From: Jeff King <peff@peff.net>
To: Horst Schirmeier <horst@schirmeier.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 0/6] deadlock regression in v2.11.0 with failed mkdtemp
Date: Tue, 7 Mar 2017 08:50:13 -0500 [thread overview]
Message-ID: <20170307135012.fdk6jhhl4zspdk2v@sigill.intra.peff.net> (raw)
In-Reply-To: <20170307133437.qee2jtynbiwf6uzr@sigill.intra.peff.net>
On Tue, Mar 07, 2017 at 08:34:37AM -0500, Jeff King wrote:
> Yuck. In the original, the error was generated by the child index-pack,
> and we relayed it over the sideband. But we don't even get as far as
> running index-pack in the newer version; we fail trying to make the
> tmpdir. The error ends up in the "unpack" protocol field, but the client
> side does a bad job of showing that. With the rest of the patches, it
> looks like:
>
> $ git push ~/tmp/foo.git HEAD
> Counting objects: 210973, done.
> Delta compression using up to 8 threads.
> Compressing objects: 100% (52799/52799), done.
> error: remote unpack failed: unable to create temporary object directory
> error: failed to push some refs to '/home/peff/tmp/foo.git'
There are two other options here I should mention.
One is that when pack-objects dies, we suppress the ref-status table
entirely. Which is fair, because it doesn't have anything interesting to
say. But for a case like this where the other side stops reading our
pack early but still produces status reports, we could actually read
them all and have a status table like:
$ git push ~/tmp/foo.git HEAD
Counting objects: 209843, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (52186/52186), done.
error: remote unpack failed: unable to create temporary object directory
To /home/peff/tmp/foo.git
! [remote rejected] HEAD -> jk/push-index-pack-deadlock (unpacker error)
error: failed to push some refs to '/home/peff/tmp/foo.git'
We'd have to take some care to make sure we handle the case when the
remote _doesn't_ manage to give us the status (e.g., when there's a
complete hangup). I don't know if it's worth the effort. There's no new
information there.
The second thing is that I think the design of the "unpack <reason>"
report is a bit dated. These days everybody supports the sideband
protocol, so it would probably make more sense to just issue the
"<reason>" report via the sideband (at which point it gets a nice
"remote: " prefix).
We could do something like this:
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index f2c6953a3..6204d3d00 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1670,6 +1670,8 @@ static const char *unpack(int err_fd, struct shallow_info *si)
if (!tmp_objdir) {
if (err_fd > 0)
close(err_fd);
+ rp_error("unable to create temporary object directory: %s",
+ strerror(errno));
return "unable to create temporary object directory";
}
child.env = tmp_objdir_env(tmp_objdir);
and drop the "try to show the unpack failure" parts of my series, and
you'd end up with:
$ git push ~/tmp/foo.git HEAD
Counting objects: 209843, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (52186/52186), done.
remote: error: unable to create temporary object directory: Permission denied
error: failed to push some refs to '/home/peff/tmp/foo.git'
but in cases where pack-objects _doesn't_ fail, existing git versions
do show the "unpack" error. So you'd see it twice.
I don't know if it's worth trying to hack around.
-Peff
next prev parent reply other threads:[~2017-03-07 14:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-07 11:03 regression: git push in non-shared repo stalls (v2.11.0+) Horst Schirmeier
2017-03-07 11:14 ` Horst Schirmeier
2017-03-07 13:34 ` [PATCH 0/6] deadlock regression in v2.11.0 with failed mkdtemp Jeff King
2017-03-07 13:35 ` [PATCH 1/6] receive-pack: fix deadlock when we cannot create tmpdir Jeff King
2017-03-07 13:35 ` [PATCH 2/6] send-pack: extract parsing of "unpack" response Jeff King
2017-03-07 13:36 ` [PATCH 3/6] send-pack: use skip_prefix for parsing unpack status Jeff King
2017-03-07 13:37 ` [PATCH 4/6] send-pack: improve unpack-status error messages Jeff King
2017-03-07 22:56 ` Junio C Hamano
2017-03-08 5:45 ` Jeff King
2017-03-08 17:19 ` Junio C Hamano
2017-03-07 13:38 ` [PATCH 5/6] send-pack: read "unpack" status even on pack-objects failure Jeff King
2017-03-07 13:39 ` [PATCH 6/6] send-pack: report signal death of pack-objects Jeff King
2017-03-07 13:50 ` Jeff King [this message]
2017-03-08 17:58 ` [PATCH 0/6] deadlock regression in v2.11.0 with failed mkdtemp Horst Schirmeier
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