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

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

From: Qu Wenruo <w...@suse.com>

[ 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...@gatech.edu>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200409
Signed-off-by: Qu Wenruo <w...@suse.com>
Reviewed-by: David Sterba <dste...@suse.com>
Signed-off-by: David Sterba <dste...@suse.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 fs/btrfs/volumes.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6492,10 +6492,14 @@ 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,


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