Merge branch 'master' into ip-forwarding

- Merges aleksej-paschenko's with HEAD
- Adds vfs2 support for ip_forward

12 files changed, 187 insertions, 122 deletions

diff --git a/pkg/sentry/fs/fsutil/BUILD b/pkg/sentry/fs/fsutil/BUILD
index b2e8d9c77..5fb419bcd 100644
--- a/pkg/sentry/fs/fsutil/BUILD
+++ b/pkg/sentry/fs/fsutil/BUILD
@@ -1,6 +1,5 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
+load("//tools:defs.bzl", "go_library", "go_test")
 load("//tools/go_generics:defs.bzl", "go_template_instance")
-load("//tools/go_stateify:defs.bzl", "go_library")
 
 package(licenses = ["notice"])
 
@@ -9,7 +8,6 @@ go_template_instance(
     out = "dirty_set_impl.go",
     imports = {
         "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap",
-        "platform": "gvisor.dev/gvisor/pkg/sentry/platform",
     },
     package = "fsutil",
     prefix = "Dirty",
@@ -26,16 +24,16 @@ go_template_instance(
     name = "frame_ref_set_impl",
     out = "frame_ref_set_impl.go",
     imports = {
-        "platform": "gvisor.dev/gvisor/pkg/sentry/platform",
+        "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap",
     },
     package = "fsutil",
-    prefix = "frameRef",
+    prefix = "FrameRef",
     template = "//pkg/segment:generic_set",
     types = {
         "Key": "uint64",
-        "Range": "platform.FileRange",
+        "Range": "memmap.FileRange",
         "Value": "uint64",
-        "Functions": "frameRefSetFunctions",
+        "Functions": "FrameRefSetFunctions",
     },
 )
 
@@ -44,7 +42,6 @@ go_template_instance(
     out = "file_range_set_impl.go",
     imports = {
         "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap",
-        "platform": "gvisor.dev/gvisor/pkg/sentry/platform",
     },
     package = "fsutil",
     prefix = "FileRange",
@@ -53,7 +50,7 @@ go_template_instance(
         "Key": "uint64",
         "Range": "memmap.MappableRange",
         "Value": "uint64",
-        "Functions": "fileRangeSetFunctions",
+        "Functions": "FileRangeSetFunctions",
     },
 )
 
@@ -75,25 +72,24 @@ go_library(
         "inode.go",
         "inode_cached.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/fs/fsutil",
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/abi/linux",
+        "//pkg/context",
         "//pkg/log",
+        "//pkg/safemem",
         "//pkg/sentry/arch",
-        "//pkg/sentry/context",
         "//pkg/sentry/device",
         "//pkg/sentry/fs",
         "//pkg/sentry/kernel/time",
         "//pkg/sentry/memmap",
         "//pkg/sentry/pgalloc",
-        "//pkg/sentry/platform",
-        "//pkg/sentry/safemem",
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sentry/usage",
-        "//pkg/sentry/usermem",
         "//pkg/state",
+        "//pkg/sync",
         "//pkg/syserror",
+        "//pkg/usermem",
         "//pkg/waiter",
     ],
 )
@@ -105,15 +101,15 @@ go_test(
         "dirty_set_test.go",
         "inode_cached_test.go",
     ],
-    embed = [":fsutil"],
+    library = ":fsutil",
     deps = [
-        "//pkg/sentry/context",
-        "//pkg/sentry/context/contexttest",
+        "//pkg/context",
+        "//pkg/safemem",
+        "//pkg/sentry/contexttest",
         "//pkg/sentry/fs",
         "//pkg/sentry/kernel/time",
         "//pkg/sentry/memmap",
-        "//pkg/sentry/safemem",
-        "//pkg/sentry/usermem",
         "//pkg/syserror",
+        "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/fs/fsutil/dirty_set.go b/pkg/sentry/fs/fsutil/dirty_set.go
index 12132680b..2c9446c1d 100644
--- a/pkg/sentry/fs/fsutil/dirty_set.go
+++ b/pkg/sentry/fs/fsutil/dirty_set.go
@@ -17,11 +17,10 @@ package fsutil
 import (
 	"math"
 
