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,
-			   u64 inode_objectid, u64 ref_objectid, u64 *index);
+			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/inode.c

@@ -3641,7 +3641,7 @@ void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info)
 	spin_unlock(&fs_info->delayed_iput_lock);
 }
 
-/**
+/*
  * Wait for flushing all delayed iputs
  *
  * @fs_info:  the filesystem
@@ -4286,7 +4286,7 @@ int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
 static 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,
 				struct btrfs_rename_ctx *rename_ctx)
 {
 	struct btrfs_root *root = dir->root;
@@ -4304,8 +4304,7 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 
-	di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
-				    name, name_len, -1);
+	di = btrfs_lookup_dir_item(trans, root, path, dir_ino, name, -1);
 	if (IS_ERR_OR_NULL(di)) {
 		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto err;
@@ -4333,12 +4332,11 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 		}
 	}
 
-	ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
-				  dir_ino, &index);
+	ret = btrfs_del_inode_ref(trans, root, name, ino, dir_ino, &index);
 	if (ret) {
 		btrfs_info(fs_info,
 			"failed to delete reference to %.*s, inode %llu parent %llu",
-			name_len, name, ino, dir_ino);
+			name->len, name->name, ino, dir_ino);
 		btrfs_abort_transaction(trans, ret);
 		goto err;
 	}
@@ -4359,10 +4357,8 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 	 * operations on the log tree, increasing latency for applications.
 	 */
 	if (!rename_ctx) {
-		btrfs_del_inode_ref_in_log(trans, root, name, name_len, inode,
-					   dir_ino);
-		btrfs_del_dir_entries_in_log(trans, root, name, name_len, dir,
-					     index);
+		btrfs_del_inode_ref_in_log(trans, root, name, inode, dir_ino);
+		btrfs_del_dir_entries_in_log(trans, root, name, dir, index);
 	}
 
 	/*
@@ -4380,7 +4376,7 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 	if (ret)
 		goto out;
 
-	btrfs_i_size_write(dir, dir->vfs_inode.i_size - name_len * 2);
+	btrfs_i_size_write(dir, dir->vfs_inode.i_size - name->len * 2);
 	inode_inc_iversion(&inode->vfs_inode);
 	inode_inc_iversion(&dir->vfs_inode);
 	inode->vfs_inode.i_ctime = current_time(&inode->vfs_inode);
@@ -4393,10 +4389,11 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 
 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 ret;
-	ret = __btrfs_unlink_inode(trans, dir, inode, name, name_len, NULL);
+
+	ret = __btrfs_unlink_inode(trans, dir, inode, name, NULL);
 	if (!ret) {
 		drop_nlink(&inode->vfs_inode);
 		ret = btrfs_update_inode(trans, inode->root, inode);
@@ -4440,9 +4437,8 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
 	btrfs_record_unlink_dir(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
 			0);
 
-	ret = btrfs_unlink_inode(trans, BTRFS_I(dir),
-			BTRFS_I(d_inode(dentry)), dentry->d_name.name,
-			dentry->d_name.len);
+	ret = btrfs_unlink_inode(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
+				 &dentry->d_name);
 	if (ret)
 		goto out;
 
@@ -4467,8 +4463,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	struct extent_buffer *leaf;
 	struct btrfs_dir_item *di;
 	struct btrfs_key key;
-	const char *name = dentry->d_name.name;
-	int name_len = dentry->d_name.len;
+	const struct qstr *name = &dentry->d_name;
 	u64 index;
 	int ret;
 	u64 objectid;
@@ -4487,8 +4482,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
-				   name, name_len, -1);
+	di = btrfs_lookup_dir_item(trans, root, path, dir_ino, name, -1);
 	if (IS_ERR_OR_NULL(di)) {
 		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;
@@ -4514,8 +4508,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	 * call btrfs_del_root_ref, and it _shouldn't_ fail.
 	 */
 	if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID) {
-		di = btrfs_search_dir_index_item(root, path, dir_ino,
-						 name, name_len);
+		di = btrfs_search_dir_index_item(root, path, dir_ino, name);
 		if (IS_ERR_OR_NULL(di)) {
 			if (!di)
 				ret = -ENOENT;
@@ -4532,7 +4525,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	} else {
 		ret = btrfs_del_root_ref(trans, objectid,
 					 root->root_key.objectid, dir_ino,
-					 &index, name, name_len);
+					 &index, name);
 		if (ret) {
 			btrfs_abort_transaction(trans, ret);
 			goto out;
@@ -4545,7 +4538,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 
-	btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name_len * 2);
+	btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name->len * 2);
 	inode_inc_iversion(dir);
 	dir->i_mtime = current_time(dir);
 	dir->i_ctime = dir->i_mtime;
@@ -4567,6 +4560,7 @@ static noinline int may_destroy_subvol(struct btrfs_root *root)
 	struct btrfs_path *path;
 	struct btrfs_dir_item *di;
 	struct btrfs_key key;
+	struct qstr name = QSTR_INIT("default", 7);
 	u64 dir_id;
 	int ret;
 
