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-rw-r--r--pkg/abi/linux/linux_abi_autogen_unsafe.go14
-rw-r--r--pkg/refs/refcounter.go7
-rw-r--r--pkg/sentry/fsimpl/tmpfs/inode_refs.go112
-rw-r--r--pkg/sentry/fsimpl/tmpfs/tmpfs.go27
-rw-r--r--pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go24
5 files changed, 28 insertions, 156 deletions
diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go
index 1456b1fde..3cc56623f 100644
--- a/pkg/abi/linux/linux_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go
@@ -150,7 +150,7 @@ func (s *Statx) Packed() bool {
// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
func (s *Statx) MarshalUnsafe(dst []byte) {
- if s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
+ if s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
safecopy.CopyIn(dst, unsafe.Pointer(s))
} else {
// Type Statx doesn't have a packed layout in memory, fallback to MarshalBytes.
@@ -171,7 +171,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) {
// CopyOutN implements marshal.Marshallable.CopyOutN.
//go:nosplit
func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
- if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
+ if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
// Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
s.MarshalBytes(buf) // escapes: fallback.
@@ -227,7 +227,7 @@ func (s *Statx) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
// WriteTo implements io.WriterTo.WriteTo.
func (s *Statx) WriteTo(w io.Writer) (int64, error) {
- if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
+ if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
// Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := make([]byte, s.SizeBytes())
s.MarshalBytes(buf)
@@ -1833,7 +1833,7 @@ func (i *IPTIP) MarshalUnsafe(dst []byte) {
// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
func (i *IPTIP) UnmarshalUnsafe(src []byte) {
- if i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+ if i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
safecopy.CopyOut(unsafe.Pointer(i), src)
} else {
// Type IPTIP doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -1844,7 +1844,7 @@ func (i *IPTIP) UnmarshalUnsafe(src []byte) {
// CopyOutN implements marshal.Marshallable.CopyOutN.
//go:nosplit
func (i *IPTIP) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
- if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
+ if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
// Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
i.MarshalBytes(buf) // escapes: fallback.
@@ -1874,7 +1874,7 @@ func (i *IPTIP) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
// CopyIn implements marshal.Marshallable.CopyIn.
//go:nosplit
func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
- if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+ if !i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
// Type IPTIP doesn't have a packed layout in memory, fall back to UnmarshalBytes.
buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -1900,7 +1900,7 @@ func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
// WriteTo implements io.WriterTo.WriteTo.
func (i *IPTIP) WriteTo(w io.Writer) (int64, error) {
- if !i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
+ if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
// Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := make([]byte, i.SizeBytes())
i.MarshalBytes(buf)
diff --git a/pkg/refs/refcounter.go b/pkg/refs/refcounter.go
index 3f39edb66..61790221b 100644
--- a/pkg/refs/refcounter.go
+++ b/pkg/refs/refcounter.go
@@ -215,8 +215,6 @@ type AtomicRefCount struct {
// LeakMode configures the leak checker.
type LeakMode uint32
-// TODO(gvisor.dev/issue/1624): Simplify down to two modes once vfs1 ref
-// counting is gone.
const (
// UninitializedLeakChecking indicates that the leak checker has not yet been initialized.
UninitializedLeakChecking LeakMode = iota
@@ -246,11 +244,6 @@ func SetLeakMode(mode LeakMode) {
atomic.StoreUint32(&leakMode, uint32(mode))
}
-// GetLeakMode returns the current leak mode.
-func GetLeakMode() LeakMode {
- return LeakMode(atomic.LoadUint32(&leakMode))
-}
-
const maxStackFrames = 40
type fileLine struct {
diff --git a/pkg/sentry/fsimpl/tmpfs/inode_refs.go b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
deleted file mode 100644
index 3d3f6ff11..000000000
--- a/pkg/sentry/fsimpl/tmpfs/inode_refs.go
+++ /dev/null
@@ -1,112 +0,0 @@
-package tmpfs
-
-import (
- "sync/atomic"
-
- "gvisor.dev/gvisor/pkg/log"
- refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
- "runtime"
-)
-
-// ownerType is used to customize logging. Note that we use a pointer to T so
-// that we do not copy the entire object when passed as a format parameter.
-var inodeownerType *inode
-
-// Refs implements refs.RefCounter. It keeps a reference count using atomic
-// operations and calls the destructor when the count reaches zero.
-//
-// Note that the number of references is actually refCount + 1 so that a default
-// zero-value Refs object contains one reference.
-//
-// +stateify savable
-type inodeRefs struct {
- // refCount is composed of two fields:
- //
- // [32-bit speculative references]:[32-bit real references]
- //
- // Speculative references are used for TryIncRef, to avoid a CompareAndSwap
- // loop. See IncRef, DecRef and TryIncRef for details of how these fields are
- // used.
- refCount int64
-}
-
-func (r *inodeRefs) finalize() {
- var note string
- switch refs_vfs1.GetLeakMode() {
- case refs_vfs1.NoLeakChecking:
- return
- case refs_vfs1.UninitializedLeakChecking:
- note = "(Leak checker uninitialized): "
- }
- if n := r.ReadRefs(); n != 0 {
- log.Warningf("%sAtomicRefCount %p owned by %T garbage collected with ref count of %d (want 0)", note, r, inodeownerType, n)
- }
-}
-
-// EnableLeakCheck checks for reference leaks when Refs gets garbage collected.
