1 files changed, 53 insertions, 61 deletions

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index cc856150a948..ef02c9bb0354 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -5,6 +5,7 @@
 #include "backpointers.h"
 #include "btree_cache.h"
 #include "btree_update.h"
+#include "btree_update_interior.h"
 #include "btree_write_buffer.h"
 #include "error.h"
 
@@ -37,25 +38,26 @@ static bool extent_matches_bp(struct bch_fs *c,
 	return false;
 }
 
-int bch2_backpointer_invalid(const struct bch_fs *c, struct bkey_s_c k,
+int bch2_backpointer_invalid(struct bch_fs *c, struct bkey_s_c k,
 			     enum bkey_invalid_flags flags,
 			     struct printbuf *err)
 {
 	struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
 	struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);
+	int ret = 0;
 
-	if (!bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset))) {
-		prt_str(err, "backpointer at wrong pos");
-		return -BCH_ERR_invalid_bkey;
-	}
-
-	return 0;
+	bkey_fsck_err_on(!bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset)),
+			 c, err,
+			 backpointer_pos_wrong,
+			 "backpointer at wrong pos");
+fsck_err:
+	return ret;
 }
 
 void bch2_backpointer_to_text(struct printbuf *out, const struct bch_backpointer *bp)
 {
 	prt_printf(out, "btree=%s l=%u offset=%llu:%u len=%u pos=",
-	       bch2_btree_ids[bp->btree_id],
+	       bch2_btree_id_str(bp->btree_id),
 	       bp->level,
 	       (u64) (bp->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT),
 	       (u32) bp->bucket_offset & ~(~0U << MAX_EXTENT_COMPRESS_RATIO_SHIFT),
@@ -76,7 +78,7 @@ void bch2_backpointer_swab(struct bkey_s k)
 {
 	struct bkey_s_backpointer bp = bkey_s_to_backpointer(k);
 
-	bp.v->bucket_offset	= swab32(bp.v->bucket_offset);
+	bp.v->bucket_offset	= swab40(bp.v->bucket_offset);
 	bp.v->bucket_len	= swab32(bp.v->bucket_len);
 	bch2_bpos_swab(&bp.v->pos);
 }
@@ -219,18 +221,22 @@ out:
 static void backpointer_not_found(struct btree_trans *trans,
 				  struct bpos bp_pos,
 				  struct bch_backpointer bp,
-				  struct bkey_s_c k,
-				  const char *thing_it_points_to)
+				  struct bkey_s_c k)
 {
 	struct bch_fs *c = trans->c;
 	struct printbuf buf = PRINTBUF;
 	struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
 
+	/*
+	 * If we're using the btree write buffer, the backpointer we were
+	 * looking at may have already been deleted - failure to find what it
+	 * pointed to is not an error:
+	 */
 	if (likely(!bch2_backpointers_no_use_write_buffer))
 		return;
 
 	prt_printf(&buf, "backpointer doesn't match %s it points to:\n  ",
-		   thing_it_points_to);
+		   bp.level ? "btree node" : "extent");
 	prt_printf(&buf, "bucket: ");
 	bch2_bpos_to_text(&buf, bucket);
 	prt_printf(&buf, "\n  ");
@@ -256,56 +262,37 @@ struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 					 struct bch_backpointer bp,
 					 unsigned iter_flags)
 {
-	struct bch_fs *c = trans->c;
-	struct btree_root *r = bch2_btree_id_root(c, bp.btree_id);
-	struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
-	struct bkey_s_c k;
-
-	bch2_trans_node_iter_init(trans, iter,
-				  bp.btree_id,
-				  bp.pos,
-				  0,
-				  min(bp.level, r->level),
-				  iter_flags);
-	k = bch2_btree_iter_peek_slot(iter);
-	if (bkey_err(k)) {
-		bch2_trans_iter_exit(trans, iter);
-		return k;
-	}
-
-	if (bp.level == r->level + 1)
-		k = bkey_i_to_s_c(&r->key);
-
-	if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
-		return k;
-
-	bch2_trans_iter_exit(trans, iter);
+	if (likely(!bp.level)) {
+		struct bch_fs *c = trans->c;
+		struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
+		struct bkey_s_c k;
+
+		bch2_trans_node_iter_init(trans, iter,
+					  bp.btree_id,
+					  bp.pos,
+					  0, 0,
+					  iter_flags);
+		k = bch2_btree_iter_peek_slot(iter);
+		if (bkey_err(k)) {
+			bch2_trans_iter_exit(trans, iter);
+			return k;
+		}
 
-	if (unlikely(bch2_backpointers_no_use_write_buffer)) {
-		if (bp.level) {
-			struct btree *b;
+		if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
+			return k;
 
-			/*
-			 * If a backpointer for a btree node wasn't found, it may be
-			 * because it was overwritten by a new btree node that hasn't
-			 * been written out yet - backpointer_get_node() checks for
-			 * this:
-			 */
-			b = bch2_backpointer_get_node(trans, iter, bp_pos, bp);
-			if (!IS_ERR_OR_NULL(b))
-				return bkey_i_to_s_c(&b->key);
+		bch2_trans_iter_exit(trans, iter);
+		backpointer_not_found(trans, bp_pos, bp, k);
+		return bkey_s_c_null;
+	} else {
+		struct btree *b = bch2_backpointer_get_node(trans, iter, bp_pos, bp);
 
+		if (IS_ERR_OR_NULL(b)) {
 			bch2_trans_iter_exit(trans, iter);
-
-			if (IS_ERR(b))
-				return bkey_s_c_err(PTR_ERR(b));
-			return bkey_s_c_null;
+			return IS_ERR(b) ? bkey_s_c_err(PTR_ERR(b)) : bkey_s_c_null;
 		}
-
-		backpointer_not_found(trans, bp_pos, bp, k, "extent");
+		return bkey_i_to_s_c(&b->key);
 	}
-
-	return bkey_s_c_null;
 }
 
 struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
@@ -329,6 +316,8 @@ struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 	if (IS_ERR(b))
 		goto err;
 
+	BUG_ON(b->c.level != bp.level - 1);
+
 	if (b && extent_matches_bp(c, bp.btree_id, bp.level,
 				   bkey_i_to_s_c(&b->key),
 				   bucket, bp))
@@ -337,8 +326,7 @@ struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 	if (b && btree_node_will_make_reachable(b)) {
 		b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
 	} else {
-		backpointer_not_found(trans, bp_pos, bp,
-				      bkey_i_to_s_c(&b->key), "btree node");
+		backpointer_not_found(trans, bp_pos, bp, bkey_i_to_s_c(&b->key));
 		b = NULL;
 	}
 err:
@@ -356,6 +344,7 @@ static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_
 	int ret = 0;
 
 	if (fsck_err_on(!bch2_dev_exists2(c, k.k->p.inode), c,
+			backpointer_to_missing_device,
 			"backpointer for missing device:\n%s",
 			(bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
 		ret = bch2_btree_delete_at(trans, bp_iter, 0);
@@ -369,6 +358,7 @@ static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_
 		goto out;
 
 	if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4, c,
+			backpointer_to_missing_alloc,
 			"backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
 			alloc_iter.pos.inode, alloc_iter.pos.offset,
 			(bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
@@ -453,14 +443,14 @@ fsck_err:
 	return ret;
 missing:
 	prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
-	       bch2_btree_ids[bp.btree_id], bp.level);
+	       bch2_btree_id_str(bp.btree_id), bp.level);
 	bch2_bkey_val_to_text(&buf, c, orig_k);
 	prt_printf(&buf, "\nbp pos ");
 	bch2_bpos_to_text(&buf, bp_iter.pos);
 
 	if (c->sb.version_upgrade_complete < bcachefs_metadata_version_backpointers ||
 	    c->opts.reconstruct_alloc ||
-	    fsck_err(c, "%s", buf.buf))
+	    fsck_err(c, ptr_to_missing_backpointer, "%s", buf.buf))
 		ret = bch2_bucket_backpointer_mod(trans, bucket, bp, orig_k, true);
 
 	goto out;
@@ -793,7 +783,9 @@ static int check_one_backpointer(struct btree_trans *trans,
 	}
 
 	if (fsck_err_on(!k.k, c,
-			"backpointer for missing extent\n  %s",
+			backpointer_to_missing_ptr,
+			"backpointer for missing %s\n  %s",
+			bp.v->level ? "btree node" : "extent",
 			(bch2_bkey_val_to_text(&buf, c, bp.s_c), buf.buf))) {
 		ret = bch2_btree_delete_at_buffered(trans, BTREE_ID_backpointers, bp.k->p);
 		goto out;