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