On Thu, Aug 24, 2017 at 05:13:54PM -0700, Dan Williams wrote: > > So this behaves differently than ext4 that returns EOPNOTSUP in the !DAX case. > > Are we generally documenting MAP_SYNC to be ignored in the pagecache > case? Or should we explicitly fail MAP_SYNC for the !DAX case on all > filesystems? It's just me being lazy for now until we've settled on the exact mmap interface. With your new ->mmap signature we can do proper flags checking, and I would add it. But with only Jans patches it seems like we'd silently support MAP_SYNC for all other file systems anyway. > Another option is to finish block allocations at fault time in the > pagecache+MAP_SYNC case, but still require fsync to writeback dirty > pages, but that seems pointless. Agreed. > Whatever we do I think all implementations should agree. Sure.
