diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 01a72f53fb5dd2607879cbe9f3383e453ffc5393..be9e3900cce8cb625a822753454c61633e7a14fc 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1942,8 +1942,8 @@ relock:
 		goto buffered;
 	}
 
-	dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops,
-			     &btrfs_dio_ops, is_sync_kiocb(iocb));
+	dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
+			     0);
 
 	btrfs_inode_unlock(inode, ilock_flags);
 
@@ -3618,8 +3618,7 @@ static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
 		return 0;
 
 	btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
-	ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
-			   is_sync_kiocb(iocb));
+	ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops, 0);
 	btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
 	return ret;
 }
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 349b27f0dda0cba64cc10575bb233b9b52de2bd4..194f5d00fa32677cf98bea1d3ea7806d0aecb067 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -74,8 +74,7 @@ static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
 		return generic_file_read_iter(iocb, to);
 	}
 
-	ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL,
-			   is_sync_kiocb(iocb));
+	ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0);
 	inode_unlock_shared(inode);
 
 	file_accessed(iocb->ki_filp);
@@ -550,7 +549,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (ilock_shared)
 		iomap_ops = &ext4_iomap_overwrite_ops;
 	ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
-			   is_sync_kiocb(iocb) || unaligned_io || extend);
+			   (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0);
 	if (ret == -ENOTBLK)
 		ret = 0;
 
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index b39b339feddc934c39f58c1374695e98aeac32de..89609c2997177a990b966c44592c40ca3745e829 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -797,9 +797,7 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
 	if (ret)
 		goto out_uninit;
 
-	ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL,
-			   is_sync_kiocb(iocb));
-
+	ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL, 0);
 	gfs2_glock_dq(gh);
 out_uninit:
 	gfs2_holder_uninit(gh);
@@ -833,8 +831,7 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
 	if (offset + len > i_size_read(&ip->i_inode))
 		goto out;
 
-	ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL,
-			   is_sync_kiocb(iocb));
+	ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL, 0);
 	if (ret == -ENOTBLK)
 		ret = 0;
 out:
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 2273120d8ed7c2f30561f10a57d91dd6e33515be..e4c258a2cefc014ed6f5eb6b95341cd1a26c1016 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -451,23 +451,22 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
 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)
 {
 	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;
+	bool wait_for_completion =
+		is_sync_kiocb(iocb) || (dio_flags & IOMAP_DIO_FORCE_WAIT);
+	unsigned int iomap_flags = IOMAP_DIRECT;
 	struct blk_plug plug;
 	struct iomap_dio *dio;
 
 	if (!count)
 		return NULL;
 
-	if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion))
-		return ERR_PTR(-EIO);
-
 	dio = kmalloc(sizeof(*dio), GFP_KERNEL);
 	if (!dio)
 		return ERR_PTR(-ENOMEM);
@@ -492,7 +491,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 		if (iter_is_iovec(iter))
 			dio->flags |= IOMAP_DIO_DIRTY;
 	} else {
-		flags |= IOMAP_WRITE;
+		iomap_flags |= IOMAP_WRITE;
 		dio->flags |= IOMAP_DIO_WRITE;
 
 		/* for data sync or sync, we need sync completion processing */
@@ -514,7 +513,14 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 			ret = -EAGAIN;
 			goto out_free_dio;
 		}
-		flags |= IOMAP_NOWAIT;
+		iomap_flags |= IOMAP_NOWAIT;
+	}
+
+	if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {
+		ret = -EAGAIN;
+		if (pos >= dio->i_size || pos + count > dio->i_size)
+			goto out_free_dio;
+		iomap_flags |= IOMAP_OVERWRITE_ONLY;
 	}
 
 	ret = filemap_write_and_wait_range(mapping, pos, end);
@@ -545,7 +551,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 
 	blk_start_plug(&plug);
 	do {
-		ret = iomap_apply(inode, pos, count, flags, ops, dio,
+		ret = iomap_apply(inode, pos, count, iomap_flags, ops, dio,
 				iomap_dio_actor);
 		if (ret <= 0) {
 			/* magic error code to fall back to buffered I/O */
@@ -629,11 +635,11 @@ 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,
-		bool wait_for_completion)
+		unsigned int dio_flags)
 {
 	struct iomap_dio *dio;
 
