rsync 3.1.1: --ignore-missing-args / --delete-missing args problem

[Georgy Fedorov]

Dear All,

We sometimes have to replicate large "live" filesystems with many ( 
sometimes millions, up to few hundred millions ) files on them. ( 
Copying actively used files is of course a bad idea, but it really helps 
to keep the delta small, so one final transfer can later save the day. )

The problem, as one may guess, is that some files may disappear during 
the process, so rsync finishes with an error code 23.
The good news is that since version 3.1.0 rsync has two options to 
address this problem: --ignore-missing-args and --delete-missing-args .

The bad news, however, is that even with any of these, when the file 
disappears, rsync handles the file transfer properly, but then tries to 
set times or attributes on these files nevertheless. That fails with 
errno 22 ( EINVAL ) and still leads to exit code 23, which is a bit of 
an annoyance.

I am currently trying to come up with a patch to address this issue, 
since I'd like to have exit code 0 for either of --ignore-missing-args 
or --delete-missing-args, when the files are, well, missing.

Probably it is not the right way to address this problem, but in the 
same vein as --ignore-missing-args are implemented, the patch can go as 
follows:
https://gist.github.com/anonymous/96ba8bf10f864a93fd9203f75c43ffe9 .

Basically we need to do two changes:

(1) in options.c, make sure that the "missing_args" value is transferred 
when set ; and
(2) in rsync.c, in the "missing_args" case, replace FERROR_XFER with 
something else, since apparently any log message with logcode 
FERROR_XFER sets the flag 'got_xfer_error' in log.c, and that finally 
leads to exit code RERR_PARTIAL (23), which is what we are trying to avoid.

I am currently testing this on fairly big datasets to see if there's 
something missing, and will write more when I see how it goes ( as I 
said, the data sets are fairly large ).

There shall be a better way to address that, but this is all I can do 
with a very shallow acquaintance with rsync source code. Nevertheless, 
it would be great if that could be fixed in the trunk one way or another )

Kind regards, George

-- 
George Fedorov
Senior Systems Specialist
Melbourne School of Engineering
The University of Melbourne, Victoria 3010, Australia
phone: *****
email: *****
http://www.eng.unimelb.edu.au/

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