bcachefs: Clear BCH_FEATURE_extents_above_btree_updates on clean shutdown

This is needed so that users can roll back to before "d9bb516b2d
bcachefs: Move extent overwrite handling out of core btree code", which
it appears may still be buggy.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/recovery.c

@@ -805,8 +805,6 @@ int bch2_fs_recovery(struct bch_fs *c)
 		goto err;
 	}
 
-	c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_extents_above_btree_updates;
-
 	ret = journal_replay_early(c, clean, &journal_entries);
 	if (ret)
 		goto err;

fs/bcachefs/super-io.c

@@ -956,6 +956,7 @@ int bch2_fs_mark_dirty(struct bch_fs *c)
 	mutex_lock(&c->sb_lock);
 	SET_BCH_SB_CLEAN(c->disk_sb.sb, false);
 	c->disk_sb.sb->compat[0] &= ~(1ULL << BCH_COMPAT_FEAT_ALLOC_METADATA);
+	c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_extents_above_btree_updates;
 	ret = bch2_write_super(c);
 	mutex_unlock(&c->sb_lock);
 
@@ -1087,6 +1088,7 @@ void bch2_fs_mark_clean(struct bch_fs *c)
 
 	c->disk_sb.sb->compat[0] |= 1ULL << BCH_COMPAT_FEAT_ALLOC_INFO;
 	c->disk_sb.sb->compat[0] |= 1ULL << BCH_COMPAT_FEAT_ALLOC_METADATA;
+	c->disk_sb.sb->features[0] &= ~(1ULL << BCH_FEATURE_extents_above_btree_updates);
 
 	u64s = sizeof(*sb_clean) / sizeof(u64) + c->journal.entry_u64s_reserved;