From: Alasdair G Kergon <agk@redhat.com>
To: Sandeep K Sinha <sandeepksinha@gmail.com>
Cc: dm-devel@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: Device mapper support for more than one target ?
Date: Mon, 22 Dec 2008 18:50:33 +0000 [thread overview]
Message-ID: <20081222185033.GA17119@agk.fab.redhat.com> (raw)
In-Reply-To: <37d33d830812220922l5a0bc36et5dd1f9853f9cd33@mail.gmail.com>
On Mon, Dec 22, 2008 at 10:52:08PM +0530, Sandeep K Sinha wrote:
> After looking at the complete implementation of device mappers, I
> figured out that we can have more than one target for a mapped device
> then why do we have a check for the number of target to be equal to
> one , in dm_blk_ioctl ( ) in drivers/md/dm.c
>
> http://lxr.linux.no/linux+v2.6.27.10/drivers/md/dm.c#L337
Because whether or not it makes sense to send any specific ioctl to more
than one target in parallel depends on what that ioctl does. When we
added that code we said that we could add hard-coding for specific
ioctls if the need arose, but so far it hasn't.
Alasdair
--
agk@redhat.com
WARNING: multiple messages have this Message-ID (diff)
From: Alasdair G Kergon <agk@redhat.com>
To: Sandeep K Sinha <sandeepksinha@gmail.com>
Cc: linux-kernel@vger.kernel.org, dm-devel@redhat.com
Subject: Re: Device mapper support for more than one target ?
Date: Mon, 22 Dec 2008 18:50:33 +0000 [thread overview]
Message-ID: <20081222185033.GA17119@agk.fab.redhat.com> (raw)
In-Reply-To: <37d33d830812220922l5a0bc36et5dd1f9853f9cd33@mail.gmail.com>
On Mon, Dec 22, 2008 at 10:52:08PM +0530, Sandeep K Sinha wrote:
> After looking at the complete implementation of device mappers, I
> figured out that we can have more than one target for a mapped device
> then why do we have a check for the number of target to be equal to
> one , in dm_blk_ioctl ( ) in drivers/md/dm.c
>
> http://lxr.linux.no/linux+v2.6.27.10/drivers/md/dm.c#L337
Because whether or not it makes sense to send any specific ioctl to more
than one target in parallel depends on what that ioctl does. When we
added that code we said that we could add hard-coding for specific
ioctls if the need arose, but so far it hasn't.
Alasdair
--
agk@redhat.com
next prev parent reply other threads:[~2008-12-22 18:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-22 17:22 Device mapper support for more than one target ? Sandeep K Sinha
2008-12-22 18:50 ` Alasdair G Kergon [this message]
2008-12-22 18:50 ` Alasdair G Kergon
2008-12-22 18:54 ` Sandeep K Sinha
2008-12-22 19:03 ` Sandeep K Sinha
2008-12-22 21:24 ` Alasdair G Kergon
2008-12-22 21:24 ` [dm-devel] " Alasdair G Kergon
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