CIFS: Fix write after setting a read lock for read oplock files

	struct cifsFileInfo *cfile = (struct cifsFileInfo *)

						iocb->ki_filp->private_data;

	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);

#ifdef CONFIG_CIFS_SMB2

	/*

	 * If we have an oplock for read and want to write a data to the file

	 * we need to store it in the page cache and then push it to the server

	 * to be sure the next read will get a valid data.

	 */

	if (!cinode->clientCanCacheAll && cinode->clientCanCacheRead) {

	ssize_t written;

		int rc;

		written = generic_file_aio_write(iocb, iov, nr_segs, pos);

		rc = filemap_fdatawrite(inode->i_mapping);

		if (rc)

			return (ssize_t)rc;

		return written;

	if (cinode->clientCanCacheAll) {

		if (cap_unix(tcon->ses) &&

		(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability))

		    && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))

			return generic_file_aio_write(iocb, iov, nr_segs, pos);

		return cifs_writev(iocb, iov, nr_segs, pos);

	}

#endif

	/*

	 * For non-oplocked files in strict cache mode we need to write the data

	 * to the server exactly from the pos to pos+len-1 rather than flush all

	 * affected pages because it may cause a error with mandatory locks on

	 * these pages but not on the region from pos to ppos+len-1.

	 */

	if (!cinode->clientCanCacheAll)

		return cifs_user_writev(iocb, iov, nr_segs, pos);

	if (cap_unix(tcon->ses) &&

	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&

	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))

		return generic_file_aio_write(iocb, iov, nr_segs, pos);

	return cifs_writev(iocb, iov, nr_segs, pos);

	written = cifs_user_writev(iocb, iov, nr_segs, pos);

	if (written > 0 && cinode->clientCanCacheRead) {

		/*

		 * Windows 7 server can delay breaking level2 oplock if a write

		 * request comes - break it on the client to prevent reading

		 * an old data.

		 */

		cifs_invalidate_mapping(inode);

		cFYI(1, "Set no oplock for inode=%p after a write operation",

		     inode);

		cinode->clientCanCacheRead = false;

	}

	return written;

}

static struct cifs_readdata *