null_vfsops.c revision 229431
117680Spst/*- 217680Spst * Copyright (c) 1992, 1993, 1995 317680Spst * The Regents of the University of California. All rights reserved. 417680Spst * 517680Spst * This code is derived from software donated to Berkeley by 617680Spst * Jan-Simon Pendry. 717680Spst * 817680Spst * Redistribution and use in source and binary forms, with or without 917680Spst * modification, are permitted provided that the following conditions 1017680Spst * are met: 1117680Spst * 1. Redistributions of source code must retain the above copyright 1217680Spst * notice, this list of conditions and the following disclaimer. 1317680Spst * 2. Redistributions in binary form must reproduce the above copyright 1417680Spst * notice, this list of conditions and the following disclaimer in the 1517680Spst * documentation and/or other materials provided with the distribution. 1617680Spst * 4. Neither the name of the University nor the names of its contributors 1717680Spst * may be used to endorse or promote products derived from this software 1817680Spst * without specific prior written permission. 1917680Spst * 2017680Spst * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2117680Spst * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2217680Spst * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2317680Spst * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2417680Spst * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2517680Spst * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2617680Spst * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2717680Spst * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2817680Spst * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2917680Spst * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3017680Spst * SUCH DAMAGE. 3117680Spst * 3217680Spst * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 3317680Spst * 3417680Spst * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 3517680Spst * $FreeBSD: head/sys/fs/nullfs/null_vfsops.c 229431 2012-01-03 21:09:07Z kib $ 3621262Swollman */ 3717680Spst 3817680Spst/* 3917680Spst * Null Layer 4017680Spst * (See null_vnops.c for a description of what this does.) 4117680Spst */ 4217680Spst 4317680Spst#include <sys/param.h> 4417680Spst#include <sys/systm.h> 4517680Spst#include <sys/fcntl.h> 4617680Spst#include <sys/kernel.h> 4717680Spst#include <sys/lock.h> 4817680Spst#include <sys/malloc.h> 4917680Spst#include <sys/mount.h> 5017680Spst#include <sys/namei.h> 5117680Spst#include <sys/proc.h> 5217680Spst#include <sys/vnode.h> 5317680Spst 5417680Spst#include <fs/nullfs/null.h> 5517680Spst 5617680Spststatic MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure"); 5717680Spst 5817680Spststatic vfs_fhtovp_t nullfs_fhtovp; 5917680Spststatic vfs_mount_t nullfs_mount; 6017680Spststatic vfs_quotactl_t nullfs_quotactl; 6117680Spststatic vfs_root_t nullfs_root; 6217680Spststatic vfs_sync_t nullfs_sync; 6317680Spststatic vfs_statfs_t nullfs_statfs; 6417680Spststatic vfs_unmount_t nullfs_unmount; 6517680Spststatic vfs_vget_t nullfs_vget; 6617680Spststatic vfs_extattrctl_t nullfs_extattrctl; 6717680Spst 6817680Spst/* 6917680Spst * Mount null layer 7017680Spst */ 7117680Spststatic int 7217680Spstnullfs_mount(struct mount *mp) 7317680Spst{ 7417680Spst int error = 0; 7517680Spst struct vnode *lowerrootvp, *vp; 7617680Spst struct vnode *nullm_rootvp; 7717680Spst struct null_mount *xmp; 7817680Spst char *target; 7917680Spst int isvnunlocked = 0, len; 8017680Spst struct nameidata nd, *ndp = &nd; 8117680Spst 8217680Spst NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 8317680Spst 8417680Spst if (mp->mnt_flag & MNT_ROOTFS) 8517680Spst return (EOPNOTSUPP); 8617680Spst /* 8717680Spst * Update is a no-op 8817680Spst */ 8917680Spst if (mp->mnt_flag & MNT_UPDATE) { 9017680Spst /* 9117680Spst * Only support update mounts for NFS export. 9217680Spst */ 9317680Spst if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) 9417680Spst return (0); 9517680Spst else 9617680Spst return (EOPNOTSUPP); 9717680Spst } 9817680Spst 9917680Spst /* 10017680Spst * Get argument 10117680Spst */ 10217680Spst error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 10317680Spst if (error || target[len - 1] != '\0') 10417680Spst return (EINVAL); 10517680Spst 10617680Spst /* 10717680Spst * Unlock lower node to avoid possible deadlock. 10817680Spst */ 10917680Spst if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) && 11017680Spst VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) { 11117680Spst VOP_UNLOCK(mp->mnt_vnodecovered, 0); 11217680Spst isvnunlocked = 1; 11317680Spst } 11417680Spst /* 11517680Spst * Find lower node 11617680Spst */ 11717680Spst NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread); 11817680Spst error = namei(ndp); 11917680Spst /* 12017680Spst * Re-lock vnode. 12117680Spst */ 12217680Spst if (isvnunlocked) 12317680Spst vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY); 12417680Spst 12517680Spst if (error) 12617680Spst return (error); 12717680Spst NDFREE(ndp, NDF_ONLY_PNBUF); 12817680Spst 12917680Spst /* 13017680Spst * Sanity check on lower vnode 13117680Spst */ 132 lowerrootvp = ndp->ni_vp; 133 134 /* 135 * Check multi null mount to avoid `lock against myself' panic. 