Messages in this thread | | | Date | Thu, 22 Mar 2012 15:09:45 +0000 | From | Al Viro <> | Subject | Re: [PATCH v3 10/12] ima: defer calling __fput() |
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On Thu, Mar 22, 2012 at 10:53:04AM -0400, Mimi Zohar wrote: > > BTW, you've missed several other places in mm/* doing fput(), so it wouldn't > > be enough to paper over your problem anyway. > > > > Final fput() *can* happen under mmap_sem. Period. > > I think I got that loud and clear; otherwise we wouldn't have come up > with deferring the __fput(). We have a very real problem here - writing > extended attributes requires taking the i_mutex.
Don't do it, then? If you _must_ write to xattr on final fput, I'd suggest starting to figure out if xattr needs its protection to be ->i_mutex - it might make sense to introduce a separate mutex for xattr crap. Or not - I'm not familiar enough with the guts of xattr handling in individual filesystems to tell if that would work (e.g. if it would need unpleasant changes to ->setattr() instances)...
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