From 7b6759b1991d427cf9a562b2891b8c3e87a19c76 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Tue, 13 May 2025 12:55:44 -0400 Subject: [PATCH] bcachefs: Fix livelock in journal_entry_open() When the journal is low on space, we might do discards from journal_res_get() -> journal_entry_open(). Make sure we set j->can_discard correctly, so that if we're low on space but not because discards aren't keeping up we don't livelock. Fixes: 8e4d28036c29 ("bcachefs: Don't aggressively discard the journal") Signed-off-by: Kent Overstreet --- fs/bcachefs/journal_reclaim.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/fs/bcachefs/journal_reclaim.c b/fs/bcachefs/journal_reclaim.c index 976464d8a695..cc00b0fc40d8 100644 --- a/fs/bcachefs/journal_reclaim.c +++ b/fs/bcachefs/journal_reclaim.c @@ -17,6 +17,8 @@ #include #include +static bool __should_discard_bucket(struct journal *, struct journal_device *); + /* Free space calculations: */ static unsigned journal_space_from(struct journal_device *ja, @@ -203,8 +205,7 @@ void bch2_journal_space_available(struct journal *j) ja->bucket_seq[ja->dirty_idx_ondisk] < j->last_seq_ondisk) ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + 1) % ja->nr; - if (ja->discard_idx != ja->dirty_idx_ondisk) - can_discard = true; + can_discard |= __should_discard_bucket(j, ja); max_entry_size = min_t(unsigned, max_entry_size, ca->mi.bucket_size); nr_online++; @@ -264,13 +265,19 @@ out: /* Discards - last part of journal reclaim: */ -static bool should_discard_bucket(struct journal *j, struct journal_device *ja) +static bool __should_discard_bucket(struct journal *j, struct journal_device *ja) { - spin_lock(&j->lock); unsigned min_free = max(4, ja->nr / 8); - bool ret = bch2_journal_dev_buckets_available(j, ja, journal_space_discarded) < min_free && + return bch2_journal_dev_buckets_available(j, ja, journal_space_discarded) < + min_free && ja->discard_idx != ja->dirty_idx_ondisk; +} + +static bool should_discard_bucket(struct journal *j, struct journal_device *ja) +{ + spin_lock(&j->lock); + bool ret = __should_discard_bucket(j, ja); spin_unlock(&j->lock); return ret; -- 2.25.1