bcachefs: bch2_snapshot_exists()

bch2_snapshot_equiv() is going away; convert users that just wanted to
know if the snapshot exists to something better

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

4 files changed, 21 insertions, 4 deletions

diff --git a/fs/bcachefs/data_update.c b/fs/bcachefs/data_update.c
index 31b2aeb0c6e6..585214931e05 100644
--- a/fs/bcachefs/data_update.c
+++ b/fs/bcachefs/data_update.c
@@ -620,7 +620,7 @@ int bch2_data_update_init(struct btree_trans *trans,
 	 * and we have to check for this because we go rw before repairing the
 	 * snapshots table - just skip it, we can move it later.
 	 */
-	if (unlikely(k.k->p.snapshot && !bch2_snapshot_equiv(c, k.k->p.snapshot)))
+	if (unlikely(k.k->p.snapshot && !bch2_snapshot_exists(c, k.k->p.snapshot)))
 		return -BCH_ERR_data_update_done;
 
 	if (!bkey_get_dev_refs(c, k))
diff --git a/fs/bcachefs/snapshot.c b/fs/bcachefs/snapshot.c
index f65f7b191d31..ac664888847f 100644
--- a/fs/bcachefs/snapshot.c
+++ b/fs/bcachefs/snapshot.c
@@ -318,6 +318,7 @@ static int __bch2_mark_snapshot(struct btree_trans *trans,
 	if (new.k->type == KEY_TYPE_snapshot) {
 		struct bkey_s_c_snapshot s = bkey_s_c_to_snapshot(new);
 
+		t->live		= true;
 		t->parent	= le32_to_cpu(s.v->parent);
 		t->children[0]	= le32_to_cpu(s.v->children[0]);
 		t->children[1]	= le32_to_cpu(s.v->children[1]);
@@ -914,7 +915,7 @@ static int check_snapshot_exists(struct btree_trans *trans, u32 id)
 {
 	struct bch_fs *c = trans->c;
 
-	if (bch2_snapshot_equiv(c, id))
+	if (bch2_snapshot_exists(c, id))
 		return 0;
 
 	/* Do we need to reconstruct the snapshot_tree entry as well? */
@@ -1062,7 +1063,7 @@ int bch2_reconstruct_snapshots(struct bch_fs *c)
 		snapshot_id_list_to_text(&buf, t);
 
 		darray_for_each(*t, id) {
-			if (fsck_err_on(!bch2_snapshot_equiv(c, *id),
+			if (fsck_err_on(!bch2_snapshot_exists(c, *id),
 					trans, snapshot_node_missing,
 					"snapshot node %u from tree %s missing, recreate?", *id, buf.buf)) {
 				if (t->nr > 1) {
@@ -1095,7 +1096,7 @@ int bch2_check_key_has_snapshot(struct btree_trans *trans,
 	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
-	if (fsck_err_on(!bch2_snapshot_equiv(c, k.k->p.snapshot),
+	if (fsck_err_on(!bch2_snapshot_exists(c, k.k->p.snapshot),
 			trans, bkey_in_missing_snapshot,
 			"key in missing snapshot %s, delete?",
 			(bch2_btree_id_to_text(&buf, iter->btree_id),
diff --git a/fs/bcachefs/snapshot.h b/fs/bcachefs/snapshot.h
index ae23d45fad66..3ff0ffa774f5 100644
--- a/fs/bcachefs/snapshot.h
+++ b/fs/bcachefs/snapshot.h
@@ -119,6 +119,21 @@ static inline u32 bch2_snapshot_root(struct bch_fs *c, u32 id)
 	return id;
 }
 
+static inline bool __bch2_snapshot_exists(struct bch_fs *c, u32 id)
+{
+	const struct snapshot_t *s = snapshot_t(c, id);
+	return s ? s->live : 0;
+}
+
+static inline bool bch2_snapshot_exists(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	bool ret = __bch2_snapshot_exists(c, id);
+	rcu_read_unlock();
+
+	return ret;
+}
+
 static inline u32 __bch2_snapshot_equiv(struct bch_fs *c, u32 id)
 {
 	const struct snapshot_t *s = snapshot_t(c, id);
diff --git a/fs/bcachefs/subvolume_types.h b/fs/bcachefs/subvolume_types.h
index f2ec4277c2a5..8a7f7e87c381 100644
--- a/fs/bcachefs/subvolume_types.h
+++ b/fs/bcachefs/subvolume_types.h
@@ -9,6 +9,7 @@ typedef DARRAY(u32) snapshot_id_list;
 #define IS_ANCESTOR_BITMAP	128
 
 struct snapshot_t {
+	bool			live;
 	u32			parent;
 	u32			skip[3];
 	u32			depth;