#Linux 6.18 Will Further Complicate Non-#GPL Out-Of-Tree #FileSystems
A patch queued up for Linux 6.18 merge window removes #write_cache_pages. In turn this will cause issues for #nonGPL out-of-tree file-systems for writing dirty data from the page cache. After the #NTFS3 and #Bcachefs in-tree users of the iterator were moved off of it, for Linux 6.18 the "write_cache_pages" will be removed that is depended upon by out-of-tree, non-GPL file-systems.
https://www.phoronix.com/news/Linux-6.18-write-cache-pages
Also affects #OpenZFS
Linux 6.18 Will Further Complicate Non-GPL Out-Of-Tree File-Systems

Out-of-tree file-system drivers not licensed/compatible with the GPL will have a new obstacle to deal with come time for Linux 6.18 later this year.