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 22static inline struct inode *bdev_file_inode(struct file *file) 23{ 24 return file->f_mapping->host; 25} 26 27static 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 37static 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 46static 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_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 77 bio.bi_ioprio = iocb->ki_ioprio; 78 79 ret = bio_iov_iter_get_pages(&bio, iter); 80 if (unlikely(ret)) 81 goto out; 82 ret = bio.bi_iter.bi_size; 83 84 if (iov_iter_rw(iter) == WRITE) 85 task_io_account_write(ret); 86 87 if (iocb->ki_flags & IOCB_NOWAIT) 88 bio.bi_opf |= REQ_NOWAIT; 89 90 submit_bio_wait(&bio); 91 92 bio_release_pages(&bio, should_dirty); 93 if (unlikely(bio.bi_status)) 94 ret = blk_status_to_errno(bio.bi_status); 95 96out: 97 if (vecs != inline_vecs) 98 kfree(vecs); 99 100 bio_uninit(&bio); 101 102 return ret; 103} 104 105enum { 106 DIO_SHOULD_DIRTY = 1, 107 DIO_IS_SYNC = 2, 108}; 109 110struct blkdev_dio { 111 union { 112 struct kiocb *iocb; 113 struct task_struct *waiter; 114 }; 115 size_t size; 116 atomic_t ref; 117 unsigned int flags; 118 struct bio bio ____cacheline_aligned_in_smp; 119}; 120 121static struct bio_set blkdev_dio_pool; 122 123static void blkdev_bio_end_io(struct bio *bio) 124{ 125 struct blkdev_dio *dio = bio->bi_private; 126 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 127 128 if (bio->bi_status && !dio->bio.bi_status) 129 dio->bio.bi_status = bio->bi_status; 130 131 if (atomic_dec_and_test(&dio->ref)) { 132 if (!(dio->flags & DIO_IS_SYNC)) { 133 struct kiocb *iocb = dio->iocb; 134 ssize_t ret; 135 136 WRITE_ONCE(iocb->private, NULL); 137 138 if (likely(!dio->bio.bi_status)) { 139 ret = dio->size; 140 iocb->ki_pos += ret; 141 } else { 142 ret = blk_status_to_errno(dio->bio.bi_status); 143 } 144 145 dio->iocb->ki_complete(iocb, ret); 146 bio_put(&dio->bio); 147 } else { 148 struct task_struct *waiter = dio->waiter; 149 150 WRITE_ONCE(dio->waiter, NULL); 151 blk_wake_io_task(waiter); 152 } 153 } 154 155 if (should_dirty) { 156 bio_check_pages_dirty(bio); 157 } else { 158 bio_release_pages(bio, false); 159 bio_put(bio); 160 } 161} 162 163static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 164 unsigned int nr_pages) 165{ 166 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 167 struct blk_plug plug; 168 struct blkdev_dio *dio; 169 struct bio *bio; 170 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 171 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 172 loff_t pos = iocb->ki_pos; 173 int ret = 0; 174 175 if (blkdev_dio_unaligned(bdev, pos, iter)) 176 return -EINVAL; 177 178 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 179 opf |= REQ_ALLOC_CACHE; 180 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 181 &blkdev_dio_pool); 182 dio = container_of(bio, struct blkdev_dio, bio); 183 atomic_set(&dio->ref, 1); 184 /* 185 * Grab an extra reference to ensure the dio structure which is embedded 186 * into the first bio stays around. 187 */ 188 bio_get(bio); 189 190 is_sync = is_sync_kiocb(iocb); 191 if (is_sync) { 192 dio->flags = DIO_IS_SYNC; 193 dio->waiter = current; 194 } else { 195 dio->flags = 0; 196 dio->iocb = iocb; 197 } 198 199 dio->size = 0; 200 if (is_read && user_backed_iter(iter)) 201 dio->flags |= DIO_SHOULD_DIRTY; 202 203 blk_start_plug(&plug); 204 205 for (;;) { 206 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 207 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 208 bio->bi_private = dio; 209 bio->bi_end_io = blkdev_bio_end_io; 210 bio->bi_ioprio = iocb->ki_ioprio; 211 212 ret = bio_iov_iter_get_pages(bio, iter); 213 if (unlikely(ret)) { 214 bio->bi_status = BLK_STS_IOERR; 215 bio_endio(bio); 216 break; 217 } 218 if (iocb->ki_flags & IOCB_NOWAIT) { 219 /* 220 * This is nonblocking IO, and we need to allocate 221 * another bio if we have data left to map. As we 222 * cannot guarantee that one of the sub bios will not 223 * fail getting issued FOR NOWAIT and as error results 224 * are coalesced across all of them, be safe and ask for 225 * a retry of this from blocking context. 