/* $NetBSD: union_vnops.c,v 1.4 1994/06/29 06:35:26 cgd 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 8.15 (Berkeley) 6/4/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define FIXUP(un) { \ if (((un)->un_flags & UN_ULOCK) == 0) { \ union_fixup(un); \ } \ } static void union_fixup(un) struct union_node *un; { VOP_LOCK(un->un_uppervp); 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; { 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); VOP_LOCK(dvp); } } 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)) VOP_LOCK(dvp); 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 (mp->mnt_flag & MNT_MLOCK) { mp->mnt_flag |= MNT_MWAIT; sleep((caddr_t) mp, PVFS); continue; } if (error = VFS_ROOT(mp, &tdvp)) { vput(dvp); return (error); } vput(dvp); dvp = tdvp; } *vpp = dvp; return (0); } int union_lookup(ap) struct vop_lookup_args /* { struct vnodeop_desc *a_desc; struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; } */ *ap; { 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 componentname *cnp = ap->a_cnp; int lockparent = cnp->cn_flags & LOCKPARENT; int rdonly = cnp->cn_flags & RDONLY; struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); struct ucred *saved_cred; cnp->cn_flags |= LOCKPARENT; upperdvp = dun->un_uppervp; lowerdvp = dun->un_lowervp; uppervp = NULLVP; lowervp = NULLVP; /* * 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); uerror = union_lookup1(um->um_uppervp, &upperdvp, &uppervp, cnp); /*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); } } 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) { int nameiop; VOP_LOCK(lowerdvp); /* * 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; } 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); 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); VOP_LOCK(lowervp); 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. */ dun->un_flags &= ~UN_ULOCK; VOP_UNLOCK(upperdvp); uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); VOP_LOCK(upperdvp); dun->un_flags |= UN_ULOCK; if (uerror) { if (lowervp != NULLVP) { vput(lowervp); lowervp = NULLVP; } return (uerror); } } } if (lowervp != NULLVP) VOP_UNLOCK(lowervp); error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, uppervp, lowervp); 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); } return (error); } int union_create(ap) struct vop_create_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap; { struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp = un->un_uppervp; if (dvp != NULLVP) { int error; struct vnode *vp; FIXUP(un); VREF(dvp); un->un_flags |= UN_KLOCK; vput(ap->a_dvp); error = VOP_CREATE(dvp, &vp, ap->a_cnp, ap->a_vap); if (error) return (error); error = union_allocvp( ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, NULLVP, ap->a_cnp, vp, NULLVP); if (error) vput(vp); return (error); } vput(ap->a_dvp); return (EROFS); } int union_mknod(ap) struct vop_mknod_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap; { struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp = un->un_uppervp; if (dvp != NULLVP) { int error; struct vnode *vp; FIXUP(un); VREF(dvp); un->un_flags |= UN_KLOCK; 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, ap->a_dvp->v_mount, ap->a_dvp, NULLVP, ap->a_cnp, vp, NULLVP); if (error) vput(vp); } return (error); } vput(ap->a_dvp); return (EROFS); } int union_open(ap) 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; { 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++; VOP_LOCK(tvp); error = VOP_OPEN(tvp, mode, cred, p); VOP_UNLOCK(tvp); return (error); } FIXUP(un); error = VOP_OPEN(tvp, mode, cred, p); return (error); } int union_close(ap) struct vop_close_args /* { struct vnode *a_vp; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp; if (un->un_uppervp != NULLVP) { vp = un->un_uppervp; } else { #ifdef UNION_DIAGNOSTIC if (un->un_openl <= 0) panic("union: un_openl cnt"); #endif --un->un_openl; vp = un->un_lowervp; } return (VOP_CLOSE(vp, ap->a_fflag, ap->a_cred, ap->a_p)); } /* * 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(ap) 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; { struct union_node *un = VTOUNION(ap->a_vp); int error = EACCES; struct vnode *vp; if ((vp = un->un_uppervp) != NULLVP) { FIXUP(un); return (VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p)); } if ((vp = un->un_lowervp) != NULLVP) { VOP_LOCK(vp); error = VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p); if (error == 0) { struct union_mount *um = MOUNTTOUNIONMOUNT(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); if (error) return (error); } return (error); } /* * We handle getattr only to change the fsid and * track object sizes */ int union_getattr(ap) struct vop_getattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *ap; { int error; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp = un->un_uppervp; struct vattr *vap; struct vattr va; /* * 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; vp = un->un_uppervp; if (vp != 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); 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) { VOP_LOCK(vp); error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); VOP_UNLOCK(vp); 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(ap) struct vop_setattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); 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) && (ap->a_vap->va_size == 0)) { struct vnode *vp; error = union_vn_create(&vp, un, ap->a_p); if (error) return (error); /* at this point, uppervp is locked */ union_newupper(un, vp); VOP_UNLOCK(vp); union_vn_close(un->un_uppervp, FWRITE, ap->a_cred, ap->a_p); VOP_LOCK(vp); un->un_flags |= UN_ULOCK; } /* * Try to set attributes in upper layer, * otherwise return read-only filesystem error. */ if (un->un_uppervp != NULLVP) { FIXUP(un); 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(ap) struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; struct ucred *a_cred; } */ *ap; { int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) VOP_LOCK(vp); else FIXUP(VTOUNION(ap->a_vp)); error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); if (dolock) VOP_UNLOCK(vp); /* * 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(ap) struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; struct ucred *a_cred; } */ *ap; { int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) VOP_LOCK(vp); else FIXUP(VTOUNION(ap->a_vp)); error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); if (dolock) VOP_UNLOCK(vp); /* * the size of the underlying object may be changed by the * write. */ 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_ioctl(ap) struct vop_ioctl_args /* { struct vnode *a_vp; int a_command; caddr_t a_data; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *ap; { return (VOP_IOCTL(OTHERVP(ap->a_vp), ap->a_command, ap->a_data, ap->a_fflag, ap->a_cred, ap->a_p)); } int union_select(ap) struct vop_select_args /* { struct vnode *a_vp; int a_which; int a_fflags; struct ucred *a_cred; struct proc *a_p; } */ *ap; { return (VOP_SELECT(OTHERVP(ap->a_vp), ap->a_which, ap->a_fflags, ap->a_cred, ap->a_p)); } int union_mmap(ap) struct vop_mmap_args /* { struct vnode *a_vp; int a_fflags; struct ucred *a_cred; struct proc *a_p; } */ *ap; { return (VOP_MMAP(OTHERVP(ap->a_vp), ap->a_fflags, ap->a_cred, ap->a_p)); } int union_fsync(ap) struct vop_fsync_args /* { struct vnode *a_vp; struct ucred *a_cred; int a_waitfor; struct proc *a_p; } */ *ap; { int error = 0; struct vnode *targetvp = OTHERVP(ap->a_vp); if (targetvp != NULLVP) { int dolock = (targetvp == LOWERVP(ap->a_vp)); if (dolock) VOP_LOCK(targetvp); else FIXUP(VTOUNION(ap->a_vp)); error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, ap->a_p); if (dolock) VOP_UNLOCK(targetvp); } return (error); } int union_seek(ap) struct vop_seek_args /* { struct vnode *a_vp; off_t a_oldoff; off_t a_newoff; struct ucred *a_cred; } */ *ap; { return (VOP_SEEK(OTHERVP(ap->a_vp), ap->a_oldoff, ap->a_newoff, ap->a_cred)); } int union_remove(ap) struct vop_remove_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap; { int error; struct union_node *dun = VTOUNION(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_vp); if (dun->un_uppervp != NULLVP && un->un_uppervp != NULLVP) { struct vnode *dvp = dun->un_uppervp; struct vnode *vp = un->un_uppervp; FIXUP(dun); VREF(dvp); dun->un_flags |= UN_KLOCK; vput(ap->a_dvp); FIXUP(un); VREF(vp); un->un_flags |= UN_KLOCK; vput(ap->a_vp); error = VOP_REMOVE(dvp, vp, ap->a_cnp); if (!error) union_removed_upper(un); /* * XXX: should create a whiteout here */ } else { /* * XXX: should create a whiteout here */ vput(ap->a_dvp); vput(ap->a_vp); error = EROFS; } return (error); } int union_link(ap) struct vop_link_args /* { struct vnode *a_vp; struct vnode *a_tdvp; struct componentname *a_cnp; } */ *ap; { int error = 0; struct union_node *un; struct vnode *vp; struct vnode *tdvp; un = VTOUNION(ap->a_vp); if (ap->a_vp->v_op != ap->a_tdvp->v_op) { tdvp = ap->a_tdvp; } else { struct union_node *tdun = VTOUNION(ap->a_tdvp); if (tdun->un_uppervp == NULLVP) { VOP_LOCK(ap->a_tdvp); if (un->un_uppervp == tdun->un_dirvp) { un->un_flags &= ~UN_ULOCK; VOP_UNLOCK(un->un_uppervp); } error = union_copyup(tdun, 1, ap->a_cnp->cn_cred, ap->a_cnp->cn_proc); if (un->un_uppervp == tdun->un_dirvp) { VOP_LOCK(un->un_uppervp); un->un_flags |= UN_ULOCK; } VOP_UNLOCK(ap->a_tdvp); } tdvp = tdun->un_uppervp; } vp = un->un_uppervp; if (vp == NULLVP) error = EROFS; if (error) { vput(ap->a_vp); return (error); } FIXUP(un); VREF(vp); un->un_flags |= UN_KLOCK; vput(ap->a_vp); return (VOP_LINK(vp, tdvp, ap->a_cnp)); } int union_rename(ap) 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; { 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; if (fdvp->v_op == union_vnodeop_p) { /* always true */ struct union_node *un = VTOUNION(fdvp); if (un->un_uppervp == NULLVP) { error = EROFS; goto bad; } fdvp = un->un_uppervp; VREF(fdvp); vrele(ap->a_fdvp); } if (fvp->v_op == union_vnodeop_p) { /* always true */ struct union_node *un = VTOUNION(fvp); if (un->un_uppervp == NULLVP) { error = EROFS; goto bad; } fvp = un->un_uppervp; VREF(fvp); vrele(ap->a_fvp); } 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 = EROFS; goto bad; } 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; } vput(ap->a_tvp); } return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp)); bad: vrele(fdvp); vrele(fvp); vput(tdvp); if (tvp != NULLVP) vput(tvp); return (error); } int union_mkdir(ap) struct vop_mkdir_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap; { struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp = un->un_uppervp; if (dvp != NULLVP) { int error; struct vnode *vp; FIXUP(un); VREF(dvp); un->un_flags |= UN_KLOCK; vput(ap->a_dvp); error = VOP_MKDIR(dvp, &vp, ap->a_cnp, ap->a_vap); if (error) return (error); error = union_allocvp( ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, NULLVP, ap->a_cnp, vp, NULLVP); if (error) vput(vp); return (error); } vput(ap->a_dvp); return (EROFS); } int union_rmdir(ap) struct vop_rmdir_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap; { int error; struct union_node *dun = VTOUNION(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_vp); if (dun->un_uppervp != NULLVP && un->un_uppervp != NULLVP) { struct vnode *dvp = dun->un_uppervp; struct vnode *vp = un->un_uppervp; FIXUP(dun); VREF(dvp); dun->un_flags |= UN_KLOCK; vput(ap->a_dvp); FIXUP(un); VREF(vp); un->un_flags |= UN_KLOCK; vput(ap->a_vp); error = VOP_RMDIR(dvp, vp, ap->a_cnp); if (!error) union_removed_upper(un); /* * XXX: should create a whiteout here */ } else { /* * XXX: should create a whiteout here */ vput(ap->a_dvp); vput(ap->a_vp); error = EROFS; } return (error); } int union_symlink(ap) struct vop_symlink_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; char *a_target; } */ *ap; { struct union_node *un = VTOUNION(ap->a_dvp); struct vnode *dvp = un->un_uppervp; if (dvp != NULLVP) { int error; struct vnode *vp; struct mount *mp = ap->a_dvp->v_mount; FIXUP(un); 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(ap) struct vop_readdir_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; struct uio *a_uio; struct ucred *a_cred; int *a_eofflag; u_long *a_cookies; int a_ncookies; } */ *ap; { register struct union_node *un = VTOUNION(ap->a_vp); register struct vnode *uvp = un->un_uppervp; if (uvp == NULLVP) return (0); FIXUP(un); ap->a_vp = uvp; return (VOCALL(uvp->v_op, VOFFSET(vop_readdir), ap)); } int union_readlink(ap) struct vop_readlink_args /* { struct vnode *a_vp; struct uio *a_uio; struct ucred *a_cred; } */ *ap; { int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) VOP_LOCK(vp); else FIXUP(VTOUNION(ap->a_vp)); error = VOP_READLINK(vp, ap->a_uio, ap->a_cred); if (dolock) VOP_UNLOCK(vp); return (error); } int union_abortop(ap) struct vop_abortop_args /* { struct vnode *a_dvp; struct componentname *a_cnp; } */ *ap; { int error; struct vnode *vp = OTHERVP(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_dvp); int islocked = un->un_flags & UN_LOCKED; int dolock = (vp == LOWERVP(ap->a_dvp)); if (islocked) { if (dolock) VOP_LOCK(vp); else FIXUP(VTOUNION(ap->a_dvp)); } error = VOP_ABORTOP(vp, ap->a_cnp); if (islocked && dolock) VOP_UNLOCK(vp); return (error); } int union_inactive(ap) struct vop_inactive_args /* { struct vnode *a_vp; } */ *ap; { 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 if ((un->un_flags & UN_CACHED) == 0) vgone(ap->a_vp); return (0); } int union_reclaim(ap) struct vop_reclaim_args /* { struct vnode *a_vp; } */ *ap; { union_freevp(ap->a_vp); return (0); } int union_lock(ap) struct vop_lock_args *ap; { struct vnode *vp = ap->a_vp; struct union_node *un; start: while (vp->v_flag & VXLOCK) { vp->v_flag |= VXWANT; sleep((caddr_t)vp, PINOD); } un = VTOUNION(vp); if (un->un_uppervp != NULLVP) { if (((un->un_flags & UN_ULOCK) == 0) && (vp->v_usecount != 0)) { un->un_flags |= UN_ULOCK; VOP_LOCK(un->un_uppervp); } #ifdef DIAGNOSTIC if (un->un_flags & UN_KLOCK) panic("union: dangling upper lock"); #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_WANT; sleep((caddr_t) &un->un_flags, 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); } int union_unlock(ap) struct vop_lock_args *ap; { struct union_node *un = VTOUNION(ap->a_vp); #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); un->un_flags &= ~(UN_ULOCK|UN_KLOCK); if (un->un_flags & UN_WANT) { un->un_flags &= ~UN_WANT; wakeup((caddr_t) &un->un_flags); } #ifdef DIAGNOSTIC un->un_pid = 0; #endif return (0); } int union_bmap(ap) struct vop_bmap_args /* { struct vnode *a_vp; daddr_t a_bn; struct vnode **a_vpp; daddr_t *a_bnp; int *a_runp; } */ *ap; { int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) VOP_LOCK(vp); else FIXUP(VTOUNION(ap->a_vp)); error = VOP_BMAP(vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp); if (dolock) VOP_UNLOCK(vp); return (error); } int union_print(ap) struct vop_print_args /* { struct vnode *a_vp; } */ *ap; { struct vnode *vp = ap->a_vp; printf("\ttag VT_UNION, vp=%x, uppervp=%x, lowervp=%x\n", vp, UPPERVP(vp), LOWERVP(vp)); return (0); } int union_islocked(ap) struct vop_islocked_args /* { struct vnode *a_vp; } */ *ap; { return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0); } int union_pathconf(ap) struct vop_pathconf_args /* { struct vnode *a_vp; int a_name; int *a_retval; } */ *ap; { int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) VOP_LOCK(vp); else FIXUP(VTOUNION(ap->a_vp)); error = VOP_PATHCONF(vp, ap->a_name, ap->a_retval); if (dolock) VOP_UNLOCK(vp); return (error); } int union_advlock(ap) struct vop_advlock_args /* { struct vnode *a_vp; caddr_t a_id; int a_op; struct flock *a_fl; int a_flags; } */ *ap; { return (VOP_ADVLOCK(OTHERVP(ap->a_vp), ap->a_id, ap->a_op, ap->a_fl, ap->a_flags)); } /* * 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(ap) struct vop_strategy_args /* { struct buf *a_bp; } */ *ap; { 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); } /* * Global vfs data structures */ int (**union_vnodeop_p)(); 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_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_ioctl_desc, union_ioctl }, /* ioctl */ { &vop_select_desc, union_select }, /* select */ { &vop_mmap_desc, union_mmap }, /* mmap */ { &vop_fsync_desc, union_fsync }, /* fsync */ { &vop_seek_desc, union_seek }, /* seek */ { &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_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 */ #ifdef notdef { &vop_blkatoff_desc, union_blkatoff }, /* blkatoff */ { &vop_valloc_desc, union_valloc }, /* valloc */ { &vop_vfree_desc, union_vfree }, /* vfree */ { &vop_truncate_desc, union_truncate }, /* truncate */ { &vop_update_desc, union_update }, /* update */ { &vop_bwrite_desc, union_bwrite }, /* bwrite */ #endif { (struct vnodeop_desc*)NULL, (int(*)())NULL } }; struct vnodeopv_desc union_vnodeop_opv_desc = { &union_vnodeop_p, union_vnodeop_entries };