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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <20201208003117.342047-4-krisman@collabora.com>
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To:     Gabriel Krisman Bertazi <krisman@collabora.com>
Cc:     dhowells@redhat.com, viro@zeniv.linux.org.uk, tytso@mit.edu,
        khazhy@google.com, adilger.kernel@dilger.ca,
        linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        kernel@collabora.com
Subject: Re: [PATCH 3/8] watch_queue: Support a text field at the end of the notification
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Date:   Tue, 08 Dec 2020 12:57:03 +0000
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Gabriel Krisman Bertazi <krisman@collabora.com> wrote:

> This allow notifications to send text information to userspace without
> having to copy it to a temporary buffer to then copy to the ring.  One
> use case to pass text information in notifications is for error
> reporting, where more debug information might be needed, but we don't
> want to explode the number of subtypes of notifications.  For instance,
> ext4 can have a single inode error notification subtype, and pass more
> information on the cause of the error in this field.

I'm generally okay with this, but you really need to note that if you make use
of this for a subtype, you don't get to add more fields for that subtype
unless there's an offset to it.

Speaking of that, you need to update:

	Documentation/watch_queue.rst

since you're changing the API.

The "Watch Sources" section will also need altering to indicate that
superblock events are now a thing.

David