reiserfs: prevent NULL pointer dereference in reiserfs_insert_item()

The variable inode may be NULL in reiserfs_insert_item(), but there is
no check before accessing the member of inode.

Fix this by adding NULL pointer check before calling reiserfs_debug().

Link: http://lkml.kernel.org/r/79c5135d-ff25-1cc9-4e99-9f572b88cc00@huawei.comSigned-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Cc: zhengbin <zhengbin13@huawei.com>
Cc: Hu Shiyuan <hushiyuan@huawei.com>
Cc: Feilong Lin <linfeilong@huawei.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/reiserfs/stree.c

@@ -2246,6 +2246,7 @@ int reiserfs_insert_item(struct reiserfs_transaction_handle *th,
 	/* also releases the path */
 	unfix_nodes(&s_ins_balance);
 #ifdef REISERQUOTA_DEBUG
+	if (inode)
 		reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
 		       "reiserquota insert_item(): freeing %u id=%u type=%c",
 		       quota_bytes, inode->i_uid, head2type(ih));