On Thu, Sep 27, 2018 at 08:35:02PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreij...@inwind.it> > > 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 <kreij...@inwind.it> > --- > 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