Add new error type AccountsFileError (#31631)

#### Problem
AccountsFile- and AppendVec-related code uses io::Error for their main error type.  However, there're many errors under AccountsFile that don't belong to io::Error.

#### Summary of Changes
This PR introduces AccountsFileError and makes minimum changes to keep the PR small.
Subsequent changes related to this will be in separate PRs.

runtime/src/accounts_db.rs

@@ -30,7 +30,7 @@ use {
         },
         accounts_background_service::{DroppedSlotsSender, SendDroppedBankCallback},
         accounts_cache::{AccountsCache, CachedAccount, SlotCache},
-        accounts_file::AccountsFile,
+        accounts_file::{AccountsFile, AccountsFileError},
         accounts_hash::{
             AccountsDeltaHash, AccountsHash, AccountsHashEnum, AccountsHasher,
             CalcAccountsHashConfig, CalculateHashIntermediate, HashStats, IncrementalAccountsHash,
@@ -97,7 +97,7 @@ use {
         boxed::Box,
         collections::{hash_map, BTreeSet, HashMap, HashSet},
         hash::{Hash as StdHash, Hasher as StdHasher},
-        io::{Error as IoError, Result as IoResult},
+        io::Result as IoResult,
         ops::{Range, RangeBounds},
         path::{Path, PathBuf},
         str::FromStr,
@@ -1138,7 +1138,7 @@ impl AccountStorageEntry {
         self.id.load(Ordering::Acquire)
     }
 
-    pub fn flush(&self) -> Result<(), IoError> {
+    pub fn flush(&self) -> Result<(), AccountsFileError> {
         self.accounts.flush()
     }
 

runtime/src/accounts_file.rs

@@ -9,9 +9,10 @@ use {
     solana_sdk::{account::ReadableAccount, clock::Slot, hash::Hash, pubkey::Pubkey},
     std::{
         borrow::Borrow,
-        io, mem,
+        mem,
         path::{Path, PathBuf},
     },
+    thiserror::Error,
 };
 
 // Data placement should be aligned at the next boundary. Without alignment accessing the memory may
@@ -24,6 +25,15 @@ macro_rules! u64_align {
     };
 }
 
+#[derive(Error, Debug)]
+/// An enum for AccountsFile related errors.
+pub enum AccountsFileError {
+    #[error("I/O error: {0}")]
+    Io(#[from] std::io::Error),
+}
+
+pub type Result<T> = std::result::Result<T, AccountsFileError>;
+
 #[derive(Debug)]
 /// An enum for accessing an accounts file which can be implemented
 /// under different formats.
@@ -36,7 +46,7 @@ impl AccountsFile {
     ///
     /// The second element of the returned tuple is the number of accounts in the
     /// accounts file.
-    pub fn new_from_file(path: impl AsRef<Path>, current_len: usize) -> io::Result<(Self, usize)> {
+    pub fn new_from_file(path: impl AsRef<Path>, current_len: usize) -> Result<(Self, usize)> {
         let (av, num_accounts) = AppendVec::new_from_file(path, current_len)?;
         Ok((Self::AppendVec(av), num_accounts))
     }
@@ -50,7 +60,7 @@ impl AccountsFile {
         }
     }
 
-    pub fn flush(&self) -> io::Result<()> {
+    pub fn flush(&self) -> Result<()> {
         match self {
             Self::AppendVec(av) => av.flush(),
         }
@@ -109,7 +119,7 @@ impl AccountsFile {
         &self,
         offset: usize,
         owners: &[&Pubkey],
-    ) -> Result<usize, MatchAccountOwnerError> {
+    ) -> std::result::Result<usize, MatchAccountOwnerError> {
         match self {
             Self::AppendVec(av) => av.account_matches_owners(offset, owners),
         }

runtime/src/append_vec.rs

@@ -10,7 +10,7 @@ use {
             AccountMeta, StorableAccountsWithHashesAndWriteVersions, StoredAccountInfo,
             StoredAccountMeta, StoredMeta, StoredMetaWriteVersion,
         },
-        accounts_file::ALIGN_BOUNDARY_OFFSET,
+        accounts_file::{AccountsFileError, Result, ALIGN_BOUNDARY_OFFSET},
         storable_accounts::StorableAccounts,
         u64_align,
     },
@@ -27,7 +27,7 @@ use {
         borrow::Borrow,
         convert::TryFrom,
         fs::{remove_file, OpenOptions},
-        io::{self, Seek, SeekFrom, Write},
+        io::{Seek, SeekFrom, Write},
         mem,
         path::{Path, PathBuf},
         sync::{
@@ -295,32 +295,33 @@ impl AppendVec {
         self.remove_on_drop = false;
     }
 
