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/blk-integrity.h> 11 #include <linux/buffer_head.h> 12 #include <linux/mpage.h> 13 #include <linux/uio.h> 14 #include <linux/namei.h> 15 #include <linux/task_io_accounting_ops.h> 16 #include <linux/falloc.h> 17 #include <linux/suspend.h> 18 #include <linux/fs.h> 19 #include <linux/iomap.h> 20 #include <linux/module.h> 21 #include <linux/io_uring/cmd.h> 22 #include "blk.h" 23 24 static inline struct inode *bdev_file_inode(struct file *file) 25 { 26 return file->f_mapping->host; 27 } 28 29 static blk_opf_t dio_bio_write_op(struct kiocb *iocb) 30 { 31 blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; 32 33 /* avoid the need for a I/O completion work item */ 34 if (iocb_is_dsync(iocb)) 35 opf |= REQ_FUA; 36 return opf; 37 } 38 39 static bool blkdev_dio_invalid(struct block_device *bdev, struct kiocb *iocb, 40 struct iov_iter *iter) 41 { 42 return (iocb->ki_pos | iov_iter_count(iter)) & 43 (bdev_logical_block_size(bdev) - 1); 44 } 45 46 static inline int blkdev_iov_iter_get_pages(struct bio *bio, 47 struct iov_iter *iter, struct block_device *bdev) 48 { 49 return bio_iov_iter_get_pages(bio, iter, 50 bdev_logical_block_size(bdev) - 1); 51 } 52 53 #define DIO_INLINE_BIO_VECS 4 54 55 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, 56 struct iov_iter *iter, struct block_device *bdev, 57 unsigned int nr_pages) 58 { 59 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; 60 loff_t pos = iocb->ki_pos; 61 bool should_dirty = false; 62 struct bio bio; 63 ssize_t ret; 64 65 if (nr_pages <= DIO_INLINE_BIO_VECS) 66 vecs = inline_vecs; 67 else { 68 vecs = kmalloc_objs(struct bio_vec, nr_pages); 69 if (!vecs) 70 return -ENOMEM; 71 } 72 73 if (iov_iter_rw(iter) == READ) { 74 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ); 75 if (user_backed_iter(iter)) 76 should_dirty = true; 77 } else { 78 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb)); 79 } 80 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 81 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 82 bio.bi_write_stream = iocb->ki_write_stream; 83 bio.bi_ioprio = iocb->ki_ioprio; 84 if (iocb->ki_flags & IOCB_ATOMIC) 85 bio.bi_opf |= REQ_ATOMIC; 86 87 ret = blkdev_iov_iter_get_pages(&bio, iter, bdev); 88 if (unlikely(ret)) 89 goto out; 90 ret = bio.bi_iter.bi_size; 91 92 if (iov_iter_rw(iter) == WRITE) 93 task_io_account_write(ret); 94 95 if (iocb->ki_flags & IOCB_NOWAIT) 96 bio.bi_opf |= REQ_NOWAIT; 97 98 submit_bio_wait(&bio); 99 100 bio_release_pages(&bio, should_dirty); 101 if (unlikely(bio.bi_status)) 102 ret = blk_status_to_errno(bio.bi_status); 103 104 out: 105 if (vecs != inline_vecs) 106 kfree(vecs); 107 108 bio_uninit(&bio); 109 110 return ret; 111 } 112 113 enum { 114 DIO_SHOULD_DIRTY = 1, 115 DIO_IS_SYNC = 2, 116 }; 117 118 struct blkdev_dio { 119 union { 120 struct kiocb *iocb; 121 struct task_struct *waiter; 122 }; 123 size_t size; 124 atomic_t ref; 125 unsigned int flags; 126 struct bio bio ____cacheline_aligned_in_smp; 127 }; 128 129 static struct bio_set blkdev_dio_pool; 130 131 static void blkdev_bio_end_io(struct bio *bio) 132 { 133 struct blkdev_dio *dio = bio->bi_private; 134 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 135 bool is_sync = dio->flags & DIO_IS_SYNC; 136 137 if (bio->bi_status && !dio->bio.bi_status) 138 dio->bio.bi_status = bio->bi_status; 139 140 if (bio_integrity(bio)) 141 bio_integrity_unmap_user(bio); 142 143 if (atomic_dec_and_test(&dio->ref)) { 144 if (!is_sync) { 145 struct kiocb *iocb = dio->iocb; 146 ssize_t ret; 147 148 WRITE_ONCE(iocb->private, NULL); 149 150 if (likely(!dio->bio.bi_status)) { 151 ret = dio->size; 152 iocb->ki_pos += ret; 