From: Dave Chinner <david@fromorbit.com>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: linux-xfs@vger.kernel.org, fstests@vger.kernel.org, amir73il@gmail.com
Subject: Re: [PATCH 5/6] xfs_io: make various commands one-shot only
Date: Fri, 16 Dec 2016 11:53:26 +1100 [thread overview]
Message-ID: <20161216005326.GK4326@dastard> (raw)
In-Reply-To: <fec1a6dd-cebd-1ff4-e916-f696139b876e@sandeen.net>
On Thu, Dec 15, 2016 at 12:21:43PM -0600, Eric Sandeen wrote:
> On 12/6/16 9:47 PM, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > It makes no sense to iterate the file table for some xfs_io
> > commands. Some commands are already marked in this way, but lots of
> > them are not and this leads to bad behaviour. For example, the open
> > command will run until the process fd table is full and EMFILE is
> > returned rather than just opening the specified file once.
>
> Ok, I'm not quite clear on when we should expect commands to be
> "oneshot"
>
> With freeze, for example, this:
>
> xfs_io -x -c freeze mnt/file mnt2/file
>
> will freeze both filesystems today. With this change,
xfs_freeze will ignore multiple filesystem options, so it only ever
passes a single file to xfs_io. IOWs, it's behaviour will be
completely unchanged by making the xfs_io freeze command a one-shot
command.
And right now, I think that's the only case we have to care about.
unless someone is actually using xfs_io directly to freeze multiple
filesystems like this, then I think it's better to make it a
one-shot command.
> xfs_io -x -c freeze mnt/file mnt2/file
>
> freezes the mnt2 filesystem but not mnt. Is that desired?
It's exactly what the man page says the freeze command does.
> I guess the command /is/ documented as "freeze fs of /current/ file"
> but i wonder if that's just an accident of documentation.
If the man page documents it as operating on the current file,
but instead it freezes all the open files, then that's a bug that
needs fixing.
> ditto for i.e. the inode command, or resblks - why not
> iterate those?
Because they are aimed at single, specific filesystem operations
only. It just doesn't make sense to iterate them across all open
files inside xfs_io. If you have multiple filesystems youneed to
query/modify, then do an xfs_io call for each.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2016-12-16 0:59 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 3:47 [PATCH 0/6] xfs_io: fix up command iteration Dave Chinner
2016-12-07 3:47 ` [PATCH 1/6] libxcmd: check CMD_FLAG_GLOBAL inside args_command() Dave Chinner
2016-12-07 3:47 ` [PATCH 2/6] libxcmd: rename args_command to command_iterator Dave Chinner
2016-12-07 3:47 ` [PATCH 3/6] libxcmd: merge command() and iterate_command() Dave Chinner
2016-12-07 3:47 ` [PATCH 4/6] libxcmd: don't check generic library commands Dave Chinner
2016-12-07 3:47 ` [PATCH 5/6] xfs_io: make various commands one-shot only Dave Chinner
2016-12-15 18:21 ` Eric Sandeen
2016-12-16 0:53 ` Dave Chinner [this message]
2016-12-16 1:50 ` Eric Sandeen
2016-12-16 4:21 ` Dave Chinner
2016-12-07 3:47 ` [PATCH 6/6] libxcmd: add non-iterating user commands Dave Chinner
2016-12-07 4:49 ` Amir Goldstein
2016-12-07 4:57 ` Amir Goldstein
2016-12-07 14:21 ` Amir Goldstein
2016-12-07 20:16 ` Dave Chinner
2016-12-08 10:14 ` Amir Goldstein
2016-12-08 22:22 ` Dave Chinner
2016-12-15 19:09 ` Eric Sandeen
2017-01-12 5:14 ` [PATCH 0/6] xfs_io: fix up command iteration Amir Goldstein
2017-01-12 12:52 ` Eric Sandeen
-- strict thread matches above, loose matches on Subject: below --
2016-12-16 4:41 [PATCH v2 " Dave Chinner
2016-12-16 4:41 ` [PATCH 5/6] xfs_io: make various commands one-shot only Dave Chinner
2016-12-20 8:44 ` Christoph Hellwig
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