• Aurelien Aptel's avatar
    CIFS: keep FileInfo handle live during oplock break · b98749ca
    Aurelien Aptel authored
    In the oplock break handler, writing pending changes from pages puts
    the FileInfo handle. If the refcount reaches zero it closes the handle
    and waits for any oplock break handler to return, thus causing a deadlock.
    
    To prevent this situation:
    
    * We add a wait flag to cifsFileInfo_put() to decide whether we should
      wait for running/pending oplock break handlers
    
    * We keep an additionnal reference of the SMB FileInfo handle so that
      for the rest of the handler putting the handle won't close it.
      - The ref is bumped everytime we queue the handler via the
        cifs_queue_oplock_break() helper.
      - The ref is decremented at the end of the handler
    
    This bug was triggered by xfstest 464.
    
    Also important fix to address the various reports of
    oops in smb2_push_mandatory_locks
    Signed-off-by: default avatarAurelien Aptel <aaptel@suse.com>
    Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
    Reviewed-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
    CC: Stable <stable@vger.kernel.org>
    b98749ca
misc.c 26.3 KB