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/kernel.h> 51 #include <sys/stat.h> 52 #include <sys/systm.h> 53 #include <sys/sysctl.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_object.h> 57 #include <vm/vm_param.h> 58 59 #include <fs/tmpfs/tmpfs.h> 60 61 /* 62 * Default permission for root node 63 */ 64 #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) 65 66 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures"); 67 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names"); 68 69 /* --------------------------------------------------------------------- */ 70 71 static int tmpfs_mount(struct mount *); 72 static int tmpfs_unmount(struct mount *, int); 73 static int tmpfs_root(struct mount *, int flags, struct vnode **); 74 static int tmpfs_fhtovp(struct mount *, struct fid *, int, 75 struct vnode **); 76 static int tmpfs_statfs(struct mount *, struct statfs *); 77 78 /* --------------------------------------------------------------------- */ 79 80 static const char *tmpfs_opts[] = { 81 "from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export", 82 "union", NULL 83 }; 84 85 static const char *tmpfs_updateopts[] = { 86 "from", "export", NULL 87 }; 88 89 /* --------------------------------------------------------------------- */ 90 91 static int 92 tmpfs_node_ctor(void *mem, int size, void *arg, int flags) 93 { 94 struct tmpfs_node *node = (struct tmpfs_node *)mem; 95 96 node->tn_gen++; 97 node->tn_size = 0; 98 node->tn_status = 0; 99 node->tn_flags = 0; 100 node->tn_links = 0; 101 node->tn_vnode = NULL; 102 node->tn_vpstate = 0; 103 104 return (0); 105 } 106 107 static void 108 tmpfs_node_dtor(void *mem, int size, void *arg) 109 { 110 struct tmpfs_node *node = (struct tmpfs_node *)mem; 111 node->tn_type = VNON; 112 } 113 114 static int 115 tmpfs_node_init(void *mem, int size, int flags) 116 { 117 struct tmpfs_node *node = (struct tmpfs_node *)mem; 118 node->tn_id = 0; 119 120 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF); 121 node->tn_gen = arc4random(); 122 123 return (0); 124 } 125 126 static void 127 tmpfs_node_fini(void *mem, int size) 128 { 129 struct tmpfs_node *node = (struct tmpfs_node *)mem; 130 131 mtx_destroy(&node->tn_interlock); 132 } 133 134 static int 135 tmpfs_mount(struct mount *mp) 136 { 137 const size_t nodes_per_page = howmany(PAGE_SIZE, 138 sizeof(struct tmpfs_dirent) + sizeof(struct tmpfs_node)); 139 struct tmpfs_mount *tmp; 140 struct tmpfs_node *root; 141 int error; 142 /* Size counters. */ 143 u_quad_t pages; 144 off_t nodes_max, size_max, maxfilesize; 145 146 /* Root node attributes. */ 147 uid_t root_uid; 148 gid_t root_gid; 149 mode_t root_mode; 150 151 struct vattr va; 152 153 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts)) 154 return (EINVAL); 155 156 if (mp->mnt_flag & MNT_UPDATE) { 157 /* Only support update mounts for certain options. */ 158 if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0) 159 return (EOPNOTSUPP); 160 if (vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) != 161 ((struct tmpfs_mount *)mp->mnt_data)->tm_ronly) 162 return (EOPNOTSUPP); 163 return (0); 164 } 165 166 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY); 167 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred); 168 VOP_UNLOCK(mp->mnt_vnodecovered, 0); 169 if (error) 170 return (error); 171 172 if (mp->mnt_cred->cr_ruid != 