Merge release-20200518.0-45-g0bc022b7 (automated)

77 files changed, 262 insertions, 134 deletions

diff --git a/pkg/sentry/fsimpl/devpts/devpts.go b/pkg/sentry/fsimpl/devpts/devpts.go
index c03c65445..c03c65445 100755..100644
--- a/pkg/sentry/fsimpl/devpts/devpts.go
+++ b/pkg/sentry/fsimpl/devpts/devpts.go
diff --git a/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go b/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go
index 90cd7937c..90cd7937c 100755..100644
--- a/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go
+++ b/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go
diff --git a/pkg/sentry/fsimpl/devpts/line_discipline.go b/pkg/sentry/fsimpl/devpts/line_discipline.go
index f7bc325d1..f7bc325d1 100755..100644
--- a/pkg/sentry/fsimpl/devpts/line_discipline.go
+++ b/pkg/sentry/fsimpl/devpts/line_discipline.go
diff --git a/pkg/sentry/fsimpl/devpts/master.go b/pkg/sentry/fsimpl/devpts/master.go
index 7a7ce5d81..7a7ce5d81 100755..100644
--- a/pkg/sentry/fsimpl/devpts/master.go
+++ b/pkg/sentry/fsimpl/devpts/master.go
diff --git a/pkg/sentry/fsimpl/devpts/queue.go b/pkg/sentry/fsimpl/devpts/queue.go
index dffb4232c..dffb4232c 100755..100644
--- a/pkg/sentry/fsimpl/devpts/queue.go
+++ b/pkg/sentry/fsimpl/devpts/queue.go
diff --git a/pkg/sentry/fsimpl/devpts/slave.go b/pkg/sentry/fsimpl/devpts/slave.go
index 526cd406c..526cd406c 100755..100644
--- a/pkg/sentry/fsimpl/devpts/slave.go
+++ b/pkg/sentry/fsimpl/devpts/slave.go
diff --git a/pkg/sentry/fsimpl/devpts/terminal.go b/pkg/sentry/fsimpl/devpts/terminal.go
index 7d2781c54..7d2781c54 100755..100644
--- a/pkg/sentry/fsimpl/devpts/terminal.go
+++ b/pkg/sentry/fsimpl/devpts/terminal.go
diff --git a/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go b/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go
index 142ee53b0..142ee53b0 100755..100644
--- a/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go
+++ b/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go
diff --git a/pkg/sentry/fsimpl/devtmpfs/devtmpfs_state_autogen.go b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_state_autogen.go
index ac054eb77..ac054eb77 100755..100644
--- a/pkg/sentry/fsimpl/devtmpfs/devtmpfs_state_autogen.go
+++ b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_state_autogen.go
diff --git a/pkg/sentry/fsimpl/eventfd/eventfd.go b/pkg/sentry/fsimpl/eventfd/eventfd.go
index c573d7935..c573d7935 100755..100644
--- a/pkg/sentry/fsimpl/eventfd/eventfd.go
+++ b/pkg/sentry/fsimpl/eventfd/eventfd.go
diff --git a/pkg/sentry/fsimpl/eventfd/eventfd_state_autogen.go b/pkg/sentry/fsimpl/eventfd/eventfd_state_autogen.go
index e83f6aed8..e83f6aed8 100755..100644
--- a/pkg/sentry/fsimpl/eventfd/eventfd_state_autogen.go
+++ b/pkg/sentry/fsimpl/eventfd/eventfd_state_autogen.go
diff --git a/pkg/sentry/fsimpl/gofer/dentry_list.go b/pkg/sentry/fsimpl/gofer/dentry_list.go
index fa03e2501..fa03e2501 100755..100644
--- a/pkg/sentry/fsimpl/gofer/dentry_list.go
+++ b/pkg/sentry/fsimpl/gofer/dentry_list.go
diff --git a/pkg/sentry/fsimpl/gofer/directory.go b/pkg/sentry/fsimpl/gofer/directory.go
index b98218753..b98218753 100755..100644
--- a/pkg/sentry/fsimpl/gofer/directory.go
+++ b/pkg/sentry/fsimpl/gofer/directory.go
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
index 7f2181216..7f2181216 100755..100644
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ b/pkg/sentry/fsimpl/gofer/filesystem.go
diff --git a/pkg/sentry/fsimpl/gofer/fstree.go b/pkg/sentry/fsimpl/gofer/fstree.go
index 9ef0dd8c8..9ef0dd8c8 100755..100644
--- a/pkg/sentry/fsimpl/gofer/fstree.go
+++ b/pkg/sentry/fsimpl/gofer/fstree.go
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index ebf063a58..131da332f 100755..100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -84,12 +84,6 @@ type filesystem struct {
 	// devMinor is the filesystem's minor device number. devMinor is immutable.
 	devMinor uint32
 
-	// uid and gid are the effective KUID and KGID of the filesystem's creator,
-	// and are used as the owner and group for files that don't specify one.
-	// uid and gid are immutable.
-	uid auth.KUID
-	gid auth.KGID
-
 	// renameMu serves two purposes:
 	//
 	// - It synchronizes path resolution with renaming initiated by this
@@ -122,6 +116,8 @@ type filesystemOptions struct {
 	fd      int
 	aname   string
 	interop InteropMode // derived from the "cache" mount option
+	dfltuid auth.KUID
+	dfltgid auth.KGID
 	msize   uint32
 	version string
 
