nilfs2: add sanity check in nilfs_btree_add_dirty_buffer
According to the report titled "problem with nilfs_cleanerd" from
Łukasz Wójcicki, nilfs_btree_lookup_dirty_buffers or
nilfs_btree_add_dirty_buffer got memory violation during garbage
collection.
This could happen if a level field of given btree node buffer is
incorrect, which is a crucial internal bug.
This inserts a sanity check to figure out the problem.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index b27a342..3863567 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -1920,6 +1920,18 @@
node = (struct nilfs_btree_node *)bh->b_data;
key = nilfs_btree_node_get_key(node, 0);
level = nilfs_btree_node_get_level(node);
+ if (level < NILFS_BTREE_LEVEL_NODE_MIN ||
+ level >= NILFS_BTREE_LEVEL_MAX) {
+ dump_stack();
+ printk(KERN_WARNING
+ "%s: invalid btree level: %d (key=%llu, ino=%lu, "
+ "blocknr=%llu)\n",
+ __func__, level, (unsigned long long)key,
+ NILFS_BMAP_I(&btree->bt_bmap)->vfs_inode.i_ino,
+ (unsigned long long)bh->b_blocknr);
+ return;
+ }
+
list_for_each(head, &lists[level]) {
cbh = list_entry(head, struct buffer_head, b_assoc_buffers);
cnode = (struct nilfs_btree_node *)cbh->b_data;