diff mbox series

[-next,2/6] ext4: introduce last_check_time record previous check time

Message ID 20210906144754.2601607-3-yebin10@huawei.com
State Superseded
Headers show
Series Fix some issues about mmp | expand

Commit Message

yebin (H) Sept. 6, 2021, 2:47 p.m. UTC
kmmpd:
...
    diff = jiffies - last_update_time;
    if (diff > mmp_check_interval * HZ) {
...
As "mmp_check_interval = 2 * mmp_update_interval", 'diff' always little
than 'mmp_update_interval', so there will never trigger detection.
Introduce last_check_time record previous check time.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 fs/ext4/mmp.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

Comments

Guoqing Jiang Sept. 9, 2021, 2:20 a.m. UTC | #1
On 9/6/21 10:47 PM, Ye Bin wrote:
> kmmpd:
> ...
>      diff = jiffies - last_update_time;
>      if (diff > mmp_check_interval * HZ) {
> ...
> As "mmp_check_interval = 2 * mmp_update_interval", 'diff' always little
> than 'mmp_update_interval', so there will never trigger detection.
> Introduce last_check_time record previous check time.
>
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> ---
>   fs/ext4/mmp.c | 14 +++++++++-----
>   1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
> index 12af6dc8457b..89797f12a815 100644
> --- a/fs/ext4/mmp.c
> +++ b/fs/ext4/mmp.c
> @@ -152,6 +152,7 @@ static int kmmpd(void *data)
>   	int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
>   	unsigned mmp_check_interval;
>   	unsigned long last_update_time;
> +	unsigned long last_check_time;
>   	unsigned long diff;
>   	int retval = 0;
>   
> @@ -170,6 +171,7 @@ static int kmmpd(void *data)
>   
>   	memcpy(mmp->mmp_nodename, init_utsname()->nodename,
>   	       sizeof(mmp->mmp_nodename));
> +	last_update_time = jiffies;
>   
>   	while (!kthread_should_stop() && !sb_rdonly(sb)) {
>   		if (!ext4_has_feature_mmp(sb)) {
> @@ -198,17 +200,18 @@ static int kmmpd(void *data)
>   		}
>   
>   		diff = jiffies - last_update_time;
> -		if (diff < mmp_update_interval * HZ)
> +		if (diff < mmp_update_interval * HZ) {
>   			schedule_timeout_interruptible(mmp_update_interval *
>   						       HZ - diff);
> +			diff = jiffies - last_update_time;
> +		}
>   
>   		/*
>   		 * We need to make sure that more than mmp_check_interval
> -		 * seconds have not passed since writing. If that has happened
> -		 * we need to check if the MMP block is as we left it.
> +		 * seconds have not passed since check. If that has happened
> +		 * we need to check if the MMP block is as we write it.
>   		 */
> -		diff = jiffies - last_update_time;
> -		if (diff > mmp_check_interval * HZ) {
> +		if (jiffies - last_check_time > mmp_check_interval * HZ) {

Before the above checking, seems last_check_time is not initialized yet.
>   			struct buffer_head *bh_check = NULL;
>   			struct mmp_struct *mmp_check;
>   
> @@ -234,6 +237,7 @@ static int kmmpd(void *data)
>   				goto wait_to_exit;
>   			}
>   			put_bh(bh_check);
> +			last_check_time = jiffies;
>   		}
>   
>   		 /*

