Commit fb933437 authored by Fam Zheng's avatar Fam Zheng Committed by Max Reitz
Browse files

block: Support meta dirty bitmap 



The added group of operations enables tracking of the changed bits in
the dirty bitmap.

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarJohn Snow <jsnow@redhat.com>
Message-id: 1476395910-8697-5-git-send-email-jsnow@redhat.com
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 4b62818a

block/dirty-bitmap.c

+52 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
 */

struct BdrvDirtyBitmap {

    HBitmap *bitmap;            /* Dirty sector bitmap implementation */

    HBitmap *meta;              /* Meta dirty bitmap */

    BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */

    char *name;                 /* Optional non-empty unique ID */

    int64_t size;               /* Size of the bitmap (Number of sectors) */
@@ -103,6 +104,56 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, 
    return bitmap;

}



/* bdrv_create_meta_dirty_bitmap

 *

 * Create a meta dirty bitmap that tracks the changes of bits in @bitmap. I.e.

 * when a dirty status bit in @bitmap is changed (either from reset to set or

 * the other way around), its respective meta dirty bitmap bit will be marked

 * dirty as well.

 *

 * @bitmap: the block dirty bitmap for which to create a meta dirty bitmap.

 * @chunk_size: how many bytes of bitmap data does each bit in the meta bitmap

 * track.

 */

void bdrv_create_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap,

                                   int chunk_size)

{

    assert(!bitmap->meta);

    bitmap->meta = hbitmap_create_meta(bitmap->bitmap,

                                       chunk_size * BITS_PER_BYTE);

}



void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)

{

    assert(bitmap->meta);

    hbitmap_free_meta(bitmap->bitmap);

    bitmap->meta = NULL;

}



int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,

                               BdrvDirtyBitmap *bitmap, int64_t sector,

                               int nb_sectors)

{

    uint64_t i;

    int sectors_per_bit = 1 << hbitmap_granularity(bitmap->meta);



    /* To optimize: we can make hbitmap to internally check the range in a

     * coarse level, or at least do it word by word. */

    for (i = sector; i < sector + nb_sectors; i += sectors_per_bit) {

        if (hbitmap_get(bitmap->meta, i)) {

            return true;

        }

    }

    return false;

}



void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,

                                  BdrvDirtyBitmap *bitmap, int64_t sector,

                                  int nb_sectors)

{

    hbitmap_reset(bitmap->meta, sector, nb_sectors);

}



bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap)

{

    return bitmap->successor;
@@ -233,6 +284,7 @@ static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs, 
        if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {

            assert(!bm->active_iterators);

            assert(!bdrv_dirty_bitmap_frozen(bm));

            assert(!bm->meta);

            QLIST_REMOVE(bm, list);

            hbitmap_free(bm->bitmap);

            g_free(bm->name);

include/block/dirty-bitmap.h

+9 −0
Original line number Diff line number Diff line
@@ -8,6 +8,9 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, 
                                          uint32_t granularity,

                                          const char *name,

                                          Error **errp);

void bdrv_create_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap,

                                   int chunk_size);

void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap);

int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs,

                                       BdrvDirtyBitmap *bitmap,

                                       Error **errp);
@@ -36,6 +39,12 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap, 
                           int64_t cur_sector, int64_t nr_sectors);

void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,

                             int64_t cur_sector, int64_t nr_sectors);

int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,

                               BdrvDirtyBitmap *bitmap, int64_t sector,

                               int nb_sectors);

void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,

                                  BdrvDirtyBitmap *bitmap, int64_t sector,

                                  int nb_sectors);

BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,

                                         uint64_t first_sector);

void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);