[PATCH 13/15] Add ngnfs_dir_rename() and very basic debugfs command

[Valerie Aurora]

On Wed, Mar 12, 2025 at 3:34 PM Valerie Aurora <val at versity.com> wrote:
>
> This has a known bug where after around 600 renames it returns a
> spurious ENOENT.

Hurray, I found this pesky bug when I made the same mistake writing xattrs:

> +int ngnfs_dir_rename(struct ngnfs_fs_info *nfi, struct ngnfs_inode_ino_gen *src_dir_ig,
> +                    char *src_name, size_t src_name_len, struct ngnfs_inode_ino_gen *dst_dir_ig,
> +                    char *dst_name, size_t dst_name_len)
> +{
> +       struct {
> +               struct ngnfs_transaction txn;
> +               struct ngnfs_inode_txn_ref src_dir, dst_dir, dst;
> +               struct dirent_args src_da, dst_da;
> +       } *op;
> +       int ret;
> +
> +       op = kmalloc(sizeof(*op), GFP_NOFS);
> +       if (!op) {
> +               ret = -ENOMEM;
> +               goto out;
> +       }
> +
> +       ngnfs_txn_init(&op->txn);
> +       init_dirent_args(&op->src_da, src_name, src_name_len, 0);
> +       init_dirent_args(&op->dst_da, dst_name, dst_name_len, 0);
> +
> +       do {
> +               ret = ngnfs_inode_get(nfi, &op->txn, NBF_READ, src_dir_ig, &op->src_dir)        ?:
> +                     check_ifmt(op->src_dir.ninode, S_IFDIR, -ENOTDIR)                         ?:
> +                     lookup_dirent(nfi, &op->txn, &op->src_dir, &op->src_da, false)            ?:
> +                     ngnfs_inode_get(nfi, &op->txn, NBF_READ, dst_dir_ig, &op->dst_dir)        ?:

These two NBF_READs should be NBF_WRITE, of course.

Valerie