On Thu, Sep 27, 2018 at 08:35:02PM +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 | 160 +++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 155 insertions(+), 5 deletions(-)
>
> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
> index 554f350c5..db8df0eea 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 +666,139 @@ 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;
> +
> + 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);
> +
> + 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);
> +
> + }
> +}
> +
> +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_OUT_OF_MEMORY;
> + grub_uint64_t i, failed_devices;
> +
> + buffers = grub_zalloc (sizeof(*buffers) * nstripes);
> + if (!buffers)
> + goto cleanup;
> +
> + for (i = 0; i < nstripes; i++)
> + {
> + buffers[i].buf = grub_zalloc (csize);
> + if (!buffers[i].buf)
> + 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 err;
> +
> + stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1) + i;
I think that "chunk + 1" requires short comment why...
> +
> + 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);
> +
> + 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);
> + failed_devices++;
> + continue;
> + }
> +
> + err = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS,
> + paddr & (GRUB_DISK_SECTOR_SIZE - 1),
> + csize, buffers[i].buf);
> + if (err == 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++;
> + }
> + }
> +
> + if (failed_devices > 1 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5))
> + {
> + grub_dprintf ("btrfs",
> + "not enough disks for RAID 5: 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 RAID 5 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 (buf, buffers, nstripes, csize);
> + else
> + grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n");
> +
> + ret = GRUB_ERR_NONE;
> + cleanup:
> + if (buffers)
> + for (i = 0; i < nstripes; i++)
> + 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)
> @@ -742,6 +876,10 @@ 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;
> +
> + is_raid56 = !!(grub_le_to_cpu64 (chunk->type) &
> + GRUB_BTRFS_CHUNK_TYPE_RAID5);
>
> if (grub_le_to_cpu64 (chunk->size) <= off)
> {
> @@ -922,17 +1060,29 @@ 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);
>
> - for (i = 0; i < redundancy; i++)
> + if (!is_raid56)
Why not "if (is_raid56)"? This looks more natural here.
> + for (i = 0; i < redundancy; i++)
> + {
> + err = btrfs_read_from_chunk (data, chunk, stripen,
> + stripe_offset,
> + i, /* redundancy */
> + csize, buf);
> + if (!err)
> + break;
> + grub_errno = GRUB_ERR_NONE;
> + }
> + else
> {
> err = btrfs_read_from_chunk (data, chunk, stripen,
> stripe_offset,
> - i, /* redundancy */
> + 0, /* no mirror */
> csize, buf);
> - if (!err)
> - break;
> grub_errno = GRUB_ERR_NONE;
> + if (err != GRUB_ERR_NONE)
Please be consistent and use "if (err)" here.
> + err = raid56_read_retry (data, chunk, stripe_offset,
> + csize, buf);
> }
> - if (i != redundancy)
> + if (err == GRUB_ERR_NONE)
if (!err) please...
Daniel
