bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 242 insertions, 0 deletions

diff --git a/fs/bcachefs/journal_types.h b/fs/bcachefs/journal_types.h
new file mode 100644
index 000000000000..cf291227cffb
--- /dev/null
+++ b/fs/bcachefs/journal_types.h
@@ -0,0 +1,242 @@
+/* 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"
+
+struct journal_res;
+
+/*
+ * We put two 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);
+
+	struct closure_waitlist	wait;
+
+	unsigned		size;
+	unsigned		disk_sectors;
+	/* bloom filter: */
+	unsigned long		has_inode[1024 / sizeof(unsigned long)];
+};
+
+/*
+ * Something that makes a journal entry dirty - i.e. a btree node that has to be
+ * flushed:
+ */
+
+struct journal_entry_pin_list {
+	struct list_head		list;
+	struct list_head		flushed;
+	atomic_t			count;
+	struct bch_devs_list		devs;
+};
+
+struct journal;
+struct journal_entry_pin;
+typedef void (*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;
+	struct journal_entry_pin_list	*pin_list;
+};
+
+/* corresponds to a btree node with a blacklisted bset: */
+struct blacklisted_node {
+	__le64			seq;
+	enum btree_id		btree_id;
+	struct bpos		pos;
+};
+
+struct journal_seq_blacklist {
+	struct list_head	list;
+	u64			start;
+	u64			end;
+
+	struct journal_entry_pin pin;
+
+	struct blacklisted_node	*entries;
+	size_t			nr_entries;
+};
+
+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:1,
+				prev_buf_unwritten:1,
+				buf0_count:21,
+				buf1_count:21;
+	};
+};
+
+/* 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)
+
+/*
+ * JOURNAL_NEED_WRITE - current (pending) journal entry should be written ASAP,
+ * either because something's waiting on the write to complete or because it's
+ * been dirty too long and the timer's expired.
+ */
+
+enum {
+	JOURNAL_REPLAY_DONE,
+	JOURNAL_STARTED,
+	JOURNAL_NEED_WRITE,
+	JOURNAL_NOT_EMPTY,
+};
+
+/* Embedded in struct bch_fs */
+struct journal {
+	/* Fastpath stuff up front: */
+
+	unsigned long		flags;
+
+	union journal_res_state reservations;
+	unsigned		cur_entry_u64s;
+	unsigned		prev_buf_sectors;
+	unsigned		cur_buf_sectors;
+	unsigned		buf_size_want;
+
+	/*
+	 * Two journal entries -- one is currently open for new entries, the
+	 * other is possibly being written out.
+	 */
+	struct journal_buf	buf[2];
+
+	spinlock_t		lock;
+
+	/* 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;
+
+	/* last_seq from the most recent journal entry written */
+	u64			last_seq_ondisk;
+
+	/*
+	 * 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;
+	u64			replay_journal_seq;
+
+	struct mutex		blacklist_lock;
+	struct list_head	seq_blacklist;
+	struct journal_seq_blacklist *new_blacklist;
+
+	BKEY_PADDED(key);
+	struct write_point	wp;
+	spinlock_t		err_lock;
+
+	struct delayed_work	reclaim_work;
+	unsigned long		last_flushed;
+
+	/* protects advancing ja->last_idx: */
+	struct mutex		reclaim_lock;
+	unsigned		write_delay_ms;
+	unsigned		reclaim_delay_ms;
+
+	u64			res_get_blocked_start;
+	u64			need_write_time;
+	u64			write_start_time;
+
+	struct bch2_time_stats	*write_time;
+	struct bch2_time_stats	*delay_time;
+	struct bch2_time_stats	*blocked_time;
+	struct bch2_time_stats	*flush_seq_time;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	res_map;
+#endif
+};
+
+/*
+ * 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;
+
+	/* Journal bucket we're currently writing to */
+	unsigned		cur_idx;
+
+	/* Last journal bucket that still contains an open journal entry */
+
+	/*
+	 * j->lock and j->reclaim_lock must both be held to modify, j->lock
+	 * sufficient to read:
+	 */
+	unsigned		last_idx;
+	unsigned		nr;
+	u64			*buckets;
+
+	/* Bio for journal reads/writes to this device */
+	struct bio		*bio;
+
+	/* for bch_journal_read_device */
+	struct closure		read;
+};
+
+#endif /* _BCACHEFS_JOURNAL_TYPES_H */