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, unsigned int nr_pages) 48 { 49 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 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 (blkdev_dio_unaligned(bdev, pos, iter)) 57 return -EINVAL; 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_ioprio = iocb->ki_ioprio; 77 78 ret = bio_iov_iter_get_pages(&bio, iter); 79 if (unlikely(ret)) 80 goto out; 81 ret = bio.bi_iter.bi_size; 82 83 if (iov_iter_rw(iter) == WRITE) 84 task_io_account_write(ret); 85 86 if (iocb->ki_flags & IOCB_NOWAIT) 87 bio.bi_opf |= REQ_NOWAIT; 88 89 submit_bio_wait(&bio); 90 91 bio_release_pages(&bio, should_dirty); 92 if (unlikely(bio.bi_status)) 93 ret = blk_status_to_errno(bio.bi_status); 94 95 out: 96 if (vecs != inline_vecs) 97 kfree(vecs); 98 99 bio_uninit(&bio); 100 101 return ret; 102 } 103 104 enum { 105 DIO_SHOULD_DIRTY = 1, 106 DIO_IS_SYNC = 2, 107 }; 108 109 struct blkdev_dio { 110 union { 111 struct kiocb *iocb; 112 struct task_struct *waiter; 113 }; 114 size_t size; 115 atomic_t ref; 116 unsigned int flags; 117 struct bio bio ____cacheline_aligned_in_smp; 118 }; 119 120 static struct bio_set blkdev_dio_pool; 121 122 static void blkdev_bio_end_io(struct bio *bio) 123 { 124 struct blkdev_dio *dio = bio->bi_private; 125 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 126 127 if (bio->bi_status && !dio->bio.bi_status) 128 dio->bio.bi_status = bio->bi_status; 129 130 if (atomic_dec_and_test(&dio->ref)) { 131 if (!(dio->flags & DIO_IS_SYNC)) { 132 struct kiocb *iocb = dio->iocb; 133 ssize_t ret; 134 135 WRITE_ONCE(iocb->private, NULL); 136 137 if (likely(!dio->bio.bi_status)) { 138 ret = dio->size; 139 iocb->ki_pos += ret; 140 } else { 141 ret = blk_status_to_errno(dio->bio.bi_status); 142 } 143 144 dio->iocb->ki_complete(iocb, ret); 145 bio_put(&dio->bio); 146 } else { 147 struct task_struct *waiter = dio->waiter; 148 149 WRITE_ONCE(dio->waiter, NULL); 150 blk_wake_io_task(waiter); 151 } 152 } 153 154 if (should_dirty) { 155 bio_check_pages_dirty(bio); 156 } else { 157 bio_release_pages(bio, false); 158 bio_put(bio); 159 } 160 } 161 162 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 163 unsigned int nr_pages) 164 { 165 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 166 struct blk_plug plug; 167 struct blkdev_dio *dio; 168 struct bio *bio; 169 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 170 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 171 loff_t pos = iocb->ki_pos; 172 int ret = 0; 173 174 if (blkdev_dio_unaligned(bdev, pos, iter)) 175 return -EINVAL; 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_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 unsigned int nr_pages) 304 { 305 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 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 (blkdev_dio_unaligned(bdev, pos, iter)) 314 return -EINVAL; 315 316 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 317 opf |= REQ_ALLOC_CACHE; 318 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 319 &blkdev_dio_pool); 320 dio = container_of(bio, struct blkdev_dio, bio); 321 dio->flags = 0; 322 dio->iocb = iocb; 323 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 324 bio->bi_end_io = blkdev_bio_end_io_async; 325 bio->bi_ioprio = iocb->ki_ioprio; 326 327 if (iov_iter_is_bvec(iter)) { 328 /* 329 * Users don't rely on the iterator being in any particular 330 * state for async I/O returning -EIOCBQUEUED, hence we can 331 * avoid expensive iov_iter_advance(). Bypass 332 * bio_iov_iter_get_pages() and set the bvec directly. 333 */ 334 bio_iov_bvec_set(bio, iter); 335 } else { 336 ret = bio_iov_iter_get_pages(bio, iter); 337 if (unlikely(ret)) { 338 bio_put(bio); 339 return ret; 340 } 341 } 342 dio->size = bio->bi_iter.bi_size; 343 344 if (is_read) { 345 if (user_backed_iter(iter)) { 346 dio->flags |= DIO_SHOULD_DIRTY; 347 bio_set_pages_dirty(bio); 348 } 349 } else { 350 task_io_account_write(bio->bi_iter.bi_size); 351 } 352 353 if (iocb->ki_flags & IOCB_NOWAIT) 354 bio->bi_opf |= REQ_NOWAIT; 355 356 if (iocb->ki_flags & IOCB_HIPRI) { 357 bio->bi_opf |= REQ_POLLED; 358 submit_bio(bio); 359 WRITE_ONCE(iocb->private, bio); 360 } else { 361 submit_bio(bio); 362 } 363 return -EIOCBQUEUED; 364 } 365 366 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 367 { 368 unsigned int nr_pages; 369 370 if (!iov_iter_count(iter)) 371 return 0; 372 373 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 374 if (likely(nr_pages <= BIO_MAX_VECS)) { 375 if (is_sync_kiocb(iocb)) 376 return __blkdev_direct_IO_simple(iocb, iter, nr_pages); 377 return __blkdev_direct_IO_async(iocb, iter, nr_pages); 378 } 379 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages)); 380 } 381 382 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 383 unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 384 { 385 struct block_device *bdev = I_BDEV(inode); 386 loff_t isize = i_size_read(inode); 387 388 iomap->bdev = bdev; 389 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev)); 390 if (iomap->offset >= isize) 391 return -EIO; 392 iomap->type = IOMAP_MAPPED; 393 iomap->addr = iomap->offset; 394 iomap->length = isize - iomap->offset; 395 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ 396 return 0; 397 } 398 399 static const struct iomap_ops blkdev_iomap_ops = { 400 .iomap_begin = blkdev_iomap_begin, 401 }; 402 403 #ifdef CONFIG_BUFFER_HEAD 404 static int blkdev_get_block(struct inode *inode, sector_t iblock, 405 struct buffer_head *bh, int create) 406 { 407 bh->b_bdev = I_BDEV(inode); 408 bh->b_blocknr = iblock; 409 set_buffer_mapped(bh); 410 return 0; 411 } 412 413 static int blkdev_writepage(struct page *page, struct writeback_control *wbc) 414 { 415 return block_write_full_page(page, blkdev_get_block, wbc); 416 } 417 418 static int blkdev_read_folio(struct file *file, struct folio *folio) 419 { 420 return block_read_full_folio(folio, blkdev_get_block); 421 } 422 423 static void blkdev_readahead(struct readahead_control *rac) 424 { 425 mpage_readahead(rac, blkdev_get_block); 426 } 427 428 static int blkdev_write_begin(struct file *file, struct address_space *mapping, 429 loff_t pos, unsigned len, struct page **pagep, void **fsdata) 430 { 431 return block_write_begin(mapping, pos, len, pagep, blkdev_get_block); 432 } 433 434 static int blkdev_write_end(struct file *file, struct address_space *mapping, 435 loff_t pos, unsigned len, unsigned copied, struct page *page, 436 void *fsdata) 437 { 438 int ret; 439 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); 440 441 unlock_page(page); 442 put_page(page); 443 444 return ret; 445 } 446 447 const struct address_space_operations def_blk_aops = { 448 .dirty_folio = block_dirty_folio, 449 .invalidate_folio = block_invalidate_folio, 450 .read_folio = blkdev_read_folio, 451 .readahead = blkdev_readahead, 452 .writepage = blkdev_writepage, 453 .write_begin = blkdev_write_begin, 454 .write_end = blkdev_write_end, 455 .migrate_folio = buffer_migrate_folio_norefs, 456 .is_dirty_writeback = buffer_check_dirty_writeback, 457 }; 458 #else /* CONFIG_BUFFER_HEAD */ 459 static