[src/trunk]: src/sys/kern Do the space accounting before VOP_INACTIVE() so we...

[hannken <hannken%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/a92c147e4ef8
branches:  trunk
changeset: 361605:a92c147e4ef8
user:      hannken <hannken%NetBSD.org@localhost>
date:      Thu Feb 17 14:39:51 2022 +0000

description:
Do the space accounting before VOP_INACTIVE() so we may
unlock the vnode after VOP_INCATIVE().

This was the last call from vrelel() to VOP_UNLOCK() with v_interlock held.

diffstat:

 sys/kern/vfs_vnode.c |  56 ++++++++++++++++++++++++++++++++++++---------------
 1 files changed, 39 insertions(+), 17 deletions(-)

diffs (117 lines):

diff -r 6146938e0198 -r a92c147e4ef8 sys/kern/vfs_vnode.c
--- a/sys/kern/vfs_vnode.c      Thu Feb 17 14:39:14 2022 +0000
+++ b/sys/kern/vfs_vnode.c      Thu Feb 17 14:39:51 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_vnode.c,v 1.132 2022/02/17 14:39:14 hannken Exp $  */
+/*     $NetBSD: vfs_vnode.c,v 1.133 2022/02/17 14:39:51 hannken Exp $  */
 
 /*-
  * Copyright (c) 1997-2011, 2019, 2020 The NetBSD Foundation, Inc.
@@ -148,7 +148,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.132 2022/02/17 14:39:14 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.133 2022/02/17 14:39:51 hannken Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_pax.h"
@@ -779,10 +779,12 @@
 vrelel(vnode_t *vp, int flags, int lktype)
 {
        const bool async = ((flags & VRELEL_ASYNC) != 0);
-       bool recycle, defer;
+       bool recycle, defer, objlock_held;
        u_int use, next;
        int error;
 
+       objlock_held = false;
+
 retry:
        KASSERT(mutex_owned(vp->v_interlock));
 
@@ -805,6 +807,10 @@
                                VOP_UNLOCK(vp);
                                mutex_enter(vp->v_interlock);
                        }
+                       if (objlock_held) {
+                               objlock_held = false;
+                               rw_exit(vp->v_uobj.vmobjlock);
+                       }
                        if (vtryrele(vp)) {
                                mutex_exit(vp->v_interlock);
                                return;
@@ -886,6 +892,29 @@
        }
        KASSERT(lktype == LK_EXCLUSIVE);
 
+       if ((vp->v_iflag & (VI_TEXT|VI_EXECMAP|VI_WRMAP)) != 0 ||
+           (vp->v_vflag & VV_MAPPED) != 0) {
+               /* Take care of space accounting. */
+               if (!objlock_held) {
+                       objlock_held = true;
+                       if (!rw_tryenter(vp->v_uobj.vmobjlock, RW_WRITER)) {
+                               mutex_exit(vp->v_interlock);
+                               rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
+                               mutex_enter(vp->v_interlock);
+                               goto retry;
+                       }
+               }
+               if ((vp->v_iflag & VI_EXECMAP) != 0) {
+                       cpu_count(CPU_COUNT_EXECPAGES, -vp->v_uobj.uo_npages);
+               }
+               vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP);
+               vp->v_vflag &= ~VV_MAPPED;
+       }
+       if (objlock_held) {
+               objlock_held = false;
+               rw_exit(vp->v_uobj.vmobjlock);
+       }
+
        /*
         * Deactivate the vnode, but preserve our reference across
         * the call to VOP_INACTIVE().
@@ -898,7 +927,10 @@
        mutex_exit(vp->v_interlock);
        recycle = false;
        VOP_INACTIVE(vp, &recycle);
-       rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
+       if (!recycle) {
+               lktype = LK_NONE;
+               VOP_UNLOCK(vp);
+       }
        mutex_enter(vp->v_interlock);
 
        /*
@@ -916,28 +948,18 @@
                }
        }
 
-       /* Take care of space accounting. */
-       if ((vp->v_iflag & VI_EXECMAP) != 0) {
-               cpu_count(CPU_COUNT_EXECPAGES, -vp->v_uobj.uo_npages);
-       }
-       vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP);
-       vp->v_vflag &= ~VV_MAPPED;
-       rw_exit(vp->v_uobj.vmobjlock);
-
        /*
-        * Recycle the vnode if the file is now unused (unlinked),
-        * otherwise just free it.
+        * Recycle the vnode if the file is now unused (unlinked).
         */
        if (recycle) {
                VSTATE_ASSERT(vp, VS_BLOCKED);
+               KASSERT(lktype == LK_EXCLUSIVE);
                /* vcache_reclaim drops the lock. */
                lktype = LK_NONE;
                vcache_reclaim(vp);
-       } else {
-               lktype = LK_NONE;
-               VOP_UNLOCK(vp);
        }
        KASSERT(vrefcnt(vp) > 0);
+       KASSERT(lktype == LK_NONE);
 
 out:
        for (use = atomic_load_relaxed(&vp->v_usecount);; use = next) {