-	dio = __iomap_dio_rw(iocb, iter, ops, dops, wait_for_completion);
+	dio = __iomap_dio_rw(iocb, iter, ops, dops, dio_flags);
 	if (IS_ERR_OR_NULL(dio))
 		return PTR_ERR_OR_ZERO(dio);
 	return iomap_dio_complete(dio);
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5b0f93f738372dfde612437cb9fe38f78aaadbf0..39695b59dfcc927de48de2eaf94a4848ea344d7f 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -197,30 +197,42 @@ xfs_file_fsync(
 	return error;
 }
 
+static int
+xfs_ilock_iocb(
+	struct kiocb		*iocb,
+	unsigned int		lock_mode)
+{
+	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!xfs_ilock_nowait(ip, lock_mode))
+			return -EAGAIN;
+	} else {
+		xfs_ilock(ip, lock_mode);
+	}
+
+	return 0;
+}
+
 STATIC ssize_t
-xfs_file_dio_aio_read(
+xfs_file_dio_read(
 	struct kiocb		*iocb,
 	struct iov_iter		*to)
 {
 	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
-	size_t			count = iov_iter_count(to);
 	ssize_t			ret;
 
-	trace_xfs_file_direct_read(ip, count, iocb->ki_pos);
+	trace_xfs_file_direct_read(iocb, to);
 
-	if (!count)
+	if (!iov_iter_count(to))
 		return 0; /* skip atime */
 
 	file_accessed(iocb->ki_filp);
 
-	if (iocb->ki_flags & IOCB_NOWAIT) {
-		if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED))
-			return -EAGAIN;
-	} else {
-		xfs_ilock(ip, XFS_IOLOCK_SHARED);
-	}
-	ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL,
-			is_sync_kiocb(iocb));
+	ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
+	if (ret)
+		return ret;
+	ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL, 0);
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
 	return ret;
@@ -232,21 +244,16 @@ xfs_file_dax_read(
 	struct iov_iter		*to)
 {
 	struct xfs_inode	*ip = XFS_I(iocb->ki_filp->f_mapping->host);
-	size_t			count = iov_iter_count(to);
 	ssize_t			ret = 0;
 
-	trace_xfs_file_dax_read(ip, count, iocb->ki_pos);
+	trace_xfs_file_dax_read(iocb, to);
 
-	if (!count)
+	if (!iov_iter_count(to))
 		return 0; /* skip atime */
 
-	if (iocb->ki_flags & IOCB_NOWAIT) {
-		if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED))
-			return -EAGAIN;
-	} else {
-		xfs_ilock(ip, XFS_IOLOCK_SHARED);
-	}
-
+	ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
+	if (ret)
+		return ret;
 	ret = dax_iomap_rw(iocb, to, &xfs_read_iomap_ops);
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
@@ -255,21 +262,18 @@ xfs_file_dax_read(
 }
 
 STATIC ssize_t
-xfs_file_buffered_aio_read(
+xfs_file_buffered_read(
 	struct kiocb		*iocb,
 	struct iov_iter		*to)
 {
 	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
 	ssize_t			ret;
 
-	trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);
+	trace_xfs_file_buffered_read(iocb, to);
 
-	if (iocb->ki_flags & IOCB_NOWAIT) {
-		if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED))
-			return -EAGAIN;
-	} else {
-		xfs_ilock(ip, XFS_IOLOCK_SHARED);
-	}
+	ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
+	if (ret)
+		return ret;
 	ret = generic_file_read_iter(iocb, to);
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
@@ -293,9 +297,9 @@ xfs_file_read_iter(
 	if (IS_DAX(inode))
 		ret = xfs_file_dax_read(iocb, to);
 	else if (iocb->ki_flags & IOCB_DIRECT)
-		ret = xfs_file_dio_aio_read(iocb, to);
+		ret = xfs_file_dio_read(iocb, to);
 	else
-		ret = xfs_file_buffered_aio_read(iocb, to);
+		ret = xfs_file_buffered_read(iocb, to);
 
 	if (ret > 0)
 		XFS_STATS_ADD(mp, xs_read_bytes, ret);
@@ -310,7 +314,7 @@ xfs_file_read_iter(
  * if called for a direct write beyond i_size.
  */
 STATIC ssize_t
-xfs_file_aio_write_checks(
+xfs_file_write_checks(
 	struct kiocb		*iocb,
 	struct iov_iter		*from,
 	int			*iolock)
@@ -328,7 +332,14 @@ restart:
 	if (error <= 0)
 		return error;
 
