From: Ted Ts'o <tytso@mit.edu>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH] ext4: fix races in ext4_sync_parent()
Date: Wed, 27 Jul 2011 20:34:22 -0400 [thread overview]
Message-ID: <20110728003421.GA3133@thunk.org> (raw)
In-Reply-To: <20110727011554.GN22133@ZenIV.linux.org.uk>
On Wed, Jul 27, 2011 at 02:15:54AM +0100, Al Viro wrote:
> On Tue, Jul 26, 2011 at 09:13:12PM -0400, Theodore Ts'o wrote:
> > + inode = igrab(inode);
> > + while (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
> > ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
> > - dentry = list_entry(inode->i_dentry.next,
> > - struct dentry, d_alias);
> > - if (!dentry || !dentry->d_parent || !dentry->d_parent->d_inode)
> > + dentry = list_first_entry(&inode->i_dentry,
> > + struct dentry, d_alias);
>
> ... and what if you don't have a dentry for that inode anymore?
I thought you were complaining that dentry could never be NULL
earlier? We earlier checked for NULL, but I figured you knew
something I didn't....
> > + next = igrab(dentry->d_parent->d_inode);
>
> what protects you against rename() (OK, d_mode()) here?
Does it matter? We'll get either the old or the new parent directory,
but either way it will be a valid inode, right? Or am I missing
something?
- Ted
next prev parent reply other threads:[~2011-07-28 0:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-27 1:13 [PATCH] ext4: fix races in ext4_sync_parent() Theodore Ts'o
2011-07-27 1:15 ` Al Viro
2011-07-28 0:34 ` Ted Ts'o [this message]
2011-07-28 1:11 ` Al Viro
2011-07-30 16:32 ` Ted Ts'o
2011-07-30 16:42 ` Al Viro
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