- Add genid field to the metadata which will allow to improve reliability a bit.

  After this change, when component is disconnected because of an I/O error,
  it will not be connected and synchronized automatically, it will be logged
  as broken and skipped. Autosynchronization can occur, when component is
  disconnected (on orphan event) and connected again - there were no I/O
  error, so there is no need to not connected the component, but when there were
  writes while it wasn't connected, it will be synchronized.
  This fix cases, when component is disconnected because of I/O error and can be
  connected again and again.
- Bump version number.
- Add version change history.
- Implement backward compatibility mechanism. After this change when metadata in
  old version is detected, it is automatically upgraded to the new (current)
  version.

3 files changed, 185 insertions, 57 deletions

diff --git a/sys/geom/mirror/g_mirror.c b/sys/geom/mirror/g_mirror.c
index fadf447..6e9f4f2 100644
--- a/sys/geom/mirror/g_mirror.c
+++ b/sys/geom/mirror/g_mirror.c
@@ -218,7 +218,6 @@ g_mirror_event_get(struct g_mirror_softc *sc)
 	return (ep);
 }
 
-
 static void
 g_mirror_event_remove(struct g_mirror_softc *sc, struct g_mirror_event *ep)
 {
@@ -445,6 +444,7 @@ g_mirror_init_disk(struct g_mirror_softc *sc, struct g_provider *pp,
 	disk->d_sync.ds_offset = md->md_sync_offset;
 	disk->d_sync.ds_offset_done = md->md_sync_offset;
 	disk->d_sync.ds_resync = -1;
+	disk->d_genid = md->md_genid;
 	disk->d_sync.ds_syncid = md->md_syncid;
 	if (errorp != NULL)
 		*errorp = 0;
@@ -544,7 +544,7 @@ g_mirror_orphan(struct g_consumer *cp)
 	disk = cp->private;
 	if (disk == NULL)
 		return;
-	disk->d_softc->sc_bump_syncid = G_MIRROR_BUMP_ON_FIRST_WRITE;
+	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID_OFW;
 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
 	    G_MIRROR_EVENT_DONTWAIT);
 }
@@ -559,7 +559,7 @@ g_mirror_spoiled(struct g_consumer *cp)
 	disk = cp->private;
 	if (disk == NULL)
 		return;
-	disk->d_softc->sc_bump_syncid = G_MIRROR_BUMP_IMMEDIATELY;
+	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID_IMM;
 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
 	    G_MIRROR_EVENT_DONTWAIT);
 }
@@ -635,7 +635,7 @@ g_mirror_write_metadata(struct g_mirror_disk *disk,
 	g_topology_lock();
 	free(sector, M_MIRROR);
 	if (error != 0) {
-		disk->d_softc->sc_bump_syncid = G_MIRROR_BUMP_IMMEDIATELY;
+		disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_GENID_IMM;
 		g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
 		    G_MIRROR_EVENT_DONTWAIT);
 	}
@@ -672,6 +672,7 @@ g_mirror_fill_metadata(struct g_mirror_softc *sc, struct g_mirror_disk *disk,
 	md->md_all = sc->sc_ndisks;
 	md->md_slice = sc->sc_slice;
 	md->md_balance = sc->sc_balance;
+	md->md_genid = sc->sc_genid;
 	md->md_mediasize = sc->sc_mediasize;
 	md->md_sectorsize = sc->sc_sectorsize;
 	md->md_mflags = (sc->sc_flags & G_MIRROR_DEVICE_FLAG_MASK);
@@ -741,6 +742,27 @@ g_mirror_bump_syncid(struct g_mirror_softc *sc)
 }
 