Thanks,
Guoqing
yebin (H) Sept. 10, 2021, 8:49 a.m. UTC | #2
On 2021/9/9 10:20, Guoqing Jiang wrote:
>
>
> On 9/6/21 10:47 PM, Ye Bin wrote:
>> kmmpd:
>> ...
>>      diff = jiffies - last_update_time;
>>      if (diff > mmp_check_interval * HZ) {
>> ...
>> As "mmp_check_interval = 2 * mmp_update_interval", 'diff' always little
>> than 'mmp_update_interval', so there will never trigger detection.
>> Introduce last_check_time record previous check time.
>>
>> Signed-off-by: Ye Bin <yebin10@huawei.com>
>> ---
>>   fs/ext4/mmp.c | 14 +++++++++-----
>>   1 file changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
>> index 12af6dc8457b..89797f12a815 100644
>> --- a/fs/ext4/mmp.c
>> +++ b/fs/ext4/mmp.c
>> @@ -152,6 +152,7 @@ static int kmmpd(void *data)
>>       int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
>>       unsigned mmp_check_interval;
>>       unsigned long last_update_time;
>> +    unsigned long last_check_time;
>>       unsigned long diff;
>>       int retval = 0;
>>   @@ -170,6 +171,7 @@ static int kmmpd(void *data)
>>         memcpy(mmp->mmp_nodename, init_utsname()->nodename,
>>              sizeof(mmp->mmp_nodename));
>> +    last_update_time = jiffies;
I'm sorry, actually i want to init 'last_check_time' at here,  I will 
fix it in v2.
Thanks,
YeBin
>>         while (!kthread_should_stop() && !sb_rdonly(sb)) {
>>           if (!ext4_has_feature_mmp(sb)) {
>> @@ -198,17 +200,18 @@ static int kmmpd(void *data)
>>           }
>>             diff = jiffies - last_update_time;
>> -        if (diff < mmp_update_interval * HZ)
>> +        if (diff < mmp_update_interval * HZ) {
>>               schedule_timeout_interruptible(mmp_update_interval *
>>                                  HZ - diff);
>> +            diff = jiffies - last_update_time;
>> +        }
>>             /*
>>            * We need to make sure that more than mmp_check_interval
>> -         * seconds have not passed since writing. If that has happened
>> -         * we need to check if the MMP block is as we left it.
>> +         * seconds have not passed since check. If that has happened
>> +         * we need to check if the MMP block is as we write it.
>>            */
>> -        diff = jiffies - last_update_time;
>> -        if (diff > mmp_check_interval * HZ) {
>> +        if (jiffies - last_check_time > mmp_check_interval * HZ) {
>
> Before the above checking, seems last_check_time is not initialized yet.
>>               struct buffer_head *bh_check = NULL;
>>               struct mmp_struct *mmp_check;
>>   @@ -234,6 +237,7 @@ static int kmmpd(void *data)
>>                   goto wait_to_exit;
>>               }
>>               put_bh(bh_check);
>> +            last_check_time = jiffies;
>>           }
>>              /*
>
> Thanks,
> Guoqing
> .
>
diff mbox series

Patch

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 12af6dc8457b..89797f12a815 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -152,6 +152,7 @@  static int kmmpd(void *data)
 	int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
 	unsigned mmp_check_interval;
 	unsigned long last_update_time;
+	unsigned long last_check_time;
 	unsigned long diff;
 	int retval = 0;
 
@@ -170,6 +171,7 @@  static int kmmpd(void *data)
 
 	memcpy(mmp->mmp_nodename, init_utsname()->nodename,
 	       sizeof(mmp->mmp_nodename));
+	last_update_time = jiffies;
 
 	while (!kthread_should_stop() && !sb_rdonly(sb)) {
 		if (!ext4_has_feature_mmp(sb)) {
@@ -198,17 +200,18 @@  static int kmmpd(void *data)
 		}
 
 		diff = jiffies - last_update_time;
-		if (diff < mmp_update_interval * HZ)
+		if (diff < mmp_update_interval * HZ) {
 			schedule_timeout_interruptible(mmp_update_interval *
 						       HZ - diff);
+			diff = jiffies - last_update_time;
+		}
 
 		/*
 		 * We need to make sure that more than mmp_check_interval
-		 * seconds have not passed since writing. If that has happened
-		 * we need to check if the MMP block is as we left it.
+		 * seconds have not passed since check. If that has happened
+		 * we need to check if the MMP block is as we write it.
 		 */
-		diff = jiffies - last_update_time;
-		if (diff > mmp_check_interval * HZ) {
+		if (jiffies - last_check_time > mmp_check_interval * HZ) {
 			struct buffer_head *bh_check = NULL;
 			struct mmp_struct *mmp_check;
 
@@ -234,6 +237,7 @@  static int kmmpd(void *data)
 				goto wait_to_exit;
 			}
 			put_bh(bh_check);
+			last_check_time = jiffies;
 		}
 
 		 /*