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 & (bdev_logical_block_size(bdev) - 1) || 43 !bdev_iter_is_aligned(bdev, iter); 44 } 45 46 #define DIO_INLINE_BIO_VECS 4 47 48 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, 49 struct iov_iter *iter, struct block_device *bdev, 50 unsigned int nr_pages) 51 { 52 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; 53 loff_t pos = iocb->ki_pos; 54 bool should_dirty = false; 55 struct bio bio; 56 ssize_t ret; 57 58 if (nr_pages <= DIO_INLINE_BIO_VECS) 59 vecs = inline_vecs; 60 else { 61 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec), 62 GFP_KERNEL); 63 if (!vecs) 64 return -ENOMEM; 65 } 66 67 if (iov_iter_rw(iter) == READ) { 68 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ); 69 if (user_backed_iter(iter)) 70 should_dirty = true; 71 } else { 72 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb)); 73 } 74 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 75 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 76 bio.bi_write_stream = iocb->ki_write_stream; 77 bio.bi_ioprio = iocb->ki_ioprio; 78 if (iocb->ki_flags & IOCB_ATOMIC) 79 bio.bi_opf |= REQ_ATOMIC; 80 81 ret = bio_iov_iter_get_pages(&bio, iter); 82 if (unlikely(ret)) 83 goto out; 84 ret = bio.bi_iter.bi_size; 85 86 if (iov_iter_rw(iter) == WRITE) 87 task_io_account_write(ret); 88 89 if (iocb->ki_flags & IOCB_NOWAIT) 90 bio.bi_opf |= REQ_NOWAIT; 91 92 submit_bio_wait(&bio); 93 94 bio_release_pages(&bio, should_dirty); 95 if (unlikely(bio.bi_status)) 96 ret = blk_status_to_errno(bio.bi_status); 97 98 out: 99 if (vecs != inline_vecs) 100 kfree(vecs); 101 102 bio_uninit(&bio); 103 104 return ret; 105 } 106 107 enum { 108 DIO_SHOULD_DIRTY = 1, 109 DIO_IS_SYNC = 2, 110 }; 111 112 struct blkdev_dio { 113 union { 114 struct kiocb *iocb; 115 struct task_struct *waiter; 116 }; 117 size_t size; 118 atomic_t ref; 119 unsigned int flags; 120 struct bio bio ____cacheline_aligned_in_smp; 121 }; 122 123 static struct bio_set blkdev_dio_pool; 124 125 static void blkdev_bio_end_io(struct bio *bio) 126 { 127 struct blkdev_dio *dio = bio->bi_private; 128 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 129 bool is_sync = dio->flags & DIO_IS_SYNC; 130 131 if (bio->bi_status && !dio->bio.bi_status) 132 dio->bio.bi_status = bio->bi_status; 133 134 if (bio_integrity(bio)) 135 bio_integrity_unmap_user(bio); 136 137 if (atomic_dec_and_test(&dio->ref)) { 138 if (!is_sync) { 139 struct kiocb *iocb = dio->iocb; 140 ssize_t ret; 141 142 WRITE_ONCE(iocb->private, NULL); 143 144 if (likely(!dio->bio.bi_status)) { 145 ret = dio->size; 146 iocb->ki_pos += ret; 147 } else { 148 ret = blk_status_to_errno(dio->bio.bi_status); 149 } 150 151 dio->iocb->ki_complete(iocb, ret); 152 bio_put(&dio->bio); 153 } else { 154 struct task_struct *waiter = dio->waiter; 155 156 WRITE_ONCE(dio->waiter, NULL); 157 blk_wake_io_task(waiter); 158 } 159 } 160 161 if (should_dirty) { 162 bio_check_pages_dirty(bio); 163 } else { 164 bio_release_pages(bio, false); 165 bio_put(bio); 166 } 167 } 168 169 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 170 struct block_device *bdev, unsigned int nr_pages) 171 { 172 struct blk_plug plug; 173 struct blkdev_dio *dio; 174 struct bio *bio; 175 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 176 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 177 loff_t pos = iocb->ki_pos; 178 int ret = 0; 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 && user_backed_iter(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_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 