Date: Fri, 17 Mar 2017 20:47:53 +0100 From: Dimitry Andric <dim@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Rick Macklem <rmacklem@uoguelph.ca>, 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: <D0770019-3EEA-45D2-A751-18DF1B274F90@FreeBSD.org> In-Reply-To: <20170317141917.GS16105@kib.kiev.ua> 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> <20170317141917.GS16105@kib.kiev.ua>
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[-- Attachment #1 --] On 17 Mar 2017, at 15:19, Konstantin Belousov <kostikbel@gmail.com> wrote: > > 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 FWIW, Rick's patch seems to do the trick, both for my test case and lld itself. And even with vfs.timestamp_precision=3 on both server and client. -Dimitry [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.30 iEYEARECAAYFAljMPXEACgkQsF6jCi4glqOi3wCfRpH+RjEYSVN4InJXsFdyUdZc v2wAn3AD55eetKriKKscKDN1g527zobq =LD1C -----END PGP SIGNATURE-----
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