Sunil Mushran wrote: ... >>> While I'm writing, here's one high-level question for you. >>> When would your new --fiemap-sync option be useful, and what change >>> in semantics will I see between when I use it and when I don't? >>> >>> --fiemap-sync sync file data before fiemap\n\ >>> >> IMHO, there is no difference from the user's point of view with or without >> this option. >> and on the kernel side, if FIEMAP_FLAG_SYNC was specified, it just do the >> dirty page process >> regardless of the sync succeeds or failed due to ENOSPC or EIO or other >> errors. >> >> I need to do more investigation to answer this question. > > I would recommend using fiemap purely as a means to get the extent map to > skip reading the holes when copying. That's it. And it should be used when > available. No user options.
I agree. Using fiemap is an optimization. Enable it if possible, otherwise, work as usual. No need for any change in the command-line interface. Jeff, please eliminate both --fiemap and --fiemap-sync in your next iteration. If someone makes a good case for exposing a fiemap-related option, we can always add it later.