-    fn sanitize_len_and_size(current_len: usize, file_size: usize) -> io::Result<()> {
+    fn sanitize_len_and_size(current_len: usize, file_size: usize) -> Result<()> {
         if file_size == 0 {
-            Err(std::io::Error::new(
+            Err(AccountsFileError::Io(std::io::Error::new(
                 std::io::ErrorKind::Other,
                 format!("too small file size {file_size} for AppendVec"),
-            ))
+            )))
         } else if usize::try_from(MAXIMUM_APPEND_VEC_FILE_SIZE)
             .map(|max| file_size > max)
             .unwrap_or(true)
         {
-            Err(std::io::Error::new(
+            Err(AccountsFileError::Io(std::io::Error::new(
                 std::io::ErrorKind::Other,
                 format!("too large file size {file_size} for AppendVec"),
-            ))
+            )))
         } else if current_len > file_size {
-            Err(std::io::Error::new(
+            Err(AccountsFileError::Io(std::io::Error::new(
                 std::io::ErrorKind::Other,
                 format!("current_len is larger than file size ({file_size})"),
-            ))
+            )))
         } else {
             Ok(())
         }
     }
 
-    pub fn flush(&self) -> io::Result<()> {
-        self.map.flush()
+    pub fn flush(&self) -> Result<()> {
+        self.map.flush()?;
+        Ok(())
     }
 
     pub fn reset(&self) {
@@ -351,7 +352,7 @@ impl AppendVec {
         format!("{slot}.{id}")
     }
 
-    pub fn new_from_file<P: AsRef<Path>>(path: P, current_len: usize) -> io::Result<(Self, usize)> {
+    pub fn new_from_file<P: AsRef<Path>>(path: P, current_len: usize) -> Result<(Self, usize)> {
         let new = Self::new_from_file_unchecked(&path, current_len)?;
 
         let (sanitized, num_accounts) = new.sanitize_layout_and_length();
@@ -362,17 +363,17 @@ impl AppendVec {
                 "incorrect layout/length/data in the appendvec at path {}",
                 path.as_ref().display()
             );
-            return Err(std::io::Error::new(std::io::ErrorKind::Other, err_msg));
+            return Err(AccountsFileError::Io(std::io::Error::new(
+                std::io::ErrorKind::Other,
+                err_msg,
+            )));
         }
 
         Ok((new, num_accounts))
     }
 
     /// Creates an appendvec from file without performing sanitize checks or counting the number of accounts
-    pub fn new_from_file_unchecked<P: AsRef<Path>>(
-        path: P,
-        current_len: usize,
-    ) -> io::Result<Self> {
+    pub fn new_from_file_unchecked<P: AsRef<Path>>(path: P, current_len: usize) -> Result<Self> {
         let file_size = std::fs::metadata(&path)?.len();
         Self::sanitize_len_and_size(current_len, file_size as usize)?;
 
@@ -531,7 +532,7 @@ impl AppendVec {
         &self,
         offset: usize,
         owners: &[&Pubkey],
-    ) -> Result<usize, MatchAccountOwnerError> {
+    ) -> std::result::Result<usize, MatchAccountOwnerError> {
         let account_meta = self
             .get_account_meta(offset)
             .ok_or(MatchAccountOwnerError::UnableToLoad)?;
@@ -937,7 +938,7 @@ pub mod tests {
             .expect("create a test file for mmap");
 
         let result = AppendVec::new_from_file(path, 0);
-        assert_matches!(result, Err(ref message) if message.to_string() == *"too small file size 0 for AppendVec");
+        assert_matches!(result, Err(ref message) if message.to_string().contains("too small file size 0 for AppendVec"));
     }
 
     #[test]
@@ -945,7 +946,7 @@ pub mod tests {
         const LEN: usize = 0;
         const SIZE: usize = 0;
         let result = AppendVec::sanitize_len_and_size(LEN, SIZE);
-        assert_matches!(result, Err(ref message) if message.to_string() == *"too small file size 0 for AppendVec");
+        assert_matches!(result, Err(ref message) if message.to_string().contains("too small file size 0 for AppendVec"));
     }
 
     #[test]
@@ -961,7 +962,7 @@ pub mod tests {
         const LEN: usize = 0;
         const SIZE: usize = 16 * 1024 * 1024 * 1024 + 1;
         let result = AppendVec::sanitize_len_and_size(LEN, SIZE);
-        assert_matches!(result, Err(ref message) if message.to_string() == *"too large file size 17179869185 for AppendVec");
+        assert_matches!(result, Err(ref message) if message.to_string().contains("too large file size 17179869185 for AppendVec"));
     }
 
