diff options
Diffstat (limited to 'fs/iomap/direct-io.c')
| -rw-r--r-- | fs/iomap/direct-io.c | 447 |
1 files changed, 284 insertions, 163 deletions
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 23837926c0c5..4eb559a16c9e 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -1,15 +1,18 @@ // SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2010 Red Hat, Inc. - * Copyright (c) 2016-2018 Christoph Hellwig. + * 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" @@ -30,6 +33,7 @@ struct iomap_dio { atomic_t ref; unsigned flags; int error; + size_t done_before; bool wait_for_completion; union { @@ -37,8 +41,7 @@ struct iomap_dio { struct { struct iov_iter *iter; struct task_struct *waiter; - struct request_queue *last_queue; - blk_qc_t cookie; + struct bio *poll_bio; } submit; /* used for aio completion: */ @@ -48,29 +51,33 @@ struct iomap_dio { }; }; -int iomap_dio_iopoll(struct kiocb *kiocb, bool spin) +static struct bio *iomap_dio_alloc_bio(const struct iomap_iter *iter, + struct iomap_dio *dio, unsigned short nr_vecs, blk_opf_t opf) { - struct request_queue *q = READ_ONCE(kiocb->private); - - if (!q) - return 0; - return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin); + 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); } -EXPORT_SYMBOL_GPL(iomap_dio_iopoll); -static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, - struct bio *bio) +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); - if (dio->iocb->ki_flags & IOCB_HIPRI) + /* 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; + } - dio->submit.last_queue = bdev_get_queue(iomap->bdev); - dio->submit.cookie = submit_bio(bio); + if (dio->dops && dio->dops->submit_io) + dio->dops->submit_io(iter, bio, pos); + else + submit_bio(bio); } -static ssize_t iomap_dio_complete(struct iomap_dio *dio) +ssize_t iomap_dio_complete(struct iomap_dio *dio) { const struct iomap_dio_ops *dops = dio->dops; struct kiocb *iocb = dio->iocb; @@ -102,7 +109,7 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) * ->end_io() when necessary, otherwise a racing buffer read would cache * zeros from unwritten extents. */ - if (!dio->error && + if (!dio->error && dio->size && (dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) { int err; err = invalidate_inode_pages2_range(inode->i_mapping, @@ -112,6 +119,7 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) 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. @@ -119,18 +127,21 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) ret = generic_write_sync(iocb, ret); - inode_dio_end(file_inode(iocb->ki_filp)); + 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), 0); + iocb->ki_complete(iocb, iomap_dio_complete(dio)); } /* @@ -143,7 +154,7 @@ static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret) cmpxchg(&dio->error, 0, ret); } -static void iomap_dio_bio_end_io(struct bio *bio) +void iomap_dio_bio_end_io(struct bio *bio) { struct iomap_dio *dio = bio->bi_private; bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY); @@ -159,9 +170,11 @@ static void iomap_dio_bio_end_io(struct bio *bio) } 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); } } @@ -173,34 +186,65 @@ static void iomap_dio_bio_end_io(struct bio *bio) bio_put(bio); } } +EXPORT_SYMBOL_GPL(iomap_dio_bio_end_io); -static void -iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, - unsigned len) +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); - int flags = REQ_SYNC | REQ_IDLE; struct bio *bio; - bio = bio_alloc(GFP_KERNEL, 1); - bio_set_dev(bio, iomap->bdev); - bio->bi_iter.bi_sector = iomap_sector(iomap, pos); + 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); - bio_set_op_attrs(bio, REQ_OP_WRITE, flags); - iomap_dio_submit_bio(dio, iomap, bio); + 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_actor(struct inode *inode, loff_t pos, loff_t length, - struct iomap_dio *dio, struct iomap *iomap) +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; - unsigned int align = iov_iter_alignment(dio->submit.iter); + 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; @@ -208,7 +252,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, size_t copied = 0; size_t orig_count; - if ((pos | length | align) & ((1 << blkbits) - 1)) + if ((pos | length) & ((1 << blkbits) - 1) || + !bdev_iter_is_aligned(iomap->bdev, dio->submit.iter)) return -EINVAL; if (iomap->type == IOMAP_UNWRITTEN) { @@ -230,8 +275,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, * cache flushes on IO completion. */ if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && - (dio->flags & IOMAP_DIO_WRITE_FUA) && - blk_queue_fua(bdev_get_queue(iomap->bdev))) + (dio->flags & IOMAP_DIO_WRITE_FUA) && bdev_fua(iomap->bdev)) use_fua = true; } @@ -243,19 +287,31 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, orig_count = iov_iter_count(dio->submit.iter); iov_iter_truncate(dio->submit.iter, length); - nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); - if (nr_pages <= 0) { - ret = nr_pages; + 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(dio, iomap, pos - pad, 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) { @@ -264,10 +320,10 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, goto out; } - bio = bio_alloc(GFP_KERNEL, nr_pages); - bio_set_dev(bio, iomap->bdev); + 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_write_hint = dio->iocb->ki_hint; bio->bi_ioprio = dio->iocb->ki_ioprio; bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; @@ -286,24 +342,24 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, n = bio->bi_iter.bi_size; if (dio->flags & IOMAP_DIO_WRITE) { - bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; - if (use_fua) - bio->bi_opf |= REQ_FUA; - else - dio->flags &= ~IOMAP_DIO_WRITE_FUA; task_io_account_write(n); } else { - bio->bi_opf = REQ_OP_READ; if (dio->flags & IOMAP_DIO_DIRTY) bio_set_pages_dirty(bio); } dio->size += n; - pos += n; copied += n; - nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); - iomap_dio_submit_bio(dio, iomap, bio); + 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); /* @@ -318,7 +374,7 @@ zero_tail: /* 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(dio, iomap, pos, fs_block_size - pad); + iomap_dio_zero(iter, dio, pos, fs_block_size - pad); } out: /* Undo iter limitation to current extent */ @@ -328,60 +384,76 @@ out: return ret; } -static loff_t -iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio) +static loff_t iomap_dio_hole_iter(const struct iomap_iter *iter, + struct iomap_dio *dio) { - length = iov_iter_zero(length, dio->submit.iter); + 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_actor(struct inode *inode, loff_t pos, loff_t length, - struct iomap_dio *dio, struct iomap *iomap) +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; - BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data)); + if (WARN_ON_ONCE(!iomap_inline_data_valid(iomap))) + return -EIO; if (dio->flags & IOMAP_DIO_WRITE) { - loff_t size = inode->i_size; + loff_t size = iomi->inode->i_size; if (pos > size) - memset(iomap->inline_data + size, 0, pos - size); - copied = copy_from_iter(iomap->inline_data + pos, length, iter); + 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(inode, pos + copied); - mark_inode_dirty(inode); + i_size_write(iomi->inode, pos + copied); + mark_inode_dirty(iomi->inode); } } else { - copied = copy_to_iter(iomap->inline_data + pos, length, iter); + copied = copy_to_iter(inline_data, length, iter); } dio->size += copied; + if (!copied) + return -EFAULT; return copied; } -static loff_t -iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap, struct iomap *srcmap) +static loff_t iomap_dio_iter(const struct iomap_iter *iter, + struct iomap_dio *dio) { - struct iomap_dio *dio = data; - - switch (iomap->type) { + switch (iter->iomap.type) { case IOMAP_HOLE: if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) return -EIO; - return iomap_dio_hole_actor(length, dio); + return iomap_dio_hole_iter(iter, dio); case IOMAP_UNWRITTEN: if (!