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/module.h> 19 #include "blk.h" 20 21 static inline struct inode *bdev_file_inode(struct file *file) 22 { 23 return file->f_mapping->host; 24 } 25 26 static int blkdev_get_block(struct inode *inode, sector_t iblock, 27 struct buffer_head *bh, int create) 28 { 29 bh->b_bdev = I_BDEV(inode); 30 bh->b_blocknr = iblock; 31 set_buffer_mapped(bh); 32 return 0; 33 } 34 35 static unsigned int dio_bio_write_op(struct kiocb *iocb) 36 { 37 unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; 38 39 /* avoid the need for a I/O completion work item */ 40 if (iocb->ki_flags & IOCB_DSYNC) 41 op |= REQ_FUA; 42 return op; 43 } 44 45 #define DIO_INLINE_BIO_VECS 4 46 47 static void blkdev_bio_end_io_simple(struct bio *bio) 48 { 49 struct task_struct *waiter = bio->bi_private; 50 51 WRITE_ONCE(bio->bi_private, NULL); 52 blk_wake_io_task(waiter); 53 } 54 55 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, 56 struct iov_iter *iter, unsigned int nr_pages) 57 { 58 struct block_device *bdev = iocb->ki_filp->private_data; 59 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; 60 loff_t pos = iocb->ki_pos; 61 bool should_dirty = false; 62 struct bio bio; 63 ssize_t ret; 64 65 if ((pos | iov_iter_alignment(iter)) & 66 (bdev_logical_block_size(bdev) - 1)) 67 return -EINVAL; 68 69 if (nr_pages <= DIO_INLINE_BIO_VECS) 70 vecs = inline_vecs; 71 else { 72 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec), 73 GFP_KERNEL); 74 if (!vecs) 75 return -ENOMEM; 76 } 77 78 bio_init(&bio, vecs, nr_pages); 79 bio_set_dev(&bio, bdev); 80 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 81 bio.bi_write_hint = iocb->ki_hint; 82 bio.bi_private = current; 83 bio.bi_end_io = blkdev_bio_end_io_simple; 84 bio.bi_ioprio = iocb->ki_ioprio; 85 86 ret = bio_iov_iter_get_pages(&bio, iter); 87 if (unlikely(ret)) 88 goto out; 89 ret = bio.bi_iter.bi_size; 90 91 if (iov_iter_rw(iter) == READ) { 92 bio.bi_opf = REQ_OP_READ; 93 if (iter_is_iovec(iter)) 94 should_dirty = true; 95 } else { 96 bio.bi_opf = dio_bio_write_op(iocb); 97 task_io_account_write(ret); 98 } 99 if (iocb->ki_flags & IOCB_NOWAIT) 100 bio.bi_opf |= REQ_NOWAIT; 101 if (iocb->ki_flags & IOCB_HIPRI) 102 bio_set_polled(&bio, iocb); 103 104 submit_bio(&bio); 105 for (;;) { 106 set_current_state(TASK_UNINTERRUPTIBLE); 107 if (!READ_ONCE(bio.bi_private)) 108 break; 109 if (!(iocb->ki_flags & IOCB_HIPRI) || !bio_poll(&bio, NULL, 0)) 110 blk_io_schedule(); 111 } 112 __set_current_state(TASK_RUNNING); 113 114 bio_release_pages(&bio, should_dirty); 115 if (unlikely(bio.bi_status)) 116 ret = blk_status_to_errno(bio.bi_status); 117 118 out: 119 if (vecs != inline_vecs) 120 kfree(vecs); 121 122 bio_uninit(&bio); 123 124 return ret; 125 } 126 127 enum { 128 DIO_SHOULD_DIRTY = 1, 129 DIO_IS_SYNC = 2, 130 }; 131 132 struct blkdev_dio { 133 union { 134 struct kiocb *iocb; 135 struct task_struct *waiter; 136 }; 137 size_t size; 138 atomic_t ref; 139 unsigned int flags; 140 struct bio bio ____cacheline_aligned_in_smp; 141 }; 142 143 static struct bio_set blkdev_dio_pool; 144 145 static void blkdev_bio_end_io(struct bio *bio) 146 { 147 struct blkdev_dio *dio = bio->bi_private; 148 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 149 150 if (bio->bi_status && !dio->bio.bi_status) 151 dio->bio.bi_status = bio->bi_status; 152 153 if (atomic_dec_and_test(&dio->ref)) { 154 if (!