From: Murphy Zhou <jencce.kernel@gmail.com>
Date: Sat, 14 Mar 2020 03:38:31 +0000 (+0800)
Subject: CIFS: fiemap: do not return EINVAL if get nothing
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0f5be2f69e89613c409f89f6429bd210efcb147b;p=linux

CIFS: fiemap: do not return EINVAL if get nothing

commit 979a2665eb6c603ddce0ab374041ab101827b2e7 upstream.

If we call fiemap on a truncated file with none blocks allocated,
it makes sense we get nothing from this call. No output means
no blocks have been counted, but the call succeeded. It's a valid
response.

Simple example reproducer:
xfs_io -f 'truncate 2M' -c 'fiemap -v' /cifssch/testfile
xfs_io: ioctl(FS_IOC_FIEMAP) ["/cifssch/testfile"]: Invalid argument

Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 99420608d2ec5..76eacffb24d86 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3252,7 +3252,7 @@ static int smb3_fiemap(struct cifs_tcon *tcon,
 	if (rc)
 		goto out;
 
-	if (out_data_len < sizeof(struct file_allocated_range_buffer)) {
+	if (out_data_len && out_data_len < sizeof(struct file_allocated_range_buffer)) {
 		rc = -EINVAL;
 		goto out;
 	}