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/iomap.h> 19 #include <linux/module.h> 20 #include <linux/io_uring/cmd.h> 21 #include "blk.h" 22 23 static inline struct inode *bdev_file_inode(struct file *file) 24 { 25 return file->f_mapping->host; 26 } 27 28 static blk_opf_t dio_bio_write_op(struct kiocb *iocb) 29 { 30 blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; 31 32 /* avoid the need for a I/O completion work item */ 33 if (iocb_is_dsync(iocb)) 34 opf |= REQ_FUA; 35 return opf; 36 } 37 38 static bool blkdev_dio_invalid(struct block_device *bdev, struct kiocb *iocb, 39 struct iov_iter *iter) 40 { 41 return iocb->ki_pos & (bdev_logical_block_size(bdev) - 1) || 42 !bdev_iter_is_aligned(bdev, iter); 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, struct block_device *bdev, 49 unsigned int nr_pages) 50 { 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 WARN_ON_ONCE(iocb->ki_flags & IOCB_HAS_METADATA); 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 (!is_sync && (dio->iocb->ki_flags & IOCB_HAS_METADATA)) 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 (!is_sync && (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 (iocb->ki_flags & IOCB_HAS_METADATA) 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 if (is_sync_kiocb(iocb)) 427 return __blkdev_direct_IO_simple(iocb, iter, bdev, 428 nr_pages); 429 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages); 430 } else if (iocb->ki_flags & IOCB_ATOMIC) { 431 return -EINVAL; 432 } 433 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages)); 434 } 435 436 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 437 unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 438 { 439 struct block_device *bdev = I_BDEV(inode); 440 loff_t isize = i_size_read(inode); 441 442 if (offset >= isize) 443 return -EIO; 444 445 iomap->bdev = bdev; 446 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev)); 447 iomap->type = IOMAP_MAPPED; 448 iomap->addr = iomap->offset; 449 iomap->length = isize - iomap->offset; 450 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ 451 return 0; 452 } 453 454 static const struct iomap_ops blkdev_iomap_ops = { 455 .iomap_begin = blkdev_iomap_begin, 456 }; 457 458 #ifdef CONFIG_BUFFER_HEAD 459 static int blkdev_get_block(struct inode *inode, sector_t iblock, 460 struct buffer_head *bh, int create) 461 { 462 bh->b_bdev = I_BDEV(inode); 463 bh->b_blocknr = iblock; 464 set_buffer_mapped(bh); 465 return 0; 466 } 467 468 /* 469 * We cannot call mpage_writepages() as it does not take the buffer lock. 470 * We must use block_write_full_folio() directly which holds the buffer 471 * lock. The buffer lock provides the synchronisation with writeback 472 * that filesystems rely on when they use the blockdev's mapping. 473 */ 474 static int blkdev_writepages(struct address_space *mapping, 475 struct writeback_control *wbc) 476 { 477 struct folio *folio = NULL; 478 struct blk_plug plug; 479 int err; 480 481 blk_start_plug(&plug); 482 while ((folio = writeback_iter(mapping, wbc, folio, &err))) 483 err = block_write_full_folio(folio, wbc, blkdev_get_block); 484 blk_finish_plug(&plug); 485 486 return err; 487 } 488 489 static int blkdev_read_folio(struct file *file, struct folio *folio) 490 { 491 return block_read_full_folio(folio, blkdev_get_block); 492 } 493 494 static void blkdev_readahead(struct readahead_control *rac) 495 { 496 mpage_readahead(rac, blkdev_get_block); 497 } 498 499 static int blkdev_write_begin(struct file *file, struct address_space *mapping, 500 loff_t pos, unsigned len, struct folio **foliop, void **fsdata) 501 { 502 return block_write_begin(mapping, pos, len, foliop, blkdev_get_block); 503 } 504 505 static int blkdev_write_end(struct file *file, struct address_space *mapping, 506 loff_t pos, unsigned len, unsigned copied, struct folio *folio, 507 void *fsdata) 508 { 509 int ret; 510 ret = block_write_end(file, mapping, pos, len, copied, folio, fsdata); 511 512 folio_unlock(folio); 513 folio_put(folio); 514 515 return ret; 516 } 517 518 const struct address_space_operations