[PATCH v2] Btrfs: check btree node's nritems
From: Liu Bo <hidden>
Date: 2016-08-24 00:34:05
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
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 <redacted>
---
v2: - remove unnecessary "noinline"
- fix to do the proper check as BTRFS_NODEPTRS_PER_BLOCK(root) is inclusive and nr is unsigned.
fs/btrfs/disk-io.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 90f57fa..682816d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c@@ -633,6 +633,19 @@ static noinline int check_leaf(struct btrfs_root *root, 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\n", + 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)
@@ -703,6 +716,9 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio, ret = -EIO; } + if (found_level > 0 && check_node(root, eb)) + ret = -EIO; + if (!ret) set_extent_buffer_uptodate(eb); err:
--
2.5.5