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_invalid(struct block_device *bdev, loff_t pos, 38 struct iov_iter *iter, bool is_atomic) 39 { 40 if (is_atomic && !generic_atomic_write_valid(iter, pos)) 41 return true; 42 43 return pos & (bdev_logical_block_size(bdev) - 1) || 44 !bdev_iter_is_aligned(bdev, iter); 45 } 46 47 #define DIO_INLINE_BIO_VECS 4 48 49 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, 50 struct iov_iter *iter, struct block_device *bdev, 51 unsigned int nr_pages) 52 { 53 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; 54 loff_t pos = iocb->ki_pos; 55 bool should_dirty = false; 56 struct bio bio; 57 ssize_t ret; 58 59 if (nr_pages <= DIO_INLINE_BIO_VECS) 60 vecs = inline_vecs; 61 else { 62 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec), 63 GFP_KERNEL); 64 if (!vecs) 65 return -ENOMEM; 66 } 67 68 if (iov_iter_rw(iter) == READ) { 69 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ); 70 if (user_backed_iter(iter)) 71 should_dirty = true; 72 } else { 73 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb)); 74 } 75 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 76 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 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; 129 130 if (bio->bi_status && !dio->bio.bi_status) 131 dio->bio.bi_status = bio->bi_status; 132 133 if (atomic_dec_and_test(&dio->ref)) { 134 if (!(dio->flags & DIO_IS_SYNC)) { 135 struct kiocb *iocb = dio->iocb; 136 ssize_t ret; 137 138 WRITE_ONCE(iocb->private, NULL); 139 140 if (likely(!dio->bio.bi_status)) { 141 ret = dio->size; 142 iocb->ki_pos += ret; 143 } else { 144 ret = blk_status_to_errno(dio->bio.bi_status); 145 } 146 147 dio->iocb->ki_complete(iocb, ret); 148 bio_put(&dio->bio); 149 } else { 150 struct task_struct *waiter = dio->waiter; 151 152 WRITE_ONCE(dio->waiter, NULL); 153 blk_wake_io_task(waiter); 154 } 155 } 156 157 if (should_dirty) { 158 bio_check_pages_dirty(bio); 159 } else { 160 bio_release_pages(bio, false); 161 bio_put(bio); 162 } 163 } 164 165 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 166 struct block_device *bdev, unsigned int nr_pages) 167 { 168 struct blk_plug plug; 169 struct blkdev_dio *dio; 170 struct bio *bio; 171 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 172 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 173 loff_t pos = iocb->ki_pos; 174 int ret = 0; 175 176 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 177 opf |= REQ_ALLOC_CACHE; 178 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 179 &blkdev_dio_pool); 180 dio = container_of(bio, struct blkdev_dio, bio); 181 atomic_set(&dio->ref, 1); 182 /* 183 * Grab an extra reference to ensure the dio structure which is embedded 184 * into the first bio stays around. 185 */ 186 bio_get(bio); 187 188 is_sync = is_sync_kiocb(iocb); 189 if (is_sync) { 190 dio->flags = DIO_IS_SYNC; 191 dio->waiter = current; 192 } else { 193 dio->flags = 0; 194 dio->iocb = iocb; 195 } 196 197 dio->size = 0; 198 if (is_read && user_backed_iter(iter)) 199 dio->flags |= DIO_SHOULD_DIRTY; 200 201 blk_start_plug(&plug); 202 203 for (;;) { 204 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 205 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 206 bio->bi_private = dio; 207 bio->bi_end_io = blkdev_bio_end_io; 208 bio->bi_ioprio = iocb->ki_ioprio; 209 210 ret = bio_iov_iter_get_pages(bio, iter); 211 if (unlikely(ret)) { 212 bio->bi_status = BLK_STS_IOERR; 213 bio_endio(bio); 214 break; 215 } 216 if (iocb->ki_flags & IOCB_NOWAIT) { 217 /* 218 * This is nonblocking IO, and we need to allocate 219 * another bio if we have data left to map. As we 220 * cannot guarantee that one of the sub bios will not 221 * fail getting issued FOR NOWAIT and as error results 222 * are coalesced across all of them, be safe and ask for 223 * a retry of this from blocking context. 