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From: Jeff King <peff@peff.net>
To: Elijah Newren <newren@gmail.com>
Cc: Eric Sunshine <sunshine@sunshineco.com>,
	Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>,
	Git List <git@vger.kernel.org>
Subject: Re: [PATCH 1/5] t7300: add testcase showing unnecessary traversal into ignored directory
Date: Fri, 7 May 2021 19:05:17 -0400	[thread overview]
Message-ID: <YJXHrXWVDSgg5TZw@coredump.intra.peff.net> (raw)
In-Reply-To: <CABPp-BGzUBF8S8t3nixi3TCkiBe7oS1fQ5cNCozicb20iZxshA@mail.gmail.com>

On Thu, May 06, 2021 at 10:00:49PM -0700, Elijah Newren wrote:

> > > +               >directory-random-file.txt &&
> > > +               # Put this file under directory400/directory399/.../directory1/
> > > +               depth=400 &&
> > > +               for x in $(test_seq 1 $depth); do
> > > +                       mkdir "tmpdirectory$x" &&
> > > +                       mv directory* "tmpdirectory$x" &&
> > > +                       mv "tmpdirectory$x" "directory$x"
> > > +               done &&
> >
> > Is this expensive/slow loop needed because you'd otherwise run afoul
> > of command-line length limits on some platforms if you tried creating
> > the entire mess of directories with a single `mkdir -p`?
> 
> The whole point is creating a path long enough that it runs afoul of
> limits, yes.
> 
> If we had an alternative way to check whether dir.c actually recursed
> into a directory, then I could dispense with this and just have a
> single directory (and it could be named a single character long for
> that matter too), but I don't know of a good way to do that.  (Some
> possiibilities I considered along that route are mentioned at
> https://lore.kernel.org/git/CABPp-BF3e+MWQAGb6ER7d5jqjcV=kYqQ2stM_oDyaqvonPPPSw@mail.gmail.com/)

I don't have a better way of checking the dir.c behavior. But I think
the other half of Eric's question was: why can't we do this setup way
more efficiently with "mkdir -p"?

I'd be suspicious that it would work portably because of the long path.
But I think the perl I showed earlier would create it in much less time:

  $ touch directory-file
  $ time sh -c '
      for x in $(seq 1 400)
      do
        mkdir tmpdirectory$x &&
	mv directory* tmpdirectory$x &&
	mv tmpdirectory$x directory$x
      done
    '
    real	0m2.222s
    user	0m1.481s
    sys		0m0.816s

  $ time perl -e '
      for (reverse 1..400) {
        my $d = "directory$_";
	mkdir($d) and chdir($d) or die "mkdir($d): $!";
      }
      open(my $fh, ">", "some-file");
    '
    real	0m0.010s
    user	0m0.001s
    sys		0m0.009s

