Btrfs: Use map_private_extent_buffer during generic_bin_search
It is possible that generic_bin_search will be called on a tree block
that has not been locked. This happens because cache_block_block skips
locking on the tree blocks.
Since the tree block isn't locked, we aren't allowed to change
the extent_buffer->map_token field. Using map_private_extent_buffer
avoids any changes to the internal extent buffer fields.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 7449ecf..607f5ff 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3471,6 +3471,7 @@
unmap_extent_buffer(eb, eb->map_token, km);
eb->map_token = NULL;
save = 1;
+ WARN_ON(!mutex_is_locked(&eb->mutex));
}
err = map_private_extent_buffer(eb, start, min_len, token, map,
map_start, map_len, km);