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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2010-07-16 23:52:40 +0900
committerRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2010-07-23 10:02:13 +0900
commit1d5385b9f30ae43209459db424416a3e1d8f2bde (patch)
tree202a19586853da9ec598645b5d289d4a0164b232 /fs/nilfs2/btree.c
parentcfa913a5077f7619869b2b4d1bf23ccb4f8b3d7b (diff)
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>
Diffstat (limited to 'fs/nilfs2/btree.c')
-rw-r--r--fs/nilfs2/btree.c50
1 files changed, 47 insertions, 3 deletions
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 386356707f9..6c9ec566d00 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -71,17 +71,24 @@ static int nilfs_btree_get_block(const struct nilfs_btree *btree, __u64 ptr,
{
struct address_space *btnc =
&NILFS_BMAP_I((struct nilfs_bmap *)btree)->i_btnode_cache;
+ struct buffer_head *bh;
int err;
err = nilfs_btnode_submit_block(btnc, ptr, 0, bhp);
if (err)
return err == -EEXIST ? 0 : err;
- wait_on_buffer(*bhp);
- if (!buffer_uptodate(*bhp)) {
- brelse(*bhp);
+ bh = *bhp;
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(bh)) {
+ brelse(bh);
return -EIO;
}
+ if (nilfs_btree_broken_node_block(bh)) {
+ clear_buffer_uptodate(bh);
+ brelse(bh);
+ return -EINVAL;
+ }
return 0;
}
@@ -382,6 +389,43 @@ static int nilfs_btree_node_lookup(const struct nilfs_btree_node *node,
return s == 0;
}
+/**
+ * nilfs_btree_node_broken - verify consistency of btree node
+ * @node: btree node block to be examined
+ * @size: node size (in bytes)
+ * @blocknr: block number
+ *
+ * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
+ */
+static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
+ size_t size, sector_t blocknr)
+{
+ int level, flags, nchildren;
+ int ret = 0;
+
+ level = nilfs_btree_node_get_level(node);
+ flags = nilfs_btree_node_get_flags(node);
+ nchildren = nilfs_btree_node_get_nchildren(node);
+
+ if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
+ level >= NILFS_BTREE_LEVEL_MAX ||
+ (flags & NILFS_BTREE_NODE_ROOT) ||
+ nchildren < 0 ||
+ nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) {
+ printk(KERN_CRIT "NILFS: bad btree node (blocknr=%llu): "
+ "level = %d, flags = 0x%x, nchildren = %d\n",
+ (unsigned long long)blocknr, level, flags, nchildren);
+ ret = 1;
+ }
+ return ret;
+}
+
+int nilfs_btree_broken_node_block(struct buffer_head *bh)
+{
+ return nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
+ bh->b_size, bh->b_blocknr);
+}
+
static inline struct nilfs_btree_node *
nilfs_btree_get_root(const struct nilfs_btree *btree)
{