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authorgVisor bot <gvisor-bot@google.com>2020-06-10 01:50:13 +0000
committergVisor bot <gvisor-bot@google.com>2020-06-10 01:50:13 +0000
commitbc94fb247aa7868a5a41507ea7a17e1fc79473fe (patch)
tree095b7b53ddea4d4e73c3be78a09908a17b06e90e /pkg/sentry/fs
parent3cdc796936d39c0c2173d371f97c084c94f8d2a4 (diff)
parent67565078bbcdd8f797206d996605df8f6658d00a (diff)
Merge release-20200522.0-112-g67565078b (automated)
Diffstat (limited to 'pkg/sentry/fs')
-rw-r--r--pkg/sentry/fs/file.go2
-rw-r--r--pkg/sentry/fs/lock/lock.go41
-rw-r--r--pkg/sentry/fs/lock/lock_set_functions.go8
-rw-r--r--pkg/sentry/fs/lock/lock_state_autogen.go2
4 files changed, 17 insertions, 36 deletions
diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go
index 2a278fbe3..ca41520b4 100644
--- a/pkg/sentry/fs/file.go
+++ b/pkg/sentry/fs/file.go
@@ -146,7 +146,7 @@ func (f *File) DecRef() {
f.DecRefWithDestructor(func() {
// Drop BSD style locks.
lockRng := lock.LockRange{Start: 0, End: lock.LockEOF}
- f.Dirent.Inode.LockCtx.BSD.UnlockRegion(lock.UniqueID(f.UniqueID), lockRng)
+ f.Dirent.Inode.LockCtx.BSD.UnlockRegion(f, lockRng)
// Release resources held by the FileOperations.
f.FileOperations.Release()
diff --git a/pkg/sentry/fs/lock/lock.go b/pkg/sentry/fs/lock/lock.go
index 926538d90..8a5d9c7eb 100644
--- a/pkg/sentry/fs/lock/lock.go
+++ b/pkg/sentry/fs/lock/lock.go
@@ -62,7 +62,7 @@ import (
type LockType int
// UniqueID is a unique identifier of the holder of a regional file lock.
-type UniqueID uint64
+type UniqueID interface{}
const (
// ReadLock describes a POSIX regional file lock to be taken
@@ -98,12 +98,7 @@ type Lock struct {
// If len(Readers) > 0 then HasWriter must be false.
Readers map[UniqueID]bool
- // HasWriter indicates that this is a write lock held by a single
- // UniqueID.
- HasWriter bool
-
- // Writer is only valid if HasWriter is true. It identifies a
- // single write lock holder.
+ // Writer holds the writer unique ID. It's nil if there are no writers.
Writer UniqueID
}
@@ -186,7 +181,6 @@ func makeLock(uid UniqueID, t LockType) Lock {
case ReadLock:
value.Readers[uid] = true
case WriteLock:
- value.HasWriter = true
value.Writer = uid
default:
panic(fmt.Sprintf("makeLock: invalid lock type %d", t))
@@ -196,10 +190,7 @@ func makeLock(uid UniqueID, t LockType) Lock {
// isHeld returns true if uid is a holder of Lock.
func (l Lock) isHeld(uid UniqueID) bool {
- if l.HasWriter && l.Writer == uid {
- return true
- }
- return l.Readers[uid]
+ return l.Writer == uid || l.Readers[uid]
}
// lock sets uid as a holder of a typed lock on Lock.
@@ -214,20 +205,20 @@ func (l *Lock) lock(uid UniqueID, t LockType) {
}
// We cannot downgrade a write lock to a read lock unless the
// uid is the same.
- if l.HasWriter {
+ if l.Writer != nil {
if l.Writer != uid {
panic(fmt.Sprintf("lock: cannot downgrade write lock to read lock for uid %d, writer is %d", uid, l.Writer))
}
// Ensure that there is only one reader if upgrading.
l.Readers = make(map[UniqueID]bool)
// Ensure that there is no longer a writer.
- l.HasWriter = false
+ l.Writer = nil
}
l.Readers[uid] = true
return
case WriteLock:
// If we are already the writer, then this is a no-op.
