Date: Sat, 30 Nov 2013 15:22:33 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: Kirk McKusick <mckusick@mckusick.com>, FreeBSD FS <freebsd-fs@freebsd.org> Subject: Re: RFC: NFS client patch to reduce sychronous writes Message-ID: <20131130132233.GZ59496@kib.kiev.ua> In-Reply-To: <1355437347.22943634.1385682620696.JavaMail.root@uoguelph.ca> References: <20131128191851.GM59496@kib.kiev.ua> <1355437347.22943634.1385682620696.JavaMail.root@uoguelph.ca>
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--4oAqxJayxW1dikgl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Nov 28, 2013 at 06:50:20PM -0500, Rick Macklem wrote: > obcount =3D np->n_size - (lbn * biosize); > *** This sets obcount to the byte offset within the buffer cache block of > EOF before it is grown by this write (or file size mod biosize, if yo= u prefer) > bp =3D nfs_getcacheblk(vp, lbn, obcount, td); >=20 > if (bp !=3D NULL) { > long save; >=20 > mtx_lock(&np->n_mtx); > np->n_size =3D uio->uio_offset + n; > np->n_flag |=3D NMODIFIED; > vnode_pager_setsize(vp, np->n_size); > *** n_size is now grown to the new EOF for after the write. > mtx_unlock(&np->n_mtx); >=20 > save =3D bp->b_flags & B_CACHE; > bcount =3D on + n; > allocbuf(bp, bcount); > bp->b_flags |=3D save; > if (noncontig_write !=3D 0 && bcount > obcount) > vfs_bio_bzero_buf(bp, obcount, bcount - > obcount); > *** This zeros bytes from "obcount" (the offset of the old EOF) to "bcoun= t" > (which is the offset of EOF after the write). I believe that I got it now, the patch in the other message looks fine. Thank you for the patience. --4oAqxJayxW1dikgl Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iQIcBAEBAgAGBQJSmeaYAAoJEJDCuSvBvK1BpGIP/1n2j1K6vE0EWb+xDJR0dJVa cr1yrpgYUjwrPLdoCzU8zyERahaIFd4i97jD6JFF2qksKNJyGBNAdfoei5IktIZf OHKXR8LKpMW5vBxNtMZpwy/UMR7sgFsAVna9NJ9GEYPJT1QMPOGG3mi4YO4nkuiu t2ZAMQCrwdQl/e9ehniot1WduSxb1kzcMUrJ3rPJME1GFLHsvEfY14udGvwxS44S fDPXNTmcYdS2IfDnGO+KB85eKFqclBjQxI+pIFQg6yss5ojFaQQvCdZ/+MeFpuVW GwGogqgoZ/QAfw0gBw9eOUPYJh7HIAraF6vDwq+fksKPLdTLevWzwWVEfhijfXRa 00206vE023Y4j5xZwSUcvK39sJMBSvdOoRojCnCSS0/2WCrVKbA0vLnKLVpA5lOP jUbp3vNSKQJFUyUi0GKzWJJ1Hr4KL423SymIKQdW4+IuvAr0iJoMhTj9qgi02fuQ 4V3PPJhuvEQiJVdM3alrhL+S0pObwSiVc4U2mTAS4g+3POJmy+pwv6gVO2fdCKI9 9lS1JAcrkYWAof3q7DtlhriXkdHf3DtjHVel1H25Wo3iYCntcFcqbnKibOpAHZKt Qg+lT/iZJ24pJpYUlVHEIvae8aWFXhOiMH1sVlZ5fdjJ1hm3CgIBu69lBQyKAmLH +tQtN4LEF7fM144gkok3 =QkIU -----END PGP SIGNATURE----- --4oAqxJayxW1dikgl--
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