[PATCH 5.6 141/254] CIFS: check new file size when extending file by fallocate

[Greg Kroah-Hartman]

From: Murphy Zhou <jencce.kernel@xxxxxxxxx>

commit ef4a632ccc1c7d3fb71a5baae85b79af08b7f94b upstream.

xfstests generic/228 checks if fallocate respect RLIMIT_FSIZE.
After fallocate mode 0 extending enabled, we can hit this failure.
Fix this by check the new file size with vfs helper, return
error if file size is larger then RLIMIT_FSIZE(ulimit -f).

This patch has been tested by LTP/xfstests aginst samba and
Windows server.

Acked-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
Signed-off-by: Murphy Zhou <jencce.kernel@xxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
CC: Stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/cifs/smb2ops.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3248,6 +3248,10 @@ static long smb3_simple_falloc(struct fi
 	 * Extending the file
 	 */
 	if ((keep_size == false) && i_size_read(inode) < off + len) {
+		rc = inode_newsize_ok(inode, off + len);
+		if (rc)
+			goto out;
+
 		if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0)
 			smb2_set_sparse(xid, tcon, cfile, inode, false);