From: Andrew Morton <akpm@linux-foundation.org>
To: Niels de Vos <ndevos@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Al Viro <viro@zeniv.linux.org.uk>,
Mikulas Patocka <mpatocka@redhat.com>,
Jeff Moyer <jmoyer@redhat.com>, "Bryn M. Reeves" <bmr@redhat.com>
Subject: Re: [PATCH v3] fs: Invalidate the cache for a parent block-device if fsync() is called for a partition
Date: Tue, 31 Jan 2012 10:58:24 -0800 [thread overview]
Message-ID: <20120131105824.c48351b6.akpm@linux-foundation.org> (raw)
In-Reply-To: <4F28102C.1070207@redhat.com>
On Tue, 31 Jan 2012 16:00:44 +0000
Niels de Vos <ndevos@redhat.com> wrote:
> On 01/26/2012 09:45 PM, Christoph Hellwig wrote:
> > On Thu, Jan 26, 2012 at 01:40:51PM -0800, Andrew Morton wrote:
> >> The Right Thing To Do here is to make the kernel behave logically and
> >> predictably, then modify the userspace tools. But if we're modifying
> >> the userspace tools then we would just change userspace to issue a
> >> BLKFLSBUF to /dev/sda and leave the kernel alone.
> >
> > The right fix is to make partition and whole disk access coherent,
> > which is fairly simply:
> >
> > - create the block device inode/mapping per gendisk, and only reference
> > count it per block_device
> > - make sure blkdev_get_block(s) applies the correct offset if used on
> > partitions
> >
>
> This surely looks like a better way to fix this issue. I am not sure yet
> how much work that would involve and if I am the right person to fix
> this. If nobody beats me to it, I might send a patch for review some
> (undefined) time later.
One concern I have with the proposal is that it would forever rule out
support of >16T devices on 32-bit machines.
At present with 64-bit sector_t and 32-bit pgoff_t, I think we'd have a
reasonable chance of supporting, say, four 8T partitions on a 32T
device. But if we were to switch the kernel from using four 4T
address_spaces (sda1-4) over to using a single 32T address_space (sda)
then we can rule it all out.
next prev parent reply other threads:[~2012-01-31 18:58 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-20 1:58 [PATCH] block: Invalidate the cache for a parent block-device Mikulas Patocka
2012-01-20 9:35 ` Niels de Vos
2012-01-23 10:38 ` [PATCH v2] fs: Invalidate the cache for a parent block-device if fsync() is called for a partition Niels de Vos
2012-01-23 16:27 ` Jeff Moyer
2012-01-23 16:46 ` Niels de Vos
2012-01-23 19:23 ` Mikulas Patocka
2012-01-23 20:04 ` Jeff Moyer
2012-01-26 10:03 ` Andrew Morton
2012-01-26 11:50 ` Niels de Vos
2012-01-26 13:33 ` [PATCH v3] " Niels de Vos
2012-01-26 21:40 ` Andrew Morton
2012-01-26 21:45 ` Christoph Hellwig
2012-01-26 21:50 ` Mikulas Patocka
2012-01-27 12:19 ` Ric Wheeler
2012-01-31 16:00 ` Niels de Vos
2012-01-31 18:58 ` Andrew Morton [this message]
2012-01-31 19:04 ` Christoph Hellwig
2012-01-31 19:32 ` Andrew Morton
2012-01-31 19:37 ` Christoph Hellwig
2012-01-31 19:48 ` Andrew Morton
2012-01-26 21:49 ` Jeff Moyer
2012-01-26 22:13 ` Mikulas Patocka
2012-01-26 22:26 ` Kernel Oops report (Android gingerbread) Fan Zhang
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