From: David Howells <dhowells@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: dhowells@redhat.com, Al Viro <viro@zeniv.linux.org.uk>,
Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-unionfs@vger.kernel.org" <linux-unionfs@vger.kernel.org>
Subject: Re: Can ovl_drop_write() be called earlier in ovl_dentry_open()
Date: Mon, 01 Jun 2015 16:45:03 +0100 [thread overview]
Message-ID: <16823.1433173503@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAJfpegsuVxOAGenfxeSsQEKZR+_+OfR6uOxm2USGvbAuCWRhvg@mail.gmail.com>
Miklos Szeredi <miklos@szeredi.hu> wrote:
> > In ovl_dentry_open(), ovl_drop_write() is called after vfs_open() - but is
> > this actually necessary? Can't we just drop it post-copyup? After all,
> > that's all we wanted the write lock for, right?
>
> Hmm, that could result in a race where remount r/o of upper fs comes
> in between copy-up and vfs_open() so copy-up succeeds but the actual
> open fails. It's harmless, though, and not very likely. So I guess
> your patch is OK.
That race is there anyway if there's no copy up, right?
David
next prev parent reply other threads:[~2015-06-01 15:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-01 13:52 Can ovl_drop_write() be called earlier in ovl_dentry_open() David Howells
2015-06-01 14:21 ` [PATCH] overlay: Call ovl_drop_write() " David Howells
2015-06-01 14:22 ` Can ovl_drop_write() be called " Miklos Szeredi
2015-06-01 15:45 ` David Howells [this message]
2015-06-01 15:51 ` Miklos Szeredi
2015-06-01 15:53 ` David Howells
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