nfs: fix dio deadlock when O_DIRECT flag is flipped
authorPeng Tao <tao.peng@primarydata.com>
Mon, 19 Jan 2015 23:44:29 +0000 (07:44 +0800)
committerTrond Myklebust <trond.myklebust@primarydata.com>
Wed, 21 Jan 2015 22:10:08 +0000 (17:10 -0500)
commitee8a1a8b160a87dc3a9c81a86796aa4db85ea815
tree2e79c30b8263d64614e392708d1cadee09014638
parentec6f34e5b552fb0a52e6aae1a5afbbb1605cc6cc
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>
fs/nfs/direct.c