@@ -4577,7 +4571,7 @@ static noinline int may_destroy_subvol(struct btrfs_root *root)
 	/* Make sure this root isn't set as the default subvol */
 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
 	di = btrfs_lookup_dir_item(NULL, fs_info->tree_root, path,
-				   dir_id, "default", 7, 0);
+				   dir_id, &name, 0);
 	if (di && !IS_ERR(di)) {
 		btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
 		if (key.objectid == root->root_key.objectid) {
@@ -4844,9 +4838,8 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 	last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
 
 	/* now the directory is empty */
-	err = btrfs_unlink_inode(trans, BTRFS_I(dir),
-			BTRFS_I(d_inode(dentry)), dentry->d_name.name,
-			dentry->d_name.len);
+	err = btrfs_unlink_inode(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
+				 &dentry->d_name);
 	if (!err) {
 		btrfs_i_size_write(BTRFS_I(inode), 0);
 		/*
@@ -5538,8 +5531,7 @@ void btrfs_evict_inode(struct inode *inode)
 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 			       struct btrfs_key *location, u8 *type)
 {
-	const char *name = dentry->d_name.name;
-	int namelen = dentry->d_name.len;
+	const struct qstr *name = &dentry->d_name;
 	struct btrfs_dir_item *di;
 	struct btrfs_path *path;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
@@ -5550,7 +5542,7 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 		return -ENOMEM;
 
 	di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
-			name, namelen, 0);
+				   name, 0);
 	if (IS_ERR_OR_NULL(di)) {
 		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;
@@ -5562,7 +5554,7 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 		ret = -EUCLEAN;
 		btrfs_warn(root->fs_info,
 "%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, location(%llu %u %llu))",
-			   __func__, name, btrfs_ino(BTRFS_I(dir)),
+			   __func__, name->name, btrfs_ino(BTRFS_I(dir)),
 			   location->objectid, location->type, location->offset);
 	}
 	if (!ret)
@@ -6321,8 +6313,7 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 {
 	struct inode *dir = args->dir;
 	struct inode *inode = args->inode;
-	const char *name = args->orphan ? NULL : args->dentry->d_name.name;
-	int name_len = args->orphan ? 0 : args->dentry->d_name.len;
+	const struct qstr *name = args->orphan ? NULL : &args->dentry->d_name;
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_root *root;
 	struct btrfs_inode_item *inode_item;
@@ -6423,7 +6414,7 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 			sizes[1] = 2 + sizeof(*ref);
 		} else {
 			key[1].offset = btrfs_ino(BTRFS_I(dir));
-			sizes[1] = name_len + sizeof(*ref);
+			sizes[1] = name->len + sizeof(*ref);
 		}
 	}
 
@@ -6462,10 +6453,12 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 			btrfs_set_inode_ref_index(path->nodes[0], ref, 0);
 			write_extent_buffer(path->nodes[0], "..", ptr, 2);
 		} else {
-			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,
 						  BTRFS_I(inode)->dir_index);
-			write_extent_buffer(path->nodes[0], name, ptr, name_len);
+			write_extent_buffer(path->nodes[0], name->name, ptr,
+					    name->len);
 		}
 	}
 
@@ -6526,7 +6519,7 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 		ret = btrfs_orphan_add(trans, BTRFS_I(inode));
 	} else {
 		ret = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode), name,
-				     name_len, 0, BTRFS_I(inode)->dir_index);
+				     0, BTRFS_I(inode)->dir_index);
 	}
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
@@ -6555,7 +6548,7 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
  */
 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 ret = 0;
 	struct btrfs_key key;
@@ -6574,17 +6567,17 @@ int btrfs_add_link(struct btrfs_trans_handle *trans,
 	if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
 		ret = btrfs_add_root_ref(trans, key.objectid,
 					 root->root_key.objectid, parent_ino,
-					 index, name, name_len);
+					 index, name);
 	} else if (add_backref) {
-		ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
-					     parent_ino, index);
+		ret = btrfs_insert_inode_ref(trans, root, name,
+					     ino, parent_ino, index);
 	}
 
 	/* Nothing to clean up yet */
 	if (ret)
 		return ret;
 
-	ret = btrfs_insert_dir_item(trans, name, name_len, parent_inode, &key,
+	ret = btrfs_insert_dir_item(trans, name, parent_inode, &key,
 				    btrfs_inode_type(&inode->vfs_inode), index);
 	if (ret == -EEXIST || ret == -EOVERFLOW)
 		goto fail_dir_item;
@@ -6594,7 +6587,7 @@ int btrfs_add_link(struct btrfs_trans_handle *trans,
 	}
 
 	btrfs_i_size_write(parent_inode, parent_inode->vfs_inode.i_size +
-			   name_len * 2);
+			   name->len * 2);
 	inode_inc_iversion(&parent_inode->vfs_inode);
 	/*
 	 * If we are replaying a log tree, we do not want to update the mtime
@@ -6619,15 +6612,15 @@ int btrfs_add_link(struct btrfs_trans_handle *trans,
 		int err;
 		err = btrfs_del_root_ref(trans, key.objectid,
 					 root->root_key.objectid, parent_ino,
-					 &local_index, name, name_len);
+					 &local_index, name);
 		if (err)
 			btrfs_abort_transaction(trans, err);
 	} else if (add_backref) {
 		u64 local_index;
 		int err;
 
