[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: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index b0f0e58..8d9298c 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -997,7 +997,18 @@
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);
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 491d1f4..17ad5e4 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -304,14 +304,6 @@
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");
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 9bfb69e..db09e1e 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -949,6 +949,19 @@
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.
*/
if (XFS_TEST_ERROR((XFS_BUF_GETERROR(bp)), l->l_mp,