mount/fuse: Make event-history feature configurable

... and disable it by default.

        Backport of:
        > Change-Id: Ia533788d309c78688a315dc8cd04d30fad9e9485
        > Reviewed-on: https://review.gluster.org/18242
        > BUG: 1467614
        > cherry-picked from commit 956d43d6e89d40ee683547003b876f1f456f03b6

This is because having it disabled seems to improve performance.
This could be due to the lock contention by the different epoll threads
on the circular buff lock in the fop cbks just before writing their response
to /dev/fuse.

Just to provide some data - wrt ovirt-gluster hyperconverged
environment, I saw an increase in IOPs by 12K with event-history
disabled for randrom read workload.

Usage:
mount -t glusterfs -o event-history=on $HOSTNAME:$VOLNAME $MOUNTPOINT
OR
glusterfs --event-history=on --volfile-server=$HOSTNAME --volfile-id=$VOLNAME $MOUNTPOINT

Change-Id: Ia533788d309c78688a315dc8cd04d30fad9e9485
BUG: 1495397
Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>

7 files changed, 74 insertions, 15 deletions

diff --git a/glusterfsd/src/glusterfsd.c b/glusterfsd/src/glusterfsd.c
index 78b06bf4701..eeffdc5c34e 100644
--- a/glusterfsd/src/glusterfsd.c
+++ b/glusterfsd/src/glusterfsd.c
@@ -244,6 +244,8 @@ static struct argp_option gf_options[] = {
          "Override default for secure (SSL) management connections"},
         {"localtime-logging", ARGP_LOCALTIME_LOGGING_KEY, 0, 0,
          "Enable localtime logging"},
+        {"event-history", ARGP_FUSE_EVENT_HISTORY_KEY, "BOOL",
+         OPTION_ARG_OPTIONAL, "disable/enable fuse event-history"},
         {0, 0, 0, 0, "Miscellaneous Options:"},
         {0, }
 };
@@ -554,6 +556,15 @@ set_fuse_mount_options (glusterfs_ctx_t *ctx, dict_t *options)
                         goto err;
                 }
         }
+        if (cmd_args->event_history) {
+                ret = dict_set_str (options, "event-history",
+                                    cmd_args->event_history);
+                if (ret < 0) {
+                        gf_msg ("glusterfsd", GF_LOG_ERROR, 0, glusterfsd_msg_4,
+                                "event-history");
+                        goto err;
+                }
+        }
         ret = 0;
 err:
         return ret;
@@ -1287,6 +1298,23 @@ no_oom_api:
                 }
                 cmd_args->subdir_mount = gf_strdup (arg);
                 break;
+        case ARGP_FUSE_EVENT_HISTORY_KEY:
+                if (!arg)
+                        arg = "no";
+
+                if (gf_string2boolean (arg, &b) == 0) {
+                        if (b) {
+                                cmd_args->event_history = "yes";
+                        } else {
+                                cmd_args->event_history = "no";
+                        }
+
+                        break;
+                }
+
+                argp_failure (state, -1, 0,
+                              "unknown event-history setting \"%s\"", arg);
+                break;
 	}
 
         return 0;
diff --git a/glusterfsd/src/glusterfsd.h b/glusterfsd/src/glusterfsd.h
index 871bcf61e58..6d1e16594b1 100644
--- a/glusterfsd/src/glusterfsd.h
+++ b/glusterfsd/src/glusterfsd.h
@@ -98,6 +98,7 @@ enum argp_option_keys {
 #endif
         ARGP_LOCALTIME_LOGGING_KEY        = 177,
         ARGP_SUBDIR_MOUNT_KEY             = 178,
+        ARGP_FUSE_EVENT_HISTORY_KEY       = 179,
 };
 
 struct _gfd_vol_top_priv {
diff --git a/libglusterfs/src/glusterfs.h b/libglusterfs/src/glusterfs.h
index 8dcc4a367d0..18256aad8fc 100644
--- a/libglusterfs/src/glusterfs.h
+++ b/libglusterfs/src/glusterfs.h
@@ -421,6 +421,8 @@ struct _cmd_args {
 
         /* For the subdir mount */
         char           *subdir_mount;
+
+        char              *event_history;
 };
 typedef struct _cmd_args cmd_args_t;
 
diff --git a/tests/bugs/fuse/bug-858215.t b/tests/bugs/fuse/bug-858215.t
index 389783be841..acfaca9bb4b 100755
--- a/tests/bugs/fuse/bug-858215.t
+++ b/tests/bugs/fuse/bug-858215.t
@@ -32,7 +32,7 @@ TEST $CLI volume start $V0;
 EXPECT 'Started' volinfo_field $V0 'Status';
 
 ## Mount FUSE with caching disabled
-TEST glusterfs --entry-timeout=0 --attribute-timeout=0 -s $H0 --volfile-id $V0 $M0;
+TEST glusterfs --entry-timeout=0 --attribute-timeout=0 --event-history=on -s $H0 --volfile-id $V0 $M0;
 
