forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
696 lines
19 KiB
696 lines
19 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Copyright (C) 2010 Red Hat, Inc. |
|
* Copyright (c) 2016-2021 Christoph Hellwig. |
|
*/ |
|
#include <linux/module.h> |
|
#include <linux/compiler.h> |
|
#include <linux/fs.h> |
|
#include <linux/fscrypt.h> |
|
#include <linux/pagemap.h> |
|
#include <linux/iomap.h> |
|
#include <linux/backing-dev.h> |
|
#include <linux/uio.h> |
|
#include <linux/task_io_accounting_ops.h> |
|
#include "trace.h" |
|
|
|
#include "../internal.h" |
|
|
|
/* |
|
* Private flags for iomap_dio, must not overlap with the public ones in |
|
* iomap.h: |
|
*/ |
|
#define IOMAP_DIO_WRITE_FUA (1 << 28) |
|
#define IOMAP_DIO_NEED_SYNC (1 << 29) |
|
#define IOMAP_DIO_WRITE (1 << 30) |
|
#define IOMAP_DIO_DIRTY (1 << 31) |
|
|
|
struct iomap_dio { |
|
struct kiocb *iocb; |
|
const struct iomap_dio_ops *dops; |
|
loff_t i_size; |
|
loff_t size; |
|
atomic_t ref; |
|
unsigned flags; |
|
int error; |
|
size_t done_before; |
|
bool wait_for_completion; |
|
|
|
union { |
|
/* used during submission and for synchronous completion: */ |
|
struct { |
|
struct iov_iter *iter; |
|
struct task_struct *waiter; |
|
struct bio *poll_bio; |
|
} submit; |
|
|
|
/* used for aio completion: */ |
|
struct { |
|
struct work_struct work; |
|
} aio; |
|
}; |
|
}; |
|
|
|
static struct bio *iomap_dio_alloc_bio(const struct iomap_iter *iter, |
|
struct iomap_dio *dio, unsigned short nr_vecs, blk_opf_t opf) |
|
{ |
|
if (dio->dops && dio->dops->bio_set) |
|
return bio_alloc_bioset(iter->iomap.bdev, nr_vecs, opf, |
|
GFP_KERNEL, dio->dops->bio_set); |
|
return bio_alloc(iter->iomap.bdev, nr_vecs, opf, GFP_KERNEL); |
|
} |
|
|
|
static void iomap_dio_submit_bio(const struct iomap_iter *iter, |
|
struct iomap_dio *dio, struct bio *bio, loff_t pos) |
|
{ |
|
atomic_inc(&dio->ref); |
|
|
|
/* Sync dio can't be polled reliably */ |
|
if ((dio->iocb->ki_flags & IOCB_HIPRI) && !is_sync_kiocb(dio->iocb)) { |
|
bio_set_polled(bio, dio->iocb); |
|
dio->submit.poll_bio = bio; |
|
} |
|
|
|
if (dio->dops && dio->dops->submit_io) |
|
dio->dops->submit_io(iter, bio, pos); |
|
else |
|
submit_bio(bio); |
|
} |
|
|
|
ssize_t iomap_dio_complete(struct iomap_dio *dio) |
|
{ |
|
const struct iomap_dio_ops *dops = dio->dops; |
|
struct kiocb *iocb = dio->iocb; |
|
struct inode *inode = file_inode(iocb->ki_filp); |
|
loff_t offset = iocb->ki_pos; |
|
ssize_t ret = dio->error; |
|
|
|
if (dops && dops->end_io) |
|
ret = dops->end_io(iocb, dio->size, ret, dio->flags); |
|
|
|
if (likely(!ret)) { |
|
ret = dio->size; |
|
/* check for short read */ |
|
if (offset + ret > dio->i_size && |
|
!(dio->flags & IOMAP_DIO_WRITE)) |
|
ret = dio->i_size - offset; |
|
iocb->ki_pos += ret; |
|
} |
|
|
|
/* |
|
* Try again to invalidate clean pages which might have been cached by |
|
* non-direct readahead, or faulted in by get_user_pages() if the source |
|
* of the write was an mmap'ed region of the file we're writing. Either |
|
