diff options
Diffstat (limited to 'fs/iomap/direct-io.c')
| -rw-r--r-- | fs/iomap/direct-io.c | 757 |
1 files changed, 516 insertions, 241 deletions
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index ec7b78e6feca..8e273408453a 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -1,15 +1,14 @@ // SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2010 Red Hat, Inc. - * Copyright (c) 2016-2018 Christoph Hellwig. + * Copyright (c) 2016-2025 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 "internal.h" +#include "trace.h" #include "../internal.h" @@ -17,10 +16,12 @@ * 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) +#define IOMAP_DIO_NO_INVALIDATE (1U << 26) +#define IOMAP_DIO_COMP_WORK (1U << 27) +#define IOMAP_DIO_WRITE_THROUGH (1U << 28) +#define IOMAP_DIO_NEED_SYNC (1U << 29) +#define IOMAP_DIO_WRITE (1U << 30) +#define IOMAP_DIO_DIRTY (1U << 31) struct iomap_dio { struct kiocb *iocb; @@ -30,6 +31,7 @@ struct iomap_dio { atomic_t ref; unsigned flags; int error; + size_t done_before; bool wait_for_completion; union { @@ -37,8 +39,6 @@ struct iomap_dio { struct { struct iov_iter *iter; struct task_struct *waiter; - struct request_queue *last_queue; - blk_qc_t cookie; } submit; /* used for aio completion: */ @@ -48,38 +48,40 @@ 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, loff_t pos) +static void iomap_dio_submit_bio(const struct iomap_iter *iter, + struct iomap_dio *dio, struct bio *bio, loff_t pos) { + struct kiocb *iocb = dio->iocb; + atomic_inc(&dio->ref); - if (dio->iocb->ki_flags & IOCB_HIPRI) - bio_set_polled(bio, dio->iocb); + /* Sync dio can't be polled reliably */ + if ((iocb->ki_flags & IOCB_HIPRI) && !is_sync_kiocb(iocb)) { + bio_set_polled(bio, iocb); + WRITE_ONCE(iocb->private, bio); + } - dio->submit.last_queue = bdev_get_queue(iomap->bdev); - if (dio->dops && dio->dops->submit_io) - dio->submit.cookie = dio->dops->submit_io( - file_inode(dio->iocb->ki_filp), - iomap, bio, pos); - else - dio->submit.cookie = submit_bio(bio); + if (dio->dops && dio->dops->submit_io) { + dio->dops->submit_io(iter, bio, pos); + } else { + WARN_ON_ONCE(iter->iomap.flags & IOMAP_F_ANON_WRITE); + 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; - struct inode *inode = file_inode(iocb->ki_filp); loff_t offset = iocb->ki_pos; ssize_t ret = dio->error; @@ -92,7 +94,6 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) if (offset + ret > dio->i_size && !(dio->flags & IOMAP_DIO_WRITE)) ret = dio->i_size - offset; - iocb->ki_pos += ret; } /* @@ -107,35 +108,36 @@ 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 && - (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); - } - - /* - * 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 (!dio->error && dio->size && (dio->flags & IOMAP_DIO_WRITE) && + !(dio->flags & IOMAP_DIO_NO_INVALIDATE)) + kiocb_invalidate_post_direct_write(iocb, dio->size); inode_dio_end(file_inode(iocb->ki_filp)); - kfree(dio); + if (ret > 0) { + iocb->ki_pos += ret; + + /* + * If this is a DSYNC write, make sure we push it to stable + * storage now that we've written data. + */ + if (dio->flags & IOMAP_DIO_NEED_SYNC) + ret = generic_write_sync(iocb, ret); + if (ret > 0) + ret += dio->done_before; + } + trace_iomap_dio_complete(iocb, dio->error, ret); + 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)); } /* @@ -148,7 +150,67 @@ 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) +/* + * Called when dio->ref reaches zero from an I/O completion. + */ +static void iomap_dio_done(struct iomap_dio *dio) +{ + struct kiocb *iocb = dio->iocb; + + if (dio->wait_for_completion) { + /* + * Synchronous I/O, task itself will handle any completion work + * that needs after IO. All we need to do is wake the task. + */ + struct task_struct *waiter = dio->submit.waiter; + + WRITE_ONCE(dio->submit.waiter, NULL); + blk_wake_io_task(waiter); + return; + } + + /* + * Always run error completions in user context. These are not + * performance critical and some code relies on taking sleeping locks + * for error handling. + */ + if (dio->error) + dio->flags |= IOMAP_DIO_COMP_WORK; + + /* + * Never invalidate pages from this context to avoid deadlocks with + * buffered I/O completions when called from the ioend workqueue, + * or avoid sleeping when called directly from ->bi_end_io. + * Tough luck if you hit the tiny race with someone dirtying the range + * right between this check and the actual completion. + */ + if ((dio->flags & IOMAP_DIO_WRITE) && + !(dio->flags & IOMAP_DIO_COMP_WORK)) { + if (dio->iocb->ki_filp->f_mapping->nrpages) + dio->flags |= IOMAP_DIO_COMP_WORK; + else + dio->flags |= IOMAP_DIO_NO_INVALIDATE; + } + + if (dio->flags & IOMAP_DIO_COMP_WORK) { + struct inode *inode = file_inode(iocb->ki_filp); + + /* + * Async DIO completion that requires filesystem level + * completion work gets punted to a work queue to complete as + * the operation may require more IO to be issued to finalise + * filesystem metadata changes or guarantee data integrity. + */ + INIT_WORK(&dio->aio.work, iomap_dio_complete_work); + queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work); + return; + } + + WRITE_ONCE(iocb->private, NULL); + iomap_dio_complete_work(&dio->aio.work); +} + +void iomap_dio_bio_end_io(struct bio *bio) { struct iomap_dio *dio = bio->bi_private; bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY); @@ -156,20 +218,8 @@ static void iomap_dio_bio_end_io(struct bio *bio) 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); - - INIT_WORK(&dio->aio.work, iomap_dio_complete_work); - queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work); - } else { - iomap_dio_complete_work(&dio->aio.work); - } - } + if (atomic_dec_and_test(&dio->ref)) + iomap_dio_done(dio); if (should_dirty) { bio_check_pages_dirty(bio); @@ -178,66 +228,187 @@ static void iomap_dio_bio_end_io(struct bio *bio) bio_put(bio); } } +EXPORT_SYMBOL_GPL(iomap_dio_bio_end_io); + +u32 iomap_finish_ioend_direct(struct iomap_ioend *ioend) +{ + struct iomap_dio *dio = ioend->io_bio.bi_private; + bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY); + u32 vec_count = ioend->io_bio.bi_vcnt; + + if (ioend->io_error) + iomap_dio_set_error(dio, ioend->io_error); + + if (atomic_dec_and_test(&dio->ref)) { + /* + * Try to avoid another context switch for the completion given + * that we are already called from the ioend completion + * workqueue. + */ + dio->flags &= ~IOMAP_DIO_COMP_WORK; + iomap_dio_done(dio); + } + + if (should_dirty) { + bio_check_pages_dirty(&ioend->io_bio); + } else { + bio_release_pages(&ioend->io_bio, false); + bio_put(&ioend->io_bio); + } + + /* + * Return the number of bvecs completed as even direct I/O completions + * do significant per-folio work and we'll still want to give up the + * CPU after a lot of completions. + */ + return vec_count; +} -static void -iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, - unsigned len) +static int iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, + loff_t pos, unsigned len) { - struct page *page = ZERO_PAGE(0); - int flags = REQ_SYNC | REQ_IDLE; + struct inode *inode = file_inode(dio->iocb->ki_filp); struct bio *bio; + struct folio *zero_folio = largest_zero_folio(); + int nr_vecs = max(1, i_blocksize(inode) / folio_size(zero_folio)); + + if (!len) + return 0; + + /* + * This limit shall never be reached as most filesystems have a + * maximum blocksize of 64k. + */ + if (WARN_ON_ONCE(nr_vecs > BIO_MAX_VECS)) + return -EINVAL; - 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, nr_vecs, + 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, pos); + while (len > 0) { + unsigned int io_len = min(len, folio_size(zero_folio)); + + bio_add_folio_nofail(bio, zero_folio, io_len, 0); + len -= io_len; + } + iomap_dio_submit_bio(iter, dio, bio, pos); + + return 0; } -static loff_t -iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, - struct iomap_dio *dio, struct iomap *iomap) +static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio) { - unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev)); + const struct iomap *iomap = &iter->iomap; + struct inode *inode = iter->inode; unsigned int fs_block_size = i_blocksize(inode), pad; - unsigned int align = iov_iter_alignment(dio->submit.iter); + const loff_t length = iomap_length(iter); + loff_t pos = iter->pos; + blk_opf_t bio_opf = REQ_SYNC | REQ_IDLE; struct bio *bio; bool need_zeroout = false; - bool use_fua = false; int nr_pages, ret = 0; - size_t copied = 0; + u64 copied = 0; size_t orig_count; + unsigned int alignment; + + /* + * File systems that write out of place and always allocate new blocks + * need each bio to be block aligned as that's the unit of allocation. + */ + if (dio->flags & IOMAP_DIO_FSBLOCK_ALIGNED) + alignment = fs_block_size; + else + alignment = bdev_logical_block_size(iomap->bdev); - if ((pos | length | align) & ((1 << blkbits) - 1)) + if ((pos | length) & (alignment - 1)) return -EINVAL; - if (iomap->type == IOMAP_UNWRITTEN) { - dio->flags |= IOMAP_DIO_UNWRITTEN; - need_zeroout = true; - } + if (dio->flags & IOMAP_DIO_WRITE) { + bool need_completion_work = true; + + switch (iomap->type) { + case IOMAP_MAPPED: + /* + * Directly mapped I/O does not inherently need to do + * work at I/O completion time. But there are various + * cases below where this will get set again. + */ + need_completion_work = false; + break; + case IOMAP_UNWRITTEN: + dio->flags |= IOMAP_DIO_UNWRITTEN; + need_zeroout = true; + break; + default: + break; + } + + if (iomap->flags & IOMAP_F_ATOMIC_BIO) { + /* + * Ensure that the mapping covers the full write + * length, otherwise it won't be submitted as a single + * bio, which is required to use hardware atomics. + */ + if (length != iter->len) + return -EINVAL; + bio_opf |= REQ_ATOMIC; + } + + if (iomap->flags & IOMAP_F_SHARED) { + /* + * Unsharing of needs to update metadata at I/O + * completion time. + */ + need_completion_work = true; + dio->flags |= IOMAP_DIO_COW; + } + + if (iomap->flags & IOMAP_F_NEW) { + /* + * Newly allocated blocks might need recording in + * metadata at I/O completion time. + */ + need_completion_work = true; + need_zeroout = true; + } - if (iomap->flags & IOMAP_F_SHARED) - dio->flags |= IOMAP_DIO_COW; + /* + * Use a FUA write if we need datasync semantics and this is a + * pure overwrite that doesn't require any metadata updates. + * + * This allows us to avoid cache flushes on I/O completion. + */ + if (dio->flags & IOMAP_DIO_WRITE_THROUGH) { + if (!need_completion_work && + !(iomap->flags & IOMAP_F_DIRTY) && + (!bdev_write_cache(iomap->bdev) || + bdev_fua(iomap->bdev))) + bio_opf |= REQ_FUA; + else + dio->flags &= ~IOMAP_DIO_WRITE_THROUGH; + } - 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. + * We can only do inline completion for pure overwrites that + * don't require additional I/O at completion time. + * + * This rules out writes that need zeroing or metdata updates to + * convert unwritten or shared extents. + * + * Writes that extend i_size are also not supported, but this is + * handled in __iomap_dio_rw(). */ - if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && - (dio->flags & IOMAP_DIO_WRITE_FUA) && - blk_queue_fua(bdev_get_queue(iomap->bdev))) - use_fua = true; + if (need_completion_work) + dio->flags |= IOMAP_DIO_COMP_WORK; + + bio_opf |= REQ_OP_WRITE; + } else { + bio_opf |= REQ_OP_READ; } /* @@ -248,19 +419,27 @@ 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; - } + + /* + * The rules for polled IO completions follow the guidelines as the + * ones we set for inline and deferred completions. If none of those + * are available for this IO, clear the polled flag. + */ + if (dio->flags & IOMAP_DIO_COMP_WORK) + 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); + + ret = iomap_dio_zero(iter, dio, pos - pad, pad); + if (ret) + goto out; } + nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_VECS); do { size_t n; if (dio->error) { @@ -269,15 +448,17 @@ 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_write_hint = inode->i_write_hint; 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); + ret = bio_iov_iter_get_pages(bio, dio->submit.iter, + alignment - 1); if (unlikely(ret)) { /* * We have to stop part way through an IO. We must fall @@ -290,24 +471,33 @@ 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); + if (WARN_ON_ONCE((bio_opf & REQ_ATOMIC) && n != length)) { + /* + * An atomic write bio must cover the complete length, + * which it doesn't, so error. We may need to zero out + * the tail (complete FS block), similar to when + * bio_iov_iter_get_pages() returns an error, above. + */ + ret = -EINVAL; + bio_put(bio); + goto zero_tail; } + 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 = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); - iomap_dio_submit_bio(dio, iomap, bio, pos); + 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); @@ -323,70 +513,87 @@ 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); + ret = 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 iomap_iter_advance(iter, copied); return ret; } -static loff_t -iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio) +static int iomap_dio_hole_iter(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; - return length; + if (!length) + return -EFAULT; + return iomap_iter_advance(iter, 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 