On Fri, May 13, 2022 at 04:39:28AM +0100, Matthew Wilcox wrote: > On Thu, May 12, 2022 at 10:41:41PM -0400, Josef Bacik wrote: > > On Thu, May 12, 2022 at 09:54:59PM +0100, Matthew Wilcox wrote: > > > The LWN writeup [1] on merging the MGLRU reminded me that I need to send > > > out a plan for removing page flags that we can do without. > > > > > > 1. PG_error. It's basically useless. If the page was read successfully, > > > PG_uptodate is set. If not, PG_uptodate is clear. The page cache > > > doesn't use PG_error. Some filesystems do, and we need to transition > > > them away from using it. > > > > > > > What about writes? A cursory look shows we don't clear Uptodate if we fail to > > write, which is correct I think. The only way to indicate we had a write error > > to check later is the page error. > > On encountering a write error, we're supposed to call mapping_set_error(), > not SetPageError(). > Yup I can't read, the places I was looking did mapping_set_error() in a different area from SetPageError() so I got confused, so this can be ripped out of btrfs with no problems. Thanks, Josef