* one is a pretty crazy thing to do, so we don't support it 100%. If |
|
* this invalidation fails, tough, the write still worked... |
|
* |
|
* And this page cache invalidation has to be after ->end_io(), as some |
|
* filesystems convert unwritten extents to real allocations in |
|
* ->end_io() when necessary, otherwise a racing buffer read would cache |
|
* zeros from unwritten extents. |
|
*/ |
|
if (!dio->error && dio->size && |
|
(dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) { |
|
int err; |
|
err = invalidate_inode_pages2_range(inode->i_mapping, |
|
offset >> PAGE_SHIFT, |
|
(offset + dio->size - 1) >> PAGE_SHIFT); |
|
if (err) |
|
dio_warn_stale_pagecache(iocb->ki_filp); |
|
} |
|
|
|
inode_dio_end(file_inode(iocb->ki_filp)); |
|
/* |
|
* If this is a DSYNC write, make sure we push it to stable storage now |
|
* that we've written data. |
|
*/ |
|
if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) |
|
ret = generic_write_sync(iocb, ret); |
|
|
|
if (ret > 0) |
|
ret += dio->done_before; |
|
|
|
kfree(dio); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(iomap_dio_complete); |
|
|
|
static void iomap_dio_complete_work(struct work_struct *work) |
|
{ |
|
struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work); |
|
struct kiocb *iocb = dio->iocb; |
|
|
|
iocb->ki_complete(iocb, iomap_dio_complete(dio)); |
|
} |
|
|
|
/* |
|
* Set an error in the dio if none is set yet. We have to use cmpxchg |
|
* as the submission context and the completion context(s) can race to |
|
* update the error. |
|
*/ |
|
static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret) |
|
{ |
|
cmpxchg(&dio->error, 0, ret); |
|
} |
|
|
|
void iomap_dio_bio_end_io(struct bio *bio) |
|
{ |
|
struct iomap_dio *dio = bio->bi_private; |
|
bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY); |
|
|
|
if (bio->bi_status) |
|
iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status)); |
|
|
|
if (atomic_dec_and_test(&dio->ref)) { |
|
if (dio->wait_for_completion) { |
|
struct task_struct *waiter = dio->submit.waiter; |
|
WRITE_ONCE(dio->submit.waiter, NULL); |
|
blk_wake_io_task(waiter); |
|
} else if (dio->flags & IOMAP_DIO_WRITE) { |
|
struct inode *inode = file_inode(dio->iocb->ki_filp); |
|
|
|
WRITE_ONCE(dio->iocb->private, NULL); |
|
INIT_WORK(&dio->aio.work, iomap_dio_complete_work); |
|
queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work); |
|
} else { |
|
WRITE_ONCE(dio->iocb->private, NULL); |
|
iomap_dio_complete_work(&dio->aio.work); |
|
} |
|
} |
|
|
|
if (should_dirty) { |
|
bio_check_pages_dirty(bio); |
|
} else { |
|
bio_release_pages(bio, false); |
|
bio_put(bio); |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(iomap_dio_bio_end_io); |
|
|
|
static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, |
|
loff_t pos, unsigned len) |
|
{ |
|
struct inode *inode = file_inode(dio->iocb->ki_filp); |
|
struct page *page = ZERO_PAGE(0); |
|
struct bio *bio; |
|
|
|
bio = iomap_dio_alloc_bio(iter, dio, 1, REQ_OP_WRITE | REQ_SYNC | REQ_IDLE); |
|
fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits, |
