From 629314041114ee9ebce5303195cc9b7eb83b4ba4 Mon Sep 17 00:00:00 2001
From: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Date: Fri, 30 Nov 2012 22:59:20 +0000
Subject: [PATCH] IFp4 @208382:

Currently on each record write we call VFS_STATFS() to get available space
on the file system as well as VOP_GETATTR() to get trail file size.

We can assume that trail file is only updated by the audit worker, so instead
of asking for file size on every write, get file size on trail switch only
(it should be zero, but it's not expensive) and use global variable audit_size
protected by the audit worker lock to keep track of trail file's size.

This eliminates VOP_GETATTR() call for every write. VFS_STATFS() is satisfied
from in-memory data (mount->mnt_stat), so shouldn't be expensive.

Sponsored by:	FreeBSD Foundation (auditdistd)
MFC after:	2 weeks
---
 sys/security/audit/audit_worker.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/sys/security/audit/audit_worker.c b/sys/security/audit/audit_worker.c
index 6247e4971f8d..dd0eac724c44 100644
--- a/sys/security/audit/audit_worker.c
+++ b/sys/security/audit/audit_worker.c
@@ -88,6 +88,7 @@ static struct proc		*audit_thread;
 static int		 audit_file_rotate_wait;
 static struct ucred	*audit_cred;
 static struct vnode	*audit_vp;
+static off_t		 audit_size;
 static struct sx	 audit_worker_lock;
 
 #define	AUDIT_WORKER_LOCK_INIT()	sx_init(&audit_worker_lock, \
@@ -115,7 +116,6 @@ audit_record_write(struct vnode *vp, struct ucred *cred, void *data,
 	struct statfs *mnt_stat;
 	int error;
 	static int cur_fail;
-	struct vattr vattr;
 	long temp;
 
 	AUDIT_WORKER_LOCK_ASSERT();
@@ -133,12 +133,6 @@ audit_record_write(struct vnode *vp, struct ucred *cred, void *data,
 	error = VFS_STATFS(vp->v_mount, mnt_stat);
 	if (error)
 		goto fail;
-	vn_lock(vp, LK_SHARED | LK_RETRY);
-	error = VOP_GETATTR(vp, &vattr, cred);
-	VOP_UNLOCK(vp, 0);
-	if (error)
-		goto fail;
-	audit_fstat.af_currsz = vattr.va_size;
 
 	/*
 	 * We handle four different space-related limits:
@@ -196,7 +190,7 @@ audit_record_write(struct vnode *vp, struct ucred *cred, void *data,
 	 * records may be generated before the daemon rotates the file.
 	 */
 	if ((audit_fstat.af_filesz != 0) && (audit_file_rotate_wait == 0) &&
-	    (vattr.va_size >= audit_fstat.af_filesz)) {
+	    (audit_size >= audit_fstat.af_filesz)) {
 		AUDIT_WORKER_LOCK_ASSERT();
 
 		audit_file_rotate_wait = 1;
@@ -238,6 +232,8 @@ audit_record_write(struct vnode *vp, struct ucred *cred, void *data,
 		goto fail_enospc;
 	else if (error)
 		goto fail;
+	AUDIT_WORKER_LOCK_ASSERT();
+	audit_size += len;
 
 	/*
 	 * Catch completion of a queue drain here; if we're draining and the
@@ -448,10 +444,20 @@ audit_rotate_vnode(struct ucred *cred, struct vnode *vp)
 {
 	struct ucred *old_audit_cred;
 	struct vnode *old_audit_vp;
+	struct vattr vattr;
 
 	KASSERT((cred != NULL && vp != NULL) || (cred == NULL && vp == NULL),
 	    ("audit_rotate_vnode: cred %p vp %p", cred, vp));
 
+	if (vp != NULL) {
+		vn_lock(vp, LK_SHARED | LK_RETRY);
+		if (VOP_GETATTR(vp, &vattr, cred) != 0)
+			vattr.va_size = 0;
+		VOP_UNLOCK(vp, 0);
+	} else {
+		vattr.va_size = 0;
+	}
+
 	/*
 	 * Rotate the vnode/cred, and clear the rotate flag so that we will
 	 * send a rotate trigger if the new file fills.
@@ -461,6 +467,7 @@ audit_rotate_vnode(struct ucred *cred, struct vnode *vp)
 	old_audit_vp = audit_vp;
 	audit_cred = cred;
 	audit_vp = vp;
+	audit_size = vattr.va_size;
 	audit_file_rotate_wait = 0;
 	audit_enabled = (audit_vp != NULL);
 	AUDIT_WORKER_UNLOCK();