ceph: voluntarily drop Ax cap for requests that create new inode

MDS need to rdlock directory inode's authlock when handling these
requests. Voluntarily dropping CEPH_CAP_AUTH_EXCL avoids a cap revoke
message.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 8a52666..3a60d11 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -835,7 +835,7 @@
 	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 	req->r_args.mknod.mode = cpu_to_le32(mode);
 	req->r_args.mknod.rdev = cpu_to_le32(rdev);
-	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 	if (acls.pagelist) {
 		req->r_pagelist = acls.pagelist;
@@ -887,7 +887,7 @@
 	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 	req->r_dentry = dget(dentry);
 	req->r_num_caps = 2;
-	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 	err = ceph_mdsc_do_request(mdsc, dir, req);
 	if (!err && !req->r_reply_info.head->is_dentry)
@@ -936,7 +936,7 @@
 	req->r_parent = dir;
 	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 	req->r_args.mkdir.mode = cpu_to_le32(mode);
-	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_AUTH_EXCL;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 	if (acls.pagelist) {
 		req->r_pagelist = acls.pagelist;