tmpfs_vfsops.c revision 263943
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: stable/10/sys/fs/tmpfs/tmpfs_vfsops.c 263943 2014-03-30 16:51:12Z bdrewery $"); 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 == 0 || size_max > OFF_MAX - PAGE_SIZE || 204 (SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX)) 205 pages = SIZE_MAX; 206 else { 207 size_max = roundup(size_max, PAGE_SIZE); 208 pages = howmany(size_max, PAGE_SIZE); 209 } 210 MPASS(pages > 0); 211 212 if (nodes_max <= 3) { 213 if (pages < INT_MAX / nodes_per_page) 214 nodes_max = pages * nodes_per_page; 215 else 216 nodes_max = INT_MAX; 217 } 218 if (nodes_max > INT_MAX) 219 nodes_max = INT_MAX; 220 MPASS(nodes_max >= 3); 221 222 /* Allocate the tmpfs mount structure and fill it. */ 223 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount), 224 M_TMPFSMNT, M_WAITOK | M_ZERO); 225 226 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF); 227 tmp->tm_nodes_max = nodes_max; 228 tmp->tm_nodes_inuse = 0; 229 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX; 230 LIST_INIT(&tmp->tm_nodes_used); 231 232 tmp->tm_pages_max = pages; 233 tmp->tm_pages_used = 0; 234 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock); 235 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent", 236 sizeof(struct tmpfs_dirent), 237 NULL, NULL, NULL, NULL, 238 UMA_ALIGN_PTR, 0); 239 tmp->tm_node_pool = uma_zcreate("TMPFS node", 240 sizeof(struct tmpfs_node), 241 tmpfs_node_ctor, tmpfs_node_dtor, 242 tmpfs_node_init, tmpfs_node_fini, 243 UMA_ALIGN_PTR, 0); 244 tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0; 245 246 /* Allocate the root node. */ 247 error = tmpfs_alloc_node(tmp, VDIR, root_uid, 248 root_gid, root_mode & ALLPERMS, NULL, NULL, 249 VNOVAL, &root); 250 251 if (error != 0 || root == NULL) { 252 uma_zdestroy(tmp->tm_node_pool); 253 uma_zdestroy(tmp->tm_dirent_pool); 254 delete_unrhdr(tmp->tm_ino_unr); 255 free(tmp, M_TMPFSMNT); 256 return error; 257 } 258 KASSERT(root->tn_id == 2, 259 ("tmpfs root with invalid ino: %ju", (uintmax_t)root->tn_id)); 260 tmp->tm_root = root; 261 262 MNT_ILOCK(mp); 263 mp->mnt_flag |= MNT_LOCAL; 264 MNT_IUNLOCK(mp); 265 266 mp->mnt_data = tmp; 267 mp->mnt_stat.f_namemax = MAXNAMLEN; 268 vfs_getnewfsid(mp); 269 vfs_mountedfrom(mp, "tmpfs"); 270 271 return 0; 272} 273 274/* --------------------------------------------------------------------- */ 275 276/* ARGSUSED2 */ 277static int 278tmpfs_unmount(struct mount *mp, int mntflags) 279{ 280 int error; 281 int flags = 0; 282 struct tmpfs_mount *tmp; 283 struct tmpfs_node *node; 284 285 /* Handle forced unmounts. */ 286 if (mntflags & MNT_FORCE) 287 flags |= FORCECLOSE; 288 289 /* Finalize all pending I/O. */ 290 error = vflush(mp, 0, flags, curthread); 291 if (error != 0) 292 return error; 293 294 tmp = VFS_TO_TMPFS(mp); 295 296 /* Free all associated data. The loop iterates over the linked list 297 * we have containing all used nodes. For each of them that is 298 * a directory, we free all its directory entries. Note that after 299 * freeing a node, it will automatically go to the available list, 300 * so we will later have to iterate over