From: Zac Medico <zmedico@gentoo.org>
Date: Wed, 8 Dec 2010 19:23:48 +0000 (-0800)
Subject: Preserve existing hardlinks during merge.
X-Git-Tag: v2.2.0_alpha8~5
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=f8cb556ac6680b8e3d8c3090c3cb7abae04cb242;p=portage.git

Preserve existing hardlinks during merge.

The previous code created hardlinks rather aggressively, which was
helpful as a workaround for lack of hardlinks in tarballs created
by quickpkg due to bug #185305. Since bug #338509, quickpkg tarballs
preserve hardlinks, so there's no need for aggressive hardlink
creation. Therefore, simply preserve existing hardlinks during merge,
by comparison of st_dev and st_ino from the source files.
---

diff --git a/pym/portage/dbapi/vartree.py b/pym/portage/dbapi/vartree.py
index d3704b598..d269e93ea 100644
--- a/pym/portage/dbapi/vartree.py
+++ b/pym/portage/dbapi/vartree.py
@@ -3762,25 +3762,14 @@ class dblink(object):
 				# whether config protection or not, we merge the new file the
 				# same way.  Unless moveme=0 (blocking directory)
 				if moveme:
-					# Do not hardlink files unless they are in the same
-					# directory, since otherwise tar may not be able to
-					# extract a tarball of the resulting hardlinks due to
-					# 'Invalid cross-device link' errors (depends on layout of
-					# mount points). Also, don't hardlink zero-byte files since
-					# it doesn't save any space, and don't hardlink
-					# CONFIG_PROTECTed files since config files shouldn't be
-					# hardlinked to eachother (for example, shadow installs
-					# several identical config files inside /etc/pam.d/).
-					parent_dir = os.path.dirname(myrealdest)
-					hardlink_key = (parent_dir, mymd5, mystat.st_size,
-						mystat.st_mode, mystat.st_uid, mystat.st_gid)
-
-					hardlink_candidates = None
-					if not protected and mystat.st_size != 0:
-						hardlink_candidates = self._md5_merge_map.get(hardlink_key)
-						if hardlink_candidates is None:
-							hardlink_candidates = []
-							self._md5_merge_map[hardlink_key] = hardlink_candidates
+					# Create hardlinks only for source files that already exist
+					# as hardlinks (having identical st_dev and st_ino).
+					hardlink_key = (mystat.st_dev, mystat.st_ino)
+
+					hardlink_candidates = self._md5_merge_map.get(hardlink_key)
+					if hardlink_candidates is None:
+						hardlink_candidates = []
+						self._md5_merge_map[hardlink_key] = hardlink_candidates
 
 					mymtime = movefile(mysrc, mydest, newmtime=thismtime,
 						sstat=mystat, mysettings=self.settings,