glusterfs/SOURCES/0445-feature-changelog-Avoid-thread-creation-if-xlator-is.patch

From dc03340654d921916ac3890d713fc84ef4bb1e28 Mon Sep 17 00:00:00 2001
From: Mohit Agrawal <moagrawal@redhat.com>
Date: Sat, 29 Sep 2018 13:15:35 +0530
Subject: [PATCH 445/449] feature/changelog: Avoid thread creation if xlator is
 not enabled

Problem:
Changelog creates threads even if the changelog is not enabled

Background:
Changelog xlator broadly does two things
  1. Journalling - Cosumers are geo-rep and glusterfind
  2. Event Notification for registered events like (open, release etc) -
     Consumers are bitrot, geo-rep

The existing option "changelog.changelog" controls journalling and
there is no option to control event notification and is enabled by
default. So when bitrot/geo-rep is not enabled on the volume, threads
and resources(rpc and rbuf) related to event notifications consumes
resources and cpu cycle which is unnecessary.

Solution:
The solution is to have two different options as below.
 1. changelog-notification : Event notifications
 2. changelog : Journalling

This patch introduces the option "changelog-notification" which is
not exposed to user. When either bitrot or changelog (journalling)
is enabled, it internally enbales 'changelog-notification'. But
once the 'changelog-notification' is enabled, it will not be disabled
for the life time of the brick process even after bitrot and changelog
is disabled. As of now, rpc resource cleanup has lot of races and is
difficult to cleanup cleanly. If allowed, it leads to memory leaks
and crashes on enable/disable of bitrot or changelog (journal) in a
loop. Hence to be safer, the event notification is not disabled within
lifetime of process once enabled.

> Change-Id: Ifd00286e0966049e8eb9f21567fe407cf11bb02a
> Updates: #475
> Signed-off-by: Mohit Agrawal <moagrawal@redhat.com>
> (Cherry pick from commit 6de80bcd6366778ac34ce58ec496fa08cc02bd0b)
> (Reviewed on upstream link https://review.gluster.org/#/c/glusterfs/+/21896/)

BUG: 1790336
Change-Id: Ifd00286e0966049e8eb9f21567fe407cf11bb02a
Signed-off-by: Mohit Agrawal <moagrawal@redhat.com>
Reviewed-on: https://code.engineering.redhat.com/gerrit/202778
Tested-by: Mohit Agrawal <moagrawa@redhat.com>
Tested-by: RHGS Build Bot <nigelb@redhat.com>
Reviewed-by: Sunil Kumar Heggodu Gopala Acharya <sheggodu@redhat.com>
---
 rpc/rpc-lib/src/rpcsvc.c                           |  26 ++--
 tests/basic/changelog/changelog-history.t          |  12 +-
 tests/bugs/bitrot/bug-1227996.t                    |   1 -
 tests/bugs/bitrot/bug-1245981.t                    |   4 +-
 xlators/features/changelog/src/changelog-helpers.h |   4 +
 .../features/changelog/src/changelog-rpc-common.c  |   3 +
 xlators/features/changelog/src/changelog.c         | 149 +++++++++++++++------
 xlators/mgmt/glusterd/src/glusterd-volgen.c        |  13 ++
 8 files changed, 154 insertions(+), 58 deletions(-)

diff --git a/rpc/rpc-lib/src/rpcsvc.c b/rpc/rpc-lib/src/rpcsvc.c
index b058932..3f184bf 100644
--- a/rpc/rpc-lib/src/rpcsvc.c
+++ b/rpc/rpc-lib/src/rpcsvc.c
@@ -1865,6 +1865,18 @@ rpcsvc_program_unregister(rpcsvc_t *svc, rpcsvc_program_t *program)
         goto out;
     }
 
