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[v5,01/10] block: Hide HBitmap in block dirty bitmap interface

Message ID 1464928382-9650-2-git-send-email-famz@redhat.com
State New
Headers show

Commit Message

Fam Zheng June 3, 2016, 4:32 a.m. UTC
HBitmap is an implementation detail of block dirty bitmap that should be hidden
from users. Introduce a BdrvDirtyBitmapIter to encapsulate the underlying
HBitmapIter.

A small difference in the interface is, before, an HBitmapIter is initialized
in place, now the new BdrvDirtyBitmapIter must be dynamically allocated because
the structure definition is in block/dirty-bitmap.c.

Two current users are converted too.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/backup.c               | 14 ++++++++------
 block/dirty-bitmap.c         | 39 +++++++++++++++++++++++++++++++++------
 block/mirror.c               | 24 +++++++++++++-----------
 include/block/dirty-bitmap.h |  7 +++++--
 include/qemu/typedefs.h      |  1 +
 5 files changed, 60 insertions(+), 25 deletions(-)

Comments

Max Reitz June 22, 2016, 3:10 p.m. UTC | #1
On 03.06.2016 06:32, Fam Zheng wrote:
> HBitmap is an implementation detail of block dirty bitmap that should be hidden
> from users. Introduce a BdrvDirtyBitmapIter to encapsulate the underlying
> HBitmapIter.
> 
> A small difference in the interface is, before, an HBitmapIter is initialized
> in place, now the new BdrvDirtyBitmapIter must be dynamically allocated because
> the structure definition is in block/dirty-bitmap.c.
> 
> Two current users are converted too.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/backup.c               | 14 ++++++++------
>  block/dirty-bitmap.c         | 39 +++++++++++++++++++++++++++++++++------
>  block/mirror.c               | 24 +++++++++++++-----------
>  include/block/dirty-bitmap.h |  7 +++++--
>  include/qemu/typedefs.h      |  1 +
>  5 files changed, 60 insertions(+), 25 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>
Vladimir Sementsov-Ogievskiy June 28, 2016, 3:36 p.m. UTC | #2
On 03.06.2016 07:32, Fam Zheng wrote:
> HBitmap is an implementation detail of block dirty bitmap that should be hidden
> from users. Introduce a BdrvDirtyBitmapIter to encapsulate the underlying
> HBitmapIter.
>
> A small difference in the interface is, before, an HBitmapIter is initialized
> in place, now the new BdrvDirtyBitmapIter must be dynamically allocated because
> the structure definition is in block/dirty-bitmap.c.
>
> Two current users are converted too.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>   block/backup.c               | 14 ++++++++------
>   block/dirty-bitmap.c         | 39 +++++++++++++++++++++++++++++++++------
>   block/mirror.c               | 24 +++++++++++++-----------
>   include/block/dirty-bitmap.h |  7 +++++--
>   include/qemu/typedefs.h      |  1 +
>   5 files changed, 60 insertions(+), 25 deletions(-)
>
> diff --git a/block/backup.c b/block/backup.c
> index feeb9f8..ac7ca45 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -317,14 +317,14 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>       int64_t end;
>       int64_t last_cluster = -1;
>       int64_t sectors_per_cluster = cluster_size_sectors(job);
> -    HBitmapIter hbi;
> +    BdrvDirtyBitmapIter *dbi;
>   
>       granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap);
>       clusters_per_iter = MAX((granularity / job->cluster_size), 1);
> -    bdrv_dirty_iter_init(job->sync_bitmap, &hbi);
> +    dbi = bdrv_dirty_iter_new(job->sync_bitmap, 0);
>   
>       /* Find the next dirty sector(s) */
> -    while ((sector = hbitmap_iter_next(&hbi)) != -1) {
> +    while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
>           cluster = sector / sectors_per_cluster;
>   
>           /* Fake progress updates for any clusters we skipped */
> @@ -336,7 +336,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>           for (end = cluster + clusters_per_iter; cluster < end; cluster++) {
>               do {
>                   if (yield_and_check(job)) {
> -                    return ret;
> +                    goto out;
>                   }
>                   ret = backup_do_cow(job, cluster * sectors_per_cluster,
>                                       sectors_per_cluster, &error_is_read,
> @@ -344,7 +344,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>                   if ((ret < 0) &&
>                       backup_error_action(job, error_is_read, -ret) ==
>                       BLOCK_ERROR_ACTION_REPORT) {
> -                    return ret;
> +                    goto out;
>                   }
>               } while (ret < 0);
>           }
> @@ -352,7 +352,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>           /* If the bitmap granularity is smaller than the backup granularity,
>            * we need to advance the iterator pointer to the next cluster. */
>           if (granularity < job->cluster_size) {
> -            bdrv_set_dirty_iter(&hbi, cluster * sectors_per_cluster);
> +            bdrv_set_dirty_iter(dbi, cluster * sectors_per_cluster);
>           }
>   
>           last_cluster = cluster - 1;
> @@ -364,6 +364,8 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>           job->common.offset += ((end - last_cluster - 1) * job->cluster_size);
>       }
>   
> +out:
> +    bdrv_dirty_iter_free(dbi);
>       return ret;
>   }
>   
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 4902ca5..ec073ee 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -42,9 +42,15 @@ struct BdrvDirtyBitmap {
>       char *name;                 /* Optional non-empty unique ID */
>       int64_t size;               /* Size of the bitmap (Number of sectors) */
>       bool disabled;              /* Bitmap is read-only */
> +    int active_iterators;       /* How many iterators are active */
>       QLIST_ENTRY(BdrvDirtyBitmap) list;
>   };
>   
> +struct BdrvDirtyBitmapIter {
> +    HBitmapIter hbi;
> +    BdrvDirtyBitmap *bitmap;
> +};
> +
>   BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
>   {
>       BdrvDirtyBitmap *bm;
> @@ -212,6 +218,7 @@ void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
>   
>       QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
>           assert(!bdrv_dirty_bitmap_frozen(bitmap));
> +        assert(!bitmap->active_iterators);
>           hbitmap_truncate(bitmap->bitmap, size);
>           bitmap->size = size;
>       }
> @@ -224,6 +231,7 @@ static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
>       BdrvDirtyBitmap *bm, *next;
>       QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
>           if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
> +            assert(!bitmap->active_iterators);
>               assert(!bdrv_dirty_bitmap_frozen(bm));
>               QLIST_REMOVE(bm, list);
>               hbitmap_free(bm->bitmap);
> @@ -320,9 +328,29 @@ uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
>       return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
>   }
>   
> -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
> +                                         uint64_t first_sector)

can you use const BdrvDirtyBitmap * pointer ? To allow iterating through 
const bitmap, in store_to_file function foe ex.

