From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH container] backup: warn that tar does not honor exclusion pattern with a trailing slash
Date: Fri, 31 May 2024 12:07:52 +0200 [thread overview]
Message-ID: <20240531100753.40964-1-f.ebner@proxmox.com> (raw)
As reported in the community forum [0], for tar, an exclusion pattern
with a trailing slash will not match a folder with that name. For
rsync and proxmox-backup-client however, such a pattern will exclude
a directory with that name, but not a file.
rsync is used for 'suspend' mode backup and tar is used for all
non-PBS backups to create the archive. So currently, in the presence
of an exclusion pattern with a trailing slash, there is inconsistency
between different backup modes (because for 'suspend' mode, rsync will
already do the exclusion too) as well as between PBS and non-PBS
backups.
There doesn't seem to be a straight-forward way to align the behavior
for tar with command-line options exactly. The trailing slash can't be
removed from the pattern, because that would also match files.
Matching with
> some/pattern/*
> some/pattern/.*
rather than
> some/pattern/
gets pretty close, which was suggested by Dominik. Just the empty
directory is still included.
In any case, modifying current behavior would be a breaking change, so
actually aligning the exclusion (more closely) is better done in the
next major release.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
One could argue such a change is a bug-fix and so does not need to
wait until the next major release. I opted for the safer variant for
now, but happy to go with the aligning already if that is preferred.
src/PVE/VZDump/LXC.pm | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/src/PVE/VZDump/LXC.pm b/src/PVE/VZDump/LXC.pm
index 8c28a5e..914ede2 100644
--- a/src/PVE/VZDump/LXC.pm
+++ b/src/PVE/VZDump/LXC.pm
@@ -442,7 +442,16 @@ sub archive {
} else {
push @findexcl_anchored, $pattern;
}
- }
+
+ # NOTE rsync and proxmox-backup-client will match directories, but not files when there
+ # is a trailing slash, tar won't match either. For suspend mode, rsync already did the
+ # exclusion, so no need to warn.
+ # TODO PVE 9 - consider matching "$pattern*" and "$pattern.*" in this case, which will
+ # only include the empty directory to more closely align the behavior between different
+ # modes. Don't forget to update the docs!
+ $self->log("warn", "tar does not match exclusion with a trailing slash '$pattern'")
+ if $pattern =~ m|/$| && $task->{mode} ne 'suspend';
+ }
push @$tar, '--no-anchored';
push @$tar, '--exclude=lost+found' if $userns_cmd;
--
2.39.2
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next reply other threads:[~2024-05-31 10:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-31 10:07 Fiona Ebner [this message]
2024-05-31 10:07 ` [pve-devel] [PATCH docs] " Fiona Ebner
2024-09-10 14:35 ` [pve-devel] applied: [PATCH container] " Thomas Lamprecht
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