btrfs: remove duplicate name variable declarations

When running 'make W=2' there are a few reports where a variable of the
same name is declared in a nested block. In all the cases we can use the
one declared in the parent block, no problematic cases were found.
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -3507,7 +3507,6 @@ struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src)
 
 	for (int i = 0; i < num_folios; i++) {
 		struct folio *folio = new->folios[i];
-		int ret;
 
 		ret = attach_extent_buffer_folio(new, folio, NULL);
 		if (ret < 0) {
@@ -4589,8 +4588,7 @@ static void assert_eb_folio_uptodate(const struct extent_buffer *eb, int i)
 		return;
 
 	if (fs_info->nodesize < PAGE_SIZE) {
-		struct folio *folio = eb->folios[0];
-
+		folio = eb->folios[0];
 		ASSERT(i == 0);
 		if (WARN_ON(!btrfs_subpage_test_uptodate(fs_info, folio,
 							 eb->start, eb->len)))

fs/btrfs/inode.c

@@ -1617,10 +1617,8 @@ static noinline void submit_compressed_extents(struct btrfs_work *work, bool do_
 	u64 alloc_hint = 0;
 
 	if (do_free) {
-		struct async_chunk *async_chunk;
 		struct async_cow *async_cow;
 
-		async_chunk = container_of(work, struct async_chunk, work);
 		btrfs_add_delayed_iput(async_chunk->inode);
 		if (async_chunk->blkcg_css)
 			css_put(async_chunk->blkcg_css);