Date: Sun, 7 Aug 2011 03:23:52 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: bf1783@gmail.com Cc: freebsd-current@freebsd.org, mm@freebsd.org Subject: Re: Recursive nullfs mounts and r224655 Message-ID: <20110807002351.GL17489@deviant.kiev.zoral.com.ua> In-Reply-To: <CAGFTUwPHLa-Lq6kQh6Q_efVd2XARHd-W_gnW-bnN-hd_9ZLCQg@mail.gmail.com> References: <CAGFTUwN9-m0Ts-1NSjPFMTGHGDuH64nOrGFmBZgEAk3_wXLqWA@mail.gmail.com> <20110806144325.GE17489@deviant.kiev.zoral.com.ua> <CAGFTUwPHLa-Lq6kQh6Q_efVd2XARHd-W_gnW-bnN-hd_9ZLCQg@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--C2H3fAq9VP7LQDT/
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
On Sat, Aug 06, 2011 at 08:11:32PM -0400, b. f. wrote:
> On 8/6/11, Kostik Belousov <kostikbel@gmail.com> wrote:
> > On Sat, Aug 06, 2011 at 04:44:25AM -0400, b. f. wrote:
> >> Recent changes to the kernel (sys/kern/vfs_mount.c, in r224655?)
> >> between r224550 and r224655 have broken my tinderbox setup. It had a
> >> tmpfs filesystem mounted at /T and a UFS filesystem mounted at /U,
> >> and, when setting up the tinderbox, performed:
> >>
> >> mkdir /U/u1
> >> mkdir /U/u2
> >> mkdir /T/t1
> >> mount -t nullfs /T/t1 /U/u1
> >> mkdir-p /U/u1/u3/u4
> >> mount -t nullfs /U/u2 /U/u1/u3/u4
> >> ...
> >>
> >> This worked at r224550 and before. It now fails at the second nullfs
> >> mount, with ENOENT("mount_nullfs: No such file or directory").
> > r224615 and r224655 must be reverted.
> >
> > The reason for your trouble is that nullfs cannot cache any vnodes,
> > thus reclaiming anything that get reference count of 0. This interacts
> > badly with VOP_VNTOCNP() which has to operate on the vnodes with
> > zero refcount, since we cannot decrement refcount under the namecache
> > lock.
> >
> > Trying to update vptocnp(9) interface is too intrusive change for freeze
> > period.
> >
>=20
>=20
> Thank you for the analysis, it will make fixing this problem locally a
> bit easier, while you sort it out. Does 224614 have a bearing on this
> problem, as well as 224615?
>=20
> b.
You are right, r224614 and r224655 are revisions that shall be reverted.
--C2H3fAq9VP7LQDT/
Content-Type: application/pgp-signature
Content-Disposition: inline
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (FreeBSD)
iEYEARECAAYFAk492xcACgkQC3+MBN1Mb4gE0ACfXKSWa1qumMZYKYwKnVUE8qi8
6BcAniUBvzovjkTzSVN4HI8cU4p4YEx7
=42Yh
-----END PGP SIGNATURE-----
--C2H3fAq9VP7LQDT/--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20110807002351.GL17489>