Fix race condition

src/api/s3_put.rs

@@ -87,17 +87,21 @@ pub async fn handle_put(
 	// that we are uploading something
 	let mut object_version = ObjectVersion {
 		uuid: version_uuid,
-		timestamp: now_msec(),
+		timestamp: version_timestamp,
 		state: ObjectVersionState::Uploading(headers.clone()),
 	};
 	let object = Object::new(bucket.into(), key.into(), vec![object_version.clone()]);
 	garage.object_table.insert(&object).await?;
 
 	// Initialize corresponding entry in version table
+	// Write this entry now, even with empty block list,
+	// to prevent block_ref entries from being deleted (they can be deleted
+	// if the reference a version that isn't found in the version table)
 	let version = Version::new(version_uuid, bucket.into(), key.into(), false);
-	let first_block_hash = blake2sum(&first_block[..]);
+	garage.version_table.insert(&version).await?;
 
 	// Transfer data and verify checksum
+	let first_block_hash = blake2sum(&first_block[..]);
 	let tx_result = read_and_put_blocks(
 		&garage,
 		&version,
@@ -173,7 +177,7 @@ fn ensure_checksum_matches(
 }
 
 async fn read_and_put_blocks(
-	garage: &Arc<Garage>,
+	garage: &Garage,
 	version: &Version,
 	part_number: u64,
 	first_block: Vec<u8>,
@@ -187,7 +191,7 @@ async fn read_and_put_blocks(
 
 	let mut next_offset = first_block.len();
 	let mut put_curr_version_block = put_block_meta(
-		garage.clone(),
+		&garage,
 		&version,
 		part_number,
 		0,
@@ -207,7 +211,7 @@ async fn read_and_put_blocks(
 			let block_hash = blake2sum(&block[..]);
 			let block_len = block.len();
 			put_curr_version_block = put_block_meta(
-				garage.clone(),
+				&garage,
 				&version,
 				part_number,
 				next_offset as u64,
@@ -231,14 +235,13 @@ async fn read_and_put_blocks(
 }
 
 async fn put_block_meta(
-	garage: Arc<Garage>,
+	garage: &Garage,
 	version: &Version,
 	part_number: u64,
 	offset: u64,
 	hash: Hash,
 	size: u64,
 ) -> Result<(), GarageError> {
-	// TODO: don't clone, restart from empty block list ??
 	let mut version = version.clone();
 	version.blocks.put(
 		VersionBlockKey {
@@ -316,6 +319,7 @@ pub async fn handle_create_multipart_upload(
 	let version_uuid = gen_uuid();
 	let headers = get_headers(req)?;
 
+	// Create object in object table
 	let object_version = ObjectVersion {
 		uuid: version_uuid,
 		timestamp: now_msec(),
@@ -324,6 +328,14 @@ pub async fn handle_create_multipart_upload(
 	let object = Object::new(bucket.to_string(), key.to_string(), vec![object_version]);
 	garage.object_table.insert(&object).await?;
 
+	// Insert empty version so that block_ref entries refer to something
+	// (they are inserted concurrently with blocks in the version table, so
+	// there is the possibility that they are inserted before the version table
+	// is created, in which case it is allowed to delete them, e.g. in repair_*)
+	let version = Version::new(version_uuid, bucket.into(), key.into(), false);
+	garage.version_table.insert(&version).await?;
+
+	// Send success response
 	let mut xml = String::new();
 	writeln!(&mut xml, r#"<?xml version="1.0" encoding="UTF-8"?>"#).unwrap();
 	writeln!(
@@ -450,14 +462,12 @@ pub async fn handle_complete_multipart_upload(
 	)?;
 
 	let object = object.ok_or(Error::BadRequest(format!("Object not found")))?;
-	let object_version = object
+	let mut object_version = object
 		.versions()
 		.iter()
-		.find(|v| v.uuid == version_uuid && v.is_uploading());
-	let mut object_version = match object_version {
-		None => return Err(Error::NotFound),
-		Some(x) => x.clone(),
-	};
+		.find(|v| v.uuid == version_uuid && v.is_uploading())
+		.cloned()
+		.ok_or(Error::BadRequest(format!("Version not found")))?;
 
 	let version = version.ok_or(Error::BadRequest(format!("Version not found")))?;
 	if version.blocks.len() == 0 {
@@ -498,12 +508,7 @@ pub async fn handle_complete_multipart_upload(
 	let etag = format!("{}-{}", hex::encode(etag_md5_hasher.finalize()), num_parts);
 
 	// Calculate total size of final object
-	let total_size = version
-		.blocks
-		.items()
-		.iter()
-		.map(|x| x.1.size)
-		.fold(0, |x, y| x + y);
+	let total_size = version.blocks.items().iter().map(|x| x.1.size).sum();
 
 	// Write final object version
 	object_version.state = ObjectVersionState::Complete(ObjectVersionData::FirstBlock(