On 2018年07月16日 21:06, David Sterba wrote: > On Mon, Jul 09, 2018 at 02:42:02PM +0800, Qu Wenruo wrote: >> This patch will introduce chunk <-> dev extent mapping check, to protect >> us against invalid dev extents or chunks. >> >> Since chunk mapping is the fundamental infrastructure of btrfs, extra >> check at mount time could prevent a lot of unexpected behavior (BUG_ON). >> >> Reported-by: Xu Wen <wen.xu@xxxxxxxxxx> >> Links: https://bugzilla.kernel.org/show_bug.cgi?id=200403 > > Link: > >> Links: https://bugzilla.kernel.org/show_bug.cgi?id=200407 >> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx> >> --- >> fs/btrfs/disk-io.c | 7 ++ >> fs/btrfs/volumes.c | 173 +++++++++++++++++++++++++++++++++++++++++++++ >> fs/btrfs/volumes.h | 2 + >> 3 files changed, 182 insertions(+) >> >> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c >> index 205092dc9390..068ca7498e94 100644 >> --- a/fs/btrfs/disk-io.c >> +++ b/fs/btrfs/disk-io.c >> @@ -3075,6 +3075,13 @@ int open_ctree(struct super_block *sb, >> fs_info->generation = generation; >> fs_info->last_trans_committed = generation; >> >> + ret = btrfs_verify_dev_extents(fs_info); >> + if (ret) { >> + btrfs_err(fs_info, >> + "failed to verify dev extents against chunks: %d", >> + ret); >> + goto fail_block_groups; >> + } >> ret = btrfs_recover_balance(fs_info); >> if (ret) { >> btrfs_err(fs_info, "failed to recover balance: %d", ret); >> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >> index e6a8e4aabc66..05e418cb37f3 100644 >> --- a/fs/btrfs/volumes.c >> +++ b/fs/btrfs/volumes.c >> @@ -6440,6 +6440,7 @@ static int read_one_chunk(struct btrfs_fs_info *fs_info, struct btrfs_key *key, >> map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk); >> map->type = btrfs_chunk_type(leaf, chunk); >> map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk); >> + map->verified_stripes = 0; >> for (i = 0; i < num_stripes; i++) { >> map->stripes[i].physical = >> btrfs_stripe_offset_nr(leaf, chunk, i); >> @@ -7295,3 +7296,175 @@ void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info) >> fs_devices = fs_devices->seed; >> } >> } >> + >> +static u64 calc_stripe_length(u64 type, u64 chunk_len, int num_stripes) >> +{ >> + switch (type & BTRFS_BLOCK_GROUP_PROFILE_MASK) { >> + case BTRFS_BLOCK_GROUP_RAID0: >> + return div_u64(chunk_len, num_stripes); >> + case BTRFS_BLOCK_GROUP_RAID10: >> + return div_u64(chunk_len * 2, num_stripes); >> + case BTRFS_BLOCK_GROUP_RAID5: >> + return div_u64(chunk_len, num_stripes - 1); >> + case BTRFS_BLOCK_GROUP_RAID6: >> + return div_u64(chunk_len, num_stripes - 2); >> + default: >> + return chunk_len; >> + } >> +} > > There are already too many hardcoded values for the raid profiles, > please don't add another one unless really necessary and use existing > predefined constants or helpers (eg. nr_data_stripes or > btrfs_raid_array). OK, I'll try to reuse btrfs_raid_array in next version. Thanks, Qu > >> +static int verify_one_dev_extent(struct btrfs_fs_info *fs_info, >> + u64 chunk_offset, u64 devid, >> + u64 physical_offset, u64 physical_len) >> +{ >> + struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree; >> + struct extent_map *em; >> + struct map_lookup *map; >> + u64 stripe_len; >> + bool found = false; > > This variable is only set and never checked. > >> + int ret = 0; >> + int i; >> + >> + read_lock(&em_tree->lock); >> + em = lookup_extent_mapping(em_tree, chunk_offset, 1); >> + read_unlock(&em_tree->lock); >> + >> + if (!em) { >> + ret = -EUCLEAN; >> + btrfs_err(fs_info, >> + "dev extent (%llu, %llu) doesn't have corresponding chunk", >> + devid, physical_offset); >> + goto out; >> + } >> + >> + map = em->map_lookup; >> + stripe_len = calc_stripe_length(map->type, em->len, map->num_stripes); >> + if (physical_len != stripe_len) { >> + btrfs_err(fs_info, >> +"dev extent (%llu, %llu) length doesn't match with chunk %llu, have %llu expect %llu", >> + devid, physical_offset, em->start, physical_len, >> + stripe_len); >> + ret = -EUCLEAN; >> + goto out; >> + } >> + >> + for (i = 0; i < map->num_stripes; i++) { >> + if (map->stripes[i].dev->devid == devid && >> + map->stripes[i].physical == physical_offset) { >> + found = true; > > 2nd time set > >> + if (map->verified_stripes >= map->num_stripes) { >> + btrfs_err(fs_info, >> + "too many dev extent for chunk %llu is detected", >> + em->start); >> + ret = -EUCLEAN; >> + goto out; >> + } >> + map->verified_stripes++; >> + break; >> + } >> + } >> +out: >> + free_extent_map(em); >> + return ret; >> +} >> + >> +static int verify_chunk_dev_extent_mapping(struct btrfs_fs_info *fs_info) >> +{ >> + struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree; >> + struct extent_map *em; >> + struct rb_node *node; >> + int ret = 0; >> + >> + read_lock(&em_tree->lock); >> + for (node = rb_first(&em_tree->map); node; node = rb_next(node)) { >> + em = rb_entry(node, struct extent_map, rb_node); >> + if (em->map_lookup->num_stripes != >> + em->map_lookup->verified_stripes) { >> + btrfs_err(fs_info, >> + "chunk %llu has missing dev extent, have %d expect %d", >> + em->start, em->map_lookup->verified_stripes, >> + em->map_lookup->num_stripes); >> + ret = -EUCLEAN; >> + goto out; >> + } >> + } >> +out: >> + read_unlock(&em_tree->lock); >> + return ret; >> +} >> + >> +/* >> + * Ensure all dev extents are mapped to correct chunk. >> + * Or later chunk allocation/free would cause unexpected behavior. >> + * >> + * NOTE: This will iterate through the whole device tree, which should be >> + * at the same size level of chunk tree. >> + * This would increase mount time by a tiny fraction. >> + */ >> +int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info) >> +{ >> + struct btrfs_path *path; >> + struct btrfs_root *root = fs_info->dev_root; >> + struct btrfs_key key; >> + int ret = 0; >> + >> + key.objectid = 1; >> + key.type = BTRFS_DEV_EXTENT_KEY; >> + key.offset = 0; >> + >> + path = btrfs_alloc_path(); >> + if (!path) >> + return -ENOMEM; >> + >> + path->reada = READA_FORWARD; >> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); >> + if (ret < 0) >> + goto out; >> + >> + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { >> + ret = btrfs_next_item(root, path); >> + if (ret < 0) >> + goto out; >> + /* No dev extents at all? Not good */ >> + if (ret > 0) { >> + ret = -EUCLEAN; >> + goto out; >> + } >> + } >> + while (1) { >> + struct extent_buffer *leaf = path->nodes[0]; >> + struct btrfs_dev_extent *dext; >> + int slot = path->slots[0]; >> + u64 chunk_offset; >> + u64 physical_offset; >> + u64 physical_len; >> + u64 devid; >> + >> + btrfs_item_key_to_cpu(leaf, &key, slot); >> + if (key.type != BTRFS_DEV_EXTENT_KEY) >> + break; >> + devid = key.objectid; >> + physical_offset = key.offset; >> + >> + dext = btrfs_item_ptr(leaf, slot, struct btrfs_dev_extent); >> + chunk_offset = btrfs_dev_extent_chunk_offset(leaf, dext); >> + physical_len = btrfs_dev_extent_length(leaf, dext); >> + >> + ret = verify_one_dev_extent(fs_info, chunk_offset, devid, >> + physical_offset, physical_len); >> + if (ret < 0) >> + goto out; >> + ret = btrfs_next_item(root, path); >> + if (ret < 0) >> + goto out; >> + if (ret > 0) { >> + ret = 0; >> + break; >> + } >> + } >> + >> + /* Ensure all chunks have corresponding dev extents */ >> + ret = verify_chunk_dev_extent_mapping(fs_info); >> +out: >> + btrfs_free_path(path); >> + return ret; >> +} >> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h >> index 6d4f38ad9f5c..4301bf2d0534 100644 >> --- a/fs/btrfs/volumes.h >> +++ b/fs/btrfs/volumes.h >> @@ -345,6 +345,7 @@ struct map_lookup { >> u64 stripe_len; >> int num_stripes; >> int sub_stripes; >> + int verified_stripes; /* For mount time dev extent verification */ >> struct btrfs_bio_stripe stripes[]; >> }; >> >> @@ -559,5 +560,6 @@ void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info); >> void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info); >> bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info, >> struct btrfs_device *failing_dev); >> +int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info); >> >> #endif >> -- >> 2.18.0 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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