Messages in this thread | | | Date | Fri, 15 Mar 2013 20:30:18 +0000 | From | Al Viro <> | Subject | Re: [PATCH 0/9] overlay filesystem: request for inclusion (v17) |
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On Sat, Mar 16, 2013 at 03:57:18AM +0900, J. R. Okajima wrote: > > Al Viro: > > The trouble with such mechanisms is that they tend to end up depending on > > fairly non-trivial properties of underlying fs. Try aufs one on btrfs, > > see how soon you spot the problem. It's nice when a method turns out > > to be really redundant and implementable in uniform way via other methods > > present; see fh_to_dentry history for example of situation where it hadn't... > > Hmm, I could not see problem around aufs using btrfs as the upper RW > branch, tested on linux-3.9-rc2. > Would you describe more specifically?
Sure - btrfs happens to have an interesting limit on the number of links to the same object located in one directory.
The thing is, you are trying to retrofit a new primitive into many filesystems and do it in the same way. Doesn't work well...
And yes, it is an independent primitive. What I really don't understand is WTF is so attractive about not having to touch individual filesystems; it's not particulary hard to do for any fs we might care about...
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