Merging upstream version 6.9.2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 316 insertions, 0 deletions

diff --git a/drivers/md/dm-vdo/recovery-journal.h b/drivers/md/dm-vdo/recovery-journal.h
new file mode 100644
index 0000000000..8990711730
--- /dev/null
+++ b/drivers/md/dm-vdo/recovery-journal.h
@@ -0,0 +1,316 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef VDO_RECOVERY_JOURNAL_H
+#define VDO_RECOVERY_JOURNAL_H
+
+#include <linux/list.h>
+
+#include "numeric.h"
+
+#include "admin-state.h"
+#include "constants.h"
+#include "encodings.h"
+#include "flush.h"
+#include "statistics.h"
+#include "types.h"
+#include "wait-queue.h"
+
+/**
+ * DOC: recovery journal.
+ *
+ * The recovery_journal provides a log of all block mapping and reference count changes which have
+ * not yet been stably written to the block map or slab journals. This log helps to reduce the
+ * write amplification of writes by providing amortization of slab journal and block map page
+ * updates.
+ *
+ * The recovery journal has a single dedicated queue and thread for performing all journal updates.
+ * The concurrency guarantees of this single-threaded model allow the code to omit more
+ * fine-grained locking for recovery journal structures.
+ *
+ * The journal consists of a set of on-disk blocks arranged as a circular log with monotonically
+ * increasing sequence numbers. Three sequence numbers serve to define the active extent of the
+ * journal. The 'head' is the oldest active block in the journal. The 'tail' is the end of the
+ * half-open interval containing the active blocks. 'active' is the number of the block actively
+ * receiving entries. In an empty journal, head == active == tail. Once any entries are added, tail
+ * = active + 1, and head may be any value in the interval [tail - size, active].
+ *
+ * The journal also contains a set of in-memory blocks which are used to buffer up entries until
+ * they can be committed. In general the number of in-memory blocks ('tail_buffer_count') will be
+ * less than the on-disk size. Each in-memory block is also a vdo_completion. Each in-memory block
+ * has a vio which is used to commit that block to disk. The vio's data is the on-disk
+ * representation of the journal block. In addition each in-memory block has a buffer which is used
+ * to accumulate entries while a partial commit of the block is in progress. In-memory blocks are
+ * kept on two rings. Free blocks live on the 'free_tail_blocks' ring. When a block becomes active
+ * (see below) it is moved to the 'active_tail_blocks' ring. When a block is fully committed, it is
+ * moved back to the 'free_tail_blocks' ring.
+ *
+ * When entries are added to the journal, they are added to the active in-memory block, as
+ * indicated by the 'active_block' field. If the caller wishes to wait for the entry to be
+ * committed, the requesting VIO will be attached to the in-memory block to which the caller's
+ * entry was added. If the caller does wish to wait, or if the entry filled the active block, an
+ * attempt will be made to commit that block to disk. If there is already another commit in
+ * progress, the attempt will be ignored and then automatically retried when the in-progress commit
+ * completes. If there is no commit in progress, any data_vios waiting on the block are transferred
+ * to the block's vio which is then written, automatically waking all of the waiters when it
+ * completes. When the write completes, any entries which accumulated in the block are copied to
+ * the vio's data buffer.
+ *
+ * Finally, the journal maintains a set of counters, one for each on disk journal block. These
+ * counters are used as locks to prevent premature reaping of journal blocks. Each time a new
+ * sequence number is used, the counter for the corresponding block is incremented. The counter is
+ * subsequently decremented when that block is filled and then committed for the last time. This
+ * prevents blocks from being reaped while they are still being updated. The counter is also
+ * incremented once for each entry added to a block, and decremented once each time the block map
+ * is updated in memory for that request. This prevents blocks from being reaped while their VIOs
+ * are still active. Finally, each in-memory block map page tracks the oldest journal block that
+ * contains entries corresponding to uncommitted updates to that block map page. Each time an
+ * in-memory block map page is updated, it checks if the journal block for the VIO is earlier than
+ * the one it references, in which case it increments the count on the earlier journal block and
+ * decrements the count on the later journal block, maintaining a lock on the oldest journal block
+ * containing entries for that page. When a block map page has been flushed from the cache, the
+ * counter for the journal block it references is decremented. Whenever the counter for the head
+ * block goes to 0, the head is advanced until it comes to a block whose counter is not 0 or until
+ * it reaches the active block. This is the mechanism for reclaiming journal space on disk.
+ *
+ * If there is no in-memory space when a VIO attempts to add an entry, the VIO will be attached to
+ * the 'commit_completion' and will be woken the next time a full block has committed. If there is
+ * no on-disk space when a VIO attempts to add an entry, the VIO will be attached to the
+ * 'reap_completion', and will be woken the next time a journal block is reaped.
+ */
+
+enum vdo_zone_type {
+	VDO_ZONE_TYPE_ADMIN,
+	VDO_ZONE_TYPE_JOURNAL,
+	VDO_ZONE_TYPE_LOGICAL,
+	VDO_ZONE_TYPE_PHYSICAL,
+};
+
+struct lock_counter {
+	/* The completion for notifying the owner of a lock release */
+	struct vdo_completion completion;
+	/* The number of logical zones which may hold locks */
+	zone_count_t logical_zones;
+	/* The number of physical zones which may hold locks */
+	zone_count_t physical_zones;
+	/* The number of locks */
+	block_count_t locks;
+	/* Whether the lock release notification is in flight */
+	atomic_t state;
+	/* The number of logical zones which hold each lock */
+	atomic_t *logical_zone_counts;
+	/* The number of physical zones which hold each lock */
+	atomic_t *physical_zone_counts;
+	/* The per-lock counts for the journal zone */
+	u16 *journal_counters;
+	/* The per-lock decrement counts for the journal zone */
+	atomic_t *journal_decrement_counts;
+	/* The per-zone, per-lock reference counts for logical zones */
+	u16 *logical_counters;
+	/* The per-zone, per-lock reference counts for physical zones */
+	u16 *physical_counters;
+};
+
+struct recovery_journal_block {
+	/* The doubly linked pointers for the free or active lists */
+	struct list_head list_node;
+	/* The waiter for the pending full block list */
+	struct vdo_waiter write_waiter;
+	/* The journal to which this block belongs */
+	struct recovery_journal *journal;
+	/* A pointer to the current sector in the packed block buffer */
+	struct packed_journal_sector *sector;
+	/* The vio for writing this block */
+	struct vio vio;
+	/* The sequence number for this block */
+	sequence_number_t sequence_number;
+	/* The location of this block in the on-disk journal */
+	physical_block_number_t block_number;
+	/* Whether this block is being committed */
+	bool committing;
+	/* The total number of entries in this block */
+	journal_entry_count_t entry_count;
+	/* The total number of uncommitted entries (queued or committing) */
+	journal_entry_count_t uncommitted_entry_count;
+	/* The number of new entries in the current commit */
+	journal_entry_count_t entries_in_commit;
+	/* The queue of vios which will make entries for the next commit */
+	struct vdo_wait_queue entry_waiters;
+	/* The queue of vios waiting for the current commit */
+	struct vdo_wait_queue commit_waiters;
+};
+
+struct recovery_journal {
+	/* The thread ID of the journal zone */
+	thread_id_t thread_id;
+	/* The slab depot which can hold locks on this journal */
+	struct slab_depot *depot;
+	/* The block map which can hold locks on this journal */
+	struct block_map *block_map;
+	/* The queue of vios waiting to make entries */
+	struct vdo_wait_queue entry_waiters;
+	/* The number of free entries in the journal */
+	u64 available_space;
+	/* The number of decrement entries which need to be made */
+	data_vio_count_t pending_decrement_count;
+	/* Whether the journal is adding entries from the increment or decrement waiters queues */
+	bool adding_entries;
+	/* The administrative state of the journal */
+	struct admin_state state;
+	/* Whether a reap is in progress */
+	bool reaping;
+	/* The location of the first journal block */
+	physical_block_number_t origin;
+	/* The oldest active block in the journal on disk for block map rebuild */
+	sequence_number_t block_map_head;
+	/* The oldest active block in the journal on disk for slab journal replay */
+	sequence_number_t slab_journal_head;
+	/* The newest block in the journal on disk to which a write has finished */
+	sequence_number_t last_write_acknowledged;
+	/* The end of the half-open interval of the active journal */
+	sequence_number_t tail;
+	/* The point at which the last entry will have been added */
+	struct journal_point append_point;
+	/* The journal point of the vio most recently released from the journal */
+	struct journal_point commit_point;
+	/* The nonce of the VDO */
+	nonce_t nonce;
+	/* The number of recoveries completed by the VDO */
+	u8 recovery_count;
+	/* The number of entries which fit in a single block */
+	journal_entry_count_t entries_per_block;
+	/* Unused in-memory journal blocks */
+	struct list_head free_tail_blocks;
+	/* In-memory journal blocks with records */
+	struct list_head active_tail_blocks;
+	/* A pointer to the active block (the one we are adding entries to now) */
+	struct recovery_journal_block *active_block;
+	/* Journal blocks that need writing */
+	struct vdo_wait_queue pending_writes;
+	/* The new block map reap head after reaping */
+	sequence_number_t block_map_reap_head;
+	/* The head block number for the block map rebuild range */
+	block_count_t block_map_head_block_number;
+	/* The new slab journal reap head after reaping */
+	sequence_number_t slab_journal_reap_head;
+	/* The head block number for the slab journal replay range */
+	block_count_t slab_journal_head_block_number;
+	/* The data-less vio, usable only for flushing */
+	struct vio *flush_vio;
+	/* The number of blocks in the on-disk journal */
+	block_count_t size;
+	/* The number of logical blocks that are in-use */
+	block_count_t logical_blocks_used;
+	/* The number of block map pages that are allocated */
+	block_count_t block_map_data_blocks;
+	/* The number of journal blocks written but not yet acknowledged */
+	block_count_t pending_write_count;
+	/* The threshold at which slab journal tail blocks will be written out */
+	block_count_t slab_journal_commit_threshold;
+	/* Counters for events in the journal that are reported as statistics */
+	struct recovery_journal_statistics events;
+	/* The locks for each on-disk block */
+	struct lock_counter lock_counter;
+	/* The tail blocks */
+	struct recovery_journal_block blocks[];
+};
+
+/**
+ * vdo_get_recovery_journal_block_number() - Get the physical block number for a given sequence
+ *                                           number.
