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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 1991, 1992 Linus Torvalds4 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE5 * Copyright (C) 2016 - 2020 Christoph Hellwig6 */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 <linux/io_uring/cmd.h>21#include "blk.h"22 23static inline struct inode *bdev_file_inode(struct file *file)24{25 return file->f_mapping->host;26}27 28static blk_opf_t dio_bio_write_op(struct kiocb *iocb)29{30 blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;31 32 /* avoid the need for a I/O completion work item */33 if (iocb_is_dsync(iocb))34 opf |= REQ_FUA;35 return opf;36}37 38static bool blkdev_dio_invalid(struct block_device *bdev, loff_t pos,39 struct iov_iter *iter, bool is_atomic)40{41 if (is_atomic && !generic_atomic_write_valid(iter, pos))42 return true;43 44 return pos & (bdev_logical_block_size(bdev) - 1) ||45 !bdev_iter_is_aligned(bdev, iter);46}47 48#define DIO_INLINE_BIO_VECS 449 50static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,51 struct iov_iter *iter, struct block_device *bdev,52 unsigned int nr_pages)53{54 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;55 loff_t pos = iocb->ki_pos;56 bool should_dirty = false;57 struct bio bio;58 ssize_t ret;59 60 if (nr_pages <= DIO_INLINE_BIO_VECS)61 vecs = inline_vecs;62 else {63 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),64 GFP_KERNEL);65 if (!vecs)66 return -ENOMEM;67 }68 69 if (iov_iter_rw(iter) == READ) {70 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);71 if (user_backed_iter(iter))72 should_dirty = true;73 } else {74 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));75 }76 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;77 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;78 bio.bi_ioprio = iocb->ki_ioprio;79 if (iocb->ki_flags & IOCB_ATOMIC)80 bio.bi_opf |= REQ_ATOMIC;81 82 ret = bio_iov_iter_get_pages(&bio, iter);83 if (unlikely(ret))84 goto out;85 ret = bio.bi_iter.bi_size;86 87 if (iov_iter_rw(iter) == WRITE)88 task_io_account_write(ret);89 90 if (iocb->ki_flags & IOCB_NOWAIT)91 bio.bi_opf |= REQ_NOWAIT;92 93 submit_bio_wait(&bio);94 95 bio_release_pages(&bio, should_dirty);96 if (unlikely(bio.bi_status))97 ret = blk_status_to_errno(bio.bi_status);98 99out:100 if (vecs != inline_vecs)101 kfree(vecs);102 103 bio_uninit(&bio);104 105 return ret;106}107 108enum {109 DIO_SHOULD_DIRTY = 1,110 DIO_IS_SYNC = 2,111};112 113struct blkdev_dio {114 union {115 struct kiocb *iocb;116 struct task_struct *waiter;117 };118 size_t size;119 atomic_t ref;120 unsigned int flags;121 struct bio bio ____cacheline_aligned_in_smp;122};123 124static struct bio_set blkdev_dio_pool;125 126static void blkdev_bio_end_io(struct bio *bio)127{128 struct blkdev_dio *dio = bio->bi_private;129 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;130 131 if (bio->bi_status && !dio->bio.bi_status)132 dio->bio.bi_status = bio->bi_status;133 134 if (atomic_dec_and_test(&dio->ref)) {135 if (!(dio->flags & DIO_IS_SYNC)) {136 struct kiocb *iocb = dio->iocb;137 ssize_t ret;138 139 WRITE_ONCE(iocb->private, NULL);140 141 if (likely(!dio->bio.bi_status)) {142 ret = dio->size;143 iocb->ki_pos += ret;144 } else {145 ret = blk_status_to_errno(dio->bio.bi_status);146 }147 148 dio->iocb->ki_complete(iocb, ret);149 bio_put(&dio->bio);150 } else {151 struct task_struct *waiter = dio->waiter;152 153 WRITE_ONCE(dio->waiter, NULL);154 blk_wake_io_task(waiter);155 }156 }157 158 if (should_dirty) {159 bio_check_pages_dirty(bio);160 } else {161 bio_release_pages(bio, false);162 bio_put(bio);163 }164}165 166static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,167 struct