>   {
> -    hbitmap_iter_init(hbi, bitmap->bitmap, 0);
> +    BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
> +    hbitmap_iter_init(&iter->hbi, bitmap->bitmap, first_sector);
> +    iter->bitmap = bitmap;
> +    bitmap->active_iterators++;
> +    return iter;
> +}
> +
> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
> +{
> +    if (!iter) {
> +        return;
> +    }
> +    assert(iter->bitmap->active_iterators > 0);
> +    iter->bitmap->active_iterators--;
> +    g_free(iter);
> +}
> +
> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
> +{
> +    return hbitmap_iter_next(&iter->hbi);
>   }
>   
>   void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> @@ -373,12 +401,11 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
>   }
>   
>   /**
> - * Advance an HBitmapIter to an arbitrary offset.
> + * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
>    */
> -void bdrv_set_dirty_iter(HBitmapIter *hbi, int64_t offset)
> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t sector_num)
>   {
> -    assert(hbi->hb);
> -    hbitmap_iter_init(hbi, hbi->hb, offset);
> +    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, sector_num);
>   }
>   
>   int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
> diff --git a/block/mirror.c b/block/mirror.c
> index 80fd3c7..1d90aa5 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -52,7 +52,7 @@ typedef struct MirrorBlockJob {
>       int64_t bdev_length;
>       unsigned long *cow_bitmap;
>       BdrvDirtyBitmap *dirty_bitmap;
> -    HBitmapIter hbi;
> +    BdrvDirtyBitmapIter *dbi;
>       uint8_t *buf;
>       QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
>       int buf_free_count;
> @@ -317,10 +317,10 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>       int64_t end = s->bdev_length / BDRV_SECTOR_SIZE;
>       int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
>   
> -    sector_num = hbitmap_iter_next(&s->hbi);
> +    sector_num = bdrv_dirty_iter_next(s->dbi);
>       if (sector_num < 0) {
> -        bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
> -        sector_num = hbitmap_iter_next(&s->hbi);
> +        bdrv_set_dirty_iter(s->dbi, 0);
> +        sector_num = bdrv_dirty_iter_next(s->dbi);
>           trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
>           assert(sector_num >= 0);
>       }
> @@ -334,7 +334,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>       /* Find the number of consective dirty chunks following the first dirty
>        * one, and wait for in flight requests in them. */
>       while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) {
> -        int64_t hbitmap_next;
> +        int64_t next_dirty;
>           int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk;
>           int64_t next_chunk = next_sector / sectors_per_chunk;
>           if (next_sector >= end ||
> @@ -345,13 +345,13 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>               break;
>           }
>   
> -        hbitmap_next = hbitmap_iter_next(&s->hbi);
> -        if (hbitmap_next > next_sector || hbitmap_next < 0) {
> +        next_dirty = bdrv_dirty_iter_next(s->dbi);
> +        if (next_dirty > next_sector || next_dirty < 0) {
>               /* The bitmap iterator's cache is stale, refresh it */
> -            bdrv_set_dirty_iter(&s->hbi, next_sector);
> -            hbitmap_next = hbitmap_iter_next(&s->hbi);
> +            bdrv_set_dirty_iter(s->dbi, next_sector);
> +            next_dirty = bdrv_dirty_iter_next(s->dbi);
>           }
> -        assert(hbitmap_next == next_sector);
> +        assert(next_dirty == next_sector);
>           nb_chunks++;
>       }
>   
> @@ -601,7 +601,8 @@ static void coroutine_fn mirror_run(void *opaque)
>           }
>       }
>   
> -    bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
> +    assert(!s->dbi);
> +    s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0);
>       for (;;) {
>           uint64_t delay_ns = 0;
>           int64_t cnt;
> @@ -712,6 +713,7 @@ immediate_exit:
>       qemu_vfree(s->buf);
>       g_free(s->cow_bitmap);
>       g_free(s->in_flight_bitmap);
> +    bdrv_dirty_iter_free(s->dbi);
>       bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
>   
>       data = g_malloc(sizeof(*data));
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index 80afe60..2ea601b 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -36,8 +36,11 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>                              int64_t cur_sector, int nr_sectors);
>   void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>                                int64_t cur_sector, int nr_sectors);
> -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
> -void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
> +                                         uint64_t first_sector);
> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
>   int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
>   void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
>   
> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
> index b113fcf..1b8c30a 100644
> --- a/include/qemu/typedefs.h
> +++ b/include/qemu/typedefs.h
> @@ -11,6 +11,7 @@ typedef struct AioContext AioContext;
>   typedef struct AllwinnerAHCIState AllwinnerAHCIState;
>   typedef struct AudioState AudioState;
>   typedef struct BdrvDirtyBitmap BdrvDirtyBitmap;
> +typedef struct BdrvDirtyBitmapIter BdrvDirtyBitmapIter;
>   typedef struct BlockBackend BlockBackend;
>   typedef struct BlockBackendRootState BlockBackendRootState;
>   typedef struct BlockDriverState BlockDriverState;
Vladimir Sementsov-Ogievskiy June 28, 2016, 3:39 p.m. UTC | #3