+    pthread_rwlock_rdlock(&svc->rpclock);
+    {
+        list_for_each_entry(prog, &svc->programs, program)
+        {
+            if ((prog->prognum == program->prognum) &&
+                (prog->progver == program->progver)) {
+                break;
+            }
+        }
+    }
+    pthread_rwlock_unlock(&svc->rpclock);
+
     ret = rpcsvc_program_unregister_portmap(program);
     if (ret == -1) {
         gf_log(GF_RPCSVC, GF_LOG_ERROR,
@@ -1881,17 +1893,6 @@ rpcsvc_program_unregister(rpcsvc_t *svc, rpcsvc_program_t *program)
         goto out;
     }
 #endif
-    pthread_rwlock_rdlock(&svc->rpclock);
-    {
-        list_for_each_entry(prog, &svc->programs, program)
-        {
-            if ((prog->prognum == program->prognum) &&
-                (prog->progver == program->progver)) {
-                break;
-            }
-        }
-    }
-    pthread_rwlock_unlock(&svc->rpclock);
 
     gf_log(GF_RPCSVC, GF_LOG_DEBUG,
            "Program unregistered: %s, Num: %d,"
@@ -1912,6 +1913,9 @@ rpcsvc_program_unregister(rpcsvc_t *svc, rpcsvc_program_t *program)
 
     ret = 0;
 out:
+    if (prog)
+        GF_FREE(prog);
+
     if (ret == -1) {
         if (program) {
             gf_log(GF_RPCSVC, GF_LOG_ERROR,
diff --git a/tests/basic/changelog/changelog-history.t b/tests/basic/changelog/changelog-history.t
index 3ce4098..b56e247 100644
--- a/tests/basic/changelog/changelog-history.t
+++ b/tests/basic/changelog/changelog-history.t
@@ -5,6 +5,7 @@
 
 cleanup;
 
+SCRIPT_TIMEOUT=300
 HISTORY_BIN_PATH=$(dirname $0)/../../utils/changelog
 build_tester $HISTORY_BIN_PATH/get-history.c -lgfchangelog
 
@@ -68,18 +69,21 @@ TEST $CLI volume set $V0 changelog.changelog off
 sleep 3
 time_after_disable=$(date '+%s')
 
+TEST $CLI volume set $V0 changelog.changelog on
+sleep 5
+
 #Passes, gives the changelogs till continuous changelogs are available
 # but returns 1
-EXPECT "1" $HISTORY_BIN_PATH/get-history $time_after_enable1 $time_in_sec_htime2
+EXPECT_WITHIN 10 "1" $HISTORY_BIN_PATH/get-history $time_after_enable1 $time_in_sec_htime2
 
 #Fails as start falls between htime files
-EXPECT "-3" $HISTORY_BIN_PATH/get-history $time_between_htime $time_in_sec_htime1
+EXPECT_WITHIN 10 "-3" $HISTORY_BIN_PATH/get-history $time_between_htime $time_in_sec_htime1
 
 #Passes as start and end falls in same htime file
-EXPECT "0" $HISTORY_BIN_PATH/get-history $time_in_sec_htime1 $time_in_sec_htime2
+EXPECT_WITHIN 10 "0" $HISTORY_BIN_PATH/get-history $time_in_sec_htime1 $time_in_sec_htime2
 
 #Passes, gives the changelogs till continuous changelogs are available
-EXPECT "0" $HISTORY_BIN_PATH/get-history $time_in_sec_htime2 $time_after_disable
+EXPECT_WITHIN 10 "0" $HISTORY_BIN_PATH/get-history $time_in_sec_htime2 $time_after_disable
 
 TEST rm $HISTORY_BIN_PATH/get-history
 
diff --git a/tests/bugs/bitrot/bug-1227996.t b/tests/bugs/bitrot/bug-1227996.t
index 47ebc42..121c7b5 100644
--- a/tests/bugs/bitrot/bug-1227996.t
+++ b/tests/bugs/bitrot/bug-1227996.t
@@ -17,7 +17,6 @@ TEST pidof glusterd;
 ## Lets create and start the volume
 TEST $CLI volume create $V0 $H0:$B0/${V0}0 $H0:$B0/${V0}1
 TEST $CLI volume start $V0
-
 ## Enable bitrot on volume $V0
 TEST $CLI volume bitrot $V0 enable
 
diff --git a/tests/bugs/bitrot/bug-1245981.t b/tests/bugs/bitrot/bug-1245981.t
index 2bed4d9..f395525 100644
--- a/tests/bugs/bitrot/bug-1245981.t
+++ b/tests/bugs/bitrot/bug-1245981.t
@@ -47,9 +47,9 @@ touch $M0/5
 sleep `expr $SLEEP_TIME \* 2`
 
