1/* $NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $ */ 2 3/*- 4 * Copyright (c) 2005 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Julio M. Merino Vidal, developed as part of Google's Summer of Code 9 * 2005 program. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33/* 34 * Efficient memory file system. 35 * 36 * tmpfs is a file system that uses NetBSD's virtual memory sub-system 37 * (the well-known UVM) to store file data and metadata in an efficient 38 * way. This means that it does not follow the structure of an on-disk 39 * file system because it simply does not need to. Instead, it uses 40 * memory-specific data structures and algorithms to automatically 41 * allocate and release resources. 42 */ 43#include <sys/cdefs.h> 44__FBSDID("$FreeBSD$"); 45 46#include <sys/param.h> 47#include <sys/limits.h> 48#include <sys/lock.h> 49#include <sys/mutex.h> 50#include <sys/proc.h> 51#include <sys/jail.h> 52#include <sys/kernel.h> 53#include <sys/stat.h> 54#include <sys/systm.h> 55#include <sys/sysctl.h> 56 57#include <vm/vm.h> 58#include <vm/vm_object.h> 59#include <vm/vm_param.h> 60 61#include <fs/tmpfs/tmpfs.h> 62 63/* 64 * Default permission for root node 65 */ 66#define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) 67 68MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures"); 69MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names"); 70 71/* --------------------------------------------------------------------- */ 72 73static int tmpfs_mount(struct mount *); 74static int tmpfs_unmount(struct mount *, int); 75static int tmpfs_root(struct mount *, int flags, struct vnode **); 76static int tmpfs_fhtovp(struct mount *, struct fid *, int, 77 struct vnode **); 78static int tmpfs_statfs(struct mount *, struct statfs *); 79 80/* --------------------------------------------------------------------- */ 81 82static const char *tmpfs_opts[] = { 83 "from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export", 84 "union", NULL 85}; 86 87static const char *tmpfs_updateopts[] = { 88 "from", "export", NULL 89}; 90 91/* --------------------------------------------------------------------- */ 92 93static int 94tmpfs_node_ctor(void *mem, int size, void *arg, int flags) 95{ 96 struct tmpfs_node *node = (struct tmpfs_node *)mem; 97 98 node->tn_gen++; 99 node->tn_size = 0; 100 node->tn_status = 0; 101 node->tn_flags = 0; 102 node->tn_links = 0; 103 node->tn_vnode = NULL; 104 node->tn_vpstate = 0; 105 106 return (0); 107} 108 109static void 110tmpfs_node_dtor(void *mem, int size, void *arg) 111{ 112 struct tmpfs_node *node = (struct tmpfs_node *)mem; 113 node->tn_type = VNON; 114} 115 116static int 117tmpfs_node_init(void *mem, int size, int flags) 118{ 119 struct tmpfs_node *node = (struct tmpfs_node *)mem; 120 node->tn_id = 0; 121 122 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF); 123 node->tn_gen = arc4random(); 124 125 return (0); 126} 127 128static void 129tmpfs_node_fini(void *mem, int size) 130{ 131 struct tmpfs_node *node = (struct tmpfs_node *)mem; 132 133 mtx_destroy(&node->tn_interlock); 134} 135 136static int 137tmpfs_mount(struct mount *mp) 138{ 139 const size_t nodes_per_page = howmany(PAGE_SIZE, 140 sizeof(struct tmpfs_dirent) + sizeof(struct tmpfs_node)); 141 struct tmpfs_mount *tmp; 142 struct tmpfs_node *root; 143 struct thread *td = curthread; 144 int error; 145 /* Size counters. */ 146 u_quad_t pages; 147 off_t nodes_max, size_max, maxfilesize; 148 149 /* Root node attributes. */ 150 uid_t root_uid; 151 gid_t root_gid; 152 mode_t root_mode; 153 154 struct vattr va; 155 156 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_TMPFS)) 157 return (EPERM); 158 159 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts)) 160 return (EINVAL); 161 162 if (mp->mnt_flag & MNT_UPDATE) { 163 /* Only support update