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-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCaINCgQAKCRCRxhvAZXjc os+nAP9LFHUwWO6EBzHJJGEVjJvvzsbzqeYrRFamYiMc5ulPJwD+KW4RIgJa/MWO pcYE40CacaekD8rFWwYUyszpgmv6ewc= =wCwp -----END PGP SIGNATURE----- Merge tag 'vfs-6.17-rc1.mmap_prepare' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull mmap_prepare updates from Christian Brauner: "Last cycle we introduce f_op->mmap_prepare() inc84bf6dd2b
("mm: introduce new .mmap_prepare() file callback"). This is preferred to the existing f_op->mmap() hook as it does require a VMA to be established yet, thus allowing the mmap logic to invoke this hook far, far earlier, prior to inserting a VMA into the virtual address space, or performing any other heavy handed operations. This allows for much simpler unwinding on error, and for there to be a single attempt at merging a VMA rather than having to possibly reattempt a merge based on potentially altered VMA state. Far more importantly, it prevents inappropriate manipulation of incompletely initialised VMA state, which is something that has been the cause of bugs and complexity in the past. The intent is to gradually deprecate f_op->mmap, and in that vein this series coverts the majority of file systems to using f_op->mmap_prepare. Prerequisite steps are taken - firstly ensuring all checks for mmap capabilities use the file_has_valid_mmap_hooks() helper rather than directly checking for f_op->mmap (which is now not a valid check) and secondly updating daxdev_mapping_supported() to not require a VMA parameter to allow ext4 and xfs to be converted. Commitbb666b7c27
("mm: add mmap_prepare() compatibility layer for nested file systems") handles the nasty edge-case of nested file systems like overlayfs, which introduces a compatibility shim to allow f_op->mmap_prepare() to be invoked from an f_op->mmap() callback. This allows for nested filesystems to continue to function correctly with all file systems regardless of which callback is used. Once we finally convert all file systems, this shim can be removed. As a result, ecryptfs, fuse, and overlayfs remain unaltered so they can nest all other file systems. We additionally do not update resctl - as this requires an update to remap_pfn_range() (or an alternative to it) which we defer to a later series, equally we do not update cramfs which needs a mixed mapping insertion with the same issue, nor do we update procfs, hugetlbfs, syfs or kernfs all of which require VMAs for internal state and hooks. We shall return to all of these later" * tag 'vfs-6.17-rc1.mmap_prepare' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: doc: update porting, vfs documentation to describe mmap_prepare() fs: replace mmap hook with .mmap_prepare for simple mappings fs: convert most other generic_file_*mmap() users to .mmap_prepare() fs: convert simple use of generic_file_*_mmap() to .mmap_prepare() mm/filemap: introduce generic_file_*_mmap_prepare() helpers fs/xfs: transition from deprecated .mmap hook to .mmap_prepare fs/ext4: transition from deprecated .mmap hook to .mmap_prepare fs/dax: make it possible to check dev dax support without a VMA fs: consistently use can_mmap_file() helper mm/nommu: use file_has_valid_mmap_hooks() helper mm: rename call_mmap/mmap_prepare to vfs_mmap/mmap_prepare
959 lines
24 KiB
C
959 lines
24 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
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* Copyright (C) 2016 - 2020 Christoph Hellwig
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*/
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/blkdev.h>
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#include <linux/buffer_head.h>
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#include <linux/mpage.h>
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#include <linux/uio.h>
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#include <linux/namei.h>
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#include <linux/task_io_accounting_ops.h>
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#include <linux/falloc.h>
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#include <linux/suspend.h>
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#include <linux/fs.h>
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#include <linux/iomap.h>
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#include <linux/module.h>
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#include <linux/io_uring/cmd.h>
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#include "blk.h"
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static inline struct inode *bdev_file_inode(struct file *file)
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{
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return file->f_mapping->host;
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}
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static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
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{
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blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
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/* avoid the need for a I/O completion work item */
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if (iocb_is_dsync(iocb))
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opf |= REQ_FUA;
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return opf;
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}
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static bool blkdev_dio_invalid(struct block_device *bdev, struct kiocb *iocb,
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struct iov_iter *iter)
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{
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return iocb->ki_pos & (bdev_logical_block_size(bdev) - 1) ||
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!bdev_iter_is_aligned(bdev, iter);
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}
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#define DIO_INLINE_BIO_VECS 4
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static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
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struct iov_iter *iter, struct block_device *bdev,
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unsigned int nr_pages)
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{
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struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
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loff_t pos = iocb->ki_pos;
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bool should_dirty = false;
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struct bio bio;
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ssize_t ret;
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WARN_ON_ONCE(iocb->ki_flags & IOCB_HAS_METADATA);
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if (nr_pages <= DIO_INLINE_BIO_VECS)
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vecs = inline_vecs;
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else {
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vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),
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GFP_KERNEL);
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if (!vecs)
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return -ENOMEM;
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}
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if (iov_iter_rw(iter) == READ) {
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bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
