From 217c516c1ba2634560ccba50a246aeea7d097f29 Mon Sep 17 00:00:00 2001
From: Nickolai Zeldovich <kolya@mit.edu>
Date: Thu, 14 Nov 2002 21:24:30 +0000
Subject: [PATCH] A better way to do cross-cell-only fakestat, which should
 also avoid problems with Linux's attribute validation.

(cherry picked from commit 2d182a7fc1aa17bce1f63164944995663f567c12)
---
 src/afs/LINUX/osi_vnodeops.c    | 20 +++++--------
 src/afs/VNOPS/afs_vnop_lookup.c | 50 ++++++++++++++++-----------------
 2 files changed, 32 insertions(+), 38 deletions(-)

diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index 30a2eaf47..e58af0ac7 100644
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -675,19 +675,14 @@ static int afs_linux_revalidate(struct dentry *dp)
     struct vrequest treq;
     struct vcache *vcp = ITOAFS(dp->d_inode);
     struct vcache *rootvp = NULL;
-    struct afs_fakestat_state fakestat;
 
     AFS_GLOCK();
 
-    afs_InitFakeStat(&fakestat);
-    if (vcp->mvstat == 1) {
-      afs_InitReq(&treq, credp);
-      rootvp = vcp;
-      code = afs_TryEvalFakeStat(&rootvp, &fakestat, &treq);
-      if (code) {
-	AFS_GUNLOCK();
-	return -code;
-      }
+    if (afs_fakestat_enable && vcp->mvstat == 1 && vcp->mvid &&
+	(vcp->states & CMValid) && (vcp->states & CStatd)) {
+	ObtainSharedLock(&afs_xvcache, 680);
+	rootvp = afs_FindVCache(vcp->mvid, 0, 0, 0, 0);
+	ReleaseSharedLock(&afs_xvcache);
     }
 
 #ifdef AFS_LINUX24_ENV
@@ -698,14 +693,14 @@ static int afs_linux_revalidate(struct dentry *dp)
     if (vcp->states & CStatd) {
 	if (*dp->d_name.name != '/' && vcp->mvstat == 2) /* root vnode */
 	    check_bad_parent(dp); /* check and correct mvid */
-	if (rootvp && rootvp != vcp)
+	if (rootvp)
 	    vcache2fakeinode(rootvp, vcp);
 	else
 	    vcache2inode(vcp);
 #ifdef AFS_LINUX24_ENV
 	unlock_kernel();
 #endif
-	afs_PutFakeStat(&fakestat);
+	if (rootvp) afs_PutVCache(rootvp);
 	AFS_GUNLOCK();
 	return 0;
     }
@@ -718,7 +713,6 @@ static int afs_linux_revalidate(struct dentry *dp)
 #ifdef AFS_LINUX24_ENV
     unlock_kernel();
 #endif
-    afs_PutFakeStat(&fakestat);
     AFS_GUNLOCK();
     crfree(credp);
 
diff --git a/src/afs/VNOPS/afs_vnop_lookup.c b/src/afs/VNOPS/afs_vnop_lookup.c
index 0a57b58a8..0c393fb32 100644
--- a/src/afs/VNOPS/afs_vnop_lookup.c
+++ b/src/afs/VNOPS/afs_vnop_lookup.c
@@ -54,7 +54,7 @@ extern struct inode_operations afs_symlink_iops, afs_dir_iops;
 
 afs_int32 afs_bulkStatsDone;
 static int bulkStatCounter = 0;	/* counter for bulk stat seq. numbers */
-int afs_fakestat_enable = 0;
+int afs_fakestat_enable = 0;	/* 1: fakestat-all, 2: fakestat-crosscell */
 
 
 /* this would be faster if it did comparison as int32word, but would be 
@@ -265,9 +265,11 @@ afs_InitFakeStat(state)
  *
  * The actual implementation of afs_EvalFakeStat and afs_TryEvalFakeStat,
  * which is called by those wrapper functions.
+ *
+ * Only issues RPCs if canblock is non-zero.
  */
-static int afs_EvalFakeStat_int(stricr vcache **avcp,
-      struct afs_fakestat_state *state, struct vrequest *areq, int canblock)
+int afs_EvalFakeStat_int(struct vcache **avcp, struct afs_fakestat_state *state,
+	struct vrequest *areq, int canblock)
 {
     struct vcache *tvc, *root_vp;
     struct volume *tvolp = NULL;
@@ -282,29 +284,10 @@ static int afs_EvalFakeStat_int(stricr vcache **avcp,
     if (tvc->mvstat != 1)
 	return 0;
 
+    /* Is the call to VerifyVCache really necessary? */
     code = afs_VerifyVCache(tvc, areq);
     if (code)
 	goto done;
-
-    if (afs_fakestat_enable == 2 && !canblock) {
-	ObtainSharedLock(&tvc->lock, 680);
-	if (!tvc->linkData) {
-	    UpgradeSToWLock(&tvc->lock, 681);
-	    code = afs_HandleLink(tvc, areq);
-	    if (code) {
-		ReleaseWriteLock(&tvc->lock);
-		goto done;
-	    }
-	    ConvertWToRLock(&tvc->lock);
-	} else {
-	    ConvertSToRLock(&tvc->lock);
-	}
-
-	if (!afs_strchr(tvc->linkData, ':'))
-	    canblock = 1;
-	ReleaseReadLock(&tvc->lock);
-    }
-
     if (canblock) {
 	ObtainWriteLock(&tvc->lock, 599);
 	code = EvalMountPoint(tvc, NULL, &tvolp, areq);
@@ -1413,17 +1396,34 @@ afs_lookup(adp, aname, avcp, acred)
     } /* sub-block just to reduce stack usage */
 
     if (tvc) {
-       if (adp->states & CForeign)
+	int force_eval = afs_fakestat_enable ? 0 : 1;
+
+	if (adp->states & CForeign)
 	   tvc->states |= CForeign;
 	tvc->parentVnode = adp->fid.Fid.Vnode;
 	tvc->parentUnique = adp->fid.Fid.Unique;
 	tvc->states &= ~CBulkStat;
 
+	if (afs_fakestat_enable == 2 && tvc->mvstat == 1) {
+	    ObtainSharedLock(&tvc->lock, 680);
+	    if (!tvc->linkData) {
+		UpgradeSToWLock(&tvc->lock, 681);
+		code = afs_HandleLink(tvc, &treq);
+		ConvertWToRLock(&tvc->lock);
+	    } else {
+		ConvertSToRLock(&tvc->lock);
+		code = 0;
+	    }
+	    if (!code && !strchr(tvc->linkData, ':'))
+		force_eval = 1;
+	    ReleaseReadLock(&tvc->lock);
+	}
+
 #if defined(UKERNEL) && defined(AFS_WEB_ENHANCEMENTS)
         if (!(flags & AFS_LOOKUP_NOEVAL))
           /* don't eval mount points */
 #endif /* UKERNEL && AFS_WEB_ENHANCEMENTS */
-	if (!afs_fakestat_enable && tvc->mvstat == 1) {
+	if (tvc->mvstat == 1 && force_eval) {
 	    /* a mt point, possibly unevaluated */
 	    struct volume *tvolp;
 
-- 
2.39.5