Neil Brown writes: > [...] > Thus the general sequence might be: > > a/ issue all "preceding writes". > b/ issue the commit write with BIO_RW_BARRIER > c/ wait for the commit to complete. > If it was successful - done. > If it failed other than with EOPNOTSUPP, abort > else continue > d/ wait for all 'preceding writes' to complete > e/ call blkdev_issue_flush > f/ issue commit write without BIO_RW_BARRIER > g/ wait for commit write to complete > if it failed, abort > h/ call blkdev_issue > DONE > > steps b and c can be left out if it is known that the device does not > support barriers. The only way to discover this to try and see if it > fails. > > I don't think any filesystem follows all these steps. It seems that steps b/ -- h/ are quite generic, and can be implemented once in a generic code (with some synchronization mechanism like wait-queue at d/). Nikita. [...] > > Thank you for your attention. > > NeilBrown > Nikita. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
