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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 33 * 34 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 35 * $FreeBSD$ 36 */ 37 38 /* 39 * Null Layer 40 * (See null_vnops.c for a description of what this does.) 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/fcntl.h> 46 #include <sys/kernel.h> 47 #include <sys/lock.h> 48 #include <sys/malloc.h> 49 #include <sys/mount.h> 50 #include <sys/namei.h> 51 #include <sys/proc.h> 52 #include <sys/vnode.h> 53 54 #include <fs/nullfs/null.h> 55 56 static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure"); 57 58 static vfs_fhtovp_t nullfs_fhtovp; 59 static vfs_mount_t nullfs_mount; 60 static vfs_quotactl_t nullfs_quotactl; 61 static vfs_root_t nullfs_root; 62 static vfs_sync_t nullfs_sync; 63 static vfs_statfs_t nullfs_statfs; 64 static vfs_unmount_t nullfs_unmount; 65 static vfs_vget_t nullfs_vget; 66 static vfs_extattrctl_t nullfs_extattrctl; 67 68 /* 69 * Mount null layer 70 */ 71 static int 72 nullfs_mount(struct mount *mp) 73 { 74 int error = 0; 75 struct vnode *lowerrootvp, *vp; 76 struct vnode *nullm_rootvp; 77 struct null_mount *xmp; 78 char *target; 79 int isvnunlocked = 0, len; 80 struct nameidata nd, *ndp = &nd; 81 82 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 83 84 if (mp->mnt_flag & MNT_ROOTFS) 85 return (EOPNOTSUPP); 86 /* 87 * Update is a no-op 88 */ 89 if (mp->mnt_flag & MNT_UPDATE) { 90 /* 91 * Only support update mounts for NFS export. 92 */ 93 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) 94 return (0); 95 else 96 return (EOPNOTSUPP); 97 } 98 99 /* 100 * Get argument 101 */ 102 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 103 if (error || target[len - 1] != '\0') 104 return (EINVAL); 105 106 /* 107 * Unlock lower node to avoid deadlock. 108 * (XXX) VOP_ISLOCKED is needed? 109 */ 110 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) && 111 VOP_ISLOCKED(mp->mnt_vnodecovered)) { 112 VOP_UNLOCK(mp->mnt_vnodecovered, 0); 113 isvnunlocked = 1; 114 } 115 /* 116 * Find lower node 117 */ 118 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread); 119 error = namei(ndp); 120 /* 121 * Re-lock vnode. 122 */ 123 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered)) 124 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY); 125 126 if (error) 127 return (error); 128 NDFREE(ndp, NDF_ONLY_PNBUF); 129 130 /* 131 * Sanity check on lower vnode 132 */ 133 lowerrootvp = ndp->ni_vp; 134 135 /* 136 * Check multi null mount to avoid `lock against myself' panic. 137 */ 138 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 139 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 140 vput(lowerrootvp); 141 return (EDEADLK); 142 } 143 144 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 145 M_NULLFSMNT, M_WAITOK); /* XXX */ 146 147 /* 148 * Save reference to underlying FS 149 */ 150 xmp->nullm_vfs = lowerrootvp->v_mount; 151 152 /* 153 * Save reference. Each mount also holds 154 * a reference on the root vnode. 155 */ 156 error = null_nodeget(mp, lowerrootvp, &vp); 157 /* 158 * Make sure the node alias worked 159 */ 160 if (error) { 161 VOP_UNLOCK(vp, 0); 162 vrele(lowerrootvp); 163 free(xmp, M_NULLFSMNT); /* XXX */ 164 return (error); 165 } 166 167 /* 168 * Keep a held reference to the root vnode. 169 * It is vrele'd in nullfs_unmount. 