[...] > I have also noticed that XFS bizarrely has its own layer of > recovery on top of that of the Linux IO subsystems and of the > device itself: > https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_file_systems/configuring-xfs-error-behavior_managing-file-systems > https://elixir.bootlin.com/linux/v5.13.5/source/fs/xfs/xfs_buf.c#L1264 Some people have been proposing to do the same with MD RAID, and some similar layer sometimes is embedded in the firmware of hardware RAID host adapters. Consider this scenario (include the relevant error handling and timeouts): * The device firmware does physical operation retries. * The Linux IO subsystem does device operation retries. * MD RAID does Linux IO operation retries. * XFS does MD RAID IO operation retries. Is there something weird with this? BTW there is something similar with read ahead or write behind: sometimes several software layers assume that lower software layers are doing too little of it, and do their own additional read ahead or write behind.
