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>

1 files changed, 1 insertions, 8 deletions

diff --git a/fs/bcachefs/buckets.h b/fs/bcachefs/buckets.h
index 4103ea7e769a..50989d286190 100644
--- a/fs/bcachefs/buckets.h
+++ b/fs/bcachefs/buckets.h
@@ -58,20 +58,13 @@ static inline struct bucket *bucket(struct bch_dev *ca, size_t b)
 	return __bucket(ca, b, false);
 }
 
-static inline u16 bucket_last_io(struct bch_fs *c, struct bucket *g, int rw)
-{
-	return c->bucket_clock[rw].hand - g->io_time[rw];
-}
-
 /*
  * bucket_gc_gen() returns the difference between the bucket's current gen and
  * the oldest gen of any pointer into that bucket in the btree.
  */
 
-static inline u8 bucket_gc_gen(struct bch_dev *ca, size_t b)
+static inline u8 bucket_gc_gen(struct bucket *g)
 {
-	struct bucket *g = bucket(ca, b);
-
 	return g->mark.gen - g->oldest_gen;
 }