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/[email protected]
Signed-off-by: Yunfeng Ye <[email protected]>
Cc: zhengbin <[email protected]>
Cc: Hu Shiyuan <[email protected]>
Cc: Feilong Lin <[email protected]>
Cc: Jan Kara <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: yeyunfeng-dev

fs/reiserfs/stree.c

@@ -2246,7 +2246,8 @@ int reiserfs_insert_item(struct reiserfs_transaction_handle *th,
 	/* also releases the path */
 	unfix_nodes(&s_ins_balance);
 #ifdef REISERQUOTA_DEBUG
-	reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
+	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));
 #endif