diff --git a/gfs2/fsck/fsck.h b/gfs2/fsck/fsck.h
index d3f7635..877448c 100644
--- a/gfs2/fsck/fsck.h
+++ b/gfs2/fsck/fsck.h
@@ -4,6 +4,8 @@
 #include "libgfs2.h"
 #include "osi_tree.h"
 
+#define FSCK_MAX_FORMAT (1801)
+
 #define FSCK_HASH_SHIFT         (13)
 #define FSCK_HASH_SIZE          (1 << FSCK_HASH_SHIFT)
 #define FSCK_HASH_MASK          (FSCK_HASH_SIZE - 1)
diff --git a/gfs2/fsck/initialize.c b/gfs2/fsck/initialize.c
index ebe62b9..d1c620a 100644
--- a/gfs2/fsck/initialize.c
+++ b/gfs2/fsck/initialize.c
@@ -1334,12 +1334,12 @@ static int fill_super_block(struct gfs2_sbd *sdp)
 	if (sizeof(struct gfs2_sb) > sdp->sd_sb.sb_bsize){
 		log_crit( _("GFS superblock is larger than the blocksize!\n"));
 		log_debug("sizeof(struct gfs2_sb) > sdp->sd_sb.sb_bsize\n");
-		return -1;
+		return FSCK_ERROR;
 	}
 
 	if (compute_constants(sdp)) {
 		log_crit("%s\n", _("Failed to compute file system constants"));
-		exit(FSCK_ERROR);
+		return FSCK_ERROR;
 	}
 	ret = read_sb(sdp);
 	if (ret < 0) {
@@ -1348,10 +1348,15 @@ static int fill_super_block(struct gfs2_sbd *sdp)
 		/* Now that we've tried to repair it, re-read it. */
 		ret = read_sb(sdp);
 		if (ret < 0)
-			return -1;
+			return FSCK_ERROR;
 	}
 	if (sdp->gfs1)
 		sbd1 = (struct gfs_sb *)&sdp->sd_sb;
+	else if (sdp->sd_sb.sb_fs_format > FSCK_MAX_FORMAT) {
+		log_crit(_("Unsupported gfs2 format found: %"PRIu32"\n"), sdp->sd_sb.sb_fs_format);
+		log_crit(_("A newer fsck.gfs2 is required to check this file system.\n"));
+		return FSCK_USAGE;
+	}
 	return 0;
 }
 
@@ -1556,6 +1561,7 @@ int initialize(struct gfs2_sbd *sdp, int force_check, int preen,
 	       int *all_clean)
 {
 	int clean_journals = 0, open_flag;
+	int err;
 
 	*all_clean = 0;
 
@@ -1601,8 +1607,9 @@ int initialize(struct gfs2_sbd *sdp, int force_check, int preen,
 	}
 
 	/* read in sb from disk */
-	if (fill_super_block(sdp))
-		return FSCK_ERROR;
+	err = fill_super_block(sdp);
+	if (err != FSCK_OK)
+		return err;
 
 	/* Change lock protocol to be fsck_* instead of lock_* */
 	if (!opts.no && preen_is_safe(sdp, preen, force_check)) {
diff --git a/gfs2/libgfs2/super.c b/gfs2/libgfs2/super.c
index 6e7d8c2..7592564 100644
--- a/gfs2/libgfs2/super.c
+++ b/gfs2/libgfs2/super.c
@@ -29,11 +29,18 @@ int check_sb(struct gfs2_sb *sb)
 		errno = EIO;
 		return -1;
 	}
+	/* Check for gfs1 */
 	if (sb->sb_fs_format == GFS_FORMAT_FS &&
 	    sb->sb_header.mh_format == GFS_FORMAT_SB &&
 	    sb->sb_multihost_format == GFS_FORMAT_MULTI) {
 		return 1;
 	}
+	/* It's gfs2. Check format number is in a sensible range. */
+	if (sb->sb_fs_format < GFS2_FORMAT_FS ||
+	    sb->sb_fs_format > 1899) {
+		errno = EINVAL;
+		return -1;
+	}
 	return 2;
 }
 
diff --git a/tests/fsck.at b/tests/fsck.at
index 39a04d0..97a00a9 100644
--- a/tests/fsck.at
+++ b/tests/fsck.at
@@ -54,3 +54,16 @@ AT_CHECK([gfs2_edit -p journal0 field di_header.mh_magic 0 $GFS_TGT], 0, [ignore
 AT_CHECK([fsck.gfs2 -y $GFS_TGT], 1, [ignore], [ignore])
 AT_CHECK([fsck.gfs2 -n $GFS_TGT], 0, [ignore], [ignore])
 AT_CLEANUP
+
+AT_SETUP([gfs2 format versions])
+AT_KEYWORDS(fsck.gfs2 fsck)
+GFS_TGT_REGEN
+AT_CHECK([mkfs.gfs2 -O -p lock_nolock ${GFS_TGT}], 0, [ignore], [ignore])
+AT_CHECK([echo "set sb { sb_fs_format: 1802 }" | gfs2l ${GFS_TGT}], 0, [ignore], [ignore])
+# Unsupported format, FSCK_USAGE == 16
+AT_CHECK([fsck.gfs2 -y $GFS_TGT], 16, [ignore], [ignore])
+# Format out of range
+AT_CHECK([echo "set sb { sb_fs_format: 4242 }" | gfs2l ${GFS_TGT}], 0, [ignore], [ignore])
+AT_CHECK([fsck.gfs2 -y $GFS_TGT], 1, [ignore], [ignore])
+AT_CHECK([fsck.gfs2 -n $GFS_TGT], 0, [ignore], [ignore])
+AT_CLEANUP