-	error = xfs_break_layouts(inode, iolock, BREAK_WRITE);
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		error = break_layout(inode, false);
+		if (error == -EWOULDBLOCK)
+			error = -EAGAIN;
+	} else {
+		error = xfs_break_layouts(inode, iolock, BREAK_WRITE);
+	}
+
 	if (error)
 		return error;
 
@@ -339,7 +350,11 @@ restart:
 	if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {
 		xfs_iunlock(ip, *iolock);
 		*iolock = XFS_IOLOCK_EXCL;
-		xfs_ilock(ip, *iolock);
+		error = xfs_ilock_iocb(iocb, *iolock);
+		if (error) {
+			*iolock = 0;
+			return error;
+		}
 		goto restart;
 	}
 	/*
@@ -361,6 +376,10 @@ restart:
 	isize = i_size_read(inode);
 	if (iocb->ki_pos > isize) {
 		spin_unlock(&ip->i_flags_lock);
+
+		if (iocb->ki_flags & IOCB_NOWAIT)
+			return -EAGAIN;
+
 		if (!drained_dio) {
 			if (*iolock == XFS_IOLOCK_SHARED) {
 				xfs_iunlock(ip, *iolock);
@@ -480,122 +499,149 @@ static const struct iomap_dio_ops xfs_dio_write_ops = {
 };
 
 /*
- * xfs_file_dio_aio_write - handle direct IO writes
- *
- * Lock the inode appropriately to prepare for and issue a direct IO write.
- * By separating it from the buffered write path we remove all the tricky to
- * follow locking changes and looping.
- *
- * If there are cached pages or we're extending the file, we need IOLOCK_EXCL
- * until we're sure the bytes at the new EOF have been zeroed and/or the cached
- * pages are flushed out.
- *
- * In most cases the direct IO writes will be done holding IOLOCK_SHARED
- * allowing them to be done in parallel with reads and other direct IO writes.
- * However, if the IO is not aligned to filesystem blocks, the direct IO layer
- * needs to do sub-block zeroing and that requires serialisation against other
- * direct IOs to the same block. In this case we need to serialise the
- * submission of the unaligned IOs so that we don't get racing block zeroing in
- * the dio layer.  To avoid the problem with aio, we also need to wait for
- * outstanding IOs to complete so that unwritten extent conversion is completed
- * before we try to map the overlapping block. This is currently implemented by
- * hitting it with a big hammer (i.e. inode_dio_wait()).
- *
- * Returns with locks held indicated by @iolock and errors indicated by
- * negative return values.
+ * Handle block aligned direct I/O writes
  */
-STATIC ssize_t
-xfs_file_dio_aio_write(
+static noinline ssize_t
+xfs_file_dio_write_aligned(
+	struct xfs_inode	*ip,
 	struct kiocb		*iocb,
 	struct iov_iter		*from)
 {
-	struct file		*file = iocb->ki_filp;
-	struct address_space	*mapping = file->f_mapping;
-	struct inode		*inode = mapping->host;
-	struct xfs_inode	*ip = XFS_I(inode);
-	struct xfs_mount	*mp = ip->i_mount;
-	ssize_t			ret = 0;
-	int			unaligned_io = 0;
-	int			iolock;
-	size_t			count = iov_iter_count(from);
-	struct xfs_buftarg      *target = xfs_inode_buftarg(ip);
+	int			iolock = XFS_IOLOCK_SHARED;
+	ssize_t			ret;
 
-	/* DIO must be aligned to device logical sector size */
-	if ((iocb->ki_pos | count) & target->bt_logical_sectormask)
-		return -EINVAL;
+	ret = xfs_ilock_iocb(iocb, iolock);
+	if (ret)
+		return ret;
+	ret = xfs_file_write_checks(iocb, from, &iolock);
+	if (ret)
+		goto out_unlock;
 
