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From: "Theodore Ts'o" <tytso@mit.edu>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-fsdevel@vger.kernel.org,
	Ext4 Developers List <linux-ext4@vger.kernel.org>,
	xfs@oss.sgi.com, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 1/4] fs: split update_time() into update_time() and write_time()
Date: Mon, 24 Nov 2014 10:56:58 -0500	[thread overview]
Message-ID: <20141124155658.GA31339@thunk.org> (raw)
In-Reply-To: <20141124152101.GA12575@infradead.org>

On Mon, Nov 24, 2014 at 07:21:01AM -0800, Christoph Hellwig wrote:
> On Fri, Nov 21, 2014 at 02:59:21PM -0500, Theodore Ts'o wrote:
> > We needed to preserve update_time() because btrfs wants to have a
> > special btrfs_root_readonly() check; otherwise we could drop the
> > update_time() inode operation entirely.
> 
> Can't btrfs just set the immutable flag on every inode that is read
> when the root has the BTRFS_ROOT_SUBVOL_RDONLY flag?  That would
> cut down the places that need this check to the ioctl path so that
> we prevent users from clearling the immutable flag.

Sounds like a good plan to me, although I'm not sure I understand how
BTRFS_ROOT_SUBVOL_RDONLY flag works, since I would have thought there
are all sorts of places in the VFS layer where it is currently
checking MS_RDONLY and MNT_READONLY and _not_ checking
BTRFS_ROOT_SUBVOL_RDONLY isn't causing other problems.

But unless there's something more subtle going on, it would seem to me
that setting the immutable flag on each inode would be a better way to
go in any case.

					- Ted

WARNING: multiple messages have this Message-ID (diff)
From: Theodore Ts'o <tytso@mit.edu>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-fsdevel@vger.kernel.org,
	Ext4 Developers List <linux-ext4@vger.kernel.org>,
	linux-btrfs@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: [PATCH 1/4] fs: split update_time() into update_time() and write_time()
Date: Mon, 24 Nov 2014 10:56:58 -0500	[thread overview]
Message-ID: <20141124155658.GA31339@thunk.org> (raw)
In-Reply-To: <20141124152101.GA12575@infradead.org>

On Mon, Nov 24, 2014 at 07:21:01AM -0800, Christoph Hellwig wrote:
> On Fri, Nov 21, 2014 at 02:59:21PM -0500, Theodore Ts'o wrote:
> > We needed to preserve update_time() because btrfs wants to have a
> > special btrfs_root_readonly() check; otherwise we could drop the
> > update_time() inode operation entirely.
> 
> Can't btrfs just set the immutable flag on every inode that is read
> when the root has the BTRFS_ROOT_SUBVOL_RDONLY flag?  That would
> cut down the places that need this check to the ioctl path so that
> we prevent users from clearling the immutable flag.

Sounds like a good plan to me, although I'm not sure I understand how
BTRFS_ROOT_SUBVOL_RDONLY flag works, since I would have thought there
are all sorts of places in the VFS layer where it is currently
checking MS_RDONLY and MNT_READONLY and _not_ checking
BTRFS_ROOT_SUBVOL_RDONLY isn't causing other problems.

But unless there's something more subtle going on, it would seem to me
that setting the immutable flag on each inode would be a better way to
go in any case.

					- Ted

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  reply	other threads:[~2014-11-24 15:57 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-21 19:59 [PATCH 0/4] add support for a lazytime mount option Theodore Ts'o
2014-11-21 19:59 ` Theodore Ts'o
2014-11-21 19:59 ` [PATCH 1/4] fs: split update_time() into update_time() and write_time() Theodore Ts'o
2014-11-21 19:59   ` Theodore Ts'o
2014-11-21 20:08   ` Chris Mason
2014-11-21 20:08     ` Chris Mason
2014-11-21 21:42     ` Theodore Ts'o
2014-11-21 21:42       ` Theodore Ts'o
2014-11-24 16:38       ` David Sterba
2014-11-24 16:38         ` David Sterba
2014-11-24 17:22         ` Theodore Ts'o
2014-11-24 17:22           ` Theodore Ts'o
2014-11-24 18:09           ` David Sterba
2014-11-24 18:09             ` David Sterba
2014-11-24 15:21   ` Christoph Hellwig
2014-11-24 15:21     ` Christoph Hellwig
2014-11-24 15:56     ` Theodore Ts'o [this message]
2014-11-24 15:56       ` Theodore Ts'o
2014-11-24 17:34     ` David Sterba
2014-11-24 17:34       ` David Sterba
2014-11-25 15:51       ` David Sterba
2014-11-25 15:51         ` David Sterba
2014-11-25 17:01         ` Christoph Hellwig
2014-11-21 19:59 ` [PATCH 2/4] vfs: add support for a lazytime mount option Theodore Ts'o
2014-11-21 19:59   ` Theodore Ts'o
2014-11-25  1:52   ` Dave Chinner
2014-11-25  1:52     ` Dave Chinner
2014-11-25  4:33     ` Theodore Ts'o
2014-11-25  4:33       ` Theodore Ts'o
2014-11-25 15:32       ` Boaz Harrosh
2014-11-25 15:32         ` Boaz Harrosh
2014-11-25 17:19       ` Jan Kara
2014-11-25 17:19         ` Jan Kara
2014-11-25 17:57         ` Theodore Ts'o
2014-11-25 17:57           ` Theodore Ts'o
2014-11-25 20:18           ` Jan Kara
2014-11-25 20:18             ` Jan Kara
2014-11-25 17:30       ` Jan Kara
2014-11-25 17:30         ` Jan Kara
2014-11-25 19:26         ` Theodore Ts'o
2014-11-25 19:26           ` Theodore Ts'o
2014-11-26  0:24       ` Dave Chinner
2014-11-26  0:24         ` Dave Chinner
2014-11-21 19:59 ` [PATCH 3/4] vfs: don't let the dirty time inodes get more than a day stale Theodore Ts'o
2014-11-21 19:59   ` Theodore Ts'o
2014-11-21 20:19   ` Andreas Dilger
2014-11-21 20:19     ` Andreas Dilger
2014-11-21 21:36     ` Theodore Ts'o
2014-11-21 21:36       ` Theodore Ts'o
2014-11-21 23:09       ` Andreas Dilger
2014-11-25  1:53   ` Dave Chinner
2014-11-25  1:53     ` Dave Chinner
2014-11-25  4:45     ` Theodore Ts'o
2014-11-25  4:45       ` Theodore Ts'o
2014-11-25 23:48       ` Dave Chinner
2014-11-25 23:48         ` Dave Chinner
2014-11-26 10:20         ` Theodore Ts'o
2014-11-26 10:20           ` Theodore Ts'o
2014-11-26 22:39           ` Dave Chinner
2014-11-26 22:39             ` Dave Chinner
2014-11-25 17:31   ` Jan Kara
2014-11-25 17:31     ` Jan Kara
2014-11-21 19:59 ` [PATCH 4/4] ext4: add support for a lazytime mount option Theodore Ts'o
2014-11-21 19:59   ` Theodore Ts'o
2014-11-25 17:34   ` Jan Kara
2014-11-25 17:34     ` Jan Kara

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