blk(io_channel channel, 162 struct unix_private_data *data, 163 unsigned long long block, 164 int count, void *bufv) 165{ 166 errcode_t retval; 167 ssize_t size; 168 ext2_loff_t location; 169 int actual = 0; 170 unsigned char *buf = bufv; 171 172 size = (count < 0) ? -count : count * channel->block_size; 173 data->io_stats.bytes_read += size; 174 location = ((ext2_loff_t) block * channel->block_size) + data->offset; 175 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) { 176 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED; 177 goto error_out; 178 } 179 if ((channel->align == 0) || 180 (IS_ALIGNED(buf, channel->align) && 181 IS_ALIGNED(size, channel->align))) { 182 actual = read(data->dev, buf, size); 183 if (actual != size) { 184 short_read: 185 if (actual < 0) 186 actual = 0; 187 retval = EXT2_ET_SHORT_READ; 188 goto error_out; 189 } 190 return 0; 191 } 192 193#ifdef ALIGN_DEBUG 194 printf("raw_read_blk: O_DIRECT fallback: %p %lu\n", buf, 195 (unsigned long) size); 196#endif 197 198 /* 199 * The buffer or size which we're trying to read isn't aligned 200 * to the O_DIRECT rules, so we need to do this the hard way... 201 */ 202 while (size > 0) { 203 actual = read(data->dev, data->bounce, channel->block_size); 204 if (actual != channel->block_size) 205 goto short_read; 206 actual = size; 207 if (size > channel->block_size) 208 actual = channel->block_size; 209 memcpy(buf, data->bounce, actual); 210 size -= actual; 211 buf += actual; 212 } 213 return 0; 214 215error_out: 216 memset((char *) buf+actual, 0, size-actual); 217 if (channel->read_error) 218 retval = (channel->read_error)(channel, block, count, buf, 219 size, actual, retval); 220 return retval; 221} 222 223static errcode_t raw_write_blk(io_channel channel, 224 struct unix_private_data *data, 225 unsigned long long block, 226 int count, const void *bufv) 227{ 228 ssize_t size; 229 ext2_loff_t location; 230 int actual = 0; 231 errcode_t retval; 232 const unsigned char *buf = bufv; 233 234 if (count == 1) 235 size = channel->block_size; 236 else { 237 if (count < 0) 238 size = -count; 239 else 240 size = count * channel->block_size; 241 } 242 data->io_stats.bytes_written += size; 243 244 location = ((ext2_loff_t) block * channel->block_size) + data->offset; 245 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) { 246 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED; 247 goto error_out; 248 } 249 250 if ((channel->align == 0) || 251 (IS_ALIGNED(buf, channel->align) && 252 IS_ALIGNED(size, channel->align))) { 253 actual = write(data->dev, buf, size); 254 if (actual != size) { 255 short_write: 256 retval = EXT2_ET_SHORT_WRITE; 257 goto error_out; 258 } 259 return 0; 260 } 261 262#ifdef ALIGN_DEBUG 263 printf("raw_write_blk: O_DIRECT fallback: %p %lu\n", buf, 264 (unsigned long) size); 265#endif 266 /* 267 * The buffer or size which we're trying to write isn't aligned 268 * to the O_DIRECT rules, so we need to do this the hard way... 269 */ 270 while (size > 0) { 271 if (size < channel->block_size) { 272 actual = read(data->dev, data->bounce, 273 channel->block_size); 274 if (actual != channel->block_size) { 275 retval = EXT2_ET_SHORT_READ; 276 goto error_out; 277 } 278 } 279 actual = size; 280 if (size > channel->block_size) 281 actual = channel->block_size; 282 memcpy(data->bounce, buf, actual); 283 actual = write(data->dev, data->bounce, channel->block_size); 284 if (actual != channel->block_size) 285 goto short_write; 286 size -= actual; 287 buf += actual; 288 } 289 return 0; 290 291error_out: 292 if (channel->write_error) 293 retval = (channel->write_error)(channel, block, count, buf, 294 size, actual, retval); 295 return retval; 296} 297 298 299/* 300 * Here we implement the cache functions 301 */ 302 303/* Allocate the cache buffers */ 304static errcode_t alloc_cache(io_channel channel, 305 struct unix_private_data *data) 306{ 307 errcode_t retval; 308 struct unix_cache *cache; 309 int i; 310 311 data->access_time = 0; 312 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 313 cache->block = 0; 314 cache->access_time = 0; 315 cache->dirty = 0; 316 cache->in_use = 0; 317 if (cache->buf) 318 ext2fs_free_mem(&cache->buf); 319 retval = io_channel_alloc_buf(channel, 0, &cache->buf); 320 if (retval) 321 return retval; 322 } 323 if (channel->align) { 324 if (data->bounce) 325 ext2fs_free_mem(&data->bounce); 326 retval = io_channel_alloc_buf(channel, 0, &data->bounce); 327 } 328 return retval; 329} 330 331/* Free the cache buffers */ 332static void free_cache(struct unix_private_data *data) 333{ 334 struct unix_cache *cache; 335 int i; 336 337 data->access_time = 0; 338 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 339 cache->block = 0; 340 cache->access_time = 0; 341 cache->dirty = 0; 342 cache->in_use = 0; 343 if (cache->buf) 344 ext2fs_free_mem(&cache->buf); 345 } 346 if (data->bounce) 347 ext2fs_free_mem(&data->bounce); 348} 349 350#ifndef NO_IO_CACHE 351/* 352 * Try to find a block in the cache. If the block is not found, and 353 * eldest is a non-zero pointer, then fill in eldest with the cache 354 * entry to that should be reused. 355 */ 356static struct unix_cache *find_cached_block(struct unix_private_data *data, 357 unsigned long long block, 358 struct unix_cache **eldest) 359{ 360 struct unix_cache *cache, *unused_cache, *oldest_cache; 361 int i; 362 363 unused_cache = oldest_cache = 0; 364 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 365 if (!cache->in_use) { 366 if (!unused_cache) 367 unused_cache = cache; 368 continue; 369 } 370 if (cache->block == block) { 371 cache->access_time = ++data->access_time; 372 return cache; 373 } 374 if (!oldest_cache || 375 (cache->access_time < oldest_cache->access_time)) 376 oldest_cache = cache; 377 } 378 if (eldest) 379 *eldest = (unused_cache) ? unused_cache : oldest_cache; 380 return 0; 381} 382 383/* 384 * Reuse a particular cache entry for another block. 385 */ 386static void reuse_cache(io_channel channel, struct unix_private_data *data, 387 struct unix_cache *cache, unsigned long long block) 388{ 389 if (cache->dirty && cache->in_use) 390 raw_write_blk(channel, data, cache->block, 1, cache->buf); 391 392 cache->in_use = 1; 393 cache->dirty = 0; 394 cache->block = block; 395 cache->access_time = ++data->access_time; 396} 397 398/* 399 * Flush all of the blocks in the cache 400 */ 401static errcode_t flush_cached_blocks(io_channel channel, 402 struct unix_private_data *data, 403 int invalidate) 404 405{ 406 struct unix_cache *cache; 407 errcode_t retval, retval2; 408 int i; 409 410 retval2 = 0; 411 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 412 if (!cache->in_use) 413 continue; 414 415 if (invalidate) 416 cache->in_use = 0; 417 418 if (!cache->dirty) 419 continue; 420 421 retval = raw_write_blk(channel, data, 422 cache->block, 1, cache->buf); 423 if (retval) 424 retval2 = retval; 425 else 426 cache->dirty = 0; 427 } 428 return retval2; 429} 430#endif /* NO_IO_CACHE */ 431 432#ifdef __linux__ 433#ifndef BLKDISCARDZEROES 434#define BLKDISCARDZEROES _IO(0x12,124) 435#endif 436#endif 437 438int ext2fs_open_file(const