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_array(nr_pages, sizeof(struct bio_vec), 69 GFP_KERNEL); 70 if (!vecs) 71 return -ENOMEM; 72 } 73 74 if (iov_iter_rw(iter) == READ) { 75 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ); 76 if (user_backed_iter(iter)) 77 should_dirty = true; 78 } else { 79 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb)); 80 } 81 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 82 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 83 bio.bi_write_stream = iocb->ki_write_stream; 84 bio.bi_ioprio = iocb->ki_ioprio; 85 if (iocb->ki_flags & IOCB_ATOMIC) 86 bio.bi_opf |= REQ_ATOMIC; 87 88 ret = blkdev_iov_iter_get_pages(&bio, iter, bdev); 89 if (unlikely(ret)) 90 goto out; 91 ret = bio.bi_iter.bi_size; 92 93 if (iov_iter_rw(iter) == WRITE) 94 task_io_account_write(ret); 95 96 if (iocb->ki_flags & IOCB_NOWAIT) 97 bio.bi_opf |= REQ_NOWAIT; 98 99 submit_bio_wait(&bio); 100 101 bio_release_pages(&bio, should_dirty); 102 if (unlikely(bio.bi_status)) 103 ret = blk_status_to_errno(bio.bi_status); 104 105 out: 106 if (vecs != inline_vecs) 107 kfree(vecs); 108 109 bio_uninit(&bio); 110 111 return ret; 112 } 113 114 enum { 115 DIO_SHOULD_DIRTY = 1, 116 DIO_IS_SYNC = 2, 117 }; 118 119 struct blkdev_dio { 120 union { 121 struct kiocb *iocb; 122 struct task_struct *waiter; 123 }; 124 size_t size; 125 atomic_t ref; 126 unsigned int flags; 127 struct bio bio ____cacheline_aligned_in_smp; 128 }; 129 130 static struct bio_set blkdev_dio_pool; 131 132 static void blkdev_bio_end_io(struct bio *bio) 133 { 134 struct blkdev_dio *dio = bio->bi_private; 135 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 136 bool is_sync = dio->flags & DIO_IS_SYNC; 137 138 if (bio->bi_status && !dio->bio.bi_status) 139 dio->bio.bi_status = bio->bi_status; 140 141 if (bio_integrity(bio)) 142 bio_integrity_unmap_user(bio); 143 144 if (atomic_dec_and_test(&dio->ref)) { 145 if (!is_sync) { 146 struct kiocb *iocb = dio->iocb; 147 ssize_t ret; 148 149 WRITE_ONCE(iocb->private, NULL); 150 151 if (likely(!dio->bio.bi_status)) { 152 ret = dio->size; 153 iocb->ki_pos += ret; 154 } else { 155 ret = blk_status_to_errno(dio->bio.bi_status); 156 } 157 158 dio->iocb->ki_complete(iocb, ret); 159 bio_put(&dio->bio); 160 } else { 161 struct task_struct *waiter = dio->waiter; 162 163 WRITE_ONCE(dio->waiter, NULL); 164 blk_wake_io_task(waiter); 165 } 166 } 167 168 if (should_dirty) { 169 bio_check_pages_dirty(bio); 170 } else { 171 bio_release_pages(bio, false); 172 bio_put(bio); 173 } 174 } 175 176 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 177 struct block_device *bdev, unsigned int nr_pages) 178 { 179 struct blk_plug plug; 180 struct blkdev_dio *dio; 181 struct bio *bio; 182 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 183 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 184 loff_t pos = iocb->ki_pos; 185 int ret = 0; 186 187 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 188 &blkdev_dio_pool); 189 dio = container_of(bio, struct blkdev_dio, bio); 190 atomic_set(&dio->ref, 1); 191 /* 192 * Grab an extra reference to ensure the dio structure which is embedded 193 * into the first bio stays around. 