[TieredStorage] Use OwnerOffset type in TieredAccountMeta (#34106)

#### Problem
TieredAccountMeta currently uses `u32` for owner_offset, while
we already have a dedicate type for that --- OwnerOffset.

#### Summary of Changes
This PR makes TieredAccountMeta use OwnerOffset for its
owner_offset field.

#### Test Plan
Existing unit-tests.

accounts-db/src/tiered_storage/hot.rs

@@ -34,7 +34,7 @@ pub const HOT_FORMAT: TieredStorageFormat = TieredStorageFormat {
 const MAX_HOT_PADDING: u8 = 7;
 
 /// The maximum allowed value for the owner index of a hot account.
-const MAX_HOT_OWNER_INDEX: u32 = (1 << 29) - 1;
+const MAX_HOT_OWNER_OFFSET: OwnerOffset = OwnerOffset((1 << 29) - 1);
 
 #[bitfield(bits = 32)]
 #[repr(C)]
@@ -51,7 +51,7 @@ struct HotMetaPackedFields {
     /// in its hot account entry.
     padding: B3,
     /// The index to the owner of a hot account inside an AccountsFile.
-    owner_index: B29,
+    owner_offset: B29,
 }
 
 /// The storage and in-memory representation of the metadata entry for a
@@ -94,11 +94,11 @@ impl TieredAccountMeta for HotAccountMeta {
     }
 
     /// A builder function that initializes the owner's index.
-    fn with_owner_index(mut self, owner_index: u32) -> Self {
-        if owner_index > MAX_HOT_OWNER_INDEX {
-            panic!("owner_index exceeds MAX_HOT_OWNER_INDEX");
+    fn with_owner_offset(mut self, owner_offset: OwnerOffset) -> Self {
+        if owner_offset > MAX_HOT_OWNER_OFFSET {
+            panic!("owner_offset exceeds MAX_HOT_OWNER_OFFSET");
         }
-        self.packed_fields.set_owner_index(owner_index);
+        self.packed_fields.set_owner_offset(owner_offset.0);
         self
     }
 
@@ -127,8 +127,8 @@ impl TieredAccountMeta for HotAccountMeta {
     }
 
     /// Returns the index to the accounts' owner in the current AccountsFile.
-    fn owner_index(&self) -> u32 {
-        self.packed_fields.owner_index()
+    fn owner_offset(&self) -> OwnerOffset {
+        OwnerOffset(self.packed_fields.owner_offset())
     }
 
     /// Returns the AccountMetaFlags of the current meta.
@@ -285,31 +285,31 @@ pub mod tests {
     #[test]
     fn test_packed_fields() {
         const TEST_PADDING: u8 = 7;
-        const TEST_OWNER_INDEX: u32 = 0x1fff_ef98;
+        const TEST_OWNER_OFFSET: u32 = 0x1fff_ef98;
         let mut packed_fields = HotMetaPackedFields::default();
         packed_fields.set_padding(TEST_PADDING);
-        packed_fields.set_owner_index(TEST_OWNER_INDEX);
+        packed_fields.set_owner_offset(TEST_OWNER_OFFSET);
         assert_eq!(packed_fields.padding(), TEST_PADDING);
-        assert_eq!(packed_fields.owner_index(), TEST_OWNER_INDEX);
+        assert_eq!(packed_fields.owner_offset(), TEST_OWNER_OFFSET);
     }
 
     #[test]
     fn test_packed_fields_max_values() {
         let mut packed_fields = HotMetaPackedFields::default();
         packed_fields.set_padding(MAX_HOT_PADDING);
-        packed_fields.set_owner_index(MAX_HOT_OWNER_INDEX);
+        packed_fields.set_owner_offset(MAX_HOT_OWNER_OFFSET.0);
         assert_eq!(packed_fields.padding(), MAX_HOT_PADDING);
-        assert_eq!(packed_fields.owner_index(), MAX_HOT_OWNER_INDEX);
+        assert_eq!(packed_fields.owner_offset(), MAX_HOT_OWNER_OFFSET.0);
     }
 
     #[test]
     fn test_hot_meta_max_values() {
         let meta = HotAccountMeta::new()
             .with_account_data_padding(MAX_HOT_PADDING)
-            .with_owner_index(MAX_HOT_OWNER_INDEX);
+            .with_owner_offset(MAX_HOT_OWNER_OFFSET);
 
         assert_eq!(meta.account_data_padding(), MAX_HOT_PADDING);
-        assert_eq!(meta.owner_index(), MAX_HOT_OWNER_INDEX);
+        assert_eq!(meta.owner_offset(), MAX_HOT_OWNER_OFFSET);
     }
 
