diff options
Diffstat (limited to 'sys/fs/unionfs/union_vnops.c')
| -rw-r--r-- | sys/fs/unionfs/union_vnops.c | 1981 |
1 files changed, 1981 insertions, 0 deletions
diff --git a/sys/fs/unionfs/union_vnops.c b/sys/fs/unionfs/union_vnops.c new file mode 100644 index 0000000..03d41a0 --- /dev/null +++ b/sys/fs/unionfs/union_vnops.c @@ -0,0 +1,1981 @@ +/* + * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry. + * 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. 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 8.32 (Berkeley) 6/23/95 + * $FreeBSD$ + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/proc.h> +#include <sys/fcntl.h> +#include <sys/stat.h> +#include <sys/kernel.h> +#include <sys/vnode.h> +#include <sys/mount.h> +#include <sys/namei.h> +#include <sys/malloc.h> +#include <sys/buf.h> +#include <sys/lock.h> +#include <sys/sysctl.h> +#include <miscfs/union/union.h> + +#include <vm/vm.h> +#include <vm/vnode_pager.h> + +#include <vm/vm_page.h> +#include <vm/vm_object.h> + +int uniondebug = 0; + +#if UDEBUG_ENABLED +SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RW, &uniondebug, 0, ""); +#else +SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RD, &uniondebug, 0, ""); +#endif + +static int union_access __P((struct vop_access_args *ap)); +static int union_advlock __P((struct vop_advlock_args *ap)); +static int union_bmap __P((struct vop_bmap_args *ap)); +static int union_close __P((struct vop_close_args *ap)); +static int union_create __P((struct vop_create_args *ap)); +static int union_fsync __P((struct vop_fsync_args *ap)); +static int union_getattr __P((struct vop_getattr_args *ap)); +static int union_inactive __P((struct vop_inactive_args *ap)); +static int union_ioctl __P((struct vop_ioctl_args *ap)); +static int union_lease __P((struct vop_lease_args *ap)); +static int union_link __P((struct vop_link_args *ap)); +static int union_lock __P((struct vop_lock_args *ap)); +static int union_lookup __P((struct vop_lookup_args *ap)); +static int union_lookup1 __P((struct vnode *udvp, struct vnode **dvp, + struct vnode **vpp, + struct componentname *cnp)); +static int union_mkdir __P((struct vop_mkdir_args *ap)); +static int union_mknod __P((struct vop_mknod_args *ap)); +static int union_mmap __P((struct vop_mmap_args *ap)); +static int union_open __P((struct vop_open_args *ap)); +static int union_pathconf __P((struct vop_pathconf_args *ap)); +static int union_print __P((struct vop_print_args *ap)); +static int union_read __P((struct vop_read_args *ap)); +static int union_readdir __P((struct vop_readdir_args *ap)); +static int union_readlink __P((struct vop_readlink_args *ap)); +static int union_reclaim __P((struct vop_reclaim_args *ap)); +static int union_remove __P((struct vop_remove_args *ap)); +static int union_rename __P((struct vop_rename_args *ap)); +static int union_revoke __P((struct vop_revoke_args *ap)); +static int union_rmdir __P((struct vop_rmdir_args *ap)); +static int union_poll __P((struct vop_poll_args *ap)); +static int union_setattr __P((struct vop_setattr_args *ap)); +static int union_strategy __P((struct vop_strategy_args *ap)); +static int union_getpages __P((struct vop_getpages_args *ap)); +static int union_putpages __P((struct vop_putpages_args *ap)); +static int union_symlink __P((struct vop_symlink_args *ap)); +static int union_unlock __P((struct vop_unlock_args *ap)); +static int union_whiteout __P((struct vop_whiteout_args *ap)); +static int union_write __P((struct vop_read_args *ap)); + +static __inline +struct vnode * +union_lock_upper(struct union_node *un, struct proc *p) +{ + struct vnode *uppervp; + + if ((uppervp = un->un_uppervp) != NULL) { + VREF(uppervp); + vn_lock(uppervp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, p); + } + KASSERT((uppervp == NULL || uppervp->v_usecount > 0), ("uppervp usecount is 0")); + return(uppervp); +} + +static __inline +void +union_unlock_upper(struct vnode *uppervp, struct proc *p) +{ + vput(uppervp); +} + +static __inline +struct vnode * +union_lock_other(struct union_node *un, struct proc *p) +{ + struct vnode *vp; + + if (un->un_uppervp != NULL) { + vp = union_lock_upper(un, p); + } else if ((vp = un->un_lowervp) != NULL) { + VREF(vp); + vn_lock(vp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, p); + } + return(vp); +} + +static __inline +void +union_unlock_other(struct vnode *vp, struct proc *p) +{ + vput(vp); +} + +/* + * union_lookup: + * + * udvp must be exclusively locked on call and will remain + * exclusively locked on return. This is the mount point + * for out filesystem. + * + * dvp Our base directory, locked and referenced. + * The passed dvp will be dereferenced and unlocked on return + * and a new dvp will be returned which is locked and + * referenced in the same variable. + * + * vpp is filled in with the result if no error occured, + * locked and ref'd. + * + * If an error is returned, *vpp is set to NULLVP. If no + * error occurs, *vpp is returned with a reference and an + * exclusive lock. + */ + +static int +union_lookup1(udvp, pdvp, vpp, cnp) + struct vnode *udvp; + struct vnode **pdvp; + struct vnode **vpp; + struct componentname *cnp; +{ + int error; + struct proc *p = cnp->cn_proc; + struct vnode *dvp = *pdvp; + struct vnode *tdvp; + struct mount *mp; + + /* + * 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; + dvp = dvp->v_mount->mnt_vnodecovered; + VREF(dvp); + vput(tdvp); + vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); + } + } + + /* + * Set return dvp to be the upperdvp 'parent directory. + */ + *pdvp = dvp; + + /* + * If the VOP_LOOKUP call generates an error, tdvp is invalid and no + * changes will have been made to dvp, so we are set to return. + */ + + error = VOP_LOOKUP(dvp, &tdvp, cnp); + if (error) { + UDEBUG(("dvp %p error %d flags %lx\n", dvp, error, cnp->cn_flags)); + *vpp = NULL; + return (error); + } + + /* + * The parent directory will have been unlocked, unless lookup + * found the last component or if dvp == tdvp (tdvp must be locked). + * + * We want our dvp to remain locked and ref'd. We also want tdvp + * to remain locked and ref'd. + */ + UDEBUG(("parentdir %p result %p flag %lx\n", dvp, tdvp, cnp->cn_flags)); + + if (dvp != tdvp && (cnp->cn_flags & ISLASTCN) == 0) + vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); + + /* + * 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). + * + * We use dvp as a temporary variable here, it is no longer related + * to the dvp above. However, we have to ensure that both *pdvp and + * tdvp are locked on return. + */ + + dvp = tdvp; + while ( + dvp != udvp && + (dvp->v_type == VDIR) && + (mp = dvp->v_mountedhere) + ) { + int relock_pdvp = 0; + + if (vfs_busy(mp, 0, 0, p)) + continue; + + if (dvp == *pdvp) + relock_pdvp = 1; + vput(dvp); + dvp = NULL; + error = VFS_ROOT(mp, &dvp); + + vfs_unbusy(mp, p); + + if (relock_pdvp) + vn_lock(*pdvp, LK_EXCLUSIVE | LK_RETRY, p); + + if (error) { + *vpp = NULL; + return (error); + } + } + *vpp = dvp; + return (0); +} + +static 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; /* starting dir */ + struct union_node *dun = VTOUNION(dvp); /* associated union node */ + struct componentname *cnp = ap->a_cnp; + struct proc *p = cnp->cn_proc; + int lockparent = cnp->cn_flags & LOCKPARENT; + struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); + struct ucred *saved_cred = NULL; + int iswhiteout; + struct vattr va; + + *ap->a_vpp = NULLVP; + + /* + * Disallow write attemps to the filesystem mounted read-only. + */ + if ((cnp->cn_flags & ISLASTCN) && + (dvp->v_mount->mnt_flag & MNT_RDONLY) && + (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { + return (EROFS); + } + + /* + * For any lookup's we do, always return with the parent locked + */ + cnp->cn_flags |= LOCKPARENT; + + lowerdvp = dun->un_lowervp; + uppervp = NULLVP; + lowervp = NULLVP; + iswhiteout = 0; + + uerror = ENOENT; + lerror = ENOENT; + + /* + * Get a private lock on uppervp and a reference, effectively + * taking it out of the union_node's control. + * + * We must lock upperdvp while holding our lock on dvp + * to avoid a deadlock. + */ + upperdvp = union_lock_upper(dun, p); + + /* + * 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) { + /* + * We do not have to worry about the DOTDOT case, we've + * already unlocked dvp. + */ + UDEBUG(("A %p\n", upperdvp)); + + /* + * Do the lookup. We must supply a locked and referenced + * upperdvp to the function and will get a new locked and + * referenced upperdvp back with the old having been + * dereferenced. + * + * If an error is returned, uppervp will be NULLVP. If no + * error occurs, uppervp will be the locked and referenced + * return vnode or possibly NULL, depending on what is being + * requested. It is possible that the returned uppervp + * will be the same as upperdvp. + */ + uerror = union_lookup1(um->um_uppervp, &upperdvp, &uppervp, cnp); + UDEBUG(( + "uerror %d upperdvp %p %d/%d, uppervp %p ref=%d/lck=%d\n", + uerror, + upperdvp, + upperdvp->v_usecount, + VOP_ISLOCKED(upperdvp, NULL), + uppervp, + (uppervp ? uppervp->v_usecount : -99), + (uppervp ? VOP_ISLOCKED(uppervp, NULL) : -99) + )); + + /* + * Disallow write attemps to the filesystem mounted read-only. + */ + if (uerror == EJUSTRETURN && (cnp->cn_flags & ISLASTCN) && + (dvp->v_mount->mnt_flag & MNT_RDONLY) && + (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME)) { + error = EROFS; + goto out; + } + + /* + * Special case. If cn_consume != 0 skip out. The result + * of the lookup is transfered to our return variable. If + * an error occured we have to throw away the results. + */ + + if (cnp->cn_consume != 0) { + if ((error = uerror) == 0) { + *ap->a_vpp = uppervp; + uppervp = NULL; + } + goto out; + } + + /* + * Calculate whiteout, fall through + */ + + if (uerror == ENOENT || uerror == EJUSTRETURN) { + if (cnp->cn_flags & ISWHITEOUT) { + iswhiteout = 1; + } else if (lowerdvp != NULLVP) { + int terror; + + terror = VOP_GETATTR(upperdvp, &va, + cnp->cn_cred, cnp->cn_proc); + if (terror == 0 && (va.va_flags & OPAQUE)) + iswhiteout = 1; + } + } + } + + /* + * 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; + + UDEBUG(("B %p\n", lowerdvp)); + + /* + * Force only LOOKUPs on the lower 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. + * + * union_lookup1() requires lowervp to be locked on entry, + * and it will be unlocked on return. The ref count will + * not change. On return lowervp doesn't represent anything + * to us so we NULL it out. + */ + VREF(lowerdvp); + vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY, p); + lerror = union_lookup1(um->um_lowervp, &lowerdvp, &lowervp, cnp); + if (lowerdvp == lowervp) + vrele(lowerdvp); + else + vput(lowerdvp); + lowerdvp = NULL; /* lowerdvp invalid after vput */ + + if (um->um_op == UNMNT_BELOW) + cnp->cn_cred = saved_cred; + cnp->cn_nameiop = nameiop; + + if (cnp->cn_consume != 0 || lerror == EACCES) { + if ((error = lerror) == 0) { + *ap->a_vpp = lowervp; + lowervp = NULL; + } + goto out; + } + } else { + UDEBUG(("C %p\n", lowerdvp)); + if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { + if ((lowervp = LOWERVP(dun->un_pvp)) != NULL) { + VREF(lowervp); + vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY, p); + lerror = 0; + } + } + } + + /* + * Ok. Now we have uerror, uppervp, upperdvp, lerror, and lowervp. + * + * 1. If both layers returned an error, select the upper layer. + * + * 2. If the upper layer faile and the bottom layer succeeded, + * 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 button vnode is a directory, in which case + * create a new directory in the top layer and + * and fall through to 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. + */ + + /* case 1. */ + if ((uerror != 0) && (lerror != 0)) { + error = uerror; + goto out; + } + + /* case 2. */ + if (uerror != 0 /* && (lerror == 0) */ ) { + if (lowervp->v_type == VDIR) { /* case 2b. */ + KASSERT(uppervp == NULL, ("uppervp unexpectedly non-NULL")); + /* + * oops, uppervp has a problem, we may have to shadow. + */ + uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); + if (uerror) { + error = uerror; + goto out; + } + } + } + + /* + * Must call union_allocvp with both the upper and lower vnodes + * referenced and the upper vnode locked. ap->a_vpp is returned + * referenced and locked. lowervp, uppervp, and upperdvp are + * absorbed by union_allocvp() whether it succeeds or fails. + * + * upperdvp is the parent directory of uppervp which may be + * different, depending on the path, from dvp->un_uppervp. That's + * why it is a separate argument. Note that it must be unlocked. + * + * dvp must be locked on entry to the call and will be locked on + * return. + */ + + if (uppervp && uppervp != upperdvp) + VOP_UNLOCK(uppervp, 0, p); + if (lowervp) + VOP_UNLOCK(lowervp, 0, p); + if (upperdvp) + VOP_UNLOCK(upperdvp, 0, p); + + error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, + uppervp, lowervp, 1); + + UDEBUG(("Create %p = %p %p refs=%d\n", *ap->a_vpp, uppervp, lowervp, (*ap->a_vpp) ? ((*ap->a_vpp)->v_usecount) : -99)); + + uppervp = NULL; + upperdvp = NULL; + lowervp = NULL; + + /* + * Termination Code + * + * - put away any extra junk laying around. Note that lowervp + * (if not NULL) will never be the same as *ap->a_vp and + * neither will uppervp, because when we set that state we + * NULL-out lowervp or uppervp. On the otherhand, upperdvp + * may match uppervp or *ap->a_vpp. + * + * - relock/unlock dvp if appropriate. + */ + +out: + if (upperdvp) { + if (upperdvp == uppervp || upperdvp == *ap->a_vpp) + vrele(upperdvp); + else + vput(upperdvp); + } + + if (uppervp) + vput(uppervp); + + if (lowervp) + vput(lowervp); + + /* + * Restore LOCKPARENT state + */ + + if (!lockparent) + cnp->cn_flags &= ~LOCKPARENT; + + UDEBUG(("Out %d vpp %p/%d lower %p upper %p\n", error, *ap->a_vpp, + ((*ap->a_vpp) ? (*ap->a_vpp)->v_usecount : -99), + lowervp, uppervp)); + + /* + * dvp lock state, determine whether to relock dvp. dvp is expected + * to be locked on return if: + * + * - there was an error (except not EJUSTRETURN), or + * - we hit the last component and lockparent is true + * + * dvp_is_locked is the current state of the dvp lock, not counting + * the possibility that *ap->a_vpp == dvp (in which case it is locked + * anyway). Note that *ap->a_vpp == dvp only if no error occured. + */ + + if (*ap->a_vpp != dvp) { + if ((error == 0 || error == EJUSTRETURN) && + (!lockparent || (cnp->cn_flags & ISLASTCN) == 0)) { + VOP_UNLOCK(dvp, 0, p); + } + } + + /* + * Diagnostics + */ + +#ifdef DIAGNOSTIC + if (cnp->cn_namelen == 1 && + cnp->cn_nameptr[0] == '.' && + *ap->a_vpp != dvp) { + panic("union_lookup returning . (%p) not same as startdir (%p)", ap->a_vpp, dvp); + } +#endif + + return (error); +} + +/* + * union_create: + * + * a_dvp is locked on entry and remains locked on return. a_vpp is returned + * locked if no error occurs, otherwise it is garbage. + */ + +static 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 *dun = VTOUNION(ap->a_dvp); + struct componentname *cnp = ap->a_cnp; + struct proc *p = cnp->cn_proc; + struct vnode *dvp; + int error = EROFS; + + if ((dvp = union_lock_upper(dun, p)) != NULL) { + struct vnode *vp; + struct mount *mp; + + error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); + if (error == 0) { + mp = ap->a_dvp->v_mount; + VOP_UNLOCK(vp, 0, p); + UDEBUG(("ALLOCVP-1 FROM %p REFS %d\n", vp, vp->v_usecount)); + error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, + cnp, vp, NULLVP, 1); + UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount)); + } + union_unlock_upper(dvp, p); + } + return (error); +} + +static int +union_whiteout(ap) + struct vop_whiteout_args /* { + struct vnode *a_dvp; + struct componentname *a_cnp; + int a_flags; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_dvp); + struct componentname *cnp = ap->a_cnp; + struct vnode *uppervp; + int error = EOPNOTSUPP; + + if ((uppervp = union_lock_upper(un, cnp->cn_proc)) != NULLVP) { + error = VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags); + union_unlock_upper(uppervp, cnp->cn_proc); + } + return(error); +} + +/* + * union_mknod: + * + * a_dvp is locked on entry and should remain locked on return. + * a_vpp is garbagre whether an error occurs or not. + */ + +static 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 *dun = VTOUNION(ap->a_dvp); + struct componentname *cnp = ap->a_cnp; + struct vnode *dvp; + int error = EROFS; + + if ((dvp = union_lock_upper(dun, cnp->cn_proc)) != NULL) { + error = VOP_MKNOD(dvp, ap->a_vpp, cnp, ap->a_vap); + union_unlock_upper(dvp, cnp->cn_proc); + } + return (error); +} + +/* + * union_open: + * + * run open VOP. When opening the underlying vnode we have to mimic + * vn_open. What we *really* need to do to avoid screwups if the + * open semantics change is to call vn_open(). For example, ufs blows + * up if you open a file but do not vmio it prior to writing. + */ + +static 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 = 0; + int tvpisupper = 1; + + /* + * If there is an existing upper vp then simply open that. + * The upper vp takes precedence over the lower vp. When opening + * a lower vp for writing copy it to the uppervp and then open the + * uppervp. + * + * At the end of this section tvp will be left locked. + */ + if ((tvp = union_lock_upper(un, p)) == 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)) { + int docopy = !(mode & O_TRUNC); + error = union_copyup(un, docopy, cred, p); + tvp = union_lock_upper(un, p); + } else { + un->un_openl++; + VREF(tvp); + vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, p); + tvpisupper = 0; + } + } + + /* + * We are holding the correct vnode, open it + */ + + if (error == 0) + error = VOP_OPEN(tvp, mode, cred, p); + + /* + * Absolutely necessary or UFS will blowup + */ + if (error == 0 && vn_canvmio(tvp) == TRUE) { + error = vfs_object_create(tvp, p, cred); + } + + /* + * Release any locks held + */ + if (tvpisupper) { + if (tvp) + union_unlock_upper(tvp, p); + } else { + vput(tvp); + } + return (error); +} + +/* + * union_close: + * + * It is unclear whether a_vp is passed locked or unlocked. Whatever + * the case we do not change it. + */ + +static 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 ((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; + } + 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. + */ +static 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); + struct proc *p = ap->a_p; + int error = EACCES; + struct vnode *vp; + + /* + * Disallow write attempts on filesystems mounted read-only. + */ + if ((ap->a_mode & VWRITE) && + (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)) { + switch (ap->a_vp->v_type) { + case VREG: + case VDIR: + case VLNK: + return (EROFS); + default: + break; + } + } + + if ((vp = union_lock_upper(un, p)) != NULLVP) { + ap->a_vp = vp; + error = VCALL(vp, VOFFSET(vop_access), ap); + union_unlock_upper(vp, p); + return(error); + } + + if ((vp = un->un_lowervp) != NULLVP) { + vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); + ap->a_vp = vp; + + /* + * Remove VWRITE from a_mode if our mount point is RW, because + * we want to allow writes and lowervp may be read-only. + */ + if ((un->un_vnode->v_mount->mnt_flag & MNT_RDONLY) == 0) + ap->a_mode &= ~VWRITE; + + error = VCALL(vp, VOFFSET(vop_access), ap); + if (error == 0) { + struct union_mount *um; + + um = MOUNTTOUNIONMOUNT(un->un_vnode->v_mount); + + if (um->um_op == UNMNT_BELOW) { + ap->a_cred = um->um_cred; + error = VCALL(vp, VOFFSET(vop_access), ap); + } + } + VOP_UNLOCK(vp, 0, p); + } + return(error); +} + +/* + * We handle getattr only to change the fsid and + * track object sizes + * + * 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. + * + * Because of this we cannot use our normal locking functions + * if we do not intend to lock the main a_vp node. At the moment + * we are running without any specific locking at all, but beware + * to any programmer that care must be taken if locking is added + * to this function. + */ + +static 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; + 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; + + if ((vp = un->un_uppervp) != NULLVP) { + error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); + if (error) + return (error); + /* XXX isn't this dangerouso without a lock? */ + union_newsize(ap->a_vp, vap->va_size, VNOVAL); + } + + if (vp == NULLVP) { + vp = un->un_lowervp; + } else if (vp->v_type == VDIR && un->un_lowervp != NULLVP) { + 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); + /* XXX isn't this dangerous without a lock? */ + 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; + return (0); +} + +static 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); + struct proc *p = ap->a_p; + struct vattr *vap = ap->a_vap; + struct vnode *uppervp; + int error; + + /* + * Disallow write attempts on filesystems mounted read-only. + */ + if ((ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) && + (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)) { + 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 && (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. + */ + error = EROFS; + if ((uppervp = union_lock_upper(un, p)) != NULLVP) { + 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); + union_unlock_upper(uppervp, p); + } + return (error); +} + +/* + * union_getpages: + */ + +static int +union_getpages(struct vop_getpages_args *ap) +{ + int r; + + r = vnode_pager_generic_getpages(ap->a_vp, ap->a_m, + ap->a_count, ap->a_reqpage); + return(r); +} + +/* + * union_putpages: + */ + +static int +union_putpages(struct vop_putpages_args *ap) +{ + int r; + + r = vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count, + ap->a_sync, ap->a_rtvals); + return(r); +} + +static int +union_read(ap) + struct vop_read_args /* { + struct vnode *a_vp; + struct uio *a_uio; + int a_ioflag; + struct ucred *a_cred; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + struct proc *p = ap->a_uio->uio_procp; + struct vnode *uvp; + int error; + + uvp = union_lock_other(un, p); + KASSERT(uvp != NULL, ("union_read: backing vnode missing!")); + + if (ap->a_vp->v_flag & VOBJBUF) + union_vm_coherency(ap->a_vp, ap->a_uio, 0); + + error = VOP_READ(uvp, ap->a_uio, ap->a_ioflag, ap->a_cred); + union_unlock_other(uvp, 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 (uvp == 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); +} + +static int +union_write(ap) + struct vop_read_args /* { + struct vnode *a_vp; + struct uio *a_uio; + int a_ioflag; + struct ucred *a_cred; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + struct proc *p = ap->a_uio->uio_procp; + struct vnode *uppervp; + int error; + + if ((uppervp = union_lock_upper(un, p)) == NULLVP) + panic("union: missing upper layer in write"); + + /* + * Since our VM pages are associated with our vnode rather then + * the real vnode, and since we do not run our reads and writes + * through our own VM cache, we have a VM/VFS coherency problem. + * We solve them by invalidating or flushing the associated VM + * pages prior to allowing a normal read or write to occur. + * + * VM-backed writes (UIO_NOCOPY) have to be converted to normal + * writes because we are not cache-coherent. Normal writes need + * to be made coherent with our VM-backing store, which we do by + * first flushing any dirty VM pages associated with the write + * range, and then destroying any clean VM pages associated with + * the write range. + */ + + if (ap->a_uio->uio_segflg == UIO_NOCOPY) { + ap->a_uio->uio_segflg = UIO_SYSSPACE; + } else if (ap->a_vp->v_flag & VOBJBUF) { + union_vm_coherency(ap->a_vp, ap->a_uio, 1); + } + + error = VOP_WRITE(uppervp, 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); + } + union_unlock_upper(uppervp, p); + return (error); +} + +static int +union_lease(ap) + struct vop_lease_args /* { + struct vnode *a_vp; + struct proc *a_p; + struct ucred *a_cred; + int a_flag; + } */ *ap; +{ + struct vnode *ovp = OTHERVP(ap->a_vp); + + ap->a_vp = ovp; + return (VCALL(ovp, VOFFSET(vop_lease), ap)); +} + +static 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; +{ + struct vnode *ovp = OTHERVP(ap->a_vp); + + ap->a_vp = ovp; + return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); +} + +static int +union_poll(ap) + struct vop_poll_args /* { + struct vnode *a_vp; + int a_events; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + struct vnode *ovp = OTHERVP(ap->a_vp); + + ap->a_vp = ovp; + return (VCALL(ovp, VOFFSET(vop_poll), ap)); +} + +static int +union_revoke(ap) + struct vop_revoke_args /* { + struct vnode *a_vp; + int a_flags; + struct proc *a_p; + } */ *ap; +{ + 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); +} + +static int +union_mmap(ap) + struct vop_mmap_args /* { + struct vnode *a_vp; + int a_fflags; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + struct vnode *ovp = OTHERVP(ap->a_vp); + + ap->a_vp = ovp; + return (VCALL(ovp, VOFFSET(vop_mmap), ap)); +} + +static 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 proc *p = ap->a_p; + struct vnode *targetvp; + struct union_node *un = VTOUNION(ap->a_vp); + + if ((targetvp = union_lock_other(un, p)) != NULLVP) { + error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, p); + union_unlock_other(targetvp, p); + } + + return (error); +} + +/* + * union_remove: + * + * Remove the specified cnp. The dvp and vp are passed to