From 71b12b1f56f637abdb0f015f6497e9cf2197d379 Mon Sep 17 00:00:00 2001
From: Yueh-Hsuan Chiang <93241502+yhchiang-sol@users.noreply.github.com>
Date: Wed, 15 Dec 2021 00:37:09 -0800
Subject: [PATCH] Add comment for clear_unconfirmed_slot() in blockstore.rs
 (#21837)

---
 ledger/src/blockstore.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/ledger/src/blockstore.rs b/ledger/src/blockstore.rs
index aedd12d8e..90dd9ada8 100644
--- a/ledger/src/blockstore.rs
+++ b/ledger/src/blockstore.rs
@@ -972,6 +972,13 @@ impl Blockstore {
         Ok((newly_completed_data_sets, inserted_indices))
     }
 
+    /// Range-delete all entries which prefix matches the specified `slot` and
+    /// clear all the related `SlotMeta` except its next_slots.
+    ///
+    /// This function currently requires `insert_shreds_lock`, as both
+    /// `clear_unconfirmed_slot()` and `insert_shreds_handle_duplicate()`
+    /// try to perform read-modify-write operation on [`cf::SlotMeta`] column
+    /// family.
     pub fn clear_unconfirmed_slot(&self, slot: Slot) {
         let _lock = self.insert_shreds_lock.lock().unwrap();
         if let Some(mut slot_meta) = self