| Subject: | Race condition |
Hi
I'm currently using File::Path with perl5.8.3 on a 64 bits linux machine.
I have some questions about mkpath function in the perl package
File::path you support.
I would like to know if you take into account race conditions for it.
Let me give you more details.
I have several scripts that are run in parallel and try to create a
directory (kind of “mkdir –p” command).
I have some issues when using unix command “mkdir –p” at the same time
For example:
%mkdir –p /a/b/c
%mkdir –p /a/b/d
If b doesn’t exist at run time, irst script will try to create it, while
second script will try to write in it whereas it is not completely created.
Indeed I found this article to explain the behavior:
Second, is that `mkdir -p` does not work for parallel builds. This
occurs when make tries to invoke, for example, `mkdir -p /a/b` and
`mkdir -p /a/c` in parallel, with directory /a being non-existent. What
`mkdir -p` does is that first it stats /a directory and if it does not
exist it tries to create that. There is a race condition between
stat'ing the directory and creating it, during which another parallel
invocation of mkdir creates this same directory, which causes creating
/a directory in the former mkdir to return EEXIST and fail. It must be
mkdir bug (both gnu and Solaris), but I not sure if it can be fixed in
mkdir, since if creating a directory returns EEXIST, that directory
needs to be stat'ed again, to make sure it is a directory and not a
file, leading to a race condition again. (no POSIX interface to create a
directory and if that name already exists in the filesystem return its
type).
I wanted to know if mkpath function can solve this issue.
Thanks for your answer.
Didier