[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

An easy way to reproduce the problem is with two recipes like the following:

first.bb:

SRC_URI = "svn://moderately.big.repo.com;module=trunk;protocol=https"
SRCREV = "1"


second.bb:

SRC_URI = "svn://moderately.big.repo.com;module=trunk;protocol=https"
SRCREV = "2"


Running 'bitbake first second' with empty download/sstate caches is then very
likely to trigger the issue.

Here's another guy that I think was having the same problem:
https://lists.yoctoproject.org/pipermail/yocto/2014-August/021383.html

Cheers,
Ulf