Return-Path: linux-nfs-owner@vger.kernel.org Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:55427 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751951AbaAQSTH (ORCPT ); Fri, 17 Jan 2014 13:19:07 -0500 Date: Fri, 17 Jan 2014 18:18:47 +0000 From: One Thousand Gnomes To: Pavel Shilovsky Cc: linux-kernel@vger.kernel.org, linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, wine-devel@winehq.org Subject: Re: [PATCH v7 1/7] VFS: Introduce new O_DENY* open flags Message-ID: <20140117181847.6c1f3831@alan.etchedpixels.co.uk> In-Reply-To: <1389953232-9428-2-git-send-email-piastry@etersoft.ru> References: <1389953232-9428-1-git-send-email-piastry@etersoft.ru> <1389953232-9428-2-git-send-email-piastry@etersoft.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: > +#define ESHAREDENIED 258 /* File is locked with a sharelock */ Have you prepared C library patches to match this ? (and why not just use EPERM, it has the meaning you want already) > + * Check to see if there's a share_reservation conflict. LOCK_READ/LOCK_WRITE > + * tell us whether the reservation allows other readers and writers. > + */ > +static int > +locks_mand_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) > +{ Shouldn't this also check for CAP_SYS_DAC or some similar permission so that root can override such a mess (eg to fix full disks in an emergency) ? > + > + /* > + * For sharelock mounts if a file was created but not opened, we need > + * to keep parent i_mutex until we finish the open to prevent races when > + * somebody opens newly created by us file and locks it with a sharelock > + * before we open it. > + */ > + if (IS_SHARELOCK(dir->d_inode) && error > 0 && *opened & FILE_CREATED) { > + /* Don't check for write permission, don't truncate */ > + open_flag &= ~O_TRUNC; > + will_truncate = false; > + acc_mode = MAY_OPEN; > + path_to_nameidata(path, nd); > + > + error = may_open(&nd->path, acc_mode, open_flag); > + if (error) { > + mutex_unlock(&dir->d_inode->i_mutex); > + goto out; > + } > + file->f_path.mnt = nd->path.mnt; > + error = finish_open(file, nd->path.dentry, NULL, opened); > + if (error) { > + mutex_unlock(&dir->d_inode->i_mutex); > + if (error == -EOPENSTALE) > + goto stale_open; > + goto out; > + } > + error = sharelock_lock_file(file); > + mutex_unlock(&dir->d_inode->i_mutex); > + if (error) > + goto exit_fput; > + goto opened; > + } > + > mutex_unlock(&dir->d_inode->i_mutex); What stops the file system changing mount flags via a remount between these two ? > > if (error <= 0) { > @@ -3034,6 +3073,18 @@ finish_open_created: > goto stale_open; > goto out; > } > + > + if (IS_SHARELOCK(dir->d_inode)) { > + /* > + * Lock parent i_mutex to prevent races with sharelocks on > + * newly created files. > + */ > + mutex_lock(&dir->d_inode->i_mutex); > + error = sharelock_lock_file(file); > + mutex_unlock(&dir->d_inode->i_mutex); > + if (error) > + goto exit_fput; > + } > opened: