[src/trunk]: src/sys/nfs - do FILESYNC writes if we're freeing the page or th...

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

details:   https://anonhg.NetBSD.org/src/rev/c48f31c01180
branches:  trunk
changeset: 545623:c48f31c01180
user:      yamt <yamt%NetBSD.org@localhost>
date:      Sat Apr 12 06:53:09 2003 +0000

description:
- do FILESYNC writes if we're freeing the page or the page doesn't
  belong to us.  otherwise, data will be lost on server crash.
- use b_bcount instead of b_bufsize to determine
  how many pages we should deal with.

based on a patch from Chuck Silvers.
discussed on tech-kern.

diffstat:

 sys/nfs/nfs_bio.c |  13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diffs (44 lines):

diff -r 6dc1b2f7ea82 -r c48f31c01180 sys/nfs/nfs_bio.c
--- a/sys/nfs/nfs_bio.c Sat Apr 12 06:42:38 2003 +0000
+++ b/sys/nfs/nfs_bio.c Sat Apr 12 06:53:09 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nfs_bio.c,v 1.89 2003/04/09 14:30:30 yamt Exp $        */
+/*     $NetBSD: nfs_bio.c,v 1.90 2003/04/12 06:53:09 yamt Exp $        */
 
 /*
  * Copyright (c) 1989, 1993
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nfs_bio.c,v 1.89 2003/04/09 14:30:30 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nfs_bio.c,v 1.90 2003/04/12 06:53:09 yamt Exp $");
 
 #include "opt_nfs.h"
 #include "opt_ddb.h"
@@ -990,7 +990,7 @@
                bp->b_error = error;
            }
        } else {
-           int i, npages = bp->b_bufsize >> PAGE_SHIFT;
+           int i, npages = (bp->b_bcount + PAGE_SIZE - 1) >> PAGE_SHIFT;
            struct vm_page *pgs[npages];
            boolean_t needcommit = TRUE;
 
@@ -1003,9 +1003,16 @@
            for (i = 0; i < npages; i++) {
                    pgs[i] = uvm_pageratop((vaddr_t)bp->b_data +
                                           (i << PAGE_SHIFT));
+                   KASSERT((pgs[i]->flags & PG_BUSY) ||
+                       pgs[i]->uobject != (struct uvm_object *)vp);
                    if ((pgs[i]->flags & PG_NEEDCOMMIT) == 0) {
                            needcommit = FALSE;
                    }
+                   if ((pgs[i]->flags & (PG_RELEASED|PG_PAGEOUT)) ||
+                       pgs[i]->uobject != (struct uvm_object *)vp) {
+                           KASSERT(i == 0 || iomode == NFSV3WRITE_FILESYNC);
+                           iomode = NFSV3WRITE_FILESYNC;
+                   }
            }
            if (!needcommit && iomode == NFSV3WRITE_UNSTABLE) {
                    for (i = 0; i < npages; i++) {