 static void
+g_mirror_bump_genid(struct g_mirror_softc *sc)
+{
+	struct g_mirror_disk *disk;
+
+	g_topology_assert();
+	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
+	    ("%s called with no active disks (device=%s).", __func__,
+	    sc->sc_name));
+
+	sc->sc_genid++;
+	G_MIRROR_DEBUG(1, "Device %s: genid bumped to %u.", sc->sc_name,
+	    sc->sc_genid);
+	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
+		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
+		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
+			g_mirror_update_metadata(disk);
+		}
+	}
+}
+
+static void
 g_mirror_idle(struct g_mirror_softc *sc)
 {
 	struct g_mirror_disk *disk;
@@ -880,7 +902,7 @@ g_mirror_regular_request(struct bio *bp)
 		G_MIRROR_LOGREQ(0, bp, "Request failed (error=%d).",
 		    bp->bio_error);
 		if (disk != NULL) {
-			sc->sc_bump_syncid = G_MIRROR_BUMP_IMMEDIATELY;
+			sc->sc_bump_id |= G_MIRROR_BUMP_GENID_IMM;
 			g_mirror_event_send(disk,
 			    G_MIRROR_DISK_STATE_DISCONNECTED,
 			    G_MIRROR_EVENT_DONTWAIT);
@@ -1062,7 +1084,7 @@ g_mirror_sync_request(struct bio *bp)
 			    "Synchronization request failed (error=%d).",
 			    bp->bio_error);
 			g_destroy_bio(bp);
-			sc->sc_bump_syncid = G_MIRROR_BUMP_IMMEDIATELY;
+			sc->sc_bump_id |= G_MIRROR_BUMP_GENID_IMM;
 			g_mirror_event_send(disk,
 			    G_MIRROR_DISK_STATE_DISCONNECTED,
 			    G_MIRROR_EVENT_DONTWAIT);
@@ -1381,8 +1403,8 @@ g_mirror_register_request(struct bio *bp)
 		/*
 		 * Bump syncid on first write.
 		 */
-		if (sc->sc_bump_syncid == G_MIRROR_BUMP_ON_FIRST_WRITE) {
-			sc->sc_bump_syncid = 0;
+		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID_OFW) != 0) {
+			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
 			g_topology_lock();
 			g_mirror_bump_syncid(sc);
 			g_topology_unlock();
@@ -1422,23 +1444,18 @@ static int
 g_mirror_try_destroy(struct g_mirror_softc *sc)
 {
 
+	g_topology_lock();
+	if (!g_mirror_can_destroy(sc)) {
+		g_topology_unlock();
+		return (0);
+	}
 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WAIT) != 0) {
-		g_topology_lock();
-		if (!g_mirror_can_destroy(sc)) {
-			g_topology_unlock();
-			return (0);
-		}
 		g_topology_unlock();
 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
 		    &sc->sc_worker);
 		wakeup(&sc->sc_worker);
 		sc->sc_worker = NULL;
 	} else {
-		g_topology_lock();
-		if (!g_mirror_can_destroy(sc)) {
-			g_topology_unlock();
-			return (0);
-		}
 		g_mirror_destroy_device(sc);
 		g_topology_unlock();
 		free(sc, M_MIRROR);
@@ -1861,8 +1878,8 @@ g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
 	switch (sc->sc_state) {
 	case G_MIRROR_DEVICE_STATE_STARTING:
 	    {
-		struct g_mirror_disk *pdisk;
-		u_int dirty, ndisks, syncid;
+		struct g_mirror_disk *pdisk, *tdisk;
+		u_int dirty, ndisks, genid, syncid;
 
 		KASSERT(sc->sc_provider == NULL,
 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
@@ -1911,7 +1928,28 @@ g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
 		}
 
