From: Trond Myklebust <trond.myklebust@fys.uio.no>
Subject: Re: historical question: nfs_rename()
Date: Tue, 18 Oct 2005 09:10:29 -0700
Message-ID: <1129651829.8989.17.camel@lade.trondhjem.org>
References: <044B81DE141D7443BCE91E8F44B3C1E288E56A@exsvl02.hq.netapp.com>
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To: "Lever, Charles" <Charles.Lever@netapp.com>
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m=C3=A5 den 17.10.2005 klokka 12:12 (-0700) skreiv Lever, Charles:
> a customer recently pointed out that the rename(2) system call does not
> allow replacing directories, even if they are empty.  RFC1813 at least
> suggests that the server and protocol do allow directory replacement, as
> long as the target is empty.
>=20
> the culprit appears to be this check in nfs_rename()
>=20
>         if (S_ISDIR(new_inode->i_mode))
>                 goto out;
>=20
> which causes nfs_rename() to return -EBUSY if the target is a directory.
>=20
> is there a historical reason why the Linux NFS client does not allow
> directory replacement?  shouldn't the error code be -EISDIR for this
> case?

Yes, the error should be EISDIR. I'm not sure that I agree with your
assertion that rename failing is an NFS-only issue, though. The attached
testcase fails on both XFS and ext3 too with the error "Rename failed:
Is a directory".

Cheers,
  Trond


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#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>

#define FILENAME "gnurr"
#define DIRNAME "gnarg"

void die(char *errmsg)
{
	perror(errmsg);
	exit(1);
}

int main()
{
	int fd;
	int err;

	fd = open(FILENAME, O_CREAT|O_EXCL|O_RDWR, 0644);
	if (fd < 0)
		die("File creation failed");
	close(fd);
	err = mkdir(DIRNAME, 0700);
	if (err != 0)
		die("Directory creation failed");
	err = rename("gnurr", "gnarg");
	if (err != 0)
		die("Rename failed");
}

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