J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > > Fixing this requires a much bigger overhaul of cachefiles than this patchset > > performs. > > That sounds like "sometimes you may get file corruption and there's > nothing you can do about it". But I know people actually use fscache, > so it must be reliable at least for some use cases. Yes. That's true for the upstream code because that uses bmap. I'm switching to use SEEK_HOLE/SEEK_DATA to get rid of the bmap usage, but it doesn't change the issue. > Is it that those "bridging" blocks only show up in certain corner cases > that users can arrange to avoid? Or that it's OK as long as you use > certain specific file systems whose behavior goes beyond what's > technically required by the bamp or seek interfaces? That's a question for the xfs, ext4 and btrfs maintainers, and may vary between kernel versions and fsck or filesystem packing utility versions. David