From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: [PATCH v7 11/14] ovl: Set OVL_UPPERDATA flag during ovl_lookup() Date: Thu, 16 Nov 2017 17:03:32 -0500 Message-ID: <20171116220335.13448-12-vgoyal@redhat.com> References: <20171116220335.13448-1-vgoyal@redhat.com> Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46778 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936129AbdKPWDp (ORCPT ); Thu, 16 Nov 2017 17:03:45 -0500 In-Reply-To: <20171116220335.13448-1-vgoyal@redhat.com> Sender: linux-unionfs-owner@vger.kernel.org List-Id: linux-unionfs@vger.kernel.org To: linux-unionfs@vger.kernel.org Cc: vgoyal@redhat.com, amir73il@gmail.com, miklos@szeredi.hu During lookup, check for presence of OVL_XATTR_METACOPY and if not present, set OVL_UPPERDATA bit in flags. This is only done for upper inode with a corresponding lower dentry and file needs to be a regular file. Basically any file which is eligible for metadata only copy up. Signed-off-by: Vivek Goyal --- fs/overlayfs/namei.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 625ed8066570..00f3ca8a3e58 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -25,6 +25,28 @@ struct ovl_lookup_data { char *redirect; }; +/* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */ +static int ovl_check_metacopy(struct dentry *dentry) +{ + int res; + + /* Only regular files can have metacopy xattr */ + if (!S_ISREG(d_inode(dentry)->i_mode)) + return 0; + + res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0); + if (res < 0) { + if (res == -ENODATA || res == -EOPNOTSUPP) + return 0; + goto out; + } + + return 1; +out: + pr_warn_ratelimited("overlayfs: failed to get metacopy (%i)\n", res); + return res; +} + static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d, size_t prelen, const char *post) { @@ -602,6 +624,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, struct dentry *this; unsigned int i; int err; + bool metacopy = false; struct ovl_lookup_data d = { .name = dentry->d_name, .is_dir = false, @@ -642,6 +665,20 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, roe->numlower, &stack, &ctr); if (err) goto out_put_upper; + + err = ovl_check_metacopy(upperdentry); + metacopy = err; + if (err < 0) + goto out_put_upper; + if (metacopy && !ctr) { + /* + * Found an upper with metacopy set but + * at the same time there is no lower + * dentry. Something is not right. + */ + err = -ESTALE; + goto out_put_upper; + } } if (d.redirect) { @@ -726,6 +763,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, OVL_I(inode)->redirect = upperredirect; if (index) ovl_set_flag(OVL_INDEX, inode); + + if (upperdentry && !metacopy) + ovl_set_flag(OVL_UPPERDATA, inode); } revert_creds(old_cred); -- 2.13.6