| From 8ca7cab82bda4eb0b8064befeeeaa38106cac637 Mon Sep 17 00:00:00 2001 |
| From: Jaegeuk Kim <jaegeuk@google.com> |
| Date: Wed, 14 Apr 2021 08:28:28 -0700 |
| Subject: dm verity fec: fix misaligned RS roots IO |
| |
| From: Jaegeuk Kim <jaegeuk@google.com> |
| |
| commit 8ca7cab82bda4eb0b8064befeeeaa38106cac637 upstream. |
| |
| commit df7b59ba9245 ("dm verity: fix FEC for RS roots unaligned to |
| block size") introduced the possibility for misaligned roots IO |
| relative to the underlying device's logical block size. E.g. Android's |
| default RS roots=2 results in dm_bufio->block_size=1024, which causes |
| the following EIO if the logical block size of the device is 4096, |
| given v->data_dev_block_bits=12: |
| |
| E sd 0 : 0:0:0: [sda] tag#30 request not aligned to the logical block size |
| E blk_update_request: I/O error, dev sda, sector 10368424 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0 |
| E device-mapper: verity-fec: 254:8: FEC 9244672: parity read failed (block 18056): -5 |
| |
| Fix this by onlu using f->roots for dm_bufio blocksize IFF it is |
| aligned to v->data_dev_block_bits. |
| |
| Fixes: df7b59ba9245 ("dm verity: fix FEC for RS roots unaligned to block size") |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Jaegeuk Kim <jaegeuk@google.com> |
| Signed-off-by: Mike Snitzer <snitzer@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/md/dm-verity-fec.c | 11 ++++++++--- |
| drivers/md/dm-verity-fec.h | 1 + |
| 2 files changed, 9 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/md/dm-verity-fec.c |
| +++ b/drivers/md/dm-verity-fec.c |
| @@ -65,7 +65,7 @@ static u8 *fec_read_parity(struct dm_ver |
| u8 *res; |
| |
| position = (index + rsb) * v->fec->roots; |
| - block = div64_u64_rem(position, v->fec->roots << SECTOR_SHIFT, &rem); |
| + block = div64_u64_rem(position, v->fec->io_size, &rem); |
| *offset = (unsigned)rem; |
| |
| res = dm_bufio_read(v->fec->bufio, block, buf); |
| @@ -154,7 +154,7 @@ static int fec_decode_bufs(struct dm_ver |
| |
| /* read the next block when we run out of parity bytes */ |
| offset += v->fec->roots; |
| - if (offset >= v->fec->roots << SECTOR_SHIFT) { |
| + if (offset >= v->fec->io_size) { |
| dm_bufio_release(buf); |
| |
| par = fec_read_parity(v, rsb, block_offset, &offset, &buf); |
| @@ -742,8 +742,13 @@ int verity_fec_ctr(struct dm_verity *v) |
| return -E2BIG; |
| } |
| |
| + if ((f->roots << SECTOR_SHIFT) & ((1 << v->data_dev_block_bits) - 1)) |
| + f->io_size = 1 << v->data_dev_block_bits; |
| + else |
| + f->io_size = v->fec->roots << SECTOR_SHIFT; |
| + |
| f->bufio = dm_bufio_client_create(f->dev->bdev, |
| - f->roots << SECTOR_SHIFT, |
| + f->io_size, |
| 1, 0, NULL, NULL); |
| if (IS_ERR(f->bufio)) { |
| ti->error = "Cannot initialize FEC bufio client"; |
| --- a/drivers/md/dm-verity-fec.h |
| +++ b/drivers/md/dm-verity-fec.h |
| @@ -36,6 +36,7 @@ struct dm_verity_fec { |
| struct dm_dev *dev; /* parity data device */ |
| struct dm_bufio_client *data_bufio; /* for data dev access */ |
| struct dm_bufio_client *bufio; /* for parity data access */ |
| + size_t io_size; /* IO size for roots */ |
| sector_t start; /* parity data start in blocks */ |
| sector_t blocks; /* number of blocks covered */ |
| sector_t rounds; /* number of interleaving rounds */ |