Uses `mmap` for names in tiered storage (#34127)

accounts-db/src/tiered_storage/footer.rs

@@ -204,11 +204,11 @@ impl TieredStorageFooter {
         Ok(footer)
     }
 
-    pub fn new_from_mmap(map: &Mmap) -> TieredStorageResult<&TieredStorageFooter> {
-        let offset = map.len().saturating_sub(FOOTER_TAIL_SIZE);
-        let (footer_size, offset) = get_type::<u64>(map, offset)?;
-        let (_footer_version, offset) = get_type::<u64>(map, offset)?;
-        let (magic_number, _offset) = get_type::<TieredStorageMagicNumber>(map, offset)?;
+    pub fn new_from_mmap(mmap: &Mmap) -> TieredStorageResult<&TieredStorageFooter> {
+        let offset = mmap.len().saturating_sub(FOOTER_TAIL_SIZE);
+        let (footer_size, offset) = get_type::<u64>(mmap, offset)?;
+        let (_footer_version, offset) = get_type::<u64>(mmap, offset)?;
+        let (magic_number, _offset) = get_type::<TieredStorageMagicNumber>(mmap, offset)?;
 
         if *magic_number != TieredStorageMagicNumber::default() {
             return Err(TieredStorageError::MagicNumberMismatch(
@@ -217,8 +217,10 @@ impl TieredStorageFooter {
             ));
         }
 
-        let (footer, _offset) =
-            get_type::<TieredStorageFooter>(map, map.len().saturating_sub(*footer_size as usize))?;
+        let (footer, _offset) = get_type::<TieredStorageFooter>(
+            mmap,
+            mmap.len().saturating_sub(*footer_size as usize),
+        )?;
 
         Ok(footer)
     }

accounts-db/src/tiered_storage/index.rs

@@ -78,7 +78,7 @@ impl IndexBlockFormat {
     /// Returns the address of the account given the specified index.
     pub fn get_account_address<'a>(
         &self,
-        map: &'a Mmap,
+        mmap: &'a Mmap,
         footer: &TieredStorageFooter,
         index_offset: IndexOffset,
     ) -> TieredStorageResult<&'a Pubkey> {
@@ -87,14 +87,14 @@ impl IndexBlockFormat {
                 footer.index_block_offset as usize + std::mem::size_of::<Pubkey>() * index_offset.0
             }
         };
-        let (address, _) = get_type::<Pubkey>(map, account_offset)?;
+        let (address, _) = get_type::<Pubkey>(mmap, account_offset)?;
         Ok(address)
     }
 
     /// Returns the offset to the account given the specified index.
     pub fn get_account_offset(
         &self,
-        map: &Mmap,
+        mmap: &Mmap,
         footer: &TieredStorageFooter,
         index_offset: IndexOffset,
     ) -> TieredStorageResult<AccountOffset> {
@@ -103,7 +103,7 @@ impl IndexBlockFormat {
                 let account_offset = footer.index_block_offset as usize
                     + std::mem::size_of::<Pubkey>() * footer.account_entry_count as usize
                     + index_offset.0 * std::mem::size_of::<u64>();
-                let (account_block_offset, _) = get_type(map, account_offset)?;
+                let (account_block_offset, _) = get_type(mmap, account_offset)?;
                 Ok(AccountOffset {
                     block: *account_block_offset,
                 })
@@ -160,14 +160,14 @@ mod tests {
             .create(false)
             .open(&path)
             .unwrap();
-        let map = unsafe { MmapOptions::new().map(&file).unwrap() };
+        let mmap = unsafe { MmapOptions::new().map(&file).unwrap() };
         for (i, index_entry) in index_entries.iter().enumerate() {
             let account_offset = indexer
-                .get_account_offset(&map, &footer, IndexOffset(i))
+                .get_account_offset(&mmap, &footer, IndexOffset(i))
                 .unwrap();
             assert_eq!(index_entry.block_offset, account_offset.block as u64);
             let address = indexer
-                .get_account_address(&map, &footer, IndexOffset(i))
+                .get_account_address(&mmap, &footer, IndexOffset(i))
                 .unwrap();
             assert_eq!(index_entry.address, address);
         }

accounts-db/src/tiered_storage/mmap_utils.rs

@@ -16,21 +16,21 @@ pub fn get_type<T>(map: &Mmap, offset: usize) -> IoResult<(&T, usize)> {
 /// doesn't overrun the internal buffer. Otherwise return an Error.
 /// Also return the offset of the first byte after the requested data that
 /// falls on a 64-byte boundary.
-pub fn get_slice(map: &Mmap, offset: usize, size: usize) -> IoResult<(&[u8], usize)> {
+pub fn get_slice(mmap: &Mmap, offset: usize, size: usize) -> IoResult<(&[u8], usize)> {
     let (next, overflow) = offset.overflowing_add(size);
-    if overflow || next > map.len() {
+    if overflow || next > mmap.len() {
         error!(
             "Requested offset {} and size {} while mmap only has length {}",
             offset,
             size,
-            map.len()
+            mmap.len()
         );
         return Err(std::io::Error::new(
             std::io::ErrorKind::AddrNotAvailable,
             "Requested offset and data length exceeds the mmap slice",
         ));
     }
-    let data = &map[offset..next];
+    let data = &mmap[offset..next];
     let next = u64_align!(next);
     let ptr = data.as_ptr();