226 */ 227 if (unlikely(iov_iter_count(iter))) { 228 bio_release_pages(bio, false); 229 bio_clear_flag(bio, BIO_REFFED); 230 bio_put(bio); 231 blk_finish_plug(&plug); 232 return -EAGAIN; 233 } 234 bio->bi_opf |= REQ_NOWAIT; 235 } 236 237 if (is_read) { 238 if (dio->flags & DIO_SHOULD_DIRTY) 239 bio_set_pages_dirty(bio); 240 } else { 241 task_io_account_write(bio->bi_iter.bi_size); 242 } 243 dio->size += bio->bi_iter.bi_size; 244 pos += bio->bi_iter.bi_size; 245 246 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 247 if (!nr_pages) { 248 submit_bio(bio); 249 break; 250 } 251 atomic_inc(&dio->ref); 252 submit_bio(bio); 253 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 254 } 255 256 blk_finish_plug(&plug); 257 258 if (!is_sync) 259 return -EIOCBQUEUED; 260 261 for (;;) { 262 set_current_state(TASK_UNINTERRUPTIBLE); 263 if (!READ_ONCE(dio->waiter)) 264 break; 265 blk_io_schedule(); 266 } 267 __set_current_state(TASK_RUNNING); 268 269 if (!ret) 270 ret = blk_status_to_errno(dio->bio.bi_status); 271 if (likely(!ret)) 272 ret = dio->size; 273 274 bio_put(&dio->bio); 275 return ret; 276} 277 278static void blkdev_bio_end_io_async(struct bio *bio) 279{ 280 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 281 struct kiocb *iocb = dio->iocb; 282 ssize_t ret; 283 284 WRITE_ONCE(iocb->private, NULL); 285 286 if (likely(!bio->bi_status)) { 287 ret = dio->size; 288 iocb->ki_pos += ret; 289 } else { 290 ret = blk_status_to_errno(bio->bi_status); 291 } 292 293 iocb->ki_complete(iocb, ret); 294 295 if (dio->flags & DIO_SHOULD_DIRTY) { 296 bio_check_pages_dirty(bio); 297 } else { 298 bio_release_pages(bio, false); 299 bio_put(bio); 300 } 301} 302 303static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 304 struct iov_iter *iter, 305 unsigned int nr_pages) 306{ 307 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 308 bool is_read = iov_iter_rw(iter) == READ; 309 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 310 struct blkdev_dio *dio; 311 struct bio *bio; 312 loff_t pos = iocb->ki_pos; 313 int ret = 0; 314 315 if (blkdev_dio_unaligned(bdev, pos, iter)) 316 return -EINVAL; 317 318 if (iocb->ki_flags & IOCB_ALLOC_CACHE) 319 opf |= REQ_ALLOC_CACHE; 320 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL, 321 &blkdev_dio_pool); 322 dio = container_of(bio, struct blkdev_dio, bio); 323 dio->flags = 0; 324 dio->iocb = iocb; 325 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 326 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint; 327 bio->bi_end_io = blkdev_bio_end_io_async; 328 bio->bi_ioprio = iocb->ki_ioprio; 329 330 if (iov_iter_is_bvec(iter)) { 331 /* 332 * Users don't rely on the iterator being in any particular 333 * state for async I/O returning -EIOCBQUEUED, hence we can 334 * avoid expensive iov_iter_advance(). Bypass 335 * bio_iov_iter_get_pages() and set the bvec directly. 