 	/*
-	 * Don't take the exclusive iolock here unless the I/O is unaligned to
-	 * the file system block size.  We don't need to consider the EOF
-	 * extension case here because xfs_file_aio_write_checks() will relock
-	 * the inode as necessary for EOF zeroing cases and fill out the new
-	 * inode size as appropriate.
+	 * We don't need to hold the IOLOCK exclusively across the IO, so demote
+	 * the iolock back to shared if we had to take the exclusive lock in
+	 * xfs_file_write_checks() for other reasons.
 	 */
-	if ((iocb->ki_pos & mp->m_blockmask) ||
-	    ((iocb->ki_pos + count) & mp->m_blockmask)) {
-		unaligned_io = 1;
-
-		/*
-		 * We can't properly handle unaligned direct I/O to reflink
-		 * files yet, as we can't unshare a partial block.
-		 */
-		if (xfs_is_cow_inode(ip)) {
-			trace_xfs_reflink_bounce_dio_write(ip, iocb->ki_pos, count);
-			return -ENOTBLK;
-		}
-		iolock = XFS_IOLOCK_EXCL;
-	} else {
+	if (iolock == XFS_IOLOCK_EXCL) {
+		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
 		iolock = XFS_IOLOCK_SHARED;
 	}
+	trace_xfs_file_direct_write(iocb, from);
+	ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
+			   &xfs_dio_write_ops, 0);
+out_unlock:
+	if (iolock)
+		xfs_iunlock(ip, iolock);
+	return ret;
+}
 
-	if (iocb->ki_flags & IOCB_NOWAIT) {
-		/* unaligned dio always waits, bail */
-		if (unaligned_io)
-			return -EAGAIN;
-		if (!xfs_ilock_nowait(ip, iolock))
+/*
+ * Handle block unaligned direct I/O writes
+ *
+ * In most cases direct I/O writes will be done holding IOLOCK_SHARED, allowing
+ * them to be done in parallel with reads and other direct I/O writes.  However,
+ * if the I/O is not aligned to filesystem blocks, the direct I/O layer may need
+ * to do sub-block zeroing and that requires serialisation against other direct
+ * I/O to the same block.  In this case we need to serialise the submission of
+ * the unaligned I/O so that we don't get racing block zeroing in the dio layer.
+ * In the case where sub-block zeroing is not required, we can do concurrent
+ * sub-block dios to the same block successfully.
+ *
+ * Optimistically submit the I/O using the shared lock first, but use the
+ * IOMAP_DIO_OVERWRITE_ONLY flag to tell the lower layers to return -EAGAIN
+ * if block allocation or partial block zeroing would be required.  In that case
+ * we try again with the exclusive lock.
+ */
+static noinline ssize_t
+xfs_file_dio_write_unaligned(
+	struct xfs_inode	*ip,
+	struct kiocb		*iocb,
+	struct iov_iter		*from)
+{
+	size_t			isize = i_size_read(VFS_I(ip));
+	size_t			count = iov_iter_count(from);
+	int			iolock = XFS_IOLOCK_SHARED;
+	unsigned int		flags = IOMAP_DIO_OVERWRITE_ONLY;
+	ssize_t			ret;
+
+	/*
+	 * Extending writes need exclusivity because of the sub-block zeroing
+	 * that the DIO code always does for partial tail blocks beyond EOF, so
+	 * don't even bother trying the fast path in this case.
+	 */
+	if (iocb->ki_pos > isize || iocb->ki_pos + count >= isize) {
+retry_exclusive:
+		if (iocb->ki_flags & IOCB_NOWAIT)
 			return -EAGAIN;
-	} else {
-		xfs_ilock(ip, iolock);
+		iolock = XFS_IOLOCK_EXCL;
+		flags = IOMAP_DIO_FORCE_WAIT;
 	}
 
-	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
+	ret = xfs_ilock_iocb(iocb, iolock);
 	if (ret)
-		goto out;
-	count = iov_iter_count(from);
+		return ret;
 
 	/*
-	 * If we are doing unaligned IO, we can't allow any other overlapping IO
-	 * in-flight at the same time or we risk data corruption. Wait for all
-	 * other IO to drain before we submit. If the IO is aligned, demote the
-	 * iolock if we had to take the exclusive lock in
-	 * xfs_file_aio_write_checks() for other reasons.
+	 * We can't properly handle unaligned direct I/O to reflink files yet,
+	 * as we can't unshare a partial block.
 	 */
-	if (unaligned_io) {
-		inode_dio_wait(inode);
-	} else if (iolock == XFS_IOLOCK_EXCL) {
-		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
-		iolock = XFS_IOLOCK_SHARED;
+	if (xfs_is_cow_inode(ip)) {
+		trace_xfs_reflink_bounce_dio_write(iocb, from);
+		ret = -ENOTBLK;
+		goto out_unlock;
 	}
 
