[PATCH -next v2 1/6] ext4: init seq with random value in kmmpd

[Ye Bin]

If two host has the same nodename, and seq start from 0, May cause the
detection mechanism to fail.
So init seq with random value to accelerate conflict detection.

Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
---
 fs/ext4/mmp.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index cebea4270817..12af6dc8457b 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -122,6 +122,21 @@ void __dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
 		       (int)sizeof(mmp->mmp_bdevname), mmp->mmp_bdevname);
 }
 
+/*
+ * Get a random new sequence number but make sure it is not greater than
+ * EXT4_MMP_SEQ_MAX.
+ */
+static unsigned int mmp_new_seq(void)
+{
+	u32 new_seq;
+
+	do {
+		new_seq = prandom_u32();
+	} while (new_seq > EXT4_MMP_SEQ_MAX);
+
+	return new_seq;
+}
+
 /*
  * kmmpd will update the MMP sequence every s_mmp_update_interval seconds
  */
@@ -132,7 +147,7 @@ static int kmmpd(void *data)
 	struct buffer_head *bh = EXT4_SB(sb)->s_mmp_bh;
 	struct mmp_struct *mmp;
 	ext4_fsblk_t mmp_block;
-	u32 seq = 0;
+	u32 seq = mmp_new_seq();
 	unsigned long failed_writes = 0;
 	int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
 	unsigned mmp_check_interval;
@@ -258,21 +273,6 @@ void ext4_stop_mmpd(struct ext4_sb_info *sbi)
 	}
 }
 
-/*
- * Get a random new sequence number but make sure it is not greater than
- * EXT4_MMP_SEQ_MAX.
- */
-static unsigned int mmp_new_seq(void)
-{
-	u32 new_seq;
-
-	do {
-		new_seq = prandom_u32();
-	} while (new_seq > EXT4_MMP_SEQ_MAX);
-
-	return new_seq;
-}
-
 /*
  * Protect the filesystem from being mounted more than once.
  */
-- 
2.31.1