- if l.HasWriter && l.Writer == uid {
+ if l.Writer == uid {
return
}
// We can only upgrade a read lock to a write lock if there
@@ -243,7 +234,6 @@ func (l *Lock) lock(uid UniqueID, t LockType) {
}
// Ensure that there is only a writer.
l.Readers = make(map[UniqueID]bool)
- l.HasWriter = true
l.Writer = uid
default:
panic(fmt.Sprintf("lock: invalid lock type %d", t))
@@ -277,9 +267,8 @@ func (l LockSet) canLock(uid UniqueID, t LockType, r LockRange) bool {
switch t {
case ReadLock:
return l.lockable(r, func(value Lock) bool {
- // If there is no writer, there's no problem adding
- // another reader.
- if !value.HasWriter {
+ // If there is no writer, there's no problem adding another reader.
+ if value.Writer == nil {
return true
}
// If there is a writer, then it must be the same uid
@@ -289,10 +278,9 @@ func (l LockSet) canLock(uid UniqueID, t LockType, r LockRange) bool {
case WriteLock:
return l.lockable(r, func(value Lock) bool {
// If there are only readers.
- if !value.HasWriter {
- // Then this uid can only take a write lock if
- // this is a private upgrade, meaning that the
- // only reader is uid.
+ if value.Writer == nil {
+ // Then this uid can only take a write lock if this is a private
+ // upgrade, meaning that the only reader is uid.
return len(value.Readers) == 1 && value.Readers[uid]
}
// If the uid is already a writer on this region, then
@@ -304,7 +292,8 @@ func (l LockSet) canLock(uid UniqueID, t LockType, r LockRange) bool {
}
}
-// lock returns true if uid took a lock of type t on the entire range of LockRange.
+// lock returns true if uid took a lock of type t on the entire range of
+// LockRange.
//
// Preconditions: r.Start <= r.End (will panic otherwise).
func (l *LockSet) lock(uid UniqueID, t LockType, r LockRange) bool {
@@ -339,7 +328,7 @@ func (l *LockSet) lock(uid UniqueID, t LockType, r LockRange) bool {
seg, _ = l.SplitUnchecked(seg, r.End)
}
- // Set the lock on the segment. This is guaranteed to
+ // Set the lock on the segment. This is guaranteed to
// always be safe, given canLock above.
value := seg.ValuePtr()
value.lock(uid, t)
@@ -386,7 +375,7 @@ func (l *LockSet) unlock(uid UniqueID, r LockRange) {
value := seg.Value()
var remove bool
- if value.HasWriter && value.Writer == uid {
+ if value.Writer == uid {
// If we are unlocking a writer, then since there can
// only ever be one writer and no readers, then this
// lock should always be removed from the set.
diff --git a/pkg/sentry/fs/lock/lock_set_functions.go b/pkg/sentry/fs/lock/lock_set_functions.go
index 8a3ace0c1..50a16e662 100644
--- a/pkg/sentry/fs/lock/lock_set_functions.go
+++ b/pkg/sentry/fs/lock/lock_set_functions.go
@@ -44,14 +44,9 @@ func (lockSetFunctions) Merge(r1 LockRange, val1 Lock, r2 LockRange, val2 Lock)
return Lock{}, false
}
}
- if val1.HasWriter != val2.HasWriter {
+ if val1.Writer != val2.Writer {
return Lock{}, false
}
- if val1.HasWriter {
- if val1.Writer != val2.Writer {
- return Lock{}, false
- }
- }
return val1, true
}
@@ -62,7 +57,6 @@ func (lockSetFunctions) Split(r LockRange, val Lock, split uint64) (Lock, Lock)
for k, v := range val.Readers {
val0.Readers[k] = v
}
- val0.HasWriter = val.HasWriter
val0.Writer = val.Writer
return val, val0
diff --git a/pkg/sentry/fs/lock/lock_state_autogen.go b/pkg/sentry/fs/lock/lock_state_autogen.go
index d5ea98366..59c493fcb 100644
--- a/pkg/sentry/fs/lock/lock_state_autogen.go
+++ b/pkg/sentry/fs/lock/lock_state_autogen.go
@@ -10,14 +10,12 @@ func (x *Lock) beforeSave() {}
func (x *Lock) save(m state.Map) {
x.beforeSave()
m.Save("Readers", &x.Readers)
- m.Save("HasWriter", &x.HasWriter)
m.Save("Writer", &x.Writer)
}
func (x *Lock) afterLoad() {}
func (x *Lock) load(m state.Map) {
m.Load("Readers", &x.Readers)
- m.Load("HasWriter", &x.HasWriter)
m.Load("Writer", &x.Writer)
}