char *pathname, int flags, mode_t mode) 439{ 440 if (mode) 441#if defined(HAVE_OPEN64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED) 442 return open64(pathname, flags, mode); 443 else 444 return open64(pathname, flags); 445#else 446 return open(pathname, flags, mode); 447 else 448 return open(pathname, flags); 449#endif 450} 451 452int ext2fs_stat(const char *path, ext2fs_struct_stat *buf) 453{ 454#if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED) 455 return stat64(path, buf); 456#else 457 return stat(path, buf); 458#endif 459} 460 461int ext2fs_fstat(int fd, ext2fs_struct_stat *buf) 462{ 463#if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED) 464 return fstat64(fd, buf); 465#else 466 return fstat(fd, buf); 467#endif 468} 469 470static errcode_t unix_open(const char *name, int flags, io_channel *channel) 471{ 472 io_channel io = NULL; 473 struct unix_private_data *data = NULL; 474 errcode_t retval; 475 int open_flags; 476 int f_nocache = 0; 477 ext2fs_struct_stat st; 478#ifdef __linux__ 479 struct utsname ut; 480#endif 481 482 if (name == 0) 483 return EXT2_ET_BAD_DEVICE_NAME; 484 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io); 485 if (retval) 486 goto cleanup; 487 memset(io, 0, sizeof(struct struct_io_channel)); 488 io->magic = EXT2_ET_MAGIC_IO_CHANNEL; 489 retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data); 490 if (retval) 491 goto cleanup; 492 493 io->manager = unix_io_manager; 494 retval = ext2fs_get_mem(strlen(name)+1, &io->name); 495 if (retval) 496 goto cleanup; 497 498 strcpy(io->name, name); 499 io->private_data = data; 500 io->block_size = 1024; 501 io->read_error = 0; 502 io->write_error = 0; 503 io->refcount = 1; 504 505 memset(data, 0, sizeof(struct unix_private_data)); 506 data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL; 507 data->io_stats.num_fields = 2; 508 data->dev = -1; 509 510 open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY; 511 if (flags & IO_FLAG_EXCLUSIVE) 512 open_flags |= O_EXCL; 513#if defined(O_DIRECT) 514 if (flags & IO_FLAG_DIRECT_IO) { 515 open_flags |= O_DIRECT; 516 io->align = ext2fs_get_dio_alignment(data->dev); 517 } 518#elif defined(F_NOCACHE) 519 if (flags & IO_FLAG_DIRECT_IO) { 520 f_nocache = F_NOCACHE; 521 io->align = 4096; 522 } 523#endif 524 data->flags = flags; 525 526 data->dev = ext2fs_open_file(io->name, open_flags, 0); 527 if (data->dev < 0) { 528 retval = errno; 529 goto cleanup; 530 } 531 if (f_nocache) { 532 if (fcntl(data->dev, f_nocache, 1) < 0) { 533 retval = errno; 534 goto cleanup; 535 } 536 } 537 538 /* 539 * If the device is really a block device, then set the 540 * appropriate flag, otherwise we can set DISCARD_ZEROES flag 541 * because we are going to use punch hole instead of discard 542 * and if it succeed, subsequent read from sparse area returns 543 * zero. 544 */ 545 if (ext2fs_stat(io->name, &st) == 0) { 546 if (S_ISBLK(st.st_mode)) 547 io->flags |= CHANNEL_FLAGS_BLOCK_DEVICE; 548 else 549 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES; 550 } 551 552#ifdef BLKDISCARDZEROES 553 { 554 int zeroes = 0; 555 if (ioctl(data->dev, BLKDISCARDZEROES, &zeroes) == 0 && 556 zeroes) 557 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES; 558 } 559#endif 560 561#if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) 562 /* 563 * Some operating systems require that the buffers be aligned, 564 * regardless of O_DIRECT 565 */ 566 if (!io->align) 567 io->align = 512; 568#endif 569 570 571 if ((retval = alloc_cache(io, data))) 572 goto cleanup; 573 574#ifdef BLKROGET 