UBIFS: TNC / GC race fixes
- update GC sequence number if any nodes may have been moved
even if GC did not finish the LEB
- don't ignore error return when reading
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index 13f1019..02aba36 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -334,15 +334,15 @@
err = move_nodes(c, sleb);
if (err)
- goto out;
+ goto out_inc_seq;
err = gc_sync_wbufs(c);
if (err)
- goto out;
+ goto out_inc_seq;
err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);
if (err)
- goto out;
+ goto out_inc_seq;
/* Allow for races with TNC */
c->gced_lnum = lnum;
@@ -369,6 +369,14 @@
out:
ubifs_scan_destroy(sleb);
return err;
+
+out_inc_seq:
+ /* We may have moved at least some nodes so allow for races with TNC */
+ c->gced_lnum = lnum;
+ smp_wmb();
+ c->gc_seq += 1;
+ smp_wmb();
+ goto out;
}
/**
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index 7da209a..7634c59 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -1476,7 +1476,7 @@
}
err = fallible_read_node(c, key, &zbr, node);
- if (maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
+ if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
/*
* The node may have been GC'ed out from under us so try again
* while keeping the TNC mutex locked.