[fscrypt][RFC PATCH v2] ceph: don't allow changing layout on encrypted files/directories

[Luis Henriques]

Encryption is currently only supported on files/directories with layouts
where stripe_count=1.  Forbid changing layouts when encryption is involved.

Signed-off-by: Luis Henriques <lhenriques@xxxxxxx>
---
Changes since v1:
- dropped changes to ceph_sync_setxattr(), MDS shall be responsible for
  preventing layout changes on encrypted dirs/files

 fs/ceph/ioctl.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
index 477ecc667aee..480d18bb2ff0 100644
--- a/fs/ceph/ioctl.c
+++ b/fs/ceph/ioctl.c
@@ -294,6 +294,10 @@ static long ceph_set_encryption_policy(struct file *file, unsigned long arg)
 	struct inode *inode = file_inode(file);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 
+	/* encrypted directories can't have striped layout */
+	if (ci->i_layout.stripe_count > 1)
+		return -EINVAL;
+
 	ret = vet_mds_for_fscrypt(file);
 	if (ret)
 		return ret;