block_device *bdev, unsigned int nr_pages)168{169 struct blk_plug plug;170 struct blkdev_dio *dio;171 struct bio *bio;172 bool is_read = (iov_iter_rw(iter) == READ), is_sync;173 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);174 loff_t pos = iocb->ki_pos;175 int ret = 0;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 embedded185 * 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_write_hint = file_inode(iocb->ki_filp)->i_write_hint;207 bio->bi_private = dio;208 bio->bi_end_io = blkdev_bio_end_io;209 bio->bi_ioprio = iocb->ki_ioprio;210 211 ret = bio_iov_iter_get_pages(bio, iter);212 if (unlikely(ret)) {213 bio->bi_status = BLK_STS_IOERR;214 bio_endio(bio);215 break;216 }217 if (iocb->ki_flags & IOCB_NOWAIT) {218 /*219 * This is nonblocking IO, and we need to allocate220 * another bio if we have data left to map. As we221 * cannot guarantee that one of the sub bios will not222 * fail getting issued FOR NOWAIT and as error results223 * are coalesced across all of them, be safe and ask for224 * a retry of this from blocking context.225 */226 if (unlikely(iov_iter_count(iter))) {227 bio_release_pages(bio, false);228 bio_clear_flag(bio, BIO_REFFED);229 bio_put(bio);230 blk_finish_plug(&plug);231 return -EAGAIN;232 }233 bio->bi_opf |= REQ_NOWAIT;234 }235 236 if (is_read) {237 if (dio->flags & DIO_SHOULD_DIRTY)238 bio_set_pages_dirty(bio);239 } else {240 task_io_account_write(bio->bi_iter.bi_size);241 }242 dio->size += bio->bi_iter.bi_size;243 pos += bio->bi_iter.bi_size;244 245 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);246 if (!nr_pages) {247 submit_bio(bio);248 break;249 }250 atomic_inc(&dio->ref);251 submit_bio(bio);252 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);253 }254 255 blk_finish_plug(&plug);256 257 if (!is_sync)258 return -EIOCBQUEUED;259 260 for (;;) {261 set_current_state(TASK_UNINTERRUPTIBLE);262 if (!READ_ONCE(dio->waiter))263 break;264 blk_io_schedule();265 }266 __set_current_state(TASK_RUNNING);267 268 if (!ret)269 ret = blk_status_to_errno(dio->bio.bi_status);270 if (likely(!ret))271 ret = dio->size;272 273 bio_put(&dio->bio);274 return ret;275}276 277static void blkdev_bio_end_io_async(struct bio *bio)278{279 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);280 struct kiocb *iocb = dio->iocb;281 ssize_t ret;282 283 WRITE_ONCE(iocb->private, NULL);284 285 if (likely(!bio->bi_status)) {286 ret = dio->size;287 iocb->ki_pos += ret;288 } else {289 ret = blk_status_to_errno(bio->bi_status);290 }291 292 iocb->ki_complete(iocb, ret);293 294 if (dio->flags & DIO_SHOULD_DIRTY) {295 bio_check_pages_dirty(bio);296 } else {297 bio_release_pages(bio, false);298 bio_put(bio);299 }300}301 302static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,303 struct iov_iter *iter,304 struct block_device *bdev,305 unsigned int nr_pages)306{307 bool is_read = iov_iter_rw(iter) == READ;308 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);309 struct blkdev_dio *dio;310 struct bio *bio;311 loff_t pos = iocb->ki_pos;312 int ret = 0;313 314 if (iocb->ki_flags & IOCB_ALLOC_CACHE)315 opf |= REQ_ALLOC_CACHE;316 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,317 &blkdev_dio_pool);318 dio = container_of(bio, struct blkdev_dio, bio);319 dio->flags = 0;320 dio->iocb = iocb;321 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;322 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;323 bio->bi_end_io = blkdev_bio_end_io_async;324 bio->bi_ioprio = iocb->ki_ioprio;325 326 if (iov_iter_is_bvec(iter)) {327 /*328 * Users don't rely on the iterator being in any particular329 * state for async I/O returning -EIOCBQUEUED, hence we can330 * avoid expensive iov_iter_advance(). Bypass331 * bio_iov_iter_get_pages() and