From: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> commit 06e1e7f4223c98965fb721b4b1e12083cfbe777e upstream. If we can't read a reliable write pointer from a sequential zone fail creating the block group with an I/O error. Also if the read write pointer is beyond the end of the respective zone, fail the creation of the block group on this zone with an I/O error. While this could also happen in real world scenarios with misbehaving drives, this issue addresses a problem uncovered by fstests' test case generic/475. CC: stable@xxxxxxxxxxxxxxx # 5.12+ Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/zoned.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -1204,6 +1204,13 @@ int btrfs_load_block_group_zone_info(str switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) { case 0: /* single */ + if (alloc_offsets[0] == WP_MISSING_DEV) { + btrfs_err(fs_info, + "zoned: cannot recover write pointer for zone %llu", + physical); + ret = -EIO; + goto out; + } cache->alloc_offset = alloc_offsets[0]; break; case BTRFS_BLOCK_GROUP_DUP: @@ -1221,6 +1228,13 @@ int btrfs_load_block_group_zone_info(str } out: + if (cache->alloc_offset > fs_info->zone_size) { + btrfs_err(fs_info, + "zoned: invalid write pointer %llu in block group %llu", + cache->alloc_offset, cache->start); + ret = -EIO; + } + /* An extent is allocated after the write pointer */ if (!ret && num_conventional && last_alloc > cache->alloc_offset) { btrfs_err(fs_info,