Re: [PATCH] do_mounts: try all available filesystems before panicking

[Dave Chinner]

On Mon, May 26, 2014 at 10:08:13AM +1000, Dave Chinner wrote:
> On Sun, May 25, 2014 at 01:04:09PM -0700, Linus Torvalds wrote:
> > On Mon, May 5, 2014 at 11:34 AM, Plamen Petrov <plamen.sisi@xxxxxxxxx> wrote:
> > >
> > > The story short: on systems with btrfs root I have a kernel .config with ext4,
> > > xfs and btrfs built-in which works fine with 3.13.x, but 3.14.x panics. After
> > > inserting some debug printks, I got this info from mount_block_root:
> > >
> > > ---> EACCESS=13, EINVAL=22, Available filesystems: ext3 ext2 ext4 fuseblk xfs btrfs
> > > -----> Tried ext3, error code is -22.
> > > -----> Tried ext2, error code is -22.
> > > -----> Tried ext4, error code is -22.
> > > -----> Tried fuseblk, error code is -22.
> > > -----> Tried xfs, error code is -38.
> > > VFS: Cannot open root device "sda2" or unknown-block(8,2): error -38
> > > Please append a correct "root=" boot option; here are the available partitions:

BTW, This is the original thread with lots of triage in it:

http://www.spinics.net/lists/linux-btrfs/msg33455.html

But that doesn't reach any conclusion. I suspect that the
change of btrfs init (from very early (@~1.8s into the boot) until a
few milliseconds before the root mount is changing the order in
which the filesystem type list is traversed by the mount, resulting
in XFS being used to probe the device before btrfs.

Why XFS is seeing /dev/sda2 as containing an XFS filesystem is not
yet clear, but perhaps once you've dumped the the first sector of
the btrfs partition all will become clear....

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/