| 1 | /* |
| 2 | * Copyright (c) 1994 The Regents of the University of California. |
| 3 | * Copyright (c) 1994 Jan-Simon Pendry. |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * This code is derived from software donated to Berkeley by |
| 7 | * Jan-Simon Pendry. |
| 8 | * |
| 9 | * %sccs.include.redist.c% |
| 10 | * |
| 11 | * @(#)union_vfsops.c 1.6 (Berkeley) %G% |
| 12 | */ |
| 13 | |
| 14 | /* |
| 15 | * Union Layer |
| 16 | */ |
| 17 | |
| 18 | #include <sys/param.h> |
| 19 | #include <sys/systm.h> |
| 20 | #include <sys/time.h> |
| 21 | #include <sys/types.h> |
| 22 | #include <sys/proc.h> |
| 23 | #include <sys/vnode.h> |
| 24 | #include <sys/mount.h> |
| 25 | #include <sys/namei.h> |
| 26 | #include <sys/malloc.h> |
| 27 | #include <sys/filedesc.h> |
| 28 | #include "union.h" |
| 29 | |
| 30 | /* |
| 31 | * Mount union filesystem |
| 32 | */ |
| 33 | int |
| 34 | union_mount(mp, path, data, ndp, p) |
| 35 | struct mount *mp; |
| 36 | char *path; |
| 37 | caddr_t data; |
| 38 | struct nameidata *ndp; |
| 39 | struct proc *p; |
| 40 | { |
| 41 | int error = 0; |
| 42 | struct union_args args; |
| 43 | struct vnode *lowerrootvp; |
| 44 | struct vnode *upperrootvp; |
| 45 | struct union_mount *um; |
| 46 | u_int size; |
| 47 | |
| 48 | #ifdef UNION_DIAGNOSTIC |
| 49 | printf("union_mount(mp = %x)\n", mp); |
| 50 | #endif |
| 51 | |
| 52 | /* |
| 53 | * Update is a no-op |
| 54 | */ |
| 55 | if (mp->mnt_flag & MNT_UPDATE) { |
| 56 | /* |
| 57 | * Need to provide. |
| 58 | * 1. a way to convert between rdonly and rdwr mounts. |
| 59 | * 2. support for nfs exports. |
| 60 | */ |
| 61 | return (EOPNOTSUPP); |
| 62 | } |
| 63 | |
| 64 | /* |
| 65 | * Get argument |
| 66 | */ |
| 67 | if (error = copyin(data, (caddr_t)&args, sizeof(struct union_args))) |
| 68 | return (error); |
| 69 | |
| 70 | lowerrootvp = mp->mnt_vnodecovered; |
| 71 | VREF(lowerrootvp); |
| 72 | |
| 73 | /* |
| 74 | * Find upper node |
| 75 | */ |
| 76 | NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT, |
| 77 | UIO_USERSPACE, args.target, p); |
| 78 | if (error = namei(ndp)) { |
| 79 | vrele(lowerrootvp); |
| 80 | return (error); |
| 81 | } |
| 82 | upperrootvp = ndp->ni_vp; |
| 83 | vrele(ndp->ni_dvp); |
| 84 | ndp->ni_dvp = NULL; |
| 85 | |
| 86 | if (upperrootvp->v_type != VDIR) { |
| 87 | vrele(lowerrootvp); |
| 88 | vrele(upperrootvp); |
| 89 | return (EINVAL); |
| 90 | } |
| 91 | |
| 92 | um = (struct union_mount *) malloc(sizeof(struct union_mount), |
| 93 | M_UFSMNT, M_WAITOK); /* XXX */ |
| 94 | |
| 95 | /* |
| 96 | * Keep a held reference to the target vnodes. |
| 97 | * They are vrele'd in union_unmount. |
| 98 | */ |
| 99 | um->um_lowervp = lowerrootvp; |
| 100 | um->um_uppervp = upperrootvp; |
| 101 | /* |
| 102 | * Take a copy of the process's credentials. This isn't |
| 103 | * quite right since the euid will always be zero and we |
| 104 | * want to get the "real" users credentials. So fix up |
| 105 | * the uid field after taking the copy. |
| 106 | */ |
| 107 | um->um_cred = crdup(p->p_ucred); |