@@ -230,6 +226,15 @@ type InternalFilesystemOptions struct {
 	OpenSocketsByConnecting bool
 }
 
+// _V9FS_DEFUID and _V9FS_DEFGID (from Linux's fs/9p/v9fs.h) are the default
+// UIDs and GIDs used for files that do not provide a specific owner or group
+// respectively.
+const (
+	// uint32(-2) doesn't work in Go.
+	_V9FS_DEFUID = auth.KUID(4294967294)
+	_V9FS_DEFGID = auth.KGID(4294967294)
+)
+
 // Name implements vfs.FilesystemType.Name.
 func (FilesystemType) Name() string {
 	return Name
@@ -315,6 +320,31 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 		}
 	}
 
+	// Parse the default UID and GID.
+	fsopts.dfltuid = _V9FS_DEFUID
+	if dfltuidstr, ok := mopts["dfltuid"]; ok {
+		delete(mopts, "dfltuid")
+		dfltuid, err := strconv.ParseUint(dfltuidstr, 10, 32)
+		if err != nil {
+			ctx.Warningf("gofer.FilesystemType.GetFilesystem: invalid default UID: dfltuid=%s", dfltuidstr)
+			return nil, nil, syserror.EINVAL
+		}
+		// In Linux, dfltuid is interpreted as a UID and is converted to a KUID
+		// in the caller's user namespace, but goferfs isn't
+		// application-mountable.
+		fsopts.dfltuid = auth.KUID(dfltuid)
+	}
+	fsopts.dfltgid = _V9FS_DEFGID
+	if dfltgidstr, ok := mopts["dfltgid"]; ok {
+		delete(mopts, "dfltgid")
+		dfltgid, err := strconv.ParseUint(dfltgidstr, 10, 32)
+		if err != nil {
+			ctx.Warningf("gofer.FilesystemType.GetFilesystem: invalid default UID: dfltgid=%s", dfltgidstr)
+			return nil, nil, syserror.EINVAL
+		}
+		fsopts.dfltgid = auth.KGID(dfltgid)
+	}
+
 	// Parse the 9P message size.
 	fsopts.msize = 1024 * 1024 // 1M, tested to give good enough performance up to 64M
 	if msizestr, ok := mopts["msize"]; ok {
@@ -422,8 +452,6 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 		client:           client,
 		clock:            ktime.RealtimeClockFromContext(ctx),
 		devMinor:         devMinor,
-		uid:              creds.EffectiveKUID,
-		gid:              creds.EffectiveKGID,
 		syncableDentries: make(map[*dentry]struct{}),
 		specialFileFDs:   make(map[*specialFileFD]struct{}),
 	}
@@ -672,8 +700,8 @@ func (fs *filesystem) newDentry(ctx context.Context, file p9file, qid p9.QID, ma
 		file:      file,
 		ino:       qid.Path,
 		mode:      uint32(attr.Mode),
-		uid:       uint32(fs.uid),
-		gid:       uint32(fs.gid),
+		uid:       uint32(fs.opts.dfltuid),
+		gid:       uint32(fs.opts.dfltgid),
 		blockSize: usermem.PageSize,
 		handle: handle{
 			fd: -1,
@@ -928,8 +956,8 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin
 		// so we can't race with Write or another truncate.)
 		d.dataMu.Unlock()
 		if d.size < oldSize {
-			oldpgend := pageRoundUp(oldSize)
-			newpgend := pageRoundUp(d.size)
+			oldpgend, _ := usermem.PageRoundUp(oldSize)
+			newpgend, _ := usermem.PageRoundUp(d.size)
 			if oldpgend != newpgend {
 				d.mapsMu.Lock()
 				d.mappings.Invalidate(memmap.MappableRange{newpgend, oldpgend}, memmap.InvalidateOpts{
diff --git a/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
index 546d432c9..546d432c9 100755..100644
--- a/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
+++ b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
diff --git a/pkg/sentry/fsimpl/gofer/handle.go b/pkg/sentry/fsimpl/gofer/handle.go
index 724a3f1f7..724a3f1f7 100755..100644
--- a/pkg/sentry/fsimpl/gofer/handle.go
+++ b/pkg/sentry/fsimpl/gofer/handle.go
diff --git a/pkg/sentry/fsimpl/gofer/p9file.go b/pkg/sentry/fsimpl/gofer/p9file.go
index 87f0b877f..87f0b877f 100755..100644
--- a/pkg/sentry/fsimpl/gofer/p9file.go
+++ b/pkg/sentry/fsimpl/gofer/p9file.go
diff --git a/pkg/sentry/fsimpl/gofer/pagemath.go b/pkg/sentry/fsimpl/gofer/pagemath.go
deleted file mode 100755
index 847cb0784..000000000
--- a/pkg/sentry/fsimpl/gofer/pagemath.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package gofer
-
-import (
-	"gvisor.dev/gvisor/pkg/usermem"
-)
-
-// This are equivalent to usermem.Addr.RoundDown/Up, but without the
-// potentially truncating conversion to usermem.Addr. This is necessary because
-// there is no way to define generic "PageRoundDown/Up" functions in Go.
-
-func pageRoundDown(x uint64) uint64 {
-	return x &^ (usermem.PageSize - 1)
-}
-
-func pageRoundUp(x uint64) uint64 {
-	return pageRoundDown(x + usermem.PageSize - 1)
-}
diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go
index 857f7c74e..0d10cf7ac 100755..100644
--- a/pkg/sentry/fsimpl/gofer/regular_file.go
+++ b/pkg/sentry/fsimpl/gofer/regular_file.go
@@ -148,9 +148,9 @@ func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
 			return 0, err
 		}
 		// Remove touched pages from the cache.
-		pgstart := pageRoundDown(uint64(offset))
-		pgend := pageRoundUp(uint64(offset + src.NumBytes()))
-		if pgend < pgstart {
+		pgstart := usermem.PageRoundDown(uint64(offset))
+		pgend, ok := usermem.PageRoundUp(uint64(offset + src.NumBytes()))
+		if !ok {
 			return 0, syserror.EINVAL
 		}
 		mr := memmap.MappableRange{pgstart, pgend}
@@ -306,9 +306,10 @@ func (rw *dentryReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error)
 			if fillCache {
 				// Read into the cache, then re-enter the loop to read from the
 				// cache.
+				gapEnd, _ := usermem.PageRoundUp(gapMR.End)
 				reqMR := memmap.MappableRange{
-					Start: pageRoundDown(gapMR.Start),
-					End:   pageRoundUp(gapMR.End),
+					Start: usermem.PageRoundDown(gapMR.Start),
+					End:   gapEnd,
 				}
 				optMR := gap.Range()
 				err := rw.d.cache.Fill(rw.ctx, reqMR, maxFillRange(reqMR, optMR), mf, usage.PageCache, rw.d.handle.readToBlocksAt)
@@ -671,7 +672,7 @@ func (d *dentry) Translate(ctx context.Context, required, optional memmap.Mappab
 