210 bio->bi_write_stream = iocb->ki_write_stream; 211 bio->bi_private = dio; 212 bio->bi_end_io = blkdev_bio_end_io; 213 bio->bi_ioprio = iocb->ki_ioprio; 214 215 ret = bio_iov_iter_get_pages(bio, iter); 216 if (unlikely(ret)) { 217 bio->bi_status = BLK_STS_IOERR; 218 bio_endio(bio); 219 break; 220 } 221 if (iocb->ki_flags & IOCB_NOWAIT) { 222 /* 223 * This is nonblocking IO, and we need to allocate 224 * another bio if we have data left to map. As we 225 * cannot guarantee that one of the sub bios will not 226 * fail getting issued FOR NOWAIT and as error results 227 * are coalesced across all of them, be safe and ask for 228 * a retry of this from blocking context. 229 */ 230 if (unlikely(iov_iter_count(iter))) { 231 ret = -EAGAIN; 232 goto fail; 233 } 234 bio->bi_opf |= REQ_NOWAIT; 235 } 236 if (iocb->ki_flags & IOCB_HAS_METADATA) { 237 ret = bio_integrity_map_iter(bio, iocb->private); 238 if (unlikely(ret)) 239 goto fail; 240 } 241 242 if (is_read) { 243 if (dio->flags & DIO_SHOULD_DIRTY) 244 bio_set_pages_dirty(bio); 245 } else { 246 task_io_account_write(bio->bi_iter.bi_size); 247 } 248 dio->size += bio->bi_iter.bi_size; 249 pos += bio->bi_iter.bi_size; 250 251 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 252 if (!nr_pages) { 253 submit_bio(bio); 254 break; 255 } 256 atomic_inc(&dio->ref); 257 submit_bio(bio); 258 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 259 } 260 261 blk_finish_plug(&plug); 262 263 if (!is_sync) 264 return -EIOCBQUEUED; 265 266 for (;;) { 267 set_current_state(TASK_UNINTERRUPTIBLE); 268 if (!READ_ONCE(dio->waiter)) 269 break; 270 blk_io_schedule(); 271 } 272 __set_current_state(TASK_RUNNING); 273 274 if (!ret) 275 ret = blk_status_to_errno(dio->bio.bi_status); 276 if (likely(!ret)) 277 ret = dio->size; 278 279 bio_put(&dio->bio); 280 return ret; 281 fail: 282 bio_release_pages(bio, false); 283 bio_clear_flag(bio, BIO_REFFED); 284 bio_put(bio); 285 blk_finish_plug(&plug); 286 return ret; 287 } 288 289 static void blkdev_bio_end_io_async(struct bio *bio) 290 { 291 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 292 struct kiocb *iocb = dio->iocb; 293 ssize_t ret; 294 295 WRITE_ONCE(iocb->private, NULL); 296 297 if (likely(!bio->bi_status)) { 298 ret = dio->size; 299 iocb->ki_pos += ret; 300 } else { 301 ret = blk_status_to_errno(bio->bi_status); 302 } 303 304 if (bio_integrity(bio)) 305 bio_integrity_unmap_user(bio); 306 307 iocb->ki_complete(iocb, ret); 308 309 if (dio->flags & DIO_SHOULD_DIRTY) { 310 bio_check_pages_dirty(bio); 311 } else { 312 bio_release_pages(bio, false); 313 bio_put(bio); 314 } 315 } 316 317 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 318 struct iov_iter *iter, 319 struct block_device *bdev, 320 unsigned int nr_pages) 321 { 322 bool is_read = iov_iter_rw(iter) == READ; 323 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 324 struct blkdev_dio *dio; 325 struct bio *bio; 326 loff_t pos = iocb->ki_pos; 327 int ret = 0; 328 329 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 330 opf |= REQ_ALLOC_CACHE; 331 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 332 &blkdev_dio_pool); 333 dio = container_of(bio, struct blkdev_dio, bio); 334 dio->flags = 0; 335 dio->iocb = iocb; 336 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 337 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 338 bio->bi_write_stream = iocb->ki_write_stream; 339 bio->bi_end_io = blkdev_bio_end_io_async; 340 bio->bi_ioprio = iocb->ki_ioprio; 341 342 if (iov_iter_is_bvec(iter)) { 343 /* 344 * Users don't rely on the iterator being in any particular 345 * state for async I/O returning -EIOCBQUEUED, hence we can 346 * avoid expensive iov_iter_advance(). Bypass 347 * bio_iov_iter_get_pages() and set the bvec directly. 