| 108 | um->um_cred->cr_uid = p->p_cred->p_ruid; |
| 109 | um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask; |
| 110 | |
| 111 | /* |
| 112 | * Depending on what you think the MNT_LOCAL flag might mean, |
| 113 | * you may want the && to be || on the conditional below. |
| 114 | * At the moment it has been defined that the filesystem is |
| 115 | * only local if it is all local, ie the MNT_LOCAL flag implies |
| 116 | * that the entire namespace is local. If you think the MNT_LOCAL |
| 117 | * flag implies that some of the files might be stored locally |
| 118 | * then you will want to change the conditional. |
| 119 | */ |
| 120 | if ((lowerrootvp->v_mount->mnt_flag & MNT_LOCAL) && |
| 121 | (upperrootvp->v_mount->mnt_flag & MNT_LOCAL)) |
| 122 | mp->mnt_flag |= MNT_LOCAL; |
| 123 | |
| 124 | /* |
| 125 | * Copy in the upper layer's RDONLY flag. This is for the benefit |
| 126 | * of lookup() which explicitly checks the flag, rather than asking |
| 127 | * the filesystem for it's own opinion. This means, that an update |
| 128 | * mount of the underlying filesystem to go from rdonly to rdwr |
| 129 | * will leave the unioned view as read-only. |
| 130 | */ |
| 131 | mp->mnt_flag |= (upperrootvp->v_mount->mnt_flag & MNT_RDONLY); |
| 132 | mp->mnt_data = (qaddr_t) um; |
| 133 | getnewfsid(mp, MOUNT_UNION); |
| 134 | |
| 135 | (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); |
| 136 | bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); |
| 137 | bcopy("union:", mp->mnt_stat.f_mntfromname, 6); |
| 138 | (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname + 6, |
| 139 | MNAMELEN - 1 - 6, &size); |
| 140 | bzero(mp->mnt_stat.f_mntfromname + 6 + size, MNAMELEN - 6 - size); |
| 141 | #ifdef UNION_DIAGNOSTIC |
| 142 | printf("union_mount: upper %s, lower at %s\n", |
| 143 | mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); |
| 144 | #endif |
| 145 | return (0); |
| 146 | } |
| 147 | |
| 148 | /* |
| 149 | * VFS start. Nothing needed here - the start routine |
| 150 | * on the underlying filesystem(s) will have been called |
| 151 | * when that filesystem was mounted. |
| 152 | */ |
| 153 | int |
| 154 | union_start(mp, flags, p) |
| 155 | struct mount *mp; |
| 156 | int flags; |
| 157 | struct proc *p; |
| 158 | { |
| 159 | |
| 160 | return (0); |
| 161 | } |
| 162 | |
| 163 | /* |
| 164 | * Free reference to union layer |
| 165 | */ |
| 166 | int |
| 167 | union_unmount(mp, mntflags, p) |
| 168 | struct mount *mp; |
| 169 | int mntflags; |
| 170 | struct proc *p; |
| 171 | { |
| 172 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 173 | struct vnode *um_rootvp; |
| 174 | int error; |
| 175 | int flags = 0; |
| 176 | extern int doforce; |
| 177 | |
| 178 | #ifdef UNION_DIAGNOSTIC |
| 179 | printf("union_unmount(mp = %x)\n", mp); |
| 180 | #endif |
| 181 | |
| 182 | if (mntflags & MNT_FORCE) { |
| 183 | /* union can never be rootfs so don't check for it */ |
| 184 | if (!doforce) |
| 185 | return (EINVAL); |
| 186 | flags |= FORCECLOSE; |