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // DirtySet maps offsets into a memmap.Mappable to DirtyInfo. It is used to
@@ -159,7 +158,7 @@ func (ds *DirtySet) AllowClean(mr memmap.MappableRange) {
 // repeatedly until all bytes have been written. max is the true size of the
 // cached object; offsets beyond max will not be passed to writeAt, even if
 // they are marked dirty.
-func SyncDirty(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, dirty *DirtySet, max uint64, mem platform.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error {
+func SyncDirty(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, dirty *DirtySet, max uint64, mem memmap.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error {
 	var changedDirty bool
 	defer func() {
 		if changedDirty {
@@ -194,7 +193,7 @@ func SyncDirty(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet
 // successful partial write, SyncDirtyAll will call it repeatedly until all
 // bytes have been written. max is the true size of the cached object; offsets
 // beyond max will not be passed to writeAt, even if they are marked dirty.
-func SyncDirtyAll(ctx context.Context, cache *FileRangeSet, dirty *DirtySet, max uint64, mem platform.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error {
+func SyncDirtyAll(ctx context.Context, cache *FileRangeSet, dirty *DirtySet, max uint64, mem memmap.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error {
 	dseg := dirty.FirstSegment()
 	for dseg.Ok() {
 		if err := syncDirtyRange(ctx, dseg.Range(), cache, max, mem, writeAt); err != nil {
@@ -210,7 +209,7 @@ func SyncDirtyAll(ctx context.Context, cache *FileRangeSet, dirty *DirtySet, max
 }
 
 // Preconditions: mr must be page-aligned.
-func syncDirtyRange(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, max uint64, mem platform.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error {
+func syncDirtyRange(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, max uint64, mem memmap.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error {
 	for cseg := cache.LowerBoundSegment(mr.Start); cseg.Ok() && cseg.Start() < mr.End; cseg = cseg.NextSegment() {
 		wbr := cseg.Range().Intersect(mr)
 		if max < wbr.Start {
diff --git a/pkg/sentry/fs/fsutil/dirty_set_test.go b/pkg/sentry/fs/fsutil/dirty_set_test.go
index 75575d994..e3579c23c 100644
--- a/pkg/sentry/fs/fsutil/dirty_set_test.go
+++ b/pkg/sentry/fs/fsutil/dirty_set_test.go
@@ -19,7 +19,7 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 func TestDirtySet(t *testing.T) {
diff --git a/pkg/sentry/fs/fsutil/file.go b/pkg/sentry/fs/fsutil/file.go
index fc5b3b1a1..dc9efa5df 100644
--- a/pkg/sentry/fs/fsutil/file.go
+++ b/pkg/sentry/fs/fsutil/file.go
@@ -17,12 +17,12 @@ package fsutil
 import (
 	"io"
 
+	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
-	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
@@ -31,7 +31,7 @@ import (
 type FileNoopRelease struct{}
 
 // Release is a no-op.
-func (FileNoopRelease) Release() {}
+func (FileNoopRelease) Release(context.Context) {}
 
 // SeekWithDirCursor is used to implement fs.FileOperations.Seek.  If dirCursor
 // is not nil and the seek was on a directory, the cursor will be updated.
@@ -296,7 +296,7 @@ func (sdfo *StaticDirFileOperations) IterateDir(ctx context.Context, d *fs.Diren
 func (sdfo *StaticDirFileOperations) Readdir(ctx context.Context, file *fs.File, serializer fs.DentrySerializer) (int64, error) {
 	root := fs.RootFromContext(ctx)
 	if root != nil {
-		defer root.DecRef()
+		defer root.DecRef(ctx)
 	}
 	dirCtx := &fs.DirCtx{
 		Serializer: serializer,
diff --git a/pkg/sentry/fs/fsutil/file_range_set.go b/pkg/sentry/fs/fsutil/file_range_set.go
index 0a5466b0a..bbafebf03 100644
--- a/pkg/sentry/fs/fsutil/file_range_set.go
+++ b/pkg/sentry/fs/fsutil/file_range_set.go
@@ -19,40 +19,39 @@ import (
 	"io"
 	"math"
 
