Re: Warning: bad fsid on block 20971520

On Wed, Jan 11, 2012 at 04:46:21PM +0100, David Sterba wrote:

Hi,

the $subj warning appears sometimes in syslog, in my case when
xfstests/209 runs looped. The minimal reproducer is looped mkfs+mount.

I've been seeing this as well.  It's new with 3.2, and I haven't yet
been able to track it down.

The first thing that happens when we mount the FS is a block layer
invalidate, and that must be dropping the write.

It's also possible (but very unlikely) that mkfs.btrfs is neglecting to
write that block.

Do you have a reliable way to reproduce?  If so, can you try with a much
older mkfs.btrfs.

-chris