153 } else { 154 ret = blk_status_to_errno(dio->bio.bi_status); 155 } 156 157 dio->iocb->ki_complete(iocb, ret); 158 bio_put(&dio->bio); 159 } else { 160 struct task_struct *waiter = dio->waiter; 161 162 WRITE_ONCE(dio->waiter, NULL); 163 blk_wake_io_task(waiter); 164 } 165 } 166 167 if (should_dirty) { 168 bio_check_pages_dirty(bio); 169 } else { 170 bio_release_pages(bio, false); 171 bio_put(bio); 172 } 173 } 174 175 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 176 struct block_device *bdev, unsigned int nr_pages) 177 { 178 struct blk_plug plug; 179 struct blkdev_dio *dio; 180 struct bio *bio; 181 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 182 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 183 loff_t pos = iocb->ki_pos; 184 int ret = 0; 185 186 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 187 &blkdev_dio_pool); 188 dio = container_of(bio, struct blkdev_dio, bio); 189 atomic_set(&dio->ref, 1); 190 /* 191 * Grab an extra reference to ensure the dio structure which is embedded 192 * into the first bio stays around. 193 */ 194 bio_get(bio); 195 196 is_sync = is_sync_kiocb(iocb); 197 if (is_sync) { 198 dio->flags = DIO_IS_SYNC; 199 dio->waiter = current; 200 } else { 201 dio->flags = 0; 202 dio->iocb = iocb; 203 } 204 205 dio->size = 0; 206 if (is_read && user_backed_iter(iter)) 207 dio->flags |= DIO_SHOULD_DIRTY; 208 209 blk_start_plug(&plug); 210 211 for (;;) { 212 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 213 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 214 bio->bi_write_stream = iocb->ki_write_stream; 215 bio->bi_private = dio; 216 bio->bi_end_io = blkdev_bio_end_io; 217 bio->bi_ioprio = iocb->ki_ioprio; 218 219 ret = blkdev_iov_iter_get_pages(bio, iter, bdev); 220 if (unlikely(ret)) { 221 bio_endio_status(bio, BLK_STS_IOERR); 222 break; 223 } 224 if (iocb->ki_flags & IOCB_NOWAIT) { 225 /* 226 * This is nonblocking IO, and we need to allocate 227 * another bio if we have data left to map. As we 228 * cannot guarantee that one of the sub bios will not 229 * fail getting issued FOR NOWAIT and as error results 230 * are coalesced across all of them, be safe and ask for 231 * a retry of this from blocking context. 232 */ 233 if (unlikely(iov_iter_count(iter))) { 234 ret = -EAGAIN; 235 goto fail; 236 } 237 bio->bi_opf |= REQ_NOWAIT; 238 } 239 if (iocb->ki_flags & IOCB_HAS_METADATA) { 240 ret = bio_integrity_map_iter(bio, iocb->private); 241 if (unlikely(ret)) 242 goto fail; 243 } 244 245 if (is_read) { 246 if (dio->flags & DIO_SHOULD_DIRTY) 247 bio_set_pages_dirty(bio); 248 } else { 249 task_io_account_write(bio->bi_iter.bi_size); 250 } 251 dio->size += bio->bi_iter.bi_size; 252 pos += bio->bi_iter.bi_size; 253 254 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 255 if (!nr_pages) { 256 submit_bio(bio); 257 break; 258 } 259 atomic_inc(&dio->ref); 260 submit_bio(bio); 261 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 262 } 263 264 blk_finish_plug(&plug); 265 266 if (!is_sync) 267 return -EIOCBQUEUED; 268 269 for (;;) { 270 set_current_state(TASK_UNINTERRUPTIBLE); 271 if (!READ_ONCE(dio->waiter)) 272 break; 273 blk_io_schedule(); 274 } 275 __set_current_state(TASK_RUNNING); 276 277 if (!ret) 278 ret = blk_status_to_errno(dio->bio.bi_status); 279 if (likely(!ret)) 280 ret = dio->size; 281 282 bio_put(&dio->bio); 283 return ret; 284 fail: 285 bio_release_pages(bio, false); 286 bio_clear_flag(bio, BIO_REFFED); 287 bio_put(bio); 288 blk_finish_plug(&plug); 289 return ret; 290 } 291 292 static void blkdev_bio_end_io_async(struct bio *bio) 293 { 294 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 295 struct kiocb *iocb = dio->iocb; 296 ssize_t ret; 297 