Merge branch 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin

* 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: (57 commits)
  fs: scale mntget/mntput
  fs: rename vfsmount counter helpers
  fs: implement faster dentry memcmp
  fs: prefetch inode data in dcache lookup
  fs: improve scalability of pseudo filesystems
  fs: dcache per-inode inode alias locking
  fs: dcache per-bucket dcache hash locking
  bit_spinlock: add required includes
  kernel: add bl_list
  xfs: provide simple rcu-walk ACL implementation
  btrfs: provide simple rcu-walk ACL implementation
  ext2,3,4: provide simple rcu-walk ACL implementation
  fs: provide simple rcu-walk generic_check_acl implementation
  fs: provide rcu-walk aware permission i_ops
  fs: rcu-walk aware d_revalidate method
  fs: cache optimise dentry and inode for rcu-walk
  fs: dcache reduce branches in lookup path
  fs: dcache remove d_mounted
  fs: fs_struct use seqlock
  fs: rcu-walk for path lookup
  ...

1 files changed, 13 insertions, 8 deletions

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 2222d161c7b6..6ae2c8cac9d5 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -185,18 +185,23 @@ static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
         return ret;
 }
 
-int btrfs_check_acl(struct inode *inode, int mask)
+int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags)
 {
-        struct posix_acl *acl;
         int error = -EAGAIN;
 
-        acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+        if (flags & IPERM_FLAG_RCU) {
+                if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+                        error = -ECHILD;
 
-        if (IS_ERR(acl))
-                return PTR_ERR(acl);
-        if (acl) {
-                error = posix_acl_permission(inode, acl, mask);
-                posix_acl_release(acl);
+        } else {
+                struct posix_acl *acl;
+                acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+                if (IS_ERR(acl))
+                        return PTR_ERR(acl);
+                if (acl) {
+                        error = posix_acl_permission(inode, acl, mask);
+                        posix_acl_release(acl);
+                }
         }
 
         return error;