From d91e813c7b3dd2d89ef8ba12fb77abbe860a2e23 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Wed, 29 Dec 2010 12:11:07 +0000
Subject: [PATCH] Add reporting of GEOM::candelete BIO_GETATTR for md(4) and
 geom_disk(4). Non-zero value of attribute means that device supports
 BIO_DELETE.

Suggested and reviewed by:	pjd
Tested by:	pho
MFC after:	1 week
---
 sys/dev/md/md.c      | 5 +++--
 sys/geom/geom_disk.c | 6 +++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 314e289d5a3..ccd903910ff 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -717,11 +717,12 @@ md_kthread(void *arg)
 		}
 		mtx_unlock(&sc->queue_mtx);
 		if (bp->bio_cmd == BIO_GETATTR) {
-			if (sc->fwsectors && sc->fwheads &&
+			if ((sc->fwsectors && sc->fwheads &&
 			    (g_handleattr_int(bp, "GEOM::fwsectors",
 			    sc->fwsectors) ||
 			    g_handleattr_int(bp, "GEOM::fwheads",
-			    sc->fwheads)))
+			    sc->fwheads))) ||
+			    g_handleattr_int(bp, "GEOM::candelete", 1))
 				error = -1;
 			else
 				error = EOPNOTSUPP;
diff --git a/sys/geom/geom_disk.c b/sys/geom/geom_disk.c
index 25d2e3b92e6..4f918e87345 100644
--- a/sys/geom/geom_disk.c
+++ b/sys/geom/geom_disk.c
@@ -297,7 +297,11 @@ g_disk_start(struct bio *bp)
 		} while (bp2 != NULL);
 		break;
 	case BIO_GETATTR:
-		if (g_handleattr_int(bp, "GEOM::fwsectors", dp->d_fwsectors))
+		if (g_handleattr_int(bp, "GEOM::candelete",
+		    (dp->d_flags & DISKFLAG_CANDELETE) != 0))
+			break;
+		else if (g_handleattr_int(bp, "GEOM::fwsectors",
+		    dp->d_fwsectors))
 			break;
 		else if (g_handleattr_int(bp, "GEOM::fwheads", dp->d_fwheads))
 			break;