On Mon, Nov 11, 2024 at 06:06:57PM +1030, Qu Wenruo wrote: > > Why? They aren't exactly efficient, and it's just going to create > > more Churn for Goldwyn's iomap work. > > So it is not recommended to go the write_begin() and write_end() callbacks > at all? > Or just not recommended for btrfs? They aren't a very efficient model, so I would not recommend to add new users. > I know there are limits like those call backs do not support IOCB_NOWAIT, > and the memory allocation inefficient problem (it should only affect ocfs2), > but shouldn't we encourage to use the more common paths where all other fses > go? I'd recommend to use iomap. > > And that scheme was one of my suggestions back then, together with > > removing write_begin/end from address_space_operations because they > > aren't operations called by MM/pagecache code, but just callbacks > > provided by the file system to perform_generic_write. > > > > Mind to point me to the old discussion thread? I'd like to know why we > didn't go that path. Probably because no one did the work yet. I don't have a pointer at hand, but it was a discussion willy kicked up about converting write_begin/end to folios.
