From 4d4b2b99c88bb6c97a7917d7682ec710eb537e99 Mon Sep 17 00:00:00 2001
From: Andrei Vagin <avagin@google.com>
Date: Thu, 19 May 2022 12:05:08 -0700
Subject: [PATCH] tmpfs: use lockdep mutexes

PiperOrigin-RevId: 449803147
---
 pkg/sentry/fsimpl/tmpfs/BUILD        | 34 ++++++++++++++++++++++++++++
 pkg/sentry/fsimpl/tmpfs/directory.go |  3 +--
 pkg/sentry/fsimpl/tmpfs/tmpfs.go     |  7 +++---
 3 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/pkg/sentry/fsimpl/tmpfs/BUILD b/pkg/sentry/fsimpl/tmpfs/BUILD
index 56f9c1e4a..213be2303 100644
--- a/pkg/sentry/fsimpl/tmpfs/BUILD
+++ b/pkg/sentry/fsimpl/tmpfs/BUILD
@@ -1,5 +1,6 @@
 load("//tools:defs.bzl", "go_library", "go_test")
 load("//tools/go_generics:defs.bzl", "go_template_instance")
+load("//pkg/sync/locking:locking.bzl", "declare_mutex", "declare_rwmutex")
 
 licenses(["notice"])
 
@@ -37,6 +38,34 @@ go_template_instance(
     },
 )
 
+declare_mutex(
+    name = "inode_mutex",
+    out = "inode_mutex.go",
+    package = "tmpfs",
+    prefix = "inode",
+)
+
+declare_mutex(
+    name = "pages_used_mutex",
+    out = "pages_used_mutex.go",
+    package = "tmpfs",
+    prefix = "pagesUsed",
+)
+
+declare_mutex(
+    name = "iter_mutex",
+    out = "iter_mutex.go",
+    package = "tmpfs",
+    prefix = "iter",
+)
+
+declare_rwmutex(
+    name = "filesystem_mutex",
+    out = "filesystem_mutex.go",
+    package = "tmpfs",
+    prefix = "filesystem",
+)
+
 go_library(
     name = "tmpfs",
     srcs = [
@@ -44,9 +73,13 @@ go_library(
         "device_file.go",
         "directory.go",
         "filesystem.go",
+        "filesystem_mutex.go",
         "fstree.go",
+        "inode_mutex.go",
         "inode_refs.go",
+        "iter_mutex.go",
         "named_pipe.go",
+        "pages_used_mutex.go",
         "regular_file.go",
         "save_restore.go",
         "socket_file.go",
@@ -82,6 +115,7 @@ go_library(
         "//pkg/sentry/vfs",
         "//pkg/sentry/vfs/memxattr",
         "//pkg/sync",
+        "//pkg/sync/locking",
         "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/fsimpl/tmpfs/directory.go b/pkg/sentry/fsimpl/tmpfs/directory.go
index 7937bb419..49c173970 100644
--- a/pkg/sentry/fsimpl/tmpfs/directory.go
+++ b/pkg/sentry/fsimpl/tmpfs/directory.go
@@ -21,7 +21,6 @@ import (
 	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // +stateify savable
@@ -44,7 +43,7 @@ type directory struct {
 	// (with inode == nil) that represent the iteration position of
 	// directoryFDs. childList is used to support directoryFD.IterDirents()
 	// efficiently. childList is protected by iterMu.
-	iterMu    sync.Mutex `state:"nosave"`
+	iterMu    iterMutex `state:"nosave"`
 	childList dentryList
 }
 
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index 8b988edaf..9ac6d5518 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -45,7 +45,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/sentry/vfs/memxattr"
-	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Name is the default filesystem name.
@@ -81,7 +80,7 @@ type filesystem struct {
 	usage usage.MemoryKind
 
 	// mu serializes changes to the Dentry tree.
-	mu sync.RWMutex `state:"nosave"`
+	mu filesystemRWMutex `state:"nosave"`
 
 	nextInoMinusOne atomicbitops.Uint64 // accessed using atomic memory operations
 
@@ -95,7 +94,7 @@ type filesystem struct {
 
 	// pagesUsed is the pages used out of the tmpfs size.
 	// pagesUsed is protected by pagesUsedMu.
-	pagesUsedMu sync.Mutex `state:"nosave"`
+	pagesUsedMu pagesUsedMutex `state:"nosave"`
 	pagesUsed   uint64
 }
 
@@ -434,7 +433,7 @@ type inode struct {
 
 	// Inode metadata. Writing multiple fields atomically requires holding
 	// mu, othewise atomic operations can be used.
-	mu    sync.Mutex          `state:"nosave"`
+	mu    inodeMutex          `state:"nosave"`
 	mode  atomicbitops.Uint32 // file type and mode
 	nlink atomicbitops.Uint32 // protected by filesystem.mu instead of inode.mu
 	uid   atomicbitops.Uint32 // auth.KUID, but stored as raw uint32 for sync/atomic