[PATCH 5.12 28/45] ceph: dont clobber i_snap_caps on non-I_NEW inode

From: Greg Kroah-Hartman
Date: Thu May 20 2021 - 05:26:03 EST


From: Jeff Layton <jlayton@xxxxxxxxxx>

[ Upstream commit d3c51ae1b8cce5bdaf91a1ce32b33cf5626075dc ]

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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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;
}
--
2.30.2