+ * @journal: The journal.
+ * @sequence: The sequence number of the desired block.
+ *
+ * Return: The block number corresponding to the sequence number.
+ */
+static inline physical_block_number_t __must_check
+vdo_get_recovery_journal_block_number(const struct recovery_journal *journal,
+				      sequence_number_t sequence)
+{
+	/*
+	 * Since journal size is a power of two, the block number modulus can just be extracted
+	 * from the low-order bits of the sequence.
+	 */
+	return vdo_compute_recovery_journal_block_number(journal->size, sequence);
+}
+
+/**
+ * vdo_compute_recovery_journal_check_byte() - Compute the check byte for a given sequence number.
+ * @journal: The journal.
+ * @sequence: The sequence number.
+ *
+ * Return: The check byte corresponding to the sequence number.
+ */
+static inline u8 __must_check
+vdo_compute_recovery_journal_check_byte(const struct recovery_journal *journal,
+					sequence_number_t sequence)
+{
+	/* The check byte must change with each trip around the journal. */
+	return (((sequence / journal->size) & 0x7F) | 0x80);
+}
+
+int __must_check vdo_decode_recovery_journal(struct recovery_journal_state_7_0 state,
+					     nonce_t nonce, struct vdo *vdo,
+					     struct partition *partition,
+					     u64 recovery_count,
+					     block_count_t journal_size,
+					     struct recovery_journal **journal_ptr);
+
+void vdo_free_recovery_journal(struct recovery_journal *journal);
+
+void vdo_initialize_recovery_journal_post_repair(struct recovery_journal *journal,
+						 u64 recovery_count,
+						 sequence_number_t tail,
+						 block_count_t logical_blocks_used,
+						 block_count_t block_map_data_blocks);
+
+block_count_t __must_check
+vdo_get_journal_block_map_data_blocks_used(struct recovery_journal *journal);
+
+thread_id_t __must_check vdo_get_recovery_journal_thread_id(struct recovery_journal *journal);
+
+void vdo_open_recovery_journal(struct recovery_journal *journal,
+			       struct slab_depot *depot, struct block_map *block_map);
+
+sequence_number_t
+vdo_get_recovery_journal_current_sequence_number(struct recovery_journal *journal);
+
+block_count_t __must_check vdo_get_recovery_journal_length(block_count_t journal_size);
+
+struct recovery_journal_state_7_0 __must_check
+vdo_record_recovery_journal(const struct recovery_journal *journal);
+
+void vdo_add_recovery_journal_entry(struct recovery_journal *journal,
+				    struct data_vio *data_vio);
+
+void vdo_acquire_recovery_journal_block_reference(struct recovery_journal *journal,
+						  sequence_number_t sequence_number,
+						  enum vdo_zone_type zone_type,
+						  zone_count_t zone_id);
+
+void vdo_release_recovery_journal_block_reference(struct recovery_journal *journal,
+						  sequence_number_t sequence_number,
+						  enum vdo_zone_type zone_type,
+						  zone_count_t zone_id);
+
+void vdo_release_journal_entry_lock(struct recovery_journal *journal,
+				    sequence_number_t sequence_number);
+
+void vdo_drain_recovery_journal(struct recovery_journal *journal,
+				const struct admin_state_code *operation,
+				struct vdo_completion *parent);
+
+void vdo_resume_recovery_journal(struct recovery_journal *journal,
+				 struct vdo_completion *parent);
+
+block_count_t __must_check
+vdo_get_recovery_journal_logical_blocks_used(const struct recovery_journal *journal);
+
+struct recovery_journal_statistics __must_check
+vdo_get_recovery_journal_statistics(const struct recovery_journal *journal);
+
+void vdo_dump_recovery_journal_statistics(const struct recovery_journal *journal);
+
+#endif /* VDO_RECOVERY_JOURNAL_H */