From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org, hch@infradead.org,
warthog9@kernel.org, jmorris@namei.org, kyle@mcmartin.ca,
hpa@zytor.com, akpm@linux-foundation.org, mingo@elte.hu,
eparis@redhat.com, viro@zeniv.linux.org.uk,
Matthew Wilcox <matthew@wil.cx>
Subject: Re: [PATCH 0/4] IMA: making i_readcount a first class inode citizen
Date: Thu, 28 Oct 2010 18:38:30 -0400 [thread overview]
Message-ID: <1288305510.2610.13.camel@localhost.localdomain> (raw)
In-Reply-To: <AANLkTimG6o66SFHskkDOtLqYeSzwKt2c0jR3CWe+sd2w@mail.gmail.com>
On Thu, 2010-10-28 at 15:29 -0700, Linus Torvalds wrote:
> On Thu, Oct 28, 2010 at 3:24 PM, Dave Chinner <david@fromorbit.com> wrote:
> >
> > Why the wrapper functions and locking? Why not an atomic variable like
> > i_writecount?
>
> Indeed. With moving this more into the VFS, let's just make sure it
> looks like i_writecount as much as possible.
>
> Linus
Would making i_readcount atomic be enough in ima_rdwr_violation_check(),
or would it still need to take the spin_lock? IMA needs guarantees
that the i_readcount/i_writecount won't be updated in between.
spin_lock(&inode->i_lock);
if (mode & FMODE_WRITE) {
if (inode->i_readcount && IS_IMA(inode))
send_tomtou = true;
goto out;
}
rc = ima_must_measure(NULL, inode, MAY_READ, FILE_CHECK);
if (rc < 0)
goto out;
if (atomic_read(&inode->i_writecount) > 0)
send_writers = true;
out:
spin_unlock(&inode->i_lock);
Wouldn't the same be true in fs/locks:get_setleases()?
Mimi
next prev parent reply other threads:[~2010-10-28 22:38 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-28 22:02 [PATCH 0/4] IMA: making i_readcount a first class inode citizen Mimi Zohar
2010-10-28 22:02 ` [PATCH 1/4] IMA: define readcount functions Mimi Zohar
2010-10-28 22:02 ` [PATCH 2/4] IMA: maintain i_readcount in the VFS layer Mimi Zohar
2010-10-29 14:13 ` Valdis.Kletnieks
2010-10-29 15:15 ` Valdis.Kletnieks
2010-10-28 22:02 ` [PATCH 3/4] IMA: remove IMA imbalance checking Mimi Zohar
2010-10-28 22:02 ` [PATCH 4/4] IMA: making i_readcount a first class inode citizen Mimi Zohar
2010-10-28 22:24 ` [PATCH 0/4] " Dave Chinner
2010-10-28 22:29 ` Linus Torvalds
2010-10-28 22:38 ` Mimi Zohar [this message]
2010-10-28 22:46 ` Linus Torvalds
2010-10-28 23:25 ` Al Viro
2010-10-28 22:45 ` Eric Paris
2010-10-29 0:30 ` Mimi Zohar
2010-11-06 10:44 ` Pavel Machek
2010-11-05 1:12 ` J. Bruce Fields
2010-11-05 11:08 ` Mimi Zohar
2010-11-05 16:28 ` J. Bruce Fields
2010-11-05 17:38 ` Mimi Zohar
2010-11-05 19:08 ` J. Bruce Fields
2010-11-05 20:58 ` J. Bruce Fields
2010-11-07 0:03 ` Mimi Zohar
-- strict thread matches above, loose matches on Subject: below --
2011-02-14 20:29 Mimi Zohar
2011-02-16 23:08 ` Mimi Zohar
2011-02-17 1:46 ` James Morris
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