0 || 173 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1) 174 root_gid = va.va_gid; 175 if (mp->mnt_cred->cr_ruid != 0 || 176 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1) 177 root_uid = va.va_uid; 178 if (mp->mnt_cred->cr_ruid != 0 || 179 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1) 180 root_mode = va.va_mode; 181 if (vfs_getopt_size(mp->mnt_optnew, "inodes", &nodes_max) != 0) 182 nodes_max = 0; 183 if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) != 0) 184 size_max = 0; 185 if (vfs_getopt_size(mp->mnt_optnew, "maxfilesize", &maxfilesize) != 0) 186 maxfilesize = 0; 187 188 /* Do not allow mounts if we do not have enough memory to preserve 189 * the minimum reserved pages. */ 190 if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED) 191 return ENOSPC; 192 193 /* Get the maximum number of memory pages this file system is 194 * allowed to use, based on the maximum size the user passed in 195 * the mount structure. A value of zero is treated as if the 196 * maximum available space was requested. */ 197 if (size_max < PAGE_SIZE || size_max > OFF_MAX - PAGE_SIZE || 198 (SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX)) 199 pages = SIZE_MAX; 200 else 201 pages = howmany(size_max, PAGE_SIZE); 202 MPASS(pages > 0); 203 204 if (nodes_max <= 3) { 205 if (pages < INT_MAX / nodes_per_page) 206 nodes_max = pages * nodes_per_page; 207 else 208 nodes_max = INT_MAX; 209 } 210 if (nodes_max > INT_MAX) 211 nodes_max = INT_MAX; 212 MPASS(nodes_max >= 3); 213 214 /* Allocate the tmpfs mount structure and fill it. */ 215 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount), 216 M_TMPFSMNT, M_WAITOK | M_ZERO); 217 218 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF); 219 tmp->tm_nodes_max = nodes_max; 220 tmp->tm_nodes_inuse = 0; 221 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX; 222 LIST_INIT(&tmp->tm_nodes_used); 223 224 tmp->tm_pages_max = pages; 225 tmp->tm_pages_used = 0; 226 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock); 227 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent", 228 sizeof(struct tmpfs_dirent), 229 NULL, NULL, NULL, NULL, 230 UMA_ALIGN_PTR, 0); 231 tmp->tm_node_pool = uma_zcreate("TMPFS node", 232 sizeof(struct tmpfs_node), 233 tmpfs_node_ctor, tmpfs_node_dtor, 234 tmpfs_node_init, tmpfs_node_fini, 235 UMA_ALIGN_PTR, 0); 236 tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0; 237 238 /* Allocate the root node. */ 239 error = tmpfs_alloc_node(tmp, VDIR, root_uid, 240 root_gid, root_mode & ALLPERMS, NULL, NULL, 241 VNOVAL, &root); 242 243 if (error != 0 || root == NULL) { 244 uma_zdestroy(tmp->tm_node_pool); 245 uma_zdestroy(tmp->tm_dirent_pool); 246 delete_unrhdr(tmp->tm_ino_unr); 247 free(tmp, M_TMPFSMNT); 248 return error; 249 } 250 KASSERT(root->tn_id == 2, 251 ("tmpfs root with invalid ino: %ju", (uintmax_t)root->tn_id)); 252 tmp->tm_root = root; 253 254 MNT_ILOCK(mp); 255 mp->mnt_flag |= MNT_LOCAL; 256 MNT_IUNLOCK(mp); 257 258 mp->mnt_data = tmp; 259 mp->mnt_stat.f_namemax = MAXNAMLEN; 260 vfs_getnewfsid(mp); 261 vfs_mountedfrom(mp, "tmpfs"); 262 263 return 0; 264 } 265 266 /* --------------------------------------------------------------------- */ 267 268 /* ARGSUSED2 */ 269 static int 270 tmpfs_unmount(struct mount *mp, int mntflags) 271 { 272 int error; 273 int flags = 0; 274 struct tmpfs_mount *tmp; 275 