575 if (flags & IO_FLAG_RW) { 576 int error; 577 int readonly = 0; 578 579 /* Is the block device actually writable? */ 580 error = ioctl(data->dev, BLKROGET, &readonly); 581 if (!error && readonly) { 582 retval = EPERM; 583 goto cleanup; 584 } 585 } 586#endif 587 588#ifdef __linux__ 589#undef RLIM_INFINITY 590#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4))) 591#define RLIM_INFINITY ((unsigned long)(~0UL>>1)) 592#else 593#define RLIM_INFINITY (~0UL) 594#endif 595 /* 596 * Work around a bug in 2.4.10-2.4.18 kernels where writes to 597 * block devices are wrongly getting hit by the filesize 598 * limit. This workaround isn't perfect, since it won't work 599 * if glibc wasn't built against 2.2 header files. (Sigh.) 600 * 601 */ 602 if ((flags & IO_FLAG_RW) && 603 (uname(&ut) == 0) && 604 ((ut.release[0] == '2') && (ut.release[1] == '.') && 605 (ut.release[2] == '4') && (ut.release[3] == '.') && 606 (ut.release[4] == '1') && (ut.release[5] >= '0') && 607 (ut.release[5] < '8')) && 608 (ext2fs_stat(io->name, &st) == 0) && 609 (S_ISBLK(st.st_mode))) { 610 struct rlimit rlim; 611 612 rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY; 613 setrlimit(RLIMIT_FSIZE, &rlim); 614 getrlimit(RLIMIT_FSIZE, &rlim); 615 if (((unsigned long) rlim.rlim_cur) < 616 ((unsigned long) rlim.rlim_max)) { 617 rlim.rlim_cur = rlim.rlim_max; 618 setrlimit(RLIMIT_FSIZE, &rlim); 619 } 620 } 621#endif 622 *channel = io; 623 return 0; 624 625cleanup: 626 if (data) { 627 if (data->dev >= 0) 628 close(data->dev); 629 free_cache(data); 630 ext2fs_free_mem(&data); 631 } 632 if (io) { 633 if (io->name) { 634 ext2fs_free_mem(&io->name); 635 } 636 ext2fs_free_mem(&io); 637 } 638 return retval; 639} 640 641static errcode_t unix_close(io_channel channel) 642{ 643 struct unix_private_data *data; 644 errcode_t retval = 0; 645 646 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 647 data = (struct unix_private_data *) channel->private_data; 648 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 649 650 if (--channel->refcount > 0) 651 return 0; 652 653#ifndef NO_IO_CACHE 654 retval = flush_cached_blocks(channel, data, 0); 655#endif 656 657 if (close(data->dev) < 0) 658 retval = errno; 659 free_cache(data); 660 661 ext2fs_free_mem(&channel->private_data); 662 if (channel->name) 663 ext2fs_free_mem(&channel->name); 664 ext2fs_free_mem(&channel); 665 return retval; 666} 667 668static errcode_t unix_set_blksize(io_channel channel, int blksize) 669{ 670 struct unix_private_data *data; 671 errcode_t retval; 672 673 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 674 data = (struct unix_private_data *) channel->private_data; 675 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 676 677 if (channel->block_size != blksize) { 678#ifndef NO_IO_CACHE 679 if ((retval = flush_cached_blocks(channel, data, 0))) 680 return retval; 681#endif 682 683 channel->block_size = blksize; 684 free_cache(data); 685 if ((retval = alloc_cache(channel, data))) 686 return retval; 687 } 688 return 0; 689} 690 691 692static errcode_t unix_read_blk64(io_channel channel, unsigned long long block, 693 int count, void *buf) 694{ 695 struct unix_private_data *data; 696 struct unix_cache *cache, *reuse[READ_DIRECT_SIZE]; 697 errcode_t retval; 698 char *cp; 699 int i, j; 700 701 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 702 data = (struct unix_private_data *) channel->private_data; 703 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 704 705#ifdef NO_IO_CACHE 706 return raw_read_blk(channel, data, block, count, buf); 