Hi group, As part of enabling maximum-reliability (at cost of performance) workarounds for MMC media whose controllers employ a scheme, where there is usually a small (flash-page sized) and a large (erase-block sized) buffer, I needed reliable write support. As per Arnd's feedback, I've split the reliable write support out by itself. I believe other people were going to look at this as well (https://wiki.linaro.org/WorkingGroups/KernelConsolidation/Specs/StoragePerfEMMC).
The patch provides a mechanism by which reliable writes can be enabled if they are supported, and enables them for REQ_FUA/REQ_META write transfers. REQ_FUA/REQ_FLUSH is a replacement for barrier bios, which were broken before anyway (couldn't handle partial completions, which are what's going to happen for legacy reliable write support). REQ_FUA is a flag a bio submitted from the filesystem and will make sure that I/O completion for this request is only signaled after the data has been committed to non-volatile storage. REQ_META are supposed to be used by filesystems to mark bios that contain metadata. The patch is against linux-next and was tested with a Toshiba MMC08G (legacy reliable write support) eMMC on x64. ToC: [comments] MMC: Reliable write support. Thanks ahead of time, A -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
