Date: Sat, 3 Apr 2010 08:53:53 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r206130 - head/sys/geom Message-ID: <201004030853.o338rrYB036111@svn.freebsd.org>
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Author: avg Date: Sat Apr 3 08:53:53 2010 New Revision: 206130 URL: http://svn.freebsd.org/changeset/base/206130 Log: g_vfs_open: allow only one mount per device vnode In other words, deny multiple read-only mounts of the same device. Shared read-only mounts should theoretically be possible, but, unfortunately, can not be implemented correctly using current buffer cache code/interface and results in an eventual system crash. Also, using nullfs seems to be a more efficient way to achieve the same goal. This gets us back to where we were before GEOM and where other BSDs are. Submitted by: pjd (idea for checking for shared mounting) Discussed with: phk, pjd Silence from: fs@, geom@ MFC after: 2 weeks Modified: head/sys/geom/geom_vfs.c Modified: head/sys/geom/geom_vfs.c ============================================================================== --- head/sys/geom/geom_vfs.c Sat Apr 3 08:39:00 2010 (r206129) +++ head/sys/geom/geom_vfs.c Sat Apr 3 08:53:53 2010 (r206130) @@ -161,6 +161,10 @@ g_vfs_open(struct vnode *vp, struct g_co g_topology_assert(); *cpp = NULL; + bo = &vp->v_bufobj; + if (bo->bo_private != vp) + return (EBUSY); + pp = g_dev_getprovider(vp->v_rdev); if (pp == NULL) return (ENOENT); @@ -176,7 +180,7 @@ g_vfs_open(struct vnode *vp, struct g_co vnode_create_vobject(vp, pp->mediasize, curthread); VFS_UNLOCK_GIANT(vfslocked); *cpp = cp; - bo = &vp->v_bufobj; + cp->private = vp; bo->bo_ops = g_vfs_bufops; bo->bo_private = cp; bo->bo_bsize = pp->sectorsize; @@ -196,5 +200,6 @@ g_vfs_close(struct g_consumer *cp) gp = cp->geom; bo = gp->softc; bufobj_invalbuf(bo, V_SAVE, 0, 0); + bo->bo_private = cp->private; g_wither_geom_close(gp, ENXIO); }
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