[PATCH 5.4 42/51] xfs: fix IOCB_NOWAIT handling in xfs_file_dio_aio_read

[Greg Kroah-Hartman]

From: Christoph Hellwig <hch@xxxxxx>

commit 7b53b868a1812a9a6ab5e69249394bd37f29ce2c upstream.

Direct I/O reads can also be used with RWF_NOWAIT & co.  Fix the inode
locking in xfs_file_dio_aio_read to take IOCB_NOWAIT into account.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Acked-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Signed-off-by: Chandan Babu R <chandan.babu@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/xfs/xfs_file.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -187,7 +187,12 @@ xfs_file_dio_aio_read(
 
 	file_accessed(iocb->ki_filp);
 
-	xfs_ilock(ip, XFS_IOLOCK_SHARED);
+	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_iomap_ops, NULL);
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);