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Date:   Fri, 17 Jan 2020 15:40:55 +0100
From:   Krzysztof Kozlowski <krzk@kernel.org>
To:     David Howells <dhowells@redhat.com>
Cc:     Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        linux-nfs@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Scott Mayhew <smayhew@redhat.com>,
        Arnd Bergmann <arnd@arndb.de>
Subject: Re: [BISECT BUG] NFS v4 root not working after 6d972518b821 ("NFS:
 Add fs_context support.")
Message-ID: <20200117144055.GB3215@pi3>
References: <CAJKOXPeCVwZfBsCVbc9RQUGi0UfWQw0uFamPiQasiO8fSthFsQ@mail.gmail.com>
 <433863.1579270803@warthog.procyon.org.uk>
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On Fri, Jan 17, 2020 at 02:20:03PM +0000, David Howells wrote:
> You seem to be running afoul of the check here:
> 
> 	case Opt_minorversion:
> 		if (result.uint_32 > NFS4_MAX_MINOR_VERSION)
> 			goto out_of_bounds;
> 		ctx->minorversion = result.uint_32;
> 		break;
> 
> which would seem to indicate that the mount process is supplying
> minorversion=X as an option.  Can you modify your kernel to print param->key
> and param->string at the top of nfs_fs_context_parse_param()?  Adding
> something like:
> 
> 	pr_notice("NFSOP '%s=%s'\n", param->key, param->string);
> 
> will likely suffice unless you're directly driving the new mount API - in
> which case param->string might be things other than a string, but that's
> unlikely.  It might also be NULL, but printk should handle that.

The output:

NFS-Mount: 192.168.1.10:/srv/nfs/odroidhc1
Waiting 10 seconds for device /dev/nfs ...
[   14.652366] random: crng init done
Mount cmd:
mount.nfs4 -o vers=4,nolock 192.168.1.10:/srv/nfs/odroidhc1 /new_root
[   22.938314] NFSOP 'source=192.168.1.10:/srv/nfs/odroidhc1'
[   22.942638] NFSOP 'nolock=(null)'
[   22.945772] NFSOP 'vers=4.2'
[   22.948660] NFSOP 'addr=192.168.1.10'
[   22.952350] NFSOP 'clientaddr=192.168.1.12'
[   22.956831] NFS4: Couldn't follow remote path
[   22.971001] NFSOP 'source=192.168.1.10:/srv/nfs/odroidhc1'
[   22.975217] NFSOP 'nolock=(null)'
[   22.978444] NFSOP 'vers=4'
[   22.981265] NFSOP 'minorversion=1'
[   22.984513] NFS: Value for 'minorversion' out of range
mount.nfs4: Numerical result out of range
:: running cleanup hook [udev]
ERROR: Failed to mount the real root device.
Bailing out, you are on your own. Good luck.

sh: can't access tty; job control turned off

Best regards,
Krzysztof