• Chris Mason's avatar
    Btrfs: hash_lock is no longer needed · c487685d
    Chris Mason authored
    Before metadata is written to disk, it is updated to reflect that writeout
    has begun.  Once this update is done, the block must be cow'd before it
    can be modified again.
    This update was originally synchronized by using a per-fs spinlock.  Today
    the buffers for the metadata blocks are locked before writeout begins,
    and everyone that tests the flag has the buffer locked as well.
    So, the per-fs spinlock (called hash_lock for no good reason) is no
    longer required.
    Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>