fs: provide rcu-walk aware permission i_ops

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

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 223717dcc40..8e21e0fe65d 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -283,10 +283,13 @@ cifs_statfs(struct dentry *dentry, struct kstatfs *buf)
         return 0;
 }
 
-static int cifs_permission(struct inode *inode, int mask)
+static int cifs_permission(struct inode *inode, int mask, unsigned int flags)
 {
         struct cifs_sb_info *cifs_sb;
 
+        if (flags & IPERM_FLAG_RCU)
+                return -ECHILD;
+
         cifs_sb = CIFS_SB(inode->i_sb);
 
         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_PERM) {
@@ -298,7 +301,7 @@ static int cifs_permission(struct inode *inode, int mask)
                 on the client (above and beyond ACL on servers) for
                 servers which do not support setting and viewing mode bits,
                 so allowing client to check permissions is useful */
-                return generic_permission(inode, mask, NULL);
+                return generic_permission(inode, mask, flags, NULL);
 }
 
 static struct kmem_cache *cifs_inode_cachep;