From e9702f17c6ac1f185cf58b45d7bba1b2df51a8b7 Mon Sep 17 00:00:00 2001 From: Zac Medico Date: Thu, 13 May 2010 16:39:22 -0700 Subject: Add a break_hardlinks parameter for tbz2 recompose methods, and enable it by default. Since bindbapi.aux_update() calls this method, this changes the default behavior for all modifications to binary package metadata. This makes it safe to use hardlinks to create cheap snapshots of the repository, which is useful for solving race conditions on binhosts as described here: http://code.google.com/p/chromium-os/issues/detail?id=3225. --- pym/portage/xpak.py | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/pym/portage/xpak.py b/pym/portage/xpak.py index 36aad39ff..7487d6728 100644 --- a/pym/portage/xpak.py +++ b/pym/portage/xpak.py @@ -25,6 +25,7 @@ import errno import shutil import sys +import portage from portage import os from portage import normalize_path from portage import _encodings @@ -295,17 +296,39 @@ class tbz2(object): def compose(self,datadir,cleanup=0): """Alias for recompose().""" return self.recompose(datadir,cleanup) - def recompose(self,datadir,cleanup=0): + + def recompose(self, datadir, cleanup=0, break_hardlinks=True): """Creates an xpak segment from the datadir provided, truncates the tbz2 to the end of regular data if an xpak segment already exists, and adds the new segment to the file with terminating info.""" xpdata = xpak(datadir) - self.recompose_mem(xpdata) + self.recompose_mem(xpdata, break_hardlinks=break_hardlinks) if cleanup: self.cleanup(datadir) - def recompose_mem(self, xpdata): + def recompose_mem(self, xpdata, break_hardlinks=True): + """ + Update the xpak segment. + @param xpdata: A new xpak segment to be written, like that returned + from the xpak_mem() function. + @param break_hardlinks: If hardlinks exist, create a copy in order + to break them. This makes it safe to use hardlinks to create + cheap snapshots of the repository, which is useful for solving + race conditions on binhosts as described here: + http://code.google.com/p/chromium-os/issues/detail?id=3225. + Default is True. + """ self.scan() # Don't care about condition... We'll rewrite the data anyway. + + if break_hardlinks and self.filestat.st_nlink > 1: + tmp_fname = "%s.%d" % (self.file, os.getpid()) + shutil.copyfile(self.file, tmp_fname) + try: + portage.util.apply_stat_permissions(self.file, self.filestat) + except portage.exception.OperationNotPermitted: + pass + os.rename(tmp_fname, self.file) + myfile = open(_unicode_encode(self.file, encoding=_encodings['fs'], errors='strict'), 'ab+') if not myfile: -- cgit v1.2.3-1-g7c22