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 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
