unix_io.c revision c859cb1de0d624caa0779fb17d1a53766143136e
1/* 2 * unix_io.c --- This is the Unix (well, really POSIX) implementation 3 * of the I/O manager. 4 * 5 * Implements a one-block write-through cache. 6 * 7 * Includes support for Windows NT support under Cygwin. 8 * 9 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 10 * 2002 by Theodore Ts'o. 11 * 12 * %Begin-Header% 13 * This file may be redistributed under the terms of the GNU Library 14 * General Public License, version 2. 15 * %End-Header% 16 */ 17 18#define _LARGEFILE_SOURCE 19#define _LARGEFILE64_SOURCE 20#ifndef _GNU_SOURCE 21#define _GNU_SOURCE 22#endif 23 24#include <stdio.h> 25#include <string.h> 26#if HAVE_UNISTD_H 27#include <unistd.h> 28#endif 29#if HAVE_ERRNO_H 30#include <errno.h> 31#endif 32#include <fcntl.h> 33#include <time.h> 34#ifdef __linux__ 35#include <sys/utsname.h> 36#endif 37#ifdef HAVE_SYS_IOCTL_H 38#include <sys/ioctl.h> 39#endif 40#ifdef HAVE_SYS_MOUNT_H 41#include <sys/mount.h> 42#endif 43#if HAVE_SYS_STAT_H 44#include <sys/stat.h> 45#endif 46#if HAVE_SYS_TYPES_H 47#include <sys/types.h> 48#endif 49#if HAVE_SYS_RESOURCE_H 50#include <sys/resource.h> 51#endif 52 53#if defined(__linux__) && defined(_IO) && !defined(BLKROGET) 54#define BLKROGET _IO(0x12, 94) /* Get read-only status (0 = read_write). */ 55#endif 56 57#if defined(__linux__) && defined(_IO) && !defined(BLKSSZGET) 58#define BLKSSZGET _IO(0x12,104)/* get block device sector size */ 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 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 ((data->align == 0) || 180 ((IS_ALIGNED(buf, data->align)) && IS_ALIGNED(size, data->align))) { 181 actual = read(data->dev, buf, size); 182 if (actual != size) { 183 short_read: 184 if (actual < 0) 185 actual = 0; 186 retval = EXT2_ET_SHORT_READ; 187 goto error_out; 188 } 189 return 0; 190 } 191 192#ifdef ALIGN_DEBUG 193 printf("raw_read_blk: O_DIRECT fallback: %p %lu\n", buf, 194 (unsigned long) size); 195#endif 196 197 /* 198 * The buffer or size which we're trying to read isn't aligned 199 * to the O_DIRECT rules, so we need to do this the hard way... 200 */ 201 while (size > 0) { 202 actual = read(data->dev, data->bounce, channel->block_size); 203 if (actual != channel->block_size) 204 goto short_read; 205 actual = size; 206 if (size > channel->block_size) 207 actual = channel->block_size; 208 memcpy(buf, data->bounce, actual); 209 size -= actual; 210 buf += actual; 211 } 212 return 0; 213 214error_out: 215 memset((char *) buf+actual, 0, size-actual); 216 if (channel->read_error) 217 retval = (channel->read_error)(channel, block, count, buf, 218 size, actual, retval); 219 return retval; 220} 221 222static errcode_t raw_write_blk(io_channel channel, 223 struct unix_private_data *data, 224 unsigned long long block, 225 int count, const void *bufv) 226{ 227 ssize_t size; 228 ext2_loff_t location; 229 int actual = 0; 230 errcode_t retval; 231 const unsigned char *buf = bufv; 232 233 if (count == 1) 234 size = channel->block_size; 235 else { 236 if (count < 0) 237 size = -count; 238 else 239 size = count * channel->block_size; 240 } 241 data->io_stats.bytes_written += size; 242 243 location = ((ext2_loff_t) block * channel->block_size) + data->offset; 244 if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) { 245 retval = errno ? errno : EXT2_ET_LLSEEK_FAILED; 246 goto error_out; 247 } 248 249 if ((data->align == 0) || 250 ((IS_ALIGNED(buf, data->align)) && IS_ALIGNED(size, data->align))) { 