06.06.2019 21:41, John Snow wrote:
> Instead of bdrv_can_store_new_bitmap, rework this as
> bdrv_add_persistent_dirty_bitmap. This makes a more obvious symmetry
> with bdrv_remove_persistent_dirty_bitmap. Most importantly, we are free
> to modify the driver state because we know we ARE adding a bitmap
> instead of simply being asked if we CAN store one.
>
> As part of this symmetry, move this function next to
> bdrv_remove_persistent_bitmap in block/dirty-bitmap.c.
>
> To cement this semantic distinction, use a bitmap object instead of the
> (name, granularity) pair as this allows us to set persistence as a
> condition of the "add" succeeding.
>
> Notably, the qcow2 implementation still does not actually store the new
> bitmap at add time, but merely ensures that it will be able to at store
> time.
>
> Signed-off-by: John Snow <js...@redhat.com>
> ---
> block/qcow2.h | 5 ++---
> include/block/block.h | 2 --
> include/block/block_int.h | 5 ++---
> include/block/dirty-bitmap.h | 3 +++
> block.c | 22 ---------------------
> block/dirty-bitmap.c | 38 ++++++++++++++++++++++++++++++++++++
> block/qcow2-bitmap.c | 24 ++++++++++++++---------
> block/qcow2.c | 2 +-
> blockdev.c | 19 +++++++-----------
> 9 files changed, 68 insertions(+), 52 deletions(-)
>
> diff --git a/block/qcow2.h b/block/qcow2.h
> index fc1b0d3c1e..95d723d3c0 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -742,9 +742,8 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error
> **errp);
> int qcow2_truncate_bitmaps_check(BlockDriverState *bs, Error **errp);
> void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error
> **errp);
> int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
> -bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
> - const char *name,
> - uint32_t granularity,
> +int qcow2_add_persistent_dirty_bitmap(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap,
> Error **errp);
> void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
> const char *name,
> diff --git a/include/block/block.h b/include/block/block.h
> index f9415ed740..6d520f3b59 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -683,8 +683,6 @@ void bdrv_add_child(BlockDriverState *parent,
> BlockDriverState *child,
> Error **errp);
> void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error
> **errp);
>
> -bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
> - uint32_t granularity, Error **errp);
> /**
> *
> * bdrv_register_buf/bdrv_unregister_buf:
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 06df2bda1b..93bbb66cd0 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -537,9 +537,8 @@ struct BlockDriver {
> * field of BlockDirtyBitmap's in case of success.
> */
> int (*bdrv_reopen_bitmaps_rw)(BlockDriverState *bs, Error **errp);
> - bool (*bdrv_can_store_new_dirty_bitmap)(BlockDriverState *bs,
> - const char *name,
> - uint32_t granularity,
> + int (*bdrv_add_persistent_dirty_bitmap)(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap,
> Error **errp);
> void (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs,
> const char *name,
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index 8044ace63e..c37edbe05f 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -38,6 +38,9 @@ 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);
> +int bdrv_add_persistent_dirty_bitmap(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap,
> + Error **errp);
> void bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs,
> const char *name,
> Error **errp);
> diff --git a/block.c b/block.c
> index e3e77feee0..6aec36b7c9 100644
> --- a/block.c
> +++ b/block.c
> @@ -6379,25 +6379,3 @@ void bdrv_del_child(BlockDriverState *parent_bs,
> BdrvChild *child, Error **errp)
>
> parent_bs->drv->bdrv_del_child(parent_bs, child, errp);
> }
> -
> -bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
> - uint32_t granularity, Error **errp)
> -{
> - BlockDriver *drv = bs->drv;
> -
> - if (!drv) {
> - error_setg_errno(errp, ENOMEDIUM,
> - "Can't store persistent bitmaps to %s",
> - bdrv_get_device_or_node_name(bs));
> - return false;
> - }
> -
> - if (!drv->bdrv_can_store_new_dirty_bitmap) {
> - error_setg_errno(errp, ENOTSUP,
> - "Can't store persistent bitmaps to %s",
> - bdrv_get_device_or_node_name(bs));
> - return false;
> - }
> -
> - return drv->bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp);
> -}
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 49646a30e6..615f8480b2 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -466,6 +466,44 @@ void
> bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs,
> }
> }
>
> +int bdrv_add_persistent_dirty_bitmap(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap,
> + Error **errp)
strange thing for me: "bitmap" in function name is _not_ the same
thing as @bitmap argument.. as if it the same,
function adds "persistent bitmap", but @bitmap is not persistent yet,
so may be function, don't add persistent bitmap, but marks bitmap persistent?