us locked + * and must remain locked on return. + */ + +static int +union_remove(ap) + struct vop_remove_args /* { + struct vnode *a_dvp; + struct vnode *a_vp; + struct componentname *a_cnp; + } */ *ap; +{ + struct union_node *dun = VTOUNION(ap->a_dvp); + struct union_node *un = VTOUNION(ap->a_vp); + struct componentname *cnp = ap->a_cnp; + struct proc *p = cnp->cn_proc; + struct vnode *uppervp; + struct vnode *upperdvp; + int error; + + if ((upperdvp = union_lock_upper(dun, p)) == NULLVP) + panic("union remove: null upper vnode"); + + if ((uppervp = union_lock_upper(un, p)) != NULLVP) { + if (union_dowhiteout(un, cnp->cn_cred, p)) + cnp->cn_flags |= DOWHITEOUT; + error = VOP_REMOVE(upperdvp, uppervp, cnp); +#if 0 + /* XXX */ + if (!error) + union_removed_upper(un); +#endif + union_unlock_upper(uppervp, p); + } else { + error = union_mkwhiteout( + MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount), + upperdvp, ap->a_cnp, un->un_path); + } + union_unlock_upper(upperdvp, p); + return (error); +} + +/* + * union_link: + * + * tdvp will be locked on entry, vp will not be locked on entry. + * tdvp should remain locked on return and vp should remain unlocked + * on return. + */ + +static int +union_link(ap) + struct vop_link_args /* { + struct vnode *a_tdvp; + struct vnode *a_vp; + struct componentname *a_cnp; + } */ *ap; +{ + struct componentname *cnp = ap->a_cnp; + struct proc *p = cnp->cn_proc; + struct union_node *dun = VTOUNION(ap->a_tdvp); + struct vnode *vp; + struct vnode *tdvp; + int error = 0; + + if (ap->a_tdvp->v_op != ap->a_vp->v_op) { + vp = ap->a_vp; + } else { + struct union_node *tun = VTOUNION(ap->a_vp); + + if (tun->un_uppervp == NULLVP) { + vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, p); +#if 0 + if (dun->un_uppervp == tun->un_dirvp) { + if (dun->un_flags & UN_ULOCK) { + dun->un_flags &= ~UN_ULOCK; + VOP_UNLOCK(dun->un_uppervp, 0, p); + } + } +#endif + error = union_copyup(tun, 1, cnp->cn_cred, p); +#if 0 + if (dun->un_uppervp == tun->un_dirvp) { + vn_lock(dun->un_uppervp, + LK_EXCLUSIVE | LK_RETRY, p); + dun->un_flags |= UN_ULOCK; + } +#endif + VOP_UNLOCK(ap->a_vp, 0, p); + } + vp = tun->un_uppervp; + } + + if (error) + return (error); + + /* + * Make sure upper is locked, then unlock the union directory we were + * called with to avoid a deadlock while we are calling VOP_LINK on + * the upper (with tdvp locked and vp not locked). Our ap->a_tdvp + * is expected to be locked on return. + */ + + if ((tdvp = union_lock_upper(dun, p)) == NULLVP) + return (EROFS); + + VOP_UNLOCK(ap->a_tdvp, 0, p); /* unlock calling node */ + error = VOP_LINK(tdvp, vp, cnp); /* call link on upper */ + + /* + * We have to unlock tdvp prior to relocking our calling node in + * order to avoid a deadlock. + */ + union_unlock_upper(tdvp, p); + vn_lock(ap->a_tdvp, LK_EXCLUSIVE | LK_RETRY, p); + return (error); +} + +static 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; + + /* + * Figure out what fdvp to pass to our upper or lower vnode. If we + * replace the fdvp, release the original one and ref the new one. + */ + + 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); + } + + /* + * Figure out what fvp to pass to our upper or lower vnode. If we + * replace the fvp, release the original one and ref the new one. + */ + + if (fvp->v_op == union_vnodeop_p) { /* always true */ + struct union_node *un = VTOUNION(fvp); +#if 0 + struct union_mount *um = MOUNTTOUNIONMOUNT(fvp->v_mount); +#endif + + if (un->un_uppervp == NULLVP) { + switch(fvp->v_type) { + case VREG: + vn_lock(un->un_vnode, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_proc); + error = union_copyup(un, 1, ap->a_fcnp->cn_cred, ap->a_fcnp->cn_proc); + VOP_UNLOCK(un->un_vnode, 0, ap->a_fcnp->cn_proc); + if (error) + goto bad; + break; + case VDIR: + /* + * XXX not yet. + * + * There is only one way to rename a directory + * based in the lowervp, and that is to copy + * the entire directory hierarchy. Otherwise + * it would not last across a reboot. + */ +#if 0 + vrele(fvp); + fvp = NULL; + vn_lock(fdvp, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_proc); + error = union_mkshadow(um, fdvp, + ap->a_fcnp, &un->un_uppervp); + VOP_UNLOCK(fdvp, 0, ap->a_fcnp->cn_proc); + if (un->un_uppervp) + VOP_UNLOCK(un->un_uppervp, 0, ap->a_fcnp->cn_proc); + if (error) + goto bad; + break; +#endif + default: + error = EXDEV; + goto bad; + } + } + + if (un->un_lowervp != NULLVP) + ap->a_fcnp->cn_flags |= DOWHITEOUT; + fvp = un->un_uppervp; + VREF(fvp); + vrele(ap->a_fvp); + } + + /* + * Figure out what tdvp (destination directory) to pass to the + * lower level. If we replace it with uppervp, we need to vput the + * old one. The exclusive lock is transfered to what we will pass + * down in the VOP_RENAME and we replace uppervp with a simple + * reference. + */ + + 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; + } + + /* + * new tdvp is a lock and reference on uppervp, put away + * the old tdvp. + */ + tdvp = union_lock_upper(un, ap->a_tcnp->cn_proc); + vput(ap->a_tdvp); + } + + /* + * Figure out what tvp (destination file) to