CA-387861 Wrap dmsetup and multipath with 'multipath' exclusive context

Signed-off-by: Tim Smith <[email protected]>

drivers/lvutil.py

@@ -653,7 +653,8 @@ def activateNoRefcount(path, refresh):
         text = cmd_lvm([CMD_LVCHANGE, "--refresh", path])
         mapperDevice = path[5:].replace("-", "--").replace("/", "-")
         cmd = [CMD_DMSETUP, "table", mapperDevice]
-        ret = util.pread(cmd)
+        with Fairlock("multipath"):
+            ret = util.pread(cmd)
         util.SMlog("DM table for %s: %s" % (path, ret.strip()))
         # Restore slave mode lvm.conf
         os.environ['LVM_SYSTEM_DIR'] = DEF_LVM_CONF
@@ -695,7 +696,8 @@ def _checkActive(path):
     mapperDevice = path[5:].replace("-", "--").replace("/", "-")
     cmd = [CMD_DMSETUP, "status", mapperDevice]
     try:
-        ret = util.pread2(cmd)
+        with Fairlock("multipath"):
+            ret = util.pread2(cmd)
         mapperDeviceExists = True
         util.SMlog("_checkActive: %s: %s" % (mapperDevice, ret))
     except util.CommandException:
@@ -734,7 +736,8 @@ def _lvmBugCleanup(path):
     cmd_rf = [CMD_DMSETUP, "remove", mapperDevice, "--force"]
 
     try:
-        util.pread(cmd_st, expect_rc=1)
+        with Fairlock("multipath"):
+            util.pread(cmd_st, expect_rc=1)
     except util.CommandException as e:
         if e.code == 0:
             nodeExists = True
@@ -749,13 +752,15 @@ def _lvmBugCleanup(path):
         util.SMlog("_lvmBugCleanup: removing dm device %s" % mapperDevice)
         for i in range(LVM_FAIL_RETRIES):
             try:
-                util.pread2(cmd_rm)
+                with Fairlock("multipath"):
+                    util.pread2(cmd_rm)
                 break
             except util.CommandException as e:
                 if i < LVM_FAIL_RETRIES - 1:
                     util.SMlog("Failed on try %d, retrying" % i)
                     try:
-                        util.pread(cmd_st, expect_rc=1)
+                        with Fairlock("multipath"):
+                            util.pread(cmd_st, expect_rc=1)
                         util.SMlog("_lvmBugCleanup: dm device {}"
                                    " removed".format(mapperDevice)
                                    )
@@ -799,7 +804,8 @@ def removeDevMapperEntry(path, strict=True):
         if not strict:
             cmd = [CMD_DMSETUP, "status", path]
             try:
-                util.pread(cmd, expect_rc=1)
+                with Fairlock("multipath"):
+                    util.pread(cmd, expect_rc=1)
                 return True
             except:
                 pass  # Continuining will fail and log the right way

drivers/mpath_cli.py

@@ -18,6 +18,7 @@
 import util
 import re
 import time
+from fairlock import Fairlock
 
 
 class MPathCLIFail(Exception):
@@ -32,7 +33,8 @@ def __str__(self):
 
 def mpexec(cmd):
     util.SMlog("mpath cmd: %s" % cmd)
-    (rc, stdout, stderr) = util.doexec(mpathcmd, cmd)
+    with Fairlock("multipath"):
+        (rc, stdout, stderr) = util.doexec(mpathcmd, cmd)
     if stdout != "multipathd> ok\nmultipathd> " \
             and stdout != "multipathd> " + cmd + "\nok\nmultipathd> ":
         raise MPathCLIFail
@@ -77,7 +79,8 @@ def is_working():
 
 def do_get_topology(cmd):
     util.SMlog("mpath cmd: %s" % cmd)
-    (rc, stdout, stderr) = util.doexec(mpathcmd, cmd)
+    with Fairlock("multipath"):
+        (rc, stdout, stderr) = util.doexec(mpathcmd, cmd)
     util.SMlog("mpath output: %s" % stdout)
     lines = stdout.split('\n')[:-1]
     if len(lines):
@@ -109,7 +112,8 @@ def list_paths(scsi_id):
 def list_maps():
     cmd = "list maps"
     util.SMlog("mpath cmd: %s" % cmd)
-    (rc, stdout, stderr) = util.doexec(mpathcmd, cmd)
+    with Fairlock("multipath"):
+        (rc, stdout, stderr) = util.doexec(mpathcmd, cmd)
     util.SMlog("mpath output: %s" % stdout)
     return [x.split(' ')[0] for x in stdout.split('\n')[2:-1]]
 

drivers/mpath_dmp.py

@@ -23,6 +23,7 @@
 import scsiutil
 import wwid_conf
 import errno
+from fairlock import Fairlock
 
 DMPBIN = "/sbin/multipath"
 DEVMAPPERPATH = "/dev/mapper"
@@ -77,10 +78,11 @@ def _resetDMP(sid, explicit_unmap=False):
 # tables. In that case, list_paths will return [], but remove_map might
 # throw an exception. Catch it and ignore it.
     if explicit_unmap:
-        util.retry(lambda: util.pread2(['/usr/sbin/multipath', '-f', sid]),
-                   maxretry=3, period=4)
-        util.retry(lambda: util.pread2(['/usr/sbin/multipath', '-W']), maxretry=3,
-                   period=4)
+        with Fairlock("multipath"):
+            util.retry(lambda: util.pread2(['/usr/sbin/multipath', '-f', sid]),
+                    maxretry=3, period=4)
+            util.retry(lambda: util.pread2(['/usr/sbin/multipath', '-W']), maxretry=3,
+                    period=4)
     else:
         mpath_cli.ensure_map_gone(sid)
 
@@ -109,33 +111,35 @@ def refresh(sid, npaths):
 def _is_valid_multipath_device(sid):
 
     # Check if device is already multipathed
-    (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-l', sid])
+    with Fairlock("multipath"):
+        (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-l', sid])
     if not stdout + stderr:
-        (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-ll', sid])
+        with Fairlock("multipath"):
+            (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-ll', sid])
     if not stdout + stderr:
-        (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-a', sid])
+        with Fairlock("multipath"):
+            (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-a', sid])
         if ret < 0:
             util.SMlog("Failed to add {}: wwid could be explicitly "
-                       "blacklisted\n Continue with multipath disabled for "
-                       "this SR".format(sid))
+                    "blacklisted\n Continue with multipath disabled for "
+                    "this SR".format(sid))
             return False
 
         by_scsid_path = "/dev/disk/by-scsid/" + sid
         if os.path.exists(by_scsid_path):
             devs = os.listdir(by_scsid_path)
         else:
-            util.SMlog("Device {} is not ready yet, skipping multipath check"
-                       .format(by_scsid_path))
+            util.SMlog("Device {} is not ready yet, skipping multipath check".format(by_scsid_path))
             return False
         ret = 1
         # Some paths might be down, check all associated devices
         for dev in devs:
             devpath = os.path.join(by_scsid_path, dev)
             real_path = util.get_real_path(devpath)
-            (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-c',
-                                                 real_path])
-            if ret == 0:
-                break
+            with Fairlock("multipath"):
+                (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-c', real_path])
+                if ret == 0:
+                    break
 
         if ret == 1:
             # This is very fragile but it is not a good sign to fail without
@@ -146,8 +150,8 @@ def _is_valid_multipath_device(sid):
             if not stdout + stderr:
                 # Attempt to cleanup wwids file before raising
                 try:
-                    (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath',
-                                                         '-w', sid])
+                    with Fairlock("multipath"):
+                        (ret, stdout, stderr) = util.doexec(['/usr/sbin/multipath', '-w', sid])
                 except OSError:
                     util.SMlog("Error removing {} from wwids file".format(sid))
                 raise xs_errors.XenError('MultipathGenericFailure',
@@ -166,10 +170,8 @@ def _refresh_DMP(sid, npaths):
     path = os.path.join(DEVMAPPERPATH, sid)
     # If the mapper path doesn't exist force a reload in multipath
     if not os.path.exists(path):
-        util.retry(lambda: util.pread2(
-            ['/usr/sbin/multipath', '-r', sid]),
-                   maxretry=3,
-                   period=4)
+        with Fairlock("multipath"):
+            util.retry(lambda: util.pread2(['/usr/sbin/multipath', '-r', sid]), maxretry=3, period=4)
         util.wait_for_path(path, 30)
     if not os.path.exists(path):
         raise xs_errors.XenError('MultipathMapperPathMissing',

tests/test_mpath_dmp.py

@@ -30,6 +30,9 @@ def setUp(self):
         mpath_cli_patcher = mock.patch('mpath_dmp.mpath_cli', autospec=True)
         self.mock_mpath_cli = mpath_cli_patcher.start()
 
+        lock_patcher = mock.patch('mpath_dmp.Fairlock', autospec=True)
+        self.mock_lock = lock_patcher.start()
+
         self.addCleanup(mock.patch.stopall)
 
     @testlib.with_context