194 */ 195 bio_get(bio); 196 197 is_sync = is_sync_kiocb(iocb); 198 if (is_sync) { 199 dio->flags = DIO_IS_SYNC; 200 dio->waiter = current; 201 } else { 202 dio->flags = 0; 203 dio->iocb = iocb; 204 } 205 206 dio->size = 0; 207 if (is_read && user_backed_iter(iter)) 208 dio->flags |= DIO_SHOULD_DIRTY; 209 210 blk_start_plug(&plug); 211 212 for (;;) { 213 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 214 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 215 bio->bi_write_stream = iocb->ki_write_stream; 216 bio->bi_private = dio; 217 bio->bi_end_io = blkdev_bio_end_io; 218 bio->bi_ioprio = iocb->ki_ioprio; 219 220 ret = blkdev_iov_iter_get_pages(bio, iter, bdev); 221 if (unlikely(ret)) { 222 bio->bi_status = BLK_STS_IOERR; 223 bio_endio(bio); 224 break; 225 } 226 if (iocb->ki_flags & IOCB_NOWAIT) { 227 /* 228 * This is nonblocking IO, and we need to allocate 229 * another bio if we have data left to map. As we 230 * cannot guarantee that one of the sub bios will not 231 * fail getting issued FOR NOWAIT and as error results 232 * are coalesced across all of them, be safe and ask for 233 * a retry of this from blocking context. 234 */ 235 if (unlikely(iov_iter_count(iter))) { 236 ret = -EAGAIN; 237 goto fail; 238 } 239 bio->bi_opf |= REQ_NOWAIT; 240 } 241 if (iocb->ki_flags & IOCB_HAS_METADATA) { 242 ret = bio_integrity_map_iter(bio, iocb->private); 243 if (unlikely(ret)) 244 goto fail; 245 } 246 247 if (is_read) { 248 if (dio->flags & DIO_SHOULD_DIRTY) 249 bio_set_pages_dirty(bio); 250 } else { 251 task_io_account_write(bio->bi_iter.bi_size); 252 } 253 dio->size += bio->bi_iter.bi_size; 254 pos += bio->bi_iter.bi_size; 255 256 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 257 if (!nr_pages) { 258 submit_bio(bio); 259 break; 260 } 261 atomic_inc(&dio->ref); 262 submit_bio(bio); 263 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 264 } 265 266 blk_finish_plug(&plug); 267 268 if (!is_sync) 269 return -EIOCBQUEUED; 270 271 for (;;) { 272 set_current_state(TASK_UNINTERRUPTIBLE); 273 if (!READ_ONCE(dio->waiter)) 274 break; 275 blk_io_schedule(); 276 } 277 __set_current_state(TASK_RUNNING); 278 279 if (!ret) 280 ret = blk_status_to_errno(dio->bio.bi_status); 281 if (likely(!ret)) 282 ret = dio->size; 283 284 bio_put(&dio->bio); 285 return ret; 286 fail: 287 bio_release_pages(bio, false); 288 bio_clear_flag(bio, BIO_REFFED); 289 bio_put(bio); 290 blk_finish_plug(&plug); 291 return ret; 292 } 293 294 static void blkdev_bio_end_io_async(struct bio *bio) 295 { 296 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 297 struct kiocb *iocb = dio->iocb; 298 ssize_t ret; 299 300 WRITE_ONCE(iocb->private, NULL); 301 302 if (likely(!bio->bi_status)) { 303 ret = dio->size; 304 iocb->ki_pos += ret; 305 } else { 306 ret = blk_status_to_errno(bio->bi_status); 307 } 308 309 if (bio_integrity(bio)) 310 bio_integrity_unmap_user(bio); 311 312 iocb->ki_complete(iocb, ret); 313 314 if (dio->flags & DIO_SHOULD_DIRTY) { 315 bio_check_pages_dirty(bio); 316 } else { 317 bio_release_pages(bio, false); 318 bio_put(bio); 319 } 320 } 321 322 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 323 struct iov_iter *iter, 324 struct block_device *bdev, 325 unsigned int nr_pages) 326 { 327 bool is_read = iov_iter_rw(iter) == READ; 328 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 329 struct blkdev_dio *dio; 330 struct bio *bio; 331 loff_t pos = iocb->ki_pos; 332 int ret = 0; 333 334 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 335 &blkdev_dio_pool); 336 dio = container_of(bio, struct blkdev_dio, bio); 337 dio->flags = 0; 338 dio->iocb = iocb; 339 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 340 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 341 bio->bi_write_stream = iocb->ki_write_stream; 342 bio->bi_end_io = blkdev_bio_end_io_async; 343 bio->bi_ioprio = iocb->ki_ioprio; 344 345 if (iov_iter_is_bvec(iter)) { 346 /* 347 * Users don't rely on the iterator being in any particular 348 * state for async I/O returning -EIOCBQUEUED, hence we can 349 * avoid expensive iov_iter_advance(). Bypass 350 * bio_iov_iter_get_pages() and set the bvec directly. 351 */ 352 bio_iov_bvec_set(bio, iter); 353 } else { 354 ret = blkdev_iov_iter_get_pages(bio, iter, bdev); 355 if (unlikely(ret)) 356 goto out_bio_put; 357 } 358 dio->size = bio->bi_iter.bi_size; 359 360 if (is_read) { 361 if (user_backed_iter(iter)) { 362 dio->flags |= DIO_SHOULD_DIRTY; 363 bio_set_pages_dirty(bio); 364 } 365 } else { 366 task_io_account_write(bio->bi_iter.bi_size); 367 } 368 369 if (iocb->ki_flags & IOCB_HAS_METADATA) { 370 ret = bio_integrity_map_iter(bio, iocb->private); 371 WRITE_ONCE(iocb->private, NULL); 372 if (unlikely(ret)) 373 goto out_bio_put; 374 } 375 376 if (iocb->ki_flags & IOCB_ATOMIC) 377 bio->bi_opf |= REQ_ATOMIC; 378 379 if (iocb->ki_flags & IOCB_NOWAIT) 380 bio->bi_opf |= REQ_NOWAIT; 381 382 if (iocb->ki_flags & IOCB_HIPRI) { 383 bio->bi_opf |= REQ_POLLED; 384 submit_bio(bio); 385 WRITE_ONCE(iocb->private, bio); 386 } else { 387 submit_bio(bio); 388 } 389 return -EIOCBQUEUED; 390 391 out_bio_put: 392 bio_put(bio); 393 return ret; 394 } 395 396 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 397 { 398 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 399 unsigned int nr_pages; 400 401 if (!iov_iter_count(iter)) 402 return 0; 403 404 if (blkdev_dio_invalid(bdev, iocb, iter)) 405 return -EINVAL; 406 407 if (iov_iter_rw(iter) == WRITE) { 408 u16 max_write_streams = bdev_max_write_streams(bdev); 409 410 if (iocb->ki_write_stream) { 411 if (iocb->ki_write_stream > max_write_streams) 412 return -EINVAL; 413 } else if (max_write_streams) { 414 enum rw_hint write_hint = 415 file_inode(iocb->ki_filp)->i_write_hint; 416 417 /* 418 * Just use the write hint as write stream for block 419 * device writes. This assumes no file system is 420 * mounted that would use the streams differently. 421 */ 422 if (write_hint <= max_write_streams) 423 iocb->ki_write_stream = write_hint; 424 } 425 } 426 427 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 428 if (likely(nr_pages <= BIO_MAX_VECS && 429 !(iocb->ki_flags & IOCB_HAS_METADATA))) { 430 if (is_sync_kiocb(iocb)) 431 return __blkdev_direct_IO_simple(iocb, iter, bdev, 432 nr_pages); 433 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages); 434 } else if (iocb->ki_flags & IOCB_ATOMIC) { 435 return -EINVAL; 436 } 437 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages)); 438 } 439 440 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 441 unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 442 { 443 struct block_device *bdev = I_BDEV(inode); 444 loff_t isize = i_size_read(inode); 445 446 if (offset >= isize) 447 return -EIO; 448 449 iomap->bdev = bdev; 450 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev)); 451 iomap->type = IOMAP_MAPPED; 452 iomap->addr = iomap->offset; 453 iomap->length = isize - iomap->offset; 454 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ 455 return 0; 456 } 457 458 static const struct iomap_ops blkdev_iomap_ops = { 459 .iomap_begin = blkdev_iomap_begin, 460 }; 461 462 #ifdef CONFIG_BUFFER_HEAD 463 static int blkdev_get_block(struct inode *inode, sector_t iblock, 464 struct buffer_head *bh, int create) 465 { 466 bh->b_bdev = I_BDEV(inode); 467 bh->b_blocknr = iblock; 468 set_buffer_mapped(bh); 469 return 0; 470 } 471 472 /* 473 * We cannot call mpage_writepages() as it does not take the buffer lock. 474 * We must use block_write_full_folio() directly which holds the buffer 475 * lock. The buffer lock provides the synchronisation with writeback 476 * that filesystems rely on when they use the blockdev's mapping. 