From ee8a1a8b160a87dc3a9c81a86796aa4db85ea815 Mon Sep 17 00:00:00 2001 From: Peng Tao Date: Tue, 20 Jan 2015 07:44:29 +0800 Subject: [PATCH] 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 Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust --- fs/nfs/direct.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 10bf072..294692f 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -212,6 +212,12 @@ static int nfs_direct_cmp_commit_data_verf(struct nfs_direct_req *dreq, */ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos) { + struct inode *inode = iocb->ki_filp->f_mapping->host; + + /* we only support swap file calling nfs_direct_IO */ + if (!IS_SWAPFILE(inode)) + return 0; + #ifndef CONFIG_NFS_SWAP dprintk("NFS: nfs_direct_IO (%pD) off/no(%Ld/%lu) EINVAL\n", iocb->ki_filp, (long long) pos, iter->nr_segs); -- 2.7.4