 		/*
-		 * Find disk with the biggest syncid.
+		 * Find the biggest genid.
+		 */
+		genid = 0;
+		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
+			if (disk->d_genid > genid)
+				genid = disk->d_genid;
+		}
+		sc->sc_genid = genid;
+		/*
+		 * Remove all disks without the biggest genid.
+		 */
+		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
+			if (disk->d_genid < genid) {
+				G_MIRROR_DEBUG(0,
+				    "Component %s (device %s) broken, skipping.",
+				    g_mirror_get_diskname(disk), sc->sc_name);
+				g_mirror_destroy_disk(disk);
+			}
+		}
+
+		/*
+		 * Find the biggest syncid.
 		 */
 		syncid = 0;
 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
@@ -1999,7 +2037,7 @@ g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
 		sc->sc_syncid = syncid;
 		if (force) {
 			/* Remember to bump syncid on first write. */
-			sc->sc_bump_syncid = G_MIRROR_BUMP_ON_FIRST_WRITE;
+			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID_OFW;
 		}
 		state = G_MIRROR_DEVICE_STATE_RUNNING;
 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
@@ -2010,10 +2048,8 @@ g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
 			state = g_mirror_determine_state(disk);
 			g_mirror_event_send(disk, state,
 			    G_MIRROR_EVENT_DONTWAIT);
-			if (state == G_MIRROR_DISK_STATE_STALE) {
-				sc->sc_bump_syncid =
-				    G_MIRROR_BUMP_ON_FIRST_WRITE;
-			}
+			if (state == G_MIRROR_DISK_STATE_STALE)
+				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID_OFW;
 		}
 		wakeup(&g_mirror_class);
 		break;
@@ -2042,10 +2078,14 @@ g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
 		/*
 		 * Bump syncid here, if we need to do it immediately.
 		 */
-		if (sc->sc_bump_syncid == G_MIRROR_BUMP_IMMEDIATELY) {
-			sc->sc_bump_syncid = 0;
+		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID_IMM) != 0) {
+			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
 			g_mirror_bump_syncid(sc);
 		}
+		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID_IMM) != 0) {
+			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
+			g_mirror_bump_genid(sc);
+		}
 		break;
 	default:
 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
@@ -2233,8 +2273,8 @@ again:
 			 * Reset bumping syncid if disk disappeared in STARTING
 			 * state.
 			 */
-			if (sc->sc_bump_syncid == G_MIRROR_BUMP_ON_FIRST_WRITE)
-				sc->sc_bump_syncid = 0;
+			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID_OFW) != 0)
+				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
 #ifdef	INVARIANTS
 		} else {
 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
@@ -2296,6 +2336,8 @@ g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
 	g_topology_lock();
 	g_access(cp, -1, 0, 0);
 	if (error != 0) {
+		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
+		    cp->provider->name, error);
 		if (buf != NULL)
 			g_free(buf);
 		return (error);
@@ -2306,6 +2348,12 @@ g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
 	g_free(buf);
 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
 		return (EINVAL);
+	if (md->md_version > G_MIRROR_VERSION) {
+		G_MIRROR_DEBUG(0,
+		    "Kernel module is too old to handle metadata from %s.",
+		    cp->provider->name);
+		return (EINVAL);
+	}
 	if (error != 0) {
 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
 		    cp->provider->name);
@@ -2395,12 +2443,25 @@ g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
 	error = g_mirror_check_metadata(sc, pp, md);
 	if (error != 0)
 		return (error);
+	if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING &&
+	    md->md_genid < sc->sc_genid) {
+		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
+		    pp->name, sc->sc_name);
+		return (EINVAL);
+	}
 	disk = g_mirror_init_disk(sc, pp, md, &error);
 	if (disk == NULL)
 		return (error);
 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
 	    G_MIRROR_EVENT_WAIT);
-	return (error);
+	if (error != 0)
+		return (error);
+	if (md->md_version < G_MIRROR_VERSION) {
+		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
+		    pp->name, md->md_version, G_MIRROR_VERSION);
+		g_mirror_update_metadata(disk);
+	}
+	return (0);
 }
 
 static int
@@ -2481,7 +2542,7 @@ g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md)
 	sc->sc_sectorsize = md->md_sectorsize;
 	sc->sc_ndisks = md->md_all;
 	sc->sc_flags = md->md_mflags;
-	sc->sc_bump_syncid = 0;
+	sc->sc_bump_id = 0;
 	sc->sc_idle = 0;
 	bioq_init(&sc->sc_queue);
 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
@@ -2599,11 +2660,6 @@ g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
 		return (NULL);
 	gp = NULL;
 
-	if (md.md_version > G_MIRROR_VERSION) {
-		printf("geom_mirror.ko module is too old to handle %s.\n",
-		    pp->name);
-		return (NULL);
-	}
 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
 		return (NULL);
 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
@@ -2699,6 +2755,8 @@ g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
 		}
 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
 		    disk->d_sync.ds_syncid);
+		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
+		    disk->d_genid);
 		sbuf_printf(sb, "%s<Flags>", indent);
 		if (disk->d_flags == 0)
 			sbuf_printf(sb, "NONE");
@@ -2730,6 +2788,7 @@ g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
 	} else {
 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
+		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
 		sbuf_printf(sb, "%s<Flags>", indent);
 		if (sc->sc_flags == 0)
 			sbuf_printf(sb, "NONE");
diff --git a/sys/geom/mirror/g_mirror.h b/sys/geom/mirror/g_mirror.h
index a9cb27c..b80308d 100644
--- a/sys/geom/mirror/g_mirror.h
+++ b/sys/geom/mirror/g_mirror.h
@@ -35,7 +35,13 @@
 #define	G_MIRROR_CLASS_NAME	"MIRROR"
 