     #[test]
@@ -319,16 +319,16 @@ pub mod tests {
     }
 
     #[test]
-    #[should_panic(expected = "owner_index exceeds MAX_HOT_OWNER_INDEX")]
-    fn test_hot_meta_owner_index_exceeds_limit() {
-        HotAccountMeta::new().with_owner_index(MAX_HOT_OWNER_INDEX + 1);
+    #[should_panic(expected = "owner_offset exceeds MAX_HOT_OWNER_OFFSET")]
+    fn test_hot_meta_owner_offset_exceeds_limit() {
+        HotAccountMeta::new().with_owner_offset(OwnerOffset(MAX_HOT_OWNER_OFFSET.0 + 1));
     }
 
     #[test]
     fn test_hot_account_meta() {
         const TEST_LAMPORTS: u64 = 2314232137;
         const TEST_PADDING: u8 = 5;
-        const TEST_OWNER_INDEX: u32 = 0x1fef_1234;
+        const TEST_OWNER_OFFSET: OwnerOffset = OwnerOffset(0x1fef_1234);
         const TEST_RENT_EPOCH: Epoch = 7;
 
         let optional_fields = AccountMetaOptionalFields {
@@ -340,12 +340,12 @@ pub mod tests {
         let meta = HotAccountMeta::new()
             .with_lamports(TEST_LAMPORTS)
             .with_account_data_padding(TEST_PADDING)
-            .with_owner_index(TEST_OWNER_INDEX)
+            .with_owner_offset(TEST_OWNER_OFFSET)
             .with_flags(&flags);
 
         assert_eq!(meta.lamports(), TEST_LAMPORTS);
         assert_eq!(meta.account_data_padding(), TEST_PADDING);
-        assert_eq!(meta.owner_index(), TEST_OWNER_INDEX);
+        assert_eq!(meta.owner_offset(), TEST_OWNER_OFFSET);
         assert_eq!(*meta.flags(), flags);
     }
 
@@ -355,7 +355,7 @@ pub mod tests {
         let padding = [0u8; 5];
 
         const TEST_LAMPORT: u64 = 2314232137;
-        const OWNER_INDEX: u32 = 0x1fef_1234;
+        const OWNER_OFFSET: u32 = 0x1fef_1234;
         const TEST_RENT_EPOCH: Epoch = 7;
 
         let optional_fields = AccountMetaOptionalFields {
@@ -367,7 +367,7 @@ pub mod tests {
         let expected_meta = HotAccountMeta::new()
             .with_lamports(TEST_LAMPORT)
             .with_account_data_padding(padding.len().try_into().unwrap())
-            .with_owner_index(OWNER_INDEX)
+            .with_owner_offset(OwnerOffset(OWNER_OFFSET))
             .with_flags(&flags);
 
         let mut writer = ByteBlockWriter::new(AccountBlockFormat::AlignedRaw);
@@ -449,7 +449,7 @@ pub mod tests {
             .map(|_| {
                 HotAccountMeta::new()
                     .with_lamports(rng.gen_range(0..u64::MAX))
-                    .with_owner_index(rng.gen_range(0..NUM_ACCOUNTS))
+                    .with_owner_offset(OwnerOffset(rng.gen_range(0..NUM_ACCOUNTS)))
             })
             .collect();
 

accounts-db/src/tiered_storage/meta.rs

@@ -1,7 +1,8 @@
 #![allow(dead_code)]
 //! The account meta and related structs for the tiered storage.
 use {
-    crate::accounts_hash::AccountHash, modular_bitfield::prelude::*,
+    crate::{accounts_hash::AccountHash, tiered_storage::owners::OwnerOffset},
+    modular_bitfield::prelude::*,
     solana_sdk::stake_history::Epoch,
 };
 
@@ -31,8 +32,8 @@ pub trait TieredAccountMeta: Sized {
     /// for the account data associated with the current meta.
     fn with_account_data_padding(self, padding: u8) -> Self;
 
-    /// A builder function that initializes the owner's index.
-    fn with_owner_index(self, index: u32) -> Self;
+    /// A builder function that initializes the owner offset.
+    fn with_owner_offset(self, owner_offset: OwnerOffset) -> Self;
 
     /// A builder function that initializes the account data size.
     /// The size here represents the logical data size without compression.
@@ -48,8 +49,8 @@ pub trait TieredAccountMeta: Sized {
     /// Returns the number of padding bytes for the associated account data
     fn account_data_padding(&self) -> u8;
 
-    /// Returns the index to the accounts' owner in the current AccountsFile.
-    fn owner_index(&self) -> u32;
+    /// Returns the offset to the accounts' owner in the current AccountsFile.
+    fn owner_offset(&self) -> OwnerOffset;
 
     /// Returns the AccountMetaFlags of the current meta.
     fn flags(&self) -> &AccountMetaFlags;

accounts-db/src/tiered_storage/owners.rs

@@ -18,7 +18,7 @@ pub struct OwnersBlock;
 ///
 /// Note that as its internal type is u32, it means the maximum number of
 /// unique owners in one TieredStorageFile is 2^32.
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd)]
 pub struct OwnerOffset(pub u32);
 
 /// OwnersBlock is persisted as a consecutive bytes of pubkeys without any