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authorPeng Tao <tao.peng@primarydata.com>2015-01-20 07:44:29 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-02-05 22:35:36 -0800
commit8e70c526add70fd1aad3b5c12c9ca56a8e7b63ef (patch)
tree615d108e1c5be2130e034277a645f8632dc08598 /fs/nfs
parentb15f0c0f6f989d3dd7b94db772c08d18350fd235 (diff)
downloadlinux-linaro-stable-8e70c526add70fd1aad3b5c12c9ca56a8e7b63ef.tar.gz
nfs: fix dio deadlock when O_DIRECT flag is flipped
commit ee8a1a8b160a87dc3a9c81a86796aa4db85ea815 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: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/nfs')
-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 725e87538c98..615c5079db7c 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -123,6 +123,12 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
*/
ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)
{
+ 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 (%s) off/no(%Ld/%lu) EINVAL\n",
iocb->ki_filp->f_path.dentry->d_name.name,