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if (user_backed_iter(iter))
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should_dirty = true;
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} else {
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bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
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}
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bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
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bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
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bio.bi_write_stream = iocb->ki_write_stream;
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bio.bi_ioprio = iocb->ki_ioprio;
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if (iocb->ki_flags & IOCB_ATOMIC)
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bio.bi_opf |= REQ_ATOMIC;
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ret = bio_iov_iter_get_pages(&bio, iter);
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if (unlikely(ret))
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goto out;
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ret = bio.bi_iter.bi_size;
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if (iov_iter_rw(iter) == WRITE)
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task_io_account_write(ret);
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if (iocb->ki_flags & IOCB_NOWAIT)
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bio.bi_opf |= REQ_NOWAIT;
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submit_bio_wait(&bio);
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bio_release_pages(&bio, should_dirty);
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if (unlikely(bio.bi_status))
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ret = blk_status_to_errno(bio.bi_status);
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out:
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if (vecs != inline_vecs)
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kfree(vecs);
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bio_uninit(&bio);
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return ret;
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}
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enum {
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DIO_SHOULD_DIRTY = 1,
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DIO_IS_SYNC = 2,
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};
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struct blkdev_dio {
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union {
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struct kiocb *iocb;
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struct task_struct *waiter;
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};
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size_t size;
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atomic_t ref;
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unsigned int flags;
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struct bio bio ____cacheline_aligned_in_smp;
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};
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static struct bio_set blkdev_dio_pool;
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static void blkdev_bio_end_io(struct bio *bio)
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{
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struct blkdev_dio *dio = bio->bi_private;
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bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
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bool is_sync = dio->flags & DIO_IS_SYNC;
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if (bio->bi_status && !dio->bio.bi_status)
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dio->bio.bi_status = bio->bi_status;
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if (!is_sync && (dio->iocb->ki_flags & IOCB_HAS_METADATA))
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bio_integrity_unmap_user(bio);
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if (atomic_dec_and_test(&dio->ref)) {
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if (!is_sync) {
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struct kiocb *iocb = dio->iocb;
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ssize_t ret;
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WRITE_ONCE(iocb->private, NULL);
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if (likely(!dio->bio.bi_status)) {
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ret = dio->size;
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iocb->ki_pos += ret;
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} else {
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ret = blk_status_to_errno(dio->bio.bi_status);
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}
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dio->iocb->ki_complete(iocb, ret);
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bio_put(&dio->bio);
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} else {
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struct task_struct *waiter = dio->waiter;
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WRITE_ONCE(dio->waiter, NULL);
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blk_wake_io_task(waiter);
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}
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}
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if (should_dirty) {
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bio_check_pages_dirty(bio);
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} else {
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bio_release_pages(bio, false);
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bio_put(bio);
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}
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}
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static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
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struct block_device *bdev, unsigned int nr_pages)
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{
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struct blk_plug plug;
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struct blkdev_dio *dio;
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struct bio *bio;
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bool is_read = (iov_iter_rw(iter) == READ), is_sync;
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blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
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loff_t pos = iocb->ki_pos;
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int ret = 0;
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if (iocb->ki_flags & IOCB_ALLOC_CACHE)
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opf |= REQ_ALLOC_CACHE;
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bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
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&blkdev_dio_pool);
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dio = container_of(bio, struct blkdev_dio, bio);
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atomic_set(&dio->ref, 1);
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/*
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* Grab an extra reference to ensure the dio structure which is embedded
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* into the first bio stays around.
