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From: Al Viro <viro@ZenIV.linux.org.uk>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>,
	Ivan Delalande <colona@arista.com>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] vfs: Fix, simpliy and stop using d_dname for the /proc/*/ns/* files.
Date: Thu, 21 May 2015 00:23:25 +0100	[thread overview]
Message-ID: <20150520232325.GA7232@ZenIV.linux.org.uk> (raw)
In-Reply-To: <87bnhedhw5.fsf_-_@x220.int.ebiederm.org>

On Wed, May 20, 2015 at 05:05:30PM -0500, Eric W. Biederman wrote:

> -	dentry = d_alloc_pseudo(mnt->mnt_sb, &qname);
> +	dentry = d_alloc_name(mnt->mnt_root, name);
>  	if (!dentry) {
>  		iput(inode);
>  		mntput(mnt);
>  		return ERR_PTR(-ENOMEM);
>  	}
> -	d_instantiate(dentry, inode);
> +	d_add(dentry, inode);

Careful - that might have non-trivial effects.  Namely, you are making
the root dentry of that sucker a contention point and adding to hash
pollution...  It's probably not going to cause visible problems, but
it's worth profiling just to be sure.

Besides, you are violating a bunch of rules here - several hashed
children of the same directory with the same name all at once...
not nice.

  parent reply	other threads:[~2015-05-20 23:23 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-15 18:58 Warning: empty root dentry name after lazy mount removal Ivan Delalande
2015-05-20 10:05 ` Omar Sandoval
2015-05-20 22:05   ` [PATCH] vfs: Fix, simpliy and stop using d_dname for the /proc/*/ns/* files Eric W. Biederman
2015-05-20 23:00     ` Omar Sandoval
2015-05-20 23:08     ` Ivan Delalande
2015-05-20 23:23     ` Al Viro [this message]
2015-06-03 20:51       ` Ivan Delalande
2015-06-06 19:27         ` Eric W. Biederman
2015-06-06 19:30           ` [PATCH] vfs: Remove incorrect debugging WARN in prepend_path Eric W. Biederman
2015-06-06 20:08           ` [PATCH] vfs: Fix, simpliy and stop using d_dname for the /proc/*/ns/* files Ivan Delalande

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