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From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: John Snow <jsnow@redhat.com>,
	"qemu-block@nongnu.org" <qemu-block@nongnu.org>
Cc: "fam@euphon.net" <fam@euphon.net>,
	"kwolf@redhat.com" <kwolf@redhat.com>,
	Denis Lunev <den@virtuozzo.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"armbru@redhat.com" <armbru@redhat.com>,
	"mreitz@redhat.com" <mreitz@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 2/3] block/dirty-bitmap: return int from bdrv_remove_persistent_dirty_bitmap
Date: Mon, 16 Sep 2019 08:22:40 +0000	[thread overview]
Message-ID: <69d06705-311d-de6b-97d2-2cf3545acc12@virtuozzo.com> (raw)
In-Reply-To: <717dad2d-3a78-e64d-6155-a062cd2b0df1@redhat.com>

14.09.2019 1:01, John Snow wrote:
> 
> 
> On 9/11/19 11:00 AM, Vladimir Sementsov-Ogievskiy wrote:
>> It's more comfortable to not deal with local_err.
>>
> 
> I agree.
> 
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   block/qcow2.h                |  5 ++---
>>   include/block/block_int.h    |  6 +++---
>>   include/block/dirty-bitmap.h |  5 ++---
>>   block/dirty-bitmap.c         |  9 +++++----
>>   block/qcow2-bitmap.c         | 20 +++++++++++---------
>>   blockdev.c                   |  7 +++----
>>   6 files changed, 26 insertions(+), 26 deletions(-)
>>
>> diff --git a/block/qcow2.h b/block/qcow2.h
>> index 998bcdaef1..99ee88f802 100644
>> --- a/block/qcow2.h
>> +++ b/block/qcow2.h
>> @@ -747,9 +747,8 @@ bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
>>                                         const char *name,
>>                                         uint32_t granularity,
>>                                         Error **errp);
>> -void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
>> -                                          const char *name,
>> -                                          Error **errp);
>> +int qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
>> +                                         Error **errp);
>>   
>>   ssize_t coroutine_fn
>>   qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
>> diff --git a/include/block/block_int.h b/include/block/block_int.h
>> index 0422acdf1c..503ac9e3cd 100644
>> --- a/include/block/block_int.h
>> +++ b/include/block/block_int.h
>> @@ -556,9 +556,9 @@ struct BlockDriver {
>>                                               const char *name,
>>                                               uint32_t granularity,
>>                                               Error **errp);
>> -    void (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs,
>> -                                                const char *name,
>> -                                                Error **errp);
>> +    int (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs,
>> +                                               const char *name,
>> +                                               Error **errp);
>>   
>>       /**
>>        * Register/unregister a buffer for I/O. For example, when the driver is
>> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
>> index 4b4b731b46..07503b03b5 100644
>> --- a/include/block/dirty-bitmap.h
>> +++ b/include/block/dirty-bitmap.h
>> @@ -37,9 +37,8 @@ int bdrv_dirty_bitmap_check(const BdrvDirtyBitmap *bitmap, uint32_t flags,
>>                               Error **errp);
>>   void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
>>   void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs);
>> -void bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs,
>> -                                         const char *name,
>> -                                         Error **errp);
>> +int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
>> +                                        Error **errp);
>>   void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
>>   void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
>>   void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap);
>> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
>> index 8f42015db9..a52b83b619 100644
>> --- a/block/dirty-bitmap.c
>> +++ b/block/dirty-bitmap.c
>> @@ -455,13 +455,14 @@ void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs)
>>    * not fail.
>>    * This function doesn't release corresponding BdrvDirtyBitmap.
>>    */
>> -void bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs,
>> -                                         const char *name,
>> -                                         Error **errp)
>> +int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
>> +                                        Error **errp)
>>   {
>>       if (bs->drv && bs->drv->bdrv_remove_persistent_dirty_bitmap) {
>> -        bs->drv->bdrv_remove_persistent_dirty_bitmap(bs, name, errp);
>> +        return bs->drv->bdrv_remove_persistent_dirty_bitmap(bs, name, errp);
>>       }
>> +
> 
> But is it a problem if we return an error code without setting errp now?
> If this is for the sake of not having to deal with local_err, we should
> make sure that a non-zero return means that errp is set. Right?