-	trace_xfs_file_direct_write(ip, count, iocb->ki_pos);
+	ret = xfs_file_write_checks(iocb, from, &iolock);
+	if (ret)
+		goto out_unlock;
+
 	/*
-	 * If unaligned, this is the only IO in-flight. Wait on it before we
-	 * release the iolock to prevent subsequent overlapping IO.
+	 * If we are doing exclusive unaligned I/O, this must be the only I/O
+	 * in-flight.  Otherwise we risk data corruption due to unwritten extent
+	 * conversions from the AIO end_io handler.  Wait for all other I/O to
+	 * drain first.
 	 */
+	if (flags & IOMAP_DIO_FORCE_WAIT)
+		inode_dio_wait(VFS_I(ip));
+
+	trace_xfs_file_direct_write(iocb, from);
 	ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
-			   &xfs_dio_write_ops,
-			   is_sync_kiocb(iocb) || unaligned_io);
-out:
-	xfs_iunlock(ip, iolock);
+			   &xfs_dio_write_ops, flags);
 
 	/*
-	 * No fallback to buffered IO after short writes for XFS, direct I/O
-	 * will either complete fully or return an error.
+	 * Retry unaligned I/O with exclusive blocking semantics if the DIO
+	 * layer rejected it for mapping or locking reasons. If we are doing
+	 * nonblocking user I/O, propagate the error.
 	 */
-	ASSERT(ret < 0 || ret == count);
+	if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) {
+		ASSERT(flags & IOMAP_DIO_OVERWRITE_ONLY);
+		xfs_iunlock(ip, iolock);
+		goto retry_exclusive;
+	}
+
+out_unlock:
+	if (iolock)
+		xfs_iunlock(ip, iolock);
 	return ret;
 }
 
+static ssize_t
+xfs_file_dio_write(
+	struct kiocb		*iocb,
+	struct iov_iter		*from)
+{
+	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
+	struct xfs_buftarg      *target = xfs_inode_buftarg(ip);
+	size_t			count = iov_iter_count(from);
+
+	/* direct I/O must be aligned to device logical sector size */
+	if ((iocb->ki_pos | count) & target->bt_logical_sectormask)
+		return -EINVAL;
+	if ((iocb->ki_pos | count) & ip->i_mount->m_blockmask)
+		return xfs_file_dio_write_unaligned(ip, iocb, from);
+	return xfs_file_dio_write_aligned(ip, iocb, from);
+}
+
 static noinline ssize_t
 xfs_file_dax_write(
 	struct kiocb		*iocb,
@@ -605,31 +651,26 @@ xfs_file_dax_write(
 	struct xfs_inode	*ip = XFS_I(inode);
 	int			iolock = XFS_IOLOCK_EXCL;
 	ssize_t			ret, error = 0;
-	size_t			count;
 	loff_t			pos;
 
-	if (iocb->ki_flags & IOCB_NOWAIT) {
-		if (!xfs_ilock_nowait(ip, iolock))
-			return -EAGAIN;
-	} else {
-		xfs_ilock(ip, iolock);
-	}
-
-	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
+	ret = xfs_ilock_iocb(iocb, iolock);
+	if (ret)
+		return ret;
+	ret = xfs_file_write_checks(iocb, from, &iolock);
 	if (ret)
 		goto out;
 
 	pos = iocb->ki_pos;
-	count = iov_iter_count(from);
 
-	trace_xfs_file_dax_write(ip, count, pos);
+	trace_xfs_file_dax_write(iocb, from);
 	ret = dax_iomap_rw(iocb, from, &xfs_direct_write_iomap_ops);
 	if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
 		i_size_write(inode, iocb->ki_pos);
 		error = xfs_setfilesize(ip, pos, ret);
 	}
 out:
-	xfs_iunlock(ip, iolock);
+	if (iolock)
+		xfs_iunlock(ip, iolock);
 	if (error)
 		return error;
 
@@ -643,7 +684,7 @@ out:
 }
 
 STATIC ssize_t
-xfs_file_buffered_aio_write(
+xfs_file_buffered_write(
 	struct kiocb		*iocb,
 	struct iov_iter		*from)
 {
@@ -662,14 +703,14 @@ write_retry:
 	iolock = XFS_IOLOCK_EXCL;
 	xfs_ilock(ip, iolock);
 
