On 01/29/2016 06:47 PM, Dr. David Alan Gilbert wrote: > * Wen Congyang (we...@cn.fujitsu.com) wrote: >> On 01/29/2016 06:07 PM, Dr. David Alan Gilbert wrote: >>> * Wen Congyang (we...@cn.fujitsu.com) wrote: >>>> On 01/27/2016 07:03 PM, Dr. David Alan Gilbert wrote: >>>>> Hi, >>>>> I've got a block error if I kill the secondary. >>>>> >>>>> Start both primary & secondary >>>>> kill -9 secondary qemu >>>>> x_colo_lost_heartbeat on primary >>>>> >>>>> The guest sees a block error and the ext4 root switches to read-only. >>>>> >>>>> I gdb'd the primary with a breakpoint on quorum_report_bad; see >>>>> backtrace below. >>>>> (This is based on colo-v2.4-periodic-mode of the framework >>>>> code with the block and network proxy merged in; so it could be my >>>>> merging but I don't think so ?) >>>>> >>>>> >>>>> (gdb) where >>>>> #0 quorum_report_bad (node_name=0x7f2946a0892c "node0", ret=-5, >>>>> acb=0x7f2946cb3910, acb=0x7f2946cb3910) >>>>> at /root/colo/jan-2016/qemu/block/quorum.c:222 >>>>> #1 0x00007f2943b23058 in quorum_aio_cb (opaque=<optimized out>, >>>>> ret=<optimized out>) >>>>> at /root/colo/jan-2016/qemu/block/quorum.c:315 >>>>> #2 0x00007f2943b311be in bdrv_co_complete (acb=0x7f2946cb3f60) at >>>>> /root/colo/jan-2016/qemu/block/io.c:2122 >>>>> #3 0x00007f2943ae777d in aio_bh_call (bh=<optimized out>) at >>>>> /root/colo/jan-2016/qemu/async.c:64 >>>>> #4 aio_bh_poll (ctx=ctx@entry=0x7f2945b771d0) at >>>>> /root/colo/jan-2016/qemu/async.c:92 >>>>> #5 0x00007f2943af5090 in aio_dispatch (ctx=0x7f2945b771d0) at >>>>> /root/colo/jan-2016/qemu/aio-posix.c:305 >>>>> #6 0x00007f2943ae756e in aio_ctx_dispatch (source=<optimized out>, >>>>> callback=<optimized out>, >>>>> user_data=<optimized out>) at /root/colo/jan-2016/qemu/async.c:231 >>>>> #7 0x00007f293b84a79a in g_main_context_dispatch () from >>>>> /lib64/libglib-2.0.so.0 >>>>> #8 0x00007f2943af3a00 in glib_pollfds_poll () at >>>>> /root/colo/jan-2016/qemu/main-loop.c:211 >>>>> #9 os_host_main_loop_wait (timeout=<optimized out>) at >>>>> /root/colo/jan-2016/qemu/main-loop.c:256 >>>>> #10 main_loop_wait (nonblocking=<optimized out>) at >>>>> /root/colo/jan-2016/qemu/main-loop.c:504 >>>>> #11 0x00007f29438529ee in main_loop () at >>>>> /root/colo/jan-2016/qemu/vl.c:1945 >>>>> #12 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized >>>>> out>) at /root/colo/jan-2016/qemu/vl.c:4707 >>>>> >>>>> (gdb) p s->num_children >>>>> $1 = 2 >>>>> (gdb) p acb->success_count >>>>> $2 = 0 >>>>> (gdb) p acb->is_read >>>>> $5 = false >>>> >>>> Sorry for the late reply. >>> >>> No problem. >>> >>>> What it the value of acb->count? >>> >>> (gdb) p acb->count >>> $1 = 1 >> >> Note, the count is 1, not 2. Writing to children.0 is in flight. If writing >> to children.0 successes, >> the guest doesn't know this error. >>>> If secondary host is down, you should remove quorum's children.1. >>>> Otherwise, you will get >>>> I/O error event. >>> >>> Is that safe? If the secondary fails, do you always have time to issue the >>> command to >>> remove the children.1 before the guest sees the error? >> >> We will write to two children, and expect that writing to children.0 will >> success. If so, >> the guest doesn't know this error. You just get the I/O error event. > > I think children.0 is the disk, and that should be OK - so only the > children.1/replication should > be failing - so in that case why do I see the error?