Oops, of course, I should set errp here

> 
>> +    return -ENOTSUP;
>>   }
>>   
>>   bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
>> diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
>> index b2487101ed..1aaedb3b55 100644
>> --- a/block/qcow2-bitmap.c
>> +++ b/block/qcow2-bitmap.c
>> @@ -1404,11 +1404,10 @@ static Qcow2Bitmap *find_bitmap_by_name(Qcow2BitmapList *bm_list,
>>       return NULL;
>>   }
>>   
>> -void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
>> -                                          const char *name,
>> -                                          Error **errp)
>> +int qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
>> +                                         Error **errp)
>>   {
>> -    int ret;
>> +    int ret = 0;
> 
> I was going to say I'd rather not initialize this, but is this related
> to ubsan linting?

Hmm, don't remember. For some reason I thought  it's needed..
Will drop and check what compiler says.

> 
>>       BDRVQcow2State *s = bs->opaque;
>>       Qcow2Bitmap *bm;
>>       Qcow2BitmapList *bm_list;
>> @@ -1416,18 +1415,19 @@ void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
>>       if (s->nb_bitmaps == 0) {
>>           /* Absence of the bitmap is not an error: see explanation above
>>            * bdrv_remove_persistent_dirty_bitmap() definition. */
>> -        return;
>> +        return 0;
>>       }
>>   
>>       bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
>>                                  s->bitmap_directory_size, errp);
>>       if (bm_list == NULL) {
>> -        return;
>> +        return -EIO;
>>       }
>>   
>>       bm = find_bitmap_by_name(bm_list, name);
>>       if (bm == NULL) {
>> -        goto fail;
>> +        ret = -EINVAL;
>> +        goto out;
>>       }
>>   
>>       QSIMPLEQ_REMOVE(bm_list, bm, Qcow2Bitmap, entry);
>> @@ -1435,14 +1435,16 @@ void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
>>       ret = update_ext_header_and_dir(bs, bm_list);
>>       if (ret < 0) {
>>           error_setg_errno(errp, -ret, "Failed to update bitmap extension");
>> -        goto fail;
>> +        goto out;
>>       }
>>   
>>       free_bitmap_clusters(bs, &bm->table);
>>   
>> -fail:
>> +out:
>>       bitmap_free(bm);
>>       bitmap_list_free(bm_list);
>> +
>> +    return ret;
>>   }
>>   
>>   void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp)
>> diff --git a/blockdev.c b/blockdev.c
>> index fbef6845c8..0813adfb2b 100644
>> --- a/blockdev.c
>> +++ b/blockdev.c
>> @@ -2940,15 +2940,14 @@ static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
>>       }
>>   
>>       if (bdrv_dirty_bitmap_get_persistence(bitmap)) {
>> +        int ret;
>>           AioContext *aio_context = bdrv_get_aio_context(bs);
>> -        Error *local_err = NULL;
>>   
>>           aio_context_acquire(aio_context);
>> -        bdrv_remove_persistent_dirty_bitmap(bs, name, &local_err);
>> +        ret = bdrv_remove_persistent_dirty_bitmap(bs, name, errp);
>>           aio_context_release(aio_context);
>>   
>> -        if (local_err != NULL) {
>> -            error_propagate(errp, local_err);
>> +        if (ret < 0) {
>>               return NULL;
>>           }
>>       }
>>


-- 
Best regards,
Vladimir

  reply	other threads:[~2019-09-16  8:24 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-11 15:00 [Qemu-devel] [PATCH v2 0/3] proper locking on bitmap add/remove paths Vladimir Sementsov-Ogievskiy
2019-09-11 15:00 ` [Qemu-devel] [PATCH v2 1/3] block: move bdrv_can_store_new_dirty_bitmap to block/dirty-bitmap.c Vladimir Sementsov-Ogievskiy
2019-09-13 21:51   ` John Snow
2019-09-11 15:00 ` [Qemu-devel] [PATCH v2 2/3] block/dirty-bitmap: return int from bdrv_remove_persistent_dirty_bitmap Vladimir Sementsov-Ogievskiy
2019-09-13 22:01   ` John Snow
2019-09-16  8:22     ` Vladimir Sementsov-Ogievskiy [this message]
2019-09-11 15:00 ` [Qemu-devel] [PATCH v2 3/3] block/qcow2: proper locking on bitmap add/remove paths Vladimir Sementsov-Ogievskiy
2019-09-13 22:26   ` John Snow

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