Re: [PATCH 6/8] Add support for recovery for a raid5 btrfs profiles.

[Goffredo Baroncelli]

On 05/14/2018 08:40 PM, Daniel Kiper wrote:
> On Fri, May 11, 2018 at 09:24:44PM +0200, Goffredo Baroncelli wrote:
>> Signed-off-by: Goffredo Baroncelli <address@hidden>
>> ---
>>  grub-core/fs/btrfs.c | 178 +++++++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 173 insertions(+), 5 deletions(-)
>>
>> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
>> index fc4198e39..8d72607d1 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+");
>>
>> @@ -663,9 +664,156 @@ 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  data_is_valid;
>> +};
>> +
>> +static void
>> +rebuild_raid5 (struct raid56_buffer *buffers, grub_uint64_t nstripes,
>> +               grub_uint64_t csize)
>> +{
>> +  grub_uint64_t target = 0, i;
>> +
>> +  while (buffers[target].data_is_valid && 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++)
> 
> Please drop extra space behind nstripes. I have found
> similar issues below too. Please fix all of them.
> 
>> +    if (i != target)
>> +      grub_crypto_xor (buffers[target].buf, buffers[target].buf, 
>> buffers[i].buf,
>> +                       csize);
>> +}
>> +
>> +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)
>> +{
>> +
>> +  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(*buffers) * nstripes);
>> +  if (!buffers)
>> +    {
>> +      ret = GRUB_ERR_OUT_OF_MEMORY;
>> +      goto cleanup;
>> +    }
>> +
>> +  for (i = 0; i < nstripes ; i++)
> 
> Ditto.
> 
>> +    {
>> +      buffers[i].buf = grub_zalloc (csize);
>> +      if (!buffers[i].buf)
>> +    {
>> +      ret = GRUB_ERR_OUT_OF_MEMORY;
>> +      goto cleanup;
>> +    }
>> +    }
>> +
>> +  for (i = 0; i < nstripes ; i++)
> 
> Ditto.
> 
>> +    {
>> +      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 */
> 
> Could you be more verbose here?
This was an initial comment. After few thoughts I concluded that it was wrong. 
So I 
removed it in the next patches set.

> 
>> +      dev = find_device (data, stripe->device_id);
>> +      if (!dev)
>> +    {
>> +      buffers[i].data_is_valid = 0;
>> +      grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " FAILED (dev ID 
>> %"
>> +                    PRIxGRUB_UINT64_T ")\n", i, stripe->device_id);
>> +      continue;
>> +    }
>> +
>> +      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].data_is_valid = 1;
>> +      grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " Ok (dev ID %"
>> +                    PRIxGRUB_UINT64_T ")\n", i, stripe->device_id);
>> +    }
>> +      else
>> +    {
>> +      buffers[i].data_is_valid = 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++)
>> +    if (!buffers[i].data_is_valid)
>> +      ++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
>> +    {
>> +      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
>> +    {
>> +      grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n");
>> +    }
>> +
>> +cleanup:
>> +
> 
> Drop empty line after cleanup label and add space before the label.
> 
>> +  if (buffers)
>> +    {
>> +      for (i = 0; i < nstripes ; i++)
>> +    if (buffers[i].buf)
>> +      grub_free(buffers[i].buf);
>> +      grub_free(buffers);
> 
> Please be more consistent in using spaces and tabs.
> 
>> +    }
>> +
>> +  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)
>> @@ -743,6 +891,11 @@ 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;
>> +    grub_uint64_t parities_pos = 0;
>> +
>> +        is_raid56 = !!(grub_le_to_cpu64 (chunk->type) &
>> +                GRUB_BTRFS_CHUNK_TYPE_RAID5);
> 
> Something is wrong with aligment.
> 
>>      if (grub_le_to_cpu64 (chunk->size) <= off)
>>        {
>> @@ -868,7 +1021,6 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, 
>> grub_disk_addr_t addr,
>>             *
>>             */
>>            stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low);
>> -
> 
> Drop this change please.
> 
> Daniel
> 


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