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From: "mark at klomp dot org" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug debuginfod/28240] debuginfod client cache falsely sticky for
 root user
Date: Sun, 24 Apr 2022 18:48:30 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D28240

--- Comment #3 from Mark Wielaard <mark at klomp dot org> ---
We got rid of the zero-permission 000 files with:

commit 8b568fdea8e1baea3d68cc38dec587e4c9219276
Author: Aaron Merey <amerey@redhat.com>
Date:   Fri Apr 8 19:37:11 2022 -0400

    PR29022: 000-permissions files cause problems for backups

    000-permission files currently used for negative caching can cause
    permission problems for some backup software and disk usage checkers.
    Fix this by using empty files for negative caching instead.

    Also use each empty file's mtime to determine the time since
    last download attempt instead of the cache_miss_s file's mtime.

    https://sourceware.org/bugzilla/show_bug.cgi?id=3D29022

    Tested-by: Milian Wolff <mail@milianw.de>
    Signed-off-by: Aaron Merey <amerey@redhat.com>

And I think that also got rid of this race issue.

Any other client that races past us now will either create a new empty file
with=20=20=20
open (target_cache_path, O_CREAT|O_EXCL, DEFFILEMODE) or puts in a new
non-empty file using rename (target_cache_tmppath, target_cache_path). Both=
 of
which are atomic.

So I think this is resolved now. But would like someone else to double chec=
k.
These races are tricky.

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