-		err = btrfs_del_inode_ref(trans, root, name, name_len,
-					  ino, parent_ino, &local_index);
+		err = btrfs_del_inode_ref(trans, root, name, ino, parent_ino,
+					  &local_index);
 		if (err)
 			btrfs_abort_transaction(trans, err);
 	}
@@ -6747,7 +6740,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
 
 	err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
-			     dentry->d_name.name, dentry->d_name.len, 1, index);
+			     &dentry->d_name, 1, index);
 
 	if (err) {
 		drop_inode = 1;
@@ -9088,9 +9081,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 		/* force full log commit if subvolume involved. */
 		btrfs_set_log_full_commit(trans);
 	} else {
-		ret = btrfs_insert_inode_ref(trans, dest,
-					     new_dentry->d_name.name,
-					     new_dentry->d_name.len,
+		ret = btrfs_insert_inode_ref(trans, dest, &new_dentry->d_name,
 					     old_ino,
 					     btrfs_ino(BTRFS_I(new_dir)),
 					     old_idx);
@@ -9104,9 +9095,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 		/* force full log commit if subvolume involved. */
 		btrfs_set_log_full_commit(trans);
 	} else {
-		ret = btrfs_insert_inode_ref(trans, root,
-					     old_dentry->d_name.name,
-					     old_dentry->d_name.len,
+		ret = btrfs_insert_inode_ref(trans, root, &old_dentry->d_name,
 					     new_ino,
 					     btrfs_ino(BTRFS_I(old_dir)),
 					     new_idx);
@@ -9142,8 +9131,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	} else { /* src is an inode */
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(old_dir),
 					   BTRFS_I(old_dentry->d_inode),
-					   old_dentry->d_name.name,
-					   old_dentry->d_name.len,
+					   &old_dentry->d_name,
 					   &old_rename_ctx);
 		if (!ret)
 			ret = btrfs_update_inode(trans, root, BTRFS_I(old_inode));
@@ -9159,8 +9147,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	} else { /* dest is an inode */
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(new_dir),
 					   BTRFS_I(new_dentry->d_inode),
-					   new_dentry->d_name.name,
-					   new_dentry->d_name.len,
+					   &new_dentry->d_name,
 					   &new_rename_ctx);
 		if (!ret)
 			ret = btrfs_update_inode(trans, dest, BTRFS_I(new_inode));
@@ -9171,16 +9158,14 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
-			     new_dentry->d_name.name,
-			     new_dentry->d_name.len, 0, old_idx);
+			     &new_dentry->d_name, 0, old_idx);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out_fail;
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(old_dir), BTRFS_I(new_inode),
-			     old_dentry->d_name.name,
-			     old_dentry->d_name.len, 0, new_idx);
+			     &old_dentry->d_name, 0, new_idx);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out_fail;
@@ -9281,8 +9266,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 
 	/* check for collisions, even if the  name isn't there */
 	ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
-			     new_dentry->d_name.name,
-			     new_dentry->d_name.len);
+					     &new_dentry->d_name);
 
 	if (ret) {
 		if (ret == -EEXIST) {
@@ -9376,9 +9360,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 		/* force full log commit if subvolume involved. */
 		btrfs_set_log_full_commit(trans);
 	} else {
-		ret = btrfs_insert_inode_ref(trans, dest,
-					     new_dentry->d_name.name,
-					     new_dentry->d_name.len,
+		ret = btrfs_insert_inode_ref(trans, dest, &new_dentry->d_name,
 					     old_ino,
 					     btrfs_ino(BTRFS_I(new_dir)), index);
 		if (ret)
@@ -9402,10 +9384,8 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 		ret = btrfs_unlink_subvol(trans, old_dir, old_dentry);
 	} else {
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(old_dir),
-					BTRFS_I(d_inode(old_dentry)),
-					old_dentry->d_name.name,
-					old_dentry->d_name.len,
-					&rename_ctx);
+					   BTRFS_I(d_inode(old_dentry)),
+					   &old_dentry->d_name, &rename_ctx);
 		if (!ret)
 			ret = btrfs_update_inode(trans, root, BTRFS_I(old_inode));
 	}
@@ -9424,8 +9404,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 		} else {
 			ret = btrfs_unlink_inode(trans, BTRFS_I(new_dir),
 						 BTRFS_I(d_inode(new_dentry)),
-						 new_dentry->d_name.name,
-						 new_dentry->d_name.len);
+						 &new_dentry->d_name);
 		}
 		if (!ret && new_inode->i_nlink == 0)
 			ret = btrfs_orphan_add(trans,
@@ -9437,8 +9416,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
-			     new_dentry->d_name.name,
-			     new_dentry->d_name.len, 0, index);
+			     &new_dentry->d_name, 0, index);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out_fail;

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.c

@@ -597,6 +597,21 @@ static int overwrite_item(struct btrfs_trans_handle *trans,
 	return do_overwrite_item(trans, root, path, eb, slot, key);
 }
 
+static int read_alloc_one_name(struct extent_buffer *eb, void *start, int len,
+			       struct qstr *name)
+{
+	char *buf;
+
+	buf = kmalloc(len, GFP_NOFS);
+	if (!buf)
+		return -ENOMEM;
+
+	read_extent_buffer(eb, buf, (unsigned long)start, len);
+	name->name = buf;
+	name->len = len;
+	return 0;
+}
+
 /*
  * simple helper to read an inode off the disk from a given root
  * This can only be called for subvolume roots and not for the log
@@ -902,12 +917,11 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 static int unlink_inode_for_log_replay(struct btrfs_trans_handle *trans,
 				       struct btrfs_inode *dir,
 				       struct btrfs_inode *inode,
-				       const char *name,
-				       int name_len)
+				       const struct qstr *name)
 {
 	int ret;
 
-	ret = btrfs_unlink_inode(trans, dir, inode, name, name_len);
+	ret = btrfs_unlink_inode(trans, dir, inode, name);
 	if (ret)
 		return ret;
 	/*
@@ -934,8 +948,7 @@ static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
 {
 	struct btrfs_root *root = dir->root;
 	struct inode *inode;
-	char *name;
-	int name_len;
+	struct qstr name;
 	struct extent_buffer *leaf;
 	struct btrfs_key location;
 	int ret;
@@ -943,12 +956,10 @@ static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
 	leaf = path->nodes[0];
 
 	btrfs_dir_item_key_to_cpu(leaf, di, &location);
-	name_len = btrfs_dir_name_len(leaf, di);
-	name = kmalloc(name_len, GFP_NOFS);
-	if (!name)
+	ret = read_alloc_one_name(leaf, di + 1, btrfs_dir_name_len(leaf, di), &name);
+	if (ret)
 		return -ENOMEM;
 
-	read_extent_buffer(leaf, name, (unsigned long)(di + 1), name_len);
 	btrfs_release_path(path);
 
 	inode = read_one_inode(root, location.objectid);
@@ -961,10 +972,9 @@ static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
 	if (ret)
 		goto out;
 
-	ret = unlink_inode_for_log_replay(trans, dir, BTRFS_I(inode), name,
-			name_len);
+	ret = unlink_inode_for_log_replay(trans, dir, BTRFS_I(inode), &name);
 out:
-	kfree(name);
+	kfree(name.name);
 	iput(inode);
 	return ret;
 }
@@ -979,14 +989,14 @@ static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
 static noinline int inode_in_dir(struct btrfs_root *root,
 				 struct btrfs_path *path,
 				 u64 dirid, u64 objectid, u64 index,
-				 const char *name, int name_len)
+				 struct qstr *name)
 {
 	struct btrfs_dir_item *di;
 	struct btrfs_key location;
 	int ret = 0;
 
 	di = btrfs_lookup_dir_index_item(NULL, root, path, dirid,
-					 index, name, name_len, 0);
+					 index, name, 0);
 	if (IS_ERR(di)) {
 		ret = PTR_ERR(di);
 		goto out;
@@ -999,7 +1009,7 @@ static noinline int inode_in_dir(struct btrfs_root *root,
 	}
 
 	btrfs_release_path(path);
-	di = btrfs_lookup_dir_item(NULL, root, path, dirid, name, name_len, 0);
+	di = btrfs_lookup_dir_item(NULL, root, path, dirid, name, 0);
 	if (IS_ERR(di)) {
 		ret = PTR_ERR(di);
 		goto out;
@@ -1026,7 +1036,7 @@ static noinline int inode_in_dir(struct btrfs_root *root,
 static noinline int backref_in_log(struct btrfs_root *log,
 				   struct btrfs_key *key,
 				   u64 ref_objectid,
-				   const char *name, int namelen)
+				   const struct qstr *name)
 {
 	struct btrfs_path *path;
 	int ret;
@@ -1046,12 +1056,10 @@ static noinline int backref_in_log(struct btrfs_root *log,
 	if (key->type == BTRFS_INODE_EXTREF_KEY)
 		ret = !!btrfs_find_name_in_ext_backref(path->nodes[0],
 						       path->slots[0],
-						       ref_objectid,
-						       name, namelen);
+						       ref_objectid, name);
 	else
 		ret = !!btrfs_find_name_in_backref(path->nodes[0],
-						   path->slots[0],
-						   name, namelen);
+						   path->slots[0], name);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -1064,11 +1072,9 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
 				  struct btrfs_inode *dir,
 				  struct btrfs_inode *inode,
 				  u64 inode_objectid, u64 parent_objectid,
-				  u64 ref_index, char *name, int namelen)
+				  u64 ref_index, struct qstr *name)
 {
 	int ret;
-	char *victim_name;
-	int victim_name_len;
 	struct extent_buffer *leaf;
 	struct btrfs_dir_item *di;
 	struct btrfs_key search_key;
@@ -1100,43 +1106,40 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
 		ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
 		ptr_end = ptr + btrfs_item_size(leaf, path->slots[0]);
 		while (ptr < ptr_end) {
-			victim_ref = (struct btrfs_inode_ref *)ptr;
-			victim_name_len = btrfs_inode_ref_name_len(leaf,
-								   victim_ref);
-			victim_name = kmalloc(victim_name_len, GFP_NOFS);
-			if (!victim_name)
-				return -ENOMEM;
+			struct qstr victim_name;
 
