Re: [PATCH 05/17] btrfs: open block devices after superblock creation

[Christian Brauner <brauner@kernel.org>]

On Fri, Aug 11, 2023 at 12:08:16PM +0200, Christoph Hellwig wrote:
> Currently btrfs_mount_root opens the block devices before committing to
> allocating a super block. That creates problems for restricting the
> number of writers to a device, and also leads to a unusual and not very
> helpful holder (the fs_type).
> 
> Reorganize the code to first check whether the superblock for a
> particular fsid does already exist and open the block devices only if it
> doesn't, mirroring the recent changes to the VFS mount helpers.  To do
> this the increment of the in_use counter moves out of btrfs_open_devices
> and into the only caller in btrfs_mount_root so that it happens before
> dropping uuid_mutex around the call to sget.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Looks good to me,
Acked-by: Christian Brauner <brauner@kernel.org>

And ofc, would be great to get btrfs reviews.