set the bvec directly.332 */333 bio_iov_bvec_set(bio, iter);334 } else {335 ret = bio_iov_iter_get_pages(bio, iter);336 if (unlikely(ret)) {337 bio_put(bio);338 return ret;339 }340 }341 dio->size = bio->bi_iter.bi_size;342 343 if (is_read) {344 if (user_backed_iter(iter)) {345 dio->flags |= DIO_SHOULD_DIRTY;346 bio_set_pages_dirty(bio);347 }348 } else {349 task_io_account_write(bio->bi_iter.bi_size);350 }351 352 if (iocb->ki_flags & IOCB_ATOMIC)353 bio->bi_opf |= REQ_ATOMIC;354 355 if (iocb->ki_flags & IOCB_NOWAIT)356 bio->bi_opf |= REQ_NOWAIT;357 358 if (iocb->ki_flags & IOCB_HIPRI) {359 bio->bi_opf |= REQ_POLLED;360 submit_bio(bio);361 WRITE_ONCE(iocb->private, bio);362 } else {363 submit_bio(bio);364 }365 return -EIOCBQUEUED;366}367 368static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)369{370 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);371 bool is_atomic = iocb->ki_flags & IOCB_ATOMIC;372 unsigned int nr_pages;373 374 if (!iov_iter_count(iter))375 return 0;376 377 if (blkdev_dio_invalid(bdev, iocb->ki_pos, iter, is_atomic))378 return -EINVAL;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, bdev,384 nr_pages);385 return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);386 } else if (is_atomic) {387 return -EINVAL;388 }389 return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));390}391 392static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,393 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)394{395 struct block_device *bdev = I_BDEV(inode);396 loff_t isize = i_size_read(inode);397 398 if (offset >= isize)399 return -EIO;400 401 iomap->bdev = bdev;402 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));403 iomap->type = IOMAP_MAPPED;404 iomap->addr = iomap->offset;405 iomap->length = isize - iomap->offset;406 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */407 return 0;408}409 410static const struct iomap_ops blkdev_iomap_ops = {411 .iomap_begin = blkdev_iomap_begin,412};413 414#ifdef CONFIG_BUFFER_HEAD415static int blkdev_get_block(struct inode *inode, sector_t iblock,416 struct buffer_head *bh, int create)417{418 bh->b_bdev = I_BDEV(inode);419 bh->b_blocknr = iblock;420 set_buffer_mapped(bh);421 return 0;422}423 424/*425 * We cannot call mpage_writepages() as it does not take the buffer lock.426 * We must use block_write_full_folio() directly which holds the buffer427 * lock. The buffer lock provides the synchronisation with writeback428 * that filesystems rely on when they use the blockdev's mapping.429 */430static int blkdev_writepages(struct address_space *mapping,431 struct writeback_control *wbc)432{433 struct blk_plug plug;434 int err;435 436 blk_start_plug(&plug);437 err = write_cache_pages(mapping, wbc, block_write_full_folio,438 blkdev_get_block);439 blk_finish_plug(&plug);440 441 return err;442}443 444static int blkdev_read_folio(struct file *file, struct folio *folio)445{446 return block_read_full_folio(folio, blkdev_get_block);447}448 449static void blkdev_readahead(struct readahead_control *rac)450{451 mpage_readahead(rac, blkdev_get_block);452}453 454static int blkdev_write_begin(struct file *file, struct address_space *mapping,455 loff_t pos, unsigned len, struct folio **foliop, void **fsdata)456{457 return block_write_begin(mapping, pos, len, foliop, blkdev_get_block);458}459 460static int blkdev_write_end(struct file *file, struct address_space *mapping,461 loff_t pos, unsigned len, unsigned copied, struct folio *folio,462 void *fsdata)463{464 int ret;465 ret = block_write_end(file, mapping, pos, len, copied, folio, fsdata);466 467 folio_unlock(folio);468 folio_put(folio);469 470 return ret;471}472 473const struct address_space_operations