Re: [RFC PATCH v6 20/20] ceph: add fscrypt ioctls

From: Luis Henriques <lhenriques@suse.de>
To: Jeff Layton <jlayton@kernel.org>
Cc: ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-fscrypt@vger.kernel.org
Subject: Re: [RFC PATCH v6 20/20] ceph: add fscrypt ioctls
Date: Mon, 19 Apr 2021 11:09:12 +0100	[thread overview]
Message-ID: <87lf9emvqv.fsf@suse.de> (raw)
In-Reply-To: <20210413175052.163865-21-jlayton@kernel.org> (Jeff Layton's message of "Tue, 13 Apr 2021 13:50:52 -0400")

Hi Jeff!

Jeff Layton <jlayton@kernel.org> writes:
<...>
> +
> +	case FS_IOC_ADD_ENCRYPTION_KEY:
> +		ret = vet_mds_for_fscrypt(file);
> +		if (ret)
> +			return ret;
> +		atomic_inc(&ci->i_shared_gen);

After spending some (well... a lot, actually) time looking at the MDS code
to try to figure out my bug, I'm back at this point in the kernel client
code.  I understand that this code is trying to invalidate the directory
dentries here.  However, I just found that the directory we get at this
point is the filesystem root directory, and not the directory we're trying
to unlock.

So, I still don't fully understand the issue I'm seeing, but I believe the
code above is assuming 'ci' is the inode being unlocked, which isn't
correct.

(Note: I haven't checked if there are other ioctls getting the FS root.)

Cheers,
-- 
Luis