 	// Constrain translations to d.size (rounded up) to prevent translation to
 	// pages that may be concurrently truncated.
-	pgend := pageRoundUp(d.size)
+	pgend, _ := usermem.PageRoundUp(d.size)
 	var beyondEOF bool
 	if required.End > pgend {
 		if required.Start >= pgend {
@@ -818,43 +819,15 @@ type dentryPlatformFile struct {
 // IncRef implements platform.File.IncRef.
 func (d *dentryPlatformFile) IncRef(fr platform.FileRange) {
 	d.dataMu.Lock()
-	seg, gap := d.fdRefs.Find(fr.Start)
-	for {
-		switch {
-		case seg.Ok() && seg.Start() < fr.End:
-			seg = d.fdRefs.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 = d.fdRefs.InsertWithoutMerging(gap, newRange, 1).NextNonEmpty()
-		default:
-			d.fdRefs.MergeAdjacent(fr)
-			d.dataMu.Unlock()
-			return
-		}
-	}
+	d.fdRefs.IncRefAndAccount(fr)
+	d.dataMu.Unlock()
 }
 
 // DecRef implements platform.File.DecRef.
 func (d *dentryPlatformFile) DecRef(fr platform.FileRange) {
 	d.dataMu.Lock()
-	seg := d.fdRefs.FindSegment(fr.Start)
-
-	for seg.Ok() && seg.Start() < fr.End {
-		seg = d.fdRefs.Isolate(seg, fr)
-		if old := seg.Value(); old == 1 {
-			usage.MemoryAccounting.Dec(seg.Range().Length(), usage.Mapped)
-			seg = d.fdRefs.Remove(seg).NextSegment()
-		} else {
-			seg.SetValue(old - 1)
-			seg = seg.NextSegment()
-		}
-	}
-	d.fdRefs.MergeAdjacent(fr)
+	d.fdRefs.DecRefAndAccount(fr)
 	d.dataMu.Unlock()
-
 }
 
 // MapInternal implements platform.File.MapInternal.
diff --git a/pkg/sentry/fsimpl/gofer/socket.go b/pkg/sentry/fsimpl/gofer/socket.go
index d6dbe9092..d6dbe9092 100755..100644
--- a/pkg/sentry/fsimpl/gofer/socket.go
+++ b/pkg/sentry/fsimpl/gofer/socket.go
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go
index a464e6a94..a464e6a94 100755..100644
--- a/pkg/sentry/fsimpl/gofer/special_file.go
+++ b/pkg/sentry/fsimpl/gofer/special_file.go
diff --git a/pkg/sentry/fsimpl/gofer/symlink.go b/pkg/sentry/fsimpl/gofer/symlink.go
index 2ec819f86..2ec819f86 100755..100644
--- a/pkg/sentry/fsimpl/gofer/symlink.go
+++ b/pkg/sentry/fsimpl/gofer/symlink.go
diff --git a/pkg/sentry/fsimpl/gofer/time.go b/pkg/sentry/fsimpl/gofer/time.go
index 2608e7e1d..2608e7e1d 100755..100644
--- a/pkg/sentry/fsimpl/gofer/time.go
+++ b/pkg/sentry/fsimpl/gofer/time.go
diff --git a/pkg/sentry/fsimpl/host/control.go b/pkg/sentry/fsimpl/host/control.go
index b9082a20f..b9082a20f 100755..100644
--- a/pkg/sentry/fsimpl/host/control.go
+++ b/pkg/sentry/fsimpl/host/control.go
diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index 8caf55a1b..18b127521 100755..100644
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -86,15 +86,13 @@ func NewFD(ctx context.Context, mnt *vfs.Mount, hostFD int, opts *NewFDOptions)
 
 	i := &inode{
 		hostFD:     hostFD,
-		seekable:   seekable,
+		ino:        fs.NextIno(),
 		isTTY:      opts.IsTTY,
-		canMap:     canMap(uint32(fileType)),
 		wouldBlock: wouldBlock(uint32(fileType)),
-		ino:        fs.NextIno(),
-		// For simplicity, set offset to 0. Technically, we should use the existing
-		// offset on the host if the file is seekable.
-		offset: 0,
+		seekable:   seekable,
+		canMap:     canMap(uint32(fileType)),
 	}
+	i.pf.inode = i
 