def_blk_aops = {474 .dirty_folio = block_dirty_folio,475 .invalidate_folio = block_invalidate_folio,476 .read_folio = blkdev_read_folio,477 .readahead = blkdev_readahead,478 .writepages = blkdev_writepages,479 .write_begin = blkdev_write_begin,480 .write_end = blkdev_write_end,481 .migrate_folio = buffer_migrate_folio_norefs,482 .is_dirty_writeback = buffer_check_dirty_writeback,483};484#else /* CONFIG_BUFFER_HEAD */485static int blkdev_read_folio(struct file *file, struct folio *folio)486{487 return iomap_read_folio(folio, &blkdev_iomap_ops);488}489 490static void blkdev_readahead(struct readahead_control *rac)491{492 iomap_readahead(rac, &blkdev_iomap_ops);493}494 495static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc,496 struct inode *inode, loff_t offset, unsigned int len)497{498 loff_t isize = i_size_read(inode);499 500 if (WARN_ON_ONCE(offset >= isize))501 return -EIO;502 if (offset >= wpc->iomap.offset &&503 offset < wpc->iomap.offset + wpc->iomap.length)504 return 0;505 return blkdev_iomap_begin(inode, offset, isize - offset,506 IOMAP_WRITE, &wpc->iomap, NULL);507}508 509static const struct iomap_writeback_ops blkdev_writeback_ops = {510 .map_blocks = blkdev_map_blocks,511};512 513static int blkdev_writepages(struct address_space *mapping,514 struct writeback_control *wbc)515{516 struct iomap_writepage_ctx wpc = { };517 518 return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops);519}520 521const struct address_space_operations def_blk_aops = {522 .dirty_folio = filemap_dirty_folio,523 .release_folio = iomap_release_folio,524 .invalidate_folio = iomap_invalidate_folio,525 .read_folio = blkdev_read_folio,526 .readahead = blkdev_readahead,527 .writepages = blkdev_writepages,528 .is_partially_uptodate = iomap_is_partially_uptodate,529 .error_remove_folio = generic_error_remove_folio,530 .migrate_folio = filemap_migrate_folio,531};532#endif /* CONFIG_BUFFER_HEAD */533 534/*535 * for a block special file file_inode(file)->i_size is zero536 * so we compute the size by hand (just as in block_read/write above)537 */538static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)539{540 struct inode *bd_inode = bdev_file_inode(file);541 loff_t retval;542 543 inode_lock(bd_inode);544 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));545 inode_unlock(bd_inode);546 return retval;547}548 549static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,550 int datasync)551{552 struct block_device *bdev = I_BDEV(filp->f_mapping->host);553 int error;554 555 error = file_write_and_wait_range(filp, start, end);556 if (error)557 return error;558 559 /*560 * There is no need to serialise calls to blkdev_issue_flush with561 * i_mutex and doing so causes performance issues with concurrent562 * O_SYNC writers to a block device.563 */564 error = blkdev_issue_flush(bdev);565 if (error == -EOPNOTSUPP)566 error = 0;567 568 return error;569}570 571/**572 * file_to_blk_mode - get block open flags from file flags573 * @file: file whose open flags should be converted574 *575 * Look at file open flags and generate corresponding block open flags from576 * them. The function works both for file just being open (e.g. during ->open577 * callback) and for file that is already open. This is actually non-trivial578 * (see comment in the function).579 */580blk_mode_t file_to_blk_mode(struct file *file)581{582 blk_mode_t mode = 0;583 584 if (file->f_mode & FMODE_READ)585 mode |= BLK_OPEN_READ;586 if (file->f_mode & FMODE_WRITE)587 mode |= BLK_OPEN_WRITE;588 /*589 * do_dentry_open() clears O_EXCL from f_flags, use file->private_data590 * to determine whether the open was exclusive for already open files.591 */592 if (file->private_data)593 mode |= BLK_OPEN_EXCL;594 