On 25/09/2018 21.10, Daniel Kiper wrote:
> On Wed, Sep 19, 2018 at 08:40:38PM +0200, Goffredo Baroncelli wrote:
>> From: Goffredo Baroncelli <kreijack@xxxxxxxxx>
>>
>> Add support for recovery for a RAID 5 btrfs profile. In addition
>> it is added some code as preparatory work for RAID 6 recovery code.
>>
>> Signed-off-by: Goffredo Baroncelli <kreijack@xxxxxxxxx>
>> ---
>> grub-core/fs/btrfs.c | 169 +++++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 164 insertions(+), 5 deletions(-)
>>
>> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
>> index 5c1ebae77..55a7eeffc 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+");
>>
>> @@ -665,6 +666,148 @@ btrfs_read_from_chunk (struct grub_btrfs_data *data,
>> return err;
>> }
>>
>> +struct raid56_buffer {
>> + void *buf;
>> + int data_is_valid;
>> +};
>> +
>> +static void
>> +rebuild_raid5 (char *dest, struct raid56_buffer *buffers,
>> + grub_uint64_t nstripes, grub_uint64_t csize)
>> +{
>> + grub_uint64_t i;
>> + int first;
>> +
>> + i = 0;
>> + while (buffers[i].data_is_valid && i < nstripes)
>> + ++i;
>
> for (i = 0; buffers[i].data_is_valid && i < nstripes; i++);
>
>> + if (i == nstripes)
>> + {
>> + grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
>> + return;
>> + }
>> +
>> + grub_dprintf ("btrfs", "rebuilding RAID 5 stripe #%" PRIuGRUB_UINT64_T "\n",
>> + i);
>
> One line here please.
>
>> + for (i = 0, first = 1; i < nstripes; i++)
>> + {
>> + if (!buffers[i].data_is_valid)
>> + continue;
>> +
>> + if (first) {
>> + grub_memcpy(dest, buffers[i].buf, csize);
>> + first = 0;
>> + } else
>> + grub_crypto_xor (dest, dest, buffers[i].buf, csize);
>> +
>> + }
>
> Hmmm... I think that this function can be simpler. You can drop first
> while/for and "if (i == nstripes)". Then here:
>
> if (first) {
> grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n");
>
> Am I right?
Ehm.. no. The "if" is an internal check to avoid BUG. rebuild_raid5() should be called only if some disk is missed.
To perform this control, the code checks if all buffers are valid. Otherwise there is an internal BUG.
Checking "first" is a completely different test.
>> +}
>> +
>> +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 csize, void *buf)
>> +{
>> + struct raid56_buffer *buffers;
>> + 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;
>
> s/GRUB_ERR_NONE/GRUB_ERR_OUT_OF_MEMORY/ and then you can drop at
> least two relevant assigments and some curly brackets. Of course
> before cleanup label you have to add 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++)
>> + {
>> + buffers[i].buf = grub_zalloc (csize);
>> + if (!buffers[i].buf)
>> + {
>> + ret = GRUB_ERR_OUT_OF_MEMORY;
>> + goto cleanup;
>> + }
>> + }
>> +
>> + for (failed_devices = 0, i = 0; i < nstripes; i++)
>> + {
>> + struct grub_btrfs_chunk_stripe *stripe;
>> + grub_disk_addr_t paddr;
>> + grub_device_t dev;
>> + grub_err_t err2;
>
> s/err2/err/?
Ok
>
>> +
>> + stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1);
>> + stripe += i;
>
> Why not stripe = ((struct grub_btrfs_chunk_stripe *) (chunk + 1)) + i;?
Make sense
>
> Daniel
>
--
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
