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 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Efficient memory file system. 42 * 43 * tmpfs is a file system that uses NetBSD's virtual memory sub-system 44 * (the well-known UVM) to store file data and metadata in an efficient 45 * way. This means that it does not follow the structure of an on-disk 46 * file system because it simply does not need to. Instead, it uses 47 * memory-specific data structures and algorithms to automatically 48 * allocate and release resources. 49 */ 50 #include <sys/cdefs.h> 51 __FBSDID("$FreeBSD$"); 52 53 #include <sys/param.h> 54 #include <sys/limits.h> 55 #include <sys/lock.h> 56 #include <sys/mutex.h> 57 #include <sys/kernel.h> 58 #include <sys/stat.h> 59 #include <sys/systm.h> 60 #include <sys/sysctl.h> 61 62 #include <vm/vm.h> 63 #include <vm/vm_object.h> 64 #include <vm/vm_param.h> 65 66 #include <fs/tmpfs/tmpfs.h> 67 68 /* 69 * Default permission for root node 70 */ 71 #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) 72 73 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures"); 74 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names"); 75 76 /* --------------------------------------------------------------------- */ 77 78 static int tmpfs_mount(struct mount *, struct thread *); 79 static int tmpfs_unmount(struct mount *, int, struct thread *); 80 static int tmpfs_root(struct mount *, int flags, struct vnode **, 81 struct thread *); 82 static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **); 83 static int tmpfs_statfs(struct mount *, struct statfs *, struct thread *); 84 85 /* --------------------------------------------------------------------- */ 86 87 static const char *tmpfs_opts[] = { 88 "from", "size", "inodes", "uid", "gid", "mode", "export", 89 NULL 90 }; 91 92 /* --------------------------------------------------------------------- */ 93 94 #define SWI_MAXMIB 3 95 96 static u_int 97 get_swpgtotal(void) 98 { 99 struct xswdev xsd; 100 char *sname = "vm.swap_info"; 101 int soid[SWI_MAXMIB], oid[2]; 102 u_int unswdev, total, dmmax, nswapdev; 103 size_t mibi, len; 104 105 total = 0; 106 107 len = sizeof(dmmax); 108 if (kernel_sysctlbyname(curthread, "vm.dmmax", &dmmax, &len, 109 NULL, 0, NULL, 0) != 0) 110 return total; 111 112 len = sizeof(nswapdev); 113 if (kernel_sysctlbyname(curthread, "vm.nswapdev", 114 &nswapdev, &len, 115 NULL, 0, NULL, 0) != 0) 116 return total; 117 118 mibi = (SWI_MAXMIB - 1) * sizeof(int); 119 oid[0] = 0; 120 oid[1] = 3; 121 122 if (kernel_sysctl(curthread, oid, 2, 123 soid, &mibi, (void *)sname, strlen(sname), 124 NULL, 0) != 0) 125 return total; 126 127 mibi = (SWI_MAXMIB - 1); 128 for (unswdev = 0; unswdev < nswapdev; ++unswdev) { 129 soid[mibi] = unswdev; 130 len = sizeof(struct xswdev); 131 if (kernel_sysctl(curthread, 132 soid, mibi + 1, &xsd, &len, NULL, 0, 133 NULL, 0) != 0) 134 return total; 135 if (len == sizeof(struct xswdev)) 136 total += (xsd.xsw_nblks - dmmax); 137 } 138 139 /* Not Reached */ 140 return total; 141 } 142 143 /* --------------------------------------------------------------------- */ 144 static int 145 tmpfs_node_ctor(void *mem, int size, void *arg, int flags) 146 { 147 struct tmpfs_node *node = (struct tmpfs_node *)mem; 148 149 node->tn_gen++; 150 node->tn_size = 0; 151 node->tn_status = 0; 152 node->tn_flags = 0; 153 node->tn_links = 0; 154 node->tn_vnode = NULL; 155 node->tn_vpstate = 0; 156 157 return (0); 158 } 159 160 static void 161 tmpfs_node_dtor(void *mem, int size, void *arg) 162 { 163 struct tmpfs_node *node = (struct tmpfs_node *)mem; 164 node->tn_type = VNON; 165 } 166 167 static int 168 tmpfs_node_init(void *mem, int size, int flags) 169 { 170 struct tmpfs_node *node = (struct tmpfs_node *)mem; 171 node->tn_id = 0; 172 173 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF); 174 node->tn_gen = arc4random(); 175 176 return (0); 177 } 178 179 static void 180 tmpfs_node_fini(void *mem, int size) 181 { 182 struct tmpfs_node *node = (struct tmpfs_node *)mem; 183 184 