On Tue 12-12-23 04:36:45, Matthew Wilcox wrote: > On Wed, Dec 06, 2023 at 08:37:57PM +0100, Jan Kara wrote: > > Within the same page buffered reads and writes should be consistent because > > they are synchronized by the page lock. However once reads and writes > > involve multiple pages, there is no serialization so you can get contents > > of some pages before write and some pages after being written. However this > > doesn't seem to be your particular case here. I just wanted to point out > > that in general even buffered reads vs writes are not fully consistent. > > Buffered reads don't take the page/folio lock. We only use the folio > lock to avoid reading stale data from the page cache while we're > fetching the data from storage. Once the uptodate flag is set on the > folio, we never take the folio lock for reads. Right, I've noticed once I've reread the code but thanks for correction anyway. :) Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