348 */ 349 bio_iov_bvec_set(bio, iter); 350 } else { 351 ret = bio_iov_iter_get_pages(bio, iter); 352 if (unlikely(ret)) 353 goto out_bio_put; 354 } 355 dio->size = bio->bi_iter.bi_size; 356 357 if (is_read) { 358 if (user_backed_iter(iter)) { 359 dio->flags |= DIO_SHOULD_DIRTY; 360 bio_set_pages_dirty(bio); 361 } 362 } else { 363 task_io_account_write(bio->bi_iter.bi_size); 364 } 365 366 if (iocb->ki_flags & IOCB_HAS_METADATA) { 367 ret = bio_integrity_map_iter(bio, iocb->private); 368 WRITE_ONCE(iocb->private, NULL); 369 if (unlikely(ret)) 370 goto out_bio_put; 371 } 372 373 if (iocb->ki_flags & IOCB_ATOMIC) 374 bio->bi_opf |= REQ_ATOMIC; 375 376 if (iocb->ki_flags & IOCB_NOWAIT) 377 bio->bi_opf |= REQ_NOWAIT; 378 379 if (iocb->ki_flags & IOCB_HIPRI) { 380 bio->bi_opf |= REQ_POLLED; 381 submit_bio(bio); 382 WRITE_ONCE(iocb->private, bio); 383 } else { 384 submit_bio(bio); 385 } 386 return -EIOCBQUEUED; 387 388 out_bio_put: 389 bio_put(bio); 390 return ret; 391 } 392 393 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 394 { 395 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 396 unsigned int nr_pages; 397 398 if (!iov_iter_count(iter)) 399 return 0; 400 401 if (blkdev_dio_invalid(bdev, iocb, iter)) 402 return -EINVAL; 403 404 if (iov_iter_rw(iter) == WRITE) { 405 u16 max_write_streams = bdev_max_write_streams(bdev); 406 407 if (iocb->ki_write_stream) { 408 if (iocb->ki_write_stream > max_write_streams) 409 return -EINVAL; 410 } else if (max_write_streams) { 411 enum rw_hint write_hint = 412 file_inode(iocb->ki_filp)->i_write_hint; 413 414 /* 415 * Just use the write hint as write stream for block 416 * device writes. This assumes no file system is 417 * mounted that would use the streams differently. 418 */ 419 if (write_hint <= max_write_streams) 420 iocb->ki_write_stream = write_hint; 421 } 422 } 423 424 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 425 if (likely(nr_pages <= BIO_MAX_VECS && 426 !(iocb->ki_flags & IOCB_HAS_METADATA))) { 427 if (is_sync_kiocb(iocb)) 428 return __blkdev_direct_IO_simple(iocb, iter, bdev, 429 nr_pages); 430 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages); 431 } else if (iocb->ki_flags & IOCB_ATOMIC) { 432 return -EINVAL; 433 } 434 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages)); 435 } 436 437 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 438 unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 439 { 440 struct block_device *bdev = I_BDEV(inode); 441 loff_t isize = i_size_read(inode); 442 443 if (offset >= isize) 444 return -EIO; 445 446 iomap->bdev = bdev; 447 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev)); 448 iomap->type = IOMAP_MAPPED; 449 iomap->addr = iomap->offset; 450 iomap->length = isize - iomap->offset; 451 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ 452 return 0; 453 } 454 455 static const struct iomap_ops blkdev_iomap_ops = { 456 .iomap_begin = blkdev_iomap_begin, 457 }; 458 459 #ifdef CONFIG_BUFFER_HEAD 460 static int blkdev_get_block(struct inode *inode, sector_t iblock, 461 struct buffer_head *bh, int create) 462 { 463 bh->b_bdev = I_BDEV(inode); 464 bh->b_blocknr = iblock; 465 set_buffer_mapped(bh); 466 return 0; 467 } 468 469 /* 470 * We cannot call mpage_writepages() as it does not take the buffer lock. 471 * We must use block_write_full_folio() directly which holds the buffer 472 * lock. The buffer lock provides the synchronisation with writeback 473 * that filesystems rely on when they use the blockdev's mapping. 