diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index fa12fc9797998f6616c5fd554b2c8437babb432d..bf1f3d4d23f2765422a116ce3afcb85b66f83a72 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -187,7 +187,7 @@ int dbMount(struct inode *ipbmap)
 	}
 
 	bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
-	if (!bmp->db_numag) {
+	if (!bmp->db_numag || bmp->db_numag > MAXAG) {
 		err = -EINVAL;
 		goto err_release_metapage;
 	}
@@ -652,7 +652,7 @@ int dbNextAG(struct inode *ipbmap)
 	 * average free space.
 	 */
 	for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
-		if (agpref == bmp->db_numag)
+		if (agpref >= bmp->db_numag)
 			agpref = 0;
 
 		if (atomic_read(&bmp->db_active[agpref]))
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 36ed75682064852d1de288926ad641e4d81c0057..da3a1c27d3498bee9591f1f043c5b2e5e95c2de1 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -1362,7 +1362,7 @@ int diAlloc(struct inode *pip, bool dir, struct inode *ip)
 	/* get the ag number of this iag */
 	agno = BLKTOAG(JFS_IP(pip)->agstart, JFS_SBI(pip->i_sb));
 	dn_numag = JFS_SBI(pip->i_sb)->bmap->db_numag;
-	if (agno < 0 || agno > dn_numag)
+	if (agno < 0 || agno > dn_numag || agno >= MAXAG)
 		return -EIO;
 
 	if (atomic_read(&JFS_SBI(pip->i_sb)->bmap->db_active[agno])) {