diff options
| -rw-r--r-- | fs/iomap.c | 554 | ||||
| -rw-r--r-- | fs/iomap/Makefile | 1 | ||||
| -rw-r--r-- | fs/iomap/direct-io.c | 562 | ||||
| -rw-r--r-- | include/linux/iomap.h | 7 |
4 files changed, 570 insertions, 554 deletions
diff --git a/fs/iomap.c b/fs/iomap.c index ad994c408cb8..c983fedc7081 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -90,12 +90,6 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, return written ? written : ret; } -static sector_t -iomap_sector(struct iomap *iomap, loff_t pos) -{ - return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; -} - static struct iomap_page * iomap_page_create(struct inode *inode, struct page *page) { @@ -1148,551 +1142,3 @@ out_unlock: return block_page_mkwrite_return(ret); } EXPORT_SYMBOL_GPL(iomap_page_mkwrite); - -/* - * 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; - iomap_dio_end_io_t *end_io; - loff_t i_size; - loff_t size; - atomic_t ref; - unsigned flags; - int error; - bool wait_for_completion; - - union { - /* used during submission and for synchronous completion: */ - struct { - struct iov_iter *iter; - struct task_struct *waiter; - struct request_queue *last_queue; - blk_qc_t cookie; - } submit; - - /* used for aio completion: */ - struct { - struct work_struct work; - } aio; - }; -}; - -int iomap_dio_iopoll(struct kiocb *kiocb, bool spin) -{ - struct request_queue *q = READ_ONCE(kiocb->private); - - if (!q) - return 0; - return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin); -} -EXPORT_SYMBOL_GPL(iomap_dio_iopoll); - -static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, - struct bio *bio) -{ - atomic_inc(&dio->ref); - - if (dio->iocb->ki_flags & IOCB_HIPRI) - bio_set_polled(bio, dio->iocb); - - dio->submit.last_queue = bdev_get_queue(iomap->bdev); - dio->submit.cookie = submit_bio(bio); -} - -static ssize_t iomap_dio_complete(struct iomap_dio *dio) -{ - struct kiocb *iocb = dio->iocb; - struct inode *inode = file_inode(iocb->ki_filp); - loff_t offset = iocb->ki_pos; - ssize_t ret; - - if (dio->end_io) { - ret = dio->end_io(iocb, - dio->error ? dio->error : dio->size, - dio->flags); - } else { - ret = dio->error; - } - - 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 dio->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->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); - - inode_dio_end(file_inode(iocb->ki_filp)); - kfree(dio); - - return ret; -} - -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); -} - -/* - * 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); -} - -static 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); - - 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 (should_dirty) { - bio_check_pages_dirty(bio); - } else { - bio_release_pages(bio, false); - bio_put(bio); - } -} - -static void -iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, - unsigned len) -{ - 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->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); -} - -static loff_t -iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, - struct iomap_dio *dio, struct iomap *iomap) -{ - 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); - struct iov_iter iter; - struct bio *bio; - bool need_zeroout = false; - bool use_fua = false; - int nr_pages, ret = 0; - size_t copied = 0; - - if ((pos | length | align) & ((1 << blkbits) - 1)) - 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) && - blk_queue_fua(bdev_get_queue(iomap->bdev))) - use_fua = true; - } - - /* - * Operate on a partial iter trimmed to the extent we were called for. - * We'll update the iter in the dio once we're done with this extent. - */ - iter = *dio->submit.iter; - iov_iter_truncate(&iter, length); - - nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); - if (nr_pages <= 0) - return nr_pages; - - 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); - } - - do { - size_t n; - if (dio->error) { - iov_iter_revert(dio->submit.iter, copied); - return 0; - } - - bio = bio_alloc(GFP_KERNEL, nr_pages); - bio_set_dev(bio, iomap->bdev); - 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; - - ret = bio_iov_iter_get_pages(bio, &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) { - 