refactor: run forget commands in the background

app/server/core/repository-mutex.ts

@@ -49,8 +49,7 @@ class RepositoryMutex {
 	async acquireShared(repositoryId: string, operation: string): Promise<() => void> {
 		const state = this.getOrCreateState(repositoryId);
 
-		const hasExclusiveWaiter = state.waitQueue.some((w) => w.type === "exclusive");
-		if (!state.exclusiveHolder && !hasExclusiveWaiter) {
+		if (!state.exclusiveHolder) {
 			const lockId = this.generateLockId();
 			state.sharedHolders.set(lockId, {
 				id: lockId,
@@ -60,7 +59,9 @@ class RepositoryMutex {
 			return () => this.releaseShared(repositoryId, lockId);
 		}
 
-		logger.debug(`[Mutex] Waiting for shared lock on repo ${repositoryId}: ${operation}`);
+		logger.debug(
+			`[Mutex] Waiting for shared lock on repo ${repositoryId}: ${operation} (exclusive held by: ${state.exclusiveHolder.operation})`,
+		);
 		const lockId = await new Promise<string>((resolve) => {
 			state.waitQueue.push({ type: "shared", operation, resolve });
 		});

app/server/modules/backups/backups.service.ts

@@ -263,12 +263,7 @@ const executeBackup = async (scheduleId: number, manual = false) => {
 		}
 
 		if (schedule.retentionPolicy) {
-			const releaseForgetLock = await repoMutex.acquireExclusive(repository.id, `forget:${volume.name}`);
-			try {
-				await restic.forget(repository.config, schedule.retentionPolicy, { tag: schedule.id.toString() });
-			} finally {
-				releaseForgetLock();
-			}
+			void runForget(schedule.id);
 		}
 
 		const nextBackupAt = calculateNextRun(schedule.cronExpression);
@@ -415,7 +410,7 @@ const runForget = async (scheduleId: number) => {
 		throw new NotFoundError("Repository not found");
 	}
 
-	logger.info(`Manually running retention policy (forget) for schedule ${scheduleId}`);
+	logger.info(`running retention policy (forget) for schedule ${scheduleId}`);
 	const releaseLock = await repoMutex.acquireExclusive(repository.id, `forget:manual:${scheduleId}`);
 	try {
 		await restic.forget(repository.config, schedule.retentionPolicy, { tag: schedule.id.toString() });