477 */ 478 static int blkdev_writepages(struct address_space *mapping, 479 struct writeback_control *wbc) 480 { 481 struct folio *folio = NULL; 482 struct blk_plug plug; 483 int err; 484 485 blk_start_plug(&plug); 486 while ((folio = writeback_iter(mapping, wbc, folio, &err))) 487 err = block_write_full_folio(folio, wbc, blkdev_get_block); 488 blk_finish_plug(&plug); 489 490 return err; 491 } 492 493 static int blkdev_read_folio(struct file *file, struct folio *folio) 494 { 495 return block_read_full_folio(folio, blkdev_get_block); 496 } 497 498 static void blkdev_readahead(struct readahead_control *rac) 499 { 500 mpage_readahead(rac, blkdev_get_block); 501 } 502 503 static int blkdev_write_begin(const struct kiocb *iocb, 504 struct address_space *mapping, loff_t pos, 505 unsigned len, struct folio **foliop, 506 void **fsdata) 507 { 508 return block_write_begin(mapping, pos, len, foliop, blkdev_get_block); 509 } 510 511 static int blkdev_write_end(const struct kiocb *iocb, 512 struct address_space *mapping, 513 loff_t pos, unsigned len, unsigned copied, 514 struct folio *folio, void *fsdata) 515 { 516 int ret; 517 ret = block_write_end(pos, len, copied, folio); 518 519 folio_unlock(folio); 520 folio_put(folio); 521 522 return ret; 523 } 524 525 const struct address_space_operations def_blk_aops = { 526 .dirty_folio = block_dirty_folio, 527 .invalidate_folio = block_invalidate_folio, 528 .read_folio = blkdev_read_folio, 529 .readahead = blkdev_readahead, 530 .writepages = blkdev_writepages, 531 .write_begin = blkdev_write_begin, 532 .write_end = blkdev_write_end, 533 .migrate_folio = buffer_migrate_folio_norefs, 534 .is_dirty_writeback = buffer_check_dirty_writeback, 535 }; 536 #else /* CONFIG_BUFFER_HEAD */ 537 static int blkdev_read_folio(struct file *file, struct folio *folio) 538 { 539 iomap_bio_read_folio(folio, &blkdev_iomap_ops); 540 return 0; 541 } 542 543 static void blkdev_readahead(struct readahead_control *rac) 544 { 545 iomap_bio_readahead(rac, &blkdev_iomap_ops); 546 } 547 548 static ssize_t blkdev_writeback_range(struct iomap_writepage_ctx *wpc, 549 struct folio *folio, u64 offset, unsigned int len, u64 end_pos) 550 { 551 loff_t isize = i_size_read(wpc->inode); 552 553 if (WARN_ON_ONCE(offset >= isize)) 554 return -EIO; 555 556 if (offset < wpc->iomap.offset || 557 offset >= wpc->iomap.offset + wpc->iomap.length) { 558 int error; 559 560 error = blkdev_iomap_begin(wpc->inode, offset, isize - offset, 561 IOMAP_WRITE, &wpc->iomap, NULL); 562 if (error) 563 return error; 564 } 565 566 return iomap_add_to_ioend(wpc, folio, offset, end_pos, len); 567 } 568 569 static const struct iomap_writeback_ops blkdev_writeback_ops = { 570 .writeback_range = blkdev_writeback_range, 571 .writeback_submit = iomap_ioend_writeback_submit, 572 }; 573 574 static int blkdev_writepages(struct address_space *mapping, 575 struct writeback_control *wbc) 576 { 577 struct iomap_writepage_ctx wpc = { 578 .inode = mapping->host, 579 .wbc = wbc, 580 .ops = &blkdev_writeback_ops 581 }; 582 583 return iomap_writepages(&wpc); 584 } 585 586 const struct address_space_operations def_blk_aops = { 587 .dirty_folio = filemap_dirty_folio, 588 .release_folio = iomap_release_folio, 589 .invalidate_folio = iomap_invalidate_folio, 590 .read_folio = blkdev_read_folio, 591 .readahead = blkdev_readahead, 592 .writepages = blkdev_writepages, 593 .is_partially_uptodate = iomap_is_partially_uptodate, 594 .error_remove_folio = generic_error_remove_folio, 595 .migrate_folio = filemap_migrate_folio, 596 }; 597 #endif /* CONFIG_BUFFER_HEAD */ 598 599 /* 600 * for a block special file file_inode(file)->i_size is zero 601 * so we compute the size by hand (just as in block_read/write above) 602 */ 603 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 604 { 605 struct inode *bd_inode = bdev_file_inode(file); 606 loff_t retval; 607 608 inode_lock(bd_inode); 609 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 610 inode_unlock(bd_inode); 611 return retval; 612 } 613 614 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 615 int datasync) 616 { 617 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 618 int error; 619 620 error = file_write_and_wait_range(filp, start, end); 621 if (error) 622 return error; 623 624 /* 625 * There is no need to serialise calls to blkdev_issue_flush with 626 * i_mutex and doing so causes performance issues with concurrent 627 * O_SYNC writers to a block device. 628 */ 629 error = blkdev_issue_flush(bdev); 630 if (error == -EOPNOTSUPP) 631 error = 0; 632 633 return error; 634 } 635 636 /** 637 * file_to_blk_mode - get block open flags from file flags 638 * @file: file whose open flags should be converted 639 * 640 * Look at file open flags and generate corresponding block open flags from 641 * them. The function works both for file just being open (e.g. during ->open 642 * callback) and for file that is already open. This is actually non-trivial 643 * (see comment in the function). 644 */ 645 blk_mode_t file_to_blk_mode(struct file *file) 646 { 647 blk_mode_t mode = 0; 648 649 if (file->f_mode & FMODE_READ) 650 mode |= BLK_OPEN_READ; 651 if (file->f_mode & FMODE_WRITE) 652 mode |= BLK_OPEN_WRITE; 653 /* 654 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data 655 * to determine whether the open was exclusive for already open files. 656 */ 657 if (file->private_data) 658 mode |= BLK_OPEN_EXCL; 659 else if (file->f_flags & O_EXCL) 660 mode |= BLK_OPEN_EXCL; 661 if (file->f_flags & O_NDELAY) 662 mode |= BLK_OPEN_NDELAY; 663 664 /* 665 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 666 * driver has historically allowed ioctls as if the file was opened for 667 * writing, but does not allow and actual reads or writes. 668 */ 669 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 670 mode |= BLK_OPEN_WRITE_IOCTL; 671 672 return mode; 673 } 674 675 static int blkdev_open(struct inode *inode, struct file *filp) 676 { 677 struct block_device *bdev; 678 blk_mode_t mode; 679 int ret; 680 681 mode = file_to_blk_mode(filp); 682 /* Use the file as the holder. */ 683 if (mode & BLK_OPEN_EXCL) 684 filp->private_data = filp; 685 ret = bdev_permission(inode->i_rdev, mode, filp->private_data); 686 if (ret) 687 return ret; 688 689 bdev = blkdev_get_no_open(inode->i_rdev, true); 690 if (!bdev) 691 return -ENXIO; 692 693 if (bdev_can_atomic_write(bdev)) 694 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE; 695 if (blk_get_integrity(bdev->bd_disk)) 696 filp->f_mode |= FMODE_HAS_METADATA; 697 698 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp); 699 if (ret) 700 blkdev_put_no_open(bdev); 701 return ret; 702 } 703 704 static int blkdev_release(struct inode *inode, struct file *filp) 705 { 706 bdev_release(filp); 707 return 0; 708 } 709 710 static ssize_t 711 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from) 712 { 713 size_t count = iov_iter_count(from); 714 ssize_t written; 715 716 written = kiocb_invalidate_pages(iocb, count); 717 if (written) { 718 if (written == -EBUSY) 719 return 0; 720 return written; 721 } 722 723 written = blkdev_direct_IO(iocb, from); 724 if (written > 0) { 725 kiocb_invalidate_post_direct_write(iocb, count); 726 iocb->ki_pos += written; 727 count -= written; 728 } 729 if (written != -EIOCBQUEUED) 730 iov_iter_revert(from, count - iov_iter_count(from)); 731 return written; 732 } 733 734 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from) 735 { 736 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL, 737 NULL); 738 } 739 740 /* 741 * Write data to the block device. Only intended for the block device itself 742 * and the raw driver which basically is a fake block device. 743 * 744 * Does not take i_mutex for the write and thus is not for general purpose 745 * use. 746 */ 747 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 748 { 749 struct file *file = iocb->ki_filp; 750 struct inode *bd_inode = bdev_file_inode(file); 751 struct block_device *bdev = I_BDEV(bd_inode); 752 bool atomic = iocb->ki_flags & IOCB_ATOMIC; 753 loff_t size = bdev_nr_bytes(bdev); 754 size_t shorted = 0; 755 ssize_t ret; 756 757 if (bdev_read_only(bdev)) 758 return -EPERM; 759 760 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 761 return -ETXTBSY; 762 763 if (!iov_iter_count(from)) 764 return 0; 765 766 if (iocb->ki_pos >= size) 767 return -ENOSPC; 768 769 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 770 return -EOPNOTSUPP; 771 772 if (atomic) { 773 ret = generic_atomic_write_valid(iocb, from); 774 if (ret) 775 return ret; 776 } 777 778 size -= iocb->ki_pos; 779 if (iov_iter_count(from) > size) { 780 if (atomic) 781 return -EINVAL; 782 shorted = iov_iter_count(from) - size; 783 iov_iter_truncate(from, size); 784 } 785 786 ret = file_update_time(file); 787 if (ret) 788 return ret; 789 790 if (iocb->ki_flags & IOCB_DIRECT) { 791 ret = blkdev_direct_write(iocb, from); 792 if (ret >= 0 && iov_iter_count(from)) 793 ret = direct_write_fallback(iocb, from, ret, 794 blkdev_buffered_write(iocb, from)); 795 } else { 796 /* 797 * Take i_rwsem and invalidate_lock to avoid racing with 798 * set_blocksize changing i_blkbits/folio order and punching 799 * out the pagecache. 800 */ 801 inode_lock_shared(bd_inode); 802 ret = blkdev_buffered_write(iocb, from); 803 inode_unlock_shared(bd_inode); 804 } 805 806 if (ret > 0) 807 ret = generic_write_sync(iocb, ret); 808 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 809 return ret; 810 } 811 812 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 813 { 814 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp); 815 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 816 loff_t size = bdev_nr_bytes(bdev); 817 loff_t pos = iocb->ki_pos; 818 size_t shorted = 0; 819 ssize_t ret = 0; 820 size_t count; 821 822 if (unlikely(pos + iov_iter_count(to) > size)) { 823 if (pos >= size) 824 return 0; 825 size -= pos; 826 shorted = iov_iter_count(to) - size; 827 iov_iter_truncate(to, size); 828 } 829 830 count = iov_iter_count(to); 831 if (!count) 832 goto reexpand; /* skip atime */ 833 834 if (iocb->ki_flags & IOCB_DIRECT) { 835 ret = kiocb_write_and_wait(iocb, count); 836 if (ret < 0) 837 goto reexpand; 838 file_accessed(iocb->ki_filp); 839 840 ret = blkdev_direct_IO(iocb, to); 841 if (ret > 0) { 842 iocb->ki_pos += ret; 843 count -= ret; 844 } 845 if (ret != -EIOCBQUEUED) 846 iov_iter_revert(to, count - iov_iter_count(to)); 847 if (ret < 0 || !count) 848 goto reexpand; 849 } 850 851 /* 852 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize 853 * changing i_blkbits/folio order and punching out the pagecache. 