Merge tag 'bcachefs-2024-06-28' of https://evilpiepirate.org/git/bcachefs

Pull bcachefs fixes from Kent Overstreet:
 "Simple stuff:

   - NULL ptr/err ptr deref fixes

   - fix for getting wedged on shutdown after journal error

   - fix missing recalc_capacity() call, capacity now changes correctly
     after a device goes read only

     however: our capacity calculation still doesn't take into account
     when we have mixed ro/rw devices and the ro devices have data on
     them, that's going to be a more involved fix to separate accounting
     for "capacity used on ro devices" and "capacity used on rw devices"

   - boring syzbot stuff

  Slightly more involved:

   - discard, invalidate workers are now per device

     this has the effect of simplifying how we take device refs in these
     paths, and the device ref cleanup fixes a longstanding race between
     the device removal path and the discard path

   - fixes for how the debugfs code takes refs on btree_trans objects we
     have debugfs code that prints in use btree_trans objects.

     It uses closure_get() on trans->ref, which is mainly for the cycle
     detector, but the debugfs code was using it on a closure that may
     have hit 0, which is not allowed; for performance reasons we cannot
     avoid having not-in-use transactions on the global list.

     Introduce some new primitives to fix this and make the
     synchronization here a whole lot saner"

* tag 'bcachefs-2024-06-28' of https://evilpiepirate.org/git/bcachefs:
  bcachefs: Fix kmalloc bug in __snapshot_t_mut
  bcachefs: Discard, invalidate workers are now per device
  bcachefs: Fix shift-out-of-bounds in bch2_blacklist_entries_gc
  bcachefs: slab-use-after-free Read in bch2_sb_errors_from_cpu
  bcachefs: Add missing bch2_journal_do_writes() call
  bcachefs: Fix null ptr deref in journal_pins_to_text()
  bcachefs: Add missing recalc_capacity() call
  bcachefs: Fix btree_trans list ordering
  bcachefs: Fix race between trans_put() and btree_transactions_read()
  closures: closure_get_not_zero(), closure_return_sync()
  bcachefs: Make btree_deadlock_to_text() clearer
  bcachefs: fix seqmutex_relock()
  bcachefs: Fix freeing of error pointers

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/closure.h b/include/linux/closure.h
index 99155df162d0..59b8c06b11ff 100644
--- a/include/linux/closure.h
+++ b/include/linux/closure.h
@@ -285,6 +285,21 @@ static inline void closure_get(struct closure *cl)
 }
 
 /**
+ * closure_get_not_zero
+ */
+static inline bool closure_get_not_zero(struct closure *cl)
+{
+	unsigned old = atomic_read(&cl->remaining);
+	do {
+		if (!(old & CLOSURE_REMAINING_MASK))
+			return false;
+
+	} while (!atomic_try_cmpxchg_acquire(&cl->remaining, &old, old + 1));
+
+	return true;
+}
+
+/**
  * closure_init - Initialize a closure, setting the refcount to 1
  * @cl:		closure to initialize
  * @parent:	parent of the new closure. cl will take a refcount on it for its
@@ -310,6 +325,12 @@ static inline void closure_init_stack(struct closure *cl)
 	atomic_set(&cl->remaining, CLOSURE_REMAINING_INITIALIZER);
 }
 
+static inline void closure_init_stack_release(struct closure *cl)
+{
+	memset(cl, 0, sizeof(struct closure));
+	atomic_set_release(&cl->remaining, CLOSURE_REMAINING_INITIALIZER);
+}
+
 /**
  * closure_wake_up - wake up all closures on a wait list,
  *		     with memory barrier
@@ -355,6 +376,8 @@ do {									\
  */
 #define closure_return(_cl)	continue_at((_cl), NULL, NULL)
 
+void closure_return_sync(struct closure *cl);
+
 /**
  * continue_at_nobarrier - jump to another function without barrier
  *