From: Chris Mason <clm@fb.com>
To: Martin Kepplinger <martink@posteo.de>
Cc: <linux-btrfs@vger.kernel.org>, <gregkh@linuxfoundation.org>,
<linux-kernel@vger.kernel.org>,
Martin Kepplinger <martink@posteo.de>
Subject: Re: [PATCH] btrfs: Don't check for file->private_data on open(). It is set by the core.
Date: Wed, 12 Nov 2014 12:59:33 -0500 [thread overview]
Message-ID: <1415815173.25389.2@mail.thefacebook.com> (raw)
In-Reply-To: <1415810308-24243-1-git-send-email-martink@posteo.de>
On Wed, Nov 12, 2014 at 11:38 AM, Martin Kepplinger <martink@posteo.de>
wrote:
> The miscdevice core now sets file->private_data to the struct
> miscdevice
> so don't fail when this is not NULL.
>
> Signed-off-by: Martin Kepplinger <martink@posteo.de>
> ---
> This is a question: what does this check provide and does overwriting
> file->private_data make any difference?
>
> Is miscdevice's open() by the user not allowed here, if
> file->private_data
> is set?
>
> thanks!!
Btrfs uses this in the transaction start ioctl to record the
transaction handle being started. Ceph is the main user of the ioctl,
and we could setup a hash table if needed. But which call path in
miscdevice is doing this?
With your patch in place, btrfs would end up overwriting the miscdevice
private_data field, which would probably cause problems.
-chris
next prev parent reply other threads:[~2014-11-12 18:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-12 16:38 [PATCH] btrfs: Don't check for file->private_data on open(). It is set by the core Martin Kepplinger
2014-11-12 17:59 ` Chris Mason [this message]
2014-11-12 18:34 ` Martin Kepplinger
2014-11-13 22:14 ` Al Viro
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