[src/trunk]: src/sys/ufs/lfs some comments

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

details:   https://anonhg.NetBSD.org/src/rev/a77de108fc74
branches:  trunk
changeset: 552165:a77de108fc74
user:      yamt <yamt%NetBSD.org@localhost>
date:      Sat Sep 20 17:51:55 2003 +0000

description:
some comments

diffstat:

 sys/ufs/lfs/lfs_vnops.c |  20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diffs (62 lines):

diff -r 19e2308c30d5 -r a77de108fc74 sys/ufs/lfs/lfs_vnops.c
--- a/sys/ufs/lfs/lfs_vnops.c   Sat Sep 20 17:17:40 2003 +0000
+++ b/sys/ufs/lfs/lfs_vnops.c   Sat Sep 20 17:51:55 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: lfs_vnops.c,v 1.114 2003/08/07 16:34:40 agc Exp $      */
+/*     $NetBSD: lfs_vnops.c,v 1.115 2003/09/20 17:51:55 yamt Exp $     */
 
 /*-
  * Copyright (c) 1999, 2000, 2001, 2002, 2003 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lfs_vnops.c,v 1.114 2003/08/07 16:34:40 agc Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lfs_vnops.c,v 1.115 2003/09/20 17:51:55 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1335,6 +1335,11 @@
        if ((ap->a_access_type & VM_PROT_WRITE) != 0) {
                LFS_SET_UINO(VTOI(ap->a_vp), IN_MODIFIED);
        }
+
+       /*
+        * we're relying on the fact that genfs_getpages() always read in
+        * entire filesystem blocks.
+        */
        return genfs_getpages(v);
 }
 
@@ -1357,7 +1362,11 @@
        struct lwp *l = curlwp ? curlwp : &lwp0;
        off_t soff;
        voff_t off;
-       int i, dirty, tdirty, nonexistent, any_dirty;
+       int i;
+       int nonexistent;
+       int any_dirty;  /* number of dirty pages */
+       int dirty;      /* number of dirty pages in a block */
+       int tdirty;
        int pages_per_block = fs->lfs_bsize >> PAGE_SHIFT;
 
   top:
@@ -1374,6 +1383,9 @@
        }
        while (by_list || soff < MIN(blkeof, endoffset)) {
                if (by_list) {
+                       /*
+                        * find the first page in a block.
+                        */
                        if (pages_per_block > 1) {
                                while (curpg && (curpg->offset & fs->lfs_bmask))
                                        curpg = TAILQ_NEXT(curpg, listq);
@@ -1524,6 +1536,8 @@
  *     block are either resident or not, even if those pages are higher
  *     than EOF; that means that we will be getting requests to free
  *     "unused" pages above EOF all the time, and should ignore them.
+ *
+ * XXX note that we're (ab)using PGO_LOCKED as "seglock held".
  */
 
 int