On 28.06.2016 18:36, Vladimir Sementsov-Ogievskiy wrote:
> On 03.06.2016 07:32, Fam Zheng wrote:
>> HBitmap is an implementation detail of block dirty bitmap that should 
>> be hidden
>> from users. Introduce a BdrvDirtyBitmapIter to encapsulate the 
>> underlying
>> HBitmapIter.
>>
>> A small difference in the interface is, before, an HBitmapIter is 
>> initialized
>> in place, now the new BdrvDirtyBitmapIter must be dynamically 
>> allocated because
>> the structure definition is in block/dirty-bitmap.c.
>>
>> Two current users are converted too.
>>
>> Signed-off-by: Fam Zheng <famz@redhat.com>
>> ---
>>   block/backup.c               | 14 ++++++++------
>>   block/dirty-bitmap.c         | 39 
>> +++++++++++++++++++++++++++++++++------
>>   block/mirror.c               | 24 +++++++++++++-----------
>>   include/block/dirty-bitmap.h |  7 +++++--
>>   include/qemu/typedefs.h      |  1 +
>>   5 files changed, 60 insertions(+), 25 deletions(-)
>>
>> diff --git a/block/backup.c b/block/backup.c
>> index feeb9f8..ac7ca45 100644
>> --- a/block/backup.c
>> +++ b/block/backup.c
>> @@ -317,14 +317,14 @@ static int coroutine_fn 
>> backup_run_incremental(BackupBlockJob *job)
>>       int64_t end;
>>       int64_t last_cluster = -1;
>>       int64_t sectors_per_cluster = cluster_size_sectors(job);
>> -    HBitmapIter hbi;
>> +    BdrvDirtyBitmapIter *dbi;
>>         granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap);
>>       clusters_per_iter = MAX((granularity / job->cluster_size), 1);
>> -    bdrv_dirty_iter_init(job->sync_bitmap, &hbi);
>> +    dbi = bdrv_dirty_iter_new(job->sync_bitmap, 0);
>>         /* Find the next dirty sector(s) */
>> -    while ((sector = hbitmap_iter_next(&hbi)) != -1) {
>> +    while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
>>           cluster = sector / sectors_per_cluster;
>>             /* Fake progress updates for any clusters we skipped */
>> @@ -336,7 +336,7 @@ static int coroutine_fn 
>> backup_run_incremental(BackupBlockJob *job)
>>           for (end = cluster + clusters_per_iter; cluster < end; 
>> cluster++) {
>>               do {
>>                   if (yield_and_check(job)) {
>> -                    return ret;
>> +                    goto out;
>>                   }
>>                   ret = backup_do_cow(job, cluster * 
>> sectors_per_cluster,
>>                                       sectors_per_cluster, 
>> &error_is_read,
>> @@ -344,7 +344,7 @@ static int coroutine_fn 
>> backup_run_incremental(BackupBlockJob *job)
>>                   if ((ret < 0) &&
>>                       backup_error_action(job, error_is_read, -ret) ==
>>                       BLOCK_ERROR_ACTION_REPORT) {
>> -                    return ret;
>> +                    goto out;
>>                   }
>>               } while (ret < 0);
>>           }
>> @@ -352,7 +352,7 @@ static int coroutine_fn 
>> backup_run_incremental(BackupBlockJob *job)
>>           /* If the bitmap granularity is smaller than the backup 
>> granularity,
>>            * we need to advance the iterator pointer to the next 
>> cluster. */
>>           if (granularity < job->cluster_size) {
>> -            bdrv_set_dirty_iter(&hbi, cluster * sectors_per_cluster);
>> +            bdrv_set_dirty_iter(dbi, cluster * sectors_per_cluster);
>>           }
>>             last_cluster = cluster - 1;
>> @@ -364,6 +364,8 @@ static int coroutine_fn 
>> backup_run_incremental(BackupBlockJob *job)
>>           job->common.offset += ((end - last_cluster - 1) * 
>> job->cluster_size);
>>       }
>>   +out:
>> +    bdrv_dirty_iter_free(dbi);
>>       return ret;
>>   }
>>   diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
>> index 4902ca5..ec073ee 100644
>> --- a/block/dirty-bitmap.c
>> +++ b/block/dirty-bitmap.c
>> @@ -42,9 +42,15 @@ struct BdrvDirtyBitmap {
>>       char *name;                 /* Optional non-empty unique ID */
>>       int64_t size;               /* Size of the bitmap (Number of 
>> sectors) */
>>       bool disabled;              /* Bitmap is read-only */
>> +    int active_iterators;       /* How many iterators are active */
>>       QLIST_ENTRY(BdrvDirtyBitmap) list;
>>   };
>>   +struct BdrvDirtyBitmapIter {
>> +    HBitmapIter hbi;
>> +    BdrvDirtyBitmap *bitmap;
>> +};
>> +
>>   BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const 
>> char *name)
>>   {
>>       BdrvDirtyBitmap *bm;
>> @@ -212,6 +218,7 @@ void bdrv_dirty_bitmap_truncate(BlockDriverState 
>> *bs)
>>         QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
>>           assert(!bdrv_dirty_bitmap_frozen(bitmap));
>> +        assert(!bitmap->active_iterators);
>>           hbitmap_truncate(bitmap->bitmap, size);
>>           bitmap->size = size;
>>       }
>> @@ -224,6 +231,7 @@ static void 
>> bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
>>       BdrvDirtyBitmap *bm, *next;
>>       QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
>>           if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
>> +            assert(!bitmap->active_iterators);
>>               assert(!bdrv_dirty_bitmap_frozen(bm));
>>               QLIST_REMOVE(bm, list);
>>               hbitmap_free(bm->bitmap);
>> @@ -320,9 +328,29 @@ uint32_t 
>> bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
>>       return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
>>   }
>>   -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
>> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
>> +                                         uint64_t first_sector)
>
> can you use const BdrvDirtyBitmap * pointer ? To allow iterating 
> through const bitmap, in store_to_file function foe ex.

I see, no, because of 'bitmap->active_iterators++'...

>
>>   {
>> -    hbitmap_iter_init(hbi, bitmap->bitmap, 0);
>> +    BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
>> +    hbitmap_iter_init(&iter->hbi, bitmap->bitmap, first_sector);
>> +    iter->bitmap = bitmap;
>> +    bitmap->active_iterators++;
>> +    return iter;
>> +}
>> +
>> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
>> +{
>> +    if (!iter) {
>> +        return;
>> +    }
>> +    assert(iter->bitmap->active_iterators > 0);
>> +    iter->bitmap->active_iterators--;
>> +    g_free(iter);
>> +}
>> +
>> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
>> +{
>> +    return hbitmap_iter_next(&iter->hbi);
>>   }
>>     void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>> @@ -373,12 +401,11 @@ void bdrv_set_dirty(BlockDriverState *bs, 
>> int64_t cur_sector,
>>   }
>>     /**
>> - * Advance an HBitmapIter to an arbitrary offset.
>> + * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
>>    */
>> -void bdrv_set_dirty_iter(HBitmapIter *hbi, int64_t offset)
>> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t sector_num)
>>   {
>> -    assert(hbi->hb);
>> -    hbitmap_iter_init(hbi, hbi->hb, offset);
>> +    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, sector_num);
>>   }
>>     int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
>> diff --git a/block/mirror.c b/block/mirror.c
>> index 80fd3c7..1d90aa5 100644
>> --- a/block/mirror.c
>> +++ b/block/mirror.c
>> @@ -52,7 +52,7 @@ typedef struct MirrorBlockJob {
>>       int64_t bdev_length;
>>       unsigned long *cow_bitmap;
>>       BdrvDirtyBitmap *dirty_bitmap;
>> -    HBitmapIter hbi;
>> +    BdrvDirtyBitmapIter *dbi;
>>       uint8_t *buf;
>>       QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
>>       int buf_free_count;
>> @@ -317,10 +317,10 @@ static uint64_t coroutine_fn 
>> mirror_iteration(MirrorBlockJob *s)
>>       int64_t end = s->bdev_length / BDRV_SECTOR_SIZE;
>>       int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
>>   -    sector_num = hbitmap_iter_next(&s->hbi);
>> +    sector_num = bdrv_dirty_iter_next(s->dbi);
>>       if (sector_num < 0) {
>> -        bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
>> -        sector_num = hbitmap_iter_next(&s->hbi);
>> +        bdrv_set_dirty_iter(s->dbi, 0);
>> +        sector_num = bdrv_dirty_iter_next(s->dbi);
>>           trace_mirror_restart_iter(s, 
>> bdrv_get_dirty_count(s->dirty_bitmap));
>>           assert(sector_num >= 0);
>>       }
>> @@ -334,7 +334,7 @@ static uint64_t coroutine_fn 
>> mirror_iteration(MirrorBlockJob *s)
>>       /* Find the number of consective dirty chunks following the 
>> first dirty
>>        * one, and wait for in flight requests in them. */
>>       while (nb_chunks * sectors_per_chunk < (s->buf_size >> 
>> BDRV_SECTOR_BITS)) {
>> -        int64_t hbitmap_next;
>> +        int64_t next_dirty;
>>           int64_t next_sector = sector_num + nb_chunks * 
>> sectors_per_chunk;
>>           int64_t next_chunk = next_sector / sectors_per_chunk;
>>           if (next_sector >= end ||
>> @@ -345,13 +345,13 @@ static uint64_t coroutine_fn 
>> mirror_iteration(MirrorBlockJob *s)
>>               break;
>>           }
>>   -        hbitmap_next = hbitmap_iter_next(&s->hbi);
>> -        if (hbitmap_next > next_sector || hbitmap_next < 0) {
>> +        next_dirty = bdrv_dirty_iter_next(s->dbi);
>> +        if (next_dirty > next_sector || next_dirty < 0) {
>>               /* The bitmap iterator's cache is stale, refresh it */
>> -            bdrv_set_dirty_iter(&s->hbi, next_sector);
>> -            hbitmap_next = hbitmap_iter_next(&s->hbi);
>> +            bdrv_set_dirty_iter(s->dbi, next_sector);
>> +            next_dirty = bdrv_dirty_iter_next(s->dbi);
>>           }
>> -        assert(hbitmap_next == next_sector);
>> +        assert(next_dirty == next_sector);
>>           nb_chunks++;
>>       }
>>   @@ -601,7 +601,8 @@ static void coroutine_fn mirror_run(void *opaque)
>>           }
>>       }
>>   -    bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
>> +    assert(!s->dbi);
>> +    s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0);
>>       for (;;) {
>>           uint64_t delay_ns = 0;
>>           int64_t cnt;
>> @@ -712,6 +713,7 @@ immediate_exit:
>>       qemu_vfree(s->buf);
>>       g_free(s->cow_bitmap);
>>       g_free(s->in_flight_bitmap);
>> +    bdrv_dirty_iter_free(s->dbi);
>>       bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
>>         data = g_malloc(sizeof(*data));
>> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
>> index 80afe60..2ea601b 100644
>> --- a/include/block/dirty-bitmap.h
>> +++ b/include/block/dirty-bitmap.h
>> @@ -36,8 +36,11 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>>                              int64_t cur_sector, int nr_sectors);
>>   void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>>                                int64_t cur_sector, int nr_sectors);
>> -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct 
>> HBitmapIter *hbi);
>> -void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
>> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
>> +                                         uint64_t first_sector);
>> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
>> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
>> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
>>   int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
