Re: [PATCH] Btrfs: fix missing s_id setting

[Tsutomu Itoh <t-itoh@jp.fujitsu.com>]

On 2016/04/05 16:56, Anand Jain wrote:
> On 04/05/2016 08:08 AM, Tsutomu Itoh wrote:
>> When fs_devices->latest_bdev is deleted or is replaced, sb->s_id has
>> not been updated.
>> As a result, the deleted device name is displayed by btrfs_printk.
>>
>> [before fix]
>>   # btrfs dev del /dev/sdc4 /mnt2
>>   # btrfs dev add /dev/sdb6 /mnt2
>>
>>   [  217.458249] BTRFS info (device sdc4): found 1 extents
>>   [  217.695798] BTRFS info (device sdc4): disk deleted /dev/sdc4
>>   [  217.941284] BTRFS info (device sdc4): disk added /dev/sdb6
>>
>> [after fix]
>>   # btrfs dev del /dev/sdc4 /mnt2
>>   # btrfs dev add /dev/sdb6 /mnt2
>>
>>   [   83.835072] BTRFS info (device sdc4): found 1 extents
>>   [   84.080617] BTRFS info (device sdc3): disk deleted /dev/sdc4
>>   [   84.401951] BTRFS info (device sdc3): disk added /dev/sdb6
>
>
>   [PATCH 05/13] Btrfs: fix fs logging for multi device
>
>   any comments ?
>
>   We would want to maintain the logging prefix as constant, so that
>   troubleshooters with filters/scripts will find it helpful.

I think it is good to make the identifier constant for the troubleshooting.
However, fsid(uuid) is a little long for the print purpose, I think.
(But an appropriate value isn't found...)

Thanks,
Tsutomu

>
> Thanks, Anand
>
>
>> Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
>> ---
>>   fs/btrfs/dev-replace.c |  5 ++++-
>>   fs/btrfs/volumes.c     | 11 +++++++++--
>>   2 files changed, 13 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
>> index a1d6652..11c4198 100644
>> --- a/fs/btrfs/dev-replace.c
>> +++ b/fs/btrfs/dev-replace.c
>> @@ -560,8 +560,11 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
>>       tgt_device->commit_bytes_used = src_device->bytes_used;
>>       if (fs_info->sb->s_bdev == src_device->bdev)
>>           fs_info->sb->s_bdev = tgt_device->bdev;
>> -    if (fs_info->fs_devices->latest_bdev == src_device->bdev)
>> +    if (fs_info->fs_devices->latest_bdev == src_device->bdev) {
>>           fs_info->fs_devices->latest_bdev = tgt_device->bdev;
>> +        snprintf(fs_info->sb->s_id, sizeof(fs_info->sb->s_id), "%pg",
>> +             tgt_device->bdev);
>> +    }
>>       list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
>>       fs_info->fs_devices->rw_devices++;
>>
>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>> index e2b54d5..a471385 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -1846,8 +1846,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
>>                    struct btrfs_device, dev_list);
>>       if (device->bdev == root->fs_info->sb->s_bdev)
>>           root->fs_info->sb->s_bdev = next_device->bdev;
>> -    if (device->bdev == root->fs_info->fs_devices->latest_bdev)
>> +    if (device->bdev == root->fs_info->fs_devices->latest_bdev) {
>>           root->fs_info->fs_devices->latest_bdev = next_device->bdev;
>> +        snprintf(root->fs_info->sb->s_id,
>> +             sizeof(root->fs_info->sb->s_id), "%pg",
>> +             next_device->bdev);
>> +    }
>>
>>       if (device->bdev) {
>>           device->fs_devices->open_devices--;
>> @@ -2034,8 +2038,11 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
>>                    struct btrfs_device, dev_list);
>>       if (tgtdev->bdev == fs_info->sb->s_bdev)
>>           fs_info->sb->s_bdev = next_device->bdev;
>> -    if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
>> +    if (tgtdev->bdev == fs_info->fs_devices->latest_bdev) {
>>           fs_info->fs_devices->latest_bdev = next_device->bdev;
>> +        snprintf(fs_info->sb->s_id, sizeof(fs_info->sb->s_id), "%pg",
>> +             next_device->bdev);
>> +    }
>>       list_del_rcu(&tgtdev->dev_list);
>>
>>       call_rcu(&tgtdev->rcu, free_device);
>>
> --
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