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*/
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bio_get(bio);
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is_sync = is_sync_kiocb(iocb);
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if (is_sync) {
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dio->flags = DIO_IS_SYNC;
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dio->waiter = current;
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} else {
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dio->flags = 0;
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dio->iocb = iocb;
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}
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dio->size = 0;
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if (is_read && user_backed_iter(iter))
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dio->flags |= DIO_SHOULD_DIRTY;
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blk_start_plug(&plug);
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for (;;) {
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bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
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bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
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bio->bi_write_stream = iocb->ki_write_stream;
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bio->bi_private = dio;
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bio->bi_end_io = blkdev_bio_end_io;
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bio->bi_ioprio = iocb->ki_ioprio;
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ret = bio_iov_iter_get_pages(bio, iter);
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if (unlikely(ret)) {
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bio->bi_status = BLK_STS_IOERR;
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bio_endio(bio);
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break;
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}
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if (iocb->ki_flags & IOCB_NOWAIT) {
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/*
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* This is nonblocking IO, and we need to allocate
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* another bio if we have data left to map. As we
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* cannot guarantee that one of the sub bios will not
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* fail getting issued FOR NOWAIT and as error results
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* are coalesced across all of them, be safe and ask for
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* a retry of this from blocking context.
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*/
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if (unlikely(iov_iter_count(iter))) {
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ret = -EAGAIN;
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goto fail;
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}
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bio->bi_opf |= REQ_NOWAIT;
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}
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if (!is_sync && (iocb->ki_flags & IOCB_HAS_METADATA)) {
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ret = bio_integrity_map_iter(bio, iocb->private);
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if (unlikely(ret))
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goto fail;
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}
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if (is_read) {
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if (dio->flags & DIO_SHOULD_DIRTY)
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bio_set_pages_dirty(bio);
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} else {
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task_io_account_write(bio->bi_iter.bi_size);
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}
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dio->size += bio->bi_iter.bi_size;
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pos += bio->bi_iter.bi_size;
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nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
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if (!nr_pages) {
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submit_bio(bio);
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break;
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}
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atomic_inc(&dio->ref);
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submit_bio(bio);
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bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
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}
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blk_finish_plug(&plug);
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if (!is_sync)
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return -EIOCBQUEUED;
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for (;;) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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if (!READ_ONCE(dio->waiter))
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break;
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blk_io_schedule();
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}
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__set_current_state(TASK_RUNNING);
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if (!ret)
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ret = blk_status_to_errno(dio->bio.bi_status);
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if (likely(!ret))
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ret = dio->size;
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bio_put(&dio->bio);
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return ret;
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fail:
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bio_release_pages(bio, false);
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bio_clear_flag(bio, BIO_REFFED);
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bio_put(bio);
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blk_finish_plug(&plug);
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return ret;
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}
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static void blkdev_bio_end_io_async(struct bio *bio)
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{
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struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
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struct kiocb *iocb = dio->iocb;
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ssize_t ret;
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WRITE_ONCE(iocb->private, NULL);
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if (likely(!bio->bi_status)) {
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ret = dio->size;
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iocb->ki_pos += ret;
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} else {
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ret = blk_status_to_errno(bio->bi_status);
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}
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if (iocb->ki_flags & IOCB_HAS_METADATA)
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bio_integrity_unmap_user(bio);
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iocb->ki_complete(iocb, ret);
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if (dio->flags & DIO_SHOULD_DIRTY) {
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bio_check_pages_dirty(bio);
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} else {
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bio_release_pages(bio, false);
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bio_put(bio);
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}
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}
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static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
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struct iov_iter *iter,
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struct block_device *bdev,
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unsigned int nr_pages)
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{
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bool is_read = iov_iter_rw(iter) == READ;
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blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
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struct blkdev_dio *dio;
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struct bio *bio;
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loff_t pos = iocb->ki_pos;
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int ret = 0;
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if (iocb->ki_flags & IOCB_ALLOC_CACHE)
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opf |= REQ_ALLOC_CACHE;
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bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
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&blkdev_dio_pool);
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dio = container_of(bio, struct blkdev_dio, bio);
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dio->flags = 0;
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dio->iocb = iocb;
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bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
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bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
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bio->bi_write_stream = iocb->ki_write_stream;
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bio->bi_end_io = blkdev_bio_end_io_async;
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bio->bi_ioprio = iocb->ki_ioprio;
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if (iov_iter_is_bvec(iter)) {
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/*
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* Users don't rely on the iterator being in any particular
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* state for async I/O returning -EIOCBQUEUED, hence we can
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* avoid expensive iov_iter_advance(). Bypass
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* bio_iov_iter_get_pages() and set the bvec directly.
