From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Wed, 9 May 2012 18:30:35 +0000 (-0400)
Subject: NFS: Prevent a deadlock in the new writeback code
X-Git-Tag: v3.5-rc1~52^2~82
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3aff4ebb95b20ad8db2c1447e8c52097d89af5a7;p=pandora-kernel.git

NFS: Prevent a deadlock in the new writeback code

We have to unlock the nfs_page before we call nfs_end_page_writeback
to avoid races with functions that expect the page to be unlocked
when PG_locked and PG_writeback are not set.
The problem is that nfs_unlock_request also releases the nfs_page,
causing a deadlock if the release of the nfs_open_context
triggers an iput() while the PG_writeback flag is still set...

The solution is to separate the unlocking and release of the nfs_page,
so that we can do the former before nfs_end_page_writeback and the
latter after.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Fred Isaman <iisaman@netapp.com>
---

Reading git-diff-tree failed