From: Hanna Reitz <hreitz@redhat.com>
To: Emanuele Giuseppe Esposito <eesposit@redhat.com>, qemu-block@nongnu.org
Cc: "Kevin Wolf" <kwolf@redhat.com>, "Fam Zheng" <fam@euphon.net>,
"Vladimir Sementsov-Ogievskiy" <vsementsov@virtuozzo.com>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Juan Quintela" <quintela@redhat.com>,
qemu-devel@nongnu.org, "John Snow" <jsnow@redhat.com>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Markus Armbruster" <armbru@redhat.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Eric Blake" <eblake@redhat.com>
Subject: Re: [PATCH v5 09/31] block: introduce assert_bdrv_graph_writable
Date: Fri, 10 Dec 2021 18:43:39 +0100 [thread overview]
Message-ID: <6dd02c7c-5f0e-9dce-28b8-6ed7fb834a50@redhat.com> (raw)
In-Reply-To: <20211124064418.3120601-10-eesposit@redhat.com>
On 24.11.21 07:43, Emanuele Giuseppe Esposito wrote:
> We want to be sure that the functions that write the child and
> parent list of a bs are under BQL and drain.
>
> BQL prevents from concurrent writings from the GS API, while
> drains protect from I/O.
>
> TODO: drains are missing in some functions using this assert.
> Therefore a proper assertion will fail. Because adding drains
> requires additional discussions, they will be added in future
> series.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
> include/block/block_int-global-state.h | 10 +++++++++-
> block.c | 4 ++++
> block/io.c | 11 +++++++++++
> 3 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h
> index a1b7d0579d..fa96e8b449 100644
> --- a/include/block/block_int-global-state.h
> +++ b/include/block/block_int-global-state.h
> @@ -312,4 +312,12 @@ void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
> */
> void bdrv_drain_all_end_quiesce(BlockDriverState *bs);
>
> -#endif /* BLOCK_INT_GLOBAL_STATE*/
This looks like it should be squashed into patch 7, sorry I missed this
in v4...
(Rest of this patch looks good to me, for the record – and while I’m at
it, for patches I didn’t reply to so far, I planned to send an R-b
later. But then there’s things like patches 2/3 looking good to me, but
it turned out in my review for patch 4 that bdrv_lock_medium() is used
in an I/O path, so I can’t really send an R-b now anymore...)
Hanna
> +/**
> + * Make sure that the function is running under both drain and BQL.
> + * The latter protects from concurrent writings
> + * from the GS API, while the former prevents concurrent reads
> + * from I/O.
> + */
> +void assert_bdrv_graph_writable(BlockDriverState *bs);
> +
> +#endif /* BLOCK_INT_GLOBAL_STATE */
> diff --git a/block.c b/block.c
> index 198ec636ff..522a273140 100644
> --- a/block.c
> +++ b/block.c
> @@ -1416,6 +1416,7 @@ static void bdrv_child_cb_attach(BdrvChild *child)
> {
> BlockDriverState *bs = child->opaque;
>
> + assert_bdrv_graph_writable(bs);
> QLIST_INSERT_HEAD(&bs->children, child, next);
>
> if (child->role & BDRV_CHILD_COW) {
> @@ -1435,6 +1436,7 @@ static void bdrv_child_cb_detach(BdrvChild *child)
>
> bdrv_unapply_subtree_drain(child, bs);
>
> + assert_bdrv_graph_writable(bs);
> QLIST_REMOVE(child, next);
> }
>
> @@ -2818,6 +2820,7 @@ static void bdrv_replace_child_noperm(BdrvChild **childp,
> if (child->klass->detach) {
> child->klass->detach(child);
> }
> + assert_bdrv_graph_writable(old_bs);
> QLIST_REMOVE(child, next_parent);
> }
>
> @@ -2827,6 +2830,7 @@ static void bdrv_replace_child_noperm(BdrvChild **childp,
> }
>
> if (new_bs) {
> + assert_bdrv_graph_writable(new_bs);
> QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
>
> /*
> diff --git a/block/io.c b/block/io.c
> index cb095deeec..3be08cad29 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -734,6 +734,17 @@ void bdrv_drain_all(void)
> bdrv_drain_all_end();
> }
>
> +void assert_bdrv_graph_writable(BlockDriverState *bs)
> +{
> + /*
> + * TODO: this function is incomplete. Because the users of this
> + * assert lack the necessary drains, check only for BQL.
