btrfs: use struct qstr instead of name and namelen pairs

Many functions throughout btrfs take name buffer and name length
arguments. Most of these functions at the highest level are usually
called with these arguments extracted from a supplied dentry's name.
But the entire name can be passed instead, making each function a little
more elegant.

Each function whose arguments are currently the name and length
extracted from a dentry is herein converted to instead take a pointer to
the name in the dentry. The couple of calls to these calls without a
struct dentry are converted to create an appropriate qstr to pass in.
Additionally, every function which is only called with a name/len
extracted directly from a qstr is also converted.

This change has positive effect on stack consumption, frame of many
functions is reduced but this will be used in the future for fscrypt
related structures.
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -1516,11 +1516,11 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 
 /* root-item.c */
 int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
-		       u64 ref_id, u64 dirid, u64 sequence, const char *name,
-		       int name_len);
+		       u64 ref_id, u64 dirid, u64 sequence,
+		       const struct qstr *name);
 int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
-		       u64 ref_id, u64 dirid, u64 *sequence, const char *name,
-		       int name_len);
+		       u64 ref_id, u64 dirid, u64 *sequence,
+		       const struct qstr *name);
 int btrfs_del_root(struct btrfs_trans_handle *trans,
 		   const struct btrfs_key *key);
 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
@@ -1549,25 +1549,23 @@ int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info);
 
 /* dir-item.c */
 int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
-			  const char *name, int name_len);
-int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
-			  int name_len, struct btrfs_inode *dir,
+			  const struct qstr *name);
+int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
+			  const struct qstr *name, struct btrfs_inode *dir,
 			  struct btrfs_key *location, u8 type, u64 index);
 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 					     struct btrfs_root *root,
 					     struct btrfs_path *path, u64 dir,
-					     const char *name, int name_len,
-					     int mod);
+					     const struct qstr *name, int mod);
 struct btrfs_dir_item *
 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root,
 			    struct btrfs_path *path, u64 dir,
-			    u64 index, const char *name, int name_len,
-			    int mod);
+			    u64 index, const struct qstr *name, int mod);
 struct btrfs_dir_item *
 btrfs_search_dir_index_item(struct btrfs_root *root,
 			    struct btrfs_path *path, u64 dirid,
-			    const char *name, int name_len);
+			    const struct qstr *name);
 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 			      struct btrfs_root *root,
 			      struct btrfs_path *path,
@@ -1648,10 +1646,10 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry);
 int btrfs_set_inode_index(struct btrfs_inode *dir, u64 *index);
 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 		       struct btrfs_inode *dir, struct btrfs_inode *inode,
-		       const char *name, int name_len);
+		       const struct qstr *name);
 int btrfs_add_link(struct btrfs_trans_handle *trans,
 		   struct btrfs_inode *parent_inode, struct btrfs_inode *inode,
-		   const char *name, int name_len, int add_backref, u64 index);
+		   const struct qstr *name, int add_backref, u64 index);
 int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry);
 int btrfs_truncate_block(struct btrfs_inode *inode, loff_t from, loff_t len,
 			 int front);

fs/btrfs/dir-item.c

@@ -105,8 +105,8 @@ int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
  * to use for the second index (if one is created).
  * Will return 0 or -ENOMEM
  */
-int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
-			  int name_len, struct btrfs_inode *dir,
+int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
+			  const struct qstr *name, struct btrfs_inode *dir,
 			  struct btrfs_key *location, u8 type, u64 index)
 {
 	int ret = 0;
@@ -122,7 +122,7 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
 
 	key.objectid = btrfs_ino(dir);
 	key.type = BTRFS_DIR_ITEM_KEY;
-	key.offset = btrfs_name_hash(name, name_len);
+	key.offset = btrfs_name_hash(name->name, name->len);
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -130,9 +130,9 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
 
 	btrfs_cpu_key_to_disk(&disk_key, location);
 
-	data_size = sizeof(*dir_item) + name_len;
+	data_size = sizeof(*dir_item) + name->len;
 	dir_item = insert_with_overflow(trans, root, path, &key, data_size,
-					name, name_len);
+					name->name, name->len);
 	if (IS_ERR(dir_item)) {
 		ret = PTR_ERR(dir_item);
 		if (ret == -EEXIST)
@@ -144,11 +144,11 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
 	btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 	btrfs_set_dir_type(leaf, dir_item, type);
 	btrfs_set_dir_data_len(leaf, dir_item, 0);
-	btrfs_set_dir_name_len(leaf, dir_item, name_len);
+	btrfs_set_dir_name_len(leaf, dir_item, name->len);
 	btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 	name_ptr = (unsigned long)(dir_item + 1);
 
