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Re: [Qemu-devel] [PATCH v20 02/15] block: Introduce op_blockers to Block
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v20 02/15] block: Introduce op_blockers to BlockDriverState |
Date: |
Wed, 21 May 2014 14:28:16 +0200 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, May 20, 2014 at 02:04:27PM +0800, Fam Zheng wrote:
> BlockDriverState.op_blockers is an array of lists with BLOCK_OP_TYPE_MAX
> elements. Each list is a list of blockers of an operation type
> (BlockOpType), that marks this BDS as currently blocked for a certain
> type of operation with reason errors stored in the list. The rule of
> usage is:
>
> * BDS user who wants to take an operation should check if there's any
> blocker of the type with bdrv_op_is_blocked().
>
> * BDS user who wants to block certain types of operation, should call
> bdrv_op_block (or bdrv_op_block_all to block all types of operations,
> which is similar to the existing bdrv_set_in_use()).
>
> * A blocker is only referenced by op_blockers, so the lifecycle is
> managed by caller, and shouldn't be lost until unblock, so typically
> a caller does these:
>
> - Allocate a blocker with error_setg or similar, call bdrv_op_block()
> to block some operations.
> - Hold the blocker, do his job.
> - Unblock operations that it blocked, with the same reason pointer
> passed to bdrv_op_unblock().
> - Release the blocker with error_free().
>
> Signed-off-by: Fam Zheng <address@hidden>
> Reviewed-by: Benoit Canet <address@hidden>
> Reviewed-by: Jeff Cody <address@hidden>
> ---
> block.c | 76
> +++++++++++++++++++++++++++++++++++++++++++++++
> include/block/block.h | 7 +++++
> include/block/block_int.h | 5 ++++
> 3 files changed, 88 insertions(+)
Reviewed-by: Stefan Hajnoczi <address@hidden>
- [Qemu-devel] [PATCH v20 00/15] Drop in_use from BlockDriverState and enable point-in-time snapshot exporting over NBD, Fam Zheng, 2014/05/20
- [Qemu-devel] [PATCH v20 01/15] block: Add BlockOpType enum, Fam Zheng, 2014/05/20
- [Qemu-devel] [PATCH v20 02/15] block: Introduce op_blockers to BlockDriverState, Fam Zheng, 2014/05/20
- Re: [Qemu-devel] [PATCH v20 02/15] block: Introduce op_blockers to BlockDriverState,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH v20 03/15] block: Replace in_use with operation blocker, Fam Zheng, 2014/05/20
- [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Fam Zheng, 2014/05/20
- Re: [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Jeff Cody, 2014/05/20
- Re: [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Fam Zheng, 2014/05/20
- Re: [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Jeff Cody, 2014/05/21
- Re: [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Fam Zheng, 2014/05/21
- Re: [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Stefan Hajnoczi, 2014/05/21
- Re: [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Jeff Cody, 2014/05/21
- Re: [Qemu-devel] [PATCH v20 04/15] block: Move op_blocker check from block_job_create to its caller, Jeff Cody, 2014/05/21