From d3cf350e21d12790446779fbfb19d22e9aa0bec0 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 26 Jul 2024 16:59:10 +0930 Subject: [PATCH] btrfs-progs: introduce btrfs_rebuild_uuid_tree() for mkfs and btrfs-convert Currently mkfs uses its own create_uuid_tree(), but that function is only handling FS_TREE. This means for btrfs-convert we do not generate the uuid tree, nor add the UUID of the image subvolume. This can be a problem if we're going to support multiple subvolumes during mkfs time. To address this, introduce a new helper, btrfs_rebuild_uuid_tree(): - Create a new uuid tree if there is not one - Remove all the existing items from uuid tree - Iterate through all subvolumes * If the subvolume has no valid UUID, regenerate one * Add the uuid entry for the subvolume UUID * If the subvolume has received UUID, also add it to UUID tree By this, this new helper can handle all the uuid tree generation needs for: - Current mkfs Only one uuid entry for FS_TREE - Current btrfs-convert Only FS_TREE and the image subvolume - Future multi-subvolume mkfs As we do the scan for all subvolumes. - Future "btrfs rescue rebuild-uuid-tree" Signed-off-by: Qu Wenruo --- common/root-tree-utils.c | 278 +++++++++++++++++++++++++++++++++++++++ common/root-tree-utils.h | 1 + convert/main.c | 5 + mkfs/main.c | 37 +----- 4 files changed, 287 insertions(+), 34 deletions(-) diff --git a/common/root-tree-utils.c b/common/root-tree-utils.c index 6a57c51a..09b9ada0 100644 --- a/common/root-tree-utils.c +++ b/common/root-tree-utils.c @@ -15,9 +15,11 @@ */ #include +#include #include "common/root-tree-utils.h" #include "common/messages.h" #include "kernel-shared/disk-io.h" +#include "kernel-shared/uuid-tree.h" int btrfs_make_root_dir(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 objectid) @@ -212,3 +214,279 @@ abort: btrfs_abort_transaction(trans, ret); return ret; } + +static int remove_all_tree_items(struct btrfs_root *root) +{ + struct btrfs_trans_handle *trans; + struct btrfs_path path = { 0 }; + struct btrfs_key key = { 0 }; + int ret; + + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + errno = -ret; + error_msg(ERROR_MSG_START_TRANS, + "remove all items for tree %lld: %m", + root->root_key.objectid); + return ret; + } + while (true) { + int nr_items; + + ret = btrfs_search_slot(trans, root, &key, &path, -1, 1); + if (ret < 0) { + errno = -ret; + error("failed to locate the first key of root %lld: %m", + root->root_key.objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + if (ret == 0) { + ret = -EUCLEAN; + errno = -ret; + error("unexpected all zero key found in root %lld", + root->root_key.objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + nr_items = btrfs_header_nritems(path.nodes[0]); + /* The tree is empty. */ + if (nr_items == 0) { + btrfs_release_path(&path); + break; + } + ret = btrfs_del_items(trans, root, &path, 0, nr_items); + btrfs_release_path(&path); + if (ret < 0) { + errno = -ret; + error("failed to empty the first leaf of root %lld: %m", + root->root_key.objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + } + ret = btrfs_commit_transaction(trans, root); + if (ret < 0) { + errno = -ret; + error_msg(ERROR_MSG_COMMIT_TRANS, + "removal all items for tree %lld: %m", + root->root_key.objectid); + } + return ret; +} + +static int rescan_subvol_uuid(struct btrfs_trans_handle *trans, + struct btrfs_key *subvol_key) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *subvol; + int ret; + + UASSERT(is_fstree(subvol_key->objectid)); + + /* + * Read out the subvolume root and updates root::root_item. + * This is to avoid de-sync between in-memory and on-disk root_items. + */ + subvol = btrfs_read_fs_root(fs_info, subvol_key); + if (IS_ERR(subvol)) { + ret = PTR_ERR(subvol); + error("failed to read