Am 25.08.2015 um 15:51 schrieb Chris Mason [off-list ref]:

quoted

On Tue, Aug 25, 2015 at 11:00:30AM +0200, Christoph Hellwig wrote:
I think this is btrfs using a struct block_device that doesn't have
a valid queue pointer in it's gendisk for ->s_bdev.  And there are
some fishy looking ->s_bdev assignments in the code which I suspect
are related to it:

fs/btrfs/dev-replace.c: if (fs_info->sb->s_bdev == src_device->bdev)
fs/btrfs/dev-replace.c:         fs_info->sb->s_bdev = tgt_device->bdev;
fs/btrfs/volumes.c:     if (device->bdev == root->fs_info->sb->s_bdev)
fs/btrfs/volumes.c:             root->fs_info->sb->s_bdev = next_device->bdev;
fs/btrfs/volumes.c:     if (tgtdev->bdev == fs_info->sb->s_bdev)
fs/btrfs/volumes.c:             fs_info->sb->s_bdev = next_device->bdev;

We've had trouble with this in the past, I'll take a look.

Any news?

-chris