> > > What remains is ctime/mtime support. > > > > > > Also fallocate/copyfile/reflink/etc will need some thought as we need > > > to not only flush out dirty pages, but in some cases prevent new > > > faults while the operation is in progress. > > > > Well, generic/503 which exercises these corners hangs > > (503.dmesg attached) > > That was just a stupid bug in truncate (truncating ovl page with upper > inode lock held -> ABBA deadlock). > > Attached the fix for that one. > Force pushed and re-tested. Summary of regressions of "quick" xfstests since v5.0-rc1: Wrong st_mtime/st_ctime: generic/003 generic/080 generic/215 EIO on clone/dedupe: generic/303 generic/304 Wrong st_blocks/fiemap: generic/353 generic/392 generic/422 New lazy copy up semantics: overlay/060 > > > > > > And after that it needs to be optimized (->readpages() and > > > ->writepages()), but I think that's the easy part. > > > > > > > And we also need to flush pages on non direct IO cases > > of ->writepages() and then we can revert: > > e8d4bfe3a715 ovl: Sync upper dirty data when syncing overlayfs > > and swoop the grand prize :) > > Yeah. > > I think the behavior should be tunable (ovl page cache vs. upper page > cache), at least initially, so it can be benchmarked in various > situations to see if there are no slowdowns with the new code. > Now the real fun begins... choosing the config option name ;-) Thanks, Amir.