int blkdev_read_folio(struct file *file, struct folio *folio) 460 { 461 return iomap_read_folio(folio, &blkdev_iomap_ops); 462 } 463 464 static void blkdev_readahead(struct readahead_control *rac) 465 { 466 iomap_readahead(rac, &blkdev_iomap_ops); 467 } 468 469 static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc, 470 struct inode *inode, loff_t offset) 471 { 472 loff_t isize = i_size_read(inode); 473 474 if (WARN_ON_ONCE(offset >= isize)) 475 return -EIO; 476 if (offset >= wpc->iomap.offset && 477 offset < wpc->iomap.offset + wpc->iomap.length) 478 return 0; 479 return blkdev_iomap_begin(inode, offset, isize - offset, 480 IOMAP_WRITE, &wpc->iomap, NULL); 481 } 482 483 static const struct iomap_writeback_ops blkdev_writeback_ops = { 484 .map_blocks = blkdev_map_blocks, 485 }; 486 487 static int blkdev_writepages(struct address_space *mapping, 488 struct writeback_control *wbc) 489 { 490 struct iomap_writepage_ctx wpc = { }; 491 492 return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops); 493 } 494 495 const struct address_space_operations def_blk_aops = { 496 .dirty_folio = filemap_dirty_folio, 497 .release_folio = iomap_release_folio, 498 .invalidate_folio = iomap_invalidate_folio, 499 .read_folio = blkdev_read_folio, 500 .readahead = blkdev_readahead, 501 .writepages = blkdev_writepages, 502 .is_partially_uptodate = iomap_is_partially_uptodate, 503 .error_remove_page = generic_error_remove_page, 504 .migrate_folio = filemap_migrate_folio, 505 }; 506 #endif /* CONFIG_BUFFER_HEAD */ 507 508 /* 509 * for a block special file file_inode(file)->i_size is zero 510 * so we compute the size by hand (just as in block_read/write above) 511 */ 512 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 513 { 514 struct inode *bd_inode = bdev_file_inode(file); 515 loff_t retval; 516 517 inode_lock(bd_inode); 518 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 519 inode_unlock(bd_inode); 520 return retval; 521 } 522 523 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 524 int datasync) 525 { 526 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 527 int error; 528 529 error = file_write_and_wait_range(filp, start, end); 530 if (error) 531 return error; 532 533 /* 534 * There is no need to serialise calls to blkdev_issue_flush with 535 * i_mutex and doing so causes performance issues with concurrent 536 * O_SYNC writers to a block device. 537 */ 538 error = blkdev_issue_flush(bdev); 539 if (error == -EOPNOTSUPP) 540 error = 0; 541 542 return error; 543 } 544 545 blk_mode_t file_to_blk_mode(struct file *file) 546 { 547 blk_mode_t mode = 0; 548 549 if (file->f_mode & FMODE_READ) 550 mode |= BLK_OPEN_READ; 551 if (file->f_mode & FMODE_WRITE) 552 mode |= BLK_OPEN_WRITE; 553 if (file->private_data) 554 mode |= BLK_OPEN_EXCL; 555 if (file->f_flags & O_NDELAY) 556 mode |= BLK_OPEN_NDELAY; 557 558 /* 559 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 560 * driver has historically allowed ioctls as if the file was opened for 561 * writing, but does not allow and actual reads or writes. 562 */ 563 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 564 mode |= BLK_OPEN_WRITE_IOCTL; 565 566 return mode; 567 } 568 569 static int blkdev_open(struct inode *inode, struct file *filp) 570 { 571 struct block_device *bdev; 572 573 /* 574 * Preserve backwards compatibility and allow large file access 575 * even if userspace doesn't ask for it explicitly. Some mkfs 576 * binary needs it. We might want to drop this workaround 577 * during an unstable branch. 578 */ 579 filp->f_flags |= O_LARGEFILE; 580 filp->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT; 581 582 /* 583 * Use the file private data to store the holder for exclusive openes. 584 * file_to_blk_mode relies on it being present to set BLK_OPEN_EXCL. 585 */ 586 if (filp->f_flags & O_EXCL) 587 filp->private_data = filp; 588 589 bdev = blkdev_get_by_dev(inode->i_rdev, file_to_blk_mode(filp), 590 filp->private_data, NULL); 591 if (IS_ERR(bdev)) 592 return PTR_ERR(bdev); 593 594 if (bdev_nowait(bdev)) 595 filp->f_mode |= FMODE_NOWAIT; 596 597 filp->f_mapping = bdev->bd_inode->i_mapping; 598 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); 599 return 0; 600 } 601 602 static int blkdev_release(struct inode *inode, struct file *filp) 603 { 604 blkdev_put(I_BDEV(filp->f_mapping->host), filp->private_data); 605 return 0; 606 } 607 608 static ssize_t 609 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from) 610 { 611 size_t count = iov_iter_count(from); 612 ssize_t written; 613 614 written = kiocb_invalidate_pages(iocb, count); 615 if (written) { 616 if (written == -EBUSY) 617 return 0; 618 return written; 619 } 620 621 written = blkdev_direct_IO(iocb, from); 622 if (written > 0) { 623 kiocb_invalidate_post_direct_write(iocb, count); 624 iocb->ki_pos += written; 625 count -= written; 626 } 627 if (written != -EIOCBQUEUED) 628 iov_iter_revert(from, count - iov_iter_count(from)); 629 return written; 630 } 631 632 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from) 633 { 634 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops); 635 } 636 637 /* 638 * Write data to the block device. Only intended for the block device itself 639 * and the raw driver which basically is a fake block device. 640 * 641 * Does not take i_mutex for the write and thus is not for general purpose 642 * use. 643 */ 644 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 645 { 646 struct file *file = iocb->ki_filp; 647 struct block_device *bdev = I_BDEV(file->f_mapping->host); 648 struct inode *bd_inode = bdev->bd_inode; 649 loff_t size = bdev_nr_bytes(bdev); 650 size_t shorted = 0; 651 ssize_t ret; 652 653 if (bdev_read_only(bdev)) 654 return -EPERM; 655 656 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 657 return -ETXTBSY; 658 659 if (!iov_iter_count(from)) 660 return 0; 661 662 if (iocb->ki_pos >= size) 663 return -ENOSPC; 664 665 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 666 return -EOPNOTSUPP; 667 668 size -= iocb->ki_pos; 669 if (iov_iter_count(from) > size) { 670 shorted = iov_iter_count(from) - size; 671 iov_iter_truncate(from, size); 672 } 673 674 ret = file_update_time(file); 675 if (ret) 676 return ret; 677 678 if (iocb->ki_flags & IOCB_DIRECT) { 679 ret = blkdev_direct_write(iocb, from); 680 if (ret >= 0 && iov_iter_count(from)) 681 ret = direct_write_fallback(iocb, from, ret, 682 blkdev_buffered_write(iocb, from)); 683 } else { 684 ret = blkdev_buffered_write(iocb, from); 685 } 686 687 if (ret > 0) 688 ret = generic_write_sync(iocb, ret); 689 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 690 return ret; 691 } 692 693 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 694 { 695 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 696 loff_t size = bdev_nr_bytes(bdev); 697 loff_t pos = iocb->ki_pos; 698 size_t shorted = 0; 699 ssize_t ret = 0; 700 size_t count; 701 702 if (unlikely(pos + iov_iter_count(to) > size)) { 703 if (pos >= size) 704 return 0; 705 size -= pos; 706 shorted = iov_iter_count(to) - size; 707 iov_iter_truncate(to, size); 708 } 709 710 count = iov_iter_count(to); 