On Wed, 3 Aug 2016, Marc MERLIN wrote: > On Wed, Aug 03, 2016 at 07:44:41PM -0700, Eric Wheeler wrote: > > > When you say do "that" do you mean `trigger_gc` ? > > > > > > I think trigger_gc a cache thing, but the whole bcacheN dev might need to > > > be online before it can be triggered (not sure). Backing devices really > > > have metadata, just superblock. > > > > I meant to say: > > > > Backing devices have no metadata, just superblock. > > Mmmh, doing this just killed my cache: > saruman:/sys/block/bcache0# echo 1 > /sys/fs/bcache/7f2e1508-8db6-48cb-85d6-606c88f81f63/internal/trigger_gc > > [ 1639.204612] bcache: error on fc8cd783-346b-48f5-a619-fb0380584aa9: key too stale: 97, need_gc 97, disabling caching > [ 1639.204625] CPU: 7 PID: 519 Comm: bcache_gc Tainted: G W OE 4.4.5-amd64-volpreempt-sysrq-20160312bc5 #10 > [ 1639.204627] Hardware name: LENOVO 20ERCTO1WW/20ERCTO1WW, BIOS N1DET41W (1.15 ) 12/31/2015 > [ 1639.204629] 0000000000000000 ffff8808781fbbc0 ffffffff8134d88e ffff880875040ab8 > [ 1639.204635] ffff88087a3edcd0 ffff8808781fbc00 ffffffffc03b8609 0000000000000001 > [ 1639.204639] ffff880875040ab8 ffffffffc03b17ed ffff88087a3edcd0 ffff8808781fbc50 > [ 1639.204644] Call Trace: > [ 1639.204649] [<ffffffff8134d88e>] dump_stack+0x61/0x7d > [ 1639.204668] [<ffffffffc03b8609>] bch_extent_bad+0xd7/0x12b [bcache] > [ 1639.204677] [<ffffffffc03b17ed>] ? bch_ptr_invalid+0xc/0xc [bcache] > [ 1639.204684] [<ffffffffc03b17f7>] bch_ptr_bad+0xa/0xc [bcache] It seems that you've hit something that might not be a bug. This looks like disk corruption somehow from the looks of the backtrace. Maybe a failed on-SSD writeback flush, writeback controller flush (if any), or just erase block wearout. A quick google shows the last person to have this was in writethrough and rebuilt their cache back in 3.11->3.14: http://www.spinics.net/lists/linux-bcache/msg02450.html This looks like a better thread, possibly implicating TRIM: https://www.mail-archive.com/linux-bcache@xxxxxxxxxxxxxxx/msg02720.html If you are writeback, then maybe you could disable gc. I don't think there's a way to disable gc via sysfs, but you could try to comment this out: drivers/md/bcache/super.c: 1669 if (bch_gc_thread_start(c)) 1670 goto err; If it still functions (no idea, it might fail in other unexpected ways), then perhaps you can detach your cache and get it to writeback. > [ 1639.204690] [<ffffffffc03b1646>] bch_btree_iter_next_filter+0x32/0x42 [bcache] > [ 1639.204695] [<ffffffffc03b1ce2>] btree_gc_count_keys+0x3b/0x59 [bcache] > [ 1639.204701] [<ffffffffc03b5e44>] btree_gc_recurse+0x11b/0x2db [bcache] > [ 1639.204705] [<ffffffff8164ad9b>] ? __schedule+0x3b1/0x575 > [ 1639.204710] [<ffffffffc03b27e5>] ? __bch_btree_mark_key+0xba/0x1a4 [bcache] > [ 1639.204716] [<ffffffffc03b63c9>] bch_btree_gc+0x246/0x3cc [bcache] > [ 1639.204722] [<ffffffffc03b63c9>] ? bch_btree_gc+0x246/0x3cc [bcache] > [ 1639.204725] [<ffffffff8108d0f8>] ? wake_up_atomic_t+0x2c/0x2c > [ 1639.204731] [<ffffffffc03b6586>] bch_gc_thread+0x37/0xea [bcache] > [ 1639.204736] [<ffffffffc03b654f>] ? bch_btree_gc+0x3cc/0x3cc [bcache] > [ 1639.204741] [<ffffffffc03b654f>] ? bch_btree_gc+0x3cc/0x3cc [bcache] > [ 1639.204745] [<ffffffff81075c36>] kthread+0xa5/0xad > [ 1639.204747] [<ffffffff81075b91>] ? kthread_parkme+0x24/0x24 > [ 1639.204750] [<ffffffff8164decf>] ret_from_fork+0x3f/0x70 > [ 1639.204752] [<ffffffff81075b91>] ? kthread_parkme+0x24/0x24 > [ 1639.246944] bcache: cache_set_free() Cache set fc8cd783-346b-48f5-a619-fb0380584aa9 unregistered -- Eric Wheeler > > That's not good. > > What should I do now? > > Marc > -- > "A mouse is a device used to point at the xterm you want to type in" - A.S.R. > Microsoft is to operating systems .... > .... what McDonalds is to gourmet cooking > Home page: http://marc.merlins.org/ > -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