-	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
+	ret = xfs_file_write_checks(iocb, from, &iolock);
 	if (ret)
 		goto out;
 
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
 
-	trace_xfs_file_buffered_write(ip, iov_iter_count(from), iocb->ki_pos);
+	trace_xfs_file_buffered_write(iocb, from);
 	ret = iomap_file_buffered_write(iocb, from,
 			&xfs_buffered_write_iomap_ops);
 	if (likely(ret >= 0))
@@ -749,12 +790,12 @@ xfs_file_write_iter(
 		 * CoW.  In all other directio scenarios we do not
 		 * allow an operation to fall back to buffered mode.
 		 */
-		ret = xfs_file_dio_aio_write(iocb, from);
+		ret = xfs_file_dio_write(iocb, from);
 		if (ret != -ENOTBLK)
 			return ret;
 	}
 
-	return xfs_file_buffered_aio_write(iocb, from);
+	return xfs_file_buffered_write(iocb, from);
 }
 
 static void
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 7b9ff824e82d48b4040f6442426d4a0e7eacb6e4..ef76f775fabf11a4bd158cad167d31f3011437e7 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -784,15 +784,28 @@ xfs_direct_write_iomap_begin(
 		goto allocate_blocks;
 
 	/*
-	 * NOWAIT IO needs to span the entire requested IO with a single map so
-	 * that we avoid partial IO failures due to the rest of the IO range not
-	 * covered by this map triggering an EAGAIN condition when it is
-	 * subsequently mapped and aborting the IO.
+	 * NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
+	 * a single map so that we avoid partial IO failures due to the rest of
+	 * the I/O range not covered by this map triggering an EAGAIN condition
+	 * when it is subsequently mapped and aborting the I/O.
 	 */
-	if ((flags & IOMAP_NOWAIT) &&
-	    !imap_spans_range(&imap, offset_fsb, end_fsb)) {
+	if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
 		error = -EAGAIN;
-		goto out_unlock;
+		if (!imap_spans_range(&imap, offset_fsb, end_fsb))
+			goto out_unlock;
+	}
+
+	/*
+	 * For overwrite only I/O, we cannot convert unwritten extents without
+	 * requiring sub-block zeroing.  This can only be done under an
+	 * exclusive IOLOCK, hence return -EAGAIN if this is not a written
+	 * extent to tell the caller to try again.
+	 */
+	if (flags & IOMAP_OVERWRITE_ONLY) {
+		error = -EAGAIN;
+		if (imap.br_state != XFS_EXT_NORM &&
+	            ((offset | length) & mp->m_blockmask))
+			goto out_unlock;
 	}
 
 	xfs_iunlock(ip, lockmode);
@@ -801,7 +814,7 @@ xfs_direct_write_iomap_begin(
 
 allocate_blocks:
 	error = -EAGAIN;
-	if (flags & IOMAP_NOWAIT)
+	if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
 		goto out_unlock;
 
 	/*
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 5a263ae3d4f00890d6c67ed240d954afb9c36461..0cfd65cd67c1906b4dded5ce4d0f7aa7acb443ef 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1287,8 +1287,8 @@ TRACE_EVENT(xfs_log_assign_tail_lsn,
 )
 
 DECLARE_EVENT_CLASS(xfs_file_class,
-	TP_PROTO(struct xfs_inode *ip, size_t count, loff_t offset),
-	TP_ARGS(ip, count, offset),
+	TP_PROTO(struct kiocb *iocb, struct iov_iter *iter),
+	TP_ARGS(iocb, iter),
 	TP_STRUCT__entry(
 		__field(dev_t, dev)
 		__field(xfs_ino_t, ino)
@@ -1297,11 +1297,11 @@ DECLARE_EVENT_CLASS(xfs_file_class,
 		__field(size_t, count)
 	),
 	TP_fast_assign(
-		__entry->dev = VFS_I(ip)->i_sb->s_dev;
-		__entry->ino = ip->i_ino;
-		__entry->size = ip->i_d.di_size;
-		__entry->offset = offset;
-		__entry->count = count;
+		__entry->dev = file_inode(iocb->ki_filp)->i_sb->s_dev;
+		__entry->ino = XFS_I(file_inode(iocb->ki_filp))->i_ino;
+		__entry->size = XFS_I(file_inode(iocb->ki_filp))->i_d.di_size;
+		__entry->offset = iocb->ki_pos;
+		__entry->count = iov_iter_count(iter);
 	),
 	TP_printk("dev %d:%d ino 0x%llx size 0x%llx offset 0x%llx count 0x%zx",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
@@ -1313,14 +1313,16 @@ DECLARE_EVENT_CLASS(xfs_file_class,
 
