On Fri, Jan 16, 2015 at 8:27 AM, Yan, Zheng <ukernel@xxxxxxxxx> wrote: > On Fri, Jan 16, 2015 at 2:37 PM, Gregory Farnum <greg@xxxxxxxxxxx> wrote: >> On Thu, Jan 15, 2015 at 2:44 PM, Michael Sevilla <mikesevilla3@xxxxxxxxx> wrote: >>> Let me know if this works and/or you need anything else: >>> >>> https://www.dropbox.com/s/fq47w6jebnyluu0/lookup-logs.tar.gz?dl=0 >>> >>> Beware - the clients were on debug=10. Also, I tried this with the >>> kernel client and it is more consistent; it does the 2 lookups per >>> create on 1 client every single time. >> >> Mmmm, there are no mds logs of note here. :( >> >> I did look enough to see that: >> 1) The MDS is for some reason revoking caps on the file create >> prompting the switch to double-lookups, which it was not before. The >> client doesn't really have any visibility into why that would be the >> case; the best guess I can come up with is that maybe the MDS split up >> the directory into multiple frags at this point -- do you have that >> enabled? >> 2) The only way we set the I_COMPLETE flag is when we create an empty >> directory, or when we do a complete listdir on one. That makes it >> pretty difficult to get the flag back (and so do the optimal create >> path) once you lose it. :( I'd love a better way to do so, but we'll >> have to look at what's involved in a bit of depth. >> >> I'm not sure why the kernel client is so much more cautious, but I >> think there were a number of troubles with the directory listing >> orders and things which were harder to solve there - I don't remember >> if we introduced the I_DIR_ORDERED flag in it or not. Zheng can talk >> more about that. What kernel client version are you using? >> >> And for a vanity data point, what kind of hardware is your MDS running on? :) > > For kernel before 3.18, the I_COMPLETE get cleared once directory is modified. > I_DIR_ORDERED is introduced by 3.18 kernel. I just tried 3.18 kernel, > unfortunately > there still is a bug that prevent new directory from having I_COMPLETE flag > Ok, I'll stay on 3.4 until that I_COMPLETE flag bug is fixed. Thanks! > Regards > Yan, Zheng > >> >> -Greg >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
