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