Re: [PATCH 18/32] fs: Provide operation for fetching mapping_metadata_bhs

On Wed, Mar 04, 2026 at 02:38:41PM +0100, Jan Kara wrote:
> I was looking into that. Passing these to sync_mapping_buffers(),
> invalidate_inode_buffers() is easy. Passing to mark_buffer_dirty_inode() is
> relatively tedious but doable. Where it gets difficult are calls like
> bforget() and most importantly try_to_free_buffers() on bdev mapping where
> you currently have no way to get to the mmb struct... We do have
> b_assoc_map pointer in buffer_head which we could switch to point to mmb
> instead but IO error handling on bhs needs to get to the mapping from bh so
> we'd then have to add address_space pointer to mmb for these uses. All in
> all it's doable but I've decided it isn't really worth it.

I guess a backpointer from the bh list to the mapping/inode would solve
all this?  Or am I missing something?