Message-ID: <4368F966.20901@gmail.com>
Date: Wed, 02 Nov 2005 11:37:42 -0600
From: Hareesh Nagarajan <hnagar2@gmail.com>
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To: Coywolf Qi Hunt <qiyong@fc-cn.com>
CC: Linux Kernel Development <linux-kernel@vger.kernel.org>, akpm@osdl.org
Subject: Re: [PATCH] register_filesystem() must return -EEXIST if the filesystem
 with the same name is already registered
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Coywolf Qi Hunt wrote:
> On Wed, Nov 02, 2005 at 02:42:12AM -0600, Hareesh Nagarajan wrote:
>> If we have a look at the register_filesystem() function defined in 
>> fs/filesystems.c, we see that if a filesystem with a same name has 
>> already been registered then the find_filesystem() function will return 
>> NON-NULL otherwise it will return NULL.
>>
>> Hence, register_filesystem() should return EEXIST instead of EBUSY. 
>> Returning EBUSY is misleading (unless of course I'm missing something 
>> obvious) to the caller of register_filesystem().
> 
> This `slot' is buy, so EBUSY makes sense. Filesytem is not file, hence
> EEXIST doesn't apply IMHO.

Earlier this week, my calls to register_filesystem(struct 
file_system_type * fs) were failing returning an -EBUSY. Now I didn't 
know if it was failing because of:
	if (fs->next)	return -EBUSY;
Or:
	p = find_filesystem(fs->name);
         if (*p)	res = -EBUSY;
	...
	return res;

It is for this reason I thought it would make sense to differentiate 
between the two points of failure.

Hareesh Nagarajan
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