Messages in this thread | | | Date | Thu, 18 Feb 1999 11:59:35 -0500 (EST) | From | Alexander Viro <> | Subject | Re: fsync on large files |
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On Thu, 18 Feb 1999, Raul Miller wrote:
> Alexander Viro <viro@math.psu.edu> wrote: > > mkdir a > > mkdir b > > mkdir a/c > > ln a/c b/c > > mkdir a/c/d > > mv b a/c/d > > > > If you have a way to deal with that... BTW, I strongly suspect > > that any solution involving scanning potential ancestors is *not* good - > > you can construct very unpleasant DoS that way. > > You might be able to get away with having a list of parents structure > on multiply linked directories, which would have to be mirrored in > dcache.
And backtracing all possible ways? And that means sucking *all* parents (and their parents, etc.) into dcache on a lookup. I.e. doing lookups in arbitrary (worse yet, unknown when we start) number of directories. We need to hold semaphores on lookup. Could you spell "priority inversions and deadlocks"?
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