buffer cache/chunk cache (cont’)
xfs_write gets “chunk” to write
- chunk may already exist and have disk blocks
- chunk may be “delayed allocate”
daemons that write buffers:
- bdflush flushes dirty buffers (calls xfs_strategy)
- xfsd flushes buffers which need allocation
xfs_strategy called to write buffer
- queues for xfsd if allocation needed
- writes buffer with disk storage