def_blk_aops = { 519 .dirty_folio = block_dirty_folio, 520 .invalidate_folio = block_invalidate_folio, 521 .read_folio = blkdev_read_folio, 522 .readahead = blkdev_readahead, 523 .writepages = blkdev_writepages, 524 .write_begin = blkdev_write_begin, 525 .write_end = blkdev_write_end, 526 .migrate_folio = buffer_migrate_folio_norefs, 527 .is_dirty_writeback = buffer_check_dirty_writeback, 528 }; 529 #else /* CONFIG_BUFFER_HEAD */ 530 static int blkdev_read_folio(struct file *file, struct folio *folio) 531 { 532 return iomap_read_folio(folio, &blkdev_iomap_ops); 533 } 534 535 static void blkdev_readahead(struct readahead_control *rac) 536 { 537 iomap_readahead(rac, &blkdev_iomap_ops); 538 } 539 540 static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc, 541 struct inode *inode, loff_t offset, unsigned int len) 542 { 543 loff_t isize = i_size_read(inode); 544 545 if (WARN_ON_ONCE(offset >= isize)) 546 return -EIO; 547 if (offset >= wpc->iomap.offset && 548 offset < wpc->iomap.offset + wpc->iomap.length) 549 return 0; 550 return blkdev_iomap_begin(inode, offset, isize - offset, 551 IOMAP_WRITE, &wpc->iomap, NULL); 552 } 553 554 static const struct iomap_writeback_ops blkdev_writeback_ops = { 555 .map_blocks = blkdev_map_blocks, 556 }; 557 558 static int blkdev_writepages(struct address_space *mapping, 559 struct writeback_control *wbc) 560 { 561 struct iomap_writepage_ctx wpc = { }; 562 563 return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops); 564 } 565 566 const struct address_space_operations def_blk_aops = { 567 .dirty_folio = filemap_dirty_folio, 568 .release_folio = iomap_release_folio, 569 .invalidate_folio = iomap_invalidate_folio, 570 .read_folio = blkdev_read_folio, 571 .readahead = blkdev_readahead, 572 .writepages = blkdev_writepages, 573 .is_partially_uptodate = iomap_is_partially_uptodate, 574 .error_remove_folio = generic_error_remove_folio, 575 .migrate_folio = filemap_migrate_folio, 576 }; 577 #endif /* CONFIG_BUFFER_HEAD */ 578 579 /* 580 * for a block special file file_inode(file)->i_size is zero 581 * so we compute the size by hand (just as in block_read/write above) 582 */ 583 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 584 { 585 struct inode *bd_inode = bdev_file_inode(file); 586 loff_t retval; 587 588 inode_lock(bd_inode); 589 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 590 inode_unlock(bd_inode); 591 return retval; 592 } 593 594 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 595 int datasync) 596 { 597 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 598 int error; 599 600 error = file_write_and_wait_range(filp, start, end); 601 if (error) 602 return error; 603 604 /* 605 * There is no need to serialise calls to blkdev_issue_flush with 606 * i_mutex and doing so causes performance issues with concurrent 607 * O_SYNC writers to a block device. 608 */ 609 error = blkdev_issue_flush(bdev); 610 if (error == -EOPNOTSUPP) 611 error = 0; 612 613 return error; 614 } 615 616 /** 617 * file_to_blk_mode - get block open flags from file flags 618 * @file: file whose open flags should be converted 619 * 620 * Look at file open flags and generate corresponding block open flags from 621 * them. The function works both for file just being open (e.g. during ->open 622 * callback) and for file that is already open. This is actually non-trivial 623 * (see comment in the function). 624 */ 625 blk_mode_t file_to_blk_mode(struct file *file) 626 { 627 blk_mode_t mode = 0; 628 629 if (file->f_mode & FMODE_READ) 630 mode |= BLK_OPEN_READ; 631 if (file->f_mode & FMODE_WRITE) 632 mode |= BLK_OPEN_WRITE; 633 /* 634 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data 635 * to determine whether the open was exclusive for already open files. 636 */ 637 if (file->private_data) 638 mode |= BLK_OPEN_EXCL; 639 else if (file->f_flags & O_EXCL) 640 mode |= BLK_OPEN_EXCL; 641 if (file->f_flags & O_NDELAY) 642 mode |= BLK_OPEN_NDELAY; 643 644 /* 645 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 646 * driver has historically allowed ioctls as if the file was opened for 647 * writing, but does not allow and actual reads or writes. 