Re: [PATCH 6/7] Add support for recovery for a raid5 btrfs profiles.

[Goffredo Baroncelli]

On 05/09/2018 06:46 PM, Daniel Kiper wrote:
> On Tue, Apr 24, 2018 at 09:13:15PM +0200, Goffredo Baroncelli wrote:
>> Signed-off-by: Goffredo Baroncelli <address@hidden>
>> ---
>>  grub-core/fs/btrfs.c | 206 +++++++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 199 insertions(+), 7 deletions(-)
>>
>> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
>> index 697322125..5c76a68f3 100644
>> --- a/grub-core/fs/btrfs.c
>> +++ b/grub-core/fs/btrfs.c
>> @@ -29,6 +29,7 @@
>>  #include <minilzo.h>
>>  #include <grub/i18n.h>
>>  #include <grub/btrfs.h>
>> +#include <grub/crypto.h>
>>
>>  GRUB_MOD_LICENSE ("GPLv3+");
>>
>> @@ -661,9 +662,180 @@ btrfs_read_from_chunk (struct grub_btrfs_data *data,
>>      err = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS,
>>                        paddr & (GRUB_DISK_SECTOR_SIZE - 1),
>>                        csize, buf);
>> +    grub_dprintf ("btrfs", "reading paddr 0x%" PRIxGRUB_UINT64_T "\n", 
>> paddr);
>>      return err;
>>  }
>>
>> +struct raid56_buffer {
>> +  void *buf;
>> +  int  ok;
> 
> What ok is?
in the next series I renamed it as "data_is_valid"
> 
>> +};
>> +
>> +static void
>> +rebuild_raid5 (struct raid56_buffer *buffers, grub_uint64_t nstripes,
>> +               grub_uint64_t csize)
>> +{
>> +  grub_uint64_t target, i;
> 
> grub_uint64_t target = 0, i;
> 
>> +  target = 0;
> 
> ...then you can drop this.
ok
> 
>> +  while (buffers[target].ok && target < nstripes)
>> +    ++target;
>> +
>> +  if (target == nstripes)
>> +    {
>> +      grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are 
>> OK\n");
>> +      return;
>> +    }
>> +
>> +  grub_dprintf ("btrfs", "rebuilding raid5 stripe #%" PRIuGRUB_UINT64_T 
>> "\n",
>> +            target);
>> +  for (i = 0; i < nstripes ; i++)
>> +    if (i != target)
>> +      grub_crypto_xor (buffers[target].buf, buffers[target].buf, 
>> buffers[i].buf,
>> +                       csize);
>> +}
>> +
>> +static void
>> +rebuild_raid6 (struct raid56_buffer *buffers, grub_uint64_t nstripes,
>> +               grub_uint64_t csize, grub_uint64_t parities_pos, void *dest,
>> +               grub_uint64_t stripen)
>> +
>> +{
>> +  (void)buffers;
>> +  (void)nstripes;
>> +  (void)csize;
>> +  (void)parities_pos;
>> +  (void)dest;
>> +  (void)stripen;
>> +  grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n");
> 
> Could you add this function in next patch and print the relevant message
> below directly instead from rebuild_raid6()?
Ok
> 
>> +}
>> +
>> +static grub_err_t
>> +raid56_read_retry (struct grub_btrfs_data *data,
>> +               struct grub_btrfs_chunk_item *chunk,
>> +               grub_uint64_t stripe_offset, grub_uint64_t stripen,
>> +               grub_uint64_t csize, void *buf, grub_uint64_t parities_pos)
>> +{
>> +
>> +  struct raid56_buffer *buffers = NULL;
>> +  grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes);
>> +  grub_uint64_t chunk_type = grub_le_to_cpu64 (chunk->type);
>> +  grub_err_t ret = GRUB_ERR_NONE;
>> +  grub_uint64_t i, failed_devices;
>> +
>> +  buffers = grub_zalloc (sizeof(struct raid56_buffer)* nstripes);
> 
> ... sizeof (*buffers) * nstripes ...
ok
> 
>> +  if (!buffers)
>> +    {
>> +      ret = GRUB_ERR_OUT_OF_MEMORY;
>> +      goto cleanup;
>> +    }
>> +
>> +  for (i = 0 ; i < nstripes ; i++)
> 
> for (i = 0; i < nstripes; i++)
ok
> 
>> +    {
>> +      buffers[i].buf = grub_zalloc(csize);
> 
> ... grub_zalloc (csize);
ok
> 
>> +      if (!buffers[i].buf)
>> +    {
>> +      ret = GRUB_ERR_OUT_OF_MEMORY;
>> +      goto cleanup;
>> +    }
>> +    }
>> +
>> +  for (i = 0 ; i < nstripes ; i++)
> 
> Ditto.
ok
>> +    {
>> +      struct grub_btrfs_chunk_stripe *stripe;
>> +      grub_disk_addr_t paddr;
>> +      grub_device_t dev;
>> +      grub_err_t err2;
>> +
>> +      stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1);
>> +      stripe += i;
>> +
>> +      paddr = grub_le_to_cpu64 (stripe->offset) + stripe_offset;
>> +      grub_dprintf ("btrfs", "reading paddr %" PRIxGRUB_UINT64_T
>> +                    " from stripe ID %" PRIxGRUB_UINT64_T "\n", paddr,
>> +                    stripe->device_id);
>> +
>> +      /* FIXME: rescan the devices */
>> +      dev = find_device (data, stripe->device_id);
>> +      if (!dev)
>> +    {
>> +      buffers[i].ok = 0;
>> +      grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " FAILED (dev ID 
>> %"
>> +                    PRIxGRUB_UINT64_T ")\n", i, stripe->device_id);
>> +      continue;
>> +        }
> 
> Something is wrong with aligment.
ok
> 
>> +      err2 = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS,
