RCUify freeing acls, let check_acl() go ahead in RCU mode if acl is cached

[pandora-kernel.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index f8c69d3..3d607bd 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -179,19 +179,14 @@ static int check_acl(struct inode *inode, int mask)
 #ifdef CONFIG_FS_POSIX_ACL
        struct posix_acl *acl;
 
-       /*
-        * Under RCU walk, we cannot even do a "get_cached_acl()",
-        * because that involves locking and getting a refcount on
-        * a cached ACL.
-        *
-        * So the only case we handle during RCU walking is the
-        * case of a cached "no ACL at all", which needs no locks
-        * or refcounts.
-        */
        if (mask & MAY_NOT_BLOCK) {
-               if (negative_cached_acl(inode, ACL_TYPE_ACCESS))
+               acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS);
+               if (!acl)
                        return -EAGAIN;
-               return -ECHILD;
+               /* no ->get_acl() calls in RCU mode... */
+               if (acl == ACL_NOT_CACHED)
+                       return -ECHILD;
+               return posix_acl_permission(inode, acl, mask);
        }
 
        acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
@@ -716,19 +711,25 @@ static int follow_automount(struct path *path, unsigned flags,
        if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_PARENT))
                return -EISDIR; /* we actually want to stop here */
 
-       /* We want to mount if someone is trying to open/create a file of any
-        * type under the mountpoint, wants to traverse through the mountpoint
-        * or wants to open the mounted directory.
-        *
+       /*
         * We don't want to mount if someone's just doing a stat and they've
         * set AT_SYMLINK_NOFOLLOW - unless they're stat'ing a directory and
         * appended a '/' to the name.
         */
-       if (!(flags & LOOKUP_FOLLOW) &&
-           !(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
-                      LOOKUP_OPEN | LOOKUP_CREATE)))
-               return -EISDIR;
-
+       if (!(flags & LOOKUP_FOLLOW)) {
+               /* We do, however, want to mount if someone wants to open or
+                * create a file of any type under the mountpoint, wants to
+                * traverse through the mountpoint or wants to open the mounted
+                * directory.
+                * Also, autofs may mark negative dentries as being automount
+                * points.  These will need the attentions of the daemon to
+                * instantiate them before they can be used.
+                */
+               if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
+                            LOOKUP_OPEN | LOOKUP_CREATE)) &&
+                   path->dentry->d_inode)
+                       return -EISDIR;
+       }
        current->total_link_count++;
        if (current->total_link_count >= 40)
                return -ELOOP;