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authorChristoph Hellwig <hch@lst.de>2017-08-29 16:13:20 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2017-09-04 19:04:23 -0400
commit91f9943e1c7b6638f27312d03fe71fcc67b23571 (patch)
treebf9c2212d93f4fbf9af6f5fafc2e667fa3d29de1 /fs/xfs/xfs_file.c
parent3239d834847627b6634a4139cf1dc58f6f137a46 (diff)
downloadlinux-91f9943e1c7b6638f27312d03fe71fcc67b23571.tar.gz
fs: support RWF_NOWAIT for buffered reads
This is based on the old idea and code from Milosz Tanski.  With the aio
nowait code it becomes mostly trivial now.  Buffered writes continue to
return -EOPNOTSUPP if RWF_NOWAIT is passed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/xfs/xfs_file.c')
-rw-r--r--fs/xfs/xfs_file.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index c4893e226fd8..1a09104b3eb0 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -259,7 +259,11 @@ xfs_file_buffered_aio_read(
 
 	trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);
 
-	xfs_ilock(ip, XFS_IOLOCK_SHARED);
+	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {
+		if (iocb->ki_flags & IOCB_NOWAIT)
+			return -EAGAIN;
+		xfs_ilock(ip, XFS_IOLOCK_SHARED);
+	}
 	ret = generic_file_read_iter(iocb, to);
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
@@ -636,6 +640,9 @@ xfs_file_buffered_aio_write(
 	int			enospc = 0;
 	int			iolock;
 
+	if (iocb->ki_flags & IOCB_NOWAIT)
+		return -EOPNOTSUPP;
+
 write_retry:
 	iolock = XFS_IOLOCK_EXCL;
 	xfs_ilock(ip, iolock);
@@ -912,7 +919,7 @@ xfs_file_open(
 		return -EFBIG;
 	if (XFS_FORCED_SHUTDOWN(XFS_M(inode->i_sb)))
 		return -EIO;
-	file->f_mode |= FMODE_AIO_NOWAIT;
+	file->f_mode |= FMODE_NOWAIT;
 	return 0;
 }