1 files changed, 329 insertions, 0 deletions
diff --git a/c_src/libbcachefs/journal_types.h b/c_src/libbcachefs/journal_types.h
new file mode 100644
index 00000000..38817c7a
--- /dev/null
+++ b/c_src/libbcachefs/journal_types.h
@@ -0,0 +1,329 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_JOURNAL_TYPES_H
+#define _BCACHEFS_JOURNAL_TYPES_H
+
+#include <linux/cache.h>
+#include <linux/workqueue.h>
+
+#include "alloc_types.h"
+#include "super_types.h"
+#include "fifo.h"
+
+#define JOURNAL_BUF_BITS	2
+#define JOURNAL_BUF_NR		(1U << JOURNAL_BUF_BITS)
+#define JOURNAL_BUF_MASK	(JOURNAL_BUF_NR - 1)
+
+/*
+ * We put JOURNAL_BUF_NR of these in struct journal; we used them for writes to
+ * the journal that are being staged or in flight.
+ */
+struct journal_buf {
+	struct jset		*data;
+
+	__BKEY_PADDED(key, BCH_REPLICAS_MAX);
+	struct bch_devs_list	devs_written;
+
+	struct closure_waitlist	wait;
+	u64			last_seq;	/* copy of data->last_seq */
+	long			expires;
+	u64			flush_time;
+
+	unsigned		buf_size;	/* size in bytes of @data */
+	unsigned		sectors;	/* maximum size for current entry */
+	unsigned		disk_sectors;	/* maximum size entry could have been, if
+						   buf_size was bigger */
+	unsigned		u64s_reserved;
+	bool			noflush;	/* write has already been kicked off, and was noflush */
+	bool			must_flush;	/* something wants a flush */
+	bool			separate_flush;
+	bool			need_flush_to_write_buffer;
+};
+
+/*
+ * Something that makes a journal entry dirty - i.e. a btree node that has to be
+ * flushed:
+ */
+
+enum journal_pin_type {
+	JOURNAL_PIN_btree,
+	JOURNAL_PIN_key_cache,
+	JOURNAL_PIN_other,
+	JOURNAL_PIN_NR,
+};
+
+struct journal_entry_pin_list {
+	struct list_head		list[JOURNAL_PIN_NR];
+	struct list_head		flushed;
+	atomic_t			count;
+	struct bch_devs_list		devs;
+};
+
+struct journal;
+struct journal_entry_pin;
+typedef int (*journal_pin_flush_fn)(struct journal *j,
+				struct journal_entry_pin *, u64);
+
+struct journal_entry_pin {
+	struct list_head		list;
+	journal_pin_flush_fn		flush;
+	u64				seq;
+};
+
+struct journal_res {
+	bool			ref;
+	u8			idx;
+	u16			u64s;
+	u32			offset;
+	u64			seq;
+};
+
+union journal_res_state {
+	struct {
+		atomic64_t	counter;
+	};
+
+	struct {
+		u64		v;
+	};
+
+	struct {
+		u64		cur_entry_offset:20,
+				idx:2,
+				unwritten_idx:2,
+				buf0_count:10,
+				buf1_count:10,
+				buf2_count:10,
+				buf3_count:10;
+	};
+};
+
+/* bytes: */
+#define JOURNAL_ENTRY_SIZE_MIN		(64U << 10) /* 64k */
+#define JOURNAL_ENTRY_SIZE_MAX		(4U  << 20) /* 4M */
+
+/*
+ * We stash some journal state as sentinal values in cur_entry_offset:
+ * note - cur_entry_offset is in units of u64s
+ */
+#define JOURNAL_ENTRY_OFFSET_MAX	((1U << 20) - 1)
+
+#define JOURNAL_ENTRY_CLOSED_VAL	(JOURNAL_ENTRY_OFFSET_MAX - 1)
+#define JOURNAL_ENTRY_ERROR_VAL		(JOURNAL_ENTRY_OFFSET_MAX)
+
+struct journal_space {
+	/* Units of 512 bytes sectors: */
+	unsigned	next_entry; /* How big the next journal entry can be */
+	unsigned	total;
+};
+
+enum journal_space_from {
+	journal_space_discarded,
+	journal_space_clean_ondisk,
+	journal_space_clean,
+	journal_space_total,
+	journal_space_nr,
+};
+
+enum journal_flags {
+	JOURNAL_REPLAY_DONE,
+	JOURNAL_STARTED,
+	JOURNAL_MAY_SKIP_FLUSH,
+	JOURNAL_NEED_FLUSH_WRITE,
+};
+
+/* Reasons we may fail to get a journal reservation: */
+#define JOURNAL_ERRORS()		\
+	x(ok)				\
+	x(blocked)			\
+	x(max_in_flight)		\
+	x(journal_full)			\
+	x(journal_pin_full)		\
+	x(journal_stuck)		\
+	x(insufficient_devices)
+
+enum journal_errors {
+#define x(n)	JOURNAL_ERR_##n,
+	JOURNAL_ERRORS()
+#undef x
+};
+
+typedef DARRAY(u64)		darray_u64;
+
+/* Embedded in struct bch_fs */
+struct journal {
+	/* Fastpath stuff up front: */
+	struct {
+
+	union journal_res_state reservations;
+	enum bch_watermark	watermark;
+
+	} __aligned(SMP_CACHE_BYTES);
+
+	unsigned long		flags;
+
+	/* Max size of current journal entry */
+	unsigned		cur_entry_u64s;
+	unsigned		cur_entry_sectors;
+
+	/* Reserved space in journal entry to be used just prior to write */
+	unsigned		entry_u64s_reserved;
+
+
+	/*
+	 * 0, or -ENOSPC if waiting on journal reclaim, or -EROFS if
+	 * insufficient devices:
+	 */
+	enum journal_errors	cur_entry_error;
+
+	unsigned		buf_size_want;
+	/*
+	 * We may queue up some things to be journalled (log messages) before
+	 * the journal has actually started - stash them here:
+	 */
+	darray_u64		early_journal_entries;
+
+	/*
+	 * Protects journal_buf->data, when accessing without a jorunal
+	 * reservation: for synchronization between the btree write buffer code
+	 * and the journal write path:
+	 */
+	struct mutex		buf_lock;
+	/*
+	 * Two journal entries -- one is currently open for new entries, the
+	 * other is possibly being written out.
