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>

5 files changed, 62 insertions, 38 deletions

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index 0939200e6d1a..ae6ae78a2618 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -800,6 +800,7 @@ static int bch2_bucket_do_index(struct btree_trans *trans,
 		goto err;
 
 	if (ca->mi.freespace_initialized &&
+	    test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags) &&
 	    bch2_trans_inconsistent_on(old.k->type != old_type, trans,
 			"incorrect key when %s %s btree (got %s should be %s)\n"
 			"  for %s",
@@ -1649,21 +1650,28 @@ static int bch2_discard_one_bucket(struct btree_trans *trans,
 		goto write;
 	}
 
-	if (bch2_trans_inconsistent_on(a->v.journal_seq > c->journal.flushed_seq_ondisk, trans,
-			"clearing need_discard but journal_seq %llu > flushed_seq %llu\n"
-			"%s",
-			a->v.journal_seq,
-			c->journal.flushed_seq_ondisk,
-			(bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
-		ret = -EIO;
+	if (a->v.journal_seq > c->journal.flushed_seq_ondisk) {
+		if (test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags)) {
+			bch2_trans_inconsistent(trans,
+				"clearing need_discard but journal_seq %llu > flushed_seq %llu\n"
+				"%s",
+				a->v.journal_seq,
+				c->journal.flushed_seq_ondisk,
+				(bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+			ret = -EIO;
+		}
 		goto out;
 	}
 
-	if (bch2_trans_inconsistent_on(a->v.data_type != BCH_DATA_need_discard, trans,
-			"bucket incorrectly set in need_discard btree\n"
-			"%s",
-			(bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
-		ret = -EIO;
+	if (a->v.data_type != BCH_DATA_need_discard) {
+		if (test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags)) {
+			bch2_trans_inconsistent(trans,
+				"bucket incorrectly set in need_discard btree\n"
+				"%s",
+				(bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+			ret = -EIO;
+		}
+
 		goto out;
 	}
 
diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index 86acc7d3b4c6..2010a9af0eb2 100644
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -312,28 +312,34 @@ 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;
+
 	}
 
 	if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
@@ -506,8 +512,8 @@ 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_initialized = READ_ONCE(ca->mi.freespace_initialized);
-	u64 start = freespace_initialized ? 0 : ca->bucket_alloc_trans_early_cursor;
+	bool freespace = READ_ONCE(ca->mi.freespace_initialized);
+	u64 start = freespace ? 0 : ca->bucket_alloc_trans_early_cursor;
 	u64 avail;
 	struct bucket_alloc_state s = { .cur_bucket = start };
 	bool waiting = false;
@@ -546,20 +552,25 @@ 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_initialized && start) {
+	if (!ob && !freespace && start) {
 		start = s.cur_bucket = 0;
-		goto again;
+		goto alloc;
+	}
+
+	if (!ob && freespace && !test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags)) {
+		freespace = false;
+		goto alloc;
 	}
 
-	if (!freespace_initialized)
+	if (!freespace)
 		ca->bucket_alloc_trans_early_cursor = s.cur_bucket;
 err:
 	if (!ob)
diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 7d4367f93b5c..405823d1cfab 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -242,6 +242,9 @@ btree:
 	    memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp))) {
 		struct printbuf buf = PRINTBUF;
 
+		if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
+			goto err;
+
 		prt_printf(&buf, "backpointer not found when deleting");
 		prt_newline(&buf);
 		printbuf_indent_add(&buf, 2);
@@ -262,10 +265,8 @@ btree:
 		bch2_bkey_val_to_text(&buf, c, orig_k);
 
 		bch_err(c, "%s", buf.buf);
-		if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
-			bch2_inconsistent_error(c);
-			ret = -EIO;
-		}
+		bch2_inconsistent_error(c);
+		ret = -EIO;
 		printbuf_exit(&buf);
 		goto err;
 	}
diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index 7f479cdc7069..71f51459872d 100644
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -549,6 +549,7 @@ enum {
 	/* fsck passes: */
 	BCH_FS_TOPOLOGY_REPAIR_DONE,
 	BCH_FS_INITIAL_GC_DONE,		/* kill when we enumerate fsck passes */
+	BCH_FS_CHECK_ALLOC_DONE,
 	BCH_FS_CHECK_LRUS_DONE,
 	BCH_FS_CHECK_BACKPOINTERS_DONE,
 	BCH_FS_CHECK_ALLOC_TO_LRU_REFS_DONE,
diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index aec98a98a39a..0ad2bb2aa039 100644
--- a/fs/bcachefs/recovery.c
+++ b/fs/bcachefs/recovery.c
@@ -1246,13 +1246,6 @@ use_clean:
 
 		set_bit(BCH_FS_INITIAL_GC_DONE, &c->flags);
 
-		bch_info(c, "checking need_discard and freespace btrees");
-		err = "error checking need_discard and freespace btrees";
-		ret = bch2_check_alloc_info(c);
-		if (ret)
-			goto err;
-		bch_verbose(c, "done checking need_discard and freespace btrees");
-
 		if (c->sb.version < bcachefs_metadata_version_snapshot_2) {
 			err = "error creating root snapshot node";
 			ret = bch2_fs_initialize_subvolumes(c);
@@ -1277,6 +1270,15 @@ use_clean:
 		if (c->opts.verbose || !c->sb.clean)
 			bch_info(c, "journal replay done");
 
+		bch_info(c, "checking need_discard and freespace btrees");
+		err = "error checking need_discard and freespace btrees";
+		ret = bch2_check_alloc_info(c);
+		if (ret)
+			goto err;
+		bch_verbose(c, "done checking need_discard and freespace btrees");
+
+		set_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags);
+
 		bch_info(c, "checking lrus");
 		err = "error checking lrus";
 		ret = bch2_check_lrus(c);
@@ -1316,6 +1318,7 @@ use_clean:
 		set_bit(BCH_FS_CHECK_ALLOC_TO_LRU_REFS_DONE, &c->flags);
 	} else {
 		set_bit(BCH_FS_INITIAL_GC_DONE, &c->flags);
+		set_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags);
 		set_bit(BCH_FS_CHECK_LRUS_DONE, &c->flags);
 		set_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags);
 		set_bit(BCH_FS_CHECK_ALLOC_TO_LRU_REFS_DONE, &c->flags);