bcachefs: Fix BTREE_ITER_FILTER_SNAPSHOTS on inodes btree

If we're in FILTER_SNAPSHOTS mode and we start scanning a range of the
keyspace where no keys are visible in the current snapshot, we have a
problem - we'll scan for a very long time before scanning terminates.

Awhile back, this was fixed for most cases with peek_upto() (and
assertions that enforce that it's being used).

But the fix missed the fact that the inodes btree is different - every
key offset is in a different snapshot tree, not just the inode field.

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

Author: Kent Overstreet

fs/bcachefs/btree_iter.c

@@ -2156,7 +2156,9 @@ struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *iter, struct bpos e
 		 * isn't monotonically increasing before FILTER_SNAPSHOTS, and
 		 * that's what we check against in extents mode:
 		 */
-		if (k.k->p.inode > end.inode)
+		if (unlikely(!(iter->flags & BTREE_ITER_IS_EXTENTS)
+			     ? bkey_gt(k.k->p, end)
+			     : k.k->p.inode > end.inode))
 			goto end;
 
 		if (iter->update_path &&