[bitbake-devel] [PATCH] bitbake: fetch2/svn: Fix SVN repository concurrent update race

[Ulf.Magnusson at bmw.de]

The ${DL_DIR}/svn directory is used by BitBake to keep checked-out SVN
repositories from which tarballs are generated. These repositories were
protected from concurrent update with a lock on the tarballs. However,
the tarballs are specific to the SRCREV and module checked out (many
tarballs can come from the same repository), meaning a repository could
be modified concurrently if two recipes checked out two different
SRCREVs or modules from it in parallel.

This caused errors like the following:

ERROR: Fetcher failure: Fetch command failed with exit code 1, output:
svn: E155004: Run 'svn cleanup' to remove locks (type 'svn help cleanup' for details)
svn: E155004: Working copy '/home/foo/downloads/svn/repo/trunk' locked.
svn: E155004: '/home/foo/downloads/svn/repo/trunk' is already locked.

Fix it by adding a per-repository lock that's independent of the module
and SRCREV.
---
 bitbake/lib/bb/fetch2/svn.py | 69 +++++++++++++++++++++++++-------------------
 1 file changed, 39 insertions(+), 30 deletions(-)

diff --git a/bitbake/lib/bb/fetch2/svn.py b/bitbake/lib/bb/fetch2/svn.py
index 8a29193..f83b740 100644
--- a/bitbake/lib/bb/fetch2/svn.py
+++ b/bitbake/lib/bb/fetch2/svn.py
@@ -63,6 +63,9 @@ class Svn(FetchMethod):
         relpath = self._strip_leading_slashes(ud.path)
         ud.pkgdir = os.path.join(data.expand('${SVNDIR}', d), ud.host, relpath)
         ud.moddir = os.path.join(ud.pkgdir, ud.module)
+        # Protects the repository from concurrent updates, e.g. from two
+        # recipes fetching different revisions at the same time
+        ud.svnlock = os.path.join(ud.pkgdir, "svn.lock")
 
         ud.setup_revisons(d)
 
@@ -123,38 +126,44 @@ class Svn(FetchMethod):
 
         logger.debug(2, "Fetch: checking for module directory '" + ud.moddir + "'")
 
-        if os.access(os.path.join(ud.moddir, '.svn'), os.R_OK):
-            svnupdatecmd = self._buildsvncommand(ud, d, "update")
-            logger.info("Update " + ud.url)
-            # update sources there
-            os.chdir(ud.moddir)
-            # We need to attempt to run svn upgrade first in case its an older working format
-            try:
-                runfetchcmd(ud.basecmd + " upgrade", d)
-            except FetchError:
-                pass
-            logger.debug(1, "Running %s", svnupdatecmd)
-            bb.fetch2.check_network_access(d, svnupdatecmd, ud.url)
-            runfetchcmd(svnupdatecmd, d)
-        else:
-            svnfetchcmd = self._buildsvncommand(ud, d, "fetch")
-            logger.info("Fetch " + ud.url)
-            # check out sources there
-            bb.utils.mkdirhier(ud.pkgdir)
-            os.chdir(ud.pkgdir)
-            logger.debug(1, "Running %s", svnfetchcmd)
-            bb.fetch2.check_network_access(d, svnfetchcmd, ud.url)
-            runfetchcmd(svnfetchcmd, d)
+        lf = bb.utils.lockfile(ud.svnlock)
+
+        try:
+            if os.access(os.path.join(ud.moddir, '.svn'), os.R_OK):
+                svnupdatecmd = self._buildsvncommand(ud, d, "update")
+                logger.info("Update " + ud.url)
+                # update sources there
+                os.chdir(ud.moddir)
+                # We need to attempt to run svn upgrade first in case its an older working format
+                try:
+                    runfetchcmd(ud.basecmd + " upgrade", d)
+                except FetchError:
+                    pass
+                logger.debug(1, "Running %s", svnupdatecmd)
+                bb.fetch2.check_network_access(d, svnupdatecmd, ud.url)
+                runfetchcmd(svnupdatecmd, d)
+            else:
+                svnfetchcmd = self._buildsvncommand(ud, d, "fetch")
+                logger.info("Fetch " + ud.url)
+                # check out sources there
+                bb.utils.mkdirhier(ud.pkgdir)
+                os.chdir(ud.pkgdir)
+                logger.debug(1, "Running %s", svnfetchcmd)
+                bb.fetch2.check_network_access(d, svnfetchcmd, ud.url)
+                runfetchcmd(svnfetchcmd, d)
+
+            scmdata = ud.parm.get("scmdata", "")
+            if scmdata == "keep":
+                tar_flags = ""
+            else:
+                tar_flags = "--exclude '.svn'"
 
-        scmdata = ud.parm.get("scmdata", "")
-        if scmdata == "keep":
-            tar_flags = ""
-        else:
-            tar_flags = "--exclude '.svn'"
+            os.chdir(ud.pkgdir)
+            # tar them up to a defined filename
+            runfetchcmd("tar %s -czf %s %s" % (tar_flags, ud.localpath, ud.path_spec), d, cleanup = [ud.localpath])
 
-        os.chdir(ud.pkgdir)
-        # tar them up to a defined filename
-        runfetchcmd("tar %s -czf %s %s" % (tar_flags, ud.localpath, ud.path_spec), d, cleanup = [ud.localpath])
+        finally:
+            bb.utils.unlockfile(lf)
 
     def clean(self, ud, d):
         """ Clean SVN specific files and dirs """
-- 
2.7.4