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
-	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // FileRangeSet maps offsets into a memmap.Mappable to offsets into a
-// platform.File. It is used to implement Mappables that store data in
+// memmap.File. It is used to implement Mappables that store data in
 // sparsely-allocated memory.
 //
 // type FileRangeSet <generated by go_generics>
 
-// fileRangeSetFunctions implements segment.Functions for FileRangeSet.
-type fileRangeSetFunctions struct{}
+// FileRangeSetFunctions implements segment.Functions for FileRangeSet.
+type FileRangeSetFunctions struct{}
 
 // MinKey implements segment.Functions.MinKey.
-func (fileRangeSetFunctions) MinKey() uint64 {
+func (FileRangeSetFunctions) MinKey() uint64 {
 	return 0
 }
 
 // MaxKey implements segment.Functions.MaxKey.
-func (fileRangeSetFunctions) MaxKey() uint64 {
+func (FileRangeSetFunctions) MaxKey() uint64 {
 	return math.MaxUint64
 }
 
 // ClearValue implements segment.Functions.ClearValue.
-func (fileRangeSetFunctions) ClearValue(_ *uint64) {
+func (FileRangeSetFunctions) ClearValue(_ *uint64) {
 }
 
 // Merge implements segment.Functions.Merge.
-func (fileRangeSetFunctions) Merge(mr1 memmap.MappableRange, frstart1 uint64, _ memmap.MappableRange, frstart2 uint64) (uint64, bool) {
+func (FileRangeSetFunctions) Merge(mr1 memmap.MappableRange, frstart1 uint64, _ memmap.MappableRange, frstart2 uint64) (uint64, bool) {
 	if frstart1+mr1.Length() != frstart2 {
 		return 0, false
 	}
@@ -60,25 +59,25 @@ func (fileRangeSetFunctions) Merge(mr1 memmap.MappableRange, frstart1 uint64, _
 }
 
 // Split implements segment.Functions.Split.
-func (fileRangeSetFunctions) Split(mr memmap.MappableRange, frstart uint64, split uint64) (uint64, uint64) {
+func (FileRangeSetFunctions) Split(mr memmap.MappableRange, frstart uint64, split uint64) (uint64, uint64) {
 	return frstart, frstart + (split - mr.Start)
 }
 
 // FileRange returns the FileRange mapped by seg.
-func (seg FileRangeIterator) FileRange() platform.FileRange {
+func (seg FileRangeIterator) FileRange() memmap.FileRange {
 	return seg.FileRangeOf(seg.Range())
 }
 
 // FileRangeOf returns the FileRange mapped by mr.
 //
 // Preconditions: seg.Range().IsSupersetOf(mr). mr.Length() != 0.
-func (seg FileRangeIterator) FileRangeOf(mr memmap.MappableRange) platform.FileRange {
+func (seg FileRangeIterator) FileRangeOf(mr memmap.MappableRange) memmap.FileRange {
 	frstart := seg.Value() + (mr.Start - seg.Start())
-	return platform.FileRange{frstart, frstart + mr.Length()}
+	return memmap.FileRange{frstart, frstart + mr.Length()}
 }
 
 // Fill attempts to ensure that all memmap.Mappable offsets in required are
-// mapped to a platform.File offset, by allocating from mf with the given
+// mapped to a memmap.File offset, by allocating from mf with the given
 // memory usage kind and invoking readAt to store data into memory. (If readAt
 // returns a successful partial read, Fill will call it repeatedly until all
 // bytes have been read.) EOF is handled consistently with the requirements of
@@ -141,7 +140,7 @@ func (frs *FileRangeSet) Fill(ctx context.Context, required, optional memmap.Map
 }
 
