Make it possible to resize md(4) devices.

Reviewed by:	kib
Sponsored by:	FreeBSD Foundation

1 files changed, 71 insertions, 1 deletions

diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 8ff52a9..4d4c22c 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -1081,6 +1081,64 @@ mddestroy(struct md_s *sc, struct thread *td)
 }
 
 static int
+mdresize(struct md_s *sc, struct md_ioctl *mdio)
+{
+	int error, res;
+	vm_pindex_t oldpages, newpages;
+
+	switch (sc->type) {
+	case MD_VNODE:
+		break;
+	case MD_SWAP:
+		if (mdio->md_mediasize == 0 ||
+		    (mdio->md_mediasize % PAGE_SIZE) != 0)
+			return (EDOM);
+		oldpages = OFF_TO_IDX(round_page(sc->mediasize));
+		newpages = OFF_TO_IDX(round_page(mdio->md_mediasize));
+		if (newpages < oldpages) {
+			VM_OBJECT_LOCK(sc->object);
+			vm_object_page_remove(sc->object, newpages, 0, 0);
+			swap_pager_freespace(sc->object, newpages,
+			    oldpages - newpages);
+			swap_release_by_cred(IDX_TO_OFF(oldpages -
+			    newpages), sc->cred);
+			sc->object->charge = IDX_TO_OFF(newpages);
+			sc->object->size = newpages;
+			VM_OBJECT_UNLOCK(sc->object);
+		} else if (newpages > oldpages) {
+			res = swap_reserve_by_cred(IDX_TO_OFF(newpages -
+			    oldpages), sc->cred);
+			if (!res)
+				return (ENOMEM);
+			if ((mdio->md_options & MD_RESERVE) ||
+			    (sc->flags & MD_RESERVE)) {
+				error = swap_pager_reserve(sc->object,
+				    oldpages, newpages - oldpages);
+				if (error < 0) {
+					swap_release_by_cred(
+					    IDX_TO_OFF(newpages - oldpages),
+					    sc->cred);
+					return (EDOM);
+				}
+			}
+			VM_OBJECT_LOCK(sc->object);
+			sc->object->charge = IDX_TO_OFF(newpages);
+			sc->object->size = newpages;
+			VM_OBJECT_UNLOCK(sc->object);
+		}
+		break;
+	default:
+		return (EOPNOTSUPP);
+	}
+
+	sc->mediasize = mdio->md_mediasize;
+	g_topology_lock();
+	g_resize_provider(sc->pp, sc->mediasize);
+	g_topology_unlock();
+	return (0);
+}
+
+static int
 mdcreate_swap(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
 {
 	vm_ooffset_t npage;
@@ -1108,7 +1166,7 @@ mdcreate_swap(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
 	    VM_PROT_DEFAULT, 0, td->td_ucred);
 	if (sc->object == NULL)
 		return (ENOMEM);
-	sc->flags = mdio->md_options & MD_FORCE;
+	sc->flags = mdio->md_options & (MD_FORCE | MD_RESERVE);
 	if (mdio->md_options & MD_RESERVE) {
 		if (swap_pager_reserve(sc->object, 0, npage) < 0) {
 			error = EDOM;
@@ -1217,6 +1275,18 @@ xmdctlioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread
 		    !(mdio->md_options & MD_FORCE))
 			return (EBUSY);
 		return (mddestroy(sc, td));
+	case MDIOCRESIZE:
+		if ((mdio->md_options & ~(MD_FORCE | MD_RESERVE)) != 0)
+			return (EINVAL);
+
+		sc = mdfind(mdio->md_unit);
+		if (sc == NULL)
+			return (ENOENT);
+		if (mdio->md_mediasize < sc->mediasize &&
+		    !(sc->flags & MD_FORCE) &&
+		    !(mdio->md_options & MD_FORCE))
+			return (EBUSY);
+		return (mdresize(sc, mdio));
 	case MDIOCQUERY:
 		sc = mdfind(mdio->md_unit);
 		if (sc == NULL)