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From: Al Viro <viro@ftp.linux.org.uk>
To: Joshua Hudson <joshudson@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Possible deadlock in vfs layer, namei.c
Date: Thu, 2 Mar 2006 02:54:06 +0000	[thread overview]
Message-ID: <20060302025406.GV27946@ftp.linux.org.uk> (raw)
In-Reply-To: <bda6d13a0603011846s6bfed498ha9fb78c4ba74963c@mail.gmail.com>

On Wed, Mar 01, 2006 at 06:46:42PM -0800, Joshua Hudson wrote:
> I've been hunting down various deadlocks caused by hard links to directories.
> I found one that can happen *without* such things.
 
> process 1 does: rename("dir/subdir/file", "dir/file")
> process 2 does: rmdir("dir/subdir")
> 
> from namei.c (function: lock_rename), rename takes:
> 1. s_vfs_rename_sem,
> 2. dir/subdir: p1->d_inode->i_sem
> 3. dir: p2->d_inode->i_sem

No, it doesn't.  Wrong order - it will take dir before dir/subdir.
RTFM - Documentation/filesystems/directory-locking is there for
purpose.

  reply	other threads:[~2006-03-02  2:54 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-02  2:46 Possible deadlock in vfs layer, namei.c Joshua Hudson
2006-03-02  2:54 ` Al Viro [this message]
     [not found]   ` <bda6d13a0603011901x4b54c5a5jfed30f5fc629a3e@mail.gmail.com>
2006-03-02  3:22     ` Fwd: " Joshua Hudson

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