it to release its items. */ 301 node = LIST_FIRST(&tmp->tm_nodes_used); 302 while (node != NULL) { 303 struct tmpfs_node *next; 304 305 if (node->tn_type == VDIR) 306 tmpfs_dir_destroy(tmp, node); 307 308 next = LIST_NEXT(node, tn_entries); 309 tmpfs_free_node(tmp, node); 310 node = next; 311 } 312 313 uma_zdestroy(tmp->tm_dirent_pool); 314 uma_zdestroy(tmp->tm_node_pool); 315 delete_unrhdr(tmp->tm_ino_unr); 316 317 mtx_destroy(&tmp->allnode_lock); 318 MPASS(tmp->tm_pages_used == 0); 319 MPASS(tmp->tm_nodes_inuse == 0); 320 321 /* Throw away the tmpfs_mount structure. */ 322 free(mp->mnt_data, M_TMPFSMNT); 323 mp->mnt_data = NULL; 324 325 MNT_ILOCK(mp); 326 mp->mnt_flag &= ~MNT_LOCAL; 327 MNT_IUNLOCK(mp); 328 return 0; 329} 330 331/* --------------------------------------------------------------------- */ 332 333static int 334tmpfs_root(struct mount *mp, int flags, struct vnode **vpp) 335{ 336 int error; 337 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp); 338 339 if (!error) 340 (*vpp)->v_vflag |= VV_ROOT; 341 342 return error; 343} 344 345/* --------------------------------------------------------------------- */ 346 347static int 348tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, 349 struct vnode **vpp) 350{ 351 boolean_t found; 352 struct tmpfs_fid *tfhp; 353 struct tmpfs_mount *tmp; 354 struct tmpfs_node *node; 355 356 tmp = VFS_TO_TMPFS(mp); 357 358 tfhp = (struct tmpfs_fid *)fhp; 359 if (tfhp->tf_len != sizeof(struct tmpfs_fid)) 360 return EINVAL; 361 362 if (tfhp->tf_id >= tmp->tm_nodes_max) 363 return EINVAL; 364 365 found = FALSE; 366 367 TMPFS_LOCK(tmp); 368 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 369 if (node->tn_id == tfhp->tf_id && 370 node->tn_gen == tfhp->tf_gen) { 371 found = TRUE; 372 break; 373 } 374 } 375 TMPFS_UNLOCK(tmp); 376 377 if (found) 378 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp)); 379 380 return (EINVAL); 381} 382 383/* --------------------------------------------------------------------- */ 384 385/* ARGSUSED2 */ 386static int 387tmpfs_statfs(struct mount *mp, struct statfs *sbp) 388{ 389 struct tmpfs_mount *tmp; 390 size_t used; 391 392 tmp = VFS_TO_TMPFS(mp); 393 394 sbp->f_iosize = PAGE_SIZE; 395 sbp->f_bsize = PAGE_SIZE; 396 397 used = tmpfs_pages_used(tmp); 398 if (tmp->tm_pages_max != SIZE_MAX) 399 sbp->f_blocks = tmp->tm_pages_max; 400 else 401 sbp->f_blocks = used + tmpfs_mem_avail(); 402 if (sbp->f_blocks <= used) 403 sbp->f_bavail = 0; 404 else 405 sbp->f_bavail = sbp->f_blocks - used; 406 sbp->f_bfree = sbp->f_bavail; 407 used = tmp->tm_nodes_inuse; 408 sbp->f_files = tmp->tm_nodes_max; 409 if (sbp->f_files <= used) 410 sbp->f_ffree = 0; 411 else 412 sbp->f_ffree = sbp->f_files - used; 413 /* sbp->f_owner = tmp->tn_uid; */ 414 415 return 0; 416} 417 418/* --------------------------------------------------------------------- */ 419 420/* 421 * tmpfs vfs operations. 422 */ 423 424struct vfsops tmpfs_vfsops = { 425 .vfs_mount = tmpfs_mount, 426 .vfs_unmount = tmpfs_unmount, 427 .vfs_root = tmpfs_root, 428 .vfs_statfs = tmpfs_statfs, 429 .vfs_fhtovp = tmpfs_fhtovp, 430}; 431VFS_SET(tmpfs_vfsops, tmpfs, VFCF_JAIL); 432