Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/nullfs/null_vfsops.c
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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: releng/5.3/sys/fs/nullfs/null_vfsops.c 132902 2004-07-30 22:08:52Z phk $ 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/kdb.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_checkexp_t nullfs_checkexp; 60 static vfs_mount_t nullfs_mount; 61 static vfs_quotactl_t nullfs_quotactl; 62 static vfs_root_t nullfs_root; 63 static vfs_start_t nullfs_start; 64 static vfs_sync_t nullfs_sync; 65 static vfs_statfs_t nullfs_statfs; 66 static vfs_unmount_t nullfs_unmount; 67 static vfs_vget_t nullfs_vget; 68 static vfs_vptofh_t nullfs_vptofh; 69 static vfs_extattrctl_t nullfs_extattrctl; 70 71 /* 72 * Mount null layer 73 */ 74 static int 75 nullfs_mount(struct mount *mp, struct thread *td) 76 { 77 int error = 0; 78 struct vnode *lowerrootvp, *vp; 79 struct vnode *nullm_rootvp; 80 struct null_mount *xmp; 81 char *target; 82 size_t size; 83 int isvnunlocked = 0, len; 84 struct nameidata nd, *ndp = &nd; 85 86 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 87 88 /* 89 * Update is a no-op 90 */ 91 if (mp->mnt_flag & MNT_UPDATE) { 92 return (EOPNOTSUPP); 93 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/ 94 } 95 96 /* 97 * Get argument 98 */ 99 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 100 if (error || target[len - 1] != '\0') 101 return (EINVAL); 102 103 /* 104 * Unlock lower node to avoid deadlock. 105 * (XXX) VOP_ISLOCKED is needed? 106 */ 107 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 108 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 109 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 110 isvnunlocked = 1; 111 } 112 /* 113 * Find lower node 114 */ 115 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 116 UIO_SYSSPACE, target, td); 117 error = namei(ndp); 118 /* 119 * Re-lock vnode. 120 */ 121 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 122 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 123 124 if (error) 125 return (error); 126 NDFREE(ndp, NDF_ONLY_PNBUF); 127 128 /* 129 * Sanity check on lower vnode 130 */ 131 lowerrootvp = ndp->ni_vp; 132 133 vrele(ndp->ni_dvp); 134 ndp->ni_dvp = NULLVP; 135 136 /* 137 * Check multi null mount to avoid `lock against myself' panic. 138 */ 139 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 140 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 141 vput(lowerrootvp); 142 return (EDEADLK); 143 } 144 145 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 146 M_NULLFSMNT, M_WAITOK); /* XXX */ 147 148 /* 149 * Save reference to underlying FS 150 */ 151 xmp->nullm_vfs = lowerrootvp->v_mount; 152 153 /* 154 * Save reference. Each mount also holds 155 * a reference on the root vnode. 156 */ 157 error = null_nodeget(mp, lowerrootvp, &vp); 158 /* 159 * Make sure the node alias worked 160 */ 161 if (error) { 162 VOP_UNLOCK(vp, 0, td); 163 vrele(lowerrootvp); 164 free(xmp, M_NULLFSMNT); /* XXX */ 165 return (error); 166 } 167 168 /* 169 * Keep a held reference to the root vnode. 170 * It is vrele'd in nullfs_unmount. 171 */ 172 nullm_rootvp = vp; 173 nullm_rootvp->v_vflag |= VV_ROOT; 174 xmp->nullm_rootvp = nullm_rootvp; 175 176 /* 177 * Unlock the node (either the lower or the alias) 178 */ 179 VOP_UNLOCK(vp, 0, td); 180 181 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 182 mp->mnt_flag |= MNT_LOCAL; 183 mp->mnt_data = (qaddr_t) xmp; 184 vfs_getnewfsid(mp); 185 186 (void) copystr(target, mp->mnt_stat.f_mntfromname, 187 MNAMELEN - 1, &size); 188 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 189 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 190 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 191 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 192 return (0); 193 } 194 195 /* 196 * VFS start. Nothing needed here - the start routine 197 * on the underlying filesystem will have been called 198 * when that filesystem was mounted. 