From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756704AbcLAKPW (ORCPT ); Thu, 1 Dec 2016 05:15:22 -0500 Received: from mail-wj0-f171.google.com ([209.85.210.171]:33539 "EHLO mail-wj0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756442AbcLAKPR (ORCPT ); Thu, 1 Dec 2016 05:15:17 -0500 From: Miklos Szeredi To: Al Viro Cc: linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 7/8] ovl: intercept fsync Date: Thu, 1 Dec 2016 11:15:02 +0100 Message-Id: <1480587303-25088-8-git-send-email-mszeredi@redhat.com> X-Mailer: git-send-email 2.5.5 In-Reply-To: <1480587303-25088-1-git-send-email-mszeredi@redhat.com> References: <1480587303-25088-1-git-send-email-mszeredi@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fsync is really an inode operation (AFAICS) so a doing it on a O_RDONLY file descriptor should flush any data written through an O_WRONLY file descriptor for example. To make this work correctly in case the file is copied up after being opened for read intercept the fsync fop, similarly to read_iter and mmap. Signed-off-by: Miklos Szeredi --- fs/overlayfs/inode.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 210838f97777..d861aa7462c5 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -412,6 +412,24 @@ static int ovl_mmap(struct file *file, struct vm_area_struct *vma) return file->f_op->mmap(file, vma); } +static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) +{ + int ret; + + if (likely(ovl_file_is_lower(file))) { + return OVL_CALL_REAL_FOP(file, + fsync(file, start, end, datasync)); + } + file = filp_clone_open(file); + if (IS_ERR(file)) + return PTR_ERR(file); + + ret = vfs_fsync_range(file, start, end, datasync); + fput(file); + + return ret; +} + static struct ovl_fops *ovl_fops_find(const struct file_operations *orig) { struct ovl_fops *ofop; @@ -455,9 +473,8 @@ static struct ovl_fops *ovl_fops_get(struct file *file) ofop->fops.read_iter = ovl_read_iter; if (orig->mmap) ofop->fops.mmap = ovl_mmap; - - /* These will need to be intercepted: */ - ofop->fops.fsync = orig->fsync; + if (orig->fsync) + ofop->fops.fsync = ovl_fsync; /* * These should be intercepted, but they are very unlikely to be -- 2.5.5