From: Dave Chinner <david@fromorbit.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [git pull] vfs.git - including i_mutex wrappers
Date: Sun, 24 Jan 2016 09:44:35 +1100 [thread overview]
Message-ID: <20160123224435.GI6033@dastard> (raw)
In-Reply-To: <20160123223456.GH6033@dastard>
On Sun, Jan 24, 2016 at 09:34:56AM +1100, Dave Chinner wrote:
> On Sat, Jan 23, 2016 at 02:58:54PM +0000, Al Viro wrote:
> > ->i_mutex wrappers (with small prereq in lustre), fix for too
>
> Please explain, Al?
>
> I haven't heard anything about there being i_mutex changes pending,
> and this commit says "over the coming cycle ->i_mutex will become
> rwsem". That's a complete surprise to me, and not something that
> should be done with no warning.
>
> What's the locking model? How are filesystems supposed to use it?
> Are they even allowed to use read-mode locking, and if so, what
> operations is it going to be safe to hold the lock in read mode?
>
> Why is this change considered valid now, when previously there's
> always been significant push-back to any suggestion that we should
> make the i_mutex a rwsem so we can do shared read-only access
> locking on inode operations?
FWIW, I'm not opposed to making such a locking change - I'm more
concerned about the fact I'm finding out about plans for such a
fundamental locking change from a pull request on the last day of a
merge window....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2016-01-23 22:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-23 14:58 [git pull] vfs.git - including i_mutex wrappers Al Viro
2016-01-23 22:34 ` Dave Chinner
2016-01-23 22:44 ` Dave Chinner [this message]
2016-01-23 23:09 ` Al Viro
2016-01-23 23:38 ` Al Viro
2016-01-24 0:53 ` Dave Chinner
2016-01-24 1:41 ` Al Viro
2016-01-24 7:04 ` Dave Chinner
2016-01-24 7:48 ` Al Viro
2016-01-23 23:48 ` Linus Torvalds
2016-01-24 0:26 ` Dave Chinner
2016-01-24 1:20 ` Al Viro
2016-01-24 7:17 ` Dave Chinner
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