 	// Non-seekable files can't be memory mapped, assert this.
 	if !i.seekable && i.canMap {
@@ -117,6 +115,10 @@ func NewFD(ctx context.Context, mnt *vfs.Mount, hostFD int, opts *NewFDOptions)
 
 	// i.open will take a reference on d.
 	defer d.DecRef()
+
+	// For simplicity, fileDescription.offset is set to 0. Technically, we
+	// should only set to 0 on files that are not seekable (sockets, pipes,
+	// etc.), and use the offset from the host fd otherwise when importing.
 	return i.open(ctx, d.VFSDentry(), mnt, flags)
 }
 
@@ -189,11 +191,15 @@ type inode struct {
 	// This field is initialized at creation time and is immutable.
 	hostFD int
 
-	// wouldBlock is true if the host FD would return EWOULDBLOCK for
-	// operations that would block.
+	// ino is an inode number unique within this filesystem.
 	//
 	// This field is initialized at creation time and is immutable.
-	wouldBlock bool
+	ino uint64
+
+	// isTTY is true if this file represents a TTY.
+	//
+	// This field is initialized at creation time and is immutable.
+	isTTY bool
 
 	// seekable is false if the host fd points to a file representing a stream,
 	// e.g. a socket or a pipe. Such files are not seekable and can return
@@ -202,29 +208,29 @@ type inode struct {
 	// This field is initialized at creation time and is immutable.
 	seekable bool
 
-	// isTTY is true if this file represents a TTY.
+	// wouldBlock is true if the host FD would return EWOULDBLOCK for
+	// operations that would block.
 	//
 	// This field is initialized at creation time and is immutable.
-	isTTY bool
+	wouldBlock bool
+
+	// Event queue for blocking operations.
+	queue waiter.Queue
 
 	// canMap specifies whether we allow the file to be memory mapped.
 	//
 	// This field is initialized at creation time and is immutable.
 	canMap bool
 
-	// ino is an inode number unique within this filesystem.
-	//
-	// This field is initialized at creation time and is immutable.
-	ino uint64
+	// mapsMu protects mappings.
+	mapsMu sync.Mutex
 
-	// offsetMu protects offset.
-	offsetMu sync.Mutex
-
-	// offset specifies the current file offset.
-	offset int64
+	// If canMap is true, mappings tracks mappings of hostFD into
+	// memmap.MappingSpaces.
+	mappings memmap.MappingSet
 
-	// Event queue for blocking operations.
-	queue waiter.Queue
+	// pf implements platform.File for mappings of hostFD.
+	pf inodePlatformFile
 }
 
 // CheckPermissions implements kernfs.Inode.
@@ -388,6 +394,21 @@ func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Cre
 		if err := syscall.Ftruncate(i.hostFD, int64(s.Size)); err != nil {
 			return err
 		}
+		oldSize := uint64(hostStat.Size)
+		if s.Size < oldSize {
+			oldpgend, _ := usermem.PageRoundUp(oldSize)
+			newpgend, _ := usermem.PageRoundUp(s.Size)
+			if oldpgend != newpgend {
+				i.mapsMu.Lock()
+				i.mappings.Invalidate(memmap.MappableRange{newpgend, oldpgend}, memmap.InvalidateOpts{
+					// Compare Linux's mm/truncate.c:truncate_setsize() =>
+					// truncate_pagecache() =>
+					// mm/memory.c:unmap_mapping_range(evencows=1).
+					InvalidatePrivate: true,
+				})
+				i.mapsMu.Unlock()
+			}
+		}
 	}
 	if m&(linux.STATX_ATIME|linux.STATX_MTIME) != 0 {
 		ts := [2]syscall.Timespec{
@@ -464,9 +485,6 @@ func (i *inode) open(ctx context.Context, d *vfs.Dentry, mnt *vfs.Mount, flags u
 		return vfsfd, nil
 	}
 
-	// For simplicity, set offset to 0. Technically, we should
-	// only set to 0 on files that are not seekable (sockets, pipes, etc.),
-	// and use the offset from the host fd otherwise.
 	fd := &fileDescription{inode: i}
 	vfsfd := &fd.vfsfd
 	if err := vfsfd.Init(fd, flags, mnt, d, &vfs.FileDescriptionOptions{}); err != nil {
@@ -487,6 +505,13 @@ type fileDescription struct {
 	//
 	// inode is immutable after fileDescription creation.
 	inode *inode
+
+	// offsetMu protects offset.
+	offsetMu sync.Mutex
+
+	// offset specifies the current file offset. It is only meaningful when
+	// inode.seekable is true.
+	offset int64
 }
 
