bcachefs: Scan for old btree nodes if necessary on mount

We dropped support for !BTREE_NODE_NEW_EXTENT_OVERWRITE but it turned
out there were people who still had filesystems with btree nodes in that
format in the wild. This adds a new compat feature that indicates we've
scanned for and rewritten nodes in the old format, and does that scan at
mount time if the option isn't set.

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

1 files changed, 16 insertions, 0 deletions

diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index 0aeaaadbf3f8..e322dc35f992 100644
--- a/fs/bcachefs/recovery.c
+++ b/fs/bcachefs/recovery.c
@@ -16,6 +16,7 @@
 #include "journal_io.h"
 #include "journal_reclaim.h"
 #include "journal_seq_blacklist.h"
+#include "move.h"
 #include "quota.h"
 #include "recovery.h"
 #include "replicas.h"
@@ -1200,6 +1201,20 @@ use_clean:
 		bch_verbose(c, "quotas done");
 	}
 
+	if (!(c->sb.compat & (1ULL << BCH_COMPAT_FEAT_EXTENTS_ABOVE_BTREE_UPDATES_DONE))) {
+		struct bch_move_stats stats = { 0 };
+
+		bch_verbose(c, "scanning for old btree nodes");
+		ret = bch2_fs_read_write(c);
+		if (ret)
+			goto err;
+
+		ret = bch2_scan_old_btree_nodes(c, &stats);
+		if (ret)
+			goto err;
+		bch_verbose(c, "scanning for old btree nodes done");
+	}
+
 	mutex_lock(&c->sb_lock);
 	if (c->opts.version_upgrade) {
 		if (c->sb.version < bcachefs_metadata_version_new_versioning)
@@ -1271,6 +1286,7 @@ int bch2_fs_initialize(struct bch_fs *c)
 		le16_to_cpu(bcachefs_metadata_version_current);
 	c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_atomic_nlink;
 	c->disk_sb.sb->features[0] |= BCH_SB_FEATURES_ALL;
+	c->disk_sb.sb->compat[0] |= 1ULL << BCH_COMPAT_FEAT_EXTENTS_ABOVE_BTREE_UPDATES_DONE;
 
 	bch2_write_super(c);
 	mutex_unlock(&c->sb_lock);