If the receiving side cannot hard-link symlinks and/or special files
(including devices) then we now properly handle incoming hard-linked
items (creating separate identical items).
I added a compatibility flag for protocol 31 that will let both sides
know if they should be using the xattr optimization that attempted to
avoid sending xattr info for hardlinked files. Since this optimization
was causing some issues, this compatibility flag will ensure that both
sides know if they should be trying to use the optimization or not.
Adding new-style compression that only compresses the literal data that
is sent over the wire and not also matching file data that was not sent.
This new-style compression is compatible with external zlib instances,
and will eventually become the default (once enough time has passed that
all servers support the --new-compress and --old-compress options).
NOTE: if you build rsync with an external zlib (i.e. if you specified
configure --with-included-zlib=no) you will ONLY get support for the
--new-compress option! A client will treat -z as uncompressed (with a
warning) and a server will exit with an error (unless -zz was used).
If the receiver gets a filename with a leading slash (w/o --relative)
and/or a filename with an embedded ".." dir in the path, it dies with
an error (rather than continuing). Those invalid paths should never
happen in reality, so just reject someone trying to pull a fast one.
If the receiver is running without --relative, it shouldn't be receiving
any filenames with a leading slash. To ensure that the sender doesn't
try to pull a fast one on us, we now make flist_sort_and_clean() strip a
leading slash even if --relative isn't specified.
I'm backing out the xattr optimization that was put in to try
to make xattr data sending more optimal on hard-linked files.
The code was causing hard-to-reproduce bugs, and it's better to
get things done fully & correctly over fully optimally.
