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| author | Kent Overstreet <kent.overstreet@gmail.com> | 2021-01-21 15:28:59 -0500 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-10-22 17:08:52 -0400 |
| commit | 2abe542087d9cb1bc7bb8ac7ae262afccbdb7aa6 (patch) | |
| tree | c33f5733a5cf3f091e59e5084be29ef5819a9f71 /fs/bcachefs/bcachefs_format.h | |
| parent | 7f4e1d5d0faff0d72e9f6708bf98488d76533846 (diff) | |
| download | lwn-2abe542087d9cb1bc7bb8ac7ae262afccbdb7aa6.tar.gz lwn-2abe542087d9cb1bc7bb8ac7ae262afccbdb7aa6.zip | |
bcachefs: Persist 64 bit io clocks
Originally, bcachefs - going back to bcache - stored, for each bucket, a
16 bit counter corresponding to how long it had been since the bucket
was read from. But, this required periodically rescaling counters on
every bucket to avoid wraparound. That wasn't an issue in bcache, where
we'd perodically rewrite the per bucket metadata all at once, but in
bcachefs we're trying to avoid having to walk every single bucket.
This patch switches to persisting 64 bit io clocks, corresponding to the
64 bit bucket timestaps introduced in the previous patch with
KEY_TYPE_alloc_v2.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'fs/bcachefs/bcachefs_format.h')
| -rw-r--r-- | fs/bcachefs/bcachefs_format.h | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h index b6c7e57b6bcd..5dab5bfd228a 100644 --- a/fs/bcachefs/bcachefs_format.h +++ b/fs/bcachefs/bcachefs_format.h @@ -1143,8 +1143,8 @@ struct bch_sb_field_clean { struct bch_sb_field field; __le32 flags; - __le16 read_clock; - __le16 write_clock; + __le16 _read_clock; /* no longer used */ + __le16 _write_clock; __le64 journal_seq; union { @@ -1511,7 +1511,8 @@ static inline __u64 __bset_magic(struct bch_sb *sb) x(blacklist, 3) \ x(blacklist_v2, 4) \ x(usage, 5) \ - x(data_usage, 6) + x(data_usage, 6) \ + x(clock, 7) enum { #define x(f, nr) BCH_JSET_ENTRY_##f = nr, @@ -1559,6 +1560,13 @@ struct jset_entry_data_usage { struct bch_replicas_entry r; } __attribute__((packed)); +struct jset_entry_clock { + struct jset_entry entry; + __u8 rw; + __u8 pad[7]; + __le64 time; +} __attribute__((packed)); + /* * On disk format for a journal entry: * seq is monotonically increasing; every journal entry has its own unique @@ -1581,8 +1589,8 @@ struct jset { __u8 encrypted_start[0]; - __le16 read_clock; - __le16 write_clock; + __le16 _read_clock; /* no longer used */ + __le16 _write_clock; /* Sequence number of oldest dirty journal entry */ __le64 last_seq; |