From 226fec2ce90233da445603322f6efaee639bdcb7 Mon Sep 17 00:00:00 2001
From: Mei Gui <71293871+xinmeigui-db@users.noreply.github.com>
Date: Tue, 26 Jul 2022 00:34:00 -0700
Subject: [PATCH] Pass OpenFlags for OpenFileOp followups (#129)

---
 conversions.go              |  3 +--
 fuseops/ops.go              |  2 +-
 samples/memfs/inode.go      |  7 ++++++-
 samples/memfs/memfs.go      | 41 +++++++++++++++++++++++++++++--------
 samples/memfs/memfs_test.go | 29 ++++++++++++++++++++------
 5 files changed, 63 insertions(+), 19 deletions(-)

diff --git a/conversions.go b/conversions.go
index ddb57d5..fbcc7bb 100644
--- a/conversions.go
+++ b/conversions.go
@@ -299,11 +299,10 @@ func convertInMessage(
 		if in == nil {
 			return nil, errors.New("Corrupt OpOpen")
 		}
-		openFlags := fusekernel.OpenFlags(in.Flags)
 
 		o = &fuseops.OpenFileOp{
 			Inode:     fuseops.InodeID(inMsg.Header().Nodeid),
-			OpenFlags: &openFlags,
+			OpenFlags: fusekernel.OpenFlags(in.Flags),
 			OpContext: fuseops.OpContext{Pid: inMsg.Header().Pid},
 		}
 
diff --git a/fuseops/ops.go b/fuseops/ops.go
index 0f51b25..e92db76 100644
--- a/fuseops/ops.go
+++ b/fuseops/ops.go
@@ -648,7 +648,7 @@ type OpenFileOp struct {
 	// advance, for example, because contents are generated on the fly.
 	UseDirectIO bool
 
-	OpenFlags *fusekernel.OpenFlags
+	OpenFlags fusekernel.OpenFlags
 
 	OpContext OpContext
 }
diff --git a/samples/memfs/inode.go b/samples/memfs/inode.go
index 170b5f2..10ed54f 100644
--- a/samples/memfs/inode.go
+++ b/samples/memfs/inode.go
@@ -33,6 +33,10 @@ type inode struct {
 	// Mutable state
 	/////////////////////////
 
+	// Name of the inode, only contains relative path.
+	// For example, if the full path for an inode is /foo/bar/f1, its name is f1.
+	name string
+
 	// The current attributes of this inode.
 	//
 	// INVARIANT: attrs.Mode &^ (os.ModePerm|os.ModeDir|os.ModeSymlink) == 0
@@ -73,7 +77,7 @@ type inode struct {
 
 // Create a new inode with the supplied attributes, which need not contain
 // time-related information (the inode object will take care of that).
-func newInode(attrs fuseops.InodeAttributes) *inode {
+func newInode(attrs fuseops.InodeAttributes, name string) *inode {
 	// Update time info.
 	now := time.Now()
 	attrs.Mtime = now
@@ -81,6 +85,7 @@ func newInode(attrs fuseops.InodeAttributes) *inode {
 
 	// Create the object.
 	return &inode{
+		name:   name,
 		attrs:  attrs,
 		xattrs: make(map[string][]byte),
 	}
diff --git a/samples/memfs/memfs.go b/samples/memfs/memfs.go
index 3fb0206..3f22206 100644
--- a/samples/memfs/memfs.go
+++ b/samples/memfs/memfs.go
@@ -16,6 +16,7 @@ package memfs
 
 import (
 	"context"
+	"encoding/binary"
 	"fmt"
 	"io"
 	"os"
@@ -29,6 +30,11 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+const (
+	FileOpenFlagsXattrName     = "fileOpenFlagsXattr"
+	CheckFileOpenFlagsFileName = "checkFileOpenFlags"
+)
+
 type memFS struct {
 	fuseutil.NotImplementedFileSystem
 
@@ -85,7 +91,7 @@ func NewMemFS(
 		Gid:  gid,
 	}
 
-	fs.inodes[fuseops.RootInodeID] = newInode(rootAttrs)
+	fs.inodes[fuseops.RootInodeID] = newInode(rootAttrs, "")
 
 	// Set up invariant checking.
 	fs.mu = syncutil.NewInvariantMutex(fs.checkInvariants)
@@ -157,9 +163,9 @@ func (fs *memFS) getInodeOrDie(id fuseops.InodeID) *inode {
 //
 // LOCKS_REQUIRED(fs.mu)
 func (fs *memFS) allocateInode(
-	attrs fuseops.InodeAttributes) (id fuseops.InodeID, inode *inode) {
+	attrs fuseops.InodeAttributes, name string) (id fuseops.InodeID, inode *inode) {
 	// Create the inode.
-	inode = newInode(attrs)
+	inode = newInode(attrs, name)
 