 // Drop removes segments for memmap.Mappable offsets in mr, freeing the
-// corresponding platform.FileRanges.
+// corresponding memmap.FileRanges.
 //
 // Preconditions: mr must be page-aligned.
 func (frs *FileRangeSet) Drop(mr memmap.MappableRange, mf *pgalloc.MemoryFile) {
@@ -154,7 +153,7 @@ func (frs *FileRangeSet) Drop(mr memmap.MappableRange, mf *pgalloc.MemoryFile) {
 }
 
 // DropAll removes all segments in mr, freeing the corresponding
-// platform.FileRanges.
+// memmap.FileRanges.
 func (frs *FileRangeSet) DropAll(mf *pgalloc.MemoryFile) {
 	for seg := frs.FirstSegment(); seg.Ok(); seg = seg.NextSegment() {
 		mf.DecRef(seg.FileRange())
diff --git a/pkg/sentry/fs/fsutil/frame_ref_set.go b/pkg/sentry/fs/fsutil/frame_ref_set.go
index dd63db32b..a808894df 100644
--- a/pkg/sentry/fs/fsutil/frame_ref_set.go
+++ b/pkg/sentry/fs/fsutil/frame_ref_set.go
@@ -17,27 +17,29 @@ package fsutil
 import (
 	"math"
 
-	"gvisor.dev/gvisor/pkg/sentry/platform"
+	"gvisor.dev/gvisor/pkg/sentry/memmap"
+	"gvisor.dev/gvisor/pkg/sentry/usage"
 )
 
-type frameRefSetFunctions struct{}
+// FrameRefSetFunctions implements segment.Functions for FrameRefSet.
+type FrameRefSetFunctions struct{}
 
 // MinKey implements segment.Functions.MinKey.
-func (frameRefSetFunctions) MinKey() uint64 {
+func (FrameRefSetFunctions) MinKey() uint64 {
 	return 0
 }
 
 // MaxKey implements segment.Functions.MaxKey.
-func (frameRefSetFunctions) MaxKey() uint64 {
+func (FrameRefSetFunctions) MaxKey() uint64 {
 	return math.MaxUint64
 }
 
 // ClearValue implements segment.Functions.ClearValue.
-func (frameRefSetFunctions) ClearValue(val *uint64) {
+func (FrameRefSetFunctions) ClearValue(val *uint64) {
 }
 
 // Merge implements segment.Functions.Merge.
-func (frameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform.FileRange, val2 uint64) (uint64, bool) {
+func (FrameRefSetFunctions) Merge(_ memmap.FileRange, val1 uint64, _ memmap.FileRange, val2 uint64) (uint64, bool) {
 	if val1 != val2 {
 		return 0, false
 	}
@@ -45,6 +47,45 @@ func (frameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform.
 }
 
