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Re: [Qemu-block] [PATCH for-2.11 4/4] block: Expect graph changes in bdr
From: |
Jeff Cody |
Subject: |
Re: [Qemu-block] [PATCH for-2.11 4/4] block: Expect graph changes in bdrv_parent_drained_begin/end |
Date: |
Tue, 28 Nov 2017 11:10:40 -0500 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Tue, Nov 28, 2017 at 04:43:50PM +0100, Kevin Wolf wrote:
> The .drained_begin/end callbacks can (directly or indirectly via
> aio_poll()) cause block nodes to be removed or the current BdrvChild to
> point to a different child node.
>
> Use QLIST_FOREACH_SAFE() to make sure we don't access invalid
> BlockDriverStates or accidentally continue iterating the parents of the
> new child node instead of the node we actually came from.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> block/io.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/block/io.c b/block/io.c
> index 4fdf93a014..6773926fc1 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -42,9 +42,9 @@ static int coroutine_fn
> bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
>
> void bdrv_parent_drained_begin(BlockDriverState *bs)
> {
> - BdrvChild *c;
> + BdrvChild *c, *next;
>
> - QLIST_FOREACH(c, &bs->parents, next_parent) {
> + QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
> if (c->role->drained_begin) {
> c->role->drained_begin(c);
> }
> @@ -53,9 +53,9 @@ void bdrv_parent_drained_begin(BlockDriverState *bs)
>
> void bdrv_parent_drained_end(BlockDriverState *bs)
> {
> - BdrvChild *c;
> + BdrvChild *c, *next;
>
> - QLIST_FOREACH(c, &bs->parents, next_parent) {
> + QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
> if (c->role->drained_end) {
> c->role->drained_end(c);
> }
> --
> 2.13.6
>
Reviewed-by: Jeff Cody <address@hidden>
- [Qemu-block] [PATCH for-2.11 0/4] Fix qemu-iotests failures, Kevin Wolf, 2017/11/28
- [Qemu-block] [PATCH for-2.11 1/4] Revert "coroutine: abort if we try to schedule or enter a pending coroutine", Kevin Wolf, 2017/11/28
- [Qemu-block] [PATCH for-2.11 3/4] coroutine: Cancel aio_co_schedule() on direct entry, Kevin Wolf, 2017/11/28
- [Qemu-block] [PATCH for-2.11 2/4] Revert "blockjob: do not allow coroutine double entry or entry-after-completion", Kevin Wolf, 2017/11/28
- [Qemu-block] [PATCH for-2.11 4/4] block: Expect graph changes in bdrv_parent_drained_begin/end, Kevin Wolf, 2017/11/28
- Re: [Qemu-block] [PATCH for-2.11 4/4] block: Expect graph changes in bdrv_parent_drained_begin/end,
Jeff Cody <=
- Re: [Qemu-block] [PATCH for-2.11 0/4] Fix qemu-iotests failures, Jeff Cody, 2017/11/28
- Re: [Qemu-block] [PATCH for-2.11 0/4] Fix qemu-iotests failures, Stefan Hajnoczi, 2017/11/28