[PATCH] bcachefs: Fix evacuate_bucket tracepoint

[Kent Overstreet]

86a494c8eef9 ("bcachefs: Kill bch2_get_next_backpointer()") dropped some
things the tracepoint emitted because bch2_evacuate_bucket() no longer
looks at the alloc key - but we did want at least some of that.

We still no longer look at the alloc key so we can't report on the
fragmentation number, but that's a direct function of dirty_sectors and
a copygc concern anyways - copygc should get its own tracepoint that
includes information from the fragmentation LRU.

But we can report on the number of sectors we moved and the bucket size.

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>

diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c
index a98a0893a03b..07064872a697 100644
--- a/fs/bcachefs/move.c
+++ b/fs/bcachefs/move.c
@@ -674,8 +674,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 	struct bkey_buf sk;
 	struct bkey_s_c k;
 	struct data_update_opts data_opts;
-	unsigned dirty_sectors = 0, bucket_size = 0;
-	u64 fragmentation = 0;
+	unsigned sectors_moved = 0;
 	struct bkey_buf last_flushed;
 	int ret = 0;
 
@@ -750,15 +749,18 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 			data_opts.target	= io_opts.background_target;
 			data_opts.rewrite_ptrs = 0;
 
-			unsigned i = 0;
-			bkey_for_each_ptr(bch2_bkey_ptrs_c(k), ptr) {
-				if (ptr->dev == bucket.inode) {
-					data_opts.rewrite_ptrs |= 1U << i;
-					if (ptr->cached) {
+			unsigned i = 0, sectors = 0;
+			const union bch_extent_entry *entry;
+			struct extent_ptr_decoded p;
+			bkey_for_each_ptr_decode(k.k, bch2_bkey_ptrs_c(k), p, entry) {
+				if (p.ptr.dev == bucket.inode) {
+					if (p.ptr.cached) {
 						bch2_trans_iter_exit(trans, &iter);
 						goto next;
 					}
+					data_opts.rewrite_ptrs |= 1U << i;
 				}
+					sectors = ptr_disk_sectors(k.k->size, p);
 				i++;
 			}
 
@@ -777,7 +779,8 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 				goto err;
 
 			if (ctxt->stats)
-				atomic64_add(k.k->size, &ctxt->stats->sectors_seen);
+				atomic64_add(sectors, &ctxt->stats->sectors_seen);
+			sectors_moved += sectors;
 		} else {
 			struct btree *b;
 
@@ -808,12 +811,13 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 				atomic64_add(sectors, &ctxt->stats->sectors_seen);
 				atomic64_add(sectors, &ctxt->stats->sectors_moved);
 			}
+			sectors_moved += btree_sectors(c);
 		}
 next:
 		bch2_btree_iter_advance(&bp_iter);
 	}
 
-	trace_evacuate_bucket(c, &bucket, dirty_sectors, bucket_size, fragmentation, ret);
+	trace_evacuate_bucket(c, &bucket, sectors_moved, ca->mi.bucket_size, ret);
 err:
 	bch2_trans_iter_exit(trans, &bp_iter);
 	bch2_dev_put(ca);
diff --git a/fs/bcachefs/trace.h b/fs/bcachefs/trace.h
index 5597b9d6297f..2d5932d2881e 100644
--- a/fs/bcachefs/trace.h
+++ b/fs/bcachefs/trace.h
@@ -848,8 +848,8 @@ TRACE_EVENT(move_data,
 TRACE_EVENT(evacuate_bucket,
 	TP_PROTO(struct bch_fs *c, struct bpos *bucket,
 		 unsigned sectors, unsigned bucket_size,
-		 u64 fragmentation, int ret),
-	TP_ARGS(c, bucket, sectors, bucket_size, fragmentation, ret),
+		 int ret),
+	TP_ARGS(c, bucket, sectors, bucket_size, ret),
 
 	TP_STRUCT__entry(
 		__field(dev_t,		dev		)
@@ -857,7 +857,6 @@ TRACE_EVENT(evacuate_bucket,
 		__field(u64,		bucket		)
 		__field(u32,		sectors		)
 		__field(u32,		bucket_size	)
-		__field(u64,		fragmentation	)
 		__field(int,		ret		)
 	),
 
@@ -867,15 +866,14 @@ TRACE_EVENT(evacuate_bucket,
 		__entry->bucket			= bucket->offset;
 		__entry->sectors		= sectors;
 		__entry->bucket_size		= bucket_size;
-		__entry->fragmentation		= fragmentation;
 		__entry->ret			= ret;
 	),
 
-	TP_printk("%d,%d %llu:%llu sectors %u/%u fragmentation %llu ret %i",
+	TP_printk("%d,%d %llu:%llu sectors %u/%u ret %i",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->member, __entry->bucket,
 		  __entry->sectors, __entry->bucket_size,
-		  __entry->fragmentation, __entry->ret)
+		  __entry->ret)
 );
 
 TRACE_EVENT(copygc,