474 */ 475 static int blkdev_writepages(struct address_space *mapping, 476 struct writeback_control *wbc) 477 { 478 struct folio *folio = NULL; 479 struct blk_plug plug; 480 int err; 481 482 blk_start_plug(&plug); 483 while ((folio = writeback_iter(mapping, wbc, folio, &err))) 484 err = block_write_full_folio(folio, wbc, blkdev_get_block); 485 blk_finish_plug(&plug); 486 487 return err; 488 } 489 490 static int blkdev_read_folio(struct file *file, struct folio *folio) 491 { 492 return block_read_full_folio(folio, blkdev_get_block); 493 } 494 495 static void blkdev_readahead(struct readahead_control *rac) 496 { 497 mpage_readahead(rac, blkdev_get_block); 498 } 499 500 static int blkdev_write_begin(const struct kiocb *iocb, 501 struct address_space *mapping, loff_t pos, 502 unsigned len, struct folio **foliop, 503 void **fsdata) 504 { 505 return block_write_begin(mapping, pos, len, foliop, blkdev_get_block); 506 } 507 508 static int blkdev_write_end(const struct kiocb *iocb, 509 struct address_space *mapping, 510 loff_t pos, unsigned len, unsigned copied, 511 struct folio *folio, void *fsdata) 512 { 513 int ret; 514 ret = block_write_end(pos, len, copied, folio); 515 516 folio_unlock(folio); 517 folio_put(folio); 518 519 return ret; 520 } 521 522 const struct address_space_operations def_blk_aops = { 523 .dirty_folio = block_dirty_folio, 524 .invalidate_folio = block_invalidate_folio, 525 .read_folio = blkdev_read_folio, 526 .readahead = blkdev_readahead, 527 .writepages = blkdev_writepages, 528 .write_begin = blkdev_write_begin, 529 .write_end = blkdev_write_end, 530 .migrate_folio = buffer_migrate_folio_norefs, 531 .is_dirty_writeback = buffer_check_dirty_writeback, 532 }; 533 #else /* CONFIG_BUFFER_HEAD */ 534 static int blkdev_read_folio(struct file *file, struct folio *folio) 535 { 536 return iomap_read_folio(folio, &blkdev_iomap_ops); 537 } 538 539 static void blkdev_readahead(struct readahead_control *rac) 540 { 541 iomap_readahead(rac, &blkdev_iomap_ops); 542 } 543 544 static ssize_t blkdev_writeback_range(struct iomap_writepage_ctx *wpc, 545 struct folio *folio, u64 offset, unsigned int len, u64 end_pos) 546 { 547 loff_t isize = i_size_read(wpc->inode); 548 549 if (WARN_ON_ONCE(offset >= isize)) 550 return -EIO; 551 552 if (offset < wpc->iomap.offset || 553 offset >= wpc->iomap.offset + wpc->iomap.length) { 554 int error; 555 556 error = blkdev_iomap_begin(wpc->inode, offset, isize - offset, 557 IOMAP_WRITE, &wpc->iomap, NULL); 558 if (error) 559 return error; 560 } 561 562 return iomap_add_to_ioend(wpc, folio, offset, end_pos, len); 563 } 564 565 static const struct iomap_writeback_ops blkdev_writeback_ops = { 566 .writeback_range = blkdev_writeback_range, 567 .writeback_submit = iomap_ioend_writeback_submit, 568 }; 569 570 static int blkdev_writepages(struct address_space *mapping, 571 struct writeback_control *wbc) 572 { 573 struct iomap_writepage_ctx wpc = { 574 .inode = mapping->host, 575 .wbc = wbc, 576 .ops = &blkdev_writeback_ops 577 }; 578 579 return iomap_writepages(&wpc); 580 } 581 582 const struct address_space_operations def_blk_aops = { 583 .dirty_folio = filemap_dirty_folio, 584 .release_folio = iomap_release_folio, 585 .invalidate_folio = iomap_invalidate_folio, 586 .read_folio = blkdev_read_folio, 587 .readahead = blkdev_readahead, 588 .writepages = blkdev_writepages, 589 .is_partially_uptodate = iomap_is_partially_uptodate, 590 .error_remove_folio = generic_error_remove_folio, 591 .migrate_folio = filemap_migrate_folio, 592 }; 593 #endif /* CONFIG_BUFFER_HEAD */ 594 595 /* 596 * for a block special file file_inode(file)->i_size is zero 597 * so we compute the size by hand (just as in block_read/write above) 598 */ 599 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 600 { 601 struct inode *bd_inode = bdev_file_inode(file); 602 loff_t retval; 603 604 inode_lock(bd_inode); 605 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 606 inode_unlock(bd_inode); 607 return retval; 608 } 609 610 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 611 int datasync) 612 { 613 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 614 int error; 615 616 error = file_write_and_wait_range(filp, start, end); 617 if (error) 618 return error; 619 620 /* 621 * There is no need to serialise calls to blkdev_issue_flush with 622 * i_mutex and doing so causes performance issues with concurrent 623 * O_SYNC writers to a block device. 624 */ 625 error = blkdev_issue_flush(bdev); 626 if (error == -EOPNOTSUPP) 627 error = 0; 628 629 return error; 630 } 631 632 /** 633 * file_to_blk_mode - get block open flags from file flags 634 * @file: file whose open flags should be converted 635 * 636 * Look at file open flags and generate corresponding block open flags from 637 * them. The function works both for file just being open (e.g. during ->open 638 * callback) and for file that is already open. This is actually non-trivial 639 * (see comment in the function). 640 */ 641 blk_mode_t file_to_blk_mode(struct file *file) 642 { 643 blk_mode_t mode = 0; 644 645 if (file->f_mode & FMODE_READ) 646 mode |= BLK_OPEN_READ; 647 if (file->f_mode & FMODE_WRITE) 648 mode |= BLK_OPEN_WRITE; 649 /* 650 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data 651 * to determine whether the open was exclusive for already open files. 652 */ 653 if (file->private_data) 654 mode |= BLK_OPEN_EXCL; 655 else if (file->f_flags & O_EXCL) 656 mode |= BLK_OPEN_EXCL; 657 if (file->f_flags & O_NDELAY) 658 mode |= BLK_OPEN_NDELAY; 659 660 /* 661 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 662 * driver has historically allowed ioctls as if the file was opened for 663 * writing, but does not allow and actual reads or writes. 664 */ 665 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 666 mode |= BLK_OPEN_WRITE_IOCTL; 667 668 return mode; 669 } 670 671 static int blkdev_open(struct inode *inode, struct file *filp) 672 { 673 struct block_device *bdev; 674 blk_mode_t mode; 675 int ret; 676 677 mode = file_to_blk_mode(filp); 678 /* Use the file as the holder. */ 679 if (mode & BLK_OPEN_EXCL) 680 filp->private_data = filp; 681 ret = bdev_permission(inode->i_rdev, mode, filp->private_data); 682 if (ret) 683 return ret; 684 685 bdev = blkdev_get_no_open(inode->i_rdev, true); 686 if (!bdev) 687 return -ENXIO; 688 689 if (bdev_can_atomic_write(bdev)) 690 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE; 691 if (blk_get_integrity(bdev->bd_disk)) 692 filp->f_mode |= FMODE_HAS_METADATA; 693 694 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp); 695 if (ret) 696 blkdev_put_no_open(bdev); 697 return ret; 698 } 699 700 static int blkdev_release(struct inode *inode, struct file *filp) 701 { 702 bdev_release(filp); 703 return 0; 704 } 705 706 static ssize_t 707 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from) 708 { 709 size_t count = iov_iter_count(from); 710 ssize_t written; 711 712 written = kiocb_invalidate_pages(iocb, count); 