layer_vfsops.c revision 1.39
1 /* $NetBSD: layer_vfsops.c,v 1.39 2012/02/01 05:34:42 dholland Exp $ */ 2 3 /* 4 * Copyright (c) 1999 National Aeronautics & Space Administration 5 * All rights reserved. 6 * 7 * This software was written by William Studenmund of the 8 * Numerical Aerospace Simulation Facility, NASA Ames Research Center. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the National Aeronautics & Space Administration 19 * nor the names of its contributors may be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB- 27 * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 28 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /* 37 * Copyright (c) 1992, 1993, 1995 38 * The Regents of the University of California. All rights reserved. 39 * 40 * This code is derived from software donated to Berkeley by 41 * Jan-Simon Pendry. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp 68 * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 69 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 70 */ 71 72 /* 73 * Generic layer VFS operations. 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: layer_vfsops.c,v 1.39 2012/02/01 05:34:42 dholland Exp $"); 78 79 #include <sys/param.h> 80 #include <sys/sysctl.h> 81 #include <sys/systm.h> 82 #include <sys/vnode.h> 83 #include <sys/mount.h> 84 #include <sys/namei.h> 85 #include <sys/malloc.h> 86 #include <sys/kauth.h> 87 #include <sys/module.h> 88 89 #include <miscfs/genfs/layer.h> 90 #include <miscfs/genfs/layer_extern.h> 91 92 MODULE(MODULE_CLASS_MISC, layerfs, NULL); 93 94 static int 95 layerfs_modcmd(modcmd_t cmd, void *arg) 96 { 97 98 switch (cmd) { 99 case MODULE_CMD_INIT: 100 return 0; 101 case MODULE_CMD_FINI: 102 return 0; 103 default: 104 return ENOTTY; 105 } 106 return 0; 107 } 108 109 /* 110 * VFS start. Nothing needed here - the start routine on the underlying 111 * filesystem will have been called when that filesystem was mounted. 112 */ 113 int 114 layerfs_start(struct mount *mp, int flags) 115 { 116 117 #ifdef notyet 118 return VFS_START(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, flags); 119 #else 120 return 0; 121 #endif 122 } 123 124 int 125 layerfs_root(struct mount *mp, struct vnode **vpp) 126 { 127 struct vnode *vp; 128 129 vp = MOUNTTOLAYERMOUNT(mp)->layerm_rootvp; 130 if (vp == NULL) { 131 *vpp = NULL; 132 return EINVAL; 133 } 134 /* 135 * Return root vnode with locked and with a reference held. 136 */ 137 vref(vp); 138 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 139 *vpp = vp; 140 return 0; 141 } 142 143 int 144 layerfs_quotactl(struct mount *mp, struct quotactl_args *args) 145 { 146 147 return VFS_QUOTACTL(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, args); 148 } 149 150 int 151 layerfs_statvfs(struct mount *mp, struct statvfs *sbp) 152 { 153 struct statvfs *sbuf; 154 int error; 155 156 sbuf = kmem_zalloc(sizeof(*sbuf), KM_SLEEP); 157 if (sbuf == NULL) { 158 return ENOMEM; 159 } 160 error = VFS_STATVFS(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, sbuf); 161 if (error) { 162 goto done; 163 } 164 /* Copy across the relevant data and fake the rest. */ 165 sbp->f_flag = sbuf->f_flag; 166 sbp->f_bsize = sbuf->f_bsize; 167 sbp->f_frsize = sbuf->f_frsize; 168 sbp->f_iosize = sbuf->f_iosize; 169 sbp->f_blocks = sbuf->f_blocks; 170 sbp->f_bfree = sbuf->f_bfree; 171 sbp->f_bavail = sbuf->f_bavail; 172 sbp->f_bresvd = sbuf->f_bresvd; 173 sbp->f_files = sbuf->f_files; 174 sbp->f_ffree = sbuf->f_ffree; 175 sbp->f_favail = sbuf->f_favail; 176 sbp->f_fresvd = sbuf->f_fresvd; 177 sbp->f_namemax = sbuf->f_namemax; 178 copy_statvfs_info(sbp, mp); 179 done: 180 kmem_free(sbuf, sizeof(*sbuf)); 181 return error; 182 } 183 184 int 185 layerfs_sync(struct mount *mp, int waitfor, 186 kauth_cred_t cred) 187 { 188 189 /* 190 * XXX - Assumes no data cached at layer. 