854 */ 855 inode_lock_shared(bd_inode); 856 ret = filemap_read(iocb, to, ret); 857 inode_unlock_shared(bd_inode); 858 859 reexpand: 860 if (unlikely(shorted)) 861 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 862 return ret; 863 } 864 865 #define BLKDEV_FALLOC_FL_SUPPORTED \ 866 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 867 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES) 868 869 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 870 loff_t len) 871 { 872 struct inode *inode = bdev_file_inode(file); 873 struct block_device *bdev = I_BDEV(inode); 874 loff_t end = start + len - 1; 875 loff_t isize; 876 unsigned int flags; 877 int error; 878 879 /* Fail if we don't recognize the flags. */ 880 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 881 return -EOPNOTSUPP; 882 /* 883 * Don't allow writing zeroes if the device does not enable the 884 * unmap write zeroes operation. 885 */ 886 if ((mode & FALLOC_FL_WRITE_ZEROES) && 887 !bdev_write_zeroes_unmap_sectors(bdev)) 888 return -EOPNOTSUPP; 889 890 /* Don't go off the end of the device. */ 891 isize = bdev_nr_bytes(bdev); 892 if (start >= isize) 893 return -EINVAL; 894 if (end >= isize) { 895 if (mode & FALLOC_FL_KEEP_SIZE) { 896 len = isize - start; 897 end = start + len - 1; 898 } else 899 return -EINVAL; 900 } 901 902 /* 903 * Don't allow IO that isn't aligned to logical block size. 904 */ 905 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 906 return -EINVAL; 907 908 inode_lock(inode); 909 filemap_invalidate_lock(inode->i_mapping); 910 911 switch (mode) { 912 case FALLOC_FL_ZERO_RANGE: 913 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 914 flags = BLKDEV_ZERO_NOUNMAP; 915 break; 916 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 917 flags = BLKDEV_ZERO_NOFALLBACK; 918 break; 919 case FALLOC_FL_WRITE_ZEROES: 920 flags = 0; 921 break; 922 default: 923 error = -EOPNOTSUPP; 924 goto fail; 925 } 926 927 /* 928 * Invalidate the page cache, including dirty pages, for valid 929 * de-allocate mode calls to fallocate(). 930 */ 931 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 932 if (error) 933 goto fail; 934 935 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 936 len >> SECTOR_SHIFT, GFP_KERNEL, flags); 937 fail: 938 filemap_invalidate_unlock(inode->i_mapping); 939 inode_unlock(inode); 940 return error; 941 } 942 943 static int blkdev_mmap_prepare(struct vm_area_desc *desc) 944 { 945 struct file *file = desc->file; 946 947 if (bdev_read_only(I_BDEV(bdev_file_inode(file)))) 948 return generic_file_readonly_mmap_prepare(desc); 949 950 return generic_file_mmap_prepare(desc); 951 } 952 953 const struct file_operations def_blk_fops = { 954 .open = blkdev_open, 955 .release = blkdev_release, 956 .llseek = blkdev_llseek, 957 .read_iter = blkdev_read_iter, 958 .write_iter = blkdev_write_iter, 959 .iopoll = iocb_bio_iopoll, 960 .mmap_prepare = blkdev_mmap_prepare, 961 .fsync = blkdev_fsync, 962 .unlocked_ioctl = blkdev_ioctl, 963 #ifdef CONFIG_COMPAT 964 .compat_ioctl = compat_blkdev_ioctl, 965 #endif 966 .splice_read = filemap_splice_read, 967 .splice_write = iter_file_splice_write, 968 .fallocate = blkdev_fallocate, 969 .uring_cmd = blkdev_uring_cmd, 970 .fop_flags = FOP_BUFFER_RASYNC, 971 }; 972 973 static __init int blkdev_init(void) 974 { 975 return bioset_init(&blkdev_dio_pool, 4, 976 offsetof(struct blkdev_dio, bio), 977 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 978 } 979 module_init(blkdev_init); 980