xfs: provide simple rcu-walk ACL implementation

This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c
index 4b11eaf6a580926befe9d9433f93f68bae5b2f82..39f4f809bb6807fa6f19b3b3e9f94b0189db60d0 100644 (file)
--- a/fs/xfs/linux-2.6/xfs_acl.c
+++ b/fs/xfs/linux-2.6/xfs_acl.c
@@ -225,9 +225,6 @@ xfs_check_acl(struct inode *inode, int mask, unsigned int flags)
        struct posix_acl *acl;
        int error = -EAGAIN;
 
-       if (flags & IPERM_FLAG_RCU)
-               return -ECHILD;
-
        ip = XFS_I(inode);
        trace_xfs_check_acl(ip);
 
@@ -238,6 +235,12 @@ xfs_check_acl(struct inode *inode, int mask, unsigned int flags)
        if (!XFS_IFORK_Q(ip))
                return -EAGAIN;
 
+       if (flags & IPERM_FLAG_RCU) {
+               if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+                       return -ECHILD;
+               return -EAGAIN;
+       }
+
        acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
        if (IS_ERR(acl))
                return PTR_ERR(acl);