ovl: store real inode pointer in ->i_private

[deliverable/linux.git] / fs / overlayfs / super.c

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 058103c60f54392e315a722011c0798683f65a63..313f773652fff87f2355bc02e09175a953b1acbb 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -145,25 +145,11 @@ struct dentry *ovl_dentry_real(struct dentry *dentry)
        return realdentry;
 }
 
-struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper)
+static void ovl_inode_init(struct inode *inode, struct inode *realinode,
+                          bool is_upper)
 {
-       struct dentry *realdentry;
-
-       realdentry = ovl_upperdentry_dereference(oe);
-       if (realdentry) {
-               *is_upper = true;
-       } else {
-               realdentry = __ovl_dentry_lower(oe);
-               *is_upper = false;
-       }
-       return realdentry;
-}
-
-struct inode *ovl_inode_real(struct inode *inode)
-{
-       bool tmp;
-
-       return d_inode(ovl_entry_real(inode->i_private, &tmp));
+       WRITE_ONCE(inode->i_private, (unsigned long) realinode |
+                  (is_upper ? OVL_ISUPPER_MASK : 0));
 }
 
 struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
@@ -235,7 +221,6 @@ void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
 
        WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
        WARN_ON(oe->__upperdentry);
-       BUG_ON(!upperdentry->d_inode);
        /*
         * Make sure upperdentry is consistent before making it visible to
         * ovl_upperdentry_dereference().
@@ -244,6 +229,13 @@ void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
        oe->__upperdentry = upperdentry;
 }
 
+void ovl_inode_update(struct inode *inode, struct inode *upperinode)
+{
+       WARN_ON(!upperinode);
+       WRITE_ONCE(inode->i_private,
+                  (unsigned long) upperinode | OVL_ISUPPER_MASK);
+}
+
 void ovl_dentry_version_inc(struct dentry *dentry)
 {
        struct ovl_entry *oe = dentry->d_fsdata;
@@ -574,14 +566,16 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 
        if (upperdentry || ctr) {
                struct dentry *realdentry;
+               struct inode *realinode;
 
                realdentry = upperdentry ? upperdentry : stack[0].dentry;
+               realinode = d_inode(realdentry);
 
                err = -ENOMEM;
-               inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode,
-                                     oe);
+               inode = ovl_new_inode(dentry->d_sb, realinode->i_mode);
                if (!inode)
                        goto out_free_oe;
+               ovl_inode_init(inode, realinode, !!upperdentry);
                ovl_copyattr(realdentry->d_inode, inode);
        }
 
@@ -969,6 +963,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
        struct path upperpath = { NULL, NULL };
        struct path workpath = { NULL, NULL };
        struct dentry *root_dentry;
+       struct inode *realinode;
        struct ovl_entry *oe;
        struct ovl_fs *ufs;
        struct path *stack = NULL;
@@ -1150,7 +1145,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
        if (!oe)
                goto out_put_cred;
 
-       root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe));
+       root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR));
        if (!root_dentry)
                goto out_free_oe;
 
@@ -1169,8 +1164,9 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
        root_dentry->d_fsdata = oe;
 
-       ovl_copyattr(ovl_dentry_real(root_dentry)->d_inode,
-                    root_dentry->d_inode);
+       realinode = d_inode(ovl_dentry_real(root_dentry));
+       ovl_inode_init(d_inode(root_dentry), realinode, !!upperpath.dentry);
+       ovl_copyattr(realinode, d_inode(root_dentry));
 
        sb->s_magic = OVERLAYFS_SUPER_MAGIC;
        sb->s_op = &ovl_super_operations;