Unable to delete files to trash in a bind-mounted filesystem

Question

I'm trying to set up shared home directory for two Linux installations and thus I'm using bind-mounts. My user is named dbz and his home directory is /home/dbz. I also have shared directory /home/shared where I store my shared files (this folder is also owned by user dbz).

I mount another directories from this shared directory into my home directory using binding:

mount -B /home/shared/work /home/dbz/work

This solution solves my needs and the only issue I have and don't know how to resolve is - when I'm trying to delete a file or directory from mounted directory I cannot delete it to trash, only permanent deletion is possible. For example:

• deleting file /home/shared/work/test.txt: OK, because deleting right from the directory where the file test.txt resides;
  
• deleting file /home/dbz/work/test.txt: CAN'T, because... by the way, because what? do bind-mounts have some restrictions on file deletion?

Finally an issue submitted to bugzilla.kernel.org

Answer 1

In order to make a trash directory you need to be able to make .Trash_<uid> at the mountpoint (at least on Ubuntu when deleting from nautilus, your distro might use another directory). If that directory cannot be made because the parent is not writable by dbz, you will not be able to backup.

It should not be necessary to have the parent directory writeable, it suffices to create the .Trash_<uid> as root and then chown it to dbz.

I find it somewhat easier to test things regarding trash file creation using the gvfs-trash utility, which actually gives an Error if the file cannot be trashed. Use something like:

touch /home/dbz/work/test.txt
strace gvfs-trash /home/dbz/work/test.txt  2>&1 | grep .Trash | grep mkdir

to see which directory it actually tries to make.

Answer 2

This is a linux kernel issue. It's not looking at the true super-block of the source and destination filesystems:

17926 rename("d1/foo", "d2/foo")        = -1 EXDEV (Invalid cross-device link)

Looks like the issue is in do_rename() (fs/namei.c):

    error = -EXDEV;
    if (oldnd.mnt != newnd.mnt)
            goto exit2;

*sigh*

Answer 3

Do you have a symbolic link for any of the parent directories of the Trash directory to another filesystem. I had ~/.local/share/Trash soft linked to a directory on a different filesystem, which led to this error. Of course, it still should work, but a work-around is to keep the Trash on the same filesystem.

Also, I found that the Ubuntu trash from package trash-cli works with that symlink, whereas gvfs-trash which is used by gnome applications does not work.

Answer 4

On nemo you can use this:
place this file at:
~/.local/share/nemo/actions/trash.nemo_action

[Nemo Action]
Active=true
Name=Move to Tra_sh(cli)
Comment=Trash even on mount binds
Exec=xterm -title "Trashing(cli)" -e trash -v %F
Selection=any
Extensions=any
EscapeSpaces=true

you can remove the xterm part and keep just the command.
you can change the shortcut but I suggest just pressing the context menu key over the files and just hit 's'.
I tested it with 1 file, many files, 1 folder and many folders selected, all worked!
I am quite sure this can work on nautilus too, I just dont remember where you should place an equivalent action.

PS.: related https://askubuntu.com/questions/1177100/how-to-fix-not-working-trash-on-bind-mounts-in-ubuntu-19-04-and-hide-them-in-n/1360837#1360837