From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: md device is read only mode Date: Tue, 10 Jul 2012 07:42:01 +1000 Message-ID: <20120710074201.76846af5@notabene.brown> References: <20120705172748.GA6464@lazy.lzy> <20120709114022.58f5d52b@notabene.brown> <20120709173406.GA4206@lazy.lzy> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/DWdiJqTpuUA=Ex0NONkVDpr"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20120709173406.GA4206@lazy.lzy> Sender: linux-raid-owner@vger.kernel.org To: Piergiorgio Sartor Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/DWdiJqTpuUA=Ex0NONkVDpr Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Mon, 9 Jul 2012 19:34:07 +0200 Piergiorgio Sartor wrote: > Hi Neil, >=20 > please see one comment below. >=20 > On Mon, Jul 09, 2012 at 11:40:22AM +1000, NeilBrown wrote: > [...] > > The mount system call will notice that the device is read-only, and wil= l make > > assume the read-only mount option. >=20 > OK, so it should work as expected. >=20 > The story was this. > After fixing the RAID-5 superblock problem, we > wanted to see if the filesystem was still OK. > So we started the RAID in r/o mode (so to avoid > any possible further damage from mount) and then > mounted the filesystem (actually, now that I > think of it, there was an LVM layer in the middle). > This mount caused a kernel error report (I do > not know if BUG() or else). >=20 > Is there any explanation for that? Probably LVM isn't detecting that the underlying device is readonly and so forcing the upper device to be readonly. md doesn't do this either - it should. NeilBrown --Sig_/DWdiJqTpuUA=Ex0NONkVDpr Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBT/tQKTnsnt1WYoG5AQJrkw//evleuHTCd1mf+VTDtJDMcnPkW3Epac9a FEWNFbQfBGhyxUrjdtAnInMy2z/zUkaaIkA3+4J2iR5kfZ0j6VttkMlUWJzF6l+R wTTt3rkGVuIsEmkggkH557GVXH/mNKoN8J+jGwdWZ67V/YPIcITA1WIt2PeqFZEc suYsahA73sKfNFg8IViumhtmWSxyBxM+PcDykL38ZUFq8iP8oSaW+KTq8aSV+3Vn 5nKI9wsxSu6hpQ7k+M/WDmB/2SSADRIUWqUvXWWZNNP1X17/g1jONQTQ4+t7opNR u9hogyE9JedvTmBlgn94im7naQtt2ZP4/WBLeefKvK8aQFZd69ey5xtc0/fswg5s R8lhyd4cDShLZfWGcOcbQeXXPg8sZmkf/Q3aKt5ydTqB8gAVULzQsB3I+rTYpD9z JVSyv7oXoQ0MdmwT/nX1fRSK6hDZHLDJpWCmHcYcVErLObNSmAO0yGCNrayM80uj WwEmLB209HkkApz2FupPMEBinjUbvBTR1NeD+HVwZ4PzRfvxCSYEhjpk/lErQcPR Hi00wivJrKqK+/WbxCXhWN6/M7eHu5I7BxjJpcPIsIyf3e5phLlQoNo7BrpxFBt6 IjAxB5rg/Rzw6YgcqjCKPBmbQjpVIfZXkE9vcT75T6+hqwkkbaImi3G+duERKHoH u2ECQE7i9gQ= =43Yj -----END PGP SIGNATURE----- --Sig_/DWdiJqTpuUA=Ex0NONkVDpr--