Re: [PATCH 4/5] btrfs: Allow barrier_all_devices to do per-chunk device check

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

在 2015年10月30日 16:32, Anand Jain 写道:
>
>
> Qu,
>
>   We shouldn't mark FS readonly when chunks are degradable.
>   As below.
>
> Thanks, Anand
>
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 39a2d57..dbb2483 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -3530,7 +3530,7 @@ static int write_all_supers(struct btrfs_root
> *root, int max_mirrors)
>
>          if (do_barriers) {
>                  ret = barrier_all_devices(root->fs_info);
> -               if (ret) {
> +               if (ret < 0) {
>                          mutex_unlock(
>
> &root->fs_info->fs_devices->device_list_mutex);
>                          btrfs_std_error(root->fs_info, ret,
>
>

Sorry, I didn't got the point here.

There should be no difference between ret and ret < 0,
as barrier_all_devices() will only return -EIO or 0.

Or I missed something?

Thanks,
Qu

>
>
> On 09/21/2015 10:10 AM, Qu Wenruo wrote:
>> The last user of num_tolerated_disk_barrier_failures is
>> barrier_all_devices().
>> But it's can be easily changed to new per-chunk degradable check
>> framework.
>>
>> Now btrfs_device will have two extra members, representing send/wait
>> error, set at write_dev_flush() time.
>> And then check it in a similar but more accurate behavior than old code.
>>
>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> ---
>>   fs/btrfs/disk-io.c | 13 +++++--------
>>   fs/btrfs/volumes.c |  6 +++++-
>>   fs/btrfs/volumes.h |  4 ++++
>>   3 files changed, 14 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>> index d64299f..7cd94e7 100644
>> --- a/fs/btrfs/disk-io.c
>> +++ b/fs/btrfs/disk-io.c
>> @@ -3400,8 +3400,6 @@ static int barrier_all_devices(struct
>> btrfs_fs_info *info)
>>   {
>>       struct list_head *head;
>>       struct btrfs_device *dev;
>> -    int errors_send = 0;
>> -    int errors_wait = 0;
>>       int ret;
>>
>>       /* send down all the barriers */
>> @@ -3410,7 +3408,7 @@ static int barrier_all_devices(struct
>> btrfs_fs_info *info)
>>           if (dev->missing)
>>               continue;
>>           if (!dev->bdev) {
>> -            errors_send++;
>> +            dev->err_send = 1;
>>               continue;
>>           }
>>           if (!dev->in_fs_metadata || !dev->writeable)
>> @@ -3418,7 +3416,7 @@ static int barrier_all_devices(struct
>> btrfs_fs_info *info)
>>
>>           ret = write_dev_flush(dev, 0);
>>           if (ret)
>> -            errors_send++;
>> +            dev->err_send = 1;
>>       }
>>
>>       /* wait for all the barriers */
>> @@ -3426,7 +3424,7 @@ static int barrier_all_devices(struct
>> btrfs_fs_info *info)
>>           if (dev->missing)
>>               continue;
>>           if (!dev->bdev) {
>> -            errors_wait++;
>> +            dev->err_wait = 1;
>>               continue;
>>           }
>>           if (!dev->in_fs_metadata || !dev->writeable)
>> @@ -3434,10 +3432,9 @@ static int barrier_all_devices(struct
>> btrfs_fs_info *info)
>>
>>           ret = write_dev_flush(dev, 1);
>>           if (ret)
>> -            errors_wait++;
>> +            dev->err_wait = 1;
>>       }
>> -    if (errors_send > info->num_tolerated_disk_barrier_failures ||
>> -        errors_wait > info->num_tolerated_disk_barrier_failures)
>> +    if (btrfs_check_degradable(info, info->sb->s_flags) < 0)
>>           return -EIO;
>>       return 0;
>>   }
>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>> index f1ef215..88266fa 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -6945,8 +6945,12 @@ int btrfs_check_degradable(struct btrfs_fs_info
>> *fs_info, unsigned flags)
>>               btrfs_get_num_tolerated_disk_barrier_failures(
>>                       map->type);
>>           for (i = 0; i < map->num_stripes; i++) {
>> -            if (map->stripes[i].dev->missing)
>> +            if (map->stripes[i].dev->missing ||
>> +                map->stripes[i].dev->err_wait ||
>> +                map->stripes[i].dev->err_send)
>>                   missing++;
>> +            map->stripes[i].dev->err_wait = 0;
>> +            map->stripes[i].dev->err_send = 0;
>>           }
>>           if (missing > max_tolerated) {
>>               ret = -EIO;
>> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
>> index fe758df..cd02556 100644
>> --- a/fs/btrfs/volumes.h
>> +++ b/fs/btrfs/volumes.h
>> @@ -76,6 +76,10 @@ struct btrfs_device {
>>       int can_discard;
>>       int is_tgtdev_for_dev_replace;
>>
>> +    /* for barrier_all_devices() check */
>> +    int err_send;
>> +    int err_wait;
>> +
>>   #ifdef __BTRFS_NEED_DEVICE_DATA_ORDERED
>>       seqcount_t data_seqcount;
>>   #endif
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html