224 */ 225 if (unlikely(iov_iter_count(iter))) { 226 bio_release_pages(bio, false); 227 bio_clear_flag(bio, BIO_REFFED); 228 bio_put(bio); 229 blk_finish_plug(&plug); 230 return -EAGAIN; 231 } 232 bio->bi_opf |= REQ_NOWAIT; 233 } 234 235 if (is_read) { 236 if (dio->flags & DIO_SHOULD_DIRTY) 237 bio_set_pages_dirty(bio); 238 } else { 239 task_io_account_write(bio->bi_iter.bi_size); 240 } 241 dio->size += bio->bi_iter.bi_size; 242 pos += bio->bi_iter.bi_size; 243 244 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 245 if (!nr_pages) { 246 submit_bio(bio); 247 break; 248 } 249 atomic_inc(&dio->ref); 250 submit_bio(bio); 251 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 252 } 253 254 blk_finish_plug(&plug); 255 256 if (!is_sync) 257 return -EIOCBQUEUED; 258 259 for (;;) { 260 set_current_state(TASK_UNINTERRUPTIBLE); 261 if (!READ_ONCE(dio->waiter)) 262 break; 263 blk_io_schedule(); 264 } 265 __set_current_state(TASK_RUNNING); 266 267 if (!ret) 268 ret = blk_status_to_errno(dio->bio.bi_status); 269 if (likely(!ret)) 270 ret = dio->size; 271 272 bio_put(&dio->bio); 273 return ret; 274 } 275 276 static void blkdev_bio_end_io_async(struct bio *bio) 277 { 278 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 279 struct kiocb *iocb = dio->iocb; 280 ssize_t ret; 281 282 WRITE_ONCE(iocb->private, NULL); 283 284 if (likely(!bio->bi_status)) { 285 ret = dio->size; 286 iocb->ki_pos += ret; 287 } else { 288 ret = blk_status_to_errno(bio->bi_status); 289 } 290 291 iocb->ki_complete(iocb, ret); 292 293 if (dio->flags & DIO_SHOULD_DIRTY) { 294 bio_check_pages_dirty(bio); 295 } else { 296 bio_release_pages(bio, false); 297 bio_put(bio); 298 } 299 } 300 301 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 302 struct iov_iter *iter, 303 struct block_device *bdev, 304 unsigned int nr_pages) 305 { 306 bool is_read = iov_iter_rw(iter) == READ; 307 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 308 struct blkdev_dio *dio; 309 struct bio *bio; 310 loff_t pos = iocb->ki_pos; 311 int ret = 0; 312 313 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 314 opf |= REQ_ALLOC_CACHE; 315 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 316 &blkdev_dio_pool); 317 dio = container_of(bio, struct blkdev_dio, bio); 318 dio->flags = 0; 319 dio->iocb = iocb; 320 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 321 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 322 bio->bi_end_io = blkdev_bio_end_io_async; 323 bio->bi_ioprio = iocb->ki_ioprio; 324 325 if (iov_iter_is_bvec(iter)) { 326 /* 327 * Users don't rely on the iterator being in any particular 328 * state for async I/O returning -EIOCBQUEUED, hence we can 329 * avoid expensive iov_iter_advance(). Bypass 330 * bio_iov_iter_get_pages() and set the bvec directly. 331 */ 332 bio_iov_bvec_set(bio, iter); 333 } else { 334 ret = bio_iov_iter_get_pages(bio, iter); 335 if (unlikely(ret)) { 336 bio_put(bio); 337 return ret; 338 } 339 } 340 dio->size = bio->bi_iter.bi_size; 341 342 if (is_read) { 343 if (user_backed_iter(iter)) { 344 dio->flags |= DIO_SHOULD_DIRTY; 345 bio_set_pages_dirty(bio); 346 } 347 } else { 348 task_io_account_write(bio->bi_iter.bi_size); 349 } 350 351 if (iocb->ki_flags & IOCB_ATOMIC) 352 bio->bi_opf |= REQ_ATOMIC; 353 354 if (iocb->ki_flags & IOCB_NOWAIT) 355 bio->bi_opf |= REQ_NOWAIT; 356 357 if (iocb->ki_flags & IOCB_HIPRI) { 358 bio->bi_opf |= REQ_POLLED; 359 submit_bio(bio); 360 WRITE_ONCE(iocb->private, bio); 361 } else { 362 submit_bio(bio); 363 } 364 return -EIOCBQUEUED; 365 } 366 367 