 backpath=$(get_backend_paths $fname)
-TEST getfattr -m . -n trusted.bit-rot.signature $backpath
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT 'trusted.bit-rot.signature' check_for_xattr 'trusted.bit-rot.signature' $backpath
 
 backpath=$(get_backend_paths $M0/new_file)
-TEST getfattr -m . -n trusted.bit-rot.signature $backpath
+EXPECT_WITHIN $PROCESS_UP_TIMEOUT 'trusted.bit-rot.signature' check_for_xattr 'trusted.bit-rot.signature' $backpath
 
 cleanup;
diff --git a/xlators/features/changelog/src/changelog-helpers.h b/xlators/features/changelog/src/changelog-helpers.h
index 517c4dc..3afacc9 100644
--- a/xlators/features/changelog/src/changelog-helpers.h
+++ b/xlators/features/changelog/src/changelog-helpers.h
@@ -190,8 +190,12 @@ typedef struct changelog_ev_selector {
 
 /* changelog's private structure */
 struct changelog_priv {
+    /* changelog journalling */
     gf_boolean_t active;
 
+    /* changelog live notifications */
+    gf_boolean_t rpc_active;
+
     /* to generate unique socket file per brick */
     char *changelog_brick;
 
diff --git a/xlators/features/changelog/src/changelog-rpc-common.c b/xlators/features/changelog/src/changelog-rpc-common.c
index dcdcfb1..f2d1853 100644
--- a/xlators/features/changelog/src/changelog-rpc-common.c
+++ b/xlators/features/changelog/src/changelog-rpc-common.c
@@ -263,6 +263,9 @@ changelog_rpc_server_destroy(xlator_t *this, rpcsvc_t *rpc, char *sockfile,
     struct rpcsvc_program *prog = NULL;
     rpc_transport_t *trans = NULL;
 
+    if (!rpc)
+        return;
+
     while (*progs) {
         prog = *progs;
         (void)rpcsvc_program_unregister(rpc, prog);
diff --git a/xlators/features/changelog/src/changelog.c b/xlators/features/changelog/src/changelog.c
index d9025f3..ff06c09 100644
--- a/xlators/features/changelog/src/changelog.c
+++ b/xlators/features/changelog/src/changelog.c
@@ -34,6 +34,12 @@ static struct changelog_bootstrap cb_bootstrap[] = {
     },
 };
 
+static int
+changelog_init_rpc(xlator_t *this, changelog_priv_t *priv);
+
+static int
+changelog_init(xlator_t *this, changelog_priv_t *priv);
+
 /* Entry operations - TYPE III */
 
 /**
@@ -2008,6 +2014,11 @@ notify(xlator_t *this, int event, void *data, ...)
     uint64_t clntcnt = 0;
     changelog_clnt_t *conn = NULL;
     gf_boolean_t cleanup_notify = _gf_false;
+    char sockfile[UNIX_PATH_MAX] = {
+        0,
+    };
+    rpcsvc_listener_t *listener = NULL;
+    rpcsvc_listener_t *next = NULL;
 
     INIT_LIST_HEAD(&queue);
 
@@ -2021,23 +2032,40 @@ notify(xlator_t *this, int event, void *data, ...)
                "cleanup changelog rpc connection of brick %s",
                priv->victim->name);
 
