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Re: [PATCH v2 5/7] block: Fix cross-AioContext blockdev-snapshot
From: |
Peter Krempa |
Subject: |
Re: [PATCH v2 5/7] block: Fix cross-AioContext blockdev-snapshot |
Date: |
Tue, 10 Mar 2020 14:27:13 +0100 |
User-agent: |
Mutt/1.13.3 (2020-01-12) |
On Tue, Mar 10, 2020 at 12:38:29 +0100, Kevin Wolf wrote:
> external_snapshot_prepare() tries to move the overlay to the AioContext
> of the backing file (the snapshotted node). However, it's possible that
> this doesn't work, but the backing file can instead be moved to the
> overlay's AioContext (e.g. opening the backing chain for a mirror
> target).
>
> bdrv_append() already indirectly uses bdrv_attach_node(), which takes
> care to move nodes to make sure they use the same AioContext and which
> tries both directions.
>
> So the problem has a simple fix: Just delete the unnecessary extra
> bdrv_try_set_aio_context() call in external_snapshot_prepare() and
> instead assert in bdrv_append() that both nodes were indeed moved to the
> same AioContext.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> block.c | 1 +
> blockdev.c | 16 ----------------
> 2 files changed, 1 insertion(+), 16 deletions(-)
Tested-by: Peter Krempa <address@hidden>
Unfortunately I don't feel confident enough in the intricacies of the
aio contexts. Nevertheless Fixing bugs by deleting code is awesome!
- [PATCH v2 0/7] block: Relax restrictions for blockdev-snapshot, Kevin Wolf, 2020/03/10
- [PATCH v2 1/7] block: Make bdrv_get_cumulative_perm() public, Kevin Wolf, 2020/03/10
- [PATCH v2 2/7] block: Relax restrictions for blockdev-snapshot, Kevin Wolf, 2020/03/10
- [PATCH v2 3/7] iotests: Fix run_job() with use_log=False, Kevin Wolf, 2020/03/10
- [PATCH v2 5/7] block: Fix cross-AioContext blockdev-snapshot, Kevin Wolf, 2020/03/10
- Re: [PATCH v2 5/7] block: Fix cross-AioContext blockdev-snapshot,
Peter Krempa <=
- [PATCH v2 4/7] iotests: Test mirror with temporarily disabled target backing file, Kevin Wolf, 2020/03/10
- [PATCH v2 6/7] iotests: Add iothread cases to 155, Kevin Wolf, 2020/03/10
- [PATCH v2 7/7] qapi: Add '@allow-write-only-overlay' feature for 'blockdev-snapshot', Kevin Wolf, 2020/03/10
- Re: [PATCH v2 0/7] block: Relax restrictions for blockdev-snapshot, Kevin Wolf, 2020/03/10