Re: [RFC PATCH 1/5] hw/block: blk_check_size_and_read_all should report backend name

[David Edmondson]

On Monday, 2020-11-16 at 12:23:24 +01, Philippe Mathieu-Daudé wrote:

> On 11/16/20 11:42 AM, David Edmondson wrote:
>> If there are problems examining or reading data from the block
>> backend, the error messages should include an appropriate identifier
>> to assist in diagnoses.
>> 
>> Signed-off-by: David Edmondson <david.edmondson@oracle.com>
>> ---
>>  hw/block/block.c | 14 +++++++-------
>>  1 file changed, 7 insertions(+), 7 deletions(-)
>> 
>> diff --git a/hw/block/block.c b/hw/block/block.c
>> index 1e34573da7..8b284e1f14 100644
>> --- a/hw/block/block.c
>> +++ b/hw/block/block.c
>> @@ -20,9 +20,6 @@
>>   * BDRV_REQUEST_MAX_BYTES.
>>   * On success, return true.
>>   * On failure, store an error through @errp and return false.
>> - * Note that the error messages do not identify the block backend.
>> - * TODO Since callers don't either, this can result in confusing
>> - * errors.
>>   * This function not intended for actual block devices, which read on
>>   * demand.  It's for things like memory devices that (ab)use a block
>>   * backend to provide persistence.
>> @@ -32,17 +29,19 @@ bool blk_check_size_and_read_all(BlockBackend *blk, void 
>> *buf, hwaddr size,
>>  {
>>      int64_t blk_len;
>>      int ret;
>> +    const char *name = blk_name(blk);
>>  
>>      blk_len = blk_getlength(blk);
>>      if (blk_len < 0) {
>>          error_setg_errno(errp, -blk_len,
>> -                         "can't get size of block backend");
>> +                         "can't get size of block backend %s",
>
> Maybe '%s' to notice empty name?

Okay.

>> +                         name);
>>          return false;
>>      }
>>      if (blk_len != size) {
>>          error_setg(errp, "device requires %" HWADDR_PRIu " bytes, "
>> -                   "block backend provides %" PRIu64 " bytes",
>> -                   size, blk_len);
>> +                   "block backend %s provides %" PRIu64 " bytes",
>> +                   size, name, blk_len);
>>          return false;
>>      }
>>  
>> @@ -55,7 +54,8 @@ bool blk_check_size_and_read_all(BlockBackend *blk, void 
>> *buf, hwaddr size,
>>      assert(size <= BDRV_REQUEST_MAX_BYTES);
>>      ret = blk_pread(blk, 0, buf, size);
>>      if (ret < 0) {
>> -        error_setg_errno(errp, -ret, "can't read block backend");
>> +        error_setg_errno(errp, -ret, "can't read block backend %s",
>> +                         name);
>>          return false;
>>      }
>>      return true;
>> 

dme.
-- 
She looks like Eve Marie Saint in "On the Waterfront".