int iomap_dio_inline_iter(struct iomap_iter *iomi, struct iomap_dio *dio) { + const struct iomap *iomap = &iomi->iomap; struct iov_iter *iter = dio->submit.iter; - size_t copied; + void *inline_data = iomap_inline_data(iomap, iomi->pos); + loff_t length = iomap_length(iomi); + loff_t pos = iomi->pos; + u64 copied; + + if (WARN_ON_ONCE(!inline_data)) + return -EIO; - 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; - return copied; + if (!copied) + return -EFAULT; + return iomap_iter_advance(iomi, 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 int iomap_dio_iter(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; @@ -401,30 +608,45 @@ 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, + }; + bool wait_for_completion = + is_sync_kiocb(iocb) || (dio_flags & IOMAP_DIO_FORCE_WAIT); struct blk_plug plug; struct iomap_dio *dio; + loff_t ret = 0; - if (!count) - return 0; + trace_iomap_dio_rw_begin(iocb, iter, dio_flags, done_before); - 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); @@ -433,62 +655,92 @@ 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; + + if (iocb->ki_flags & IOCB_NOWAIT) + iomi.flags |= IOMAP_NOWAIT; + + if (dio_flags & IOMAP_DIO_FSBLOCK_ALIGNED) + dio->flags |= IOMAP_DIO_FSBLOCK_ALIGNED; 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 (user_backed_iter(iter)) dio->flags |= IOMAP_DIO_DIRTY; + + ret = kiocb_write_and_wait(iocb, iomi.len); + if (ret) + goto out_free_dio; } else { - flags |= IOMAP_WRITE; + iomi.flags |= IOMAP_WRITE; dio->flags |= IOMAP_DIO_WRITE; + 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; + } + + if (iocb->ki_flags & IOCB_ATOMIC) + iomi.flags |= IOMAP_ATOMIC; + /* 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_NEED_SYNC; + /* + * For datasync only writes, we optimistically try using + * WRITE_THROUGH for this IO. This flag requires either + * FUA writes through the device's write cache, or a + * normal write to a device without a volatile write + * cache. For the former, 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_THROUGH; + } + /* - * 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. + * i_size updates must to happen from process context. */ - if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC) - dio->flags |= IOMAP_DIO_WRITE_FUA; - } + if (iomi.pos + iomi.len > dio->i_size) + dio->flags |= IOMAP_DIO_COMP_WORK; - if (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_has_page(mapping, pos, end)) { - ret = -EAGAIN; + /* + * Try to invalidate cache pages for the range we are writing. + * If this invalidation fails, let the caller fall back to + * buffered I/O. + */ + ret = kiocb_invalidate_pages(iocb, iomi.len); + if (ret) { + if (ret != -EAGAIN) { + trace_iomap_dio_invalidate_fail(inode, iomi.pos, + iomi.len); + if (iocb->ki_flags & IOCB_ATOMIC) { + /* + * folio invalidation failed, maybe + * this is transient, unlock and see if + * the caller tries again. + */ + ret = -EAGAIN; + } else { + /* fall back to buffered write */ + ret = -ENOTBLK; + } + } goto out_free_dio; } - flags |= IOMAP_NOWAIT; } - ret = filemap_write_and_wait_range(mapping, 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) { + 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; @@ -497,43 +749,51 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, 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.status = 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); /* - * 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 all the writes we issued were already written through to the + * media, we don't need to flush the cache on IO completion. Clear the + * sync flag for this case. + * + * Otherwise clear the inline completion flag if any sync work is + * needed, as that needs to be performed from process context. */ - if (dio->flags & IOMAP_DIO_WRITE_FUA) + if (dio->flags & IOMAP_DIO_WRITE_THROUGH) dio->flags &= ~IOMAP_DIO_NEED_SYNC; - - WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie); - WRITE_ONCE(iocb->private, dio->submit.last_queue); + else if (dio->flags & IOMAP_DIO_NEED_SYNC) + dio->flags |= IOMAP_DIO_COMP_WORK; /* * We are about to drop our additional submission reference, which @@ -552,27 +812,42 @@ 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; + if (!wait_for_completion) { + trace_iomap_dio_rw_queued(inode, iomi.pos, iomi.len); + 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)) - blk_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); |