From 4bc1fd6e3941be74027594efad3d2358a93702df Mon Sep 17 00:00:00 2001 From: Ævar Arnfjörð Bjarmason Date: Thu, 9 Sep 2021 19:25:00 -0400 Subject: pack-objects: rename .idx files into place after .bitmap files MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In preceding commits the race of renaming .idx files in place before .rev files and other auxiliary files was fixed in pack-write.c's finish_tmp_packfile(), builtin/repack.c's "struct exts", and builtin/index-pack.c's final(). As noted in the change to pack-write.c we left in place the issue of writing *.bitmap files after the *.idx, let's fix that issue. See 7cc8f971085 (pack-objects: implement bitmap writing, 2013-12-21) for commentary at the time when *.bitmap was implemented about how those files are written out, nothing in that commit contradicts what's being done here. Note that this commit and preceding ones only close any race condition with *.idx files being written before their auxiliary files if we're optimistic about our lack of fsync()-ing in this are not tripping us over. See the thread at [1] for a rabbit hole of various discussions about filesystem races in the face of doing and not doing fsync() (and if doing fsync(), not doing it properly). We may want to fsync the containing directory once after renaming the *.idx file into place, but that is outside the scope of this series. 1. https://lore.kernel.org/git/8735qgkvv1.fsf@evledraar.gmail.com/ Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- builtin/pack-objects.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'builtin/pack-objects.c') diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c index 0a46584922..7a3632828c 100644 --- a/builtin/pack-objects.c +++ b/builtin/pack-objects.c @@ -1250,7 +1250,6 @@ static void write_pack_file(void) stage_tmp_packfiles(&tmpname, pack_tmp_name, written_list, nr_written, &pack_idx_opts, hash, &idx_tmp_name); - rename_tmp_packfile_idx(&tmpname, &idx_tmp_name); if (write_bitmap_index) { size_t tmpname_len = tmpname.len; @@ -1267,6 +1266,8 @@ static void write_pack_file(void) strbuf_setlen(&tmpname, tmpname_len); } + rename_tmp_packfile_idx(&tmpname, &idx_tmp_name); + free(idx_tmp_name); strbuf_release(&tmpname); free(pack_tmp_name); -- cgit v1.2.3