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Re: [Qemu-devel] [Qemu-block] [PATCH for-2.10 2/5] block: Allow reopen r
From: |
Jeff Cody |
Subject: |
Re: [Qemu-devel] [Qemu-block] [PATCH for-2.10 2/5] block: Allow reopen rw without BDRV_O_ALLOW_RDWR |
Date: |
Thu, 3 Aug 2017 12:22:47 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Thu, Aug 03, 2017 at 05:02:58PM +0200, Kevin Wolf wrote:
> BDRV_O_ALLOW_RDWR is a flag that tells whether qemu can internally
> reopen a node read-write temporarily because the user requested
> read-write for the top-level image, but qemu decided that read-only is
> enough for this node (a backing file).
>
> bdrv_reopen() is different, it is also used for cases where the user
> changed their mind and wants to update the options. There is no reason
> to forbid making a node read-write in that case.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> include/block/block.h | 3 ++-
> block.c | 11 +++++++----
> 2 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/include/block/block.h b/include/block/block.h
> index 34770bb33a..ab80195378 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -436,7 +436,8 @@ int bdrv_is_allocated_above(BlockDriverState *top,
> BlockDriverState *base,
>
> bool bdrv_is_read_only(BlockDriverState *bs);
> bool bdrv_is_writable(BlockDriverState *bs);
> -int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error
> **errp);
> +int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
> + bool ignore_allow_rdw, Error **errp);
> int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
> bool bdrv_is_sg(BlockDriverState *bs);
> bool bdrv_is_inserted(BlockDriverState *bs);
> diff --git a/block.c b/block.c
> index ab908cdc50..2711c3dd3b 100644
> --- a/block.c
> +++ b/block.c
> @@ -246,7 +246,8 @@ bool bdrv_is_writable(BlockDriverState *bs)
> return !bdrv_is_read_only(bs) && !(bs->open_flags & BDRV_O_INACTIVE);
> }
>
> -int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error
> **errp)
> +int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
> + bool ignore_allow_rdw, Error **errp)
I think 'override_allow_rdw' may be a bit clearer, but that is just
bikeshedding.
Reviewed-by: Jeff Cody <address@hidden>
> {
> /* Do not set read_only if copy_on_read is enabled */
> if (bs->copy_on_read && read_only) {
> @@ -256,7 +257,9 @@ int bdrv_can_set_read_only(BlockDriverState *bs, bool
> read_only, Error **errp)
> }
>
> /* Do not clear read_only if it is prohibited */
> - if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR)) {
> + if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) &&
> + !ignore_allow_rdw)
> + {
> error_setg(errp, "Node '%s' is read only",
> bdrv_get_device_or_node_name(bs));
> return -EPERM;
> @@ -269,7 +272,7 @@ int bdrv_set_read_only(BlockDriverState *bs, bool
> read_only, Error **errp)
> {
> int ret = 0;
>
> - ret = bdrv_can_set_read_only(bs, read_only, errp);
> + ret = bdrv_can_set_read_only(bs, read_only, false, errp);
> if (ret < 0) {
> return ret;
> }
> @@ -2907,7 +2910,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
> BlockReopenQueue *queue,
> * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR
> is
> * not set, or if the BDS still has copy_on_read enabled */
> read_only = !(reopen_state->flags & BDRV_O_RDWR);
> - ret = bdrv_can_set_read_only(reopen_state->bs, read_only, &local_err);
> + ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true,
> &local_err);
> if (local_err) {
> error_propagate(errp, local_err);
> goto error;
> --
> 2.13.3
>
>
- Re: [Qemu-devel] [PATCH for-2.10 3/5] block: Set BDRV_O_ALLOW_RDWR during rw reopen, (continued)
- Re: [Qemu-devel] [Qemu-block] [PATCH for-2.10 2/5] block: Allow reopen rw without BDRV_O_ALLOW_RDWR,
Jeff Cody <=
[Qemu-devel] [PATCH for-2.10 1/5] block: Fix order in bdrv_replace_child(), Kevin Wolf, 2017/08/03
[Qemu-devel] [PATCH for-2.10 5/5] qemu-iotests: Test reopen between read-only and read-write, Kevin Wolf, 2017/08/03
Re: [Qemu-devel] [Qemu-block] [PATCH for-2.10 0/5] block: bdrv_reopen() fixes, John Snow, 2017/08/07
Re: [Qemu-devel] [PATCH for-2.10 0/5] block: bdrv_reopen() fixes, Kevin Wolf, 2017/08/08