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Diffstat (limited to 'src/knot/journal/journal_metadata.h')
| -rw-r--r-- | src/knot/journal/journal_metadata.h | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/src/knot/journal/journal_metadata.h b/src/knot/journal/journal_metadata.h new file mode 100644 index 0000000..246d899 --- /dev/null +++ b/src/knot/journal/journal_metadata.h @@ -0,0 +1,187 @@ +/* Copyright (C) 2020 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#pragma once + +#include "knot/journal/journal_basic.h" + +typedef struct { + uint32_t first_serial; + uint32_t serial_to; + uint32_t flushed_upto; + uint32_t merged_serial; + uint32_t changeset_count; + uint32_t flags; // a bitmap of flags, see enum below + bool _new_zone; // private: if there were no metadata at all previously +} journal_metadata_t; + +enum journal_metadata_flags { + JOURNAL_LAST_FLUSHED_VALID = (1 << 0), // deprecated + JOURNAL_SERIAL_TO_VALID = (1 << 1), + JOURNAL_MERGED_SERIAL_VALID = (1 << 2), +}; + +typedef int (*journals_walk_cb_t)(const knot_dname_t *zone, void *ctx); + +/*! + * \brief Update the computation of DB resources used by each zone. + * + * Because the amount of used space is bigger than sum of changesets' serialized_sizes, + * journal uses a complicated way to compute each zone's used space: there is a metadata + * showing always the previously-inserting zone. Before the next insert, it is computed + * how the total usage of the DB changed during the previous insert (or delete), and the + * usage increase (or decrease) is accounted on the bill of the previous inserter. + * + * \param txn Journal DB transaction. + * \param new_inserter Name of the zone that is going to insert now. Might be NULL if no insert nor delete will be done. + */ +void update_last_inserter(knot_lmdb_txn_t *txn, const knot_dname_t *new_inserter); + +/* \brief Return the journal database usage by given zone. */ +uint64_t journal_get_occupied(knot_lmdb_txn_t *txn, const knot_dname_t *zone); + +/*! + * \brief Load the metadata from DB into structure. + * + * \param txn Journal DB transaction. + * \param zone Zone name. + * \param md Output: metadata structure. + */ +void journal_load_metadata(knot_lmdb_txn_t *txn, const knot_dname_t *zone, journal_metadata_t *md); + +/*! + * \brief Store the metadata from structure into DB. + * + * \param txn Journal DB transaction. + * \param zone Zone name. + * \param md Metadata structure. + */ +void journal_store_metadata(knot_lmdb_txn_t *txn, const knot_dname_t *zone, const journal_metadata_t *md); + +/*! + * \brief Update metadata according to what was deleted. + * + * \param md Metadata structure to be updated. + * \param deleted_upto Serial-to of the last deleted changeset. + * \param deleted_count Number of deleted changesets. + */ +void journal_metadata_after_delete(journal_metadata_t *md, uint32_t deleted_upto, + size_t deleted_count); + +/*! + * \brief Update metadata according to what was merged. + * + * \param md Metadata structure to be updated. + * \param merged_zij True if it was a merge into zone-in-journal. + * \param merged_serial Serial-from of the merged changeset (ignored if 'merged_zij'). + * \param merged_serial_to Serial-to of the merged changeset. + * \param original_serial_to Previous serial-to of the merged changeset before the merge. + */ +void journal_metadata_after_merge(journal_metadata_t *md, bool merged_zij, uint32_t merged_serial, + uint32_t merged_serial_to, uint32_t original_serial_to); + +/*! + * \brief Update metadata according to what was inserted. + * + * \param md Metadata structure to be updated. + * \param serial Serial-from of the inserted changeset. + * \param serial_to Serial-to of the inserted changeset. + */ +void journal_metadata_after_insert(journal_metadata_t *md, uint32_t serial, uint32_t serial_to); + +/*! + * \brief Update metadata according to inserted extra changeset. + * + * \param md Metadata structure to be updated. + * \param serial Serial-from of the inserted changeset. + * \param serial_to Serial-to of the inserted changeset. + */ +void journal_metadata_after_extra(journal_metadata_t *md, uint32_t serial, uint32_t serial_to); + +/*! + * \brief Delete all zone records in a txn that will later write to the same zone. + * + * \note The difference against journal_del_zone(), which purges even metadata, incl "occupied". + * \note This preserves keeping track of space occupied/freed by this zone. + */ +void journal_del_zone_txn(knot_lmdb_txn_t *txn, const knot_dname_t *zone); + +/*! + * \brief Completely delete all journal records belonging to this zone, including metadata. + * + * \param j Journal to be scraped. + * \param check_existence Don't operate if the journal seems not to exist. + * + * \return KNOT_E* + */ +int journal_scrape_with_md(zone_journal_t j, bool check_existence); + +/*! + * \brief Copy all records related to this zone from one journal DB to another. + * + * \param from DB to copy from. + * \param to DB to copy to. + * \param zone Journal zone. + * + * \return KNOT_E* + */ +int journal_copy_with_md(knot_lmdb_db_t *from, knot_lmdb_db_t *to, const knot_dname_t *zone); + +/*! + * \brief Update the metadata stored in journal DB after a zone flush. + * + * \param j Journal to be notified about flush. + * + * \return KNOT_E* + */ +int journal_set_flushed(zone_journal_t j); + +/*! + * \brief Obtain information about the zone's journal from the DB (mostly metadata). + * + * \param j Zone journal. + * \param exists Output: bool if the zone exists in the journal. + * \param first_serial Optional output: serial-from of the first changeset in journal. + * \param has_zij Optional output: bool if there is zone-in-journal. + * \param serial_to Optional output: serial.to of the last changeset in journal. + * \param has_merged Optional output: bool if there is a special (non zone-in-journal) merged changeset. + * \param merged_serial Optional output: serial-from of the merged changeset. + * \param occupied Optional output: DB space occupied by this zones. + * \param occupied_total Optional output: DB space occupied in total by all zones. + * + * \return KNOT_E* + */ +int journal_info(zone_journal_t j, bool *exists, uint32_t *first_serial, bool *has_zij, + uint32_t *serial_to, bool *has_merged, uint32_t *merged_serial, + uint64_t *occupied, uint64_t *occupied_total); + +/*! \brief Return true if this zone exists in journal DB. */ +inline static bool journal_is_existing(zone_journal_t j) { + bool ex = false; + (void)journal_info(j, &ex, NULL, NULL, NULL, NULL, NULL, NULL, NULL); + return ex; +} + +/*! + * \brief Call a function for each zone being in the journal DB. + * + * \param db Journal database. + * \param cb Callback to be called for each zone-name found. + * \param ctx Arbitrary context to be passed to the callback. + * + * \return An error code from either journal operations or from the callback. + */ +int journals_walk(knot_lmdb_db_t *db, journals_walk_cb_t cb, void *ctx); |