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-rw-r--r--pkg/sentry/fsimpl/gofer/gofer.go20
-rw-r--r--pkg/sentry/platform/ring0/defs_impl_arm64.go3
2 files changed, 17 insertions, 6 deletions
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index 4ac8dd81d..63e589859 100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -1158,7 +1158,8 @@ func (d *dentry) OnZeroWatches(ctx context.Context) {
// operation. One of the calls may destroy the dentry, so subsequent calls will
// do nothing.
//
-// Preconditions: d.fs.renameMu must be locked for writing.
+// Preconditions: d.fs.renameMu must be locked for writing; it may be
+// temporarily unlocked.
func (d *dentry) checkCachingLocked(ctx context.Context) {
// Dentries with a non-zero reference count must be retained. (The only way
// to obtain a reference on a dentry with zero references is via path
@@ -1238,11 +1239,13 @@ func (d *dentry) checkCachingLocked(ctx context.Context) {
}
}
-// destroyLocked destroys the dentry. It may flushes dirty pages from cache,
-// close p9 file and remove reference on parent dentry.
+// destroyLocked destroys the dentry.
//
-// Preconditions: d.fs.renameMu must be locked for writing. d.refs == 0. d is
-// not a child dentry.
+// Preconditions:
+// * d.fs.renameMu must be locked for writing; it may be temporarily unlocked.
+// * d.refs == 0.
+// * d.parent.children[d.name] != d, i.e. d is not reachable by path traversal
+// from its former parent dentry.
func (d *dentry) destroyLocked(ctx context.Context) {
switch atomic.LoadInt64(&d.refs) {
case 0:
@@ -1254,6 +1257,10 @@ func (d *dentry) destroyLocked(ctx context.Context) {
panic("dentry.destroyLocked() called with references on the dentry")
}
+ // Allow the following to proceed without renameMu locked to improve
+ // scalability.
+ d.fs.renameMu.Unlock()
+
mf := d.fs.mfp.MemoryFile()
d.handleMu.Lock()
d.dataMu.Lock()
@@ -1315,6 +1322,9 @@ func (d *dentry) destroyLocked(ctx context.Context) {
delete(d.fs.syncableDentries, d)
d.fs.syncMu.Unlock()
}
+
+ d.fs.renameMu.Lock()
+
// Drop the reference held by d on its parent without recursively locking
// d.fs.renameMu.
if d.parent != nil {
diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index 9fb351879..424b66f76 100644
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -1,9 +1,10 @@
package ring0
import (
- "fmt"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
+
+ "fmt"
"gvisor.dev/gvisor/pkg/usermem"
"io"
"reflect"