From e653d42658033ac636fb8fa846ba08e6dd81c308 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 29 Jan 2016 13:03:25 +0800 Subject: btrfs-progs: convert: Introduce new function to create converted image Use new function, create_convert_image_v2() to create snapshot of old filesystem. Unlike old function which is called after copying all inodes, this function need to be called before copying inodes. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- btrfs-convert.c | 184 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 184 insertions(+) (limited to 'btrfs-convert.c') diff --git a/btrfs-convert.c b/btrfs-convert.c index c826634f..8f589ebb 100644 --- a/btrfs-convert.c +++ b/btrfs-convert.c @@ -1439,6 +1439,7 @@ static int create_image_file_range(struct btrfs_trans_handle *trans, fail: return ret; } + /* * Create the fs image file. */ @@ -1632,6 +1633,189 @@ fail: return ret; } +static int create_image_file_range_v2(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct cache_tree *used, + struct btrfs_inode_item *inode, + u64 ino, u64 bytenr, u64 *ret_len, + int datacsum) +{ + struct cache_extent *cache; + struct btrfs_block_group_cache *bg_cache; + u64 len = *ret_len; + u64 disk_bytenr; + int ret; + + BUG_ON(bytenr != round_down(bytenr, root->sectorsize)); + BUG_ON(len != round_down(len, root->sectorsize)); + len = min_t(u64, len, BTRFS_MAX_EXTENT_SIZE); + + cache = search_cache_extent(used, bytenr); + if (cache) { + if (cache->start <= bytenr) { + /* + * |///////Used///////| + * |<--insert--->| + * bytenr + */ + len = min_t(u64, len, cache->start + cache->size - + bytenr); + disk_bytenr = bytenr; + } else { + /* + * |//Used//| + * |<-insert-->| + * bytenr + */ + len = min(len, cache->start - bytenr); + disk_bytenr = 0; + datacsum = 0; + } + } else { + /* + * |//Used//| |EOF + * |<-insert-->| + * bytenr + */ + disk_bytenr = 0; + datacsum = 0; + } + + if (disk_bytenr) { + /* Check if the range is in a data block group */ + bg_cache = btrfs_lookup_block_group(root->fs_info, bytenr); + if (!bg_cache) + return -ENOENT; + if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_DATA)) + return -EINVAL; + + /* The extent should never cross block group boundary */ + len = min_t(u64, len, bg_cache->key.objectid + + bg_cache->key.offset - bytenr); + } + + BUG_ON(len != round_down(len, root->sectorsize)); + ret = btrfs_record_file_extent(trans, root, ino, inode, bytenr, + disk_bytenr, len); + if (ret < 0) + return ret; + + if (datacsum) + ret = csum_disk_extent(trans, root, bytenr, len); + *ret_len = len; + return ret; +} + +static int wipe_reserved_ranges(struct cache_tree *tree, u64 min_stripe_size, + int ensure_size); + +/* + * Create the fs image file of old filesystem. + * + * This is completely fs independent as we have cctx->used, only + * need to create file extents pointing to all the positions. + * TODO: Add handler for reserved ranges in next patch + */ +static int create_image_v2(struct btrfs_root *root, + struct btrfs_mkfs_config *cfg, + struct btrfs_convert_context *cctx, + u64 size, char *name, int datacsum) +{ + struct btrfs_inode_item buf; + struct btrfs_trans_handle *trans; + struct btrfs_path *path = NULL; + struct btrfs_key key; + struct cache_extent *cache; + struct cache_tree used_tmp; + u64 cur; + u64 ino; + int ret; + + trans = btrfs_start_transaction(root, 1); + if (!trans) + return -ENOMEM; + + cache_tree_init(&used_tmp); + + ret = btrfs_find_free_objectid(trans, root, BTRFS_FIRST_FREE_OBJECTID, + &ino); + if (ret < 0) + goto out; + ret = btrfs_new_inode(trans, root, ino, 0600 | S_IFREG); + if (ret < 0) + goto out; + ret = btrfs_add_link(trans, root, ino, BTRFS_FIRST_FREE_OBJECTID, name, + strlen(name), BTRFS_FT_REG_FILE, NULL, 1); + if (ret < 0) + goto out; + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + key.objectid = ino; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret) { + ret = (ret > 0 ? -ENOENT : ret); + goto out; + } + read_extent_buffer(path->nodes[0], &buf, + btrfs_item_ptr_offset(path->nodes[0], path->slots[0]), + sizeof(buf)); + btrfs_release_path(path); + + /* + * Create a new used space cache, which doesn't contain the reserved + * range + */ + for (cache = first_cache_extent(&cctx->used); cache; + cache = next_cache_extent(cache)) { + ret = add_cache_extent(&used_tmp, cache->start, cache->size); + if (ret < 0) + goto out; + } + ret = wipe_reserved_ranges(&used_tmp, 0, 0); + if (ret < 0) + goto out; + + /* + * Start from 1M, as 0~1M is reserved, and create_image_file_range_v2() + * can't handle bytenr 0(will consider it as a hole) + */ + cur = 1024 * 1024; + while (cur < size) { + u64 len = size - cur; + + ret = create_image_file_range_v2(trans, root, &used_tmp, + &buf, ino, cur, &len, datacsum); + if (ret < 0) + goto out; + cur += len; + } + + key.objectid = ino; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret) { + ret = (ret > 0 ? -ENOENT : ret); + goto out; + } + btrfs_set_stack_inode_size(&buf, cfg->num_bytes); + write_extent_buffer(path->nodes[0], &buf, + btrfs_item_ptr_offset(path->nodes[0], path->slots[0]), + sizeof(buf)); +out: + free_extent_cache_tree(&used_tmp); + btrfs_free_path(path); + btrfs_commit_transaction(trans, root); + return ret; +} + static struct btrfs_root * link_subvol(struct btrfs_root *root, const char *base, u64 root_objectid) { -- cgit v1.2.3