(dio->flags & DIO_IS_SYNC)) { 155 struct kiocb *iocb = dio->iocb; 156 ssize_t ret; 157 158 WRITE_ONCE(iocb->private, NULL); 159 160 if (likely(!dio->bio.bi_status)) { 161 ret = dio->size; 162 iocb->ki_pos += ret; 163 } else { 164 ret = blk_status_to_errno(dio->bio.bi_status); 165 } 166 167 dio->iocb->ki_complete(iocb, ret); 168 bio_put(&dio->bio); 169 } else { 170 struct task_struct *waiter = dio->waiter; 171 172 WRITE_ONCE(dio->waiter, NULL); 173 blk_wake_io_task(waiter); 174 } 175 } 176 177 if (should_dirty) { 178 bio_check_pages_dirty(bio); 179 } else { 180 bio_release_pages(bio, false); 181 bio_put(bio); 182 } 183 } 184 185 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 186 unsigned int nr_pages) 187 { 188 struct block_device *bdev = iocb->ki_filp->private_data; 189 struct blk_plug plug; 190 struct blkdev_dio *dio; 191 struct bio *bio; 192 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 193 loff_t pos = iocb->ki_pos; 194 int ret = 0; 195 196 if ((pos | iov_iter_alignment(iter)) & 197 (bdev_logical_block_size(bdev) - 1)) 198 return -EINVAL; 199 200 bio = bio_alloc_kiocb(iocb, nr_pages, &blkdev_dio_pool); 201 202 dio = container_of(bio, struct blkdev_dio, bio); 203 atomic_set(&dio->ref, 1); 204 /* 205 * Grab an extra reference to ensure the dio structure which is embedded 206 * into the first bio stays around. 207 */ 208 bio_get(bio); 209 210 is_sync = is_sync_kiocb(iocb); 211 if (is_sync) { 212 dio->flags = DIO_IS_SYNC; 213 dio->waiter = current; 214 } else { 215 dio->flags = 0; 216 dio->iocb = iocb; 217 } 218 219 dio->size = 0; 220 if (is_read && iter_is_iovec(iter)) 221 dio->flags |= DIO_SHOULD_DIRTY; 222 223 blk_start_plug(&plug); 224 225 for (;;) { 226 bio_set_dev(bio, bdev); 227 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 228 bio->bi_write_hint = iocb->ki_hint; 229 bio->bi_private = dio; 230 bio->bi_end_io = blkdev_bio_end_io; 231 bio->bi_ioprio = iocb->ki_ioprio; 232 233 ret = bio_iov_iter_get_pages(bio, iter); 234 if (unlikely(ret)) { 235 bio->bi_status = BLK_STS_IOERR; 236 bio_endio(bio); 237 break; 238 } 239 240 if (is_read) { 241 bio->bi_opf = REQ_OP_READ; 242 if (dio->flags & DIO_SHOULD_DIRTY) 243 bio_set_pages_dirty(bio); 244 } else { 245 bio->bi_opf = dio_bio_write_op(iocb); 246 task_io_account_write(bio->bi_iter.bi_size); 247 } 248 if (iocb->ki_flags & IOCB_NOWAIT) 249 bio->bi_opf |= REQ_NOWAIT; 250 251 dio->size += bio->bi_iter.bi_size; 252 pos += bio->bi_iter.bi_size; 253 254 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 255 if (!nr_pages) { 256 submit_bio(bio); 257 break; 258 } 259 atomic_inc(&dio->ref); 260 submit_bio(bio); 261 bio = bio_alloc(GFP_KERNEL, nr_pages); 262 } 263 264 blk_finish_plug(&plug); 265 266 if (!is_sync) 267 return -EIOCBQUEUED; 268 269 for (;;) { 270 set_current_state(TASK_UNINTERRUPTIBLE); 271 if (!READ_ONCE(dio->waiter)) 272 break; 273 blk_io_schedule(); 274 } 275 __set_current_state(TASK_RUNNING); 276 277 if (!ret) 278 ret = blk_status_to_errno(dio->bio.bi_status); 279 if (likely(!ret)) 280 ret = dio->size; 281 282 bio_put(&dio->bio); 283 return ret; 284 } 285 286 static void blkdev_bio_end_io_async(struct bio *bio) 287 { 288 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 289 struct kiocb *iocb = dio->iocb; 290 ssize_t ret; 291 292 if (likely(!bio->bi_status)) { 293 ret = dio->size; 294 iocb->ki_pos += ret; 295 } else { 296 ret = blk_status_to_errno(bio->bi_status); 297 } 298 299 iocb->ki_complete(iocb, ret); 300 301 if (dio->flags & DIO_SHOULD_DIRTY) { 302 bio_check_pages_dirty(bio); 303 } else { 304 bio_release_pages(bio, false); 305 bio_put(bio); 306 } 307 } 