Ok, I can think of it like "add persistent dirty bitmap to driver. if succeed,
set
bitmap.persistent flag"
> +{
> + BlockDriver *drv = bs->drv;
> + int ret;
> +
> + if (bdrv_dirty_bitmap_get_persistence(bitmap)) {
> + error_setg(errp, "Bitmap '%s' is already persistent, "
> + "and cannot be re-added to node '%s'",
> + bdrv_dirty_bitmap_name(bitmap),
> + bdrv_get_device_or_node_name(bs));
> + return -EINVAL;
> + }
> +
> + if (!drv) {
> + error_setg_errno(errp, ENOMEDIUM,
> + "Can't store persistent bitmaps to %s",
> + bdrv_get_device_or_node_name(bs));
> + return -ENOMEDIUM;
> + }
> +
> + if (!drv->bdrv_add_persistent_dirty_bitmap) {
> + error_setg_errno(errp, ENOTSUP,
> + "Can't store persistent bitmaps to %s",
> + bdrv_get_device_or_node_name(bs));
> + return -ENOTSUP;
> + }
> +
> + ret = drv->bdrv_add_persistent_dirty_bitmap(bs, bitmap, errp);
> + if (ret == 0) {
> + bdrv_dirty_bitmap_set_persistence(bitmap, true);
> + }
> +
> + return ret;
> +}
> +
> +
> void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
> {
> bdrv_dirty_bitmap_lock(bitmap);
> diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
> index 83aee1a42a..c3a72ca782 100644
> --- a/block/qcow2-bitmap.c
> +++ b/block/qcow2-bitmap.c
> @@ -1607,14 +1607,16 @@ int qcow2_reopen_bitmaps_ro(BlockDriverState *bs,
> Error **errp)
> return 0;
> }
>
> -bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
> - const char *name,
> - uint32_t granularity,
> +int qcow2_add_persistent_dirty_bitmap(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap,
> Error **errp)
> {
> BDRVQcow2State *s = bs->opaque;
> bool found;
> Qcow2BitmapList *bm_list;
> + const char *name = bdrv_dirty_bitmap_name(bitmap);
> + uint32_t granularity = bdrv_dirty_bitmap_granularity(bitmap);
> + int ret = 0;
dead assignment
>
> if (s->qcow_version < 3) {
> /* Without autoclear_features, we would always have to assume
> @@ -1623,20 +1625,23 @@ bool
> qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
> * have to drop all dirty bitmaps (defeating their purpose).
> */
> error_setg(errp, "Cannot store dirty bitmaps in qcow2 v2 files");
> + ret = -ENOTSUP;
> goto fail;
> }
>
> - if (check_constraints_on_bitmap(bs, name, granularity, errp) != 0) {
> + ret = check_constraints_on_bitmap(bs, name, granularity, errp);
> + if (ret) {
hmm, in other places you prefere
if ((ret = ...)) {
syntax
> goto fail;
> }
>
> if (s->nb_bitmaps == 0) {
> - return true;
> + return 0;
> }
>
> if (s->nb_bitmaps >= QCOW2_MAX_BITMAPS) {
> error_setg(errp,
> "Maximum number of persistent bitmaps is already
> reached");
> + ret = -EOVERFLOW;
> goto fail;
> }
>
> @@ -1644,24 +1649,25 @@ bool
> qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
> QCOW2_MAX_BITMAP_DIRECTORY_SIZE)
> {
> error_setg(errp, "Not enough space in the bitmap directory");
> + ret = -EOVERFLOW;
> goto fail;
> }
>
> - if (bitmap_list_load(bs, &bm_list, errp)) {
> + if ((ret = bitmap_list_load(bs, &bm_list, errp))) {
interesting, now we load all bitmaps, so, may be, we don't need to load list
every time,
but may use bs.dirty_bitmaps to check such things.. But it seems unsafe
> goto fail;
> }
>
> found = find_bitmap_by_name(bm_list, name);
> bitmap_list_free(bm_list);
> if (found) {
> + ret = -EEXIST;
> error_setg(errp, "Bitmap with the same name is already stored");
> goto fail;
> }
>
> - return true;
> -
> + return 0;
> fail:
> error_prepend(errp, "Can't make bitmap '%s' persistent in '%s': ",
> name, bdrv_get_device_or_node_name(bs));
didn't you consider to move this error_prepend to caller and drop all these
gotos?
> - return false;
> + return ret;
> }
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 9396d490d5..1c78eba71b 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -5229,7 +5229,7 @@ BlockDriver bdrv_qcow2 = {
> .bdrv_attach_aio_context = qcow2_attach_aio_context,
>
> .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw,
> - .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap,
> + .bdrv_add_persistent_dirty_bitmap = qcow2_add_persistent_dirty_bitmap,
> .bdrv_remove_persistent_dirty_bitmap =
> qcow2_remove_persistent_dirty_bitmap,
> };
>
> diff --git a/blockdev.c b/blockdev.c
> index 3f44b891eb..169a8da831 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2851,26 +2851,21 @@ void qmp_block_dirty_bitmap_add(const char *node,
> const char *name,
> disabled = false;
> }
>
> - if (persistent) {
> - aio_context = bdrv_get_aio_context(bs);
> - aio_context_acquire(aio_context);
> - if (!bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp)) {
> - goto out;
> - }
> - }
> -
> bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
> if (bitmap == NULL) {
> - goto out;
> + return;
> }
>
> if (disabled) {
> bdrv_disable_dirty_bitmap(bitmap);
> }
>
> - bdrv_dirty_bitmap_set_persistence(bitmap, persistent);
> - out:
> - if (aio_context) {
> + if (persistent) {
Good thing. I suggest to define aio_context in this block too.
> + aio_context = bdrv_get_aio_context(bs);
> + aio_context_acquire(aio_context);
> + if (bdrv_add_persistent_dirty_bitmap(bs, bitmap, errp)) {
> + bdrv_release_dirty_bitmap(bs, bitmap);
> + }
> aio_context_release(aio_context);
> }
> }
>
With some my suggestions or without:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
--
Best regards,
Vladimir
