From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: [PATCH v3 003/110] ovl: rearrange ovl_follow_link to it doesn't need to call ->put_link Date: Mon, 11 May 2015 19:06:23 +0100 Message-ID: <1431367690-5223-3-git-send-email-viro@ZenIV.linux.org.uk> References: <20150511180650.GA4147@ZenIV.linux.org.uk> Cc: Neil Brown , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Linus Torvalds Return-path: In-Reply-To: <20150511180650.GA4147@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org From: NeilBrown ovl_follow_link current calls ->put_link on an error path. However ->put_link is about to change in a way that it will be impossible to call it from ovl_follow_link. So rearrange the code to avoid the need for that error path. Specifically: move the kmalloc() call before the ->follow_link() call to the subordinate filesystem. Signed-off-by: NeilBrown Signed-off-by: Al Viro --- fs/overlayfs/inode.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 04f1248..1b4b9c5e 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -145,6 +145,7 @@ static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd) void *ret; struct dentry *realdentry; struct inode *realinode; + struct ovl_link_data *data = NULL; realdentry = ovl_dentry_real(dentry); realinode = realdentry->d_inode; @@ -152,25 +153,23 @@ static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd) if (WARN_ON(!realinode->i_op->follow_link)) return ERR_PTR(-EPERM); - ret = realinode->i_op->follow_link(realdentry, nd); - if (IS_ERR(ret)) - return ret; - if (realinode->i_op->put_link) { - struct ovl_link_data *data; - data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL); - if (!data) { - realinode->i_op->put_link(realdentry, nd, ret); + if (!data) return ERR_PTR(-ENOMEM); - } data->realdentry = realdentry; - data->cookie = ret; + } - return data; - } else { - return NULL; + ret = realinode->i_op->follow_link(realdentry, nd); + if (IS_ERR(ret)) { + kfree(data); + return ret; } + + if (data) + data->cookie = ret; + + return data; } static void ovl_put_link(struct dentry *dentry, struct nameidata *nd, void *c) -- 2.1.4