>>   void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
>>   diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>> index b113fcf..1b8c30a 100644
>> --- a/include/qemu/typedefs.h
>> +++ b/include/qemu/typedefs.h
>> @@ -11,6 +11,7 @@ typedef struct AioContext AioContext;
>>   typedef struct AllwinnerAHCIState AllwinnerAHCIState;
>>   typedef struct AudioState AudioState;
>>   typedef struct BdrvDirtyBitmap BdrvDirtyBitmap;
>> +typedef struct BdrvDirtyBitmapIter BdrvDirtyBitmapIter;
>>   typedef struct BlockBackend BlockBackend;
>>   typedef struct BlockBackendRootState BlockBackendRootState;
>>   typedef struct BlockDriverState BlockDriverState;
>
>
John Snow July 12, 2016, 10:49 p.m. UTC | #4
On 06/03/2016 12:32 AM, Fam Zheng wrote:
> HBitmap is an implementation detail of block dirty bitmap that should be hidden
> from users. Introduce a BdrvDirtyBitmapIter to encapsulate the underlying
> HBitmapIter.
> 
> A small difference in the interface is, before, an HBitmapIter is initialized
> in place, now the new BdrvDirtyBitmapIter must be dynamically allocated because
> the structure definition is in block/dirty-bitmap.c.
> 
> Two current users are converted too.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/backup.c               | 14 ++++++++------
>  block/dirty-bitmap.c         | 39 +++++++++++++++++++++++++++++++++------
>  block/mirror.c               | 24 +++++++++++++-----------
>  include/block/dirty-bitmap.h |  7 +++++--
>  include/qemu/typedefs.h      |  1 +
>  5 files changed, 60 insertions(+), 25 deletions(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index feeb9f8..ac7ca45 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -317,14 +317,14 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>      int64_t end;
>      int64_t last_cluster = -1;
>      int64_t sectors_per_cluster = cluster_size_sectors(job);
> -    HBitmapIter hbi;
> +    BdrvDirtyBitmapIter *dbi;
>  
>      granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap);
>      clusters_per_iter = MAX((granularity / job->cluster_size), 1);
> -    bdrv_dirty_iter_init(job->sync_bitmap, &hbi);
> +    dbi = bdrv_dirty_iter_new(job->sync_bitmap, 0);
>  
>      /* Find the next dirty sector(s) */
> -    while ((sector = hbitmap_iter_next(&hbi)) != -1) {
> +    while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
>          cluster = sector / sectors_per_cluster;
>  
>          /* Fake progress updates for any clusters we skipped */
> @@ -336,7 +336,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>          for (end = cluster + clusters_per_iter; cluster < end; cluster++) {
>              do {
>                  if (yield_and_check(job)) {
> -                    return ret;
> +                    goto out;
>                  }
>                  ret = backup_do_cow(job, cluster * sectors_per_cluster,
>                                      sectors_per_cluster, &error_is_read,
> @@ -344,7 +344,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>                  if ((ret < 0) &&
>                      backup_error_action(job, error_is_read, -ret) ==
>                      BLOCK_ERROR_ACTION_REPORT) {
> -                    return ret;
> +                    goto out;
>                  }
>              } while (ret < 0);
>          }
> @@ -352,7 +352,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>          /* If the bitmap granularity is smaller than the backup granularity,
>           * we need to advance the iterator pointer to the next cluster. */
>          if (granularity < job->cluster_size) {
> -            bdrv_set_dirty_iter(&hbi, cluster * sectors_per_cluster);
> +            bdrv_set_dirty_iter(dbi, cluster * sectors_per_cluster);
>          }
>  
>          last_cluster = cluster - 1;
> @@ -364,6 +364,8 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>          job->common.offset += ((end - last_cluster - 1) * job->cluster_size);
>      }
>  
> +out:
> +    bdrv_dirty_iter_free(dbi);
>      return ret;
>  }
>  
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 4902ca5..ec073ee 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -42,9 +42,15 @@ struct BdrvDirtyBitmap {
>      char *name;                 /* Optional non-empty unique ID */
>      int64_t size;               /* Size of the bitmap (Number of sectors) */
>      bool disabled;              /* Bitmap is read-only */
> +    int active_iterators;       /* How many iterators are active */
>      QLIST_ENTRY(BdrvDirtyBitmap) list;
>  };
>  
> +struct BdrvDirtyBitmapIter {
> +    HBitmapIter hbi;
> +    BdrvDirtyBitmap *bitmap;
> +};
> +
>  BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
>  {
>      BdrvDirtyBitmap *bm;
> @@ -212,6 +218,7 @@ void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
>  
>      QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
>          assert(!bdrv_dirty_bitmap_frozen(bitmap));
> +        assert(!bitmap->active_iterators);
>          hbitmap_truncate(bitmap->bitmap, size);
>          bitmap->size = size;
>      }
> @@ -224,6 +231,7 @@ static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
>      BdrvDirtyBitmap *bm, *next;
>      QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
>          if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
> +            assert(!bitmap->active_iterators);

No good -- this function is also used to clear out all named bitmaps
belonging to a BDS, so 'bitmap' may be NULL, so this assertion is bad.

