| 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 1.18 2005/09/17 07:43:12 dillon 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, |
| 160 | null_vnodeop_entries, 0); |
| 161 | |
| 162 | /* |
| 163 | * Save reference. Each mount also holds |
| 164 | * a reference on the root vnode. |
| 165 | */ |
| 166 | error = null_node_create(mp, lowerrootvp, &vp); |
| 167 | /* |
| 168 | * Unlock the node (either the lower or the alias) |
| 169 | */ |
| 170 | VOP_UNLOCK(vp, 0, td); |
| 171 | /* |
| 172 | * Make sure the node alias worked |
| 173 | */ |
| 174 | if (error) { |
| 175 | vrele(lowerrootvp); |
| 176 | free(xmp, M_NULLFSMNT); /* XXX */ |
| 177 | return (error); |
| 178 | } |
| 179 | |
| 180 | /* |
| 181 | * Keep a held reference to the root vnode. |
| 182 | * It is vrele'd in nullfs_unmount. |
| 183 | */ |
| 184 | nullm_rootvp = vp; |
| 185 | nullm_rootvp->v_flag |= VROOT; |
| 186 | xmp->nullm_rootvp = nullm_rootvp; |
| 187 | if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) |
| 188 | mp->mnt_flag |= MNT_LOCAL; |
| 189 | mp->mnt_data = (qaddr_t) xmp; |
| 190 | vfs_getnewfsid(mp); |
| 191 | |
| 192 | (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, |
| 193 | &size); |
| 194 | bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); |
| 195 | (void)nullfs_statfs(mp, &mp->mnt_stat, td); |
| 196 | NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", |
| 197 | mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname); |
| 198 | return (0); |
| 199 | } |
| 200 | |
| 201 | /* |
| 202 | * Free reference to null layer |
| 203 | */ |
| 204 | static int |
| 205 | nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) |
| 206 | { |
| 207 | void *mntdata; |
| 208 | int error; |
| 209 | int flags = 0; |
| 210 | |
| 211 | NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); |
| 212 | |
| 213 | if (mntflags & MNT_FORCE) |
| 214 | flags |= FORCECLOSE; |
| 215 | |
| 216 | /* There is 1 extra root vnode reference (nullm_rootvp). */ |
| 217 | error = vflush(mp, 1, flags); |
| 218 | if (error) |
| 219 | return (error); |
| 220 | |
| 221 | /* |
| 222 | * Finally, throw away the null_mount structure |
| 223 | */ |
| 224 | mntdata = mp->mnt_data; |
| 225 | mp->mnt_data = 0; |
| 226 | free(mntdata, M_NULLFSMNT); |
| 227 | return 0; |
| 228 | } |
| 229 | |
| 230 | static int |
| 231 | nullfs_root(struct mount *mp, struct vnode **vpp) |
| 232 | { |
| 233 | struct thread *td = curthread; /* XXX */ |
| 234 | struct vnode *vp; |
| 235 | |
| 236 | NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, |
| 237 | (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, |
| 238 | (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); |
| 239 | |
| 240 | /* |
| 241 | * Return locked reference to root. |
| 242 | */ |
| 243 | vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; |
| 244 | vref(vp); |
| 245 | |
| 246 | #ifdef NULLFS_DEBUG |
| 247 | if (VOP_ISLOCKED(vp, NULL)) { |
| 248 | Debugger("root vnode is locked.\n"); |
| 249 | vrele(vp); |
| 250 | return (EDEADLK); |
| 251 | } |
| 252 | #endif |
| 253 | vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); |
| 254 | *vpp = vp; |
| 255 | return 0; |
| 256 | } |
| 257 | |
| 258 | static int |
| 259 | nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, |
| 260 | struct thread *td) |
| 261 | { |
| 262 | return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); |
| 263 | } |
| 264 | |
| 265 | static int |
| 266 | nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) |
| 267 | { |
| 268 | int error; |
| 269 | struct statfs mstat; |
| 270 | |
| 271 | NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, |
| 272 | (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, |
| 273 | (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); |
| 274 | |
| 275 | bzero(&mstat, sizeof(mstat)); |
| 276 | |
| 277 | error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); |
| 278 | if (error) |
| 279 | return (error); |
| 280 | |
| 281 | /* now copy across the "interesting" information and fake the rest */ |
| 282 | sbp->f_type = mstat.f_type; |
| 283 | sbp->f_flags = mstat.f_flags; |
| 284 | sbp->f_bsize = mstat.f_bsize; |
| 285 | sbp->f_iosize = mstat.f_iosize; |
| 286 | sbp->f_blocks = mstat.f_blocks; |
| 287 | sbp->f_bfree = mstat.f_bfree; |
| 288 | sbp->f_bavail = mstat.f_bavail; |
| 289 | sbp->f_files = mstat.f_files; |
| 290 | sbp->f_ffree = mstat.f_ffree; |
| 291 | if (sbp != &mp->mnt_stat) { |
| 292 | bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); |
| 293 | bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); |
| 294 | } |
| 295 | return (0); |
| 296 | } |
| 297 | |
| 298 | static int |
| 299 | nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) |
| 300 | { |
| 301 | |
| 302 | return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); |
| 303 | } |
| 304 | |
| 305 | static int |
| 306 | nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) |
| 307 | { |
| 308 | |
| 309 | return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); |
| 310 | } |
| 311 | |
| 312 | static int |
| 313 | nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, |
| 314 | struct ucred **credanonp) |
| 315 | { |
| 316 | |
| 317 | return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, |
| 318 | extflagsp, credanonp); |
| 319 | } |
| 320 | |
| 321 | static int |
| 322 | nullfs_vptofh(struct vnode *vp, struct fid *fhp) |
| 323 | { |
| 324 | return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); |
| 325 | } |
| 326 | |
| 327 | static int |
| 328 | nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, |
| 329 | struct thread *td) |
| 330 | { |
| 331 | return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, |
| 332 | arg, td); |
| 333 | } |
| 334 | |
| 335 | |
| 336 | static struct vfsops null_vfsops = { |
| 337 | .vfs_mount = nullfs_mount, |
| 338 | .vfs_unmount = nullfs_unmount, |
| 339 | .vfs_root = nullfs_root, |
| 340 | .vfs_quotactl = nullfs_quotactl, |
| 341 | .vfs_statfs = nullfs_statfs, |
| 342 | .vfs_sync = vfs_stdsync, |
| 343 | .vfs_vget = nullfs_vget, |
| 344 | .vfs_fhtovp = nullfs_fhtovp, |
| 345 | .vfs_checkexp = nullfs_checkexp, |
| 346 | .vfs_vptofh = nullfs_vptofh, |
| 347 | .vfs_init = nullfs_init, |
| 348 | .vfs_uninit = nullfs_uninit, |
| 349 | .vfs_extattrctl = nullfs_extattrctl |
| 350 | }; |
| 351 | |
| 352 | VFS_SET(null_vfsops, null, VFCF_LOOPBACK); |