[src/trunk]: src/sys/fs/puffs Improve zero-fill of last page after shrink fix:

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

details:   https://anonhg.NetBSD.org/src/rev/22a983d2364b
branches:  trunk
changeset: 332719:22a983d2364b
user:      manu <manu%NetBSD.org@localhost>
date:      Mon Oct 06 04:41:59 2014 +0000

description:
Improve zero-fill of last page after shrink fix:
1) do it only if the file is open for writing, otherwise we send write
requests to the FS on a file that has never been open.
2) do it inside existing if (vap->va_size != VNOVAL) block

diffstat:

 sys/fs/puffs/puffs_vnops.c |  32 ++++++++++++++++++--------------
 1 files changed, 18 insertions(+), 14 deletions(-)

diffs (81 lines):

diff -r 0d461bccbc5c -r 22a983d2364b sys/fs/puffs/puffs_vnops.c
--- a/sys/fs/puffs/puffs_vnops.c        Sun Oct 05 23:08:01 2014 +0000
+++ b/sys/fs/puffs/puffs_vnops.c        Mon Oct 06 04:41:59 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: puffs_vnops.c,v 1.189 2014/10/05 09:28:24 justin Exp $ */
+/*     $NetBSD: puffs_vnops.c,v 1.190 2014/10/06 04:41:59 manu Exp $   */
 
 /*
  * Copyright (c) 2005, 2006, 2007  Antti Kantee.  All Rights Reserved.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.189 2014/10/05 09:28:24 justin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.190 2014/10/06 04:41:59 manu Exp $");
 
 #include <sys/param.h>
 #include <sys/buf.h>
@@ -1141,6 +1141,9 @@
 
        if (trunc_page(off) == off)
                return;
+ 
+       if (vp->v_writecount == 0)
+               return;
 
        len = round_page(off) - off;
        memset(zbuf, 0, len);
@@ -1157,7 +1160,7 @@
        error = ubc_uiomove(&vp->v_uobj, &uio, len,
                            UVM_ADV_SEQUENTIAL, UBC_WRITE|UBC_UNMAP_FLAG(vp));
        if (error)
-               DPRINTF(("zero-fill 0x%lx@0x%" PRIx64 " => %d\n", len, off, error));
+               DPRINTF(("zero-fill 0x%lx@0x%llx => %d\n", len, off, error));
 
        return;
 }
@@ -1168,6 +1171,7 @@
        PUFFS_MSG_VARS(vn, setattr);
        struct puffs_mount *pmp = MPTOPUFFSMP(vp->v_mount);
        struct puffs_node *pn = vp->v_data;
+       vsize_t oldsize = vp->v_size;
        int error = 0;
 
        KASSERT(!(flags & SETATTR_CHSIZE) || mutex_owned(&pn->pn_sizemtx));
@@ -1223,17 +1227,6 @@
        if ((flags & SETATTR_ASYNC) == 0)
                error = puffs_msg_wait2(pmp, park_setattr, vp->v_data, NULL);
 
-       /*
-        * If we truncate the file, make sure we zero-fill
-        * the end of the last page, otherwise if the file
-        * is later truncated to a larger size (creating a
-        * a hole), that area will not return zeroes as it
-        * should.
-        */
-       if ((error == 0) && (flags & SETATTR_CHSIZE) &&
-           (vap->va_size != VNOVAL) && (vap->va_size < vp->v_size))
-               zerofill_lastpage(vp, vap->va_size);
-
        if ((error == 0) && PUFFS_USE_FS_TTL(pmp)) {
                struct timespec *va_ttl = &setattr_msg->pvnr_va_ttl;
                struct vattr *rvap = &setattr_msg->pvnr_va;
@@ -1251,6 +1244,17 @@
        }
 
        if (vap->va_size != VNOVAL) {
+               /*
+                * If we truncated the file, make sure the data beyond 
+                * EOF in last page does not remain in cache, otherwise 
+                * if the file is later truncated to a larger size (creating
+                * a hole), that area will not return zeroes as it
+                * should. 
+                */
+               if ((flags & SETATTR_CHSIZE) && PUFFS_USE_PAGECACHE(pmp) && 
+                   (vap->va_size < oldsize))
+                       zerofill_lastpage(vp, vap->va_size);
+
                pn->pn_serversize = vap->va_size;
                if (flags & SETATTR_CHSIZE)
                        uvm_vnp_setsize(vp, vap->va_size);