/* $NetBSD: union_vnops.c,v 1.70.14.1 2020/08/27 09:08:39 martin Exp $ */ /* * Copyright (c) 1992, 1993, 1994, 1995 * The Regents of the University of California. 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. 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 8.33 (Berkeley) 7/31/95 */ /* * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry. * * 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 8.33 (Berkeley) 7/31/95 */ #include __KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.70.14.1 2020/08/27 09:08:39 martin Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int union_lookup(void *); int union_create(void *); int union_whiteout(void *); int union_mknod(void *); int union_open(void *); int union_close(void *); int union_access(void *); int union_getattr(void *); int union_setattr(void *); int union_read(void *); int union_write(void *); int union_ioctl(void *); int union_poll(void *); int union_revoke(void *); int union_mmap(void *); int union_fsync(void *); int union_seek(void *); int union_remove(void *); int union_link(void *); int union_rename(void *); int union_mkdir(void *); int union_rmdir(void *); int union_symlink(void *); int union_readdir(void *); int union_readlink(void *); int union_abortop(void *); int union_inactive(void *); int union_reclaim(void *); int union_lock(void *); int union_unlock(void *); int union_bmap(void *); int union_print(void *); int union_islocked(void *); int union_pathconf(void *); int union_advlock(void *); int union_strategy(void *); int union_bwrite(void *); int union_getpages(void *); int union_putpages(void *); int union_kqfilter(void *); static int union_lookup1(struct vnode *, struct vnode **, struct vnode **, struct componentname *); /* * Global vfs data structures */ int (**union_vnodeop_p)(void *); const 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_fallocate_desc, genfs_eopnotsupp }, /* fallocate */ { &vop_fdiscard_desc, genfs_eopnotsupp }, /* fdiscard */ { &vop_ioctl_desc, union_ioctl }, /* ioctl */ { &vop_poll_desc, union_poll }, /* select */ { &vop_revoke_desc, union_revoke }, /* revoke */ { &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_bwrite_desc, union_bwrite }, /* bwrite */ { &vop_print_desc, union_print }, /* print */ { &vop_islocked_desc, union_islocked }, /* islocked */ { &vop_pathconf_desc, union_pathconf }, /* pathconf */ { &vop_advlock_desc, union_advlock }, /* advlock */ { &vop_getpages_desc, union_getpages }, /* getpages */ { &vop_putpages_desc, union_putpages }, /* putpages */ { &vop_kqfilter_desc, union_kqfilter }, /* kqfilter */ { NULL, NULL } }; const struct vnodeopv_desc union_vnodeop_opv_desc = { &union_vnodeop_p, union_vnodeop_entries }; #define NODE_IS_SPECIAL(vp) \ ((vp)->v_type == VBLK || (vp)->v_type == VCHR || \ (vp)->v_type == VSOCK || (vp)->v_type == VFIFO) static int union_lookup1(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_vflag & VV_ROOT)) { /* * 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; VOP_UNLOCK(tdvp); vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); } } error = VOP_LOOKUP(dvp, &tdvp, cnp); if (error) return (error); if (dvp != tdvp) { if (cnp->cn_flags & ISDOTDOT) VOP_UNLOCK(dvp); error = vn_lock(tdvp, LK_EXCLUSIVE); if (cnp->cn_flags & ISDOTDOT) vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); if (error) { vrele(tdvp); return error; } 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)) continue; vput(dvp); error = VFS_ROOT(mp, &tdvp); vfs_unbusy(mp); if (error) { return (error); } dvp = tdvp; } *vpp = dvp; return (0); } int union_lookup(void *v) { struct vop_lookup_v2_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 componentname *cnp = ap->a_cnp; struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); kauth_cred_t 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); return (0); } #endif if ((cnp->cn_flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) return (EROFS); start: 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) { uerror = union_lookup1(um->um_uppervp, &upperdvp, &uppervp, cnp); if (cnp->cn_consume != 0) { if (uppervp != upperdvp) VOP_UNLOCK(uppervp); *ap->a_vpp = uppervp; 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); 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); /* * 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); if (cnp->cn_consume != 0) { if (uppervp != NULLVP) { if (uppervp == upperdvp) vrele(uppervp); else vput(uppervp); uppervp = NULLVP; } *ap->a_vpp = lowervp; 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); lerror = 0; } } } /* * EJUSTRETURN is used by underlying filesystems to indicate that * a directory modification op was started successfully. * This will only happen in the upper layer, since * the lower layer only does LOOKUPs. * If this union is mounted read-only, bounce it now. */ if ((uerror == EJUSTRETURN) && (cnp->cn_flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME))) uerror = EROFS; /* * 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! * If we have to create a shadow directory and want * to commit the node we have to restart the lookup * to get the componentname right. */ if (upperdvp) { VOP_UNLOCK(upperdvp); uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY); if (uerror == 0 && cnp->cn_nameiop != LOOKUP) { vrele(uppervp); if (lowervp != NULLVP) vput(lowervp); goto start; } } if (uerror) { if (lowervp != NULLVP) { vput(lowervp); lowervp = NULLVP; } return (uerror); } } } else { /* uerror == 0 */ if (uppervp != upperdvp) VOP_UNLOCK(uppervp); } if (lowervp != NULLVP) VOP_UNLOCK(lowervp); error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, uppervp, lowervp, 1); if (error) { if (uppervp != NULLVP) vrele(uppervp); if (lowervp != NULLVP) vrele(lowervp); return error; } return 0; } int union_create(void *v) { struct vop_create_v3_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 componentname *cnp = ap->a_cnp; if (dvp != NULLVP) { int error; struct vnode *vp; struct mount *mp; mp = ap->a_dvp->v_mount; vp = NULL; 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) vrele(vp); return (error); } return (EROFS); } int union_whiteout(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 componentname *cnp = ap->a_cnp; if (un->un_uppervp == NULLVP) return (EOPNOTSUPP); return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags)); } int union_mknod(void *v) { struct vop_mknod_v3_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 componentname *cnp = ap->a_cnp; if (dvp != NULLVP) { int error; struct vnode *vp; struct mount *mp; mp = ap->a_dvp->v_mount; error = VOP_MKNOD(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) vrele(vp); return (error); } return (EROFS); } int union_open(void *v) { struct vop_open_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; int a_mode; kauth_cred_t a_cred; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *tvp; int mode = ap->a_mode; kauth_cred_t cred = ap->a_cred; struct lwp *l = curlwp; 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, l); if (error == 0) error = VOP_OPEN(un->un_uppervp, mode, cred); if (error == 0) { mutex_enter(un->un_uppervp->v_interlock); un->un_uppervp->v_writecount++; mutex_exit(un->un_uppervp->v_interlock); } return (error); } /* * Just open the lower vnode, but check for nodev mount flag */ if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) return ENXIO; un->un_openl++; vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); error = VOP_OPEN(tvp, mode, cred); VOP_UNLOCK(tvp); return (error); } /* * Just open the upper vnode, checking for nodev mount flag first */ if ((tvp->v_type == VBLK || tvp->v_type == VCHR) && (ap->a_vp->v_mount->mnt_flag & MNT_NODEV)) return ENXIO; error = VOP_OPEN(tvp, mode, cred); if (error == 0 && (ap->a_mode & FWRITE)) { mutex_enter(tvp->v_interlock); tvp->v_writecount++; mutex_exit(tvp->v_interlock); } return (error); } int union_close(void *v) { struct vop_close_args /* { struct vnode *a_vp; int a_fflag; kauth_cred_t a_cred; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp; int error; bool do_lock; vp = un->un_uppervp; if (vp != NULLVP) { do_lock = false; } else { KASSERT(un->un_openl > 0); --un->un_openl; vp = un->un_lowervp; do_lock = true; } KASSERT(vp != NULLVP); ap->a_vp = vp; if ((ap->a_fflag & FWRITE)) { KASSERT(vp == un->un_uppervp); mutex_enter(vp->v_interlock); vp->v_writecount--; mutex_exit(vp->v_interlock); } if (do_lock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); error = VCALL(vp, VOFFSET(vop_close), ap); if (do_lock) VOP_UNLOCK(vp); return error; } /* * 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(void *v) { struct vop_access_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; int a_mode; kauth_cred_t a_cred; } */ *ap = v; struct vnode *vp = ap->a_vp; struct union_node *un = VTOUNION(vp); int error = EACCES; struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount); /* * Disallow write attempts on read-only file systems; * unless the file is a socket, fifo, or a block or * character device resident on the file system. */ if (ap->a_mode & VWRITE) { switch (vp->v_type) { case VDIR: case VLNK: case VREG: if (vp->v_mount->mnt_flag & MNT_RDONLY) return (EROFS); break; case VBAD: case VBLK: case VCHR: case VSOCK: case VFIFO: case VNON: default: break; } } if ((vp = un->un_uppervp) != NULLVP) { ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_access), ap)); } if ((vp = un->un_lowervp) != NULLVP) { vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_access), ap); if (error == 0) { if (um->um_op == UNMNT_BELOW) { ap->a_cred = um->um_cred; error = VCALL(vp, VOFFSET(vop_access), ap); } } VOP_UNLOCK(vp); if (error) return (error); } return (error); } /* * We handle getattr only to change the fsid and * track object sizes */ int union_getattr(void *v) { struct vop_getattr_args /* { struct vnode *a_vp; struct vattr *a_vap; kauth_cred_t a_cred; } */ *ap = v; 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. * * To make life more interesting, some filesystems don't keep * track of link counts in the expected way, and return a * link count of `1' for those directories; if either of the * component directories returns a link count of `1', we return a 1. */ vap = ap->a_vap; vp = un->un_uppervp; if (vp != NULLVP) { error = VOP_GETATTR(vp, vap, ap->a_cred); if (error) return (error); mutex_enter(&un->un_lock); 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; if (vp != NULLVP) vap = &va; } else { vp = NULLVP; } if (vp != NULLVP) { if (vp == un->un_lowervp) vn_lock(vp, LK_SHARED | LK_RETRY); error = VOP_GETATTR(vp, vap, ap->a_cred); if (vp == un->un_lowervp) VOP_UNLOCK(vp); if (error) return (error); mutex_enter(&un->un_lock); union_newsize(ap->a_vp, VNOVAL, vap->va_size); } if ((vap != ap->a_vap) && (vap->va_type == VDIR)) { /* * Link count manipulation: * - If both return "2", return 2 (no subdirs) * - If one or the other return "1", return "1" (ENOCLUE) */ if ((ap->a_vap->va_nlink == 2) && (vap->va_nlink == 2)) ; else if (ap->a_vap->va_nlink != 1) { if (vap->va_nlink == 1) ap->a_vap->va_nlink = 1; else ap->a_vap->va_nlink += vap->va_nlink; } } ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0]; return (0); } int union_setattr(void *v) { struct vop_setattr_args /* { struct vnode *a_vp; struct vattr *a_vap; kauth_cred_t a_cred; } */ *ap = v; struct vattr *vap = ap->a_vap; struct vnode *vp = ap->a_vp; struct union_node *un = VTOUNION(vp); bool size_only; /* All but va_size are VNOVAL. */ int error; size_only = (vap->va_flags == VNOVAL && vap->va_uid == (uid_t)VNOVAL && vap->va_gid == (gid_t)VNOVAL && vap->va_atime.tv_sec == VNOVAL && vap->va_mtime.tv_sec == VNOVAL && vap->va_mode == (mode_t)VNOVAL); if (!size_only && (vp->v_mount->mnt_flag & MNT_RDONLY)) return (EROFS); if (vap->va_size != VNOVAL) { switch (vp->v_type) { case VDIR: return (EISDIR); case VCHR: case VBLK: case VSOCK: case VFIFO: break; case VREG: case VLNK: default: /* * Disallow write attempts if the filesystem is * mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return (EROFS); } } /* * 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, (vap->va_size != 0), ap->a_cred, curlwp); if (error) return (error); } /* * Try to set attributes in upper layer, ignore size change to zero * for devices to handle O_TRUNC and return read-only filesystem error * otherwise. */ if (un->un_uppervp != NULLVP) { error = VOP_SETATTR(un->un_uppervp, vap, ap->a_cred); if ((error == 0) && (vap->va_size != VNOVAL)) { mutex_enter(&un->un_lock); union_newsize(ap->a_vp, vap->va_size, VNOVAL); } } else { KASSERT(un->un_lowervp != NULLVP); if (NODE_IS_SPECIAL(un->un_lowervp)) { if (size_only && (vap->va_size == 0 || vap->va_size == VNOVAL)) error = 0; else error = EROFS; } else { error = EROFS; } } return (error); } int union_read(void *v) { struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; kauth_cred_t a_cred; } */ *ap = v; int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 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; off_t usz = VNOVAL, lsz = VNOVAL; mutex_enter(&un->un_lock); if (vp == un->un_uppervp) { if (cur > un->un_uppersz) usz = cur; } else { if (cur > un->un_lowersz) lsz = cur; } if (usz != VNOVAL || lsz != VNOVAL) union_newsize(ap->a_vp, usz, lsz); else mutex_exit(&un->un_lock); } return (error); } int union_write(void *v) { struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; kauth_cred_t a_cred; } */ *ap = v; int error; struct vnode *vp; struct union_node *un = VTOUNION(ap->a_vp); vp = UPPERVP(ap->a_vp); if (vp == NULLVP) { vp = LOWERVP(ap->a_vp); if (NODE_IS_SPECIAL(vp)) { vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); VOP_UNLOCK(vp); return error; } panic("union: missing upper layer in write"); } 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; mutex_enter(&un->un_lock); if (cur > un->un_uppersz) union_newsize(ap->a_vp, cur, VNOVAL); else mutex_exit(&un->un_lock); } return (error); } int union_ioctl(void *v) { struct vop_ioctl_args /* { struct vnode *a_vp; int a_command; void *a_data; int a_fflag; kauth_cred_t a_cred; } */ *ap = v; struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); } int union_poll(void *v) { struct vop_poll_args /* { struct vnode *a_vp; int a_events; } */ *ap = v; struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_poll), ap)); } int union_revoke(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); /* XXXAD?? */ return (0); } int union_mmap(void *v) { struct vop_mmap_args /* { struct vnode *a_vp; vm_prot_t a_prot; kauth_cred_t a_cred; } */ *ap = v; struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_mmap), ap)); } int union_fsync(void *v) { struct vop_fsync_args /* { struct vnode *a_vp; kauth_cred_t a_cred; int a_flags; off_t offhi; off_t offlo; } */ *ap = v; int error = 0; struct vnode *targetvp; /* * If vinvalbuf is calling us, it's a "shallow fsync" -- don't * bother syncing the underlying vnodes, since (a) they'll be * fsync'ed when reclaimed and (b) we could deadlock if * they're locked; otherwise, pass it through to the * underlying layer. */ if (ap->a_vp->v_type == VBLK || ap->a_vp->v_type == VCHR) { error = spec_fsync(v); if (error) return error; } if (ap->a_flags & FSYNC_RECLAIM) return 0; targetvp = OTHERVP(ap->a_vp); if (targetvp != NULLVP) { int dolock = (targetvp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY); error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags, ap->a_offlo, ap->a_offhi); if (dolock) VOP_UNLOCK(targetvp); } return (error); } int union_seek(void *v) { struct vop_seek_args /* { struct vnode *a_vp; off_t a_oldoff; off_t a_newoff; kauth_cred_t a_cred; } */ *ap = v; struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_seek), ap)); } int union_remove(void *v) { struct vop_remove_v2_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 componentname *cnp = ap->a_cnp; 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; /* Account for VOP_REMOVE to vrele vp. */ vref(vp); if (union_dowhiteout(un, cnp->cn_cred)) cnp->cn_flags |= DOWHITEOUT; error = VOP_REMOVE(dvp, vp, cnp); if (!error) union_removed_upper(un); vrele(ap->a_vp); } else { error = union_mkwhiteout( MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), dun->un_uppervp, ap->a_cnp, un); vput(ap->a_vp); } return (error); } int union_link(void *v) { struct vop_link_v2_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap = v; int error = 0; struct componentname *cnp = ap->a_cnp; struct union_node *dun; struct vnode *vp; struct vnode *dvp; dun = VTOUNION(ap->a_dvp); KASSERT((ap->a_cnp->cn_flags & LOCKPARENT) != 0); 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) { const bool droplock = (dun->un_uppervp == un->un_dirvp); /* * Needs to be copied before we can link it. */ vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); if (droplock) VOP_UNLOCK(dun->un_uppervp); error = union_copyup(un, 1, cnp->cn_cred, curlwp); if (droplock) { vn_lock(dun->un_uppervp, LK_EXCLUSIVE | LK_RETRY); /* * 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) panic("union: null upperdvp?"); error = relookup(ap->a_dvp, &vp, ap->a_cnp, 0); if (error) { VOP_UNLOCK(ap->a_vp); return EROFS; /* ? */ } if (vp != NULLVP) { /* * The name we want to create has * mysteriously appeared (a race?) */ error = EEXIST; VOP_UNLOCK(ap->a_vp); vput(vp); return (error); } } VOP_UNLOCK(ap->a_vp); } vp = un->un_uppervp; } dvp = dun->un_uppervp; if (dvp == NULLVP) error = EROFS; if (error) return (error); return VOP_LINK(dvp, vp, cnp); } int union_rename(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; /* * Account for VOP_RENAME to vrele all nodes. * Note: VOP_RENAME will unlock tdvp. */ 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); } if (fvp->v_op == union_vnodeop_p) { /* always true */ struct union_node *un = VTOUNION(fvp); if (un->un_uppervp == NULLVP) { /* XXX: should do a copyup */ error = EXDEV; goto bad; } if (un->un_lowervp != NULLVP) ap->a_fcnp->cn_flags |= DOWHITEOUT; fvp = un->un_uppervp; vref(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 = EXDEV; goto bad; } tdvp = un->un_uppervp; vref(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); } } error = VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp); goto out; bad: vput(tdvp); if (tvp != NULLVP) vput(tvp); vrele(fdvp); vrele(fvp); out: if (fdvp != ap->a_fdvp) { vrele(ap->a_fdvp); } if (fvp != ap->a_fvp) { vrele(ap->a_fvp); } if (tdvp != ap->a_tdvp) { vrele(ap->a_tdvp); } if (tvp != ap->a_tvp) { vrele(ap->a_tvp); } return (error); } int union_mkdir(void *v) { struct vop_mkdir_v3_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 componentname *cnp = ap->a_cnp; if (dvp != NULLVP) { int error; struct vnode *vp; vp = NULL; error = VOP_MKDIR(dvp, &vp, 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, cnp, vp, NULLVP, 1); if (error) vrele(vp); return (error); } return (EROFS); } int union_rmdir(void *v) { struct vop_rmdir_v2_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 componentname *cnp = ap->a_cnp; if (dun->un_uppervp == NULLVP) panic("union rmdir: null upper vnode"); error = union_check_rmdir(un, cnp->cn_cred); if (error) { vput(ap->a_vp); return error; } if (un->un_uppervp != NULLVP) { struct vnode *dvp = dun->un_uppervp; struct vnode *vp = un->un_uppervp; /* Account for VOP_RMDIR to vrele vp. */ vref(vp); if (union_dowhiteout(un, cnp->cn_cred)) cnp->cn_flags |= DOWHITEOUT; error = VOP_RMDIR(dvp, vp, ap->a_cnp); if (!error) union_removed_upper(un); vrele(ap->a_vp); } else { error = union_mkwhiteout( MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount), dun->un_uppervp, ap->a_cnp, un); vput(ap->a_vp); } return (error); } int union_symlink(void *v) { struct vop_symlink_v3_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 componentname *cnp = ap->a_cnp; if (dvp != NULLVP) { int error; error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, ap->a_target); return (error); } 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(void *v) { struct vop_readdir_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; struct uio *a_uio; kauth_cred_t a_cred; int *a_eofflag; u_long *a_cookies; int a_ncookies; } */ *ap = v; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp; int dolock, error; if (un->un_hooknode) { KASSERT(un->un_uppervp == NULLVP); KASSERT(un->un_lowervp != NULLVP); vp = un->un_lowervp; dolock = 1; } else { vp = un->un_uppervp; dolock = 0; } if (vp == NULLVP) return 0; if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_readdir), ap); if (dolock) VOP_UNLOCK(vp); return error; } int union_readlink(void *v) { struct vop_readlink_args /* { struct vnode *a_vp; struct uio *a_uio; kauth_cred_t a_cred; } */ *ap = v; int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_readlink), ap); if (dolock) VOP_UNLOCK(vp); return (error); } int union_abortop(void *v) { struct vop_abortop_args /* { struct vnode *a_dvp; struct componentname *a_cnp; } */ *ap = v; KASSERT(UPPERVP(ap->a_dvp) != NULL); ap->a_dvp = UPPERVP(ap->a_dvp); return VCALL(ap->a_dvp, VOFFSET(vop_abortop), ap); } int union_inactive(void *v) { struct vop_inactive_v2_args /* { const struct vnodeop_desc *a_desc; struct vnode *a_vp; bool *a_recycle; } */ *ap = v; struct vnode *vp = ap->a_vp; struct union_node *un = VTOUNION(vp); struct vnode **vpp; /* * 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. */ if (un->un_dircache != 0) { for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) vrele(*vpp); free(un->un_dircache, M_TEMP); un->un_dircache = 0; } *ap->a_recycle = ((un->un_cflags & UN_CACHED) == 0); return (0); } int union_reclaim(void *v) { struct vop_reclaim_v2_args /* { struct vnode *a_vp; } */ *ap = v; struct vnode *vp = ap->a_vp; struct vnode *uvp = UPPERVP(vp); VOP_UNLOCK(vp); if (uvp != NULL) { mutex_enter(uvp->v_interlock); KASSERT(vp->v_interlock == uvp->v_interlock); uvp->v_writecount -= vp->v_writecount; mutex_exit(uvp->v_interlock); } union_freevp(vp); return (0); } static int union_lock1(struct vnode *vp, struct vnode *lockvp, int flags) { struct vop_lock_args ap; ap.a_desc = VDESC(vop_lock); ap.a_vp = lockvp; ap.a_flags = flags; if (lockvp == vp) return genfs_lock(&ap); else return VCALL(ap.a_vp, VOFFSET(vop_lock), &ap); } static int union_unlock1(struct vnode *vp, struct vnode *lockvp) { struct vop_unlock_args ap; ap.a_desc = VDESC(vop_unlock); ap.a_vp = lockvp; if (lockvp == vp) return genfs_unlock(&ap); else return VCALL(ap.a_vp, VOFFSET(vop_unlock), &ap); } int union_lock(void *v) { struct vop_lock_args /* { struct vnode *a_vp; int a_flags; } */ *ap = v; struct vnode *vp = ap->a_vp, *lockvp; struct union_node *un = VTOUNION(vp); int flags = ap->a_flags; int error; if ((flags & LK_NOWAIT) != 0) { if (!mutex_tryenter(&un->un_lock)) return EBUSY; lockvp = LOCKVP(vp); error = union_lock1(vp, lockvp, flags); mutex_exit(&un->un_lock); if (error) return error; if (mutex_tryenter(vp->v_interlock)) { error = vdead_check(vp, VDEAD_NOWAIT); mutex_exit(vp->v_interlock); } else error = EBUSY; if (error) union_unlock1(vp, lockvp); return error; } mutex_enter(&un->un_lock); for (;;) { lockvp = LOCKVP(vp); mutex_exit(&un->un_lock); error = union_lock1(vp, lockvp, flags); if (error != 0) return error; mutex_enter(&un->un_lock); if (lockvp == LOCKVP(vp)) break; union_unlock1(vp, lockvp); } mutex_exit(&un->un_lock); mutex_enter(vp->v_interlock); error = vdead_check(vp, VDEAD_NOWAIT); if (error) { union_unlock1(vp, lockvp); error = vdead_check(vp, 0); KASSERT(error == ENOENT); } mutex_exit(vp->v_interlock); return error; } int union_unlock(void *v) { struct vop_unlock_args /* { struct vnode *a_vp; int a_flags; } */ *ap = v; struct vnode *vp = ap->a_vp, *lockvp; lockvp = LOCKVP(vp); union_unlock1(vp, lockvp); return 0; } int union_bmap(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 vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_bmap), ap); if (dolock) VOP_UNLOCK(vp); return (error); } int union_print(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) != NULLVP) vprint("union: upper", UPPERVP(vp)); if (LOWERVP(vp) != NULLVP) vprint("union: lower", 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(void *v) { struct vop_islocked_args /* { struct vnode *a_vp; } */ *ap = v; struct vnode *vp; struct union_node *un; un = VTOUNION(ap->a_vp); mutex_enter(&un->un_lock); vp = LOCKVP(ap->a_vp); mutex_exit(&un->un_lock); if (vp == ap->a_vp) return genfs_islocked(ap); else return VOP_ISLOCKED(vp); } int union_pathconf(void *v) { struct vop_pathconf_args /* { struct vnode *a_vp; int a_name; int *a_retval; } */ *ap = v; int error; struct vnode *vp = OTHERVP(ap->a_vp); int dolock = (vp == LOWERVP(ap->a_vp)); if (dolock) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_pathconf), ap); if (dolock) VOP_UNLOCK(vp); return (error); } int union_advlock(void *v) { struct vop_advlock_args /* { struct vnode *a_vp; void *a_id; int a_op; struct flock *a_fl; int a_flags; } */ *ap = v; struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_advlock), ap)); } int union_strategy(void *v) { struct vop_strategy_args /* { struct vnode *a_vp; struct buf *a_bp; } */ *ap = v; struct vnode *ovp = OTHERVP(ap->a_vp); struct buf *bp = ap->a_bp; KASSERT(ovp != NULLVP); if (!NODE_IS_SPECIAL(ovp)) KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp)); return (VOP_STRATEGY(ovp, bp)); } int union_bwrite(void *v) { struct vop_bwrite_args /* { struct vnode *a_vp; struct buf *a_bp; } */ *ap = v; struct vnode *ovp = OTHERVP(ap->a_vp); struct buf *bp = ap->a_bp; KASSERT(ovp != NULLVP); if (!NODE_IS_SPECIAL(ovp)) KASSERT((bp->b_flags & B_READ) || ovp != LOWERVP(bp->b_vp)); return (VOP_BWRITE(ovp, bp)); } int union_getpages(void *v) { struct vop_getpages_args /* { struct vnode *a_vp; voff_t a_offset; struct vm_page **a_m; int *a_count; int a_centeridx; vm_prot_t a_access_type; int a_advice; int a_flags; } */ *ap = v; struct vnode *vp = ap->a_vp; KASSERT(mutex_owned(vp->v_interlock)); if (ap->a_flags & PGO_LOCKED) { return EBUSY; } ap->a_vp = OTHERVP(vp); KASSERT(vp->v_interlock == ap->a_vp->v_interlock); /* Just pass the request on to the underlying layer. */ return VCALL(ap->a_vp, VOFFSET(vop_getpages), ap); } int union_putpages(void *v) { struct vop_putpages_args /* { struct vnode *a_vp; voff_t a_offlo; voff_t a_offhi; int a_flags; } */ *ap = v; struct vnode *vp = ap->a_vp; KASSERT(mutex_owned(vp->v_interlock)); ap->a_vp = OTHERVP(vp); KASSERT(vp->v_interlock == ap->a_vp->v_interlock); if (ap->a_flags & PGO_RECLAIM) { mutex_exit(vp->v_interlock); return 0; } /* Just pass the request on to the underlying layer. */ return VCALL(ap->a_vp, VOFFSET(vop_putpages), ap); } int union_kqfilter(void *v) { struct vop_kqfilter_args /* { struct vnode *a_vp; struct knote *a_kn; } */ *ap = v; int error; /* * We watch either the upper layer file (if it already exists), * or the lower layer one. If there is lower layer file only * at this moment, we will keep watching that lower layer file * even if upper layer file would be created later on. */ if (UPPERVP(ap->a_vp)) error = VOP_KQFILTER(UPPERVP(ap->a_vp), ap->a_kn); else if (LOWERVP(ap->a_vp)) error = VOP_KQFILTER(LOWERVP(ap->a_vp), ap->a_kn); else { /* panic? */ error = EOPNOTSUPP; } return (error); }