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 368 { 369 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 370 bool is_atomic = iocb->ki_flags & IOCB_ATOMIC; 371 unsigned int nr_pages; 372 373 if (!iov_iter_count(iter)) 374 return 0; 375 376 if (blkdev_dio_invalid(bdev, iocb->ki_pos, iter, is_atomic)) 377 return -EINVAL; 378 379 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 380 if (likely(nr_pages <= BIO_MAX_VECS)) { 381 if (is_sync_kiocb(iocb)) 382 return __blkdev_direct_IO_simple(iocb, iter, bdev, 383 nr_pages); 384 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages); 385 } else if (is_atomic) { 386 return -EINVAL; 387 } 388 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages)); 389 } 390 391 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 392 unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 393 { 394 struct block_device *bdev = I_BDEV(inode); 395 loff_t isize = i_size_read(inode); 396 397 if (offset >= isize) 398 return -EIO; 399 400 iomap->bdev = bdev; 401 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev)); 402 iomap->type = IOMAP_MAPPED; 403 iomap->addr = iomap->offset; 404 iomap->length = isize - iomap->offset; 405 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ 406 return 0; 407 } 408 409 static const struct iomap_ops blkdev_iomap_ops = { 410 .iomap_begin = blkdev_iomap_begin, 411 }; 412 413 #ifdef CONFIG_BUFFER_HEAD 414 static int blkdev_get_block(struct inode *inode, sector_t iblock, 415 struct buffer_head *bh, int create) 416 { 417 bh->b_bdev = I_BDEV(inode); 418 bh->b_blocknr = iblock; 419 set_buffer_mapped(bh); 420 return 0; 421 } 422 423 /* 424 * We cannot call mpage_writepages() as it does not take the buffer lock. 425 * We must use block_write_full_folio() directly which holds the buffer 426 * lock. The buffer lock provides the synchronisation with writeback 427 * that filesystems rely on when they use the blockdev's mapping. 428 */ 429 static int blkdev_writepages(struct address_space *mapping, 430 struct writeback_control *wbc) 431 { 432 struct blk_plug plug; 433 int err; 434 435 blk_start_plug(&plug); 436 err = write_cache_pages(mapping, wbc, block_write_full_folio, 437 blkdev_get_block); 438 blk_finish_plug(&plug); 439 440 return err; 441 } 442 443 static int blkdev_read_folio(struct file *file, struct folio *folio) 444 { 445 return block_read_full_folio(folio, blkdev_get_block); 446 } 447 448 static void blkdev_readahead(struct readahead_control *rac) 449 { 450 mpage_readahead(rac, blkdev_get_block); 451 } 452 453 static int blkdev_write_begin(struct file *file, struct address_space *mapping, 454 loff_t pos, unsigned len, struct page **pagep, void **fsdata) 455 { 456 return block_write_begin(mapping, pos, len, pagep, blkdev_get_block); 457 } 458 459 static int blkdev_write_end(struct file *file, struct address_space *mapping, 460 loff_t pos, unsigned len, unsigned copied, struct page *page, 461 void *fsdata) 462 { 463 int ret; 464 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); 465 466 unlock_page(page); 467 put_page(page); 468 469 return ret; 470 } 471 472 const struct address_space_operations def_blk_aops = { 473 .dirty_folio = block_dirty_folio, 474 .invalidate_folio = block_invalidate_folio, 475 .read_folio = blkdev_read_folio, 476 .readahead = blkdev_readahead, 477 .writepages = blkdev_writepages, 478 .write_begin = blkdev_write_begin, 479 .write_end = blkdev_write_end, 480 .migrate_folio = buffer_migrate_folio_norefs, 481 .is_dirty_writeback = buffer_check_dirty_writeback, 482 }; 483 #else /* CONFIG_BUFFER_HEAD */ 484 static int blkdev_read_folio(struct file *file, struct folio *folio) 485 { 486 return iomap_read_folio(folio, &blkdev_iomap_ops); 487 } 488 