Fixing up in my local branch.

--js

>              assert(!bdrv_dirty_bitmap_frozen(bm));
>              QLIST_REMOVE(bm, list);
>              hbitmap_free(bm->bitmap);
> @@ -320,9 +328,29 @@ uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
>      return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
>  }
>  
> -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
> +                                         uint64_t first_sector)
>  {
> -    hbitmap_iter_init(hbi, bitmap->bitmap, 0);
> +    BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
> +    hbitmap_iter_init(&iter->hbi, bitmap->bitmap, first_sector);
> +    iter->bitmap = bitmap;
> +    bitmap->active_iterators++;
> +    return iter;
> +}
> +
> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
> +{
> +    if (!iter) {
> +        return;
> +    }
> +    assert(iter->bitmap->active_iterators > 0);
> +    iter->bitmap->active_iterators--;
> +    g_free(iter);
> +}
> +
> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
> +{
> +    return hbitmap_iter_next(&iter->hbi);
>  }
>  
>  void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> @@ -373,12 +401,11 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
>  }
>  
>  /**
> - * Advance an HBitmapIter to an arbitrary offset.
> + * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
>   */
> -void bdrv_set_dirty_iter(HBitmapIter *hbi, int64_t offset)
> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t sector_num)
>  {
> -    assert(hbi->hb);
> -    hbitmap_iter_init(hbi, hbi->hb, offset);
> +    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, sector_num);
>  }
>  
>  int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
> diff --git a/block/mirror.c b/block/mirror.c
> index 80fd3c7..1d90aa5 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -52,7 +52,7 @@ typedef struct MirrorBlockJob {
>      int64_t bdev_length;
>      unsigned long *cow_bitmap;
>      BdrvDirtyBitmap *dirty_bitmap;
> -    HBitmapIter hbi;
> +    BdrvDirtyBitmapIter *dbi;
>      uint8_t *buf;
>      QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
>      int buf_free_count;
> @@ -317,10 +317,10 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>      int64_t end = s->bdev_length / BDRV_SECTOR_SIZE;
>      int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
>  
> -    sector_num = hbitmap_iter_next(&s->hbi);
> +    sector_num = bdrv_dirty_iter_next(s->dbi);
>      if (sector_num < 0) {
> -        bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
> -        sector_num = hbitmap_iter_next(&s->hbi);
> +        bdrv_set_dirty_iter(s->dbi, 0);
> +        sector_num = bdrv_dirty_iter_next(s->dbi);
>          trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
>          assert(sector_num >= 0);
>      }
> @@ -334,7 +334,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>      /* Find the number of consective dirty chunks following the first dirty
>       * one, and wait for in flight requests in them. */
>      while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) {
> -        int64_t hbitmap_next;
> +        int64_t next_dirty;
>          int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk;
>          int64_t next_chunk = next_sector / sectors_per_chunk;
>          if (next_sector >= end ||
> @@ -345,13 +345,13 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>              break;
>          }
>  
> -        hbitmap_next = hbitmap_iter_next(&s->hbi);
> -        if (hbitmap_next > next_sector || hbitmap_next < 0) {
> +        next_dirty = bdrv_dirty_iter_next(s->dbi);
> +        if (next_dirty > next_sector || next_dirty < 0) {
>              /* The bitmap iterator's cache is stale, refresh it */
> -            bdrv_set_dirty_iter(&s->hbi, next_sector);
> -            hbitmap_next = hbitmap_iter_next(&s->hbi);
> +            bdrv_set_dirty_iter(s->dbi, next_sector);
> +            next_dirty = bdrv_dirty_iter_next(s->dbi);
>          }
> -        assert(hbitmap_next == next_sector);
> +        assert(next_dirty == next_sector);
>          nb_chunks++;
>      }
>  
> @@ -601,7 +601,8 @@ static void coroutine_fn mirror_run(void *opaque)
>          }
>      }
>  
> -    bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
> +    assert(!s->dbi);
> +    s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0);
>      for (;;) {
>          uint64_t delay_ns = 0;
>          int64_t cnt;
> @@ -712,6 +713,7 @@ immediate_exit:
>      qemu_vfree(s->buf);
>      g_free(s->cow_bitmap);
>      g_free(s->in_flight_bitmap);
> +    bdrv_dirty_iter_free(s->dbi);
>      bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
>  
>      data = g_malloc(sizeof(*data));
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index 80afe60..2ea601b 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -36,8 +36,11 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>                             int64_t cur_sector, int nr_sectors);
>  void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>                               int64_t cur_sector, int nr_sectors);
> -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
> -void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
> +                                         uint64_t first_sector);
> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
>  int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
>  void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
>  
> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
> index b113fcf..1b8c30a 100644
> --- a/include/qemu/typedefs.h
> +++ b/include/qemu/typedefs.h
> @@ -11,6 +11,7 @@ typedef struct AioContext AioContext;
>  typedef struct AllwinnerAHCIState AllwinnerAHCIState;
>  typedef struct AudioState AudioState;
>  typedef struct BdrvDirtyBitmap BdrvDirtyBitmap;
> +typedef struct BdrvDirtyBitmapIter BdrvDirtyBitmapIter;
>  typedef struct BlockBackend BlockBackend;
>  typedef struct BlockBackendRootState BlockBackendRootState;
>  typedef struct BlockDriverState BlockDriverState;
>
Vladimir Sementsov-Ogievskiy July 13, 2016, 7:57 a.m. UTC | #5
On 13.07.2016 01:49, John Snow wrote:
>
> On 06/03/2016 12:32 AM, Fam Zheng wrote:
>> HBitmap is an implementation detail of block dirty bitmap that should be hidden
>> from users. Introduce a BdrvDirtyBitmapIter to encapsulate the underlying
>> HBitmapIter.
>>
>> A small difference in the interface is, before, an HBitmapIter is initialized
>> in place, now the new BdrvDirtyBitmapIter must be dynamically allocated because
>> the structure definition is in block/dirty-bitmap.c.
>>
>> Two current users are converted too.
>>
>> Signed-off-by: Fam Zheng <famz@redhat.com>
>> ---
>>   block/backup.c               | 14 ++++++++------
>>   block/dirty-bitmap.c         | 39 +++++++++++++++++++++++++++++++++------
>>   block/mirror.c               | 24 +++++++++++++-----------
>>   include/block/dirty-bitmap.h |  7 +++++--
>>   include/qemu/typedefs.h      |  1 +
>>   5 files changed, 60 insertions(+), 25 deletions(-)
>>
>> diff --git a/block/backup.c b/block/backup.c
>> index feeb9f8..ac7ca45 100644
>> --- a/block/backup.c
>> +++ b/block/backup.c
>> @@ -317,14 +317,14 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>>       int64_t end;
>>       int64_t last_cluster = -1;
>>       int64_t sectors_per_cluster = cluster_size_sectors(job);
>> -    HBitmapIter hbi;
>> +    BdrvDirtyBitmapIter *dbi;
>>   
>>       granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap);
>>       clusters_per_iter = MAX((granularity / job->cluster_size), 1);
>> -    bdrv_dirty_iter_init(job->sync_bitmap, &hbi);
>> +    dbi = bdrv_dirty_iter_new(job->sync_bitmap, 0);
>>   
>>       /* Find the next dirty sector(s) */
>> -    while ((sector = hbitmap_iter_next(&hbi)) != -1) {
>> +    while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
>>           cluster = sector / sectors_per_cluster;
>>   
>>           /* Fake progress updates for any clusters we skipped */
>> @@ -336,7 +336,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>>           for (end = cluster + clusters_per_iter; cluster < end; cluster++) {
>>               do {
>>                   if (yield_and_check(job)) {
>> -                    return ret;
>> +                    goto out;
>>                   }
>>                   ret = backup_do_cow(job, cluster * sectors_per_cluster,
>>                                       sectors_per_cluster, &error_is_read,
>> @@ -344,7 +344,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>>                   if ((ret < 0) &&
>>                       backup_error_action(job, error_is_read, -ret) ==
>>                       BLOCK_ERROR_ACTION_REPORT) {
>> -                    return ret;
>> +                    goto out;
>>                   }
>>               } while (ret < 0);
>>           }
>> @@ -352,7 +352,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>>           /* If the bitmap granularity is smaller than the backup granularity,
>>            * we need to advance the iterator pointer to the next cluster. */
>>           if (granularity < job->cluster_size) {
>> -            bdrv_set_dirty_iter(&hbi, cluster * sectors_per_cluster);
>> +            bdrv_set_dirty_iter(dbi, cluster * sectors_per_cluster);
>>           }
>>   
>>           last_cluster = cluster - 1;
>> @@ -364,6 +364,8 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>>           job->common.offset += ((end - last_cluster - 1) * job->cluster_size);
>>       }
>>   
>> +out:
>> +    bdrv_dirty_iter_free(dbi);
>>       return ret;
>>   }
>>   
>> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
>> index 4902ca5..ec073ee 100644
>> --- a/block/dirty-bitmap.c
>> +++ b/block/dirty-bitmap.c
>> @@ -42,9 +42,15 @@ struct BdrvDirtyBitmap {
>>       char *name;                 /* Optional non-empty unique ID */
>>       int64_t size;               /* Size of the bitmap (Number of sectors) */
>>       bool disabled;              /* Bitmap is read-only */
>> +    int active_iterators;       /* How many iterators are active */
>>       QLIST_ENTRY(BdrvDirtyBitmap) list;
>>   };
>>   
>> +struct BdrvDirtyBitmapIter {
>> +    HBitmapIter hbi;
>> +    BdrvDirtyBitmap *bitmap;
>> +};
>> +
>>   BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
>>   {
>>       BdrvDirtyBitmap *bm;
>> @@ -212,6 +218,7 @@ void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
>>   
>>       QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
>>           assert(!bdrv_dirty_bitmap_frozen(bitmap));
>> +        assert(!bitmap->active_iterators);
>>           hbitmap_truncate(bitmap->bitmap, size);
>>           bitmap->size = size;
>>       }
>> @@ -224,6 +231,7 @@ static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
>>       BdrvDirtyBitmap *bm, *next;
>>       QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
>>           if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
>> +            assert(!bitmap->active_iterators);
> No good -- this function is also used to clear out all named bitmaps
> belonging to a BDS, so 'bitmap' may be NULL, so this assertion is bad.

