unix_io.c revision 4e0bb5eb745009decac4c5836671ff4bef21ce2a
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, zeroes = 0; 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 ioctl(data->dev, BLKDISCARDZEROES, &zeroes); 554 if (zeroes) 555 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES; 556#endif 557 558#if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) 559 /* 560 * Some operating systems require that the buffers be aligned, 561 * regardless of O_DIRECT 562 */ 563 if (!io->align) 564 io->align = 512; 565#endif 566 567 568 if ((retval = alloc_cache(io, data))) 569 goto cleanup; 570 571#ifdef BLKROGET 572 if (flags & IO_FLAG_RW) { 573 int error; 574 int readonly = 0; 575 576 /* Is the block device actually writable? */ 577 error = ioctl(data->dev, BLKROGET, &readonly); 578 if (!error && readonly) { 579 retval = EPERM; 580 goto cleanup; 581 } 582 } 583#endif 584 585#ifdef __linux__ 586#undef RLIM_INFINITY 587#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4))) 588#define RLIM_INFINITY ((unsigned long)(~0UL>>1)) 589#else 590#define RLIM_INFINITY (~0UL) 591#endif 592 /* 593 * Work around a bug in 2.4.10-2.4.18 kernels where writes to 594 * block devices are wrongly getting hit by the filesize 595 * limit. This workaround isn't perfect, since it won't work 596 * if glibc wasn't built against 2.2 header files. (Sigh.) 597 * 598 */ 599 if ((flags & IO_FLAG_RW) && 600 (uname(&ut) == 0) && 601 ((ut.release[0] == '2') && (ut.release[1] == '.') && 602 (ut.release[2] == '4') && (ut.release[3] == '.') && 603 (ut.release[4] == '1') && (ut.release[5] >= '0') && 604 (ut.release[5] < '8')) && 605 (ext2fs_stat(io->name, &st) == 0) && 606 (S_ISBLK(st.st_mode))) { 607 struct rlimit rlim; 608 609 rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY; 610 setrlimit(RLIMIT_FSIZE, &rlim); 611 getrlimit(RLIMIT_FSIZE, &rlim); 612 if (((unsigned long) rlim.rlim_cur) < 613 ((unsigned long) rlim.rlim_max)) { 614 rlim.rlim_cur = rlim.rlim_max; 615 setrlimit(RLIMIT_FSIZE, &rlim); 616 } 617 } 618#endif 619 *channel = io; 620 return 0; 621 622cleanup: 623 if (data) { 624 if (data->dev >= 0) 625 close(data->dev); 626 free_cache(data); 627 ext2fs_free_mem(&data); 628 } 629 if (io) { 630 if (io->name) { 631 ext2fs_free_mem(&io->name); 632 } 633 ext2fs_free_mem(&io); 634 } 635 return retval; 636} 637 638static errcode_t unix_close(io_channel channel) 639{ 640 struct unix_private_data *data; 641 errcode_t retval = 0; 642 643 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 644 data = (struct unix_private_data *) channel->private_data; 645 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 646 647 if (--channel->refcount > 0) 648 return 0; 649 650#ifndef NO_IO_CACHE 651 retval = flush_cached_blocks(channel, data, 0); 652#endif 653 654 if (close(data->dev) < 0) 655 retval = errno; 656 free_cache(data); 657 658 ext2fs_free_mem(&channel->private_data); 659 if (channel->name) 660 ext2fs_free_mem(&channel->name); 661 ext2fs_free_mem(&channel); 662 return retval; 663} 664 665static errcode_t unix_set_blksize(io_channel channel, int blksize) 666{ 667 struct unix_private_data *data; 668 errcode_t retval; 669 670 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 671 data = (struct unix_private_data *) channel->private_data; 672 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 673 674 if (channel->block_size != blksize) { 675#ifndef NO_IO_CACHE 676 if ((retval = flush_cached_blocks(channel, data, 0))) 677 return retval; 678#endif 679 680 channel->block_size = blksize; 681 free_cache(data); 682 if ((retval = alloc_cache(channel, data))) 683 return retval; 684 } 685 return 0; 686} 687 688 689static errcode_t unix_read_blk64(io_channel channel, unsigned long long block, 690 int count, void *buf) 