-			read_extent_buffer(leaf, victim_name,
-					   (unsigned long)(victim_ref + 1),
-					   victim_name_len);
+			victim_ref = (struct btrfs_inode_ref *)ptr;
+			ret = read_alloc_one_name(leaf, (victim_ref + 1),
+				 btrfs_inode_ref_name_len(leaf, victim_ref),
+				 &victim_name);
+			if (ret)
+				return ret;
 
 			ret = backref_in_log(log_root, &search_key,
-					     parent_objectid, victim_name,
-					     victim_name_len);
+					     parent_objectid, &victim_name);
 			if (ret < 0) {
-				kfree(victim_name);
+				kfree(victim_name.name);
 				return ret;
 			} else if (!ret) {
 				inc_nlink(&inode->vfs_inode);
 				btrfs_release_path(path);
 
 				ret = unlink_inode_for_log_replay(trans, dir, inode,
-						victim_name, victim_name_len);
-				kfree(victim_name);
+						&victim_name);
+				kfree(victim_name.name);
 				if (ret)
 					return ret;
 				goto again;
 			}
-			kfree(victim_name);
+			kfree(victim_name.name);
 
-			ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
+			ptr = (unsigned long)(victim_ref + 1) + victim_name.len;
 		}
 	}
 	btrfs_release_path(path);
 
 	/* Same search but for extended refs */
-	extref = btrfs_lookup_inode_extref(NULL, root, path, name, namelen,
+	extref = btrfs_lookup_inode_extref(NULL, root, path, name,
 					   inode_objectid, parent_objectid, 0,
 					   0);
 	if (IS_ERR(extref)) {
@@ -1153,29 +1156,28 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
 		base = btrfs_item_ptr_offset(leaf, path->slots[0]);
 
 		while (cur_offset < item_size) {
-			extref = (struct btrfs_inode_extref *)(base + cur_offset);
+			struct qstr victim_name;
 
-			victim_name_len = btrfs_inode_extref_name_len(leaf, extref);
+			extref = (struct btrfs_inode_extref *)(base + cur_offset);
 
 			if (btrfs_inode_extref_parent(leaf, extref) != parent_objectid)
 				goto next;
 
-			victim_name = kmalloc(victim_name_len, GFP_NOFS);
-			if (!victim_name)
-				return -ENOMEM;
-			read_extent_buffer(leaf, victim_name, (unsigned long)&extref->name,
-					   victim_name_len);
+			ret = read_alloc_one_name(leaf, &extref->name,
+				 btrfs_inode_extref_name_len(leaf, extref),
+				 &victim_name);
+			if (ret)
+				return ret;
 
 			search_key.objectid = inode_objectid;
 			search_key.type = BTRFS_INODE_EXTREF_KEY;
 			search_key.offset = btrfs_extref_hash(parent_objectid,
-							      victim_name,
-							      victim_name_len);
+							      victim_name.name,
+							      victim_name.len);
 			ret = backref_in_log(log_root, &search_key,
-					     parent_objectid, victim_name,
-					     victim_name_len);
+					     parent_objectid, &victim_name);
 			if (ret < 0) {
-				kfree(victim_name);
+				kfree(victim_name.name);
 				return ret;
 			} else if (!ret) {
 				ret = -ENOENT;
@@ -1187,26 +1189,24 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
 
 					ret = unlink_inode_for_log_replay(trans,
 							BTRFS_I(victim_parent),
-							inode,
-							victim_name,
-							victim_name_len);
+							inode, &victim_name);
 				}
 				iput(victim_parent);
-				kfree(victim_name);
+				kfree(victim_name.name);
 				if (ret)
 					return ret;
 				goto again;
 			}
-			kfree(victim_name);
+			kfree(victim_name.name);
 next:
-			cur_offset += victim_name_len + sizeof(*extref);
+			cur_offset += victim_name.len + sizeof(*extref);
 		}
 	}
 	btrfs_release_path(path);
 
 	/* look for a conflicting sequence number */
 	di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
-					 ref_index, name, namelen, 0);
+					 ref_index, name, 0);
 	if (IS_ERR(di)) {
 		return PTR_ERR(di);
 	} else if (di) {
@@ -1217,8 +1217,7 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
 	btrfs_release_path(path);
 
 	/* look for a conflicting name */
-	di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir),
-				   name, namelen, 0);
+	di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir), name, 0);
 	if (IS_ERR(di)) {
 		return PTR_ERR(di);
 	} else if (di) {
@@ -1232,20 +1231,18 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
 }
 
 static int extref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr,
-			     u32 *namelen, char **name, u64 *index,
+			     struct qstr *name, u64 *index,
 			     u64 *parent_objectid)
 {
 	struct btrfs_inode_extref *extref;
+	int ret;
 
 	extref = (struct btrfs_inode_extref *)ref_ptr;
 
