git: d2336460daff - stable/12 - tmpfs: push VEXEC check into tmpfs_lookup()

[Kyle Evans]

The branch stable/12 has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=d2336460daffae7d2cb2344f52054a7a7a0047ad

commit d2336460daffae7d2cb2344f52054a7a7a0047ad
Author:     Kyle Evans <kevans at FreeBSD.org>
AuthorDate: 2021-01-28 14:27:28 +0000
Commit:     Kyle Evans <kevans at FreeBSD.org>
CommitDate: 2021-02-01 05:44:09 +0000

    tmpfs: push VEXEC check into tmpfs_lookup()
    
    vfs_cache_lookup() has already done the appropriate VEXEC check, therefore
    we must not re-check in VOP_CACHEDLOOKUP.
    
    This fixes O_SEARCH semantics on tmpfs and removes a redundant descent into
    VOP_ACCESS() in the common case.
    
    Reported-by:    arichardson (via CheriBSD Jenkins CI)
    
    (cherry picked from commit 0f919ed4ae4df082eefb517afe02752b1790afd3)
---
 sys/fs/tmpfs/tmpfs_vnops.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/sys/fs/tmpfs/tmpfs_vnops.c b/sys/fs/tmpfs/tmpfs_vnops.c
index bfb84c508c78..7df835113397 100644
--- a/sys/fs/tmpfs/tmpfs_vnops.c
+++ b/sys/fs/tmpfs/tmpfs_vnops.c
@@ -86,14 +86,10 @@ tmpfs_lookup1(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
 	struct tmpfs_mount *tm;
 	int error;
 
+	/* Caller assumes responsibility for ensuring access (VEXEC). */
 	dnode = VP_TO_TMPFS_DIR(dvp);
 	*vpp = NULLVP;
 
-	/* Check accessibility of requested node as a first step. */
-	error = vn_dir_check_exec(dvp, cnp);
-	if (error != 0)
-		goto out;
-
 	/* We cannot be requesting the parent directory of the root node. */
 	MPASS(IMPLIES(dnode->tn_type == VDIR &&
 	    dnode->tn_dir.tn_parent == dnode,
@@ -236,8 +232,17 @@ tmpfs_cached_lookup(struct vop_cachedlookup_args *v)
 static int
 tmpfs_lookup(struct vop_lookup_args *v)
 {
+	struct vnode *dvp = v->a_dvp;
+	struct vnode **vpp = v->a_vpp;
+	struct componentname *cnp = v->a_cnp;
+	int error;
 
-	return (tmpfs_lookup1(v->a_dvp, v->a_vpp, v->a_cnp));
+	/* Check accessibility of requested node as a first step. */
+	error = vn_dir_check_exec(dvp, cnp);
+	if (error != 0)
+		return (error);
+
+	return (tmpfs_lookup1(dvp, vpp, cnp));
 }
 
 static int