git: 5d745b399d31 - stable/13 - vfs: elide vnode locking when it is only needed for audit if possible

[Mateusz Guzik]

The branch stable/13 has been updated by mjg:

URL: https://cgit.FreeBSD.org/src/commit/?id=5d745b399d31c0a48b634e7eae6786ba2675194b

commit 5d745b399d31c0a48b634e7eae6786ba2675194b
Author:     Mateusz Guzik <mjg at FreeBSD.org>
AuthorDate: 2021-05-23 19:28:26 +0000
Commit:     Mateusz Guzik <mjg at FreeBSD.org>
CommitDate: 2021-06-07 00:34:52 +0000

    vfs: elide vnode locking when it is only needed for audit if possible
    
    (cherry picked from commit a269183875f6d5141c81277d41b552871e2171e5)
---
 sys/kern/vfs_syscalls.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 26a8d31e4456..c18bb56fc632 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -2802,9 +2802,11 @@ sys_fchflags(struct thread *td, struct fchflags_args *uap)
 	if (error != 0)
 		return (error);
 #ifdef AUDIT
-	vn_lock(fp->f_vnode, LK_SHARED | LK_RETRY);
-	AUDIT_ARG_VNODE1(fp->f_vnode);
-	VOP_UNLOCK(fp->f_vnode);
+	if (AUDITING_TD(td)) {
+		vn_lock(fp->f_vnode, LK_SHARED | LK_RETRY);
+		AUDIT_ARG_VNODE1(fp->f_vnode);
+		VOP_UNLOCK(fp->f_vnode);
+	}
 #endif
 	error = setfflags(td, fp->f_vnode, uap->flags);
 	fdrop(fp, td);
@@ -3303,9 +3305,11 @@ kern_futimes(struct thread *td, int fd, struct timeval *tptr,
 	if (error != 0)
 		return (error);
 #ifdef AUDIT
-	vn_lock(fp->f_vnode, LK_SHARED | LK_RETRY);
-	AUDIT_ARG_VNODE1(fp->f_vnode);
-	VOP_UNLOCK(fp->f_vnode);
+	if (AUDITING_TD(td)) {
+		vn_lock(fp->f_vnode, LK_SHARED | LK_RETRY);
+		AUDIT_ARG_VNODE1(fp->f_vnode);
+		VOP_UNLOCK(fp->f_vnode);
+	}
 #endif
 	error = setutimes(td, fp->f_vnode, ts, 2, tptr == NULL);
 	fdrop(fp, td);
@@ -3337,9 +3341,11 @@ kern_futimens(struct thread *td, int fd, struct timespec *tptr,
 	if (error != 0)
 		return (error);
 #ifdef AUDIT
-	vn_lock(fp->f_vnode, LK_SHARED | LK_RETRY);
-	AUDIT_ARG_VNODE1(fp->f_vnode);
-	VOP_UNLOCK(fp->f_vnode);
+	if (AUDITING_TD(td)) {
+		vn_lock(fp->f_vnode, LK_SHARED | LK_RETRY);
+		AUDIT_ARG_VNODE1(fp->f_vnode);
+		VOP_UNLOCK(fp->f_vnode);
+	}
 #endif
 	error = setutimes(td, fp->f_vnode, ts, 2, flags & UTIMENS_NULL);
 	fdrop(fp, td);