-Peff

  parent reply	other threads:[~2021-05-07 23:05 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-07  4:04 [PATCH 0/5] Directory traversal fixes Elijah Newren via GitGitGadget
2021-05-07  4:04 ` [PATCH 1/5] t7300: add testcase showing unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-07  4:27   ` Eric Sunshine
2021-05-07  5:00     ` Elijah Newren
2021-05-07  5:31       ` Eric Sunshine
2021-05-07  5:42         ` Elijah Newren
2021-05-07  5:56           ` Eric Sunshine
2021-05-07 23:05       ` Jeff King [this message]
2021-05-07 23:15         ` Eric Sunshine
2021-05-08  0:04         ` Elijah Newren
2021-05-08  0:10           ` Eric Sunshine
2021-05-08 17:20             ` Elijah Newren
2021-05-08 11:13   ` Philip Oakley
2021-05-08 17:20     ` Elijah Newren
2021-05-07  4:04 ` [PATCH 2/5] t3001, t7300: add testcase showcasing missed directory traversal Elijah Newren via GitGitGadget
2021-05-07  4:04 ` [PATCH 3/5] dir: avoid unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-07  4:04 ` [PATCH 4/5] dir: traverse into untracked directories if they may have ignored subfiles Elijah Newren via GitGitGadget
2021-05-07  4:05 ` [PATCH 5/5] [RFC] ls-files: error out on -i unless -o or -c are specified Elijah Newren via GitGitGadget
2021-05-07 16:22 ` [PATCH 6/5] dir: update stale description of treat_directory() Derrick Stolee
2021-05-07 17:57   ` Elijah Newren
2021-05-07 16:27 ` [PATCH 0/5] Directory traversal fixes Derrick Stolee
2021-05-08  0:08 ` [PATCH v2 0/8] " Elijah Newren via GitGitGadget
2021-05-08  0:08   ` [PATCH v2 1/8] t7300: add testcase showing unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-08 10:13     ` Junio C Hamano
2021-05-08 17:34       ` Elijah Newren
2021-05-08 10:19     ` Junio C Hamano
2021-05-08 17:41       ` Elijah Newren
2021-05-08  0:08   ` [PATCH v2 2/8] t3001, t7300: add testcase showcasing missed directory traversal Elijah Newren via GitGitGadget
2021-05-08  0:08   ` [PATCH v2 3/8] dir: avoid unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-08  0:08   ` [PATCH v2 4/8] dir: traverse into untracked directories if they may have ignored subfiles Elijah Newren via GitGitGadget
2021-05-08  0:08   ` [PATCH v2 5/8] [RFC] ls-files: error out on -i unless -o or -c are specified Elijah Newren via GitGitGadget
2021-05-08  0:08   ` [PATCH v2 6/8] dir: update stale description of treat_directory() Derrick Stolee via GitGitGadget
2021-05-08  0:08   ` [PATCH v2 7/8] [RFC] dir: convert trace calls to trace2 equivalents Elijah Newren via GitGitGadget
2021-05-08  0:08   ` [PATCH v2 8/8] [RFC] dir: reported number of visited directories and paths with trace2 Elijah Newren via GitGitGadget
2021-05-08 19:58   ` [PATCH v3 0/8] Directory traversal fixes Elijah Newren via GitGitGadget
2021-05-08 19:58     ` [PATCH v3 1/8] [RFC] dir: convert trace calls to trace2 equivalents Elijah Newren via GitGitGadget
2021-05-10  4:49       ` Junio C Hamano
2021-05-11 17:23         ` Elijah Newren
2021-05-11 16:17       ` Jeff Hostetler
2021-05-11 17:29         ` Elijah Newren
2021-05-08 19:58     ` [PATCH v3 2/8] [RFC] dir: report number of visited directories and paths with trace2 Elijah Newren via GitGitGadget
2021-05-10  5:00       ` Junio C Hamano
2021-05-08 19:58     ` [PATCH v3 3/8] [RFC] ls-files: error out on -i unless -o or -c are specified Elijah Newren via GitGitGadget
2021-05-10  5:09       ` Junio C Hamano
2021-05-11 17:40         ` Elijah Newren
2021-05-11 22:32           ` Junio C Hamano
2021-05-08 19:59     ` [PATCH v3 4/8] t7300: add testcase showing unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-10  5:28       ` Junio C Hamano
2021-05-11 17:45         ` Elijah Newren
2021-05-11 22:43           ` Junio C Hamano
2021-05-12  2:07             ` Elijah Newren
2021-05-12  3:17               ` Junio C Hamano
2021-05-08 19:59     ` [PATCH v3 5/8] t3001, t7300: add testcase showcasing missed directory traversal Elijah Newren via GitGitGadget
2021-05-08 19:59     ` [PATCH v3 6/8] dir: avoid unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-10  5:48       ` Junio C Hamano
2021-05-11 17:57         ` Elijah Newren
2021-05-08 19:59     ` [PATCH v3 7/8] dir: traverse into untracked directories if they may have ignored subfiles Elijah Newren via GitGitGadget
2021-05-08 19:59     ` [PATCH v3 8/8] dir: update stale description of treat_directory() Derrick Stolee via GitGitGadget
2021-05-11 18:34     ` [PATCH v4 0/8] Directory traversal fixes Elijah Newren via GitGitGadget
2021-05-11 18:34       ` [PATCH v4 1/8] dir: convert trace calls to trace2 equivalents Elijah Newren via GitGitGadget
2021-05-11 19:06         ` Jeff Hostetler
2021-05-11 20:12           ` Elijah Newren
2021-05-11 23:12             ` Jeff Hostetler
2021-05-12  0:44               ` Elijah Newren
2021-05-12 12:26                 ` Jeff Hostetler
2021-05-12 15:24                   ` Elijah Newren
2021-05-11 18:34       ` [PATCH v4 2/8] dir: report number of visited directories and paths with trace2 Elijah Newren via GitGitGadget
2021-05-11 18:34       ` [PATCH v4 3/8] ls-files: error out on -i unless -o or -c are specified Elijah Newren via GitGitGadget
2021-05-11 18:34       ` [PATCH v4 4/8] t7300: add testcase showing unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-11 18:34       ` [PATCH v4 5/8] t3001, t7300: add testcase showcasing missed directory traversal Elijah Newren via GitGitGadget
2021-05-11 18:34       ` [PATCH v4 6/8] dir: avoid unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-11 18:34       ` [PATCH v4 7/8] dir: traverse into untracked directories if they may have ignored subfiles Elijah Newren via GitGitGadget
2021-05-11 18:34       ` [PATCH v4 8/8] dir: update stale description of treat_directory() Derrick Stolee via GitGitGadget
2021-05-12 17:28       ` [PATCH v5 0/9] Directory traversal fixes Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 1/9] dir: convert trace calls to trace2 equivalents Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 2/9] dir: report number of visited directories and paths with trace2 Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 3/9] ls-files: error out on -i unless -o or -c are specified Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 4/9] t7300: add testcase showing unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 5/9] t3001, t7300: add testcase showcasing missed directory traversal Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 6/9] dir: avoid unnecessary traversal into ignored directory Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 7/9] dir: traverse into untracked directories if they may have ignored subfiles Elijah Newren via GitGitGadget
2021-05-12 17:28         ` [PATCH v5 8/9] dir: update stale description of treat_directory() Derrick Stolee via GitGitGadget
2021-05-17 17:20           ` Derrick Stolee
2021-05-17 19:44             ` Junio C Hamano
2021-05-18  3:32               ` Elijah Newren
2021-05-19  1:44                 ` Junio C Hamano
2021-05-12 17:28         ` [PATCH v5 9/9] dir: introduce readdir_skip_dot_and_dotdot() helper Elijah Newren via GitGitGadget
2021-05-17 17:22           ` Derrick Stolee
2021-05-18  3:34             ` Elijah Newren
2021-05-17 17:23         ` [PATCH v5 0/9] Directory traversal fixes Derrick Stolee

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