svn commit: r363882 - head/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Wed Aug  5 07:30:17 2020
New Revision: 363882
URL: https://svnweb.freebsd.org/changeset/base/363882

Log:
  cache: stop messing with cn_flags
  
  This removes flag setting/unsetting carried over from regular lookup.
  Flags still get for compatibility when falling back.
  
  Note .. and . handling can get partially folded together.

Modified:
  head/sys/kern/vfs_cache.c

Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c	Wed Aug  5 07:28:51 2020	(r363881)
+++ head/sys/kern/vfs_cache.c	Wed Aug  5 07:30:17 2020	(r363882)
@@ -3098,7 +3098,30 @@ cache_fpl_handled_impl(struct cache_fpl *fpl, int erro
 	(LOCKLEAF | LOCKPARENT | WANTPARENT | FOLLOW | LOCKSHARED | SAVENAME | \
 	 ISOPEN | NOMACCHECK | AUDITVNODE1 | AUDITVNODE2)
 
+#define CACHE_FPL_INTERNAL_CN_FLAGS \
+	(ISDOTDOT | MAKEENTRY | ISLASTCN)
+
+_Static_assert((CACHE_FPL_SUPPORTED_CN_FLAGS & CACHE_FPL_INTERNAL_CN_FLAGS) == 0,
+    "supported and internal flags overlap");
+
 static bool
+cache_fpl_islastcn(struct nameidata *ndp)
+{
+
+	return (*ndp->ni_next == 0);
+}
+
+static bool
+cache_fpl_isdotdot(struct componentname *cnp)
+{
+
+	if (cnp->cn_namelen == 2 &&
+	    cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
+		return (true);
+	return (false);
+}
+
+static bool
 cache_can_fplookup(struct cache_fpl *fpl)
 {
 	struct nameidata *ndp;
@@ -3253,15 +3276,17 @@ out_abort:
 /*
  * The target vnode is not supported, prepare for the slow path to take over.
  */
-static int
+static int __noinline
 cache_fplookup_partial_setup(struct cache_fpl *fpl)
 {
+	struct nameidata *ndp;
 	struct componentname *cnp;
 	enum vgetstate dvs;
 	struct vnode *dvp;
 	struct pwd *pwd;
 	seqc_t dvp_seqc;
 
+	ndp = fpl->ndp;
 	cnp = fpl->cnp;
 	dvp = fpl->dvp;
 	dvp_seqc = fpl->dvp_seqc;
@@ -3287,8 +3312,15 @@ cache_fplookup_partial_setup(struct cache_fpl *fpl)
 		return (cache_fpl_aborted(fpl));
 	}
 
-	fpl->ndp->ni_startdir = dvp;
+	cache_fpl_restore(fpl, &fpl->snd);
 
+	ndp->ni_startdir = dvp;
+	cnp->cn_flags |= MAKEENTRY;
+	if (cache_fpl_islastcn(ndp))
+		cnp->cn_flags |= ISLASTCN;
+	if (cache_fpl_isdotdot(cnp))
+		cnp->cn_flags |= ISDOTDOT;
+
 	return (0);
 }
 
@@ -3763,18 +3795,6 @@ cache_fplookup_parse(struct cache_fpl *fpl)
 	}
 	ndp->ni_next = cp;
 
-	cnp->cn_flags |= MAKEENTRY;
-
-	if (cnp->cn_namelen == 2 &&
-	    cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
-		cnp->cn_flags |= ISDOTDOT;
-	else
-		cnp->cn_flags &= ~ISDOTDOT;
-	if (*ndp->ni_next == 0)
-		cnp->cn_flags |= ISLASTCN;
-	else
-		cnp->cn_flags &= ~ISLASTCN;
-
 	/*
 	 * Check for degenerate name (e.g. / or "")
 	 * which is a way of talking about a directory,
@@ -3878,7 +3898,7 @@ cache_fplookup_impl(struct vnode *dvp, struct cache_fp
 			break;
 		}
 
-		if (__predict_false(cnp->cn_flags & ISDOTDOT)) {
+		if (__predict_false(cache_fpl_isdotdot(cnp))) {
 			error = cache_fplookup_dotdot(fpl);
 			if (__predict_false(error != 0)) {
 				break;
@@ -3901,7 +3921,7 @@ cache_fplookup_impl(struct vnode *dvp, struct cache_fp
 
 		VNPASS(!seqc_in_modify(fpl->tvp_seqc), fpl->tvp);
 
-		if (cnp->cn_flags & ISLASTCN) {
+		if (cache_fpl_islastcn(ndp)) {
 			error = cache_fplookup_final(fpl);
 			break;
 		}
@@ -4082,7 +4102,9 @@ cache_fplookup(struct nameidata *ndp, enum cache_fpl_s
 		break;
 	case CACHE_FPL_STATUS_PARTIAL:
 		*pwdp = fpl.pwd;
-		cache_fpl_restore(&fpl, &fpl.snd);
+		/*
+		 * Status restored by cache_fplookup_partial_setup.
+		 */
 		break;
 	case CACHE_FPL_STATUS_ABORTED:
 		cache_fpl_restore(&fpl, &orig);