707#else 708 /* 709 * If we're doing an odd-sized read or a very large read, 710 * flush out the cache and then do a direct read. 711 */ 712 if (count < 0 || count > WRITE_DIRECT_SIZE) { 713 if ((retval = flush_cached_blocks(channel, data, 0))) 714 return retval; 715 return raw_read_blk(channel, data, block, count, buf); 716 } 717 718 cp = buf; 719 while (count > 0) { 720 /* If it's in the cache, use it! */ 721 if ((cache = find_cached_block(data, block, &reuse[0]))) { 722#ifdef DEBUG 723 printf("Using cached block %lu\n", block); 724#endif 725 memcpy(cp, cache->buf, channel->block_size); 726 count--; 727 block++; 728 cp += channel->block_size; 729 continue; 730 } 731 if (count == 1) { 732 /* 733 * Special case where we read directly into the 734 * cache buffer; important in the O_DIRECT case 735 */ 736 cache = reuse[0]; 737 reuse_cache(channel, data, cache, block); 738 if ((retval = raw_read_blk(channel, data, block, 1, 739 cache->buf))) { 740 cache->in_use = 0; 741 return retval; 742 } 743 memcpy(cp, cache->buf, channel->block_size); 744 return 0; 745 } 746 747 /* 748 * Find the number of uncached blocks so we can do a 749 * single read request 750 */ 751 for (i=1; i < count; i++) 752 if (find_cached_block(data, block+i, &reuse[i])) 753 break; 754#ifdef DEBUG 755 printf("Reading %d blocks starting at %lu\n", i, block); 756#endif 757 if ((retval = raw_read_blk(channel, data, block, i, cp))) 758 return retval; 759 760 /* Save the results in the cache */ 761 for (j=0; j < i; j++) { 762 count--; 763 cache = reuse[j]; 764 reuse_cache(channel, data, cache, block++); 765 memcpy(cache->buf, cp, channel->block_size); 766 cp += channel->block_size; 767 } 768 } 769 return 0; 770#endif /* NO_IO_CACHE */ 771} 772 773static errcode_t unix_read_blk(io_channel channel, unsigned long block, 774 int count, void *buf) 775{ 776 return unix_read_blk64(channel, block, count, buf); 777} 778 779static errcode_t unix_write_blk64(io_channel channel, unsigned long long block, 780 int count, const void *buf) 781{ 782 struct unix_private_data *data; 783 struct unix_cache *cache, *reuse; 784 errcode_t retval = 0; 785 const char *cp; 786 int writethrough; 787 788 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 789 data = (struct unix_private_data *) channel->private_data; 790 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 791 792#ifdef NO_IO_CACHE 793 return raw_write_blk(channel, data, block, count, buf); 794#else 795 /* 796 * If we're doing an odd-sized write or a very large write, 797 * flush out the cache completely and then do a direct write. 798 */ 799 if (count < 0 || count > WRITE_DIRECT_SIZE) { 800 if ((retval = flush_cached_blocks(channel, data, 1))) 801 return retval; 802 return raw_write_blk(channel, data, block, count, buf); 803 } 804 805 /* 806 * For a moderate-sized multi-block write, first force a write 807 * if we're in write-through cache mode, and then fill the 808 * cache with the blocks. 809 */ 810 writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH; 811 if (writethrough) 812 retval = raw_write_blk(channel, data, block, count, buf); 813 814 cp = buf; 815 while (count > 0) { 816 cache = find_cached_block(data, block, &reuse); 817 if (!cache) { 818 cache = reuse; 819 reuse_cache(channel, data, cache, block); 820 } 821 memcpy(cache->buf, cp, channel->block_size); 822 cache->dirty = !writethrough; 823 count--; 824 block++; 825 cp += channel->block_size; 826 } 827 return retval; 828#endif /* NO_IO_CACHE */ 829} 830 831static errcode_t unix_write_blk(io_channel channel, unsigned long