xfs: remote attribute read too short (913e96bc) · Commits · 戴 / test

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 <dchinner@redhat.com> Reviewed-by:

Ben Myers <bpm@sgi.com> Signed-off-by:

Ben Myers <bpm@sgi.com>

fs/xfs/xfs_attr_remote.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -52,10 +52,12 @@ xfs_attr3_rmt_blocks(
		struct xfs_mount *mp,
		int attrlen)
		{
		int buflen = XFS_ATTR3_RMT_BUF_SPACE(mp,
		mp->m_sb.sb_blocksize);
		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);
		}

		static bool
		xfs_attr3_rmt_verify(
		@@ -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,
		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);

		src = bp->b_addr;
		if (xfs_sb_version_hascrc(&mp->m_sb)) {

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