-	*namelen = btrfs_inode_extref_name_len(eb, extref);
-	*name = kmalloc(*namelen, GFP_NOFS);
-	if (*name == NULL)
-		return -ENOMEM;
-
-	read_extent_buffer(eb, *name, (unsigned long)&extref->name,
-			   *namelen);
+	ret = read_alloc_one_name(eb, &extref->name,
+				  btrfs_inode_extref_name_len(eb, extref), name);
+	if (ret)
+		return ret;
 
 	if (index)
 		*index = btrfs_inode_extref_index(eb, extref);
@@ -1256,18 +1253,17 @@ static int extref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr,
 }
 
 static int ref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr,
-			  u32 *namelen, char **name, u64 *index)
+			  struct qstr *name, u64 *index)
 {
 	struct btrfs_inode_ref *ref;
+	int ret;
 
 	ref = (struct btrfs_inode_ref *)ref_ptr;
 
-	*namelen = btrfs_inode_ref_name_len(eb, ref);
-	*name = kmalloc(*namelen, GFP_NOFS);
-	if (*name == NULL)
-		return -ENOMEM;
-
-	read_extent_buffer(eb, *name, (unsigned long)(ref + 1), *namelen);
+	ret = read_alloc_one_name(eb, ref + 1, btrfs_inode_ref_name_len(eb, ref),
+				  name);
+	if (ret)
+		return ret;
 
 	if (index)
 		*index = btrfs_inode_ref_index(eb, ref);
@@ -1309,28 +1305,24 @@ static int unlink_old_inode_refs(struct btrfs_trans_handle *trans,
 	ref_ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
 	ref_end = ref_ptr + btrfs_item_size(eb, path->slots[0]);
 	while (ref_ptr < ref_end) {
-		char *name = NULL;
-		int namelen;
+		struct qstr name;
 		u64 parent_id;
 
 		if (key->type == BTRFS_INODE_EXTREF_KEY) {
-			ret = extref_get_fields(eb, ref_ptr, &namelen, &name,
+			ret = extref_get_fields(eb, ref_ptr, &name,
 						NULL, &parent_id);
 		} else {
 			parent_id = key->offset;
-			ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
-					     NULL);
+			ret = ref_get_fields(eb, ref_ptr, &name, NULL);
 		}
 		if (ret)
 			goto out;
 
 		if (key->type == BTRFS_INODE_EXTREF_KEY)
 			ret = !!btrfs_find_name_in_ext_backref(log_eb, log_slot,
-							       parent_id, name,
-							       namelen);
+							       parent_id, &name);
 		else
-			ret = !!btrfs_find_name_in_backref(log_eb, log_slot,
-							   name, namelen);
+			ret = !!btrfs_find_name_in_backref(log_eb, log_slot, &name);
 
 		if (!ret) {
 			struct inode *dir;
@@ -1339,20 +1331,20 @@ static int unlink_old_inode_refs(struct btrfs_trans_handle *trans,
 			dir = read_one_inode(root, parent_id);
 			if (!dir) {
 				ret = -ENOENT;
-				kfree(name);
+				kfree(name.name);
 				goto out;
 			}
 			ret = unlink_inode_for_log_replay(trans, BTRFS_I(dir),
-						 inode, name, namelen);
-			kfree(name);
+						 inode, &name);
+			kfree(name.name);
 			iput(dir);
 			if (ret)
 				goto out;
 			goto again;
 		}
 
-		kfree(name);
-		ref_ptr += namelen;
+		kfree(name.name);
+		ref_ptr += name.len;
 		if (key->type == BTRFS_INODE_EXTREF_KEY)
 			ref_ptr += sizeof(struct btrfs_inode_extref);
 		else
@@ -1381,8 +1373,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 	struct inode *inode = NULL;
 	unsigned long ref_ptr;
 	unsigned long ref_end;
-	char *name = NULL;
-	int namelen;
+	struct qstr name;
 	int ret;
 	int log_ref_ver = 0;
 	u64 parent_objectid;
@@ -1426,7 +1417,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 
 	while (ref_ptr < ref_end) {
 		if (log_ref_ver) {
-			ret = extref_get_fields(eb, ref_ptr, &namelen, &name,
+			ret = extref_get_fields(eb, ref_ptr, &name,
 						&ref_index, &parent_objectid);
 			/*
 			 * parent object can change from one array
@@ -1439,15 +1430,13 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 				goto out;
 			}
 		} else {
-			ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
-					     &ref_index);
+			ret = ref_get_fields(eb, ref_ptr, &name, &ref_index);
 		}
 		if (ret)
 			goto out;
 
 		ret = inode_in_dir(root, path, btrfs_ino(BTRFS_I(dir)),
-				   btrfs_ino(BTRFS_I(inode)), ref_index,
-				   name, namelen);
+				   btrfs_ino(BTRFS_I(inode)), ref_index, &name);
 		if (ret < 0) {
 			goto out;
 		} else if (ret == 0) {
@@ -1461,7 +1450,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 			ret = __add_inode_ref(trans, root, path, log,
 					      BTRFS_I(dir), BTRFS_I(inode),
 					      inode_objectid, parent_objectid,
-					      ref_index, name, namelen);
+					      ref_index, &name);
 			if (ret) {
 				if (ret == 1)
 					ret = 0;
@@ -1470,7 +1459,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 
 			/* insert our name */
 			ret = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
-					     name, namelen, 0, ref_index);
+					     &name, 0, ref_index);
 			if (ret)
 				goto out;
 
