This is a note to let you know that I've just added the patch titled
nfs: fix dio deadlock when O_DIRECT flag is flipped
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfs-fix-dio-deadlock-when-o_direct-flag-is-flipped.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ee8a1a8b160a87dc3a9c81a86796aa4db85ea815 Mon Sep 17 00:00:00 2001
From: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
Date: Tue, 20 Jan 2015 07:44:29 +0800
Subject: nfs: fix dio deadlock when O_DIRECT flag is flipped
From: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/direct.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -123,6 +123,12 @@ static inline int put_dreq(struct nfs_di
*/
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,
Patches currently in stable-queue which might be from tao.peng@xxxxxxxxxxxxxxx are
queue-3.10/nfs-fix-dio-deadlock-when-o_direct-flag-is-flipped.patch
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