On Fri, Aug 20, 2010 at 07:53:03PM +1000, Neil Brown wrote: > On Fri, 20 Aug 2010 04:30:57 -0400 > Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > > Suddenly getting an file pointer for a symlink which could never happen > > before is a really bad idea. Just add a proper readlink_by_handle > > system call, similar to what's done in the XFS interface. > > Why is that? > With futexes we suddenly get a file descriptor for something we could never > get a file descriptor on before and that doesn't seem to be a problem. > > Why should symlinks be special as the only thing that you cannot have a file > descriptor for? Uniformity of interface is a very valuable property. You are welcome to review the codepaths around pathname resolution for assumptions of presense of ->follow_link() and friends; there _are_ subtle cases and dumping your "opened symlinks" in there is far from a trivial change. Note that it affects more than just the starting points of lookups; /proc/*/fd/* stuff is also involved. BTW, speaking of NULL pathname, linkat() variant that allows creating a link to an opened file is also a very dubious thing; at the very least, you get non-trivial security implications, since now a process that got an opened descriptor passed to it by somebody else may create hardlinks to the sucker. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