@@ -1480,9 +1469,9 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 		}
 		/* Else, ret == 1, we already have a perfect match, we're done. */
 
-		ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + namelen;
-		kfree(name);
-		name = NULL;
+		ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + name.len;
+		kfree(name.name);
+		name.name = NULL;
 		if (log_ref_ver) {
 			iput(dir);
 			dir = NULL;
@@ -1506,7 +1495,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 	ret = overwrite_item(trans, root, path, eb, slot, key);
 out:
 	btrfs_release_path(path);
-	kfree(name);
+	kfree(name.name);
 	iput(dir);
 	iput(inode);
 	return ret;
@@ -1778,7 +1767,7 @@ static noinline int link_to_fixup_dir(struct btrfs_trans_handle *trans,
 static noinline int insert_one_name(struct btrfs_trans_handle *trans,
 				    struct btrfs_root *root,
 				    u64 dirid, u64 index,
-				    char *name, int name_len,
+				    const struct qstr *name,
 				    struct btrfs_key *location)
 {
 	struct inode *inode;
@@ -1796,7 +1785,7 @@ static noinline int insert_one_name(struct btrfs_trans_handle *trans,
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode), name,
-			name_len, 1, index);
+			     1, index);
 
 	/* FIXME, put inode into FIXUP list */
 
@@ -1856,8 +1845,7 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 				    struct btrfs_dir_item *di,
 				    struct btrfs_key *key)
 {
-	char *name;
-	int name_len;
+	struct qstr name;
 	struct btrfs_dir_item *dir_dst_di;
 	struct btrfs_dir_item *index_dst_di;
 	bool dir_dst_matches = false;
@@ -1875,17 +1863,11 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 	if (!dir)
 		return -EIO;
 
-	name_len = btrfs_dir_name_len(eb, di);
-	name = kmalloc(name_len, GFP_NOFS);
-	if (!name) {
-		ret = -ENOMEM;
+	ret = read_alloc_one_name(eb, di + 1, btrfs_dir_name_len(eb, di), &name);
+	if (ret)
 		goto out;
-	}
 
 	log_type = btrfs_dir_type(eb, di);
-	read_extent_buffer(eb, name, (unsigned long)(di + 1),
-		   name_len);
-
 	btrfs_dir_item_key_to_cpu(eb, di, &log_key);
 	ret = btrfs_lookup_inode(trans, root, path, &log_key, 0);
 	btrfs_release_path(path);
@@ -1895,7 +1877,7 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 	ret = 0;
 
 	dir_dst_di = btrfs_lookup_dir_item(trans, root, path, key->objectid,
-					   name, name_len, 1);
+					   &name, 1);
 	if (IS_ERR(dir_dst_di)) {
 		ret = PTR_ERR(dir_dst_di);
 		goto out;
@@ -1912,7 +1894,7 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 
 	index_dst_di = btrfs_lookup_dir_index_item(trans, root, path,
 						   key->objectid, key->offset,
-						   name, name_len, 1);
+						   &name, 1);
 	if (IS_ERR(index_dst_di)) {
 		ret = PTR_ERR(index_dst_di);
 		goto out;
@@ -1940,7 +1922,7 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 	search_key.objectid = log_key.objectid;
 	search_key.type = BTRFS_INODE_REF_KEY;
 	search_key.offset = key->objectid;
-	ret = backref_in_log(root->log_root, &search_key, 0, name, name_len);
+	ret = backref_in_log(root->log_root, &search_key, 0, &name);
 	if (ret < 0) {
 	        goto out;
 	} else if (ret) {
@@ -1953,8 +1935,7 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 	search_key.objectid = log_key.objectid;
 	search_key.type = BTRFS_INODE_EXTREF_KEY;
 	search_key.offset = key->objectid;
-	ret = backref_in_log(root->log_root, &search_key, key->objectid, name,
-			     name_len);
+	ret = backref_in_log(root->log_root, &search_key, key->objectid, &name);
 	if (ret < 0) {
 		goto out;
 	} else if (ret) {
@@ -1965,7 +1946,7 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 	}
 	btrfs_release_path(path);
 	ret = insert_one_name(trans, root, key->objectid, key->offset,
-			      name, name_len, &log_key);
+			      &name, &log_key);
 	if (ret && ret != -ENOENT && ret != -EEXIST)
 		goto out;
 	if (!ret)
@@ -1975,10 +1956,10 @@ static noinline int replay_one_name(struct btrfs_trans_handle *trans,
 
 out:
 	if (!ret && update_size) {
-		btrfs_i_size_write(BTRFS_I(dir), dir->i_size + name_len * 2);
+		btrfs_i_size_write(BTRFS_I(dir), dir->i_size + name.len * 2);
 		ret = btrfs_update_inode(trans, root, BTRFS_I(dir));
 	}
-	kfree(name);
+	kfree(name.name);
 	iput(dir);
 	if (!ret && name_added)
 		ret = 1;
@@ -2144,8 +2125,7 @@ static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
 	struct extent_buffer *eb;
 	int slot;
 	struct btrfs_dir_item *di;
-	int name_len;
-	char *name;
+	struct qstr name;
 	struct inode *inode = NULL;
 	struct btrfs_key location;
 
