Re: [PATCH v4 0/4] fs: allow to mount beneath top mount

[Seth Forshee <sforshee@kernel.org>]

On Wed, May 03, 2023 at 01:18:38PM +0200, Christian Brauner wrote:
> Changes in v4:
> - Tweak the logic and helper that's used to prevent mounting beneath a
>   mount if the propagation relationship between the source mount, parent
>   mount, and top mount would lead to nonsensical mount trees.
> - Link to v3: https://lore.kernel.org/r/20230202-fs-move-mount-replace-v3-0-377893f74bc8@kernel.org
> 
> Changes in v3:
> - Refuse to mount source trees whose root has been overmounted after
>   path resolution of the source path has finished but before we grabbed
>   the namespace semaphore. This avoids the creation of shadow mounts.
> - Refuse to mount if the mount we're mounting beneath has been moved to
>   a different mountpoint before we grabbed the namespace semaphore.
> - Refuse to mount if the mount we're mounting beneath has been unmounted
>   before we grabbed the namespace semaphore.
> - Link to v2: https://lore.kernel.org/r/20230202-fs-move-mount-replace-v2-0-f53cd31d6392@kernel.org
> 
> Changes in v2:
> - s/MOVE_MOUNT_TUCK/MOVE_MOUNT_BENEATH/ which is a much clearer name.
> - Improve commit message.
> - Link to v1: https://lore.kernel.org/r/20230202-fs-move-mount-replace-v1-0-9b73026d5f10@kernel.org

Reviewed the changes since my last review. I'll send one
follow up about some wording in a comment, but other than that LGTM.

Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>