 	// Re-use a free ID if possible. Otherwise mint a new one.
 	numFree := len(fs.freeInodes)
@@ -310,7 +316,7 @@ func (fs *memFS) MkDir(
 	}
 
 	// Allocate a child.
-	childID, child := fs.allocateInode(childAttrs)
+	childID, child := fs.allocateInode(childAttrs, op.Name)
 
 	// Add an entry in the parent.
 	parent.AddChild(childID, op.Name, fuseutil.DT_Directory)
@@ -371,7 +377,7 @@ func (fs *memFS) createFile(
 	}
 
 	// Allocate a child.
-	childID, child := fs.allocateInode(childAttrs)
+	childID, child := fs.allocateInode(childAttrs, name)
 
 	// Add an entry in the parent.
 	parent.AddChild(childID, name, fuseutil.DT_File)
@@ -438,7 +444,7 @@ func (fs *memFS) CreateSymlink(
 	}
 
 	// Allocate a child.
-	childID, child := fs.allocateInode(childAttrs)
+	childID, child := fs.allocateInode(childAttrs, op.Name)
 
 	// Set up its target.
 	child.target = op.Target
@@ -661,9 +667,6 @@ func (fs *memFS) OpenFile(
 		// OpenFileOp should have a valid pid in context.
 		return fuse.EINVAL
 	}
-	if op.OpenFlags == nil {
-		return fuse.EINVAL
-	}
 
 	fs.mu.Lock()
 	defer fs.mu.Unlock()
@@ -677,6 +680,21 @@ func (fs *memFS) OpenFile(
 		panic("Found non-file.")
 	}
 
+	if inode.name == CheckFileOpenFlagsFileName {
+		// For testing purpose only.
+		// Set attribute (name=fileOpenFlagsXattr, value=OpenFlags) to test whether
+		// we set OpenFlags correctly. The value is checked in test with getXattr.
+		value := make([]byte, 4)
+		binary.LittleEndian.PutUint32(value, uint32(op.OpenFlags))
+		err := fs.setXattrHelper(inode, &fuseops.SetXattrOp{
+			Name:  FileOpenFlagsXattrName,
+			Value: value,
+		})
+		if err != nil {
+			panic("unable to set fileOpenFlagsXattr")
+		}
+	}
+
 	return nil
 }
 
@@ -832,6 +850,11 @@ func (fs *memFS) SetXattr(ctx context.Context,
 	defer fs.mu.Unlock()
 	inode := fs.getInodeOrDie(op.Inode)
 
+	return fs.setXattrHelper(inode, op)
+}
+
+// Required to hold fs.mu
+func (fs *memFS) setXattrHelper(inode *inode, op *fuseops.SetXattrOp) error {
 	_, ok := inode.xattrs[op.Name]
 
 	switch op.Flags {
diff --git a/samples/memfs/memfs_test.go b/samples/memfs/memfs_test.go
index aa1dc47..74e272a 100644
--- a/samples/memfs/memfs_test.go
+++ b/samples/memfs/memfs_test.go
@@ -16,6 +16,7 @@ package memfs_test
 
 import (
 	"bytes"
+	"encoding/binary"
 	"io"
 	"io/ioutil"
 	"os"
@@ -31,6 +32,7 @@ import (
 	fallocate "github.com/detailyang/go-fallocate"
 	"github.com/jacobsa/fuse"
 	"github.com/jacobsa/fuse/fusetesting"
+	"github.com/jacobsa/fuse/internal/fusekernel"
 	"github.com/jacobsa/fuse/samples"
 	"github.com/jacobsa/fuse/samples/memfs"
 	. "github.com/jacobsa/oglematchers"
@@ -88,6 +90,15 @@ func applyUmask(m os.FileMode) os.FileMode {
 	return m &^ os.FileMode(umask)
 }
 
+func (t *MemFSTest) checkOpenFlagsXattr(
+	fileName string, expectedOpenFlags fusekernel.OpenFlags) {
+	dest := make([]byte, 4)
+	_, err := unix.Getxattr(fileName, memfs.FileOpenFlagsXattrName, dest)
+	AssertEq(nil, err)
+	openFlags := binary.LittleEndian.Uint32(dest)
+	AssertEq(openFlags, uint32(expectedOpenFlags))
+}
+
 ////////////////////////////////////////////////////////////////////////
 // Boilerplate
 ////////////////////////////////////////////////////////////////////////
@@ -292,7 +303,7 @@ func (t *MemFSTest) CreateNewFile_InRoot() {
 	var stat *syscall.Stat_t
 
 	// Write a file.
-	fileName := path.Join(t.Dir, "foo")
+	fileName := path.Join(t.Dir, memfs.CheckFileOpenFlagsFileName)
 	const contents = "Hello\x00world"
 
 	createTime := time.Now()
@@ -304,7 +315,7 @@ func (t *MemFSTest) CreateNewFile_InRoot() {
 	stat = fi.Sys().(*syscall.Stat_t)
 
