mounts: introduce new plugin for mountpoints tuning

- currently supports only barrier handling

tuned/plugins/base.py

@@ -189,9 +189,9 @@ class Plugin(object):
 		return value == "true" or value == "1"
 
 	def _config_bool(self, value, true_value="1", false_value="0"):
-		if value == True or value == "1" or value.lower() == "true":
+		if value == True or value == "1" or str(value).lower() == "true":
 			return true_value
-		elif value == False or value == "0" or value.lower() == "false":
+		elif value == False or value == "0" or str(value).lower() == "false":
 			return false_value
 		else:
 			return None

tuned/plugins/plugin_mounts.py

@@ -0,0 +1,143 @@
+import base
+from decorators import *
+from subprocess import Popen,PIPE
+import tuned.logs
+import tuned.utils.commands
+import glob
+
+log = tuned.logs.get()
+
+class MountsPlugin(base.Plugin):
+	"""
+	Plugin for tuning options of mount-points.
+	"""
+
+	_mountpoint_topology = None
+
+	def _post_init(self):
+		self._dynamic_tuning = False
+
+	@classmethod
+	def _generate_mountpoint_topology(cls):
+		mountpoint_topology = {}
+		current_disk = None
+
+		stdout, stderr = Popen(["/usr/bin/lsblk", "-rno", "TYPE,RM,KNAME,FSTYPE,MOUNTPOINT"], stdout=PIPE, stderr=PIPE).communicate()
+		for columns in map(lambda line: line.split(), stdout.splitlines()):
+			device_type, device_removable, device_name = columns[:3]
+			filesystem = columns[3] if len(columns) > 3 else None
+			mountpoint = columns[4] if len(columns) > 4 else None
+
+			if device_type == "disk":
+				current_disk = device_name
+				continue
+
+			# skip removable, skip nonpartitions
+			if device_removable == "1" or device_type not in ["part", "lvm"]:
+				continue
+
+			if mountpoint is None or mountpoint == "[SWAP]":
+				continue
+
+			mountpoint_topology.setdefault(mountpoint, {"disks": set(), "device_name": device_name, "filesystem": filesystem})
+			mountpoint_topology[mountpoint]["disks"].add(current_disk)
+
+		cls._mountpoint_topology = mountpoint_topology
+
+	@classmethod
+	def tunable_devices(cls):
+		if cls._mountpoint_topology is None:
+			cls._generate_mountpoint_topology()
+		return set(cls._mountpoint_topology.keys())
+
+	@classmethod
+	def _get_default_options(cls):
+		return {
+			"disable_barriers": None,
+		}
+
+	def _get_device_cache_type(self, device):
+		source_filenames = glob.glob("/sys/block/%s/device/scsi_disk/*/cache_type" % device)
+		for source_filename in source_filenames:
+			return tuned.utils.commands.read_file(source_filename).strip()
+		return None
+
+	def _mountpoint_has_writeback_cache(self, mountpoint):
+		for device in self._mountpoint_topology[mountpoint]["disks"]:
+			if self._get_device_cache_type(device) == "write back":
+				return True
+		return False
+
+	def _mountpoint_has_barriers(self, mountpoint):
+		with open("/proc/mounts") as mounts_file:
+			for line in mounts_file:
+				# device mountpoint filesystem options dump check
+				columns = line.split()
+				if columns[0][0] != "/":
+					continue
+				if columns[1] == mountpoint:
+					option_list = columns[3]
+					break
+			else:
+				return None
+
+		options = option_list.split(",")
+		for option in options:
+			(name, sep, value) = option.partition("=")
+			# nobarrier barrier=0
+			if name == "nobarrier" or (name == "barrier" and value == "0"):
+				return False
+			# barrier barrier=1
+			elif name == "barrier":
+				return True
+		else:
+			# default
+			return True
+
+	def _remount_partition(self, partition, options):
+		remount_command = ["/usr/bin/mount", partition, "-o", "remount,%s" % options]
+		tuned.utils.commands.execute(remount_command)
+
+	@command_custom("disable_barriers", per_device=True)
+	def _disable_barriers(self, start, value, mountpoint):
+		storage_key = self._storage_key("disable_barriers", mountpoint)
+		force = str(value).lower() == "force"
+		value = force or self._config_bool(value)
+
+		if start:
+			if not value:
+				return
+
+			reject_reason = None
+
+			if not force:
+				if mountpoint in ["/", "/boot"]:
+					reject_reason = "system boot protection"
+				elif not self._mountpoint_topology[mountpoint]["filesystem"].startswith("ext"):
+					reject_reason = "filesystem not supported"
+				elif self._mountpoint_has_writeback_cache(mountpoint):
+					reject_reason = "device uses write back cache"
+
+			if reject_reason is None:
+				original_value = self._mountpoint_has_barriers(mountpoint)
+				if original_value is None:
+					reject_reason = "unknown current setting"
+				elif original_value == False:
+					reject_reason = "barriers already disabled"
+
+			if reject_reason is not None:
+				log.info("not disabling barriers on '%s' (%s)" % (mountpoint, reject_reason))
+				return
+
+			self._storage.set(storage_key, original_value)
+			log.info("disabling barriers on '%s'" % mountpoint)
+			self._remount_partition(mountpoint, "barrier=0")
+
+		else:
+			original_value = self._storage.get(storage_key)
+			if original_value is None:
+				return
+
+			log.info("enabling barriers on '%s'" % mountpoint)
+			self._remount_partition(mountpoint, "barrier=1")
+			self._storage.unset(storage_key)