136 */ 137 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 138 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 139 vput(lowerrootvp); 140 return (EDEADLK); 141 } 142 143 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 144 M_NULLFSMNT, M_WAITOK); /* XXX */ 145 146 /* 147 * Save reference to underlying FS 148 */ 149 xmp->nullm_vfs = lowerrootvp->v_mount; 150 151 /* 152 * Save reference. Each mount also holds 153 * a reference on the root vnode. 154 */ 155 error = null_nodeget(mp, lowerrootvp, &vp); 156 /* 157 * Make sure the node alias worked 158 */ 159 if (error) { 160 free(xmp, M_NULLFSMNT); 161 return (error); 162 } 163 164 /* 165 * Keep a held reference to the root vnode. 166 * It is vrele'd in nullfs_unmount. 167 */ 168 nullm_rootvp = vp; 169 nullm_rootvp->v_vflag |= VV_ROOT; 170 xmp->nullm_rootvp = nullm_rootvp; 171 172 /* 173 * Unlock the node (either the lower or the alias) 174 */ 175 VOP_UNLOCK(vp, 0); 176 177 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) { 178 MNT_ILOCK(mp); 179 mp->mnt_flag |= MNT_LOCAL; 180 MNT_IUNLOCK(mp); 181 } 182 MNT_ILOCK(mp); 183 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE; 184 MNT_IUNLOCK(mp); 185 mp->mnt_data = xmp; 186 vfs_getnewfsid(mp); 187 188 vfs_mountedfrom(mp, target); 189 190 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 * Free reference to null layer 197 */ 198static int 199nullfs_unmount(mp, mntflags) 200 struct mount *mp; 201 int mntflags; 202{ 203 void *mntdata; 204 int error; 205 int flags = 0; 206 207 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 208 209 if (mntflags & MNT_FORCE) 210 flags |= FORCECLOSE; 211 212 /* There is 1 extra root vnode reference (nullm_rootvp). */ 213 error = vflush(mp, 1, flags, curthread); 214 if (error) 215 return (error); 216 217 /* 218 * Finally, throw away the null_mount structure 219 */ 220 mntdata = mp->mnt_data; 221 mp->mnt_data = 0; 222 free(mntdata, M_NULLFSMNT); 223 return 0; 224} 225 226static int 227nullfs_root(mp, flags, vpp) 228 struct mount *mp; 229 int flags; 230 struct vnode **vpp; 231{ 232 struct vnode *vp; 233 234 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 235 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 236 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 237 238 /* 239 * Return locked reference to root. 240 */ 241 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 242 VREF(vp); 243 244 ASSERT_VOP_UNLOCKED(vp, "root vnode is locked"); 245 vn_lock(vp, flags | LK_RETRY); 246 *vpp = vp; 247 return 0; 248} 249 250static int 251nullfs_quotactl(mp, cmd, uid, arg) 252 struct mount *mp; 253 int cmd; 254 uid_t uid; 255 void *arg; 256{ 257 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg); 258} 259 260static int 261nullfs_statfs(mp, sbp) 262 struct mount *mp; 263 struct statfs *sbp; 264{ 265 int error; 266 struct statfs mstat; 267 268 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 269 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 270 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 271 272 bzero(&mstat, sizeof(mstat)); 273 274 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat); 275 if (error) 276 return (error); 277 278 /* now copy across the "interesting" information and fake the rest */ 279 sbp->f_type = mstat.f_type; 280 sbp->f_flags = mstat.f_flags; 281 sbp->f_bsize = mstat.f_bsize; 282 sbp->f_iosize = mstat.f_iosize; 283 sbp->f_blocks = mstat.f_blocks; 284 sbp->f_bfree = mstat.f_bfree; 285 sbp->f_bavail = mstat.f_bavail; 286 sbp->f_files = mstat.f_files; 287 sbp->f_ffree = mstat.f_ffree; 288 return (0); 289} 290 291static int 292nullfs_sync(mp, waitfor) 293 struct mount *mp; 294 int waitfor; 295{ 296 /* 297 * XXX - Assumes no data cached at null layer. 298 */ 299 return (0); 300} 301 302static int 303nullfs_vget(mp, ino, flags, vpp) 304 struct mount *mp; 305 ino_t ino; 306 int flags; 307 struct vnode **vpp; 308{ 309 int error; 310 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 311 if (error) 312 return (error); 313 314 return (null_nodeget(mp, *vpp, vpp)); 315} 316 317static int 318nullfs_fhtovp(mp, fidp, flags, vpp) 319 struct mount *mp; 320 struct fid *fidp; 321 int flags; 322 struct vnode **vpp; 323{ 324 int error; 325 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, LK_EXCLUSIVE, 326 vpp); 327 if (error) 328 return (error); 329 330 return (null_nodeget(mp, *vpp, vpp)); 331} 332 333static int 334nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname) 335 struct mount *mp; 336 int cmd; 337 struct vnode *filename_vp; 338 int namespace; 339 const char *attrname; 340{ 341 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 342 namespace, attrname); 343} 344 345 346static struct vfsops null_vfsops = { 347 .vfs_extattrctl = nullfs_extattrctl, 348 .vfs_fhtovp = nullfs_fhtovp, 349 .vfs_init = nullfs_init, 350 .vfs_mount = nullfs_mount, 351 .vfs_quotactl = nullfs_quotactl, 352 .vfs_root = nullfs_root, 353 .vfs_statfs = nullfs_statfs, 354 .vfs_sync = nullfs_sync, 355 .vfs_uninit = nullfs_uninit, 356 .vfs_unmount = nullfs_unmount, 357 .vfs_vget = nullfs_vget, 358}; 359 360VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 361