> + * Once the necessary drains are added,
> + * assert also for qatomic_read(&bs->quiesce_counter) > 0
> + */
> + assert(qemu_in_main_thread());
> +}
> +
> /**
> * Remove an active request from the tracked requests list
> *
next prev parent reply other threads:[~2021-12-10 17:44 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 6:43 [PATCH v5 00/31] block layer: split block APIs in global state and I/O Emanuele Giuseppe Esposito
2021-11-24 6:43 ` [PATCH v5 01/31] main-loop.h: introduce qemu_in_main_thread() Emanuele Giuseppe Esposito
2021-11-24 6:43 ` [PATCH v5 02/31] include/block/block: split header into I/O and global state API Emanuele Giuseppe Esposito
2021-11-24 6:43 ` [PATCH v5 03/31] assertions for block " Emanuele Giuseppe Esposito
2021-12-16 15:17 ` Hanna Reitz
2021-11-24 6:43 ` [PATCH v5 04/31] include/sysemu/block-backend: split header into I/O and global state (GS) API Emanuele Giuseppe Esposito
2021-12-10 14:21 ` Hanna Reitz
2021-11-24 6:43 ` [PATCH v5 05/31] block-backend: special comments for blk_set/get_perm due to fuse Emanuele Giuseppe Esposito
2021-12-10 14:38 ` Hanna Reitz
2021-12-15 8:57 ` Emanuele Giuseppe Esposito
2021-12-15 10:13 ` Emanuele Giuseppe Esposito
2021-12-16 14:00 ` Hanna Reitz
2021-11-24 6:43 ` [PATCH v5 06/31] block/block-backend.c: assertions for block-backend Emanuele Giuseppe Esposito
2021-12-10 15:37 ` Hanna Reitz
2021-11-24 6:43 ` [PATCH v5 07/31] include/block/block_int: split header into I/O and global state API Emanuele Giuseppe Esposito
2021-11-24 6:43 ` [PATCH v5 08/31] assertions for block_int " Emanuele Giuseppe Esposito
2021-11-24 6:43 ` [PATCH v5 09/31] block: introduce assert_bdrv_graph_writable Emanuele Giuseppe Esposito
2021-12-10 17:43 ` Hanna Reitz [this message]
2021-12-14 19:48 ` Emanuele Giuseppe Esposito
2021-12-16 14:01 ` Hanna Reitz
2021-11-24 6:43 ` [PATCH v5 10/31] block.c: modify .attach and .detach callbacks of child_of_bds Emanuele Giuseppe Esposito
2021-12-16 14:57 ` Hanna Reitz
2021-12-16 16:05 ` Emanuele Giuseppe Esposito
2021-12-16 16:12 ` Hanna Reitz
2021-11-24 6:43 ` [PATCH v5 11/31] include/block/blockjob_int.h: split header into I/O and GS API Emanuele Giuseppe Esposito
2021-11-24 6:43 ` [PATCH v5 12/31] assertions for blockjob_int.h Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 13/31] block.c: add assertions to static functions Emanuele Giuseppe Esposito
2021-12-16 16:08 ` Hanna Reitz
2021-12-16 16:39 ` Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 14/31] include/block/blockjob.h: global state API Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 15/31] assertions for blockjob.h " Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 16/31] include/sysemu/blockdev.h: " Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 17/31] assertions for blockdev.h " Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 18/31] include/block/snapshot: global state API + assertions Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 19/31] block/copy-before-write.h: " Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 20/31] block/coroutines: I/O API Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 21/31] block_int-common.h: split function pointers in BlockDriver Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 22/31] block_int-common.h: assertion in the callers of BlockDriver function pointers Emanuele Giuseppe Esposito
2021-12-16 18:43 ` Hanna Reitz
2021-12-17 15:53 ` Emanuele Giuseppe Esposito
2021-12-17 16:00 ` Hanna Reitz
2021-11-24 6:44 ` [PATCH v5 23/31] block_int-common.h: split function pointers in BdrvChildClass Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 24/31] block_int-common.h: assertions in the callers of BdrvChildClass function pointers Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 25/31] block-backend-common.h: split function pointers in BlockDevOps Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 26/31] job.h: split function pointers in JobDriver Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 27/31] job.h: assertions in the callers of JobDriver funcion pointers Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 28/31] block.c: assert BQL lock held in bdrv_co_invalidate_cache Emanuele Giuseppe Esposito
2021-12-17 11:04 ` Hanna Reitz
2021-12-17 16:38 ` Emanuele Giuseppe Esposito
2021-12-20 12:20 ` Emanuele Giuseppe Esposito
2021-12-23 17:11 ` Hanna Reitz
2022-01-19 15:57 ` Hanna Reitz
2022-01-19 17:44 ` Hanna Reitz
2022-01-19 18:34 ` Kevin Wolf
2022-01-20 13:22 ` Paolo Bonzini
2022-01-20 13:48 ` Kevin Wolf
2022-01-21 10:22 ` Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 29/31] jobs: introduce pre_run function in JobDriver Emanuele Giuseppe Esposito
2021-11-24 6:44 ` [PATCH v5 30/31] crypto: delegate permission functions to JobDriver .pre_run Emanuele Giuseppe Esposito
2021-12-17 12:29 ` Hanna Reitz
2021-12-17 14:32 ` Hanna Reitz
2021-12-20 15:47 ` Emanuele Giuseppe Esposito
2021-12-23 17:15 ` Hanna Reitz
2021-11-24 6:44 ` [PATCH v5 31/31] block.c: assertions to the block layer permissions API Emanuele Giuseppe Esposito
2021-11-29 13:32 ` [PATCH v5 00/31] block layer: split block APIs in global state and I/O Stefan Hajnoczi
2021-11-30 8:39 ` Emanuele Giuseppe Esposito
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