From: Theodore Tso Subject: Re: [PATCH -V4] ext4: Fix lockdep recursive locking warning Date: Sun, 23 Nov 2008 13:32:08 -0500 Message-ID: <20081123183208.GD26473@mit.edu> References: <1227285646-16263-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20081122204625.GF9150@mit.edu> <20081123024911.GG9150@mit.edu> <20081123163349.GB17002@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: cmm@us.ibm.com, sandeen@redhat.com, linux-ext4@vger.kernel.org To: "Aneesh Kumar K.V" Return-path: Received: from BISCAYNE-ONE-STATION.MIT.EDU ([18.7.7.80]:61561 "EHLO biscayne-one-station.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884AbYKWSfj (ORCPT ); Sun, 23 Nov 2008 13:35:39 -0500 Content-Disposition: inline In-Reply-To: <20081123163349.GB17002@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun, Nov 23, 2008 at 10:03:49PM +0530, Aneesh Kumar K.V wrote: > > How about the below patch. We can have more than 2 groups in a page > depending on the page size and blocksize. So instead of using > single_depth I guess we should use the relative group number ?. That should work. The maximum number of subclasses that we can have by default is 8. With 16k pages, that will barely be enough for 1k blocksize file systems (since we lock alloc_sem for page_size/(2*fs_block_size) block groups). If we need more than that, we might be better off just locking the entire filesystem against block allocations, since after all this is a pretty rare case; it's used only when we resize or when the filesystem is getting mounted. - Ted