 ## Test for checking whether the fops have been saved in the event-history
 TEST ! stat $M0/newfile;
diff --git a/xlators/mount/fuse/src/fuse-bridge.c b/xlators/mount/fuse/src/fuse-bridge.c
index 4865ffdc562..d7c213425c6 100644
--- a/xlators/mount/fuse/src/fuse-bridge.c
+++ b/xlators/mount/fuse/src/fuse-bridge.c
@@ -5162,10 +5162,15 @@ fuse_priv_dump (xlator_t  *this)
 int
 fuse_history_dump (xlator_t *this)
 {
-        int      ret    = -1;
-        char key_prefix[GF_DUMP_MAX_BUF_LEN] = {0,};
+        int             ret                             = -1;
+        char            key_prefix[GF_DUMP_MAX_BUF_LEN] = {0,};
+        fuse_private_t *priv                            = this->private;
 
         GF_VALIDATE_OR_GOTO ("fuse", this, out);
+
+        if (!priv->event_history)
+                goto out;
+
         GF_VALIDATE_OR_GOTO (this->name, this->history, out);
 
         gf_proc_dump_build_key (key_prefix, "xlator.mount.fuse",
@@ -5660,6 +5665,9 @@ init (xlator_t *this_xl)
                 }
         }
 
+        GF_OPTION_INIT("event-history", priv->event_history, bool,
+                       cleanup_exit);
+
         /* user has set only background-qlen, not congestion-threshold,
            use the fuse kernel driver formula to set congestion. ie, 75% */
         if (dict_get (this_xl->options, "background-qlen") &&
@@ -5758,14 +5766,16 @@ init (xlator_t *this_xl)
                         goto cleanup_exit;
         }
 
-        event = eh_new (FUSE_EVENT_HISTORY_SIZE, _gf_false, NULL);
-        if (!event) {
-                gf_log (this_xl->name, GF_LOG_ERROR,
-                        "could not create a new event history");
-                goto cleanup_exit;
-        }
+        if (priv->event_history) {
+                event = eh_new (FUSE_EVENT_HISTORY_SIZE, _gf_false, NULL);
+                if (!event) {
+                        gf_log (this_xl->name, GF_LOG_ERROR,
+                                "could not create a new event history");
+                        goto cleanup_exit;
+                }
 
-        this_xl->history = event;
+                this_xl->history = event;
+        }
 
         pthread_mutex_init (&priv->fuse_dump_mutex, NULL);
         pthread_cond_init (&priv->sync_cond, NULL);
@@ -5962,5 +5972,11 @@ struct volume_options options[] = {
           .type = GF_OPTION_TYPE_BOOL,
           .default_value = "false"
         },
+        { .key = {"event-history"},
+          .type = GF_OPTION_TYPE_BOOL,
+          .default_value = "false",
+          .description = "This option can be used to enable or disable fuse "
+          "event history.",
+        },
         { .key = {NULL} },
 };
diff --git a/xlators/mount/fuse/src/fuse-bridge.h b/xlators/mount/fuse/src/fuse-bridge.h
index 201b7f6930f..2dfef64c975 100644
--- a/xlators/mount/fuse/src/fuse-bridge.h
+++ b/xlators/mount/fuse/src/fuse-bridge.h
@@ -135,6 +135,9 @@ struct fuse_private {
         /* Enable or disable capability support */
         gf_boolean_t         capability;
 
+        /* Enable or disable event history */
+        gf_boolean_t         event_history;
+
         /* whether to run the unmount daemon */
         gf_boolean_t auto_unmount;
 };
@@ -280,7 +283,8 @@ typedef struct fuse_graph_switch_args fuse_graph_switch_args_t;
 
 #define fuse_log_eh_fop(this, state, frame, op_ret, op_errno)               \
         do {                                                            \
-                if (this->history) {                                    \
+                fuse_private_t *priv = this->private;                   \
+                if (this->history && priv->event_history) {             \
                         if (state->fd)                                  \
                                 gf_log_eh ("op_ret: %d, op_errno: %d, " \
                                            "%"PRIu64", %s () => %p, gfid: %s", \
@@ -300,10 +304,11 @@ typedef struct fuse_graph_switch_args fuse_graph_switch_args_t;
                 }                                                       \
         } while(0)
 
-#define fuse_log_eh(this, args...)              \
-        do {                                    \
-                if (this->history)              \
-                        gf_log_eh(args);        \
+#define fuse_log_eh(this, args...)                            \
+        do {                                                  \
+                fuse_private_t *priv = this->private;         \
+                if (this->history && priv->event_history)     \
+                        gf_log_eh(args);                      \
         } while (0)
 
 static inline xlator_t *
diff --git a/xlators/mount/fuse/utils/mount.glusterfs.in b/xlators/mount/fuse/utils/mount.glusterfs.in
index 409e32163f7..bd6503a04e3 100755
--- a/xlators/mount/fuse/utils/mount.glusterfs.in
+++ b/xlators/mount/fuse/utils/mount.glusterfs.in
@@ -217,6 +217,10 @@ start_glusterfs ()
         cmd_line=$(echo "$cmd_line --use-readdirp=$use_readdirp");
     fi
 
+    if [ -n "$event_history" ]; then
+        cmd_line=$(echo "$cmd_line --event-history=$event_history");
+    fi
+
     if [ -n "$volume_name" ]; then
         cmd_line=$(echo "$cmd_line --volume-name=$volume_name");
     fi
@@ -482,6 +486,9 @@ with_options()
         "use-readdirp")
             use_readdirp=$value
             ;;
+        "event-history")
+            event_history=$value
+            ;;
         "no-root-squash")
             if [ $value = "yes" ] ||
                 [ $value = "on" ] ||