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Commit 0bfefc46 authored by David Chinner's avatar David Chinner Committed by Tim Shimmin
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[XFS] Barriers need to be dynamically checked and switched off 



If the underlying block device suddenly stops supporting barriers, we need
to handle the -EOPNOTSUPP error in a sane manner rather than shutting
down the filesystem. If we get this error, clear the barrier flag, reissue
the I/O, and tell the world bad things are occurring.

SGI-PV: 964544
SGI-Modid: xfs-linux-melb:xfs-kern:28568a

Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
parent c1561cf4

fs/xfs/linux-2.6/xfs_buf.c

+12 −1
Original line number Diff line number Diff line
@@ -997,7 +997,18 @@ xfs_buf_iodone_work( 
	xfs_buf_t		*bp =

		container_of(work, xfs_buf_t, b_iodone_work);



	if (bp->b_iodone)

	/*

	 * We can get an EOPNOTSUPP to ordered writes.  Here we clear the

	 * ordered flag and reissue them.  Because we can't tell the higher

	 * layers directly that they should not issue ordered I/O anymore, they

	 * need to check if the ordered flag was cleared during I/O completion.

	 */

	if ((bp->b_error == EOPNOTSUPP) &&

	    (bp->b_flags & (XBF_ORDERED|XBF_ASYNC)) == (XBF_ORDERED|XBF_ASYNC)) {

		XB_TRACE(bp, "ordered_retry", bp->b_iodone);

		bp->b_flags &= ~XBF_ORDERED;

		xfs_buf_iorequest(bp);

	} else if (bp->b_iodone)

		(*(bp->b_iodone))(bp);

	else if (bp->b_flags & XBF_ASYNC)

		xfs_buf_relse(bp);

fs/xfs/linux-2.6/xfs_super.c

+0 −8
Original line number Diff line number Diff line
@@ -304,14 +304,6 @@ xfs_mountfs_check_barriers(xfs_mount_t *mp) 
		return;

	}



	if (mp->m_ddev_targp->bt_bdev->bd_disk->queue->ordered ==

					QUEUE_ORDERED_NONE) {

		xfs_fs_cmn_err(CE_NOTE, mp,

		  "Disabling barriers, not supported by the underlying device");

		mp->m_flags &= ~XFS_MOUNT_BARRIER;

		return;

	}



	if (xfs_readonly_buftarg(mp->m_ddev_targp)) {

		xfs_fs_cmn_err(CE_NOTE, mp,

		  "Disabling barriers, underlying device is readonly");

fs/xfs/xfs_log.c

+13 −0
Original line number Diff line number Diff line
@@ -948,6 +948,19 @@ xlog_iodone(xfs_buf_t *bp) 
	 */

	l = iclog->ic_log;



	/*

	 * If the ordered flag has been removed by a lower

	 * layer, it means the underlyin device no longer supports

	 * barrier I/O. Warn loudly and turn off barriers.

	 */

	if ((l->l_mp->m_flags & XFS_MOUNT_BARRIER) && !XFS_BUF_ORDERED(bp)) {

		l->l_mp->m_flags &= ~XFS_MOUNT_BARRIER;

		xfs_fs_cmn_err(CE_WARN, l->l_mp,

				"xlog_iodone: Barriers are no longer supported"

				" by device. Disabling barriers\n");

		xfs_buftrace("XLOG_IODONE BARRIERS OFF", bp);

	}



	/*

	 * Race to shutdown the filesystem if we see an error.

	 */