Just a note about this. I do not like this hidden behaviour of 
release_bitmap, as it more native for freeing functions to do nothing 
with NULL pointer.. g_free(NULL) do not free all allocations))).. If 
someone agrees, this may be better to be changed.

>
> Fixing up in my local branch.
>
> --js
>
>>               assert(!bdrv_dirty_bitmap_frozen(bm));
>>               QLIST_REMOVE(bm, list);
>>               hbitmap_free(bm->bitmap);
>> @@ -320,9 +328,29 @@ uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
>>       return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
>>   }
>>   
>> -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
>> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
>> +                                         uint64_t first_sector)
>>   {
>> -    hbitmap_iter_init(hbi, bitmap->bitmap, 0);
>> +    BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
>> +    hbitmap_iter_init(&iter->hbi, bitmap->bitmap, first_sector);
>> +    iter->bitmap = bitmap;
>> +    bitmap->active_iterators++;
>> +    return iter;
>> +}
>> +
>> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
>> +{
>> +    if (!iter) {
>> +        return;
>> +    }
>> +    assert(iter->bitmap->active_iterators > 0);
>> +    iter->bitmap->active_iterators--;
>> +    g_free(iter);
>> +}
>> +
>> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
>> +{
>> +    return hbitmap_iter_next(&iter->hbi);
>>   }
>>   
>>   void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>> @@ -373,12 +401,11 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
>>   }
>>   
>>   /**
>> - * Advance an HBitmapIter to an arbitrary offset.
>> + * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
>>    */
>> -void bdrv_set_dirty_iter(HBitmapIter *hbi, int64_t offset)
>> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t sector_num)
>>   {
>> -    assert(hbi->hb);
>> -    hbitmap_iter_init(hbi, hbi->hb, offset);
>> +    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, sector_num);
>>   }
>>   
>>   int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
>> diff --git a/block/mirror.c b/block/mirror.c
>> index 80fd3c7..1d90aa5 100644
>> --- a/block/mirror.c
>> +++ b/block/mirror.c
>> @@ -52,7 +52,7 @@ typedef struct MirrorBlockJob {
>>       int64_t bdev_length;
>>       unsigned long *cow_bitmap;
>>       BdrvDirtyBitmap *dirty_bitmap;
>> -    HBitmapIter hbi;
>> +    BdrvDirtyBitmapIter *dbi;
>>       uint8_t *buf;
>>       QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
>>       int buf_free_count;
>> @@ -317,10 +317,10 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>>       int64_t end = s->bdev_length / BDRV_SECTOR_SIZE;
>>       int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
>>   
>> -    sector_num = hbitmap_iter_next(&s->hbi);
>> +    sector_num = bdrv_dirty_iter_next(s->dbi);
>>       if (sector_num < 0) {
>> -        bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
>> -        sector_num = hbitmap_iter_next(&s->hbi);
>> +        bdrv_set_dirty_iter(s->dbi, 0);
>> +        sector_num = bdrv_dirty_iter_next(s->dbi);
>>           trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
>>           assert(sector_num >= 0);
>>       }
>> @@ -334,7 +334,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>>       /* Find the number of consective dirty chunks following the first dirty
>>        * one, and wait for in flight requests in them. */
>>       while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) {
>> -        int64_t hbitmap_next;
>> +        int64_t next_dirty;
>>           int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk;
>>           int64_t next_chunk = next_sector / sectors_per_chunk;
>>           if (next_sector >= end ||
>> @@ -345,13 +345,13 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>>               break;
>>           }
>>   
>> -        hbitmap_next = hbitmap_iter_next(&s->hbi);
>> -        if (hbitmap_next > next_sector || hbitmap_next < 0) {
>> +        next_dirty = bdrv_dirty_iter_next(s->dbi);
>> +        if (next_dirty > next_sector || next_dirty < 0) {
>>               /* The bitmap iterator's cache is stale, refresh it */
>> -            bdrv_set_dirty_iter(&s->hbi, next_sector);
>> -            hbitmap_next = hbitmap_iter_next(&s->hbi);
>> +            bdrv_set_dirty_iter(s->dbi, next_sector);
>> +            next_dirty = bdrv_dirty_iter_next(s->dbi);
>>           }
>> -        assert(hbitmap_next == next_sector);
>> +        assert(next_dirty == next_sector);
>>           nb_chunks++;
>>       }
>>   
>> @@ -601,7 +601,8 @@ static void coroutine_fn mirror_run(void *opaque)
>>           }
>>       }
>>   
>> -    bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
>> +    assert(!s->dbi);
>> +    s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0);
>>       for (;;) {
>>           uint64_t delay_ns = 0;
>>           int64_t cnt;
>> @@ -712,6 +713,7 @@ immediate_exit:
>>       qemu_vfree(s->buf);
>>       g_free(s->cow_bitmap);
>>       g_free(s->in_flight_bitmap);
>> +    bdrv_dirty_iter_free(s->dbi);
>>       bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
>>   
>>       data = g_malloc(sizeof(*data));
>> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
>> index 80afe60..2ea601b 100644
>> --- a/include/block/dirty-bitmap.h
>> +++ b/include/block/dirty-bitmap.h
>> @@ -36,8 +36,11 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>>                              int64_t cur_sector, int nr_sectors);
>>   void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>>                                int64_t cur_sector, int nr_sectors);
>> -void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
>> -void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
>> +BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
>> +                                         uint64_t first_sector);
>> +void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
>> +int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
>> +void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
>>   int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
>>   void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
>>   
>> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>> index b113fcf..1b8c30a 100644
>> --- a/include/qemu/typedefs.h
>> +++ b/include/qemu/typedefs.h
>> @@ -11,6 +11,7 @@ typedef struct AioContext AioContext;
>>   typedef struct AllwinnerAHCIState AllwinnerAHCIState;
>>   typedef struct AudioState AudioState;
>>   typedef struct BdrvDirtyBitmap BdrvDirtyBitmap;
>> +typedef struct BdrvDirtyBitmapIter BdrvDirtyBitmapIter;
>>   typedef struct BlockBackend BlockBackend;
>>   typedef struct BlockBackendRootState BlockBackendRootState;
>>   typedef struct BlockDriverState BlockDriverState;
>>
Max Reitz July 13, 2016, 10:10 a.m. UTC | #6
On 13.07.2016 09:57, Vladimir Sementsov-Ogievskiy wrote:
> On 13.07.2016 01:49, John Snow wrote:
>>
>> On 06/03/2016 12:32 AM, Fam Zheng wrote:
>>> HBitmap is an implementation detail of block dirty bitmap that should
>>> be hidden
>>> from users. Introduce a BdrvDirtyBitmapIter to encapsulate the
>>> underlying
>>> HBitmapIter.
>>>
>>> A small difference in the interface is, before, an HBitmapIter is
>>> initialized
>>> in place, now the new BdrvDirtyBitmapIter must be dynamically
>>> allocated because
>>> the structure definition is in block/dirty-bitmap.c.
>>>
>>> Two current users are converted too.
>>>
>>> Signed-off-by: Fam Zheng <famz@redhat.com>
>>> ---
>>>   block/backup.c               | 14 ++++++++------
>>>   block/dirty-bitmap.c         | 39
>>> +++++++++++++++++++++++++++++++++------
>>>   block/mirror.c               | 24 +++++++++++++-----------
>>>   include/block/dirty-bitmap.h |  7 +++++--
>>>   include/qemu/typedefs.h      |  1 +
>>>   5 files changed, 60 insertions(+), 25 deletions(-)
>>>

[...]

>>> @@ -224,6 +231,7 @@ static void
>>> bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
>>>       BdrvDirtyBitmap *bm, *next;
>>>       QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
>>>           if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
>>> +            assert(!bitmap->active_iterators);
>> No good -- this function is also used to clear out all named bitmaps
>> belonging to a BDS, so 'bitmap' may be NULL, so this assertion is bad.
> 
> Just a note about this. I do not like this hidden behaviour of
> release_bitmap, as it more native for freeing functions to do nothing
> with NULL pointer.. g_free(NULL) do not free all allocations))).. If
> someone agrees, this may be better to be changed.

The function is not called "bdrv_release_dirty_bitmap()", though, but
"bdrv_do_release_matching_dirty_bitmap()". The "do" means that it's an
internal function, called only by bdrv_release_dirty_bitmap() (aha!) and
bdrv_release_named_dirty_bitmaps(); and the "matching" means that if you
pass NULL, it'll release all bitmaps.

What we could do is make bdrv_release_dirty_bitmap() a no-op if NULL is
passed, or add an assertion that the argument is not NULL. I'd be fine
with either, but I don't think bdrv_do_release_matching_dirty_bitmap()
needs to be adjusted.

Max
diff mbox

Patch

diff --git a/block/backup.c b/block/backup.c
index feeb9f8..ac7ca45 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -317,14 +317,14 @@  static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
     int64_t end;
     int64_t last_cluster = -1;
     int64_t sectors_per_cluster = cluster_size_sectors(job);
-    HBitmapIter hbi;
+    BdrvDirtyBitmapIter *dbi;
 
     granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap);
     clusters_per_iter = MAX((granularity / job->cluster_size), 1);
-    bdrv_dirty_iter_init(job->sync_bitmap, &hbi);
+    dbi = bdrv_dirty_iter_new(job->sync_bitmap, 0);
 
     /* Find the next dirty sector(s) */
-    while ((sector = hbitmap_iter_next(&hbi)) != -1) {
+    while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
         cluster = sector / sectors_per_cluster;
 
