From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
hch@infradead.org, Trond.Myklebust@netapp.com
Subject: Re: [PATCH 1/2] vfs: dcache: fix deadlock in tree traversal
Date: Mon, 17 Sep 2012 15:09:39 -0700 [thread overview]
Message-ID: <CA+55aFxeghUVxiFS=P+ck_BCnOuMm=HFAkqTBccxJoubk96afQ@mail.gmail.com> (raw)
In-Reply-To: <20120917203946.GV13973@ZenIV.linux.org.uk>
On Mon, Sep 17, 2012 at 1:39 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> Egads... The problem is real and analysis, AFAICS, is correct, but result
> is extremely ugly ;-/
Agreed.
The problem (or at least one *part* of the problem) is that the "goto
rename_retry" case is done for two different entities entirely:
- the "try_to_ascend()" failure path, which can happen even when
renamelock is held for writing.
- the "if we weren't write-locked before, and the read-lock failed"
case (which obviously cannot happen if we already held things for
writing)
That said, I'm not sure why/how that try_to_ascend() could even fail
when we're holding things locked. I guess it's the DCACHE_DISCONNECTED
case that triggers.
So I'll ignore this series for now, hoping that Al will send a nicer
version. Al, Miklos, please make sure this issue doesn't get dropped
by mistake.
Linus
next prev parent reply other threads:[~2012-09-17 22:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-17 20:23 [PATCH 1/2] vfs: dcache: fix deadlock in tree traversal Miklos Szeredi
2012-09-17 20:31 ` [PATCH 2/2] vfs: dcache: use DCACHE_DENTRY_KILLED instead of DCACHE_DISCONNECTED in d_kill() Miklos Szeredi
2012-09-17 20:39 ` [PATCH 1/2] vfs: dcache: fix deadlock in tree traversal Al Viro
2012-09-17 22:09 ` Linus Torvalds [this message]
2012-09-18 14:53 ` Miklos Szeredi
2012-09-18 15:56 ` Linus Torvalds
2012-09-18 16:27 ` Miklos Szeredi
2012-09-18 18:22 ` Linus Torvalds
2012-09-18 20:35 ` [PATCH] trivial select_parent documentation fix J. Bruce Fields
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