308 309 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 310 struct iov_iter *iter, 311 unsigned int nr_pages) 312 { 313 struct block_device *bdev = iocb->ki_filp->private_data; 314 struct blkdev_dio *dio; 315 struct bio *bio; 316 loff_t pos = iocb->ki_pos; 317 int ret = 0; 318 319 if ((pos | iov_iter_alignment(iter)) & 320 (bdev_logical_block_size(bdev) - 1)) 321 return -EINVAL; 322 323 bio = bio_alloc_kiocb(iocb, nr_pages, &blkdev_dio_pool); 324 dio = container_of(bio, struct blkdev_dio, bio); 325 dio->flags = 0; 326 dio->iocb = iocb; 327 bio_set_dev(bio, bdev); 328 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 329 bio->bi_write_hint = iocb->ki_hint; 330 bio->bi_end_io = blkdev_bio_end_io_async; 331 bio->bi_ioprio = iocb->ki_ioprio; 332 333 if (iov_iter_is_bvec(iter)) { 334 /* 335 * Users don't rely on the iterator being in any particular 336 * state for async I/O returning -EIOCBQUEUED, hence we can 337 * avoid expensive iov_iter_advance(). Bypass 338 * bio_iov_iter_get_pages() and set the bvec directly. 339 */ 340 bio_iov_bvec_set(bio, iter); 341 } else { 342 ret = bio_iov_iter_get_pages(bio, iter); 343 if (unlikely(ret)) { 344 bio_put(bio); 345 return ret; 346 } 347 } 348 dio->size = bio->bi_iter.bi_size; 349 350 if (iov_iter_rw(iter) == READ) { 351 bio->bi_opf = REQ_OP_READ; 352 if (iter_is_iovec(iter)) { 353 dio->flags |= DIO_SHOULD_DIRTY; 354 bio_set_pages_dirty(bio); 355 } 356 } else { 357 bio->bi_opf = dio_bio_write_op(iocb); 358 task_io_account_write(bio->bi_iter.bi_size); 359 } 360 361 if (iocb->ki_flags & IOCB_HIPRI) { 362 bio->bi_opf |= REQ_POLLED | REQ_NOWAIT; 363 submit_bio(bio); 364 WRITE_ONCE(iocb->private, bio); 365 } else { 366 if (iocb->ki_flags & IOCB_NOWAIT) 367 bio->bi_opf |= REQ_NOWAIT; 368 submit_bio(bio); 369 } 370 return -EIOCBQUEUED; 371 } 372 373 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 374 { 375 unsigned int nr_pages; 376 377 if (!iov_iter_count(iter)) 378 return 0; 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, nr_pages); 384 return __blkdev_direct_IO_async(iocb, iter, nr_pages); 385 } 386 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages)); 387 } 388 389 static int blkdev_writepage(struct page *page, struct writeback_control *wbc) 390 { 391 return block_write_full_page(page, blkdev_get_block, wbc); 392 } 393 394 static int blkdev_readpage(struct file * file, struct page * page) 395 { 396 return block_read_full_page(page, blkdev_get_block); 397 } 398 399 static void blkdev_readahead(struct readahead_control *rac) 400 { 401 mpage_readahead(rac, blkdev_get_block); 402 } 403 404 static int blkdev_write_begin(struct file *file, struct address_space *mapping, 405 loff_t pos, unsigned len, unsigned flags, struct page **pagep, 406 void **fsdata) 407 { 408 return block_write_begin(mapping, pos, len, flags, pagep, 409 blkdev_get_block); 410 } 411 412 static int blkdev_write_end(struct file *file, struct address_space *mapping, 413 loff_t pos, unsigned len, unsigned copied, struct page *page, 414 void *fsdata) 415 { 416 int ret; 417 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); 418 419 unlock_page(page); 420 put_page(page); 421 422 return ret; 423 } 424 425 static int blkdev_writepages(struct address_space *mapping, 426 struct writeback_control *wbc) 427 { 428 return generic_writepages(mapping, wbc); 429 } 430 431 const struct address_space_operations def_blk_aops = { 432 .set_page_dirty = __set_page_dirty_buffers, 433 .readpage = blkdev_readpage, 434 .readahead = blkdev_readahead, 435 .writepage = blkdev_writepage, 436 .write_begin = blkdev_write_begin, 437 .write_end = blkdev_write_end, 438 .writepages = blkdev_writepages, 439 .direct_IO = blkdev_direct_IO, 440 .migratepage = buffer_migrate_page_norefs, 441 .is_dirty_writeback = buffer_check_dirty_writeback, 442 }; 443 444 /* 445 * for a block special file file_inode(file)->i_size is zero 446 * so we compute the size by hand (just as in block_read/write above) 447 */ 448 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 449 { 450 struct inode *bd_inode = bdev_file_inode(file); 451 loff_t retval; 452 453 inode_lock(bd_inode); 454 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 455 inode_unlock(bd_inode); 456 return retval; 457 } 458 459 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 460 int datasync) 461 { 462 struct block_device *bdev = filp->private_data; 463 int error; 464 465 error = file_write_and_wait_range(filp, start, end); 466 if (error) 467 return error; 468 469 /* 470 * There is no need to serialise calls to blkdev_issue_flush with 471 * i_mutex and doing so causes performance issues with concurrent 472 * O_SYNC writers to a block device. 473 */ 474 error = blkdev_issue_flush(bdev); 475 if (error == -EOPNOTSUPP) 476 error = 0; 477 478 return error; 479 } 480 481 static int blkdev_open(struct inode *inode, struct file *filp) 482 { 483 struct block_device *bdev; 484 485 /* 486 * Preserve backwards compatibility and allow large file access 487 * even if userspace doesn't ask for it explicitly. Some mkfs 488 * binary needs it. We might want to drop this workaround 489 * during an unstable branch. 490 */ 491 filp->f_flags |= O_LARGEFILE; 492 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC; 493 494 if (filp->f_flags & O_NDELAY) 495 filp->f_mode |= FMODE_NDELAY; 496 if (filp->f_flags & O_EXCL) 497 filp->f_mode |= FMODE_EXCL; 498 if ((filp->f_flags & O_ACCMODE) == 3) 499 filp->f_mode |= FMODE_WRITE_IOCTL; 500 501 bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp); 502 if (IS_ERR(bdev)) 503 return PTR_ERR(bdev); 504 505 filp->private_data = bdev; 506 filp->f_mapping = bdev->bd_inode->i_mapping; 507 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); 508 return 0; 509 } 510 511 static int blkdev_close(struct inode *inode, struct file *filp) 512 { 513 struct block_device *bdev = filp->private_data; 514 515 blkdev_put(bdev, filp->f_mode); 516 return 0; 517 } 518 519 /* 520 * Write data to the block device. Only intended for the block device itself 521 * and the raw driver which basically is a fake block device. 522 * 523 * Does not take i_mutex for the write and thus is not for general purpose 524 * use. 525 */ 526 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 527 { 528 struct block_device *bdev = iocb->ki_filp->private_data; 529 struct inode *bd_inode = bdev->bd_inode; 530 loff_t size = bdev_nr_bytes(bdev); 531 struct blk_plug plug; 532 size_t shorted = 0; 533 ssize_t ret; 534 535 if (bdev_read_only(bdev)) 536 return -EPERM; 537 538 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 539 return -ETXTBSY; 540 541 if (!iov_iter_count(from)) 542 return 0; 543 544 if (iocb->ki_pos >= size) 545 return -ENOSPC; 546 547 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 548 return -EOPNOTSUPP; 549 550 size -= iocb->ki_pos; 551 if (iov_iter_count(from) > size) { 552 shorted = iov_iter_count(from) - size; 553 iov_iter_truncate(from, size); 554 } 555 556 blk_start_plug(&plug); 557 ret = __generic_file_write_iter(iocb, from); 558 if (ret > 0) 559 ret = generic_write_sync(iocb, ret); 560 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 561 blk_finish_plug(&plug); 562 return ret; 563 } 564 565 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 566 { 567 struct block_device *bdev = iocb->ki_filp->private_data; 568 loff_t size = bdev_nr_bytes(bdev); 569 loff_t pos = iocb->ki_pos; 570 size_t shorted = 0; 571 ssize_t ret; 572 573 if (unlikely(pos + iov_iter_count(to) > size)) { 574 if (pos >= size) 575 return 0; 576 size -= pos; 577 if (iov_iter_count(to) > size) { 578 shorted = iov_iter_count(to) - size; 579 iov_iter_truncate(to, size); 580 } 581 } 582 583 ret = generic_file_read_iter(iocb, to); 584 585 if (unlikely(shorted)) 586 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 587 return ret; 588 } 589 590 #define BLKDEV_FALLOC_FL_SUPPORTED \ 591 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 592 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) 593 594 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 595 loff_t len) 596 { 597 struct inode *inode = bdev_file_inode(file); 598 struct block_device *bdev = I_BDEV(inode); 599 loff_t end = start + len - 1; 600 loff_t isize; 601 int error; 602 603 /* Fail if we don't recognize the flags. */ 604 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 605 return -EOPNOTSUPP; 606 607 /* Don't go off the end of the device. */ 608 isize = bdev_nr_bytes(bdev); 609 if (start >= isize) 610 return -EINVAL; 611 if (end >= isize) { 612 if (mode & FALLOC_FL_KEEP_SIZE) { 613 len = isize - start; 614 end = start + len - 1; 615 } else 616 return -EINVAL; 617 } 618 619 /* 620 * Don't allow IO that isn't aligned to logical block size. 621 */ 622 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 623 return -EINVAL; 624 625 filemap_invalidate_lock(inode->i_mapping); 626 627 /* Invalidate the page cache, including dirty pages. */ 628 error = truncate_bdev_range(bdev, file->f_mode, start, end); 629 if (error) 630 goto fail; 631 632 switch (mode) { 633 case FALLOC_FL_ZERO_RANGE: 634 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 635 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 636 len >> SECTOR_SHIFT, GFP_KERNEL, 637 BLKDEV_ZERO_NOUNMAP); 638 break; 639 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 640 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 641 len >> SECTOR_SHIFT, GFP_KERNEL, 642 BLKDEV_ZERO_NOFALLBACK); 643 break; 644 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: 645 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, 646 len >> SECTOR_SHIFT, GFP_KERNEL, 0); 647 break; 648 default: 649 error = -EOPNOTSUPP; 650 } 651 652 fail: 653 filemap_invalidate_unlock(inode->i_mapping); 654 return error; 655 } 656 657 const struct file_operations def_blk_fops = { 658 .open = blkdev_open, 659 .release = blkdev_close, 660 .llseek = blkdev_llseek, 661 .read_iter = blkdev_read_iter, 662 .write_iter = blkdev_write_iter, 663 .iopoll = iocb_bio_iopoll, 664 .mmap = generic_file_mmap, 665 .fsync = blkdev_fsync, 666 .unlocked_ioctl = blkdev_ioctl, 667 #ifdef CONFIG_COMPAT 668 .compat_ioctl = compat_blkdev_ioctl, 669 #endif 670 .splice_read = generic_file_splice_read, 671 .splice_write = iter_file_splice_write, 672 .fallocate = blkdev_fallocate, 673 }; 674 675 static __init int blkdev_init(void) 676 { 677 return bioset_init(&blkdev_dio_pool, 4, 678 offsetof(struct blkdev_dio, bio), 679 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 680 } 681 module_init(blkdev_init); 682