 // SetStat implements vfs.FileDescriptionImpl.
@@ -532,10 +557,10 @@ func (f *fileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts
 		return n, err
 	}
 	// TODO(gvisor.dev/issue/1672): Cache pages, when forced to do so.
-	i.offsetMu.Lock()
-	n, err := readFromHostFD(ctx, i.hostFD, dst, i.offset, opts.Flags)
-	i.offset += n
-	i.offsetMu.Unlock()
+	f.offsetMu.Lock()
+	n, err := readFromHostFD(ctx, i.hostFD, dst, f.offset, opts.Flags)
+	f.offset += n
+	f.offsetMu.Unlock()
 	return n, err
 }
 
@@ -572,10 +597,10 @@ func (f *fileDescription) Write(ctx context.Context, src usermem.IOSequence, opt
 	}
 	// TODO(gvisor.dev/issue/1672): Cache pages, when forced to do so.
 	// TODO(gvisor.dev/issue/1672): Write to end of file and update offset if O_APPEND is set on this file.
-	i.offsetMu.Lock()
-	n, err := writeToHostFD(ctx, i.hostFD, src, i.offset, opts.Flags)
-	i.offset += n
-	i.offsetMu.Unlock()
+	f.offsetMu.Lock()
+	n, err := writeToHostFD(ctx, i.hostFD, src, f.offset, opts.Flags)
+	f.offset += n
+	f.offsetMu.Unlock()
 	return n, err
 }
 
@@ -600,41 +625,41 @@ func (f *fileDescription) Seek(_ context.Context, offset int64, whence int32) (i
 		return 0, syserror.ESPIPE
 	}
 
-	i.offsetMu.Lock()
-	defer i.offsetMu.Unlock()
+	f.offsetMu.Lock()
+	defer f.offsetMu.Unlock()
 
 	switch whence {
 	case linux.SEEK_SET:
 		if offset < 0 {
-			return i.offset, syserror.EINVAL
+			return f.offset, syserror.EINVAL
 		}
-		i.offset = offset
+		f.offset = offset
 
 	case linux.SEEK_CUR:
-		// Check for overflow. Note that underflow cannot occur, since i.offset >= 0.
-		if offset > math.MaxInt64-i.offset {
-			return i.offset, syserror.EOVERFLOW
+		// Check for overflow. Note that underflow cannot occur, since f.offset >= 0.
+		if offset > math.MaxInt64-f.offset {
+			return f.offset, syserror.EOVERFLOW
 		}
-		if i.offset+offset < 0 {
-			return i.offset, syserror.EINVAL
+		if f.offset+offset < 0 {
+			return f.offset, syserror.EINVAL
 		}
-		i.offset += offset
+		f.offset += offset
 
 	case linux.SEEK_END:
 		var s syscall.Stat_t
 		if err := syscall.Fstat(i.hostFD, &s); err != nil {
-			return i.offset, err
+			return f.offset, err
 		}
 		size := s.Size
 
 		// Check for overflow. Note that underflow cannot occur, since size >= 0.
 		if offset > math.MaxInt64-size {
-			return i.offset, syserror.EOVERFLOW
+			return f.offset, syserror.EOVERFLOW
 		}
 		if size+offset < 0 {
-			return i.offset, syserror.EINVAL
+			return f.offset, syserror.EINVAL
 		}
-		i.offset = size + offset
+		f.offset = size + offset
 
 	case linux.SEEK_DATA, linux.SEEK_HOLE:
 		// Modifying the offset in the host file table should not matter, since
@@ -643,16 +668,16 @@ func (f *fileDescription) Seek(_ context.Context, offset int64, whence int32) (i
 		// For reading and writing, we always rely on our internal offset.
 		n, err := unix.Seek(i.hostFD, offset, int(whence))
 		if err != nil {
-			return i.offset, err
+			return f.offset, err
 		}
-		i.offset = n
+		f.offset = n
 
 	default:
 		// Invalid whence.
-		return i.offset, syserror.EINVAL
+		return f.offset, syserror.EINVAL
 	}
 
-	return i.offset, nil
+	return f.offset, nil
 }
 
 // Sync implements FileDescriptionImpl.
@@ -666,8 +691,9 @@ func (f *fileDescription) ConfigureMMap(_ context.Context, opts *memmap.MMapOpts
 	if !f.inode.canMap {
 		return syserror.ENODEV
 	}
-	// TODO(gvisor.dev/issue/1672): Implement ConfigureMMap and Mappable interface.
-	return syserror.ENODEV
+	i := f.inode
+	i.pf.fileMapperInitOnce.Do(i.pf.fileMapper.Init)
+	return vfs.GenericConfigureMMap(&f.vfsfd, i, opts)
 }
 
