On Monday, 02/16/2004 at 02:09 CST, Adam Thornton <[EMAIL PROTECTED]> wrote: > So I have a guest whose /usr I want to freeze and stick into a DCSS. > > I can easily do this if the DCSS is SW or EW. > > But I really want an SR DCSS, since I want everyone to share the > filesystem but I don't want anyone (except the owner) to write to it > ever, and the owner only to do so very infrequently. > > Can I modify the permissions on a DCSS to do this? > > If not, how can I do the initial load of the DCSS? > > Rick Troth has a way of doing it where he mounts a scratch disk, mounts > a file via the loopback driver, and then copies the filesystem into the > file on the scratch disk. Then he uses FTP or something like that to > get the file into CMS space, and then a pipeline to force the contents > of the file into storage. All this before the SAVESEG. > > That seems a little kludgey to me. Especially since if I have the > segment W, I can just mount /proc/dcssblk/SHRUSR and do a "cp -a" to > load it up. But then I don't know how, having done that and then saved > the segment, I can prevent anyone else from writing the segment. > > Help?
Did you try the sequence I gave last week? The trick, I believe, is to load the SR segment in exclusive write mode, which gives you a private non-shared r/w copy of a r/o DCSS. When you do that, mount it, fill it, and save it, no one can change the segment. At most they, too, can load an exclusive write copy which is really a private copy. So, don't define it SW. Define it SR. Alan Altmark Sr. Software Engineer IBM z/VM Development
