btrfs: fix memory leak in __add_inode_ref()

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix memory leak in __add_inode_ref()

Line 1169 (#3) allocates a memory chunk for victim_name by kmalloc(),

but when the function returns in line 1184 (#4) victim_name allocated

by line 1169 (#3) is not freed, which will lead to a memory leak.

There is a similar snippet of code in this function as allocating a memory

chunk for victim_name in line 1104 (#1) as well as releasing the memory

in line 1116 (#2).

We should kfree() victim_name when the return value of backref_in_log()

is less than zero and before the function returns in line 1184 (#4).

1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans,

1058 struct btrfs_root *root,

1059 struct btrfs_path *path,

1060 struct btrfs_root *log_root,

1061 struct btrfs_inode *dir,

1062 struct btrfs_inode *inode,

1063 u64 inode_objectid, u64 parent_objectid,

1064 u64 ref_index, char *name, int namelen,

1065 int *search_done)

1066 {

1104 victim_name = kmalloc(victim_name_len, GFP_NOFS);

// #1: kmalloc (victim_name-1)

1105 if (!victim_name)

1106 return -ENOMEM;

1112 ret = backref_in_log(log_root, &search_key,

1113 parent_objectid, victim_name,

1114 victim_name_len);

1115 if (ret < 0) {

1116 kfree(victim_name); // #2: kfree (victim_name-1)

1117 return ret;

1118 } else if (!ret) {

1169 victim_name = kmalloc(victim_name_len, GFP_NOFS);

// #3: kmalloc (victim_name-2)

1170 if (!victim_name)

1171 return -ENOMEM;

1180 ret = backref_in_log(log_root, &search_key,

1181 parent_objectid, victim_name,

1182 victim_name_len);

1183 if (ret < 0) {

1184 return ret; // #4: missing kfree (victim_name-2)

1185 } else if (!ret) {

1241 return 0;

1242 }