I don't know, and I will check the codes. > The 'node0' in the backtrace above is the name of the replication, so it does > look like the error > is coming from the replication. No, the backtrace is just report an I/O error events to the management application. > >>> Anyway, I tried removing children.1 but it segfaults now, I guess the >>> replication is unhappy: >>> >>> (qemu) x_block_change colo-disk0 -d children.1 >>> (qemu) x_colo_lost_heartbeat >> >> Hmm, you should not remove the child before failover. I will check it how to >> avoid it in the codes. > > But you said 'If secondary host is down, you should remove quorum's > children.1' - is that not > what you meant? Yes, you should excute 'x_colo_lost_heartbeat' fist, and then excute 'x_block_change ... -d ...'. > >>> 12973 Segmentation fault (core dumped) >>> ./try/x86_64-softmmu/qemu-system-x86_64 -enable-kvm $console_param -S -boot >>> c -m 4080 -smp 4 -machine pc-i440fx-2.5,accel=kvm -name debug-threads=on >>> -trace events=trace-file -device virtio-rng-pci $block_param $net_param >>> >>> #0 0x00007f0a398a864c in bdrv_stop_replication (bs=0x7f0a3b0a8430, >>> failover=true, errp=0x7fff6a5c3420) >>> at /root/colo/jan-2016/qemu/block.c:4426 >>> >>> (gdb) p drv >>> $1 = (BlockDriver *) 0x5d2a >>> >>> it looks like the whole of bs is bogus. >>> >>> #1 0x00007f0a398d87f6 in quorum_stop_replication (bs=<optimized out>, >>> failover=<optimized out>, >>> errp=<optimized out>) at /root/colo/jan-2016/qemu/block/quorum.c:1213 >>> >>> (gdb) p s->replication_index >>> $3 = 1 >>> >>> I guess quorum_del_child needs to stop replication before it removes the >>> child? >> >> Yes, but in the newest version, quorum doesn't know the block replication, >> and I think >> we shoud add an reference to the bs when starting block replication. > > Do you have a new version ready to test? I'm interested to try it (and also > interested > to try the latest version of the colo-proxy) I think we can post the newest version this week. Thanks Wen Congyang > > Dave > >> Thanks >> Wen Congyang >> >>> (although it would have to be careful not to block on the dead nbd). >>> >>> #2 0x00007f0a398a8901 in bdrv_stop_replication_all >>> (failover=failover@entry=true, errp=errp@entry=0x7fff6a5c3478) >>> at /root/colo/jan-2016/qemu/block.c:4504 >>> #3 0x00007f0a3984b0af in primary_vm_do_failover () at >>> /root/colo/jan-2016/qemu/migration/colo.c:144 >>> #4 colo_do_failover (s=<optimized out>) at >>> /root/colo/jan-2016/qemu/migration/colo.c:162 >>> #5 0x00007f0a3989d7fd in aio_bh_call (bh=<optimized out>) at >>> /root/colo/jan-2016/qemu/async.c:64 >>> #6 aio_bh_poll (ctx=ctx@entry=0x7f0a3a6c21d0) at >>> /root/colo/jan-2016/qemu/async.c:92 >>> #7 0x00007f0a398ab110 in aio_dispatch (ctx=0x7f0a3a6c21d0) at >>> /root/colo/jan-2016/qemu/aio-posix.c:305 >>> #8 0x00007f0a3989d5ee in aio_ctx_dispatch (source=<optimized out>, >>> callback=<optimized out>, >>> user_data=<optimized out>) at /root/colo/jan-2016/qemu/async.c:231 >>> #9 0x00007f0a3160079a in g_main_context_dispatch () from >>> /lib64/libglib-2.0.so.0 >>> #10 0x00007f0a398a9a80 in glib_pollfds_poll () at >>> /root/colo/jan-2016/qemu/main-loop.c:211 >>> #11 os_host_main_loop_wait (timeout=<optimized out>) at >>> /root/colo/jan-2016/qemu/main-loop.c:256 >>> #12 main_loop_wait (nonblocking=<optimized out>) at >>> /root/colo/jan-2016/qemu/main-loop.c:504 >>> #13 0x00007f0a396089ee in main_loop () at /root/colo/jan-2016/qemu/vl.c:1945 >>> #14 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) >>> at /root/colo/jan-2016/qemu/vl.c:4707 >>> >>> Dave >>> >>>> Thanks >>>> Wen Congyang >>>> >>>>> >>>>> (qemu) info block >>>>> colo-disk0 (#block080): json:{"children": [{"driver": "raw", "file": >>>>> {"driver": "file", "filename": "/root/colo/bugzilla.raw"}}, {"driver": >>>>> "replication", "mode": "primary", "file": {"port": "8889", "host": >>>>> "ibpair", "driver": "nbd", "export": "colo-disk0"}}], "driver": "quorum", >>>>> "blkverify": false, "rewrite-corrupted": false, "vote-threshold": 1} >>>>> (quorum) >>>>> Cache mode: writeback, direct >>>>> >>>>> Dave >>>>> >>>>> * Changlong Xie (xiecl.f...