bcachefs: jset_entry_datetime

This gives us a way to record the date and time every journal entry was
written - useful for debugging.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs_format.h

@@ -1275,7 +1275,8 @@ static inline __u64 __bset_magic(struct bch_sb *sb)
 	x(dev_usage,		8)		\
 	x(log,			9)		\
 	x(overwrite,		10)		\
-	x(write_buffer_keys,	11)
+	x(write_buffer_keys,	11)		\
+	x(datetime,		12)
 
 enum {
 #define x(f, nr)	BCH_JSET_ENTRY_##f	= nr,
@@ -1376,6 +1377,11 @@ struct jset_entry_log {
 	u8			d[];
 } __packed __aligned(8);
 
+struct jset_entry_datetime {
+	struct jset_entry	entry;
+	__le64			seconds;
+} __packed __aligned(8);
+
 /*
  * On disk format for a journal entry:
  * seq is monotonically increasing; every journal entry has its own unique

fs/bcachefs/journal_io.c

@@ -39,6 +39,14 @@ static void bch2_journal_replay_to_text(struct printbuf *out, struct bch_fs *c,
 	prt_printf(out, "seq %llu ", le64_to_cpu(j->j.seq));
 
 	bch2_journal_ptrs_to_text(out, c, j);
+
+	struct jset_entry *entry;
+	for_each_jset_entry_type(entry, &j->j, BCH_JSET_ENTRY_datetime) {
+		struct jset_entry_datetime *datetime =
+			container_of(entry, struct jset_entry_datetime, entry);
+		bch2_prt_datetime(out, le64_to_cpu(datetime->seconds));
+		break;
+	}
 }
 
 static struct nonce journal_nonce(const struct jset *jset)
@@ -754,6 +762,37 @@ static void journal_entry_write_buffer_keys_to_text(struct printbuf *out, struct
 	journal_entry_btree_keys_to_text(out, c, entry);
 }
 
+static int journal_entry_datetime_validate(struct bch_fs *c,
+				struct jset *jset,
+				struct jset_entry *entry,
+				unsigned version, int big_endian,
+				enum bkey_invalid_flags flags)
+{
+	unsigned bytes = vstruct_bytes(entry);
+	unsigned expected = 16;
+	int ret = 0;
+
+	if (journal_entry_err_on(vstruct_bytes(entry) < expected,
+				 c, version, jset, entry,
+				 journal_entry_dev_usage_bad_size,
+				 "bad size (%u < %u)",
+				 bytes, expected)) {
+		journal_entry_null_range(entry, vstruct_next(entry));
+		return ret;
+	}
+fsck_err:
+	return ret;
+}
+
+static void journal_entry_datetime_to_text(struct printbuf *out, struct bch_fs *c,
+					    struct jset_entry *entry)
+{
+	struct jset_entry_datetime *datetime =
+		container_of(entry, struct jset_entry_datetime, entry);
+
+	bch2_prt_datetime(out, le64_to_cpu(datetime->seconds));
+}
+
 struct jset_entry_ops {
 	int (*validate)(struct bch_fs *, struct jset *,
 			struct jset_entry *, unsigned, int,
@@ -1794,6 +1833,11 @@ static int bch2_journal_write_prep(struct journal *j, struct journal_buf *w)
 
 	end	= bch2_btree_roots_to_journal_entries(c, end, btree_roots_have);
 
+	struct jset_entry_datetime *d =
+		container_of(jset_entry_init(&end, sizeof(*d)), struct jset_entry_datetime, entry);
+	d->entry.type	= BCH_JSET_ENTRY_datetime;
+	d->seconds	= cpu_to_le64(ktime_get_real_seconds());
+
 	bch2_journal_super_entries_add_common(c, &end, seq);
 	u64s	= (u64 *) end - (u64 *) start;
 	BUG_ON(u64s > j->entry_u64s_reserved);

fs/bcachefs/journal_io.h

@@ -65,4 +65,20 @@ int bch2_journal_read(struct bch_fs *, u64 *, u64 *, u64 *);
 
 CLOSURE_CALLBACK(bch2_journal_write);
 
+static inline struct jset_entry *jset_entry_init(struct jset_entry **end, size_t size)
+{
+	struct jset_entry *entry = *end;
+	unsigned u64s = DIV_ROUND_UP(size, sizeof(u64));
+
+	memset(entry, 0, u64s * sizeof(u64));
+	/*
+	 * The u64s field counts from the start of data, ignoring the shared
+	 * fields.
+	 */
+	entry->u64s = cpu_to_le16(u64s - 1);
+
+	*end = vstruct_next(*end);
+	return entry;
+}
+
 #endif /* _BCACHEFS_JOURNAL_IO_H */

fs/bcachefs/sb-clean.c

@@ -171,22 +171,6 @@ struct bch_sb_field_clean *bch2_read_superblock_clean(struct bch_fs *c)
 	return ERR_PTR(ret);
 }
 
-static struct jset_entry *jset_entry_init(struct jset_entry **end, size_t size)
-{
-	struct jset_entry *entry = *end;
-	unsigned u64s = DIV_ROUND_UP(size, sizeof(u64));
-
-	memset(entry, 0, u64s * sizeof(u64));
-	/*
-	 * The u64s field counts from the start of data, ignoring the shared
-	 * fields.
-	 */
-	entry->u64s = cpu_to_le16(u64s - 1);
-
-	*end = vstruct_next(*end);
-	return entry;
-}
-
 void bch2_journal_super_entries_add_common(struct bch_fs *c,
 					   struct jset_entry **end,
 					   u64 journal_seq)