namei: add audit_inode to all branches in path_lookup

Main change is in path_lookup: added a goto to do audit_inode
instead of return statement, when emul_lookup_dentry for root
is successful.The existing code does audit_inode only when
lookup is done in normal root or cwd.

Other changes: Some lookup routines are returning zero on success,
and some are returning zero on failure. I documented the related
function signatures in this code path, so that one can glance over
abstract functions without understanding the entire code.

Signed-off-by: Prasanna Meda <pmeda@akamai.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

diff --git a/fs/namei.c b/fs/namei.c
index 9e4aef2a1a21d44a9ba54b00f5ac284dd590f331..0f76fd75591bd0d5c3fbf44a2540519a972a44a2 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -686,11 +686,11 @@ fail:
 
 /*
  * Name resolution.
+ * This is the basic name resolution function, turning a pathname into
+ * the final dentry. We expect 'base' to be positive and a directory.
  *
- * This is the basic name resolution function, turning a pathname
- * into the final dentry.
- *
- * We expect 'base' to be positive and a directory.
+ * Returns 0 and nd will have valid dentry and mnt on success.
+ * Returns error and drops reference to input namei data on failure.
  */
 static fastcall int __link_path_walk(const char * name, struct nameidata *nd)
 {
@@ -929,8 +929,10 @@ int fastcall path_walk(const char * name, struct nameidata *nd)
        return link_path_walk(name, nd);
 }
 
-/* SMP-safe */
-/* returns 1 if everything is done */
+/* 
+ * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if
+ * everything is done. Returns 0 and drops input nd, if lookup failed;
+ */
 static int __emul_lookup_dentry(const char *name, struct nameidata *nd)
 {
        if (path_walk(name, nd))
@@ -994,9 +996,10 @@ set_it:
        }
 }
 
+/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
 int fastcall path_lookup(const char *name, unsigned int flags, struct nameidata *nd)
 {
-       int retval;
+       int retval = 0;
 
        nd->last_type = LAST_ROOT; /* if there are only slashes... */
        nd->flags = flags;
@@ -1009,7 +1012,7 @@ int fastcall path_lookup(const char *name, unsigned int flags, struct nameidata
                        nd->dentry = dget(current->fs->altroot);
                        read_unlock(&current->fs->lock);
                        if (__emul_lookup_dentry(name,nd))
-                               return 0;
+                               goto out; /* found in altroot */
                        read_lock(&current->fs->lock);
                }
                nd->mnt = mntget(current->fs->rootmnt);
@@ -1021,6 +1024,7 @@ int fastcall path_lookup(const char *name, unsigned int flags, struct nameidata
        read_unlock(&current->fs->lock);
        current->total_link_count = 0;
        retval = link_path_walk(name, nd);
+out:
        if (unlikely(current->audit_context
                     && nd && nd->dentry && nd->dentry->d_inode))
                audit_inode(name, nd->dentry->d_inode);