-func (r *inodeRefs) EnableLeakCheck() {
- if refs_vfs1.GetLeakMode() != refs_vfs1.NoLeakChecking {
- runtime.SetFinalizer(r, (*inodeRefs).finalize)
- }
-}
-
-// ReadRefs returns the current number of references. The returned count is
-// inherently racy and is unsafe to use without external synchronization.
-func (r *inodeRefs) ReadRefs() int64 {
-
- return atomic.LoadInt64(&r.refCount) + 1
-}
-
-// IncRef implements refs.RefCounter.IncRef.
-//
-//go:nosplit
-func (r *inodeRefs) IncRef() {
- if v := atomic.AddInt64(&r.refCount, 1); v <= 0 {
- panic("Incrementing non-positive ref count")
- }
-}
-
-// TryIncRef implements refs.RefCounter.TryIncRef.
-//
-// To do this safely without a loop, a speculative reference is first acquired
-// on the object. This allows multiple concurrent TryIncRef calls to distinguish
-// other TryIncRef calls from genuine references held.
-//
-//go:nosplit
-func (r *inodeRefs) TryIncRef() bool {
- const speculativeRef = 1 << 32
- v := atomic.AddInt64(&r.refCount, speculativeRef)
- if int32(v) < 0 {
-
- atomic.AddInt64(&r.refCount, -speculativeRef)
- return false
- }
-
- atomic.AddInt64(&r.refCount, -speculativeRef+1)
- return true
-}
-
-// DecRef implements refs.RefCounter.DecRef.
-//
-// Note that speculative references are counted here. Since they were added
-// prior to real references reaching zero, they will successfully convert to
-// real references. In other words, we see speculative references only in the
-// following case:
-//
-// A: TryIncRef [speculative increase => sees non-negative references]
-// B: DecRef [real decrease]
-// A: TryIncRef [transform speculative to real]
-//
-//go:nosplit
-func (r *inodeRefs) DecRef(destroy func()) {
- switch v := atomic.AddInt64(&r.refCount, -1); {
- case v < -1:
- panic("Decrementing non-positive ref count")
-
- case v == -1:
-
- if destroy != nil {
- destroy()
- }
- }
-}
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index 5640380dc..68e615e8b 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -285,10 +285,13 @@ type inode struct {
// fs is the owning filesystem. fs is immutable.
fs *filesystem
+ // refs is a reference count. refs is accessed using atomic memory
+ // operations.
+ //
// A reference is held on all inodes as long as they are reachable in the
// filesystem tree, i.e. nlink is nonzero. This reference is dropped when
// nlink reaches 0.
- refs inodeRefs
+ refs int64
// xattrs implements extended attributes.
//
@@ -324,6 +327,7 @@ func (i *inode) init(impl interface{}, fs *filesystem, kuid auth.KUID, kgid auth
panic("file type is required in FileMode")
}
i.fs = fs
+ i.refs = 1
i.mode = uint32(mode)
i.uid = uint32(kuid)
i.gid = uint32(kgid)
@@ -335,7 +339,6 @@ func (i *inode) init(impl interface{}, fs *filesystem, kuid auth.KUID, kgid auth
i.mtime = now
// i.nlink initialized by caller
i.impl = impl
- i.refs.EnableLeakCheck()
}
// incLinksLocked increments i's link count.
@@ -366,15 +369,25 @@ func (i *inode) decLinksLocked(ctx context.Context) {
}
func (i *inode) incRef() {
- i.refs.IncRef()
+ if atomic.AddInt64(&i.refs, 1) <= 1 {
+ panic("tmpfs.inode.incRef() called without holding a reference")
+ }
}
func (i *inode) tryIncRef() bool {
- return i.refs.TryIncRef()
+ for {
+ refs := atomic.LoadInt64(&i.refs)
+ if refs == 0 {
+ return false
+ }
+ if atomic.CompareAndSwapInt64(&i.refs, refs, refs+1) {
+ return true
+ }
+ }
}
func (i *inode) decRef(ctx context.Context) {
- i.refs.DecRef(func() {
+ if refs := atomic.AddInt64(&i.refs, -1); refs == 0 {
i.watches.HandleDeletion(ctx)
if regFile, ok := i.impl.(*regularFile); ok {
// Release memory used by regFile to store data. Since regFile is
@@ -382,7 +395,9 @@ func (i *inode) decRef(ctx context.Context) {
// metadata.
regFile.data.DropAll(regFile.memFile)
}
- })
+ } else if refs < 0 {
+ panic("tmpfs.inode.decRef() called without holding a reference")
+ }
}
func (i *inode) checkPermissions(creds *auth.Credentials, ats vfs.AccessTypes) error {
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go b/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
index d88136656..1b617bd35 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
@@ -58,31 +58,7 @@ func (x *dentryEntry) StateLoad(m state.Source) {
m.Load(1, &x.prev)
}
-func (x *inodeRefs) StateTypeName() string {
- return "pkg/sentry/fsimpl/tmpfs.inodeRefs"
-}
-
-func (x *inodeRefs) StateFields() []string {
- return []string{
- "refCount",
- }
-}
-
-func (x *inodeRefs) beforeSave() {}
-
-func (x *inodeRefs) StateSave(m state.Sink) {
- x.beforeSave()
- m.Save(0, &x.refCount)
-}
-
-func (x *inodeRefs) afterLoad() {}
-
-func (x *inodeRefs) StateLoad(m state.Source) {
- m.Load(0, &x.refCount)
-}
-
func init() {
state.Register((*dentryList)(nil))
state.Register((*dentryEntry)(nil))
- state.Register((*inodeRefs)(nil))
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 13:26:03 +0000