Re: Fwd: [PATCH 4/9] btrfs: Avoid a rescan for a device which was already not found.

[Goffredo Baroncelli]

On 06/14/2018 01:45 PM, Daniel Kiper wrote:
> On Mon, Jun 04, 2018 at 09:26:06PM +0200, Goffredo Baroncelli wrote:
>> Resend this patch because I am not sure that all received it.
> 
> It looks that #4 is a bit unfortunate for you and/or patch series... :-)))

Yes, but I have another suspect: the patch #4 never changed, and I know that 
gmail "collapse" the emails when these are equal...
> 
>> BR
>> G.Baroncelli
>>
>>
>> -------- Forwarded Message --------
>> Subject: [PATCH 4/9] btrfs: Avoid a rescan for a device which was already 
>> not found.
>> Date: Sun,  3 Jun 2018 20:53:43 +0200
>> From: Goffredo Baroncelli <address@hidden>
>> To: address@hidden
>> CC: Goffredo Baroncelli <address@hidden>
>>
>> If a device is not found, record this failure by storing NULL in
>> data->devices_attached[]. This way we avoid unnecessary devices rescan,
> 
> Hmmm... Could you point me out where this store happens below?

Se below
[...]

>>    for (i = 0; i < data->n_devices_attached; i++)
>>      if (id == data->devices_attached[i].id)
>>        return data->devices_attached[i].dev;
>> -  if (do_rescan)
>> -    grub_device_iterate (find_device_iter, &ctx);
>> -  if (!ctx.dev_found)
>> -    {
>> -      return NULL;
>> -    }

The check above, performs a function exit if ctx.dev_found is NULL. Removing 
this check allows to store the NULL in the array.
In case of another iteration we know that the device is missing without doing a 
rescam

>> +
>> +  grub_device_iterate (find_device_iter, &ctx);
>> +
>>    data->n_devices_attached++;
>>    if (data->n_devices_attached > data->n_devices_allocated)
>>      {
>> @@ -617,7 +614,8 @@ find_device (struct grub_btrfs_data *data, grub_uint64_t 
>> id, int do_rescan)
>>                      * sizeof (data->devices_attached[0]));
>>        if (!data->devices_attached)
>>      {
>> -      grub_device_close (ctx.dev_found);
>> +      if (ctx.dev_found)
>> +        grub_device_close (ctx.dev_found);
>>        data->devices_attached = tmp;
>>        return NULL;
>>      }
>> @@ -896,7 +894,7 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, 
>> grub_disk_addr_t addr,
>>                            " for laddr 0x%" PRIxGRUB_UINT64_T "\n", paddr,
>>                            addr);
>>
>> -            dev = find_device (data, stripe->device_id, j);
>> +            dev = find_device (data, stripe->device_id);
>>              if (!dev)
>>                {
>>                  grub_dprintf ("btrfs",
>> @@ -973,7 +971,8 @@ grub_btrfs_unmount (struct grub_btrfs_data *data)
>>    unsigned i;
>>    /* The device 0 is closed one layer upper.  */
>>    for (i = 1; i < data->n_devices_attached; i++)
>> -    grub_device_close (data->devices_attached[i].dev);
>> +    if (data->devices_attached[i].dev)
>> +        grub_device_close (data->devices_attached[i].dev);
>>    grub_free (data->devices_attached);
>>    grub_free (data->extent);
>>    grub_free (data);
>> --
>> 2.17.1
>>
>>
>>
>> _______________________________________________
>> Grub-devel mailing list
>> address@hidden
>> https://lists.gnu.org/mailman/listinfo/grub-devel
>>
> 


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