diff options
| -rw-r--r-- | rtslib/root.py | 5 | ||||
| -rw-r--r-- | rtslib/utils.py | 31 |
2 files changed, 35 insertions, 1 deletions
diff --git a/rtslib/root.py b/rtslib/root.py index d558445..13d7f2a 100644 --- a/rtslib/root.py +++ b/rtslib/root.py @@ -28,7 +28,7 @@ from fabric import FabricModule from tcm import (StorageObject, FileIOStorageObject, BlockStorageObject, PSCSIStorageObject, RDMCPStorageObject) from utils import RTSLibError, RTSLibBrokenLink, modprobe, mount_configfs -from utils import dict_remove, set_attributes +from utils import dict_remove, set_attributes, locked storageobjects = dict( fileio=FileIOStorageObject, @@ -126,6 +126,7 @@ class RTSRoot(CFSNode): # RTSRoot public stuff + @locked def dump(self): ''' Returns a dict representing the complete state of the target @@ -140,6 +141,7 @@ class RTSRoot(CFSNode): if f.discovery_enable_auth] return d + @locked def clear_existing(self, confirm=False): ''' Remove entire current configuration. @@ -155,6 +157,7 @@ class RTSRoot(CFSNode): for so in self.storage_objects: so.delete() + @locked def restore(self, config, clear_existing=False, abort_on_error=False): ''' Takes a dict generated by dump() and reconfigures the target to match. diff --git a/rtslib/utils.py b/rtslib/utils.py index 8f86d6d..1f36946 100644 --- a/rtslib/utils.py +++ b/rtslib/utils.py @@ -23,6 +23,8 @@ import stat import uuid import socket import subprocess +import fcntl +import time from contextlib import contextmanager class RTSLibError(Exception): @@ -391,6 +393,35 @@ def ignored(*exceptions): except exceptions: pass +@contextmanager +def file_lock(lock_file, timeout=10): + ''' + A context manager for locking a file, with timeout. + ''' + with open(lock_file, "w") as f: + for x in xrange(timeout): + try: + fcntl.lockf(f, fcntl.LOCK_EX | fcntl.LOCK_NB) + except IOError: + time.sleep(1) + else: + try: + yield + finally: + fcntl.lockf(f, fcntl.LOCK_UN) + break + else: + raise IOError("Acquiring lock timed out after %d seconds" % timeout) + +def locked(func): + ''' + A decorator that enforces mutual exclusion between methods using it. + ''' + def inner(*args, **kwargs): + with file_lock("/var/run/target.lock"): + return func(*args, **kwargs) + return inner + # # These two functions are meant to be used with functools.partial and # properties. |