mounts for certain options. */ 164 if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0) 165 return (EOPNOTSUPP); 166 if (vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) != 167 ((struct tmpfs_mount *)mp->mnt_data)->tm_ronly) 168 return (EOPNOTSUPP); 169 return (0); 170 } 171 172 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY); 173 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred); 174 VOP_UNLOCK(mp->mnt_vnodecovered, 0); 175 if (error) 176 return (error); 177 178 if (mp->mnt_cred->cr_ruid != 0 || 179 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1) 180 root_gid = va.va_gid; 181 if (mp->mnt_cred->cr_ruid != 0 || 182 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1) 183 root_uid = va.va_uid; 184 if (mp->mnt_cred->cr_ruid != 0 || 185 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1) 186 root_mode = va.va_mode; 187 if (vfs_getopt_size(mp->mnt_optnew, "inodes", &nodes_max) != 0) 188 nodes_max = 0; 189 if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) != 0) 190 size_max = 0; 191 if (vfs_getopt_size(mp->mnt_optnew, "maxfilesize", &maxfilesize) != 0) 192 maxfilesize = 0; 193 194 /* Do not allow mounts if we do not have enough memory to preserve 195 * the minimum reserved pages. */ 196 if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED) 197 return ENOSPC; 198 199 /* Get the maximum number of memory pages this file system is 200 * allowed to use, based on the maximum size the user passed in 201 * the mount structure. A value of zero is treated as if the 202 * maximum available space was requested. */ 203 if (size_max < PAGE_SIZE || size_max > OFF_MAX - PAGE_SIZE || 204 (SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX)) 205 pages = SIZE_MAX; 206 else 207 pages = howmany(size_max, PAGE_SIZE); 208 MPASS(pages > 0); 209 210 if (nodes_max <= 3) { 211 if (pages < INT_MAX / nodes_per_page) 212 nodes_max = pages * nodes_per_page; 213 else 214 nodes_max = INT_MAX; 215 } 216 if (nodes_max > INT_MAX) 217 nodes_max = INT_MAX; 218 MPASS(nodes_max >= 3); 219 220 /* Allocate the tmpfs mount structure and fill it. */ 221 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount), 222 M_TMPFSMNT, M_WAITOK | M_ZERO); 223 224 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF); 225 tmp->tm_nodes_max = nodes_max; 226 tmp->tm_nodes_inuse = 0; 227 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX; 228 LIST_INIT(&tmp->tm_nodes_used); 229 230 tmp->tm_pages_max = pages; 231 tmp->tm_pages_used = 0; 232 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock); 233 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent", 234 sizeof(struct tmpfs_dirent), 235 NULL, NULL, NULL, NULL, 236 UMA_ALIGN_PTR, 0); 237 tmp->tm_node_pool = uma_zcreate("TMPFS node", 238 sizeof(struct tmpfs_node), 239 tmpfs_node_ctor, tmpfs_node_dtor, 240 tmpfs_node_init, tmpfs_node_fini, 241 UMA_ALIGN_PTR, 0); 242 tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0; 243 244 /* Allocate the root node. */ 245 error = tmpfs_alloc_node(tmp, VDIR, root_uid, 246 root_gid, root_mode & ALLPERMS, NULL, NULL, 247 VNOVAL, &root); 248 249 if (error != 0 || root == NULL) { 250 uma_zdestroy(tmp->tm_node_pool); 251 uma_zdestroy(tmp->tm_dirent_pool); 252 delete_unrhdr(tmp->tm_ino_unr); 253 free(tmp, M_TMPFSMNT); 254 return error; 255 } 256 KASSERT(root->tn_id == 2, 257 ("tmpfs root with invalid ino: %ju", (uintmax_t)root->tn_id)); 258 tmp->tm_root = root; 259 260 MNT_ILOCK(mp); 261 mp->mnt_flag |= MNT_LOCAL; 262 MNT_IUNLOCK(mp); 263 264 mp->mnt_data = tmp; 265 mp->mnt_stat.f_namemax = MAXNAMLEN; 266 vfs_getnewfsid(mp); 267 vfs_mountedfrom(mp, "tmpfs"); 268 269 return 0; 270} 271 272/* --------------------------------------------------------------------- */ 273 274/* ARGSUSED2 */ 275static int 276tmpfs_unmount(struct mount *mp, int mntflags) 277{ 