ceph: fscrypt_auth handling for ceph

Most fscrypt-enabled filesystems store the crypto context in an xattr,
but that's problematic for ceph as xatts are governed by the XATTR cap,
but we really want the crypto context as part of the AUTH cap.

Because of this, the MDS has added two new inode metadata fields:
fscrypt_auth and fscrypt_file. The former is used to hold the crypto
context, and the latter is used to track the real file size.

Parse new fscrypt_auth and fscrypt_file fields in inode traces. For now,
we don't use fscrypt_file, but fscrypt_auth is used to hold the fscrypt
context.

Allow the client to use a setattr request for setting the fscrypt_auth
field. Since this is not a standard setattr request from the VFS, we add
a new field to __ceph_setattr that carries ceph-specific inode attrs.

Have the set_context op do a setattr that sets the fscrypt_auth value,
and get_context just return the contents of that field (since it should
always be available).

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-and-tested-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 3c1aa99c1876..a2e85fb5aab1 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -86,6 +86,10 @@ struct ceph_mds_reply_info_in {
 	s32 dir_pin;
 	struct ceph_timespec btime;
 	struct ceph_timespec snap_btime;
+	u8 *fscrypt_auth;
+	u8 *fscrypt_file;
+	u32 fscrypt_auth_len;
+	u32 fscrypt_file_len;
 	u64 rsnaps;
 	u64 change_attr;
 };
@@ -278,6 +282,9 @@ struct ceph_mds_request {
 	struct mutex r_fill_mutex;
 
 	union ceph_mds_request_args r_args;
+
+	struct ceph_fscrypt_auth *r_fscrypt_auth;
+
 	int r_fmode;        /* file mode, if expecting cap */
 	int r_request_release_offset;
 	const struct cred *r_cred;