-	write_extent_buffer(leaf, name, name_ptr, name_len);
+	write_extent_buffer(leaf, name->name, name_ptr, name->len);
 	btrfs_mark_buffer_dirty(leaf);
 
 second_insert:
@@ -159,7 +159,7 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
 	}
 	btrfs_release_path(path);
 
-	ret2 = btrfs_insert_delayed_dir_index(trans, name, name_len, dir,
+	ret2 = btrfs_insert_delayed_dir_index(trans, name->name, name->len, dir,
 					      &disk_key, type, index);
 out_free:
 	btrfs_free_path(path);
@@ -208,7 +208,7 @@ static struct btrfs_dir_item *btrfs_lookup_match_dir(
 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 					     struct btrfs_root *root,
 					     struct btrfs_path *path, u64 dir,
-					     const char *name, int name_len,
+					     const struct qstr *name,
 					     int mod)
 {
 	struct btrfs_key key;
@@ -216,9 +216,10 @@ struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 
 	key.objectid = dir;
 	key.type = BTRFS_DIR_ITEM_KEY;
-	key.offset = btrfs_name_hash(name, name_len);
+	key.offset = btrfs_name_hash(name->name, name->len);
 
-	di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
+	di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
+				    name->len, mod);
 	if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
 		return NULL;
 
@@ -226,7 +227,7 @@ struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 }
 
 int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
-				   const char *name, int name_len)
+				   const struct qstr *name)
 {
 	int ret;
 	struct btrfs_key key;
@@ -242,9 +243,10 @@ int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
 
 	key.objectid = dir;
 	key.type = BTRFS_DIR_ITEM_KEY;
-	key.offset = btrfs_name_hash(name, name_len);
+	key.offset = btrfs_name_hash(name->name, name->len);
 
-	di = btrfs_lookup_match_dir(NULL, root, path, &key, name, name_len, 0);
+	di = btrfs_lookup_match_dir(NULL, root, path, &key, name->name,
+				    name->len, 0);
 	if (IS_ERR(di)) {
 		ret = PTR_ERR(di);
 		/* Nothing found, we're safe */
@@ -264,11 +266,8 @@ int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
 		goto out;
 	}
 
-	/*
-	 * see if there is room in the item to insert this
-	 * name
-	 */
-	data_size = sizeof(*di) + name_len;
+	/* See if there is room in the item to insert this name. */
+	data_size = sizeof(*di) + name->len;
 	leaf = path->nodes[0];
 	slot = path->slots[0];
 	if (data_size + btrfs_item_size(leaf, slot) +
@@ -305,8 +304,7 @@ struct btrfs_dir_item *
 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root,
 			    struct btrfs_path *path, u64 dir,
-			    u64 index, const char *name, int name_len,
-			    int mod)
+			    u64 index, const struct qstr *name, int mod)
 {
 	struct btrfs_dir_item *di;
 	struct btrfs_key key;
@@ -315,7 +313,8 @@ btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 	key.type = BTRFS_DIR_INDEX_KEY;
 	key.offset = index;
 
-	di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
+	di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
+				    name->len, mod);
 	if (di == ERR_PTR(-ENOENT))
 		return NULL;
 
@@ -323,9 +322,8 @@ btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 }
 
 struct btrfs_dir_item *
-btrfs_search_dir_index_item(struct btrfs_root *root,
-			    struct btrfs_path *path, u64 dirid,
-			    const char *name, int name_len)
+btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
+			    u64 dirid, const struct qstr *name)
 {
 	struct btrfs_dir_item *di;
 	struct btrfs_key key;
@@ -340,7 +338,7 @@ btrfs_search_dir_index_item(struct btrfs_root *root,
 			break;
 
 		di = btrfs_match_dir_item_name(root->fs_info, path,
-					       name, name_len);
+					       name->name, name->len);
 		if (di)
 			return di;
 	}

fs/btrfs/inode-item.c

@@ -14,8 +14,8 @@
 #include "accessors.h"
 
 struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
-						   int slot, const char *name,
-						   int name_len)
+						   int slot,
+						   const struct qstr *name)
 {
 	struct btrfs_inode_ref *ref;
 	unsigned long ptr;
@@ -31,9 +31,10 @@ struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
 		len = btrfs_inode_ref_name_len(leaf, ref);
 		name_ptr = (unsigned long)(ref + 1);
 		cur_offset += len + sizeof(*ref);
-		if (len != name_len)
+		if (len != name->len)
 			continue;
-		if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
+		if (memcmp_extent_buffer(leaf, name->name, name_ptr,
+					 name->len) == 0)
 			return ref;
 	}
 	return NULL;
@@ -41,7 +42,7 @@ struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
 
 struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
 		struct extent_buffer *leaf, int slot, u64 ref_objectid,
-		const char *name, int name_len)
+		const struct qstr *name)
 {
 	struct btrfs_inode_extref *extref;
 	unsigned long ptr;
@@ -64,9 +65,10 @@ struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
 		name_ptr = (unsigned long)(&extref->name);
 		ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
 
-		if (ref_name_len == name_len &&
+		if (ref_name_len == name->len &&
 		    btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
-		    (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0))
+		    (memcmp_extent_buffer(leaf, name->name, name_ptr,
+					  name->len) == 0))
 			return extref;
 
 		cur_offset += ref_name_len + sizeof(*extref);
@@ -79,7 +81,7 @@ struct btrfs_inode_extref *
 btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  struct btrfs_path *path,
-			  const char *name, int name_len,
+			  const struct qstr *name,
 			  u64 inode_objectid, u64 ref_objectid, int ins_len,
 			  int cow)
 {
@@ -88,7 +90,7 @@ btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
 
 	key.objectid = inode_objectid;
 	key.type = BTRFS_INODE_EXTREF_KEY;
-	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
 
 	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 	if (ret < 0)
@@ -96,13 +98,13 @@ btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
 	if (ret > 0)
 		return NULL;
 	return btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
-					      ref_objectid, name, name_len);
+					      ref_objectid, name);
 
 }
 
 static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 				  struct btrfs_root *root,
-				  const char *name, int name_len,
+				  const struct qstr *name,
 				  u64 inode_objectid, u64 ref_objectid,
 				  u64 *index)
 {
@@ -111,14 +113,14 @@ static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 	struct btrfs_inode_extref *extref;
 	struct extent_buffer *leaf;
 	int ret;
-	int del_len = name_len + sizeof(*extref);
+	int del_len = name->len + sizeof(*extref);
 	unsigned long ptr;
 	unsigned long item_start;
 	u32 item_size;
 
 	key.objectid = inode_objectid;
 	key.type = BTRFS_INODE_EXTREF_KEY;
-	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -136,7 +138,7 @@ static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 	 * readonly.
 	 */
 	extref = btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
-						ref_objectid, name, name_len);
+						ref_objectid, name);
 	if (!extref) {
 		btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL);
 		ret = -EROFS;
@@ -172,8 +174,7 @@ static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 }
 
 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
-			struct btrfs_root *root,
-			const char *name, int name_len,
+			struct btrfs_root *root, const struct qstr *name,
 			u64 inode_objectid, u64 ref_objectid, u64 *index)
 {
 	struct btrfs_path *path;
@@ -186,7 +187,7 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 	u32 sub_item_len;
 	int ret;
 	int search_ext_refs = 0;
-	int del_len = name_len + sizeof(*ref);
+	int del_len = name->len + sizeof(*ref);
 
 	key.objectid = inode_objectid;
 	key.offset = ref_objectid;
@@ -205,8 +206,7 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 
-	ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name,
-					 name_len);
+	ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name);
 	if (!ref) {
 		ret = -ENOENT;
 		search_ext_refs = 1;
@@ -223,7 +223,7 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 	ptr = (unsigned long)ref;
-	sub_item_len = name_len + sizeof(*ref);
+	sub_item_len = name->len + sizeof(*ref);
 	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 	memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 			      item_size - (ptr + sub_item_len - item_start));
@@ -237,7 +237,7 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 		 * name in our ref array. Find and remove the extended
 		 * inode ref then.
 		 */
-		return btrfs_del_inode_extref(trans, root, name, name_len,
+		return btrfs_del_inode_extref(trans, root, name,
 					      inode_objectid, ref_objectid, index);
 	}
 
