4.4-stable review patch. If anyone has any objections, please let me know.
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From: Liu Bo bo.li.liu@oracle.com
commit 053ab70f0604224c7893b43f9d9d5efa283580d6 upstream.
When btree node (level = 1) has nritems which equals to zero, we can end up with panic due to insert_ptr()'s
BUG_ON(slot > nritems);
where slot is 1 and nritems is 0, as copy_for_split() calls insert_ptr(.., path->slots[1] + 1, ...);
A invalid value results in the whole mess, this adds the check for btree's node nritems so that we stop reading block when when something is wrong.
Signed-off-by: Liu Bo bo.li.liu@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Chris Mason clm@fb.com Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/disk-io.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
--- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -609,6 +609,19 @@ static noinline int check_leaf(struct bt return 0; }
+static int check_node(struct btrfs_root *root, struct extent_buffer *node) +{ + unsigned long nr = btrfs_header_nritems(node); + + if (nr == 0 || nr > BTRFS_NODEPTRS_PER_BLOCK(root)) { + btrfs_crit(root->fs_info, + "corrupt node: block %llu root %llu nritems %lu", + node->start, root->objectid, nr); + return -EIO; + } + return 0; +} + static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio, u64 phy_offset, struct page *page, u64 start, u64 end, int mirror) @@ -680,6 +693,9 @@ static int btree_readpage_end_io_hook(st ret = -EIO; }
+ if (found_level > 0 && check_node(root, eb)) + ret = -EIO; + if (!ret) set_extent_buffer_uptodate(eb); err: