[CentOS] Need help to fix bug in rsync

Wed Mar 25 13:49:24 UTC 2020
Simon Matter <simon.matter at invoca.ch>


I've discovered a bug in rsync which leads to increased CPU usage and
slower transfers in many situations.

When syncing with compression (-z), certain file types should not be
compressed during the transfer because they are already compressed. The
file types which are not to be compressed can be seen in the man page
section --skip-compress.

Unfortunately skipping the default file types doesn't work and all
transferred data is being compressed during the transfer. This is true for
all versions since 3.1.0.

Steps to Reproduce:
1. run 'rm -f Z ; rsync -azv alpha:z.gz Z'

Actual results, transferred data was compressed during the transfer:
sent 43 bytes  received 63,873 bytes  25,566.40 bytes/sec
total size is 628,952  speedup is 9.84

Expected results:
No compression should happen for .gz file.

Additional info:
Note that the source file 'z.gz' was an ascii text file to show clearly
that compression took place.

Please the following BZ for more info:

I tried to locate the bug in the code but failed. That said I'm not a C
developer and therefore need some help from someone who understands C
better than me. Any help is much appreciated!

Thanks and kind regards,