On Fri, Dec 2, 2016 at 1:36 PM, Blake Lewis <bl...@portworx.com> wrote: > Well, 3.10 is what you get with the RHEL7.x distributions, so that's > why people are running it. > Apparently, it is "good enough" for many purposes.
Nope. Btrfs in RHEL 7 is a technology preview, and ... "Technology Preview features are currently unsupported, may not be functionally complete, and are not suitable for deployment in production. " > My real goal here is to understand the scope of the bug and whether > any mitigation is > possible. Of course, I don't expect anyone else to make a patch for > me (or even to accept > my patch), but if I knew what the bug is and what was done to fix it, > I'd be in a much better > position to decide what to do. If anyone can shed any light on this, > I'd be very grateful. https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/diff/?id=v4.8.12&id2=v3.19&dt=2 There's more than 10000 lines changed between 3.19 and 4.8.12. You're in the right place, but it's a shot in the dark if any developer remembers the particular problem you're having compared to the massive pile of bugs fixed and changes made since then. The RHEL 3.10 kernel as I understand it has v3.19 Btrfs code. You might test with a 4.1.36 kernel to see if your problem reproduces. There was some O_DIRECTbug fixes a while back but I have no idea what kernel versions those were. If the fix is relatively recent, it simply may not have been backported very far because kernels go EOL and backporting just doesn't happen, not that it can't be done. So you might search the list for O_DIRECT, and see if anything looks familiar. If that doesn't pan out you can start doing simple bisects with longterm kernel.org kernels, starting with the oldest (which is where I got 4.1.36) and see if you can find a commit that fixes the problem, and then if it applies cleanly to the much older kernel you're using. -- Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
