/* $OpenBSD: union_vnops.c,v 1.13 2001/06/23 02:14:26 csapuntz Exp $ */ /* $NetBSD: union_vnops.c,v 1.30.4.1 1996/05/25 22:10:14 jtc Exp $ */ /* * Copyright (c) 1992, 1993, 1994 The Regents of the University of California. * Copyright (c) 1992, 1993, 1994 Jan-Simon Pendry. * All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)union_vnops.c 8.22 (Berkeley) 12/10/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Global vfs data structures */ int union_lookup __P((void *)); int union_create __P((void *)); int union_whiteout __P((void *)); int union_mknod __P((void *)); int union_open __P((void *)); int union_close __P((void *)); int union_access __P((void *)); int union_getattr __P((void *)); int union_setattr __P((void *)); int union_read __P((void *)); int union_write __P((void *)); int union_lease __P((void *)); int union_ioctl __P((void *)); int union_select __P((void *)); int union_fsync __P((void *)); int union_remove __P((void *)); int union_link __P((void *)); int union_rename __P((void *)); int union_mkdir __P((void *)); int union_rmdir __P((void *)); int union_revoke __P((void *)); int union_symlink __P((void *)); int union_readdir __P((void *)); int union_readlink __P((void *)); int union_abortop __P((void *)); int union_inactive __P((void *)); int union_reclaim __P((void *)); int union_lock __P((void *)); int union_unlock __P((void *)); int union_bmap __P((void *)); int union_print __P((void *)); int union_islocked __P((void *)); int union_pathconf __P((void *)); int union_advlock __P((void *)); int union_strategy __P((void *)); int (**union_vnodeop_p) __P((void *)); struct vnodeopv_entry_desc union_vnodeop_entries[] = { { &vop_default_desc, vn_default_error }, { &vop_lookup_desc, union_lookup }, /* lookup */ { &vop_create_desc, union_create }, /* create */ { &vop_whiteout_desc, union_whiteout }, /* whiteout */ { &vop_mknod_desc, union_mknod }, /* mknod */ { &vop_open_desc, union_open }, /* open */ { &vop_close_desc, union_close }, /* close */ { &vop_access_desc, union_access }, /* access */ { &vop_getattr_desc, union_getattr }, /* getattr */ { &vop_setattr_desc, union_setattr }, /* setattr */ { &vop_read_desc, union_read }, /* read */ { &vop_write_desc, union_write }, /* write */ { &vop_lease_desc, union_lease }, /* lease */ { &vop_ioctl_desc, union_ioctl }, /* ioctl */ { &vop_select_desc, union_select }, /* select */ { &vop_fsync_desc, union_fsync }, /* fsync */ { &vop_remove_desc, union_remove }, /* remove */ { &vop_link_desc, union_link }, /* link */ { &vop_rename_desc, union_rename }, /* rename */ { &vop_mkdir_desc, union_mkdir }, /* mkdir */ { &vop_rmdir_desc, union_rmdir }, /* rmdir */ { &vop_symlink_desc, union_symlink }, /* symlink */ { &vop_readdir_desc, union_readdir }, /* readdir */ { &vop_readlink_desc, union_readlink }, /* readlink */ { &vop_revoke_desc, union_revoke }, /* revoke */ { &vop_abortop_desc, union_abortop }, /* abortop */ { &vop_inactive_desc, union_inactive }, /* inactive */ { &vop_reclaim_desc, union_reclaim }, /* reclaim */ { &vop_lock_desc, union_lock }, /* lock */ { &vop_unlock_desc, union_unlock }, /* unlock */ { &vop_bmap_desc, union_bmap }, /* bmap */ { &vop_strategy_desc, union_strategy }, /* strategy */ { &vop_print_desc, union_print }, /* print */ { &vop_islocked_desc, union_islocked }, /* islocked */ { &vop_pathconf_desc, union_pathconf }, /* pathconf */ { &vop_advlock_desc, union_advlock }, /* advlock */ { (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL } }; struct vnodeopv_desc union_vnodeop_opv_desc = { &union_vnodeop_p, union_vnodeop_entries }; #define FIXUP(un, p) { \ if (((un)->un_flags & UN_ULOCK) == 0) { \ union_fixup(un, p); \ } \ } static void union_fixup __P((struct union_node *, struct proc *)); static int union_lookup1 __P((struct vnode *, struct vnode **, struct vnode **, struct componentname *)); static void union_fixup(un, p) struct union_node *un; struct proc *p; { vn_lock(un->un_uppervp, LK_EXCLUSIVE | LK_RETRY, p); un->un_flags |= UN_ULOCK; } static int union_lookup1(udvp, dvpp, vpp, cnp) struct vnode *udvp; struct vnode **dvpp; struct vnode **vpp; struct componentname *cnp; { struct proc *p = cnp->cn_proc; int error; struct vnode *tdvp; struct vnode *dvp; struct mount *mp; dvp = *dvpp; /* * If stepping up the directory tree, check for going * back across the mount point, in which case do what * lookup would do by stepping back down the mount * hierarchy. */ if (cnp->cn_flags & ISDOTDOT) { while ((dvp != udvp) && (dvp->v_flag & VROOT)) { /* * Don't do the NOCROSSMOUNT check * at this level. By definition, * union fs deals with namespaces, not * filesystems. */ tdvp = dvp; *dvpp = dvp = dvp->v_mount->mnt_vnodecovered; vput(tdvp); VREF(dvp); vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); } } error = VOP_LOOKUP(dvp, &tdvp, cnp); if (error) return (error); /* * The parent directory will have been unlocked, unless lookup * found the last component. In which case, re-lock the node * here to allow it to be unlocked again (phew) in union_lookup. */ if (dvp != tdvp && !