ovl: move __upperdentry to ovl_inode

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/copy_up.c

@@ -417,8 +417,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
 		goto out_cleanup;
 
 	newdentry = dget(tmpfile ? upper : temp);
-	ovl_dentry_update(dentry, newdentry);
-	ovl_inode_update(d_inode(dentry), d_inode(newdentry));
+	ovl_inode_update(d_inode(dentry), newdentry);
 
 	/* Restore timestamps on parent (best effort) */
 	ovl_set_timestamps(upperdir, pstat);

fs/overlayfs/dir.c

@@ -154,12 +154,12 @@ static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
 			    struct dentry *newdentry, bool hardlink)
 {
 	ovl_dentry_version_inc(dentry->d_parent);
-	ovl_dentry_update(dentry, newdentry);
 	if (!hardlink) {
-		ovl_inode_update(inode, d_inode(newdentry));
+		ovl_inode_update(inode, newdentry);
 		ovl_copyattr(newdentry->d_inode, inode);
 	} else {
-		WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry));
+		WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));
+		dput(newdentry);
 		inc_nlink(inode);
 	}
 	d_instantiate(dentry, inode);
@@ -1003,7 +1003,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
 	new_opaque = ovl_dentry_is_opaque(new);
 
 	err = -ESTALE;
-	if (ovl_dentry_upper(new)) {
+	if (d_inode(new) && ovl_dentry_upper(new)) {
 		if (opaquedir) {
 			if (newdentry != opaquedir)
 				goto out_dput;

fs/overlayfs/inode.c

@@ -134,8 +134,8 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
 
 int ovl_permission(struct inode *inode, int mask)
 {
-	bool is_upper;
-	struct inode *realinode = ovl_inode_real(inode, &is_upper);
+	struct inode *upperinode = ovl_inode_upper(inode);
+	struct inode *realinode = upperinode ?: ovl_inode_lower(inode);
 	const struct cred *old_cred;
 	int err;
 
@@ -154,7 +154,8 @@ int ovl_permission(struct inode *inode, int mask)
 		return err;
 
 	old_cred = ovl_override_creds(inode->i_sb);
-	if (!is_upper && !special_file(realinode->i_mode) && mask & MAY_WRITE) {
+	if (!upperinode &&
+	    !special_file(realinode->i_mode) && mask & MAY_WRITE) {
 		mask &= ~(MAY_WRITE | MAY_APPEND);
 		/* Make sure mounter can read file for copy up later */
 		mask |= MAY_READ;
@@ -286,7 +287,7 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 
 struct posix_acl *ovl_get_acl(struct inode *inode, int type)
 {
-	struct inode *realinode = ovl_inode_real(inode, NULL);
+	struct inode *realinode = ovl_inode_real(inode);
 	const struct cred *old_cred;
 	struct posix_acl *acl;
 
@@ -462,17 +463,24 @@ static int ovl_inode_set(struct inode *inode, void *data)
 	return 0;
 }
 
-struct inode *ovl_get_inode(struct dentry *dentry)
+struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry)
 {
-	struct dentry *upperdentry = ovl_dentry_upper(dentry);
-	struct inode *realinode = d_inode(ovl_dentry_real(dentry));
+	struct dentry *lowerdentry = ovl_dentry_lower(dentry);
+	struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL;
 	struct inode *inode;
 
+	if (!realinode)
+		realinode = d_inode(lowerdentry);
+
 	if (upperdentry && !d_is_dir(upperdentry)) {
 		inode = iget5_locked(dentry->d_sb, (unsigned long) realinode,
 				     ovl_inode_test, ovl_inode_set, realinode);
-		if (!inode || !(inode->i_state & I_NEW))
+		if (!inode)
 			goto out;
+		if (!(inode->i_state & I_NEW)) {
+			dput(upperdentry);
+			goto out;
+		}
 
 		set_nlink(inode, realinode->i_nlink);
 	} else {
@@ -481,7 +489,7 @@ struct inode *ovl_get_inode(struct dentry *dentry)
 			goto out;
 	}
 	ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev);
-	ovl_inode_init(inode, dentry);
+	ovl_inode_init(inode, upperdentry, lowerdentry);
 	if (inode->i_state & I_NEW)
 		unlock_new_inode(inode);
 out:

fs/overlayfs/namei.c

@@ -359,7 +359,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 		return ERR_PTR(-ENAMETOOLONG);
 
 	old_cred = ovl_override_creds(dentry->d_sb);
-	upperdir = ovl_upperdentry_dereference(poe);
+	upperdir = ovl_dentry_upper(dentry->d_parent);
 	if (upperdir) {
 		err = ovl_lookup_layer(upperdir, &d, &upperdentry);
 		if (err)
@@ -436,13 +436,12 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 	oe->opaque = upperopaque;
 	oe->impure = upperimpure;
 	oe->redirect = upperredirect;
-	oe->__upperdentry = upperdentry;
 	memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
 	dentry->d_fsdata = oe;
 
 	if (upperdentry || ctr) {
 		err = -ENOMEM;
-		inode = ovl_get_inode(dentry);
+		inode = ovl_get_inode(dentry, upperdentry);
 		if (!inode)
 			goto out_free_oe;
 	}
@@ -487,7 +486,7 @@ bool ovl_lower_positive(struct dentry *dentry)
 		return oe->opaque;
 
