On Thu, Aug 10, 2023 at 05:52:25PM +0200, Christoph Hellwig wrote: > On Thu, Aug 10, 2023 at 04:22:15PM +0100, Matthew Wilcox wrote: > > > blkdev_issue_flush(mp->m_logdev_targp->bt_bdev); > > > invalidate_bdev(mp->m_logdev_targp->bt_bdev); > > > > While I have no complaints with this as a commit message, it's just too > > verbose for an inline comment, IMO. Something pithier and more generic > > would seem appropriate. How about: > > > > /* > > * Prevent userspace (eg blkid or xfs_db) from seeing stale data. > > * XFS is not coherent with the bdev's page cache. > > */ > > Well, this completely misses the point. The point is that XFS should > never have to invalidate the page cache because it's not using it, > but it has to due to weird races. I tried to condese the message but > I could not come up with a good one that's not losing information. Agreed -- it took me a while to set up an arm64 box with just the right debugging info to figure out why certain fstests were flaky. I do think it's useful (despite my other reply to willy) to retain the defect details for hard-to-reproduce errors, and the only way to do that without encountering the dead url problem is to dump it in a huge commit message or a comment. (Too bad there's no way to have a commit whose code comments reference the commit id of that commit to say "Hey, you need to read this commit before you touch this line"...) --D
