On 2019/11/28 下午6:50, Su Yue wrote:
>
>
> On 2019/11/28 3:54 PM, Qu Wenruo wrote:
>> There are several reports of hanging relocation, populating the dmesg
>> with things like:
>> BTRFS info (device dm-5): found 1 extents
>>
>> The investigation is still on going, but will never hurt to output a
>> little more info.
>>
>> This patch will also output the current relocation stage, making that
>> output something like:
>>
>> BTRFS info (device dm-5): balance: start -d -m -s
>> BTRFS info (device dm-5): relocating block group 30408704 flags
>> metadata|dup
>> BTRFS info (device dm-5): found 2 extents at MOVE_DATA_EXTENT stage
>> BTRFS info (device dm-5): relocating block group 22020096 flags
>> system|dup
>> BTRFS info (device dm-5): found 1 extents at MOVE_DATA_EXTENT stage
>> BTRFS info (device dm-5): relocating block group 13631488 flags data
>> BTRFS info (device dm-5): found 1 extents at MOVE_DATA_EXTENT stage
>> BTRFS info (device dm-5): found 1 extents at UPDATE_DATA_PTRS stage
>> BTRFS info (device dm-5): balance: ended with status: 0
>>
>> The string "MOVE_DATA_EXTENT" and "UPDATE_DATA_PTRS" is mostly from the
>> macro MOVE_DATA_EXTENTS and UPDATE_DATA_PTRS, but the 'S' from
>> MOVE_DATA_EXTENTS is removed in the output string to make the alignment
>> better.
>>
>> This patch will not increase the number of lines, but with extra info
>> for us to debug the reported problem.
>> (Although it's very likely the bug is sticking at UPDATE_DATA_PTRS
>> stage, even without the patch)
>>
>> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
>> ---
>> fs/btrfs/relocation.c | 16 ++++++++++++++--
>> 1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
>> index d897a8e5e430..88fd9182852d 100644
>> --- a/fs/btrfs/relocation.c
>> +++ b/fs/btrfs/relocation.c
>> @@ -4291,6 +4291,15 @@ static void describe_relocation(struct
>> btrfs_fs_info *fs_info,
>> block_group->start, buf);
>> }
>>
>> +static const char *stage_to_string(int stage)
>> +{
>> + if (stage == MOVE_DATA_EXTENTS)
>> + return "MOVE_DATA_EXTENT";
>> + if (stage == UPDATE_DATA_PTRS)
>> + return "UPDATE_DATA_PTRS";
>> + return "UNKNOWN";
>> +}
>> +
>> /*
>> * function to relocate all extents in a block group.
>> */
>> @@ -4365,12 +4374,15 @@ int btrfs_relocate_block_group(struct
>> btrfs_fs_info *fs_info, u64 group_start)
>> rc->block_group->length);
>>
>> while (1) {
>> + int finishes_stage;
>> +
>
> NIT: the rc::stage is an unsigned integer.
It doesn't matter. rc::stage is only a 8bit value.
Both unsigned int/int can handle it without any problem.
And the strage_to_string() function can handle any value, so no problem
at all.
Thanks,
Qu
>
>
>> mutex_lock(&fs_info->cleaner_mutex);
>> ret = relocate_block_group(rc);
>> mutex_unlock(&fs_info->cleaner_mutex);
>> if (ret < 0)
>> err = ret;
>>
>> + finishes_stage = rc->stage;
>> /*
>> * We may have gotten ENOSPC after we already dirtied some
>> * extents. If writeout happens while we're relocating a
>> @@ -4396,8 +4408,8 @@ int btrfs_relocate_block_group(struct
>> btrfs_fs_info *fs_info, u64 group_start)
>> if (rc->extents_found == 0)
>> break;
>>
>> - btrfs_info(fs_info, "found %llu extents", rc->extents_found);
>> -
>> + btrfs_info(fs_info, "found %llu extents at %s stage",
>> + rc->extents_found, stage_to_string(finishes_stage));
>> }
>>
>> WARN_ON(rc->block_group->pinned > 0);
>>