251 actual = write(data->dev, buf, size); 252 if (actual != size) { 253 short_write: 254 retval = EXT2_ET_SHORT_WRITE; 255 goto error_out; 256 } 257 return 0; 258 } 259 260#ifdef ALIGN_DEBUG 261 printf("raw_write_blk: O_DIRECT fallback: %p %lu\n", buf, 262 (unsigned long) size); 263#endif 264 /* 265 * The buffer or size which we're trying to write isn't aligned 266 * to the O_DIRECT rules, so we need to do this the hard way... 267 */ 268 while (size > 0) { 269 if (size < channel->block_size) { 270 actual = read(data->dev, data->bounce, 271 channel->block_size); 272 if (actual != channel->block_size) { 273 retval = EXT2_ET_SHORT_READ; 274 goto error_out; 275 } 276 } 277 actual = size; 278 if (size > channel->block_size) 279 actual = channel->block_size; 280 memcpy(data->bounce, buf, actual); 281 actual = write(data->dev, data->bounce, channel->block_size); 282 if (actual != channel->block_size) 283 goto short_write; 284 size -= actual; 285 buf += actual; 286 } 287 return 0; 288 289error_out: 290 if (channel->write_error) 291 retval = (channel->write_error)(channel, block, count, buf, 292 size, actual, retval); 293 return retval; 294} 295 296 297/* 298 * Here we implement the cache functions 299 */ 300 301/* Allocate the cache buffers */ 302static errcode_t alloc_cache(io_channel channel, 303 struct unix_private_data *data) 304{ 305 errcode_t retval; 306 struct unix_cache *cache; 307 int i; 308 309 data->access_time = 0; 310 for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) { 311 cache->block = 0; 312 cache->access_time = 0; 313 cache->dirty = 0; 314 cache->in_use = 0; 315 if (cache->buf) 316 ext2fs_free_mem(&cache->buf); 317 retval = ext2fs_get_memalign(channel->block_size, 318 data->align, &cache->buf); 319 if (retval) 320 return retval; 321 } 322 if (data->align) { 323 if (data->bounce) 324 ext2fs_free_mem(&data->bounce); 325 retval = ext2fs_get_memalign(channel->block_size, data->align, 326 &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 438static errcode_t unix_open(const char *name, int flags, io_channel *channel) 439{ 440 io_channel io = NULL; 441 struct unix_private_data *data = NULL; 442 errcode_t retval; 443 int open_flags, zeroes = 0; 444 ext2fs_struct_stat st; 445#ifdef __linux__ 446 struct utsname ut; 447#endif 448 449 if (name == 0) 450 return EXT2_ET_BAD_DEVICE_NAME; 451 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io); 452 if (retval) 453 return retval; 454 memset(io, 0, sizeof(struct struct_io_channel)); 455 io->magic = EXT2_ET_MAGIC_IO_CHANNEL; 456 retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data); 457 if (retval) 458 goto cleanup; 459 460 io->manager = unix_io_manager; 461 retval = ext2fs_get_mem(strlen(name)+1, &io->name); 462 if (retval) 463 goto cleanup; 464 465 strcpy(io->name, name); 466 io->private_data = data; 467 io->block_size = 1024; 468 io->read_error = 0; 469 io->write_error = 0; 470 io->refcount = 1; 471 472 memset(data, 0, sizeof(struct unix_private_data)); 473 data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL; 474 data->io_stats.num_fields = 2; 475 476 open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY; 477 if (flags & IO_FLAG_EXCLUSIVE) 478 open_flags |= O_EXCL; 479#ifdef O_DIRECT 480 if (flags & IO_FLAG_DIRECT_IO) 481 open_flags |= O_DIRECT; 482#endif 483 data->flags = flags; 484 485 data->dev = ext2fs_open_file(io->name, open_flags); 486 if (data->dev < 0) { 487 retval = errno; 488 goto cleanup; 489 } 490 491#ifdef BLKSSZGET 492 