Add auto-fill-on-delete. When deleting an 'A'uto created partition

sysinstall will automatically expand the previous partition to take up
the freed up space.  So you can 'D'elete /home and /usr will get the
combined space, or you can 'D'elete /tmp and /var will get the combined space.

This gives the user, developer, or lay person a huge amount of flexibility
in constructing partitions from an 'A'uto base.  It takes only 3 or 4
keystrokes to achieve virtually any combination of having or not having
a /tmp and/or /home after doing an 'A'uto create.

Change 'A'uto creation of /var/tmp to 'A'uto creation /tmp, which should
be less controversial.

MFC after:	6 days

2 files changed, 38 insertions, 17 deletions

diff --git a/lib/libdisk/chunk.c b/lib/libdisk/chunk.c
index 83c247a..b2e9d3d 100644
--- a/lib/libdisk/chunk.c
+++ b/lib/libdisk/chunk.c
@@ -363,6 +363,7 @@ Delete_Chunk(struct disk *d, struct chunk *c)
 {
 	struct chunk *c1=0, *c2, *c3;
 	chunk_e type = c->type;
+	long offset = c->offset;
 
 	if(type == whole)
 		return 1;
@@ -398,9 +399,19 @@ Delete_Chunk(struct disk *d, struct chunk *c)
 	}
 	return 1;
     scan:
+	/*
+	 * Collapse multiple unused elements together, and attempt
+	 * to extend the previous chunk into the freed chunk.
+	 */
 	for(c2 = c1->part; c2; c2 = c2->next) {
-		if (c2->type != unused)
-			continue;
+		if (c2->type != unused) {
+			if (c2->offset + c2->size != offset ||
+			    (c2->flags & CHUNK_AUTO_SIZE) == 0 ||
+			    (c2->flags & CHUNK_NEWFS) == 0) {
+				continue;
+			}
+			/* else extend into free area */
+		}
 		if (!c2->next)
 			continue;
 		if (c2->next->type != unused)
diff --git a/lib/libdisk/libdisk.h b/lib/libdisk/libdisk.h
index 9457dfb..7281f8e 100644
--- a/lib/libdisk/libdisk.h
+++ b/lib/libdisk/libdisk.h
@@ -69,21 +69,6 @@ struct chunk {
 	chunk_e		type;
 	int		subtype;
 	u_long		flags;
-#		define CHUNK_BSD_COMPAT	2
-		/* this chunk is in the BSD-compatibility, and has a
-		 * short name too, ie wd0s4f -> wd0f
-		*/
-#		define CHUNK_ALIGN		8
-		/* This chunk should be aligned */
-#		define CHUNK_IS_ROOT		16
-		/* This 'part' is a rootfs, allocate 'a' */
-#		define CHUNK_ACTIVE		32
-		/* This is the active slice in the MBR */
-#		define CHUNK_FORCE_ALL		64
-		/* Force a dedicated disk for FreeBSD, bypassing
-		 * all BIOS geometry considerations
-		 */
-
 	void		(*private_free)(void*);
 	void		*(*private_clone)(void*);
 	void		*private_data;
@@ -94,6 +79,31 @@ struct chunk {
 	 */
 };
 
+/*
+ * flags:
+ *
+ * BSD_COMPAT	-	This chunk is in the BSD-compatibility, and has
+ *			a short name too, ie wd0s4f -> wd0f
+ * ALIGN	-	This chunk should be aligned
+ * IS_ROOT	-	This 'part' is a rootfs, allocate 'a'
+ * ACTIVE	-	This is the active slice in the MBR
+ * FORCE_ALL	-	Force a dedicated disk for FreeBSD, bypassing
+ *			all BIOS geometry considerations
+ * AUTO_SIZE	-	This chunk was auto-sized and can fill-out a
+ *			following chunk if the following chunk is deleted.
+ * NEWFS	-	newfs pending, used to enable auto-resizing on
+ *			delete (along with AUTO_SIZE).
+ */
+
+#define CHUNK_BSD_COMPAT	0x0002
+#define CHUNK_ALIGN		0x0008
+#define CHUNK_IS_ROOT		0x0010
+#define CHUNK_ACTIVE		0x0020
+#define CHUNK_FORCE_ALL		0x0040	
+#define CHUNK_AUTO_SIZE		0x0080
+#define CHUNK_NEWFS		0x0100
+
+
 extern const char *chunk_n[];
 
 const char *