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>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c
index 4b11eaf6a58..39f4f809bb6 100644
--- 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);