1 /*- 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed 6 * to Berkeley by John Heidemann of the UCLA Ficus project. 7 * 8 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project 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 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)vfs_init.c 8.3 (Berkeley) 1/4/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/fnv_hash.h> 43 #include <sys/kernel.h> 44 #include <sys/linker.h> 45 #include <sys/mount.h> 46 #include <sys/proc.h> 47 #include <sys/syscallsubr.h> 48 #include <sys/sysctl.h> 49 #include <sys/vnode.h> 50 #include <sys/malloc.h> 51 52 static int vfs_register(struct vfsconf *); 53 static int vfs_unregister(struct vfsconf *); 54 55 MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes"); 56 57 /* 58 * The highest defined VFS number. 59 */ 60 int maxvfsconf = VFS_GENERIC + 1; 61 62 /* 63 * Single-linked list of configured VFSes. 64 * New entries are added/deleted by vfs_register()/vfs_unregister() 65 */ 66 struct vfsconfhead vfsconf = TAILQ_HEAD_INITIALIZER(vfsconf); 67 68 /* 69 * Loader.conf variable vfs.typenumhash enables setting vfc_typenum using a hash 70 * calculation on vfc_name, so that it doesn't change when file systems are 71 * loaded in a different order. This will avoid the NFS server file handles from 72 * changing for file systems that use vfc_typenum in their fsid. 73 */ 74 static int vfs_typenumhash = 1; 75 TUNABLE_INT("vfs.typenumhash", &vfs_typenumhash); 76 SYSCTL_INT(_vfs, OID_AUTO, typenumhash, CTLFLAG_RDTUN, &vfs_typenumhash, 0, 77 "Set vfc_typenum using a hash calculation on vfc_name, so that it does not" 78 "change when file systems are loaded in a different order."); 79 80 /* 81 * A Zen vnode attribute structure. 82 * 83 * Initialized when the first filesystem registers by vfs_register(). 84 */ 85 struct vattr va_null; 86 87 /* 88 * vfs_init.c 89 * 90 * Allocate and fill in operations vectors. 91 * 92 * An undocumented feature of this approach to defining operations is that 93 * there can be multiple entries in vfs_opv_descs for the same operations 94 * vector. This allows third parties to extend the set of operations 95 * supported by another layer in a binary compatibile way. For example, 96 * assume that NFS needed to be modified to support Ficus. NFS has an entry 97 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 98 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 99 * listing those new operations Ficus adds to NFS, all without modifying the 100 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 101 * that is a(whole)nother story.) This is a feature. 102 */ 103 104 /* 105 * Routines having to do with the management of the vnode table. 106 */ 107 108 struct vfsconf * 109 vfs_byname(const char *name) 110 { 111 struct vfsconf *vfsp; 112 113 if (!strcmp(name, "ffs")) 114 name = "ufs"; 115 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) 116 if (!strcmp(name, vfsp->vfc_name)) 117 return (vfsp); 118 return (NULL); 119 } 120 121 struct vfsconf * 122 vfs_byname_kld(const char *fstype, struct thread *td, int *error) 123 { 124 struct vfsconf *vfsp; 125 int fileid, loaded; 126 127 vfsp = vfs_byname(fstype); 128 if (vfsp != NULL) 129 return (vfsp); 130 131 /* Try to load the respective module. */ 132 *error = kern_kldload(td, fstype, &fileid); 133 loaded = (*error == 0); 134 if (*error == EEXIST) 135 *error = 0; 136 if (*error) 137 return (NULL); 138 139 /* Look up again to see if the VFS was loaded. */ 140 vfsp = vfs_byname(fstype); 141 if (vfsp == NULL) { 142 if (loaded) 143 (void)kern_kldunload(td, fileid, LINKER_UNLOAD_FORCE); 144 *error = ENODEV; 145 return (NULL); 146 } 147 return (vfsp); 148 } 149 150 151 /* Register a new filesystem type in the global table */ 152 static int 153 vfs_register(struct vfsconf *vfc) 154 { 155 struct sysctl_oid *oidp; 156 struct vfsops *vfsops; 157 static int once; 158 struct vfsconf *tvfc; 159 uint32_t hashval; 160 int secondpass; 161 162 if (!once) { 163 vattr_null(&va_null); 164 once = 1; 165 } 166 167 if (vfc->vfc_version != VFS_VERSION) { 168 printf("ERROR: filesystem %s, unsupported ABI version %x\n", 169 vfc->vfc_name, vfc->vfc_version); 170 return (EINVAL); 171 } 172 if (vfs_byname(vfc->vfc_name) != NULL) 173 return (EEXIST); 174 175 if (vfs_typenumhash != 0) { 176 /* 177 * Calculate a hash on vfc_name to use for vfc_typenum. Unless 178 * all of 1<->255 are assigned, it is limited to 8bits since 179 * that is what ZFS uses from vfc_typenum and is also the 180 * preferred range for vfs_getnewfsid(). 