On Mon, Sep 30, 2013 at 07:02:23PM -0700, Linus Torvalds wrote: > Shouldn't a cmpxchg() in just the dup2 code solve that? > > If the old value was NULL, you'd have to repeat and go back and see if > the open_fds[] bit had been cleared in the meantime (ie it's NULL not > because somebody else is busy installing it, but because somebody just > uninstalled it). Yechh... Under ->file_lock (in do_dup2()), hopefully? Or you'll get all kinds of fun with close() thrown into the game, as well... > But yeah, I do agree that that sounds nasty and a complication I > hadn't even thought about. dup2() does violate our normal "let's > pre-allocate the fd slot" rule. Ugh. Hell knows... Descriptor handling *is* pretty well isolated these days, so it just might be doable without disrupting the living hell out of anything else. fs/file.c is pretty much it - everything else goes through it. I've enough on my plate at the moment with fs/namespace.c and fs/namei.c, though, and praying hard fs/inode.c doesn't enter the game. I _know_ that fs/notify will and I'm not enjoying that for a second. BTW, has eparis resurfaced with any fixes for *notify/umount races? I don't seem to have anything related in the mailbox, but... -- 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
