Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932359Ab2JEL6H (ORCPT ); Fri, 5 Oct 2012 07:58:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50549 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932334Ab2JEL6D (ORCPT ); Fri, 5 Oct 2012 07:58:03 -0400 Message-ID: <506ECB8F.80509@redhat.com> Date: Fri, 05 Oct 2012 07:59:11 -0400 From: Brian Foster User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120911 Thunderbird/15.0.1 MIME-Version: 1.0 To: Ben Hutchings CC: Theodore Tso , Willy Tarreau , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Greg Kroah-Hartman Subject: Re: [ 110/180] ext4: dont let i_reserved_meta_blocks go negative References: <6a854f579a99b4fe2efaca1057e8ae22@local> <20121001225202.266707400@1wt.eu> <20121004215528.GK13292@decadent.org.uk> In-Reply-To: <20121004215528.GK13292@decadent.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2232 Lines: 57 On 10/04/2012 05:55 PM, Ben Hutchings wrote: > On Tue, Oct 02, 2012 at 12:53:47AM +0200, Willy Tarreau wrote: >> 2.6.32-longterm review patch. If anyone has any objections, please let me know. >> >> ------------------ >> >> From: Brian Foster >> >> commit 97795d2a5b8d3c8dc4365d4bd3404191840453ba upstream. >> >> If we hit a condition where we have allocated metadata blocks that >> were not appropriately reserved, we risk underflow of >> ei->i_reserved_meta_blocks. In turn, this can throw >> sbi->s_dirtyclusters_counter significantly out of whack and undermine >> the nondelalloc fallback logic in ext4_nonda_switch(). Warn if this >> occurs and set i_allocated_meta_blocks to avoid this problem. >> >> This condition is reproduced by xfstests 270 against ext2 with >> delalloc enabled: >> >> Mar 28 08:58:02 localhost kernel: [ 171.526344] EXT4-fs (loop1): delayed block allocation failed for inode 14 at logical offset 64486 with max blocks 64 with error -28 >> Mar 28 08:58:02 localhost kernel: [ 171.526346] EXT4-fs (loop1): This should not happen!! Data will be lost >> >> 270 ultimately fails with an inconsistent filesystem and requires an >> fsck to repair. The cause of the error is an underflow in >> ext4_da_update_reserve_space() due to an unreserved meta block >> allocation. > [...] >> + if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks)) { >> + ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, allocated %d " >> + "with only %d reserved metadata blocks\n", __func__, >> + inode->i_ino, ei->i_allocated_meta_blocks, >> + ei->i_reserved_meta_blocks); >> + WARN_ON(1); >> + ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks; >> + } > [...] > > This seems to be working around a bug elsewhere. Has the underlying > bug been fixed in mainline yet? > Yes, the bug was fixed in: 03179fe92318e7934c180d96f12eff2cb36ef7b6 ext4: undo ext4_calc_metadata_amount if we fail to claim space Brian > Ben. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/