rsync fails to sync files

[Atte Peltomaki]

Hi,

I'm seeing a weird problem with rsync 2.6.9 protocol version 29 on
Debian Sarge. When copying a file from one location to another between
two Debian boxes, if destination includes a file with same size and
name, rsync fails to see that they are not exactly the same file.

The situation originates from copying a file to a place which is
periodically rsynced onwards, and the rsync coperation takes place before
the original file transfer to the rsync source is complete.

Example:

Source:

md5sum:
2ac4a4ad88da17f49d26c9e578ce5432  somefile.exe
sha1sum:
eaabb30b716e993be000b89208e2d9f63e78f052  somefile.exe
ls -l:
-rwxrw----  1 user group 109819105 Apr  2 10:48 somefile.exe*

Destination:

md5sum:
72c116866a75f859a19a150216768e52  somefile.exe
sha1sum:
33b7d91fc6bd2a5bff292258c7d6eeb7db0aec8a  somefile.exe
ls -l:
-rwxrw----  1 user group 109819105 2007-04-02 10:48 somefile.exe*

rsync is executed from the source with following flags:

-alvv --delete --exclude-from=file 

where 'file' includes three lines:
/upload
/upload/*
upload/

rsync itself says about somefile.exe: 

somefile.exe is uptodate

As you can see, md5sums and sha1sums reveal that the file is not the
same, even though timestamps and sizes match. 

What is the exact algorithm rsync uses to determien wether a file is up
to date or not? 

-- 
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 \   ______//     Atte Peltomäki - atte.peltomaki at f-secure.com
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