[lisa] Implement lisafs protocol methods in VFS2 gofer client and fsgofer.

Introduces RPC methods in lisafs. Makes that gofer client use lisafs RPCs
instead of p9 when lisafs is enabled.

Implements the handlers for those methods in fsgofer.

Fixes #5465

PiperOrigin-RevId: 398080310

1 files changed, 41 insertions, 9 deletions

diff --git a/pkg/sentry/fsimpl/gofer/revalidate.go b/pkg/sentry/fsimpl/gofer/revalidate.go
index 226790a11..5d4009832 100644
--- a/pkg/sentry/fsimpl/gofer/revalidate.go
+++ b/pkg/sentry/fsimpl/gofer/revalidate.go
@@ -15,7 +15,9 @@
 package gofer
 
 import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/p9"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/sync"
 )
@@ -234,28 +236,54 @@ func (fs *filesystem) revalidateHelper(ctx context.Context, vfsObj *vfs.VirtualF
 	}
 	// Lock metadata on all dentries *before* getting attributes for them.
 	state.lockAllMetadata()
-	stats, err := state.start.file.multiGetAttr(ctx, state.names)
-	if err != nil {
-		return err
+
+	var (
+		stats     []p9.FullStat
+		statsLisa []linux.Statx
+		numStats  int
+	)
+	if fs.opts.lisaEnabled {
+		var err error
+		statsLisa, err = state.start.controlFDLisa.WalkStat(ctx, state.names)
+		if err != nil {
+			return err
+		}
+		numStats = len(statsLisa)
+	} else {
+		var err error
+		stats, err = state.start.file.multiGetAttr(ctx, state.names)
+		if err != nil {
+			return err
+		}
+		numStats = len(stats)
 	}
 
 	i := -1
 	for d := state.popFront(); d != nil; d = state.popFront() {
 		i++
-		found := i < len(stats)
+		found := i < numStats
 		if i == 0 && len(state.names[0]) == 0 {
 			if found && !d.isSynthetic() {
 				// First dentry is where the search is starting, just update attributes
 				// since it cannot be replaced.
-				d.updateFromP9AttrsLocked(stats[i].Valid, &stats[i].Attr) // +checklocksforce: acquired by lockAllMetadata.
+				if fs.opts.lisaEnabled {
+					d.updateFromLisaStatLocked(&statsLisa[i]) // +checklocksforce: acquired by lockAllMetadata.
+				} else {
+					d.updateFromP9AttrsLocked(stats[i].Valid, &stats[i].Attr) // +checklocksforce: acquired by lockAllMetadata.
+				}
 			}
 			d.metadataMu.Unlock() // +checklocksforce: see above.
 			continue
 		}
 
-		// Note that synthetic dentries will always fails the comparison check
-		// below.
-		if !found || d.qidPath != stats[i].QID.Path {
+		// Note that synthetic dentries will always fail this comparison check.
+		var shouldInvalidate bool
+		if fs.opts.lisaEnabled {
+			shouldInvalidate = !found || d.inoKey != inoKeyFromStat(&statsLisa[i])
+		} else {
+			shouldInvalidate = !found || d.qidPath != stats[i].QID.Path
+		}
+		if shouldInvalidate {
 			d.metadataMu.Unlock() // +checklocksforce: see above.
 			if !found && d.isSynthetic() {
 				// We have a synthetic file, and no remote file has arisen to replace
@@ -298,7 +326,11 @@ func (fs *filesystem) revalidateHelper(ctx context.Context, vfsObj *vfs.VirtualF
 		}
 
 		// The file at this path hasn't changed. Just update cached metadata.
-		d.updateFromP9AttrsLocked(stats[i].Valid, &stats[i].Attr) // +checklocksforce: see above.
+		if fs.opts.lisaEnabled {
+			d.updateFromLisaStatLocked(&statsLisa[i]) // +checklocksforce: see above.
+		} else {
+			d.updateFromP9AttrsLocked(stats[i].Valid, &stats[i].Attr) // +checklocksforce: see above.
+		}
 		d.metadataMu.Unlock()
 	}