unix_io.c revision fd1c5a0622a9578b86f695d2f60df7d4f8b21875
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 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 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 int f_nocache = 0; 445 ext2fs_struct_stat st; 446#ifdef __linux__ 447 struct utsname ut; 448#endif 449 450 if (name == 0) 451 return EXT2_ET_BAD_DEVICE_NAME; 452 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io); 453 if (retval) 454 goto cleanup; 455 memset(io, 0, sizeof(struct struct_io_channel)); 456 io->magic = EXT2_ET_MAGIC_IO_CHANNEL; 457 retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data); 458 if (retval) 459 goto cleanup; 460 461 io->manager = unix_io_manager; 462 retval = ext2fs_get_mem(strlen(name)+1, &io->name); 463 if (retval) 464 goto cleanup; 465 466 strcpy(io->name, name); 467 io->private_data = data; 468 io->block_size = 1024; 469 io->read_error = 0; 470 io->write_error = 0; 471 io->refcount = 1; 472 473 memset(data, 0, sizeof(struct unix_private_data)); 474 data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL; 475 data->io_stats.num_fields = 2; 476 477 open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY; 478 if (flags & IO_FLAG_EXCLUSIVE) 479 open_flags |= O_EXCL; 480#if defined(O_DIRECT) 481 if (flags & IO_FLAG_DIRECT_IO) { 482 open_flags |= O_DIRECT; 483 io->align = ext2fs_get_dio_alignment(data->dev); 484 } 485#elif defined(F_NOCACHE) 486 if (flags & IO_FLAG_DIRECT_IO) { 487 f_nocache = F_NOCACHE; 488 io->align = 4096; 489 } 490#endif 491 data->flags = flags; 492 493 data->dev = ext2fs_open_file(io->name, open_flags, 0); 494 if (data->dev < 0) { 495 retval = errno; 496 goto cleanup; 497 } 498 if (f_nocache) { 499 if (fcntl(data->dev, f_nocache, 1) < 0) { 500 retval = errno; 501 goto cleanup; 502 } 503 } 504 505 /* 506 * If the device is really a block device, then set the 507 * appropriate flag, otherwise we can set DISCARD_ZEROES flag 508 * because we are going to use punch hole instead of discard 509 * and if it succeed, subsequent read from sparse area returns 510 * zero. 511 */ 512 if (ext2fs_stat(io->name, &st) == 0) { 513 if (S_ISBLK(st.st_mode)) 514 io->flags |= CHANNEL_FLAGS_BLOCK_DEVICE; 515 else 516 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES; 517 } 518 519#ifdef BLKDISCARDZEROES 520 ioctl(data->dev, BLKDISCARDZEROES, &zeroes); 521 if (zeroes) 522 io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES; 523#endif 524 525#if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) 526 /* 527 * Some operating systems require that the buffers be aligned, 528 * regardless of O_DIRECT 529 */ 530 if (!io->align) 531 io->align = 512; 532#endif 533 534 535 if ((retval = alloc_cache(io, data))) 536 goto cleanup; 537 538#ifdef BLKROGET 539 if (flags & IO_FLAG_RW) { 540 int error; 541 int readonly = 0; 542 543 /* Is the block device actually writable? */ 544 error = ioctl(data->dev, BLKROGET, &readonly); 545 if (!error && readonly) { 546 close(data->dev); 547 retval = EPERM; 548 goto cleanup; 549 } 550 } 551#endif 552 553#ifdef __linux__ 554#undef RLIM_INFINITY 555#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4))) 556#define RLIM_INFINITY ((unsigned long)(~0UL>>1)) 557#else 558#define RLIM_INFINITY (~0UL) 559#endif 560 /* 561 * Work around a bug in 2.4.10-2.4.18 kernels where writes to 562 * block devices are wrongly getting hit by the filesize 563 * limit. This workaround isn't perfect, since it won't work 564 * if glibc wasn't built against 2.2 header files. (Sigh.) 565 * 566 */ 567 if ((flags & IO_FLAG_RW) && 568 (uname(&ut) == 0) && 569 ((ut.release[0] == '2') && (ut.release[1] == '.') && 570 (ut.release[2] == '4') && (ut.release[3] == '.') && 571 (ut.release[4] == '1') && (ut.release[5] >= '0') && 572 (ut.release[5] < '8')) && 573 (ext2fs_stat(io->name, &st) == 0) && 574 (S_ISBLK(st.st_mode))) { 575 struct rlimit rlim; 576 577 rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY; 578 setrlimit(RLIMIT_FSIZE, &rlim); 579 getrlimit(RLIMIT_FSIZE, &rlim); 580 if (((unsigned long) rlim.rlim_cur) < 581 ((unsigned long) rlim.rlim_max)) { 582 rlim.rlim_cur = rlim.rlim_max; 583 setrlimit(RLIMIT_FSIZE, &rlim); 584 } 585 } 586#endif 587 *channel = io; 588 return 0; 589 590cleanup: 591 if (data) { 592 free_cache(data); 593 ext2fs_free_mem(&data); 594 } 595 if (io) 596 ext2fs_free_mem(&io); 597 return retval; 598} 599 600static errcode_t unix_close(io_channel channel) 601{ 602 struct