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*/
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bio_iov_bvec_set(bio, iter);
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} else {
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ret = bio_iov_iter_get_pages(bio, iter);
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if (unlikely(ret))
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goto out_bio_put;
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}
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dio->size = bio->bi_iter.bi_size;
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if (is_read) {
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if (user_backed_iter(iter)) {
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dio->flags |= DIO_SHOULD_DIRTY;
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bio_set_pages_dirty(bio);
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}
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} else {
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task_io_account_write(bio->bi_iter.bi_size);
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}
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if (iocb->ki_flags & IOCB_HAS_METADATA) {
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ret = bio_integrity_map_iter(bio, iocb->private);
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WRITE_ONCE(iocb->private, NULL);
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if (unlikely(ret))
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goto out_bio_put;
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}
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if (iocb->ki_flags & IOCB_ATOMIC)
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bio->bi_opf |= REQ_ATOMIC;
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if (iocb->ki_flags & IOCB_NOWAIT)
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bio->bi_opf |= REQ_NOWAIT;
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if (iocb->ki_flags & IOCB_HIPRI) {
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bio->bi_opf |= REQ_POLLED;
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submit_bio(bio);
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WRITE_ONCE(iocb->private, bio);
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} else {
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submit_bio(bio);
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}
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return -EIOCBQUEUED;
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out_bio_put:
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bio_put(bio);
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return ret;
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}
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static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
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{
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struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
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unsigned int nr_pages;
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if (!iov_iter_count(iter))
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return 0;
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if (blkdev_dio_invalid(bdev, iocb, iter))
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return -EINVAL;
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if (iov_iter_rw(iter) == WRITE) {
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u16 max_write_streams = bdev_max_write_streams(bdev);
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if (iocb->ki_write_stream) {
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if (iocb->ki_write_stream > max_write_streams)
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return -EINVAL;
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} else if (max_write_streams) {
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enum rw_hint write_hint =
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file_inode(iocb->ki_filp)->i_write_hint;
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/*
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* Just use the write hint as write stream for block
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* device writes. This assumes no file system is
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* mounted that would use the streams differently.
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*/
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if (write_hint <= max_write_streams)
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iocb->ki_write_stream = write_hint;
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}
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}
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nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
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if (likely(nr_pages <= BIO_MAX_VECS)) {
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if (is_sync_kiocb(iocb))
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return __blkdev_direct_IO_simple(iocb, iter, bdev,
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nr_pages);
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return __blkdev_direct_IO_async(iocb, iter, bdev, nr_pages);
|
|
} else if (iocb->ki_flags & IOCB_ATOMIC) {
|
|
return -EINVAL;
|
|
}
|
|
return __blkdev_direct_IO(iocb, iter, bdev, bio_max_segs(nr_pages));
|
|
}
|
|
|
|
static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
|
|
unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
|
|
{
|
|
struct block_device *bdev = I_BDEV(inode);
|
|
loff_t isize = i_size_read(inode);
|
|
|
|
if (offset >= isize)
|
|
return -EIO;
|
|
|
|
iomap->bdev = bdev;
|
|
iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
|
|
iomap->type = IOMAP_MAPPED;
|
|
iomap->addr = iomap->offset;
|
|
iomap->length = isize - iomap->offset;
|
|
iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
|
|
return 0;
|
|
}
|
|
|
|
static const struct iomap_ops blkdev_iomap_ops = {
|
|
.iomap_begin = blkdev_iomap_begin,
|
|
};
|
|
|
|
#ifdef CONFIG_BUFFER_HEAD
|
|
static int blkdev_get_block(struct inode *inode, sector_t iblock,
|
|
struct buffer_head *bh, int create)
|
|
{
|
|
bh->b_bdev = I_BDEV(inode);
|
|
bh->b_blocknr = iblock;
|
|
set_buffer_mapped(bh);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* We cannot call mpage_writepages() as it does not take the buffer lock.
|
|
* We must use block_write_full_folio() directly which holds the buffer
|
|
* lock. The buffer lock provides the synchronisation with writeback
|
|
* that filesystems rely on when they use the blockdev's mapping.
