Re: [PATCH] state: backend_bucket_direct: add debug prints on read/write

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 28.07.23 16:06, Johannes Zink wrote:
> Hi Ahmad,
> 
> thanks for your patch.
> 
> On 7/28/23 15:31, Ahmad Fatoum wrote:
>> We already have debug prints for the circular backend to help see how
>> much data is read/written for each bucket. Add similar debugging info
>> for the direct backend as well. Example with stride size of 2048 and
>> 44 bytes for the variable set:
>>
>>    barebox@board:/ state -l
>>    state: Read state from 0 length 68
>>    state: Read state from 2048 length 68
>>    state: Read state from 4096 length 68
>>
>>    barebox@board:/ state -s
>>    state: Written state to offset 0 length 68 data length 60
>>    state: Written state to offset 2048 length 68 data length 60
>>    state: Written state to offset 4096 length 68 data length 60
>>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> ---
>>   common/state/backend_bucket_direct.c | 14 +++++++++++++-
>>   1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/common/state/backend_bucket_direct.c b/common/state/backend_bucket_direct.c
>> index f06e14277862..03c752d6fe41 100644
>> --- a/common/state/backend_bucket_direct.c
>> +++ b/common/state/backend_bucket_direct.c
>> @@ -52,7 +52,7 @@ static int state_backend_bucket_direct_read(struct state_backend_storage_bucket
>>       struct state_backend_storage_bucket_direct *direct =
>>           get_bucket_direct(bucket);
>>       struct state_backend_storage_bucket_direct_meta meta;
>> -    uint32_t read_len;
>> +    uint32_t read_len, header_len = 0;
>>       void *buf;
>>       int ret;
>>   @@ -72,6 +72,8 @@ static int state_backend_bucket_direct_read(struct state_backend_storage_bucket
>>               return -EINVAL;
>>             }
>> +
>> +        header_len = sizeof(meta);
>>       } else {
>>           if (meta.magic != ~0 && !!meta.magic)
>>               bucket->wrong_magic = 1;
>> @@ -87,12 +89,16 @@ static int state_backend_bucket_direct_read(struct state_backend_storage_bucket
>>                   -errno);
>>               return -errno;
>>           }
>> +
>>       }
>>         buf = xmalloc(read_len);
>>       if (!buf)
>>           return -ENOMEM;
>>   +    dev_dbg(direct->dev, "Read state from %lld length %d\n", (long long) direct->offset,
>> +        header_len + read_len);
>> +
> 
> maybe this could use the same message format as for writing (i.e. total length and data length pointed out separately)?

I chose it this way for symmetry with the circular backend.

> 
> Best regards
> Johannes
> 
>>       ret = read_full(direct->fd, buf, read_len);
>>       if (ret < 0) {
>>           dev_err(direct->dev, "Failed to read from file, %d\n", ret);
>> @@ -112,6 +118,7 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket
>>   {
>>       struct state_backend_storage_bucket_direct *direct =
>>           get_bucket_direct(bucket);
>> +    size_t header_len = 0;
>>       int ret;
>>       struct state_backend_storage_bucket_direct_meta meta;
>>   @@ -129,6 +136,8 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket
>>               dev_err(direct->dev, "Failed to write metadata to file, %d\n", ret);
>>               return ret;
>>           }
>> +
>> +        header_len = sizeof(meta);
>>       } else {
>>           if (!IS_ENABLED(CONFIG_STATE_BACKWARD_COMPATIBLE)) {
>>               dev_dbg(direct->dev, "Too small stride size: must skip metadata! Increase stride size\n");
>> @@ -148,6 +157,9 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket
>>           return ret;
>>       }
>>   +    dev_dbg(direct->dev, "Written state to offset %lld length %zu data length %zu\n",
>> +        (long long)direct->offset, len + header_len, len);
>> +
>>       return 0;
>>   }
>>   
> 

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