From 822df19165c051fe091f1219f3f866b0423837a0 Mon Sep 17 00:00:00 2001
From: Panu Matilainen <pmatilai@redhat.com>
Date: Tue, 23 Jun 2020 11:17:24 +0300
Subject: [PATCH] Fix (work around) FA_TOUCH not scoping correctly over
 hardlinks

The existing FSM code doesn't correctly handle FA_TOUCH on hardlinked
file sets, which causes the hardlink set to break on at least some
upgrade scenarios when minimize_writes is enabled.

Only enable FA_TOUCH on non-hardlinked files to work around the issue
for now. While at it, rearrange the conditionals around min_writes to make
it a bit clearer. Testcase adopted from original reproducer by
Fabian Vogt, thanks!

Fixes: #1278
---
 lib/transaction.c             | 17 ++++++++++-------
 tests/Makefile.am             |  1 +
 tests/data/SPECS/hlbreak.spec | 22 ++++++++++++++++++++++
 tests/rpmverify.at            | 24 +++++++++++++++++++++++-
 4 files changed, 56 insertions(+), 8 deletions(-)
 create mode 100644 tests/data/SPECS/hlbreak.spec

diff --git a/lib/transaction.c b/lib/transaction.c
index 1156bb9f5b..9fea7b06bd 100644
--- a/lib/transaction.c
+++ b/lib/transaction.c
@@ -492,13 +492,6 @@ static void handleInstInstalledFile(const rpmts ts, rpmte p, rpmfiles fi, int fx
 	rpmfsSetAction(fs, fx, action);
     }
 
-    /* Skip already existing files - if 'minimize_writes' is set. */
-    if ((!isCfgFile) && (rpmfsGetAction(fs, fx) == FA_UNKNOWN)  && ts->min_writes) {
-	if (rpmfileContentsEqual(otherFi, ofx, fi, fx)) {
-	   rpmfsSetAction(fs, fx, FA_TOUCH);
-	}
-    }
-
     otherFileSize = rpmfilesFSize(otherFi, ofx);
 
     /* Only account for the last file of a hardlink set */
@@ -508,6 +501,16 @@ static void handleInstInstalledFile(const rpmts ts, rpmte p, rpmfiles fi, int fx
 
     /* Add one to make sure the size is not zero */
     rpmfilesSetFReplacedSize(fi, fx, otherFileSize + 1);
+
+    /* Just touch already existing files if minimize_writes is enabled */
+    if (ts->min_writes) {
+	if ((!isCfgFile) && (rpmfsGetAction(fs, fx) == FA_UNKNOWN)) {
+	    /* XXX fsm can't handle FA_TOUCH of hardlinked files */
+	    int nolinks = (nlink == 1 && rpmfilesFNlink(fi, fx) == 1);
+	    if (nolinks && rpmfileContentsEqual(otherFi, ofx, fi, fx))
+	       rpmfsSetAction(fs, fx, FA_TOUCH);
+	}
+    }
 }
 
 /**
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3c153dbc69..f7f63a91ae 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -59,6 +59,7 @@ EXTRA_DIST += data/SPECS/configtest.spec
 EXTRA_DIST += data/SPECS/filedep.spec
 EXTRA_DIST += data/SPECS/flangtest.spec
 EXTRA_DIST += data/SPECS/hlinktest.spec
+EXTRA_DIST += data/SPECS/hlbreak.spec
 EXTRA_DIST += data/SPECS/iftest.spec
 EXTRA_DIST += data/SPECS/ifmultiline.spec
 EXTRA_DIST += data/SPECS/eliftest.spec
diff --git a/tests/data/SPECS/hlbreak.spec b/tests/data/SPECS/hlbreak.spec
new file mode 100644
index 0000000000..d96d17261d
--- /dev/null
+++ b/tests/data/SPECS/hlbreak.spec
@@ -0,0 +1,22 @@
+Name: hlbreak
+Version: %{ver}
+Release: 0
+License: GPL
+Summary: Testing changing hardlink behavior
+BuildArch: noarch
+
+%description
+%{summary}
+
+%install
+mkdir -p %{buildroot}/opt
+echo "content" > %{buildroot}/opt/file2
+%if %{ver} == 1
+ln %{buildroot}/opt/file2 %{buildroot}/opt/file1
+%endif
+
+%files
+%if %{ver} == 1
+/opt/file1
+%endif
+/opt/file2
diff --git a/tests/rpmverify.at b/tests/rpmverify.at
index 43fa3e2337..02b0b8bea1 100644
--- a/tests/rpmverify.at
+++ b/tests/rpmverify.at
@@ -405,7 +405,29 @@ fox
 [])
 AT_CLEANUP
 
-AT_SETUP([minimize writes (links)])
+AT_SETUP([minimize writes (hardlinks)])
+AT_KEYWORDS([upgrade verify min_writes])
+RPMDB_INIT
+for v in "0" "1"; do
+    runroot rpmbuild --quiet -bb --define "ver ${v}" /data/SPECS/hlbreak.spec
+done
+AT_CHECK([
+RPMDB_INIT
+runroot rpm -U --define "_minimize_writes 1" /build/RPMS/noarch/hlbreak-0-0.noarch.rpm
+runroot rpm -Vav --nouser --nogroup
+runroot rpm -U --define "_minimize_writes 1" /build/RPMS/noarch/hlbreak-1-0.noarch.rpm
+runroot rpm -Vav --nouser --nogroup
+],
+[0],
+[.........    /opt/file2
+.........    /opt/file1
+.........    /opt/file2
+],
+)
+AT_CLEANUP
+
+
+AT_SETUP([minimize writes (symlinks)])
 AT_KEYWORDS([upgrade verify min_writes])
 RPMDB_INIT
 for v in "1.0" "2.0"; do