|
GFP_KERNEL); |
|
bio->bi_iter.bi_sector = iomap_sector(&iter->iomap, pos); |
|
bio->bi_private = dio; |
|
bio->bi_end_io = iomap_dio_bio_end_io; |
|
|
|
get_page(page); |
|
__bio_add_page(bio, page, len, 0); |
|
iomap_dio_submit_bio(iter, dio, bio, pos); |
|
} |
|
|
|
/* |
|
* Figure out the bio's operation flags from the dio request, the |
|
* mapping, and whether or not we want FUA. Note that we can end up |
|
* clearing the WRITE_FUA flag in the dio request. |
|
*/ |
|
static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio, |
|
const struct iomap *iomap, bool use_fua) |
|
{ |
|
blk_opf_t opflags = REQ_SYNC | REQ_IDLE; |
|
|
|
if (!(dio->flags & IOMAP_DIO_WRITE)) { |
|
WARN_ON_ONCE(iomap->flags & IOMAP_F_ZONE_APPEND); |
|
return REQ_OP_READ; |
|
} |
|
|
|
if (iomap->flags & IOMAP_F_ZONE_APPEND) |
|
opflags |= REQ_OP_ZONE_APPEND; |
|
else |
|
opflags |= REQ_OP_WRITE; |
|
|
|
if (use_fua) |
|
opflags |= REQ_FUA; |
|
else |
|
dio->flags &= ~IOMAP_DIO_WRITE_FUA; |
|
|
|
return opflags; |
|
} |
|
|
|
static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, |
|
struct iomap_dio *dio) |
|
{ |
|
const struct iomap *iomap = &iter->iomap; |
|
struct inode *inode = iter->inode; |
|
unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev)); |
|
unsigned int fs_block_size = i_blocksize(inode), pad; |
|
loff_t length = iomap_length(iter); |
|
loff_t pos = iter->pos; |
|
blk_opf_t bio_opf; |
|
struct bio *bio; |
|
bool need_zeroout = false; |
|
bool use_fua = false; |
|
int nr_pages, ret = 0; |
|
size_t copied = 0; |
|
size_t orig_count; |
|
|
|
if ((pos | length) & ((1 << blkbits) - 1) || |
|
!bdev_iter_is_aligned(iomap->bdev, dio->submit.iter)) |
|
return -EINVAL; |
|
|
|
if (iomap->type == IOMAP_UNWRITTEN) { |
|
dio->flags |= IOMAP_DIO_UNWRITTEN; |
|
need_zeroout = true; |
|
} |
|
|
|
if (iomap->flags & IOMAP_F_SHARED) |
|
dio->flags |= IOMAP_DIO_COW; |
|
|
|
if (iomap->flags & IOMAP_F_NEW) { |
|
need_zeroout = true; |
|
} else if (iomap->type == IOMAP_MAPPED) { |
|
/* |
|
* Use a FUA write if we need datasync semantics, this is a pure |
|
* data IO that doesn't require any metadata updates (including |
|
* after IO completion such as unwritten extent conversion) and |
|
* the underlying device supports FUA. This allows us to avoid |
|
* cache flushes on IO completion. |
|
*/ |
|
if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && |
|
(dio->flags & IOMAP_DIO_WRITE_FUA) && bdev_fua(iomap->bdev)) |
|
use_fua = true; |
|
} |
|
|
|
/* |
|
* Save the original count and trim the iter to just the extent we |
|
* are operating on right now. The iter will be re-expanded once |
|
* we are done. |
|
*/ |
|
orig_count = iov_iter_count(dio->submit.iter); |
|
iov_iter_truncate(dio->submit.iter, length); |
|
|
|
if (!iov_iter_count(dio->submit.iter)) |
|
goto out; |
|
|
|
/* |
|
* We can only poll for single bio I/Os. |
|
*/ |
|
if (need_zeroout || |
|
((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) |
|
dio->iocb->ki_flags &= ~IOCB_HIPRI; |
|
|
|
if (need_zeroout) { |
