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Re: [PATCH v2 09/13] block/qcow2-bitmap: improve qcow2_load_dirty_bitmap
From: |
Greg Kurz |
Subject: |
Re: [PATCH v2 09/13] block/qcow2-bitmap: improve qcow2_load_dirty_bitmaps() interface |
Date: |
Fri, 18 Sep 2020 17:15:13 +0200 |
On Thu, 17 Sep 2020 22:55:15 +0300
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:
> It's recommended for bool functions with errp to return true on success
> and false on failure. Non-standard interfaces don't help to understand
> the code. The change is also needed to reduce error propagation.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
With the documentation change suggested by Berto,
Reviewed-by: Greg Kurz <groug@kaod.org>
> block/qcow2.h | 3 ++-
> block/qcow2-bitmap.c | 25 ++++++++++++++-----------
> block/qcow2.c | 6 ++----
> 3 files changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 6eac088f1c..3c64dcda33 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -972,7 +972,8 @@ void qcow2_cache_discard(Qcow2Cache *c, void *table);
> int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
> void **refcount_table,
> int64_t *refcount_table_size);
> -bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp);
> +bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, bool *header_updated,
> + Error **errp);
> bool qcow2_get_bitmap_info_list(BlockDriverState *bs,
> Qcow2BitmapInfoList **info_list, Error
> **errp);
> int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
> diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
> index 4f6138f544..500175f4e8 100644
> --- a/block/qcow2-bitmap.c
> +++ b/block/qcow2-bitmap.c
> @@ -962,25 +962,26 @@ static void set_readonly_helper(gpointer bitmap,
> gpointer value)
> bdrv_dirty_bitmap_set_readonly(bitmap, (bool)value);
> }
>
> -/* qcow2_load_dirty_bitmaps()
> - * Return value is a hint for caller: true means that the Qcow2 header was
> - * updated. (false doesn't mean that the header should be updated by the
> - * caller, it just means that updating was not needed or the image cannot be
> - * written to).
> - * On failure the function returns false.
> +/*
> + * Return true on success, false on failure. Anyway, if header_updated
> + * provided set it appropriately.
> */
> -bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp)
> +bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, bool *header_updated,
> + Error **errp)
> {
> BDRVQcow2State *s = bs->opaque;
> Qcow2BitmapList *bm_list;
> Qcow2Bitmap *bm;
> GSList *created_dirty_bitmaps = NULL;
> - bool header_updated = false;
> bool needs_update = false;
>
> + if (header_updated) {
> + *header_updated = false;
> + }
> +
> if (s->nb_bitmaps == 0) {
> /* No bitmaps - nothing to do */
> - return false;
> + return true;
> }
>
> bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
> @@ -1036,7 +1037,9 @@ bool qcow2_load_dirty_bitmaps(BlockDriverState *bs,
> Error **errp)
> error_setg_errno(errp, -ret, "Can't update bitmap directory");
> goto fail;
> }
> - header_updated = true;
> + if (header_updated) {
> + *header_updated = true;
> + }
> }
>
> if (!can_write(bs)) {
> @@ -1047,7 +1050,7 @@ bool qcow2_load_dirty_bitmaps(BlockDriverState *bs,
> Error **errp)
> g_slist_free(created_dirty_bitmaps);
> bitmap_list_free(bm_list);
>
> - return header_updated;
> + return true;
>
> fail:
> g_slist_foreach(created_dirty_bitmaps, release_dirty_bitmap_helper, bs);
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 8c89c98978..c4b86df7c0 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1297,7 +1297,6 @@ static int coroutine_fn qcow2_do_open(BlockDriverState
> *bs, QDict *options,
> unsigned int len, i;
> int ret = 0;
> QCowHeader header;
> - Error *local_err = NULL;
> uint64_t ext_end;
> uint64_t l1_vm_state_index;
> bool update_header = false;
> @@ -1785,9 +1784,8 @@ static int coroutine_fn qcow2_do_open(BlockDriverState
> *bs, QDict *options,
>
> if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) {
> /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */
> - bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err);
> - if (local_err != NULL) {
> - error_propagate(errp, local_err);
> + bool header_updated;
> + if (!qcow2_load_dirty_bitmaps(bs, &header_updated, errp)) {
> ret = -EINVAL;
> goto fail;
> }
- Re: [PATCH v2 12/13] block/qcow2: simplify qcow2_co_invalidate_cache(), (continued)
[PATCH v2 08/13] block/qcow2: qcow2_get_specific_info(): drop error propagation, Vladimir Sementsov-Ogievskiy, 2020/09/17
[PATCH v2 09/13] block/qcow2-bitmap: improve qcow2_load_dirty_bitmaps() interface, Vladimir Sementsov-Ogievskiy, 2020/09/17
[PATCH v2 13/13] block/qed: bdrv_qed_do_open: deal with errp, Vladimir Sementsov-Ogievskiy, 2020/09/17
Re: [PATCH v2 00/13] block: deal with errp: part I, no-reply, 2020/09/17