Support a reverse use-case

[blackliner]

Hi, coming from here: https://unix.stackexchange.com/questions/782745/use-the-linux-filesystem-to-compress-files-on-the-fly

Would it be possible to add the capabilities to provide a folder with all files compressed? I.e. the other way round as it works today.

[shenek]

Hi,

I think that it might be possible. However after you do that all files in the mounted dir would seem like empty. You need to perform some fs operation to fix this (e.g. you may read first X bytes of each file).

This is caused because the mounted fs reads the size from xattr of the actual compressed file (user.real_size) and if the attribute is missing, the file is considered empty.

Note that the actual fix extracts entire file, recalculates uncompressed size and sets the attribute. So it is quite time consuming.