|
|
*/
|
|
static int blkdev_writepages(struct address_space *mapping,
|
|
struct writeback_control *wbc)
|
|
{
|
|
struct folio *folio = NULL;
|
|
struct blk_plug plug;
|
|
int err;
|
|
|
|
blk_start_plug(&plug);
|
|
while ((folio = writeback_iter(mapping, wbc, folio, &err)))
|
|
err = block_write_full_folio(folio, wbc, blkdev_get_block);
|
|
blk_finish_plug(&plug);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int blkdev_read_folio(struct file *file, struct folio *folio)
|
|
{
|
|
return block_read_full_folio(folio, blkdev_get_block);
|
|
}
|
|
|
|
static void blkdev_readahead(struct readahead_control *rac)
|
|
{
|
|
mpage_readahead(rac, blkdev_get_block);
|
|
}
|
|
|
|
static int blkdev_write_begin(const struct kiocb *iocb,
|
|
struct address_space *mapping, loff_t pos,
|
|
unsigned len, struct folio **foliop,
|
|
void **fsdata)
|
|
{
|
|
return block_write_begin(mapping, pos, len, foliop, blkdev_get_block);
|
|
}
|
|
|
|
static int blkdev_write_end(const struct kiocb *iocb,
|
|
struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct folio *folio, void *fsdata)
|
|
{
|
|
int ret;
|
|
ret = block_write_end(pos, len, copied, folio);
|
|
|
|
folio_unlock(folio);
|
|
folio_put(folio);
|
|
|
|
return ret;
|
|
}
|
|
|
|
const struct address_space_operations def_blk_aops = {
|
|
.dirty_folio = block_dirty_folio,
|
|
.invalidate_folio = block_invalidate_folio,
|
|
.read_folio = blkdev_read_folio,
|
|
.readahead = blkdev_readahead,
|
|
.writepages = blkdev_writepages,
|
|
.write_begin = blkdev_write_begin,
|
|
.write_end = blkdev_write_end,
|
|
.migrate_folio = buffer_migrate_folio_norefs,
|
|
.is_dirty_writeback = buffer_check_dirty_writeback,
|
|
};
|
|
#else /* CONFIG_BUFFER_HEAD */
|
|
static int blkdev_read_folio(struct file *file, struct folio *folio)
|
|
{
|
|
return iomap_read_folio(folio, &blkdev_iomap_ops);
|
|
}
|
|
|
|
static void blkdev_readahead(struct readahead_control *rac)
|
|
{
|
|
iomap_readahead(rac, &blkdev_iomap_ops);
|
|
}
|
|
|
|
static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc,
|
|
struct inode *inode, loff_t offset, unsigned int len)
|
|
{
|
|
loff_t isize = i_size_read(inode);
|
|
|
|
if (WARN_ON_ONCE(offset >= isize))
|
|
return -EIO;
|
|
if (offset >= wpc->iomap.offset &&
|
|
offset < wpc->iomap.offset + wpc->iomap.length)
|
|
return 0;
|
|
return blkdev_iomap_begin(inode, offset, isize - offset,
|
|
IOMAP_WRITE, &wpc->iomap, NULL);
|
|
}
|
|
|
|
static const struct iomap_writeback_ops blkdev_writeback_ops = {
|
|
.map_blocks = blkdev_map_blocks,
|
|
};
|
|
|
|
static int blkdev_writepages(struct address_space *mapping,
|
|
struct writeback_control *wbc)
|
|
{
|
|
struct iomap_writepage_ctx wpc = { };
|
|
|
|
return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops);
|
|
}
|
|
|
|
const struct address_space_operations def_blk_aops = {
|
|
.dirty_folio = filemap_dirty_folio,
|
|
.release_folio = iomap_release_folio,
|
|
.invalidate_folio = iomap_invalidate_folio,
|
|
.read_folio = blkdev_read_folio,
|
|
.readahead = blkdev_readahead,
|
|
.writepages = blkdev_writepages,
|
|
.is_partially_uptodate = iomap_is_partially_uptodate,
|
|
.error_remove_folio = generic_error_remove_folio,
|
|
.migrate_folio = filemap_migrate_folio,
|
|
};
|
|
#endif /* CONFIG_BUFFER_HEAD */
|
|
|
|
/*
|
|
* for a block special file file_inode(file)->i_size is zero
|
|
* so we compute the size by hand (just as in block_read/write above)
|
|
*/
|
|
static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
|
|
{
|
|
struct inode *bd_inode = bdev_file_inode(file);
|
|
loff_t retval;
|
|
|
|
inode_lock(bd_inode);
|
|
retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
|
|
inode_unlock(bd_inode);
|
|
return retval;
|
|
}
|
|
|
|
static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
|
|
int datasync)
|
|
{
|
|
struct block_device *bdev = I_BDEV(filp->f_mapping->host);
|
|
int error;
|
|
|
|
error = file_write_and_wait_range(filp, start, end);
|
|
if (error)
|
|
return error;
|
|
|
|
/*
|
|
* There is no need to serialise calls to blkdev_issue_flush with
|
|
* i_mutex and doing so causes performance issues with concurrent
|
|
* O_SYNC writers to a block device.
