From: Michael Tremer <michael.tremer@ipfire.org>
Date: Thu, 27 Jun 2013 18:34:46 +0000 (+0000)
Subject: daemon: Check if build root is read-write mounted.
X-Git-Tag: 0.9.26~10^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d251d8e78546049e37205b9c9a9a320e2b2e4036;p=pakfire.git

daemon: Check if build root is read-write mounted.

If there has been a connection error, iSCSI LUNs
remount themselves as read-only to prevent data-loss.

To stop starting new build jobs, we now have a check
and even try to remount the build root if we can.
---

diff --git a/python/pakfire/builder.py b/python/pakfire/builder.py
index 68c9fd4b4..cf2608c19 100644
--- a/python/pakfire/builder.py
+++ b/python/pakfire/builder.py
@@ -168,6 +168,11 @@ class BuildEnviron(object):
 	def start(self):
 		assert not self.pakfire.initialized, "Pakfire has already been initialized"
 
+		# Check if we can write our build directory.
+		build_mp = system.get_mountpoint(self.pakfire.path)
+		if build_mp and build_mp.is_readonly():
+			raise RuntimeError, "Build directory is read-only: %s" % self.pakfire.path
+
 		# Unshare namepsace.
 		# If this fails because the kernel has no support for CLONE_NEWIPC or CLONE_NEWUTS,
 		# we try to fall back to just set CLONE_NEWNS.
diff --git a/python/pakfire/daemon.py b/python/pakfire/daemon.py
index 67fdd69c2..8b4f8c81d 100644
--- a/python/pakfire/daemon.py
+++ b/python/pakfire/daemon.py
@@ -386,6 +386,11 @@ class PakfireWorker(multiprocessing.Process):
 		self.transport = transport.PakfireHubTransport(self.config)
 
 		while self.__running:
+			# Check if the build root is file.
+			if not self.check_buildroot():
+				time.sleep(60)
+				continue
+
 			# Try to get a new build job.
 			job = self.get_new_build_job()
 			if not job:
@@ -428,9 +433,27 @@ class PakfireWorker(multiprocessing.Process):
 		"""
 		self.shutdown()
 
+	def check_buildroot(self):
+		"""
+			Checks if the buildroot is fine.
+		"""
+		mp = system.get_mountpoint(BUILD_ROOT)
+
+		# Check if the mountpoint is read-only.
+		if mp.is_readonly():
+			log.warning("Build directory is read-only: %s" % BUILD_ROOT)
+
+			# Trying to remount.
+			try:
+				mp.remount("rw")
+			except:
+				log.warning("Remounting (rw) %s has failed" % BUILD_ROOT)
+				return False
+			else:
+				log.warning("Successfully remounted as rw: %s" % BUILD_ROOT)
+
 	def get_new_build_job(self, timeout=600):
 		log.debug("Requesting new job...")
-
 		try:
 			job = self.transport.get_json("/builders/jobs/queue",
 				data={ "timeout" : timeout, }, timeout=timeout)
diff --git a/python/pakfire/system.py b/python/pakfire/system.py
index a917461fd..2bba80208 100644
--- a/python/pakfire/system.py
+++ b/python/pakfire/system.py
@@ -24,8 +24,10 @@ from __future__ import division
 import multiprocessing
 import os
 import socket
+import tempfile
 
 import distro
+import shell
 
 from i18n import _
 
@@ -346,6 +348,9 @@ class Mountpoint(object):
 		# Save the amount of data that is used or freed.
 		self.disk_usage = 0
 
+	def __repr__(self):
+		return "<%s %s>" % (self.__class__.__name__, self.fullpath)
+
 	def __cmp__(self, other):
 		return cmp(self.fullpath, other.fullpath)
 
@@ -405,6 +410,45 @@ class Mountpoint(object):
 
 		self.disk_usage -= file.size
 
+	def is_readonly(self):
+		"""
+			Returns True if the mountpoint is mounted read-only.
+			Otherwise False.
+		"""
+		# Using the statvfs output does not really work, so we use
+		# a very naive approach here, were we just try to create a
+		# new file. If that works, it's writable.
+
+		try:
+			handle, path = tempfile.mkstemp(prefix="ro-test-", dir=self.fullpath)
+		except OSError, e:
+			# Read-only file system.
+			if e.errno == 30:
+				return True
+
+			# Raise all other exceptions.
+			raise
+		else:
+			# Close the file and remove it.
+			os.close(handle)
+			os.unlink(path)
+
+		return False
+
+	def remount(self, rorw=None):
+		options = "remount"
+		if rorw in ("ro", "rw"):
+			options = "%s,%s" % (options, rorw)
+
+		try:
+			shellenv = shell.ShellExecuteEnvironment(
+				["mount", "-o", options, self.fullpath],
+				shell=False,
+			)
+			shellenv.execute()
+		except ShellEnvironmentError, e:
+			raise OSError
+
 
 if __name__ == "__main__":
 	print "Hostname", system.hostname