From b2ae7ea1bb207eddadd7962080e7bd0b8634db96 Mon Sep 17 00:00:00 2001 From: Nayana Bidari Date: Mon, 3 Aug 2020 13:33:47 -0700 Subject: Plumbing context.Context to DecRef() and Release(). context is passed to DecRef() and Release() which is needed for SO_LINGER implementation. PiperOrigin-RevId: 324672584 --- pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go | 2 +- pkg/sentry/fsimpl/kernfs/fd_impl_util.go | 2 +- pkg/sentry/fsimpl/kernfs/filesystem.go | 68 +++++++++++++------------- pkg/sentry/fsimpl/kernfs/inode_impl_util.go | 10 ++-- pkg/sentry/fsimpl/kernfs/kernfs.go | 26 +++++----- pkg/sentry/fsimpl/kernfs/kernfs_test.go | 18 +++---- 6 files changed, 63 insertions(+), 63 deletions(-) (limited to 'pkg/sentry/fsimpl/kernfs') diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go index c6c4472e7..12adf727a 100644 --- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go +++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go @@ -122,7 +122,7 @@ func (fd *DynamicBytesFD) PWrite(ctx context.Context, src usermem.IOSequence, of } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *DynamicBytesFD) Release() {} +func (fd *DynamicBytesFD) Release(context.Context) {} // Stat implements vfs.FileDescriptionImpl.Stat. func (fd *DynamicBytesFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { diff --git a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go index 1d37ccb98..fcee6200a 100644 --- a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go +++ b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go @@ -113,7 +113,7 @@ func (fd *GenericDirectoryFD) PWrite(ctx context.Context, src usermem.IOSequence } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *GenericDirectoryFD) Release() {} +func (fd *GenericDirectoryFD) Release(context.Context) {} func (fd *GenericDirectoryFD) filesystem() *vfs.Filesystem { return fd.vfsfd.VirtualDentry().Mount().Filesystem() diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go index 61a36cff9..d7edb6342 100644 --- a/pkg/sentry/fsimpl/kernfs/filesystem.go +++ b/pkg/sentry/fsimpl/kernfs/filesystem.go @@ -56,13 +56,13 @@ afterSymlink: return vfsd, nil } if name == ".." { - if isRoot, err := rp.CheckRoot(vfsd); err != nil { + if isRoot, err := rp.CheckRoot(ctx, vfsd); err != nil { return nil, err } else if isRoot || d.parent == nil { rp.Advance() return vfsd, nil } - if err := rp.CheckMount(&d.parent.vfsd); err != nil { + if err := rp.CheckMount(ctx, &d.parent.vfsd); err != nil { return nil, err } rp.Advance() @@ -77,7 +77,7 @@ afterSymlink: if err != nil { return nil, err } - if err := rp.CheckMount(&next.vfsd); err != nil { + if err := rp.CheckMount(ctx, &next.vfsd); err != nil { return nil, err } // Resolve any symlink at current path component. @@ -88,7 +88,7 @@ afterSymlink: } if targetVD.Ok() { err := rp.HandleJump(targetVD) - targetVD.DecRef() + targetVD.DecRef(ctx) if err != nil { return nil, err } @@ -116,7 +116,7 @@ func (fs *Filesystem) revalidateChildLocked(ctx context.Context, vfsObj *vfs.Vir // Cached dentry exists, revalidate. if !child.inode.Valid(ctx) { delete(parent.children, name) - vfsObj.InvalidateDentry(&child.vfsd) + vfsObj.InvalidateDentry(ctx, &child.vfsd) fs.deferDecRef(&child.vfsd) // Reference from Lookup. child = nil } @@ -234,7 +234,7 @@ func checkDeleteLocked(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Den } // Release implements vfs.FilesystemImpl.Release. -func (fs *Filesystem) Release() { +func (fs *Filesystem) Release(context.Context) { } // Sync implements vfs.FilesystemImpl.Sync. @@ -246,7 +246,7 @@ func (fs *Filesystem) Sync(ctx context.Context) error { // AccessAt implements vfs.Filesystem.Impl.AccessAt. func (fs *Filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds *auth.Credentials, ats vfs.AccessTypes) error { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() _, inode, err := fs.walkExistingLocked(ctx, rp) @@ -259,7 +259,7 @@ func (fs *Filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds // GetDentryAt implements