From 3380a03b00ada5d1f650ccbabd9a494a1fb65781 Mon Sep 17 00:00:00 2001
From: mav <mav@FreeBSD.org>
Date: Mon, 26 Aug 2013 20:39:02 +0000
Subject: MFprojects/camlock r254895: Add unmapped BIO support to GEOM ZERO if
 kern.geom.zero.clear is cleared.

---
 sys/geom/zero/g_zero.c | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

(limited to 'sys')

diff --git a/sys/geom/zero/g_zero.c b/sys/geom/zero/g_zero.c
index 1c2c54f..311db54 100644
--- a/sys/geom/zero/g_zero.c
+++ b/sys/geom/zero/g_zero.c
@@ -41,16 +41,37 @@ __FBSDID("$FreeBSD$");
 
 #define	G_ZERO_CLASS_NAME	"ZERO"
 
+static int	g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS);
+
 SYSCTL_DECL(_kern_geom);
 static SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW, 0,
     "GEOM_ZERO stuff");
 static int g_zero_clear = 1;
-SYSCTL_INT(_kern_geom_zero, OID_AUTO, clear, CTLFLAG_RW, &g_zero_clear, 0,
-    "Clear read data buffer");
+SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW,
+    &g_zero_clear, 0, g_zero_clear_sysctl, "I", "Clear read data buffer");
 static int g_zero_byte = 0;
 SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0,
     "Byte (octet) value to clear the buffers with");
 
+static struct g_provider *gpp;
+
+static int
+g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS)
+{
+	int error;
+
+	error = sysctl_handle_int(oidp, &g_zero_clear, 0, req);
+	if (error != 0 || req->newptr == NULL)
+		return (error);
+	if (gpp == NULL)
+		return (ENXIO);
+	if (g_zero_clear)
+		gpp->flags &= ~G_PF_ACCEPT_UNMAPPED;
+	else
+		gpp->flags |= G_PF_ACCEPT_UNMAPPED;
+	return (0);
+}
+
 static void
 g_zero_start(struct bio *bp)
 {
@@ -58,7 +79,7 @@ g_zero_start(struct bio *bp)
 
 	switch (bp->bio_cmd) {
 	case BIO_READ:
-		if (g_zero_clear)
+		if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0)
 			memset(bp->bio_data, g_zero_byte, bp->bio_length);
 		/* FALLTHROUGH */
 	case BIO_DELETE:
@@ -84,7 +105,9 @@ g_zero_init(struct g_class *mp)
 	gp = g_new_geomf(mp, "gzero");
 	gp->start = g_zero_start;
 	gp->access = g_std_access;
-	pp = g_new_providerf(gp, "%s", gp->name);
+	gpp = pp = g_new_providerf(gp, "%s", gp->name);
+	if (!g_zero_clear)
+		pp->flags |= G_PF_ACCEPT_UNMAPPED;
 	pp->mediasize = 1152921504606846976LLU;
 	pp->sectorsize = 512;
 	g_error_provider(pp, 0);
@@ -104,6 +127,7 @@ g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused,
 		return (0);
 	if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0)
 		return (EBUSY);
+	gpp = NULL;
 	g_wither_geom(gp, ENXIO);
 	return (0);
 }
-- 
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