 // Split implements segment.Functions.Split.
-func (frameRefSetFunctions) Split(_ platform.FileRange, val uint64, _ uint64) (uint64, uint64) {
+func (FrameRefSetFunctions) Split(_ memmap.FileRange, val uint64, _ uint64) (uint64, uint64) {
 	return val, val
 }
+
+// IncRefAndAccount adds a reference on the range fr. All newly inserted segments
+// are accounted as host page cache memory mappings.
+func (refs *FrameRefSet) IncRefAndAccount(fr memmap.FileRange) {
+	seg, gap := refs.Find(fr.Start)
+	for {
+		switch {
+		case seg.Ok() && seg.Start() < fr.End:
+			seg = refs.Isolate(seg, fr)
+			seg.SetValue(seg.Value() + 1)
+			seg, gap = seg.NextNonEmpty()
+		case gap.Ok() && gap.Start() < fr.End:
+			newRange := gap.Range().Intersect(fr)
+			usage.MemoryAccounting.Inc(newRange.Length(), usage.Mapped)
+			seg, gap = refs.InsertWithoutMerging(gap, newRange, 1).NextNonEmpty()
+		default:
+			refs.MergeAdjacent(fr)
+			return
+		}
+	}
+}
+
+// DecRefAndAccount removes a reference on the range fr and untracks segments
+// that are removed from memory accounting.
+func (refs *FrameRefSet) DecRefAndAccount(fr memmap.FileRange) {
+	seg := refs.FindSegment(fr.Start)
+
+	for seg.Ok() && seg.Start() < fr.End {
+		seg = refs.Isolate(seg, fr)
+		if old := seg.Value(); old == 1 {
+			usage.MemoryAccounting.Dec(seg.Range().Length(), usage.Mapped)
+			seg = refs.Remove(seg).NextSegment()
+		} else {
+			seg.SetValue(old - 1)
+			seg = seg.NextSegment()
+		}
+	}
+	refs.MergeAdjacent(fr)
+}
diff --git a/pkg/sentry/fs/fsutil/host_file_mapper.go b/pkg/sentry/fs/fsutil/host_file_mapper.go
index b06a71cc2..ef0113b52 100644
--- a/pkg/sentry/fs/fsutil/host_file_mapper.go
+++ b/pkg/sentry/fs/fsutil/host_file_mapper.go
@@ -16,14 +16,13 @@ package fsutil
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // HostFileMapper caches mappings of an arbitrary host file descriptor. It is
@@ -65,13 +64,18 @@ type mapping struct {
 	writable bool
 }
 
-// NewHostFileMapper returns a HostFileMapper with no references or cached
-// mappings.
+// Init must be called on zero-value HostFileMappers before first use.
+func (f *HostFileMapper) Init() {
+	f.refs = make(map[uint64]int32)
+	f.mappings = make(map[uint64]mapping)
+}
+
+// NewHostFileMapper returns an initialized HostFileMapper allocated on the
+// heap with no references or cached mappings.
 func NewHostFileMapper() *HostFileMapper {
-	return &HostFileMapper{
-		refs:     make(map[uint64]int32),
-		mappings: make(map[uint64]mapping),
-	}
+	f := &HostFileMapper{}
+	f.Init()
+	return f
 }
 
 // IncRefOn increments the reference count on all offsets in mr.
@@ -121,7 +125,7 @@ func (f *HostFileMapper) DecRefOn(mr memmap.MappableRange) {
 // offsets in fr or until the next call to UnmapAll.
 //
 // Preconditions: The caller must hold a reference on all offsets in fr.
-func (f *HostFileMapper) MapInternal(fr platform.FileRange, fd int, write bool) (safemem.BlockSeq, error) {
+func (f *HostFileMapper) MapInternal(fr memmap.FileRange, fd int, write bool) (safemem.BlockSeq, error) {
 	chunks := ((fr.End + chunkMask) >> chunkShift) - (fr.Start >> chunkShift)
 	f.mapsMu.Lock()
 	defer f.mapsMu.Unlock()
@@ -141,7 +145,7 @@ func (f *HostFileMapper) MapInternal(fr platform.FileRange, fd int, write bool)
 }
 
 // Preconditions: f.mapsMu must be locked.
-func (f *HostFileMapper) forEachMappingBlockLocked(fr platform.FileRange, fd int, write bool, fn func(safemem.Block)) error {
+func (f *HostFileMapper) forEachMappingBlockLocked(fr memmap.FileRange, fd int, write bool, fn func(safemem.Block)) error {
 	prot := syscall.PROT_READ
 	if write {
 		prot |= syscall.PROT_WRITE
diff --git a/pkg/sentry/fs/fsutil/host_file_mapper_unsafe.go b/pkg/sentry/fs/fsutil/host_file_mapper_unsafe.go
index ad11a0573..2d4778d64 100644
--- a/pkg/sentry/fs/fsutil/host_file_mapper_unsafe.go
+++ b/pkg/sentry/fs/fsutil/host_file_mapper_unsafe.go
@@ -17,7 +17,7 @@ package fsutil
 import (
 	"unsafe"
 