vfs.FilesystemImpl.GetDentryAt. func (fs *Filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() vfsd, inode, err := fs.walkExistingLocked(ctx, rp) if err != nil { @@ -282,7 +282,7 @@ func (fs *Filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op // GetParentDentryAt implements vfs.FilesystemImpl.GetParentDentryAt. func (fs *Filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() vfsd, _, err := fs.walkParentDirLocked(ctx, rp) if err != nil { @@ -300,7 +300,7 @@ func (fs *Filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs. fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -337,7 +337,7 @@ func (fs *Filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts v fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -365,7 +365,7 @@ func (fs *Filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -397,7 +397,7 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf // Do not create new file. if opts.Flags&linux.O_CREAT == 0 { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() vfsd, inode, err := fs.walkExistingLocked(ctx, rp) if err != nil { @@ -429,7 +429,7 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf } afterTrailingSymlink: parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return nil, err } @@ -483,7 +483,7 @@ afterTrailingSymlink: } if targetVD.Ok() { err := rp.HandleJump(targetVD) - targetVD.DecRef() + targetVD.DecRef(ctx) if err != nil { return nil, err } @@ -507,7 +507,7 @@ func (fs *Filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (st fs.mu.RLock() d, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return "", err } @@ -526,7 +526,7 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa noReplace := opts.Flags&linux.RENAME_NOREPLACE != 0 fs.mu.Lock() - defer fs.processDeferredDecRefsLocked() + defer fs.processDeferredDecRefsLocked(ctx) defer fs.mu.Unlock() // Resolve the destination directory first to verify that it's on this @@ -584,7 +584,7 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa } mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) virtfs := rp.VirtualFilesystem() // We can't deadlock here due to lock ordering because we're protected from @@ -615,7 +615,7 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa dstDir.children = make(map[string]*Dentry) } dstDir.children[pc] = src - virtfs.CommitRenameReplaceDentry(srcVFSD, replaced) + virtfs.CommitRenameReplaceDentry(ctx, srcVFSD, replaced) return nil } @@ -624,7 +624,7 @@ func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error fs.mu.Lock() defer fs.mu.Unlock() vfsd, inode, err := fs.walkExistingLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -648,7 +648,7 @@ func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error defer parentDentry.dirMu.Unlock() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) if err := virtfs.PrepareDeleteDentry(mntns, vfsd); err != nil { return err } @@ -656,7 +656,7 @@ func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error virtfs.AbortDeleteDentry(vfsd) return err } - virtfs.CommitDeleteDentry(vfsd) + virtfs.CommitDeleteDentry(ctx, vfsd) return nil } @@ -665,7 +665,7 @@ func (fs *Filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts fs.mu.RLock() _, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return err } @@ -680,7 +680,7 @@ func (fs *Filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf fs.mu.RLock() _, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return linux.Statx{}, err } @@ -692,7 +692,7 @@ func (fs *Filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linu fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return linux.Statfs{}, err } @@ -708,7 +708,7 @@ func (fs *Filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, targ fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -733,7 +733,7 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error fs.mu.Lock() defer fs.mu.Unlock() vfsd, _, err := fs.walkExistingLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -753,7 +753,7 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error