unix_io.c revision d866599ab4955858b1541f0891b1b165ba66493a
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#define _GNU_SOURCE 21 22#include <stdio.h> 23#include <string.h> 24#if HAVE_UNISTD_H 25#include <unistd.h> 26#endif 27#if HAVE_ERRNO_H 28#include <errno.h> 29#endif 30#include <fcntl.h> 31#include <time.h> 32#ifdef __linux__ 33#include <sys/utsname.h> 34#endif 35#ifdef HAVE_SYS_IOCTL_H 36#include <sys/ioctl.h> 37#endif 38#ifdef HAVE_SYS_MOUNT_H 39#include <sys/mount.h> 40#endif 41#if HAVE_SYS_STAT_H 42#include <sys/stat.h> 43#endif 44#if HAVE_SYS_TYPES_H 45#include <sys/types.h> 46#endif 47#if HAVE_SYS_RESOURCE_H 48#include <sys/resource.h> 49#endif 50 51#if defined(__linux__) && defined(_IO) && !defined(BLKROGET) 52#define BLKROGET _IO(0x12, 94) /* Get read-only status (0 = read_write). */ 53#endif 54 55#if defined(__linux__) && defined(_IO) && !defined(BLKSSZGET) 56#define BLKSSZGET _IO(0x12,104)/* get block device sector size */ 57#endif 58 59#undef ALIGN_DEBUG 60 61#include "ext2_fs.h" 62#include "ext2fs.h" 63 64/* 65 * For checking structure magic numbers... 66 */ 67 68#define EXT2_CHECK_MAGIC(struct, code) \ 69 if ((struct)->magic != (code)) return (code) 70 71struct unix_cache { 72 char *buf; 73 unsigned long block; 74 int access_time; 75 unsigned dirty:1; 76 unsigned in_use:1; 77}; 78 79#define CACHE_SIZE 8 80#define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */ 81#define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */ 82 83struct unix_private_data { 84 int magic; 85 int dev; 86 int flags; 87 int align; 88 int access_time; 89 ext2_loff_t offset; 90 struct unix_cache cache[CACHE_SIZE]; 91 void *bounce; 92 struct struct_io_stats io_stats; 93}; 94 95#define IS_ALIGNED(n, align) ((((unsigned long) n) & \ 96 ((unsigned long) ((align)-1))) == 0) 97 98static errcode_t unix_open(const char *name, int flags, io_channel *channel); 99static errcode_t unix_close(io_channel channel); 100static errcode_t unix_set_blksize(io_channel channel, int blksize); 101static errcode_t unix_read_blk(io_channel channel, unsigned long block, 102 int count, void *data); 103static errcode_t unix_write_blk(io_channel channel, unsigned long block, 104 int count, const void *data); 105static errcode_t unix_flush(io_channel channel); 106static errcode_t unix_write_byte(io_channel channel, unsigned long offset, 107 int size, const void *data); 108static errcode_t unix_set_option(io_channel channel, const char *option, 109 const char *arg); 110static errcode_t unix_get_stats(io_channel channel, io_stats *stats) 111; 112static void reuse_cache(io_channel channel, struct unix_private_data *data, 113 struct unix_cache *cache, unsigned long long block); 114static errcode_t unix_read_blk64(io_channel channel, unsigned long long block, 115 int count, void *data); 116static errcode_t unix_write_blk64(io_channel channel, unsigned long long block, 117 int count, const void *data); 118static errcode_t unix_discard(io_channel channel, unsigned long long block, 119 unsigned long long count); 120 121static struct struct_io_manager struct_unix_manager = { 122 EXT2_ET_MAGIC_IO_MANAGER, 123 "Unix I/O Manager", 124 unix_open, 125 unix_close, 126 unix_set_blksize, 127 unix_read_blk, 128 unix_write_blk, 129 unix_flush, 130 unix_write_byte, 131 unix_set_option, 132 unix_get_stats, 133 unix_read_blk64, 134 unix_write_blk64, 135 unix_discard, 136}; 137 138io_manager unix_io_manager = &struct_unix_manager; 139 140static errcode_t unix_get_stats(io_channel channel, io_stats *stats) 141{ 142 errcode_t retval = 0; 143 144 struct unix_private_data *data; 145 146 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 147 data = (struct unix_private_data *) channel->private_data; 148 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 149 150 if (stats) 151 *stats = &data->io_stats; 