Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / fs / jffs2 / symlink.c

diff --git a/fs/jffs2/symlink.c b/fs/jffs2/symlink.c
index 7b1820d..d55754f 100644 (file)
--- a/fs/jffs2/symlink.c
+++ b/fs/jffs2/symlink.c
@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: symlink.c,v 1.14 2004/11/16 20:36:12 dwmw2 Exp $
+ * $Id: symlink.c,v 1.19 2005/11/07 11:14:42 gleixner Exp $
  *
  */
 
@@ -18,28 +18,46 @@
 #include <linux/namei.h>
 #include "nodelist.h"
 
-static int jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
-static void jffs2_put_link(struct dentry *dentry, struct nameidata *nd);
+static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
 
 struct inode_operations jffs2_symlink_inode_operations =
-{      
+{
        .readlink =     generic_readlink,
        .follow_link =  jffs2_follow_link,
-       .put_link =     jffs2_put_link,
        .setattr =      jffs2_setattr
 };
 
-static int jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
+static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
-       unsigned char *buf;
-       buf = jffs2_getlink(JFFS2_SB_INFO(dentry->d_inode->i_sb), JFFS2_INODE_INFO(dentry->d_inode));
-       nd_set_link(nd, buf);
-       return 0;
-}
+       struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
+       char *p = (char *)f->target;
 
-static void jffs2_put_link(struct dentry *dentry, struct nameidata *nd)
-{
-       char *s = nd_get_link(nd);
-       if (!IS_ERR(s))
-               kfree(s);
+       /*
+        * 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) {
+               printk(KERN_ERR "jffs2_follow_link(): can't find symlink taerget\n");
+               p = ERR_PTR(-EIO);
+       }
+       D1(printk(KERN_DEBUG "jffs2_follow_link(): target path is '%s'\n", (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;
 }
+