@@ -251,12 +251,13 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
  */
 static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root,
-				     const char *name, int name_len,
-				     u64 inode_objectid, u64 ref_objectid, u64 index)
+				     const struct qstr *name,
+				     u64 inode_objectid, u64 ref_objectid,
+				     u64 index)
 {
 	struct btrfs_inode_extref *extref;
 	int ret;
-	int ins_len = name_len + sizeof(*extref);
+	int ins_len = name->len + sizeof(*extref);
 	unsigned long ptr;
 	struct btrfs_path *path;
 	struct btrfs_key key;
@@ -264,7 +265,7 @@ static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 
 	key.objectid = inode_objectid;
 	key.type = BTRFS_INODE_EXTREF_KEY;
-	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -276,7 +277,7 @@ static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 		if (btrfs_find_name_in_ext_backref(path->nodes[0],
 						   path->slots[0],
 						   ref_objectid,
-						   name, name_len))
+						   name))
 			goto out;
 
 		btrfs_extend_item(path, ins_len);
@@ -290,12 +291,12 @@ static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 	ptr += btrfs_item_size(leaf, path->slots[0]) - ins_len;
 	extref = (struct btrfs_inode_extref *)ptr;
 
-	btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
+	btrfs_set_inode_extref_name_len(path->nodes[0], extref, name->len);
 	btrfs_set_inode_extref_index(path->nodes[0], extref, index);
 	btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
 
 	ptr = (unsigned long)&extref->name;
-	write_extent_buffer(path->nodes[0], name, ptr, name_len);
+	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 
 out:
@@ -305,8 +306,7 @@ static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 
 /* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
-			   struct btrfs_root *root,
-			   const char *name, int name_len,
+			   struct btrfs_root *root, const struct qstr *name,
 			   u64 inode_objectid, u64 ref_objectid, u64 index)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -315,7 +315,7 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 	struct btrfs_inode_ref *ref;
 	unsigned long ptr;
 	int ret;
-	int ins_len = name_len + sizeof(*ref);
+	int ins_len = name->len + sizeof(*ref);
 
 	key.objectid = inode_objectid;
 	key.offset = ref_objectid;
@@ -331,7 +331,7 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 	if (ret == -EEXIST) {
 		u32 old_size;
 		ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
-						 name, name_len);
+						 name);
 		if (ref)
 			goto out;
 
@@ -340,7 +340,7 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 				     struct btrfs_inode_ref);
 		ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
-		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
+		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
 		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 		ptr = (unsigned long)(ref + 1);
 		ret = 0;
@@ -348,7 +348,7 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 		if (ret == -EOVERFLOW) {
 			if (btrfs_find_name_in_backref(path->nodes[0],
 						       path->slots[0],
-						       name, name_len))
+						       name))
 				ret = -EEXIST;
 			else
 				ret = -EMLINK;
@@ -357,11 +357,11 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 	} else {
 		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 				     struct btrfs_inode_ref);
-		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
+		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
 		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 		ptr = (unsigned long)(ref + 1);
 	}
-	write_extent_buffer(path->nodes[0], name, ptr, name_len);
+	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 
 out:
@@ -374,7 +374,6 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 		if (btrfs_super_incompat_flags(disk_super)
 		    & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
 			ret = btrfs_insert_inode_extref(trans, root, name,
-							name_len,
 							inode_objectid,
 							ref_objectid, index);
 	}

fs/btrfs/inode-item.h

@@ -64,33 +64,31 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root,
 			       struct btrfs_truncate_control *control);
 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
-			   struct btrfs_root *root,
-			   const char *name, int name_len,
+			   struct btrfs_root *root, const struct qstr *name,
 			   u64 inode_objectid, u64 ref_objectid, u64 index);
 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
-			   struct btrfs_root *root,
-			   const char *name, int name_len,
+			struct btrfs_root *root, const struct qstr *name,
 			u64 inode_objectid, u64 ref_objectid, u64 *index);
 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root,
 			     struct btrfs_path *path, u64 objectid);
-int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
-		       *root, struct btrfs_path *path,
+int btrfs_lookup_inode(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *root, struct btrfs_path *path,
 		       struct btrfs_key *location, int mod);
 
 struct btrfs_inode_extref *btrfs_lookup_inode_extref(
 			  struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  struct btrfs_path *path,
-			  const char *name, int name_len,
+			  const struct qstr *name,
 			  u64 inode_objectid, u64 ref_objectid, int ins_len,
 			  int cow);
 
 struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
-						   int slot, const char *name,
-						   int name_len);
+						   int slot,
+						   const struct qstr *name);
 struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
 		struct extent_buffer *leaf, int slot, u64 ref_objectid,
-		const char *name, int name_len);
+		const struct qstr *name);
 