336 */ 337 bio_iov_bvec_set(bio, iter); 338 } else { 339 ret = bio_iov_iter_get_pages(bio, iter); 340 if (unlikely(ret)) { 341 bio_put(bio); 342 return ret; 343 } 344 } 345 dio->size = bio->bi_iter.bi_size; 346 347 if (is_read) { 348 if (user_backed_iter(iter)) { 349 dio->flags |= DIO_SHOULD_DIRTY; 350 bio_set_pages_dirty(bio); 351 } 352 } else { 353 task_io_account_write(bio->bi_iter.bi_size); 354 } 355 356 if (iocb->ki_flags & IOCB_NOWAIT) 357 bio->bi_opf |= REQ_NOWAIT; 358 359 if (iocb->ki_flags & IOCB_HIPRI) { 360 bio->bi_opf |= REQ_POLLED; 361 submit_bio(bio); 362 WRITE_ONCE(iocb->private, bio); 363 } else { 364 submit_bio(bio); 365 } 366 return -EIOCBQUEUED; 367} 368 369static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 370{ 371 unsigned int nr_pages; 372 373 if (!iov_iter_count(iter)) 374 return 0; 375 376 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 377 if (likely(nr_pages <= BIO_MAX_VECS)) { 378 if (is_sync_kiocb(iocb)) 379 return __blkdev_direct_IO_simple(iocb, iter, nr_pages); 380 return __blkdev_direct_IO_async(iocb, iter, nr_pages); 381 } 382 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages)); 383} 384 385static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 386 unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 387{ 388 struct block_device *bdev = I_BDEV(inode); 389 loff_t isize = i_size_read(inode); 390 391 iomap->bdev = bdev; 392 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev)); 393 if (iomap->offset >= isize) 394 return -EIO; 395 iomap->type = IOMAP_MAPPED; 396 iomap->addr = iomap->offset; 397 iomap->length = isize - iomap->offset; 398 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ 399 return 0; 400} 401 402static const struct iomap_ops blkdev_iomap_ops = { 403 .iomap_begin = blkdev_iomap_begin, 404}; 405 406#ifdef CONFIG_BUFFER_HEAD 407static int blkdev_get_block(struct inode *inode, sector_t iblock, 408 struct buffer_head *bh, int create) 409{ 410 bh->b_bdev = I_BDEV(inode); 411 bh->b_blocknr = iblock; 412 set_buffer_mapped(bh); 413 return 0; 414} 415 416/* 417 * We cannot call mpage_writepages() as it does not take the buffer lock. 418 * We must use block_write_full_folio() directly which holds the buffer 419 * lock. The buffer lock provides the synchronisation with writeback 420 * that filesystems rely on when they use the blockdev's mapping. 421 */ 422static int blkdev_writepages(struct address_space *mapping, 423 struct writeback_control *wbc) 424{ 425 struct blk_plug plug; 426 int err; 427 428 blk_start_plug(&plug); 429 err = write_cache_pages(mapping, wbc, block_write_full_folio, 430 blkdev_get_block); 431 blk_finish_plug(&plug); 432 433 return err; 434} 435 436static int blkdev_read_folio(struct file *file, struct folio *folio) 437{ 438 return block_read_full_folio(folio, blkdev_get_block); 439} 440 441static void blkdev_readahead(struct readahead_control *rac) 442{ 443 mpage_readahead(rac, blkdev_get_block); 444} 445 446static int blkdev_write_begin(struct file *file, struct address_space *mapping, 447 loff_t pos, unsigned len, struct page **pagep, void **fsdata) 448{ 449 return block_write_begin(mapping, pos, len, pagep, blkdev_get_block); 450} 451 452static int blkdev_write_end(struct file *file, struct address_space *mapping, 453 loff_t pos, unsigned len, unsigned copied, struct page *page, 454 void *fsdata) 455{ 456 int ret; 457 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); 458 459 unlock_page(page); 460 put_page(page); 461 462 return ret; 463} 464 465const struct address_space_operations def_blk_aops = { 466 .dirty_folio = block_dirty_folio, 467 .invalidate_folio = block_invalidate_folio, 468 .read_folio = blkdev_read_folio, 469 .readahead = blkdev_readahead, 470 .writepages = blkdev_writepages, 471 .write_begin = blkdev_write_begin, 472 .write_end = blkdev_write_end, 473 .migrate_folio = buffer_migrate_folio_norefs, 474 .is_dirty_writeback = buffer_check_dirty_writeback, 475}; 476#else /* CONFIG_BUFFER_HEAD */ 477static int blkdev_read_folio(struct file *file, struct