cifs: Fix smb2_set_path_size()

If cifs_get_writable_path() finds a writable file, smb2_compound_op()
must use that file's FID and not the COMPOUND_FID.

Cc: stable@vger.kernel.org
Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: vlendec

fs/cifs/smb2inode.c

@@ -234,15 +234,32 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		size[0] = 8; /* sizeof __le64 */
 		data[0] = ptr;
 
-		rc = SMB2_set_info_init(tcon, server,
-					&rqst[num_rqst], COMPOUND_FID,
-					COMPOUND_FID, current->tgid,
-					FILE_END_OF_FILE_INFORMATION,
-					SMB2_O_INFO_FILE, 0, data, size);
+		if (cfile) {
+			rc = SMB2_set_info_init(tcon, server,
+						&rqst[num_rqst],
+						cfile->fid.persistent_fid,
+						cfile->fid.volatile_fid,
+						current->tgid,
+						FILE_END_OF_FILE_INFORMATION,
+						SMB2_O_INFO_FILE, 0,
+						data, size);
+		} else {
+			rc = SMB2_set_info_init(tcon, server,
+						&rqst[num_rqst],
+						COMPOUND_FID,
+						COMPOUND_FID,
+						current->tgid,
+						FILE_END_OF_FILE_INFORMATION,
+						SMB2_O_INFO_FILE, 0,
+						data, size);
+			if (!rc) {
+				smb2_set_next_command(tcon, &rqst[num_rqst]);
+				smb2_set_related(&rqst[num_rqst]);
+			}
+		}
 		if (rc)
 			goto finished;
-		smb2_set_next_command(tcon, &rqst[num_rqst]);
-		smb2_set_related(&rqst[num_rqst++]);
+		num_rqst++;
 		trace_smb3_set_eof_enter(xid, ses->Suid, tcon->tid, full_path);
 		break;
 	case SMB2_OP_SET_INFO: