Date: Sun, 9 Nov 2008 15:39:48 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: Steve Kargl <sgk@troutmask.apl.washington.edu>, freebsd-geom@freebsd.org Subject: Re: RW and RO semantic and unable to umount a partition? Message-ID: <20081109133948.GN18100@deviant.kiev.zoral.com.ua> In-Reply-To: <20081109111917.GB2340@garage.freebsd.pl> References: <20081107192150.GA3007@troutmask.apl.washington.edu> <20081109111917.GB2340@garage.freebsd.pl>
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--ueS8F0zlRxS4iow4 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Nov 09, 2008 at 12:19:17PM +0100, Pawel Jakub Dawidek wrote: > On Fri, Nov 07, 2008 at 11:21:50AM -0800, Steve Kargl wrote: > > So, I may have done something in the category of "Don't do that!". > >=20 > > On node n19, I export /dev/ad4s1e and combine it into a mirror > > on node n18 with n18's /dev/ad4s1e. On n18 I have /dev/mirror/data, > > and I've successfully mounted /dev/mirror/data: > >=20 > > n18:root[32] mount /dev/mirror/data /data > >=20 > > Now, I tried the the following: > >=20 > > On n18, I created /etc/gg.exports > >=20 > > n18:root[33] cat /etc/gg.exports > > 192.168.0.17 RW /dev/mirror/data > > n18:root[34] ggated -v > >=20 > > On node n17 (yes, a third system). I do > >=20 > > n17:root[08] ggatec create -o rw 192.168.0.18 /dev/mirror/data > >=20 > > The above command does not create /dev/ggate0. So, I tried=20 >=20 > Because /dev/mirror/data is already open for writting by UFS. If you > unmount /data on n18, you will be able to attach /dev/mirror/data on n17 > for writting. >=20 > > ggatec create -o ro 192.168.0.18 /dev/mirror/data > >=20 > > This created the /dev/ggate0 device. Now, the interesting > > part > >=20 > > n17:root[10] mount /dev/ggate0 /mnt > > n17:root[11] ls /mnt > > .snap/ fcurra/ kargl/ > > n17:root[12] umount /mnt > > umount: unmount of /mnt failed: Operation not permitted > > n17:root[13] umount -f /mnt > > umount: unmount of /mnt failed: Operation not permitted > >=20 > > Three questions. Why is RW not permitted? Why does umount > > fail? How the heck to I force umount or the unmounting of /mnt? >=20 > Not sure why. It might be that file system changed under you (node n18 > modified it), so now n17 sees some strange inconsistencies. >=20 > All in all, you can eigher mount the same file system multiple times > read-only OR one time read-write and zero times read-only. Better not mount ufs volume more then once regardless of the mount mode. See the start of the ffs_mountfs(). ffs mount modifies devvp bufobj with reference to geom consumer. --ueS8F0zlRxS4iow4 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkkW6CQACgkQC3+MBN1Mb4ht4QCeICjRs4f6sU3E5B2FwwceN5sB sC0AoITKVLjgiSblDthbP8JwcNv2iZwa =HhYT -----END PGP SIGNATURE----- --ueS8F0zlRxS4iow4--
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