folio *folio) 478{ 479 return iomap_read_folio(folio, &blkdev_iomap_ops); 480} 481 482static void blkdev_readahead(struct readahead_control *rac) 483{ 484 iomap_readahead(rac, &blkdev_iomap_ops); 485} 486 487static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc, 488 struct inode *inode, loff_t offset, unsigned int len) 489{ 490 loff_t isize = i_size_read(inode); 491 492 if (WARN_ON_ONCE(offset >= isize)) 493 return -EIO; 494 if (offset >= wpc->iomap.offset && 495 offset < wpc->iomap.offset + wpc->iomap.length) 496 return 0; 497 return blkdev_iomap_begin(inode, offset, isize - offset, 498 IOMAP_WRITE, &wpc->iomap, NULL); 499} 500 501static const struct iomap_writeback_ops blkdev_writeback_ops = { 502 .map_blocks = blkdev_map_blocks, 503}; 504 505static int blkdev_writepages(struct address_space *mapping, 506 struct writeback_control *wbc) 507{ 508 struct iomap_writepage_ctx wpc = { }; 509 510 return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops); 511} 512 513const struct address_space_operations def_blk_aops = { 514 .dirty_folio = filemap_dirty_folio, 515 .release_folio = iomap_release_folio, 516 .invalidate_folio = iomap_invalidate_folio, 517 .read_folio = blkdev_read_folio, 518 .readahead = blkdev_readahead, 519 .writepages = blkdev_writepages, 520 .is_partially_uptodate = iomap_is_partially_uptodate, 521 .error_remove_folio = generic_error_remove_folio, 522 .migrate_folio = filemap_migrate_folio, 523}; 524#endif /* CONFIG_BUFFER_HEAD */ 525 526/* 527 * for a block special file file_inode(file)->i_size is zero 528 * so we compute the size by hand (just as in block_read/write above) 529 */ 530static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 531{ 532 struct inode *bd_inode = bdev_file_inode(file); 533 loff_t retval; 534 535 inode_lock(bd_inode); 536 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 537 inode_unlock(bd_inode); 538 return retval; 539} 540 541static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 542 int datasync) 543{ 544 struct block_device *bdev = I_BDEV(filp->f_mapping->host); 545 int error; 546 547 error = file_write_and_wait_range(filp, start, end); 548 if (error) 549 return error; 550 551 /* 552 * There is no need to serialise calls to blkdev_issue_flush with 553 * i_mutex and doing so causes performance issues with concurrent 554 * O_SYNC writers to a block device. 555 */ 556 error = blkdev_issue_flush(bdev); 557 if (error == -EOPNOTSUPP) 558 error = 0; 559 560 return error; 561} 562 563/** 564 * file_to_blk_mode - get block open flags from file flags 565 * @file: file whose open flags should be converted 566 * 567 * Look at file open flags and generate corresponding block open flags from 568 * them. The function works both for file just being open (e.g. during ->open 569 * callback) and for file that is already open. This is actually non-trivial 570 * (see comment in the function). 571 */ 572blk_mode_t file_to_blk_mode(struct file *file) 573{ 574 blk_mode_t mode = 0; 575 576 if (file->f_mode & FMODE_READ) 577 mode |= BLK_OPEN_READ; 578 if (file->f_mode & FMODE_WRITE) 579 mode |= BLK_OPEN_WRITE; 580 /* 581 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data 582 * to determine whether the open was exclusive for already open files. 583 */ 584 if (file->private_data) 585 mode |= BLK_OPEN_EXCL; 586 else if (file->f_flags & O_EXCL) 587 mode |= BLK_OPEN_EXCL; 588 if (file->f_flags & O_NDELAY) 589 mode |= BLK_OPEN_NDELAY; 590 591 /* 592 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy 593 * driver has historically allowed ioctls as if the file was opened for 594 * writing, but does not allow and actual reads or writes. 