Trashing doesn't work across different devices (linux)

[kampffrosch94]

I am trashing a file in a zfs dataset different from the one my home directory is mounted in and get the following error:
Message: Invalid cross-device link (os error 18)
It seems to be a limitation of using rename.

[Byron]

Thanks for letting me know. The assumption is that the trash folder is located on the same filesystem and currently there are no precautions for that.
Please also note that I didn't try to reproduce the issue, but also believe that move won't work across filesystems (when using the naive system call at least).

A decent way of fixing this would probably be to better determine the location of the trash directory, which should never be outside of the file system of the files to be trashed. I'd be interested to hear how the standard OS 'delete file' functionality handles this with details on where puts the trash directory, and how it's organized.

[ArturKovacs]

This might be of some help:
https://specifications.freedesktop.org/trash-spec/trashspec-latest.html

But looking at an actual implementation would possibly be more useful.

[ja0nz]

I haven't read the source code but this is how trash-cli seems to solve this one:

Deletion / trash-put

• if deleted file resides withing SAME mount point as /home/user -> move to ~/.local/share/Trash/files (accompanied with a ~/.local/share/Trash/info metadata record)
• if deleted file resides in a DIFFERENT mount point file tree -> move to mntpoint/.Trash-$UID/files again with metadata record. So eventually deleted files stay in their origin partition/volume.

Listing / trash-list

Crawl all mount points for .Trash-$UID directories plus ~/.local/share/Trash and listing the files x.trashinfo metadata which contains the relavant information as absolute path:

[Trash Info]
Path=/home/user/mntpoint/to/a/subvolume
DeletionDate=2022-11-08T19:56:19

[Byron]

Thanks a lot for the hints, they will certainly help with a fix.