|
|
*/
|
|
error = blkdev_issue_flush(bdev);
|
|
if (error == -EOPNOTSUPP)
|
|
error = 0;
|
|
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* file_to_blk_mode - get block open flags from file flags
|
|
* @file: file whose open flags should be converted
|
|
*
|
|
* Look at file open flags and generate corresponding block open flags from
|
|
* them. The function works both for file just being open (e.g. during ->open
|
|
* callback) and for file that is already open. This is actually non-trivial
|
|
* (see comment in the function).
|
|
*/
|
|
blk_mode_t file_to_blk_mode(struct file *file)
|
|
{
|
|
blk_mode_t mode = 0;
|
|
|
|
if (file->f_mode & FMODE_READ)
|
|
mode |= BLK_OPEN_READ;
|
|
if (file->f_mode & FMODE_WRITE)
|
|
mode |= BLK_OPEN_WRITE;
|
|
/*
|
|
* do_dentry_open() clears O_EXCL from f_flags, use file->private_data
|
|
* to determine whether the open was exclusive for already open files.
|
|
*/
|
|
if (file->private_data)
|
|
mode |= BLK_OPEN_EXCL;
|
|
else if (file->f_flags & O_EXCL)
|
|
mode |= BLK_OPEN_EXCL;
|
|
if (file->f_flags & O_NDELAY)
|
|
mode |= BLK_OPEN_NDELAY;
|
|
|
|
/*
|
|
* If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
|
|
* driver has historically allowed ioctls as if the file was opened for
|
|
* writing, but does not allow and actual reads or writes.
|
|
*/
|
|
if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
|
|
mode |= BLK_OPEN_WRITE_IOCTL;
|
|
|
|
return mode;
|
|
}
|
|
|
|
static int blkdev_open(struct inode *inode, struct file *filp)
|
|
{
|
|
struct block_device *bdev;
|
|
blk_mode_t mode;
|
|
int ret;
|
|
|
|
mode = file_to_blk_mode(filp);
|
|
/* Use the file as the holder. */
|
|
if (mode & BLK_OPEN_EXCL)
|
|
filp->private_data = filp;
|
|
ret = bdev_permission(inode->i_rdev, mode, filp->private_data);
|
|
if (ret)
|
|
return ret;
|
|
|
|
bdev = blkdev_get_no_open(inode->i_rdev, true);
|
|
if (!bdev)
|
|
return -ENXIO;
|
|
|
|
if (bdev_can_atomic_write(bdev))
|
|
filp->f_mode |= FMODE_CAN_ATOMIC_WRITE;
|
|
|
|
ret = bdev_open(bdev, mode, filp->private_data, NULL, filp);
|
|
if (ret)
|
|
blkdev_put_no_open(bdev);
|
|
return ret;
|
|
}
|
|
|
|
static int blkdev_release(struct inode *inode, struct file *filp)
|
|
{
|
|
bdev_release(filp);
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t
|
|
blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
|
|
{
|
|
size_t count = iov_iter_count(from);
|
|
ssize_t written;
|
|
|
|
written = kiocb_invalidate_pages(iocb, count);
|
|
if (written) {
|
|
if (written == -EBUSY)
|
|
return 0;
|
|
return written;
|
|
}
|
|
|
|
written = blkdev_direct_IO(iocb, from);
|
|
if (written > 0) {
|
|
kiocb_invalidate_post_direct_write(iocb, count);
|
|
iocb->ki_pos += written;
|
|
count -= written;
|
|
}
|
|
if (written != -EIOCBQUEUED)
|
|
iov_iter_revert(from, count - iov_iter_count(from));
|
|
return written;
|
|
}
|
|
|
|
static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
|
|
{
|
|
return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops, NULL);
|
|
}
|
|
|
|
/*
|
|
* Write data to the block device. Only intended for the block device itself
|
|
* and the raw driver which basically is a fake block device.