+	 */
+	struct journal_buf	buf[JOURNAL_BUF_NR];
+
+	spinlock_t		lock;
+
+	/* if nonzero, we may not open a new journal entry: */
+	unsigned		blocked;
+
+	/* Used when waiting because the journal was full */
+	wait_queue_head_t	wait;
+	struct closure_waitlist	async_wait;
+
+	struct closure		io;
+	struct delayed_work	write_work;
+
+	/* Sequence number of most recent journal entry (last entry in @pin) */
+	atomic64_t		seq;
+
+	/* seq, last_seq from the most recent journal entry successfully written */
+	u64			seq_ondisk;
+	u64			flushed_seq_ondisk;
+	u64			last_seq_ondisk;
+	u64			err_seq;
+	u64			last_empty_seq;
+
+	/*
+	 * FIFO of journal entries whose btree updates have not yet been
+	 * written out.
+	 *
+	 * Each entry is a reference count. The position in the FIFO is the
+	 * entry's sequence number relative to @seq.
+	 *
+	 * The journal entry itself holds a reference count, put when the
+	 * journal entry is written out. Each btree node modified by the journal
+	 * entry also holds a reference count, put when the btree node is
+	 * written.
+	 *
+	 * When a reference count reaches zero, the journal entry is no longer
+	 * needed. When all journal entries in the oldest journal bucket are no
+	 * longer needed, the bucket can be discarded and reused.
+	 */
+	struct {
+		u64 front, back, size, mask;
+		struct journal_entry_pin_list *data;
+	}			pin;
+
+	struct journal_space	space[journal_space_nr];
+
+	u64			replay_journal_seq;
+	u64			replay_journal_seq_end;
+
+	struct write_point	wp;
+	spinlock_t		err_lock;
+
+	struct mutex		reclaim_lock;
+	/*
+	 * Used for waiting until journal reclaim has freed up space in the
+	 * journal:
+	 */
+	wait_queue_head_t	reclaim_wait;
+	struct task_struct	*reclaim_thread;
+	bool			reclaim_kicked;
+	unsigned long		next_reclaim;
+	u64			nr_direct_reclaim;
+	u64			nr_background_reclaim;
+
+	unsigned long		last_flushed;
+	struct journal_entry_pin *flush_in_progress;
+	bool			flush_in_progress_dropped;
+	wait_queue_head_t	pin_flush_wait;
+
+	/* protects advancing ja->discard_idx: */
+	struct mutex		discard_lock;
+	bool			can_discard;
+
+	unsigned long		last_flush_write;
+
+	u64			write_start_time;
+
+	u64			nr_flush_writes;
+	u64			nr_noflush_writes;
+	u64			entry_bytes_written;
+
+	u64			low_on_space_start;
+	u64			low_on_pin_start;
+	u64			max_in_flight_start;
+	u64			write_buffer_full_start;
+
+	struct bch2_time_stats	*flush_write_time;
+	struct bch2_time_stats	*noflush_write_time;
+	struct bch2_time_stats	*flush_seq_time;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	res_map;
+#endif
+} __aligned(SMP_CACHE_BYTES);
+
+/*
+ * Embedded in struct bch_dev. First three fields refer to the array of journal
+ * buckets, in bch_sb.
+ */
+struct journal_device {
+	/*
+	 * For each journal bucket, contains the max sequence number of the
+	 * journal writes it contains - so we know when a bucket can be reused.
+	 */
+	u64			*bucket_seq;
+
+	unsigned		sectors_free;
+
+	/*
+	 * discard_idx <= dirty_idx_ondisk <= dirty_idx <= cur_idx:
+	 */
+	unsigned		discard_idx;		/* Next bucket to discard */
+	unsigned		dirty_idx_ondisk;
+	unsigned		dirty_idx;
+	unsigned		cur_idx;		/* Journal bucket we're currently writing to */
+	unsigned		nr;
+
+	u64			*buckets;
+
+	/* Bio for journal reads/writes to this device */
+	struct bio		*bio;
+
+	/* for bch_journal_read_device */
+	struct closure		read;
+};
+
+/*
+ * journal_entry_res - reserve space in every journal entry:
+ */
+struct journal_entry_res {
+	unsigned		u64s;
+};
+
+#endif /* _BCACHEFS_JOURNAL_TYPES_H */