278 int error; 279 int flags = 0; 280 struct tmpfs_mount *tmp; 281 struct tmpfs_node *node; 282 283 /* Handle forced unmounts. */ 284 if (mntflags & MNT_FORCE) 285 flags |= FORCECLOSE; 286 287 /* Finalize all pending I/O. */ 288 error = vflush(mp, 0, flags, curthread); 289 if (error != 0) 290 return error; 291 292 tmp = VFS_TO_TMPFS(mp); 293 294 /* Free all associated data. The loop iterates over the linked list 295 * we have containing all used nodes. For each of them that is 296 * a directory, we free all its directory entries. Note that after 297 * freeing a node, it will automatically go to the available list, 298 * so we will later have to iterate over it to release its items. */ 299 node = LIST_FIRST(&tmp->tm_nodes_used); 300 while (node != NULL) { 301 struct tmpfs_node *next; 302 303 if (node->tn_type == VDIR) 304 tmpfs_dir_destroy(tmp, node); 305 306 next = LIST_NEXT(node, tn_entries); 307 tmpfs_free_node(tmp, node); 308 node = next; 309 } 310 311 uma_zdestroy(tmp->tm_dirent_pool); 312 uma_zdestroy(tmp->tm_node_pool); 313 delete_unrhdr(tmp->tm_ino_unr); 314 315 mtx_destroy(&tmp->allnode_lock); 316 MPASS(tmp->tm_pages_used == 0); 317 MPASS(tmp->tm_nodes_inuse == 0); 318 319 /* Throw away the tmpfs_mount structure. */ 320 free(mp->mnt_data, M_TMPFSMNT); 321 mp->mnt_data = NULL; 322 323 MNT_ILOCK(mp); 324 mp->mnt_flag &= ~MNT_LOCAL; 325 MNT_IUNLOCK(mp); 326 return 0; 327} 328 329/* --------------------------------------------------------------------- */ 330 331static int 332tmpfs_root(struct mount *mp, int flags, struct vnode **vpp) 333{ 334 int error; 335 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp); 336 337 if (!error) 338 (*vpp)->v_vflag |= VV_ROOT; 339 340 return error; 341} 342 343/* --------------------------------------------------------------------- */ 344 345static int 346tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, 347 struct vnode **vpp) 348{ 349 boolean_t found; 350 struct tmpfs_fid *tfhp; 351 struct tmpfs_mount *tmp; 352 struct tmpfs_node *node; 353 354 tmp = VFS_TO_TMPFS(mp); 355 356 tfhp = (struct tmpfs_fid *)fhp; 357 if (tfhp->tf_len != sizeof(struct tmpfs_fid)) 358 return EINVAL; 359 360 if (tfhp->tf_id >= tmp->tm_nodes_max) 361 return EINVAL; 362 363 found = FALSE; 364 365 TMPFS_LOCK(tmp); 366 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 367 if (node->tn_id == tfhp->tf_id && 368 node->tn_gen == tfhp->tf_gen) { 369 found = TRUE; 370 break; 371 } 372 } 373 TMPFS_UNLOCK(tmp); 374 375 if (found) 376 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp)); 377 378 return (EINVAL); 379} 380 381/* --------------------------------------------------------------------- */ 382 383/* ARGSUSED2 */ 384static int 385tmpfs_statfs(struct mount *mp, struct statfs *sbp) 386{ 387 struct tmpfs_mount *tmp; 388 size_t used; 389 390 tmp = VFS_TO_TMPFS(mp); 391 392 sbp->f_iosize = PAGE_SIZE; 393 sbp->f_bsize = PAGE_SIZE; 394 395 used = tmpfs_pages_used(tmp); 396 if (tmp->tm_pages_max != SIZE_MAX) 397 sbp->f_blocks = tmp->tm_pages_max; 398 else 399 sbp->f_blocks = used + tmpfs_mem_avail(); 400 if (sbp->f_blocks <= used) 401 sbp->f_bavail = 0; 402 else 403 sbp->f_bavail = sbp->f_blocks - used; 404 sbp->f_bfree = sbp->f_bavail; 405 used = tmp->tm_nodes_inuse; 406 sbp->f_files = tmp->tm_nodes_max; 407 if (sbp->f_files <= used) 408 sbp->f_ffree = 0; 409 else 410 sbp->f_ffree = sbp->f_files - used; 411 /* sbp->f_owner = tmp->tn_uid; */ 412 413 return 0; 414} 415 416/* --------------------------------------------------------------------- */ 417 418/* 419 * tmpfs vfs operations. 420 */ 421 422struct vfsops tmpfs_vfsops = { 423 .vfs_mount = tmpfs_mount, 424 .vfs_unmount = tmpfs_unmount, 425 .vfs_root = tmpfs_root, 426 .vfs_statfs = tmpfs_statfs, 427 .vfs_fhtovp = tmpfs_fhtovp, 428}; 429VFS_SET(tmpfs_vfsops, tmpfs, VFCF_JAIL); 430