int cifs_open(struct inode *inode, struct file *file)

{
	int rc = -EACCES;
	unsigned int xid;
	__u32 oplock;
	struct cifs_sb_info *cifs_sb;
	struct TCP_Server_Info *server;
	struct cifs_tcon *tcon;
	struct tcon_link *tlink;
	struct cifsFileInfo *cfile = NULL;
	char *full_path = NULL;
	bool posix_open_ok = false;
	struct cifs_fid fid;
	struct cifs_pending_open open;

	xid = get_xid();

	cifs_sb = CIFS_SB(inode->i_sb);
	tlink = cifs_sb_tlink(cifs_sb);
	if (IS_ERR(tlink)) {
		free_xid(xid);
		return PTR_ERR(tlink);
	}
	tcon = tlink_tcon(tlink);
	server = tcon->ses->server;

	full_path = build_path_from_dentry(file->f_path.dentry);
	if (full_path == NULL) {
		rc = -ENOMEM;
		goto out;
	}

	cifs_dbg(FYI, "inode = 0x%p file flags are 0x%x for %s\n",
		 inode, file->f_flags, full_path);

	if (server->oplocks)
		oplock = REQ_OPLOCK;
	else
		oplock = 0;

	if (!tcon->broken_posix_open && tcon->unix_ext &&
	    cap_unix(tcon->ses) && (CIFS_UNIX_POSIX_PATH_OPS_CAP &
				le64_to_cpu(tcon->fsUnixInfo.Capability))) {
		/* can not refresh inode info since size could be stale */
		rc = cifs_posix_open(full_path, &inode, inode->i_sb,
				cifs_sb->mnt_file_mode /* ignored */,
				file->f_flags, &oplock, &fid.netfid, xid);
		if (rc == 0) {
			cifs_dbg(FYI, "posix open succeeded\n");
			posix_open_ok = true;
		} else if ((rc == -EINVAL) || (rc == -EOPNOTSUPP)) {
			if (tcon->ses->serverNOS)
				cifs_dbg(VFS, "server %s of type %s returned unexpected error on SMB posix open, disabling posix open support. Check if server update available.\n",
					 tcon->ses->serverName,
					 tcon->ses->serverNOS);
			tcon->broken_posix_open = true;
		} else if ((rc != -EIO) && (rc != -EREMOTE) &&
			 (rc != -EOPNOTSUPP)) /* path not found or net err */
			goto out;
		/*
		 * Else fallthrough to retry open the old way on network i/o
		 * or DFS errors.
		 */
	}

	if (server->ops->get_lease_key)
		server->ops->get_lease_key(inode, &fid);

	cifs_add_pending_open(&fid, tlink, &open);

	if (!posix_open_ok) {
		if (server->ops->get_lease_key)
			server->ops->get_lease_key(inode, &fid);

		rc = cifs_nt_open(full_path, inode, cifs_sb, tcon,
				  file->f_flags, &oplock, &fid, xid);
		if (rc) {
			cifs_del_pending_open(&open);
			goto out;
		}
	}

	cfile = cifs_new_fileinfo(&fid, file, tlink, oplock);
	if (cfile == NULL) {
		if (server->ops->close)
			server->ops->close(xid, tcon, &fid);
		cifs_del_pending_open(&open);
		rc = -ENOMEM;
		goto out;
	}

	cifs_fscache_set_inode_cookie(inode, file);

	if ((oplock & CIFS_CREATE_ACTION) && !posix_open_ok && tcon->unix_ext) {
		/*
		 * Time to set mode which we can not set earlier due to
		 * problems creating new read-only files.
		 */
		struct cifs_unix_set_info_args args = {
			.mode	= inode->i_mode,
			.uid	= INVALID_UID, /* no change */
			.gid	= INVALID_GID, /* no change */
			.ctime	= NO_CHANGE_64,
			.atime	= NO_CHANGE_64,
			.mtime	= NO_CHANGE_64,
			.device	= 0,
		};
		CIFSSMBUnixSetFileInfo(xid, tcon, &args, fid.netfid,
				       cfile->pid);
	}

out:
	kfree(full_path);
	free_xid(xid);
	cifs_put_tlink(tlink);
	return rc;
}
int cifs_open(struct inode *inode, struct file *file)

