- 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.

1 files changed, 96 insertions, 37 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");