| 187 | } |
| 188 | |
| 189 | if (error = union_root(mp, &um_rootvp)) |
| 190 | return (error); |
| 191 | if (um_rootvp->v_usecount > 1) { |
| 192 | vput(um_rootvp); |
| 193 | return (EBUSY); |
| 194 | } |
| 195 | if (error = vflush(mp, um_rootvp, flags)) { |
| 196 | vput(um_rootvp); |
| 197 | return (error); |
| 198 | } |
| 199 | |
| 200 | #ifdef UNION_DIAGNOSTIC |
| 201 | vprint("alias root of lower", um_rootvp); |
| 202 | #endif |
| 203 | /* |
| 204 | * Discard references to upper and lower target vnodes. |
| 205 | */ |
| 206 | vrele(um->um_lowervp); |
| 207 | vrele(um->um_uppervp); |
| 208 | crfree(um->um_cred); |
| 209 | /* |
| 210 | * Release reference on underlying root vnode |
| 211 | */ |
| 212 | vput(um_rootvp); |
| 213 | /* |
| 214 | * And blow it away for future re-use |
| 215 | */ |
| 216 | vgone(um_rootvp); |
| 217 | /* |
| 218 | * Finally, throw away the union_mount structure |
| 219 | */ |
| 220 | free(mp->mnt_data, M_UFSMNT); /* XXX */ |
| 221 | mp->mnt_data = 0; |
| 222 | return (0); |
| 223 | } |
| 224 | |
| 225 | int |
| 226 | union_root(mp, vpp) |
| 227 | struct mount *mp; |
| 228 | struct vnode **vpp; |
| 229 | { |
| 230 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 231 | int error; |
| 232 | |
| 233 | #ifdef UNION_DIAGNOSTIC |
| 234 | printf("union_root(mp = %x, lvp = %x, uvp = %x)\n", mp, |
| 235 | um->um_lowervp, |
| 236 | um->um_uppervp); |
| 237 | #endif |
| 238 | |
| 239 | /* |
| 240 | * Return locked reference to root. |
| 241 | */ |
| 242 | VREF(um->um_uppervp); |
| 243 | VREF(um->um_lowervp); |
| 244 | error = union_allocvp(vpp, mp, |
| 245 | (struct vnode *) 0, |
| 246 | (struct vnode *) 0, |
| 247 | (struct componentname *) 0, |
| 248 | um->um_uppervp, |
| 249 | um->um_lowervp); |
| 250 | |
| 251 | if (error) { |
| 252 | vrele(um->um_uppervp); |
| 253 | vrele(um->um_lowervp); |
| 254 | } else { |
| 255 | (*vpp)->v_flag |= VROOT; |
| 256 | } |
| 257 | |
| 258 | return (error); |
| 259 | } |
| 260 | |
| 261 | int |
| 262 | union_quotactl(mp, cmd, uid, arg, p) |
| 263 | struct mount *mp; |
| 264 | int cmd; |
| 265 | uid_t uid; |
| 266 | caddr_t arg; |
| 267 | struct proc *p; |
| 268 | { |
| 269 | |
| 270 | return (EOPNOTSUPP); |
| 271 | } |
| 272 | |
| 273 | int |
| 274 | union_statfs(mp, sbp, p) |
| 275 | struct mount *mp; |
| 276 | struct statfs *sbp; |
| 277 | struct proc *p; |
| 278 | { |
| 279 | int error; |
| 280 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 281 | struct statfs mstat; |
| 282 | int lbsize; |
| 283 | |
| 284 | #ifdef UNION_DIAGNOSTIC |
| 285 | printf("union_statfs(mp = %x, lvp = %x, uvp = %x)\n", mp, |
| 286 | um->um_lowervp, |
| 287 | um->um_uppervp); |
| 288 | #endif |
| 289 | |
| 290 | bzero(&mstat, sizeof(mstat)); |
| 291 | |
| 292 | error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p); |
| 293 | if (error) |
| 294 | return (error); |
| 295 | |
| 296 | /* now copy across the "interesting" information and fake the rest */ |
| 297 | #if 0 |
| 298 | sbp->f_type = mstat.f_type; |
| 299 | sbp->f_flags = mstat.f_flags; |