         /* Fake progress updates for any clusters we skipped */
@@ -336,7 +336,7 @@  static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
         for (end = cluster + clusters_per_iter; cluster < end; cluster++) {
             do {
                 if (yield_and_check(job)) {
-                    return ret;
+                    goto out;
                 }
                 ret = backup_do_cow(job, cluster * sectors_per_cluster,
                                     sectors_per_cluster, &error_is_read,
@@ -344,7 +344,7 @@  static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
                 if ((ret < 0) &&
                     backup_error_action(job, error_is_read, -ret) ==
                     BLOCK_ERROR_ACTION_REPORT) {
-                    return ret;
+                    goto out;
                 }
             } while (ret < 0);
         }
@@ -352,7 +352,7 @@  static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
         /* If the bitmap granularity is smaller than the backup granularity,
          * we need to advance the iterator pointer to the next cluster. */
         if (granularity < job->cluster_size) {
-            bdrv_set_dirty_iter(&hbi, cluster * sectors_per_cluster);
+            bdrv_set_dirty_iter(dbi, cluster * sectors_per_cluster);
         }
 
         last_cluster = cluster - 1;
@@ -364,6 +364,8 @@  static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
         job->common.offset += ((end - last_cluster - 1) * job->cluster_size);
     }
 
+out:
+    bdrv_dirty_iter_free(dbi);
     return ret;
 }
 
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 4902ca5..ec073ee 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -42,9 +42,15 @@  struct BdrvDirtyBitmap {
     char *name;                 /* Optional non-empty unique ID */
     int64_t size;               /* Size of the bitmap (Number of sectors) */
     bool disabled;              /* Bitmap is read-only */
+    int active_iterators;       /* How many iterators are active */
     QLIST_ENTRY(BdrvDirtyBitmap) list;
 };
 
+struct BdrvDirtyBitmapIter {
+    HBitmapIter hbi;
+    BdrvDirtyBitmap *bitmap;
+};
+
 BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
 {
     BdrvDirtyBitmap *bm;
@@ -212,6 +218,7 @@  void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
 
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
         assert(!bdrv_dirty_bitmap_frozen(bitmap));
+        assert(!bitmap->active_iterators);
         hbitmap_truncate(bitmap->bitmap, size);
         bitmap->size = size;
     }
@@ -224,6 +231,7 @@  static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
     BdrvDirtyBitmap *bm, *next;
     QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
         if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
+            assert(!bitmap->active_iterators);
             assert(!bdrv_dirty_bitmap_frozen(bm));
             QLIST_REMOVE(bm, list);
             hbitmap_free(bm->bitmap);
@@ -320,9 +328,29 @@  uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
     return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
 }
 
-void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
+BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
+                                         uint64_t first_sector)
 {
-    hbitmap_iter_init(hbi, bitmap->bitmap, 0);
+    BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
+    hbitmap_iter_init(&iter->hbi, bitmap->bitmap, first_sector);
+    iter->bitmap = bitmap;
+    bitmap->active_iterators++;
+    return iter;
+}
+
+void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
+{
+    if (!iter) {
+        return;
+    }
+    assert(iter->bitmap->active_iterators > 0);
+    iter->bitmap->active_iterators--;
+    g_free(iter);
+}
+
+int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
+{
+    return hbitmap_iter_next(&iter->hbi);
 }
 
 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
@@ -373,12 +401,11 @@  void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
 }
 
 /**
- * Advance an HBitmapIter to an arbitrary offset.
+ * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
  */
-void bdrv_set_dirty_iter(HBitmapIter *hbi, int64_t offset)
+void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t sector_num)
 {
-    assert(hbi->hb);
-    hbitmap_iter_init(hbi, hbi->hb, offset);
+    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, sector_num);
 }
 
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
diff --git a/block/mirror.c b/block/mirror.c
index 80fd3c7..1d90aa5 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -52,7 +52,7 @@  typedef struct MirrorBlockJob {
     int64_t bdev_length;
     unsigned long *cow_bitmap;
     BdrvDirtyBitmap *dirty_bitmap;
-    HBitmapIter hbi;
+    BdrvDirtyBitmapIter *dbi;
     uint8_t *buf;
     QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
     int buf_free_count;
@@ -317,10 +317,10 @@  static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
     int64_t end = s->bdev_length / BDRV_SECTOR_SIZE;
     int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
 
-    sector_num = hbitmap_iter_next(&s->hbi);
+    sector_num = bdrv_dirty_iter_next(s->dbi);
     if (sector_num < 0) {
-        bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
-        sector_num = hbitmap_iter_next(&s->hbi);
+        bdrv_set_dirty_iter(s->dbi, 0);
+        sector_num = bdrv_dirty_iter_next(s->dbi);
         trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
         assert(sector_num >= 0);
     }
@@ -334,7 +334,7 @@  static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
     /* Find the number of consective dirty chunks following the first dirty
      * one, and wait for in flight requests in them. */
     while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) {
-        int64_t hbitmap_next;
+        int64_t next_dirty;
         int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk;
         int64_t next_chunk = next_sector / sectors_per_chunk;
         if (next_sector >= end ||
@@ -345,13 +345,13 @@  static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
             break;
         }
 
-        hbitmap_next = hbitmap_iter_next(&s->hbi);
-        if (hbitmap_next > next_sector || hbitmap_next < 0) {
+        next_dirty = bdrv_dirty_iter_next(s->dbi);
+        if (next_dirty > next_sector || next_dirty < 0) {
             /* The bitmap iterator's cache is stale, refresh it */
-            bdrv_set_dirty_iter(&s->hbi, next_sector);
-            hbitmap_next = hbitmap_iter_next(&s->hbi);
+            bdrv_set_dirty_iter(s->dbi, next_sector);
+            next_dirty = bdrv_dirty_iter_next(s->dbi);
         }
-        assert(hbitmap_next == next_sector);
+        assert(next_dirty == next_sector);
         nb_chunks++;
     }
 
@@ -601,7 +601,8 @@  static void coroutine_fn mirror_run(void *opaque)
         }
     }
 
-    bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
+    assert(!s->dbi);
+    s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0);
     for (;;) {
         uint64_t delay_ns = 0;
         int64_t cnt;
@@ -712,6 +713,7 @@  immediate_exit:
     qemu_vfree(s->buf);
     g_free(s->cow_bitmap);
     g_free(s->in_flight_bitmap);
+    bdrv_dirty_iter_free(s->dbi);
     bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
 
     data = g_malloc(sizeof(*data));
diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 80afe60..2ea601b 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -36,8 +36,11 @@  void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors);
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                              int64_t cur_sector, int nr_sectors);
-void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
-void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
+BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
+                                         uint64_t first_sector);
+void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
+int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
+void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
 
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index b113fcf..1b8c30a 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -11,6 +11,7 @@  typedef struct AioContext AioContext;
 typedef struct AllwinnerAHCIState AllwinnerAHCIState;
 typedef struct AudioState AudioState;
 typedef struct BdrvDirtyBitmap BdrvDirtyBitmap;
+typedef struct BdrvDirtyBitmapIter BdrvDirtyBitmapIter;
 typedef struct BlockBackend BlockBackend;
 typedef struct BlockBackendRootState BlockBackendRootState;
 typedef struct BlockDriverState BlockDriverState;