buildbarn · EdSchouten · May 13, 2026 · May 13, 2026 · May 13, 2026 · May 13, 2026
diff --git a/MODULE.bazel b/MODULE.bazel
@@ -24,7 +24,7 @@ git_override(
 
 git_override(
     module_name = "com_github_buildbarn_bb_storage",
-    commit = "dc342e1799d72bd927ffc0af1f429e7044118b07",
+    commit = "e5d91cab6de691aa13e549440545fc6f79e87025",
     remote = "https://github.com/buildbarn/bb-storage.git",
 )
 

diff --git a/MODULE.bazel.lock b/MODULE.bazel.lock
diff --git a/go.mod b/go.mod
@@ -16,7 +16,7 @@ require (
 	github.com/bazelbuild/buildtools v0.0.0-20260317083046-eb4b727fa099
 	github.com/bazelbuild/remote-apis v0.0.0-20260216160025-715b73f3f9e4
 	github.com/bazelbuild/rules_go v0.59.0
-	github.com/buildbarn/bb-storage v0.0.0-20260317135248-dc342e1799d7
+	github.com/buildbarn/bb-storage v0.0.0-20260507124548-e5d91cab6de6
 	github.com/buildbarn/go-xdr v0.0.0-20240702182809-236788cf9e89
 	github.com/golang/protobuf v1.5.4
 	github.com/google/uuid v1.6.0

diff --git a/go.sum b/go.sum
@@ -117,8 +117,8 @@ github.com/bazelbuild/rules_go v0.59.0/go.mod h1:Pn30cb4M513fe2rQ6GiJ3q8QyrRsgC7
 github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
-github.com/buildbarn/bb-storage v0.0.0-20260317135248-dc342e1799d7 h1:n6sJ9PxC6WSaLboSi3EcbIxfqgRd7tulb5hiep4kFh4=
-github.com/buildbarn/bb-storage v0.0.0-20260317135248-dc342e1799d7/go.mod h1:96kqnkrdkHHi94Agje3NM8qwrYMxJRSkAqsb7oXRhNI=
+github.com/buildbarn/bb-storage v0.0.0-20260507124548-e5d91cab6de6 h1:h3RPsYigcODS2P1fNErfqPc6WG8I2fuDedYPDtnkGKs=
+github.com/buildbarn/bb-storage v0.0.0-20260507124548-e5d91cab6de6/go.mod h1:LY8xx7Smc8UNMw/wVAbS0gT1HMfrkkag3HMWSWxG7yA=
 github.com/buildbarn/go-sha256tree v0.0.0-20250310211320-0f70f20e855b h1:IKUxixGBm9UxobU7c248z0BF0ojG19uoSLz8MFZM/KA=
 github.com/buildbarn/go-sha256tree v0.0.0-20250310211320-0f70f20e855b/go.mod h1:e7g3/yWApcg+PpDqd4eQEEV8pexQmfCgK3frP+1Wuvk=
 github.com/buildbarn/go-xdr v0.0.0-20240702182809-236788cf9e89 h1:Wtpgk4CIkoEJ7Qx3BwjaMp3TOVv834heqyCC9jMKStM=

diff --git a/pkg/filesystem/virtual/configuration/fuse_mount_enabled.go b/pkg/filesystem/virtual/configuration/fuse_mount_enabled.go
@@ -65,6 +65,9 @@ func (m *fuseMount) Expose(terminationGroup program.Group, rootDirectory virtual
 		// make it into the virtual file system after
 		// calling close()/fsync()/munmap()/msync().
 		EnableWritebackCache: true,
+		// Cap the FUSE asynchronous request queue. When zero,
+		// go-fuse falls back to its default of 12.
+		MaxBackground: int(m.configuration.MaximumBackgroundTasks),
 	}
 
 	switch m.configuration.MountMethod {

diff --git a/pkg/proto/bazeloutputservice/BUILD.bazel b/pkg/proto/bazeloutputservice/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "bazeloutputservice_proto",

diff --git a/pkg/proto/bazeloutputservice/rev2/BUILD.bazel b/pkg/proto/bazeloutputservice/rev2/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "bazeloutputservicerev2_proto",

diff --git a/pkg/proto/buildqueuestate/BUILD.bazel b/pkg/proto/buildqueuestate/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "buildqueuestate_proto",

diff --git a/pkg/proto/cas/BUILD.bazel b/pkg/proto/cas/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "cas_proto",

diff --git a/pkg/proto/completedactionlogger/BUILD.bazel b/pkg/proto/completedactionlogger/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "completedactionlogger_proto",

diff --git a/pkg/proto/configuration/bb_noop_worker/BUILD.bazel b/pkg/proto/configuration/bb_noop_worker/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "bb_noop_worker_proto",

diff --git a/pkg/proto/configuration/bb_runner/BUILD.bazel b/pkg/proto/configuration/bb_runner/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "bb_runner_proto",

diff --git a/pkg/proto/configuration/bb_scheduler/BUILD.bazel b/pkg/proto/configuration/bb_scheduler/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "bb_scheduler_proto",

diff --git a/pkg/proto/configuration/bb_virtual_tmp/BUILD.bazel b/pkg/proto/configuration/bb_virtual_tmp/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "bb_virtual_tmp_proto",

diff --git a/pkg/proto/configuration/bb_worker/BUILD.bazel b/pkg/proto/configuration/bb_worker/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "bb_worker_proto",

diff --git a/pkg/proto/configuration/cas/BUILD.bazel b/pkg/proto/configuration/cas/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "cas_proto",

diff --git a/pkg/proto/configuration/credentials/BUILD.bazel b/pkg/proto/configuration/credentials/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "credentials_proto",

diff --git a/pkg/proto/configuration/filesystem/BUILD.bazel b/pkg/proto/configuration/filesystem/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "filesystem_proto",

diff --git a/pkg/proto/configuration/filesystem/virtual/BUILD.bazel b/pkg/proto/configuration/filesystem/virtual/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "virtual_proto",

diff --git a/pkg/proto/configuration/filesystem/virtual/virtual.pb.go b/pkg/proto/configuration/filesystem/virtual/virtual.pb.go
diff --git a/pkg/proto/configuration/filesystem/virtual/virtual.proto b/pkg/proto/configuration/filesystem/virtual/virtual.proto
@@ -171,6 +171,26 @@ message FUSEMountConfiguration {
 
   // Method to use to create the FUSE mount.
   MountMethod mount_method = 10;
+
+  // The maximum number of asynchronous FUSE requests the kernel is
+  // permitted to have in flight against this mount, corresponding to
+  // the max_background field in the FUSE_INIT reply. The kernel
+  // additionally treats max_background * 3/4 as a congestion threshold;
+  // requests beyond it block in the kernel until the queue drains.
+  //
+  // The go-fuse default of _DEFAULT_BACKGROUND_TASKS (12) is suitable
+  // for bb_clientd and similar low-concurrency consumers. For bb_worker,
+  // where a single mount serves many concurrent actions and each may
+  // issue readahead, the queue saturates quickly and reads stall in
+  // the kernel.
+  //
+  // The appropriate value scales with the number of concurrent worker
+  // threads sharing the mount: more threads means more actions in
+  // flight, each potentially fanning out into many parallel reads.
+  // A reasonable starting point for bb_worker is roughly 128 per
+  // worker thread (e.g. 1024 for 8 threads); tune up if reads still
+  // stall under sustained concurrency.
+  uint32 maximum_background_tasks = 11;
 }
 
 message NFSv4MountConfiguration {

diff --git a/pkg/proto/configuration/scheduler/BUILD.bazel b/pkg/proto/configuration/scheduler/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "scheduler_proto",

diff --git a/pkg/proto/outputpathpersistency/BUILD.bazel b/pkg/proto/outputpathpersistency/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "outputpathpersistency_proto",

diff --git a/pkg/proto/remoteactionrouter/BUILD.bazel b/pkg/proto/remoteactionrouter/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "remoteactionrouter_proto",

diff --git a/pkg/proto/remoteworker/BUILD.bazel b/pkg/proto/remoteworker/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "remoteworker_proto",

diff --git a/pkg/proto/resourceusage/BUILD.bazel b/pkg/proto/resourceusage/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "resourceusage_proto",

diff --git a/pkg/proto/runner/BUILD.bazel b/pkg/proto/runner/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "runner_proto",

diff --git a/pkg/proto/tmp_installer/BUILD.bazel b/pkg/proto/tmp_installer/BUILD.bazel
@@ -1,6 +1,6 @@
+load("@protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_go//go:def.bzl", "go_library")
 load("@rules_go//proto:def.bzl", "go_proto_library")
-load("@rules_proto//proto:defs.bzl", "proto_library")
 
 proto_library(
     name = "tmp_installer_proto",