152 153 return retval; 154} 155 156/* 157 * Here are the raw I/O functions 158 */ 159static errcode_t raw_read_blk(io_channel channel, 160 struct unix_private_data *data, 161 unsigned long long block, 162 int count, void *buf) 163{ 164 errcode_t retval; 165 ssize_t size; 166 ext2_loff_t location; 167 int actual = 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 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) { 173 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED; 174 goto error_out; 175 } 176 if ((data->align == 0) || 177 ((IS_ALIGNED(buf, data->align)) && IS_ALIGNED(size, data->align))) { 178 actual = read(data->dev, buf, size); 179 if (actual != size) { 180 short_read: 181 if (actual < 0) 182 actual = 0; 183 retval = EXT2_ET_SHORT_READ; 184 goto error_out; 185 } 186 return 0; 187 } 188 189#ifdef ALIGN_DEBUG 190 printf("raw_read_blk: O_DIRECT fallback: %p %lu\n", buf, 191 (unsigned long) size); 192#endif 193 194 /* 195 * The buffer or size which we're trying to read isn't aligned 196 * to the O_DIRECT rules, so we need to do this the hard way... 197 */ 198 while (size > 0) { 199 actual = read(data->dev, data->bounce, channel->block_size); 200 if (actual != channel->block_size) 201 goto short_read; 202 actual = size; 203 if (size > channel->block_size) 204 actual = channel->block_size; 205 memcpy(buf, data->bounce, actual); 206 size -= actual; 207 buf += actual; 208 } 209 return 0; 210 211error_out: 212 memset((char *) buf+actual, 0, size-actual); 213 if (channel->read_error) 214 retval = (channel->read_error)(channel, block, count, buf, 215 size, actual, retval); 216 return retval; 217} 218 219static errcode_t raw_write_blk(io_channel channel, 220 struct unix_private_data *data, 221 unsigned long long block, 222 int count, const void *buf) 223{ 224 ssize_t size; 225 ext2_loff_t location; 226 int actual = 0; 227 errcode_t retval; 228 229 if (count == 1) 230 size = channel->block_size; 231 else { 232 if (count < 0) 233 size = -count; 234 else 235 size = count * channel->block_size; 236 } 237 data->io_stats.bytes_written += size; 238 239 location = ((ext2_loff_t) block * channel->block_size) + data->offset; 240 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) { 241 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED; 242 goto error_out; 243 } 244 245 if ((data->align == 0) || 246 ((IS_ALIGNED(buf, data->align)) && IS_ALIGNED(size, data->align))) { 247 actual = write(data->dev, buf, size); 248 if (actual != size) { 249 short_write: 250 retval = EXT2_ET_SHORT_WRITE; 251 goto error_out; 252 } 253 return 0; 254 } 255 256#ifdef ALIGN_DEBUG 257 printf("raw_write_blk: O_DIRECT fallback: %p %lu\n", buf, 258 (unsigned long) size); 259#endif 260 /* 261 * The buffer or size which we're trying to write isn't aligned 262 * to the O_DIRECT rules, so we need to do this the hard way... 263 */ 264 while (size > 0) { 265 if (size < channel->block_size) { 266 actual = read(data->dev, data->bounce, 267 channel->block_size); 268 if (actual != channel->block_size) { 269 retval = EXT2_ET_SHORT_READ; 270 goto error_out; 271 } 272 } 273 actual = size; 274 if (size > channel->block_size) 275 actual = channel->block_size; 276 memcpy(data->bounce, buf, actual); 277 actual = write(data->dev, data->bounce, channel->block_size); 278 if (actual != channel->block_size) 279 goto short_write; 280 size -= actual; 281 buf += actual; 282 } 283 return 0; 284 285error_out: 286 if (channel->write_error) 287 retval = (channel->write_error)(channel, block, count, buf, 288 size, actual, retval); 289 return retval; 290} 291 292 293/* 294 * Here we implement the cache functions 295 */ 296 297/* Allocate the cache buffers */ 298static errcode_t alloc_cache(io_channel channel, 299 struct unix_private_data *data) 300{ 301 errcode_t retval; 302 struct unix_cache *cache; 303 int