bcachefs: Interior btree updates are now fully transactional

We now update the alloc info (bucket sector counts) atomically with
journalling the update to the interior btree nodes, and we also set new
btree roots atomically with the journalled part of the btree update.

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

1 files changed, 18 insertions, 2 deletions

diff --git a/fs/bcachefs/journal_io.c b/fs/bcachefs/journal_io.c
index 421fde39ac0e..1724c80b323c 100644
--- a/fs/bcachefs/journal_io.c
+++ b/fs/bcachefs/journal_io.c
@@ -2,6 +2,7 @@
 #include "bcachefs.h"
 #include "alloc_foreground.h"
 #include "btree_io.h"
+#include "btree_update_interior.h"
 #include "buckets.h"
 #include "checksum.h"
 #include "error.h"
@@ -992,8 +993,23 @@ void bch2_journal_write(struct closure *cl)
 
 	j->write_start_time = local_clock();
 
-	start	= vstruct_last(jset);
-	end	= bch2_journal_super_entries_add_common(c, start,
+	/*
+	 * New btree roots are set by journalling them; when the journal entry
+	 * gets written we have to propagate them to c->btree_roots
+	 *
+	 * But, every journal entry we write has to contain all the btree roots
+	 * (at least for now); so after we copy btree roots to c->btree_roots we
+	 * have to get any missing btree roots and add them to this journal
+	 * entry:
+	 */
+
+	bch2_journal_entries_to_btree_roots(c, jset);
+
+	start = end = vstruct_last(jset);
+
+	end	= bch2_btree_roots_to_journal_entries(c, jset->start, end);
+
+	end	= bch2_journal_super_entries_add_common(c, end,
 						le64_to_cpu(jset->seq));
 	u64s	= (u64 *) end - (u64 *) start;
 	BUG_ON(u64s > j->entry_u64s_reserved);