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authorPeng Tao <tao.peng@primarydata.com>2015-01-20 07:44:29 +0800
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-01-21 17:10:08 -0500
commitee8a1a8b160a87dc3a9c81a86796aa4db85ea815 (patch)
tree2e79c30b8263d64614e392708d1cadee09014638
parentec6f34e5b552fb0a52e6aae1a5afbbb1605cc6cc (diff)
downloadlinux-ee8a1a8b160a87dc3a9c81a86796aa4db85ea815.tar.bz2
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>
-rw-r--r--fs/nfs/direct.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 10bf07280f4a..294692ff83b1 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);