 	AssertEq(nil, err)
-	ExpectEq("foo", fi.Name())
+	ExpectEq(memfs.CheckFileOpenFlagsFileName, fi.Name())
 	ExpectEq(len(contents), fi.Size())
 	ExpectEq(applyUmask(0400), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(createTime, timeSlop))
@@ -321,6 +332,7 @@ func (t *MemFSTest) CreateNewFile_InRoot() {
 	slice, err := ioutil.ReadFile(fileName)
 	AssertEq(nil, err)
 	ExpectEq(contents, string(slice))
+	t.checkOpenFlagsXattr(fileName, fusekernel.OpenReadOnly)
 }
 
 func (t *MemFSTest) CreateNewFile_InSubDir() {
@@ -372,7 +384,7 @@ func (t *MemFSTest) ModifyExistingFile_InRoot() {
 	var stat *syscall.Stat_t
 
 	// Write a file.
-	fileName := path.Join(t.Dir, "foo")
+	fileName := path.Join(t.Dir, memfs.CheckFileOpenFlagsFileName)
 
 	createTime := time.Now()
 	err = ioutil.WriteFile(fileName, []byte("Hello, world!"), 0600)
@@ -382,6 +394,7 @@ func (t *MemFSTest) ModifyExistingFile_InRoot() {
 	f, err := os.OpenFile(fileName, os.O_WRONLY, 0400)
 	t.ToClose = append(t.ToClose, f)
 	AssertEq(nil, err)
+	t.checkOpenFlagsXattr(fileName, fusekernel.OpenWriteOnly)
 
 	modifyTime := time.Now()
 	n, err = f.WriteAt([]byte("H"), 0)
@@ -393,7 +406,7 @@ func (t *MemFSTest) ModifyExistingFile_InRoot() {
 	stat = fi.Sys().(*syscall.Stat_t)
 
 	AssertEq(nil, err)
-	ExpectEq("foo", fi.Name())
+	ExpectEq(memfs.CheckFileOpenFlagsFileName, fi.Name())
 	ExpectEq(len("Hello, world!"), fi.Size())
 	ExpectEq(applyUmask(0600), fi.Mode())
 	ExpectThat(fi, fusetesting.MtimeIsWithin(modifyTime, timeSlop))
@@ -410,6 +423,7 @@ func (t *MemFSTest) ModifyExistingFile_InRoot() {
 	slice, err := ioutil.ReadFile(fileName)
 	AssertEq(nil, err)
 	ExpectEq("Hello, world!", string(slice))
+	t.checkOpenFlagsXattr(fileName, fusekernel.OpenReadOnly)
 }
 
 func (t *MemFSTest) ModifyExistingFile_InSubDir() {
@@ -832,7 +846,7 @@ func (t *MemFSTest) AppendMode() {
 	buf := make([]byte, 1024)
 
 	// Create a file with some contents.
-	fileName := path.Join(t.Dir, "foo")
+	fileName := path.Join(t.Dir, memfs.CheckFileOpenFlagsFileName)
 	err = ioutil.WriteFile(fileName, []byte("Jello, "), 0600)
 	AssertEq(nil, err)
 
@@ -840,6 +854,7 @@ func (t *MemFSTest) AppendMode() {
 	f, err := os.OpenFile(fileName, os.O_RDWR|os.O_APPEND, 0600)
 	t.ToClose = append(t.ToClose, f)
 	AssertEq(nil, err)
+	t.checkOpenFlagsXattr(fileName, fusekernel.OpenReadWrite)
 
 	// Seek to somewhere silly and then write.
 	off, err = f.Seek(2, 0)
@@ -907,7 +922,7 @@ func (t *MemFSTest) ReadsPastEndOfFile() {
 
 func (t *MemFSTest) Truncate_Smaller() {
 	var err error
-	fileName := path.Join(t.Dir, "foo")
+	fileName := path.Join(t.Dir, memfs.CheckFileOpenFlagsFileName)
 
 	// Create a file.
 	err = ioutil.WriteFile(fileName, []byte("taco"), 0600)
@@ -917,6 +932,7 @@ func (t *MemFSTest) Truncate_Smaller() {
 	f, err := os.OpenFile(fileName, os.O_RDWR, 0)
 	t.ToClose = append(t.ToClose, f)
 	AssertEq(nil, err)
+	t.checkOpenFlagsXattr(fileName, fusekernel.OpenReadWrite)
 
 	// Truncate it.
 	err = f.Truncate(2)
@@ -931,6 +947,7 @@ func (t *MemFSTest) Truncate_Smaller() {
 	contents, err := ioutil.ReadFile(fileName)
 	AssertEq(nil, err)
 	ExpectEq("ta", string(contents))
+	t.checkOpenFlagsXattr(fileName, fusekernel.OpenReadOnly)
 }
 
 func (t *MemFSTest) Truncate_SameSize() {