181 */ 182 hashval = fnv_32_str(vfc->vfc_name, FNV1_32_INIT); 183 hashval &= 0xff; 184 secondpass = 0; 185 do { 186 /* Look for and fix any collision. */ 187 TAILQ_FOREACH(tvfc, &vfsconf, vfc_list) { 188 if (hashval == tvfc->vfc_typenum) { 189 if (hashval == 255 && secondpass == 0) { 190 hashval = 1; 191 secondpass = 1; 192 } else 193 hashval++; 194 break; 195 } 196 } 197 } while (tvfc != NULL); 198 vfc->vfc_typenum = hashval; 199 if (vfc->vfc_typenum >= maxvfsconf) 200 maxvfsconf = vfc->vfc_typenum + 1; 201 } else 202 vfc->vfc_typenum = maxvfsconf++; 203 TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list); 204 205 /* 206 * If this filesystem has a sysctl node under vfs 207 * (i.e. vfs.xxfs), then change the oid number of that node to 208 * match the filesystem's type number. This allows user code 209 * which uses the type number to read sysctl variables defined 210 * by the filesystem to continue working. Since the oids are 211 * in a sorted list, we need to make sure the order is 212 * preserved by re-registering the oid after modifying its 213 * number. 214 */ 215 sysctl_lock(); 216 SLIST_FOREACH(oidp, &sysctl__vfs_children, oid_link) 217 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) { 218 sysctl_unregister_oid(oidp); 219 oidp->oid_number = vfc->vfc_typenum; 220 sysctl_register_oid(oidp); 221 break; 222 } 223 sysctl_unlock(); 224 225 /* 226 * Initialise unused ``struct vfsops'' fields, to use 227 * the vfs_std*() functions. Note, we need the mount 228 * and unmount operations, at the least. The check 229 * for vfsops available is just a debugging aid. 230 */ 231 KASSERT(vfc->vfc_vfsops != NULL, 232 ("Filesystem %s has no vfsops", vfc->vfc_name)); 233 /* 234 * Check the mount and unmount operations. 235 */ 236 vfsops = vfc->vfc_vfsops; 237 KASSERT(vfsops->vfs_mount != NULL, 238 ("Filesystem %s has no mount op", vfc->vfc_name)); 239 KASSERT(vfsops->vfs_unmount != NULL, 240 ("Filesystem %s has no unmount op", vfc->vfc_name)); 241 242 if (vfsops->vfs_root == NULL) 243 /* return file system's root vnode */ 244 vfsops->vfs_root = vfs_stdroot; 245 if (vfsops->vfs_quotactl == NULL) 246 /* quota control */ 247 vfsops->vfs_quotactl = vfs_stdquotactl; 248 if (vfsops->vfs_statfs == NULL) 249 /* return file system's status */ 250 vfsops->vfs_statfs = vfs_stdstatfs; 251 if (vfsops->vfs_sync == NULL) 252 /* 253 * flush unwritten data (nosync) 254 * file systems can use vfs_stdsync 255 * explicitly by setting it in the 256 * vfsop vector. 257 */ 258 vfsops->vfs_sync = vfs_stdnosync; 259 if (vfsops->vfs_vget == NULL) 260 /* convert an inode number to a vnode */ 261 vfsops->vfs_vget = vfs_stdvget; 262 if (vfsops->vfs_fhtovp == NULL) 263 /* turn an NFS file handle into a vnode */ 264 vfsops->vfs_fhtovp = vfs_stdfhtovp; 265 if (vfsops->vfs_checkexp == NULL) 266 /* check if file system is exported */ 267 vfsops->vfs_checkexp = vfs_stdcheckexp; 268 if (vfsops->vfs_init == NULL) 269 /* file system specific initialisation */ 270 vfsops->vfs_init = vfs_stdinit; 271 if (vfsops->vfs_uninit == NULL) 272 /* file system specific uninitialisation */ 273 vfsops->vfs_uninit = vfs_stduninit; 274 if (vfsops->vfs_extattrctl == NULL) 275 /* extended attribute control */ 276 vfsops->vfs_extattrctl = vfs_stdextattrctl; 277 if (vfsops->vfs_sysctl == NULL) 278 vfsops->vfs_sysctl = vfs_stdsysctl; 279 280 /* 281 * Call init function for this VFS... 282 */ 283 (*(vfc->vfc_vfsops->vfs_init))(vfc); 284 285 return 0; 286 } 287 288 289 /* Remove registration of a filesystem type */ 290 static int 291 vfs_unregister(struct vfsconf *vfc) 292 { 293 struct vfsconf *vfsp; 294 int error, i, maxtypenum; 295 296 i = vfc->vfc_typenum; 297 298 vfsp = vfs_byname(vfc->vfc_name); 299 if (vfsp == NULL) 300 return EINVAL; 301 if (vfsp->vfc_refcount) 302 return EBUSY; 303 if (vfc->vfc_vfsops->vfs_uninit != NULL) { 304 error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp); 305 if (error) 306 return (error); 307 } 308 TAILQ_REMOVE(&vfsconf, vfsp, vfc_list); 309 maxtypenum = VFS_GENERIC; 310 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) 311 if (maxtypenum < vfsp->vfc_typenum) 312 maxtypenum = vfsp->vfc_typenum; 313 maxvfsconf = maxtypenum + 1; 314 return 0; 315 } 316 317 /* 318 * Standard kernel module handling code for filesystem modules. 319 * Referenced from VFS_SET(). 320 */ 321 int 322 vfs_modevent(module_t mod, int type, void *data) 323 { 324 struct vfsconf *vfc; 325 int error = 0; 326 327 vfc = (struct vfsconf *)data; 328 329 switch (type) { 330 case MOD_LOAD: 331 if (vfc) 332 error = vfs_register(vfc); 333 break; 334 335 case MOD_UNLOAD: 336 if (vfc) 337 error = vfs_unregister(vfc); 338 break; 339 default: 340 error = EOPNOTSUPP; 341 break; 342 } 343 return (error); 344 } 345