|
/* zero out from the start of the block to the write offset */ |
|
pad = pos & (fs_block_size - 1); |
|
if (pad) |
|
iomap_dio_zero(iter, dio, pos - pad, pad); |
|
} |
|
|
|
/* |
|
* Set the operation flags early so that bio_iov_iter_get_pages |
|
* can set up the page vector appropriately for a ZONE_APPEND |
|
* operation. |
|
*/ |
|
bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua); |
|
|
|
nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_VECS); |
|
do { |
|
size_t n; |
|
if (dio->error) { |
|
iov_iter_revert(dio->submit.iter, copied); |
|
copied = ret = 0; |
|
goto out; |
|
} |
|
|
|
bio = iomap_dio_alloc_bio(iter, dio, nr_pages, bio_opf); |
|
fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits, |
|
GFP_KERNEL); |
|
bio->bi_iter.bi_sector = iomap_sector(iomap, pos); |
|
bio->bi_ioprio = dio->iocb->ki_ioprio; |
|
bio->bi_private = dio; |
|
bio->bi_end_io = iomap_dio_bio_end_io; |
|
|
|
ret = bio_iov_iter_get_pages(bio, dio->submit.iter); |
|
if (unlikely(ret)) { |
|
/* |
|
* We have to stop part way through an IO. We must fall |
|
* through to the sub-block tail zeroing here, otherwise |
|
* this short IO may expose stale data in the tail of |
|
* the block we haven't written data to. |
|
*/ |
|
bio_put(bio); |
|
goto zero_tail; |
|
} |
|
|
|
n = bio->bi_iter.bi_size; |
|
if (dio->flags & IOMAP_DIO_WRITE) { |
|
task_io_account_write(n); |
|
} else { |
|
if (dio->flags & IOMAP_DIO_DIRTY) |
|
bio_set_pages_dirty(bio); |
|
} |
|
|
|
dio->size += n; |
|
copied += n; |
|
|
|
nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, |
|
BIO_MAX_VECS); |
|
/* |
|
* We can only poll for single bio I/Os. |
|
*/ |
|
if (nr_pages) |
|
dio->iocb->ki_flags &= ~IOCB_HIPRI; |
|
iomap_dio_submit_bio(iter, dio, bio, pos); |
|
pos += n; |
|
} while (nr_pages); |
|
|
|
/* |
|
* We need to zeroout the tail of a sub-block write if the extent type |
|
* requires zeroing or the write extends beyond EOF. If we don't zero |
|
* the block tail in the latter case, we can expose stale data via mmap |
|
* reads of the EOF block. |
|
*/ |
|
zero_tail: |
|
if (need_zeroout || |
|
((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) { |
|
/* zero out from the end of the write to the end of the block */ |
|
pad = pos & (fs_block_size - 1); |
|
if (pad) |
|
iomap_dio_zero(iter, dio, pos, fs_block_size - pad); |
|
} |
|
out: |
|
/* Undo iter limitation to current extent */ |
|
iov_iter_reexpand(dio->submit.iter, orig_count - copied); |
|
if (copied) |
|
return copied; |
|
return ret; |
|
} |
|
|
|
static loff_t iomap_dio_hole_iter(const struct iomap_iter *iter, |
|
struct iomap_dio *dio) |
|
{ |
|
loff_t length = iov_iter_zero(iomap_length(iter), dio->submit.iter); |
|
|
|
dio->size += length; |
|
if (!length) |
|
return -EFAULT; |
|
return length; |
|
} |
|
|
|
static loff_t iomap_dio_inline_iter(const struct iomap_iter *iomi, |
|
struct iomap_dio *dio) |
|
{ |
|
const struct iomap *iomap = &iomi->iomap; |
|
struct iov_iter *iter = dio->submit.iter; |
|
void *inline_data = iomap_inline_data(iomap, iomi->pos); |
