1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE 5 * Copyright (C) 2016 - 2020 Christoph Hellwig 6 */ 7 #include <linux/init.h> 8 #include <linux/mm.h> 9 #include <linux/blkdev.h> 10 #include <linux/buffer_head.h> 11 #include <linux/mpage.h> 12 #include <linux/uio.h> 13 #include <linux/namei.h> 14 #include <linux/task_io_accounting_ops.h> 15 #include <linux/falloc.h> 16 #include <linux/suspend.h> 17 #include <linux/fs.h> 18 #include <linux/module.h> 19 #include "blk.h" 20 21 static inline struct inode *bdev_file_inode(struct file *file) 22 { 23 return file->f_mapping->host; 24 } 25 26 static int blkdev_get_block(struct inode *inode, sector_t iblock, 27 struct buffer_head *bh, int create) 28 { 29 bh->b_bdev = I_BDEV(inode); 30 bh->b_blocknr = iblock; 31 set_buffer_mapped(bh); 32 return 0; 33 } 34 35 static unsigned int dio_bio_write_op(struct kiocb *iocb) 36 { 37 unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; 38 39 /* avoid the need for a I/O completion work item */ 40 if (iocb->ki_flags & IOCB_DSYNC) 41 op |= REQ_FUA; 42 return op; 43 } 44 45 #define DIO_INLINE_BIO_VECS 4 46 47 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, 48 struct iov_iter *iter, unsigned int nr_pages) 49 { 50 struct block_device *bdev = iocb->ki_filp->private_data; 51 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; 52 loff_t pos = iocb->ki_pos; 53 bool should_dirty = false; 54 struct bio bio; 55 ssize_t ret; 56 57 if ((pos | iov_iter_alignment(iter)) & 58 (bdev_logical_block_size(bdev) - 1)) 59 return -EINVAL; 60 61 if (nr_pages <= DIO_INLINE_BIO_VECS) 62 vecs = inline_vecs; 63 else { 64 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec), 65 GFP_KERNEL); 66 if (!vecs) 67 return -ENOMEM; 68 } 69 70 if (iov_iter_rw(iter) == READ) { 71 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ); 72 if (iter_is_iovec(iter)) 73 should_dirty = true; 74 } else { 75 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb)); 76 } 77 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 78 bio.bi_ioprio = iocb->ki_ioprio; 79 80 ret = bio_iov_iter_get_pages(&bio, iter); 81 if (unlikely(ret)) 82 goto out; 83 ret = bio.bi_iter.bi_size; 84 85 if (iov_iter_rw(iter) == WRITE) 86 task_io_account_write(ret); 87 88 if (iocb->ki_flags & IOCB_NOWAIT) 89 bio.bi_opf |= REQ_NOWAIT; 90 91 submit_bio_wait(&bio); 92 93 bio_release_pages(&bio, should_dirty); 94 if (unlikely(bio.bi_status)) 95 ret = blk_status_to_errno(bio.bi_status); 96 97 out: 98 if (vecs != inline_vecs) 99 kfree(vecs); 100 101 bio_uninit(&bio); 102 103 return ret; 104 } 105 106 enum { 107 DIO_SHOULD_DIRTY = 1, 108 DIO_IS_SYNC = 2, 109 }; 110 111 struct blkdev_dio { 112 union { 113 struct kiocb *iocb; 114 struct task_struct *waiter; 115 }; 116 size_t size; 117 atomic_t ref; 118 unsigned int flags; 119 struct bio bio ____cacheline_aligned_in_smp; 120 }; 121 122 static struct bio_set blkdev_dio_pool; 123 124 static void blkdev_bio_end_io(struct bio *bio) 125 { 126 struct blkdev_dio *dio = bio->bi_private; 127 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 128 129 if (bio->bi_status && !dio->bio.bi_status) 130 dio->bio.bi_status = bio->bi_status; 131 132 if (atomic_dec_and_test(&dio->ref)) { 133 if (!