298 WRITE_ONCE(iocb->private, NULL); 299 300 if (likely(!bio->bi_status)) { 301 ret = dio->size; 302 iocb->ki_pos += ret; 303 } else { 304 ret = blk_status_to_errno(bio->bi_status); 305 } 306 307 if (bio_integrity(bio)) 308 bio_integrity_unmap_user(bio); 309 310 iocb->ki_complete(iocb, ret); 311 312 if (dio->flags & DIO_SHOULD_DIRTY) { 313 bio_check_pages_dirty(bio); 314 } else { 315 bio_release_pages(bio, false); 316 bio_put(bio); 317 } 318 } 319 320 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 321 struct iov_iter *iter, 322 struct block_device *bdev, 323 unsigned int nr_pages) 324 { 325 bool is_read = iov_iter_rw(iter) == READ; 326 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 327 struct blkdev_dio *dio; 328 struct bio *bio; 329 loff_t pos = iocb->ki_pos; 330 int ret = 0; 331 332 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 333 &blkdev_dio_pool); 334 dio = container_of(bio, struct blkdev_dio, bio); 335 dio->flags = 0; 336 dio->iocb = iocb; 337 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 338 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 339 bio->bi_write_stream = iocb->ki_write_stream; 340 bio->bi_end_io = blkdev_bio_end_io_async; 341 bio->bi_ioprio = iocb->ki_ioprio; 342 343 if (iov_iter_is_bvec(iter)) { 344 /* 345 * Users don't rely on the iterator being in any particular 346 * state for async I/O returning -EIOCBQUEUED, hence we can 347 * avoid expensive iov_iter_advance(). Bypass 348 * bio_iov_iter_get_pages() and set the bvec directly. 349 */ 350 bio_iov_bvec_set(bio, iter); 351 } else { 352 ret = blkdev_iov_iter_get_pages(bio, iter, bdev); 353 if (unlikely(ret)) 354 goto out_bio_put; 355 } 356 dio->size = bio->bi_iter.bi_size; 357 358 if (is_read) { 359 if (user_backed_iter(iter)) { 360 dio->flags |= DIO_SHOULD_DIRTY; 361 bio_set_pages_dirty(bio); 362 } 363 } else { 364 task_io_account_write(bio->bi_iter.bi_size); 365 } 366 367 if (iocb->ki_flags & IOCB_HAS_METADATA) { 368 ret = bio_integrity_map_iter(bio, iocb->private); 369 WRITE_ONCE(iocb->private, NULL); 370 if (unlikely(ret)) 371 goto out_bio_put; 372 } 373 374 if (iocb->ki_flags & IOCB_ATOMIC) 375 bio->bi_opf |= REQ_ATOMIC; 376 377 if (iocb->ki_flags & IOCB_NOWAIT) 378 bio->bi_opf |= REQ_NOWAIT; 379 380 if (iocb->ki_flags & IOCB_HIPRI) { 381 bio->bi_opf |= REQ_POLLED; 382 submit_bio(bio); 383 WRITE_ONCE(iocb->private, bio); 384 } else { 385 submit_bio(bio); 386 } 387 return -EIOCBQUEUED; 388 389 out_bio_put: 390 bio_put(bio); 391 return ret; 392 } 393 394 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 395 { 396 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 397 unsigned int nr_pages; 398 399 if (!iov_iter_count(iter)) 400 return 0; 401 402 if (blkdev_dio_invalid(bdev, iocb, iter)) 403 return -EINVAL; 404 405 if (iov_iter_rw(iter) == WRITE) { 406 u16 max_write_streams = bdev_max_write_streams(bdev); 407 408 if (iocb->ki_write_stream) { 409 if (iocb->ki_write_stream > max_write_streams) 410 return -EINVAL; 411 } else if (max_write_streams) { 412 enum rw_hint write_hint = 413 file_inode(iocb->ki_filp)->i_write_hint; 414 415 /* 416 * Just use the write hint as write stream for block 417 * device writes. This assumes no file system is 418 * mounted that would use the streams differently. 419 */ 420 if (write_hint <= max_write_streams) 421 iocb->ki_write_stream = write_hint; 422 } 423 } 424 425 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 426 if (likely(nr_pages <= BIO_MAX_VECS && 427 !