Complete vfs2 implementation of fallocate.

This change includes overlay, special regular gofer files, and hostfs.

Fixes #3589.

PiperOrigin-RevId: 332330860

1 files changed, 5 insertions, 22 deletions

diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go
index a2e9342d5..24f03ee94 100644
--- a/pkg/sentry/fsimpl/gofer/regular_file.go
+++ b/pkg/sentry/fsimpl/gofer/regular_file.go
@@ -79,28 +79,11 @@ func (fd *regularFileFD) OnClose(ctx context.Context) error {
 // Allocate implements vfs.FileDescriptionImpl.Allocate.
 func (fd *regularFileFD) Allocate(ctx context.Context, mode, offset, length uint64) error {
 	d := fd.dentry()
-	d.metadataMu.Lock()
-	defer d.metadataMu.Unlock()
-
-	// Allocating a smaller size is a noop.
-	size := offset + length
-	if d.cachedMetadataAuthoritative() && size <= d.size {
-		return nil
-	}
-
-	d.handleMu.RLock()
-	err := d.writeFile.allocate(ctx, p9.ToAllocateMode(mode), offset, length)
-	d.handleMu.RUnlock()
-	if err != nil {
-		return err
-	}
-	d.dataMu.Lock()
-	atomic.StoreUint64(&d.size, size)
-	d.dataMu.Unlock()
-	if d.cachedMetadataAuthoritative() {
-		d.touchCMtimeLocked()
-	}
-	return nil
+	return d.doAllocate(ctx, offset, length, func() error {
+		d.handleMu.RLock()
+		defer d.handleMu.RUnlock()
+		return d.writeFile.allocate(ctx, p9.ToAllocateMode(mode), offset, length)
+	})
 }
 
 // PRead implements vfs.FileDescriptionImpl.PRead.