(dio->flags & DIO_IS_SYNC)) { 134 struct kiocb *iocb = dio->iocb; 135 ssize_t ret; 136 137 WRITE_ONCE(iocb->private, NULL); 138 139 if (likely(!dio->bio.bi_status)) { 140 ret = dio->size; 141 iocb->ki_pos += ret; 142 } else { 143 ret = blk_status_to_errno(dio->bio.bi_status); 144 } 145 146 dio->iocb->ki_complete(iocb, ret); 147 bio_put(&dio->bio); 148 } else { 149 struct task_struct *waiter = dio->waiter; 150 151 WRITE_ONCE(dio->waiter, NULL); 152 blk_wake_io_task(waiter); 153 } 154 } 155 156 if (should_dirty) { 157 bio_check_pages_dirty(bio); 158 } else { 159 bio_release_pages(bio, false); 160 bio_put(bio); 161 } 162 } 163 164 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 165 unsigned int nr_pages) 166 { 167 struct block_device *bdev = iocb->ki_filp->private_data; 168 struct blk_plug plug; 169 struct blkdev_dio *dio; 170 struct bio *bio; 171 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 172 unsigned int opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 173 loff_t pos = iocb->ki_pos; 174 int ret = 0; 175 176 if ((pos | iov_iter_alignment(iter)) & 177 (bdev_logical_block_size(bdev) - 1)) 178 return -EINVAL; 179 180 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 181 opf |= REQ_ALLOC_CACHE; 182 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 183 &blkdev_dio_pool); 184 dio = container_of(bio, struct blkdev_dio, bio); 185 atomic_set(&dio->ref, 1); 186 /* 187 * Grab an extra reference to ensure the dio structure which is embedded 188 * into the first bio stays around. 189 */ 190 bio_get(bio); 191 192 is_sync = is_sync_kiocb(iocb); 193 if (is_sync) { 194 dio->flags = DIO_IS_SYNC; 195 dio->waiter = current; 196 } else { 197 dio->flags = 0; 198 dio->iocb = iocb; 199 } 200 201 dio->size = 0; 202 if (is_read && iter_is_iovec(iter)) 203 dio->flags |= DIO_SHOULD_DIRTY; 204 205 blk_start_plug(&plug); 206 207 for (;;) { 208 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 209 bio->bi_private = dio; 210 bio->bi_end_io = blkdev_bio_end_io; 211 bio->bi_ioprio = iocb->ki_ioprio; 212 213 ret = bio_iov_iter_get_pages(bio, iter); 214 if (unlikely(ret)) { 215 bio->bi_status = BLK_STS_IOERR; 216 bio_endio(bio); 217 break; 218 } 219 220 if (is_read) { 221 if (dio->flags & DIO_SHOULD_DIRTY) 222 bio_set_pages_dirty(bio); 223 } else { 224 task_io_account_write(bio->bi_iter.bi_size); 225 } 226 if (iocb->ki_flags & IOCB_NOWAIT) 227 bio->bi_opf |= REQ_NOWAIT; 228 229 dio->size += bio->bi_iter.bi_size; 230 pos += bio->bi_iter.bi_size; 231 232 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 233 if (!nr_pages) { 234 submit_bio(bio); 235 break; 236 } 237 atomic_inc(&dio->ref); 238 submit_bio(bio); 239 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 240 } 241 242 blk_finish_plug(&plug); 243 244 if (!is_sync) 245 return -EIOCBQUEUED; 246 247 for (;;) { 248 set_current_state(TASK_UNINTERRUPTIBLE); 249 if (!READ_ONCE(dio->waiter)) 250 break; 251 blk_io_schedule(); 252 } 253 __set_current_state(TASK_RUNNING); 254 255 if (!ret) 256 ret = blk_status_to_errno(dio->bio.bi_status); 257 if (likely(!ret)) 258 ret = dio->size; 259 260 bio_put(&dio->bio); 261 return ret; 262 } 263 264 static void blkdev_bio_end_io_async(struct bio *bio) 265 { 266 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 267 struct kiocb *iocb = dio->iocb; 268 ssize_t ret; 269 270 WRITE_ONCE(iocb->private, NULL); 271 272 if (likely(!bio->bi_status)) { 273 ret = dio->size; 274 iocb->ki_pos += ret; 275 } else { 276 ret = blk_status_to_errno(bio->bi_status); 277 } 278 279 iocb->ki_complete(iocb, ret); 280 281 if (dio->flags & DIO_SHOULD_DIRTY) { 282 bio_check_pages_dirty(bio); 283 } else { 284 bio_release_pages(bio, false); 285 bio_put(bio); 286 } 287 } 288 289 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 290 struct iov_iter *iter, 291 unsigned int nr_pages) 292 { 293 struct block_device *bdev = iocb->ki_filp->private_data; 294 bool is_read = iov_iter_rw(iter) == READ; 295 unsigned int opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 296 struct blkdev_dio *dio; 297 struct bio *bio; 298 loff_t pos = iocb->ki_pos; 299 int ret = 0; 300 301 if ((pos | iov_iter_alignment(iter)) & 302 (bdev_logical_block_size(bdev) - 1)) 303 return -EINVAL; 304 305 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 306 opf |= REQ_ALLOC_CACHE; 307 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 308 &blkdev_dio_pool); 309 dio = container_of(bio, struct blkdev_dio, bio); 310 dio->flags = 0; 311 dio->iocb = iocb; 312 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 313 bio->bi_end_io = blkdev_bio_end_io_async; 314 bio->bi_ioprio = iocb->ki_ioprio; 315 316 if (iov_iter_is_bvec(iter)) { 317 /* 318 * Users don't rely on the iterator being in any particular 319 * state for async I/O returning -EIOCBQUEUED, hence we can 320 * avoid expensive iov_iter_advance(). Bypass 321 * bio_iov_iter_get_pages() and set the bvec directly. 322 */ 323 bio_iov_bvec_set(bio, iter); 324 } else { 325 ret = bio_iov_iter_get_pages(bio, iter); 326 if (unlikely(ret)) { 327 bio_put(bio); 328 return ret; 329 } 330 } 331 dio->size = bio->bi_iter.bi_size; 332 333 if (is_read) { 334 if (iter_is_iovec(iter)) { 335 dio->flags |= DIO_SHOULD_DIRTY; 336 bio_set_pages_dirty(bio); 337 } 338 } else { 339 task_io_account_write(bio->bi_iter.bi_size); 340 } 341 342 if (iocb->ki_flags & IOCB_HIPRI) { 343 bio->bi_opf |= REQ_POLLED | REQ_NOWAIT; 344 submit_bio(bio); 345 WRITE_ONCE(iocb->private, bio); 346 } else { 347 if (iocb->ki_flags & IOCB_NOWAIT) 348 bio->bi_opf |= REQ_NOWAIT; 349 submit_bio(bio); 350 } 351 return -EIOCBQUEUED; 352 } 353 354 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 355 { 356 unsigned int nr_pages; 357 358 if (!iov_iter_count(iter)) 359 return 0; 360 361 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 362 if (likely(nr_pages <= BIO_MAX_VECS)) { 363 if (is_sync_kiocb(iocb)) 364 return __blkdev_direct_IO_simple(iocb, iter, nr_pages); 365 return __blkdev_direct_IO_async(iocb, iter, nr_pages); 366 } 367 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages)); 368 } 369 370 static int blkdev_writepage(struct page *page, struct writeback_control *wbc) 371 { 372 return block_write_full_page(page, blkdev_get_block, wbc); 373 } 374 375 static int blkdev_read_folio(struct file *file, struct folio *folio) 376 { 377 return block_read_full_folio(folio, blkdev_get_block); 378 } 379 380 static void blkdev_readahead(struct readahead_control *rac) 381 { 382 mpage_readahead(rac, blkdev_get_block); 383 } 384 385 static int blkdev_write_begin(struct file *file, struct address_space *mapping, 386 loff_t pos, unsigned len, struct page **pagep, void **fsdata) 387 { 388 return block_write_begin(mapping, pos, len, pagep, blkdev_get_block); 389 } 390 391 static int blkdev_write_end(struct file *file, struct address_space *mapping, 392 loff_t pos, unsigned len, unsigned copied, struct page *page, 393 void *fsdata) 394 { 395 int ret; 396 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); 397 398 unlock_page(page); 399 put_page(page); 400 401 return ret; 402 } 403 404 static int blkdev_writepages(struct address_space *mapping, 405 struct writeback_control *wbc) 406 { 407 return generic_writepages(mapping, wbc); 408 } 409 410 const struct address_space_operations def_blk_aops = { 411 .dirty_folio = block_dirty_folio, 412 .invalidate_folio = block_invalidate_folio, 413 .read_folio = blkdev_read_folio, 414 .readahead = blkdev_readahead, 415 .writepage = blkdev_writepage, 416 .write_begin = blkdev_write_begin, 417 .write_end = blkdev_write_end, 418 .writepages = blkdev_writepages, 419 .direct_IO = blkdev_direct_IO, 420 .migratepage = buffer_migrate_page_norefs, 421 .is_dirty_writeback = buffer_check_dirty_writeback, 422 }; 423 424 /* 425 * for a block special file file_inode(file)->i_size is zero 426 * so we