199 */ 200 static int 201 nullfs_start(mp, flags, td) 202 struct mount *mp; 203 int flags; 204 struct thread *td; 205 { 206 return (0); 207 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 208 } 209 210 /* 211 * Free reference to null layer 212 */ 213 static int 214 nullfs_unmount(mp, mntflags, td) 215 struct mount *mp; 216 int mntflags; 217 struct thread *td; 218 { 219 void *mntdata; 220 int error; 221 int flags = 0; 222 223 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 224 225 if (mntflags & MNT_FORCE) 226 flags |= FORCECLOSE; 227 228 /* There is 1 extra root vnode reference (nullm_rootvp). */ 229 error = vflush(mp, 1, flags, td); 230 if (error) 231 return (error); 232 233 /* 234 * Finally, throw away the null_mount structure 235 */ 236 mntdata = mp->mnt_data; 237 mp->mnt_data = 0; 238 free(mntdata, M_NULLFSMNT); 239 return 0; 240 } 241 242 static int 243 nullfs_root(mp, vpp, td) 244 struct mount *mp; 245 struct vnode **vpp; 246 struct thread *td; 247 { 248 struct vnode *vp; 249 250 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 251 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 252 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 253 254 /* 255 * Return locked reference to root. 256 */ 257 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 258 VREF(vp); 259 260 #ifdef NULLFS_DEBUG 261 if (VOP_ISLOCKED(vp, NULL)) { 262 kdb_enter("root vnode is locked.\n"); 263 vrele(vp); 264 return (EDEADLK); 265 } 266 #endif 267 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 268 *vpp = vp; 269 return 0; 270 } 271 272 static int 273 nullfs_quotactl(mp, cmd, uid, arg, td) 274 struct mount *mp; 275 int cmd; 276 uid_t uid; 277 caddr_t arg; 278 struct thread *td; 279 { 280 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 281 } 282 283 static int 284 nullfs_statfs(mp, sbp, td) 285 struct mount *mp; 286 struct statfs *sbp; 287 struct thread *td; 288 { 289 int error; 290 struct statfs mstat; 291 292 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 293 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 294 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 295 296 bzero(&mstat, sizeof(mstat)); 297 298 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 299 if (error) 300 return (error); 301 302 /* now copy across the "interesting" information and fake the rest */ 303 sbp->f_type = mstat.f_type; 304 sbp->f_flags = mstat.f_flags; 305 sbp->f_bsize = mstat.f_bsize; 306 sbp->f_iosize = mstat.f_iosize; 307 sbp->f_blocks = mstat.f_blocks; 308 sbp->f_bfree = mstat.f_bfree; 309 sbp->f_bavail = mstat.f_bavail; 310 sbp->f_files = mstat.f_files; 311 sbp->f_ffree = mstat.f_ffree; 312 if (sbp != &mp->mnt_stat) { 313 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 314 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 315 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 316 } 317 return (0); 318 } 319 320 static int 321 nullfs_sync(mp, waitfor, cred, td) 322 struct mount *mp; 323 int waitfor; 324 struct ucred *cred; 325 struct thread *td; 326 { 327 /* 328 * XXX - Assumes no data cached at null layer. 329 */ 330 return (0); 331 } 332 333 static int 334 nullfs_vget(mp, ino, flags, vpp) 335 struct mount *mp; 336 ino_t ino; 337 int flags; 338 struct vnode **vpp; 339 { 340 int error; 341 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 342 if (error) 343 return (error); 344 345 return (null_nodeget(mp, *vpp, vpp)); 346 } 347 348 static int 349 nullfs_fhtovp(mp, fidp, vpp) 350 struct mount *mp; 351 struct fid *fidp; 352 struct vnode **vpp; 353 { 354 int error; 355 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 356 if (error) 357 return (error); 358 359 return (null_nodeget(mp, *vpp, vpp)); 360 } 361 362 static int 363 nullfs_checkexp(mp, nam, extflagsp, credanonp) 364 struct mount *mp; 365 struct sockaddr *nam; 366 int *extflagsp; 367 struct ucred **credanonp; 368 { 369 370 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 371 extflagsp, credanonp); 372 } 373 374 static int 375 nullfs_vptofh(vp, fhp) 376 struct vnode *vp; 377 struct fid *fhp; 378 { 379 struct vnode *lvp; 380 381 lvp = NULLVPTOLOWERVP(vp); 382 return VFS_VPTOFH(lvp, fhp); 383 } 384 385 static int 386 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td) 387 struct mount *mp; 388 int cmd; 389 struct vnode *filename_vp; 390 int namespace; 391 const char *attrname; 392 struct thread *td; 393 { 394 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 395 namespace, attrname, td); 396 } 397 398 399 static struct vfsops null_vfsops = { 400 .vfs_checkexp = nullfs_checkexp, 401 .vfs_extattrctl = nullfs_extattrctl, 402 .vfs_fhtovp = nullfs_fhtovp, 403 .vfs_init = nullfs_init, 404 .vfs_mount = nullfs_mount, 405 .vfs_quotactl = nullfs_quotactl, 406 .vfs_root = nullfs_root, 407 .vfs_start = nullfs_start, 408 .vfs_statfs = nullfs_statfs, 409 .vfs_sync = nullfs_sync, 410 .vfs_uninit = nullfs_uninit, 411 .vfs_unmount = nullfs_unmount, 412 .vfs_vget = nullfs_vget, 413 .vfs_vptofh = nullfs_vptofh, 414 }; 415 416 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);
Cache object: b4e940dfcf6947fad96c7c2d927701fd
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