From: "Aneesh Kumar K. V" Subject: Re: [PATCH] ext4: page_cache pages over pinned in ext4_mb_free_metadata() Date: Wed, 24 Mar 2010 22:46:13 +0530 Message-ID: <87aatxd4iq.fsf@linux.vnet.ibm.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Theodore Ts'o" , Andreas Dilger , Dave Kleikamp To: jing zhang , linux-ext4 Return-path: Received: from e23smtp01.au.ibm.com ([202.81.31.143]:60145 "EHLO e23smtp01.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752873Ab0CXRQW (ORCPT ); Wed, 24 Mar 2010 13:16:22 -0400 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [202.81.31.247]) by e23smtp01.au.ibm.com (8.14.3/8.13.1) with ESMTP id o2OHEBq4006745 for ; Thu, 25 Mar 2010 04:14:11 +1100 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o2OHAF0b1212458 for ; Thu, 25 Mar 2010 04:10:15 +1100 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o2OHGJqh013798 for ; Thu, 25 Mar 2010 04:16:20 +1100 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, 24 Mar 2010 21:00:34 +0800, jing zhang wrote: > From: Jing Zhang > > Date: Wed Mar 24 20:38:48 2010 > > The function, ext4_mb_free_metadata(), is called after > ext4_mb_load_buddy(sb, block_group, &e4b); > and before > ext4_mb_release_desc(&e4b); > in the function, ext4_mb_free_blocks(), so the bd_bitmap_page and > bd_buddy_page of e4b are well managed. > > If for special purpose, page_cache_get() is issued on these two pages, > there should also be page_cache_release() issued correspondingly, or > the two pages are over pinned. release_blocks_on_commit does that. I also have a comment around that page_cache_release. > > Cc: Theodore Ts'o > Cc: Andreas Dilger > Cc: Dave Kleikamp > Signed-off-by: Jing Zhang > > --- > > --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800 > +++ ext4_mm_leak/mballoc6.c 2010-03-24 20:31:52.000000000 +0800 > @@ -4361,15 +4361,6 @@ ext4_mb_free_metadata(handle_t *handle, > new_node = &new_entry->node; > block = new_entry->start_blk; > > - if (!*n) { > - /* first free block exent. We need to > - protect buddy cache from being freed, > - * otherwise we'll refresh it from > - * on-disk bitmap and lose not-yet-available > - * blocks */ > - page_cache_get(e4b->bd_buddy_page); > - page_cache_get(e4b->bd_bitmap_page); > - } > while (*n) { > parent = *n; > entry = rb_entry(parent, struct ext4_free_data, node); -aneesh