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
+	"gvisor.dev/gvisor/pkg/safemem"
 )
 
 func (*HostFileMapper) unsafeBlockFromChunkMapping(addr uintptr) safemem.Block {
diff --git a/pkg/sentry/fs/fsutil/host_mappable.go b/pkg/sentry/fs/fsutil/host_mappable.go
index 30475f340..c15d8a946 100644
--- a/pkg/sentry/fs/fsutil/host_mappable.go
+++ b/pkg/sentry/fs/fsutil/host_mappable.go
@@ -16,23 +16,22 @@ package fsutil
 
 import (
 	"math"
-	"sync"
 
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
-// HostMappable implements memmap.Mappable and platform.File over a
+// HostMappable implements memmap.Mappable and memmap.File over a
 // CachedFileObject.
 //
 // Lock order (compare the lock order model in mm/mm.go):
 //   truncateMu ("fs locks")
 //     mu ("memmap.Mappable locks not taken by Translate")
-//       ("platform.File locks")
+//       ("memmap.File locks")
 //   	     backingFile ("CachedFileObject locks")
 //
 // +stateify savable
@@ -124,24 +123,24 @@ func (h *HostMappable) NotifyChangeFD() error {
 	return nil
 }
 
-// MapInternal implements platform.File.MapInternal.
-func (h *HostMappable) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
+// MapInternal implements memmap.File.MapInternal.
+func (h *HostMappable) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
 	return h.hostFileMapper.MapInternal(fr, h.backingFile.FD(), at.Write)
 }
 
-// FD implements platform.File.FD.
+// FD implements memmap.File.FD.
 func (h *HostMappable) FD() int {
 	return h.backingFile.FD()
 }
 
-// IncRef implements platform.File.IncRef.
-func (h *HostMappable) IncRef(fr platform.FileRange) {
+// IncRef implements memmap.File.IncRef.
+func (h *HostMappable) IncRef(fr memmap.FileRange) {
 	mr := memmap.MappableRange{Start: fr.Start, End: fr.End}
 	h.hostFileMapper.IncRefOn(mr)
 }
 
-// DecRef implements platform.File.DecRef.
-func (h *HostMappable) DecRef(fr platform.FileRange) {
+// DecRef implements memmap.File.DecRef.
+func (h *HostMappable) DecRef(fr memmap.FileRange) {
 	mr := memmap.MappableRange{Start: fr.Start, End: fr.End}
 	h.hostFileMapper.DecRefOn(mr)
 }
diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index 4e100a402..1922ff08c 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -15,13 +15,13 @@
 package fsutil
 
 import (
-	"sync"
-
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
@@ -203,7 +203,7 @@ func (i *InodeSimpleAttributes) NotifyModificationAndStatusChange(ctx context.Co
 }
 
 // InodeSimpleExtendedAttributes implements
-// fs.InodeOperations.{Get,Set,List}xattr.
+// fs.InodeOperations.{Get,Set,List}Xattr.
 //
 // +stateify savable
 type InodeSimpleExtendedAttributes struct {
@@ -212,8 +212,8 @@ type InodeSimpleExtendedAttributes struct {
 	xattrs map[string]string
 }
 
-// Getxattr implements fs.InodeOperations.Getxattr.
-func (i *InodeSimpleExtendedAttributes) Getxattr(_ *fs.Inode, name string) (string, error) {
+// GetXattr implements fs.InodeOperations.GetXattr.
+func (i *InodeSimpleExtendedAttributes) GetXattr(_ context.Context, _ *fs.Inode, name string, _ uint64) (string, error) {
 	i.mu.RLock()
 	value, ok := i.xattrs[name]
 	i.mu.RUnlock()
@@ -223,19 +223,31 @@ func (i *InodeSimpleExtendedAttributes) Getxattr(_ *fs.Inode, name string) (stri
 	return value, nil
 }
 
