Pass information about map writableness to filesystems.

This is necessary to implement file seals for memfds.

PiperOrigin-RevId: 225239394
Change-Id: Ib3f1ab31385afc4b24e96cd81a05ef1bebbcbb70

2 files changed, 10 insertions, 10 deletions

diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go
index b0af44ddd..707ca76d2 100644
--- a/pkg/sentry/fs/fsutil/inode_cached.go
+++ b/pkg/sentry/fs/fsutil/inode_cached.go
@@ -686,10 +686,10 @@ func (rw *inodeReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error
 }
 
 // AddMapping implements memmap.Mappable.AddMapping.
-func (c *CachingInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64) error {
+func (c *CachingInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error {
 	// Hot path. Avoid defers.
 	c.mapsMu.Lock()
-	mapped := c.mappings.AddMapping(ms, ar, offset)
+	mapped := c.mappings.AddMapping(ms, ar, offset, writable)
 	// Do this unconditionally since whether we have c.backingFile.FD() >= 0
 	// can change across save/restore.
 	for _, r := range mapped {
@@ -705,10 +705,10 @@ func (c *CachingInodeOperations) AddMapping(ctx context.Context, ms memmap.Mappi
 }
 
 // RemoveMapping implements memmap.Mappable.RemoveMapping.
-func (c *CachingInodeOperations) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64) {
+func (c *CachingInodeOperations) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) {
 	// Hot path. Avoid defers.
 	c.mapsMu.Lock()
-	unmapped := c.mappings.RemoveMapping(ms, ar, offset)
+	unmapped := c.mappings.RemoveMapping(ms, ar, offset, writable)
 	for _, r := range unmapped {
 		c.hostFileMapper.DecRefOn(r)
 	}
@@ -739,8 +739,8 @@ func (c *CachingInodeOperations) RemoveMapping(ctx context.Context, ms memmap.Ma
 }
 
 // CopyMapping implements memmap.Mappable.CopyMapping.
-func (c *CachingInodeOperations) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64) error {
-	return c.AddMapping(ctx, ms, dstAR, offset)
+func (c *CachingInodeOperations) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error {
+	return c.AddMapping(ctx, ms, dstAR, offset, writable)
 }
 
 // Translate implements memmap.Mappable.Translate.
diff --git a/pkg/sentry/fs/fsutil/inode_cached_test.go b/pkg/sentry/fs/fsutil/inode_cached_test.go
index e388ec3d7..ce5201a40 100644
--- a/pkg/sentry/fs/fsutil/inode_cached_test.go
+++ b/pkg/sentry/fs/fsutil/inode_cached_test.go
@@ -305,7 +305,7 @@ func TestRead(t *testing.T) {
 	// be cached.
 	var ms noopMappingSpace
 	ar := usermem.AddrRange{usermem.PageSize, 2 * usermem.PageSize}
-	if err := iops.AddMapping(ctx, ms, ar, usermem.PageSize); err != nil {
+	if err := iops.AddMapping(ctx, ms, ar, usermem.PageSize, true); err != nil {
 		t.Fatalf("AddMapping got %v, want nil", err)
 	}
 	mr := memmap.MappableRange{usermem.PageSize, 2 * usermem.PageSize}
@@ -334,7 +334,7 @@ func TestRead(t *testing.T) {
 
 	// Delete the memory mapping and expect it to cause the cached page to be
 	// uncached.
-	iops.RemoveMapping(ctx, ms, ar, usermem.PageSize)
+	iops.RemoveMapping(ctx, ms, ar, usermem.PageSize, true)
 	if cached := iops.cache.Span(); cached != 0 {
 		t.Fatalf("Span got %d, want 0", cached)
 	}
@@ -363,10 +363,10 @@ func TestWrite(t *testing.T) {
 	// Translate to force them to be cached.
 	var ms noopMappingSpace
 	ar := usermem.AddrRange{usermem.PageSize, 3 * usermem.PageSize}
-	if err := iops.AddMapping(ctx, ms, ar, usermem.PageSize); err != nil {
+	if err := iops.AddMapping(ctx, ms, ar, usermem.PageSize, true); err != nil {
 		t.Fatalf("AddMapping got %v, want nil", err)
 	}
-	defer iops.RemoveMapping(ctx, ms, ar, usermem.PageSize)
+	defer iops.RemoveMapping(ctx, ms, ar, usermem.PageSize, true)
 	mr := memmap.MappableRange{usermem.PageSize, 3 * usermem.PageSize}
 	if _, err := iops.Translate(ctx, mr, mr, usermem.Read); err != nil {
 		t.Fatalf("Translate got %v, want nil", err)