595 */ 596 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY)) 597 mode |= BLK_OPEN_WRITE_IOCTL; 598 599 return mode; 600} 601 602static int blkdev_open(struct inode *inode, struct file *filp) 603{ 604 struct block_device *bdev; 605 blk_mode_t mode; 606 int ret; 607 608 mode = file_to_blk_mode(filp); 609 /* Use the file as the holder. */ 610 if (mode & BLK_OPEN_EXCL) 611 filp->private_data = filp; 612 ret = bdev_permission(inode->i_rdev, mode, filp->private_data); 613 if (ret) 614 return ret; 615 616 bdev = blkdev_get_no_open(inode->i_rdev); 617 if (!bdev) 618 return -ENXIO; 619 620 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp); 621 if (ret) 622 blkdev_put_no_open(bdev); 623 return ret; 624} 625 626static int blkdev_release(struct inode *inode, struct file *filp) 627{ 628 bdev_release(filp); 629 return 0; 630} 631 632static ssize_t 633blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from) 634{ 635 size_t count = iov_iter_count(from); 636 ssize_t written; 637 638 written = kiocb_invalidate_pages(iocb, count); 639 if (written) { 640 if (written == -EBUSY) 641 return 0; 642 return written; 643 } 644 645 written = blkdev_direct_IO(iocb, from); 646 if (written > 0) { 647 kiocb_invalidate_post_direct_write(iocb, count); 648 iocb->ki_pos += written; 649 count -= written; 650 } 651 if (written != -EIOCBQUEUED) 652 iov_iter_revert(from, count - iov_iter_count(from)); 653 return written; 654} 655 656static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from) 657{ 658 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops); 659} 660 661/* 662 * Write data to the block device. Only intended for the block device itself 663 * and the raw driver which basically is a fake block device. 664 * 665 * Does not take i_mutex for the write and thus is not for general purpose 666 * use. 667 */ 668static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 669{ 670 struct file *file = iocb->ki_filp; 671 struct block_device *bdev = I_BDEV(file->f_mapping->host); 672 struct inode *bd_inode = bdev->bd_inode; 673 loff_t size = bdev_nr_bytes(bdev); 674 size_t shorted = 0; 675 ssize_t ret; 676 677 if (bdev_read_only(bdev)) 678 return -EPERM; 679 680 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 681 return -ETXTBSY; 682 683 if (!iov_iter_count(from)) 684 return 0; 685 686 if (iocb->ki_pos >= size) 687 return -ENOSPC; 688 689 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 690 return -EOPNOTSUPP; 691 692 size -= iocb->ki_pos; 693 if (iov_iter_count(from) > size) { 694 shorted = iov_iter_count(from) - size; 695 iov_iter_truncate(from, size); 696 } 697 698 ret = file_update_time(file); 699 if (ret) 700 return ret; 701 702 if (iocb->ki_flags & IOCB_DIRECT) { 703 ret = blkdev_direct_write(iocb, from); 704 if (ret >= 0 && iov_iter_count(from)) 705 ret = direct_write_fallback(iocb, from, ret, 706 blkdev_buffered_write(iocb, from)); 707 } else { 708 ret = blkdev_buffered_write(iocb, from); 709 } 710 711 if (ret > 0) 712 ret = generic_write_sync(iocb, ret); 713 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 714 return ret; 715} 716 717static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 718{ 719 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host); 720 loff_t size = bdev_nr_bytes(bdev); 721 loff_t pos = iocb->ki_pos; 722 size_t shorted = 0; 723 ssize_t ret = 0; 724 size_t count; 725 726 if (unlikely(pos + iov_iter_count(to) > size)) { 727 if (pos >= size) 728 return 0; 729 size -= pos; 730 shorted = iov_iter_count(to) - size; 731 iov_iter_truncate(to, size); 732 } 733 734 count = iov_iter_count(to); 735 if (!count) 736 goto reexpand; /* skip atime */ 737 738 if (iocb->ki_flags & IOCB_DIRECT) { 739 ret = kiocb_write_and_wait(iocb, count); 