-// Setxattr implements fs.InodeOperations.Setxattr.
-func (i *InodeSimpleExtendedAttributes) Setxattr(_ *fs.Inode, name, value string) error {
+// SetXattr implements fs.InodeOperations.SetXattr.
+func (i *InodeSimpleExtendedAttributes) SetXattr(_ context.Context, _ *fs.Inode, name, value string, flags uint32) error {
 	i.mu.Lock()
+	defer i.mu.Unlock()
 	if i.xattrs == nil {
+		if flags&linux.XATTR_REPLACE != 0 {
+			return syserror.ENODATA
+		}
 		i.xattrs = make(map[string]string)
 	}
+
+	_, ok := i.xattrs[name]
+	if ok && flags&linux.XATTR_CREATE != 0 {
+		return syserror.EEXIST
+	}
+	if !ok && flags&linux.XATTR_REPLACE != 0 {
+		return syserror.ENODATA
+	}
+
 	i.xattrs[name] = value
-	i.mu.Unlock()
 	return nil
 }
 
-// Listxattr implements fs.InodeOperations.Listxattr.
-func (i *InodeSimpleExtendedAttributes) Listxattr(_ *fs.Inode) (map[string]struct{}, error) {
+// ListXattr implements fs.InodeOperations.ListXattr.
+func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) {
 	i.mu.RLock()
 	names := make(map[string]struct{}, len(i.xattrs))
 	for name := range i.xattrs {
@@ -245,6 +257,17 @@ func (i *InodeSimpleExtendedAttributes) Listxattr(_ *fs.Inode) (map[string]struc
 	return names, nil
 }
 
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (i *InodeSimpleExtendedAttributes) RemoveXattr(_ context.Context, _ *fs.Inode, name string) error {
+	i.mu.Lock()
+	defer i.mu.Unlock()
+	if _, ok := i.xattrs[name]; ok {
+		delete(i.xattrs, name)
+		return nil
+	}
+	return syserror.ENOATTR
+}
+
 // staticFile is a file with static contents. It is returned by
 // InodeStaticFileGetter.GetFile.
 //
@@ -437,21 +460,26 @@ func (InodeNotSymlink) Getlink(context.Context, *fs.Inode) (*fs.Dirent, error) {
 // extended attributes.
 type InodeNoExtendedAttributes struct{}
 
-// Getxattr implements fs.InodeOperations.Getxattr.
-func (InodeNoExtendedAttributes) Getxattr(*fs.Inode, string) (string, error) {
+// GetXattr implements fs.InodeOperations.GetXattr.
+func (InodeNoExtendedAttributes) GetXattr(context.Context, *fs.Inode, string, uint64) (string, error) {
 	return "", syserror.EOPNOTSUPP
 }
 
-// Setxattr implements fs.InodeOperations.Setxattr.
-func (InodeNoExtendedAttributes) Setxattr(*fs.Inode, string, string) error {
+// SetXattr implements fs.InodeOperations.SetXattr.
+func (InodeNoExtendedAttributes) SetXattr(context.Context, *fs.Inode, string, string, uint32) error {
 	return syserror.EOPNOTSUPP
 }
 
-// Listxattr implements fs.InodeOperations.Listxattr.
-func (InodeNoExtendedAttributes) Listxattr(*fs.Inode) (map[string]struct{}, error) {
+// ListXattr implements fs.InodeOperations.ListXattr.
+func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) {
 	return nil, syserror.EOPNOTSUPP
 }
 
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (InodeNoExtendedAttributes) RemoveXattr(context.Context, *fs.Inode, string) error {
+	return syserror.EOPNOTSUPP
+}
+
 // InodeNoopRelease implements fs.InodeOperations.Release as a noop.
 type InodeNoopRelease struct{}
 
diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go
index 798920d18..fe8b0b6ac 100644
--- a/pkg/sentry/fs/fsutil/inode_cached.go
+++ b/pkg/sentry/fs/fsutil/inode_cached.go
@@ -17,19 +17,18 @@ package fsutil
 import (
 	"fmt"
 	"io"
-	"sync"
 