 #endif

fs/btrfs/ioctl.c

@@ -951,6 +951,7 @@ static noinline int btrfs_mksubvol(const struct path *parent,
 	struct inode *dir = d_inode(parent->dentry);
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct dentry *dentry;
+	struct qstr name_str = QSTR_INIT(name, namelen);
 	int error;
 
 	error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
@@ -971,8 +972,7 @@ static noinline int btrfs_mksubvol(const struct path *parent,
 	 * check for them now when we can safely fail
 	 */
 	error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
-					       dir->i_ino, name,
-					       namelen);
+					       dir->i_ino, &name_str);
 	if (error)
 		goto out_dput;
 
@@ -3779,6 +3779,7 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
 	struct btrfs_trans_handle *trans;
 	struct btrfs_path *path = NULL;
 	struct btrfs_disk_key disk_key;
+	struct qstr name = QSTR_INIT("default", 7);
 	u64 objectid = 0;
 	u64 dir_id;
 	int ret;
@@ -3822,7 +3823,7 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
 
 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
 	di = btrfs_lookup_dir_item(trans, fs_info->tree_root, path,
-				   dir_id, "default", 7, 1);
+				   dir_id, &name, 1);
 	if (IS_ERR_OR_NULL(di)) {
 		btrfs_release_path(path);
 		btrfs_end_transaction(trans);

fs/btrfs/root-tree.c

@@ -330,9 +330,8 @@ int btrfs_del_root(struct btrfs_trans_handle *trans,
 }
 
 int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
-		       u64 ref_id, u64 dirid, u64 *sequence, const char *name,
-		       int name_len)
-
+		       u64 ref_id, u64 dirid, u64 *sequence,
+		       const struct qstr *name)
 {
 	struct btrfs_root *tree_root = trans->fs_info->tree_root;
 	struct btrfs_path *path;
@@ -359,8 +358,8 @@ int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
 				     struct btrfs_root_ref);
 		ptr = (unsigned long)(ref + 1);
 		if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||
-		    (btrfs_root_ref_name_len(leaf, ref) != name_len) ||
-		    memcmp_extent_buffer(leaf, name, ptr, name_len)) {
+		    (btrfs_root_ref_name_len(leaf, ref) != name->len) ||
+		    memcmp_extent_buffer(leaf, name->name, ptr, name->len)) {
 			ret = -ENOENT;
 			goto out;
 		}
@@ -403,8 +402,8 @@ int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
  * Will return 0, -ENOMEM, or anything from the CoW path
  */
 int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
-		       u64 ref_id, u64 dirid, u64 sequence, const char *name,
-		       int name_len)
+		       u64 ref_id, u64 dirid, u64 sequence,
+		       const struct qstr *name)
 {
 	struct btrfs_root *tree_root = trans->fs_info->tree_root;
 	struct btrfs_key key;
@@ -423,7 +422,7 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
 	key.offset = ref_id;
 again:
 	ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
-				      sizeof(*ref) + name_len);
+				      sizeof(*ref) + name->len);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		btrfs_free_path(path);
@@ -434,9 +433,9 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
 	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
 	btrfs_set_root_ref_dirid(leaf, ref, dirid);
 	btrfs_set_root_ref_sequence(leaf, ref, sequence);
-	btrfs_set_root_ref_name_len(leaf, ref, name_len);
+	btrfs_set_root_ref_name_len(leaf, ref, name->len);
 	ptr = (unsigned long)(ref + 1);
-	write_extent_buffer(leaf, name, ptr, name_len);
+	write_extent_buffer(leaf, name->name, ptr, name->len);
 	btrfs_mark_buffer_dirty(leaf);
 
