[PATCH 4.18 133/197] btrfs: Exit gracefully when chunk map cannot be inserted to the tree

From: Greg Kroah-Hartman
Date: Thu Sep 13 2018 - 10:00:48 EST


4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Qu Wenruo <wqu@xxxxxxxx>

[ Upstream commit 64f64f43c89aca1782aa672e0586f6903c5d8979 ]

It's entirely possible that a crafted btrfs image contains overlapping
chunks.

Although we can't detect such problem by tree-checker, it's not a
catastrophic problem, current extent map can already detect such problem
and return -EEXIST.

We just only need to exit gracefully and fail the mount.

Reported-by: Xu Wen <wen.xu@xxxxxxxxxx>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200409
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/volumes.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6563,10 +6563,14 @@ static int read_one_chunk(struct btrfs_f
write_lock(&map_tree->map_tree.lock);
ret = add_extent_mapping(&map_tree->map_tree, em, 0);
write_unlock(&map_tree->map_tree.lock);
- BUG_ON(ret); /* Tree corruption */
+ if (ret < 0) {
+ btrfs_err(fs_info,
+ "failed to add chunk map, start=%llu len=%llu: %d",
+ em->start, em->len, ret);
+ }
free_extent_map(em);

- return 0;
+ return ret;
}

static void fill_device_from_item(struct extent_buffer *leaf,