[bcachefs:bcachefs-testing 35/35] fs/bcachefs/alloc/foreground.c:560:2: warning: label followed by a declaration is a C23 extension

[kernel test robot <lkp@intel.com>]

tree:   https://evilpiepirate.org/git/bcachefs.git bcachefs-testing
head:   db7e4548979f797675fe7214f4745be25d16c455
commit: 3dd173bb8d58e827ecf6cdd31e81dc52f8d75110 [35/35] bcachefs: alloc: filter spurious freelist_wait wakes on the waiter side
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20260424/202604241231.XHlNZ0fg-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260424/202604241231.XHlNZ0fg-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202604241231.XHlNZ0fg-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/bcachefs/alloc/foreground.c:560:2: warning: label followed by a declaration is a C23 extension [-Wc23-extensions]
     560 |         u32 wake_counter_snapshot = atomic_read(&ca->alloc_wake_counter);
         |         ^
   1 warning generated.


vim +560 fs/bcachefs/alloc/foreground.c

   540	
   541	/**
   542	 * bch2_bucket_alloc_trans - allocate a single bucket from a specific device
   543	 * @trans:	transaction object
   544	 * @req:	state for the entire allocation
   545	 *
   546	 * Returns:	an open_bucket on success, or an ERR_PTR() on failure.
   547	 */
   548	static struct open_bucket *bch2_bucket_alloc_trans(struct btree_trans *trans,
   549							   struct alloc_request *req)
   550	{
   551		struct bch_fs *c = trans->c;
   552		struct bch_dev *ca = req->ca;
   553		struct open_bucket *ob = NULL;
   554		bool freespace = READ_ONCE(ca->mi.freespace_initialized);
   555		bool waiting = false;
   556	
   557		req->btree_bitmap = req->data_type == BCH_DATA_btree;
   558		memset(&req->counters, 0, sizeof(req->counters));
   559	again:
 > 560		u32 wake_counter_snapshot = atomic_read(&ca->alloc_wake_counter);
   561		bch2_dev_usage_read_fast(ca, &req->usage);
   562		u64 avail = __dev_buckets_free(ca, req->usage, req->watermark);
   563	
   564		if (req->usage.buckets[BCH_DATA_need_discard] >
   565		    min(avail, ca->mi.nbuckets >> 7))
   566			bch2_do_discards_async(c);
   567	
   568		if (req->usage.buckets[BCH_DATA_need_gc_gens] > avail)
   569			bch2_gc_gens_async(c);
   570	
   571		if (should_invalidate_buckets(ca, req->usage))
   572			bch2_dev_do_invalidates(ca);
   573	
   574		if (!avail) {
   575			if (req->watermark > BCH_WATERMARK_normal &&
   576			    c->recovery.pass_done < BCH_RECOVERY_PASS_check_allocations)
   577				goto alloc;
   578	
   579			if (bch2_copygc_can_make_progress(ca)) {
   580				req->copygc_can_make_progress = true;
   581				bch2_copygc_wakeup(c);
   582			}
   583	
   584			track_event_change(&c->times[BCH_TIME_blocked_allocate], true);
   585	
   586			if (req->cl &&
   587			    !(req->flags & BCH_WRITE_alloc_nowait) &&
   588			    !req->will_retry_target_devices &&
   589			    !req->will_retry_all_devices &&
   590			    !req->will_retry_set_devices) {
   591				if ((!req->copygc_can_make_progress ||
   592				     req->watermark == BCH_WATERMARK_copygc) &&
   593				    (req->nr_effective || (req->devs_have && req->devs_have->nr))) {
   594					ob = ERR_PTR(bch_err_throw(c, bucket_alloc_no_progress));
   595				} else if (!waiting) {
   596					closure_wait(&c->allocator.freelist_wait, req->cl);
   597					waiting = true;
   598					goto again;
   599				} else {
   600					ob = ERR_PTR(bch_err_throw(c, bucket_alloc_blocked));
   601				}
   602			} else {
   603				ob = ERR_PTR(bch_err_throw(c, freelist_empty));
   604			}
   605	
   606			goto err;
   607		}
   608	
   609		if (waiting)
   610			bch2_alloc_wake_dev(ca);
   611	alloc:
   612		ob = likely(freespace)
   613			? bch2_bucket_alloc_freelist(trans, req)
   614			: bch2_bucket_alloc_early(trans, req);
   615	
   616		if (!ob && req->btree_bitmap != BTREE_BITMAP_ANY) {
   617			req->btree_bitmap = BTREE_BITMAP_ANY;
   618			goto alloc;
   619		}
   620	
   621		if (!ob && freespace && c->recovery.pass_done < BCH_RECOVERY_PASS_check_alloc_info) {
   622			freespace = false;
   623			goto alloc;
   624		}
   625	err:
   626		if (!ob)
   627			ob = ERR_PTR(bch_err_throw(c, no_buckets_found));
   628	
   629		int ret = PTR_ERR_OR_ZERO(ob);
   630	
   631		if (!ret) {
   632			ob->data_type = req->data_type;
   633	
   634			event_inc_trace(c, bucket_alloc, buf,
   635				bucket_alloc_to_text(&buf, c, req, ob));
   636		} else if (bch2_err_matches(ret, BCH_ERR_open_buckets_empty) ||
   637			   bch2_err_matches(ret, BCH_ERR_open_bucket_alloc_blocked)) {
   638			event_inc_trace(c, open_bucket_alloc_fail, buf,
   639				bch2_fs_open_buckets_to_text(&buf, c));
   640		} else if (!bch2_err_matches(ret, BCH_ERR_transaction_restart) &&
   641			   !req->will_retry_target_devices &&
   642			   !req->will_retry_all_devices &&
   643			   !req->will_retry_set_devices)
   644			event_inc_trace(c, bucket_alloc_fail, buf,
   645				bucket_alloc_to_text(&buf, c, req, ob));
   646	
   647		alloc_trace_add(req, ca->dev_idx, ret, wake_counter_snapshot);
   648	
   649		return ob;
   650	}
   651	

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