CIFS: Implement cifs_strict_writev (try #4)

If we don't have Exclusive oplock we write a data to the server.
Also set invalidate_mapping flag on the inode if we wrote something
to the server. Add cifs_iovec_write to let the client write iovec
buffers through CIFSSMBWrite2.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index a8323f1..f297013 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -600,10 +600,17 @@
 {
 	struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
 	ssize_t written;
+	int rc;
 
 	written = generic_file_aio_write(iocb, iov, nr_segs, pos);
-	if (!CIFS_I(inode)->clientCanCacheAll)
-		filemap_fdatawrite(inode->i_mapping);
+
+	if (CIFS_I(inode)->clientCanCacheAll)
+		return written;
+
+	rc = filemap_fdatawrite(inode->i_mapping);
+	if (rc)
+		cFYI(1, "cifs_file_aio_write: %d rc on %p inode", rc, inode);
+
 	return written;
 }
 
@@ -737,7 +744,7 @@
 	.read = do_sync_read,
 	.write = do_sync_write,
 	.aio_read = cifs_strict_readv,
-	.aio_write = cifs_file_aio_write,
+	.aio_write = cifs_strict_writev,
 	.open = cifs_open,
 	.release = cifs_close,
 	.lock = cifs_lock,
@@ -793,7 +800,7 @@
 	.read = do_sync_read,
 	.write = do_sync_write,
 	.aio_read = cifs_strict_readv,
-	.aio_write = cifs_file_aio_write,
+	.aio_write = cifs_strict_writev,
 	.open = cifs_open,
 	.release = cifs_close,
 	.fsync = cifs_strict_fsync,