-        this->cleanup_starting = 1;
-        changelog_destroy_rpc_listner(this, priv);
-        conn = &priv->connections;
-        if (conn)
-            changelog_ev_cleanup_connections(this, conn);
-        xprtcnt = GF_ATOMIC_GET(priv->xprtcnt);
-        clntcnt = GF_ATOMIC_GET(priv->clntcnt);
-
-        if (!xprtcnt && !clntcnt) {
-            LOCK(&priv->lock);
-            {
-                cleanup_notify = priv->notify_down;
-                priv->notify_down = _gf_true;
+        if (priv->rpc_active) {
+            this->cleanup_starting = 1;
+            changelog_destroy_rpc_listner(this, priv);
+            conn = &priv->connections;
+            if (conn)
+                changelog_ev_cleanup_connections(this, conn);
+            xprtcnt = GF_ATOMIC_GET(priv->xprtcnt);
+            clntcnt = GF_ATOMIC_GET(priv->clntcnt);
+            if (!xprtcnt && !clntcnt) {
+                LOCK(&priv->lock);
+                {
+                    cleanup_notify = priv->notify_down;
+                    priv->notify_down = _gf_true;
+                }
+                UNLOCK(&priv->lock);
+                list_for_each_entry_safe(listener, next, &priv->rpc->listeners,
+                                         list)
+                {
+                    if (listener->trans) {
+                        rpc_transport_unref(listener->trans);
+                    }
+                }
+                CHANGELOG_MAKE_SOCKET_PATH(priv->changelog_brick, sockfile,
+                                           UNIX_PATH_MAX);
+                sys_unlink(sockfile);
+                if (priv->rpc) {
+                    rpcsvc_destroy(priv->rpc);
+                    priv->rpc = NULL;
+                }
+                if (!cleanup_notify)
+                    default_notify(this, GF_EVENT_PARENT_DOWN, data);
             }
-            UNLOCK(&priv->lock);
-            if (!cleanup_notify)
-                default_notify(this, GF_EVENT_PARENT_DOWN, data);
+        } else {
+            default_notify(this, GF_EVENT_PARENT_DOWN, data);
         }
         goto out;
     }
@@ -2425,6 +2453,22 @@ changelog_barrier_pthread_destroy(changelog_priv_t *priv)
     LOCK_DESTROY(&priv->bflags.lock);
 }
 
+static void
+changelog_cleanup_rpc(xlator_t *this, changelog_priv_t *priv)
+{
+    /* terminate rpc server */
+    if (!this->cleanup_starting)
+        changelog_destroy_rpc_listner(this, priv);
+
+    (void)changelog_cleanup_rpc_threads(this, priv);
+    /* cleanup rot buffs */
+    rbuf_dtor(priv->rbuf);
+
+    /* cleanup poller thread */
+    if (priv->poller)
+        (void)changelog_thread_cleanup(this, priv->poller);
+}
+
 int
 reconfigure(xlator_t *this, dict_t *options)
 {
@@ -2433,6 +2477,9 @@ reconfigure(xlator_t *this, dict_t *options)
     changelog_priv_t *priv = NULL;
     gf_boolean_t active_earlier = _gf_true;
     gf_boolean_t active_now = _gf_true;
+    gf_boolean_t rpc_active_earlier = _gf_true;
+    gf_boolean_t rpc_active_now = _gf_true;
+    gf_boolean_t iniate_rpc = _gf_false;
     changelog_time_slice_t *slice = NULL;
     changelog_log_data_t cld = {
         0,
@@ -2454,6 +2501,7 @@ reconfigure(xlator_t *this, dict_t *options)
 
     ret = -1;
     active_earlier = priv->active;
+    rpc_active_earlier = priv->rpc_active;
 
     /* first stop the rollover and the fsync thread */
     changelog_cleanup_helper_threads(this, priv);
@@ -2487,6 +2535,29 @@ reconfigure(xlator_t *this, dict_t *options)
         goto out;
 
     GF_OPTION_RECONF("changelog", active_now, options, bool, out);
+    GF_OPTION_RECONF("changelog-notification", rpc_active_now, options, bool,
+                     out);
+
+    /* If journalling is enabled, enable rpc notifications */
+    if (active_now && !active_earlier) {
+        if (!rpc_active_earlier)
+            iniate_rpc = _gf_true;
+    }
+
+    if (rpc_active_now && !rpc_active_earlier) {
+        iniate_rpc = _gf_true;
+    }
+
+    /* TODO: Disable of changelog-notifications is not supported for now
+     * as there is no clean way of cleaning up of rpc resources
+     */
+
+    if (iniate_rpc) {
+        ret = changelog_init_rpc(this, priv);
+        if (ret)
+            goto out;
+        priv->rpc_active = _gf_true;
+    }
 
