Commit 9158e9e1 authored by Peng Tao's avatar Peng Tao Committed by Luis Henriques

nfs: fix dio deadlock when O_DIRECT flag is flipped

commit ee8a1a8b upstream.

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: default avatarPeng Tao <tao.peng@primarydata.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 6a06b937
......@@ -214,6 +214,12 @@ 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);
......
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