pass to the + * lower level. + * + * If the uppervp file does not exist put away the (wrong) + * file and change tvp to NULL. + */ + + if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { + struct union_node *un = VTOUNION(tvp); + + tvp = union_lock_upper(un, ap->a_tcnp->cn_proc); + vput(ap->a_tvp); + /* note: tvp may be NULL */ + } + + /* + * VOP_RENAME releases/vputs prior to returning, so we have no + * cleanup to do. + */ + + return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp)); + + /* + * Error. We still have to release / vput the various elements. + */ + +bad: + vrele(fdvp); + if (fvp) + vrele(fvp); + vput(tdvp); + if (tvp != NULLVP) { + if (tvp != tdvp) + vput(tvp); + else + vrele(tvp); + } + return (error); +} + +static 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 *dun = VTOUNION(ap->a_dvp); + struct componentname *cnp = ap->a_cnp; + struct proc *p = cnp->cn_proc; + struct vnode *upperdvp; + int error = EROFS; + + if ((upperdvp = union_lock_upper(dun, p)) != NULLVP) { + struct vnode *vp; + + error = VOP_MKDIR(upperdvp, &vp, cnp, ap->a_vap); + union_unlock_upper(upperdvp, p); + + if (error == 0) { + VOP_UNLOCK(vp, 0, p); + UDEBUG(("ALLOCVP-2 FROM %p REFS %d\n", vp, vp->v_usecount)); + error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, + ap->a_dvp, NULLVP, cnp, vp, NULLVP, 1); + UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount)); + } + } + return (error); +} + +static int +union_rmdir(ap) + struct vop_rmdir_args /* { + struct vnode *a_dvp; + struct vnode *a_vp; + struct componentname *a_cnp; + } */ *ap; +{ + struct union_node *dun = VTOUNION(ap->a_dvp); + struct union_node *un = VTOUNION(ap->a_vp); + struct componentname *cnp = ap->a_cnp; + struct proc *p = cnp->cn_proc; + struct vnode *upperdvp; + struct vnode *uppervp; + int error; + + if ((upperdvp = union_lock_upper(dun, p)) == NULLVP) + panic("union rmdir: null upper vnode"); + + if ((uppervp = union_lock_upper(un, p)) != NULLVP) { + if (union_dowhiteout(un, cnp->cn_cred, p)) + cnp->cn_flags |= DOWHITEOUT; + error = VOP_RMDIR(upperdvp, uppervp, ap->a_cnp); + union_unlock_upper(uppervp, p); + } else { + error = union_mkwhiteout( + MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount), + dun->un_uppervp, ap->a_cnp, un->un_path); + } + union_unlock_upper(upperdvp, p); + return (error); +} + +/* + * union_symlink: + * + * dvp is locked on entry and remains locked on return. a_vpp is garbage + * (unused). + */ + +static 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 *dun = VTOUNION(ap->a_dvp); + struct componentname *cnp = ap->a_cnp; + struct proc *p = cnp->cn_proc; + struct vnode *dvp; + int error = EROFS; + + if ((dvp = union_lock_upper(dun, p)) != NULLVP) { + error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, + ap->a_target); + union_unlock_upper(dvp, p); + } + return (error); +} + +/* + * 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. + */ +static int +union_readdir(ap) + struct vop_readdir_args /* { + struct vnode *a_vp; + struct uio *a_uio; + struct ucred *a_cred; + int *a_eofflag; + u_long *a_cookies; + int a_ncookies; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + struct proc *p = ap->a_uio->uio_procp; + struct vnode *uvp; + int error = 0; + + if ((uvp = union_lock_upper(un, p)) != NULLVP) { + ap->a_vp = uvp; + error = VCALL(uvp, VOFFSET(vop_readdir), ap); + union_unlock_upper(uvp, p); + } + return(error); +} + +static int +union_readlink(ap) + struct vop_readlink_args /* { + struct vnode *a_vp; + struct uio *a_uio; + struct ucred *a_cred; + } */ *ap; +{ + int error; + struct union_node *un = VTOUNION(ap->a_vp); + struct uio *uio = ap->a_uio; + struct proc *p = uio->uio_procp; + struct vnode *vp; + + vp = union_lock_other(un, p); + KASSERT(vp != NULL, ("union_readlink: backing vnode missing!")); + + ap->a_vp = vp; + error = VCALL(vp, VOFFSET(vop_readlink), ap); + union_unlock_other(vp, p); + + return (error); +} + +/* + * union_inactive: + * + * Called with the vnode locked. We are expected to unlock the vnode. + */ + +static int +union_inactive(ap) + struct vop_inactive_args /* { + struct vnode *a_vp; + struct proc *a_p; + } */ *ap; +{ + struct vnode *vp = ap->a_vp; + struct proc *p = ap->a_p; + 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; + } + +#if 0 + if ((un->un_flags & UN_ULOCK) && un->un_uppervp) { + un->un_flags &= ~UN_ULOCK; + VOP_UNLOCK(un->un_uppervp, 0, p); + } +#endif + + VOP_UNLOCK(vp, 0, p); + + if ((un->un_flags & UN_CACHED) == 0) + vgone(vp); + + return (0); +} + +static int +union_reclaim(ap) + struct vop_reclaim_args /* { + struct vnode *a_vp; + } */ *ap; +{ + union_freevp(ap->a_vp); + + return (0); +} + +static int +union_lock(ap) + struct vop_lock_args *ap; +{ +#if 0 + struct vnode *vp = ap->a_vp; + struct proc *p = ap->a_p; + int flags = ap->a_flags; + struct union_node *un; +#endif + int error; + + error = vop_stdlock(ap); +#if 0 + un = VTOUNION(vp); + + if (error == 0) { + /* + * Lock the upper if it exists and this is an exclusive lock + * request. + */ + if (un->un_uppervp != NULLVP && + (flags & LK_TYPE_MASK) == LK_EXCLUSIVE) { + if ((un->un_flags & UN_ULOCK) == 0 && vp->v_usecount) { + error = vn_lock(un->un_uppervp, flags, p); + if (error) { + struct vop_unlock_args uap = { 0 }; + uap.a_vp = ap->a_vp; + uap.a_flags = ap->a_flags; + uap.a_p = ap->a_p; + vop_stdunlock(&uap); + return (error); + } + un->un_flags |= UN_ULOCK; + } + } + } +#endif + return (error); +} + +/* + * union_unlock: + * + * Unlock our union node. This also unlocks uppervp. + */ +static int +union_unlock(ap) + struct vop_unlock_args /* { + struct vnode *a_vp; + int a_flags; + struct proc *a_p; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + int error; + + KASSERT((un->un_uppervp == NULL || un->un_uppervp->v_usecount > 0), ("uppervp usecount is 0")); + + error = vop_stdunlock(ap); +#if 0 + + /* + * If no exclusive locks remain and we are holding an uppervp lock, + * remove the uppervp lock. + */ + + if ((un->un_flags & UN_ULOCK) && + lockstatus(&un->un_lock, NULL) != LK_EXCLUSIVE) { + un->un_flags &= ~UN_ULOCK; + VOP_UNLOCK(un->un_uppervp, LK_EXCLUSIVE, p); + } +#endif + return(error); +} + +/* + * union_bmap: + * + * There isn't much we can do. We cannot push through to the real vnode + * to get to the underlying device because this will bypass data + * cached by the real vnode. + * + * For some reason we cannot return the 'real' vnode either, it seems + * to blow up memory maps. + */ + +static 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; + int *a_runb; + } */ *ap; +{ + return(EOPNOTSUPP); +} + +static int +union_print(ap) + struct vop_print_args /* { + struct vnode *a_vp; + } */ *ap; +{ + 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)); + + return (0); +} + +static int +union_pathconf(ap) + struct vop_pathconf_args /* { + struct vnode *a_vp; + int a_name; + int *a_retval; + } */ *ap; +{ + int error; + struct proc *p = curproc; /* XXX */ + struct union_node *un = VTOUNION(ap->a_vp); + struct vnode *vp; + + vp = union_lock_other(un, p); + KASSERT(vp != NULL, ("union_pathconf: backing vnode missing!")); + + ap->a_vp = vp; + error = VCALL(vp, VOFFSET(vop_pathconf), ap); + union_unlock_other(vp, p); + + return (error); +} + +static 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; +{ + register struct vnode *ovp = OTHERVP(ap->a_vp); + + ap->a_vp = ovp; + return (VCALL(ovp, VOFFSET(vop_advlock), ap)); +} + + +/* + * XXX - vop_strategy must be hand coded because it has no + * YYY - and it is not coherent with anything + * + * vnode in its arguments. + * This goes away with a merged VM/buffer cache. + */ +static int +union_strategy(ap) + struct vop_strategy_args /* { + struct vnode *a_vp; + struct buf *a_bp; + } */ *ap; +{ + struct buf *bp = ap->a_bp; + struct vnode *othervp = OTHERVP(bp->b_vp); + +#ifdef DIAGNOSTIC + if (othervp == NULLVP) + panic("union_strategy: nil vp"); + if (((bp->b_flags & B_READ) == 0) && + (othervp == LOWERVP(bp->b_vp))) + panic("union_strategy: writing to lowervp"); +#endif + return (VOP_STRATEGY(othervp, bp)); +} + +/* + * Global vfs data structures + */ +vop_t **union_vnodeop_p; +static struct vnodeopv_entry_desc union_vnodeop_entries[] = { + { &vop_default_desc, (vop_t *) vop_defaultop }, + { &vop_access_desc, (vop_t *) union_access }, + { &vop_advlock_desc, (vop_t *) union_advlock }, + { &vop_bmap_desc, (vop_t *) union_bmap }, + { &vop_close_desc, (vop_t *) union_close }, + { &vop_create_desc, (vop_t *) union_create }, + { &vop_fsync_desc, (vop_t *) union_fsync }, + { &vop_getpages_desc, (vop_t *) union_getpages }, + { &vop_putpages_desc, (vop_t *) union_putpages }, + { &vop_getattr_desc, (vop_t *) union_getattr }, + { &vop_inactive_desc, (vop_t *) union_inactive }, + { &vop_ioctl_desc, (vop_t *) union_ioctl }, + { &vop_islocked_desc, (vop_t *) vop_stdislocked }, + { &vop_lease_desc, (vop_t *) union_lease }, + { &vop_link_desc, (vop_t *) union_link }, + { &vop_lock_desc, (vop_t *) union_lock }, + { &vop_lookup_desc, (vop_t *) union_lookup }, + { &vop_mkdir_desc, (vop_t *) union_mkdir }, + { &vop_mknod_desc, (vop_t *) union_mknod }, + { &vop_mmap_desc, (vop_t *) union_mmap }, + { &vop_open_desc, (vop_t *) union_open }, + { &vop_pathconf_desc, (vop_t *) union_pathconf }, + { &vop_poll_desc, (vop_t *) union_poll }, + { &vop_print_desc, (vop_t *) union_print }, + { &vop_read_desc, (vop_t *) union_read }, + { &vop_readdir_desc, (vop_t *) union_readdir }, + { &vop_readlink_desc, (vop_t *) union_readlink }, + { &vop_reclaim_desc, (vop_t *) union_reclaim }, + { &vop_remove_desc, (vop_t *) union_remove }, + { &vop_rename_desc, (vop_t *) union_rename }, + { &vop_revoke_desc, (vop_t *) union_revoke }, + { &vop_rmdir_desc, (vop_t *) union_rmdir }, + { &vop_setattr_desc, (vop_t *) union_setattr }, + { &vop_strategy_desc, (vop_t *) union_strategy }, + { &vop_symlink_desc, (vop_t *) union_symlink }, + { &vop_unlock_desc, (vop_t *) union_unlock }, + { &vop_whiteout_desc, (vop_t *) union_whiteout }, + { &vop_write_desc, (vop_t *) union_write }, + { NULL, NULL } +}; +static struct vnodeopv_desc union_vnodeop_opv_desc = + { &union_vnodeop_p, union_vnodeop_entries }; + +VNODEOP_SET(union_vnodeop_opv_desc); |
