Re: [RFC PATCH v2 1/3] ceph: add support for encrypted snapshot names

[Xiubo Li <xiubli@redhat.com>]

On 3/16/22 12:19 AM, Luís Henriques wrote:
> Since filenames in encrypted directories are already encrypted and shown
> as a base64-encoded string when the directory is locked, snapshot names
> should show a similar behaviour.
>
> Signed-off-by: Luís Henriques <lhenriques@suse.de>
> ---
>   fs/ceph/inode.c | 31 +++++++++++++++++++++++++++----
>   1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 7b670e2405c1..359e29896f16 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -91,9 +91,15 @@ struct inode *ceph_new_inode(struct inode *dir, struct dentry *dentry,
>   	if (err < 0)
>   		goto out_err;
>   
> -	err = ceph_fscrypt_prepare_context(dir, inode, as_ctx);
> -	if (err)
> -		goto out_err;
> +	/*
> +	 * We'll skip setting fscrypt context for snapshots, leaving that for
> +	 * the handle_reply().
> +	 */
> +	if (ceph_snap(dir) != CEPH_SNAPDIR) {
> +		err = ceph_fscrypt_prepare_context(dir, inode, as_ctx);
> +		if (err)
> +			goto out_err;
> +	}
>   
>   	return inode;
>   out_err:
> @@ -157,6 +163,7 @@ struct inode *ceph_get_snapdir(struct inode *parent)
>   	};
>   	struct inode *inode = ceph_get_inode(parent->i_sb, vino, NULL);
>   	struct ceph_inode_info *ci = ceph_inode(inode);
> +	int ret = -ENOTDIR;
>   
>   	if (IS_ERR(inode))
>   		return inode;
> @@ -182,6 +189,22 @@ struct inode *ceph_get_snapdir(struct inode *parent)
>   	ci->i_rbytes = 0;
>   	ci->i_btime = ceph_inode(parent)->i_btime;
>   
> +	/* if encrypted, just borrow fscrypt_auth from parent */
> +	if (IS_ENCRYPTED(parent)) {
> +		struct ceph_inode_info *pci = ceph_inode(parent);
> +
> +		ci->fscrypt_auth = kmemdup(pci->fscrypt_auth,
> +					   pci->fscrypt_auth_len,
> +					   GFP_KERNEL);
> +		if (ci->fscrypt_auth) {
> +			inode->i_flags |= S_ENCRYPTED;
> +			ci->fscrypt_auth_len = pci->fscrypt_auth_len;
> +		} else {
> +			dout("Failed to alloc snapdir fscrypt_auth\n");
> +			ret = -ENOMEM;
> +			goto err;
> +		}
> +	}
>   	if (inode->i_state & I_NEW) {
>   		inode->i_op = &ceph_snapdir_iops;
>   		inode->i_fop = &ceph_snapdir_fops;
> @@ -195,7 +218,7 @@ struct inode *ceph_get_snapdir(struct inode *parent)
>   		discard_new_inode(inode);
>   	else
>   		iput(inode);
> -	return ERR_PTR(-ENOTDIR);
> +	return ERR_PTR(ret);
>   }
>   
>   const struct inode_operations ceph_file_iops = {
>
LGTM.

Reviewed-by: Xiubo Li <xiubli@redhat.com>