compute the size by hand (just as in block_read/write above) 427 */ 428 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 429 { 430 struct inode *bd_inode = bdev_file_inode(file); 431 loff_t retval; 432 433 inode_lock(bd_inode); 434 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 435 inode_unlock(bd_inode); 436 return retval; 437 } 438 439 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 440 int datasync) 441 { 442 struct block_device *bdev = filp->private_data; 443 int error; 444 445 error = file_write_and_wait_range(filp, start, end); 446 if (error) 447 return error; 448 449 /* 450 * There is no need to serialise calls to blkdev_issue_flush with 451 * i_mutex and doing so causes performance issues with concurrent 452 * O_SYNC writers to a block device. 453 */ 454 error = blkdev_issue_flush(bdev); 455 if (error == -EOPNOTSUPP) 456 error = 0; 457 458 return error; 459 } 460 461 static int blkdev_open(struct inode *inode, struct file *filp) 462 { 463 struct block_device *bdev; 464 465 /* 466 * Preserve backwards compatibility and allow large file access 467 * even if userspace doesn't ask for it explicitly. Some mkfs 468 * binary needs it. We might want to drop this workaround 469 * during an unstable branch. 470 */ 471 filp->f_flags |= O_LARGEFILE; 472 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC; 473 474 if (filp->f_flags & O_NDELAY) 475 filp->f_mode |= FMODE_NDELAY; 476 if (filp->f_flags & O_EXCL) 477 filp->f_mode |= FMODE_EXCL; 478 if ((filp->f_flags & O_ACCMODE) == 3) 479 filp->f_mode |= FMODE_WRITE_IOCTL; 480 481 bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp); 482 if (IS_ERR(bdev)) 483 return PTR_ERR(bdev); 484 485 filp->private_data = bdev; 486 filp->f_mapping = bdev->bd_inode->i_mapping; 487 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); 488 return 0; 489 } 490 491 static int blkdev_close(struct inode *inode, struct file *filp) 492 { 493 struct block_device *bdev = filp->private_data; 494 495 blkdev_put(bdev, filp->f_mode); 496 return 0; 497 } 498 499 /* 500 * Write data to the block device. Only intended for the block device itself 501 * and the raw driver which basically is a fake block device. 502 * 503 * Does not take i_mutex for the write and thus is not for general purpose 504 * use. 505 */ 506 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 507 { 508 struct block_device *bdev = iocb->ki_filp->private_data; 509 struct inode *bd_inode = bdev->bd_inode; 510 loff_t size = bdev_nr_bytes(bdev); 511 struct blk_plug plug; 512 size_t shorted = 0; 513 ssize_t ret; 514 515 if (bdev_read_only(bdev)) 516 return -EPERM; 517 518 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 519 return -ETXTBSY; 520 521 if (!iov_iter_count(from)) 522 return 0; 523 524 if (iocb->ki_pos >= size) 525 return -ENOSPC; 526 527 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 528 return -EOPNOTSUPP; 529 530 size -= iocb->ki_pos; 531 if (iov_iter_count(from) > size) { 532 shorted = iov_iter_count(from) - size; 533 iov_iter_truncate(from, size); 534 } 535 536 blk_start_plug(&plug); 537 ret = __generic_file_write_iter(iocb, from); 538 if (ret > 0) 539 ret = generic_write_sync(iocb, ret); 540 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 541 blk_finish_plug(&plug); 542 return ret; 543 } 544 545 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 546 { 547 struct block_device *bdev = iocb->ki_filp->private_data; 548 loff_t size = bdev_nr_bytes(bdev); 549 loff_t pos = iocb->ki_pos; 550 size_t shorted = 0; 551 ssize_t ret = 0; 552 size_t count; 553 554 if (unlikely(pos + iov_iter_count(to) > size)) { 555 if (pos >= size) 556 return 0; 557 size -= pos; 558 shorted = iov_iter_count(to) - size; 559 iov_iter_truncate(to, size); 560 } 561 562 count = iov_iter_count(to); 563 if (!count) 564 goto reexpand; /* skip atime */ 565 566 if (iocb->ki_flags & IOCB_DIRECT) { 567 struct address_space *mapping = iocb->ki_filp->f_mapping; 568 569 if (iocb->ki_flags & IOCB_NOWAIT) { 570 if (filemap_range_needs_writeback(mapping, pos, 571 pos + count - 1)) { 572 ret = -EAGAIN; 573 goto reexpand; 574 } 575 } else { 576 ret = filemap_write_and_wait_range(mapping, pos, 577 pos + count - 1); 578 if (ret < 0) 579 goto reexpand; 580 } 581 582 file_accessed(iocb->ki_filp); 583 584 ret = blkdev_direct_IO(iocb, to); 585 if (ret >= 0) { 586 iocb->ki_pos += ret; 587 count -= ret; 588 } 589 iov_iter_revert(to, count - iov_iter_count(to)); 590 if (ret < 0 || !count) 591 goto reexpand; 592 } 593 594 ret = filemap_read(iocb, to, ret); 595 596 reexpand: 597 if (unlikely(shorted)) 598 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 599 return ret; 600 } 601 602 #define BLKDEV_FALLOC_FL_SUPPORTED \ 603 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 604 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) 605 606 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 607 loff_t len) 608 { 609 struct inode *inode = bdev_file_inode(file); 610 struct block_device *bdev = I_BDEV(inode); 611 loff_t end = start + len - 1; 612 loff_t isize; 613 int error; 614 615 /* Fail if we don't recognize the flags. */ 616 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 617 return -EOPNOTSUPP; 618 619 /* Don't go off the end of the device. */ 620 isize = bdev_nr_bytes(bdev); 621 if (start >= isize) 622 return -EINVAL; 623 if (end >= isize) { 624 if (mode & FALLOC_FL_KEEP_SIZE) { 625 len = isize - start; 626 end = start + len - 1; 627 } else 628 return -EINVAL; 629 } 630 631 /* 632 * Don't allow IO that isn't aligned to logical block size. 633 */ 634 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 635 return -EINVAL; 636 637 filemap_invalidate_lock(inode->i_mapping); 638 639 /* Invalidate the page cache, including dirty pages. */ 640 error = truncate_bdev_range(bdev, file->f_mode, start, end); 641 if (error) 642 goto fail; 643 644 switch (mode) { 645 case FALLOC_FL_ZERO_RANGE: 646 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 647 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 648 len >> SECTOR_SHIFT, GFP_KERNEL, 649 BLKDEV_ZERO_NOUNMAP); 650 break; 651 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 652 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 653 len >> SECTOR_SHIFT, GFP_KERNEL, 654 BLKDEV_ZERO_NOFALLBACK); 655 break; 656 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: 657 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, 658 len >> SECTOR_SHIFT, GFP_KERNEL); 659 break; 660 default: 661 error = -EOPNOTSUPP; 662 } 663 664 fail: 665 filemap_invalidate_unlock(inode->i_mapping); 666 return error; 667 } 668 669 const struct file_operations def_blk_fops = { 670 .open = blkdev_open, 671 .release = blkdev_close, 672 .llseek = blkdev_llseek, 673 .read_iter = blkdev_read_iter, 674 .write_iter = blkdev_write_iter, 675 .iopoll = iocb_bio_iopoll, 676 .mmap = generic_file_mmap, 677 .fsync = blkdev_fsync, 678 .unlocked_ioctl = blkdev_ioctl, 679 #ifdef CONFIG_COMPAT 680 .compat_ioctl = compat_blkdev_ioctl, 681 #endif 682 .splice_read = generic_file_splice_read, 683 .splice_write = iter_file_splice_write, 684 .fallocate = blkdev_fallocate, 685 }; 686 687 static __init int blkdev_init(void) 688 { 689 return bioset_init(&blkdev_dio_pool, 4, 690 offsetof(struct blkdev_dio, bio), 691 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 692 } 693 module_init(blkdev_init); 694