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Date:   Tue, 28 Jan 2020 18:35:52 +0100
From:   David Sterba <dsterba@suse.cz>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Marcos Paulo de Souza <marcos.souza.org@gmail.com>,
        linux-kernel@vger.kernel.org, dsterba@suse.com,
        josef@toxicpanda.com, linux-btrfs@vger.kernel.org,
        Marcos Paulo de Souza <mpdesouza@suse.com>
Subject: Re: [PATCHv2] btrfs: Introduce new BTRFS_IOC_SNAP_DESTROY_V2 ioctl
Message-ID: <20200128173552.GC3929@twin.jikos.cz>
Reply-To: dsterba@suse.cz
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        Marcos Paulo de Souza <marcos.souza.org@gmail.com>,
        linux-kernel@vger.kernel.org, dsterba@suse.com,
        josef@toxicpanda.com, linux-btrfs@vger.kernel.org,
        Marcos Paulo de Souza <mpdesouza@suse.com>
References: <20200127024817.15587-1-marcos.souza.org@gmail.com>
 <20200128173100.GA16464@infradead.org>
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On Tue, Jan 28, 2020 at 09:31:00AM -0800, Christoph Hellwig wrote:
> On Sun, Jan 26, 2020 at 11:48:17PM -0300, Marcos Paulo de Souza wrote:
> > From: Marcos Paulo de Souza <mpdesouza@suse.com>
> > 
> > This ioctl will be responsible for deleting a subvolume using it's id.
> > This can be used when a system has a file system mounted from a
> > subvolume, rather than the root file system, like below:
> 
> Isn't BTRFS_IOC_SNAP_DESTROY_BY_ID a better name?

I'd prefer to keep it V2 as a more flexible ioctl than just to delete
by id. There are other _V2 ioctls that use matching
btrfs_ioctl_vol_args_v2 structure. In case we want to implement
recursive subvolume deletion we'd have to introduce yet another ioctl
number compared to just a new flag and support both by-name and by-id.
Sounds like a lot of duplication.