ext4_can_truncate
extern int ext4_can_truncate(struct inode *inode);
if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
if (pos + len > inode->i_size && ext4_can_truncate(inode))
if (extended && ext4_can_truncate(inode))
if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
if (!ext4_can_truncate(inode))