170 */ 171 nullm_rootvp = vp; 172 nullm_rootvp->v_vflag |= VV_ROOT; 173 xmp->nullm_rootvp = nullm_rootvp; 174 175 /* 176 * Unlock the node (either the lower or the alias) 177 */ 178 VOP_UNLOCK(vp, 0); 179 180 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) { 181 MNT_ILOCK(mp); 182 mp->mnt_flag |= MNT_LOCAL; 183 MNT_IUNLOCK(mp); 184 } 185 MNT_ILOCK(mp); 186 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE; 187 MNT_IUNLOCK(mp); 188 mp->mnt_data = xmp; 189 vfs_getnewfsid(mp); 190 191 vfs_mountedfrom(mp, target); 192 193 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 194 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 195 return (0); 196 } 197 198 /* 199 * Free reference to null layer 200 */ 201 static int 202 nullfs_unmount(mp, mntflags) 203 struct mount *mp; 204 int mntflags; 205 { 206 void *mntdata; 207 int error; 208 int flags = 0; 209 210 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 211 212 if (mntflags & MNT_FORCE) 213 flags |= FORCECLOSE; 214 215 /* There is 1 extra root vnode reference (nullm_rootvp). */ 216 error = vflush(mp, 1, flags, curthread); 217 if (error) 218 return (error); 219 220 /* 221 * Finally, throw away the null_mount structure 222 */ 223 mntdata = mp->mnt_data; 224 mp->mnt_data = 0; 225 free(mntdata, M_NULLFSMNT); 226 return 0; 227 } 228 229 static int 230 nullfs_root(mp, flags, vpp) 231 struct mount *mp; 232 int flags; 233 struct vnode **vpp; 234 { 235 struct vnode *vp; 236 237 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 238 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 239 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 240 241 /* 242 * Return locked reference to root. 243 */ 244 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 245 VREF(vp); 246 247 #ifdef NULLFS_DEBUG 248 if (VOP_ISLOCKED(vp)) 249 panic("root vnode is locked.\n"); 250 #endif 251 vn_lock(vp, flags | LK_RETRY); 252 *vpp = vp; 253 return 0; 254 } 255 256 static int 257 nullfs_quotactl(mp, cmd, uid, arg) 258 struct mount *mp; 259 int cmd; 260 uid_t uid; 261 void *arg; 262 { 263 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg); 264 } 265 266 static int 267 nullfs_statfs(mp, sbp) 268 struct mount *mp; 269 struct statfs *sbp; 270 { 271 int error; 272 struct statfs mstat; 273 274 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 275 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 276 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 277 278 bzero(&mstat, sizeof(mstat)); 279 280 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat); 281 if (error) 282 return (error); 283 284 /* now copy across the "interesting" information and fake the rest */ 285 sbp->f_type = mstat.f_type; 286 sbp->f_flags = mstat.f_flags; 287 sbp->f_bsize = mstat.f_bsize; 288 sbp->f_iosize = mstat.f_iosize; 289 sbp->f_blocks = mstat.f_blocks; 290 sbp->f_bfree = mstat.f_bfree; 291 sbp->f_bavail = mstat.f_bavail; 292 sbp->f_files = mstat.f_files; 293 sbp->f_ffree = mstat.f_ffree; 294 return (0); 295 } 296 297 static int 298 nullfs_sync(mp, waitfor) 299 struct mount *mp; 300 int waitfor; 301 { 302 /* 303 * XXX - Assumes no data cached at null layer. 304 */ 305 return (0); 306 } 307 308 static int 309 nullfs_vget(mp, ino, flags, vpp) 310 struct mount *mp; 311 ino_t ino; 312 int flags; 313 struct vnode **vpp; 314 { 315 int error; 316 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 317 if (error) 318 return (error); 319 320 return (null_nodeget(mp, *vpp, vpp)); 321 } 322 323 static int 324 nullfs_fhtovp(mp, fidp, vpp) 325 struct mount *mp; 326 struct fid *fidp; 327 struct vnode **vpp; 328 { 329 int error; 330 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 331 if (error) 332 return (error); 333 334 return (null_nodeget(mp, *vpp, vpp)); 335 } 336 337 static int 338 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname) 339 struct mount *mp; 340 int cmd; 341 struct vnode *filename_vp; 342 int namespace; 343 const char *attrname; 344 { 345 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 346 namespace, attrname); 347 } 348 349 350 static struct vfsops null_vfsops = { 351 .vfs_extattrctl = nullfs_extattrctl, 352 .vfs_fhtovp = nullfs_fhtovp, 353 .vfs_init = nullfs_init, 354 .vfs_mount = nullfs_mount, 355 .vfs_quotactl = nullfs_quotactl, 356 .vfs_root = nullfs_root, 357 .vfs_statfs = nullfs_statfs, 358 .vfs_sync = nullfs_sync, 359 .vfs_uninit = nullfs_uninit, 360 .vfs_unmount = nullfs_unmount, 361 .vfs_vget = nullfs_vget, 362 }; 363 364 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 365