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  • Benjamin Marzinski's avatar
    [GFS2] flush the glock completely in inode_go_sync · b524fe64
    Benjamin Marzinski authored
    
    
    Fix for bz #231910
    When filemap_fdatawrite() is called on the inode mapping in data=ordered mode,
    it will add the glock to the log. In inode_go_sync(), if you do the
    gfs2_log_flush() before this, after the filemap_fdatawrite() call, the glock
    and its associated data buffers will be on the log again. This means you can
    demote a lock from exclusive, without having it flushed from the log. The
    attached patch simply moves the gfs2_log_flush up to after the
    filemap_fdatawrite() call.
    
    Originally, I tried moving the gfs2_log_flush to after gfs2_meta_sync(), but
    that caused me to trip the following assert.
    
    GFS2: fsid=cypher-36:test.0: fatal: assertion "!buffer_busy(bh)" failed
    GFS2: fsid=cypher-36:test.0:   function = gfs2_ail_empty_gl, file = fs/gfs2/glops.c, line = 61
    
    It appears that gfs2_log_flush() puts some of the glocks buffers in the busy
    state and the filemap_fdatawrite() call is necessary to flush them. This makes
    me worry slightly that a related problem could happen because of moving the
    gfs2_log_flush() after the initial filemap_fdatawrite(), but I assume that
    gfs2_ail_empty_gl() would catch that case as well.
    
    Signed-off-by: default avatarBenjamin E. Marzinski <bmarzins@redhat.com>
    Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
    b524fe64