1 /* 2 * Copyright (c) 1992, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software donated to Berkeley by 6 * Jan-Simon Pendry. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 37 * 38 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 39 * $FreeBSD: src/sys/miscfs/nullfs/null_vfsops.c,v 1.35.2.3 2001/07/26 20:37:11 iedowse Exp $ 40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.31 2008/09/17 21:44:25 dillon Exp $ 41 */ 42 43 /* 44 * Null Layer 45 * (See null_vnops.c for a description of what this does.) 46 */ 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/kernel.h> 51 #include <sys/proc.h> 52 #include <sys/malloc.h> 53 #include <sys/vnode.h> 54 #include <sys/mount.h> 55 #include <sys/namecache.h> 56 #include <sys/nlookup.h> 57 #include <sys/mountctl.h> 58 #include "null.h" 59 60 extern struct vop_ops null_vnode_vops; 61 62 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 63 64 static int nullfs_root(struct mount *mp, struct vnode **vpp); 65 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 66 struct ucred *cred); 67 68 /* 69 * Mount null layer 70 */ 71 static int 72 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred) 73 { 74 int error = 0; 75 struct null_args args; 76 struct vnode *rootvp; 77 struct null_mount *xmp; 78 size_t size; 79 struct nlookupdata nd; 80 fhandle_t fh; 81 82 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 83 84 /* 85 * Get argument 86 */ 87 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 88 if (error) 89 return (error); 90 91 /* 92 * XXX: Should we process mount export info ? 93 * If not, returning zero here is enough as the actual ro/rw update is 94 * being done in sys_mount(). 95 */ 96 if (mp->mnt_flag & MNT_UPDATE) { 97 xmp = MOUNTTONULLMOUNT(mp); 98 error = vfs_export(mp, &xmp->export, &args.export); 99 return (error); 100 } 101 102 /* 103 * Find lower node 104 */ 105 rootvp = NULL; 106 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW); 107 if (error) 108 goto fail1; 109 error = nlookup(&nd); 110 if (error) 111 goto fail2; 112 error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &rootvp); 113 if (error) 114 goto fail2; 115 116 xmp = (struct null_mount *) kmalloc(sizeof(struct null_mount), 117 M_NULLFSMNT, M_WAITOK | M_ZERO); 118 119 /* 120 * Save reference to underlying FS 121 * 122 * As lite stacking enters the scene, the old way of doing this 123 * -- via the vnode -- is not good enough anymore. Use the 124 * underlying filesystem's namecache handle as our mount point 125 * root, adjusting the mount to point to us. 126 * 127 * NCF_ISMOUNTPT is normally set on the mount point, but we also 128 * want to set it on the base directory being mounted to prevent 129 * that directory from being destroyed out from under the nullfs 130 * mount. 131 * 132 * The forwarding mount pointer (xmp->nullm_vfs) must be set to 133 * the actual target filesystem. If the target filesystem was 134 * resolved via a nullfs mount nd.nl_nch.mount will be pointing 135 * to the nullfs mount structure instead of the target filesystem, 136 * which would otherwise cause the mount VOPS and VFSOPS to recurse 137 * endlessly. If we are mounting via a nullfs mount we inherit 138 * its read-only state, if set. 139 */ 140 xmp->nullm_vfs = nd.nl_nch.mount; 141 if (xmp->nullm_vfs != rootvp->v_mount) { 142 if (xmp->nullm_vfs->mnt_flag & MNT_RDONLY) 143 mp->mnt_flag |= MNT_RDONLY; 144 if (xmp->nullm_vfs->mnt_flag & MNT_NOEXEC) 145 mp->mnt_flag |= MNT_NOEXEC; 146 xmp->nullm_vfs = rootvp->v_mount; 147 } 148 149 /* 150 * ncmountpt is the parent glue. When mounting a nullfs via a nullfs 151 * we retain the parent nullfs to create a unique chain tuple. 152 */ 153 mp->mnt_ncmountpt = nd.nl_nch; 154 cache_changemount(&mp->mnt_ncmountpt, mp); 155 mp->mnt_ncmountpt.ncp->nc_flag |= NCF_ISMOUNTPT; 156 cache_unlock(&mp->mnt_ncmountpt); 157 cache_zero(&nd.nl_nch); 158 nlookup_done(&nd); 159 160 vfs_add_vnodeops(mp, &null_vnode_vops, &mp->mnt_vn_norm_ops); 161 162 vn_unlock(rootvp); /* leave reference intact */ 163 164 /* 165 * Keep a held reference to the root vnode. 166 * It is vrele'd in nullfs_unmount. 167 */ 168 xmp->nullm_rootvp = rootvp; 169 /* 170 * XXX What's the proper safety condition for querying 171 * the underlying mount? Is this flag tuning necessary 172 * at all? 173 */ 174 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL) 175 mp->mnt_flag |= MNT_LOCAL; 176 mp->mnt_data = (qaddr_t) xmp; 177 178 /* 179 * Try to create a unique but non-random fsid for the nullfs to 180 * allow it to be exported via NFS. 181 */ 182 bzero(&fh, sizeof(fh)); 183 fh.fh_fsid = rootvp->v_mount->mnt_stat.f_fsid; 184 if (VFS_VPTOFH(rootvp, &fh.fh_fid) == 0) { 185 fh.fh_fsid.val[1] ^= crc32(&fh.fh_fid, sizeof(fh.fh_fid)); 186 vfs_setfsid(mp, &fh.fh_fsid); 187 } else { 188 vfs_getnewfsid(mp); 189 } 190 191 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 192 &size); 193 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 194 (void)nullfs_statfs(mp, &mp->mnt_stat, cred); 195 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 196 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname); 197 198 bzero(mp->mnt_stat.f_mntonname, MNAMELEN); 199 if (path != NULL) { 200 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, 201 &size); 202 } 203 204 /* 205 * Set NCALIASED so unmount won't complain about namecache refs 206 * still existing. 207 * 208 * All NULLFS operations are MPSAFE, though it will be short-lived 209 * if the underlying filesystem is not. 210 */ 211 mp->mnt_kern_flag |= MNTK_NCALIASED | MNTK_ALL_MPSAFE; 212 return (0); 213 fail2: 214 nlookup_done(&nd); 215 fail1: 216 return (error); 217 } 218 219 /* 220 * Free reference to null layer 221 */ 222 static int 223 nullfs_unmount(struct mount *mp, int mntflags) 224 { 225 struct null_mount *xmp; 226 227 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 228 229 /* 230 * Throw away the null_mount structure 231 */ 232 xmp = (void *)mp->mnt_data; 233 mp->mnt_data = 0; 234 if (xmp->nullm_rootvp) { 235 vrele(xmp->nullm_rootvp); 236 xmp->nullm_rootvp = NULL; 237 } 238 kfree(xmp, M_NULLFSMNT); 239 return 0; 240 } 241 242 static int 243 nullfs_root(struct mount *mp, struct vnode **vpp) 244 { 245 struct vnode *vp; 246 int error; 247 248 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp, 249 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp); 250 251 /* 252 * Return locked reference to root. 253 */ 254 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 255 error = vget(vp, LK_EXCLUSIVE | LK_RETRY); 256 if (error == 0) 257 *vpp = vp; 258 return (error); 259 } 260 261 static int 262 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 263 struct ucred *cred) 264 { 265 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, cred); 266 } 267 268 static int 269 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred) 270 { 271 int error; 272 struct statfs mstat; 273 274 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp, 275 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp); 276 277 