 #define	G_MIRROR_MAGIC		"GEOM::MIRROR"
-#define	G_MIRROR_VERSION	1
+/*
+ * Version history:
+ * 0 - Initial version number.
+ * 1 - Added 'prefer' balance algorithm.
+ * 2 - Added md_genid field to metadata.
+ */
+#define	G_MIRROR_VERSION	2
 
 #define	G_MIRROR_BALANCE_NONE		0
 #define	G_MIRROR_BALANCE_ROUND_ROBIN	1
@@ -125,6 +131,7 @@ struct g_mirror_disk {
 	struct bintime	 d_delay;	/* Disk delay. */
 	struct bintime	 d_last_used;	/* When disk was last used. */
 	uint64_t	 d_flags;	/* Additional flags. */
+	u_int		 d_genid;	/* Disk's generation ID. */
 	struct g_mirror_disk_sync d_sync;/* Sync information. */
 	LIST_ENTRY(g_mirror_disk) d_next;
 };
@@ -148,8 +155,15 @@ struct g_mirror_event {
 #define	G_MIRROR_DEVICE_STATE_STARTING		0
 #define	G_MIRROR_DEVICE_STATE_RUNNING		1
 
-#define	G_MIRROR_BUMP_ON_FIRST_WRITE		1
-#define	G_MIRROR_BUMP_IMMEDIATELY		2
+/* Bump syncid on first write. */
+#define	G_MIRROR_BUMP_SYNCID_OFW	0x1
+/* Bump syncid immediately. */
+#define	G_MIRROR_BUMP_SYNCID_IMM	0x2
+#define	G_MIRROR_BUMP_SYNCID		(G_MIRROR_BUMP_SYNCID_OFW | \
+					 G_MIRROR_BUMP_SYNCID_IMM)
+/* Bump genid immediately. */
+#define	G_MIRROR_BUMP_GENID_IMM		0x4
+#define	G_MIRROR_BUMP_GENID		(G_MIRROR_BUMP_GENID_IMM)
 struct g_mirror_softc {
 	u_int		sc_state;	/* Device state. */
 	uint32_t	sc_slice;	/* Slice size. */
@@ -171,8 +185,9 @@ struct g_mirror_softc {
 	u_int		sc_ndisks;	/* Number of disks. */
 	struct g_mirror_disk *sc_hint;
 
+	u_int		sc_genid;	/* Generation ID. */
 	u_int		sc_syncid;	/* Synchronization ID. */
-	int		sc_bump_syncid;
+	int		sc_bump_id;
 	struct g_mirror_device_sync sc_sync;
 	int		sc_idle;	/* DIRTY flags removed. */
 
@@ -201,6 +216,7 @@ struct g_mirror_metadata {
 	uint32_t	md_mid;		/* Mirror unique ID. */
 	uint32_t	md_did;		/* Disk unique ID. */
 	uint8_t		md_all;		/* Number of disks in mirror. */
+	uint32_t	md_genid;	/* Generation ID. */
 	uint32_t	md_syncid;	/* Synchronization ID. */
 	uint8_t		md_priority;	/* Disk priority. */
 	uint32_t	md_slice;	/* Slice size. */
@@ -225,28 +241,27 @@ mirror_metadata_encode(struct g_mirror_metadata *md, u_char *data)
 	le32enc(data + 36, md->md_mid);
 	le32enc(data + 40, md->md_did);
 	*(data + 44) = md->md_all;
-	le32enc(data + 45, md->md_syncid);
-	*(data + 49) = md->md_priority;
-	le32enc(data + 50, md->md_slice);
-	*(data + 54) = md->md_balance;
-	le64enc(data + 55, md->md_mediasize);
-	le32enc(data + 63, md->md_sectorsize);
-	le64enc(data + 67, md->md_sync_offset);
-	le64enc(data + 75, md->md_mflags);
-	le64enc(data + 83, md->md_dflags);
-	bcopy(md->md_provider, data + 91, 16);
+	le32enc(data + 45, md->md_genid);
+	le32enc(data + 49, md->md_syncid);
+	*(data + 53) = md->md_priority;
+	le32enc(data + 54, md->md_slice);
+	*(data + 58) = md->md_balance;
+	le64enc(data + 59, md->md_mediasize);
+	le32enc(data + 67, md->md_sectorsize);
+	le64enc(data + 71, md->md_sync_offset);
+	le64enc(data + 79, md->md_mflags);
+	le64enc(data + 87, md->md_dflags);
+	bcopy(md->md_provider, data + 95, 16);
 	MD5Init(&ctx);
-	MD5Update(&ctx, data, 107);
+	MD5Update(&ctx, data, 111);
 	MD5Final(md->md_hash, &ctx);
-	bcopy(md->md_hash, data + 107, 16);
+	bcopy(md->md_hash, data + 111, 16);
 }
 static __inline int
-mirror_metadata_decode(const u_char *data, struct g_mirror_metadata *md)
+mirror_metadata_decode_v0v1(const u_char *data, struct g_mirror_metadata *md)
 {
 	MD5_CTX ctx;
 