489 static void blkdev_readahead(struct readahead_control *rac) 490 { 491 iomap_readahead(rac, &blkdev_iomap_ops); 492 } 493 494 static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc, 495 struct inode *inode, loff_t offset, unsigned int len) 496 { 497 loff_t isize = i_size_read(inode); 498 499 if (WARN_ON_ONCE(offset >= isize)) 500 return -EIO; 501 if (offset >= wpc->iomap.offset && 502 offset < wpc->iomap.offset + wpc->iomap.length) 503 return 0; 504 return blkdev_iomap_begin(inode, offset, isize - offset, 505 IOMAP_WRITE, &wpc->iomap, NULL); 506 } 507 508 static const struct iomap_writeback_ops blkdev_writeback_ops = { 509 .map_blocks = blkdev_map_blocks, 510 }; 511 512 static int blkdev_writepages(struct address_space *mapping, 513 struct writeback_control *wbc) 514 { 515 struct iomap_writepage_ctx wpc = { }; 516 517 return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops); 518 } 519 520 const struct address_space_operations def_blk_aops = { 521 .dirty_folio = filemap_dirty_folio, 522 .release_folio = iomap_release_folio, 523 .invalidate_folio = iomap_invalidate_folio, 524 .read_folio = blkdev_read_folio, 525 .readahead = blkdev_readahead, 526 .writepages = blkdev_writepages, 527 .is_partially_uptodate = iomap_is_partially_uptodate, 528 .error_remove_folio = generic_error_remove_folio, 529 .migrate_folio = filemap_migrate_folio, 530 }; 531 #endif /* CONFIG_BUFFER_HEAD */ 532 533 /* 534 * for a block special file file_inode(file)->i_size is zero 535 * so we compute the size by hand (just as in block_read/write above) 536 */ 537 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 538 { 539 struct inode *bd_inode = bdev_file_inode(file); 540 loff_t retval; 541 542 inode_lock(bd_inode); 543 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 544 inode_unlock(bd_inode); 545 return retval; 546 } 547 548 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 549 int datasync) 550 { 551 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 552 int error; 553 554 error = file_write_and_wait_range(filp, start, end); 555 if (error) 556 return error; 557 558 /* 559 * There is no need to serialise calls to blkdev_issue_flush with 560 * i_mutex and doing so causes performance issues with concurrent 561 * O_SYNC writers to a block device. 562 */ 563 error = blkdev_issue_flush(bdev); 564 if (error == -EOPNOTSUPP) 565 error = 0; 566 567 return error; 568 } 569 570 /** 571 * file_to_blk_mode - get block open flags from file flags 572 * @file: file whose open flags should be converted 573 * 574 * Look at file open flags and generate corresponding block open flags from 575 * them. The function works both for file just being open (e.g. during ->open 576 * callback) and for file that is already open. This is actually non-trivial 577 * (see comment in the function). 578 */ 579 blk_mode_t file_to_blk_mode(struct file *file) 580 { 581 blk_mode_t mode = 0; 582 583 if (file->f_mode & FMODE_READ) 584 mode |= BLK_OPEN_READ; 585 if (file->f_mode & FMODE_WRITE) 586 mode |= BLK_OPEN_WRITE; 587 /* 588 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data 589 * to determine whether the open was exclusive for already open files. 590 */ 591 if (file->private_data) 592 mode |= BLK_OPEN_EXCL; 593 else if (file->f_flags & O_EXCL) 594 mode |= BLK_OPEN_EXCL; 595 if (file->f_flags & O_NDELAY) 596 mode |= BLK_OPEN_NDELAY; 597 598 /* 599 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 600 * driver has historically allowed ioctls as if the file was opened for 601 * writing, but does not allow and actual reads or writes. 