|
loff_t length = iomap_length(iomi); |
|
loff_t pos = iomi->pos; |
|
size_t copied; |
|
|
|
if (WARN_ON_ONCE(!iomap_inline_data_valid(iomap))) |
|
return -EIO; |
|
|
|
if (dio->flags & IOMAP_DIO_WRITE) { |
|
loff_t size = iomi->inode->i_size; |
|
|
|
if (pos > size) |
|
memset(iomap_inline_data(iomap, size), 0, pos - size); |
|
copied = copy_from_iter(inline_data, length, iter); |
|
if (copied) { |
|
if (pos + copied > size) |
|
i_size_write(iomi->inode, pos + copied); |
|
mark_inode_dirty(iomi->inode); |
|
} |
|
} else { |
|
copied = copy_to_iter(inline_data, length, iter); |
|
} |
|
dio->size += copied; |
|
if (!copied) |
|
return -EFAULT; |
|
return copied; |
|
} |
|
|
|
static loff_t iomap_dio_iter(const struct iomap_iter *iter, |
|
struct iomap_dio *dio) |
|
{ |
|
switch (iter->iomap.type) { |
|
case IOMAP_HOLE: |
|
if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) |
|
return -EIO; |
|
return iomap_dio_hole_iter(iter, dio); |
|
case IOMAP_UNWRITTEN: |
|
if (!(dio->flags & IOMAP_DIO_WRITE)) |
|
return iomap_dio_hole_iter(iter, dio); |
|
return iomap_dio_bio_iter(iter, dio); |
|
case IOMAP_MAPPED: |
|
return iomap_dio_bio_iter(iter, dio); |
|
case IOMAP_INLINE: |
|
return iomap_dio_inline_iter(iter, dio); |
|
case IOMAP_DELALLOC: |
|
/* |
|
* DIO is not serialised against mmap() access at all, and so |
|
* if the page_mkwrite occurs between the writeback and the |
|
* iomap_iter() call in the DIO path, then it will see the |
|
* DELALLOC block that the page-mkwrite allocated. |
|
*/ |
|
pr_warn_ratelimited("Direct I/O collision with buffered writes! File: %pD4 Comm: %.20s\n", |
|
dio->iocb->ki_filp, current->comm); |
|
return -EIO; |
|
default: |
|
WARN_ON_ONCE(1); |
|
return -EIO; |
|
} |
|
} |
|
|
|
/* |
|
* iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO |
|
* is being issued as AIO or not. This allows us to optimise pure data writes |
|
* to use REQ_FUA rather than requiring generic_write_sync() to issue a |
|
* REQ_FLUSH post write. This is slightly tricky because a single request here |
|
* can be mapped into multiple disjoint IOs and only a subset of the IOs issued |
|
* may be pure data writes. In that case, we still need to do a full data sync |
|
* completion. |
|
* |
|
* When page faults are disabled and @dio_flags includes IOMAP_DIO_PARTIAL, |
|
* __iomap_dio_rw can return a partial result if it encounters a non-resident |
|
* page in @iter after preparing a transfer. In that case, the non-resident |
|
* pages can be faulted in and the request resumed with @done_before set to the |
|
* number of bytes previously transferred. The request will then complete with |
|
* the correct total number of bytes transferred; this is essential for |
|
* completing partial requests asynchronously. |
|
* |
|
* Returns -ENOTBLK In case of a page invalidation invalidation failure for |
|
* writes. The callers needs to fall back to buffered I/O in this case. |
|
*/ |
|
struct iomap_dio * |
|
__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, |
|
const struct iomap_ops *ops, const struct iomap_dio_ops *dops, |
|
unsigned int dio_flags, void *private, size_t done_before) |
|
{ |
|
struct address_space *mapping = iocb->ki_filp->f_mapping; |
|
struct inode *inode = file_inode(iocb->ki_filp); |
|
struct iomap_iter iomi = { |
|
.inode = inode, |
|
.pos = iocb->ki_pos, |
|
.len = iov_iter_count(iter), |
|
.flags = IOMAP_DIRECT, |
|
.private = private, |
|
}; |
|
loff_t end = iomi.pos + iomi.len - 1, ret = 0; |
|
bool wait_for_completion = |
|
is_sync_kiocb(iocb) || (dio_flags & IOMAP_DIO_FORCE_WAIT); |
|
struct blk_plug plug; |
|
struct iomap_dio *dio; |
|
|
|
if (!iomi.len) |
|
return NULL; |
|
|
|
dio = kmalloc(sizeof(*dio), GFP_KERNEL); |
|
if (!dio) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
dio->iocb = iocb; |
|
atomic_set(&dio->ref, 1); |
|
dio->size = 0; |
|
dio->i_size = i_size_read(inode); |
|
dio->dops = dops; |
|
dio->error = 0; |
|
dio->flags = 0; |
|
dio->done_before = done_before; |
|
|
|
dio->submit.iter = iter; |
|
dio->submit.waiter = current; |
|
dio->submit.poll_bio = NULL; |
|
|
|
if (iov_iter_rw(iter) == READ) { |
|
if (iomi.pos >= dio->i_size) |
|
goto out_free_dio; |
|
|
|
if (iocb->ki_flags & IOCB_NOWAIT) { |
|
if (filemap_range_needs_writeback(mapping, iomi.pos, |
|
end)) { |
|
ret = -EAGAIN; |
|
goto out_free_dio; |
|
} |
|
iomi.flags |= IOMAP_NOWAIT; |
|
} |
|
|
|
if (user_backed_iter(iter)) |
|
dio->flags |= IOMAP_DIO_DIRTY; |
|
} else { |
|
iomi.flags |= IOMAP_WRITE; |
|
dio->flags |= IOMAP_DIO_WRITE; |
|
|
|
if (iocb->ki_flags & IOCB_NOWAIT) { |
|
if (filemap_range_has_page(mapping, iomi.pos, end)) { |
|
ret = -EAGAIN; |
|
goto out_free_dio; |
|
} |
|
iomi.flags |= IOMAP_NOWAIT; |
|
} |
|
|
|
/* for data sync or sync, we need sync completion processing */ |
|
if (iocb_is_dsync(iocb) && !(dio_flags & IOMAP_DIO_NOSYNC)) { |
|
dio->flags |= IOMAP_DIO_NEED_SYNC; |
|
|
|
/* |
|
* For datasync only writes, we optimistically try |
|
* using FUA for this IO. Any non-FUA write that |
|
* occurs will clear this flag, hence we know before |
|
* completion whether a cache flush is necessary. |
|
*/ |
|
if (!(iocb->ki_flags & IOCB_SYNC)) |
|
dio->flags |= IOMAP_DIO_WRITE_FUA; |
|
} |
|
} |
|
|
|
if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { |
|
ret = -EAGAIN; |
|
if (iomi.pos >= dio->i_size || |
|
iomi.pos + iomi.len > dio->i_size) |
|
goto out_free_dio; |
|
iomi.flags |= IOMAP_OVERWRITE_ONLY; |
|
} |
|
|
|
ret = filemap_write_and_wait_range(mapping, iomi.pos, end); |
|
if (ret) |
|
goto out_free_dio; |
|
|
|
if (iov_iter_rw(iter) == WRITE) { |
|
/* |
|
* Try to invalidate cache pages for the range we are writing. |
|
* If this invalidation fails, let the caller fall back to |
|
* buffered I/O. |
|
*/ |
|
if (invalidate_inode_pages2_range(mapping, |
|
iomi.pos >> PAGE_SHIFT, end >> PAGE_SHIFT)) { |
|
trace_iomap_dio_invalidate_fail(inode, iomi.pos, |
|
iomi.len); |
|
ret = -ENOTBLK; |
|
goto out_free_dio; |
|
} |
|
|
|
if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) { |
|
ret = sb_init_dio_done_wq(inode->i_sb); |
|