     #[test]
@@ -977,7 +978,7 @@ pub mod tests {
         const LEN: usize = 1024 * 1024 + 1;
         const SIZE: usize = 1024 * 1024;
         let result = AppendVec::sanitize_len_and_size(LEN, SIZE);
-        assert_matches!(result, Err(ref message) if message.to_string() == *"current_len is larger than file size (1048576)");
+        assert_matches!(result, Err(ref message) if message.to_string().contains("current_len is larger than file size (1048576)"));
     }
 
     #[test]
@@ -1165,7 +1166,7 @@ pub mod tests {
         }
 
         let result = AppendVec::new_from_file(path, accounts_len);
-        assert_matches!(result, Err(ref message) if message.to_string().starts_with("incorrect layout/length/data"));
+        assert_matches!(result, Err(ref message) if message.to_string().contains("incorrect layout/length/data"));
     }
 
     #[test]
@@ -1193,7 +1194,7 @@ pub mod tests {
         let accounts_len = av.len();
         drop(av);
         let result = AppendVec::new_from_file(path, accounts_len);
-        assert_matches!(result, Err(ref message) if message.to_string().starts_with("incorrect layout/length/data"));
+        assert_matches!(result, Err(ref message) if message.to_string().contains("incorrect layout/length/data"));
     }
 
     #[test]
@@ -1219,7 +1220,7 @@ pub mod tests {
         let accounts_len = av.len();
         drop(av);
         let result = AppendVec::new_from_file(path, accounts_len);
-        assert_matches!(result, Err(ref message) if message.to_string().starts_with("incorrect layout/length/data"));
+        assert_matches!(result, Err(ref message) if message.to_string().contains("incorrect layout/length/data"));
     }
 
     #[test]
@@ -1281,7 +1282,7 @@ pub mod tests {
         let accounts_len = av.len();
         drop(av);
         let result = AppendVec::new_from_file(path, accounts_len);
-        assert_matches!(result, Err(ref message) if message.to_string().starts_with("incorrect layout/length/data"));
+        assert_matches!(result, Err(ref message) if message.to_string().contains("incorrect layout/length/data"));
     }
 
     #[test]

runtime/src/serde_snapshot.rs

@@ -627,7 +627,9 @@ pub(crate) fn reconstruct_single_storage(
     current_len: usize,
     append_vec_id: AppendVecId,
 ) -> io::Result<Arc<AccountStorageEntry>> {
-    let (accounts_file, num_accounts) = AccountsFile::new_from_file(append_vec_path, current_len)?;
+    let (accounts_file, num_accounts) =
+        AccountsFile::new_from_file(append_vec_path, current_len)
+            .map_err(|err| io::Error::new(io::ErrorKind::Other, format!("{}", err)))?;
     Ok(Arc::new(AccountStorageEntry::new_existing(
         *slot,
         append_vec_id,

runtime/src/serde_snapshot/tests.rs

@@ -8,7 +8,7 @@ use {
         accounts_db::{
             get_temp_accounts_paths, test_utils::create_test_accounts, AccountShrinkThreshold,
         },
-        accounts_file::AccountsFile,
+        accounts_file::{AccountsFile, AccountsFileError},
         accounts_hash::{AccountsDeltaHash, AccountsHash},
         bank::{Bank, BankTestConfig},
         epoch_accounts_hash,
@@ -43,7 +43,7 @@ use {
 fn copy_append_vecs<P: AsRef<Path>>(
     accounts_db: &AccountsDb,
     output_dir: P,
-) -> std::io::Result<StorageAndNextAppendVecId> {
+) -> Result<StorageAndNextAppendVecId, AccountsFileError> {
     let storage_entries = accounts_db.get_snapshot_storages(RangeFull).0;
     let storage: AccountStorageMap = AccountStorageMap::with_capacity(storage_entries.len());
     let mut next_append_vec_id = 0;

runtime/src/snapshot_utils.rs

@@ -5,6 +5,7 @@ use {
             AccountShrinkThreshold, AccountStorageEntry, AccountsDbConfig, AtomicAppendVecId,
             CalcAccountsHashDataSource,
         },
+        accounts_file::AccountsFileError,
         accounts_hash::AccountsHash,
         accounts_index::AccountSecondaryIndexes,
         accounts_update_notifier_interface::AccountsUpdateNotifier,
@@ -308,6 +309,9 @@ pub enum SnapshotError {
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
+    #[error("AccountsFile error: {0}")]
+    AccountsFileError(#[from] AccountsFileError),
+
     #[error("serialization error: {0}")]
     Serialize(#[from] bincode::Error),