From: Eric Biggers <ebiggers3@gmail.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: fs/namei.c: Misuse of sequence counts?
Date: Sat, 11 Oct 2014 23:01:42 -0500 [thread overview]
Message-ID: <20141012040142.GB24463@zzz> (raw)
In-Reply-To: <20141012001259.GM7996@ZenIV.linux.org.uk>
On Sun, Oct 12, 2014 at 01:12:59AM +0100, Al Viro wrote:
>
> Huh? What's to guarantee that dentry hasn't become negative since the
> moment we'd fetched the seqcount? _That_ is the problem we are dealing
> with here - link_path_walk() relies on nd->inode being non-NULL.
Hmm, I guess that makes sense. So the code is actually verifying that the inode
is still the inode that was referenced from the current or root directory when
nd->path was set. But couldn't the problem also be solved by setting nd->inode
directly in the fs->seq retry loops? (The file descriptor case could be
'nd->inode = file_inode(f.file);'.) Then there would be no need for the extra
read_seqcount_retry() just for the inode. The patch you posted looks correct,
but I wonder if this approach would be better.
next prev parent reply other threads:[~2014-10-12 4:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-11 22:58 fs/namei.c: Misuse of sequence counts? Eric Biggers
2014-10-11 23:46 ` Al Viro
2014-10-12 3:55 ` Eric Biggers
2014-10-12 4:29 ` Al Viro
2014-10-12 0:12 ` Al Viro
2014-10-12 4:01 ` Eric Biggers [this message]
2014-10-12 4:37 ` Al Viro
2014-10-12 4:51 ` Eric Biggers
2014-10-12 5:08 ` Eric Biggers
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