 // EventRegister implements waiter.Waitable.EventRegister.
diff --git a/pkg/sentry/fsimpl/host/host_state_autogen.go b/pkg/sentry/fsimpl/host/host_state_autogen.go
index 28bc79d04..28bc79d04 100755..100644
--- a/pkg/sentry/fsimpl/host/host_state_autogen.go
+++ b/pkg/sentry/fsimpl/host/host_state_autogen.go
diff --git a/pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go b/pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go
index b2d8c661f..b2d8c661f 100755..100644
--- a/pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go
+++ b/pkg/sentry/fsimpl/host/host_unsafe_state_autogen.go
diff --git a/pkg/sentry/fsimpl/host/ioctl_unsafe.go b/pkg/sentry/fsimpl/host/ioctl_unsafe.go
index 0983bf7d8..0983bf7d8 100755..100644
--- a/pkg/sentry/fsimpl/host/ioctl_unsafe.go
+++ b/pkg/sentry/fsimpl/host/ioctl_unsafe.go
diff --git a/pkg/sentry/fsimpl/host/mmap.go b/pkg/sentry/fsimpl/host/mmap.go
new file mode 100644
index 000000000..8545a82f0
--- /dev/null
+++ b/pkg/sentry/fsimpl/host/mmap.go
@@ -0,0 +1,132 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package host
+
+import (
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/safemem"
+	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
+	"gvisor.dev/gvisor/pkg/sentry/memmap"
+	"gvisor.dev/gvisor/pkg/sentry/platform"
+	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+// inodePlatformFile implements platform.File. It exists solely because inode
+// cannot implement both kernfs.Inode.IncRef and platform.File.IncRef.
+//
+// inodePlatformFile should only be used if inode.canMap is true.
+type inodePlatformFile struct {
+	*inode
+
+	// fdRefsMu protects fdRefs.
+	fdRefsMu sync.Mutex
+
+	// fdRefs counts references on platform.File offsets. It is used solely for
+	// memory accounting.
+	fdRefs fsutil.FrameRefSet
+
+	// fileMapper caches mappings of the host file represented by this inode.
+	fileMapper fsutil.HostFileMapper
+
+	// fileMapperInitOnce is used to lazily initialize fileMapper.
+	fileMapperInitOnce sync.Once
+}
+
+// IncRef implements platform.File.IncRef.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inodePlatformFile) IncRef(fr platform.FileRange) {
+	i.fdRefsMu.Lock()
+	i.fdRefs.IncRefAndAccount(fr)
+	i.fdRefsMu.Unlock()
+}
+
+// DecRef implements platform.File.DecRef.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inodePlatformFile) DecRef(fr platform.FileRange) {
+	i.fdRefsMu.Lock()
+	i.fdRefs.DecRefAndAccount(fr)
+	i.fdRefsMu.Unlock()
+}
+
+// MapInternal implements platform.File.MapInternal.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inodePlatformFile) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
+	return i.fileMapper.MapInternal(fr, i.hostFD, at.Write)
+}
+
+// FD implements platform.File.FD.
+func (i *inodePlatformFile) FD() int {
+	return i.hostFD
+}
+
+// AddMapping implements memmap.Mappable.AddMapping.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error {
+	i.mapsMu.Lock()
+	mapped := i.mappings.AddMapping(ms, ar, offset, writable)
+	for _, r := range mapped {
+		i.pf.fileMapper.IncRefOn(r)
+	}
+	i.mapsMu.Unlock()
+	return nil
+}
+
+// RemoveMapping implements memmap.Mappable.RemoveMapping.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) {
+	i.mapsMu.Lock()
+	unmapped := i.mappings.RemoveMapping(ms, ar, offset, writable)
+	for _, r := range unmapped {
+		i.pf.fileMapper.DecRefOn(r)
+	}
+	i.mapsMu.Unlock()
+}
+
+// CopyMapping implements memmap.Mappable.CopyMapping.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error {
+	return i.AddMapping(ctx, ms, dstAR, offset, writable)
+}
+
+// Translate implements memmap.Mappable.Translate.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) {
+	mr := optional
+	return []memmap.Translation{
+		{
+			Source: mr,
+			File:   &i.pf,
+			Offset: mr.Start,
+			Perms:  usermem.AnyAccess,
+		},
+	}, nil
+}
+
+// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) InvalidateUnsavable(ctx context.Context) error {
+	// We expect the same host fd across save/restore, so all translations
+	// should be valid.
+	return nil
+}
diff --git a/pkg/sentry/fsimpl/host/socket.go b/pkg/sentry/fsimpl/host/socket.go
index 38f1fbfba..38f1fbfba 100755..100644
--- a/pkg/sentry/fsimpl/host/socket.go
+++ b/pkg/sentry/fsimpl/host/socket.go
diff --git a/pkg/sentry/fsimpl/host/socket_iovec.go b/pkg/sentry/fsimpl/host/socket_iovec.go
index 584c247d2..584c247d2 100755..100644
--- a/pkg/sentry/fsimpl/host/socket_iovec.go
+++ b/pkg/sentry/fsimpl/host/socket_iovec.go
diff --git a/pkg/sentry/fsimpl/host/socket_unsafe.go b/pkg/sentry/fsimpl/host/socket_unsafe.go
