Add new fields for split brain detection: - bch_member->seq, which tracks the sequence number of the last superblock write that happened to each member device
- bch_sb->write_time, which tracks the time of the last superblock write, to allow detection of when two members have diverged but had the same number of superblock writes. Signed-off-by: Kent Overstreet <[email protected]> --- fs/bcachefs/bcachefs_format.h | 4 +++- fs/bcachefs/sb-members.c | 5 +++++ fs/bcachefs/super-io.c | 10 ++++++++++ 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h index 5b44598b9df9..b22868ca9770 100644 --- a/fs/bcachefs/bcachefs_format.h +++ b/fs/bcachefs/bcachefs_format.h @@ -1294,6 +1294,7 @@ struct bch_member { __le64 errors[BCH_MEMBER_ERROR_NR]; __le64 errors_at_reset[BCH_MEMBER_ERROR_NR]; __le64 errors_reset_time; + __le64 seq; }; #define BCH_MEMBER_V1_BYTES 56 @@ -1761,7 +1762,8 @@ struct bch_sb { __le32 time_base_hi; __le32 time_precision; - __le64 flags[8]; + __le64 flags[7]; + __le64 write_time; __le64 features[2]; __le64 compat[2]; diff --git a/fs/bcachefs/sb-members.c b/fs/bcachefs/sb-members.c index 6a7e20de971c..4c6908cfca05 100644 --- a/fs/bcachefs/sb-members.c +++ b/fs/bcachefs/sb-members.c @@ -235,6 +235,11 @@ static void member_to_text(struct printbuf *out, prt_printf(out, "(never)"); prt_newline(out); + prt_printf(out, "Last superblock write:"); + prt_tab(out); + prt_u64(out, le64_to_cpu(m.seq)); + prt_newline(out); + prt_printf(out, "State:"); prt_tab(out); prt_printf(out, "%s", diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c index a93e53d0b37e..3ebe14c806ac 100644 --- a/fs/bcachefs/super-io.c +++ b/fs/bcachefs/super-io.c @@ -890,6 +890,11 @@ int bch2_write_super(struct bch_fs *c) le64_add_cpu(&c->disk_sb.sb->seq, 1); + struct bch_sb_field_members_v2 *mi = bch2_sb_field_get(c->disk_sb.sb, members_v2); + for_each_online_member(ca, c, i) + __bch2_members_v2_get_mut(mi, i)->seq = c->disk_sb.sb->seq; + c->disk_sb.sb->write_time = cpu_to_le64(ktime_get_real_seconds()); + if (test_bit(BCH_FS_ERROR, &c->flags)) SET_BCH_SB_HAS_ERRORS(c->disk_sb.sb, 1); if (test_bit(BCH_FS_TOPOLOGY_ERROR, &c->flags)) @@ -1193,6 +1198,11 @@ void bch2_sb_to_text(struct printbuf *out, struct bch_sb *sb, prt_printf(out, "%llu", le64_to_cpu(sb->seq)); prt_newline(out); + prt_printf(out, "Time of last write:"); + prt_tab(out); + bch2_prt_date_seconds(out, le64_to_cpu(sb->write_time)); + prt_newline(out); + prt_printf(out, "Superblock size:"); prt_tab(out); prt_printf(out, "%zu", vstruct_bytes(sb)); -- 2.42.0