|
|
*
|
|
* Does not take i_mutex for the write and thus is not for general purpose
|
|
* use.
|
|
*/
|
|
static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
struct inode *bd_inode = bdev_file_inode(file);
|
|
struct block_device *bdev = I_BDEV(bd_inode);
|
|
bool atomic = iocb->ki_flags & IOCB_ATOMIC;
|
|
loff_t size = bdev_nr_bytes(bdev);
|
|
size_t shorted = 0;
|
|
ssize_t ret;
|
|
|
|
if (bdev_read_only(bdev))
|
|
return -EPERM;
|
|
|
|
if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
|
|
return -ETXTBSY;
|
|
|
|
if (!iov_iter_count(from))
|
|
return 0;
|
|
|
|
if (iocb->ki_pos >= size)
|
|
return -ENOSPC;
|
|
|
|
if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
|
|
return -EOPNOTSUPP;
|
|
|
|
if (atomic) {
|
|
ret = generic_atomic_write_valid(iocb, from);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
size -= iocb->ki_pos;
|
|
if (iov_iter_count(from) > size) {
|
|
if (atomic)
|
|
return -EINVAL;
|
|
shorted = iov_iter_count(from) - size;
|
|
iov_iter_truncate(from, size);
|
|
}
|
|
|
|
ret = file_update_time(file);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (iocb->ki_flags & IOCB_DIRECT) {
|
|
ret = blkdev_direct_write(iocb, from);
|
|
if (ret >= 0 && iov_iter_count(from))
|
|
ret = direct_write_fallback(iocb, from, ret,
|
|
blkdev_buffered_write(iocb, from));
|
|
} else {
|
|
/*
|
|
* Take i_rwsem and invalidate_lock to avoid racing with
|
|
* set_blocksize changing i_blkbits/folio order and punching
|
|
* out the pagecache.
|
|
*/
|
|
inode_lock_shared(bd_inode);
|
|
ret = blkdev_buffered_write(iocb, from);
|
|
inode_unlock_shared(bd_inode);
|
|
}
|
|
|
|
if (ret > 0)
|
|
ret = generic_write_sync(iocb, ret);
|
|
iov_iter_reexpand(from, iov_iter_count(from) + shorted);
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
|
|
{
|
|
struct inode *bd_inode = bdev_file_inode(iocb->ki_filp);
|
|
struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
|
|
loff_t size = bdev_nr_bytes(bdev);
|
|
loff_t pos = iocb->ki_pos;
|
|
size_t shorted = 0;
|
|
ssize_t ret = 0;
|
|
size_t count;
|
|
|
|
if (unlikely(pos + iov_iter_count(to) > size)) {
|
|
if (pos >= size)
|
|
return 0;
|
|
size -= pos;
|
|
shorted = iov_iter_count(to) - size;
|
|
iov_iter_truncate(to, size);
|
|
}
|
|
|
|
count = iov_iter_count(to);
|
|
if (!count)
|
|
goto reexpand; /* skip atime */
|
|
|
|
if (iocb->ki_flags & IOCB_DIRECT) {
|
|
ret = kiocb_write_and_wait(iocb, count);
|
|
if (ret < 0)
|
|
goto reexpand;
|
|
file_accessed(iocb->ki_filp);
|
|
|
|
ret = blkdev_direct_IO(iocb, to);
|
|
if (ret > 0) {
|
|
iocb->ki_pos += ret;
|
|
count -= ret;
|
|
}
|
|
if (ret != -EIOCBQUEUED)
|
|
iov_iter_revert(to, count - iov_iter_count(to));
|
|
if (ret < 0 || !count)
|
|
goto reexpand;
|
|
}
|
|
|
|
/*
|
|
* Take i_rwsem and invalidate_lock to avoid racing with set_blocksize
|
|
* changing i_blkbits/folio order and punching out the pagecache.
