On Fri, Mar 17, 2017 at 01:53:46PM +0000, Rick Macklem wrote: > Well, I don't mind adding ncl_flush(), but it shouldn't be > necessary. I actually had it in the first > rendition of the patch, but took it out because it should happen > on the VOP_CLOSE() if any writing to the buffer cache happened > and that code hasn't changed in many years. Dirty pages are flushed by writes, so if we have a set of dirty pages and async vm_object_page_clean() is called on the vnode' vm_object, we get a bunch of delayed-write AKA dirty buffers. This is possible even after VOP_CLOSE() was done, e.g. by syncer performing regular run involving vfs_msync().
I agree that the patch would not create new dirty buffers, but it is possible to get them by other means. > > What the patch was missing was updating n_mtime after the dirty > page flush. > > Btw, a flush without OBJPC_SYNC happens when the file is VOP_CLOSE()'d > unless the default value of vfs.nfs.clean_[ages_on_close is changed, which > I think is why the 1sec resolution always seemed to work, at least for the > example where there was an munmap before close. > > Attached is an updated version with that in it, rick _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