 	if (key.type == BTRFS_ROOT_BACKREF_KEY) {

fs/btrfs/send.c

@@ -1597,13 +1597,17 @@ static int gen_unique_name(struct send_ctx *sctx,
 		return -ENOMEM;
 
 	while (1) {
+		struct qstr tmp_name;
+
 		len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu",
 				ino, gen, idx);
 		ASSERT(len < sizeof(tmp));
+		tmp_name.name = tmp;
+		tmp_name.len = strlen(tmp);
 
 		di = btrfs_lookup_dir_item(NULL, sctx->send_root,
 				path, BTRFS_FIRST_FREE_OBJECTID,
-				tmp, strlen(tmp), 0);
+				&tmp_name, 0);
 		btrfs_release_path(path);
 		if (IS_ERR(di)) {
 			ret = PTR_ERR(di);
@@ -1623,7 +1627,7 @@ static int gen_unique_name(struct send_ctx *sctx,
 
 		di = btrfs_lookup_dir_item(NULL, sctx->parent_root,
 				path, BTRFS_FIRST_FREE_OBJECTID,
-				tmp, strlen(tmp), 0);
+				&tmp_name, 0);
 		btrfs_release_path(path);
 		if (IS_ERR(di)) {
 			ret = PTR_ERR(di);
@@ -1753,13 +1757,13 @@ static int lookup_dir_item_inode(struct btrfs_root *root,
 	struct btrfs_dir_item *di;
 	struct btrfs_key key;
 	struct btrfs_path *path;
+	struct qstr name_str = QSTR_INIT(name, name_len);
 
 	path = alloc_path_for_send();
 	if (!path)
 		return -ENOMEM;
 
-	di = btrfs_lookup_dir_item(NULL, root, path,
-			dir, name, name_len, 0);
+	di = btrfs_lookup_dir_item(NULL, root, path, dir, &name_str, 0);
 	if (IS_ERR_OR_NULL(di)) {
 		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;

fs/btrfs/super.c

@@ -1423,6 +1423,7 @@ static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objec
 	struct btrfs_dir_item *di;
 	struct btrfs_path *path;
 	struct btrfs_key location;
+	struct qstr name = QSTR_INIT("default", 7);
 	u64 dir_id;
 
 	path = btrfs_alloc_path();
@@ -1435,7 +1436,7 @@ static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objec
 	 * to mount.
 	 */
 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
-	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
+	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
 	if (IS_ERR(di)) {
 		btrfs_free_path(path);
 		return PTR_ERR(di);

fs/btrfs/transaction.c

@@ -1678,8 +1678,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	/* check if there is a file/dir which has the same name. */
 	dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
 					 btrfs_ino(BTRFS_I(parent_inode)),
-					 dentry->d_name.name,
-					 dentry->d_name.len, 0);
+					 &dentry->d_name, 0);
 	if (dir_item != NULL && !IS_ERR(dir_item)) {
 		pending->error = -EEXIST;
 		goto dir_item_existed;
@@ -1774,7 +1773,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	ret = btrfs_add_root_ref(trans, objectid,
 				 parent_root->root_key.objectid,
 				 btrfs_ino(BTRFS_I(parent_inode)), index,
-				 dentry->d_name.name, dentry->d_name.len);
+				 &dentry->d_name);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto fail;
@@ -1806,9 +1805,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	if (ret < 0)
 		goto fail;
 
-	ret = btrfs_insert_dir_item(trans, dentry->d_name.name,
-				    dentry->d_name.len, BTRFS_I(parent_inode),
-				    &key, BTRFS_FT_DIR, index);
+	ret = btrfs_insert_dir_item(trans, &dentry->d_name,
+				    BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
+				    index);
 	/* We have check then name at the beginning, so it is impossible. */
 	BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
 	if (ret) {

fs/btrfs/tree-log.h

@@ -87,11 +87,11 @@ int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans,
 			  struct btrfs_log_ctx *ctx);
 void btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
 				  struct btrfs_root *root,
-				  const char *name, int name_len,
+				  const struct qstr *name,
 				  struct btrfs_inode *dir, u64 index);
 void btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root,
-				const char *name, int name_len,
+				const struct qstr *name,
 				struct btrfs_inode *inode, u64 dirid);
 void btrfs_end_log_trans(struct btrfs_root *root);
 void btrfs_pin_log_trans(struct btrfs_root *root);