if (flags & IO_FLAG_DIRECT_IO) { 493 if (ioctl(data->dev, BLKSSZGET, &data->align) != 0) 494 data->align = io->block_size; 495 } 496#endif 497 498#ifdef BLKDISCARDZEROES 499 ioctl(data->dev, BLKDISCARDZEROES, &zeroes); 500 if (zeroes) 501 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES; 502#endif 503 504#if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) 505 /* 506 * Some operating systems require that the buffers be aligned, 507 * regardless of O_DIRECT 508 */ 509 data->align = 512; 510#endif 511 512 513 if ((retval = alloc_cache(io, data))) 514 goto cleanup; 515 516#ifdef BLKROGET 517 if (flags & IO_FLAG_RW) { 518 int error; 519 int readonly = 0; 520 521 /* Is the block device actually writable? */ 522 error = ioctl(data->dev, BLKROGET, &readonly); 523 if (!error && readonly) { 524 close(data->dev); 525 retval = EPERM; 526 goto cleanup; 527 } 528 } 529#endif 530 531#ifdef __linux__ 532#undef RLIM_INFINITY 533#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4))) 534#define RLIM_INFINITY ((unsigned long)(~0UL>>1)) 535#else 536#define RLIM_INFINITY (~0UL) 537#endif 538 /* 539 * Work around a bug in 2.4.10-2.4.18 kernels where writes to 540 * block devices are wrongly getting hit by the filesize 541 * limit. This workaround isn't perfect, since it won't work 542 * if glibc wasn't built against 2.2 header files. (Sigh.) 543 * 544 */ 545 if ((flags & IO_FLAG_RW) && 546 (uname(&ut) == 0) && 547 ((ut.release[0] == '2') && (ut.release[1] == '.') && 548 (ut.release[2] == '4') && (ut.release[3] == '.') && 549 (ut.release[4] == '1') && (ut.release[5] >= '0') && 550 (ut.release[5] < '8')) && 551 (ext2fs_stat(io->name, &st) == 0) && 552 (S_ISBLK(st.st_mode))) { 553 struct rlimit rlim; 554 555 rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY; 556 setrlimit(RLIMIT_FSIZE, &rlim); 557 getrlimit(RLIMIT_FSIZE, &rlim); 558 if (((unsigned long) rlim.rlim_cur) < 559 ((unsigned long) rlim.rlim_max)) { 560 rlim.rlim_cur = rlim.rlim_max; 561 setrlimit(RLIMIT_FSIZE, &rlim); 562 } 563 } 564#endif 565 *channel = io; 566 return 0; 567 568cleanup: 569 if (data) { 570 free_cache(data); 571 ext2fs_free_mem(&data); 572 } 573 if (io) 574 ext2fs_free_mem(&io); 575 return retval; 576} 577 578static errcode_t unix_close(io_channel channel) 579{ 580 struct unix_private_data *data; 581 errcode_t retval = 0; 582 583 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 584 data = (struct unix_private_data *) channel->private_data; 585 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 586 587 if (--channel->refcount > 0) 588 return 0; 589 590#ifndef NO_IO_CACHE 591 retval = flush_cached_blocks(channel, data, 0); 592#endif 593 594 if (close(data->dev) < 0) 595 retval = errno; 596 free_cache(data); 597 598 ext2fs_free_mem(&channel->private_data); 599 if (channel->name) 600 ext2fs_free_mem(&channel->name); 601 ext2fs_free_mem(&channel); 602 return retval; 603} 604 605static errcode_t unix_set_blksize(io_channel channel, int blksize) 606{ 607 struct unix_private_data *data; 608 errcode_t retval; 609 610 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 611 data = (struct unix_private_data *) channel->private_data; 612 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 613 614 if (channel->block_size != blksize) { 615#ifndef NO_IO_CACHE 616 if ((retval = flush_cached_blocks(channel, data, 0))) 617 return retval; 618#endif 619 620 channel->block_size = blksize; 621 free_cache(data); 622 if ((retval = alloc_cache(channel, data))) 