602 */ 603 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 604 mode |= BLK_OPEN_WRITE_IOCTL; 605 606 return mode; 607 } 608 609 static int blkdev_open(struct inode *inode, struct file *filp) 610 { 611 struct block_device *bdev; 612 blk_mode_t mode; 613 int ret; 614 615 mode = file_to_blk_mode(filp); 616 /* Use the file as the holder. */ 617 if (mode & BLK_OPEN_EXCL) 618 filp->private_data = filp; 619 ret = bdev_permission(inode->i_rdev, mode, filp->private_data); 620 if (ret) 621 return ret; 622 623 bdev = blkdev_get_no_open(inode->i_rdev); 624 if (!bdev) 625 return -ENXIO; 626 627 if (bdev_can_atomic_write(bdev) && filp->f_flags & O_DIRECT) 628 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE; 629 630 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp); 631 if (ret) 632 blkdev_put_no_open(bdev); 633 return ret; 634 } 635 636 static int blkdev_release(struct inode *inode, struct file *filp) 637 { 638 bdev_release(filp); 639 return 0; 640 } 641 642 static ssize_t 643 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from) 644 { 645 size_t count = iov_iter_count(from); 646 ssize_t written; 647 648 written = kiocb_invalidate_pages(iocb, count); 649 if (written) { 650 if (written == -EBUSY) 651 return 0; 652 return written; 653 } 654 655 written = blkdev_direct_IO(iocb, from); 656 if (written > 0) { 657 kiocb_invalidate_post_direct_write(iocb, count); 658 iocb->ki_pos += written; 659 count -= written; 660 } 661 if (written != -EIOCBQUEUED) 662 iov_iter_revert(from, count - iov_iter_count(from)); 663 return written; 664 } 665 666 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from) 667 { 668 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops); 669 } 670 671 /* 672 * Write data to the block device. Only intended for the block device itself 673 * and the raw driver which basically is a fake block device. 674 * 675 * Does not take i_mutex for the write and thus is not for general purpose 676 * use. 677 */ 678 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 679 { 680 struct file *file = iocb->ki_filp; 681 struct inode *bd_inode = bdev_file_inode(file); 682 struct block_device *bdev = I_BDEV(bd_inode); 683 loff_t size = bdev_nr_bytes(bdev); 684 size_t shorted = 0; 685 ssize_t ret; 686 687 if (bdev_read_only(bdev)) 688 return -EPERM; 689 690 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 691 return -ETXTBSY; 692 693 if (!iov_iter_count(from)) 694 return 0; 695 696 if (iocb->ki_pos >= size) 697 return -ENOSPC; 698 699 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 700 return -EOPNOTSUPP; 701 702 size -= iocb->ki_pos; 703 if (iov_iter_count(from) > size) { 704 shorted = iov_iter_count(from) - size; 705 iov_iter_truncate(from, size); 706 } 707 708 ret = file_update_time(file); 709 if (ret) 710 return ret; 711 712 if (iocb->ki_flags & IOCB_DIRECT) { 713 ret = blkdev_direct_write(iocb, from); 714 if (ret >= 0 && iov_iter_count(from)) 715 ret = direct_write_fallback(iocb, from, ret, 716 blkdev_buffered_write(iocb, from)); 717 } else { 718 ret = blkdev_buffered_write(iocb, from); 719 } 720 721 if (ret > 0) 722 ret = generic_write_sync(iocb, ret); 723 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 724 return ret; 725 } 726 727 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 728 { 729 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 730 loff_t size = bdev_nr_bytes(bdev); 731 loff_t pos = iocb->ki_pos; 732 size_t shorted = 0; 733 ssize_t ret = 0; 734 size_t count; 735 736 if (unlikely(pos + iov_iter_count(to) > size)) { 737 if (pos >= size) 738 return 0; 739 size -= pos; 740 shorted = iov_iter_count(to) - size; 741 iov_iter_truncate(to, size); 742 } 743 744 count = iov_iter_count(to); 745 if (!count) 746 goto reexpand; /* skip atime */ 747 748 if (iocb->ki_flags & IOCB_DIRECT) { 749 ret = kiocb_write_and_wait(iocb, count); 