From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40943) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7Rnb-0001M1-Hg for qemu-devel@nongnu.org; Mon, 30 May 2016 14:20:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b7RnY-00044j-7T for qemu-devel@nongnu.org; Mon, 30 May 2016 14:20:23 -0400 Date: Mon, 30 May 2016 11:20:16 -0700 From: Stefan Hajnoczi Message-ID: <20160530182016.GC1366@stefanha-x1.localdomain> References: <1463729780-31982-1-git-send-email-xiecl.fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ghzN8eJ9Qlbqn3iT" Content-Disposition: inline In-Reply-To: <1463729780-31982-1-git-send-email-xiecl.fnst@cn.fujitsu.com> Subject: Re: [Qemu-devel] [Qemu-block] [PATCH v19 00/10] Block replication for continuous checkpoints List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Changlong Xie Cc: qemu devel , Stefan Hajnoczi , Fam Zheng , Max Reitz , Kevin Wolf , Jeff Cody , Wen Congyang , zhanghailiang , qemu block , Jiang Yunhong , Dong Eddie , "Dr. David Alan Gilbert" , Markus Armbruster , Gonglei , Paolo Bonzini --ghzN8eJ9Qlbqn3iT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 20, 2016 at 03:36:10PM +0800, Changlong Xie wrote: > Block replication is a very important feature which is used for > continuous checkpoints(for example: COLO). >=20 > You can get the detailed information about block replication from here: > http://wiki.qemu.org/Features/BlockReplication >=20 > Usage: > Please refer to docs/block-replication.txt >=20 > You can get the patch here: > https://github.com/Pating/qemu/tree/changlox/block-replication-v19 >=20 > You can get the patch with framework here: > https://github.com/Pating/qemu/tree/changlox/colo_framework_v18 >=20 > TODO: > 1. Continuous block replication. It will be started after basic functions > are accepted. >=20 > Changs Log: > V19: > 1. Rebase to v2.6.0 > 2. Address comments from stefan > p3: a new patch that export interfaces for extra serialization > p8:=20 > 1. call replication_stop() before freeing s->top_id > 2. check top_bs > 3. reopen file readonly in error return paths > 4. enable extra serialization between read and COW > p9: try to hanlde SIGABRT > V18: > p6: add local_err in all replication callbacks to prevent "errp =3D=3D NU= LL" > p7: add missing qemu_iovec_destroy(xxx) > V17: > 1. Rebase to the lastest codes=20 > p2: refactor backup_do_checkpoint addressed comments from Jeff Cody > p4: fix bugs in "drive_add buddy xxx" hmp commands > p6: add "since: 2.7" > p7: fix bug in replication_close(), add missing "qapi/error.h", add test-= replication=20 > p8: add "since: 2.7" > V16: > 1. Rebase to the newest codes > 2. Address comments from Stefan & hailiang > p3: we don't need this patch now > p4: add "top-id" parameters for secondary > p6: fix NULL pointer in replication callbacks, remove unnecessary typedef= s,=20 > add doc comments that explain the semantics of Replication > p7: Refactor AioContext for thread-safe, remove unnecessary get_top_bs() > *Note*: I'm working on replication testcase now, will send out in V17 > V15: > 1. Rebase to the newest codes > 2. Fix typos and coding style addresed Eric's comments > 3. Address Stefan's comments > 1) Make backup_do_checkpoint public, drop the changes on BlockJobDriver > 2) Update the message and description for [PATCH 4/9] > 3) Make replication_(start/stop/do_checkpoint)_all as global interfaces > 4) Introduce AioContext lock to protect start/stop/do_checkpoint callb= acks > 5) Use BdrvChild instead of holding on to BlockDriverState * pointers > 4. Clear BDRV_O_INACTIVE for hidden disk's open_flags since commit 09e0c7= 71 =20 > 5. Introduce replication_get_error_all to check replication status > 6. Remove useless discard interface > V14: > 1. Implement auto complete active commit > 2. Implement active commit block job for replication.c > 3. Address the comments from Stefan, add replication-specific API and data > structure, also remove old block layer APIs > V13: > 1. Rebase to the newest codes > 2. Remove redundant marcos and semicolon in replication.c=20 > 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 backi= ng > 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 patc= hset. > 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 su= ggestion > 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 >=20 > Changlong Xie (3): > Backup: export interfaces for extra serialization > Introduce new APIs to do replication operation > tests: add unit test case for replication >=20 > Wen Congyang (7): > unblock backup operations in backing file > Backup: clear all bitmap when doing block checkpoint > Link backup into block core > docs: block replication's description > auto complete active commit > Implement new driver for block replication > support replication driver in blockdev-add >=20 > Makefile.objs | 1 + > block.c | 17 ++ > block/Makefile.objs | 3 +- > block/backup.c | 59 +++- > block/mirror.c | 13 +- > block/replication.c | 666 +++++++++++++++++++++++++++++++++++++= ++++++ > blockdev.c | 2 +- > docs/block-replication.txt | 239 ++++++++++++++++ > include/block/block_backup.h | 17 ++ > include/block/block_int.h | 3 +- > qapi/block-core.json | 33 ++- > qemu-img.c | 2 +- > replication.c | 105 +++++++ > replication.h | 176 ++++++++++++ > tests/.gitignore | 1 + > tests/Makefile | 4 + > tests/test-replication.c | 523 +++++++++++++++++++++++++++++++++ > 17 files changed, 1847 insertions(+), 17 deletions(-) > create mode 100644 block/replication.c > create mode 100644 docs/block-replication.txt > create mode 100644 include/block/block_backup.h > create mode 100644 replication.c > create mode 100644 replication.h > create mode 100644 tests/test-replication.c I have reviewed many revisions of this series. The main mechanism in this series makes sense to me. I'm still concerned that checkpointing (vm_stop(), not in this series but COLO in general) depends on bdrv_drain(), which can block forever if I/O is hung. That doesn't seem like a reasonable limitation for a high availability feature since it may lead to the VM becoming unavailable. I'd like Jeff and/or Kevin to review this series and merge it once they are happy. Stefan --ghzN8eJ9Qlbqn3iT Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJXTIRgAAoJEJykq7OBq3PILmoIALBBvcL+Y5aWz/yPE4uV0NO8 9X94zA+6NmZOLy8hyfE1OaxMojCBBjGGXsbYvxaznLHikTbQkwZyFowIr8HjRMCm XeDUMv/OMonnLYGeB94X7l0fVOvKGKruWzf4rXTjCKVaY6XHazawek1KQVRdK4cK YnPbfcnuFAWI39+PpBa5TEfQZWuFWSmxI4QJOzIJeqaMiA0zZvhY3xZyw4pYlZDL +fpiENME01gde2nd/7bIvq8cA7jdVX0pHWUeJJ9n3Yhib7bv+7L3EBWE69qsre3d Bmm2AGs1x6ecrQsUMu4O/zV2ZRrcSxlw1wYbda+MJnDaB+v/nyXjJwAHRyHKL90= =q38y -----END PGP SIGNATURE----- --ghzN8eJ9Qlbqn3iT--