Max Reitz 5cb2737e92 block/io: Delay decrementing the quiesce_counter ... When ending a drained section, bdrv_do_drained_end() currently first decrements the quiesce_counter, and only then actually ends the drain. The bdrv_drain_invoke(bs, false) call may cause graph changes. Say the graph change involves replacing an existing BB's ("blk") BDS (blk_bs(blk)) by @bs. Let us introducing the following values: - bs_oqc = old_quiesce_counter (so bs->quiesce_counter == bs_oqc - 1) - obs_qc = blk_bs(blk)->quiesce_counter (before bdrv_drain_invoke()) Let us assume there is no blk_pread_unthrottled() involved, so blk->quiesce_counter == obs_qc (before bdrv_drain_invoke()). Now replacing blk_bs(blk) by @bs will reduce blk->quiesce_counter by obs_qc (making it 0) and increase it by bs_oqc-1 (making it bs_oqc-1). bdrv_drain_invoke() returns and we invoke bdrv_parent_drained_end(). This will decrement blk->quiesce_counter by one, so it would be -1 -- were there not an assertion against that in blk_root_drained_end(). We therefore have to keep the quiesce_counter up at least until bdrv_drain_invoke() returns, so that bdrv_parent_drained_end() does the right thing for the parents @bs got during bdrv_drain_invoke(). But let us delay it even further, namely until bdrv_parent_drained_end() returns, because then it mirrors bdrv_do_drained_begin(): There, we first increment the quiesce_counter, then begin draining the parents, and then call bdrv_drain_invoke(). It makes sense to let bdrv_do_drained_end() unravel this exactly in reverse. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>		2019-06-04 15:20:41 +02:00
..
accounting.c	block/accounting: introduce latency histogram	2018-03-19 14:58:37 -05:00
backup.c	block/backup: refactor: split out backup_calculate_cluster_size	2019-05-28 20:30:55 +02:00
blkdebug.c	block: Advertise BDRV_REQ_NO_FALLBACK in filter drivers	2019-03-26 11:37:51 +01:00
blklogwrites.c	block: Purify .bdrv_refresh_filename()	2019-02-25 15:11:27 +01:00
blkreplay.c	trivial: Make bios files and source files non-executable	2018-09-25 17:26:18 +02:00
blkverify.c	block: Purify .bdrv_refresh_filename()	2019-02-25 15:11:27 +01:00
block-backend.c	block: Make bdrv_root_attach_child() unref child_bs on failure	2019-05-28 20:30:55 +02:00
bochs.c	avoid TABs in files that only contain a few	2019-01-11 15:46:56 +01:00
cloop.c	block: Require auto-read-only for existing fallbacks	2018-11-05 15:09:55 +01:00
commit.c	commit: Use bdrv_append() in commit_start()	2019-05-07 17:14:21 +02:00
copy-on-read.c	block: Advertise BDRV_REQ_NO_FALLBACK in filter drivers	2019-03-26 11:37:51 +01:00
create.c	jobs: utilize job_exit shim	2018-08-31 16:28:33 +02:00
crypto.c	block: Make bdrv_{copy_on_read,crypto_luks,replication} static	2019-03-19 15:49:29 +01:00
crypto.h	Clean up ill-advised or unusual header guards	2019-05-13 08:58:55 +02:00
curl.c	block/curl: Implement bdrv_refresh_filename()	2019-02-25 15:11:27 +01:00
dirty-bitmap.c	qapi: support external bitmaps in block-dirty-bitmap-merge	2019-05-28 19:33:31 -04:00
dmg-bz2.c	dmg: Move libbz2 code to dmg-bz2.so	2016-10-07 14:14:06 +02:00
dmg-lzfse.c	block: adding lzfse decompressing support as a module.	2018-12-14 11:52:40 +01:00
dmg.c	dmg: don't skip zero chunk	2019-01-04 11:15:09 +00:00
dmg.h	dmg: including dmg-lzfse module inside dmg block driver.	2018-12-14 11:52:40 +01:00
file-posix.c	block/file-posix: Unaligned O_DIRECT block-status	2019-05-20 17:08:57 +02:00
file-win32.c	avoid TABs in files that only contain a few	2019-01-11 15:46:56 +01:00
gluster.c	block/gluster: limit the transfer size to 512 MiB	2019-04-02 12:04:44 +02:00
io.c	block/io: Delay decrementing the quiesce_counter	2019-06-04 15:20:41 +02:00
iscsi-opts.c	Move include qemu/option.h from qemu-common.h to actual users	2018-02-09 13:52:16 +01:00
iscsi.c	block/iscsi: Restrict Linux-specific code	2019-03-11 16:33:49 +01:00
linux-aio.c	avoid TABs in files that only contain a few	2019-01-11 15:46:56 +01:00
Makefile.objs	qcow2: add separate file for threaded data processing functions	2019-05-28 20:30:55 +02:00
