linux-kernel - Re: Bug: getcwd: cannot access parent directories

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Date:   Thu, 27 Sep 2018 11:54:15 +1000
From:   Roel Van de Paar <roel.vandepaar@...cona.com>
To:     linux-kernel@...r.kernel.org
Subject: Re: Bug: getcwd: cannot access parent directories

Ping :)

On 21 September 2018 at 18:16, Roel Van de Paar
<roel.vandepaar@...cona.com> wrote:
>
> [1.] One line summary of the problem:
>
> "cd: error retrieving current directory: getcwd: cannot access parent
> directories: No such file or directory" on move of directories to
> another volume
>
> [2.] Full description of the problem/report:
>
> Example output (testcase below):
>
> /tmp/1/2$ cd ..
> cd: error retrieving current directory: getcwd: cannot access parent
> directories: No such file or directory
> /tmp/1/2/..$ cd ..
> cd: error retrieving current directory: getcwd: cannot access parent
> directories: No such file or directory
> /tmp/1/2/../..$ cd ..
> cd: error retrieving current directory: getcwd: cannot access parent
> directories: No such file or directory
> /tmp/1/2/../../..$ cd ..
> cd: error retrieving current directory: getcwd: cannot access parent
> directories: No such file or directory
> /tmp/1/2/../../../..$ cd ..
> cd: error retrieving current directory: getcwd: cannot access parent
> directories: No such file or directory
> /tmp/1/2/../../../../..$ cd ..
> cd: error retrieving current directory: getcwd: cannot access parent
> directories: No such file or directory
> /tmp/1/2/../../../../../..$ cd ..
> /tmp$
>
> - The number of ".." required is not correct
> - The number of ".." matches the number of subdirs (see below)
>
> [4.] Kernel information
>
> Tested on latest updates of:
> * Ubuntu Xenial
> * Ubuntu Bionic
> * Centos 7
>
> [7.] A small shell script or example program which triggers the
> problem (if possible)
>
> In session 1
>   cd /tmp
>   mkdir -p 1/2
>   cd 1/2
>
> In session 2 (another terminal session)
>   cd /tmp
>   mkdir -p 3/4/5/6/7
>   mv 1 3/4/5/6/7
>   mv 3 /dev/shm   # where /dev/shm is some other disk. /dev/shm
> reproduction works too. If the disk is the same, the issue will not
> show.
>
> Back to session 1
>   cd ..   # fail
>   cd ..   # fail
>   cd ..   # fail
>   cd ..   # fail
>   cd ..   # fail
>   cd ..   # fail
>   cd ..   # works, but to completely incorrect directory given the
> many 'cd ..'```
>
> The problem is made more clear here by using 3/4/5/6/7 but you can
> also just use a single subdir to see it

Roel Van de Paar, Technical Director - Quality Assurance, Percona