(cnp->cn_flags & ISLASTCN)) vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); dvp = tdvp; /* * Lastly check if the current node is a mount point in * which case walk up the mount hierarchy making sure not to * bump into the root of the mount tree (ie. dvp != udvp). */ while (dvp != udvp && (dvp->v_type == VDIR) && (mp = dvp->v_mountedhere)) { if (vfs_busy(mp, 0, 0, p)) continue; error = VFS_ROOT(mp, &tdvp); vfs_unbusy(mp, p); vput(dvp); if (error) { return (error); } dvp = tdvp; } *vpp = dvp; return (0); } int union_lookup(v) void *v; { struct vop_lookup_args /* { struct vnodeop_desc *a_desc; struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; } */ *ap = v; int error; int uerror, lerror; struct vnode *uppervp, *lowervp; struct vnode *upperdvp, *lowerdvp; struct vnode *dvp = ap->a_dvp; struct union_node *dun = VTOUNION(dvp); struct proc *p = curproc; struct componentname *cnp = ap->a_cnp; int lockparent = cnp->cn_flags & LOCKPARENT; struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); struct ucred *saved_cred = NULL; int iswhiteout; struct vattr va; #ifdef notyet if (cnp->cn_namelen == 3 && cnp->cn_nameptr[2] == '.' && cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') { dvp = *ap->a_vpp = LOWERVP(ap->a_dvp); if (dvp == NULLVP) return (ENOENT); VREF(dvp); vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); if (!lockparent || !(cnp->cn_flags & ISLASTCN)) VOP_UNLOCK(ap->a_dvp, 0, p, 0, p); return (0); } #endif cnp->cn_flags |= LOCKPARENT; upperdvp = dun->un_uppervp; lowerdvp = dun->un_lowervp; uppervp = NULLVP; lowervp = NULLVP; iswhiteout = 0; /* * do the lookup in the upper level. * if that level comsumes additional pathnames, * then assume that something special is going * on and just return that vnode. */ if (upperdvp != NULLVP) { FIXUP(dun, p); /* * If we're doing `..' in the underlying filesystem, * we must drop our lock on the union node before * going up the tree in the lower file system--if we block * on the lowervp lock, and that's held by someone else * coming down the tree and who's waiting for our lock, * we would be hosed. */ if (cnp->cn_flags & ISDOTDOT) { /* retain lock on underlying VP: */ dun->un_flags |= UN_KLOCK; VOP_UNLOCK(dvp, 0, p); } uerror = union_lookup1(um->um_uppervp, &upperdvp, &uppervp, cnp); if (cnp->cn_flags & ISDOTDOT) { if (dun->un_uppervp == upperdvp) { /* * we got the underlying bugger back locked... * now take back the union node lock. Since we * hold the uppervp lock, we can diddle union * locking flags at will. :) */ dun->un_flags |= UN_ULOCK; } /* * if upperdvp got swapped out, it means we did * some mount point magic, and we do not have * dun->un_uppervp locked currently--so we get it * locked here (don't set the UN_ULOCK flag). */ vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); } /*if (uppervp == upperdvp) dun->un_flags |= UN_KLOCK;*/ if (cnp->cn_consume != 0) { *ap->a_vpp = uppervp; if (!lockparent) cnp->cn_flags &= ~LOCKPARENT; return (uerror); } if (uerror == ENOENT || uerror == EJUSTRETURN) { if (cnp->cn_flags & ISWHITEOUT) { iswhiteout = 1; } else if (lowerdvp != NULLVP) { lerror = VOP_GETATTR(upperdvp, &va, cnp->cn_cred, cnp->cn_proc); if (lerror == 0 && (va.va_flags & OPAQUE)) iswhiteout = 1; } } } else { uerror = ENOENT; } /* * in a similar way to the upper layer, do the lookup * in the lower layer. this time, if there is some * component magic going on, then vput whatever we got * back from the upper layer and return the lower vnode * instead. */ if (lowerdvp != NULLVP && !iswhiteout) { int nameiop; vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY, p); /* * Only do a LOOKUP on the bottom node, since * we won't be making changes to it anyway. */ nameiop = cnp->cn_nameiop; cnp->cn_nameiop = LOOKUP; if (um->um_op == UNMNT_BELOW) { saved_cred = cnp->cn_cred; cnp->cn_cred = um->um_cred; } /* * we shouldn't have to worry about locking interactions * between the lower layer and our union layer (w.r.t. * `..' processing) because we don't futz with lowervp * locks in the union-node instantiation code path. */ lerror = union_lookup1(um->um_lowervp, &lowerdvp, &lowervp, cnp); if (um->um_op == UNMNT_BELOW) cnp->cn_cred = saved_cred; cnp->cn_nameiop = nameiop; if (lowervp != lowerdvp) VOP_UNLOCK(lowerdvp, 0, p); if (cnp->cn_consume != 0) { if (uppervp != NULLVP) { if (uppervp == upperdvp) vrele(uppervp); else vput(uppervp); uppervp = NULLVP; } *ap->a_vpp = lowervp; if (!lockparent) cnp->cn_flags &= ~LOCKPARENT; return (lerror); } } else { lerror = ENOENT; if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { lowervp = LOWERVP(dun->un_pvp); if (lowervp != NULLVP) { VREF(lowervp); vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY, p); lerror = 0; } } } if (!lockparent) cnp->cn_flags &= ~LOCKPARENT; /* * at this point, we have uerror and lerror indicating * possible errors with the lookups in the upper and lower * layers. additionally, uppervp and lowervp are (locked) * references to existing vnodes in the upper and lower layers. * * there are now three cases to consider. * 1. if both layers returned an error, then return whatever * error the upper layer generated. * * 2. if the top layer failed and the bottom layer succeeded * then two subcases occur. * a. the bottom vnode is not a directory, in which * case just return a new union vnode referencing * an empty top layer and the existing bottom layer. * b. the bottom vnode is a directory, in which case * create a new directory in the top-level and * continue as in case 3. * * 3. if the top layer succeeded then return a new union * vnode referencing whatever the new top layer and * whatever the bottom layer returned. */ *ap->a_vpp = NULLVP; /* case 1. */ if ((uerror != 0) && (lerror != 0)) { return (uerror); } /* case 2. */ if (uerror != 0 /* && (lerror == 0) */ ) { if (lowervp->v_type == VDIR) { /* case 2b. */ /* * We may be racing another process to make the * upper-level shadow directory. Be careful with * locks/etc! */ dun->un_flags &= ~UN_ULOCK; VOP_UNLOCK(upperdvp, 0, p); uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY, p); dun->un_flags |= UN_ULOCK; if (uerror) { if (lowervp != NULLVP) { vput(lowervp); lowervp = NULLVP; } return (uerror); } } } if (lowervp != NULLVP) VOP_UNLOCK(lowervp, 0, p); error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, uppervp, lowervp, 1); if (error) { if (uppervp != NULLVP) vput(uppervp); if (lowervp != NULLVP) vrele(lowervp); } else { if (*ap->a_vpp != dvp) if (!lockparent || !(cnp->cn_flags & ISLASTCN)) VOP_UNLOCK(dvp, 0, p); if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.' && *ap->a_vpp != dvp) { panic("union_lookup returning. (%x) not same as startdir (%x)", ap->a_vpp, dvp); } } return (error); } int union_create(v) void *v; { struct vop_create_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp; struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; if ((dvp = un->un_uppervp) != NULLVP) { int error; struct vnode *vp; struct mount *mp; FIXUP(un, p); VREF(dvp); un->un_flags |= UN_KLOCK; mp = ap->a_dvp->v_mount; vput(ap->a_dvp); error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); if (error) return (error); error = union_allocvp( ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp, NULLVP, 1); if (error) vput(vp); return (error); } vput(ap->a_dvp); return (EROFS); } int union_whiteout(v) void *v; { struct vop_whiteout_args /* { struct vnode *a_dvp; struct componentname *a_cnp; int a_flags; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_dvp); struct proc *p = curproc; if (un->un_uppervp == NULLVP) return (EOPNOTSUPP); FIXUP(un, p); return (VOP_WHITEOUT(un->un_uppervp, ap->a_cnp, ap->a_flags)); } int union_mknod(v) void *v; { struct vop_mknod_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp; struct proc *p = ap->a_cnp->cn_proc; if ((dvp = un->un_uppervp) != NULLVP) { int error; struct vnode *vp; struct mount *mp; FIXUP(un, p); VREF(dvp); un->un_flags |= UN_KLOCK; mp = ap->a_dvp->v_mount; vput(ap->a_dvp); error = VOP_MKNOD(dvp, &vp, ap->a_cnp, ap->a_vap); if (error) return (error); if (vp != NULLVP) { error = union_allocvp( ap->a_vpp, mp, NULLVP, NULLVP, ap->a_cnp, vp, NULLVP, 1); if (error) vput(vp); } return (error); } vput(ap->a_dvp); return (EROFS); } int union_open(v) void *v; { struct vop_open_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; int a_mode; struct ucred *a_cred; struct proc *a_p; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *tvp; int mode = ap->a_mode; struct ucred *cred = ap->a_cred; struct proc *p = ap->a_p; int error; /* * If there is an existing upper vp then simply open that. */ tvp = un->un_uppervp; if (tvp == NULLVP) { /* * If the lower vnode is being opened for writing, then * copy the