if (ret < 0) |
|
goto out_free_dio; |
|
} |
|
} |
|
|
|
inode_dio_begin(inode); |
|
|
|
blk_start_plug(&plug); |
|
while ((ret = iomap_iter(&iomi, ops)) > 0) { |
|
iomi.processed = iomap_dio_iter(&iomi, dio); |
|
|
|
/* |
|
* We can only poll for single bio I/Os. |
|
*/ |
|
iocb->ki_flags &= ~IOCB_HIPRI; |
|
} |
|
|
|
blk_finish_plug(&plug); |
|
|
|
/* |
|
* We only report that we've read data up to i_size. |
|
* Revert iter to a state corresponding to that as some callers (such |
|
* as the splice code) rely on it. |
|
*/ |
|
if (iov_iter_rw(iter) == READ && iomi.pos >= dio->i_size) |
|
iov_iter_revert(iter, iomi.pos - dio->i_size); |
|
|
|
if (ret == -EFAULT && dio->size && (dio_flags & IOMAP_DIO_PARTIAL)) { |
|
if (!(iocb->ki_flags & IOCB_NOWAIT)) |
|
wait_for_completion = true; |
|
ret = 0; |
|
} |
|
|
|
/* magic error code to fall back to buffered I/O */ |
|
if (ret == -ENOTBLK) { |
|
wait_for_completion = true; |
|
ret = 0; |
|
} |
|
if (ret < 0) |
|
iomap_dio_set_error(dio, ret); |
|
|
|
/* |
|
* If all the writes we issued were FUA, we don't need to flush the |
|
* cache on IO completion. Clear the sync flag for this case. |
|
*/ |
|
if (dio->flags & IOMAP_DIO_WRITE_FUA) |
|
dio->flags &= ~IOMAP_DIO_NEED_SYNC; |
|
|
|
WRITE_ONCE(iocb->private, dio->submit.poll_bio); |
|
|
|
/* |
|
* We are about to drop our additional submission reference, which |
|
* might be the last reference to the dio. There are three different |
|
* ways we can progress here: |
|
* |
|
* (a) If this is the last reference we will always complete and free |
|
* the dio ourselves. |
|
* (b) If this is not the last reference, and we serve an asynchronous |
|
* iocb, we must never touch the dio after the decrement, the |
|
* I/O completion handler will complete and free it. |
|
* (c) If this is not the last reference, but we serve a synchronous |
|
* iocb, the I/O completion handler will wake us up on the drop |
|
* of the final reference, and we will complete and free it here |
|
* after we got woken by the I/O completion handler. |
|
*/ |
|
dio->wait_for_completion = wait_for_completion; |
|
if (!atomic_dec_and_test(&dio->ref)) { |
|
if (!wait_for_completion) |
|
return ERR_PTR(-EIOCBQUEUED); |
|
|
|
for (;;) { |
|
set_current_state(TASK_UNINTERRUPTIBLE); |
|
if (!READ_ONCE(dio->submit.waiter)) |
|
break; |
|
|
|
blk_io_schedule(); |
|
} |
|
__set_current_state(TASK_RUNNING); |
|
} |
|
|
|
return dio; |
|
|
|
out_free_dio: |
|
kfree(dio); |
|
if (ret) |
|
return ERR_PTR(ret); |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL_GPL(__iomap_dio_rw); |
|
|
|
ssize_t |
|
iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, |
|
const struct iomap_ops *ops, const struct iomap_dio_ops *dops, |
|
unsigned int dio_flags, void *private, size_t done_before) |
|
{ |
|
struct iomap_dio *dio; |
|
|
|
dio = __iomap_dio_rw(iocb, iter, ops, dops, dio_flags, private, |
|
done_before); |
|
if (IS_ERR_OR_NULL(dio)) |
|
return PTR_ERR_OR_ZERO(dio); |
|
return iomap_dio_complete(dio); |
|
} |
|
EXPORT_SYMBOL_GPL(iomap_dio_rw);
|
|
|