3 files changed, 43 insertions, 20 deletions

diff --git a/sys/geom/part/g_part.c b/sys/geom/part/g_part.c
index 9a345bb..7982945 100644
--- a/sys/geom/part/g_part.c
+++ b/sys/geom/part/g_part.c
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2002, 2005-2008 Marcel Moolenaar
+ * Copyright (c) 2002, 2005-2009 Marcel Moolenaar
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -110,23 +110,6 @@ static struct g_class g_part_class = {
 
 DECLARE_GEOM_CLASS(g_part_class, g_part);
 
-enum g_part_ctl {
-	G_PART_CTL_NONE,
-	G_PART_CTL_ADD,
-	G_PART_CTL_BOOTCODE,
-	G_PART_CTL_COMMIT,
-	G_PART_CTL_CREATE,
-	G_PART_CTL_DELETE,
-	G_PART_CTL_DESTROY,
-	G_PART_CTL_MODIFY,
-	G_PART_CTL_MOVE,
-	G_PART_CTL_RECOVER,
-	G_PART_CTL_RESIZE,
-	G_PART_CTL_SET,
-	G_PART_CTL_UNDO,
-	G_PART_CTL_UNSET
-};
-
 /*
  * Support functions.
  */
@@ -1349,7 +1332,7 @@ g_part_ctlreq(struct gctl_req *req, struct g_class *mp, const char *verb)
 
 	/* Obtain permissions if possible/necessary. */
 	close_on_error = 0;
-	table = NULL;	/* Suppress uninit. warning. */
+	table = NULL;
 	if (modifies && (gpp.gpp_parms & G_PART_PARM_GEOM)) {
 		table = gpp.gpp_geom->softc;
 		if (table != NULL && !table->gpt_opened) {
@@ -1365,7 +1348,16 @@ g_part_ctlreq(struct gctl_req *req, struct g_class *mp, const char *verb)
 		}
 	}
 
-	error = EDOOFUS;	/* Prevent bogus  uninit. warning. */
+	/* Allow the scheme to check or modify the parameters. */
+	if (table != NULL) {
+		error = G_PART_PRECHECK(table, ctlreq, &gpp);
+		if (error) {
+			gctl_error(req, "%d pre-check failed", error);
+			goto out;
+		}
+	} else
+		error = EDOOFUS;	/* Prevent bogus uninit. warning. */
+
 	switch (ctlreq) {
 	case G_PART_CTL_NONE:
 		panic("%s", __func__);
@@ -1421,6 +1413,7 @@ g_part_ctlreq(struct gctl_req *req, struct g_class *mp, const char *verb)
 		}
 	}
 
+ out:
 	if (error && close_on_error) {
 		g_access(LIST_FIRST(&gpp.gpp_geom->consumer), -1, -1, -1);
 		table->gpt_opened = 0;
diff --git a/sys/geom/part/g_part.h b/sys/geom/part/g_part.h
index cfc048d..353063b6 100644
--- a/sys/geom/part/g_part.h
+++ b/sys/geom/part/g_part.h
@@ -123,6 +123,23 @@ struct g_part_table {
 struct g_part_entry *g_part_new_entry(struct g_part_table *, int, quad_t,
     quad_t);
 
+enum g_part_ctl {
+	G_PART_CTL_NONE,
+	G_PART_CTL_ADD,
+	G_PART_CTL_BOOTCODE,
+	G_PART_CTL_COMMIT,
+	G_PART_CTL_CREATE,
+	G_PART_CTL_DELETE,
+	G_PART_CTL_DESTROY,
+	G_PART_CTL_MODIFY,
+	G_PART_CTL_MOVE,
+	G_PART_CTL_RECOVER,
+	G_PART_CTL_RESIZE,
+	G_PART_CTL_SET,
+	G_PART_CTL_UNDO,
+	G_PART_CTL_UNSET
+};
+
 /* G_PART ctlreq parameters. */
 #define	G_PART_PARM_ENTRIES	0x0001
 #define	G_PART_PARM_FLAGS	0x0002
diff --git a/sys/geom/part/g_part_if.m b/sys/geom/part/g_part_if.m
index 2a0a182..4993db1 100644
--- a/sys/geom/part/g_part_if.m
+++ b/sys/geom/part/g_part_if.m
@@ -95,6 +95,19 @@ METHOD const char * name {
 	size_t bufsz;
 };
 
+# precheck() - method to allow schemes to check the parameters given
+# to the mentioned ctl request. This only applies to the requests that
+# operate on a GEOM. In other words, it does not apply to the create
+# request.
+# It is allowed (intended actually) to change the parameters according
+# to the schemes needs before they are used. Returning an error will
+# terminate the request immediately.
+METHOD int precheck {
+	struct g_part_table *table;
+	enum g_part_ctl req;
+	struct g_part_parms *gpp;
+};
+
 # probe() - probe the provider attached to the given consumer for the
 # existence of the scheme implemented by the G_PART interface handler.
 METHOD int probe {