(iocb->ki_flags & IOCB_HAS_METADATA))) { 428 if (is_sync_kiocb(iocb)) 429 return __blkdev_direct_IO_simple(iocb, iter, bdev, 430 nr_pages); 431 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages); 432 } else if (iocb->ki_flags & IOCB_ATOMIC) { 433 return -EINVAL; 434 } 435 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages)); 436 } 437 438 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 439 unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 440 { 441 struct block_device *bdev = I_BDEV(inode); 442 loff_t isize = i_size_read(inode); 443 444 if (offset >= isize) 445 return -EIO; 446 447 iomap->bdev = bdev; 448 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev)); 449 iomap->type = IOMAP_MAPPED; 450 iomap->addr = iomap->offset; 451 iomap->length = isize - iomap->offset; 452 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ 453 return 0; 454 } 455 456 static const struct iomap_ops blkdev_iomap_ops = { 457 .iomap_begin = blkdev_iomap_begin, 458 }; 459 460 #ifdef CONFIG_BUFFER_HEAD 461 static int blkdev_get_block(struct inode *inode, sector_t iblock, 462 struct buffer_head *bh, int create) 463 { 464 bh->b_bdev = I_BDEV(inode); 465 bh->b_blocknr = iblock; 466 set_buffer_mapped(bh); 467 return 0; 468 } 469 470 /* 471 * We cannot call mpage_writepages() as it does not take the buffer lock. 472 * We must use block_write_full_folio() directly which holds the buffer 473 * lock. The buffer lock provides the synchronisation with writeback 474 * that filesystems rely on when they use the blockdev's mapping. 475 */ 476 static int blkdev_writepages(struct address_space *mapping, 477 struct writeback_control *wbc) 478 { 479 struct folio *folio = NULL; 480 struct blk_plug plug; 481 int err; 482 483 blk_start_plug(&plug); 484 while ((folio = writeback_iter(mapping, wbc, folio, &err))) 485 err = block_write_full_folio(folio, wbc, blkdev_get_block); 486 blk_finish_plug(&plug); 487 488 return err; 489 } 490 491 static int blkdev_read_folio(struct file *file, struct folio *folio) 492 { 493 return block_read_full_folio(folio, blkdev_get_block); 494 } 495 496 static void blkdev_readahead(struct readahead_control *rac) 497 { 498 mpage_readahead(rac, blkdev_get_block); 499 } 500 501 const struct address_space_operations def_blk_aops = { 502 .dirty_folio = block_dirty_folio, 503 .invalidate_folio = block_invalidate_folio, 504 .read_folio = blkdev_read_folio, 505 .readahead = blkdev_readahead, 506 .writepages = blkdev_writepages, 507 .migrate_folio = buffer_migrate_folio_norefs, 508 .is_dirty_writeback = buffer_check_dirty_writeback, 509 }; 510 #else /* CONFIG_BUFFER_HEAD */ 511 static int blkdev_read_folio(struct file *file, struct folio *folio) 512 { 513 iomap_bio_read_folio(folio, &blkdev_iomap_ops); 514 return 0; 515 } 516 517 static void blkdev_readahead(struct readahead_control *rac) 518 { 519 iomap_bio_readahead(rac, &blkdev_iomap_ops); 520 } 521 522 static ssize_t blkdev_writeback_range(struct iomap_writepage_ctx *wpc, 523 struct folio *folio, u64 offset, unsigned int len, u64 end_pos) 524 { 525 loff_t isize = i_size_read(wpc->inode); 526 527 if (WARN_ON_ONCE(offset >= isize)) 528 return -EIO; 529 530 if (offset < wpc->iomap.offset || 531 offset >= wpc->iomap.offset + wpc->iomap.length) { 532 int error; 533 534 error = blkdev_iomap_begin(wpc->inode, offset, isize - offset, 535 IOMAP_WRITE, &wpc->iomap, NULL); 536 if (error) 537 return error; 538 } 539 540 return iomap_add_to_ioend(wpc, folio, offset, end_pos, len); 541 } 542 543 static const struct iomap_writeback_ops blkdev_writeback_ops = { 544 .writeback_range = blkdev_writeback_range, 545 .writeback_submit = iomap_ioend_writeback_submit, 546 }; 547 548 static int blkdev_writepages(struct address_space *mapping, 549 struct writeback_control *wbc) 550 { 551 struct iomap_writepage_ctx wpc = { 552 .inode = mapping->host, 553 .wbc = wbc, 554 .ops = &blkdev_writeback_ops 