else if (file->f_flags & O_EXCL)595 mode |= BLK_OPEN_EXCL;596 if (file->f_flags & O_NDELAY)597 mode |= BLK_OPEN_NDELAY;598 599 /*600 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy601 * driver has historically allowed ioctls as if the file was opened for602 * writing, but does not allow and actual reads or writes.603 */604 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))605 mode |= BLK_OPEN_WRITE_IOCTL;606 607 return mode;608}609 610static int blkdev_open(struct inode *inode, struct file *filp)611{612 struct block_device *bdev;613 blk_mode_t mode;614 int ret;615 616 mode = file_to_blk_mode(filp);617 /* Use the file as the holder. */618 if (mode & BLK_OPEN_EXCL)619 filp->private_data = filp;620 ret = bdev_permission(inode->i_rdev, mode, filp->private_data);621 if (ret)622 return ret;623 624 bdev = blkdev_get_no_open(inode->i_rdev);625 if (!bdev)626 return -ENXIO;627 628 if (bdev_can_atomic_write(bdev) && filp->f_flags & O_DIRECT)629 filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;630 631 ret = bdev_open(bdev, mode, filp->private_data, NULL, filp);632 if (ret)633 blkdev_put_no_open(bdev);634 return ret;635}636 637static int blkdev_release(struct inode *inode, struct file *filp)638{639 bdev_release(filp);640 return 0;641}642 643static ssize_t644blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)645{646 size_t count = iov_iter_count(from);647 ssize_t written;648 649 written = kiocb_invalidate_pages(iocb, count);650 if (written) {651 if (written == -EBUSY)652 return 0;653 return written;654 }655 656 written = blkdev_direct_IO(iocb, from);657 if (written > 0) {658 kiocb_invalidate_post_direct_write(iocb, count);659 iocb->ki_pos += written;660 count -= written;661 }662 if (written != -EIOCBQUEUED)663 iov_iter_revert(from, count - iov_iter_count(from));664 return written;665}666 667static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)668{669 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL);670}671 672/*673 * Write data to the block device. Only intended for the block device itself674 * and the raw driver which basically is a fake block device.675 *676 * Does not take i_mutex for the write and thus is not for general purpose677 * use.678 */679static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)680{681 struct file *file = iocb->ki_filp;682 struct inode *bd_inode = bdev_file_inode(file);683 struct block_device *bdev = I_BDEV(bd_inode);684 loff_t size = bdev_nr_bytes(bdev);685 size_t shorted = 0;686 ssize_t ret;687 688 if (bdev_read_only(bdev))689 return -EPERM;690 691 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))692 return -ETXTBSY;693 694 if (!iov_iter_count(from))695 return 0;696 697 if (iocb->ki_pos >= size)698 return -ENOSPC;699 700 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)701 return -EOPNOTSUPP;702 703 size -= iocb->ki_pos;704 if (iov_iter_count(from) > size) {705 shorted = iov_iter_count(from) - size;706 iov_iter_truncate(from, size);707 }708 709 ret = file_update_time(file);710 if (ret)711 return ret;712 713 if (iocb->ki_flags & IOCB_DIRECT) {714 ret = blkdev_direct_write(iocb, from);715 if (ret >= 0 && iov_iter_count(from))716 ret = direct_write_fallback(iocb, from, ret,717 blkdev_buffered_write(iocb, from));718 } else {719 ret = blkdev_buffered_write(iocb, from);720 }721 722 if (ret > 0)723 ret = generic_write_sync(iocb, ret);724 iov_iter_reexpand(from, iov_iter_count(from) + shorted);725 return ret;726}727 728static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)729{730 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);731 loff_t size = bdev_nr_bytes(bdev);732 loff_t pos = iocb->ki_pos;733 size_t shorted = 0;734 ssize_t ret = 0;735 size_t count;736 