@@ -2160,22 +2140,16 @@ static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
 	eb = path->nodes[0];
 	slot = path->slots[0];
 	di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
-	name_len = btrfs_dir_name_len(eb, di);
-	name = kmalloc(name_len, GFP_NOFS);
-	if (!name) {
-		ret = -ENOMEM;
+	ret = read_alloc_one_name(eb, di + 1, btrfs_dir_name_len(eb, di), &name);
+	if (ret)
 		goto out;
-	}
-
-	read_extent_buffer(eb, name, (unsigned long)(di + 1), name_len);
 
 	if (log) {
 		struct btrfs_dir_item *log_di;
 
 		log_di = btrfs_lookup_dir_index_item(trans, log, log_path,
 						     dir_key->objectid,
-						     dir_key->offset,
-						     name, name_len, 0);
+						     dir_key->offset, &name, 0);
 		if (IS_ERR(log_di)) {
 			ret = PTR_ERR(log_di);
 			goto out;
@@ -2201,7 +2175,7 @@ static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
 
 	inc_nlink(inode);
 	ret = unlink_inode_for_log_replay(trans, BTRFS_I(dir), BTRFS_I(inode),
-					  name, name_len);
+					  &name);
 	/*
 	 * Unlike dir item keys, dir index keys can only have one name (entry) in
 	 * them, as there are no key collisions since each key has a unique offset
@@ -2210,7 +2184,7 @@ static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
 out:
 	btrfs_release_path(path);
 	btrfs_release_path(log_path);
-	kfree(name);
+	kfree(name.name);
 	iput(inode);
 	return ret;
 }
@@ -3449,7 +3423,7 @@ static int del_logged_dentry(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *log,
 			     struct btrfs_path *path,
 			     u64 dir_ino,
-			     const char *name, int name_len,
+			     const struct qstr *name,
 			     u64 index)
 {
 	struct btrfs_dir_item *di;
@@ -3459,7 +3433,7 @@ static int del_logged_dentry(struct btrfs_trans_handle *trans,
 	 * for dir item keys.
 	 */
 	di = btrfs_lookup_dir_index_item(trans, log, path, dir_ino,
-					 index, name, name_len, -1);
+					 index, name, -1);
 	if (IS_ERR(di))
 		return PTR_ERR(di);
 	else if (!di)
@@ -3496,7 +3470,7 @@ static int del_logged_dentry(struct btrfs_trans_handle *trans,
  */
 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)
 {
 	struct btrfs_path *path;
@@ -3523,7 +3497,7 @@ void btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
 	}
 
 	ret = del_logged_dentry(trans, root->log_root, path, btrfs_ino(dir),
-				name, name_len, index);
+				name, index);
 	btrfs_free_path(path);
 out_unlock:
 	mutex_unlock(&dir->log_mutex);
@@ -3535,7 +3509,7 @@ void btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
 /* see comments for btrfs_del_dir_entries_in_log */
 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)
 {
 	struct btrfs_root *log;
@@ -3556,7 +3530,7 @@ void btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans,
 	log = root->log_root;
 	mutex_lock(&inode->log_mutex);
 
-	ret = btrfs_del_inode_ref(trans, log, name, name_len, btrfs_ino(inode),
+	ret = btrfs_del_inode_ref(trans, log, name, btrfs_ino(inode),
 				  dirid, &index);
 	mutex_unlock(&inode->log_mutex);
 	if (ret < 0 && ret != -ENOENT)
@@ -5270,6 +5244,7 @@ static int btrfs_check_ref_name_override(struct extent_buffer *eb,
 		u32 this_len;
 		unsigned long name_ptr;
 		struct btrfs_dir_item *di;
+		struct qstr name_str;
 
 		if (key->type == BTRFS_INODE_REF_KEY) {
 			struct btrfs_inode_ref *iref;
@@ -5303,8 +5278,11 @@ static int btrfs_check_ref_name_override(struct extent_buffer *eb,
 		}
 
 		read_extent_buffer(eb, name, name_ptr, this_name_len);
+
+		name_str.name = name;
+		name_str.len = this_name_len;
 		di = btrfs_lookup_dir_item(NULL, inode->root, search_path,
-				parent, name, this_name_len, 0);
+				parent, &name_str, 0);
 		if (di && !IS_ERR(di)) {
 			struct btrfs_key di_key;
 
@@ -7505,8 +7483,7 @@ void btrfs_log_new_name(struct btrfs_trans_handle *trans,
 		 */
 		mutex_lock(&old_dir->log_mutex);
 		ret = del_logged_dentry(trans, log, path, btrfs_ino(old_dir),
-					old_dentry->d_name.name,
-					old_dentry->d_name.len, old_dir_index);
+					&old_dentry->d_name, old_dir_index);
 		if (ret > 0) {
 			/*
 			 * The dentry does not exist in the log, so record its

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);