750 if (ret < 0) 751 goto reexpand; 752 file_accessed(iocb->ki_filp); 753 754 ret = blkdev_direct_IO(iocb, to); 755 if (ret >= 0) { 756 iocb->ki_pos += ret; 757 count -= ret; 758 } 759 iov_iter_revert(to, count - iov_iter_count(to)); 760 if (ret < 0 || !count) 761 goto reexpand; 762 } 763 764 ret = filemap_read(iocb, to, ret); 765 766 reexpand: 767 if (unlikely(shorted)) 768 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 769 return ret; 770 } 771 772 #define BLKDEV_FALLOC_FL_SUPPORTED \ 773 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 774 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) 775 776 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 777 loff_t len) 778 { 779 struct inode *inode = bdev_file_inode(file); 780 struct block_device *bdev = I_BDEV(inode); 781 loff_t end = start + len - 1; 782 loff_t isize; 783 int error; 784 785 /* Fail if we don't recognize the flags. */ 786 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 787 return -EOPNOTSUPP; 788 789 /* Don't go off the end of the device. */ 790 isize = bdev_nr_bytes(bdev); 791 if (start >= isize) 792 return -EINVAL; 793 if (end >= isize) { 794 if (mode & FALLOC_FL_KEEP_SIZE) { 795 len = isize - start; 796 end = start + len - 1; 797 } else 798 return -EINVAL; 799 } 800 801 /* 802 * Don't allow IO that isn't aligned to logical block size. 803 */ 804 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 805 return -EINVAL; 806 807 filemap_invalidate_lock(inode->i_mapping); 808 809 /* 810 * Invalidate the page cache, including dirty pages, for valid 811 * de-allocate mode calls to fallocate(). 812 */ 813 switch (mode) { 814 case FALLOC_FL_ZERO_RANGE: 815 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 816 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 817 if (error) 818 goto fail; 819 820 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 821 len >> SECTOR_SHIFT, GFP_KERNEL, 822 BLKDEV_ZERO_NOUNMAP); 823 break; 824 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 825 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 826 if (error) 827 goto fail; 828 829 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 830 len >> SECTOR_SHIFT, GFP_KERNEL, 831 BLKDEV_ZERO_NOFALLBACK); 832 break; 833 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: 834 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 835 if (error) 836 goto fail; 837 838 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, 839 len >> SECTOR_SHIFT, GFP_KERNEL); 840 break; 841 default: 842 error = -EOPNOTSUPP; 843 } 844 845 fail: 846 filemap_invalidate_unlock(inode->i_mapping); 847 return error; 848 } 849 850 static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) 851 { 852 struct inode *bd_inode = bdev_file_inode(file); 853 854 if (bdev_read_only(I_BDEV(bd_inode))) 855 return generic_file_readonly_mmap(file, vma); 856 857 return generic_file_mmap(file, vma); 858 } 859 860 const struct file_operations def_blk_fops = { 861 .open = blkdev_open, 862 .release = blkdev_release, 863 .llseek = blkdev_llseek, 864 .read_iter = blkdev_read_iter, 865 .write_iter = blkdev_write_iter, 866 .iopoll = iocb_bio_iopoll, 867 .mmap = blkdev_mmap, 868 .fsync = blkdev_fsync, 869 .unlocked_ioctl = blkdev_ioctl, 870 #ifdef CONFIG_COMPAT 871 .compat_ioctl = compat_blkdev_ioctl, 872 #endif 873 .splice_read = filemap_splice_read, 874 .splice_write = iter_file_splice_write, 875 .fallocate = blkdev_fallocate, 876 .fop_flags = FOP_BUFFER_RASYNC, 877 }; 878 879 static __init int blkdev_init(void) 880 { 881 return bioset_init(&blkdev_dio_pool, 4, 882 offsetof(struct blkdev_dio, bio), 883 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 884 } 885 module_init(blkdev_init); 886