btrfs: Code cleanup

Attaching below is some of the code cleanups that i came across while
reading the code.

a) alloc_path already calls init_path.
b) Mention that btrfs_inode is the in memory copy.Ext4 have ext4_inode_info as
the in memory copy ext4_inode as the disk copy
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/btrfs_inode.h

@@ -19,6 +19,7 @@
 #ifndef __BTRFS_I__
 #define __BTRFS_I__
 
+/* in memory btrfs inode */
 struct btrfs_inode {
 	struct btrfs_root *root;
 	struct btrfs_block_group_cache *block_group;

fs/btrfs/ctree.c

@@ -1647,7 +1647,6 @@ int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
 	if (!ret) {
 		ptr = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),

fs/btrfs/dir-item.c

@@ -74,7 +74,6 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 	ret = btrfs_name_hash(name, name_len, &key.offset);
 	BUG_ON(ret);
 	path = btrfs_alloc_path();
-	btrfs_init_path(path);
 	data_size = sizeof(*dir_item) + name_len;
 	dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 					name, name_len);

fs/btrfs/extent-tree.c

@@ -402,7 +402,6 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 &ins, 0);
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	key.objectid = blocknr;
 	key.flags = 0;
 	btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
@@ -437,7 +436,6 @@ static int lookup_extent_ref(struct btrfs_trans_handle *trans,
 	struct btrfs_extent_item *item;
 
 	path = btrfs_alloc_path();
-	btrfs_init_path(path);
 	key.objectid = blocknr;
 	key.offset = num_blocks;
 	key.flags = 0;
@@ -807,7 +805,6 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 	find_free_extent(trans, root, 0, 0, (u64)-1, 0, &ins, 0);
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 
 	ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
 	if (ret) {
@@ -1463,7 +1460,6 @@ int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 
 	level = btrfs_header_level(btrfs_buffer_header(snap));
 	orig_level = level;

fs/btrfs/file-item.c

@@ -38,7 +38,6 @@ int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	file_key.objectid = objectid;
 	file_key.offset = pos;
 	file_key.flags = 0;
@@ -274,7 +273,6 @@ int btrfs_csum_verify_file_block(struct btrfs_root *root,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	file_key.objectid = objectid;
 	file_key.offset = offset;
 	file_key.flags = 0;

fs/btrfs/inode-item.c

@@ -35,7 +35,6 @@ int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	ret = btrfs_insert_item(trans, root, &key, inode_item,
 				sizeof(*inode_item));
 	btrfs_release_path(root, path);

fs/btrfs/inode.c

@@ -79,7 +79,6 @@ void btrfs_read_locked_inode(struct inode *inode)
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	mutex_lock(&root->fs_info->fs_mutex);
 
 	memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
@@ -177,7 +176,6 @@ static int btrfs_update_inode(struct btrfs_trans_handle *trans,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	ret = btrfs_lookup_inode(trans, root, path,
 				 &BTRFS_I(inode)->location, 1);
 	if (ret) {
@@ -214,7 +212,6 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
 				    name, name_len, -1);
 	if (IS_ERR(di)) {
@@ -289,7 +286,6 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	mutex_lock(&root->fs_info->fs_mutex);
 	trans = btrfs_start_transaction(root, 1);
 	btrfs_set_trans_block_group(trans, dir);
@@ -360,7 +356,6 @@ static int btrfs_free_inode(struct btrfs_trans_handle *trans,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	ret = btrfs_lookup_inode(trans, root, path,
 				 &BTRFS_I(inode)->location, -1);
 	BUG_ON(ret);
@@ -687,7 +682,6 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
 				    namelen, 0);
 	if (!di || IS_ERR(di)) {
@@ -874,7 +868,6 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 	btrfs_set_key_type(&key, key_type);
 	key.offset = filp->f_pos;
 	path = btrfs_alloc_path();
-	btrfs_init_path(path);
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
 		goto err;
@@ -1263,7 +1256,6 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	if (create & BTRFS_GET_BLOCK_CREATE) {
 		WARN_ON(1);
 		/* this almost but not quite works */
@@ -1280,7 +1272,7 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
 	}
 
 	ret = btrfs_lookup_file_extent(NULL, root, path,
-				       inode->i_ino,
+				       objectid,
 				       iblock << inode->i_blkbits, 0);
 	if (ret < 0) {
 		err = ret;

fs/btrfs/root-tree.c

@@ -36,7 +36,6 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
 	if (ret < 0)
 		goto out;
@@ -70,7 +69,6 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	ret = btrfs_search_slot(trans, root, key, path, 0, 1);
 	if (ret < 0)
 		goto out;
@@ -106,7 +104,6 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
-	btrfs_init_path(path);
 	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
 	if (ret < 0)
 		goto out;