mtx_destroy(&node->tn_interlock); 185 } 186 187 static int 188 tmpfs_mount(struct mount *mp, struct thread *td) 189 { 190 struct tmpfs_mount *tmp; 191 struct tmpfs_node *root; 192 size_t pages, mem_size; 193 ino_t nodes; 194 int error; 195 /* Size counters. */ 196 ino_t nodes_max; 197 size_t size_max; 198 199 /* Root node attributes. */ 200 uid_t root_uid; 201 gid_t root_gid; 202 mode_t root_mode; 203 204 struct vattr va; 205 206 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts)) 207 return (EINVAL); 208 209 if (mp->mnt_flag & MNT_UPDATE) { 210 /* XXX: There is no support yet to update file system 211 * settings. Should be added. */ 212 213 return EOPNOTSUPP; 214 } 215 216 printf("WARNING: TMPFS is considered to be a highly experimental " 217 "feature in FreeBSD.\n"); 218 219 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY); 220 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred, td); 221 VOP_UNLOCK(mp->mnt_vnodecovered, 0); 222 if (error) 223 return (error); 224 225 if (mp->mnt_cred->cr_ruid != 0 || 226 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1) 227 root_gid = va.va_gid; 228 if (mp->mnt_cred->cr_ruid != 0 || 229 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1) 230 root_uid = va.va_uid; 231 if (mp->mnt_cred->cr_ruid != 0 || 232 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1) 233 root_mode = va.va_mode; 234 if (vfs_scanopt(mp->mnt_optnew, "inodes", "%d", &nodes_max) != 1) 235 nodes_max = 0; 236 if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1) 237 size_max = 0; 238 239 /* Do not allow mounts if we do not have enough memory to preserve 240 * the minimum reserved pages. */ 241 mem_size = cnt.v_free_count + cnt.v_inactive_count + get_swpgtotal(); 242 mem_size -= mem_size > cnt.v_wire_count ? cnt.v_wire_count : mem_size; 243 if (mem_size < TMPFS_PAGES_RESERVED) 244 return ENOSPC; 245 246 /* Get the maximum number of memory pages this file system is 247 * allowed to use, based on the maximum size the user passed in 248 * the mount structure. A value of zero is treated as if the 249 * maximum available space was requested. */ 250 if (size_max < PAGE_SIZE || size_max >= SIZE_MAX) 251 pages = SIZE_MAX; 252 else 253 pages = howmany(size_max, PAGE_SIZE); 254 MPASS(pages > 0); 255 256 if (nodes_max <= 3) 257 nodes = 3 + pages * PAGE_SIZE / 1024; 258 else 259 nodes = nodes_max; 260 MPASS(nodes >= 3); 261 262 /* Allocate the tmpfs mount structure and fill it. */ 263 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount), 264 M_TMPFSMNT, M_WAITOK | M_ZERO); 265 266 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF); 267 tmp->tm_nodes_max = nodes; 268 tmp->tm_nodes_inuse = 0; 269 tmp->tm_maxfilesize = (u_int64_t)(cnt.v_page_count + get_swpgtotal()) * PAGE_SIZE; 270 LIST_INIT(&tmp->tm_nodes_used); 271 272 tmp->tm_pages_max = pages; 273 tmp->tm_pages_used = 0; 274 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock); 275 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent", 276 sizeof(struct tmpfs_dirent), 277 NULL, NULL, NULL, NULL, 278 UMA_ALIGN_PTR, 0); 279 tmp->tm_node_pool = uma_zcreate("TMPFS node", 280 sizeof(struct tmpfs_node), 281 tmpfs_node_ctor, tmpfs_node_dtor, 282 tmpfs_node_init, tmpfs_node_fini, 283 UMA_ALIGN_PTR, 0); 284 285 /* Allocate the root node. */ 286 error = tmpfs_alloc_node(tmp, VDIR, root_uid, 287 root_gid, root_mode & ALLPERMS, NULL, NULL, 288 VNOVAL, td, &root); 289 290 if (error != 0 || root == NULL) { 291 uma_zdestroy(tmp->tm_node_pool); 292 uma_zdestroy(tmp->tm_dirent_pool); 293 delete_unrhdr(tmp->tm_ino_unr); 294 free(tmp, M_TMPFSMNT); 295 return error; 296 } 297 KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id)); 298 tmp->tm_root = root; 299 300 MNT_ILOCK(mp); 301 mp->mnt_flag |= MNT_LOCAL; 302 mp->mnt_kern_flag |= MNTK_MPSAFE; 303 MNT_IUNLOCK(mp); 304 305 mp->mnt_data = tmp; 306 mp->mnt_stat.f_namemax = MAXNAMLEN; 307 vfs_getnewfsid(mp); 308 vfs_mountedfrom(mp, "tmpfs"); 309 310 return 0; 311 } 312 313 /* --------------------------------------------------------------------- */ 314 