• Dave Chinner's avatar
    xfs: struct xfs_buf_log_format isn't variable sized. · 77c1a08f
    Dave Chinner authored
    The struct xfs_buf_log_format wants to think the dirty bitmap is
    variable sized.  In fact, it is variable size on disk simply due to
    the way we map it from the in-memory structure, but we still just
    use a fixed size memory allocation for the in-memory structure.
    
    Hence it makes no sense to set the function up as a variable sized
    structure when we already know it's maximum size, and we always
    allocate it as such. Simplify the structure by making the dirty
    bitmap a fixed sized array and just using the size of the structure
    for the allocation size.
    
    This will make it much simpler to allocate and manipulate an array
    of format structures for discontiguous buffer support.
    
    The previous struct xfs_buf_log_item size according to
    /proc/slabinfo was 224 bytes. pahole doesn't give the same size
    because of the variable size definition. With this modification,
    pahole reports the same as /proc/slabinfo:
    
    	/* size: 224, cachelines: 4, members: 6 */
    
    Because the xfs_buf_log_item size is now determined by the maximum
    supported block size we introduce a dependency on xfs_alloc_btree.h.
    Avoid this dependency by moving the idefines for the maximum block
    sizes supported to xfs_types.h with all the other max/min type
    defines to avoid any new dependencies.
    Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    Signed-off-by: default avatarBen Myers <bpm@sgi.com>
    77c1a08f
xfs_alloc_btree.h 2.94 KB