Date: Sun, 17 Oct 2010 16:30:33 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r213983 - head/share/man/man9 Message-ID: <201010171630.o9HGUXH9037941@svn.freebsd.org>
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Author: kib Date: Sun Oct 17 16:30:33 2010 New Revision: 213983 URL: http://svn.freebsd.org/changeset/base/213983 Log: Document vunref(9), add some important notes for vrele(9) and vput(9). Merge all three manpages to one, removing separate file for vput(9). MFC after: 1 week Deleted: head/share/man/man9/vput.9 Modified: head/share/man/man9/Makefile head/share/man/man9/vrele.9 Modified: head/share/man/man9/Makefile ============================================================================== --- head/share/man/man9/Makefile Sun Oct 17 15:55:46 2010 (r213982) +++ head/share/man/man9/Makefile Sun Oct 17 16:30:33 2010 (r213983) @@ -364,7 +364,6 @@ MAN= accept_filter.9 \ VOP_STRATEGY.9 \ VOP_VPTOCNP.9 \ VOP_VPTOFH.9 \ - vput.9 \ vref.9 \ vrefcnt.9 \ vrele.9 \ @@ -1366,6 +1365,8 @@ MLINKS+=VOP_RDWR.9 VOP_READ.9 \ VOP_RDWR.9 VOP_WRITE.9 MLINKS+=VOP_REMOVE.9 VOP_RMDIR.9 MLINKS+=vref.9 VREF.9 +MLINKS+=vrele.9 vput.9 \ + vrele.9 vunref.9 MLINKS+=vslock.9 vsunlock.9 MLINKS+=zero_copy.9 zero_copy_sockets.9 MLINKS+=zone.9 uma.9 \ Modified: head/share/man/man9/vrele.9 ============================================================================== --- head/share/man/man9/vrele.9 Sun Oct 17 15:55:46 2010 (r213982) +++ head/share/man/man9/vrele.9 Sun Oct 17 16:30:33 2010 (r213983) @@ -1,6 +1,7 @@ .\" -*- nroff -*- .\" .\" Copyright (c) 1996 Doug Rabson +.\" Copyright (c) 2010 Konstantin Belousov <kib@FreeBSD.org> .\" .\" All rights reserved. .\" @@ -28,17 +29,23 @@ .\" .\" $FreeBSD$ .\" -.Dd July 24, 1996 +.Dd October 17, 2010 .Dt VRELE 9 .Os .Sh NAME -.Nm vrele +.Nm vput , +.Nm vrele , +.Nm vunref .Nd decrement the use count for a vnode .Sh SYNOPSIS .In sys/param.h .In sys/vnode.h .Ft void +.Fn vput "struct vnode *vp" +.Ft void .Fn vrele "struct vnode *vp" +.Ft void +.Fn vunref "struct vnode *vp" .Sh DESCRIPTION Decrement the .Va v_usecount @@ -48,18 +55,51 @@ field of a vnode. the vnode to decrement .El .Pp -Any code in the system which is using a vnode should call +The .Fn vrele -when it is finished with the vnode. +function takes an unlocked vnode and returns with the vnode unlocked. +.Pp +.The +.Fn vput +function should be given a locked vnode as argument, the vnode is unlocked +after the function returned. +The +.Fn vput +is operationally equivalent to calling +.Xr VOP_UNLOCK 9 +followed by +.Xr vrele 9 , +with less overhead. +.Pp +The +.Fn vunref +function takes a locked vnode as argument, and returns with the vnode locked. +Nonetheless, the +.Fn vunref +might drop the vnode lock during the operation, so caller should not expect +that non-doomed vnode is still non-doomed after the function returned. +.Pp +Any code in the system which signified its use of a vnode by usecount +should call one of the listed function to decrement use counter. If the .Va v_usecount -field of the vnode reaches zero, then it will be placed on the free list. +field of the non-doomed vnode reaches zero, then it will be inactivated +and placed on the free list. +Since the functions might need to call VOPs for the vnode, the +.Va Giant +mutex should be conditionally locked around the call. +.Pp +The hold count for the vnode is always greater or equal to the usecount. +Non-forced unmount fails when mount point owns a vnode that has non-zero +usecount, see +.Xr vflush 9 . .Sh SEE ALSO .Xr vget 9 , .Xr vnode 9 , -.Xr vput 9 , .Xr vref 9 , .Xr vrefcnt 9 .Sh AUTHORS This manual page was written by -.An Doug Rabson . +.An Doug Rabson +and +.An Konstantin Belousov .
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