ubifs: Do not update inode size in-place in authenticated mode

In authenticated mode we cannot fixup the inode sizes in-place
during recovery as this would invalidate the hashes and HMACs
we stored for this inode.

Instead, we just write the updated inodes to the journal. We can
only do this after ubifs_rcvry_gc_commit() is done though, so for
authenticated mode call ubifs_recover_size() after
ubifs_rcvry_gc_commit() and not vice versa as normally done.

Calling ubifs_recover_size() after ubifs_rcvry_gc_commit() has the
drawback that after a commit the size fixup information is gone, so
when a powercut happens while recovering from another powercut
we may lose some data written right before the first powercut.
This is why we only do this in authenticated mode and leave the
behaviour for unauthenticated mode untouched.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 29 insertions, 9 deletions

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 2722ca077d23..e2964ce81dee 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1378,12 +1378,21 @@ static int mount_ubifs(struct ubifs_info *c)
 		}
 
 		if (c->need_recovery) {
-			err = ubifs_recover_size(c);
-			if (err)
-				goto out_orphans;
+			if (!ubifs_authenticated(c)) {
+				err = ubifs_recover_size(c, true);
+				if (err)
+					goto out_orphans;
+			}
+
 			err = ubifs_rcvry_gc_commit(c);
 			if (err)
 				goto out_orphans;
+
+			if (ubifs_authenticated(c)) {
+				err = ubifs_recover_size(c, false);
+				if (err)
+					goto out_orphans;
+			}
 		} else {
 			err = take_gc_lnum(c);
 			if (err)
@@ -1402,7 +1411,7 @@ static int mount_ubifs(struct ubifs_info *c)
 		if (err)
 			goto out_orphans;
 	} else if (c->need_recovery) {
-		err = ubifs_recover_size(c);
+		err = ubifs_recover_size(c, false);
 		if (err)
 			goto out_orphans;
 	} else {
@@ -1629,9 +1638,11 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 		err = ubifs_write_rcvrd_mst_node(c);
 		if (err)
 			goto out;
-		err = ubifs_recover_size(c);
-		if (err)
-			goto out;
+		if (!ubifs_authenticated(c)) {
+			err = ubifs_recover_size(c, true);
+			if (err)
+				goto out;
+		}
 		err = ubifs_clean_lebs(c, c->sbuf);
 		if (err)
 			goto out;
@@ -1697,10 +1708,19 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 			goto out;
 	}
 
-	if (c->need_recovery)
+	if (c->need_recovery) {
 		err = ubifs_rcvry_gc_commit(c);
-	else
+		if (err)
+			goto out;
+
+		if (ubifs_authenticated(c)) {
+			err = ubifs_recover_size(c, false);
+			if (err)
+				goto out;
+		}
+	} else {
 		err = ubifs_leb_unmap(c, c->gc_lnum);
+	}
 	if (err)
 		goto out;