|
|
*/
|
|
inode_lock_shared(bd_inode);
|
|
ret = filemap_read(iocb, to, ret);
|
|
inode_unlock_shared(bd_inode);
|
|
|
|
reexpand:
|
|
if (unlikely(shorted))
|
|
iov_iter_reexpand(to, iov_iter_count(to) + shorted);
|
|
return ret;
|
|
}
|
|
|
|
#define BLKDEV_FALLOC_FL_SUPPORTED \
|
|
(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
|
|
FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES)
|
|
|
|
static long blkdev_fallocate(struct file *file, int mode, loff_t start,
|
|
loff_t len)
|
|
{
|
|
struct inode *inode = bdev_file_inode(file);
|
|
struct block_device *bdev = I_BDEV(inode);
|
|
loff_t end = start + len - 1;
|
|
loff_t isize;
|
|
unsigned int flags;
|
|
int error;
|
|
|
|
/* Fail if we don't recognize the flags. */
|
|
if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
|
|
return -EOPNOTSUPP;
|
|
/*
|
|
* Don't allow writing zeroes if the device does not enable the
|
|
* unmap write zeroes operation.
|
|
*/
|
|
if ((mode & FALLOC_FL_WRITE_ZEROES) &&
|
|
!bdev_write_zeroes_unmap_sectors(bdev))
|
|
return -EOPNOTSUPP;
|
|
|
|
/* Don't go off the end of the device. */
|
|
isize = bdev_nr_bytes(bdev);
|
|
if (start >= isize)
|
|
return -EINVAL;
|
|
if (end >= isize) {
|
|
if (mode & FALLOC_FL_KEEP_SIZE) {
|
|
len = isize - start;
|
|
end = start + len - 1;
|
|
} else
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* Don't allow IO that isn't aligned to logical block size.
|
|
*/
|
|
if ((start | len) & (bdev_logical_block_size(bdev) - 1))
|
|
return -EINVAL;
|
|
|
|
inode_lock(inode);
|
|
filemap_invalidate_lock(inode->i_mapping);
|
|
|
|
switch (mode) {
|
|
case FALLOC_FL_ZERO_RANGE:
|
|
case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
|
|
flags = BLKDEV_ZERO_NOUNMAP;
|
|
break;
|
|
case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
|
|
flags = BLKDEV_ZERO_NOFALLBACK;
|
|
break;
|
|
case FALLOC_FL_WRITE_ZEROES:
|
|
flags = 0;
|
|
break;
|
|
default:
|
|
error = -EOPNOTSUPP;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* Invalidate the page cache, including dirty pages, for valid
|
|
* de-allocate mode calls to fallocate().
|
|
*/
|
|
error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
|
|
if (error)
|
|
goto fail;
|
|
|
|
error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
|
|
len >> SECTOR_SHIFT, GFP_KERNEL, flags);
|
|
fail:
|
|
filemap_invalidate_unlock(inode->i_mapping);
|
|
inode_unlock(inode);
|
|
return error;
|
|
}
|
|
|
|
static int blkdev_mmap_prepare(struct vm_area_desc *desc)
|
|
{
|
|
struct file *file = desc->file;
|
|
|
|
if (bdev_read_only(I_BDEV(bdev_file_inode(file))))
|
|
return generic_file_readonly_mmap_prepare(desc);
|
|
|
|
return generic_file_mmap_prepare(desc);
|
|
}
|
|
|
|
const struct file_operations def_blk_fops = {
|
|
.open = blkdev_open,
|
|
.release = blkdev_release,
|
|
.llseek = blkdev_llseek,
|
|
.read_iter = blkdev_read_iter,
|
|
.write_iter = blkdev_write_iter,
|
|
.iopoll = iocb_bio_iopoll,
|
|
.mmap_prepare = blkdev_mmap_prepare,
|
|
.fsync = blkdev_fsync,
|
|
.unlocked_ioctl = blkdev_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = compat_blkdev_ioctl,
|
|
#endif
|
|
.splice_read = filemap_splice_read,
|
|
.splice_write = iter_file_splice_write,
|
|
.fallocate = blkdev_fallocate,
|
|
.uring_cmd = blkdev_uring_cmd,
|
|
.fop_flags = FOP_BUFFER_RASYNC,
|
|
};
|
|
|
|
static __init int blkdev_init(void)
|
|
{
|
|
return bioset_init(&blkdev_dio_pool, 4,
|
|
offsetof(struct blkdev_dio, bio),
|
|
BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
|
|
}
|
|
module_init(blkdev_init);
|