Re: [PATCH 07/17] vfs: Introduce new helpers for syncing after writing to O_SYNC file or IS_SYNC inode

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

> +int generic_write_sync(struct file *file, loff_t pos, loff_t count)
> +{
> +     if (!(file->f_flags & O_SYNC) && !IS_SYNC(file->f_mapping->host))
> +             return 0;
> +     return generic_sync_file(file, file->f_path.dentry, pos,
> +                              pos + count - 1,
> +                              SYNC_SUBMIT_DATA | SYNC_WAIT_DATA);
> +}
> +EXPORT_SYMBOL(generic_write_sync);

>  
> +/* Flags for generic_sync_file */
> +#define SYNC_INODE           1
> +#define SYNC_SUBMIT_DATA     2
> +#define SYNC_WAIT_DATA               4

When I think about this more I really hate the latter two flags.
There's really no reason to just do only either the submit or wait.
I'd say kill the flags for now and just implement generic_write_sync
as:

int generic_write_sync(struct file *file, loff_t pos, loff_t count)
{
        if (!(file->f_flags & O_SYNC) && !IS_SYNC(file->f_mapping->host))
                return 0;
        return vfs_fsync_range(file, file->f_path.dentry, pos,
                               pos + count - 1, 1);
}

and we can look into replacing the datasync flag with something more
meaningfull later through the whole fsync stack.