bzero(&mstat, sizeof(mstat)); 278 279 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, cred); 280 if (error) 281 return (error); 282 283 /* now copy across the "interesting" information and fake the rest */ 284 sbp->f_type = mstat.f_type; 285 sbp->f_flags = mstat.f_flags; 286 sbp->f_bsize = mstat.f_bsize; 287 sbp->f_iosize = mstat.f_iosize; 288 sbp->f_blocks = mstat.f_blocks; 289 sbp->f_bfree = mstat.f_bfree; 290 sbp->f_bavail = mstat.f_bavail; 291 sbp->f_files = mstat.f_files; 292 sbp->f_ffree = mstat.f_ffree; 293 if (sbp != &mp->mnt_stat) { 294 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 295 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 296 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 297 } 298 return (0); 299 } 300 301 /* 302 * Implement NFS export tracking 303 */ 304 static int 305 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 306 struct ucred **credanonp) 307 { 308 struct null_mount *xmp = (void *)mp->mnt_data; 309 struct netcred *np; 310 int error; 311 312 np = vfs_export_lookup(mp, &xmp->export, nam); 313 if (np) { 314 *extflagsp = np->netc_exflags; 315 *credanonp = &np->netc_anon; 316 error = 0; 317 } else { 318 error = EACCES; 319 } 320 return(error); 321 #if 0 322 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 323 extflagsp, credanonp); 324 #endif 325 } 326 327 int 328 nullfs_export(struct mount *mp, int op, const struct export_args *export) 329 { 330 struct null_mount *xmp = (void *)mp->mnt_data; 331 int error; 332 333 switch(op) { 334 case MOUNTCTL_SET_EXPORT: 335 error = vfs_export(mp, &xmp->export, export); 336 break; 337 default: 338 error = EOPNOTSUPP; 339 break; 340 } 341 return(error); 342 } 343 344 /* 345 * Pass through file handle conversion functions. 346 */ 347 static int 348 nullfs_vptofh(struct vnode *vp, struct fid *fhp) 349 { 350 return VFS_VPTOFH(vp, fhp); 351 } 352 353 /* 354 * Pass through file handle conversion functions. 355 * 356 * NOTE: currently only HAMMER uses rootvp. HAMMER uses rootvp only 357 * to enforce PFS isolation. 358 */ 359 static int 360 nullfs_fhtovp(struct mount *mp, struct vnode *rootvp, 361 struct fid *fhp, struct vnode **vpp) 362 { 363 struct null_mount *xmp = MOUNTTONULLMOUNT(mp); 364 365 return VFS_FHTOVP(xmp->nullm_vfs, xmp->nullm_rootvp, fhp, vpp); 366 } 367 368 static int 369 nullfs_extattrctl(struct mount *mp, int cmd, struct vnode *vp, 370 int attrnamespace, const char *attrname, struct ucred *cred) 371 { 372 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, 373 vp, attrnamespace, attrname, cred); 374 } 375 376 static void 377 nullfs_ncpgen_set(struct mount *mp, struct namecache *ncp) 378 { 379 struct null_mount *xmp = MOUNTTONULLMOUNT(mp); 380 381 VFS_NCPGEN_SET(xmp->nullm_vfs, ncp); 382 } 383 384 385 static int 386 nullfs_ncpgen_test(struct mount *mp, struct namecache *ncp) 387 { 388 struct null_mount *xmp = MOUNTTONULLMOUNT(mp); 389 390 return VFS_NCPGEN_TEST(xmp->nullm_vfs, ncp); 391 } 392 393 394 static struct vfsops null_vfsops = { 395 .vfs_mount = nullfs_mount, 396 .vfs_unmount = nullfs_unmount, 397 .vfs_root = nullfs_root, 398 .vfs_quotactl = nullfs_quotactl, 399 .vfs_statfs = nullfs_statfs, 400 .vfs_sync = vfs_stdsync, 401 .vfs_extattrctl = nullfs_extattrctl, 402 .vfs_fhtovp = nullfs_fhtovp, 403 .vfs_vptofh = nullfs_vptofh, 404 .vfs_ncpgen_set = nullfs_ncpgen_set, 405 .vfs_ncpgen_test = nullfs_ncpgen_test, 406 .vfs_checkexp = nullfs_checkexp 407 }; 408 409 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 410 MODULE_VERSION(null, 1); 411