mkdir -p fails when directory exists

Question

On one of our remote systems mkdir -p $directory fails when the directory exists. which means it shows

mkdir: cannot create directory '$directory' : file exists

This is really puzzling, as I believed the contract of -p was that is always succeed when the directory already exists. And it works on the other systems I tried.

there is a user test on all of these systems, and directory=/home/test/tmp.

Solution 1

This could be caused if there is already a file by the same name located in the directory.

Note that a directory cannot contain both a file and folder by the same name on linux machines.

Solution 2

Check to see if there is a file (not a directory) with a name same as $directory.

Solution 3

mkdir -p won't create directory if there is a file with the same name is existing in the same directory. Otherwise it will work as expected.

Solution 4

Was your directory a FUSE-based network mount by any chance?

In addition to a file with that name already existing (other answer), this can happen when a FUSE process that once mounted something at this directory crashed (or was killed, e.g. with kill -9 or via the Linux OOM killer).

To see what is happening in detail, run strace -fy mkdir -p $directory, which shows all syscalls involved and their return values.

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I consider the error messages emitted in this case a bug in mkdir -p (in particular the gnulib library):

When you run it on a dir that had a FUSE process mounted but that process crashed, it says

mkdir: cannot create directory ‘/mymount’: File exists

which is rather highly inaccurate, because the underlying stat() call returns ENOTCONN (Transport endpoint is not connected); but mkdir propagates up the less-specific error from the previous mkdir() sycall. It's extra confusing because the man page says:

   -p, --parents
          no error if existing, make parent directories as needed

so it shouldn't error if the dir exists, yet ls -l / shows:

d????????? ? ?    ?       ?            ? files

so according to this (d), it is a directory, but it isn't according to test -d.

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I believe a better error message (which mkdir -p should emit in this case) would be:

mkdir: cannot create directory ‘/mymount’: Transport endpoint is not connected

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