bug#41607: Deleted store items are not actually deleted

[Ludovic Courtès]

Howdy!

Christopher Marusich <cmmarusich@gmail.com> skribis:

> Here is a patch.  Turns out it's was just a one line change!  If nobody
> has any further feedback on it, I'll go ahead and merge it to the master
> branch in the next couple days.

Yay!

> From 505481a6a22819a42320f693988c3f8e13ded080 Mon Sep 17 00:00:00 2001
> From: Chris Marusich <cmmarusich@gmail.com>
> Date: Thu, 4 Jun 2020 23:26:19 -0700
> Subject: [PATCH] daemon: Handle EXDEV when moving to trash directory.
>
> Fixes <https://bugs.gnu.org/41607>.
> Reported by Stephen Scheck <singularsyntax@gmail.com>.
>
> * nix/libstore/gc.cc (LocalStore::deletePathRecursive): When we try to
> move a dead directory into the trashDir using rename(2) but it returns
> an EXDEV error, just delete the directory instead.  This can happen in a
> Docker container when the directory is not on the "top layer".
> ---
>  nix/libstore/gc.cc | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/nix/libstore/gc.cc b/nix/libstore/gc.cc
> index 8bc4e01eb0..845fe278c7 100644
> --- a/nix/libstore/gc.cc
> +++ b/nix/libstore/gc.cc
> @@ -455,7 +455,10 @@ void LocalStore::deletePathRecursive(GCState & state, 
> const Path & path)
>                  throw SysError(format("unable to rename `%1%' to `%2%'") % 
> path % tmp);
>              state.bytesInvalidated += size;
>          } catch (SysError & e) {
> -            if (e.errNo == ENOSPC) {
> +            // In a Docker container, rename(2) returns EXDEV when the source
> +            // and destination are not both on the "top layer".  See:
> +            // https://bugs.gnu.org/41607
> +            if (e.errNo == ENOSPC || e.errNo == EXDEV) {
>                  printMsg(lvlInfo, format("note: can't create move `%1%': 
> %2%") % path % e.msg());
>                  deleteGarbage(state, path);
>              }

For consistency with (most) of the code, I’d suggest a /* */ comment.

Otherwise LGTM, thank you!

Ludo’.