unix_private_data *data; 603 errcode_t retval = 0; 604 605 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 606 data = (struct unix_private_data *) channel->private_data; 607 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 608 609 if (--channel->refcount > 0) 610 return 0; 611 612#ifndef NO_IO_CACHE 613 retval = flush_cached_blocks(channel, data, 0); 614#endif 615 616 if (close(data->dev) < 0) 617 retval = errno; 618 free_cache(data); 619 620 ext2fs_free_mem(&channel->private_data); 621 if (channel->name) 622 ext2fs_free_mem(&channel->name); 623 ext2fs_free_mem(&channel); 624 return retval; 625} 626 627static errcode_t unix_set_blksize(io_channel channel, int blksize) 628{ 629 struct unix_private_data *data; 630 errcode_t retval; 631 632 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 633 data = (struct unix_private_data *) channel->private_data; 634 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 635 636 if (channel->block_size != blksize) { 637#ifndef NO_IO_CACHE 638 if ((retval = flush_cached_blocks(channel, data, 0))) 639 return retval; 640#endif 641 642 channel->block_size = blksize; 643 free_cache(data); 644 if ((retval = alloc_cache(channel, data))) 645 return retval; 646 } 647 return 0; 648} 649 650 651static errcode_t unix_read_blk64(io_channel channel, unsigned long long block, 652 int count, void *buf) 653{ 654 struct unix_private_data *data; 655 struct unix_cache *cache, *reuse[READ_DIRECT_SIZE]; 656 errcode_t retval; 657 char *cp; 658 int i, j; 659 660 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 661 data = (struct unix_private_data *) channel->private_data; 662 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 663 664#ifdef NO_IO_CACHE 665 return raw_read_blk(channel, data, block, count, buf); 666#else 667 /* 668 * If we're doing an odd-sized read or a very large read, 669 * flush out the cache and then do a direct read. 670 */ 671 if (count < 0 || count > WRITE_DIRECT_SIZE) { 672 if ((retval = flush_cached_blocks(channel, data, 0))) 673 return retval; 674 return raw_read_blk(channel, data, block, count, buf); 675 } 676 677 cp = buf; 678 while (count > 0) { 679 /* If it's in the cache, use it! */ 680 if ((cache = find_cached_block(data, block, &reuse[0]))) { 681#ifdef DEBUG 682 printf("Using cached block %lu\n", block); 683#endif 684 memcpy(cp, cache->buf, channel->block_size); 685 count--; 686 block++; 687 cp += channel->block_size; 688 continue; 689 } 690 if (count == 1) { 691 /* 692 * Special case where we read directly into the 693 * cache buffer; important in the O_DIRECT case 694 */ 695 cache = reuse[0]; 696 reuse_cache(channel, data, cache, block); 697 if ((retval = raw_read_blk(channel, data, block, 1, 698 cache->buf))) { 699 cache->in_use = 0; 700 return retval; 701 } 702 memcpy(cp, cache->buf, channel->block_size); 703 return 0; 704 } 705 706 /* 707 * Find the number of uncached blocks so we can do a 708 * single read request 709 */ 710 for (i=1; i < count; i++) 711 if (find_cached_block(data, block+i, &reuse[i])) 712 break; 713#ifdef DEBUG 714 printf("Reading %d blocks starting at %lu\n", i, block); 715#endif 716 if ((retval = raw_read_blk(channel, data, block, i, cp))) 717 return retval; 718 719 /* Save the results in the cache */ 720 for (j=0; j < i; j++) { 721 count--; 722 cache = reuse[j]; 723 reuse_cache(channel, data, cache, block++); 724 memcpy(cache->buf, cp, channel->block_size); 725 cp += channel->block_size; 726 } 727 } 728 return 0; 729#endif /* NO_IO_CACHE */ 730} 731 732static errcode_t unix_read_blk(io_channel channel, unsigned long block, 733 int count, void *buf) 734{ 735 return unix_read_blk64(channel, block, count, buf); 736} 737 738static errcode_t unix_write_blk64(io_channel channel, unsigned long long block, 739 int count, const void *buf) 740{ 741 struct unix_private_data *data; 742 struct unix_cache *cache, *reuse; 743 errcode_t retval = 0; 744 const char *cp; 745 int writethrough; 746 747 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 748 data = (struct unix_private_data *) channel->private_data; 749 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 750 751#ifdef NO_IO_CACHE 752 return raw_write_blk(channel, data, block, count, buf); 753#else 754 /* 755 * If we're doing an odd-sized write or a very large write, 756 * flush out the cache completely and then do a direct write. 