mirror.c	blockjob: Propagate AioContext change to all job nodes	2019-05-20 17:08:56 +02:00
nbd-client.c	nbd/client: Trace server noncompliance on structured reads	2019-04-01 08:58:04 -05:00
nbd-client.h	nbd: Restrict connection_co reentrance	2019-02-25 15:03:19 +01:00
nbd.c	nbd/client: Lower min_block for block-status, unaligned size	2019-03-30 20:52:19 -05:00
nfs.c	block: Purify .bdrv_refresh_filename()	2019-02-25 15:11:27 +01:00
null.c	block/null: Generate filename even with latency-ns	2019-02-25 15:11:27 +01:00
nvme.c	block/nvme: Fix bdrv_refresh_filename()	2019-02-25 15:11:27 +01:00
parallels.c	block/parallels: use buffer-based io	2019-04-30 15:29:00 +02:00
parallels.h	Clean up includes	2018-02-09 05:05:11 +01:00
qapi.c	qemu-img: Saner printing of large file sizes	2019-04-30 15:29:00 +02:00
qcow2-bitmap.c	qcow2-bitmap: initialize bitmap directory alignment	2019-05-28 20:30:55 +02:00
qcow2-cache.c	qcow2.h: add missing include	2019-05-28 20:30:55 +02:00
qcow2-cluster.c	qcow2: skip writing zero buffers to empty COW areas	2019-05-28 20:30:55 +02:00
qcow2-refcount.c	block: avoid recursive block_status call if possible	2019-06-04 15:20:41 +02:00
qcow2-snapshot.c	qcow2.h: add missing include	2019-05-28 20:30:55 +02:00
qcow2-threads.c	qcow2: do encryption in threads	2019-05-28 20:30:55 +02:00
qcow2.c	block: avoid recursive block_status call if possible	2019-06-04 15:20:41 +02:00
qcow2.h	block: avoid recursive block_status call if possible	2019-06-04 15:20:41 +02:00
qcow.c	block/qcow: use buffer-based io	2019-04-30 15:29:00 +02:00
qed-check.c	block/qed: add missed coroutine_fn markers	2019-04-30 15:29:00 +02:00
qed-cluster.c	qed: protect table cache with CoMutex	2017-07-17 11:34:11 +08:00
qed-l2-cache.c	qed: protect table cache with CoMutex	2017-07-17 11:34:11 +08:00
qed-table.c	block/qed: add missed coroutine_fn markers	2019-04-30 15:29:00 +02:00
qed.c	block/qed: add missed coroutine_fn markers	2019-04-30 15:29:00 +02:00
qed.h	block/qed: add missed coroutine_fn markers	2019-04-30 15:29:00 +02:00
quorum.c	block: Make bdrv_root_attach_child() unref child_bs on failure	2019-05-28 20:30:55 +02:00
raw-format.c	block: Advertise BDRV_REQ_NO_FALLBACK in filter drivers	2019-03-26 11:37:51 +01:00
rbd.c	block: Add strong_runtime_opts to BlockDriver	2019-02-25 15:11:27 +01:00
replication.c	block: Make bdrv_{copy_on_read,crypto_luks,replication} static	2019-03-19 15:49:29 +01:00
sheepdog.c	block: Add strong_runtime_opts to BlockDriver	2019-02-25 15:11:27 +01:00
snapshot.c	block/snapshot: remove bdrv_snapshot_delete_by_id_or_name	2019-02-25 15:03:18 +01:00
ssh.c	block/ssh: Implement .bdrv_dirname()	2019-05-07 17:14:21 +02:00
stream.c	block/stream: use buffer-based io	2019-04-30 15:29:00 +02:00
throttle-groups.c	throttle-groups: fix restart coroutine iothread race	2019-01-24 10:02:28 +00:00
throttle.c	block: Add strong_runtime_opts to BlockDriver	2019-02-25 15:11:27 +01:00
trace-events	qcow2: skip writing zero buffers to empty COW areas	2019-05-28 20:30:55 +02:00
vdi.c	vdi: Replace bdrv_{read,write}() with bdrv_{pread,pwrite}()	2019-05-10 16:45:40 +02:00
vhdx-endian.c	block/vhdx: Don't take address of fields in packed structs	2018-11-05 15:09:54 +01:00
vhdx-log.c	block/vhdx: Use IEC binary prefixes for size constants	2019-04-30 15:29:00 +02:00
vhdx.c	block/vhdx: Use IEC binary prefixes for size constants	2019-04-30 15:29:00 +02:00
vhdx.h	block/vhdx: Use IEC binary prefixes for size constants	2019-04-30 15:29:00 +02:00
vmdk.c	vmdk: Set vmdk parent backing_format to vmdk	2019-04-30 15:29:00 +02:00
vpc.c	vpc: unlock Coroutine lock to make IO submit Concurrently	2019-04-30 15:29:00 +02:00
vvfat.c	vvfat: Replace bdrv_{read,write}() with bdrv_{pread,pwrite}()	2019-05-10 16:45:40 +02:00
vxhs.c	block: Add strong_runtime_opts to BlockDriver	2019-02-25 15:11:27 +01:00
win32-aio.c	file-win32: Switch to byte-based callbacks	2018-05-15 16:11:41 +02:00
write-threshold.c	qapi: Drop qapi_event_send_FOO()'s Error ** argument	2018-08-28 18:21:38 +02:00