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Commit c926b701 authored by Olaf Hering's avatar Olaf Hering Committed by Konrad Rzeszutek Wilk
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xen/blkback: disable discard feature if requested by toolstack 



Newer toolstacks may provide a boolean property "discard-enable" in the
backend node. Its purpose is to disable discard for file backed storage
to avoid fragmentation. Recognize this setting also for physical
storage.  If that property exists and is false, do not advertise
"feature-discard" to the frontend.

Signed-off-by: default avatarOlaf Hering <olaf@aepfle.de>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 1c8cad6c

drivers/block/xen-blkback/xenbus.c

+6 −1
Original line number Diff line number Diff line
@@ -481,10 +481,15 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info 
	struct xenbus_device *dev = be->dev;

	struct xen_blkif *blkif = be->blkif;

	int err;

	int state = 0;

	int state = 0, discard_enable;

	struct block_device *bdev = be->blkif->vbd.bdev;

	struct request_queue *q = bdev_get_queue(bdev);



	err = xenbus_scanf(XBT_NIL, dev->nodename, "discard-enable", "%d",

			   &discard_enable);

	if (err == 1 && !discard_enable)

		return;



	if (blk_queue_discard(q)) {

		err = xenbus_printf(xbt, dev->nodename,

			"discard-granularity", "%u",