From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Paris Subject: Re: [PATCH v1.2 0/5] IMA: making i_readcount a first class inode citizen Date: Tue, 02 Nov 2010 14:03:29 -0400 Message-ID: <1288721009.3047.16.camel@localhost.localdomain> References: <1288717707-5295-1-git-send-email-zohar@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, jmorris@namei.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, Dave Chinner To: Mimi Zohar Return-path: Received: from mx1.redhat.com ([209.132.183.28]:17894 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752653Ab0KBSDr (ORCPT ); Tue, 2 Nov 2010 14:03:47 -0400 In-Reply-To: <1288717707-5295-1-git-send-email-zohar@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, 2010-11-02 at 13:08 -0400, Mimi Zohar wrote: > Changelog: > - renamed iget/iput_readcount to i_readcount_inc/dec (Dave Chinner's suggestion) > - finished cleaning up the locking, so that: (based on Eric's comment.) > - i_lock is not required > - i_mutex is taken when making measurement decisions to prevent > file metadata(eg. permissions, xattr) changing from under it. > - iint->mutex is taken when accessing/modifying the iint structure. > - Based on the previous posting discussion, i_readcount is now defined as > atomic. > > This patchset separates the incrementing/decrementing of the i_readcount, > in the VFS layer, from other IMA functionality, by replacing the current > ima_counts_get() call with i_readcount_inc(). Its unclear whether this > call to increment i_readcount should be made earlier, like i_writecount. > > The patch ordering is a bit redundant in order to leave removing the ifdef > around i_readcount until the last patch. The first four patches: redefines > i_readcount as atomic, defines i_readcount_inc/dec(), moves the IMA > functionality in ima_counts_get() to ima_file_check(), and removes the > IMA imbalance code, simplifying IMA. The last patch removes the ifdef > around i_readcount, making i_readcount into a "first class inode citizen". > > The generic_setlease code could then take advantage of i_readcount. > > Mimi > Mimi Zohar (5): > IMA: convert i_readcount to atomic > IMA: define readcount functions > IMA: maintain i_readcount in the VFS layer > IMA: remove IMA imbalance checking > IMA: making i_readcount a first class inode citizen Ack on patches 1-4. Patch 5 I'm not so sure about. As long as IMA is the only user I don't think we really want to unconditionally compile i_readcount in. I say we either leave it wrapped in CONFIG_IMA until there is a second user. Then we either unconditionally compile it in, or we wrap it in something that either user can select in the Kconfig. I'll let others voice their opinion. -Eric