fuse: add flag to turn on async direct IO

Without async DIO write requests to a single file were always serialized.
With async DIO that's no longer the case.

So don't turn on async DIO by default for fear of breaking backward
compatibility.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 1f8e3d60dc07..6ab7ca43f9e0 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2371,14 +2371,14 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
                         loff_t offset, unsigned long nr_segs)
 {
         ssize_t ret = 0;
-        struct file *file = NULL;
+        struct file *file = iocb->ki_filp;
+        struct fuse_file *ff = file->private_data;
         loff_t pos = 0;
         struct inode *inode;
         loff_t i_size;
         size_t count = iov_length(iov, nr_segs);
         struct fuse_io_priv *io;
 
-        file = iocb->ki_filp;
         pos = offset;
         inode = file->f_mapping->host;
         i_size = i_size_read(inode);
@@ -2403,9 +2403,9 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
         io->file = file;
         /*
          * By default, we want to optimize all I/Os with async request
-         * submission to the client filesystem.
+         * submission to the client filesystem if supported.
          */
-        io->async = 1;
+        io->async = ff->fc->async_dio;
         io->iocb = iocb;
 
         /*