{
	int rc = -EACCES;
	unsigned int xid;
	__u32 oplock;
	struct cifs_sb_info *cifs_sb;
	struct TCP_Server_Info *server;
	struct cifs_tcon *tcon;
	struct tcon_link *tlink;
	struct cifsFileInfo *cfile = NULL;
	char *full_path = NULL;
	bool posix_open_ok = false;
	struct cifs_fid fid;
	struct cifs_pending_open open;

	xid = get_xid();

	cifs_sb = CIFS_SB(inode->i_sb);
	tlink = cifs_sb_tlink(cifs_sb);
	if (IS_ERR(tlink)) {
		free_xid(xid);
		return PTR_ERR(tlink);
	}
	tcon = tlink_tcon(tlink);
	server = tcon->ses->server;

	full_path = build_path_from_dentry(file->f_path.dentry);
	if (full_path == NULL) {
		rc = -ENOMEM;
		goto out;
	}

	cifs_dbg(FYI, "inode = 0x%p file flags are 0x%x for %s\n",
		 inode, file->f_flags, full_path);

	if (server->oplocks)
		oplock = REQ_OPLOCK;
	else
		oplock = 0;

	if (!tcon->broken_posix_open && tcon->unix_ext &&
	    cap_unix(tcon->ses) && (CIFS_UNIX_POSIX_PATH_OPS_CAP &
				le64_to_cpu(tcon->fsUnixInfo.Capability))) {
		 
		rc = cifs_posix_open(full_path, &inode, inode->i_sb,
				cifs_sb->mnt_file_mode  ,
				file->f_flags, &oplock, &fid.netfid, xid);
		if (rc == 0) {
			cifs_dbg(FYI, "posix open succeeded\n");
			posix_open_ok = true;
		} else if ((rc == -EINVAL) || (rc == -EOPNOTSUPP)) {
			if (tcon->ses->serverNOS)
				cifs_dbg(VFS, "server %s of type %s returned unexpected error on SMB posix open, disabling posix open support. Check if server update available.\n",
					 tcon->ses->serverName,
					 tcon->ses->serverNOS);
			tcon->broken_posix_open = true;
		} else if ((rc != -EIO) && (rc != -EREMOTE) &&
			 (rc != -EOPNOTSUPP))  
			goto out;
		 
	}

	if (server->ops->get_lease_key)
		server->ops->get_lease_key(inode, &fid);

	cifs_add_pending_open(&fid, tlink, &open);

	if (!posix_open_ok) {
		if (server->ops->get_lease_key)
			server->ops->get_lease_key(inode, &fid);

		rc = cifs_nt_open(full_path, inode, cifs_sb, tcon,
				  file->f_flags, &oplock, &fid, xid);
		if (rc) {
			cifs_del_pending_open(&open);
			goto out;
		}
	}

	cfile = cifs_new_fileinfo(&fid, file, tlink, oplock);
	if (cfile == NULL) {
		if (server->ops->close)
			server->ops->close(xid, tcon, &fid);
		cifs_del_pending_open(&open);
		rc = -ENOMEM;
		goto out;
	}

	cifs_fscache_set_inode_cookie(inode, file);

	if ((oplock & CIFS_CREATE_ACTION) && !posix_open_ok && tcon->unix_ext) {
		 
		struct cifs_unix_set_info_args args = {
			.mode	= inode->i_mode,
			.uid	= INVALID_UID,  
			.gid	= INVALID_GID,  
			.ctime	= NO_CHANGE_64,
			.atime	= NO_CHANGE_64,
			.mtime	= NO_CHANGE_64,
			.device	= 0,
		};
		CIFSSMBUnixSetFileInfo(xid, tcon, &args, fid.netfid,
				       cfile->pid);
	}

out:
	kfree(full_path);
	free_xid(xid);
	cifs_put_tlink(tlink);
	return rc;
}