i; 304 305 data->access_time = 0; 306 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 307 cache->block = 0; 308 cache->access_time = 0; 309 cache->dirty = 0; 310 cache->in_use = 0; 311 if (cache->buf) 312 ext2fs_free_mem(&cache->buf); 313 retval = ext2fs_get_memalign(channel->block_size, 314 data->align, &cache->buf); 315 if (retval) 316 return retval; 317 } 318 if (data->align) { 319 if (data->bounce) 320 ext2fs_free_mem(&data->bounce); 321 retval = ext2fs_get_memalign(channel->block_size, data->align, 322 &data->bounce); 323 } 324 return retval; 325} 326 327/* Free the cache buffers */ 328static void free_cache(struct unix_private_data *data) 329{ 330 struct unix_cache *cache; 331 int i; 332 333 data->access_time = 0; 334 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 335 cache->block = 0; 336 cache->access_time = 0; 337 cache->dirty = 0; 338 cache->in_use = 0; 339 if (cache->buf) 340 ext2fs_free_mem(&cache->buf); 341 } 342 if (data->bounce) 343 ext2fs_free_mem(&data->bounce); 344} 345 346#ifndef NO_IO_CACHE 347/* 348 * Try to find a block in the cache. If the block is not found, and 349 * eldest is a non-zero pointer, then fill in eldest with the cache 350 * entry to that should be reused. 351 */ 352static struct unix_cache *find_cached_block(struct unix_private_data *data, 353 unsigned long long block, 354 struct unix_cache **eldest) 355{ 356 struct unix_cache *cache, *unused_cache, *oldest_cache; 357 int i; 358 359 unused_cache = oldest_cache = 0; 360 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 361 if (!cache->in_use) { 362 if (!unused_cache) 363 unused_cache = cache; 364 continue; 365 } 366 if (cache->block == block) { 367 cache->access_time = ++data->access_time; 368 return cache; 369 } 370 if (!oldest_cache || 371 (cache->access_time < oldest_cache->access_time)) 372 oldest_cache = cache; 373 } 374 if (eldest) 375 *eldest = (unused_cache) ? unused_cache : oldest_cache; 376 return 0; 377} 378 379/* 380 * Reuse a particular cache entry for another block. 381 */ 382static void reuse_cache(io_channel channel, struct unix_private_data *data, 383 struct unix_cache *cache, unsigned long long block) 384{ 385 if (cache->dirty && cache->in_use) 386 raw_write_blk(channel, data, cache->block, 1, cache->buf); 387 388 cache->in_use = 1; 389 cache->dirty = 0; 390 cache->block = block; 391 cache->access_time = ++data->access_time; 392} 393 394/* 395 * Flush all of the blocks in the cache 396 */ 397static errcode_t flush_cached_blocks(io_channel channel, 398 struct unix_private_data *data, 399 int invalidate) 400 401{ 402 struct unix_cache *cache; 403 errcode_t retval, retval2; 404 int i; 405 406 retval2 = 0; 407 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 408 if (!cache->in_use) 409 continue; 410 411 if (invalidate) 412 cache->in_use = 0; 413 414 if (!cache->dirty) 415 continue; 416 417 retval = raw_write_blk(channel, data, 418 cache->block, 1, cache->buf); 419 if (retval) 420 retval2 = retval; 421 else 422 cache->dirty = 0; 423 } 424 return retval2; 425} 426#endif /* NO_IO_CACHE */ 427 428#ifdef __linux__ 429#ifndef BLKDISCARDZEROES 430#define BLKDISCARDZEROES _IO(0x12,124) 431#endif 432#endif 433 434static errcode_t unix_open(const char *name, int flags, io_channel *channel) 435{ 436 io_channel io = NULL; 437 struct unix_private_data *data = NULL; 438 errcode_t retval; 439 int open_flags, zeroes = 0; 440 struct stat st; 441#ifdef __linux__ 442 struct utsname ut; 443#endif 444 445 if (name == 0) 446 return EXT2_ET_BAD_DEVICE_NAME; 447 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io); 448 if (retval) 449 return retval; 450 memset(io, 0, sizeof(struct struct_io_channel)); 451 io->magic = EXT2_ET_MAGIC_IO_CHANNEL; 452 retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data); 453 if (retval) 454 goto cleanup; 455 456 