From 01db5e5f2f6e01cbea01872850223e58075baf63 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Thu, 21 Dec 2023 21:05:07 -0500 Subject: [PATCH] bcachefs: Fix insufficient disk reservation with compression + snapshots When overwriting and splitting existing extents, we weren't correctly accounting for a 3 way split of a compressed extent. Signed-off-by: Kent Overstreet --- fs/bcachefs/btree_update.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/bcachefs/btree_update.c b/fs/bcachefs/btree_update.c index 25fdca00bf7b..2fd3c8cc6f51 100644 --- a/fs/bcachefs/btree_update.c +++ b/fs/bcachefs/btree_update.c @@ -186,8 +186,11 @@ int bch2_trans_update_extent_overwrite(struct btree_trans *trans, enum btree_id btree_id = iter->btree_id; struct bkey_i *update; struct bpos new_start = bkey_start_pos(new.k); - bool front_split = bkey_lt(bkey_start_pos(old.k), new_start); - bool back_split = bkey_gt(old.k->p, new.k->p); + unsigned front_split = bkey_lt(bkey_start_pos(old.k), new_start); + unsigned back_split = bkey_gt(old.k->p, new.k->p); + unsigned middle_split = (front_split || back_split) && + old.k->p.snapshot != new.k->p.snapshot; + unsigned nr_splits = front_split + back_split + middle_split; int ret = 0, compressed_sectors; /* @@ -195,10 +198,9 @@ int bch2_trans_update_extent_overwrite(struct btree_trans *trans, * so that __bch2_trans_commit() can increase our disk * reservation: */ - if (((front_split && back_split) || - ((front_split || back_split) && old.k->p.snapshot != new.k->p.snapshot)) && + if (nr_splits > 1 && (compressed_sectors = bch2_bkey_sectors_compressed(old))) - trans->extra_journal_res += compressed_sectors; + trans->extra_journal_res += compressed_sectors * (nr_splits - 1); if (front_split) { update = bch2_bkey_make_mut_noupdate(trans, old); @@ -216,8 +218,7 @@ int bch2_trans_update_extent_overwrite(struct btree_trans *trans, } /* If we're overwriting in a different snapshot - middle split: */ - if (old.k->p.snapshot != new.k->p.snapshot && - (front_split || back_split)) { + if (middle_split) { update = bch2_bkey_make_mut_noupdate(trans, old); if ((ret = PTR_ERR_OR_ZERO(update))) return ret;