315 /* ARGSUSED2 */ 316 static int 317 tmpfs_unmount(struct mount *mp, int mntflags, struct thread *l) 318 { 319 int error; 320 int flags = 0; 321 struct tmpfs_mount *tmp; 322 struct tmpfs_node *node; 323 324 /* Handle forced unmounts. */ 325 if (mntflags & MNT_FORCE) 326 flags |= FORCECLOSE; 327 328 /* Finalize all pending I/O. */ 329 error = vflush(mp, 0, flags, l); 330 if (error != 0) 331 return error; 332 333 tmp = VFS_TO_TMPFS(mp); 334 335 /* Free all associated data. The loop iterates over the linked list 336 * we have containing all used nodes. For each of them that is 337 * a directory, we free all its directory entries. Note that after 338 * freeing a node, it will automatically go to the available list, 339 * so we will later have to iterate over it to release its items. */ 340 node = LIST_FIRST(&tmp->tm_nodes_used); 341 while (node != NULL) { 342 struct tmpfs_node *next; 343 344 if (node->tn_type == VDIR) { 345 struct tmpfs_dirent *de; 346 347 de = TAILQ_FIRST(&node->tn_dir.tn_dirhead); 348 while (de != NULL) { 349 struct tmpfs_dirent *nde; 350 351 nde = TAILQ_NEXT(de, td_entries); 352 tmpfs_free_dirent(tmp, de, FALSE); 353 de = nde; 354 node->tn_size -= sizeof(struct tmpfs_dirent); 355 } 356 } 357 358 next = LIST_NEXT(node, tn_entries); 359 tmpfs_free_node(tmp, node); 360 node = next; 361 } 362 363 uma_zdestroy(tmp->tm_dirent_pool); 364 uma_zdestroy(tmp->tm_node_pool); 365 delete_unrhdr(tmp->tm_ino_unr); 366 367 mtx_destroy(&tmp->allnode_lock); 368 MPASS(tmp->tm_pages_used == 0); 369 MPASS(tmp->tm_nodes_inuse == 0); 370 371 /* Throw away the tmpfs_mount structure. */ 372 free(mp->mnt_data, M_TMPFSMNT); 373 mp->mnt_data = NULL; 374 375 MNT_ILOCK(mp); 376 mp->mnt_flag &= ~MNT_LOCAL; 377 MNT_IUNLOCK(mp); 378 return 0; 379 } 380 381 /* --------------------------------------------------------------------- */ 382 383 static int 384 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td) 385 { 386 int error; 387 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp, td); 388 389 if (!error) 390 (*vpp)->v_vflag |= VV_ROOT; 391 392 return error; 393 } 394 395 /* --------------------------------------------------------------------- */ 396 397 static int 398 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp) 399 { 400 boolean_t found; 401 struct tmpfs_fid *tfhp; 402 struct tmpfs_mount *tmp; 403 struct tmpfs_node *node; 404 405 tmp = VFS_TO_TMPFS(mp); 406 407 tfhp = (struct tmpfs_fid *)fhp; 408 if (tfhp->tf_len != sizeof(struct tmpfs_fid)) 409 return EINVAL; 410 411 if (tfhp->tf_id >= tmp->tm_nodes_max) 412 return EINVAL; 413 414 found = FALSE; 415 416 TMPFS_LOCK(tmp); 417 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 418 if (node->tn_id == tfhp->tf_id && 419 node->tn_gen == tfhp->tf_gen) { 420 found = TRUE; 421 break; 422 } 423 } 424 TMPFS_UNLOCK(tmp); 425 426 if (found) 427 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp, curthread)); 428 429 return (EINVAL); 430 } 431 432 /* --------------------------------------------------------------------- */ 433 434 /* ARGSUSED2 */ 435 static int 436 tmpfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *l) 437 { 438 fsfilcnt_t freenodes; 439 struct tmpfs_mount *tmp; 440 441 tmp = VFS_TO_TMPFS(mp); 442 443 sbp->f_iosize = PAGE_SIZE; 444 sbp->f_bsize = PAGE_SIZE; 445 446 sbp->f_blocks = TMPFS_PAGES_MAX(tmp); 447 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp); 448 449 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse, 450 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node)); 451 452 sbp->f_files = freenodes + tmp->tm_nodes_inuse; 453 sbp->f_ffree = freenodes; 454 /* sbp->f_owner = tmp->tn_uid; */ 455 456 return 0; 457 } 458 459 /* --------------------------------------------------------------------- */ 460 461 /* 462 * tmpfs vfs operations. 463 */ 464 465 struct vfsops tmpfs_vfsops = { 466 .vfs_mount = tmpfs_mount, 467 .vfs_unmount = tmpfs_unmount, 468 .vfs_root = tmpfs_root, 469 .vfs_statfs = tmpfs_statfs, 470 .vfs_fhtovp = tmpfs_fhtovp, 471 }; 472 VFS_SET(tmpfs_vfsops, tmpfs, 0); 473