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 1.26 2006/09/05 03:48:13 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 vop_ops null_vnode_vops; 59 60 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 61 62 static int nullfs_root(struct mount *mp, struct vnode **vpp); 63 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 64 struct ucred *cred); 65 66 /* 67 * Mount null layer 68 */ 69 static int 70 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred) 71 { 72 int error = 0; 73 struct null_args args; 74 struct vnode *rootvp; 75 struct null_mount *xmp; 76 u_int size; 77 struct nlookupdata nd; 78 79 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 80 81 /* 82 * Update is a no-op 83 */ 84 if (mp->mnt_flag & MNT_UPDATE) { 85 return (EOPNOTSUPP); 86 } 87 88 /* 89 * Get argument 90 */ 91 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 92 if (error) 93 return (error); 94 95 /* 96 * Find lower node 97 */ 98 rootvp = NULL; 99 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW); 100 if (error == 0) 101 error = nlookup(&nd); 102 if (error == 0) { 103 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE, 104 &rootvp); 105 } 106 107 xmp = (struct null_mount *) kmalloc(sizeof(struct null_mount), 108 M_NULLFSMNT, M_WAITOK); /* XXX */ 109 110 /* 111 * Save reference to underlying FS 112 */ 113 /* 114 * As lite stacking enters the scene, the old way of doing this 115 * -- via the vnode -- is not good enough anymore... 116 */ 117 xmp->nullm_vfs = nd.nl_ncp->nc_mount; 118 nlookup_done(&nd); 119 120 vfs_add_vnodeops(mp, &null_vnode_vops, &mp->mnt_vn_norm_ops); 121 122 vn_unlock(rootvp); 123 124 /* 125 * Keep a held reference to the root vnode. 126 * It is vrele'd in nullfs_unmount. 127 */ 128 xmp->nullm_rootvp = rootvp; 129 /* 130 * XXX What's the proper safety condition for querying 131 * the underlying mount? Is this flag tuning necessary 132 * at all? 133 */ 134 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL) 135 mp->mnt_flag |= MNT_LOCAL; 136 mp->mnt_data = (qaddr_t) xmp; 137 vfs_getnewfsid(mp); 138 139 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 140 &size); 141 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 142 (void)nullfs_statfs(mp, &mp->mnt_stat, cred); 143 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 144 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname); 145 return (0); 146 } 147 148 /* 149 * Free reference to null layer 150 */ 151 static int 152 nullfs_unmount(struct mount *mp, int mntflags) 153 { 154 void *mntdata; 155 int flags = 0; 156 157 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 158 159 if (mntflags & MNT_FORCE) 160 flags |= FORCECLOSE; 161 162 /* 163 * Finally, throw away the null_mount structure 164 */ 165 mntdata = mp->mnt_data; 166 mp->mnt_data = 0; 167 kfree(mntdata, M_NULLFSMNT); 168 return 0; 169 } 170 171 static int 172 nullfs_root(struct mount *mp, struct vnode **vpp) 173 { 174 struct vnode *vp; 175 int error; 176 177 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp, 178 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp); 179 180 /* 181 * Return locked reference to root. 182 */ 183 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 184 error = vget(vp, LK_EXCLUSIVE | LK_RETRY); 185 if (error == 0) 186 *vpp = vp; 187 return (error); 188 } 189 190 static int 191 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 192 struct ucred *cred) 193 { 194 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, cred); 195 } 196 197 static int 198 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred) 199 { 200 int error; 201 struct statfs mstat; 202 203 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp, 204 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp); 205 206 bzero(&mstat, sizeof(mstat)); 207 208 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, cred); 209 if (error) 210 return (error); 211 212 /* now copy across the "interesting" information and fake the rest */ 213 sbp->f_type = mstat.f_type; 214 sbp->f_flags = mstat.f_flags; 215 sbp->f_bsize = mstat.f_bsize; 216 sbp->f_iosize = mstat.f_iosize; 217 sbp->f_blocks = mstat.f_blocks; 218 sbp->f_bfree = mstat.f_bfree; 219 sbp->f_bavail = mstat.f_bavail; 220 sbp->f_files = mstat.f_files; 221 sbp->f_ffree = mstat.f_ffree; 222 if (sbp != &mp->mnt_stat) { 223 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 224 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 225 } 226 return (0); 227 } 228 229 static int 230 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 231 struct ucred **credanonp) 232 { 233 234 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 235 extflagsp, credanonp); 236 } 237 238 static int 239 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 240 struct ucred *cred) 241 { 242 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 243 arg, cred); 244 } 245 246 247 static struct vfsops null_vfsops = { 248 .vfs_mount = nullfs_mount, 249 .vfs_unmount = nullfs_unmount, 250 .vfs_root = nullfs_root, 251 .vfs_quotactl = nullfs_quotactl, 252 .vfs_statfs = nullfs_statfs, 253 .vfs_sync = vfs_stdsync, 254 .vfs_checkexp = nullfs_checkexp, 255 .vfs_extattrctl = nullfs_extattrctl 256 }; 257 258 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 259