From: NeilBrown Date: Mon, 23 Mar 2015 02:37:39 +0000 (+1100) Subject: ovl: rearrange ovl_follow_link to it doesn't need to call ->put_link X-Git-Tag: firefly_0821_release~176^2~1459^2~158 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3188b2955de3d01949ec54eb2c9ff1ecaa0a752d;p=firefly-linux-kernel-4.4.55.git ovl: rearrange ovl_follow_link to it doesn't need to call ->put_link 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 --- diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 04f124884687..1b4b9c5e51b7 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)