tree 2e79c30b8263d64614e392708d1cadee09014638
parent ec6f34e5b552fb0a52e6aae1a5afbbb1605cc6cc
author Peng Tao <tao.peng@primarydata.com> 1421711069 +0800
committer Trond Myklebust <trond.myklebust@primarydata.com> 1421878208 -0500

nfs: fix dio deadlock when O_DIRECT flag is flipped

We only support swap file calling nfs_direct_IO. However, application
might be able to get to nfs_direct_IO if it toggles O_DIRECT flag
during IO and it can deadlock because we grab inode->i_mutex in
nfs_file_direct_write(). So return 0 for such case. Then the generic
layer will fall back to buffer IO.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>