io->manager = unix_io_manager; 457 retval = ext2fs_get_mem(strlen(name)+1, &io->name); 458 if (retval) 459 goto cleanup; 460 461 strcpy(io->name, name); 462 io->private_data = data; 463 io->block_size = 1024; 464 io->read_error = 0; 465 io->write_error = 0; 466 io->refcount = 1; 467 468 memset(data, 0, sizeof(struct unix_private_data)); 469 data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL; 470 data->io_stats.num_fields = 2; 471 472 open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY; 473 if (flags & IO_FLAG_EXCLUSIVE) 474 open_flags |= O_EXCL; 475 if (flags & IO_FLAG_DIRECT_IO) 476 open_flags |= O_DIRECT; 477 data->flags = flags; 478 479#ifdef HAVE_OPEN64 480 data->dev = open64(io->name, open_flags); 481#else 482 data->dev = open(io->name, open_flags); 483#endif 484 if (data->dev < 0) { 485 retval = errno; 486 goto cleanup; 487 } 488 489#ifdef BLKSSZGET 490 if (flags & IO_FLAG_DIRECT_IO) { 491 if (ioctl(data->dev, BLKSSZGET, &data->align) != 0) 492 data->align = io->block_size; 493 } 494#endif 495 496#ifdef BLKDISCARDZEROES 497 ioctl(data->dev, BLKDISCARDZEROES, &zeroes); 498 if (zeroes) 499 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES; 500#endif 501 502#if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) 503 /* 504 * Some operating systems require that the buffers be aligned, 505 * regardless of O_DIRECT 506 */ 507 data->align = 512; 508#endif 509 510 511 if ((retval = alloc_cache(io, data))) 512 goto cleanup; 513 514#ifdef BLKROGET 515 if (flags & IO_FLAG_RW) { 516 int error; 517 int readonly = 0; 518 519 /* Is the block device actually writable? */ 520 error = ioctl(data->dev, BLKROGET, &readonly); 521 if (!error && readonly) { 522 close(data->dev); 523 retval = EPERM; 524 goto cleanup; 525 } 526 } 527#endif 528 529#ifdef __linux__ 530#undef RLIM_INFINITY 531#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4))) 532#define RLIM_INFINITY ((unsigned long)(~0UL>>1)) 533#else 534#define RLIM_INFINITY (~0UL) 535#endif 536 /* 537 * Work around a bug in 2.4.10-2.4.18 kernels where writes to 538 * block devices are wrongly getting hit by the filesize 539 * limit. This workaround isn't perfect, since it won't work 540 * if glibc wasn't built against 2.2 header files. (Sigh.) 541 * 542 */ 543 if ((flags & IO_FLAG_RW) && 544 (uname(&ut) == 0) && 545 ((ut.release[0] == '2') && (ut.release[1] == '.') && 546 (ut.release[2] == '4') && (ut.release[3] == '.') && 547 (ut.release[4] == '1') && (ut.release[5] >= '0') && 548 (ut.release[5] < '8')) && 549 (fstat(data->dev, &st) == 0) && 550 (S_ISBLK(st.st_mode))) { 551 struct rlimit rlim; 552 553 rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY; 554 setrlimit(RLIMIT_FSIZE, &rlim); 555 getrlimit(RLIMIT_FSIZE, &rlim); 556 if (((unsigned long) rlim.rlim_cur) < 557 ((unsigned long) rlim.rlim_max)) { 558 rlim.rlim_cur = rlim.rlim_max; 559 setrlimit(RLIMIT_FSIZE, &rlim); 560 } 561 } 562#endif 563 *channel = io; 564 return 0; 565 566cleanup: 567 if (data) { 568 free_cache(data); 569 ext2fs_free_mem(&data); 570 } 571 if (io) 572 ext2fs_free_mem(&io); 573 return retval; 574} 575 576static errcode_t unix_close(io_channel channel) 577{ 578 struct unix_private_data *data; 579 errcode_t retval = 0; 580 581 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 582 data = (struct unix_private_data *) channel->private_data; 583 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 584 585 if (--channel->refcount > 0) 586 return 0; 587 588#ifndef NO_IO_CACHE 589 retval = flush_cached_blocks(channel, data, 0); 590#endif 591 592 if (close(data->dev) < 0) 593 retval = errno; 594 free_cache(data); 595 596 ext2fs_free_mem(&channel->private_data); 597 if (channel->name) 598 ext2fs_free_mem(&channel->name); 599 ext2fs_free_mem(&channel); 600 return retval; 601} 602 603static errcode_t unix_set_blksize(io_channel