file contents to the upper vnode and open that, * otherwise can simply open the lower vnode. */ tvp = un->un_lowervp; if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { error = union_copyup(un, (mode&O_TRUNC) == 0, cred, p); if (error == 0) error = VOP_OPEN(un->un_uppervp, mode, cred, p); return (error); } /* * Just open the lower vnode */ un->un_openl++; vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, p); error = VOP_OPEN(tvp, mode, cred, p); VOP_UNLOCK(tvp, 0, p); return (error); } FIXUP(un, p); error = VOP_OPEN(tvp, mode, cred, p); return (error); } int union_close(v) void *v; { struct vop_close_args /* { struct vnode *a_vp; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp; if ((vp = un->un_uppervp) == NULLVP) { #ifdef UNION_DIAGNOSTIC if (un->un_openl <= 0) panic("union: un_openl cnt"); #endif --un->un_openl; vp = un->un_lowervp; } #ifdef UNION_DIAGNOSTIC /* * A stranded union node may end up here with both vnodes NULL, * in which case we don't do anything. */ if (vp == NULLVP) { vprint("empty union vnode", vp); panic("union_close empty vnode"); } #endif ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_close), ap)); } /* * Check access permission on the union vnode. * The access check being enforced is to check * against both the underlying vnode, and any * copied vnode. This ensures that no additional * file permissions are given away simply because * the user caused an implicit file copy. */ int union_access(v) void *v; { struct vop_access_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; int a_mode; struct ucred *a_cred; struct proc *a_p; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); int error = EACCES; struct vnode *vp; struct proc *p = ap->a_p; if ((vp = un->un_uppervp) != NULLVP) { FIXUP(un, p); return (VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p)); } if ((vp = un->un_lowervp) != NULLVP) { vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); error = VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p); if (error == 0) { struct union_mount *um = MOUNTTOUNIONMOUNT(ap->a_vp->v_mount); if (um->um_op == UNMNT_BELOW) error = VOP_ACCESS(vp, ap->a_mode, um->um_cred, ap->a_p); } VOP_UNLOCK(vp, 0, p); if (error) return (error); } return (error); } /* * We handle getattr only to change the fsid and * track object sizes */ int union_getattr(v) void *v; { struct vop_getattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *ap = v; int error; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp = un->un_uppervp; struct vattr *vap; struct vattr va; struct proc *p = ap->a_p; /* * Some programs walk the filesystem hierarchy by counting * links to directories to avoid stat'ing all the time. * This means the link count on directories needs to be "correct". * The only way to do that is to call getattr on both layers * and fix up the link count. The link count will not necessarily * be accurate but will be large enough to defeat the tree walkers. */ vap = ap->a_vap; if ((vp = un->un_uppervp) != NULLVP) { /* * It's not clear whether VOP_GETATTR is to be * called with the vnode locked or not. stat() calls * it with (vp) locked, and fstat calls it with * (vp) unlocked. * In the mean time, compensate here by checking * the union_node's lock flag. */ if (un->un_flags & UN_LOCKED) FIXUP(un, p); error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); if (error) return (error); union_newsize(ap->a_vp, vap->va_size, VNOVAL); } if (vp == NULLVP) { vp = un->un_lowervp; } else if (vp->v_type == VDIR) { vp = un->un_lowervp; vap = &va; } else { vp = NULLVP; } if (vp != NULLVP) { error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); if (error) return (error); union_newsize(ap->a_vp, VNOVAL, vap->va_size); } if ((vap != ap->a_vap) && (vap->va_type == VDIR)) ap->a_vap->va_nlink += vap->va_nlink; ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0]; return (0); } int union_setattr(v) void *v; { struct vop_setattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_p; int error; /* * Handle case of truncating lower object to zero size, * by creating a zero length upper object. This is to * handle the case of open with O_TRUNC and O_CREAT. */ if ((un->un_uppervp == NULLVP) && /* assert(un->un_lowervp != NULLVP) */ (un->un_lowervp->v_type == VREG)) { error = union_copyup(un, (ap->a_vap->va_size != 0), ap->a_cred, ap->a_p); if (error) return (error); } /* * Try to set attributes in upper layer, * otherwise return read-only filesystem error. */ if (un->un_uppervp != NULLVP) { FIXUP(un, p); error = VOP_SETATTR(un->un_uppervp, ap->a_vap, ap->a_cred, ap->a_p); if ((error == 0) && (ap->a_vap->va_size != VNOVAL)) union_newsize(ap->a_vp, ap->a_vap->va_size, VNOVAL); } else { error = EROFS; } return (error); } int union_read(v) void *v; { struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; struct ucred *a_cred; } */ *ap = v; int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); struct proc *p = curproc; if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); else FIXUP(VTOUNION(ap->a_vp), p); error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); if (dolock) VOP_UNLOCK(vp, 0, p); /* * XXX * perhaps the size of the underlying object has changed under * our feet. take advantage of the offset information present * in the uio structure. */ if (error == 0) { struct union_node *un = VTOUNION(ap->a_vp); off_t cur = ap->a_uio->uio_offset; if (vp == un->un_uppervp) { if (cur > un->un_uppersz) union_newsize(ap->a_vp, cur, VNOVAL); } else { if (cur > un->un_lowersz) union_newsize(ap->a_vp, VNOVAL, cur); } } return (error); } int union_write(v) void *v; { struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; struct ucred *a_cred; } */ *ap = v; int error; struct vnode *vp; struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = curproc; vp = UPPERVP(ap->a_vp); if (vp == NULLVP) panic("union: missing upper layer in write"); FIXUP(un, p); error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); /* * the size of the underlying object may be changed by the * write. */ if (error == 0) { off_t cur = ap->a_uio->uio_offset; if (cur > un->un_uppersz) union_newsize(ap->a_vp, cur, VNOVAL); } return (error); } int union_lease(v) void *v; { struct vop_lease_args /* { struct vnode *a_vp; struct proc *a_p; struct ucred *a_cred; int a_flag; } */ *ap = v; register struct vnode *vp = OTHERVP(ap->a_vp); ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_lease), ap)); } int union_ioctl(v) void *v; { struct vop_ioctl_args /* { struct vnode *a_vp; u_long a_command; caddr_t a_data; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *ap = v; register struct vnode *vp = OTHERVP(ap->a_vp); ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_ioctl), ap)); } int union_select(v) void *v; { struct vop_select_args /* { struct vnode *a_vp; int a_which; int a_fflags; struct ucred *a_cred; struct proc *a_p; } */ *ap = v; register struct vnode *vp = OTHERVP(ap->a_vp); ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_select), ap)); } int union_fsync(v) void *v; { struct vop_fsync_args /* { struct vnode *a_vp; struct ucred *a_cred; int a_waitfor; struct proc *a_p; } */ *ap = v; int error = 0; struct vnode *targetvp = OTHERVP(ap->a_vp); struct proc *p = ap->a_p; if (targetvp != NULLVP) { int dolock = (targetvp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY, p); else FIXUP(VTOUNION(ap->a_vp), p); error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, ap->a_p); if (dolock) VOP_UNLOCK(targetvp, 0, p); } return (error); } /* a_dvp: directory in which to link a_vp: new target of the link a_cnp: name for the link */ int union_remove(v) void *v; { struct vop_remove_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap = v; int error; struct union_node *dun = VTOUNION(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_cnp->cn_proc; if (dun->un_uppervp == NULLVP) panic("union remove: null upper vnode"); if (un->un_uppervp != NULLVP) { struct vnode *dvp = dun->un_uppervp; struct vnode *vp = un->un_uppervp; struct componentname *cnp = ap->a_cnp; FIXUP(dun, p); VREF(dvp); dun->un_flags |= UN_KLOCK; vput(ap->a_dvp); FIXUP(un, p); VREF(vp); un->un_flags |= UN_KLOCK; vput(ap->a_vp); if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc)) cnp->cn_flags |= DOWHITEOUT; error = VOP_REMOVE(dvp, vp, cnp); if (!error) union_removed_upper(un); } else { FIXUP(dun, p); error = union_mkwhiteout( MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), dun->un_uppervp, ap->a_cnp, un->un_path); vput(ap->a_dvp); vput(ap->a_vp); } return (error); } /* a_dvp: directory in which to link a_vp: new target of the link a_cnp: name for the link */ int union_link(v) void *v; { struct vop_link_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap = v; int error = 0; struct union_node *dun; struct vnode *dvp; struct vnode *vp; struct proc *p = ap->a_cnp->cn_proc; dun = VTOUNION(ap->a_dvp); #ifdef DIAGNOSTIC if (!(ap->a_cnp->cn_flags & LOCKPARENT)) { printf("union_link called without LOCKPARENT set!