subvolume %llu: %m", + subvol_key->objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + /* The uuid is not set, regenerate one. */ + if (uuid_is_null(subvol->root_item.uuid)) { + uuid_generate(subvol->root_item.uuid); + ret = btrfs_update_root(trans, fs_info->tree_root, &subvol->root_key, + &subvol->root_item); + if (ret < 0) { + error("failed to update subvolume %llu: %m", + subvol_key->objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + } + ret = btrfs_uuid_tree_add(trans, subvol->root_item.uuid, + BTRFS_UUID_KEY_SUBVOL, + subvol->root_key.objectid); + if (ret < 0) { + errno = -ret; + error("failed to add uuid for subvolume %llu: %m", + subvol_key->objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + if (!uuid_is_null(subvol->root_item.received_uuid)) { + ret = btrfs_uuid_tree_add(trans, subvol->root_item.uuid, + BTRFS_UUID_KEY_RECEIVED_SUBVOL, + subvol->root_key.objectid); + if (ret < 0) { + errno = -ret; + error("failed to add received_uuid for subvol %llu: %m", + subvol->root_key.objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + } + return 0; +} + +static int rescan_uuid_tree(struct btrfs_fs_info *fs_info) +{ + struct btrfs_root *tree_root = fs_info->tree_root; + struct btrfs_root *uuid_root = fs_info->uuid_root; + struct btrfs_trans_handle *trans; + struct btrfs_path path = { 0 }; + struct btrfs_key key = { 0 }; + int ret; + + UASSERT(uuid_root); + trans = btrfs_start_transaction(uuid_root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + errno = -ret; + error_msg(ERROR_MSG_START_TRANS, "rescan uuid tree: %m"); + return ret; + } + key.objectid = BTRFS_LAST_FREE_OBJECTID; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = (u64)-1; + /* Iterate through all subvolumes except fs tree. */ + while (true) { + struct btrfs_key found_key; + struct extent_buffer *leaf; + int slot; + + /* No more subvolume. */ + if (key.objectid < BTRFS_FIRST_FREE_OBJECTID) { + ret = 0; + break; + } + ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0); + if (ret < 0) { + errno = -ret; + error_msg(ERROR_MSG_READ, "iterate subvolumes: %m"); + btrfs_abort_transaction(trans, ret); + return ret; + } + if (ret > 0) { + ret = btrfs_previous_item(tree_root, &path, + BTRFS_FIRST_FREE_OBJECTID, + BTRFS_ROOT_ITEM_KEY); + if (ret < 0) { + errno = -ret; + btrfs_release_path(&path); + error_msg(ERROR_MSG_READ, "iterate subvolumes: %m"); + btrfs_abort_transaction(trans, ret); + return ret; + } + /* No more subvolume. */ + if (ret > 0) { + ret = 0; + btrfs_release_path(&path); + break; + } + } + leaf = path.nodes[0]; + slot = path.slots[0]; + btrfs_item_key_to_cpu(leaf, &found_key, slot); + btrfs_release_path(&path); + key.objectid = found_key.objectid - 1; + + ret = rescan_subvol_uuid(trans, &found_key); + if (ret < 0) { + errno = -ret; + error("failed to rescan the uuid of subvolume %llu: %m", + found_key.objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + } + + /* Update fs tree uuid. */ + key.objectid = BTRFS_FS_TREE_OBJECTID; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = 0; + ret = rescan_subvol_uuid(trans, &key); + if (ret < 0) { + errno = -ret; + error("failed to rescan the uuid of subvolume %llu: %m", + key.objectid); + btrfs_abort_transaction(trans, ret); + return ret; + } + ret = btrfs_commit_transaction(trans, uuid_root); + if (ret < 0) { + errno = -ret; + error_msg(ERROR_MSG_COMMIT_TRANS, "rescan uuid tree: %m"); + } + return ret; +} + +/* + * Rebuild the whole uuid tree. + * + * If no uuid tree is present, create a new one. + * If there is an existing uuid tree, all items will be deleted first. + * + * For all existing subvolumes (except fs tree), any uninitialized uuid + * (all zero) will be generated using a random uuid, and inserted into the new + * tree. + * And if a subvolume has