bcachefs: Create allocator threads when allocating filesystem

We're seeing failures to mount because of a failure to start the
allocator threads, which currently happens fairly late in the mount
process, after walking all metadata, and kthread_create() fails if
something has tried to kill the mount process, which is probably not
what we want.

This patch avoids this issue by creating, but not starting, the
allocator threads when we preallocate all of our other in memory data
structures.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

2 files changed, 25 insertions, 1 deletions

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index aa0917201c6b..8e9cbc0625f7 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -1068,6 +1068,12 @@ static int discard_invalidated_buckets(struct bch_fs *c, struct bch_dev *ca)
 	return 0;
 }
 
+static inline bool allocator_thread_running(struct bch_dev *ca)
+{
+	return ca->mi.state == BCH_MEMBER_STATE_RW &&
+		test_bit(BCH_FS_ALLOCATOR_RUNNING, &ca->fs->flags);
+}
+
 /**
  * bch_allocator_thread - move buckets from free_inc to reserves
  *
@@ -1084,9 +1090,16 @@ static int bch2_allocator_thread(void *arg)
 	int ret;
 
 	set_freezable();
-	ca->allocator_state = ALLOCATOR_RUNNING;
 
 	while (1) {
+		if (!allocator_thread_running(ca)) {
+			ca->allocator_state = ALLOCATOR_STOPPED;
+			if (kthread_wait_freezable(allocator_thread_running(ca)))
+				break;
+		}
+
+		ca->allocator_state = ALLOCATOR_RUNNING;
+
 		cond_resched();
 		if (kthread_should_stop())
 			break;
diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index 8e6b4413d820..e43f7790094a 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -424,6 +424,9 @@ static int __bch2_fs_read_write(struct bch_fs *c, bool early)
 
 	set_bit(BCH_FS_ALLOCATOR_RUNNING, &c->flags);
 
+	for_each_rw_member(ca, c, i)
+		bch2_wake_allocator(ca);
+
 	ret = bch2_journal_reclaim_start(&c->journal);
 	if (ret) {
 		bch_err(c, "error starting journal reclaim: %i", ret);
@@ -1000,6 +1003,8 @@ static void bch2_dev_release(struct kobject *kobj)
 
 static void bch2_dev_free(struct bch_dev *ca)
 {
+	bch2_dev_allocator_stop(ca);
+
 	cancel_work_sync(&ca->io_error_work);
 
 	if (ca->kobj.state_in_sysfs &&
@@ -1164,6 +1169,12 @@ static int bch2_dev_alloc(struct bch_fs *c, unsigned dev_idx)
 	if (!ca)
 		goto err;
 
+	if (ca->mi.state == BCH_MEMBER_STATE_RW &&
+	    bch2_dev_allocator_start(ca)) {
+		bch2_dev_free(ca);
+		goto err;
+	}
+
 	bch2_dev_attach(c, ca, dev_idx);
 out:
 	pr_verbose_init(c->opts, "ret %i", ret);