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 1.19 2006/01/04 03:09:53 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_checkexp(struct mount *mp, struct sockaddr *nam, 63 int *extflagsp, struct ucred **credanonp); 64 static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 65 struct thread *td); 66 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 67 caddr_t arg, struct thread *td); 68 static int nullfs_root(struct mount *mp, struct vnode **vpp); 69 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 70 struct thread *td); 71 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 72 static int nullfs_extattrctl(struct mount *mp, int cmd, 73 const char *attrname, caddr_t arg, struct thread *td); 74 75 /* 76 * Mount null layer 77 */ 78 static int 79 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td) 80 { 81 int error = 0; 82 struct null_args args; 83 struct vnode *rootvp; 84 struct null_mount *xmp; 85 u_int size; 86 struct nlookupdata nd; 87 88 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 89 90 /* 91 * Update is a no-op 92 */ 93 if (mp->mnt_flag & MNT_UPDATE) { 94 return (EOPNOTSUPP); 95 } 96 97 /* 98 * Get argument 99 */ 100 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 101 if (error) 102 return (error); 103 104 /* 105 * Find lower node 106 */ 107 rootvp = NULL; 108 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW); 109 if (error == 0) 110 error = nlookup(&nd); 111 if (error == 0) { 112 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE, 113 &rootvp); 114 } 115 116 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 117 M_NULLFSMNT, M_WAITOK); /* XXX */ 118 119 /* 120 * Save reference to underlying FS 121 */ 122 /* 123 * As lite stacking enters the scene, the old way of doing this 124 * -- via the vnode -- is not good enough anymore... 125 */ 126 xmp->nullm_vfs = nd.nl_ncp->nc_mount; 127 nlookup_done(&nd); 128 129 vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops, 130 null_vnodeop_entries, 0); 131 132 VOP_UNLOCK(rootvp, 0, td); 133 134 /* 135 * Keep a held reference to the root vnode. 136 * It is vrele'd in nullfs_unmount. 137 */ 138 xmp->nullm_rootvp = rootvp; 139 /* 140 * XXX What's the proper safety condition for querying 141 * the underlying mount? Is this flag tuning necessary 142 * at all? 143 */ 144 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL) 145 mp->mnt_flag |= MNT_LOCAL; 146 mp->mnt_data = (qaddr_t) xmp; 147 vfs_getnewfsid(mp); 148 149 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 150 &size); 151 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 152 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 153 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 154 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname); 155 return (0); 156 } 157 158 /* 159 * Free reference to null layer 160 */ 161 static int 162 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 163 { 164 void *mntdata; 165 int flags = 0; 166 167 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 168 169 if (mntflags & MNT_FORCE) 170 flags |= FORCECLOSE; 171 172 /* 173 * Finally, throw away the null_mount structure 174 */ 175 mntdata = mp->mnt_data; 176 mp->mnt_data = 0; 177 free(mntdata, M_NULLFSMNT); 178 return 0; 179 } 180 181 static int 182 nullfs_root(struct mount *mp, struct vnode **vpp) 183 { 184 struct thread *td = curthread; /* XXX */ 185 struct vnode *vp; 186 187 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp, 188 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp); 189 190 /* 191 * Return locked reference to root. 192 */ 193 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 194 vref(vp); 195 196 #ifdef NULLFS_DEBUG 197 if (VOP_ISLOCKED(vp, NULL)) { 198 Debugger("root vnode is locked.\n"); 199 vrele(vp); 200 return (EDEADLK); 201 } 202 #endif 203 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 204 *vpp = vp; 205 return 0; 206 } 207 208 static int 209 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 210 struct thread *td) 211 { 212 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 213 } 214 215 static int 216 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 217 { 218 int error; 219 struct statfs mstat; 220 221 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp, 222 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp); 223 224 bzero(&mstat, sizeof(mstat)); 225 226 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 227 if (error) 228 return (error); 229 230 /* now copy across the "interesting" information and fake the rest */ 231 sbp->f_type = mstat.f_type; 232 sbp->f_flags = mstat.f_flags; 233 sbp->f_bsize = mstat.f_bsize; 234 sbp->f_iosize = mstat.f_iosize; 235 sbp->f_blocks = mstat.f_blocks; 236 sbp->f_bfree = mstat.f_bfree; 237 sbp->f_bavail = mstat.f_bavail; 238 sbp->f_files = mstat.f_files; 239 sbp->f_ffree = mstat.f_ffree; 240 if (sbp != &mp->mnt_stat) { 241 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 242 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 243 } 244 return (0); 245 } 246 247 static int 248 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 249 struct ucred **credanonp) 250 { 251 252 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 253 extflagsp, credanonp); 254 } 255 256 static int 257 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 258 struct thread *td) 259 { 260 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 261 arg, td); 262 } 263 264 265 static struct vfsops null_vfsops = { 266 .vfs_mount = nullfs_mount, 267 .vfs_unmount = nullfs_unmount, 268 .vfs_root = nullfs_root, 269 .vfs_quotactl = nullfs_quotactl, 270 .vfs_statfs = nullfs_statfs, 271 .vfs_sync = vfs_stdsync, 272 .vfs_checkexp = nullfs_checkexp, 273 .vfs_extattrctl = nullfs_extattrctl 274 }; 275 276 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 277