parentDentry.dirMu.Lock() defer parentDentry.dirMu.Unlock() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) if err := virtfs.PrepareDeleteDentry(mntns, vfsd); err != nil { return err } @@ -761,7 +761,7 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error virtfs.AbortDeleteDentry(vfsd) return err } - virtfs.CommitDeleteDentry(vfsd) + virtfs.CommitDeleteDentry(ctx, vfsd) return nil } @@ -770,7 +770,7 @@ func (fs *Filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath fs.mu.RLock() _, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return nil, err } @@ -785,7 +785,7 @@ func (fs *Filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, si fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return nil, err } @@ -798,7 +798,7 @@ func (fs *Filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return "", err } @@ -811,7 +811,7 @@ func (fs *Filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return err } @@ -824,7 +824,7 @@ func (fs *Filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return err } diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go index 579e627f0..c3efcf3ec 100644 --- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go +++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go @@ -40,7 +40,7 @@ func (InodeNoopRefCount) IncRef() { } // DecRef implements Inode.DecRef. -func (InodeNoopRefCount) DecRef() { +func (InodeNoopRefCount) DecRef(context.Context) { } // TryIncRef implements Inode.TryIncRef. @@ -49,7 +49,7 @@ func (InodeNoopRefCount) TryIncRef() bool { } // Destroy implements Inode.Destroy. -func (InodeNoopRefCount) Destroy() { +func (InodeNoopRefCount) Destroy(context.Context) { } // InodeDirectoryNoNewChildren partially implements the Inode interface. @@ -366,12 +366,12 @@ func (o *OrderedChildren) Init(opts OrderedChildrenOptions) { } // DecRef implements Inode.DecRef. -func (o *OrderedChildren) DecRef() { - o.AtomicRefCount.DecRefWithDestructor(o.Destroy) +func (o *OrderedChildren) DecRef(ctx context.Context) { + o.AtomicRefCount.DecRefWithDestructor(ctx, o.Destroy) } // Destroy cleans up resources referenced by this OrderedChildren. -func (o *OrderedChildren) Destroy() { +func (o *OrderedChildren) Destroy(context.Context) { o.mu.Lock() defer o.mu.Unlock() o.order.Reset() diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go index 46f207664..080118841 100644 --- a/pkg/sentry/fsimpl/kernfs/kernfs.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs.go @@ -116,17 +116,17 @@ func (fs *Filesystem) deferDecRef(d *vfs.Dentry) { // processDeferredDecRefs calls vfs.Dentry.DecRef on all dentries in the // droppedDentries list. See comment on Filesystem.mu. -func (fs *Filesystem) processDeferredDecRefs() { +func (fs *Filesystem) processDeferredDecRefs(ctx context.Context) { fs.mu.Lock() - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) fs.mu.Unlock() } // Precondition: fs.mu must be held for writing. -func (fs *Filesystem) processDeferredDecRefsLocked() { +func (fs *Filesystem) processDeferredDecRefsLocked(ctx context.Context) { fs.droppedDentriesMu.Lock() for _, d := range fs.droppedDentries { - d.DecRef() + d.DecRef(ctx) } fs.droppedDentries = fs.droppedDentries[:0] // Keep slice memory for reuse. fs.droppedDentriesMu.Unlock() @@ -212,16 +212,16 @@ func (d *Dentry) isSymlink() bool { } // DecRef implements vfs.DentryImpl.DecRef. -func (d *Dentry) DecRef() { - d.AtomicRefCount.DecRefWithDestructor(d.destroy) +func (d *Dentry) DecRef(ctx context.Context) { + d.AtomicRefCount.DecRefWithDestructor(ctx, d.destroy) } // Precondition: Dentry must be removed from VFS' dentry cache. -func (d *Dentry) destroy() { - d.inode.DecRef() // IncRef from Init. +func (d *Dentry) destroy(ctx context.Context) { + d.inode.DecRef(ctx) // IncRef from Init. d.inode = nil if d.parent != nil { - d.parent.DecRef() // IncRef from Dentry.InsertChild. + d.parent.DecRef(ctx) // IncRef from Dentry.InsertChild. } } @@ -230,7 +230,7 @@ func (d *Dentry) destroy() { // Although Linux technically supports inotify on pseudo