[PATCH 4.11 068/114] Do not return number of bytes written for ioctl CIFS_IOC_COPYCHUNK_FILE

[Greg Kroah-Hartman]

4.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sachin Prabhu <sprabhu@xxxxxxxxxx>

commit 7d0c234fd2e1c9ca3fa032696c0c58b1b74a9e0b upstream.

commit 620d8745b35d ("Introduce cifs_copy_file_range()") changes the
behaviour of the cifs ioctl call CIFS_IOC_COPYCHUNK_FILE. In case of
successful writes, it now returns the number of bytes written. This
return value is treated as an error by the xfstest cifs/001. Depending
on the errno set at that time, this may or may not result in the test
failing.

The patch fixes this by setting the return value to 0 in case of
successful writes.

Fixes: commit 620d8745b35d ("Introduce cifs_copy_file_range()")
Reported-by: Eryu Guan <eguan@xxxxxxxxxx>
Signed-off-by: Sachin Prabhu <sprabhu@xxxxxxxxxx>
Acked-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/cifs/ioctl.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/cifs/ioctl.c
+++ b/fs/cifs/ioctl.c
@@ -74,7 +74,8 @@ static long cifs_ioctl_copychunk(unsigne
 
 	rc = cifs_file_copychunk_range(xid, src_file.file, 0, dst_file, 0,
 					src_inode->i_size, 0);
-
+	if (rc > 0)
+		rc = 0;
 out_fput:
 	fdput(src_file);
 out_drop_write: