On Mon, Mar 14, 2016 at 08:39:28AM +0100, Jan Kara wrote: > No, that won't be enough. blkdev_issue_flush() is not guaranteed to do > anything to IOs which have not reported completion before > blkdev_issue_flush() was called. Specifically, CFQ will queue submitted bio > in its internal RB tree, following flush request completely bypasses this > tree and goes directly to the disk where it flushes caches. And only later > CFQ decides to schedule async writeback from the flusher thread which is > queued in the RB tree... Oh, right. I am forgetting about the flushing mahchinery rewrite. Thanks for pointing that out. But what we *could* do is to swap those two calls and then in the case where delalloc is enabled, could maintain a list of inodes where we only need to call filemap_fdatawait(), and not initiate writeback for any dirty pages which had been caused by non-allocating writes. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