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); - } - - iov_iter_advance(dio->submit.iter, n); - - dio->size += n; - pos += n; - copied += n; - - nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); - iomap_dio_submit_bio(dio, iomap, bio); - } 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(dio, iomap, pos, fs_block_size - pad); - } - return copied ? copied : ret; -} - -static loff_t -iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio) -{ - length = iov_iter_zero(length, dio->submit.iter); - dio->size += length; - 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) -{ - struct iov_iter *iter = dio->submit.iter; - size_t copied; - - BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data)); - - if (dio->flags & IOMAP_DIO_WRITE) { - loff_t size = inode->i_size; - - if (pos > size) - memset(iomap->inline_data + size, 0, pos - size); - copied = copy_from_iter(iomap->inline_data + pos, length, iter); - if (copied) { - if (pos + copied > size) - i_size_write(inode, pos + copied); - mark_inode_dirty(inode); - } - } else { - copied = copy_to_iter(iomap->inline_data + pos, length, iter); - } - dio->size += copied; - return copied; -} - -static loff_t -iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap) -{ - struct iomap_dio *dio = data; - - switch (iomap->type) { - case IOMAP_HOLE: - if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) - return -EIO; - return iomap_dio_hole_actor(length, 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); - case IOMAP_MAPPED: - return iomap_dio_bio_actor(inode, pos, length, dio, iomap); - case IOMAP_INLINE: - return iomap_dio_inline_actor(inode, pos, length, dio, iomap); - 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. - */ -ssize_t -iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, - const struct iomap_ops *ops, iomap_dio_end_io_t end_io) -{ - 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, start = pos; - loff_t end = iocb->ki_pos + count - 1, ret = 0; - unsigned int flags = IOMAP_DIRECT; - bool wait_for_completion = is_sync_kiocb(iocb); - struct blk_plug plug; - struct iomap_dio *dio; - - lockdep_assert_held(&inode->i_rwsem); - - if (!count) - return 0; - - dio = kmalloc(sizeof(*dio), GFP_KERNEL); - if (!dio) - return -ENOMEM; - - dio->iocb = iocb; - atomic_set(&dio->ref, 1); - dio->size = 0; - dio->i_size = i_size_read(inode); - dio->end_io = end_io; - dio->error = 0; - dio->flags = 0; - - dio->submit.iter = iter; - dio->submit.waiter = current; - dio->submit.cookie = BLK_QC_T_NONE; - dio->submit.last_queue = NULL; - - if (iov_iter_rw(iter) == READ) { - if (pos >= dio->i_size) - goto out_free_dio; - - if (iter_is_iovec(iter) && iov_iter_rw(iter) == READ) - dio->flags |= IOMAP_DIO_DIRTY; - } else { - flags |= IOMAP_WRITE; - dio->flags |= IOMAP_DIO_WRITE; - - /* for data sync or sync, we need sync completion processing */ - if (iocb->ki_flags & IOCB_DSYNC) - 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; - } - - if (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_has_page(mapping, start, end)) { - ret = -EAGAIN; - goto out_free_dio; - } - flags |= IOMAP_NOWAIT; - } - - ret = filemap_write_and_wait_range(mapping, start, 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, - start >> 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) - 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; - - if (iov_iter_rw(iter) == READ && pos >= dio->i_size) - break; - } while ((count = iov_iter_count(iter)) > 0); - blk_finish_plug(&plug); - - 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->ki_cookie, dio->submit.cookie); - WRITE_ONCE(iocb->private, dio->submit.last_queue); - - /* - * 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: - * - * (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 -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(); - } - __set_current_state(TASK_RUNNING); - } - - return iomap_dio_complete(dio); - -out_free_dio: - kfree(dio); - return ret; -} -EXPORT_SYMBOL_GPL(iomap_dio_rw); diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile index 5dfe8b5cf330..a67a97758858 100644 --- a/fs/iomap/Makefile +++ b/fs/iomap/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_FS_IOMAP) += iomap.o iomap-y += \ + direct-io.o \ fiemap.o \ seek.o diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c new file mode 100644 index 000000000000..10517cea9682 --- /dev/null +++ b/fs/iomap/direct-io.c @@ -0,0 +1,562 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2010 Red Hat, Inc. + * Copyright (c) 2016-2018 Christoph Hellwig. + */ +#include <linux/module.h> +#include <linux/compiler.h> +#include <linux/fs.h> +#include <linux/iomap.h> +#include <linux/backing-dev.h> +#include <linux/uio.h> +#include <linux/task_io_accounting_ops.