Hi All,
Below you can find a patch to add support for accessing files from grub in a
RAID5/6 btrfs filesystem. This is a RFC because it is missing the support for
recovery (i.e. if some devices are missed). In the next days (weeks ?) I will
extend this patch to support also this case.
Comments are welcome.
BR
G.Baroncelli
---
commit 8c80a1b7c913faf50f95c5c76b4666ed17685666
Author: Goffredo Baroncelli <kreij...@inwind.it>
Date: Tue Apr 17 21:40:31 2018 +0200
Add initial support for btrfs raid5/6 chunk
diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
index be195448d..4c5632acb 100644
--- a/grub-core/fs/btrfs.c
+++ b/grub-core/fs/btrfs.c
@@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item
#define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10
#define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20
#define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40
+#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80
+#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100
grub_uint8_t dummy2[0xc];
grub_uint16_t nstripes;
grub_uint16_t nsubstripes;
@@ -764,6 +766,39 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data,
grub_disk_addr_t addr,
stripe_offset = low + chunk_stripe_length
* high;
csize = chunk_stripe_length - low;
+ break;
+ }
+ case GRUB_BTRFS_CHUNK_TYPE_RAID5:
+ case GRUB_BTRFS_CHUNK_TYPE_RAID6:
+ {
+ grub_uint64_t nparities;
+ grub_uint64_t parity_pos;
+ grub_uint64_t stripe_nr, high;
+ grub_uint64_t low;
+
+ redundancy = 1; /* no redundancy for now */
+
+ if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5)
+ {
+ grub_dprintf ("btrfs", "RAID5\n");
+ nparities = 1;
+ }
+ else
+ {
+ grub_dprintf ("btrfs", "RAID6\n");
+ nparities = 2;
+ }
+
+ stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low);
+
+ high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen);
+ grub_divmod64 (high+nstripes-nparities, nstripes, &parity_pos);
+ grub_divmod64 (parity_pos+nparities+stripen, nstripes, &stripen);
+
+ stripe_offset = low + chunk_stripe_length * high;
+ csize = chunk_stripe_length - low;
+
break;
}
default:
--
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
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