From owner-svn-src-head@freebsd.org Mon May 25 04:56:41 2020 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D01762F3A2A; Mon, 25 May 2020 04:56:41 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49VlDn4qQtz4JG8; Mon, 25 May 2020 04:56:41 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 9C6D5C7FB; Mon, 25 May 2020 04:56:41 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 04P4uffu051923; Mon, 25 May 2020 04:56:41 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 04P4ufcs051922; Mon, 25 May 2020 04:56:41 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <202005250456.04P4ufcs051922@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Mon, 25 May 2020 04:56:41 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r361440 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 361440 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 May 2020 04:56:41 -0000 Author: mjg Date: Mon May 25 04:56:41 2020 New Revision: 361440 URL: https://svnweb.freebsd.org/changeset/base/361440 Log: vfs: restore mtx-protected foffset locking for 32 bit platforms They depend on it to accurately read the offset. The new code is not used as it would add an interrupt enable/disable trip on top of the atomic. This also fixes a bug where 32-bit nolock request would still lock the offset. No changes for 64-bit. Reported by: emaste Modified: head/sys/kern/vfs_vnops.c Modified: head/sys/kern/vfs_vnops.c ============================================================================== --- head/sys/kern/vfs_vnops.c Mon May 25 04:17:01 2020 (r361439) +++ head/sys/kern/vfs_vnops.c Mon May 25 04:56:41 2020 (r361440) @@ -672,6 +672,7 @@ vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, voi return (error); } +#if OFF_MAX <= LONG_MAX off_t foffset_lock(struct file *fp, int flags) { @@ -681,14 +682,12 @@ foffset_lock(struct file *fp, int flags) KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); -#if OFF_MAX <= LONG_MAX /* * Caller only wants the current f_offset value. Assume that * the long and shorter integer types reads are atomic. */ if ((flags & FOF_NOLOCK) != 0) return (fp->f_offset); -#endif /* * According to McKusick the vn lock was protecting f_offset here. @@ -737,10 +736,8 @@ foffset_unlock(struct file *fp, off_t val, int flags) if ((flags & FOF_NEXTOFF) != 0) fp->f_nextoff = val; -#if OFF_MAX <= LONG_MAX if ((flags & FOF_NOLOCK) != 0) return; -#endif flagsp = &fp->f_vnread_flags; state = atomic_load_16(flagsp); @@ -755,6 +752,53 @@ foffset_unlock(struct file *fp, off_t val, int flags) sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); sleepq_release(&fp->f_vnread_flags); } +#else +off_t +foffset_lock(struct file *fp, int flags) +{ + struct mtx *mtxp; + off_t res; + + KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); + + mtxp = mtx_pool_find(mtxpool_sleep, fp); + mtx_lock(mtxp); + if ((flags & FOF_NOLOCK) == 0) { + while (fp->f_vnread_flags & FOFFSET_LOCKED) { + fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; + msleep(&fp->f_vnread_flags, mtxp, PUSER -1, + "vofflock", 0); + } + fp->f_vnread_flags |= FOFFSET_LOCKED; + } + res = fp->f_offset; + mtx_unlock(mtxp); + return (res); +} + +void +foffset_unlock(struct file *fp, off_t val, int flags) +{ + struct mtx *mtxp; + + KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); + + mtxp = mtx_pool_find(mtxpool_sleep, fp); + mtx_lock(mtxp); + if ((flags & FOF_NOUPDATE) == 0) + fp->f_offset = val; + if ((flags & FOF_NEXTOFF) != 0) + fp->f_nextoff = val; + if ((flags & FOF_NOLOCK) == 0) { + KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, + ("Lost FOFFSET_LOCKED")); + if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) + wakeup(&fp->f_vnread_flags); + fp->f_vnread_flags = 0; + } + mtx_unlock(mtxp); +} +#endif void foffset_lock_uio(struct file *fp, struct uio *uio, int flags)