 	/* Negative upper -> positive lower */
-	if (!oe->__upperdentry)
+	if (!ovl_dentry_upper(dentry))
 		return true;
 
 	/* Positive upper -> have to look up lower to see whether it exists */

fs/overlayfs/overlayfs.h

@@ -189,7 +189,9 @@ enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 struct dentry *ovl_dentry_real(struct dentry *dentry);
-struct inode *ovl_inode_real(struct inode *inode, bool *is_upper);
+struct inode *ovl_inode_upper(struct inode *inode);
+struct inode *ovl_inode_lower(struct inode *inode);
+struct inode *ovl_inode_real(struct inode *inode);
 struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
 void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
 bool ovl_dentry_is_opaque(struct dentry *dentry);
@@ -199,9 +201,9 @@ void ovl_dentry_set_opaque(struct dentry *dentry);
 bool ovl_redirect_dir(struct super_block *sb);
 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
-void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
-void ovl_inode_init(struct inode *inode, struct dentry *dentry);
-void ovl_inode_update(struct inode *inode, struct inode *upperinode);
+void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
+		    struct dentry *lowerdentry);
+void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
 void ovl_dentry_version_inc(struct dentry *dentry);
 u64 ovl_dentry_version_get(struct dentry *dentry);
 bool ovl_is_whiteout(struct dentry *dentry);
@@ -250,7 +252,7 @@ int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
 bool ovl_is_private_xattr(const char *name);
 
 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
-struct inode *ovl_get_inode(struct dentry *dentry);
+struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry);
 static inline void ovl_copyattr(struct inode *from, struct inode *to)
 {
 	to->i_uid = from->i_uid;

fs/overlayfs/ovl_entry.h

@@ -36,7 +36,6 @@ struct ovl_fs {
 
 /* private information held for every overlayfs dentry */
 struct ovl_entry {
-	struct dentry *__upperdentry;
 	struct ovl_dir_cache *cache;
 	union {
 		struct {
@@ -54,14 +53,9 @@ struct ovl_entry {
 
 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
 
-static inline struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
-{
-	return lockless_dereference(oe->__upperdentry);
-}
-
 struct ovl_inode {
 	struct inode vfs_inode;
-	struct inode *upper;
+	struct dentry *__upperdentry;
 	struct inode *lower;
 };
 
@@ -69,3 +63,8 @@ static inline struct ovl_inode *OVL_I(struct inode *inode)
 {
 	return container_of(inode, struct ovl_inode, vfs_inode);
 }
+
+static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
+{
+	return lockless_dereference(oi->__upperdentry);
+}

fs/overlayfs/super.c

@@ -41,7 +41,6 @@ static void ovl_dentry_release(struct dentry *dentry)
 	if (oe) {
 		unsigned int i;
 
-		dput(oe->__upperdentry);
 		kfree(oe->redirect);
 		for (i = 0; i < oe->numlower; i++)
 			dput(oe->lowerstack[i].dentry);
@@ -171,7 +170,7 @@ static struct inode *ovl_alloc_inode(struct super_block *sb)
 {
 	struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL);
 
-	oi->upper = NULL;
+	oi->__upperdentry = NULL;
 	oi->lower = NULL;
 
 	return &oi->vfs_inode;
@@ -186,6 +185,10 @@ static void ovl_i_callback(struct rcu_head *head)
 
 static void ovl_destroy_inode(struct inode *inode)
 {
+	struct ovl_inode *oi = OVL_I(inode);
+
+	dput(oi->__upperdentry);
+
 	call_rcu(&inode->i_rcu, ovl_i_callback);
 }
 
@@ -636,7 +639,7 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 			size_t size, int flags)
 {
 	struct dentry *workdir = ovl_workdir(dentry);
-	struct inode *realinode = ovl_inode_real(inode, NULL);
+	struct inode *realinode = ovl_inode_real(inode);
 	struct posix_acl *acl = NULL;
 	int err;
 
@@ -678,7 +681,7 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 
 	err = ovl_xattr_set(dentry, handler->name, value, size, flags);
 	if (!err)
-		ovl_copyattr(ovl_inode_real(inode, NULL), inode);
+		ovl_copyattr(ovl_inode_real(inode), inode);
 
 	return err;
 
@@ -1000,7 +1003,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	kfree(lowertmp);
 
 	if (upperpath.dentry) {
-		oe->__upperdentry = upperpath.dentry;
 		oe->impure = ovl_is_impuredir(upperpath.dentry);
 	}
 	for (i = 0; i < numlower; i++) {
@@ -1011,7 +1013,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
 	root_dentry->d_fsdata = oe;
 
-	ovl_inode_init(d_inode(root_dentry), root_dentry);
+	ovl_inode_init(d_inode(root_dentry), upperpath.dentry,
+		       ovl_dentry_lower(root_dentry));
 
 	sb->s_root = root_dentry;
 

fs/overlayfs/util.c

@@ -78,7 +78,7 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry)
 	struct ovl_entry *oe = dentry->d_fsdata;
 	enum ovl_path_type type = 0;
 
-	if (oe->__upperdentry) {
+	if (ovl_dentry_upper(dentry)) {
 		type = __OVL_PATH_UPPER;
 
 		/*
@@ -99,10 +99,9 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry)
 void ovl_path_upper(struct dentry *dentry, struct path *path)
 {
 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
-	struct ovl_entry *oe = dentry->d_fsdata;
 
 	path->mnt = ofs->upper_mnt;
-	path->dentry = ovl_upperdentry_dereference(oe);
+	path->dentry = ovl_dentry_upper(dentry);
 }
 
 void ovl_path_lower(struct dentry *dentry, struct path *path)
@@ -126,51 +125,39 @@ enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
 
 struct dentry *ovl_dentry_upper(struct dentry *dentry)
 {
-	struct ovl_entry *oe = dentry->d_fsdata;
-
-	return ovl_upperdentry_dereference(oe);
-}
-
-static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
-{
-	return oe->numlower ? oe->lowerstack[0].dentry : NULL;
+	return ovl_upperdentry_dereference(OVL_I(d_inode(dentry)));
 }
 
 struct dentry *ovl_dentry_lower(struct dentry *dentry)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;
 
-	return __ovl_dentry_lower(oe);
+	return oe->numlower ? oe->lowerstack[0].dentry : NULL;
 }
 
 struct dentry *ovl_dentry_real(struct dentry *dentry)
 {
-	struct ovl_entry *oe = dentry->d_fsdata;
-	struct dentry *realdentry;
-
-	realdentry = ovl_upperdentry_dereference(oe);
-	if (!realdentry)
-		realdentry = __ovl_dentry_lower(oe);
-
-	return realdentry;
+	return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);
 }
 
-struct inode *ovl_inode_real(struct inode *inode, bool *is_upper)
+struct inode *ovl_inode_upper(struct inode *inode)
 {
-	struct inode *realinode = lockless_dereference(OVL_I(inode)->upper);
-	bool isup = false;
+	struct dentry *upperdentry = ovl_upperdentry_dereference(OVL_I(inode));
 
-	if (!realinode)
-		realinode = OVL_I(inode)->lower;
-	else
-		isup = true;
+	return upperdentry ? d_inode(upperdentry) : NULL;
+}
 
-	if (is_upper)
-		*is_upper = isup;
+struct inode *ovl_inode_lower(struct inode *inode)
+{
+	return OVL_I(inode)->lower;
+}
 
-	return realinode;
+struct inode *ovl_inode_real(struct inode *inode)
+{
+	return ovl_inode_upper(inode) ?: ovl_inode_lower(inode);
 }
 
+
 struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;
@@ -232,42 +219,30 @@ void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
 	oe->redirect = redirect;
 }
 
-void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
+void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
+		    struct dentry *lowerdentry)
 {
-	struct ovl_entry *oe = dentry->d_fsdata;
+	if (upperdentry)
+		OVL_I(inode)->__upperdentry = upperdentry;
+	if (lowerdentry)
+		OVL_I(inode)->lower = d_inode(lowerdentry);
 
-	WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
-	WARN_ON(oe->__upperdentry);
-	/*
-	 * Make sure upperdentry is consistent before making it visible to
-	 * ovl_upperdentry_dereference().
-	 */
-	smp_wmb();
-	oe->__upperdentry = upperdentry;
+	ovl_copyattr(d_inode(upperdentry ?: lowerdentry), inode);
 }
 
-void ovl_inode_init(struct inode *inode, struct dentry *dentry)
+void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
 {
-	struct inode *realinode = d_inode(ovl_dentry_real(dentry));
+	struct inode *upperinode = d_inode(upperdentry);
 
-	if (ovl_dentry_upper(dentry))
-		OVL_I(inode)->upper = realinode;
-	else
-		OVL_I(inode)->lower = realinode;
-
-	ovl_copyattr(realinode, inode);
-}
-
-void ovl_inode_update(struct inode *inode, struct inode *upperinode)
-{
-	WARN_ON(!upperinode);
 	WARN_ON(!inode_unhashed(inode));
+	WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
+	WARN_ON(OVL_I(inode)->__upperdentry);
+
 	/*
-	 * Make sure upperinode is consistent before making it visible to
-	 * ovl_inode_real();
+	 * Make sure upperdentry is consistent before making it visible
 	 */
 	smp_wmb();
-	OVL_I(inode)->upper = upperinode;
+	OVL_I(inode)->__upperdentry = upperdentry;
 	if (!S_ISDIR(upperinode->i_mode)) {
 		inode->i_private = upperinode;
 		__insert_inode_hash(inode, (unsigned long) upperinode);
@@ -311,7 +286,7 @@ int ovl_copy_up_start(struct dentry *dentry)
 	spin_lock(&ofs->copyup_wq.lock);
 	err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
 	if (!err) {
-		if (oe->__upperdentry)
+		if (ovl_dentry_upper(dentry))
 			err = 1; /* Already copied up */
 		else
 			oe->copying = true;