623 return retval; 624 } 625 return 0; 626} 627 628 629static errcode_t unix_read_blk64(io_channel channel, unsigned long long block, 630 int count, void *buf) 631{ 632 struct unix_private_data *data; 633 struct unix_cache *cache, *reuse[READ_DIRECT_SIZE]; 634 errcode_t retval; 635 char *cp; 636 int i, j; 637 638 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 639 data = (struct unix_private_data *) channel->private_data; 640 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 641 642#ifdef NO_IO_CACHE 643 return raw_read_blk(channel, data, block, count, buf); 644#else 645 /* 646 * If we're doing an odd-sized read or a very large read, 647 * flush out the cache and then do a direct read. 648 */ 649 if (count < 0 || count > WRITE_DIRECT_SIZE) { 650 if ((retval = flush_cached_blocks(channel, data, 0))) 651 return retval; 652 return raw_read_blk(channel, data, block, count, buf); 653 } 654 655 cp = buf; 656 while (count > 0) { 657 /* If it's in the cache, use it! */ 658 if ((cache = find_cached_block(data, block, &reuse[0]))) { 659#ifdef DEBUG 660 printf("Using cached block %lu\n", block); 661#endif 662 memcpy(cp, cache->buf, channel->block_size); 663 count--; 664 block++; 665 cp += channel->block_size; 666 continue; 667 } 668 if (count == 1) { 669 /* 670 * Special case where we read directly into the 671 * cache buffer; important in the O_DIRECT case 672 */ 673 cache = reuse[0]; 674 reuse_cache(channel, data, cache, block); 675 if ((retval = raw_read_blk(channel, data, block, 1, 676 cache->buf))) { 677 cache->in_use = 0; 678 return retval; 679 } 680 memcpy(cp, cache->buf, channel->block_size); 681 return 0; 682 } 683 684 /* 685 * Find the number of uncached blocks so we can do a 686 * single read request 687 */ 688 for (i=1; i < count; i++) 689 if (find_cached_block(data, block+i, &reuse[i])) 690 break; 691#ifdef DEBUG 692 printf("Reading %d blocks starting at %lu\n", i, block); 693#endif 694 if ((retval = raw_read_blk(channel, data, block, i, cp))) 695 return retval; 696 697 /* Save the results in the cache */ 698 for (j=0; j < i; j++) { 699 count--; 700 cache = reuse[j]; 701 reuse_cache(channel, data, cache, block++); 702 memcpy(cache->buf, cp, channel->block_size); 703 cp += channel->block_size; 704 } 705 } 706 return 0; 707#endif /* NO_IO_CACHE */ 708} 709 710static errcode_t unix_read_blk(io_channel channel, unsigned long block, 711 int count, void *buf) 712{ 713 return unix_read_blk64(channel, block, count, buf); 714} 715 716static errcode_t unix_write_blk64(io_channel channel, unsigned long long block, 717 int count, const void *buf) 718{ 719 struct unix_private_data *data; 720 struct unix_cache *cache, *reuse; 721 errcode_t retval = 0; 722 const char *cp; 723 int writethrough; 724 725 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 726 data = (struct unix_private_data *) channel->private_data; 727 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 728 729#ifdef NO_IO_CACHE 730 return raw_write_blk(channel, data, block, count, buf); 731#else 732 /* 733 * If we're doing an odd-sized write or a very large write, 734 * flush out the cache completely and then do a direct write. 735 */ 736 if (count < 0 || count > WRITE_DIRECT_SIZE) { 737 if ((retval = flush_cached_blocks(channel, data, 1))) 738 return retval; 739 return raw_write_blk(channel, data, block, count, buf); 740 } 741 742 /* 743 * For a moderate-sized multi-block write, first force a write 744 * if we're in write-through cache mode, and then fill the 745 * cache with the blocks. 