/* $OpenBSD: union_vfsops.c,v 1.13 2002/03/14 01:27:08 millert Exp $ */ /* $NetBSD: union_vfsops.c,v 1.10 1995/06/18 14:47:47 cgd Exp $ */ /* * Copyright (c) 1994 The Regents of the University of California. * Copyright (c) 1994 Jan-Simon Pendry. * All rights reserved. * * This code is derived from software donated 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_vfsops.c 8.13 (Berkeley) 12/10/94 */ /* * Union Layer */ #include <sys/param.h> #include <sys/systm.h> #include <sys/time.h> #include <sys/types.h> #include <sys/proc.h> #include <sys/vnode.h> #include <sys/mount.h> #include <sys/namei.h> #include <sys/malloc.h> #include <sys/filedesc.h> #include <sys/queue.h> #include <sys/stat.h> #include <miscfs/union/union.h> int union_mount(struct mount *, const char *, void *, struct nameidata *, struct proc *); int union_start(struct mount *, int, struct proc *); int union_unmount(struct mount *, int, struct proc *); int union_root(struct mount *, struct vnode **); int union_statfs(struct mount *, struct statfs *, struct proc *); /* * Mount union filesystem */ int union_mount(mp, path, data, ndp, p) struct mount *mp; const char *path; void *data; struct nameidata *ndp; struct proc *p; { int error = 0; struct union_args args; struct vnode *lowerrootvp = NULLVP; struct vnode *upperrootvp = NULLVP; struct union_mount *um = 0; struct ucred *cred = 0; char *cp; int len; size_t size; #ifdef UNION_DIAGNOSTIC printf("union_mount(mp = %p)\n", mp); #endif /* * Update is a no-op */ if (mp->mnt_flag & MNT_UPDATE) { /* * Need to provide. * 1. a way to convert between rdonly and rdwr mounts. * 2. support for nfs exports. */ error = EOPNOTSUPP; goto bad; } /* * Get argument */ error = copyin(data, &args, sizeof(struct union_args)); if (error) goto bad; lowerrootvp = mp->mnt_vnodecovered; VREF(lowerrootvp); /* * Find upper node. */ NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT, UIO_USERSPACE, args.target, p); if ((error = namei(ndp)) != 0) goto bad; upperrootvp = ndp->ni_vp; vrele(ndp->ni_dvp); ndp->ni_dvp = NULL; if (upperrootvp->v_type != VDIR) { error = EINVAL; goto bad; } um = (struct union_mount *) malloc(sizeof(struct union_mount), M_UFSMNT, M_WAITOK); /* XXX */ /* * Keep a held reference to the target vnodes. * They are vrele'd in union_unmount. * * Depending on the _BELOW flag, the filesystems are * viewed in a different order. In effect, this is the * same as providing a mount under option to the mount syscall. */ um->um_op = args.mntflags & UNMNT_OPMASK; switch (um->um_op) { case UNMNT_ABOVE: um->um_lowervp = lowerrootvp; um->um_uppervp = upperrootvp; break; case UNMNT_BELOW: um->um_lowervp = upperrootvp; um->um_uppervp = lowerrootvp; break; case UNMNT_REPLACE: vrele(lowerrootvp); lowerrootvp = NULLVP; um->um_uppervp = upperrootvp; um->um_lowervp = lowerrootvp; break; default: error = EINVAL; goto bad; } /* * Unless the mount is readonly, ensure that the top layer * supports whiteout operations */ if ((mp->mnt_flag & MNT_RDONLY) == 0) { error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP); if (error) goto bad; } um->um_cred = p->p_ucred; crhold(um->um_cred); um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask; /* * Depending on what you think the MNT_LOCAL flag might mean, * you may want the && to be || on the conditional below. * At the moment it has been defined that the filesystem is * only local if it is all local, ie the MNT_LOCAL flag implies * that the entire namespace is local. If you think the MNT_LOCAL * flag implies that some of the files might be stored locally * then you will want to change the conditional. */ if (um->um_op == UNMNT_ABOVE) { if (((um->um_lowervp == NULLVP) || (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) mp->mnt_flag |= MNT_LOCAL; } /* * Copy in the upper layer's RDONLY flag. This is for the benefit * of lookup() which explicitly checks the flag, rather than asking * the filesystem for it's own opinion. This means, that an update * mount of the underlying filesystem to go from rdonly to rdwr * will leave the unioned view as read-only. */ mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); mp->mnt_data = (qaddr_t)um; vfs_getnewfsid(mp); (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); switch (um->um_op) { case UNMNT_ABOVE: cp = "<above>:"; break; case UNMNT_BELOW: cp = "<below>:"; break; case UNMNT_REPLACE: cp = ""; break; default: cp = "<invalid>:"; #ifdef DIAGNOSTIC panic("union_mount: bad um_op"); #endif break; } len = strlen(cp); bcopy(cp, mp->mnt_stat.f_mntfromname, len); cp = mp->mnt_stat.f_mntfromname + len; len = MNAMELEN - len; (void) copyinstr(args.target, cp, len - 1, &size); bzero(cp + size, len - size); #ifdef UNION_DIAGNOSTIC printf("union_mount: from %s, on %s\n", mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); #endif return (0); bad: if (um) free(um, M_UFSMNT); if (cred) crfree(cred); if (upperrootvp) vrele(upperrootvp); if (lowerrootvp) vrele(lowerrootvp); return (error); } /* * VFS start. Nothing needed here - the start routine * on the underlying filesystem(s) will have been called * when that filesystem was mounted. */ /*ARGSUSED*/ int union_start(mp, flags, p) struct