bcachefs: Fix bch2_journal_pin_set()

When bch2_journal_pin_set() is updating an existing pin, we shouldn't
call bch2_journal_reclaim_fast() after dropping the old pin and before
dropping the new pin - that could reclaim the entry we're trying to pin.

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

diff --git a/fs/bcachefs/journal_reclaim.c b/fs/bcachefs/journal_reclaim.c
index b30730ce58c530dead4446d23e73446630000145..f55fc0b11977fff12399cc1a754c376b19c4764e 100644 (file)
--- a/fs/bcachefs/journal_reclaim.c
+++ b/fs/bcachefs/journal_reclaim.c
@@ -346,13 +346,13 @@ void bch2_journal_pin_put(struct journal *j, u64 seq)
        }
 }
 
-static inline void __journal_pin_drop(struct journal *j,
+static inline bool __journal_pin_drop(struct journal *j,
                                      struct journal_entry_pin *pin)
 {
        struct journal_entry_pin_list *pin_list;
 
        if (!journal_pin_active(pin))
-               return;
+               return false;
 
        if (j->flush_in_progress == pin)
                j->flush_in_progress_dropped = true;
@@ -365,16 +365,16 @@ static inline void __journal_pin_drop(struct journal *j,
         * Unpinning a journal entry make make journal_next_bucket() succeed, if
         * writing a new last_seq will now make another bucket available:
         */
-       if (atomic_dec_and_test(&pin_list->count) &&
-           pin_list == &fifo_peek_front(&j->pin))
-               bch2_journal_reclaim_fast(j);
+       return atomic_dec_and_test(&pin_list->count) &&
+               pin_list == &fifo_peek_front(&j->pin);
 }
 
 void bch2_journal_pin_drop(struct journal *j,
                           struct journal_entry_pin *pin)
 {
        spin_lock(&j->lock);
-       __journal_pin_drop(j, pin);
+       if (__journal_pin_drop(j, pin))
+               bch2_journal_reclaim_fast(j);
        spin_unlock(&j->lock);
 }
 
@@ -383,6 +383,7 @@ void bch2_journal_pin_set(struct journal *j, u64 seq,
                          journal_pin_flush_fn flush_fn)
 {
        struct journal_entry_pin_list *pin_list;
+       bool reclaim;
 
        spin_lock(&j->lock);
 
@@ -399,7 +400,7 @@ void bch2_journal_pin_set(struct journal *j, u64 seq,
 
        pin_list = journal_seq_pin(j, seq);
 
-       __journal_pin_drop(j, pin);
+       reclaim = __journal_pin_drop(j, pin);
 
        atomic_inc(&pin_list->count);
        pin->seq        = seq;
@@ -411,6 +412,9 @@ void bch2_journal_pin_set(struct journal *j, u64 seq,
                list_add(&pin->list, &pin_list->list);
        else
                list_add(&pin->list, &pin_list->flushed);
+
+       if (reclaim)
+               bch2_journal_reclaim_fast(j);
        spin_unlock(&j->lock);
 
        /*