• Josef Whiter's avatar
    [GFS2] fix hangup when multiple processes are trying to write to the same file · a13cbe37
    Josef Whiter authored
    This fixes a problem I encountered while running bonnie++.  When you have one
    thread that opens a file and starts to write to it, and then another thread that
    tries to open and write to the same file, the second thread will loop forever
    trying to grab the inode lock for that inode.  Basically we come in through
    generic_buffered_file_write, which calls gfs2_prepare_write, which then attempts
    to grab the glock.  Because we don't own the lock, gfs2_prepare_write gets
    GLR_TRYFAILED, which returns AOP_TRUNCATED_PAGE to generic_buffered_file_write.
    At this point generic_buffered_file_write loops around again and immediately
    retries the prepare_write.  This means that the second process never gets off of
    the processor in order to allow the process that holds the lock to finish its
    work and let go of the lock.  This patch makes gfs2_glock_nq schedule() if it
    gets back a GLR_TRYFAILED, which resolves this problem.
    Signed-off-by: default avatarJosef Whiter <jwhiter@redhat.com>
    Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
ops_address.c 19.7 KB