index 35ded24bc..35ded24bc 100755..100644
--- a/pkg/sentry/fsimpl/host/socket_unsafe.go
+++ b/pkg/sentry/fsimpl/host/socket_unsafe.go
diff --git a/pkg/sentry/fsimpl/host/tty.go b/pkg/sentry/fsimpl/host/tty.go
index 68af6e5af..68af6e5af 100755..100644
--- a/pkg/sentry/fsimpl/host/tty.go
+++ b/pkg/sentry/fsimpl/host/tty.go
diff --git a/pkg/sentry/fsimpl/host/util.go b/pkg/sentry/fsimpl/host/util.go
index 2bc757b1a..2bc757b1a 100755..100644
--- a/pkg/sentry/fsimpl/host/util.go
+++ b/pkg/sentry/fsimpl/host/util.go
diff --git a/pkg/sentry/fsimpl/host/util_unsafe.go b/pkg/sentry/fsimpl/host/util_unsafe.go
index 5136ac844..5136ac844 100755..100644
--- a/pkg/sentry/fsimpl/host/util_unsafe.go
+++ b/pkg/sentry/fsimpl/host/util_unsafe.go
diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
index 1568a9d49..1568a9d49 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
+++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
diff --git a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
index 8284e76a7..8284e76a7 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index 4a12ae245..4a12ae245 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
diff --git a/pkg/sentry/fsimpl/kernfs/fstree.go b/pkg/sentry/fsimpl/kernfs/fstree.go
index 4c4033462..4c4033462 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/fstree.go
+++ b/pkg/sentry/fsimpl/kernfs/fstree.go
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 982daa2e6..982daa2e6 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index a83151ad3..a83151ad3 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go b/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go
index 299ad87fa..299ad87fa 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go
diff --git a/pkg/sentry/fsimpl/kernfs/slot_list.go b/pkg/sentry/fsimpl/kernfs/slot_list.go
index 09c30bca7..09c30bca7 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/slot_list.go
+++ b/pkg/sentry/fsimpl/kernfs/slot_list.go
diff --git a/pkg/sentry/fsimpl/kernfs/symlink.go b/pkg/sentry/fsimpl/kernfs/symlink.go
index 2ab3f53fd..2ab3f53fd 100755..100644
--- a/pkg/sentry/fsimpl/kernfs/symlink.go
+++ b/pkg/sentry/fsimpl/kernfs/symlink.go
diff --git a/pkg/sentry/fsimpl/pipefs/pipefs.go b/pkg/sentry/fsimpl/pipefs/pipefs.go
index cab771211..cab771211 100755..100644
--- a/pkg/sentry/fsimpl/pipefs/pipefs.go
+++ b/pkg/sentry/fsimpl/pipefs/pipefs.go
diff --git a/pkg/sentry/fsimpl/pipefs/pipefs_state_autogen.go b/pkg/sentry/fsimpl/pipefs/pipefs_state_autogen.go
index e3e3887cd..e3e3887cd 100755..100644
--- a/pkg/sentry/fsimpl/pipefs/pipefs_state_autogen.go
+++ b/pkg/sentry/fsimpl/pipefs/pipefs_state_autogen.go
diff --git a/pkg/sentry/fsimpl/proc/filesystem.go b/pkg/sentry/fsimpl/proc/filesystem.go
index 609210253..609210253 100755..100644
--- a/pkg/sentry/fsimpl/proc/filesystem.go
+++ b/pkg/sentry/fsimpl/proc/filesystem.go
diff --git a/pkg/sentry/fsimpl/proc/proc_state_autogen.go b/pkg/sentry/fsimpl/proc/proc_state_autogen.go
index 168e61390..168e61390 100755..100644
--- a/pkg/sentry/fsimpl/proc/proc_state_autogen.go
+++ b/pkg/sentry/fsimpl/proc/proc_state_autogen.go
diff --git a/pkg/sentry/fsimpl/proc/subtasks.go b/pkg/sentry/fsimpl/proc/subtasks.go
index 36a911db4..36a911db4 100755..100644
--- a/pkg/sentry/fsimpl/proc/subtasks.go
+++ b/pkg/sentry/fsimpl/proc/subtasks.go
diff --git a/pkg/sentry/fsimpl/proc/task.go b/pkg/sentry/fsimpl/proc/task.go
index 482055db1..482055db1 100755..100644
--- a/pkg/sentry/fsimpl/proc/task.go
+++ b/pkg/sentry/fsimpl/proc/task.go
diff --git a/pkg/sentry/fsimpl/proc/task_fds.go b/pkg/sentry/fsimpl/proc/task_fds.go
index 44ccc9e4a..44ccc9e4a 100755..100644
--- a/pkg/sentry/fsimpl/proc/task_fds.go
+++ b/pkg/sentry/fsimpl/proc/task_fds.go
diff --git a/pkg/sentry/fsimpl/proc/task_files.go b/pkg/sentry/fsimpl/proc/task_files.go
index 2f297e48a..2f297e48a 100755..100644
--- a/pkg/sentry/fsimpl/proc/task_files.go
+++ b/pkg/sentry/fsimpl/proc/task_files.go
diff --git a/pkg/sentry/fsimpl/proc/task_net.go b/pkg/sentry/fsimpl/proc/task_net.go
index 6bde27376..6bde27376 100755..100644
--- a/pkg/sentry/fsimpl/proc/task_net.go
+++ b/pkg/sentry/fsimpl/proc/task_net.go
diff --git a/pkg/sentry/fsimpl/proc/tasks.go b/pkg/sentry/fsimpl/proc/tasks.go
index b51d43954..b51d43954 100755..100644
--- a/pkg/sentry/fsimpl/proc/tasks.go
+++ b/pkg/sentry/fsimpl/proc/tasks.go
diff --git a/pkg/sentry/fsimpl/proc/tasks_files.go b/pkg/sentry/fsimpl/proc/tasks_files.go
index 7d8983aa5..7d8983aa5 100755..100644
--- a/pkg/sentry/fsimpl/proc/tasks_files.go