block, 832 int count, const void *buf) 833{ 834 return unix_write_blk64(channel, block, count, buf); 835} 836 837static errcode_t unix_write_byte(io_channel channel, unsigned long offset, 838 int size, const void *buf) 839{ 840 struct unix_private_data *data; 841 errcode_t retval = 0; 842 ssize_t actual; 843 844 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 845 data = (struct unix_private_data *) channel->private_data; 846 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 847 848 if (channel->align != 0) { 849#ifdef ALIGN_DEBUG 850 printf("unix_write_byte: O_DIRECT fallback\n"); 851#endif 852 return EXT2_ET_UNIMPLEMENTED; 853 } 854 855#ifndef NO_IO_CACHE 856 /* 857 * Flush out the cache completely 858 */ 859 if ((retval = flush_cached_blocks(channel, data, 1))) 860 return retval; 861#endif 862 863 if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0) 864 return errno; 865 866 actual = write(data->dev, buf, size); 867 if (actual != size) 868 return EXT2_ET_SHORT_WRITE; 869 870 return 0; 871} 872 873/* 874 * Flush data buffers to disk. 875 */ 876static errcode_t unix_flush(io_channel channel) 877{ 878 struct unix_private_data *data; 879 errcode_t retval = 0; 880 881 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 882 data = (struct unix_private_data *) channel->private_data; 883 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 884 885#ifndef NO_IO_CACHE 886 retval = flush_cached_blocks(channel, data, 0); 887#endif 888 fsync(data->dev); 889 return retval; 890} 891 892static errcode_t unix_set_option(io_channel channel, const char *option, 893 const char *arg) 894{ 895 struct unix_private_data *data; 896 unsigned long long tmp; 897 char *end; 898 899 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 900 data = (struct unix_private_data *) channel->private_data; 901 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 902 903 if (!strcmp(option, "offset")) { 904 if (!arg) 905 return EXT2_ET_INVALID_ARGUMENT; 906 907 tmp = strtoull(arg, &end, 0); 908 if (*end) 909 return EXT2_ET_INVALID_ARGUMENT; 910 data->offset = tmp; 911 if (data->offset < 0) 912 return EXT2_ET_INVALID_ARGUMENT; 913 return 0; 914 } 915 return EXT2_ET_INVALID_ARGUMENT; 916} 917 918#if defined(__linux__) && !defined(BLKDISCARD) 919#define BLKDISCARD _IO(0x12,119) 920#endif 921 922static errcode_t unix_discard(io_channel channel, unsigned long long block, 923 unsigned long long count) 924{ 925 struct unix_private_data *data; 926 int ret; 927 928 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 929 data = (struct unix_private_data *) channel->private_data; 930 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 931 932 if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) { 933#ifdef BLKDISCARD 934 __uint64_t range[2]; 935 936 range[0] = (__uint64_t)(block) * channel->block_size; 937 range[1] = (__uint64_t)(count) * channel->block_size; 938 939 ret = ioctl(data->dev, BLKDISCARD, &range); 940#else 941 goto unimplemented; 942#endif 943 } else { 944#if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE) 945 /* 946 * If we are not on block device, try to use punch hole 947 * to reclaim free space. 948 */ 949 ret = fallocate(data->dev, 950 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 951 (off_t)(block) * channel->block_size, 952 (off_t)(count) * channel->block_size); 953#else 954 goto unimplemented; 955#endif 956 } 957 if (ret < 0) { 958 if (errno == EOPNOTSUPP) 959 goto unimplemented; 960 return errno; 961 } 962 return 0; 963unimplemented: 964 return EXT2_ET_UNIMPLEMENTED; 965} 966