@cn.fujitsu.com) wrote: >>>>>> Block replication is a very important feature which is used for >>>>>> continuous checkpoints(for example: COLO). >>>>>> >>>>>> You can get the detailed information about block replication from here: >>>>>> http://wiki.qemu.org/Features/BlockReplication >>>>>> >>>>>> Usage: >>>>>> Please refer to docs/block-replication.txt >>>>>> >>>>>> This patch series is based on the following patch series: >>>>>> 1. http://lists.nongnu.org/archive/html/qemu-devel/2015-12/msg04570.html >>>>>> >>>>>> You can get the patch here: >>>>>> https://github.com/Pating/qemu/tree/changlox/block-replication-v13 >>>>>> >>>>>> You can get the patch with framework here: >>>>>> https://github.com/Pating/qemu/tree/changlox/colo_framework_v12 >>>>>> >>>>>> TODO: >>>>>> 1. Continuous block replication. It will be started after basic functions >>>>>> are accepted. >>>>>> >>>>>> Changs Log: >>>>>> V13: >>>>>> 1. Rebase to the newest codes >>>>>> 2. Remove redundant marcos and semicolon in replication.c >>>>>> 3. Fix typos in block-replication.txt >>>>>> V12: >>>>>> 1. Rebase to the newest codes >>>>>> 2. Use backing reference to replcace 'allow-write-backing-file' >>>>>> V11: >>>>>> 1. Reopen the backing file when starting blcok replication if it is not >>>>>> opened in R/W mode >>>>>> 2. Unblock BLOCK_OP_TYPE_BACKUP_SOURCE and BLOCK_OP_TYPE_BACKUP_TARGET >>>>>> when opening backing file >>>>>> 3. Block the top BDS so there is only one block job for the top BDS and >>>>>> its backing chain. >>>>>> V10: >>>>>> 1. Use blockdev-remove-medium and blockdev-insert-medium to replace >>>>>> backing >>>>>> reference. >>>>>> 2. Address the comments from Eric Blake >>>>>> V9: >>>>>> 1. Update the error messages >>>>>> 2. Rebase to the newest qemu >>>>>> 3. Split child add/delete support. These patches are sent in another >>>>>> patchset. >>>>>> V8: >>>>>> 1. Address Alberto Garcia's comments >>>>>> V7: >>>>>> 1. Implement adding/removing quorum child. Remove the option non-connect. >>>>>> 2. Simplify the backing refrence option according to Stefan Hajnoczi's >>>>>> suggestion >>>>>> V6: >>>>>> 1. Rebase to the newest qemu. >>>>>> V5: >>>>>> 1. Address the comments from Gong Lei >>>>>> 2. Speed the failover up. The secondary vm can take over very quickly >>>>>> even >>>>>> if there are too many I/O requests. >>>>>> V4: >>>>>> 1. Introduce a new driver replication to avoid touch nbd and qcow2. >>>>>> V3: >>>>>> 1: use error_setg() instead of error_set() >>>>>> 2. Add a new block job API >>>>>> 3. Active disk, hidden disk and nbd target uses the same AioContext >>>>>> 4. Add a testcase to test new hbitmap API >>>>>> V2: >>>>>> 1. Redesign the secondary qemu(use image-fleecing) >>>>>> 2. Use Error objects to return error message >>>>>> 3. Address the comments from Max Reitz and Eric Blake >>>>>> >>>>>> Wen Congyang (10): >>>>>> unblock backup operations in backing file >>>>>> Store parent BDS in BdrvChild >>>>>> Backup: clear all bitmap when doing block checkpoint >>>>>> Allow creating backup jobs when opening BDS >>>>>> docs: block replication's description >>>>>> Add new block driver interfaces to control block replication >>>>>> quorum: implement block driver interfaces for block replication >>>>>> Implement new driver for block replication >>>>>> support replication driver in blockdev-add >>>>>> Add a new API to start/stop replication, do checkpoint to all BDSes >>>>>> >>>>>> block.c | 145 ++++++++++++ >>>>>> block/Makefile.objs | 3 +- >>>>>> block/backup.c | 14 ++ >>>>>> block/quorum.c | 78 +++++++ >>>>>> block/replication.c | 545 >>>>>> +++++++++++++++++++++++++++++++++++++++++++++ >>>>>> blockjob.c | 11 + >>>>>> docs/block-replication.txt | 227 +++++++++++++++++++ >>>>>> include/block/block.h | 9 + >>>>>> include/block/block_int.h | 15 ++ >>>>>> include/block/blockjob.h | 12 + >>>>>> qapi/block-core.json | 33 ++- >>>>>> 11 files changed, 1089 insertions(+), 3 deletions(-) >>>>>> create mode 100644 block/replication.c >>>>>> create mode 100644 docs/block-replication.txt >>>>>> >>>>>> -- >>>>>> 1.9.3 >>>>>> >>>>>> >>>>>> >>>>> -- >>>>> Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK >>>>> >>>>> >>>>> . >>>>> >>>> >>>> >>>> >>> -- >>> Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK >>> >>> >>> . >>> >> >> >> > -- > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > > > . >