BTRFS_NAME_LEN
if (dentry->d_name.len > BTRFS_NAME_LEN)
buf->f_namelen = BTRFS_NAME_LEN;
if (unlikely(name_len > BTRFS_NAME_LEN)) {
key->type, name_len, BTRFS_NAME_LEN);
if (unlikely(namelen == 0 || namelen > BTRFS_NAME_LEN)) {
namelen, BTRFS_NAME_LEN);
max_name_len = BTRFS_NAME_LEN;
char namebuf[MAX(BTRFS_NAME_LEN, XATTR_NAME_MAX)];