btrfs-progs: move btrfs_extref_hash() to hash.h

Move btrfs_extref_hash() from inode-item.c to hash.h,
so that the function can be called elsewhere.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>

hash.h

@@ -25,4 +25,14 @@ static inline u64 btrfs_name_hash(const char *name, int len)
 {
 	return crc32c((u32)~1, name, len);
 }
+
+/*
+ * Figure the key offset of an extended inode ref
+ */
+static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name,
+				    int len)
+{
+	return (u64)btrfs_crc32c(parent_objectid, name, len);
+}
+
 #endif

inode-item.c

@@ -19,7 +19,7 @@
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
-#include "crc32c.h"
+#include "hash.h"
 
 static int find_name_in_backref(struct btrfs_path *path, const char * name,
 			 int name_len, struct btrfs_inode_ref **ref_ret)
@@ -184,12 +184,6 @@ struct btrfs_inode_ref *btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
 		return ret_inode_ref;
 }
 
-static inline u64 btrfs_extref_hash(u64 parent_ino, const char *name,
-				    int namelen)
-{
-	return (u64)btrfs_crc32c(parent_ino, name, namelen);
-}
-
 static int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
 		u64 parent_ino, const char *name, int namelen,
 		struct btrfs_inode_extref **extref_ret)