+	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/log"
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/time"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
-	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // Lock order (compare the lock order model in mm/mm.go):
@@ -111,7 +110,7 @@ type CachingInodeOperations struct {
 	// refs tracks active references to data in the cache.
 	//
 	// refs is protected by dataMu.
-	refs frameRefSet
+	refs FrameRefSet
 }
 
 // CachingInodeOperationsOptions configures a CachingInodeOperations.
@@ -934,7 +933,7 @@ func maxFillRange(required, optional memmap.MappableRange) memmap.MappableRange
 
 // InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
 func (c *CachingInodeOperations) InvalidateUnsavable(ctx context.Context) error {
-	// Whether we have a host fd (and consequently what platform.File is
+	// Whether we have a host fd (and consequently what memmap.File is
 	// mapped) can change across save/restore, so invalidate all translations
 	// unconditionally.
 	c.mapsMu.Lock()
@@ -999,10 +998,10 @@ func (c *CachingInodeOperations) Evict(ctx context.Context, er pgalloc.Evictable
 	}
 }
 
-// IncRef implements platform.File.IncRef. This is used when we directly map an
-// underlying host fd and CachingInodeOperations is used as the platform.File
+// IncRef implements memmap.File.IncRef. This is used when we directly map an
+// underlying host fd and CachingInodeOperations is used as the memmap.File
 // during translation.
-func (c *CachingInodeOperations) IncRef(fr platform.FileRange) {
+func (c *CachingInodeOperations) IncRef(fr memmap.FileRange) {
 	// Hot path. Avoid defers.
 	c.dataMu.Lock()
 	seg, gap := c.refs.Find(fr.Start)
@@ -1024,10 +1023,10 @@ func (c *CachingInodeOperations) IncRef(fr platform.FileRange) {
 	}
 }
 
-// DecRef implements platform.File.DecRef. This is used when we directly map an
-// underlying host fd and CachingInodeOperations is used as the platform.File
+// DecRef implements memmap.File.DecRef. This is used when we directly map an
+// underlying host fd and CachingInodeOperations is used as the memmap.File
 // during translation.
-func (c *CachingInodeOperations) DecRef(fr platform.FileRange) {
+func (c *CachingInodeOperations) DecRef(fr memmap.FileRange) {
 	// Hot path. Avoid defers.
 	c.dataMu.Lock()
 	seg := c.refs.FindSegment(fr.Start)
@@ -1046,15 +1045,15 @@ func (c *CachingInodeOperations) DecRef(fr platform.FileRange) {
 	c.dataMu.Unlock()
 }
 
-// MapInternal implements platform.File.MapInternal. This is used when we
+// MapInternal implements memmap.File.MapInternal. This is used when we
 // directly map an underlying host fd and CachingInodeOperations is used as the
-// platform.File during translation.
-func (c *CachingInodeOperations) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
+// memmap.File during translation.
+func (c *CachingInodeOperations) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
 	return c.hostFileMapper.MapInternal(fr, c.backingFile.FD(), at.Write)
 }
 
-// FD implements platform.File.FD. This is used when we directly map an
-// underlying host fd and CachingInodeOperations is used as the platform.File
+// FD implements memmap.File.FD. This is used when we directly map an
+// underlying host fd and CachingInodeOperations is used as the memmap.File
 // during translation.
 func (c *CachingInodeOperations) FD() int {
 	return c.backingFile.FD()
diff --git a/pkg/sentry/fs/fsutil/inode_cached_test.go b/pkg/sentry/fs/fsutil/inode_cached_test.go
index 129f314c8..1547584c5 100644
--- a/pkg/sentry/fs/fsutil/inode_cached_test.go
+++ b/pkg/sentry/fs/fsutil/inode_cached_test.go
@@ -19,14 +19,14 @@ import (
 	"io"
 	"testing"
 
-	"gvisor.dev/gvisor/pkg/sentry/context"
-	"gvisor.dev/gvisor/pkg/sentry/context/contexttest"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/safemem"
+	"gvisor.dev/gvisor/pkg/sentry/contexttest"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type noopBackingFile struct{}