diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 1d7c9a1f680ae146415e1dc753db7cb15f4d9e9b..24bd3591c8e0ec04507fc866157821c3ed50de29 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;
 	}
@@ -645,7 +645,7 @@ 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 d321f32ed9029538f35605c9be5a5e1ff02b18f6..24a0e73b08bb5b4b0b90c7d8db1855476f3706a5 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -1361,7 +1361,7 @@ 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])) {