From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 9CAA929DF8 for ; Tue, 21 May 2013 17:53:39 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay1.corp.sgi.com (Postfix) with ESMTP id 70CBE8F8059 for ; Tue, 21 May 2013 15:53:36 -0700 (PDT) Received: from ipmail04.adl6.internode.on.net (ipmail04.adl6.internode.on.net [150.101.137.141]) by cuda.sgi.com with ESMTP id 7j6QGIosfI1cofGe for ; Tue, 21 May 2013 15:53:34 -0700 (PDT) Date: Wed, 22 May 2013 08:53:33 +1000 From: Dave Chinner Subject: Re: [PATCH 03/11] xfs: remote attribute read too short Message-ID: <20130521225333.GS24543@dastard> References: <1369123330-9579-1-git-send-email-david@fromorbit.com> <1369123330-9579-4-git-send-email-david@fromorbit.com> <20130521205924.GM20028@sgi.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20130521205924.GM20028@sgi.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Ben Myers Cc: xfs@oss.sgi.com On Tue, May 21, 2013 at 03:59:24PM -0500, Ben Myers wrote: > On Tue, May 21, 2013 at 06:02:02PM +1000, Dave Chinner wrote: > > From: Dave Chinner > > > > Reading a maximally size remote attribute fails when CRCs are > > enabled with this verification error: > > > > XFS (vdb): remote attribute header does not match required off/len/owner) > > > > There are two reasons for this, the first being that the > > length of the buffer being read is determined from the > > args->rmtblkcnt which doesn't take into account CRC headers. Hence > > the mapped length ends up being too short and so we need to > > calculate it directly from the value length. > > > > The second is that the byte count of valid data within a buffer is > > capped by the length of the data and so doesn't take into account > > that the buffer might be longer due to headers. Hence we need to > > calculate the data space in the buffer first before calculating the > > actual byte count of data. > > > > Signed-off-by: Dave Chinner > > --- > > fs/xfs/xfs_attr_remote.c | 15 +++++++++------ > > 1 file changed, 9 insertions(+), 6 deletions(-) > > > > diff --git a/fs/xfs/xfs_attr_remote.c b/fs/xfs/xfs_attr_remote.c > > index aad95b0..bcdc07c 100644 > > --- a/fs/xfs/xfs_attr_remote.c > > +++ b/fs/xfs/xfs_attr_remote.c > > @@ -52,9 +52,11 @@ xfs_attr3_rmt_blocks( > > struct xfs_mount *mp, > > int attrlen) > > { > > - int buflen = XFS_ATTR3_RMT_BUF_SPACE(mp, > > - mp->m_sb.sb_blocksize); > > - return (attrlen + buflen - 1) / buflen; > > + if (xfs_sb_version_hascrc(&mp->m_sb)) { > > + int buflen = XFS_ATTR3_RMT_BUF_SPACE(mp, mp->m_sb.sb_blocksize); > > + return (attrlen + buflen - 1) / buflen; > > + } > > + return XFS_B_TO_FSB(mp, attrlen); > > xfs_attr_rmtval_set, xfs_attr3_rmt_blocks, and XFS_ATTR3_RMT_BUF_SPACE all have > checks for crcs on the superblock. It's like I'm seeing stars. Sure - I'm not concerned about how efficient the code is at this point. I just want it to work correctly. If that means we check for CRC support more frequently than we need to, then that's no big deal right now. > > > } > > > > static bool > > @@ -206,8 +208,9 @@ xfs_attr_rmtval_get( > > > > while (valuelen > 0) { > > nmap = ATTR_RMTVALUE_MAPSIZE; > > + blkcnt = xfs_attr3_rmt_blocks(mp, valuelen); > > error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno, > > - args->rmtblkcnt, map, &nmap, > > + blkcnt, map, &nmap, > > Isn't blkcnt wrong on the 2nd or greater iteration of this loop? Looks like an old bug. Yes, args->rmtblkcnt is wrong on the 2nd+ loop iteration. And yes, it's an old, old bug. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs