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 1.16 2005/02/02 21:34:18 joerg 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/nlookup.h> 56 #include "null.h" 57 58 extern struct vnodeopv_entry_desc null_vnodeop_entries[]; 59 60 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 61 62 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 63 struct vnode **vpp); 64 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 65 int *extflagsp, struct ucred **credanonp); 66 static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 67 struct thread *td); 68 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 69 caddr_t arg, struct thread *td); 70 static int nullfs_root(struct mount *mp, struct vnode **vpp); 71 static int nullfs_start(struct mount *mp, int flags, struct thread *td); 72 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 73 struct thread *td); 74 static int nullfs_sync(struct mount *mp, int waitfor, struct thread *td); 75 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 76 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 77 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 78 static int nullfs_extattrctl(struct mount *mp, int cmd, 79 const char *attrname, caddr_t arg, struct thread *td); 80 81 /* 82 * Mount null layer 83 */ 84 static int 85 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td) 86 { 87 int error = 0; 88 struct null_args args; 89 struct vnode *lowerrootvp, *vp; 90 struct vnode *nullm_rootvp; 91 struct null_mount *xmp; 92 u_int size; 93 int isvnunlocked = 0; 94 struct nlookupdata nd; 95 96 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 97 98 /* 99 * Update is a no-op 100 */ 101 if (mp->mnt_flag & MNT_UPDATE) { 102 return (EOPNOTSUPP); 103 } 104 105 /* 106 * Get argument 107 */ 108 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 109 if (error) 110 return (error); 111 112 /* 113 * Unlock lower node to avoid deadlock. 114 * (XXX) VOP_ISLOCKED is needed? 115 */ 116 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) && 117 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 118 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 119 isvnunlocked = 1; 120 } 121 /* 122 * Find lower node 123 */ 124 lowerrootvp = NULL; 125 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW); 126 if (error == 0) 127 error = nlookup(&nd); 128 if (error == 0) { 129 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE, 130 &lowerrootvp); 131 } 132 nlookup_done(&nd); 133 134 /* 135 * Re-lock vnode. 136 */ 137 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 138 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 139 if (error) 140 return (error); 141 142 /* 143 * Sanity check on lower vnode 144 * 145 * Check multi null mount to avoid `lock against myself' panic. 146 */ 147 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 148 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 149 vput(lowerrootvp); 150 return (EDEADLK); 151 } 152 153 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 154 M_NULLFSMNT, M_WAITOK); /* XXX */ 155 156 /* 157 * Save reference to underlying FS 158 */ 159 xmp->nullm_vfs = lowerrootvp->v_mount; 160 161 vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops, null_vnodeop_entries); 162 163 /* 164 * Save reference. Each mount also holds 165 * a reference on the root vnode. 166 */ 167 error = null_node_create(mp, lowerrootvp, &vp); 168 /* 169 * Unlock the node (either the lower or the alias) 170 */ 171 VOP_UNLOCK(vp, 0, td); 172 /* 173 * Make sure the node alias worked 174 */ 175 if (error) { 176 vrele(lowerrootvp); 177 free(xmp, M_NULLFSMNT); /* XXX */ 178 return (error); 179 } 180 181 /* 182 * Keep a held reference to the root vnode. 183 * It is vrele'd in nullfs_unmount. 184 */ 185 nullm_rootvp = vp; 186 nullm_rootvp->v_flag |= VROOT; 187 xmp->nullm_rootvp = nullm_rootvp; 188 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 189 mp->mnt_flag |= MNT_LOCAL; 190 mp->mnt_data = (qaddr_t) xmp; 191 vfs_getnewfsid(mp); 192 193 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 194 &size); 195 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 196 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 197 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 198 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname); 199 return (0); 200 } 201 202 /* 203 * VFS start. Nothing needed here - the start routine 204 * on the underlying filesystem will have been called 205 * when that filesystem was mounted. 206 */ 207 static int 208 nullfs_start(struct mount *mp, int flags, struct thread *td) 209 { 210 return (0); 211 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 212 } 213 214 /* 215 * Free reference to null layer 216 */ 217 static int 218 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 219 { 220 void *mntdata; 221 int error; 222 int flags = 0; 223 224 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 225 226 if (mntflags & MNT_FORCE) 227 flags |= FORCECLOSE; 228 229 /* There is 1 extra root vnode reference (nullm_rootvp). */ 230 error = vflush(mp, 1, flags); 231 if (error) 232 return (error); 233 234 /* 235 * Finally, throw away the null_mount structure 236 */ 237 mntdata = mp->mnt_data; 238 mp->mnt_data = 0; 239 free(mntdata, M_NULLFSMNT); 240 return 0; 241 } 242 243 static int 244 nullfs_root(struct mount *mp, struct vnode **vpp) 245 { 246 struct thread *td = curthread; /* XXX */ 247 struct vnode *vp; 248 249 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 250 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 251 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 252 253 /* 254 * Return locked reference to root. 255 */ 256 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 257 vref(vp); 258 259 #ifdef NULLFS_DEBUG 260 if (VOP_ISLOCKED(vp, NULL)) { 261 Debugger("root vnode is locked.\n"); 262 vrele(vp); 263 return (EDEADLK); 264 } 265 #endif 266 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 267 *vpp = vp; 268 return 0; 269 } 270 271 static int 272 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 273 struct thread *td) 274 { 275 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 276 } 277 278 static int 279 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 280 { 281 int error; 282 struct statfs mstat; 283 284 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 285 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 286 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 287 288 bzero(&mstat, sizeof(mstat)); 289 290 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 291 if (error) 292 return (error); 293 294 /* now copy across the "interesting" information and fake the rest */ 295 sbp->f_type = mstat.f_type; 296 sbp->f_flags = mstat.f_flags; 297 sbp->f_bsize = mstat.f_bsize; 298 sbp->f_iosize = mstat.f_iosize; 299 sbp->f_blocks = mstat.f_blocks; 300 sbp->f_bfree = mstat.f_bfree; 301 sbp->f_bavail = mstat.f_bavail; 302 sbp->f_files = mstat.f_files; 303 sbp->f_ffree = mstat.f_ffree; 304 if (sbp != &mp->mnt_stat) { 305 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 306 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 307 } 308 return (0); 309 } 310 311 static int 312 nullfs_sync(struct mount *mp, int waitfor, struct thread *td) 313 { 314 /* 315 * XXX - Assumes no data cached at null layer. 316 */ 317 return (0); 318 } 319 320 static int 321 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 322 { 323 324 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 325 } 326 327 static int 328 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 329 { 330 331 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 332 } 333 334 static int 335 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 336 struct ucred **credanonp) 337 { 338 339 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 340 extflagsp, credanonp); 341 } 342 343 static int 344 nullfs_vptofh(struct vnode *vp, struct fid *fhp) 345 { 346 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 347 } 348 349 static int 350 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 351 struct thread *td) 352 { 353 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 354 arg, td); 355 } 356 357 358 static struct vfsops null_vfsops = { 359 nullfs_mount, 360 nullfs_start, 361 nullfs_unmount, 362 nullfs_root, 363 nullfs_quotactl, 364 nullfs_statfs, 365 nullfs_sync, 366 nullfs_vget, 367 nullfs_fhtovp, 368 nullfs_checkexp, 369 nullfs_vptofh, 370 nullfs_init, 371 nullfs_uninit, 372 nullfs_extattrctl, 373 }; 374 375 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 376