""" Exercise the MDS's behaviour when clients and the MDCache reach or exceed the limits of how many caps/inodes they should hold. """ import logging from textwrap import dedent from unittest import SkipTest from teuthology.orchestra.run import CommandFailedError from tasks.cephfs.cephfs_test_case import CephFSTestCase, needs_trimming from tasks.cephfs.fuse_mount import FuseMount import os log = logging.getLogger(__name__) # Arbitrary timeouts for operations involving restarting # an MDS or waiting for it to come up MDS_RESTART_GRACE = 60 # Hardcoded values from Server::recall_client_state CAP_RECALL_RATIO = 0.8 CAP_RECALL_MIN = 100 class TestClientLimits(CephFSTestCase): REQUIRE_KCLIENT_REMOTE = True CLIENTS_REQUIRED = 2 def _test_client_pin(self, use_subdir): """ When a client pins an inode in its cache, for example because the file is held open, it should reject requests from the MDS to trim these caps. The MDS should complain to the user that it is unable to enforce its cache size limits because of this objectionable client. :param use_subdir: whether to put test files in a subdir or use root """ cache_size = 100 open_files = 200 self.set_conf('mds', 'mds cache size', cache_size) self.fs.mds_fail_restart() self.fs.wait_for_daemons() mount_a_client_id = self.mount_a.get_global_id() path = "subdir/mount_a" if use_subdir else "mount_a" open_proc = self.mount_a.open_n_background(path, open_files) # Client should now hold: # `open_files` caps for the open files # 1 cap for root # 1 cap for subdir self.wait_until_equal(lambda: self.get_session(mount_a_client_id)['num_caps'], open_files + (2 if use_subdir else 1), timeout=600, reject_fn=lambda x: x > open_files + 2) # MDS should not be happy about that, as the client is failing to comply # with the SESSION_RECALL messages it is being sent mds_recall_state_timeout = int(self.fs.get_config("mds_recall_state_timeout")) self.wait_for_health("failing to respond to cache pressure", mds_recall_state_timeout + 10) # We can also test that the MDS health warning for oversized # cache is functioning as intended. self.wait_for_health("Too many inodes in cache", mds_recall_state_timeout + 10) # When the client closes the files, it should retain only as many caps as allowed # under the SESSION_RECALL policy log.info("Terminating process holding files open") open_proc.stdin.close() try: open_proc.wait() except CommandFailedError: # We killed it, so it raises an error pass # The remaining caps should comply with the numbers sent from MDS in SESSION_RECALL message, # which depend on the cache size and overall ratio self.wait_until_equal( lambda: self.get_session(mount_a_client_id)['num_caps'], int(cache_size * 0.8), timeout=600, reject_fn=lambda x: x < int(cache_size*.8)) @needs_trimming def test_client_pin_root(self): self._test_client_pin(False) @needs_trimming def test_client_pin(self): self._test_client_pin(True) def test_client_release_bug(self): """ When a client has a bug (which we will simulate) preventing it from releasing caps, the MDS should notice that releases are not being sent promptly, and generate a health metric to that effect. """ # The debug hook to inject the failure only exists in the fuse client if not isinstance(self.mount_a, FuseMount): raise SkipTest("Require FUSE client to inject client release failure") self.set_conf('client.{0}'.format(self.mount_a.client_id), 'client inject release failure', 'true') self.mount_a.teardown() self.mount_a.mount() self.mount_a.wait_until_mounted() mount_a_client_id = self.mount_a.get_global_id() # Client A creates a file. He will hold the write caps on the file, and later (simulated bug) fail # to comply with the MDSs request to release that cap self.mount_a.run_shell(["touch", "file1"]) # Client B tries to stat the file that client A created rproc = self.mount_b.write_background("file1") # After mds_revoke_cap_timeout, we should see a health warning (extra lag from # MDS beacon period) mds_revoke_cap_timeout = int(self.fs.get_config("mds_revoke_cap_timeout")) self.wait_for_health("failing to respond to capability release", mds_revoke_cap_timeout + 10) # Client B should still be stuck self.assertFalse(rproc.finished) # Kill client A self.mount_a.kill() self.mount_a.kill_cleanup() # Client B should complete self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id]) rproc.wait() def test_client_oldest_tid(self): """ When a client does not advance its oldest tid, the MDS should notice that and generate health warnings. """ # num of requests client issues max_requests = 1000 # The debug hook to inject the failure only exists in the fuse client if not isinstance(self.mount_a, FuseMount): raise SkipTest("Require FUSE client to inject client release failure") self.set_conf('client', 'client inject fixed oldest tid', 'true') self.mount_a.teardown() self.mount_a.mount() self.mount_a.wait_until_mounted() self.fs.mds_asok(['config', 'set', 'mds_max_completed_requests', '{0}'.format(max_requests)]) # Create lots of files self.mount_a.create_n_files("testdir/file1", max_requests + 100) # Create a few files synchronously. This makes sure previous requests are completed self.mount_a.create_n_files("testdir/file2", 5, True) # Wait for the health warnings. Assume mds can handle 10 request per second at least self.wait_for_health("failing to advance its oldest client/flush tid", max_requests / 10) def _test_client_cache_size(self, mount_subdir): """ check if client invalidate kernel dcache according to its cache size config """ # The debug hook to inject the failure only exists in the fuse client if not isinstance(self.mount_a, FuseMount): raise SkipTest("Require FUSE client to inject client release failure") if mount_subdir: # fuse assigns a fix inode number (1) to root inode. But in mounting into # subdir case, the actual inode number of root is not 1. This mismatch # confuses fuse_lowlevel_notify_inval_entry() when invalidating dentries # in root directory. self.mount_a.run_shell(["mkdir", "subdir"]) self.mount_a.umount_wait() self.set_conf('client', 'client mountpoint', '/subdir') self.mount_a.mount() self.mount_a.wait_until_mounted() root_ino = self.mount_a.path_to_ino(".") self.assertEqual(root_ino, 1); dir_path = os.path.join(self.mount_a.mountpoint, "testdir") mkdir_script = dedent(""" import os os.mkdir("{path}") for n in range(0, {num_dirs}): os.mkdir("{path}/dir{{0}}".format(n)) """) num_dirs = 1000 self.mount_a.run_python(mkdir_script.format(path=dir_path, num_dirs=num_dirs)) self.mount_a.run_shell(["sync"]) dentry_count, dentry_pinned_count = self.mount_a.get_dentry_count() self.assertGreaterEqual(dentry_count, num_dirs) self.assertGreaterEqual(dentry_pinned_count, num_dirs) cache_size = num_dirs / 10 self.mount_a.set_cache_size(cache_size) def trimmed(): dentry_count, dentry_pinned_count = self.mount_a.get_dentry_count() log.info("waiting, dentry_count, dentry_pinned_count: {0}, {1}".format( dentry_count, dentry_pinned_count )) if dentry_count > cache_size or dentry_pinned_count > cache_size: return False return True self.wait_until_true(trimmed, 30) @needs_trimming def test_client_cache_size(self): self._test_client_cache_size(False) self._test_client_cache_size(True)