From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BEACC3B1022 for ; Wed, 8 Jul 2026 15:55:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783526113; cv=none; b=IVWNVdvxpcT+i6aY7Jt71vPQFYFTYfLegTar5YbyUUdiNqdjNkK+afX4ppFrHbgkbtq0lIatiqq40YlKNi5IctrXA6bm/MYvtu7o8Q77Hhsi+h37E1xFmaUaSuiky9m7R6HHGlFdQZDmroDkeLU3kdjet1ztzXNb6k1R2DiGgDc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783526113; c=relaxed/simple; bh=TWucN5P0Ti+W3Qif6YE00wVcOOt4TVZc4gsyZWfX5oA=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=eyNWoI5MfCPeLV8t9j8/dyVH81Hqb+cgfqSUA2S3n42hDQXffKdS5LJHCmN55vEbrjBZhBYkfg/BC++sNWkyYJm1kyY3+Lc3ajmVaCB/+IEelbxZqK4FNs6Q8m0tqnGTTPzYNd058S3I9g7u5VRsRvuUY8iNys0/2S+ydkMdnrY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=I5eIxUcR; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="I5eIxUcR" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783526110; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0/KFHgfI1XWGP945B9IcYPGes3Xdr4VTjWMSrp9BtfU=; b=I5eIxUcRvQkskR0BvG9Mats27FCRco0mZmgKZ2Jzj0IKI3l46PxMAIKxB+edtUl9WURy31 FDP/8TVXc6VeuiRL9G4APa8J85sfn6DMZm8yoaAjp1Z0UOMlwekO4K2QKNg6FLF+OSrQC7 KHx9qAvbCeMvtfC6AQaF/uGjhj8LJNo= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-651-uqPD4Yu3PFi4legkiUCjhQ-1; Wed, 08 Jul 2026 11:55:05 -0400 X-MC-Unique: uqPD4Yu3PFi4legkiUCjhQ-1 X-Mimecast-MFC-AGG-ID: uqPD4Yu3PFi4legkiUCjhQ_1783526104 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E38E91956044; Wed, 8 Jul 2026 15:55:03 +0000 (UTC) Received: from localhost (unknown [10.44.33.4]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 335E11955F7B; Wed, 8 Jul 2026 15:55:02 +0000 (UTC) From: Giuseppe Scrivano To: Miklos Szeredi Cc: linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, Amir Goldstein , Al Viro , Christian Brauner Subject: Re: [PATCH] ovl: add ioctls to retrieve layer file descriptors In-Reply-To: (Miklos Szeredi's message of "Wed, 8 Jul 2026 17:37:40 +0200") References: <20260708095831.3381978-1-gscrivan@redhat.com> <878q7l8y4y.fsf@redhat.com> <87wlv57dt1.fsf@redhat.com> Date: Wed, 08 Jul 2026 17:55:01 +0200 Message-ID: <87o6gh79yi.fsf@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Miklos Szeredi writes: > On Wed, 8 Jul 2026 at 16:32, Giuseppe Scrivano wrote: > >> Amir suggested to add that functionality when I've asked for some >> feedback before sending the patch here. I am fine to drop it if this is >> the consensus although I see its utility from user space. > > How about a completely different interface: > > int get_fd_opt(const char *name, unsigned int index, unsigned int flags); > > Enumerating layers would be as easy as passing an index stating from > zero and stopping when -ERANGE is received. > > It would work for all filesystems that use files as options. No more > fs specific ioctls. Is a new syscall really justified for such a narrow use case? On the other hand, it would cover both ioctl's I am working on right now. Regards, Giuseppe