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bcachefs: Improve key_visible_in_snapshot()

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Delete a redundant bch2_snapshot_is_ancestor() check, and convert some
assertions to debug assertions.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-07-16 18:15:01 -04:00
parent a397b8df5e
commit 464ee1929b
1 changed files with 16 additions and 8 deletions
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24
fs/bcachefs/fsck.c
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@ -517,15 +517,14 @@ static bool key_visible_in_snapshot(struct bch_fs *c, struct snapshots_seen *see
u32 id, u32 ancestor)
{
ssize_t i;
u32 top = seen->ids.nr ? seen->ids.data[seen->ids.nr - 1].equiv : 0;
BUG_ON(id > ancestor);
BUG_ON(!bch2_snapshot_is_equiv(c, id));
BUG_ON(!bch2_snapshot_is_equiv(c, ancestor));
EBUG_ON(id > ancestor);
EBUG_ON(!bch2_snapshot_is_equiv(c, id));
EBUG_ON(!bch2_snapshot_is_equiv(c, ancestor));
/* @ancestor should be the snapshot most recently added to @seen */
BUG_ON(ancestor != seen->pos.snapshot);
BUG_ON(ancestor != top);
EBUG_ON(ancestor != seen->pos.snapshot);
EBUG_ON(ancestor != seen->ids.data[seen->ids.nr - 1].equiv);
if (id == ancestor)
return true;
@ -533,11 +532,20 @@ static bool key_visible_in_snapshot(struct bch_fs *c, struct snapshots_seen *see
if (!bch2_snapshot_is_ancestor(c, id, ancestor))
return false;
/*
* We know that @id is a descendant of @ancestor, we're checking if
* we've seen a key that overwrote @ancestor - i.e. also a descendent of
* @ascestor and with @id as a descendent.
*
* But we already know that we're scanning IDs between @id and @ancestor
* numerically, since snapshot ID lists are kept sorted, so if we find
* an id that's an ancestor of @id we're done:
*/
for (i = seen->ids.nr - 2;
i >= 0 && seen->ids.data[i].equiv >= id;
--i)
if (bch2_snapshot_is_ancestor(c, id, seen->ids.data[i].equiv) &&
bch2_snapshot_is_ancestor(c, seen->ids.data[i].equiv, ancestor))
if (bch2_snapshot_is_ancestor(c, id, seen->ids.data[i].equiv))
return false;
return true;