bcachefs: New and improved topology repair code

This splits out btree topology repair into a separate pass, and makes
some improvements:
 - When we have to pick which of two overlapping nodes to drop keys
   from, we use the btree node header sequence number to preserve the
   newer node

 - the gc code has been changed so that it doesn't bail out if we're
   continuing/ignoring on fsck error - this way the dump tool can skip
   running the repair pass but still walk all reachable metadata

 - add a new superblock flag indicating when a filesystem is known to
   have btree topology issues, and the topology repair pass should be
   run

 - changing the start/end of a node might mean keys in that node have to
   be deleted: this patch handles that better by splitting it out into a
   separate function and running it explicitly in the topology repair
   code, previously those keys were only being dropped when the btree
   node was read in.

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

1 files changed, 15 insertions, 3 deletions

diff --git a/fs/bcachefs/error.c b/fs/bcachefs/error.c
index a8ee1db8aa39..90c3b986c264 100644
--- a/fs/bcachefs/error.c
+++ b/fs/bcachefs/error.c
@@ -25,6 +25,13 @@ bool bch2_inconsistent_error(struct bch_fs *c)
 	}
 }
 
+void bch2_topology_error(struct bch_fs *c)
+{
+	set_bit(BCH_FS_TOPOLOGY_ERROR, &c->flags);
+	if (test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags))
+		bch2_inconsistent_error(c);
+}
+
 void bch2_fatal_error(struct bch_fs *c)
 {
 	if (bch2_fs_emergency_read_only(c))
@@ -74,9 +81,13 @@ enum fsck_err_ret bch2_fsck_err(struct bch_fs *c, unsigned flags,
 		vprintk(fmt, args);
 		va_end(args);
 
-		return bch2_inconsistent_error(c)
-			? FSCK_ERR_EXIT
-			: FSCK_ERR_FIX;
+		if (c->opts.errors == BCH_ON_ERROR_continue) {
+			bch_err(c, "fixing");
+			return FSCK_ERR_FIX;
+		} else {
+			bch2_inconsistent_error(c);
+			return FSCK_ERR_EXIT;
+		}
 	}
 
 	mutex_lock(&c->fsck_error_lock);
@@ -146,6 +157,7 @@ print:
 		set_bit(BCH_FS_ERRORS_FIXED, &c->flags);
 		return FSCK_ERR_FIX;
 	} else {
+		set_bit(BCH_FS_ERRORS_NOT_FIXED, &c->flags);
 		set_bit(BCH_FS_ERROR, &c->flags);
 		return c->opts.fix_errors == FSCK_OPT_EXIT ||
 			!(flags & FSCK_CAN_IGNORE)