1 files changed, 17 insertions, 10 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 1f2e2845eb76..76748255f843 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -517,6 +517,9 @@ xfs_file_dio_aio_write(
 	}
 
 	if (iocb->ki_flags & IOCB_NOWAIT) {
+		/* unaligned dio always waits, bail */
+		if (unaligned_io)
+			return -EAGAIN;
 		if (!xfs_ilock_nowait(ip, iolock))
 			return -EAGAIN;
 	} else {
@@ -529,18 +532,14 @@ xfs_file_dio_aio_write(
 	count = iov_iter_count(from);
 
 	/*
-	 * If we are doing unaligned IO, wait for all other IO to drain,
-	 * otherwise demote the lock if we had to take the exclusive lock
-	 * for other reasons in xfs_file_aio_write_checks.
+	 * 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.
 	 */
 	if (unaligned_io) {
-		/* If we are going to wait for other DIO to finish, bail */
-		if (iocb->ki_flags & IOCB_NOWAIT) {
-			if (atomic_read(&inode->i_dio_count))
-				return -EAGAIN;
-		} else {
-			inode_dio_wait(inode);
-		}
+		inode_dio_wait(inode);
 	} else if (iolock == XFS_IOLOCK_EXCL) {
 		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
 		iolock = XFS_IOLOCK_SHARED;
@@ -548,6 +547,14 @@ xfs_file_dio_aio_write(
 
 	trace_xfs_file_direct_write(ip, count, iocb->ki_pos);
 	ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, xfs_dio_write_end_io);
+
+	/*
+	 * If unaligned, this is the only IO in-flight. If it has not yet
+	 * completed, wait on it before we release the iolock to prevent
+	 * subsequent overlapping IO.
+	 */
+	if (ret == -EIOCBQUEUED && unaligned_io)
+		inode_dio_wait(inode);
 out:
 	xfs_iunlock(ip, iolock);