upcall: Avoid sending notifications for invalid inodes

For nameless LOOKUPs, server creates a new inode which shall
remain invalid until the fop is successfully processed post
which it is linked to the inode table.

But incase if there is an already linked inode for that entry,
it discards that newly created inode which results in upcall
notification. This may result in client being bombarded with
unnecessary upcalls affecting performance if the data set is huge.

This issue can be avoided by looking up and storing the upcall
context in the original linked inode (if exists), thus saving up on
those extra callbacks.

This is backport of below mainline fix -
 https://review.gluster.org/22840

Change-Id: I044a1737819bb40d1a049d2f53c0566e746d2a17
fixes: bz#1729221
Signed-off-by: Soumya Koduri <skoduri@redhat.com>

1 files changed, 19 insertions, 2 deletions

diff --git a/xlators/features/upcall/src/upcall-internal.c b/xlators/features/upcall/src/upcall-internal.c
index d8131a9f2ab..f9d8113b74a 100644
--- a/xlators/features/upcall/src/upcall-internal.c
+++ b/xlators/features/upcall/src/upcall-internal.c
@@ -545,6 +545,7 @@ upcall_cache_invalidate (call_frame_t *frame, xlator_t *this, client_t *client,
         upcall_client_t *tmp             = NULL;
         upcall_inode_ctx_t *up_inode_ctx = NULL;
         gf_boolean_t     found           = _gf_false;
+        inode_t *linked_inode = NULL;
 
         if (!is_upcall_enabled(this))
                 return;
@@ -557,8 +558,21 @@ upcall_cache_invalidate (call_frame_t *frame, xlator_t *this, client_t *client,
                 return;
         }
 
-        if (inode)
-                up_inode_ctx = upcall_inode_ctx_get (inode, this);
+        /* For nameless LOOKUPs, inode created shall always be
+         * invalid. Hence check if there is any already linked inode.
+         * If yes, update the inode_ctx of that valid inode
+         */
+        if (inode && (inode->ia_type == IA_INVAL) && stbuf) {
+                linked_inode = inode_find(inode->table, stbuf->ia_gfid);
+                if (linked_inode) {
+                    gf_log("upcall", GF_LOG_DEBUG,
+                           "upcall_inode_ctx_get of linked inode (%p)", inode);
+                    up_inode_ctx = upcall_inode_ctx_get(linked_inode, this);
+                }
+        }
+
+        if (inode && !up_inode_ctx)
+                up_inode_ctx = upcall_inode_ctx_get(inode, this);
 
         if (!up_inode_ctx) {
                 gf_msg ("upcall", GF_LOG_WARNING, 0,
@@ -633,6 +647,9 @@ upcall_cache_invalidate (call_frame_t *frame, xlator_t *this, client_t *client,
         }
         pthread_mutex_unlock (&up_inode_ctx->client_list_lock);
 out:
+        /* release the ref from inode_find */
+        if (linked_inode)
+                inode_unref(linked_inode);
         return;
 }