linux-kernel - Re: [RFC] st_nlink after rmdir() and rename()

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Date:	Thu, 03 Mar 2011 17:17:32 +0100
From:	Andreas Schwab <schwab@...hat.com>
To:	Theodore Tso <tytso@....EDU>
Cc:	Al Viro <viro@...IV.linux.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC] st_nlink after rmdir() and rename()

Theodore Tso <tytso@....EDU> writes:

> On Mar 2, 2011, at 10:24 PM, Al Viro wrote:
>
>> We have an interesting problem.  Consider the following sequence
>> of syscalls:
>> 	mkdir("foo", 0777);
>> 	mkdir("bar", 0777);
>> 	fd1 = open("foo", O_DIRECTORY);
>> 	fd2 = open("bar", O_DIRECTORY);
>> 	rename("foo", "bar");	/* kill old bar */
>
> I must be missing something.  I didn't think you could rename on
> top of a directory and have the directory disappear.  Don't you get
> an error in that case?

rename is required to be able to move a directory over an empty
directory, atomically.

> What happens if bar contains files?

That's an error.

Andreas.

-- 
Andreas Schwab, schwab@...hat.com
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