qemu/block
Paolo Bonzini d42cf28837 block: change drain to look only at one child at a time
bdrv_requests_pending is checking children to also wait until internal
requests (such as metadata writes) have completed.  However, checking
children is in general overkill.  Children requests can be of two kinds:

- requests caused by an operation on bs, e.g. a bdrv_aio_write to bs
causing a write to bs->file->bs.  In this case, the parent's in_flight
count will always be incremented by at least one for every request in
the child.

- asynchronous metadata writes or flushes.  Such writes can be started
even if bs's in_flight count is zero, but not after the .bdrv_drain
callback has been invoked.

This patch therefore changes bdrv_drain to finish I/O in the parent
(after which the parent's in_flight will be locked to zero), call
bdrv_drain (after which the parent will not generate I/O on the child
anymore), and then wait for internal I/O in the children to complete.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-Id: <1477565348-5458-6-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
2016-10-28 21:50:18 +08:00
..
accounting.c block: Clean up includes 2016-01-20 13:36:23 +01:00
archipelago.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
backup.c blockjob: introduce .drain callback for jobs 2016-10-28 21:50:18 +08:00
blkdebug.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
blkreplay.c replay: allow replay stopping and restarting 2016-09-27 11:57:30 +02:00
blkverify.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
block-backend.c block: add BDS field to count in-flight requests 2016-10-28 21:50:18 +08:00
bochs.c block: Convert bdrv_co_preadv/pwritev to BdrvChild 2016-07-05 16:46:27 +02:00
cloop.c block: Convert bdrv_pread(v) to BdrvChild 2016-07-05 16:46:27 +02:00
commit.c commit: Add 'base' to the reopen queue before 'overlay_bs' 2016-09-23 13:36:10 +02:00
crypto.c crypto: make PBKDF iterations configurable for LUKS format 2016-09-19 16:30:45 +01:00
curl.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
dirty-bitmap.c block: More operations for meta dirty bitmap 2016-10-24 17:56:07 +02:00
dmg-bz2.c dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
dmg.c dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
dmg.h dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
gluster.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
io.c block: change drain to look only at one child at a time 2016-10-28 21:50:18 +08:00
iscsi.c block/iscsi: Adding new iSER transport layer option 2016-10-24 11:30:55 +02:00
linux-aio.c linux-aio: fix re-entrant completion processing 2016-09-28 17:11:23 +01:00
Makefile.objs dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
mirror.c mirror: use bdrv_drained_begin/bdrv_drained_end 2016-10-28 21:50:18 +08:00
nbd-client.c nbd: Convert to byte-based interface 2016-07-20 14:24:25 +01:00
nbd-client.h nbd: Limit nbdflags to 16 bits 2016-08-03 18:44:56 +02:00
nbd.c block/nbd: Use SocketAddress options 2016-10-27 19:05:23 +02:00
nfs.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
null.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
parallels.c block/parallels: check new image size 2016-08-05 09:59:06 +01:00
qapi.c qapi: rename QmpOutputVisitor to QObjectOutputVisitor 2016-10-25 16:25:54 +02:00
qcow2-cache.c block: Convert bdrv_pwrite(v/_sync) to BdrvChild 2016-07-05 16:46:27 +02:00
qcow2-cluster.c qcow2: Support BDRV_REQ_MAY_UNMAP 2016-10-24 17:54:03 +02:00
qcow2-refcount.c block: Convert bdrv_discard() to byte-based 2016-07-20 14:11:55 +01:00
qcow2-snapshot.c block: Convert bdrv_pwrite(v/_sync) to BdrvChild 2016-07-05 16:46:27 +02:00
qcow2.c qcow2: Support BDRV_REQ_MAY_UNMAP 2016-10-24 17:54:03 +02:00
qcow2.h qcow2: Support BDRV_REQ_MAY_UNMAP 2016-10-24 17:54:03 +02:00
qcow.c crypto: extend mode as a parameter in qcrypto_cipher_supports() 2016-10-19 10:09:24 +01:00
qed-check.c qed: Use DIV_ROUND_UP 2016-06-07 18:19:24 +03:00
qed-cluster.c block: Clean up includes 2016-01-20 13:36:23 +01:00
qed-gencb.c block: Clean up includes 2016-01-20 13:36:23 +01:00
qed-l2-cache.c block: Clean up includes 2016-01-20 13:36:23 +01:00
qed-table.c block: Convert bdrv_aio_writev() to BdrvChild 2016-07-05 16:46:26 +02:00
qed.c block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
qed.h block: use aio_bh_schedule_oneshot 2016-10-07 13:34:07 +02:00
quorum.c quorum: do not allocate multiple iovecs for FIFO strategy 2016-10-24 17:56:06 +02:00
raw_bsd.c raw: Implement .bdrv_co_ioctl instead of .bdrv_aio_ioctl 2016-10-27 19:05:23 +02:00
raw-posix.c raw-posix: Don't use bdrv_ioctl() 2016-10-27 19:05:23 +02:00
raw-win32.c block: improve error handling in raw_open 2016-10-24 17:54:03 +02:00
rbd.c rbd: shift byte count as a 64-bit value 2016-10-23 16:10:59 +02:00
replication.c replication: interrupt failover if the main device is closed 2016-10-28 21:50:18 +08:00
sheepdog.c sheepdog: remove useless casts 2016-09-15 15:32:22 +03:00
snapshot.c error: Remove NULL checks on error_propagate() calls 2016-06-20 16:38:13 +02:00
ssh.c block/ssh: Use QemuOpts for runtime options 2016-08-15 15:52:28 +02:00
stream.c Improve block job rate limiting for small bandwidth values 2016-07-13 13:41:38 +02:00
throttle-groups.c throttle: Correct access to wrong BlockBackendPublic structures 2016-10-24 17:54:03 +02:00
trace-events block: Remove bdrv_aio_pdiscard() 2016-10-27 19:05:22 +02:00
vdi.c vdi: Use QEMU UUID API 2016-09-23 11:42:52 +08:00
vhdx-endian.c vhdx: Use QEMU UUID API 2016-09-23 11:42:52 +08:00
vhdx-log.c block: Convert bdrv_pwrite(v/_sync) to BdrvChild 2016-07-05 16:46:27 +02:00
vhdx.c vhdx: Use QEMU UUID API 2016-09-23 11:42:52 +08:00
vhdx.h block: vhdx - update PAYLOAD_BLOCK_UNMAPPED value to match 1.00 spec 2014-12-12 15:42:22 +00:00
vmdk.c vmdk: add vmdk_co_pwritev_compressed 2016-09-05 19:06:48 +02:00
vpc.c vpc: Use QEMU UUID API 2016-09-23 11:42:52 +08:00
vvfat.c block: Add "read-only" to the options QDict 2016-09-23 13:36:10 +02:00
win32-aio.c linux-aio: share one LinuxAioState within an AioContext 2016-07-18 15:09:31 +01:00
write-threshold.c block: use bdrv_add_before_write_notifier 2016-10-07 13:34:07 +02:00