Re: [PATCH 18/27] nilfs2: pathname operations

["Pekka Enberg" <penberg@cs.helsinki.fi>]

Hi Ryusuke,

On Sun, Sep 14, 2008 at 10:08 PM, Ryusuke Konishi
<konishi.ryusuke@lab.ntt.co.jp> wrote:
> This adds pathname operations, most of which comes from the ext2 file
> system.
>
> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
> +/*
> + * By the time this is called, we already have created
> + * the directory cache entry for the new file, but it
> + * is so far negative - it has no inode.
> + *
> + * If the create succeeds, we fill in the inode information
> + * with d_instantiate().
> + */
> +static int nilfs_create(struct inode *dir, struct dentry *dentry, int mode,
> +                       struct nameidata *nd)
> +{
> +       struct inode *inode;
> +       struct nilfs_transaction_info ti;
> +       int err, err2;
> +
> +       err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
> +       if (err)
> +               return err;
> +       inode = nilfs_new_inode(dir, mode);
> +       err = PTR_ERR(inode);
> +       if (!IS_ERR(inode)) {
> +               inode->i_op = &nilfs_file_inode_operations;
> +               inode->i_fop = &nilfs_file_operations;
> +               inode->i_mapping->a_ops = &nilfs_aops;
> +               mark_inode_dirty(inode);
> +               err = nilfs_add_nondir(dentry, inode);
> +       }
> +       err2 = nilfs_transaction_end(dir->i_sb, !err);

OK, I don't understand this. The only way nilfs_transaction_end() can
fail is if we have NILFS_TI_SYNC set and we fail to construct the
segment. But why do we want to construct a segment if we don't commit?

I guess what I'm asking is why don't we have a separate
nilfs_transaction_abort() function that can't fail for the erroneous
case to avoid this double error value tracking thing?

                      Pekka