191 */ 192 return 0; 193 } 194 195 int 196 layerfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 197 { 198 struct vnode *vp; 199 int error; 200 201 error = VFS_VGET(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, ino, &vp); 202 if (error) { 203 *vpp = NULL; 204 return error; 205 } 206 error = layer_node_create(mp, vp, vpp); 207 if (error) { 208 vput(vp); 209 *vpp = NULL; 210 return error; 211 } 212 return 0; 213 } 214 215 int 216 layerfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 217 { 218 struct vnode *vp; 219 int error; 220 221 error = VFS_FHTOVP(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, fidp, &vp); 222 if (error) { 223 return error; 224 } 225 error = layer_node_create(mp, vp, vpp); 226 if (error) { 227 vput(vp); 228 *vpp = NULL; 229 return (error); 230 } 231 return 0; 232 } 233 234 int 235 layerfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 236 { 237 238 return VFS_VPTOFH(LAYERVPTOLOWERVP(vp), fhp, fh_size); 239 } 240 241 /* 242 * layerfs_snapshot - handle a snapshot through a layered file system 243 * 244 * At present, we do NOT support snapshotting through a layered file 245 * system as the ffs implementation changes v_vnlock of the snapshot 246 * vnodes to point to one common lock. As there is no way for us to 247 * absolutely pass this change up the stack, a layered file system 248 * would end up referencing the wrong lock. 249 * 250 * This routine serves as a central resource for this behavior; all 251 * layered file systems don't need to worry about the above. Also, if 252 * things get fixed, all layers get the benefit. 253 */ 254 int 255 layerfs_snapshot(struct mount *mp, struct vnode *vp, 256 struct timespec *ts) 257 { 258 259 return EOPNOTSUPP; 260 } 261 262 SYSCTL_SETUP(sysctl_vfs_layerfs_setup, "sysctl vfs.layerfs subtree setup") 263 { 264 const struct sysctlnode *layerfs_node = NULL; 265 266 sysctl_createv(clog, 0, NULL, NULL, 267 CTLFLAG_PERMANENT, 268 CTLTYPE_NODE, "vfs", NULL, 269 NULL, 0, NULL, 0, 270 CTL_VFS, CTL_EOL); 271 sysctl_createv(clog, 0, NULL, &layerfs_node, 272 CTLFLAG_PERMANENT, 273 CTLTYPE_NODE, "layerfs", 274 SYSCTL_DESCR("Generic layered file system"), 275 NULL, 0, NULL, 0, 276 CTL_VFS, CTL_CREATE); 277 278 #ifdef LAYERFS_DIAGNOSTIC 279 sysctl_createv(clog, 0, &layerfs_node, NULL, 280 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 281 CTLTYPE_INT, 282 "debug", 283 SYSCTL_DESCR("Verbose debugging messages"), 284 NULL, 0, &layerfs_debug, 0, 285 CTL_CREATE, CTL_EOL); 286 #endif 287 288 /* 289 * other subtrees should really be aliases to this, but since 290 * they can't tell if layerfs has been instantiated yet, they 291 * can't do that...not easily. not yet. :-) 292 */ 293 } 294 295 int 296 layerfs_renamelock_enter(struct mount *mp) 297 { 298 299 return VFS_RENAMELOCK_ENTER(MOUNTTOLAYERMOUNT(mp)->layerm_vfs); 300 } 301 302 void 303 layerfs_renamelock_exit(struct mount *mp) 304 { 305 306 VFS_RENAMELOCK_EXIT(MOUNTTOLAYERMOUNT(mp)->layerm_vfs); 307 } 308
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