648 */ 649 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 650 mode |= BLK_OPEN_WRITE_IOCTL; 651 652 return mode; 653 } 654 655 static int blkdev_open(struct inode *inode, struct file *filp) 656 { 657 struct block_device *bdev; 658 blk_mode_t mode; 659 int ret; 660 661 mode = file_to_blk_mode(filp); 662 /* Use the file as the holder. */ 663 if (mode & BLK_OPEN_EXCL) 664 filp->private_data = filp; 665 ret = bdev_permission(inode->i_rdev, mode, filp->private_data); 666 if (ret) 667 return ret; 668 669 bdev = blkdev_get_no_open(inode->i_rdev, true); 670 if (!bdev) 671 return -ENXIO; 672 673 if (bdev_can_atomic_write(bdev)) 674 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE; 675 676 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp); 677 if (ret) 678 blkdev_put_no_open(bdev); 679 return ret; 680 } 681 682 static int blkdev_release(struct inode *inode, struct file *filp) 683 { 684 bdev_release(filp); 685 return 0; 686 } 687 688 static ssize_t 689 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from) 690 { 691 size_t count = iov_iter_count(from); 692 ssize_t written; 693 694 written = kiocb_invalidate_pages(iocb, count); 695 if (written) { 696 if (written == -EBUSY) 697 return 0; 698 return written; 699 } 700 701 written = blkdev_direct_IO(iocb, from); 702 if (written > 0) { 703 kiocb_invalidate_post_direct_write(iocb, count); 704 iocb->ki_pos += written; 705 count -= written; 706 } 707 if (written != -EIOCBQUEUED) 708 iov_iter_revert(from, count - iov_iter_count(from)); 709 return written; 710 } 711 712 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from) 713 { 714 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL); 715 } 716 717 /* 718 * Write data to the block device. Only intended for the block device itself 719 * and the raw driver which basically is a fake block device. 720 * 721 * Does not take i_mutex for the write and thus is not for general purpose 722 * use. 723 */ 724 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 725 { 726 struct file *file = iocb->ki_filp; 727 struct inode *bd_inode = bdev_file_inode(file); 728 struct block_device *bdev = I_BDEV(bd_inode); 729 bool atomic = iocb->ki_flags & IOCB_ATOMIC; 730 loff_t size = bdev_nr_bytes(bdev); 731 size_t shorted = 0; 732 ssize_t ret; 733 734 if (bdev_read_only(bdev)) 735 return -EPERM; 736 737 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 738 return -ETXTBSY; 739 740 if (!iov_iter_count(from)) 741 return 0; 742 743 if (iocb->ki_pos >= size) 744 return -ENOSPC; 745 746 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 747 return -EOPNOTSUPP; 748 749 if (atomic) { 750 ret = generic_atomic_write_valid(iocb, from); 751 if (ret) 752 return ret; 753 } 754 755 size -= iocb->ki_pos; 756 if (iov_iter_count(from) > size) { 757 if (atomic) 758 return -EINVAL; 759 shorted = iov_iter_count(from) - size; 760 iov_iter_truncate(from, size); 761 } 762 763 ret = file_update_time(file); 764 if (ret) 765 return ret; 766 767 if (iocb->ki_flags & IOCB_DIRECT) { 768 ret = blkdev_direct_write(iocb, from); 769 if (ret >= 0 && iov_iter_count(from)) 770 ret = direct_write_fallback(iocb, from, ret, 771 blkdev_buffered_write(iocb, from)); 772 } else { 773 /* 774 * Take i_rwsem and invalidate_lock to avoid racing with 775 * set_blocksize changing i_blkbits/folio order and punching 776 * out the pagecache. 777 */ 778 inode_lock_shared(bd_inode); 779 ret = blkdev_buffered_write(iocb, from); 780 inode_unlock_shared(bd_inode); 781 } 782 783 if (ret > 0) 784 ret = generic_write_sync(iocb, ret); 785 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 786 return ret; 787 } 788 789 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 790 { 791 struct inode *bd_inode = bdev_file_inode(iocb->ki_filp); 792 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 793 loff_t size = bdev_nr_bytes(bdev); 794 loff_t pos = iocb->ki_pos; 795 size_t shorted = 0; 796 ssize_t ret = 0; 797 size_t count; 798 799 if (unlikely(pos + iov_iter_count(to) > size)) { 800 if (pos >= size) 801 return 0; 802 size -= pos; 803 shorted = iov_iter_count(to) - size; 804 iov_iter_truncate(to, size); 805 } 806 807 count = iov_iter_count(to); 808 if (!count) 809 goto reexpand; /* skip atime */ 810 811 if (iocb->ki_flags & IOCB_DIRECT) { 812 ret = kiocb_write_and_wait(iocb, count); 813 if (ret < 0) 814 goto reexpand; 815 file_accessed(iocb->ki_filp); 816 817 ret = blkdev_direct_IO(iocb, to); 818 if (ret > 0) { 819 iocb->ki_pos += ret; 820 count -= ret; 821 } 822 if (ret != -EIOCBQUEUED) 823 iov_iter_revert(to, count - iov_iter_count(to)); 824 if (ret < 0 || !count) 825 goto reexpand; 826 } 827 828 /* 829 * Take i_rwsem and invalidate_lock to avoid racing with set_blocksize 830 * changing i_blkbits/folio order and punching out the pagecache. 831 */ 832 inode_lock_shared(bd_inode); 833 ret = filemap_read(iocb, to, ret); 834 inode_unlock_shared(bd_inode); 835 836 reexpand: 837 if (unlikely(shorted)) 838 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 839 return ret; 840 } 841 842 #define BLKDEV_FALLOC_FL_SUPPORTED \ 843 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 844 FALLOC_FL_ZERO_RANGE) 845 846 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 847 loff_t len) 848 { 849 struct inode *inode = bdev_file_inode(file); 850 struct block_device *bdev = I_BDEV(inode); 851 loff_t end = start + len - 1; 852 loff_t isize; 853 int error; 854 855 /* Fail if we don't recognize the flags. */ 856 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 857 return -EOPNOTSUPP; 858 859 /* Don't go off the end of the device. */ 860 isize = bdev_nr_bytes(bdev); 861 if (start >= isize) 862 return -EINVAL; 863 if (end >= isize) { 864 if (mode & FALLOC_FL_KEEP_SIZE) { 865 len = isize - start; 866 end = start + len - 1; 867 } else 868 return -EINVAL; 869 } 870 871 /* 872 * Don't allow IO that isn't aligned to logical block size. 873 */ 874 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 875 return -EINVAL; 876 877 inode_lock(inode); 878 filemap_invalidate_lock(inode->i_mapping); 879 880 /* 881 * Invalidate the page cache, including dirty pages, for valid 882 * de-allocate mode calls to fallocate(). 883 */ 884 switch (mode) { 885 case FALLOC_FL_ZERO_RANGE: 886 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 887 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 888 if (error) 889 goto fail; 890 891 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 892 len >> SECTOR_SHIFT, GFP_KERNEL, 893 BLKDEV_ZERO_NOUNMAP); 894 break; 895 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 896 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 897 if (error) 898 goto fail; 899 900 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 901 len >> SECTOR_SHIFT, GFP_KERNEL, 902 BLKDEV_ZERO_NOFALLBACK); 903 break; 904 default: 905 error = -EOPNOTSUPP; 906 } 907 908 fail: 909 filemap_invalidate_unlock(inode->i_mapping); 910 inode_unlock(inode); 911 return error; 912 } 913 914 static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) 915 { 916 struct inode *bd_inode = bdev_file_inode(file); 917 918 if (bdev_read_only(I_BDEV(bd_inode))) 919 return generic_file_readonly_mmap(file, vma); 920 921 return generic_file_mmap(file, vma); 922 } 923 924 const struct file_operations def_blk_fops = { 925 .open = blkdev_open, 926 .release = blkdev_release, 927 .llseek = blkdev_llseek, 928 .read_iter = blkdev_read_iter, 929 .write_iter = blkdev_write_iter, 930 .iopoll = iocb_bio_iopoll, 931 .mmap = blkdev_mmap, 932 .fsync = blkdev_fsync, 933 .unlocked_ioctl = blkdev_ioctl, 934 #ifdef CONFIG_COMPAT 935 .compat_ioctl = compat_blkdev_ioctl, 936 #endif 937 .splice_read = filemap_splice_read, 938 .splice_write = iter_file_splice_write, 939 .fallocate = blkdev_fallocate, 940 .uring_cmd = blkdev_uring_cmd, 941 .fop_flags = FOP_BUFFER_RASYNC, 942 }; 943 944 static __init int blkdev_init(void) 945 { 946 return bioset_init(&blkdev_dio_pool, 4, 947 offsetof(struct blkdev_dio, bio), 948 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 949 } 950 module_init(blkdev_init); 951