From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id A2EF529E07 for ; Tue, 21 May 2013 15:59:25 -0500 (CDT) Date: Tue, 21 May 2013 15:59:24 -0500 From: Ben Myers Subject: Re: [PATCH 03/11] xfs: remote attribute read too short Message-ID: <20130521205924.GM20028@sgi.com> References: <1369123330-9579-1-git-send-email-david@fromorbit.com> <1369123330-9579-4-git-send-email-david@fromorbit.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1369123330-9579-4-git-send-email-david@fromorbit.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: Dave Chinner Cc: xfs@oss.sgi.com 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. > } > > 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. > XFS_BMAPI_ATTRFORK); > if (error) > return error; > @@ -227,8 +230,8 @@ xfs_attr_rmtval_get( > if (error) > return error; > > - byte_cnt = min_t(int, valuelen, BBTOB(bp->b_length)); > - byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, byte_cnt); > + byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, BBTOB(bp->b_length)); > + byte_cnt = min_t(int, valuelen, byte_cnt); And now byte_cnt reflects the number of bytes in the mapping, less the size of a header.. Reviewed-by: Ben Myers _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs