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Btrfs: check btree node's nritems

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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>
This commit is contained in:
Liu Bo 2016-08-23 17:37:45 -07:00 committed by Chris Mason
parent 35bbb97fc8
commit 053ab70f06
1 changed files with 16 additions and 0 deletions
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16
fs/btrfs/disk-io.c
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@ -613,6 +613,19 @@ 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",
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)
@ -683,6 +696,9 @@ 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: