3 files changed, 10 insertions, 6 deletions
diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go
index a016c896e..51d7368a1 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -640,7 +640,7 @@ func (i *inodeOperations) Allocate(ctx context.Context, inode *fs.Inode, offset,
 
 // WriteOut implements fs.InodeOperations.WriteOut.
 func (i *inodeOperations) WriteOut(ctx context.Context, inode *fs.Inode) error {
-	if !i.session().cachePolicy.cacheUAttrs(inode) {
+	if inode.MountSource.Flags.ReadOnly || !i.session().cachePolicy.cacheUAttrs(inode) {
 		return nil
 	}
 
diff --git a/pkg/sentry/fs/host/inode.go b/pkg/sentry/fs/host/inode.go
index 62f1246aa..fbfba1b58 100644
--- a/pkg/sentry/fs/host/inode.go
+++ b/pkg/sentry/fs/host/inode.go
@@ -368,6 +368,9 @@ func (i *inodeOperations) Allocate(ctx context.Context, inode *fs.Inode, offset,
 
 // WriteOut implements fs.InodeOperations.WriteOut.
 func (i *inodeOperations) WriteOut(ctx context.Context, inode *fs.Inode) error {
+	if inode.MountSource.Flags.ReadOnly {
+		return nil
+	}
 	// Have we been using host kernel metadata caches?
 	if !inode.MountSource.Flags.ForcePageCache || !canMap(inode) {
 		// Then the metadata is already up to date on the host.
diff --git a/pkg/sentry/pgalloc/pgalloc.go b/pkg/sentry/pgalloc/pgalloc.go
index c8d9facc2..46f19d218 100644
--- a/pkg/sentry/pgalloc/pgalloc.go
+++ b/pkg/sentry/pgalloc/pgalloc.go
@@ -393,16 +393,17 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi
 		return platform.FileRange{}, syserror.ENOMEM
 	}
 
-	// Expand the file if needed. Note that findAvailableRange will
-	// appropriately double the fileSize when required.
+	// Expand the file if needed.
 	if int64(fr.End) > f.fileSize {
-		if err := f.file.Truncate(int64(fr.End)); err != nil {
+		// Round the new file size up to be chunk-aligned.
+		newFileSize := (int64(fr.End) + chunkMask) &^ chunkMask
+		if err := f.file.Truncate(newFileSize); err != nil {
 			return platform.FileRange{}, err
 		}
-		f.fileSize = int64(fr.End)
+		f.fileSize = newFileSize
 		f.mappingsMu.Lock()
 		oldMappings := f.mappings.Load().([]uintptr)
-		newMappings := make([]uintptr, f.fileSize>>chunkShift)
+		newMappings := make([]uintptr, newFileSize>>chunkShift)
 		copy(newMappings, oldMappings)
 		f.mappings.Store(newMappings)
 		f.mappingsMu.Unlock()