diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 2ec35889ad24..5088da13e8f1 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -1360,6 +1360,9 @@ int diAlloc(struct inode *pip, bool dir, struct inode *ip)
 	if (agno < 0 || agno > dn_numag)
 		return -EIO;
 
+	if (unlikely(dn_numag > MAXAG))
+		return -EIO;
+
 	if (atomic_read(&JFS_SBI(pip->i_sb)->bmap->db_active[agno])) {
 		/*
 		 * There is an open file actively growing.  We want to