691{ 692 struct unix_private_data *data; 693 struct unix_cache *cache, *reuse[READ_DIRECT_SIZE]; 694 errcode_t retval; 695 char *cp; 696 int i, j; 697 698 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 699 data = (struct unix_private_data *) channel->private_data; 700 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 701 702#ifdef NO_IO_CACHE 703 return raw_read_blk(channel, data, block, count, buf); 704#else 705 /* 706 * If we're doing an odd-sized read or a very large read, 707 * flush out the cache and then do a direct read. 708 */ 709 if (count < 0 || count > WRITE_DIRECT_SIZE) { 710 if ((retval = flush_cached_blocks(channel, data, 0))) 711 return retval; 712 return raw_read_blk(channel, data, block, count, buf); 713 } 714 715 cp = buf; 716 while (count > 0) { 717 /* If it's in the cache, use it! */ 718 if ((cache = find_cached_block(data, block, &reuse[0]))) { 719#ifdef DEBUG 720 printf("Using cached block %lu\n", block); 721#endif 722 memcpy(cp, cache->buf, channel->block_size); 723 count--; 724 block++; 725 cp += channel->block_size; 726 continue; 727 } 728 if (count == 1) { 729 /* 730 * Special case where we read directly into the 731 * cache buffer; important in the O_DIRECT case 732 */ 733 cache = reuse[0]; 734 reuse_cache(channel, data, cache, block); 735 if ((retval = raw_read_blk(channel, data, block, 1, 736 cache->buf))) { 737 cache->in_use = 0; 738 return retval; 739 } 740 memcpy(cp, cache->buf, channel->block_size); 741 return 0; 742 } 743 744 /* 745 * Find the number of uncached blocks so we can do a 746 * single read request 747 */ 748 for (i=1; i < count; i++) 749 if (find_cached_block(data, block+i, &reuse[i])) 750 break; 751#ifdef DEBUG 752 printf("Reading %d blocks starting at %lu\n", i, block); 753#endif 754 if ((retval = raw_read_blk(channel, data, block, i, cp))) 755 return retval; 756 757 /* Save the results in the cache */ 758 for (j=0; j < i; j++) { 759 count--; 760 cache = reuse[j]; 761 reuse_cache(channel, data, cache, block++); 762 memcpy(cache->buf, cp, channel->block_size); 763 cp += channel->block_size; 764 } 765 } 766 return 0; 767#endif /* NO_IO_CACHE */ 768} 769 770static errcode_t unix_read_blk(io_channel channel, unsigned long block, 771 int count, void *buf) 772{ 773 return unix_read_blk64(channel, block, count, buf); 774} 775 776static errcode_t unix_write_blk64(io_channel channel, unsigned long long block, 777 int count, const void *buf) 778{ 779 struct unix_private_data *data; 780 struct unix_cache *cache, *reuse; 781 errcode_t retval = 0; 782 const char *cp; 783 int writethrough; 784 785 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 786 data = (struct unix_private_data *) channel->private_data; 787 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 788 789#ifdef NO_IO_CACHE 790 return raw_write_blk(channel, data, block, count, buf); 791#else 792 /* 793 * If we're doing an odd-sized write or a very large write, 794 * flush out the cache completely and then do a direct write. 795 */ 796 if (count < 0 || count > WRITE_DIRECT_SIZE) { 797 if ((retval = flush_cached_blocks(channel, data, 1))) 798 return retval; 799 return raw_write_blk(channel, data, block, count, buf); 800 } 801 802 /* 803 * For a moderate-sized multi-block write, first force a write 804 * if we're in write-through cache mode, and then fill the 805 * cache with the blocks. 