From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Eric Paris <eparis@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Dave Chinner <david@fromorbit.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
James Morris <james.l.morris@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Stephen Smalley <sds@tycho.nsa.gov>,
"Theodore Ts'o" <tytso@mit.edu>, stable <stable@vger.kernel.org>,
Paul Moore <paul@paul-moore.com>,
LKML <linux-kernel@vger.kernel.org>,
Matthew Wilcox <matthew@wil.cx>,
xfs@oss.sgi.com
Subject: Re: [PATCH] vfs: Fix possible NULL pointer dereference in inode_permission()
Date: Fri, 10 Jan 2014 01:31:48 -0800 [thread overview]
Message-ID: <20140110093148.GA26159@infradead.org> (raw)
In-Reply-To: <20140110000642.GN10323@ZenIV.linux.org.uk>
On Fri, Jan 10, 2014 at 12:06:42AM +0000, Al Viro wrote:
> Check what XFS is doing ;-/ That's where those call_rcu() have come from.
> Sure, we can separate the simple "just do call_rcu(...->free_inode)" case
> and hit it whenever full ->free_inode is there and ->destroy_inode isn't.
> Not too pretty, but removal of tons of boilerplate might be worth doing
> that anyway. But ->destroy_inode() is still needed for cases where fs
> has its own idea of inode lifetime rules. Again, check what XFS is doing
> in that area...
Btw, I'd really love to get rid of the XFS ->destroy_inode abuse, it's
been a long time thorn in the flesh.
What's really needed there to make XFS behave more similar to everyone
else is a way for the filesystem to say: "I can't actually free this
inode right now, but I'll come back to you later". That's what we
actually do right now, except we pretend that the VFS inode gets freed,
while its memory lives on (punt intended).
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>, Paul Moore <paul@paul-moore.com>,
Matthew Wilcox <matthew@wil.cx>,
Stephen Smalley <sds@tycho.nsa.gov>,
LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
xfs@oss.sgi.com, Eric Paris <eparis@redhat.com>,
James Morris <james.l.morris@oracle.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
stable <stable@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] vfs: Fix possible NULL pointer dereference in inode_permission()
Date: Fri, 10 Jan 2014 01:31:48 -0800 [thread overview]
Message-ID: <20140110093148.GA26159@infradead.org> (raw)
In-Reply-To: <20140110000642.GN10323@ZenIV.linux.org.uk>
On Fri, Jan 10, 2014 at 12:06:42AM +0000, Al Viro wrote:
> Check what XFS is doing ;-/ That's where those call_rcu() have come from.
> Sure, we can separate the simple "just do call_rcu(...->free_inode)" case
> and hit it whenever full ->free_inode is there and ->destroy_inode isn't.
> Not too pretty, but removal of tons of boilerplate might be worth doing
> that anyway. But ->destroy_inode() is still needed for cases where fs
> has its own idea of inode lifetime rules. Again, check what XFS is doing
> in that area...
Btw, I'd really love to get rid of the XFS ->destroy_inode abuse, it's
been a long time thorn in the flesh.
What's really needed there to make XFS behave more similar to everyone
else is a way for the filesystem to say: "I can't actually free this
inode right now, but I'll come back to you later". That's what we
actually do right now, except we pretend that the VFS inode gets freed,
while its memory lives on (punt intended).
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xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2014-01-10 9:32 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-09 21:27 [PATCH] vfs: Fix possible NULL pointer dereference in inode_permission() Steven Rostedt
2014-01-09 21:42 ` Matthew Wilcox
2014-01-09 21:50 ` Steven Rostedt
2014-01-09 22:31 ` Al Viro
[not found] ` <CA+55aFzCTPYEQCPnLBi1CwmMTocVqCFiCuJ391HkVx1CMw61ug@mail.gmail.com>
2014-01-09 23:10 ` Paul E. McKenney
2014-01-09 23:25 ` Steven Rostedt
2014-01-09 23:27 ` Steven Rostedt
2014-01-09 23:37 ` Eric Paris
2014-01-09 23:45 ` Steven Rostedt
2014-01-09 23:53 ` Linus Torvalds
2014-01-10 0:06 ` Al Viro
2014-01-10 0:09 ` Al Viro
2014-01-10 0:18 ` Linus Torvalds
2014-01-10 2:36 ` James Morris
2014-01-10 9:31 ` Christoph Hellwig [this message]
2014-01-10 9:31 ` Christoph Hellwig
2014-01-10 18:14 ` Ben Myers
2014-01-10 18:14 ` Ben Myers
2014-01-11 10:32 ` Christoph Hellwig
2014-01-11 10:32 ` Christoph Hellwig
2014-01-09 23:45 ` Paul E. McKenney
2014-01-09 23:59 ` Steven Rostedt
2014-01-10 0:44 ` Paul E. McKenney
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