channel, int blksize) 604{ 605 struct unix_private_data *data; 606 errcode_t retval; 607 608 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 609 data = (struct unix_private_data *) channel->private_data; 610 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 611 612 if (channel->block_size != blksize) { 613#ifndef NO_IO_CACHE 614 if ((retval = flush_cached_blocks(channel, data, 0))) 615 return retval; 616#endif 617 618 channel->block_size = blksize; 619 free_cache(data); 620 if ((retval = alloc_cache(channel, data))) 621 return retval; 622 } 623 return 0; 624} 625 626 627static errcode_t unix_read_blk64(io_channel channel, unsigned long long block, 628 int count, void *buf) 629{ 630 struct unix_private_data *data; 631 struct unix_cache *cache, *reuse[READ_DIRECT_SIZE]; 632 errcode_t retval; 633 char *cp; 634 int i, j; 635 636 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 637 data = (struct unix_private_data *) channel->private_data; 638 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 639 640#ifdef NO_IO_CACHE 641 return raw_read_blk(channel, data, block, count, buf); 642#else 643 /* 644 * If we're doing an odd-sized read or a very large read, 645 * flush out the cache and then do a direct read. 646 */ 647 if (count < 0 || count > WRITE_DIRECT_SIZE) { 648 if ((retval = flush_cached_blocks(channel, data, 0))) 649 return retval; 650 return raw_read_blk(channel, data, block, count, buf); 651 } 652 653 cp = buf; 654 while (count > 0) { 655 /* If it's in the cache, use it! */ 656 if ((cache = find_cached_block(data, block, &reuse[0]))) { 657#ifdef DEBUG 658 printf("Using cached block %lu\n", block); 659#endif 660 memcpy(cp, cache->buf, channel->block_size); 661 count--; 662 block++; 663 cp += channel->block_size; 664 continue; 665 } 666 if (count == 1) { 667 /* 668 * Special case where we read directly into the 669 * cache buffer; important in the O_DIRECT case 670 */ 671 cache = reuse[0]; 672 reuse_cache(channel, data, cache, block); 673 if ((retval = raw_read_blk(channel, data, block, 1, 674 cache->buf))) { 675 cache->in_use = 0; 676 return retval; 677 } 678 memcpy(cp, cache->buf, channel->block_size); 679 return 0; 680 } 681 682 /* 683 * Find the number of uncached blocks so we can do a 684 * single read request 685 */ 686 for (i=1; i < count; i++) 687 if (find_cached_block(data, block+i, &reuse[i])) 688 break; 689#ifdef DEBUG 690 printf("Reading %d blocks starting at %lu\n", i, block); 691#endif 692 if ((retval = raw_read_blk(channel, data, block, i, cp))) 693 return retval; 694 695 /* Save the results in the cache */ 696 for (j=0; j < i; j++) { 697 count--; 698 cache = reuse[j]; 699 reuse_cache(channel, data, cache, block++); 700 memcpy(cache->buf, cp, channel->block_size); 701 cp += channel->block_size; 702 } 703 } 704 return 0; 705#endif /* NO_IO_CACHE */ 706} 707 708static errcode_t unix_read_blk(io_channel channel, unsigned long block, 709 int count, void *buf) 710{ 711 return unix_read_blk64(channel, block, count, buf); 712} 713 714static errcode_t unix_write_blk64(io_channel channel, unsigned long long block, 715 int count, const void *buf) 716{ 717 struct unix_private_data *data; 718 struct unix_cache *cache, *reuse; 719 errcode_t retval = 0; 720 const char *cp; 721 int writethrough; 722 723 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 724 data = (struct unix_private_data *) channel->private_data; 725 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 726 727#ifdef NO_IO_CACHE 728 return raw_write_blk(channel, data, block, count, buf); 729#else 730 /* 731 * If we're doing an odd-sized write or a very large write, 732 * flush out the cache completely and then do a direct write. 