+++ b/pkg/sentry/fsimpl/proc/tasks_files.go
diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go
index 6dac2afa4..6dac2afa4 100755..100644
--- a/pkg/sentry/fsimpl/proc/tasks_sys.go
+++ b/pkg/sentry/fsimpl/proc/tasks_sys.go
diff --git a/pkg/sentry/fsimpl/signalfd/signalfd.go b/pkg/sentry/fsimpl/signalfd/signalfd.go
index d29ef3f83..d29ef3f83 100755..100644
--- a/pkg/sentry/fsimpl/signalfd/signalfd.go
+++ b/pkg/sentry/fsimpl/signalfd/signalfd.go
diff --git a/pkg/sentry/fsimpl/signalfd/signalfd_state_autogen.go b/pkg/sentry/fsimpl/signalfd/signalfd_state_autogen.go
index c3d9b2ffb..c3d9b2ffb 100755..100644
--- a/pkg/sentry/fsimpl/signalfd/signalfd_state_autogen.go
+++ b/pkg/sentry/fsimpl/signalfd/signalfd_state_autogen.go
diff --git a/pkg/sentry/fsimpl/sockfs/sockfs.go b/pkg/sentry/fsimpl/sockfs/sockfs.go
index ee0828a15..ee0828a15 100755..100644
--- a/pkg/sentry/fsimpl/sockfs/sockfs.go
+++ b/pkg/sentry/fsimpl/sockfs/sockfs.go
diff --git a/pkg/sentry/fsimpl/sockfs/sockfs_state_autogen.go b/pkg/sentry/fsimpl/sockfs/sockfs_state_autogen.go
index 8d5b85e2c..8d5b85e2c 100755..100644
--- a/pkg/sentry/fsimpl/sockfs/sockfs_state_autogen.go
+++ b/pkg/sentry/fsimpl/sockfs/sockfs_state_autogen.go
diff --git a/pkg/sentry/fsimpl/sys/sys.go b/pkg/sentry/fsimpl/sys/sys.go
index 0af373604..0af373604 100755..100644
--- a/pkg/sentry/fsimpl/sys/sys.go
+++ b/pkg/sentry/fsimpl/sys/sys.go
diff --git a/pkg/sentry/fsimpl/sys/sys_state_autogen.go b/pkg/sentry/fsimpl/sys/sys_state_autogen.go
index 8866ddff9..8866ddff9 100755..100644
--- a/pkg/sentry/fsimpl/sys/sys_state_autogen.go
+++ b/pkg/sentry/fsimpl/sys/sys_state_autogen.go
diff --git a/pkg/sentry/fsimpl/timerfd/timerfd.go b/pkg/sentry/fsimpl/timerfd/timerfd.go
index 60c92d626..60c92d626 100755..100644
--- a/pkg/sentry/fsimpl/timerfd/timerfd.go
+++ b/pkg/sentry/fsimpl/timerfd/timerfd.go
diff --git a/pkg/sentry/fsimpl/timerfd/timerfd_state_autogen.go b/pkg/sentry/fsimpl/timerfd/timerfd_state_autogen.go
index 4e5976369..4e5976369 100755..100644
--- a/pkg/sentry/fsimpl/timerfd/timerfd_state_autogen.go
+++ b/pkg/sentry/fsimpl/timerfd/timerfd_state_autogen.go
diff --git a/pkg/sentry/fsimpl/tmpfs/dentry_list.go b/pkg/sentry/fsimpl/tmpfs/dentry_list.go
index 9af621dd3..9af621dd3 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/dentry_list.go
+++ b/pkg/sentry/fsimpl/tmpfs/dentry_list.go
diff --git a/pkg/sentry/fsimpl/tmpfs/device_file.go b/pkg/sentry/fsimpl/tmpfs/device_file.go
index 83bf885ee..83bf885ee 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/device_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/device_file.go
diff --git a/pkg/sentry/fsimpl/tmpfs/directory.go b/pkg/sentry/fsimpl/tmpfs/directory.go
index f2399981b..f2399981b 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/directory.go
+++ b/pkg/sentry/fsimpl/tmpfs/directory.go
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index 80fa7b29d..80fa7b29d 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
diff --git a/pkg/sentry/fsimpl/tmpfs/fstree.go b/pkg/sentry/fsimpl/tmpfs/fstree.go
index fab366345..fab366345 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/fstree.go
+++ b/pkg/sentry/fsimpl/tmpfs/fstree.go
diff --git a/pkg/sentry/fsimpl/tmpfs/named_pipe.go b/pkg/sentry/fsimpl/tmpfs/named_pipe.go
index 8d77b3fa8..8d77b3fa8 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/named_pipe.go
+++ b/pkg/sentry/fsimpl/tmpfs/named_pipe.go
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go
index 3f433d666..fee174375 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file.go
@@ -312,7 +312,7 @@ func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
 	f := fd.inode().impl.(*regularFile)
 	if end := offset + srclen; end < offset {
 		// Overflow.
-		return 0, syserror.EFBIG
+		return 0, syserror.EINVAL
 	}
 
 	var err error
diff --git a/pkg/sentry/fsimpl/tmpfs/socket_file.go b/pkg/sentry/fsimpl/tmpfs/socket_file.go
index 25c2321af..25c2321af 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/socket_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/socket_file.go
diff --git a/pkg/sentry/fsimpl/tmpfs/symlink.go b/pkg/sentry/fsimpl/tmpfs/symlink.go
index 47e075ed4..47e075ed4 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/symlink.go
+++ b/pkg/sentry/fsimpl/tmpfs/symlink.go
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index 1e781aecd..1e781aecd 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go b/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
index 10d8b49a6..10d8b49a6 100755..100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go