| 300 | sbp->f_bsize = mstat.f_bsize; |
| 301 | sbp->f_iosize = mstat.f_iosize; |
| 302 | #endif |
| 303 | lbsize = mstat.f_bsize; |
| 304 | sbp->f_blocks = mstat.f_blocks; |
| 305 | sbp->f_bfree = mstat.f_bfree; |
| 306 | sbp->f_bavail = mstat.f_bavail; |
| 307 | sbp->f_files = mstat.f_files; |
| 308 | sbp->f_ffree = mstat.f_ffree; |
| 309 | |
| 310 | error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p); |
| 311 | if (error) |
| 312 | return (error); |
| 313 | |
| 314 | sbp->f_type = mstat.f_type; |
| 315 | sbp->f_flags = mstat.f_flags; |
| 316 | sbp->f_bsize = mstat.f_bsize; |
| 317 | sbp->f_iosize = mstat.f_iosize; |
| 318 | |
| 319 | /* |
| 320 | * if the lower and upper blocksizes differ, then frig the |
| 321 | * block counts so that the sizes reported by df make some |
| 322 | * kind of sense. none of this makes sense though. |
| 323 | */ |
| 324 | |
| 325 | if (mstat.f_bsize != lbsize) { |
| 326 | sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize; |
| 327 | sbp->f_bfree = sbp->f_bfree * lbsize / mstat.f_bsize; |
| 328 | sbp->f_bavail = sbp->f_bavail * lbsize / mstat.f_bsize; |
| 329 | } |
| 330 | sbp->f_blocks += mstat.f_blocks; |
| 331 | sbp->f_bfree += mstat.f_bfree; |
| 332 | sbp->f_bavail += mstat.f_bavail; |
| 333 | sbp->f_files += mstat.f_files; |
| 334 | sbp->f_ffree += mstat.f_ffree; |
| 335 | |
| 336 | if (sbp != &mp->mnt_stat) { |
| 337 | bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); |
| 338 | bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); |
| 339 | bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); |
| 340 | } |
| 341 | return (0); |
| 342 | } |
| 343 | |
| 344 | int |
| 345 | union_sync(mp, waitfor, cred, p) |
| 346 | struct mount *mp; |
| 347 | int waitfor; |
| 348 | struct ucred *cred; |
| 349 | struct proc *p; |
| 350 | { |
| 351 | |
| 352 | /* |
| 353 | * XXX - Assumes no data cached at union layer. |
| 354 | */ |
| 355 | return (0); |
| 356 | } |
| 357 | |
| 358 | int |
| 359 | union_vget(mp, ino, vpp) |
| 360 | struct mount *mp; |
| 361 | ino_t ino; |
| 362 | struct vnode **vpp; |
| 363 | { |
| 364 | |
| 365 | return (EOPNOTSUPP); |
| 366 | } |
| 367 | |
| 368 | int |
| 369 | union_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp) |
| 370 | struct mount *mp; |
| 371 | struct fid *fidp; |
| 372 | struct mbuf *nam; |
| 373 | struct vnode **vpp; |
| 374 | int *exflagsp; |
| 375 | struct ucred **credanonp; |
| 376 | { |
| 377 | |
| 378 | return (EOPNOTSUPP); |
| 379 | } |
| 380 | |
| 381 | int |
| 382 | union_vptofh(vp, fhp) |
| 383 | struct vnode *vp; |
| 384 | struct fid *fhp; |
| 385 | { |
| 386 | |
| 387 | return (EOPNOTSUPP); |
| 388 | } |
| 389 | |
| 390 | int union_init __P((void)); |
| 391 | |
| 392 | struct vfsops union_vfsops = { |
| 393 | union_mount, |
| 394 | union_start, |
| 395 | union_unmount, |
| 396 | union_root, |
| 397 | union_quotactl, |
| 398 | union_statfs, |
| 399 | union_sync, |
| 400 | union_vget, |
| 401 | union_fhtovp, |
| 402 | union_vptofh, |
| 403 | union_init, |
| 404 | }; |