NFSv4.2 fix problems with __nfs42_ssc_open

In the Linux kernel, the following vulnerability has been resolved: NFSv4.2 fix problems with __nfs42_ssc_open A destination server while doing a COPY shouldn't accept using the passed in filehandle if its not a regular filehandle. If alloc_file_pseudo() has failed, we need to decrement a reference on the newly created inode, otherwise it leaks.