-	bcopy(data, md->md_magic, 16);
-	md->md_version = le32dec(data + 16);
 	bcopy(data + 20, md->md_name, 16);
 	md->md_mid = le32dec(data + 36);
 	md->md_did = le32dec(data + 40);
@@ -267,8 +282,61 @@ mirror_metadata_decode(const u_char *data, struct g_mirror_metadata *md)
 	MD5Final(md->md_hash, &ctx);
 	if (bcmp(md->md_hash, data + 107, 16) != 0)
 		return (EINVAL);
+
+	/* New fields. */
+	md->md_genid = 0;
+
 	return (0);
 }
+static __inline int
+mirror_metadata_decode_v2(const u_char *data, struct g_mirror_metadata *md)
+{
+	MD5_CTX ctx;
+
+	bcopy(data + 20, md->md_name, 16);
+	md->md_mid = le32dec(data + 36);
+	md->md_did = le32dec(data + 40);
+	md->md_all = *(data + 44);
+	md->md_genid = le32dec(data + 45);
+	md->md_syncid = le32dec(data + 49);
+	md->md_priority = *(data + 53);
+	md->md_slice = le32dec(data + 54);
+	md->md_balance = *(data + 58);
+	md->md_mediasize = le64dec(data + 59);
+	md->md_sectorsize = le32dec(data + 67);
+	md->md_sync_offset = le64dec(data + 71);
+	md->md_mflags = le64dec(data + 79);
+	md->md_dflags = le64dec(data + 87);
+	bcopy(data + 95, md->md_provider, 16);
+	bcopy(data + 111, md->md_hash, 16);
+	MD5Init(&ctx);
+	MD5Update(&ctx, data, 111);
+	MD5Final(md->md_hash, &ctx);
+	if (bcmp(md->md_hash, data + 111, 16) != 0)
+		return (EINVAL);
+	return (0);
+}
+static __inline int
+mirror_metadata_decode(const u_char *data, struct g_mirror_metadata *md)
+{
+	int error;
+
+	bcopy(data, md->md_magic, 16);
+	md->md_version = le32dec(data + 16);
+	switch (md->md_version) {
+	case 0:
+	case 1:
+		error = mirror_metadata_decode_v0v1(data, md);
+		break;
+	case 2:
+		error = mirror_metadata_decode_v2(data, md);
+		break;
+	default:
+		error = EINVAL;
+		break;
+	}
+	return (error);
+}
 
 static __inline const char *
 balance_name(u_int balance)
@@ -320,6 +388,7 @@ mirror_metadata_dump(const struct g_mirror_metadata *md)
 	printf("       mid: %u\n", (u_int)md->md_mid);
 	printf("       did: %u\n", (u_int)md->md_did);
 	printf("       all: %u\n", (u_int)md->md_all);
+	printf("     genid: %u\n", (u_int)md->md_genid);
 	printf("    syncid: %u\n", (u_int)md->md_syncid);
 	printf("  priority: %u\n", (u_int)md->md_priority);
 	printf("     slice: %u\n", (u_int)md->md_slice);
diff --git a/sys/geom/mirror/g_mirror_ctl.c b/sys/geom/mirror/g_mirror_ctl.c
index 2afa1ac..65c52bd 100644
--- a/sys/geom/mirror/g_mirror_ctl.c
+++ b/sys/geom/mirror/g_mirror_ctl.c
@@ -527,7 +527,7 @@ g_mirror_ctl_deactivate(struct gctl_req *req, struct g_class *mp)
 		disk->d_flags |= G_MIRROR_DISK_FLAG_INACTIVE;
 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
 		g_mirror_update_metadata(disk);
-		sc->sc_bump_syncid = G_MIRROR_BUMP_ON_FIRST_WRITE;
+		sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID_OFW;
 		g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
 		    G_MIRROR_EVENT_WAIT);
 	}