740 if (ret < 0) 741 goto reexpand; 742 file_accessed(iocb->ki_filp); 743 744 ret = blkdev_direct_IO(iocb, to); 745 if (ret >= 0) { 746 iocb->ki_pos += ret; 747 count -= ret; 748 } 749 iov_iter_revert(to, count - iov_iter_count(to)); 750 if (ret < 0 || !count) 751 goto reexpand; 752 } 753 754 ret = filemap_read(iocb, to, ret); 755 756reexpand: 757 if (unlikely(shorted)) 758 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 759 return ret; 760} 761 762#define BLKDEV_FALLOC_FL_SUPPORTED \ 763 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 764 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) 765 766static long blkdev_fallocate(struct file *file, int mode, loff_t start, 767 loff_t len) 768{ 769 struct inode *inode = bdev_file_inode(file); 770 struct block_device *bdev = I_BDEV(inode); 771 loff_t end = start + len - 1; 772 loff_t isize; 773 int error; 774 775 /* Fail if we don't recognize the flags. */ 776 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 777 return -EOPNOTSUPP; 778 779 /* Don't go off the end of the device. */ 780 isize = bdev_nr_bytes(bdev); 781 if (start >= isize) 782 return -EINVAL; 783 if (end >= isize) { 784 if (mode & FALLOC_FL_KEEP_SIZE) { 785 len = isize - start; 786 end = start + len - 1; 787 } else 788 return -EINVAL; 789 } 790 791 /* 792 * Don't allow IO that isn't aligned to logical block size. 793 */ 794 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 795 return -EINVAL; 796 797 filemap_invalidate_lock(inode->i_mapping); 798 799 /* 800 * Invalidate the page cache, including dirty pages, for valid 801 * de-allocate mode calls to fallocate(). 802 */ 803 switch (mode) { 804 case FALLOC_FL_ZERO_RANGE: 805 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 806 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 807 if (error) 808 goto fail; 809 810 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 811 len >> SECTOR_SHIFT, GFP_KERNEL, 812 BLKDEV_ZERO_NOUNMAP); 813 break; 814 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 815 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 816 if (error) 817 goto fail; 818 819 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 820 len >> SECTOR_SHIFT, GFP_KERNEL, 821 BLKDEV_ZERO_NOFALLBACK); 822 break; 823 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: 824 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end); 825 if (error) 826 goto fail; 827 828 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, 829 len >> SECTOR_SHIFT, GFP_KERNEL); 830 break; 831 default: 832 error = -EOPNOTSUPP; 833 } 834 835 fail: 836 filemap_invalidate_unlock(inode->i_mapping); 837 return error; 838} 839 840static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) 841{ 842 struct inode *bd_inode = bdev_file_inode(file); 843 844 if (bdev_read_only(I_BDEV(bd_inode))) 845 return generic_file_readonly_mmap(file, vma); 846 847 return generic_file_mmap(file, vma); 848} 849 850const struct file_operations def_blk_fops = { 851 .open = blkdev_open, 852 .release = blkdev_release, 853 .llseek = blkdev_llseek, 854 .read_iter = blkdev_read_iter, 855 .write_iter = blkdev_write_iter, 856 .iopoll = iocb_bio_iopoll, 857 .mmap = blkdev_mmap, 858 .fsync = blkdev_fsync, 859 .unlocked_ioctl = blkdev_ioctl, 860#ifdef CONFIG_COMPAT 861 .compat_ioctl = compat_blkdev_ioctl, 862#endif 863 .splice_read = filemap_splice_read, 864 .splice_write = iter_file_splice_write, 865 .fallocate = blkdev_fallocate, 866}; 867 868static __init int blkdev_init(void) 869{ 870 return bioset_init(&blkdev_dio_pool, 4, 871 offsetof(struct blkdev_dio, bio), 872 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 873} 874module_init(blkdev_init); 875