555 }; 556 557 return iomap_writepages(&wpc); 558 } 559 560 const struct address_space_operations def_blk_aops = { 561 .dirty_folio = filemap_dirty_folio, 562 .release_folio = iomap_release_folio, 563 .invalidate_folio = iomap_invalidate_folio, 564 .read_folio = blkdev_read_folio, 565 .readahead = blkdev_readahead, 566 .writepages = blkdev_writepages, 567 .is_partially_uptodate = iomap_is_partially_uptodate, 568 .error_remove_folio = generic_error_remove_folio, 569 .migrate_folio = filemap_migrate_folio, 570 }; 571 #endif /* CONFIG_BUFFER_HEAD */ 572 573 /* 574 * for a block special file file_inode(file)->i_size is zero 575 * so we compute the size by hand (just as in block_read/write above) 576 */ 577 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 578 { 579 struct inode *bd_inode = bdev_file_inode(file); 580 loff_t retval; 581 582 inode_lock(bd_inode); 583 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 584 inode_unlock(bd_inode); 585 return retval; 586 } 587 588 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 589 int datasync) 590 { 591 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 592 int error; 593 594 error = file_write_and_wait_range(filp, start, end); 595 if (error) 596 return error; 597 598 /* 599 * There is no need to serialise calls to blkdev_issue_flush with 600 * i_mutex and doing so causes performance issues with concurrent 601 * O_SYNC writers to a block device. 602 */ 603 error = blkdev_issue_flush(bdev); 604 if (error == -EOPNOTSUPP) 605 error = 0; 606 607 return error; 608 } 609 610 /** 611 * file_to_blk_mode - get block open flags from file flags 612 * @file: file whose open flags should be converted 613 * 614 * Look at file open flags and generate corresponding block open flags from 615 * them. The function works both for file just being open (e.g. during ->open 616 * callback) and for file that is already open. This is actually non-trivial 617 * (see comment in the function). 618 */ 619 blk_mode_t file_to_blk_mode(struct file *file) 620 { 621 blk_mode_t mode = 0; 622 623 if (file->f_mode & FMODE_READ) 624 mode |= BLK_OPEN_READ; 625 if (file->f_mode & FMODE_WRITE) 626 mode |= BLK_OPEN_WRITE; 627 /* 628 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data 629 * to determine whether the open was exclusive for already open files. 630 */ 631 if (file->private_data) 632 mode |= BLK_OPEN_EXCL; 633 else if (file->f_flags & O_EXCL) 634 mode |= BLK_OPEN_EXCL; 635 if (file->f_flags & O_NDELAY) 636 mode |= BLK_OPEN_NDELAY; 637 638 /* 639 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 640 * driver has historically allowed ioctls as if the file was opened for 641 * writing, but does not allow and actual reads or writes. 642 */ 643 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 644 mode |= BLK_OPEN_WRITE_IOCTL; 645 646 return mode; 647 } 648 649 static int blkdev_open(struct inode *inode, struct file *filp) 650 { 651 struct block_device *bdev; 652 blk_mode_t mode; 653 int ret; 654 655 mode = file_to_blk_mode(filp); 656 /* Use the file as the holder. */ 657 if (mode & BLK_OPEN_EXCL) 658 filp->private_data = filp; 659 ret = bdev_permission(inode->i_rdev, mode, filp->private_data); 660 if (ret) 661 return ret; 662 663 bdev = blkdev_get_no_open(inode->i_rdev, true); 664 if (!bdev) 665 return -ENXIO; 666 667 if (bdev_can_atomic_write(bdev)) 668 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE; 669 if (blk_get_integrity(bdev->bd_disk)) 670 filp->f_mode |= FMODE_HAS_METADATA; 671 672 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp); 673 if (ret) 674 blkdev_put_no_open(bdev); 675 return ret; 676 } 677 678 static int blkdev_release(struct inode *inode, struct