ext4: use 'sbi' instead of 'EXT4_SB(sb)'

We could use 'sbi' instead of 'EXT4_SB(sb)' to make code more elegant.

Signed-off-by: Jun Piao <piaojun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index b32cf26..7830d28 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -303,7 +303,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 	/* Do this BEFORE marking the inode not in use or returning an error */
 	ext4_clear_inode(inode);
 
-	es = EXT4_SB(sb)->s_es;
+	es = sbi->s_es;
 	if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 		ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 		goto error_return;
@@ -1157,7 +1157,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 	ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
 	ext4_set_inode_state(inode, EXT4_STATE_NEW);
 
-	ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
+	ei->i_extra_isize = sbi->s_want_extra_isize;
 	ei->i_inline_off = 0;
 	if (ext4_has_feature_inline_data(sb))
 		ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);