[src/trunk]: src/sys/nfs comments in nfs_doio_write.

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

details:   https://anonhg.NetBSD.org/src/rev/5253fd2da9ff
branches:  trunk
changeset: 557497:5253fd2da9ff
user:      yamt <yamt%NetBSD.org@localhost>
date:      Sat Jan 10 14:52:53 2004 +0000

description:
comments in nfs_doio_write.

diffstat:

 sys/nfs/nfs_bio.c |  18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diffs (48 lines):

diff -r cad6c3304a7d -r 5253fd2da9ff sys/nfs/nfs_bio.c
--- a/sys/nfs/nfs_bio.c Sat Jan 10 14:49:44 2004 +0000
+++ b/sys/nfs/nfs_bio.c Sat Jan 10 14:52:53 2004 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nfs_bio.c,v 1.114 2003/12/07 21:15:46 fvdl Exp $       */
+/*     $NetBSD: nfs_bio.c,v 1.115 2004/01/10 14:52:53 yamt Exp $       */
 
 /*
  * Copyright (c) 1989, 1993
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nfs_bio.c,v 1.114 2003/12/07 21:15:46 fvdl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nfs_bio.c,v 1.115 2004/01/10 14:52:53 yamt Exp $");
 
 #include "opt_nfs.h"
 #include "opt_ddb.h"
@@ -967,7 +967,7 @@
        boolean_t stalewriteverf = FALSE;
        int i, npages = (bp->b_bcount + PAGE_SIZE - 1) >> PAGE_SHIFT;
        struct vm_page *pgs[npages];
-       boolean_t needcommit = TRUE;
+       boolean_t needcommit = TRUE; /* need only COMMIT RPC */
        boolean_t pageprotected;
        struct uvm_object *uobj = &vp->v_uobj;
        int error;
@@ -991,8 +991,20 @@
                         * this page belongs to our object.
                         */
                        simple_lock(&uobj->vmobjlock);
+                       /*
+                        * write out the page stably if it's about to
+                        * be released because we can't resend it
+                        * on the server crash.
+                        *
+                        * XXX assuming PG_RELEASE|PG_PAGEOUT won't be
+                        * changed until unbusy the page.
+                        */
                        if (pgs[i]->flags & (PG_RELEASED|PG_PAGEOUT))
                                iomode = NFSV3WRITE_FILESYNC;
+                       /*
+                        * if we met a page which hasn't been sent yet,
+                        * we need do WRITE RPC.
+                        */
                        if ((pgs[i]->flags & PG_NEEDCOMMIT) == 0)
                                needcommit = FALSE;
                        simple_unlock(&uobj->vmobjlock);