Hi Mark, Could you do below when the hang happens, and post the dmesg. echo w > /proc/sysrq-trigger 2016-01-04 9:35 GMT+01:00 Mark Zealey <mark@xxxxxxxxxxxxxxxxx>: > Hi there, I've run into a very strange hang with btrfs. I was trying to > restore a directory (postgres database) from a readonly snapshot. To do this > i used the command `cp -ar --reflink=always`. This worked fine for 100s of > files, however when it got to a particular file 16 kworker threads (I have 8 > processors in this system) got marked as being in D state (with 0 cpu usage > or disk usage) and I could not access the btrfs file system any more. I > can't see any kernel message or OOPS. Can you please let me know what > additional debug information I can provide to help track this issue down in > the kernel? > > System is latest ubuntu 14.04 LTS with a backported wily kernel (package > linux-image-4.2.0-22-generic): > > 4.2.0-22-generic #27~14.04.1-Ubuntu SMP Fri Dec 18 10:57:53 UTC 2015 x86_64 > x86_64 x86_64 GNU/Linux > > Thanks > > Mark > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" 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 linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
