ext4: add ext3 report error to userspace by netlink

euleros inclusion
category: feature
feature: add ext3 report error to userspace by netlink
bugzilla: NA

--------------------------------

reason: This patch is used to implement abnormal alarm of ext3
file system.
You can achieve this by setting "FILESYSTEM_MONITOR" or
"FILESYSTEM_ALARM" on in configuration file.
With this setting, alarm will be raised whenext3 file system
 expection occurs.
Signed-off-by: Nlijinlin <lijinlin3@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

fs/ext4/ext4.h

@@ -55,7 +55,10 @@
 #endif
 
 #define NL_EXT4_ERROR_GROUP    1
+
+#define EXT3_ERROR_MAGIC       0xAE43125U
 #define EXT4_ERROR_MAGIC       0xAE32014U
+
 struct ext4_err_msg {
 	int magic;
 	char s_id[32];

fs/ext4/super.c

@@ -455,6 +455,8 @@ static void ext4_netlink_send_info(struct super_block *sb, int ext4_errno)
 	struct ext4_err_msg *msg;
 
 	if (ext4nl) {
+		if (IS_EXT2_SB(sb))
+			return;
 		size = NLMSG_SPACE(sizeof(struct ext4_err_msg));
 		skb = alloc_skb(size, GFP_ATOMIC);
 		if (!skb) {
@@ -466,7 +468,10 @@ static void ext4_netlink_send_info(struct super_block *sb, int ext4_errno)
 		if (!nlh)
 			goto nlmsg_failure;
 		msg = (struct ext4_err_msg *)NLMSG_DATA(nlh);
-		msg->magic = EXT4_ERROR_MAGIC;
+		if (IS_EXT3_SB(sb))
+			msg->magic = EXT3_ERROR_MAGIC;
+		else
+			msg->magic = EXT4_ERROR_MAGIC;
 		memcpy(msg->s_id, sb->s_id, sizeof(sb->s_id));
 		msg->s_flags = sb->s_flags;
 		msg->ext4_errno = ext4_errno;