Date: Wed, 22 Mar 2006 11:10:10 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Mikhail Teterin <mi+mx@aldan.algebra.com> Cc: alc@freebsd.org, stable@freebsd.org Subject: Re: more weird bugs with mmap-ing via NFS Message-ID: <20060322091010.GA20929@deviant.kiev.zoral.com.ua> In-Reply-To: <200603212107.48601.mi%2Bmx@aldan.algebra.com> References: <200603211607.30372.mi%2Bmx@aldan.algebra.com> <200603212045.39845.mi%2Bmx@aldan.algebra.com> <200603220153.k2M1rouk007739@apollo.backplane.com> <200603212107.48601.mi%2Bmx@aldan.algebra.com>
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--gKMricLos+KVdGMg Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 21, 2006 at 09:07:48PM -0500, Mikhail Teterin wrote: > =D7?=D7=D4=CF=D2=CF=CB 21 =C2=C5=D2=C5=DA=C5=CE=D8 2006 20:53, Matthew Di= llon =F7=C9 =CE=C1=D0=C9=D3=C1=CC=C9: > > Ah ha. That's the problem. I don't know why you are getting a wri= te > > error, but that is preventing the client from cleaning out the dirty > > buffers. The number of dirty buffers continues to rise and the clie= nt > > is just cycling on them over and over trying to write them out, > > because it's just as confused about why it is getting a permission > > denied error as you are >=20 > Well, whatever it is, this means a big juicy bug, does not it? I mean, th= e=20 > client should not get "confused" like this _ever_, but _especially_, when= it=20 > is talking to a fellow FreeBSD NFS-server. AFAIU, this is the design issue with unix buffer cache. System does assume that it can free dirty buffer (by writing it to the storage). See my later answer on the "nfsaio" problem, where the similar issues arise. Machine completely wedges if flushing of the dirty buffers stalls. I would be happy to be pointed out that my opinion is wrong, but fixing that problem would require big amount of reachitecturing the system. --gKMricLos+KVdGMg Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (FreeBSD) iD8DBQFEIRRwC3+MBN1Mb4gRAuo6AJ0T/BG2/LeVuEXwWmo52CvrTEgxiwCg0Tyb LCTsBKkUPxJnnB4LsK7IZAc= =A9HS -----END PGP SIGNATURE----- --gKMricLos+KVdGMg--
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