| From | Jiri Slaby <> | Subject | [PATCH 3.12 041/122] nfs: fix dio deadlock when O_DIRECT flag is flipped | Date | Tue, 17 Feb 2015 12:33:48 +0100 |
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From: Peng Tao <tao.peng@primarydata.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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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: Jiri Slaby <jslaby@suse.cz> --- fs/nfs/direct.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index d751a2383c24..db6245c1cd33 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, -- 2.2.2
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