713 if (written) { 714 if (written == -EBUSY) 715 return 0; 716 return written; 717 } 718 719 written = blkdev_direct_IO(iocb, from); 720 if (written > 0) { 721 kiocb_invalidate_post_direct_write(iocb, count); 722 iocb->ki_pos += written; 723 count -= written; 724 } 725 if (written != -EIOCBQUEUED) 726 iov_iter_revert(from, count - iov_iter_count(from)); 727 return written; 728 } 729 730 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from) 731 { 732 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL, 733 NULL); 734 } 735 736 /* 737 * Write data to the block device. Only intended for the block device itself 738 * and the raw driver which basically is a fake block device. 739 * 740 * Does not take i_mutex for the write and thus is not for general purpose 741 * use. 742 */ 743 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 744 { 745 struct file *file = iocb->ki_filp; 746 struct inode *bd_inode = bdev_file_inode(file); 747 struct block_device *bdev = I_BDEV(bd_inode); 748 bool atomic = iocb->ki_flags & IOCB_ATOMIC; 749 loff_t size = bdev_nr_bytes(bdev); 750 size_t shorted = 0; 751 ssize_t ret; 752 753 if (bdev_read_only(bdev)) 754 return -EPERM; 755 756 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 757 return -ETXTBSY; 758 759 if (!iov_iter_count(from)) 760 return 0; 761 762 if (iocb->ki_pos >= size) 763 return -ENOSPC; 764 765 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 766 return -EOPNOTSUPP; 767 768 if (atomic) { 769 ret = generic_atomic_write_valid(iocb, from); 770 if (ret) 771 return ret; 772 } 773 774 size -= iocb->ki_pos; 775 if (iov_iter_count(from) > size) { 776 if (atomic) 777 return -EINVAL; 778 shorted = iov_iter_count(from) - size; 779 iov_iter_truncate(from, size); 780 } 781 782 ret = file_update_time(file); 783 if (ret) 784 return ret; 785 786 if (iocb->ki_flags & IOCB_DIRECT) { 787 ret = blkdev_direct_write(iocb, from); 788 if (ret >= 0 && iov_iter_count(from)) 789 ret = direct_write_fallback(iocb, from, ret, 790 blkdev_buffered_write(iocb, from)); 791 } else { 792 /* 793 * Take i_rwsem and invalidate_lock to avoid racing with 794 * set_blocksize changing i_blkbits/folio order and punching 795 * out the pagecache. 796 */ 797 inode_lock_shared(bd_inode); 798 ret = blkdev_buffered_write(iocb, from); 799 inode_unlock_shared(bd_inode); 800 } 801 802 if (ret > 0) 803 ret = generic_write_sync(iocb, ret); 804 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 805 return ret; 806 } 807 808 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 809 { 810 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp); 811 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 812 loff_t size = bdev_nr_bytes(bdev); 813 loff_t pos = iocb->ki_pos; 814 size_t shorted = 0; 815 ssize_t ret = 0; 816 size_t count; 817 818 if (unlikely(pos + iov_iter_count(to) > size)) { 819 if (pos >= size) 820 return 0; 821 size -= pos; 822 shorted = iov_iter_count(to) - size; 823 iov_iter_truncate(to, size); 824 } 825 826 count = iov_iter_count(to); 827 if (!count) 828 goto reexpand; /* skip atime */ 829 830 if (iocb->ki_flags & IOCB_DIRECT) { 831 ret = kiocb_write_and_wait(iocb, count); 832 if (ret < 0) 833 goto reexpand; 834 file_accessed(iocb->ki_filp); 835 836 ret = blkdev_direct_IO(iocb, to); 837 if (ret > 0) { 838 iocb->ki_pos += ret; 839 count -= ret; 840 } 841 if (ret != -EIOCBQUEUED) 842 iov_iter_revert(to, count - iov_iter_count(to)); 843 if (ret < 0 || !count) 844 goto reexpand; 845 } 846 847 /* 848 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize 849 * changing i_blkbits/folio order and punching out the pagecache. 