733 */ 734 if (count < 0 || count > WRITE_DIRECT_SIZE) { 735 if ((retval = flush_cached_blocks(channel, data, 1))) 736 return retval; 737 return raw_write_blk(channel, data, block, count, buf); 738 } 739 740 /* 741 * For a moderate-sized multi-block write, first force a write 742 * if we're in write-through cache mode, and then fill the 743 * cache with the blocks. 744 */ 745 writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH; 746 if (writethrough) 747 retval = raw_write_blk(channel, data, block, count, buf); 748 749 cp = buf; 750 while (count > 0) { 751 cache = find_cached_block(data, block, &reuse); 752 if (!cache) { 753 cache = reuse; 754 reuse_cache(channel, data, cache, block); 755 } 756 memcpy(cache->buf, cp, channel->block_size); 757 cache->dirty = !writethrough; 758 count--; 759 block++; 760 cp += channel->block_size; 761 } 762 return retval; 763#endif /* NO_IO_CACHE */ 764} 765 766static errcode_t unix_write_blk(io_channel channel, unsigned long block, 767 int count, const void *buf) 768{ 769 return unix_write_blk64(channel, block, count, buf); 770} 771 772static errcode_t unix_write_byte(io_channel channel, unsigned long offset, 773 int size, const void *buf) 774{ 775 struct unix_private_data *data; 776 errcode_t retval = 0; 777 ssize_t actual; 778 779 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 780 data = (struct unix_private_data *) channel->private_data; 781 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 782 783 if (data->align != 0) { 784#ifdef ALIGN_DEBUG 785 printf("unix_write_byte: O_DIRECT fallback\n"); 786#endif 787 return EXT2_ET_UNIMPLEMENTED; 788 } 789 790#ifndef NO_IO_CACHE 791 /* 792 * Flush out the cache completely 793 */ 794 if ((retval = flush_cached_blocks(channel, data, 1))) 795 return retval; 796#endif 797 798 if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0) 799 return errno; 800 801 actual = write(data->dev, buf, size); 802 if (actual != size) 803 return EXT2_ET_SHORT_WRITE; 804 805 return 0; 806} 807 808/* 809 * Flush data buffers to disk. 810 */ 811static errcode_t unix_flush(io_channel channel) 812{ 813 struct unix_private_data *data; 814 errcode_t retval = 0; 815 816 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 817 data = (struct unix_private_data *) channel->private_data; 818 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 819 820#ifndef NO_IO_CACHE 821 retval = flush_cached_blocks(channel, data, 0); 822#endif 823 fsync(data->dev); 824 return retval; 825} 826 827static errcode_t unix_set_option(io_channel channel, const char *option, 828 const char *arg) 829{ 830 struct unix_private_data *data; 831 unsigned long long tmp; 832 char *end; 833 834 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 835 data = (struct unix_private_data *) channel->private_data; 836 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 837 838 if (!strcmp(option, "offset")) { 839 if (!arg) 840 return EXT2_ET_INVALID_ARGUMENT; 841 842 tmp = strtoull(arg, &end, 0); 843 if (*end) 844 return EXT2_ET_INVALID_ARGUMENT; 845 data->offset = tmp; 846 if (data->offset < 0) 847 return EXT2_ET_INVALID_ARGUMENT; 848 return 0; 849 } 850 return EXT2_ET_INVALID_ARGUMENT; 851} 852 853#if defined(__linux__) && !defined(BLKDISCARD) 854#define BLKDISCARD _IO(0x12,119) 855#endif 856 857static errcode_t unix_discard(io_channel channel, unsigned long long block, 858 unsigned long long count) 859{ 860#ifdef BLKDISCARD 861 struct unix_private_data *data; 862 __uint64_t range[2]; 863 int ret; 864 865 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 866 data = (struct unix_private_data *) channel->private_data; 867 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 868 869 range[0] = (__uint64_t)(block) * channel->block_size; 870 range[1] = (__uint64_t)(count) * channel->block_size; 871 872 ret = ioctl(data->dev, BLKDISCARD, &range); 873 if (ret < 0) 874 return errno; 875 return 0; 876#else 877 return EXT2_ET_UNIMPLEMENTED; 878#endif 879} 880