Package: dpkg
Version: 1.15.6.1
Severity: important
Tags: patch
User: [email protected]
Usertags: origin-ubuntu ubuntu-patch lucid
The fsync/rename deferral in 1.15.6.1 doesn't actually seem to work
properly; strace doesn't show fsync at all for tarobjects. No wonder it
performed well! Admittedly I'm testing with my attempt to backport this
change to Ubuntu, but nevertheless I think I found a real bug:
if (ti->Type == NormalFile0 || ti->Type == NormalFile0) {
The second of those should be NormalFile1. Since modern tar files
generally use NormalFile1 rather than NormalFile0, the rename-deferral
path is never taken.
Performance testing will need to be repeated after fixing this bug. On
ext3, using Ubuntu's linux-headers-2.6.32-20_2.6.32-20.30_all.deb as a
test case, unpack times are within noise before and after the
fsync/rename deferral change with this bug fixed. I'm seeking testing
on ext4.
Patch attached.
Thanks,
--
Colin Watson [[email protected]]
>From 40a254a83dba8bf3b9030fb35b6d4e00eca46e01 Mon Sep 17 00:00:00 2001
From: Colin Watson <[email protected]>
Date: Wed, 14 Apr 2010 10:00:18 +0100
Subject: [PATCH] dpkg: fix rename deferral
Modern tar files typically use NormalFile1 rather than NormalFile0 for
file objects. A typo meant that the former never triggered rename
deferral.
---
debian/changelog | 5 +++++
src/archives.c | 2 +-
2 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/debian/changelog b/debian/changelog
index 3c14cc8..b385b80 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -27,6 +27,11 @@ dpkg (1.15.6.2) UNRELEASED; urgency=low
should now start using dpkg-buildflags instead. Closes: #560070
* For Ubuntu set default value of LDFLAGS to -Wl,-Bsymbolic-functions.
+ [ Colin Watson ]
+ * Modern tar files typically use NormalFile1 rather than NormalFile0 for
+ file objects. A typo meant that the former never triggered rename
+ deferral.
+
[ Updated dpkg translations ]
* German (Sven Joachim).
diff --git a/src/archives.c b/src/archives.c
index 79fef4e..0608137 100644
--- a/src/archives.c
+++ b/src/archives.c
@@ -779,7 +779,7 @@ int tarobject(struct TarInfo *ti) {
* in dpkg-new.
*/
- if (ti->Type == NormalFile0 || ti->Type == NormalFile0) {
+ if (ti->Type == NormalFile0 || ti->Type == NormalFile1) {
nifd->namenode->flags |= fnnf_deferred_rename;
debug(dbg_eachfiledetail, "tarobject done and installation deferred");
--
1.7.0
