/* * Copyright (c) 1994, 1995 The Regents of the University of California. * Copyright (c) 1994, 1995 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 8.20 (Berkeley) 5/20/95 * $Id: union_vfsops.c,v 1.19 1997/08/16 19:15:22 wollman Exp $ */ /* * Union Layer */ #include #include #include #include #include #include #include #include #include #include extern int union_init __P((struct vfsconf *)); extern int union_fhtovp __P((struct mount *mp, struct fid *fidp, struct mbuf *nam, struct vnode **vpp, int *exflagsp, struct ucred **credanonp)); extern int union_mount __P((struct mount *mp, char *path, caddr_t data, struct nameidata *ndp, struct proc *p)); extern int union_quotactl __P((struct mount *mp, int cmd, uid_t uid, caddr_t arg, struct proc *p)); extern int union_root __P((struct mount *mp, struct vnode **vpp)); extern int union_start __P((struct mount *mp, int flags, struct proc *p)); extern int union_statfs __P((struct mount *mp, struct statfs *sbp, struct proc *p)); extern int union_sync __P((struct mount *mp, int waitfor, struct ucred *cred, struct proc *p)); extern int union_unmount __P((struct mount *mp, int mntflags, struct proc *p)); extern int union_vget __P((struct mount *mp, ino_t ino, struct vnode **vpp)); extern int union_vptofh __P((struct vnode *vp, struct fid *fhp)); /* * Mount union filesystem */ int union_mount(mp, path, data, ndp, p) struct mount *mp; char *path; caddr_t 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; struct ucred *scred; struct vattr va; char *cp = 0; int len; u_int size; int islowerunlocked = 0; #ifdef UNION_DIAGNOSTIC printf("union_mount(mp = %x)\n", mp); #endif /* * Disable clustered write, otherwise system becomes unstable. */ mp->mnt_flag |= MNT_NOCLUSTERW; /* * 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, (caddr_t)&args, sizeof(struct union_args)); if (error) goto bad; lowerrootvp = mp->mnt_vnodecovered; VREF(lowerrootvp); /* * Unlock lower node to avoid deadlock. * (XXX) VOP_ISLOCKED is needed? */ if ((lowerrootvp->v_op == union_vnodeop_p) && VOP_ISLOCKED(lowerrootvp)) { VOP_UNLOCK(lowerrootvp, 0, p); islowerunlocked = 1; } /* * Find upper node. */ NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT, UIO_USERSPACE, args.target, p); error = namei(ndp); /* * Re-lock vnode. * (XXX) VOP_ISLOCKED is needed? */ if (islowerunlocked && !VOP_ISLOCKED(lowerrootvp)) vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY, p); if (error) goto bad; upperrootvp = ndp->ni_vp; vrele(ndp->ni_dvp); ndp->ni_dvp = NULL; /* * Check multi union mount to avoid `lock myself again' panic. */ if (upperrootvp == VTOUNION(lowerrootvp)->un_uppervp) { #ifdef DIAGNOSTIC printf("union_mount: multi union mount?\n"); #endif error = EDEADLK; goto bad; } 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 = ":"; break; case UNMNT_BELOW: cp = ":"; break; case UNMNT_REPLACE: cp = ""; 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); (void)union_statfs(mp, &mp->mnt_stat, p); #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. */ int union_start(mp, flags, p) struct mount *mp; int flags; struct proc *p; { 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 = %x)\n", mp); #endif if (mntflags & MNT_FORCE) flags |= FORCECLOSE; if (error = union_root(mp, &um_rootvp)) 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;) { struct vnode *vp; int n; /* count #vnodes held on mount list */ for (n = 0, vp = mp->mnt_vnodelist.lh_first; vp != NULLVP; vp = vp->v_mntvnodes.le_next) 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; /* XXX */ 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 { if (VOP_ISLOCKED(um->um_uppervp)) { /* * XXX * Should we check type of node? */ #ifdef DIAGNOSTIC printf("union_root: multi union mount?"); #endif vrele(um->um_uppervp); return EDEADLK; } 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 = %x, lvp = %x, uvp = %x)\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_type = mstat.f_type; 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 = ((off_t) sbp->f_blocks * lbsize) / mstat.f_bsize; /* * The "total" fields count total resources in all layers, * the "free" fields count only those resources which are * free in the upper layer (since only the upper layer * is writeable). */ 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) { sbp->f_type = mp->mnt_vfc->vfc_typenum; 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); } return (0); } /* * XXX - Assumes no data cached at union layer. */ #define union_sync ((int (*) __P((struct mount *, int, struct ucred *, \ struct proc *)))nullop) #define union_fhtovp ((int (*) __P((struct mount *, struct fid *, \ struct sockaddr *, struct vnode **, int *, struct ucred **)))eopnotsupp) #define union_quotactl ((int (*) __P((struct mount *, int, uid_t, caddr_t, \ struct proc *)))eopnotsupp) #define union_sysctl ((int (*) __P((int *, u_int, void *, size_t *, void *, \ size_t, struct proc *)))eopnotsupp) #define union_vget ((int (*) __P((struct mount *, ino_t, struct vnode **))) \ eopnotsupp) #define union_vptofh ((int (*) __P((struct vnode *, struct fid *)))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, }; VFS_SET(union_vfsops, union, MOUNT_UNION, VFCF_LOOPBACK);