806 */ 807 writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH; 808 if (writethrough) 809 retval = raw_write_blk(channel, data, block, count, buf); 810 811 cp = buf; 812 while (count > 0) { 813 cache = find_cached_block(data, block, &reuse); 814 if (!cache) { 815 cache = reuse; 816 reuse_cache(channel, data, cache, block); 817 } 818 memcpy(cache->buf, cp, channel->block_size); 819 cache->dirty = !writethrough; 820 count--; 821 block++; 822 cp += channel->block_size; 823 } 824 return retval; 825#endif /* NO_IO_CACHE */ 826} 827 828static errcode_t unix_write_blk(io_channel channel, unsigned long block, 829 int count, const void *buf) 830{ 831 return unix_write_blk64(channel, block, count, buf); 832} 833 834static errcode_t unix_write_byte(io_channel channel, unsigned long offset, 835 int size, const void *buf) 836{ 837 struct unix_private_data *data; 838 errcode_t retval = 0; 839 ssize_t actual; 840 841 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 842 data = (struct unix_private_data *) channel->private_data; 843 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 844 845 if (channel->align != 0) { 846#ifdef ALIGN_DEBUG 847 printf("unix_write_byte: O_DIRECT fallback\n"); 848#endif 849 return EXT2_ET_UNIMPLEMENTED; 850 } 851 852#ifndef NO_IO_CACHE 853 /* 854 * Flush out the cache completely 855 */ 856 if ((retval = flush_cached_blocks(channel, data, 1))) 857 return retval; 858#endif 859 860 if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0) 861 return errno; 862 863 actual = write(data->dev, buf, size); 864 if (actual != size) 865 return EXT2_ET_SHORT_WRITE; 866 867 return 0; 868} 869 870/* 871 * Flush data buffers to disk. 872 */ 873static errcode_t unix_flush(io_channel channel) 874{ 875 struct unix_private_data *data; 876 errcode_t retval = 0; 877 878 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 879 data = (struct unix_private_data *) channel->private_data; 880 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 881 882#ifndef NO_IO_CACHE 883 retval = flush_cached_blocks(channel, data, 0); 884#endif 885 fsync(data->dev); 886 return retval; 887} 888 889static errcode_t unix_set_option(io_channel channel, const char *option, 890 const char *arg) 891{ 892 struct unix_private_data *data; 893 unsigned long long tmp; 894 char *end; 895 896 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 897 data = (struct unix_private_data *) channel->private_data; 898 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 899 900 if (!strcmp(option, "offset")) { 901 if (!arg) 902 return EXT2_ET_INVALID_ARGUMENT; 903 904 tmp = strtoull(arg, &end, 0); 905 if (*end) 906 return EXT2_ET_INVALID_ARGUMENT; 907 data->offset = tmp; 908 if (data->offset < 0) 909 return EXT2_ET_INVALID_ARGUMENT; 910 return 0; 911 } 912 return EXT2_ET_INVALID_ARGUMENT; 913} 914 915#if defined(__linux__) && !defined(BLKDISCARD) 916#define BLKDISCARD _IO(0x12,119) 917#endif 918 919static errcode_t unix_discard(io_channel channel, unsigned long long block, 920 unsigned long long count) 921{ 922 struct unix_private_data *data; 923 __uint64_t range[2]; 924 int ret; 925 926 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 927 data = (struct unix_private_data *) channel->private_data; 928 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 929 930 if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) { 931#ifdef BLKDISCARD 932 range[0] = (__uint64_t)(block) * channel->block_size; 933 range[1] = (__uint64_t)(count) * channel->block_size; 934 935 ret = ioctl(data->dev, BLKDISCARD, &range); 936#else 937 goto unimplemented; 938#endif 939 } else { 940#if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE) 941 /* 942 * If we are not on block device, try to use punch hole 943 * to reclaim free space. 944 */ 945 ret = fallocate(data->dev, 946 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 947 (off_t)(block) * channel->block_size, 948 (off_t)(count) * channel->block_size); 949#else 950 goto unimplemented; 951#endif 952 } 953 if (ret < 0) { 954 if (errno == EOPNOTSUPP) 955 goto unimplemented; 956 return errno; 957 } 958 return 0; 959unimplemented: 960 return EXT2_ET_UNIMPLEMENTED; 961} 962