Does rsync need a --ignore-unreadable-files option?

[Allen Supynuk]

I work on software that archives gigabytes of files to multiple sites.

Occasionally one or two files have no read permissions:

% ls -l dir/foo
--w-------+ 1 abcserve myusers 11222 Jan 10 03:14

The error message is:
rsync: send_files failed to open "/dir/foo" (in xxx): Permission denied (13)

rsync error: some files/attrs were not transferred (see previous
errors) (code 23) at main.c(1518) [generator=3.0.9]

--

To make matters worse, the file is on a read-only snapshot mounted
through NFS. In any case root squash is in effect, so super-user is
out.

I fully realize that the correct answer is "fix the file permissions
and regenerate". Which is precisely what we do today. However,
regenerating takes several hours, so no one has access to the archives
until it is done.

The one work-around I have found is to redo the rsync with
--exclude='/dir/foo'. I am thinking about adding a facility to my
software that generates the rsync commands to allow adding options.

It strikes me though, that what I really want is an rsync option
'--ignore-files-with-no-read-perms'. This rightfully should be off by
default, but once you have a system up and running like we do, it says
"if we screw up the read permissions on an occasional file just keep
going". I would expect that '--itemize-changes' would make a note that
the file was not copied.

In my case, the files have always had no read access for anyone, and
are owned by id running rsync. That is, if the files *were* on a
writable volume, chmod.would fix it (but not --fake-super, nor any
combination of --no-perms and --chmod=ugo+r that I tried on /tmp on my
desktop). That is, there is no possibility of anyone other than
someone with root access to the file system making a copy of this
file. Having an option to ignore seems safe enough.

Ignoring return code 23 (Partial transfer due to error), similar to
the FAQ suggestion for code 24 (Partial transfer due to vanished
source files) seems much too risky. I only want to ignore the case of
the files being unreadable because they were explicitly denied read
permissions, not because of media failure or (my favorite vendor
response) "ionizing radiation".

Am I missing some obvious settings that can achieve this? An hour
spent googling, reading the rsync posts on Stack Overflow, and the
last 14 months of archives on this list found nothing.

Ps. If this does make sense I am volunteering to make the change.

-- 
Allen.Supynuk at gmail.com