850 */ 851 inode_lock_shared(bd_inode); 852 ret = filemap_read(iocb, to, ret); 853 inode_unlock_shared(bd_inode); 854 855 reexpand: 856 if (unlikely(shorted)) 857 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 858 return ret; 859 } 860 861 #define BLKDEV_FALLOC_FL_SUPPORTED \ 862 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 863 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES) 864 865 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 866 loff_t len) 867 { 868 struct inode *inode = bdev_file_inode(file); 869 struct block_device *bdev = I_BDEV(inode); 870 loff_t end = start + len - 1; 871 loff_t isize; 872 unsigned int flags; 873 int error; 874 875 /* Fail if we don't recognize the flags. */ 876 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 877 return -EOPNOTSUPP; 878 /* 879 * Don't allow writing zeroes if the device does not enable the 880 * unmap write zeroes operation. 881 */ 882 if ((mode & FALLOC_FL_WRITE_ZEROES) && 883 !bdev_write_zeroes_unmap_sectors(bdev)) 884 return -EOPNOTSUPP; 885 886 /* Don't go off the end of the device. */ 887 isize = bdev_nr_bytes(bdev); 888 if (start >= isize) 889 return -EINVAL; 890 if (end >= isize) { 891 if (mode & FALLOC_FL_KEEP_SIZE) { 892 len = isize - start; 893 end = start + len - 1; 894 } else 895 return -EINVAL; 896 } 897 898 /* 899 * Don't allow IO that isn't aligned to logical block size. 900 */ 901 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 902 return -EINVAL; 903 904 inode_lock(inode); 905 filemap_invalidate_lock(inode->i_mapping); 906 907 switch (mode) { 908 case FALLOC_FL_ZERO_RANGE: 909 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 910 flags = BLKDEV_ZERO_NOUNMAP; 911 break; 912 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 913 flags = BLKDEV_ZERO_NOFALLBACK; 914 break; 915 case FALLOC_FL_WRITE_ZEROES: 916 flags = 0; 917 break; 918 default: 919 error = -EOPNOTSUPP; 920 goto fail; 921 } 922 923 /* 924 * Invalidate the page cache, including dirty pages, for valid 925 * de-allocate mode calls to fallocate(). 926 */ 927 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 928 if (error) 929 goto fail; 930 931 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 932 len >> SECTOR_SHIFT, GFP_KERNEL, flags); 933 fail: 934 filemap_invalidate_unlock(inode->i_mapping); 935 inode_unlock(inode); 936 return error; 937 } 938 939 static int blkdev_mmap_prepare(struct vm_area_desc *desc) 940 { 941 struct file *file = desc->file; 942 943 if (bdev_read_only(I_BDEV(bdev_file_inode(file)))) 944 return generic_file_readonly_mmap_prepare(desc); 945 946 return generic_file_mmap_prepare(desc); 947 } 948 949 const struct file_operations def_blk_fops = { 950 .open = blkdev_open, 951 .release = blkdev_release, 952 .llseek = blkdev_llseek, 953 .read_iter = blkdev_read_iter, 954 .write_iter = blkdev_write_iter, 955 .iopoll = iocb_bio_iopoll, 956 .mmap_prepare = blkdev_mmap_prepare, 957 .fsync = blkdev_fsync, 958 .unlocked_ioctl = blkdev_ioctl, 959 #ifdef CONFIG_COMPAT 960 .compat_ioctl = compat_blkdev_ioctl, 961 #endif 962 .splice_read = filemap_splice_read, 963 .splice_write = iter_file_splice_write, 964 .fallocate = blkdev_fallocate, 965 .uring_cmd = blkdev_uring_cmd, 966 .fop_flags = FOP_BUFFER_RASYNC, 967 }; 968 969 static __init int blkdev_init(void) 970 { 971 return bioset_init(&blkdev_dio_pool, 4, 972 offsetof(struct blkdev_dio, bio), 973 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 974 } 975 module_init(blkdev_init); 976