Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / jffs2 / symlink.c

diff --git a/kernel/fs/jffs2/symlink.c b/kernel/fs/jffs2/symlink.c
new file mode 100644 (file)
index 0000000..1fefa25
--- /dev/null
+++ b/kernel/fs/jffs2/symlink.c
@@ -0,0 +1,66 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2001-2007 Red Hat, Inc.
+ *
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include "nodelist.h"
+
+static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
+
+const struct inode_operations jffs2_symlink_inode_operations =
+{
+       .readlink =     generic_readlink,
+       .follow_link =  jffs2_follow_link,
+       .setattr =      jffs2_setattr,
+       .setxattr =     jffs2_setxattr,
+       .getxattr =     jffs2_getxattr,
+       .listxattr =    jffs2_listxattr,
+       .removexattr =  jffs2_removexattr
+};
+
+static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       struct jffs2_inode_info *f = JFFS2_INODE_INFO(d_inode(dentry));
+       char *p = (char *)f->target;
+
+       /*
+        * We don't acquire the f->sem mutex here since the only data we
+        * use is f->target.
+        *
+        * 1. If we are here the inode has already built and f->target has
+        * to point to the target path.
+        * 2. Nobody uses f->target (if the inode is symlink's inode). The
+        * exception is inode freeing function which frees f->target. But
+        * it can't be called while we are here and before VFS has
+        * stopped using our f->target string which we provide by means of
+        * nd_set_link() call.
+        */
+
+       if (!p) {
+               pr_err("%s(): can't find symlink target\n", __func__);
+               p = ERR_PTR(-EIO);
+       }
+       jffs2_dbg(1, "%s(): target path is '%s'\n",
+                 __func__, (char *)f->target);
+
+       nd_set_link(nd, p);
+
+       /*
+        * We will unlock the f->sem mutex but VFS will use the f->target string. This is safe
+        * since the only way that may cause f->target to be changed is iput() operation.
+        * But VFS will not use f->target after iput() has been called.
+        */
+       return NULL;
+}
+