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 1.17 2005/07/26 15:43:36 hmp 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_statfs(struct mount *mp, struct statfs *sbp, 72 struct thread *td); 73 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 74 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 75 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 76 static int nullfs_extattrctl(struct mount *mp, int cmd, 77 const char *attrname, caddr_t arg, struct thread *td); 78 79 /* 80 * Mount null layer 81 */ 82 static int 83 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td) 84 { 85 int error = 0; 86 struct null_args args; 87 struct vnode *lowerrootvp, *vp; 88 struct vnode *nullm_rootvp; 89 struct null_mount *xmp; 90 u_int size; 91 int isvnunlocked = 0; 92 struct nlookupdata nd; 93 94 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 95 96 /* 97 * Update is a no-op 98 */ 99 if (mp->mnt_flag & MNT_UPDATE) { 100 return (EOPNOTSUPP); 101 } 102 103 /* 104 * Get argument 105 */ 106 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 107 if (error) 108 return (error); 109 110 /* 111 * Unlock lower node to avoid deadlock. 112 * (XXX) VOP_ISLOCKED is needed? 113 */ 114 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) && 115 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 116 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 117 isvnunlocked = 1; 118 } 119 /* 120 * Find lower node 121 */ 122 lowerrootvp = NULL; 123 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW); 124 if (error == 0) 125 error = nlookup(&nd); 126 if (error == 0) { 127 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE, 128 &lowerrootvp); 129 } 130 nlookup_done(&nd); 131 132 /* 133 * Re-lock vnode. 134 */ 135 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 136 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 137 if (error) 138 return (error); 139 140 /* 141 * Sanity check on lower vnode 142 * 143 * Check multi null mount to avoid `lock against myself' panic. 144 */ 145 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 146 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 147 vput(lowerrootvp); 148 return (EDEADLK); 149 } 150 151 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 152 M_NULLFSMNT, M_WAITOK); /* XXX */ 153 154 /* 155 * Save reference to underlying FS 156 */ 157 xmp->nullm_vfs = lowerrootvp->v_mount; 158 159 vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops, null_vnodeop_entries); 160 161 /* 162 * Save reference. Each mount also holds 163 * a reference on the root vnode. 164 */ 165 error = null_node_create(mp, lowerrootvp, &vp); 166 /* 167 * Unlock the node (either the lower or the alias) 168 */ 169 VOP_UNLOCK(vp, 0, td); 170 /* 171 * Make sure the node alias worked 172 */ 173 if (error) { 174 vrele(lowerrootvp); 175 free(xmp, M_NULLFSMNT); /* XXX */ 176 return (error); 177 } 178 179 /* 180 * Keep a held reference to the root vnode. 181 * It is vrele'd in nullfs_unmount. 182 */ 183 nullm_rootvp = vp; 184 nullm_rootvp->v_flag |= VROOT; 185 xmp->nullm_rootvp = nullm_rootvp; 186 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 187 mp->mnt_flag |= MNT_LOCAL; 188 mp->mnt_data = (qaddr_t) xmp; 189 vfs_getnewfsid(mp); 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, td); 195 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 196 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname); 197 return (0); 198 } 199 200 /* 201 * Free reference to null layer 202 */ 203 static int 204 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 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); 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(struct mount *mp, struct vnode **vpp) 231 { 232 struct thread *td = curthread; /* XXX */ 233 struct vnode *vp; 234 235 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 236 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 237 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 238 239 /* 240 * Return locked reference to root. 241 */ 242 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 243 vref(vp); 244 245 #ifdef NULLFS_DEBUG 246 if (VOP_ISLOCKED(vp, NULL)) { 247 Debugger("root vnode is locked.\n"); 248 vrele(vp); 249 return (EDEADLK); 250 } 251 #endif 252 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 253 *vpp = vp; 254 return 0; 255 } 256 257 static int 258 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 259 struct thread *td) 260 { 261 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 262 } 263 264 static int 265 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 266 { 267 int error; 268 struct statfs mstat; 269 270 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 271 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 272 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 273 274 bzero(&mstat, sizeof(mstat)); 275 276 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 277 if (error) 278 return (error); 279 280 /* now copy across the "interesting" information and fake the rest */ 281 sbp->f_type = mstat.f_type; 282 sbp->f_flags = mstat.f_flags; 283 sbp->f_bsize = mstat.f_bsize; 284 sbp->f_iosize = mstat.f_iosize; 285 sbp->f_blocks = mstat.f_blocks; 286 sbp->f_bfree = mstat.f_bfree; 287 sbp->f_bavail = mstat.f_bavail; 288 sbp->f_files = mstat.f_files; 289 sbp->f_ffree = mstat.f_ffree; 290 if (sbp != &mp->mnt_stat) { 291 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 292 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 293 } 294 return (0); 295 } 296 297 static int 298 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 299 { 300 301 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 302 } 303 304 static int 305 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 306 { 307 308 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 309 } 310 311 static int 312 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 313 struct ucred **credanonp) 314 { 315 316 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 317 extflagsp, credanonp); 318 } 319 320 static int 321 nullfs_vptofh(struct vnode *vp, struct fid *fhp) 322 { 323 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 324 } 325 326 static int 327 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 328 struct thread *td) 329 { 330 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 331 arg, td); 332 } 333 334 335 static struct vfsops null_vfsops = { 336 .vfs_mount = nullfs_mount, 337 .vfs_unmount = nullfs_unmount, 338 .vfs_root = nullfs_root, 339 .vfs_quotactl = nullfs_quotactl, 340 .vfs_statfs = nullfs_statfs, 341 .vfs_sync = vfs_stdsync, 342 .vfs_vget = nullfs_vget, 343 .vfs_fhtovp = nullfs_fhtovp, 344 .vfs_checkexp = nullfs_checkexp, 345 .vfs_vptofh = nullfs_vptofh, 346 .vfs_init = nullfs_init, 347 .vfs_uninit = nullfs_uninit, 348 .vfs_extattrctl = nullfs_extattrctl 349 }; 350 351 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 352