     /**
      * changelog_handle_change() handles changes that could possibly
@@ -2618,6 +2689,7 @@ changelog_init_options(xlator_t *this, changelog_priv_t *priv)
         goto dealloc_2;
 
     GF_OPTION_INIT("changelog", priv->active, bool, dealloc_2);
+    GF_OPTION_INIT("changelog-notification", priv->rpc_active, bool, dealloc_2);
     GF_OPTION_INIT("capture-del-path", priv->capture_del_path, bool, dealloc_2);
 
     GF_OPTION_INIT("op-mode", tmp, str, dealloc_2);
@@ -2656,22 +2728,6 @@ error_return:
     return -1;
 }
 
-static void
-changelog_cleanup_rpc(xlator_t *this, changelog_priv_t *priv)
-{
-    /* terminate rpc server */
-    if (!this->cleanup_starting)
-        changelog_destroy_rpc_listner(this, priv);
-
-    (void)changelog_cleanup_rpc_threads(this, priv);
-    /* cleanup rot buffs */
-    rbuf_dtor(priv->rbuf);
-
-    /* cleanup poller thread */
-    if (priv->poller)
-        (void)changelog_thread_cleanup(this, priv->poller);
-}
-
 static int
 changelog_init_rpc(xlator_t *this, changelog_priv_t *priv)
 {
@@ -2768,10 +2824,13 @@ init(xlator_t *this)
     INIT_LIST_HEAD(&priv->queue);
     priv->barrier_enabled = _gf_false;
 
-    /* RPC ball rolling.. */
-    ret = changelog_init_rpc(this, priv);
-    if (ret)
-        goto cleanup_barrier;
+    if (priv->rpc_active || priv->active) {
+        /* RPC ball rolling.. */
+        ret = changelog_init_rpc(this, priv);
+        if (ret)
+            goto cleanup_barrier;
+        priv->rpc_active = _gf_true;
+    }
 
     ret = changelog_init(this, priv);
     if (ret)
@@ -2783,7 +2842,9 @@ init(xlator_t *this)
     return 0;
 
 cleanup_rpc:
-    changelog_cleanup_rpc(this, priv);
+    if (priv->rpc_active) {
+        changelog_cleanup_rpc(this, priv);
+    }
 cleanup_barrier:
     changelog_barrier_pthread_destroy(priv);
 cleanup_options:
@@ -2808,9 +2869,10 @@ fini(xlator_t *this)
     priv = this->private;
 
     if (priv) {
-        /* terminate RPC server/threads */
-        changelog_cleanup_rpc(this, priv);
-
+        if (priv->active || priv->rpc_active) {
+            /* terminate RPC server/threads */
+            changelog_cleanup_rpc(this, priv);
+        }
         /* call barrier_disable to cancel timer */
         if (priv->barrier_enabled)
             __chlog_barrier_disable(this, &queue);
@@ -2879,6 +2941,13 @@ struct volume_options options[] = {
      .flags = OPT_FLAG_SETTABLE,
      .level = OPT_STATUS_BASIC,
      .tags = {"journal", "georep", "glusterfind"}},
+    {.key = {"changelog-notification"},
+     .type = GF_OPTION_TYPE_BOOL,
+     .default_value = "off",
+     .description = "enable/disable changelog live notification",
+     .op_version = {3},
+     .level = OPT_STATUS_BASIC,
+     .tags = {"bitrot", "georep"}},
     {.key = {"changelog-brick"},
      .type = GF_OPTION_TYPE_PATH,
      .description = "brick path to generate unique socket file name."
diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index 16346e7..13f84ea 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -1876,6 +1876,19 @@ brick_graph_add_changelog(volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
     ret = xlator_set_fixed_option(xl, "changelog-dir", changelog_basepath);
     if (ret)
         goto out;
+
+    ret = glusterd_is_bitrot_enabled(volinfo);
+    if (ret == -1) {
+        goto out;
+    } else if (ret) {
+        ret = xlator_set_fixed_option(xl, "changelog-notification", "on");
+        if (ret)
+            goto out;
+    } else {
+        ret = xlator_set_fixed_option(xl, "changelog-notification", "off");
+        if (ret)
+            goto out;
+    }
 out:
     return ret;
 }
-- 
1.8.3.1