(dio->flags & IOMAP_DIO_WRITE)) - return iomap_dio_hole_actor(length, dio); - return iomap_dio_bio_actor(inode, pos, length, dio, iomap); + return iomap_dio_hole_iter(iter, dio); + return iomap_dio_bio_iter(iter, dio); case IOMAP_MAPPED: - return iomap_dio_bio_actor(inode, pos, length, dio, iomap); + return iomap_dio_bio_iter(iter, dio); case IOMAP_INLINE: - return iomap_dio_inline_actor(inode, pos, length, dio, iomap); + 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; @@ -396,32 +468,44 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, * 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. */ -ssize_t -iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, +struct iomap_dio * +__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops, - bool wait_for_completion) + 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); - size_t count = iov_iter_count(iter); - loff_t pos = iocb->ki_pos; - loff_t end = iocb->ki_pos + count - 1, ret = 0; - unsigned int flags = IOMAP_DIRECT; + 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; - lockdep_assert_held(&inode->i_rwsem); - - if (!count) - return 0; - - if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion)) - return -EIO; + if (!iomi.len) + return NULL; dio = kmalloc(sizeof(*dio), GFP_KERNEL); if (!dio) - return -ENOMEM; + return ERR_PTR(-ENOMEM); dio->iocb = iocb; atomic_set(&dio->ref, 1); @@ -430,95 +514,120 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, dio->dops = dops; dio->error = 0; dio->flags = 0; + dio->done_before = done_before; dio->submit.iter = iter; dio->submit.waiter = current; - dio->submit.cookie = BLK_QC_T_NONE; - dio->submit.last_queue = NULL; + dio->submit.poll_bio = NULL; if (iov_iter_rw(iter) == READ) { - if (pos >= dio->i_size) + if (iomi.pos >= dio->i_size) goto out_free_dio; - if (iter_is_iovec(iter)) + 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 { - flags |= IOMAP_WRITE; + 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->ki_flags & IOCB_DSYNC) + 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_DSYNC | IOCB_SYNC)) == IOCB_DSYNC) - dio->flags |= IOMAP_DIO_WRITE_FUA; + /* + * 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 (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_has_page(mapping, pos, end)) { - ret = -EAGAIN; + 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; - } - flags |= IOMAP_NOWAIT; + iomi.flags |= IOMAP_OVERWRITE_ONLY; } - ret = filemap_write_and_wait_range(mapping, pos, end); + ret = filemap_write_and_wait_range(mapping, iomi.pos, end); if (ret) goto out_free_dio; - /* - * Try to invalidate cache pages for the range we're direct - * writing. If this invalidation fails, tough, the write will - * still work, but racing two incompatible write paths is a - * pretty crazy thing to do, so we don't support it 100%. - */ - ret = invalidate_inode_pages2_range(mapping, - pos >> PAGE_SHIFT, end >> PAGE_SHIFT); - if (ret) - dio_warn_stale_pagecache(iocb->ki_filp); - ret = 0; - - if (iov_iter_rw(iter) == WRITE && !wait_for_completion && - !inode->i_sb->s_dio_done_wq) { - ret = sb_init_dio_done_wq(inode->i_sb); - if (ret < 0) + 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); - do { - ret = iomap_apply(inode, pos, count, flags, ops, dio, - iomap_dio_actor); - if (ret <= 0) { - /* magic error code to fall back to buffered I/O */ - if (ret == -ENOTBLK) { - wait_for_completion = true; - ret = 0; - } - break; - } - pos += ret; + 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; + } - if (iov_iter_rw(iter) == READ && pos >= dio->i_size) { - /* - * 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 splice code) rely on it. - */ - iov_iter_revert(iter, pos - dio->i_size); - break; - } - } while ((count = iov_iter_count(iter)) > 0); 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); @@ -529,13 +638,12 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (dio->flags & IOMAP_DIO_WRITE_FUA) dio->flags &= ~IOMAP_DIO_NEED_SYNC; - WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie); - WRITE_ONCE(iocb->private, dio->submit.last_queue); + 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 three - * different ways we can progress here: + * 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. @@ -550,26 +658,39 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, dio->wait_for_completion = wait_for_completion; if (!atomic_dec_and_test(&dio->ref)) { if (!wait_for_completion) - return -EIOCBQUEUED; + return ERR_PTR(-EIOCBQUEUED); for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); if (!READ_ONCE(dio->submit.waiter)) break; - if (!(iocb->ki_flags & IOCB_HIPRI) || - !dio->submit.last_queue || - !blk_poll(dio->submit.last_queue, - dio->submit.cookie, true)) - io_schedule(); + blk_io_schedule(); } __set_current_state(TASK_RUNNING); } - return iomap_dio_complete(dio); + return dio; out_free_dio: kfree(dio); - return ret; + 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); |