| Message ID | 20180122220806.22154-12-mreitz@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 01/22 23:08, Max Reitz wrote: > This new function allows to look for a consecutively dirty area in a > dirty bitmap. > > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > include/block/dirty-bitmap.h | 2 ++ > block/dirty-bitmap.c | 51 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 53 insertions(+) > > diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h > index a591c27213..35f3ccc44c 100644 > --- a/include/block/dirty-bitmap.h > +++ b/include/block/dirty-bitmap.h > @@ -79,6 +79,8 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, > void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, > int64_t offset, int64_t bytes); > int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter); > +bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset, > + uint64_t *offset, int *bytes); > void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t offset); > int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap); > int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap); > diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c > index 50564fa1e2..484b5dda43 100644 > --- a/block/dirty-bitmap.c > +++ b/block/dirty-bitmap.c > @@ -501,6 +501,57 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter) > return hbitmap_iter_next(&iter->hbi, true); > } > > +/** > + * Return the next consecutively dirty area in the dirty bitmap > + * belonging to the given iterator @iter. > + * > + * @max_offset: Maximum value that may be returned for > + * *offset + *bytes > + * @offset: Will contain the start offset of the next dirty area > + * @bytes: Will contain the length of the next dirty area > + * > + * Returns: True if a dirty area could be found before max_offset > + * (which means that *offset and *bytes then contain valid > + * values), false otherwise. Also document the change to the iter cursor depending on the return value? Fam
On 2018-02-27 10:06, Fam Zheng wrote: > On Mon, 01/22 23:08, Max Reitz wrote: >> This new function allows to look for a consecutively dirty area in a >> dirty bitmap. >> >> Signed-off-by: Max Reitz <mreitz@redhat.com> >> --- >> include/block/dirty-bitmap.h | 2 ++ >> block/dirty-bitmap.c | 51 ++++++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 53 insertions(+) >> >> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h >> index a591c27213..35f3ccc44c 100644 >> --- a/include/block/dirty-bitmap.h >> +++ b/include/block/dirty-bitmap.h >> @@ -79,6 +79,8 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, >> void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, >> int64_t offset, int64_t bytes); >> int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter); >> +bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset, >> + uint64_t *offset, int *bytes); >> void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t offset); >> int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap); >> int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap); >> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c >> index 50564fa1e2..484b5dda43 100644 >> --- a/block/dirty-bitmap.c >> +++ b/block/dirty-bitmap.c >> @@ -501,6 +501,57 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter) >> return hbitmap_iter_next(&iter->hbi, true); >> } >> >> +/** >> + * Return the next consecutively dirty area in the dirty bitmap >> + * belonging to the given iterator @iter. >> + * >> + * @max_offset: Maximum value that may be returned for >> + * *offset + *bytes >> + * @offset: Will contain the start offset of the next dirty area >> + * @bytes: Will contain the length of the next dirty area >> + * >> + * Returns: True if a dirty area could be found before max_offset >> + * (which means that *offset and *bytes then contain valid >> + * values), false otherwise. > > Also document the change to the iter cursor depending on the return value? Good point, since it may be unexpected that it isn't advanced if max_offset would be exceeded. Max
diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h index a591c27213..35f3ccc44c 100644 --- a/include/block/dirty-bitmap.h +++ b/include/block/dirty-bitmap.h @@ -79,6 +79,8 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, int64_t offset, int64_t bytes); int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter); +bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset, + uint64_t *offset, int *bytes); void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t offset); int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap); int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap); diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index 50564fa1e2..484b5dda43 100644 --- a/block/dirty-bitmap.c +++ b/block/dirty-bitmap.c @@ -501,6 +501,57 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter) return hbitmap_iter_next(&iter->hbi, true); } +/** + * Return the next consecutively dirty area in the dirty bitmap + * belonging to the given iterator @iter. + * + * @max_offset: Maximum value that may be returned for + * *offset + *bytes + * @offset: Will contain the start offset of the next dirty area + * @bytes: Will contain the length of the next dirty area + * + * Returns: True if a dirty area could be found before max_offset + * (which means that *offset and *bytes then contain valid + * values), false otherwise. + */ +bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset, + uint64_t *offset, int *bytes) +{ + uint32_t granularity = bdrv_dirty_bitmap_granularity(iter->bitmap); + uint64_t gran_max_offset; + int64_t ret; + int size; + + if (max_offset == iter->bitmap->size) { + /* If max_offset points to the image end, round it up by the + * bitmap granularity */ + gran_max_offset = ROUND_UP(max_offset, granularity); + } else { + gran_max_offset = max_offset; + } + + ret = hbitmap_iter_next(&iter->hbi, false); + if (ret < 0 || ret + granularity > gran_max_offset) { + return false; + } + + *offset = ret; + size = 0; + + assert(granularity <= INT_MAX); + + do { + /* Advance iterator */ + ret = hbitmap_iter_next(&iter->hbi, true); + size += granularity; + } while (ret + granularity <= gran_max_offset && + hbitmap_iter_next(&iter->hbi, false) == ret + granularity && + size <= INT_MAX - granularity); + + *bytes = MIN(size, max_offset - *offset); + return true; +} + /* Called within bdrv_dirty_bitmap_lock..unlock */ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, int64_t offset, int64_t bytes)
This new function allows to look for a consecutively dirty area in a dirty bitmap. Signed-off-by: Max Reitz <mreitz@redhat.com> --- include/block/dirty-bitmap.h | 2 ++ block/dirty-bitmap.c | 51 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+)