From: Jeff Layton <jlayton@kernel.org>
Date: Mon, 1 Mar 2021 07:38:01 -0500
Subject: ceph: don't clobber i_snap_caps on non-I_NEW inode
Git-commit: d3c51ae1b8cce5bdaf91a1ce32b33cf5626075dc
Patch-mainline: v5.13-rc1
References: bsc#1186501

We want the snapdir to mirror the non-snapped directory's attributes for
most things, but i_snap_caps represents the caps granted on the snapshot
directory by the MDS itself. A misbehaving MDS could issue different
caps for the snapdir and we lose them here.

Only reset i_snap_caps when the inode is I_NEW. Also, move the setting
of i_op and i_fop inside the if block since they should never change
anyway.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>

---
 fs/ceph/inode.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 4418d4be2907..2fd1c48ac5d7 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -87,14 +87,15 @@ struct inode *ceph_get_snapdir(struct inode *parent)
 	inode->i_mtime = parent->i_mtime;
 	inode->i_ctime = parent->i_ctime;
 	inode->i_atime = parent->i_atime;
-	inode->i_op = &ceph_snapdir_iops;
-	inode->i_fop = &ceph_snapdir_fops;
-	ci->i_snap_caps = CEPH_CAP_PIN; /* so we can open */
 	ci->i_rbytes = 0;
 	ci->i_btime = ceph_inode(parent)->i_btime;
 
-	if (inode->i_state & I_NEW)
+	if (inode->i_state & I_NEW) {
+		inode->i_op = &ceph_snapdir_iops;
+		inode->i_fop = &ceph_snapdir_fops;
+		ci->i_snap_caps = CEPH_CAP_PIN; /* so we can open */
 		unlock_new_inode(inode);
+	}
 
 	return inode;
 }