Why are these operations not included in bindfs?

[maruhan2]

The following list,

flush, opendir, readdir, releasedir, fsyncdir, bmap, poll, write_buf, read_buf, fallocate,

are not defined. I'm sure they are omitted on purpose, but I'm not sure why.

[mpartel]

Thanks for bringing these up. TL;DR: some of them are unnecessary but some would certainly be useful to implement. I might do so later this week, but PRs are also welcome. If you feel like adding some of these, please let me know so I won't duplicate your work.

• flush: bindfs doesn't cache writes so there should be nothing to do here, I think. I might be wrong though.
• readdir is implemented
• opendir, releasedir: bindfs doesn't need to do anything in these. See readdir's implementation and see the comments on readdir in fuse.h. If we were to implement fsyncdir then these might become necessary.
• fsyncdir could be implemented. I noticed the passthrough examples that come with fuse don't implement it for some reason.
• bmap: The comment in fuse.h says: "This makes sense only for block device backed filesystems mounted with the 'blkdev' option" and bindfs is not backed by a block device.
• poll could be implemented. This wasn't in fuse when bindfs was originally implemented, and it's also not in the passthrough examples, so I missed it. I wonder what the default behaviour is.
• write_buf and read_buf: these are also fairly new. They look like optimizations of write() and read(). I'm not sure how much of a speedup they offer but I'd accept a PR for them if someone finds them useful.
• fallocate: again a fairly new function that might be useful to someone. Probably not used very often, and not all underlying filesystems support this, but should be easy to implement.

[maruhan2]

Ok thanks. I'm trying to build something for production based off your code base, and so I'll probably research those eventually (but probably not within at least 3 months), so I'll let you know if I get to it.