From e426311befe429ad39b47927cd12153b7aa99542 Mon Sep 17 00:00:00 2001 From: "Kyle J. McKay" Date: Thu, 26 Feb 2015 05:49:34 -0800 Subject: [PATCH] Git::SVN::*: avoid premature FileHandle closure Since b19138b (git-svn: Make it incrementally faster by minimizing temp files, v1.6.0), git-svn has been using the Git.pm temp_acquire and temp_release mechanism to avoid unnecessary temp file churn and provide a speed boost. However, that change introduced a call to temp_acquire inside the Git::SVN::Fetcher::close_file function for an 'svn_hash' temp file. Because an SVN::Pool is active at the time this function is called, if the Git::temp_acquire function ends up actually creating a new FileHandle for the temp file (which it will the first time it's called with the name 'svn_hash') that FileHandle will end up in the SVN::Pool and should that pool have SVN::Pool::clear called on it that FileHandle will be closed out from under Git::temp_acquire. Since the only call site to Git::temp_acquire with the name 'svn_hash' is inside the close_file function, if an 'svn_hash' temp file is ever created its FileHandle is guaranteed to be created in the active SVN::Pool. This has not been a problem in the past because the SVN::Pool was not being cleared. However, since dfa72fdb (git-svn: reload RA every log-window-size, v2.2.0) the pool has been getting cleared periodically at which point the FileHandle for the 'svn_hash' temp file gets closed. Any subsequent calls to Git::temp_acquire for 'svn_hash', however, succeed without creating/opening a new temporary file since it still has the now invalid FileHandle in its cache. Callers that then attempt to use that FileHandle fail with an error. We avoid this problem by making sure the 'svn_hash' temp file is created in the same place the 'svn_delta_...' and 'git_blob_...' temp files are (and then temp_release'd) so that it can be safely used inside the close_file function without having its FileHandle end up in an SVN::Pool that gets cleared. Additionally the Git.pm cat_blob function creates a bidirectional pipe FileHandle using the IPC::Open2::open2 function. If that handle is created too late, it also gets caught up in the SVN::Pool and incorrectly closed by the SVN::Pool::clear call. But this only seems to happen with more recent versions of Perl and svn. To avoid this problem we add an explicit call to _open_cat_blob_if_needed before the first call to SVN::Pool->new_default to make sure the open2 handle does not end up in the SVN::Pool. Signed-off-by: Kyle J. McKay Signed-off-by: Eric Wong Signed-off-by: Junio C Hamano --- perl/Git/SVN/Fetcher.pm | 8 ++++++++ perl/Git/SVN/Ra.pm | 3 +++ 2 files changed, 11 insertions(+) diff --git a/perl/Git/SVN/Fetcher.pm b/perl/Git/SVN/Fetcher.pm index 10edb27732..613055a3f5 100644 --- a/perl/Git/SVN/Fetcher.pm +++ b/perl/Git/SVN/Fetcher.pm @@ -322,6 +322,14 @@ sub apply_textdelta { # (but $base does not,) so dup() it for reading in close_file open my $dup, '<&', $fh or croak $!; my $base = $::_repository->temp_acquire("git_blob_${$}_$suffix"); + # close_file may call temp_acquire on 'svn_hash', but because of the + # call chain, if the temp_acquire call from close_file ends up being the + # call that first creates the 'svn_hash' temp file, then the FileHandle + # that's created as a result will end up in an SVN::Pool that we clear + # in SVN::Ra::gs_fetch_loop_common. Avoid that by making sure the + # 'svn_hash' FileHandle is already created before close_file is called. + my $tmp_fh = $::_repository->temp_acquire('svn_hash'); + $::_repository->temp_release($tmp_fh, 1); if ($fb->{blob}) { my ($base_is_link, $size); diff --git a/perl/Git/SVN/Ra.pm b/perl/Git/SVN/Ra.pm index 622535e217..32e2f19ea4 100644 --- a/perl/Git/SVN/Ra.pm +++ b/perl/Git/SVN/Ra.pm @@ -391,6 +391,9 @@ sub longest_common_path { sub gs_fetch_loop_common { my ($self, $base, $head, $gsv, $globs) = @_; return if ($base > $head); + # Make sure the cat_blob open2 FileHandle is created before calling + # SVN::Pool::new_default so that it does not incorrectly end up in the pool. + $::_repository->_open_cat_blob_if_needed; my $gpool = SVN::Pool->new_default; my $ra_url = $self->url; my $reload_ra = sub { -- 2.11.4.GIT