bcachefs: Go RW before check_alloc_info()

It's possible to do btree updates before going RW by adding them to the
list of updates for journal replay to do, but this is limited by what
fits in RAM. This patch switches the second alloc info phase to run
after going RW - btree_gc has already ensured the alloc btree itself is
correct - and tweaks the allocation path to deal with the potential
small inconsistencies.

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

1 files changed, 22 insertions, 10 deletions

diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index 534dbf197d58..ba14cfe06515 100644
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -316,28 +316,34 @@ static struct open_bucket *try_alloc_bucket(struct btree_trans *trans, struct bc
 
 	a = bch2_alloc_to_v4(k, &a_convert);
 
-	if (genbits != (alloc_freespace_genbits(*a) >> 56)) {
-		prt_printf(&buf, "bucket in freespace btree with wrong genbits (got %u should be %llu)\n"
-		       "  freespace key ",
-		       genbits, alloc_freespace_genbits(*a) >> 56);
+	if (a->data_type != BCH_DATA_free) {
+		if (!test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags)) {
+			ob = NULL;
+			goto err;
+		}
+
+		prt_printf(&buf, "non free bucket in freespace btree\n"
+		       "  freespace key ");
 		bch2_bkey_val_to_text(&buf, c, freespace_k);
 		prt_printf(&buf, "\n  ");
 		bch2_bkey_val_to_text(&buf, c, k);
 		bch2_trans_inconsistent(trans, "%s", buf.buf);
 		ob = ERR_PTR(-EIO);
 		goto err;
-
 	}
 
-	if (a->data_type != BCH_DATA_free) {
-		prt_printf(&buf, "non free bucket in freespace btree\n"
-		       "  freespace key ");
+	if (genbits != (alloc_freespace_genbits(*a) >> 56) &&
+	    test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags)) {
+		prt_printf(&buf, "bucket in freespace btree with wrong genbits (got %u should be %llu)\n"
+		       "  freespace key ",
+		       genbits, alloc_freespace_genbits(*a) >> 56);
 		bch2_bkey_val_to_text(&buf, c, freespace_k);
 		prt_printf(&buf, "\n  ");
 		bch2_bkey_val_to_text(&buf, c, k);
 		bch2_trans_inconsistent(trans, "%s", buf.buf);
 		ob = ERR_PTR(-EIO);
 		goto err;
+
 	}
 
 	ob = __try_alloc_bucket(c, ca, b, reserve, a, s, cl);
@@ -505,6 +511,7 @@ static struct open_bucket *bch2_bucket_alloc_trans(struct btree_trans *trans,
 {
 	struct bch_fs *c = trans->c;
 	struct open_bucket *ob = NULL;
+	bool freespace = READ_ONCE(ca->mi.freespace_initialized);
 	u64 avail;
 	struct bucket_alloc_state s = { 0 };
 	bool waiting = false;
@@ -543,13 +550,18 @@ again:
 		if (ob)
 			return ob;
 	}
-
-	ob = likely(ca->mi.freespace_initialized)
+alloc:
+	ob = likely(freespace)
 		? bch2_bucket_alloc_freelist(trans, ca, reserve, &s, cl)
 		: bch2_bucket_alloc_early(trans, ca, reserve, &s, cl);
 
 	if (s.skipped_need_journal_commit * 2 > avail)
 		bch2_journal_flush_async(&c->journal, NULL);
+
+	if (!ob && freespace && !test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags)) {
+		freespace = false;
+		goto alloc;
+	}
 err:
 	if (!ob)
 		ob = ERR_PTR(-BCH_ERR_no_buckets_found);