bcachefs: Don't run bch2_delete_dead_snapshots() unnecessarily

Be a bit more careful about when bch2_delete_dead_snapshots needs to
run: it only needs to run synchronously if we're running fsck, and it
only needs to run at all if we have snapshot nodes to delete or if fsck
has noticed that it needs to run.

Also:
  Rename BCH_FS_HAVE_DELETED_SNAPSHOTS -> BCH_FS_NEED_DELETE_DEAD_SNAPSHOTS

  Kill bch2_delete_dead_snapshots_hook(), move functionality to
  bch2_mark_snapshot()

  Factor out bch2_check_snapshot_needs_deletion(), to explicitly check
  if we need to be running snapshot deletion.

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

1 files changed, 2 insertions, 17 deletions

diff --git a/fs/bcachefs/subvolume.c b/fs/bcachefs/subvolume.c
index caf2dd7dafff..73ba22c219a1 100644
--- a/fs/bcachefs/subvolume.c
+++ b/fs/bcachefs/subvolume.c
@@ -230,7 +230,6 @@ static int __bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
 {
 	struct btree_iter iter;
 	struct bkey_s_c_subvolume subvol;
-	struct btree_trans_commit_hook *h;
 	u32 snapid;
 	int ret = 0;
 
@@ -246,22 +245,8 @@ static int __bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
 
 	snapid = le32_to_cpu(subvol.v->snapshot);
 
-	ret = bch2_btree_delete_at(trans, &iter, 0);
-	if (ret)
-		goto err;
-
-	ret = bch2_snapshot_node_set_deleted(trans, snapid);
-	if (ret)
-		goto err;
-
-	h = bch2_trans_kmalloc(trans, sizeof(*h));
-	ret = PTR_ERR_OR_ZERO(h);
-	if (ret)
-		goto err;
-
-	h->fn = bch2_delete_dead_snapshots_hook;
-	bch2_trans_commit_hook(trans, h);
-err:
+	ret =   bch2_btree_delete_at(trans, &iter, 0) ?:
+		bch2_snapshot_node_set_deleted(trans, snapid);
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
 }