737 if (unlikely(pos + iov_iter_count(to) > size)) {738 if (pos >= size)739 return 0;740 size -= pos;741 shorted = iov_iter_count(to) - size;742 iov_iter_truncate(to, size);743 }744 745 count = iov_iter_count(to);746 if (!count)747 goto reexpand; /* skip atime */748 749 if (iocb->ki_flags & IOCB_DIRECT) {750 ret = kiocb_write_and_wait(iocb, count);751 if (ret < 0)752 goto reexpand;753 file_accessed(iocb->ki_filp);754 755 ret = blkdev_direct_IO(iocb, to);756 if (ret >= 0) {757 iocb->ki_pos += ret;758 count -= ret;759 }760 iov_iter_revert(to, count - iov_iter_count(to));761 if (ret < 0 || !count)762 goto reexpand;763 }764 765 ret = filemap_read(iocb, to, ret);766 767reexpand:768 if (unlikely(shorted))769 iov_iter_reexpand(to, iov_iter_count(to) + shorted);770 return ret;771}772 773#define BLKDEV_FALLOC_FL_SUPPORTED \774 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \775 FALLOC_FL_ZERO_RANGE)776 777static long blkdev_fallocate(struct file *file, int mode, loff_t start,778 loff_t len)779{780 struct inode *inode = bdev_file_inode(file);781 struct block_device *bdev = I_BDEV(inode);782 loff_t end = start + len - 1;783 loff_t isize;784 int error;785 786 /* Fail if we don't recognize the flags. */787 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)788 return -EOPNOTSUPP;789 790 /* Don't go off the end of the device. */791 isize = bdev_nr_bytes(bdev);792 if (start >= isize)793 return -EINVAL;794 if (end >= isize) {795 if (mode & FALLOC_FL_KEEP_SIZE) {796 len = isize - start;797 end = start + len - 1;798 } else799 return -EINVAL;800 }801 802 /*803 * Don't allow IO that isn't aligned to logical block size.804 */805 if ((start | len) & (bdev_logical_block_size(bdev) - 1))806 return -EINVAL;807 808 filemap_invalidate_lock(inode->i_mapping);809 810 /*811 * Invalidate the page cache, including dirty pages, for valid812 * de-allocate mode calls to fallocate().813 */814 switch (mode) {815 case FALLOC_FL_ZERO_RANGE:816 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:817 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);818 if (error)819 goto fail;820 821 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,822 len >> SECTOR_SHIFT, GFP_KERNEL,823 BLKDEV_ZERO_NOUNMAP);824 break;825 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:826 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);827 if (error)828 goto fail;829 830 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,831 len >> SECTOR_SHIFT, GFP_KERNEL,832 BLKDEV_ZERO_NOFALLBACK);833 break;834 default:835 error = -EOPNOTSUPP;836 }837 838 fail:839 filemap_invalidate_unlock(inode->i_mapping);840 return error;841}842 843static int blkdev_mmap(struct file *file, struct vm_area_struct *vma)844{845 struct inode *bd_inode = bdev_file_inode(file);846 847 if (bdev_read_only(I_BDEV(bd_inode)))848 return generic_file_readonly_mmap(file, vma);849 850 return generic_file_mmap(file, vma);851}852 853const struct file_operations def_blk_fops = {854 .open = blkdev_open,855 .release = blkdev_release,856 .llseek = blkdev_llseek,857 .read_iter = blkdev_read_iter,858 .write_iter = blkdev_write_iter,859 .iopoll = iocb_bio_iopoll,860 .mmap = blkdev_mmap,861 .fsync = blkdev_fsync,862 .unlocked_ioctl = blkdev_ioctl,863#ifdef CONFIG_COMPAT864 .compat_ioctl = compat_blkdev_ioctl,865#endif866 .splice_read = filemap_splice_read,867 .splice_write = iter_file_splice_write,868 .fallocate = blkdev_fallocate,869 .uring_cmd = blkdev_uring_cmd,870 .fop_flags = FOP_BUFFER_RASYNC,871};872 873static __init int blkdev_init(void)874{875 return bioset_init(&blkdev_dio_pool, 4,876 offsetof(struct blkdev_dio, bio),877 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);878}879module_init(blkdev_init);880