\n"); error = EIO; /* need some error code for "caller is a bozo" */ } else #endif if (ap->a_dvp->v_op != ap->a_vp->v_op) { vp = ap->a_vp; } else { struct union_node *un = VTOUNION(ap->a_vp); if (un->un_uppervp == NULLVP) { /* * needs to be copied up before we can link it. */ vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, p); if (dun->un_uppervp == un->un_dirvp) { VOP_UNLOCK(ap->a_dvp, 0, p); } error = union_copyup(un, 1, ap->a_cnp->cn_cred, ap->a_cnp->cn_proc); if (dun->un_uppervp == un->un_dirvp) { /* During copyup, we dropped the lock on the * dir and invalidated any saved namei lookup * state for the directory we'll be entering * the link in. We need to re-run the lookup * in that directory to reset any state needed * for VOP_LINK. * Call relookup on the union-layer to * reset the state. */ vp = NULLVP; if (dun->un_uppervp == NULLVP || /* * relookup starts with an unlocked node, * and since LOCKPARENT is set returns * the starting directory locked. */ (error = relookup(ap->a_dvp, &dvp, ap->a_cnp))) { vrele(ap->a_dvp); VOP_UNLOCK(ap->a_vp, 0, p); return EROFS; } if (dvp != NULLVP) { /* The name we want to create has mysteriously appeared (a race?) */ error = EEXIST; VOP_UNLOCK(ap->a_vp, 0, p); goto croak; } } VOP_UNLOCK(ap->a_vp, 0, p); } vp = un->un_uppervp; } dvp = dun->un_uppervp; if (dvp == NULLVP) error = EROFS; if (error) { croak: vput(ap->a_dvp); return (error); } FIXUP(dun, p); VREF(dvp); dun->un_flags |= UN_KLOCK; vput(ap->a_dvp); return (VOP_LINK(dvp, vp, ap->a_cnp)); } int union_rename(v) void *v; { struct vop_rename_args /* { struct vnode *a_fdvp; struct vnode *a_fvp; struct componentname *a_fcnp; struct vnode *a_tdvp; struct vnode *a_tvp; struct componentname *a_tcnp; } */ *ap = v; int error; struct vnode *fdvp = ap->a_fdvp; struct vnode *fvp = ap->a_fvp; struct vnode *tdvp = ap->a_tdvp; struct vnode *tvp = ap->a_tvp; struct union_node *unfile = (struct union_node *)0; if (fdvp->v_op == union_vnodeop_p) { /* always true */ struct union_node *un = VTOUNION(fdvp); if (un->un_uppervp == NULLVP) { /* * this should never happen in normal * operation but might if there was * a problem creating the top-level shadow * directory. */ error = EXDEV; goto bad; } fdvp = un->un_uppervp; VREF(fdvp); vrele(ap->a_fdvp); } if (fvp->v_op == union_vnodeop_p) { /* always true */ unfile = VTOUNION(fvp); if (unfile->un_uppervp == NULLVP) { /* XXX: should do a copyup */ error = EXDEV; goto bad; } if (unfile->un_lowervp != NULLVP) ap->a_fcnp->cn_flags |= DOWHITEOUT; fvp = unfile->un_uppervp; VREF(fvp); /* vrele(ap->a_fvp); */ /* hold for later */ } if (tdvp->v_op == union_vnodeop_p) { struct union_node *un = VTOUNION(tdvp); if (un->un_uppervp == NULLVP) { /* * this should never happen in normal * operation but might if there was * a problem creating the top-level shadow * directory. */ error = EXDEV; goto badrele; } tdvp = un->un_uppervp; VREF(tdvp); un->un_flags |= UN_KLOCK; vput(ap->a_tdvp); } if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { struct union_node *un = VTOUNION(tvp); tvp = un->un_uppervp; if (tvp != NULLVP) { VREF(tvp); un->un_flags |= UN_KLOCK; } #if 0 /* XXX should we toss from the cache? */ if (un->un_flags & UN_CACHED) { un->un_flags &= ~UN_CACHED; LIST_REMOVE(un, un_cache); } #endif vput(ap->a_tvp); } error = VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp); if (!error && unfile) union_removed_upper(unfile); vrele(ap->a_fvp); return error; badrele: vrele(ap->a_fvp); bad: vrele(fdvp); vrele(fvp); vput(tdvp); if (tvp != NULLVP) vput(tvp); return (error); } int union_mkdir(v) void *v; { struct vop_mkdir_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp = un->un_uppervp; struct proc *p = ap->a_cnp->cn_proc; if (dvp != NULLVP) { int error; struct vnode *vp; FIXUP(un, p); VREF(dvp); un->un_flags |= UN_KLOCK; VOP_UNLOCK(ap->a_dvp, 0, p); error = VOP_MKDIR(dvp, &vp, ap->a_cnp, ap->a_vap); if (error) { vrele(ap->a_dvp); return (error); } error = union_allocvp( ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, NULLVP, ap->a_cnp, vp, NULLVP, 1); vrele(ap->a_dvp); if (error) vput(vp); return (error); } vput(ap->a_dvp); return (EROFS); } int union_rmdir(v) void *v; { struct vop_rmdir_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap = v; int error; struct union_node *dun = VTOUNION(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_cnp->cn_proc; if (dun->un_uppervp == NULLVP) panic("union rmdir: null upper vnode"); if (un->un_uppervp != NULLVP) { struct vnode *dvp = dun->un_uppervp; struct vnode *vp = un->un_uppervp; struct componentname *cnp = ap->a_cnp; FIXUP(dun, p); VREF(dvp); dun->un_flags |= UN_KLOCK; vput(ap->a_dvp); FIXUP(un, p); VREF(vp); un->un_flags |= UN_KLOCK; vput(ap->a_vp); if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc)) cnp->cn_flags |= DOWHITEOUT; error = VOP_RMDIR(dvp, vp, cnp); if (!error) union_removed_upper(un); } else { FIXUP(dun, p); error = union_mkwhiteout( MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), dun->un_uppervp, ap->a_cnp, un->un_path); vput(ap->a_dvp); vput(ap->a_vp); } return (error); } int union_symlink(v) void *v; { struct vop_symlink_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; char *a_target; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp = un->un_uppervp; struct proc *p = ap->a_cnp->cn_proc; if (dvp != NULLVP) { int error; struct vnode *vp; FIXUP(un, p); VREF(dvp); un->un_flags |= UN_KLOCK; vput(ap->a_dvp); error = VOP_SYMLINK(dvp, &vp, ap->a_cnp, ap->a_vap, ap->a_target); *ap->a_vpp = NULLVP; return (error); } vput(ap->a_dvp); return (EROFS); } /* * union_readdir works in concert with getdirentries and * readdir(3) to provide a list of entries in the unioned * directories. getdirentries is responsible for walking * down the union stack. readdir(3) is responsible for * eliminating duplicate names from the returned data stream. */ int union_readdir(v) void *v; { struct vop_readdir_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; struct uio *a_uio; struct ucred *a_cred; int *a_eofflag; int *a_ncookies; u_long **a_cookies; } */ *ap = v; register struct union_node *un = VTOUNION(ap->a_vp); register struct vnode *vp; struct proc *p = curproc; if ((vp = un->un_uppervp) == NULLVP) return (0); FIXUP(un, p); ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_readdir), ap)); } int union_readlink(v) void *v; { struct vop_readlink_args /* { struct vnode *a_vp; struct uio *a_uio; struct ucred *a_cred; } */ *ap = v; int error; struct vnode *vp = OTHERVP(ap->a_vp); struct proc *p = curproc; int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); else FIXUP(VTOUNION(ap->a_vp), p); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_readlink), ap); if (dolock) VOP_UNLOCK(vp, 0, p); return (error); } /* * When operations want to vput() a union node yet retain a lock on * the upper VP (say, to do some further operations like link(), * mkdir(), ...), they set UN_KLOCK on the union node, then call * vput() which calls VOP_UNLOCK(, 0, p) and comes here. union_unlock() * unlocks the union node (leaving the upper VP alone), clears the * KLOCK flag, and then returns to vput(). The caller then does whatever * is left to do with the upper VP, and insures that it gets unlocked. * * If UN_KLOCK isn't set, then the upper VP is unlocked here. */ int union_abortop(v) void *v; { struct vop_abortop_args /* { struct vnode *a_dvp; struct componentname *a_cnp; } */ *ap = v; int error; struct vnode *vp = OTHERVP(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_dvp); struct proc *p = ap->a_cnp->cn_proc; int islocked = un->un_flags & UN_LOCKED; int dolock = (vp == LOWERVP(ap->a_dvp)); if (islocked) { if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); else FIXUP(VTOUNION(ap->a_dvp), p); } ap->a_dvp = vp; error = VCALL(vp, VOFFSET(vop_abortop), ap); if (islocked && dolock) VOP_UNLOCK(vp, 0, p); return (error); } int union_inactive(v) void *v; { struct vop_inactive_args /* { struct vnode *a_vp; struct proc *a_p; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); /* * Do nothing (and _don't_ bypass). * Wait to vrele lowervp until reclaim, * so that until then our union_node is in the * cache and reusable. * * NEEDSWORK: Someday, consider inactive'ing * the lowervp and then trying to reactivate it * with capabilities (v_id) * like they do in the name lookup cache code. * That's too much work for now. */ #ifdef UNION_DIAGNOSTIC if (un->un_flags & UN_LOCKED) panic("union: inactivating locked node"); if (un->un_flags & UN_ULOCK) panic("union: inactivating w/locked upper node"); #endif union_diruncache(un); VOP_UNLOCK(ap->a_vp, 0, ap->a_p); if ((un->un_flags & UN_CACHED) == 0) vrecycle(ap->a_vp, (struct simplelock *)0, ap->a_p); return (0); } int union_reclaim(v) void *v; { struct vop_reclaim_args /* { struct vnode *a_vp; } */ *ap = v; union_freevp(ap->a_vp); return (0); } int union_lock(v) void *v; { struct vop_lock_args *ap = v; struct vnode *vp = ap->a_vp; struct union_node *un; struct proc *p = ap->a_p; int flags = ap->a_flags; int error = 0; vop_generic_lock(ap); /* * Need to do real lockmgr-style locking here. * in the mean time, draining won't work quite right, * which could lead to a few race conditions. * the following test was here, but is not quite right, we * still need to take the lock: if ((flags & LK_TYPE_MASK) == LK_DRAIN) return (0); */ flags &= ~LK_INTERLOCK; start: un = VTOUNION(vp); if (un->un_uppervp != NULLVP) { if (((un->un_flags & UN_ULOCK) == 0) && (vp->v_usecount != 0)) { error = vn_lock(un->un_uppervp, flags, p); if (error) return (error); un->un_flags |= UN_ULOCK; } #ifdef DIAGNOSTIC if (un->un_flags & UN_KLOCK) { vprint("union: dangling klock", vp); panic("union: dangling upper lock (%lx)", vp); } #endif } if (un->un_flags & UN_LOCKED) { #ifdef DIAGNOSTIC if (curproc && un->un_pid == curproc->p_pid && un->un_pid > -1 && curproc->p_pid > -1) panic("union: locking against myself"); #endif un->un_flags |= UN_WANTED; sleep((caddr_t)un, PINOD); goto start; } #ifdef DIAGNOSTIC if (curproc) un->un_pid = curproc->p_pid; else un->un_pid = -1; #endif un->un_flags |= UN_LOCKED; return (0); } /* * When operations want to vput() a union node yet retain a lock on * the upper VP (say, to do some further operations like link(), * mkdir(), ...), they set UN_KLOCK on the union node, then call * vput() which calls VOP_UNLOCK(, 0, p) and comes here. union_unlock() * unlocks the union node (leaving the upper VP alone), clears the * KLOCK flag, and then returns to vput(). The caller then does whatever * is left to do with the upper VP, and insures that it gets unlocked. * * If UN_KLOCK isn't set, then the upper VP is unlocked here. */ int union_unlock(v) void *v; { struct vop_lock_args *ap = v; struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_p; #ifdef DIAGNOSTIC if ((un->un_flags & UN_LOCKED) == 0) panic("union: unlock unlocked node"); if (curproc && un->un_pid != curproc->p_pid && curproc->p_pid > -1 && un->un_pid > -1) panic("union: unlocking other process's union node"); #endif un->un_flags &= ~UN_LOCKED; if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK) VOP_UNLOCK(un->un_uppervp, 0, p); un->un_flags &= ~(UN_ULOCK|UN_KLOCK); if (un->un_flags & UN_WANTED) { un->un_flags &= ~UN_WANTED; wakeup((caddr_t)un); } #ifdef DIAGNOSTIC un->un_pid = 0; #endif vop_generic_unlock(v); return (0); } int union_bmap(v) void *v; { struct vop_bmap_args /* { struct vnode *a_vp; daddr_t a_bn; struct vnode **a_vpp; daddr_t *a_bnp; int *a_runp; } */ *ap = v; int error; struct proc *p = curproc; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); else FIXUP(VTOUNION(ap->a_vp), p); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_bmap), ap); if (dolock) VOP_UNLOCK(vp, 0, p); return (error); } int union_print(v) void *v; { struct vop_print_args /* { struct vnode *a_vp; } */ *ap = v; struct vnode *vp = ap->a_vp; printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n", vp, UPPERVP(vp), LOWERVP(vp)); if (UPPERVP(vp)) vprint("uppervp", UPPERVP(vp)); if (LOWERVP(vp)) vprint("lowervp", LOWERVP(vp)); if (VTOUNION(vp)->un_dircache) { struct vnode **vpp; for (vpp = VTOUNION(vp)->un_dircache; *vpp != NULLVP; vpp++) vprint("dircache:", *vpp); } return (0); } int union_islocked(v) void *v; { struct vop_islocked_args /* { struct vnode *a_vp; } */ *ap = v; return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0); } int union_pathconf(v) void *v; { struct vop_pathconf_args /* { struct vnode *a_vp; int a_name; register_t *a_retval; } */ *ap = v; int error; struct vnode *vp = OTHERVP(ap->a_vp); struct proc *p = curproc; int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); else FIXUP(VTOUNION(ap->a_vp), p); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_pathconf), ap); if (dolock) VOP_UNLOCK(vp, 0, p); return (error); } int union_revoke(v) void *v; { struct vop_revoke_args /* { struct vnode *a_vp; int a_flags; struct proc *a_p; } */ *ap = v; struct vnode *vp = ap->a_vp; if (UPPERVP(vp)) VOP_REVOKE(UPPERVP(vp), ap->a_flags); if (LOWERVP(vp)) VOP_REVOKE(LOWERVP(vp), ap->a_flags); vgone(vp); return (0); } int union_advlock(v) void *v; { struct vop_advlock_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; caddr_t a_id; int a_op; struct flock *a_fl; int a_flags; } */ *ap = v; register struct vnode *vp = OTHERVP(ap->a_vp); ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_advlock), ap)); } /* * XXX - vop_strategy must be hand coded because it has no * vnode in its arguments. * This goes away with a merged VM/buffer cache. */ int union_strategy(v) void *v; { struct vop_strategy_args /* { struct buf *a_bp; } */ *ap = v; struct buf *bp = ap->a_bp; int error; struct vnode *savedvp; savedvp = bp->b_vp; bp->b_vp = OTHERVP(bp->b_vp); #ifdef DIAGNOSTIC if (bp->b_vp == NULLVP) panic("union_strategy: nil vp"); if (((bp->b_flags & B_READ) == 0) && (bp->b_vp == LOWERVP(savedvp))) panic("union_strategy: writing to lowervp"); #endif error = VOP_STRATEGY(bp); bp->b_vp = savedvp; return (error); }