[PATCH AUTOSEL 5.15 09/18] btrfs: improve error message after failure to add delayed dir index item

[Sasha Levin]

From: Filipe Manana <fdmanana@xxxxxxxx>

[ Upstream commit 91bfe3104b8db0310f76f2dcb6aacef24c889366 ]

If we fail to add a delayed dir index item because there's already another
item with the same index number, we print an error message (and then BUG).
However that message isn't very helpful to debug anything because we don't
know what's the index number and what are the values of index counters in
the inode and its delayed inode (index_cnt fields of struct btrfs_inode
and struct btrfs_delayed_node).

So update the error message to include the index number and counters.

We actually had a recent case where this issue was hit by a syzbot report
(see the link below).

Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@xxxxxxxxxx/
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/btrfs/delayed-inode.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 1e08eb2b27f0c..429a571435a5b 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1388,9 +1388,10 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 	ret = __btrfs_add_delayed_insertion_item(delayed_node, delayed_item);
 	if (unlikely(ret)) {
 		btrfs_err(trans->fs_info,
-			  "err add delayed dir index item(name: %.*s) into the insertion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
-			  name_len, name, delayed_node->root->root_key.objectid,
-			  delayed_node->inode_id, ret);
+"error adding delayed dir index item, name: %.*s, index: %llu, root: %llu, dir: %llu, dir->index_cnt: %llu, delayed_node->index_cnt: %llu, error: %d",
+			  name_len, name, index, btrfs_root_id(delayed_node->root),
+			  delayed_node->inode_id, dir->index_cnt,
+			  delayed_node->index_cnt, ret);
 		BUG();
 	}
 	mutex_unlock(&delayed_node->mutex);
-- 
2.40.1