From 2bc398bfd8fbe38776a512329bd0c40c9c7a5cdf Mon Sep 17 00:00:00 2001
From: Jamie Liu <jamieliu@google.com>
Date: Wed, 17 Jul 2019 15:48:33 -0700
Subject: Separate O_DSYNC and O_SYNC.

PiperOrigin-RevId: 258657913
---
 pkg/sentry/fs/flags.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

(limited to 'pkg/sentry/fs')

diff --git a/pkg/sentry/fs/flags.go b/pkg/sentry/fs/flags.go
index 1278f9c78..0fab876a9 100644
--- a/pkg/sentry/fs/flags.go
+++ b/pkg/sentry/fs/flags.go
@@ -28,7 +28,11 @@ type FileFlags struct {
 	// NonBlocking indicates that I/O should not block.
 	NonBlocking bool
 
-	// Sync indicates that any writes should be synchronous.
+	// DSync indicates that each write will flush data and metadata required to
+	// read the file's contents.
+	DSync bool
+
+	// Sync indicates that each write will flush data and all file metadata.
 	Sync bool
 
 	// Append indicates this file is append only.
@@ -96,6 +100,9 @@ func (f FileFlags) ToLinux() (mask uint) {
 	if f.NonBlocking {
 		mask |= linux.O_NONBLOCK
 	}
+	if f.DSync {
+		mask |= linux.O_DSYNC
+	}
 	if f.Sync {
 		mask |= linux.O_SYNC
 	}
-- 
cgit v1.2.3


From 6f7e2bb388cb29a355dece8921671c0085f53ea9 Mon Sep 17 00:00:00 2001
From: Michael Pratt <mpratt@google.com>
Date: Wed, 17 Jul 2019 16:10:44 -0700
Subject: Take copyMu in Revalidate

copyMu is required to read child.overlay.upper.

PiperOrigin-RevId: 258662209
---
 pkg/sentry/fs/mount_overlay.go | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

(limited to 'pkg/sentry/fs')

diff --git a/pkg/sentry/fs/mount_overlay.go b/pkg/sentry/fs/mount_overlay.go
index 4fcdd6c01..299712cd7 100644
--- a/pkg/sentry/fs/mount_overlay.go
+++ b/pkg/sentry/fs/mount_overlay.go
@@ -66,13 +66,17 @@ func (o *overlayMountSourceOperations) Revalidate(ctx context.Context, name stri
 		panic("an overlay cannot revalidate file objects from the lower fs")
 	}
 
-	// Do we have anything to revalidate?
-	if child.overlay.upper == nil {
-		return false
+	var revalidate bool
+	child.overlay.copyMu.RLock()
+	if child.overlay.upper != nil {
+		// Does the upper require revalidation?
+		revalidate = o.upper.Revalidate(ctx, name, parent.overlay.upper, child.overlay.upper)
+	} else {
+		// Nothing to revalidate.
+		revalidate = false
 	}
-
-	// Does the upper require revalidation?
-	return o.upper.Revalidate(ctx, name, parent.overlay.upper, child.overlay.upper)
+	child.overlay.copyMu.RUnlock()
+	return revalidate
 }
 
 // Keep implements MountSourceOperations by delegating to the upper
-- 
cgit v1.2.3