xen/blkfront: cope with backend that fail empty BLKIF_OP_WRITE_BARRIER requests (dcb8baec) · Commits · 戴 / test

Some(?) Xen block backends fail BLKIF_OP_WRITE_BARRIER requests, which Linux uses as a cache flush operation. In that case, disable use of FLUSH. Signed-off-by:

Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Daniel Stodden <daniel.stodden@citrix.com>

drivers/block/xen-blkfront.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -656,6 +656,16 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
		printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
		info->gd->disk_name);
		error = -EOPNOTSUPP;
		}
		if (unlikely(bret->status == BLKIF_RSP_ERROR &&
		info->shadow[id].req.nr_segments == 0)) {
		printk(KERN_WARNING "blkfront: %s: empty write barrier op failed\n",
		info->gd->disk_name);
		error = -EOPNOTSUPP;
		}
		if (unlikely(error)) {
		if (error == -EOPNOTSUPP)
		error = 0;
		info->feature_flush = 0;
		xlvbd_flush(info);
		}

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