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Date: Thu, 29 May 2014 18:36:29 +0200
From: Miklos Szeredi <miklos@szeredi.hu>
To: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
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        ezk@fsl.cs.sunysb.edu, Sedat Dilek <sedat.dilek@gmail.com>,
        "J. R. Okajima" <hooanon05@yahoo.co.jp>,
        "mszeredi@suse.cz" <mszeredi@suse.cz>
Subject: Re: More kernel errors with overlay filesystem v22
Message-ID: <20140529163629.GN17233@tucsk.piliscsaba.szeredi.hu>
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On Thu, May 29, 2014 at 05:23:22PM +0100, David Howells wrote:
> Miklos Szeredi <miklos@szeredi.hu> wrote:
> 
> > Fixes pushed to overlayfs.v22 (and overlayfs.current).  Will
> > eventually fold these into the main overlayfs patch.
> 
> Okay... those are fixed.  Here's the next:
> 

generic_file_splice_write() uses I_MUTEX_CHILD.  Not sure why, though, parent
shouldn't be locked.  Maybe it's some remaining thing from the days when pipes
used the i_mutex on the pipe inode.  Probably should just remove that notation
and things will work.

Untested.

Thanks,
Miklos

diff --git a/fs/splice.c b/fs/splice.c
index fb1094bbe5af..3703c512c46e 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1019,7 +1019,7 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 		if (ret <= 0)
 			break;
 
-		mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
+		mutex_lock(&inode->i_mutex);
 		ret = file_remove_suid(out);
 		if (!ret) {
 			ret = file_update_time(out);