On Thu, Apr 24, 2008 at 05:37:39PM +0200, Miklos Szeredi wrote: > > > What is left is the guarantee, that the race-free r/o remounts will ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > always work and some obscure caller didn't forget to surround it with ^^^^^^^^^^^^^^^^^ > Why are those so important? Yes, if we have multiple vfs_() calls, > surround them with an extra want/drop pair. Which leaves you with the same need to audit all these suckers anyway. I'm in principle fine with having such helper functions, *IF* they are not sold as providing all protection one needs, *IF* you are not expecting to be able to fold all areas down into them and *IF* original ones are left intact. Modulo the like path_rename(), BTW - that one is just plain ugly API. > > We don't even have many callers of each, and with a few we do it's not > > obvious that we want to go through vfsmounts (and vfsmount-based checks) > > in all of them. So no, I don't buy your argument. Sorry. > > > > I'm not even convinced that they are useful as helpers, at least until > > we'd decided what to do with checks in nfsd. Until then we do, as > > far as I'm concerned, one place where they would definitely DTRT - fs/namei.c. > > And I want more than one caller before merging those, > > unix_bind() -> vfs_mknod() > sys_mq_unlink() -> vfs_unlink() > open.c (several) -> notify_change() > *setxattr() -> vfs_setxattr() > *removexattr() -> vfs_removexattr() OK. > > let alone removing the interface that doesn't require checks to be > > vfsmount-based for all users. > > What users? There are paractically _no_ other users. The ones that > there are (like reiserfs) should not be using them, and there are > already some patches cleaning that mess up. OK, explain me, in small words, WTF should something that wants to do operations on filesystem tree have a vfsmount. Slowly. And "r/o bind loses value if it can be bypassed" is a hogwash - fs methods are still there, so it *can* be bypassed just fine, thank you very much. It's really up to caller. "But they won't be able to do open()" also doesn't fly - again, it's up to whoever writes particular piece of code. -- 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
