Date: Fri, 22 Feb 2013 10:38:31 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Bruce Evans <brde@optusnet.com.au> Cc: fs@freebsd.org Subject: Re: cleaning files beyond EOF Message-ID: <20130222083831.GK2598@kib.kiev.ua> In-Reply-To: <20130217074832.GA2598@kib.kiev.ua> References: <20130217113031.N9271@besplex.bde.org> <20130217055528.GB2522@kib.kiev.ua> <20130217172928.C1900@besplex.bde.org> <20130217074832.GA2598@kib.kiev.ua>
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On Sun, Feb 17, 2013 at 09:48:32AM +0200, Konstantin Belousov wrote:
> But the ffs_getpages() might be indeed the culprit. It calls
> vm_page_zero_invalid(), which only has DEV_BSIZE granularity. I think
> that ffs_getpages() also should zero the after eof part of the last page
> of the file to fix your damage, since device read cannot read less than
> DEV_BSIZE.
>=20
Here is the updated patch, with the bug fixed which mis-calculated the
size for pmap_zero_page_area().
diff --git a/sys/ufs/ffs/ffs_vnops.c b/sys/ufs/ffs/ffs_vnops.c
index 5c99d5b..08508a4 100644
--- a/sys/ufs/ffs/ffs_vnops.c
+++ b/sys/ufs/ffs/ffs_vnops.c
@@ -829,9 +829,9 @@ static int
ffs_getpages(ap)
struct vop_getpages_args *ap;
{
- int i;
vm_page_t mreq;
- int pcount;
+ uint64_t size;
+ int i, isize, pcount;
=20
pcount =3D round_page(ap->a_count) / PAGE_SIZE;
mreq =3D ap->a_m[ap->a_reqpage];
@@ -846,6 +846,11 @@ ffs_getpages(ap)
if (mreq->valid) {
if (mreq->valid !=3D VM_PAGE_BITS_ALL)
vm_page_zero_invalid(mreq, TRUE);
+ size =3D VTOI(ap->a_vp)->i_size;
+ if (mreq->pindex =3D=3D OFF_TO_IDX(size)) {
+ isize =3D size & PAGE_MASK;
+ pmap_zero_page_area(mreq, isize, PAGE_SIZE - isize);
+ }
for (i =3D 0; i < pcount; i++) {
if (i !=3D ap->a_reqpage) {
vm_page_lock(ap->a_m[i]);
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