filesystems (inotify // is implemented at the vfs layer), it is not particularly useful. It is left // unimplemented until someone actually needs it. -func (d *Dentry) InotifyWithParent(events, cookie uint32, et vfs.EventType) {} +func (d *Dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et vfs.EventType) {} // Watches implements vfs.DentryImpl.Watches. func (d *Dentry) Watches() *vfs.Watches { @@ -238,7 +238,7 @@ func (d *Dentry) Watches() *vfs.Watches { } // OnZeroWatches implements vfs.Dentry.OnZeroWatches. -func (d *Dentry) OnZeroWatches() {} +func (d *Dentry) OnZeroWatches(context.Context) {} // InsertChild inserts child into the vfs dentry cache with the given name under // this dentry. This does not update the directory inode, so calling this on @@ -326,12 +326,12 @@ type Inode interface { type inodeRefs interface { IncRef() - DecRef() + DecRef(ctx context.Context) TryIncRef() bool // Destroy is called when the inode reaches zero references. Destroy release // all resources (references) on objects referenced by the inode, including // any child dentries. - Destroy() + Destroy(ctx context.Context) } type inodeMetadata interface { diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_test.go b/pkg/sentry/fsimpl/kernfs/kernfs_test.go index dc407eb1d..c5d5afedf 100644 --- a/pkg/sentry/fsimpl/kernfs/kernfs_test.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs_test.go @@ -46,7 +46,7 @@ func newTestSystem(t *testing.T, rootFn RootDentryFn) *testutil.System { ctx := contexttest.Context(t) creds := auth.CredentialsFromContext(ctx) v := &vfs.VirtualFilesystem{} - if err := v.Init(); err != nil { + if err := v.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } v.MustRegisterFilesystemType("testfs", &fsType{rootFn: rootFn}, &vfs.RegisterFilesystemTypeOptions{ @@ -163,7 +163,7 @@ func (d *dir) NewDir(ctx context.Context, name string, opts vfs.MkdirOptions) (* dir := d.fs.newDir(creds, opts.Mode, nil) dirVFSD := dir.VFSDentry() if err := d.OrderedChildren.Insert(name, dirVFSD); err != nil { - dir.DecRef() + dir.DecRef(ctx) return nil, err } d.IncLinks(1) @@ -175,7 +175,7 @@ func (d *dir) NewFile(ctx context.Context, name string, opts vfs.OpenOptions) (* f := d.fs.newFile(creds, "") fVFSD := f.VFSDentry() if err := d.OrderedChildren.Insert(name, fVFSD); err != nil { - f.DecRef() + f.DecRef(ctx) return nil, err } return fVFSD, nil @@ -213,7 +213,7 @@ func TestBasic(t *testing.T) { }) }) defer sys.Destroy() - sys.GetDentryOrDie(sys.PathOpAtRoot("file1")).DecRef() + sys.GetDentryOrDie(sys.PathOpAtRoot("file1")).DecRef(sys.Ctx) } func TestMkdirGetDentry(t *testing.T) { @@ -228,7 +228,7 @@ func TestMkdirGetDentry(t *testing.T) { if err := sys.VFS.MkdirAt(sys.Ctx, sys.Creds, pop, &vfs.MkdirOptions{Mode: 0755}); err != nil { t.Fatalf("MkdirAt for PathOperation %+v failed: %v", pop, err) } - sys.GetDentryOrDie(pop).DecRef() + sys.GetDentryOrDie(pop).DecRef(sys.Ctx) } func TestReadStaticFile(t *testing.T) { @@ -246,7 +246,7 @@ func TestReadStaticFile(t *testing.T) { if err != nil { t.Fatalf("OpenAt for PathOperation %+v failed: %v", pop, err) } - defer fd.DecRef() + defer fd.DecRef(sys.Ctx) content, err := sys.ReadToEnd(fd) if err != nil { @@ -273,7 +273,7 @@ func TestCreateNewFileInStaticDir(t *testing.T) { } // Close the file. The file should persist. - fd.DecRef() + fd.DecRef(sys.Ctx) fd, err = sys.VFS.OpenAt(sys.Ctx, sys.Creds, pop, &vfs.OpenOptions{ Flags: linux.O_RDONLY, @@ -281,7 +281,7 @@ func TestCreateNewFileInStaticDir(t *testing.T) { if err != nil { t.Fatalf("OpenAt(pop:%+v) = %+v failed: %v", pop, fd, err) } - fd.DecRef() + fd.DecRef(sys.Ctx) } func TestDirFDReadWrite(t *testing.T) { @@ -297,7 +297,7 @@ func TestDirFDReadWrite(t *testing.T) { if err != nil { t.Fatalf("OpenAt for PathOperation %+v failed: %v", pop, err) } - defer fd.DecRef() + defer fd.DecRef(sys.Ctx) // Read/Write should fail for directory FDs. if _, err := fd.Read(sys.Ctx, usermem.BytesIOSequence([]byte{}), vfs.ReadOptions{}); err != syserror.EISDIR { -- cgit v1.2.3