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bcachefs: Fix a trans path overflow in bch2_btree_delete_range_trans()

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bch2_btree_delete_range_trans() was using btree_trans_too_many_iters()
to avoid path overflow, but this was buggy here (and also
btree_trans_too_many_iters() is suspect in general).

btree_trans_too_many_iters() only returns true when we're close to the
maximum number of paths - within 8 - but extent insert/delete assumes
that it can use more paths than that.

Instead, we need to call bch2_trans_begin() on every loop iteration.
Since we don't want to call bch2_trans_begin() (restarting the outer
transaction) if the call was a no-op - if we had no work to do - we have
to structure things a bit oddly.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2022-09-28 10:16:57 -04:00
parent ae10fe017b
commit 685e0f0c47
1 changed files with 20 additions and 13 deletions
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33
fs/bcachefs/btree_update_leaf.c
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@ -1651,15 +1651,18 @@ int bch2_btree_delete_range_trans(struct btree_trans *trans, enum btree_id id,
int ret = 0;
bch2_trans_iter_init(trans, &iter, id, start, BTREE_ITER_INTENT);
retry:
while ((k = bch2_btree_iter_peek(&iter)).k &&
!(ret = bkey_err(k) ?:
btree_trans_too_many_iters(trans)) &&
bkey_cmp(iter.pos, end) < 0) {
while ((k = bch2_btree_iter_peek(&iter)).k) {
struct disk_reservation disk_res =
bch2_disk_reservation_init(trans->c, 0);
struct bkey_i delete;
ret = bkey_err(k);
if (ret)
goto err;
if (bkey_cmp(iter.pos, end) >= 0)
break;
bkey_init(&delete.k);
/*
@ -1688,23 +1691,27 @@ retry:
ret = bch2_extent_trim_atomic(trans, &iter, &delete);
if (ret)
break;
goto err;
}
ret = bch2_trans_update(trans, &iter, &delete, update_flags) ?:
bch2_trans_commit(trans, &disk_res, journal_seq,
BTREE_INSERT_NOFAIL);
bch2_disk_reservation_put(trans->c, &disk_res);
err:
/*
* the bch2_trans_begin() call is in a weird place because we
* need to call it after every transaction commit, to avoid path
* overflow, but don't want to call it if the delete operation
* is a no-op and we have no work to do:
*/
bch2_trans_begin(trans);
if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
ret = 0;
if (ret)
break;
}
if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
bch2_trans_begin(trans);
ret = 0;
goto retry;
}
bch2_trans_iter_exit(trans, &iter);
if (!ret && trans_was_restarted(trans, restart_count))