Re: [PATCH 3/3] ovl: redirect on rename-dir

From	Konstantin Khlebnikov <koct9i@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] ovl: redirect on rename-dir
Date	2016-11-07 11:10 +0100
Message-ID	<sAP2i-1FI-43@gated-at.bofh.it> (permalink)
References	(3 earlier) <swups-2Sj-39@gated-at.bofh.it> <sAB90-11R-5@gated-at.bofh.it> <sANaa-gv-3@gated-at.bofh.it> <sAOSB-1m1-27@gated-at.bofh.it> <sAP2h-1FI-17@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Nov 7, 2016 at 1:04 PM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> On Mon, Nov 7, 2016 at 10:58 AM, Konstantin Khlebnikov <koct9i@gmail.com> wrote:
>
>> I've stumbled on somehow related problem - concurrent copy-ups are
>> strictly serialized by rename locks.
>> Obviously, file copying could be done in parallel: locks are required
>> only for final rename.
>> Because of that overlay slower that aufs for some workloads.
>
> Easy to fix: for each copy up create a separate subdir of "work".
> Then the contention is only for the time of creating the subdir, which
> is very short.

Yeah, but lock_rename() also takes per-sb s_vfs_rename_mutex (kludge by Al Viro)
I think proper synchronization for concurrent copy-up (for example
round flag on ovl_entry) and  locking rename only for rename could be
better.

Thread

Re: [PATCH 3/3] ovl: redirect on rename-dir Konstantin Khlebnikov <koct9i@gmail.com> - 2016-11-06 20:20 +0100
  Re: [PATCH 3/3] ovl: redirect on rename-dir Miklos Szeredi <miklos@szeredi.hu> - 2016-11-07 09:10 +0100
    Re: [PATCH 3/3] ovl: redirect on rename-dir Konstantin Khlebnikov <koct9i@gmail.com> - 2016-11-07 11:00 +0100
      Re: [PATCH 3/3] ovl: redirect on rename-dir Miklos Szeredi <miklos@szeredi.hu> - 2016-11-07 11:10 +0100
        Re: [PATCH 3/3] ovl: redirect on rename-dir Konstantin Khlebnikov <koct9i@gmail.com> - 2016-11-07 11:10 +0100
          Re: [PATCH 3/3] ovl: redirect on rename-dir Amir Goldstein <amir73il@gmail.com> - 2016-11-07 18:50 +0100
            Re: [PATCH 3/3] ovl: redirect on rename-dir Amir Goldstein <amir73il@gmail.com> - 2016-11-11 00:00 +0100
              Re: [PATCH 3/3] ovl: redirect on rename-dir Konstantin Khlebnikov <koct9i@gmail.com> - 2016-11-11 10:50 +0100
                Re: [PATCH 3/3] ovl: redirect on rename-dir Miklos Szeredi <miklos@szeredi.hu> - 2016-11-11 11:10 +0100
                Re: [PATCH 3/3] ovl: redirect on rename-dir Amir Goldstein <amir73il@gmail.com> - 2016-11-11 13:50 +0100
  Re: [PATCH 3/3] ovl: redirect on rename-dir Raphael Hertzog <hertzog@debian.org> - 2016-11-07 12:10 +0100
    Re: [PATCH 3/3] ovl: redirect on rename-dir Konstantin Khlebnikov <koct9i@gmail.com> - 2016-11-07 12:40 +0100
      Re: [PATCH 3/3] ovl: redirect on rename-dir Raphael Hertzog <hertzog@debian.org> - 2016-11-07 14:50 +0100
        Re: [PATCH 3/3] ovl: redirect on rename-dir Miklos Szeredi <miklos@szeredi.hu> - 2016-11-10 23:40 +0100
          Re: [PATCH 3/3] ovl: redirect on rename-dir Konstantin Khlebnikov <koct9i@gmail.com> - 2016-11-11 10:50 +0100

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