file *filp) 679 { 680 bdev_release(filp); 681 return 0; 682 } 683 684 static ssize_t 685 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from) 686 { 687 size_t count = iov_iter_count(from); 688 ssize_t written; 689 690 written = kiocb_invalidate_pages(iocb, count); 691 if (written) { 692 if (written == -EBUSY) 693 return 0; 694 return written; 695 } 696 697 written = blkdev_direct_IO(iocb, from); 698 if (written > 0) { 699 kiocb_invalidate_post_direct_write(iocb, count); 700 iocb->ki_pos += written; 701 count -= written; 702 } 703 if (written != -EIOCBQUEUED) 704 iov_iter_revert(from, count - iov_iter_count(from)); 705 return written; 706 } 707 708 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from) 709 { 710 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL, 711 NULL); 712 } 713 714 /* 715 * Write data to the block device. Only intended for the block device itself 716 * and the raw driver which basically is a fake block device. 717 * 718 * Does not take i_mutex for the write and thus is not for general purpose 719 * use. 720 */ 721 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 722 { 723 struct file *file = iocb->ki_filp; 724 struct inode *bd_inode = bdev_file_inode(file); 725 struct block_device *bdev = I_BDEV(bd_inode); 726 bool atomic = iocb->ki_flags & IOCB_ATOMIC; 727 loff_t size = bdev_nr_bytes(bdev); 728 size_t shorted = 0; 729 ssize_t ret; 730 731 if (bdev_read_only(bdev)) 732 return -EPERM; 733 734 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 735 return -ETXTBSY; 736 737 if (!iov_iter_count(from)) 738 return 0; 739 740 if (iocb->ki_pos >= size) 741 return -ENOSPC; 742 743 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 744 return -EOPNOTSUPP; 745 746 if (atomic) { 747 ret = generic_atomic_write_valid(iocb, from); 748 if (ret) 749 return ret; 750 } 751 752 size -= iocb->ki_pos; 753 if (iov_iter_count(from) > size) { 754 if (atomic) 755 return -EINVAL; 756 shorted = iov_iter_count(from) - size; 757 iov_iter_truncate(from, size); 758 } 759 760 ret = file_update_time(file); 761 if (ret) 762 return ret; 763 764 if (iocb->ki_flags & IOCB_DIRECT) { 765 ret = blkdev_direct_write(iocb, from); 766 if (ret >= 0 && iov_iter_count(from)) 767 ret = direct_write_fallback(iocb, from, ret, 768 blkdev_buffered_write(iocb, from)); 769 } else { 770 /* 771 * Take i_rwsem and invalidate_lock to avoid racing with 772 * set_blocksize changing i_blkbits/folio order and punching 773 * out the pagecache. 774 */ 775 inode_lock_shared(bd_inode); 776 ret = blkdev_buffered_write(iocb, from); 777 inode_unlock_shared(bd_inode); 778 } 779 780 if (ret > 0) 781 ret = generic_write_sync(iocb, ret); 782 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 783 return ret; 784 } 785 786 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 787 { 788 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp); 789 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 790 loff_t size = bdev_nr_bytes(bdev); 791 loff_t pos = iocb->ki_pos; 792 size_t shorted = 0; 793 ssize_t ret = 0; 794 size_t count; 795 796 if (unlikely(pos + iov_iter_count(to) > size)) { 797 if (pos >= size) 798 return 0; 799 size -= pos; 800 shorted = iov_iter_count(to) - size; 801 iov_iter_truncate(to, size); 802 } 803 804 count = iov_iter_count(to); 805 if (!count) 806 goto reexpand; /* skip atime */ 807 808 if (iocb->ki_flags & IOCB_DIRECT) { 809 ret = kiocb_write_and_wait(iocb, count); 810 if (ret < 0) 811 goto reexpand; 812 file_accessed(iocb->ki_filp); 813 814 ret = blkdev_direct_IO(iocb, to); 815 if (ret > 0) { 816 iocb->ki_pos += ret; 817 count -= ret; 818 } 819 if (ret != -EIOCBQUEUED) 820 iov_iter_revert(to, count - iov_iter_count(to)); 821 if (ret < 0 || !count) 822 goto reexpand; 823 } 824 825 /* 826 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize 827 * changing i_blkbits/folio order and punching out the pagecache. 