711 if (!count) 712 goto reexpand; /* skip atime */ 713 714 if (iocb->ki_flags & IOCB_DIRECT) { 715 ret = kiocb_write_and_wait(iocb, count); 716 if (ret < 0) 717 goto reexpand; 718 file_accessed(iocb->ki_filp); 719 720 ret = blkdev_direct_IO(iocb, to); 721 if (ret >= 0) { 722 iocb->ki_pos += ret; 723 count -= ret; 724 } 725 iov_iter_revert(to, count - iov_iter_count(to)); 726 if (ret < 0 || !count) 727 goto reexpand; 728 } 729 730 ret = filemap_read(iocb, to, ret); 731 732 reexpand: 733 if (unlikely(shorted)) 734 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 735 return ret; 736 } 737 738 #define BLKDEV_FALLOC_FL_SUPPORTED \ 739 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 740 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) 741 742 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 743 loff_t len) 744 { 745 struct inode *inode = bdev_file_inode(file); 746 struct block_device *bdev = I_BDEV(inode); 747 loff_t end = start + len - 1; 748 loff_t isize; 749 int error; 750 751 /* Fail if we don't recognize the flags. */ 752 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 753 return -EOPNOTSUPP; 754 755 /* Don't go off the end of the device. */ 756 isize = bdev_nr_bytes(bdev); 757 if (start >= isize) 758 return -EINVAL; 759 if (end >= isize) { 760 if (mode & FALLOC_FL_KEEP_SIZE) { 761 len = isize - start; 762 end = start + len - 1; 763 } else 764 return -EINVAL; 765 } 766 767 /* 768 * Don't allow IO that isn't aligned to logical block size. 769 */ 770 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 771 return -EINVAL; 772 773 filemap_invalidate_lock(inode->i_mapping); 774 775 /* Invalidate the page cache, including dirty pages. */ 776 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 777 if (error) 778 goto fail; 779 780 switch (mode) { 781 case FALLOC_FL_ZERO_RANGE: 782 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 783 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 784 len >> SECTOR_SHIFT, GFP_KERNEL, 785 BLKDEV_ZERO_NOUNMAP); 786 break; 787 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 788 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 789 len >> SECTOR_SHIFT, GFP_KERNEL, 790 BLKDEV_ZERO_NOFALLBACK); 791 break; 792 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: 793 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, 794 len >> SECTOR_SHIFT, GFP_KERNEL); 795 break; 796 default: 797 error = -EOPNOTSUPP; 798 } 799 800 fail: 801 filemap_invalidate_unlock(inode->i_mapping); 802 return error; 803 } 804 805 static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) 806 { 807 struct inode *bd_inode = bdev_file_inode(file); 808 809 if (bdev_read_only(I_BDEV(bd_inode))) 810 return generic_file_readonly_mmap(file, vma); 811 812 return generic_file_mmap(file, vma); 813 } 814 815 const struct file_operations def_blk_fops = { 816 .open = blkdev_open, 817 .release = blkdev_release, 818 .llseek = blkdev_llseek, 819 .read_iter = blkdev_read_iter, 820 .write_iter = blkdev_write_iter, 821 .iopoll = iocb_bio_iopoll, 822 .mmap = blkdev_mmap, 823 .fsync = blkdev_fsync, 824 .unlocked_ioctl = blkdev_ioctl, 825 #ifdef CONFIG_COMPAT 826 .compat_ioctl = compat_blkdev_ioctl, 827 #endif 828 .splice_read = filemap_splice_read, 829 .splice_write = iter_file_splice_write, 830 .fallocate = blkdev_fallocate, 831 }; 832 833 static __init int blkdev_init(void) 834 { 835 return bioset_init(&blkdev_dio_pool, 4, 836 offsetof(struct blkdev_dio, bio), 837 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 838 } 839 module_init(blkdev_init); 840