bcachefs: check_extent(): don't use key_visible_in_snapshot()

This changes the main part of check_extents(), that checks the extent
against the corresponding inode, to not use key_visible_in_snapshot().

key_visible_in_snapshot() has to iterate over the list of ancestor
overwrites repeatedly calling bch2_snapshot_is_ancestor(), so this is a
significant performance improvement.

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

diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index 3a3d89bdf1c96692c55ec3a5fb8c1595e847ffa3..784e55166df26b1ffbc45201b4c36c8b9e6099c9 100644 (file)
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -471,28 +471,6 @@ static inline void snapshots_seen_init(struct snapshots_seen *s)
        memset(s, 0, sizeof(*s));
 }
 
-static int snapshots_seen_add(struct bch_fs *c, struct snapshots_seen *s, u32 id)
-{
-       struct snapshots_seen_entry *i, n = { id, id };
-       int ret;
-
-       darray_for_each(s->ids, i) {
-               if (n.equiv < i->equiv)
-                       break;
-
-               if (i->equiv == n.equiv) {
-                       bch_err(c, "%s(): adding duplicate snapshot", __func__);
-                       return -EINVAL;
-               }
-       }
-
-       ret = darray_insert_item(&s->ids, i - s->ids.data, n);
-       if (ret)
-               bch_err(c, "error reallocating snapshots_seen table (size %zu)",
-                       s->ids.size);
-       return ret;
-}
-
 static int snapshots_seen_update(struct bch_fs *c, struct snapshots_seen *s,
                                 enum btree_id btree_id, struct bpos pos)
 {
@@ -1391,10 +1369,14 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
        }
 
        /*
-        * Check inodes in reverse order, from oldest snapshots to newest, so
-        * that we emit the fewest number of whiteouts necessary:
+        * Check inodes in reverse order, from oldest snapshots to newest,
+        * starting from the inode that matches this extent's snapshot. If we
+        * didn't have one, iterate over all inodes:
         */
-       for (i = inode->inodes.data + inode->inodes.nr - 1;
+       if (!i)
+               i = inode->inodes.data + inode->inodes.nr - 1;
+
+       for (;
             inode->inodes.data && i >= inode->inodes.data;
             --i) {
                if (i->snapshot > equiv.snapshot ||
@@ -1419,20 +1401,15 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
                                if (ret)
                                        goto err;
 
-                               if (i->snapshot != equiv.snapshot) {
-                                       ret = snapshots_seen_add(c, s, i->snapshot);
-                                       if (ret)
-                                               goto err;
-                               }
-
                                iter->k.type = KEY_TYPE_whiteout;
                        }
+
+                       if (bkey_extent_is_allocation(k.k))
+                               i->count += k.k->size;
                }
-       }
 
-       if (bkey_extent_is_allocation(k.k))
-               for_each_visible_inode(c, s, inode, equiv.snapshot, i)
-                       i->count += k.k->size;
+               i->seen_this_pos = true;
+       }
 out:
 err:
 fsck_err: