lkml.org 
[lkml]   [2014]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/3] xen/blkback: disable discard feature if requested by toolstack
Date
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: Olaf Hering <olaf@aepfle.de>
---
drivers/block/xen-blkback/xenbus.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index c2014a0..83125e2 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -467,10 +467,15 @@ 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",

\
 
 \ /
  Last update: 2014-02-10 18:41    [W:0.762 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site