>> +                         paddr & (GRUB_DISK_SECTOR_SIZE - 1),
>> +                         csize, buffers[i].buf);
>> +      if (err2 == GRUB_ERR_NONE)
>> +    {
>> +      buffers[i].ok = 1;
>> +      grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " Ok (dev ID %"
>> +                    PRIxGRUB_UINT64_T ")\n", i, stripe->device_id);
>> +    }
>> +      else
>> +    {
>> +      buffers[i].ok = 0;
>> +      grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T
>> +                    " FAILED (dev ID %" PRIxGRUB_UINT64_T ")\n", i,
>> +                    stripe->device_id);
>> +    }
>> +    }
>> +
>> +  failed_devices = 0;
>> +  for (i = 0 ; i < nstripes ; i++)
> 
> Ditto.
Ok
> 
>> +    if (!buffers[i].ok)
>> +      ++failed_devices;
>> +  if (failed_devices > 1 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5))
>> +    {
>> +      grub_dprintf ("btrfs",
>> +                "not enough disks for raid5: total %" PRIuGRUB_UINT64_T
>> +                ", missing %" PRIuGRUB_UINT64_T "\n",
>> +                nstripes, failed_devices);
>> +      ret = GRUB_ERR_READ_ERROR;
>> +      goto cleanup;
>> +    }
>> +  else if (failed_devices > 2 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID6))
>> +    {
>> +      grub_dprintf ("btrfs",
>> +                "not enough disks for raid6: total %" PRIuGRUB_UINT64_T
>> +                ", missing %" PRIuGRUB_UINT64_T "\n",
>> +                nstripes, failed_devices);
>> +      ret = GRUB_ERR_READ_ERROR;
>> +      goto cleanup;
>> +    }
> 
> This piece of code should be introduced in next patch.
ok
> 
>> +  else
>> +    {
>> +      grub_dprintf ("btrfs",
>> +                    "enough disks for raid5/6 rebuilding: total %"
>> +                PRIuGRUB_UINT64_T ", missing %" PRIuGRUB_UINT64_T "\n",
>> +                    nstripes, failed_devices);
>> +    }
>> +
>> +  /* if these are enough, try to rebuild the data */
>> +  if (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5)
>> +    {
>> +      rebuild_raid5 (buffers, nstripes, csize);
>> +      grub_memcpy (buf, buffers[stripen].buf, csize);
>> +    }
>> +  else
>> +    {
>> +      rebuild_raid6 (buffers, nstripes, csize, parities_pos, buf, stripen);
> 
> Please print not implemented messaged here instead of rebuild_raid6() call.
ok
> 
>> +    }
>> +
>> +cleanup:
> 
> Please add one space before the label.
ok
> 
>> +  if (buffers)
>> +    {
>> +      for (i = 0 ; i < nstripes ; i++)
> 
> Ditto.
ok
> 
>> +    if (buffers[i].buf)
>> +      grub_free(buffers[i].buf);
>> +      grub_free(buffers);
>> +    }
>> +
>> +  return ret;
>> +}
>> +
>>  static grub_err_t
>>  grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t 
>> addr,
>>                       void *buf, grub_size_t size, int recursion_depth)
>> @@ -741,6 +913,11 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, 
>> grub_disk_addr_t addr,
>>      grub_uint16_t nstripes;
>>      unsigned redundancy = 1;
>>      unsigned i, j;
>> +        int is_raid56;
ok
> 
> Incorrect aligment.
> 
>> +    grub_uint64_t parities_pos = 0;
>> +
>> +        is_raid56 = !!(grub_le_to_cpu64 (chunk->type) &
>> +                (GRUB_BTRFS_CHUNK_TYPE_RAID5|GRUB_BTRFS_CHUNK_TYPE_RAID6));
> 
> Do we need GRUB_BTRFS_CHUNK_TYPE_RAID6 here? Or maybe this
> should be introduced by next patch?
ok
> 
>>      if (grub_le_to_cpu64 (chunk->size) <= off)
>>        {
>> @@ -844,9 +1021,10 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, 
>> grub_disk_addr_t addr,
>>              }
>>
>>            stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low);
>> -
>>            high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen);
>>            grub_divmod64 (high + stripen, nstripes, &stripen);
>> +          grub_divmod64 (high + nstripes - nparities, nstripes,
>> +                         &parities_pos);
>>
>>            stripe_offset = low + chunk_stripe_length * high;
>>            csize = chunk_stripe_length - low;
>> @@ -881,12 +1059,26 @@ grub_btrfs_read_logical (struct grub_btrfs_data 
>> *data, grub_disk_addr_t addr,
>>          grub_dprintf ("btrfs", "reading laddr 0x%" PRIxGRUB_UINT64_T "\n",
>>                        addr);
>>
>> -        err = GRUB_ERR_NONE + 1;
>> -        for (i = 0; i < redundancy && err != GRUB_ERR_NONE; i++)
>> -             err = btrfs_read_from_chunk (data, chunk, stripen,
>> -                                          stripe_offset,
>> -                                          i,     /* redundancy */
>> -                                          csize, buf);
>> +        if (!is_raid56)
>> +          {
>> +            err = GRUB_ERR_NONE+1;
> 
> What?
Ok, I correct it
> 
> Daniel
> 


-- 
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D  17B2 0EDA 9B37 8B82 E0B5