mount *mp; int flags; struct proc *p; { return (0); } int union_unmount_count_vnode(struct vnode *vp, void *args); int union_unmount_count_vnode(struct vnode *vp, void *args) { int *n = args; *n = *n + 1; simple_unlock(&vp->v_interlock); return (0); } /* * Free reference to union layer */ int union_unmount(mp, mntflags, p) struct mount *mp; int mntflags; struct proc *p; { struct union_mount *um = MOUNTTOUNIONMOUNT(mp); struct vnode *um_rootvp; int error; int freeing; int flags = 0; #ifdef UNION_DIAGNOSTIC printf("union_unmount(mp = %p)\n", mp); #endif if (mntflags & MNT_FORCE) { flags |= FORCECLOSE; } if ((error = union_root(mp, &um_rootvp)) != 0) return (error); /* * Keep flushing vnodes from the mount list. * This is needed because of the un_pvp held * reference to the parent vnode. * If more vnodes have been freed on a given pass, * the try again. The loop will iterate at most * (d) times, where (d) is the maximum tree depth * in the filesystem. */ for (freeing = 0; vflush(mp, um_rootvp, flags) != 0;) { int n; /* count #vnodes held on mount list */ vfs_mount_foreach_vnode(mp, union_unmount_count_vnode, &n); /* if this is unchanged then stop */ if (n == freeing) break; /* otherwise try once more time */ freeing = n; } /* At this point the root vnode should have a single reference */ if (um_rootvp->v_usecount > 1) { vput(um_rootvp); return (EBUSY); } #ifdef UNION_DIAGNOSTIC vprint("union root", um_rootvp); #endif /* * Discard references to upper and lower target vnodes. */ if (um->um_lowervp) vrele(um->um_lowervp); vrele(um->um_uppervp); crfree(um->um_cred); /* * Release reference on underlying root vnode */ vput(um_rootvp); /* * And blow it away for future re-use */ vgone(um_rootvp); /* * Finally, throw away the union_mount structure */ free(mp->mnt_data, M_UFSMNT); /* XXX */ mp->mnt_data = 0; return (0); } int union_root(mp, vpp) struct mount *mp; struct vnode **vpp; { struct proc *p = curproc; struct union_mount *um = MOUNTTOUNIONMOUNT(mp); int error; int loselock; /* * Return locked reference to root. */ VREF(um->um_uppervp); if ((um->um_op == UNMNT_BELOW) && VOP_ISLOCKED(um->um_uppervp)) { loselock = 1; } else { vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY, p); loselock = 0; } if (um->um_lowervp) VREF(um->um_lowervp); error = union_allocvp(vpp, mp, (struct vnode *) 0, (struct vnode *) 0, (struct componentname *) 0, um->um_uppervp, um->um_lowervp, 1); if (error) { if (loselock) vrele(um->um_uppervp); else vput(um->um_uppervp); if (um->um_lowervp) vrele(um->um_lowervp); } else { if (loselock) VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; } return (error); } int union_statfs(mp, sbp, p) struct mount *mp; struct statfs *sbp; struct proc *p; { int error; struct union_mount *um = MOUNTTOUNIONMOUNT(mp); struct statfs mstat; int lbsize; #ifdef UNION_DIAGNOSTIC printf("union_statfs(mp = %p, lvp = %p, uvp = %p)\n", mp, um->um_lowervp, um->um_uppervp); #endif bzero(&mstat, sizeof(mstat)); if (um->um_lowervp) { error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p); if (error) return (error); } /* now copy across the "interesting" information and fake the rest */ #if 0 sbp->f_flags = mstat.f_flags; sbp->f_bsize = mstat.f_bsize; sbp->f_iosize = mstat.f_iosize; #endif lbsize = mstat.f_bsize; sbp->f_blocks = mstat.f_blocks; sbp->f_bfree = mstat.f_bfree; sbp->f_bavail = mstat.f_bavail; sbp->f_files = mstat.f_files; sbp->f_ffree = mstat.f_ffree; error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p); if (error) return (error); sbp->f_flags = mstat.f_flags; sbp->f_bsize = mstat.f_bsize; sbp->f_iosize = mstat.f_iosize; /* * if the lower and upper blocksizes differ, then frig the * block counts so that the sizes reported by df make some * kind of sense. none of this makes sense though. */ if (mstat.f_bsize != lbsize) { sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize; sbp->f_bfree = sbp->f_bfree * lbsize / mstat.f_bsize; sbp->f_bavail = sbp->f_bavail * lbsize / mstat.f_bsize; } sbp->f_blocks += mstat.f_blocks; sbp->f_bfree += mstat.f_bfree; sbp->f_bavail += mstat.f_bavail; sbp->f_files += mstat.f_files; sbp->f_ffree += mstat.f_ffree; if (sbp != &mp->mnt_stat) { bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); } strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN); return (0); } #define union_sync ((int (*)(struct mount *, int, struct ucred *, \ struct proc *))nullop) #define union_fhtovp ((int (*)(struct mount *, struct fid *, \ struct vnode **))eopnotsupp) #define union_quotactl ((int (*)(struct mount *, int, uid_t, caddr_t, \ struct proc *))eopnotsupp) #define union_sysctl ((int (*)(int *, u_int, void *, size_t *, void *, \ size_t, struct proc *))eopnotsupp) #define union_vget ((int (*)(struct mount *, ino_t, struct vnode **)) \ eopnotsupp) #define union_vptofh ((int (*)(struct vnode *, struct fid *))eopnotsupp) #define union_checkexp ((int (*)(struct mount *, struct mbuf *, \ int *, struct ucred **))eopnotsupp) struct vfsops union_vfsops = { union_mount, union_start, union_unmount, union_root, union_quotactl, union_statfs, union_sync, union_vget, union_fhtovp, union_vptofh, union_init, union_sysctl, union_checkexp };