bcachefs: New tracepoint for bch2_trans_get_iter()

Trying to debug an issue where after traverse_all() we shouldn't have to
traverse any iterators... yet we are

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

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 757e5650f33c634b9fd9fd8e6fd78fb70cf15cd7..525afe3509ec06d235c69bed1713eb3f3c686bfc 100644 (file)
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -2020,6 +2020,13 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
                                         unsigned flags)
 {
        struct btree_iter *iter, *best = NULL;
+       struct bpos real_pos, pos_min = POS_MIN;
+
+       if ((flags & BTREE_ITER_TYPE) != BTREE_ITER_NODES &&
+           btree_node_type_is_extents(btree_id) &&
+           !(flags & BTREE_ITER_NOT_EXTENTS) &&
+           !(flags & BTREE_ITER_ALL_SNAPSHOTS))
+               flags |= BTREE_ITER_IS_EXTENTS;
 
        if ((flags & BTREE_ITER_TYPE) != BTREE_ITER_NODES &&
            !btree_type_has_snapshots(btree_id))
@@ -2029,6 +2036,12 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
                pos.snapshot = btree_type_has_snapshots(btree_id)
                        ? U32_MAX : 0;
 
+       real_pos = pos;
+
+       if ((flags & BTREE_ITER_IS_EXTENTS) &&
+           bkey_cmp(pos, POS_MAX))
+               real_pos = bpos_nosnap_successor(pos);
+
        trans_for_each_iter(trans, iter) {
                if (btree_iter_type(iter) != (flags & BTREE_ITER_TYPE))
                        continue;
@@ -2037,8 +2050,8 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
                        continue;
 
                if (best) {
-                       int cmp = bkey_cmp(bpos_diff(best->real_pos, pos),
-                                          bpos_diff(iter->real_pos, pos));
+                       int cmp = bkey_cmp(bpos_diff(best->real_pos, real_pos),
+                                          bpos_diff(iter->real_pos, real_pos));
 
                        if (cmp < 0 ||
                            ((cmp == 0 && btree_iter_keep(trans, iter))))
@@ -2048,6 +2061,13 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
                best = iter;
        }
 
+       trace_trans_get_iter(_RET_IP_, trans->ip,
+                            btree_id,
+                            &real_pos, locks_want,
+                            best ? &best->real_pos : &pos_min,
+                            best ? best->locks_want : 0,
+                            best ? best->uptodate : BTREE_ITER_NEED_TRAVERSE);
+
        if (!best) {
                iter = btree_trans_iter_alloc(trans);
                bch2_btree_iter_init(trans, iter, btree_id);
@@ -2061,12 +2081,6 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
        trans->iters_live       |= 1ULL << iter->idx;
        trans->iters_touched    |= 1ULL << iter->idx;
 
-       if ((flags & BTREE_ITER_TYPE) != BTREE_ITER_NODES &&
-           btree_node_type_is_extents(btree_id) &&
-           !(flags & BTREE_ITER_NOT_EXTENTS) &&
-           !(flags & BTREE_ITER_ALL_SNAPSHOTS))
-               flags |= BTREE_ITER_IS_EXTENTS;
-
        iter->flags = flags;
 
        iter->snapshot = pos.snapshot;
@@ -2098,7 +2112,7 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
        iter->min_depth = depth;
 
        bch2_btree_iter_set_pos(iter, pos);
-       btree_iter_set_search_pos(iter, btree_iter_search_key(iter));
+       btree_iter_set_search_pos(iter, real_pos);
 
        return iter;
 }

diff --git a/fs/bcachefs/trace.h b/fs/bcachefs/trace.h
index c6d98f4c50e7707929f842aa4947ce05cdb7dcf8..7e518f7618d40a0acfb4dbd4a5929874560c4cae 100644 (file)
--- a/fs/bcachefs/trace.h
+++ b/fs/bcachefs/trace.h
@@ -528,6 +528,62 @@ TRACE_EVENT(copygc,
                __entry->buckets_moved, __entry->buckets_not_moved)
 );
 
+TRACE_EVENT(trans_get_iter,
+       TP_PROTO(unsigned long caller, unsigned long ip,
+                enum btree_id btree_id,
+                struct bpos *pos_want,
+                unsigned locks_want,
+                struct bpos *pos_found,
+                unsigned locks_found,
+                unsigned uptodate),
+       TP_ARGS(caller, ip, btree_id,
+               pos_want, locks_want,
+               pos_found, locks_found,
+               uptodate),
+
+       TP_STRUCT__entry(
+               __field(unsigned long,  caller                  )
+               __field(unsigned long,  ip                      )
+               __field(u8,             btree_id                )
+               __field(u8,             uptodate                )
+               __field(u8,             locks_want              )
+               __field(u8,             locks_found             )
+               __field(u64,            pos_want_inode          )
+               __field(u64,            pos_want_offset         )
+               __field(u32,            pos_want_snapshot       )
+               __field(u64,            pos_found_inode         )
+               __field(u64,            pos_found_offset        )
+               __field(u32,            pos_found_snapshot      )
+       ),
+
+       TP_fast_assign(
+               __entry->caller                 = caller;
+               __entry->ip                     = ip;
+               __entry->btree_id               = btree_id;
+               __entry->uptodate               = uptodate;
+               __entry->pos_want_inode         = pos_want->inode;
+               __entry->pos_want_offset        = pos_want->offset;
+               __entry->pos_want_snapshot      = pos_want->snapshot;
+               __entry->pos_found_inode        = pos_found->inode;
+               __entry->pos_found_offset       = pos_found->offset;
+               __entry->pos_found_snapshot     = pos_found->snapshot;
+       ),
+
+       TP_printk("%ps %pS btree %u uptodate %u want %llu:%llu:%u locks %u found %llu:%llu:%u locks %u",
+                 (void *) __entry->caller,
+                 (void *) __entry->ip,
+                 __entry->btree_id,
+                 __entry->uptodate,
+                 __entry->pos_want_inode,
+                 __entry->pos_want_offset,
+                 __entry->pos_want_snapshot,
+                 __entry->locks_want,
+                 __entry->pos_found_inode,
+                 __entry->pos_found_offset,
+                 __entry->pos_found_snapshot,
+                 __entry->locks_found)
+);
+
 TRACE_EVENT(transaction_restart_ip,
        TP_PROTO(unsigned long caller, unsigned long ip),
        TP_ARGS(caller, ip),