Please ignore this email On 19/09/2018 20.36, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <[email protected]> > > Signed-off-by: Goffredo Baroncelli <[email protected]> > --- > grub-core/fs/btrfs.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 66 insertions(+) > > diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c > index be195448d..56c42746d 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 +766,70 @@ 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, block_nr, high, 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; > + } > + > + /* > + * A RAID 6 layout consists of several blocks spread on the disks. > + * The raid terminology is used to call all the blocks of a row > + * "stripe". Unfortunately the BTRFS terminology confuses block > + * and stripe. > + * > + * Disk0 Disk1 Disk2 Disk3 > + * > + * A1 B1 P1 Q1 > + * Q2 A2 B2 P2 > + * P3 Q3 A3 B3 > + * [...] > + * > + * Note that the placement of the parities depends on row index. > + * In the code below: > + * - block_nr is the block number without the parities > + * (A1 = 0, B1 = 1, A2 = 2, B2 = 3, ...), > + * - high is the row number (0 for A1...Q1, 1 for Q2...P2, ...), > + * - stripen is the disk number (0 for A1,Q2,P3, 1 for B1...), > + * - off is the logical address to read > + * - chunk_stripe_length is the size of a block (typically 64k), > + * - nstripes is the number of disks, > + * - low is the offset of the data inside a stripe, > + * - stripe_offset is the disk offset, > + * - csize is the "potential" data to read. It will be reduced to > + * size if the latter is smaller. > + */ > + block_nr = grub_divmod64 (off, chunk_stripe_length, &low); > + > + /* > + * stripen is computed without the parities (0 for A1, A2, A3... > + * 1 for B1, B2...). > + */ > + high = grub_divmod64 (block_nr, nstripes - nparities, &stripen); > + > + /* > + * stripen is recomputed considering the parities (0 for A1, 1 for > + * A2, 2 for A3....). > + */ > + grub_divmod64 (high + 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 _______________________________________________ Grub-devel mailing list [email protected] https://lists.gnu.org/mailman/listinfo/grub-devel