828 */ 829 inode_lock_shared(bd_inode); 830 ret = filemap_read(iocb, to, ret); 831 inode_unlock_shared(bd_inode); 832 833 reexpand: 834 if (unlikely(shorted)) 835 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 836 return ret; 837 } 838 839 #define BLKDEV_FALLOC_FL_SUPPORTED \ 840 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 841 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES) 842 843 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 844 loff_t len) 845 { 846 struct inode *inode = bdev_file_inode(file); 847 struct block_device *bdev = I_BDEV(inode); 848 loff_t end = start + len - 1; 849 loff_t isize; 850 unsigned int flags; 851 int error; 852 853 /* Fail if we don't recognize the flags. */ 854 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 855 return -EOPNOTSUPP; 856 /* 857 * Don't allow writing zeroes if the device does not enable the 858 * unmap write zeroes operation. 859 */ 860 if ((mode & FALLOC_FL_WRITE_ZEROES) && 861 !bdev_write_zeroes_unmap_sectors(bdev)) 862 return -EOPNOTSUPP; 863 864 /* Don't go off the end of the device. */ 865 isize = bdev_nr_bytes(bdev); 866 if (start >= isize) 867 return -EINVAL; 868 if (end >= isize) { 869 if (mode & FALLOC_FL_KEEP_SIZE) { 870 len = isize - start; 871 end = start + len - 1; 872 } else 873 return -EINVAL; 874 } 875 876 /* 877 * Don't allow IO that isn't aligned to logical block size. 878 */ 879 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 880 return -EINVAL; 881 882 inode_lock(inode); 883 filemap_invalidate_lock(inode->i_mapping); 884 885 switch (mode) { 886 case FALLOC_FL_ZERO_RANGE: 887 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 888 flags = BLKDEV_ZERO_NOUNMAP; 889 break; 890 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 891 flags = BLKDEV_ZERO_NOFALLBACK; 892 break; 893 case FALLOC_FL_WRITE_ZEROES: 894 flags = 0; 895 break; 896 default: 897 error = -EOPNOTSUPP; 898 goto fail; 899 } 900 901 /* 902 * Invalidate the page cache, including dirty pages, for valid 903 * de-allocate mode calls to fallocate(). 904 */ 905 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 906 if (error) 907 goto fail; 908 909 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 910 len >> SECTOR_SHIFT, GFP_KERNEL, flags); 911 fail: 912 filemap_invalidate_unlock(inode->i_mapping); 913 inode_unlock(inode); 914 return error; 915 } 916 917 static int blkdev_mmap_prepare(struct vm_area_desc *desc) 918 { 919 struct file *file = desc->file; 920 921 if (bdev_read_only(I_BDEV(bdev_file_inode(file)))) 922 return generic_file_readonly_mmap_prepare(desc); 923 924 return generic_file_mmap_prepare(desc); 925 } 926 927 const struct file_operations def_blk_fops = { 928 .open = blkdev_open, 929 .release = blkdev_release, 930 .llseek = blkdev_llseek, 931 .read_iter = blkdev_read_iter, 932 .write_iter = blkdev_write_iter, 933 .iopoll = iocb_bio_iopoll, 934 .mmap_prepare = blkdev_mmap_prepare, 935 .fsync = blkdev_fsync, 936 .unlocked_ioctl = blkdev_ioctl, 937 #ifdef CONFIG_COMPAT 938 .compat_ioctl = compat_blkdev_ioctl, 939 #endif 940 .splice_read = filemap_splice_read, 941 .splice_write = iter_file_splice_write, 942 .fallocate = blkdev_fallocate, 943 .uring_cmd = blkdev_uring_cmd, 944 .fop_flags = FOP_BUFFER_RASYNC, 945 }; 946 947 static __init int blkdev_init(void) 948 { 949 return bioset_init(&blkdev_dio_pool, 4, 950 offsetof(struct blkdev_dio, bio), 951 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 952 } 953 module_init(blkdev_init); 954