On Sun, Aug 25, 2019 at 11:07:46PM -0600, Andreas Dilger wrote: > This may not always detect empty directory blocks properly, because > ext4_generic_delete_entry() will only merge deleted entries with the > previous entry. It at least appears possible that if entries are not > deleted in the proper order (e.g. in reverse of the order they are > listed in the directory) there may be multiple empty entries in a block, > and the above check will fail. I don't think that's a problem. We always merge with the previous entry, whether it's an empty/deleted entry or an in-use entry. So long as all implementations do this, it works just fine. If there is an ext2/3/4 implementation which deletes the entry by simply clearing the inode number *without* merging with the previous one, it's possible that we might get confused. But that's easily fixed, too. In ext4_generic_delete_entry(), we just need to add a check so that we check to see if the subsequent entry (if it exists) has a zero de->inode value. If so, then we absorb the current directory entry to include the deleted subsequent entry and repeat the check. - Ted
