From: Daniel Stodden <daniel.stodden@citrix.com>
Date: Fri, 15 Oct 2010 01:17:31 +0000 (-0700)
Subject: CP-1840: Count ENOSPC redirects.
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=3982b28d1c5d35f4226b2e113d2072000f2d2f92;p=people%2Fdstodden%2Fblktap.git

CP-1840: Count ENOSPC redirects.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
---

diff --git a/drivers/tapdisk-vbd.c b/drivers/tapdisk-vbd.c
index d20a07b..ae52f0c 100644
--- a/drivers/tapdisk-vbd.c
+++ b/drivers/tapdisk-vbd.c
@@ -1305,6 +1305,16 @@ tapdisk_vbd_complete_vbd_request(td_vbd_t *vbd, td_vbd_request_t *vreq)
 	}
 }
 
+static void
+FIXME_maybe_count_enospc_redirect(td_vbd_t *vbd, td_request_t treq)
+{
+	int write = treq.op == TD_OP_WRITE;
+	if (write &&
+	    treq.image == tapdisk_vbd_first_image(vbd) &&
+	    vbd->FIXME_enospc_redirect_count_enabled)
+		vbd->FIXME_enospc_redirect_count += treq.secs;
+}
+
 static void
 __tapdisk_vbd_complete_td_request(td_vbd_t *vbd, td_vbd_request_t *vreq,
 				  td_request_t treq, int res)
@@ -1322,6 +1332,8 @@ __tapdisk_vbd_complete_td_request(td_vbd_t *vbd, td_vbd_request_t *vreq,
 		if (err)
 			td_sector_count_add(&image->stats.fail,
 					    treq.secs, write);
+
+		FIXME_maybe_count_enospc_redirect(vbd, treq);
 	}
 
 	if (err) {
@@ -1439,6 +1451,7 @@ tapdisk_vbd_complete_td_request(td_request_t treq, int res)
 		} else if (vbd->secondary_mode == TD_VBD_SECONDARY_STANDBY) {
 			DPRINTF("ENOSPC: failing over to secondary image\n");
 			list_add(&vbd->secondary->next, leaf->next.prev);
+			vbd->FIXME_enospc_redirect_count_enabled = 1;
 		}
 		if (vbd->secondary_mode != TD_VBD_SECONDARY_DISABLED) {
 			vbd->secondary = NULL;
@@ -1875,5 +1888,9 @@ tapdisk_vbd_stats(td_vbd_t *vbd, td_stats_t *st)
 		tapdisk_image_stats(image, st);
 	tapdisk_stats_leave(st, ']');
 
+	tapdisk_stats_field(st,
+			    "FIXME_enospc_redirect_count",
+			    "llu", vbd->FIXME_enospc_redirect_count);
+
 	tapdisk_stats_leave(st, '}');
 }
diff --git a/drivers/tapdisk-vbd.h b/drivers/tapdisk-vbd.h
index d69804a..00bd966 100644
--- a/drivers/tapdisk-vbd.h
+++ b/drivers/tapdisk-vbd.h
@@ -103,6 +103,9 @@ struct td_vbd_handle {
 	td_image_t                 *secondary;
 	uint8_t                     secondary_mode;
 
+	int                         FIXME_enospc_redirect_count_enabled;
+	uint64_t                    FIXME_enospc_redirect_count;
+
 	/* when we encounter ENOSPC on the primary leaf image in mirror mode, 
 	 * we need to remove it from the VBD chain so that writes start going 
 	 * on the secondary leaf. However, we cannot free the image at that