[PATCH] qcow2: set bdi->is_dirty

Vladimir Sementsov-Ogievskiy posted 1 patch 1 week, 6 days ago
Test checkpatch passed
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20210504160656.462836-1-vsementsov@virtuozzo.com
Maintainers: Max Reitz <mreitz@redhat.com>, Kevin Wolf <kwolf@redhat.com>
block/qcow2.c | 1 +
1 file changed, 1 insertion(+)

[PATCH] qcow2: set bdi->is_dirty

Posted by Vladimir Sementsov-Ogievskiy 1 week, 6 days ago
Set bdi->is_dirty, so that qemu-img info could show dirty flag.

After this commit the following check will show '"dirty-flag": true':

./build/qemu-img create -f qcow2 -o lazy_refcounts=on x 1M
./build/qemu-io x
qemu-io> write 0 1M

 After "write" command success, kill the qemu-io process:

kill -9 <qemu-io pid>

./build/qemu-img info --output=json x

This will show '"dirty-flag": true' among other things. (before this
commit it shows '"dirty-flag": false')

Note, that qcow2's dirty-bit is not a "dirty bit for the image". It
only protects qcow2 lazy refcounts feature. So, there are a lot of
conditions when qcow2 session may be not closed correctly, but bit is
0. Still, when bit is set, the last session is definitely not finished
correctly and it's better to report it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/qcow2.c b/block/qcow2.c
index 9727ae8fe3..39b91ef940 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5089,6 +5089,7 @@ static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     BDRVQcow2State *s = bs->opaque;
     bdi->cluster_size = s->cluster_size;
     bdi->vm_state_offset = qcow2_vm_state_offset(s);
+    bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY;
     return 0;
 }
 
-- 
2.29.2


Re: [PATCH] qcow2: set bdi->is_dirty

Posted by Kevin Wolf 1 week, 6 days ago
Am 04.05.2021 um 18:06 hat Vladimir Sementsov-Ogievskiy geschrieben:
> Set bdi->is_dirty, so that qemu-img info could show dirty flag.
> 
> After this commit the following check will show '"dirty-flag": true':
> 
> ./build/qemu-img create -f qcow2 -o lazy_refcounts=on x 1M
> ./build/qemu-io x
> qemu-io> write 0 1M
> 
>  After "write" command success, kill the qemu-io process:
> 
> kill -9 <qemu-io pid>
> 
> ./build/qemu-img info --output=json x
> 
> This will show '"dirty-flag": true' among other things. (before this
> commit it shows '"dirty-flag": false')
> 
> Note, that qcow2's dirty-bit is not a "dirty bit for the image". It
> only protects qcow2 lazy refcounts feature. So, there are a lot of
> conditions when qcow2 session may be not closed correctly, but bit is
> 0. Still, when bit is set, the last session is definitely not finished
> correctly and it's better to report it.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Thanks, applied to the block branch.

Kevin


Re: [PATCH] qcow2: set bdi->is_dirty

Posted by Kirill Tkhai 1 week, 6 days ago
On 04.05.2021 19:06, Vladimir Sementsov-Ogievskiy wrote:
> Set bdi->is_dirty, so that qemu-img info could show dirty flag.
> 
> After this commit the following check will show '"dirty-flag": true':
> 
> ./build/qemu-img create -f qcow2 -o lazy_refcounts=on x 1M
> ./build/qemu-io x
> qemu-io> write 0 1M
> 
>  After "write" command success, kill the qemu-io process:
> 
> kill -9 <qemu-io pid>
> 
> ./build/qemu-img info --output=json x
> 
> This will show '"dirty-flag": true' among other things. (before this
> commit it shows '"dirty-flag": false')
> 
> Note, that qcow2's dirty-bit is not a "dirty bit for the image". It
> only protects qcow2 lazy refcounts feature. So, there are a lot of
> conditions when qcow2 session may be not closed correctly, but bit is
> 0. Still, when bit is set, the last session is definitely not finished
> correctly and it's better to report it.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Works for me. Thanks,

Tested-by: Kirill Tkhai <ktkhai@virtuozzo.com>

> ---
>  block/qcow2.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 9727ae8fe3..39b91ef940 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -5089,6 +5089,7 @@ static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
>      BDRVQcow2State *s = bs->opaque;
>      bdi->cluster_size = s->cluster_size;
>      bdi->vm_state_offset = qcow2_vm_state_offset(s);
> +    bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY;
>      return 0;
>  }
>  
> 


Re: [PATCH] qcow2: set bdi->is_dirty

Posted by Eric Blake 1 week, 6 days ago
On 5/4/21 11:06 AM, Vladimir Sementsov-Ogievskiy wrote:
> Set bdi->is_dirty, so that qemu-img info could show dirty flag.
> 
> After this commit the following check will show '"dirty-flag": true':
> 
> ./build/qemu-img create -f qcow2 -o lazy_refcounts=on x 1M
> ./build/qemu-io x
> qemu-io> write 0 1M
> 
>  After "write" command success, kill the qemu-io process:
> 
> kill -9 <qemu-io pid>
> 
> ./build/qemu-img info --output=json x
> 
> This will show '"dirty-flag": true' among other things. (before this
> commit it shows '"dirty-flag": false')
> 
> Note, that qcow2's dirty-bit is not a "dirty bit for the image". It
> only protects qcow2 lazy refcounts feature. So, there are a lot of
> conditions when qcow2 session may be not closed correctly, but bit is
> 0. Still, when bit is set, the last session is definitely not finished
> correctly and it's better to report it.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/qcow2.c | 1 +
>  1 file changed, 1 insertion(+)

Reviewed-by: Eric Blake <eblake@redhat.com>


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org