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; + iomap_dio_end_io_t *end_io; + loff_t i_size; + loff_t size; + atomic_t ref; + unsigned flags; + int error; + bool wait_for_completion; + + union { + /* used during submission and for synchronous completion: */ + struct { + struct iov_iter *iter; + struct task_struct *waiter; + struct request_queue *last_queue; + blk_qc_t cookie; + } submit; + + /* used for aio completion: */ + struct { + struct work_struct work; + } aio; + }; +}; + +int iomap_dio_iopoll(struct kiocb *kiocb, bool spin) +{ + struct request_queue *q = READ_ONCE(kiocb->private); + + if (!q) + return 0; + return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin); +} +EXPORT_SYMBOL_GPL(iomap_dio_iopoll); + +static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, + struct bio *bio) +{ + atomic_inc(&dio->ref); + + if (dio->iocb->ki_flags & IOCB_HIPRI) + bio_set_polled(bio, dio->iocb); + + dio->submit.last_queue = bdev_get_queue(iomap->bdev); + dio->submit.cookie = submit_bio(bio); +} + +static ssize_t iomap_dio_complete(struct iomap_dio *dio) +{ + struct kiocb *iocb = dio->iocb; + struct inode *inode = file_inode(iocb->ki_filp); + loff_t offset = iocb->ki_pos; + ssize_t ret; + + if (dio->end_io) { + ret = dio->end_io(iocb, + dio->error ? dio->error : dio->size, + dio->flags); + } else { + ret = dio->error; + } + + 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 dio->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->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); + + inode_dio_end(file_inode(iocb->ki_filp)); + kfree(dio); + + return ret; +} + +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); +} + +/* + * 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); +} + +static 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); + + 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 (should_dirty) { + bio_check_pages_dirty(bio); + } else { + bio_release_pages(bio, false); + bio_put(bio); + } +} + +static void +iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, + unsigned len) +{ + 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->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); +} + +static loff_t +iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, + struct iomap_dio *dio, struct iomap *iomap) +{ + 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); + struct iov_iter iter; + struct bio *bio; + bool need_zeroout = false; + bool use_fua = false; + int nr_pages, ret = 0; + size_t copied = 0; + + if ((pos | length | align) & ((1 << blkbits) - 1)) + 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) && + blk_queue_fua(bdev_get_queue(iomap->bdev))) + use_fua = true; + } + + /* + * Operate on a partial iter trimmed to the extent we were called for. + * We'll update the iter in the dio once we're done with this extent. + */ + iter = *dio->submit.iter; + iov_iter_truncate(&iter, length); + + nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); + if (nr_pages <= 0) + return nr_pages; + + 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); + } + + do { + size_t n; + if (dio->error) { + iov_iter_revert(dio->submit.iter, copied); + return 0; + } + + bio = bio_alloc(GFP_KERNEL, nr_pages); + bio_set_dev(bio, iomap->bdev); + 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; + + ret = bio_iov_iter_get_pages(bio, &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) { + 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); + } + + iov_iter_advance(dio->submit.iter, n); + + dio->size += n; + pos += n; + copied += n; + + nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); + iomap_dio_submit_bio(dio, iomap, bio); + } 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(dio, iomap, pos, fs_block_size - pad); + } + return copied ? copied : ret; +} + +static loff_t +iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio) +{ + length = iov_iter_zero(length, dio->submit.iter); + dio->size += length; + 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) +{ + struct iov_iter *iter = dio->submit.iter; + size_t copied; + + BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data)); + + if (dio->flags & IOMAP_DIO_WRITE) { + loff_t size = inode->i_size; + + if (pos > size) + memset(iomap->inline_data + size, 0, pos - size); + copied = copy_from_iter(iomap->inline_data + pos, length, iter); + if (copied) { + if (pos + copied > size) + i_size_write(inode, pos + copied); + mark_inode_dirty(inode); + } + } else { + copied = copy_to_iter(iomap->inline_data + pos, length, iter); + } + dio->size += copied; + return copied; +} + +static loff_t +iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, + void *data, struct iomap *iomap) +{ + struct iomap_dio *dio = data; + + switch (iomap->type) { + case IOMAP_HOLE: + if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) + return -EIO; + return iomap_dio_hole_actor(length, 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); + case IOMAP_MAPPED: + return iomap_dio_bio_actor(inode, pos, length, dio, iomap); + case IOMAP_INLINE: + return iomap_dio_inline_actor(inode, pos, length, dio, iomap); + 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. + */ +ssize_t +iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, + const struct iomap_ops *ops, iomap_dio_end_io_t end_io) +{ + 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, start = pos; + loff_t end = iocb->ki_pos + count - 1, ret = 0; + unsigned int flags = IOMAP_DIRECT; + bool wait_for_completion = is_sync_kiocb(iocb); + struct blk_plug plug; + struct iomap_dio *dio; + + lockdep_assert_held(&inode->i_rwsem); + + if (!count) + return 0; + + dio = kmalloc(sizeof(*dio), GFP_KERNEL); + if (!dio) + return -ENOMEM; + + dio->iocb = iocb; + atomic_set(&dio->ref, 1); + dio->size = 0; + dio->i_size = i_size_read(inode); + dio->end_io = end_io; + dio->error = 0; + dio->flags = 0; + + dio->submit.iter = iter; + dio->submit.waiter = current; + dio->submit.cookie = BLK_QC_T_NONE; + dio->submit.last_queue = NULL; + + if (iov_iter_rw(iter) == READ) { + if (pos >= dio->i_size) + goto out_free_dio; + + if (iter_is_iovec(iter) && iov_iter_rw(iter) == READ) + dio->flags |= IOMAP_DIO_DIRTY; + } else { + flags |= IOMAP_WRITE; + dio->flags |= IOMAP_DIO_WRITE; + + /* for data sync or sync, we need sync completion processing */ + if (iocb->ki_flags & IOCB_DSYNC) + 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; + } + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (filemap_range_has_page(mapping, start, end)) { + ret = -EAGAIN; + goto out_free_dio; + } + flags |= IOMAP_NOWAIT; + } + + ret = filemap_write_and_wait_range(mapping, start, 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, + start >> 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) + 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; + + if (iov_iter_rw(iter) == READ && pos >= dio->i_size) + break; + } while ((count = iov_iter_count(iter)) > 0); + blk_finish_plug(&plug); + + 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->ki_cookie, dio->submit.cookie); + WRITE_ONCE(iocb->private, dio->submit.last_queue); + + /* + * 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: + * + * (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 -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(); + } + __set_current_state(TASK_RUNNING); + } + + return iomap_dio_complete(dio); + +out_free_dio: + kfree(dio); + return ret; +} +EXPORT_SYMBOL_GPL(iomap_dio_rw); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 1df9ea187a9a..baa1e2d31f05 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -7,6 +7,7 @@ #include <linux/mm.h> #include <linux/types.h> #include <linux/mm_types.h> +#include <linux/blkdev.h> struct address_space; struct fiemap_extent_info; @@ -69,6 +70,12 @@ struct iomap { const struct iomap_page_ops *page_ops; }; +static inline sector_t +iomap_sector(struct iomap *iomap, loff_t pos) +{ + return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; +} + /* * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare * and page_done will be called for each page written to. This only applies to |