fix: make take snapshot unsafe

Author: bmuddha

magicblock-accounts-db/src/lib.rs

@@ -282,12 +282,15 @@ impl AccountsDb {
     ///
     /// Returns the state checksum computed at snapshot time.
     /// The checksum can be used to verify state consistency across nodes.
-    pub fn take_snapshot(&self, slot: u64) -> AccountsDbResult<u64> {
+    ///
+    ///
+    /// # Safety
+    /// the caller must ensure that no state transitions are taking
+    /// place concurrently when this operation is in progress
+    pub unsafe fn take_snapshot(&self, slot: u64) -> AccountsDbResult<u64> {
         // Create snapshot directory (potential deep copy)
         self.flush();
-        // SAFETY:
-        // we have acquired the write lock above
-        let checksum = unsafe { self.checksum() };
+        let checksum = self.checksum();
         let used_storage = self.storage.active_segment();
 
         let manager = self.snapshot_manager.clone();

magicblock-accounts-db/src/tests.rs

@@ -754,7 +754,7 @@ impl TestEnv {
 
     /// Takes a snapshot and waits for archiving to complete.
     fn take_snapshot_and_wait(&self, slot: u64) -> u64 {
-        let checksum = self.adb.take_snapshot(slot);
+        let checksum = unsafe { self.adb.take_snapshot(slot) };
         // Wait for background archiving to complete
         let mut retries = 0;
         while !self.adb.snapshot_exists(slot) && retries < 200 {