746 */ 747 writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH; 748 if (writethrough) 749 retval = raw_write_blk(channel, data, block, count, buf); 750 751 cp = buf; 752 while (count > 0) { 753 cache = find_cached_block(data, block, &reuse); 754 if (!cache) { 755 cache = reuse; 756 reuse_cache(channel, data, cache, block); 757 } 758 memcpy(cache->buf, cp, channel->block_size); 759 cache->dirty = !writethrough; 760 count--; 761 block++; 762 cp += channel->block_size; 763 } 764 return retval; 765#endif /* NO_IO_CACHE */ 766} 767 768static errcode_t unix_write_blk(io_channel channel, unsigned long block, 769 int count, const void *buf) 770{ 771 return unix_write_blk64(channel, block, count, buf); 772} 773 774static errcode_t unix_write_byte(io_channel channel, unsigned long offset, 775 int size, const void *buf) 776{ 777 struct unix_private_data *data; 778 errcode_t retval = 0; 779 ssize_t actual; 780 781 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 782 data = (struct unix_private_data *) channel->private_data; 783 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 784 785 if (data->align != 0) { 786#ifdef ALIGN_DEBUG 787 printf("unix_write_byte: O_DIRECT fallback\n"); 788#endif 789 return EXT2_ET_UNIMPLEMENTED; 790 } 791 792#ifndef NO_IO_CACHE 793 /* 794 * Flush out the cache completely 795 */ 796 if ((retval = flush_cached_blocks(channel, data, 1))) 797 return retval; 798#endif 799 800 if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0) 801 return errno; 802 803 actual = write(data->dev, buf, size); 804 if (actual != size) 805 return EXT2_ET_SHORT_WRITE; 806 807 return 0; 808} 809 810/* 811 * Flush data buffers to disk. 812 */ 813static errcode_t unix_flush(io_channel channel) 814{ 815 struct unix_private_data *data; 816 errcode_t retval = 0; 817 818 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 819 data = (struct unix_private_data *) channel->private_data; 820 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 821 822#ifndef NO_IO_CACHE 823 retval = flush_cached_blocks(channel, data, 0); 824#endif 825 fsync(data->dev); 826 return retval; 827} 828 829static errcode_t unix_set_option(io_channel channel, const char *option, 830 const char *arg) 831{ 832 struct unix_private_data *data; 833 unsigned long long tmp; 834 char *end; 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 if (!strcmp(option, "offset")) { 841 if (!arg) 842 return EXT2_ET_INVALID_ARGUMENT; 843 844 tmp = strtoull(arg, &end, 0); 845 if (*end) 846 return EXT2_ET_INVALID_ARGUMENT; 847 data->offset = tmp; 848 if (data->offset < 0) 849 return EXT2_ET_INVALID_ARGUMENT; 850 return 0; 851 } 852 return EXT2_ET_INVALID_ARGUMENT; 853} 854 855#if defined(__linux__) && !defined(BLKDISCARD) 856#define BLKDISCARD _IO(0x12,119) 857#endif 858 859static errcode_t unix_discard(io_channel channel, unsigned long long block, 860 unsigned long long count) 861{ 862#ifdef BLKDISCARD 863 struct unix_private_data *data; 864 __uint64_t range[2]; 865 int ret; 866 867 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 868 data = (struct unix_private_data *) channel->private_data; 869 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 870 871 range[0] = (__uint64_t)(block) * channel->block_size; 872 range[1] = (__uint64_t)(count) * channel->block_size; 873 874 ret = ioctl(data->dev, BLKDISCARD, &range); 875 if (ret < 0) 876 return errno; 877 return 0; 878#else 879 return EXT2_ET_UNIMPLEMENTED; 880#endif 881} 882