----- Original Message ----- > From: "Poornima Gurusiddaiah" <[email protected]> > To: "Gluster Devel" <[email protected]>, "Niels de Vos" > <[email protected]>, "Jeff Darcy" > <[email protected]>, "Raghavendra Talur" <[email protected]>, "Rajesh Joseph" > <[email protected]>, "Pranith Kumar > Karampuri" <[email protected]>, "Soumya Koduri" <[email protected]>, > "Raghavendra Gowdappa" > <[email protected]>, "Anoop Chirayath Manjiyil Sajan" <[email protected]> > Sent: Friday, May 13, 2016 3:18:51 PM > Subject: Usage of xdata to send anything on wire > > Hi, > > In the recent past, have seen multiple instances where we needed to send some > data along with the fop on wire. And we have been using the xdata for the > same. Eg: > 1. Add lease-id, transaction id to every fop. > 2. Send the xattrs to invalidate in xdata. > 3. Send the share flags during open. > > There were concerns raised around this for the below reasons: > 1. word-size and endianness > 2. security issues > 3. Backward compatibility issues i.e. old/new client and server combination.
Can you please elaborate on the above 3 points? A bit more verbose explanation of what and how the above factors cause problems will help. > > Initiating this mail to arrive at a conclusion, whether we can use xdata or > we need to find a different solution, if so what is the solution. > Your thoughts comments are appreciated. > > Solution 1: > To get rid of sending xdata on wire, one of the solution could be to have > protocol versioning in Gluster. With this we can modify xdr structures for > each release and get rid of xdata. But this will be huge work. > > Solution 2: > - Change dict, to not be an opaque structure , but an array of data elements > which is a union of (int, string etc.). > - Backward compatibility issues is when the newer server/client adds data to > dict but the old client/server fails to read the dict. This is the > responsibility of the programmer to make sure, thta this case doesn't fail > silently, op version can be used if it is done as a part of adding new > feature/volume set. Another approach would be, if client has a list of > capabilities(features) the server supports it can accordingly tune itself to > access the xdata. > > Regards, > Poornima > > _______________________________________________ Gluster-devel mailing list [email protected] http://www.gluster.org/mailman/listinfo/gluster-devel
