| Message ID | 20181011185103.23146-10-kreijack@libero.it (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. | expand |
On Thu, Oct 11, 2018 at 08:51:03PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Add the RAID 6 recovery, in order to use a RAID 6 filesystem even if some > disks (up to two) are missing. This code use the md RAID 6 code already > present in grub. > > Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> > Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> > --- > grub-core/fs/btrfs.c | 60 +++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 54 insertions(+), 6 deletions(-) > > diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c > index d066d54cc..d20ee09e4 100644 > --- a/grub-core/fs/btrfs.c > +++ b/grub-core/fs/btrfs.c > @@ -30,6 +30,7 @@ > #include <grub/i18n.h> > #include <grub/btrfs.h> > #include <grub/crypto.h> > +#include <grub/diskfilter.h> > > GRUB_MOD_LICENSE ("GPLv3+"); > > @@ -702,11 +703,36 @@ rebuild_raid5 (char *dest, struct raid56_buffer *buffers, > } > } > > +static grub_err_t > +raid6_recover_read_buffer (void *data, int disk_nr, > + grub_uint64_t addr __attribute__ ((unused)), > + void *dest, grub_size_t size) > +{ > + struct raid56_buffer *buffers = data; > + > + if (!buffers[disk_nr].data_is_valid) > + return grub_errno = GRUB_ERR_READ_ERROR; > + > + grub_memcpy(dest, buffers[disk_nr].buf, size); > + > + return grub_errno = GRUB_ERR_NONE; > +} > + > +static void > +rebuild_raid6 (struct raid56_buffer *buffers, grub_uint64_t nstripes, > + grub_uint64_t csize, grub_uint64_t parities_pos, void *dest, > + grub_uint64_t stripen) > + > +{ > + grub_raid6_recover_gen (buffers, nstripes, stripen, parities_pos, > + dest, 0, csize, 0, raid6_recover_read_buffer); > +} > + > 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) > + grub_uint64_t stripe_offset, grub_uint64_t stripen, > + grub_uint64_t csize, void *buf, grub_uint64_t parities_pos) > { > struct raid56_buffer *buffers; > grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes); > @@ -779,6 +805,15 @@ raid56_read_retry (struct grub_btrfs_data *data, > ret = GRUB_ERR_READ_ERROR; > goto cleanup; > } > + else if (failed_devices > 2 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID6)) > + { > + grub_dprintf ("btrfs", > + "not enough disks for raid6: total %" PRIuGRUB_UINT64_T s/not enough disks for raid6/not enough disks for RAID 6/ You are using "RAID 5" in earlier patch, so, please be consistent and use "RAID 6" here. > + ", 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 %" > @@ -789,7 +824,7 @@ raid56_read_retry (struct grub_btrfs_data *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"); > + rebuild_raid6 (buffers, nstripes, csize, parities_pos, buf, stripen); > > ret = GRUB_ERR_NONE; > cleanup: > @@ -879,9 +914,11 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > unsigned redundancy = 1; > unsigned i, j; > int is_raid56; > + grub_uint64_t parities_pos = 0; > > - is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & > - GRUB_BTRFS_CHUNK_TYPE_RAID5); > + is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & > + (GRUB_BTRFS_CHUNK_TYPE_RAID5 | > + GRUB_BTRFS_CHUNK_TYPE_RAID6)); > > if (grub_le_to_cpu64 (chunk->size) <= off) > { > @@ -1030,6 +1067,17 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > */ > grub_divmod64 (high + stripen, nstripes, &stripen); > > + /* > + * parities_pos is equal to "(high - nparities) % nstripes" > + * (see the diagram above). > + * However "high - nparities" might be negative (eg when high > + * == 0) leading to an incorrect computation. However, "high - nparities" can be negative, eg. when high == 0, leading to an incorrect results. > + * Instead "high + nstripes - nparities" is always positive and > + * in modulo nstripes is equal to "(high - nparities) % nstripes" "high + nstripes - nparities" is always positive and modulo nstripes is equal to "(high - nparities) % nstripes". If you change above mentioned things you can retain my Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> Daniel
diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index d066d54cc..d20ee09e4 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -30,6 +30,7 @@ #include <grub/i18n.h> #include <grub/btrfs.h> #include <grub/crypto.h> +#include <grub/diskfilter.h> GRUB_MOD_LICENSE ("GPLv3+"); @@ -702,11 +703,36 @@ rebuild_raid5 (char *dest, struct raid56_buffer *buffers, } } +static grub_err_t +raid6_recover_read_buffer (void *data, int disk_nr, + grub_uint64_t addr __attribute__ ((unused)), + void *dest, grub_size_t size) +{ + struct raid56_buffer *buffers = data; + + if (!buffers[disk_nr].data_is_valid) + return grub_errno = GRUB_ERR_READ_ERROR; + + grub_memcpy(dest, buffers[disk_nr].buf, size); + + return grub_errno = GRUB_ERR_NONE; +} + +static void +rebuild_raid6 (struct raid56_buffer *buffers, grub_uint64_t nstripes, + grub_uint64_t csize, grub_uint64_t parities_pos, void *dest, + grub_uint64_t stripen) + +{ + grub_raid6_recover_gen (buffers, nstripes, stripen, parities_pos, + dest, 0, csize, 0, raid6_recover_read_buffer); +} + 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) + grub_uint64_t stripe_offset, grub_uint64_t stripen, + grub_uint64_t csize, void *buf, grub_uint64_t parities_pos) { struct raid56_buffer *buffers; grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes); @@ -779,6 +805,15 @@ raid56_read_retry (struct grub_btrfs_data *data, ret = GRUB_ERR_READ_ERROR; goto cleanup; } + else if (failed_devices > 2 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID6)) + { + grub_dprintf ("btrfs", + "not enough disks for raid6: 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 %" @@ -789,7 +824,7 @@ raid56_read_retry (struct grub_btrfs_data *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"); + rebuild_raid6 (buffers, nstripes, csize, parities_pos, buf, stripen); ret = GRUB_ERR_NONE; cleanup: @@ -879,9 +914,11 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, unsigned redundancy = 1; unsigned i, j; int is_raid56; + grub_uint64_t parities_pos = 0; - is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & - GRUB_BTRFS_CHUNK_TYPE_RAID5); + is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & + (GRUB_BTRFS_CHUNK_TYPE_RAID5 | + GRUB_BTRFS_CHUNK_TYPE_RAID6)); if (grub_le_to_cpu64 (chunk->size) <= off) { @@ -1030,6 +1067,17 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, */ grub_divmod64 (high + stripen, nstripes, &stripen); + /* + * parities_pos is equal to "(high - nparities) % nstripes" + * (see the diagram above). + * However "high - nparities" might be negative (eg when high + * == 0) leading to an incorrect computation. + * Instead "high + nstripes - nparities" is always positive and + * in modulo nstripes is equal to "(high - nparities) % nstripes" + */ + grub_divmod64 (high + nstripes - nparities, nstripes, + &parities_pos); + stripe_offset = low + chunk_stripe_length * high; csize = chunk_stripe_length - low; @@ -1081,7 +1129,7 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, grub_errno = GRUB_ERR_NONE; if (err) err = raid56_read_retry (data, chunk, stripe_offset, - csize, buf); + stripen, csize, buf, parities_pos); } if (!err) break;