 #define DEFINE_RW_EVENT(name)		\
 DEFINE_EVENT(xfs_file_class, name,	\
-	TP_PROTO(struct xfs_inode *ip, size_t count, loff_t offset),	\
-	TP_ARGS(ip, count, offset))
+	TP_PROTO(struct kiocb *iocb, struct iov_iter *iter),		\
+	TP_ARGS(iocb, iter))
 DEFINE_RW_EVENT(xfs_file_buffered_read);
 DEFINE_RW_EVENT(xfs_file_direct_read);
 DEFINE_RW_EVENT(xfs_file_dax_read);
 DEFINE_RW_EVENT(xfs_file_buffered_write);
 DEFINE_RW_EVENT(xfs_file_direct_write);
 DEFINE_RW_EVENT(xfs_file_dax_write);
+DEFINE_RW_EVENT(xfs_reflink_bounce_dio_write);
+
 
 DECLARE_EVENT_CLASS(xfs_imap_class,
 	TP_PROTO(struct xfs_inode *ip, xfs_off_t offset, ssize_t count,
@@ -3294,8 +3296,6 @@ DEFINE_INODE_IREC_EVENT(xfs_reflink_cow_found);
 DEFINE_INODE_IREC_EVENT(xfs_reflink_cow_enospc);
 DEFINE_INODE_IREC_EVENT(xfs_reflink_convert_cow);
 
-DEFINE_SIMPLE_IO_EVENT(xfs_reflink_bounce_dio_write);
-
 DEFINE_SIMPLE_IO_EVENT(xfs_reflink_cancel_cow_range);
 DEFINE_SIMPLE_IO_EVENT(xfs_reflink_end_cow);
 DEFINE_INODE_IREC_EVENT(xfs_reflink_cow_remap);
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index bec47f2d074beb1e00379cfef9940ebac238c203..0e7ab0bc00ae8e0d04b0b6e42a1077d742b46032 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -780,7 +780,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 		ret = zonefs_file_dio_append(iocb, from);
 	else
 		ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
-				   &zonefs_write_dio_ops, sync);
+				   &zonefs_write_dio_ops, 0);
 	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
 	    (ret > 0 || ret == -EIOCBQUEUED)) {
 		if (ret > 0)
@@ -917,7 +917,7 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 		}
 		file_accessed(iocb->ki_filp);
 		ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
-				   &zonefs_read_dio_ops, is_sync_kiocb(iocb));
+				   &zonefs_read_dio_ops, 0);
 	} else {
 		ret = generic_file_read_iter(iocb, to);
 		if (ret == -EIO)
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 8ebb1fa6f3b721ba9689972182ed49f826797a1c..d202fd2d0f91ed2ece4b45f2de24a155adb9abd8 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -123,6 +123,7 @@ struct iomap_page_ops {
 #define IOMAP_FAULT		(1 << 3) /* mapping for page fault */
 #define IOMAP_DIRECT		(1 << 4) /* direct I/O */
 #define IOMAP_NOWAIT		(1 << 5) /* do not block */
+#define IOMAP_OVERWRITE_ONLY	(1 << 6) /* only pure overwrites allowed */
 
 struct iomap_ops {
 	/*
@@ -257,12 +258,25 @@ struct iomap_dio_ops {
 			struct bio *bio, loff_t file_offset);
 };
 
+/*
+ * Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not
+ * synchronous.
+ */
+#define IOMAP_DIO_FORCE_WAIT	(1 << 0)
+
+/*
+ * Do not allocate blocks or zero partial blocks, but instead fall back to
+ * the caller by returning -EAGAIN.  Used to optimize direct I/O writes that
+ * are not aligned to the file system block size.
+  */
+#define IOMAP_DIO_OVERWRITE_ONLY	(1 << 1)
+
 ssize_t 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);
 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);
 ssize_t iomap_dio_complete(struct iomap_dio *dio);
 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);