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nbd/server: use bdrv_dirty_bitmap_next_dirty_area 

Use bdrv_dirty_bitmap_next_dirty_area for bitmap_to_extents. Since
bdrv_dirty_bitmap_next_dirty_area is very accurate in its interface,
we'll never exceed requested region with last chunk. So, we don't need
dont_fragment, and bitmap_to_extents() interface becomes clean enough
to not require any comment.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20200205112041.6003-10-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2020-02-05 14:20:40 +03:00 committed by John Snow
parent 89cbc7e308
commit dacbb6eb8a
1 changed files with 19 additions and 40 deletions
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59
nbd/server.c
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@ -2068,57 +2068,36 @@ static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
}
/*
* Populate @ea from a dirty bitmap. Unless @dont_fragment, the
* final extent may exceed the original @length.
*/
/* Populate @ea from a dirty bitmap. */
static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
uint64_t offset, uint64_t length,
NBDExtentArray *ea, bool dont_fragment)
NBDExtentArray *es)
{
uint64_t begin = offset, end = offset;
uint64_t overall_end = offset + length;
BdrvDirtyBitmapIter *it;
bool dirty;
int64_t start, dirty_start, dirty_count;
int64_t end = offset + length;
bool full = false;
bdrv_dirty_bitmap_lock(bitmap);
it = bdrv_dirty_iter_new(bitmap);
dirty = bdrv_dirty_bitmap_get_locked(bitmap, offset);
while (begin < overall_end) {
bool next_dirty = !dirty;
if (dirty) {
end = bdrv_dirty_bitmap_next_zero(bitmap, begin, INT64_MAX);
} else {
bdrv_set_dirty_iter(it, begin);
end = bdrv_dirty_iter_next(it);
}
if (end == -1 || end - begin > UINT32_MAX) {
/* Cap to an aligned value < 4G beyond begin. */
end = MIN(bdrv_dirty_bitmap_size(bitmap),
begin + UINT32_MAX + 1 -
bdrv_dirty_bitmap_granularity(bitmap));
next_dirty = dirty;
}
if (dont_fragment && end > overall_end) {
end = overall_end;
}
if (nbd_extent_array_add(ea, end - begin,
dirty ? NBD_STATE_DIRTY : 0) < 0) {
for (start = offset;
bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX,
&dirty_start, &dirty_count);
start = dirty_start + dirty_count)
{
if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) ||
(nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0))
{
full = true;
break;
}
begin = end;
dirty = next_dirty;
}
bdrv_dirty_iter_free(it);
if (!full) {
/* last non dirty extent */
nbd_extent_array_add(es, end - start, 0);
}
bdrv_dirty_bitmap_unlock(bitmap);
assert(offset < end);
}
static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
@ -2129,7 +2108,7 @@ static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
bitmap_to_extents(bitmap, offset, length, ea, dont_fragment);
bitmap_to_extents(bitmap, offset, length, ea);
return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
}