Date: Fri, 17 Mar 2017 16:19:17 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: Dimitry Andric <dim@FreeBSD.org>, Ian Lepore <ian@FreeBSD.org>, Gergely Czuczy <gergely.czuczy@harmless.hu>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: process killed: text file modification Message-ID: <20170317141917.GS16105@kib.kiev.ua> In-Reply-To: <YTXPR01MB0189F7147A7C5C5F8C56B2F1DD390@YTXPR01MB0189.CANPRD01.PROD.OUTLOOK.COM> References: <45436522-77df-f894-0569-737a6a74958f@harmless.hu> <55189643.aaZPuY77s8@ralph.baldwin.cx> <3ed3e4a3-23af-7267-39f1-9090093c9c1e@harmless.hu> <5ac94b9a-7ced-9eff-d746-7dddaaeca516@harmless.hu> <1489340839.40576.82.camel@freebsd.org> <FF55DB37-4A6B-4D88-B201-B3BCA1A11E87@FreeBSD.org> <YTXPR01MB01898D49933A82170FCAB7A0DD390@YTXPR01MB0189.CANPRD01.PROD.OUTLOOK.COM> <YTXPR01MB018944EF4248402AD421D825DD390@YTXPR01MB0189.CANPRD01.PROD.OUTLOOK.COM> <20170317083605.GQ16105@kib.kiev.ua> <YTXPR01MB0189F7147A7C5C5F8C56B2F1DD390@YTXPR01MB0189.CANPRD01.PROD.OUTLOOK.COM>
next in thread | previous in thread | raw e-mail | index | archive | help
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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20170317141917.GS16105>