bcachefs: bch2_run_explicit_recovery_pass()

This introduces bch2_run_explicit_recovery_pass() and uses it for when
fsck detects that we need to re-run dead snaphots cleanup, and makes
dead snapshot cleanup more like a normal recovery pass.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs.h

@@ -680,7 +680,7 @@ enum bch_write_ref {
 	x(check_snapshot_trees,		PASS_FSCK)						\
 	x(check_snapshots,		PASS_FSCK)						\
 	x(check_subvols,		PASS_FSCK)						\
-	x(delete_dead_snapshots,	PASS_FSCK|PASS_UNCLEAN|PASS_SILENT)			\
+	x(delete_dead_snapshots,	PASS_FSCK|PASS_UNCLEAN)					\
 	x(fs_upgrade_for_subvolumes,	0)							\
 	x(check_inodes,			PASS_FSCK|PASS_UNCLEAN)					\
 	x(check_extents,		PASS_FSCK)						\
@@ -1179,6 +1179,19 @@ static inline bool bch2_dev_exists2(const struct bch_fs *c, unsigned dev)
 	return dev < c->sb.nr_devices && c->devs[dev];
 }
 
+/*
+ * For when we need to rewind recovery passes and run a pass we skipped:
+ */
+static inline int bch2_run_explicit_recovery_pass(struct bch_fs *c,
+						  enum bch_recovery_pass pass)
+{
+	BUG_ON(c->curr_recovery_pass < pass);
+
+	c->recovery_passes_explicit |= BIT_ULL(pass);
+	c->curr_recovery_pass = pass;
+	return -BCH_ERR_restart_recovery;
+}
+
 #define BKEY_PADDED_ONSTACK(key, pad)				\
 	struct { struct bkey_i key; __u64 key ## _pad[pad]; }
 

fs/bcachefs/errcode.h

@@ -157,7 +157,7 @@
 	x(BCH_ERR_fsck,			fsck_errors_not_fixed)			\
 	x(BCH_ERR_fsck,			fsck_repair_unimplemented)		\
 	x(BCH_ERR_fsck,			fsck_repair_impossible)			\
-	x(0,				need_snapshot_cleanup)			\
+	x(0,				restart_recovery)			\
 	x(0,				need_topology_repair)			\
 	x(0,				unwritten_extent_update)		\
 	x(EINVAL,			device_state_not_allowed)		\

fs/bcachefs/fsck.c

@@ -500,7 +500,7 @@ static int snapshots_seen_update(struct bch_fs *c, struct snapshots_seen *s,
 				bch2_btree_ids[btree_id],
 				pos.inode, pos.offset,
 				i->id, n.id, n.equiv);
-			return -BCH_ERR_need_snapshot_cleanup;
+			return bch2_run_explicit_recovery_pass(c, BCH_RECOVERY_PASS_delete_dead_snapshots);
 		}
 	}
 

fs/bcachefs/recovery.c

@@ -1270,11 +1270,8 @@ static int bch2_run_recovery_passes(struct bch_fs *c)
 		c->curr_recovery_pass++;
 	}
 
-	if (bch2_err_matches(ret, BCH_ERR_need_snapshot_cleanup)) {
-		set_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
-		c->curr_recovery_pass = BCH_RECOVERY_PASS_delete_dead_snapshots;
+	if (bch2_err_matches(ret, BCH_ERR_restart_recovery))
 		goto again;
-	}
 
 	return ret;
 }

fs/bcachefs/subvolume.c

@@ -331,8 +331,10 @@ int bch2_mark_snapshot(struct btree_trans *trans,
 		       parent - id - 1 < IS_ANCESTOR_BITMAP)
 			__set_bit(parent - id - 1, t->is_ancestor);
 
-		if (BCH_SNAPSHOT_DELETED(s.v))
+		if (BCH_SNAPSHOT_DELETED(s.v)) {
 			set_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags);
+			c->recovery_passes_explicit |= BIT_ULL(BCH_RECOVERY_PASS_delete_dead_snapshots);
+		}
 	} else {
 		memset(t, 0, sizeof(*t));
 	}
@@ -1302,9 +1304,6 @@ int bch2_delete_dead_snapshots(struct bch_fs *c)
 	u32 i, id;
 	int ret = 0;
 
-	if (!test_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags))
-		return 0;
-
 	if (!test_bit(BCH_FS_STARTED, &c->flags)) {
 		ret = bch2_fs_read_write_early(c);
 		if (ret) {
@@ -1399,6 +1398,7 @@ static void bch2_delete_dead_snapshots_work(struct work_struct *work)
 {
 	struct bch_fs *c = container_of(work, struct bch_fs, snapshot_delete_work);
 
+	if (test_bit(BCH_FS_HAVE_DELETED_SNAPSHOTS, &c->flags))
 		bch2_delete_dead_snapshots(c);
 	bch2_write_ref_put(c, BCH_WRITE_REF_delete_dead_snapshots);
 }