• Miao Xie's avatar
    Btrfs: Fix misuse of chunk mutex · 2196d6e8
    Miao Xie authored
    There were several problems about chunk mutex usage:
    - Lock chunk mutex when updating metadata. It would cause the nested
      deadlock because updating metadata might need allocate new chunks
      that need acquire chunk mutex. We remove chunk mutex at this case,
      because b-tree lock and other lock mechanism can help us.
    - ABBA deadlock occured between device_list_mutex and chunk_mutex.
      When we update device status, we must acquire device_list_mutex at the
      beginning, and then we might get chunk_mutex during the device status
      update because we need allocate new chunks for metadata COW. But at
      most place, we acquire chunk_mutex at first and then acquire device list
      mutex. We need change the lock order.
    - Some place we needn't acquire chunk_mutex. For example we needn't get
      chunk_mutex when we free a empty seed fs_devices structure.
    Signed-off-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
    Signed-off-by: default avatarChris Mason <clm@fb.com>
    2196d6e8
extent-tree.c 254 KB