nilfs2: verify btree node after reading

This inserts sanity checks soon after read btree node from disk.  This
allows early detection of broken btree nodes, and helps to narrow down
problems due to file system corruption.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c
index 145f03cd7d3e..edb53fcb7f83 100644
--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -164,10 +164,15 @@ int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
         if (buffer_dirty(bh))
                 return -EEXIST;
 
-        if (buffer_nilfs_node(bh))
+        if (buffer_nilfs_node(bh)) {
+                if (nilfs_btree_broken_node_block(bh)) {
+                        clear_buffer_uptodate(bh);
+                        return -EIO;
+                }
                 nilfs_btnode_mark_dirty(bh);
-        else
+        } else {
                 nilfs_mdt_mark_buffer_dirty(bh);
+        }
         return 0;
 }