757 */ 758 if (count < 0 || count > WRITE_DIRECT_SIZE) { 759 if ((retval = flush_cached_blocks(channel, data, 1))) 760 return retval; 761 return raw_write_blk(channel, data, block, count, buf); 762 } 763 764 /* 765 * For a moderate-sized multi-block write, first force a write 766 * if we're in write-through cache mode, and then fill the 767 * cache with the blocks. 768 */ 769 writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH; 770 if (writethrough) 771 retval = raw_write_blk(channel, data, block, count, buf); 772 773 cp = buf; 774 while (count > 0) { 775 cache = find_cached_block(data, block, &reuse); 776 if (!cache) { 777 cache = reuse; 778 reuse_cache(channel, data, cache, block); 779 } 780 memcpy(cache->buf, cp, channel->block_size); 781 cache->dirty = !writethrough; 782 count--; 783 block++; 784 cp += channel->block_size; 785 } 786 return retval; 787#endif /* NO_IO_CACHE */ 788} 789 790static errcode_t unix_write_blk(io_channel channel, unsigned long block, 791 int count, const void *buf) 792{ 793 return unix_write_blk64(channel, block, count, buf); 794} 795 796static errcode_t unix_write_byte(io_channel channel, unsigned long offset, 797 int size, const void *buf) 798{ 799 struct unix_private_data *data; 800 errcode_t retval = 0; 801 ssize_t actual; 802 803 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 804 data = (struct unix_private_data *) channel->private_data; 805 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 806 807 if (channel->align != 0) { 808#ifdef ALIGN_DEBUG 809 printf("unix_write_byte: O_DIRECT fallback\n"); 810#endif 811 return EXT2_ET_UNIMPLEMENTED; 812 } 813 814#ifndef NO_IO_CACHE 815 /* 816 * Flush out the cache completely 817 */ 818 if ((retval = flush_cached_blocks(channel, data, 1))) 819 return retval; 820#endif 821 822 if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0) 823 return errno; 824 825 actual = write(data->dev, buf, size); 826 if (actual != size) 827 return EXT2_ET_SHORT_WRITE; 828 829 return 0; 830} 831 832/* 833 * Flush data buffers to disk. 834 */ 835static errcode_t unix_flush(io_channel channel) 836{ 837 struct unix_private_data *data; 838 errcode_t retval = 0; 839 840 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 841 data = (struct unix_private_data *) channel->private_data; 842 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 843 844#ifndef NO_IO_CACHE 845 retval = flush_cached_blocks(channel, data, 0); 846#endif 847 fsync(data->dev); 848 return retval; 849} 850 851static errcode_t unix_set_option(io_channel channel, const char *option, 852 const char *arg) 853{ 854 struct unix_private_data *data; 855 unsigned long long tmp; 856 char *end; 857 858 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 859 data = (struct unix_private_data *) channel->private_data; 860 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 861 862 if (!strcmp(option, "offset")) { 863 if (!arg) 864 return EXT2_ET_INVALID_ARGUMENT; 865 866 tmp = strtoull(arg, &end, 0); 867 if (*end) 868 return EXT2_ET_INVALID_ARGUMENT; 869 data->offset = tmp; 870 if (data->offset < 0) 871 return EXT2_ET_INVALID_ARGUMENT; 872 return 0; 873 } 874 return EXT2_ET_INVALID_ARGUMENT; 875} 876 877#if defined(__linux__) && !defined(BLKDISCARD) 878#define BLKDISCARD _IO(0x12,119) 879#endif 880 881static errcode_t unix_discard(io_channel channel, unsigned long long block, 882 unsigned long long count) 883{ 884 struct unix_private_data *data; 885 __uint64_t range[2]; 886 int ret; 887 888 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); 889 data = (struct unix_private_data *) channel->private_data; 890 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); 891 892 if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) { 893#ifdef BLKDISCARD 894 range[0] = (__uint64_t)(block) * channel->block_size; 895 range[1] = (__uint64_t)(count) * channel->block_size; 896 897 ret = ioctl(data->dev, BLKDISCARD, &range); 898#else 899 goto unimplemented; 900#endif 901 } else { 902#if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE) 903 /* 904 * If we are not on block device, try to use punch hole 905 * to reclaim free space. 906 */ 907 ret = fallocate(data->dev, 908 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 909 (off_t)(block) * channel->block_size, 910 (off_t)(count) * channel->block_size); 911#else 912 goto unimplemented; 913#endif 914 } 915 if (ret < 0) { 916 if (errno == EOPNOTSUPP) 917 goto unimplemented; 918 return errno; 919 } 920 return 0; 921unimplemented: 922 return EXT2_ET_UNIMPLEMENTED; 923} 924