Viewing profile — josefbacik

I’m framing this comment and putting it on my wall in my office.

Keep in mind most of us don’t use our @fb.com addresses. LWN keeps track of companies by keeping track of who works where so our numbers are much higher than this list shows.

Agreed, drive managed is far better from a usability standpoint.

Host managed also means messing with the file system, and the patch set for btrfs is not small. Plus you have to disable a bunch of features (like preallocation since you can’t mov…

Not sure what you are talking about, it’s definitely endian neutral. You can’t take different page sized fs and put it on another page size arch, but that’s a separate issue.

Cause it’s a summit to talk about the whole ecosystem, not one file system. We btrfs developers talk enough to each other, we don’t need to bore the rest of the attendees with our …

It would be nice, but for complicated systems in the kernel you sometimes have to provide evidence that the old way sucks and the new way is better. With this work we can easily po…

I spent an unreasonable amount of time working on grub2. The stuff I looked at the most where the uefi spec http://wiki.phoenix.com/wiki/index.php/Category:UEFI And then the uefi s…

Lol what? We don't ship code that isn't upstream. It sucks to maintain and rebase if you have a shitton of proprietary patches. Everything we do with the kernel is open source, you…

Facebook is using it for lots of shit. Chroots for containers because we can easily snapshot them and use them. Use it for build testing, so snapshot base repo, checkout commit, bu…

A Linux file system developer in theory, a "this is broken and is in/related to the kernel" developer in practice.

Sendfile isn't async, it just avoids the user space copy, and in some cases the copy from the fd to the socket. Aio doesn't require xfs, just O_DIRECT, which can be tricky to get r…

All this talk about Oracle is just plain stupid. Oracle doesn't control anything, the community does. One core developer still works on Btrfs from Oracle, the vast majority of the …

Nope I love Red Hat and loved working for Red Hat and still interact with most of my colleagues there on a day to day basis. I shouldn't be speaking for everybody, but from what I …

They brought on Zach right before I left specifically to help with the effort, but he left as well. I can't really speak to Red Hat's overall strategic decisions, but really they h…

People are making a bigger deal of this than it is. Since I left Red Hat in 2012 there hasn't been another engineer to pick up the work, and it is _a lot_ of work. For RHEL you are…

Or I just mistyped and you are reading in too much to it?

Systemtap was fantastic, but super finnicky. You had to have debuginfo for the kernel installed plus the source. This was fine for RHEL but kind of a pain elsewhere. Then you run i…

You are confusing hardlinks with symlinks. They are similar but not the same. Symlinks in Linux most certainly get their own inode and can contain data blocks.

Symlinks are implemented as files in Linux, we write the path into the file that you are pointing to, so there most certainly is data that must be fsync()'ed if you want it to be p…

The rename is atomic, the data being in the file is the problem, there is no garuntee unless you fsync.

This is just an accident of how some file systems are implemented and isn't actually garunteed. If you did this on xfs you could still end up with the a 0 length symlink if you cra…

We have to look up the physical extent in the extent reference tree, so the cost is independent of the number of snapshots and more a function of the fragmentation of the extent tr…

Yeah nocow only works if there are no snapshots, which is why we have to check, so if you use snapshots it falls back to COW.