its UUID initialized, it will not be touched and + * added to the new uuid tree. + */ +int btrfs_rebuild_uuid_tree(struct btrfs_fs_info *fs_info) +{ + struct btrfs_root *uuid_root; + struct btrfs_key key; + int ret; + + if (!fs_info->uuid_root) { + struct btrfs_trans_handle *trans; + + trans = btrfs_start_transaction(fs_info->tree_root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + errno = -ret; + error_msg(ERROR_MSG_START_TRANS, "create uuid tree: %m"); + return ret; + } + key.objectid = BTRFS_UUID_TREE_OBJECTID; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = 0; + uuid_root = btrfs_create_tree(trans, &key); + if (IS_ERR(uuid_root)) { + ret = PTR_ERR(uuid_root); + errno = -ret; + error("failed to create uuid root: %m"); + btrfs_abort_transaction(trans, ret); + return ret; + } + add_root_to_dirty_list(uuid_root); + fs_info->uuid_root = uuid_root; + ret = btrfs_commit_transaction(trans, fs_info->tree_root); + if (ret < 0) { + errno = -ret; + error_msg(ERROR_MSG_COMMIT_TRANS, "create uuid tree: %m"); + return ret; + } + } else { + ret = remove_all_tree_items(fs_info->uuid_root); + if (ret < 0) { + errno = -ret; + error("failed to clear the existing uuid tree: %m"); + return ret; + } + } + UASSERT(fs_info->uuid_root); + ret = rescan_uuid_tree(fs_info); + if (ret < 0) { + errno = -ret; + error("failed to rescan the uuid tree: %m"); + return ret; + } + return 0; +} diff --git a/common/root-tree-utils.h b/common/root-tree-utils.h index 0c4ece24..3cb50802 100644 --- a/common/root-tree-utils.h +++ b/common/root-tree-utils.h @@ -26,5 +26,6 @@ int btrfs_link_subvolume(struct btrfs_trans_handle *trans, struct btrfs_root *parent_root, u64 parent_dir, const char *name, int namelen, struct btrfs_root *subvol); +int btrfs_rebuild_uuid_tree(struct btrfs_fs_info *fs_info); #endif diff --git a/convert/main.c b/convert/main.c index 078ef64e..aa253781 100644 --- a/convert/main.c +++ b/convert/main.c @@ -1339,6 +1339,11 @@ static int do_convert(const char *devname, u32 convert_flags, u32 nodesize, goto fail; } + ret = btrfs_rebuild_uuid_tree(image_root->fs_info); + if (ret < 0) { + errno = -ret; + goto fail; + } memset(root->fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE); if (convert_flags & CONVERT_FLAG_COPY_LABEL) { strncpy_null(root->fs_info->super_copy->label, cctx.label, BTRFS_LABEL_SIZE); diff --git a/mkfs/main.c b/mkfs/main.c index b95f1c33..00ccac14 100644 --- a/mkfs/main.c +++ b/mkfs/main.c @@ -736,35 +736,6 @@ static void update_chunk_allocation(struct btrfs_fs_info *fs_info, } } -static int create_uuid_tree(struct btrfs_trans_handle *trans) -{ - struct btrfs_fs_info *fs_info = trans->fs_info; - struct btrfs_root *root; - struct btrfs_key key = { - .objectid = BTRFS_UUID_TREE_OBJECTID, - .type = BTRFS_ROOT_ITEM_KEY, - }; - int ret = 0; - - UASSERT(fs_info->uuid_root == NULL); - root = btrfs_create_tree(trans, &key); - if (IS_ERR(root)) { - ret = PTR_ERR(root); - goto out; - } - - add_root_to_dirty_list(root); - fs_info->uuid_root = root; - ret = btrfs_uuid_tree_add(trans, fs_info->fs_root->root_item.uuid, - BTRFS_UUID_KEY_SUBVOL, - fs_info->fs_root->root_key.objectid); - if (ret < 0) - btrfs_abort_transaction(trans, ret); - -out: - return ret; -} - static int create_global_root(struct btrfs_trans_handle *trans, u64 objectid, int root_id) { @@ -1822,17 +1793,15 @@ raid_groups: goto out; } - ret = create_uuid_tree(trans); - if (ret) - warning( - "unable to create uuid tree, will be created after mount: %d", ret); - ret = btrfs_commit_transaction(trans, root); if (ret) { errno = -ret; error_msg(ERROR_MSG_START_TRANS, "%m"); goto out; } + ret = btrfs_rebuild_uuid_tree(fs_info); + if (ret < 0) + goto out; ret = cleanup_temp_chunks(fs_info, &allocation, data_profile, metadata_profile, metadata_profile);