Possible to speedup chownr?

[Ponnuvel Palaniyappan]

I wonder if `chownr` function (recursive chown) can be improved.

It calls `os.path.lexists` and `os.path.exists` for *every* file. The relevant source code from https://github.com/juju/charm-helpers/blob/master/charmhelpers/core/host.py#L927:

    for root, dirs, files in os.walk(path, followlinks=follow_links):
        for name in dirs + files:
            full = os.path.join(root, name)
            broken_symlink = os.path.lexists(full) and not os.path.exists(full)
            if not broken_symlink:
                chown(full, uid, gid)

I think the purpose of the extra check (not broken symlink) is to avoid calling chown on broken symlinks. Would rewriting this part to:

    for root, dirs, files in os.walk(path, followlinks=follow_links):
        for name in dirs + files:
            full = os.path.join(root, name)
            try:
                chown(full, uid, gid)
            except FileNotFoundError:
                pass

do the equivalent functionality? This would avoid nearly 2 system calls for every file.

Ordinarily, these "extra" system calls wouldn't be an issue for a directory with few files. But in case of ceph-osd charm where there can be a massive number of files, this is noticeable (few mins to hours - depending on the number of files).

[Ponnuvel Palaniyappan (pponnuvel)]

Github fix proposal: https://github.com/juju/charm-helpers/pull/516

[Ponnuvel Palaniyappan (pponnuvel)]

Closed the previous PR noted in #1 and new one is at https://github.com/juju/charm-helpers/pull/527 after addressing review comments.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Ponnuvel Palaniyappan (<email address hidden>) on branch: master
Review: https://review.opendev.org/759956

[Ponnuvel Palaniyappan (pponnuvel)]

https://review.opendev.org/c/openstack/charm-ceph-osd/+/762523 has been merged.