Fix nasty ncpfs symlink handling bug.

[linux-2.6] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index b85f158aef0c8509867693a8c705e19f50fd6b1a..6ec1f0fefc5b017aa321738f7d3581370a91fad3 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -501,6 +501,7 @@ struct path {
 static inline int __do_follow_link(struct path *path, struct nameidata *nd)
 {
        int error;
+       void *cookie;
        struct dentry *dentry = path->dentry;
 
        touch_atime(path->mnt, dentry);
@@ -508,13 +509,15 @@ static inline int __do_follow_link(struct path *path, struct nameidata *nd)
 
        if (path->mnt == nd->mnt)
                mntget(path->mnt);
-       error = dentry->d_inode->i_op->follow_link(dentry, nd);
-       if (!error) {
+       cookie = dentry->d_inode->i_op->follow_link(dentry, nd);
+       error = PTR_ERR(cookie);
+       if (!IS_ERR(cookie)) {
                char *s = nd_get_link(nd);
+               error = 0;
                if (s)
                        error = __vfs_follow_link(nd, s);
                if (dentry->d_inode->i_op->put_link)
-                       dentry->d_inode->i_op->put_link(dentry, nd);
+                       dentry->d_inode->i_op->put_link(dentry, nd, cookie);
        }
        dput(dentry);
        mntput(path->mnt);
@@ -2344,15 +2347,17 @@ out:
 int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
        struct nameidata nd;
-       int res;
+       void *cookie;
+
        nd.depth = 0;
-       res = dentry->d_inode->i_op->follow_link(dentry, &nd);
-       if (!res) {
-               res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
+       cookie = dentry->d_inode->i_op->follow_link(dentry, &nd);
+       if (!IS_ERR(cookie)) {
+               int res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
                if (dentry->d_inode->i_op->put_link)
-                       dentry->d_inode->i_op->put_link(dentry, &nd);
+                       dentry->d_inode->i_op->put_link(dentry, &nd, cookie);
+               cookie = ERR_PTR(res);
        }
-       return res;
+       return PTR_ERR(cookie);
 }
 
 int vfs_follow_link(struct nameidata *nd, const char *link)
@@ -2395,23 +2400,20 @@ int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
        return res;
 }
 
-int page_follow_link_light(struct dentry *dentry, struct nameidata *nd)
+void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd)
 {
-       struct page *page;
+       struct page *page = NULL;
        nd_set_link(nd, page_getlink(dentry, &page));
-       return 0;
+       return page;
 }
 
-void page_put_link(struct dentry *dentry, struct nameidata *nd)
+void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 {
-       if (!IS_ERR(nd_get_link(nd))) {
-               struct page *page;
-               page = find_get_page(dentry->d_inode->i_mapping, 0);
-               if (!page)
-                       BUG();
+       struct page *page = cookie;
+
+       if (page) {
                kunmap(page);
                page_cache_release(page);
-               page_cache_release(page);
        }
 }