struct tmpfs_node *node; 276 277 /* Handle forced unmounts. */ 278 if (mntflags & MNT_FORCE) 279 flags |= FORCECLOSE; 280 281 /* Finalize all pending I/O. */ 282 error = vflush(mp, 0, flags, curthread); 283 if (error != 0) 284 return error; 285 286 tmp = VFS_TO_TMPFS(mp); 287 288 /* Free all associated data. The loop iterates over the linked list 289 * we have containing all used nodes. For each of them that is 290 * a directory, we free all its directory entries. Note that after 291 * freeing a node, it will automatically go to the available list, 292 * so we will later have to iterate over it to release its items. */ 293 node = LIST_FIRST(&tmp->tm_nodes_used); 294 while (node != NULL) { 295 struct tmpfs_node *next; 296 297 if (node->tn_type == VDIR) 298 tmpfs_dir_destroy(tmp, node); 299 300 next = LIST_NEXT(node, tn_entries); 301 tmpfs_free_node(tmp, node); 302 node = next; 303 } 304 305 uma_zdestroy(tmp->tm_dirent_pool); 306 uma_zdestroy(tmp->tm_node_pool); 307 delete_unrhdr(tmp->tm_ino_unr); 308 309 mtx_destroy(&tmp->allnode_lock); 310 MPASS(tmp->tm_pages_used == 0); 311 MPASS(tmp->tm_nodes_inuse == 0); 312 313 /* Throw away the tmpfs_mount structure. */ 314 free(mp->mnt_data, M_TMPFSMNT); 315 mp->mnt_data = NULL; 316 317 MNT_ILOCK(mp); 318 mp->mnt_flag &= ~MNT_LOCAL; 319 MNT_IUNLOCK(mp); 320 return 0; 321 } 322 323 /* --------------------------------------------------------------------- */ 324 325 static int 326 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp) 327 { 328 int error; 329 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp); 330 331 if (!error) 332 (*vpp)->v_vflag |= VV_ROOT; 333 334 return error; 335 } 336 337 /* --------------------------------------------------------------------- */ 338 339 static int 340 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, 341 struct vnode **vpp) 342 { 343 boolean_t found; 344 struct tmpfs_fid *tfhp; 345 struct tmpfs_mount *tmp; 346 struct tmpfs_node *node; 347 348 tmp = VFS_TO_TMPFS(mp); 349 350 tfhp = (struct tmpfs_fid *)fhp; 351 if (tfhp->tf_len != sizeof(struct tmpfs_fid)) 352 return EINVAL; 353 354 if (tfhp->tf_id >= tmp->tm_nodes_max) 355 return EINVAL; 356 357 found = FALSE; 358 359 TMPFS_LOCK(tmp); 360 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 361 if (node->tn_id == tfhp->tf_id && 362 node->tn_gen == tfhp->tf_gen) { 363 found = TRUE; 364 break; 365 } 366 } 367 TMPFS_UNLOCK(tmp); 368 369 if (found) 370 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp)); 371 372 return (EINVAL); 373 } 374 375 /* --------------------------------------------------------------------- */ 376 377 /* ARGSUSED2 */ 378 static int 379 tmpfs_statfs(struct mount *mp, struct statfs *sbp) 380 { 381 struct tmpfs_mount *tmp; 382 size_t used; 383 384 tmp = VFS_TO_TMPFS(mp); 385 386 sbp->f_iosize = PAGE_SIZE; 387 sbp->f_bsize = PAGE_SIZE; 388 389 used = tmpfs_pages_used(tmp); 390 if (tmp->tm_pages_max != SIZE_MAX) 391 sbp->f_blocks = tmp->tm_pages_max; 392 else 393 sbp->f_blocks = used + tmpfs_mem_avail(); 394 if (sbp->f_blocks <= used) 395 sbp->f_bavail = 0; 396 else 397 sbp->f_bavail = sbp->f_blocks - used; 398 sbp->f_bfree = sbp->f_bavail; 399 used = tmp->tm_nodes_inuse; 400 sbp->f_files = tmp->tm_nodes_max; 401 if (sbp->f_files <= used) 402 sbp->f_ffree = 0; 403 else 404 sbp->f_ffree = sbp->f_files - used; 405 /* sbp->f_owner = tmp->tn_uid; */ 406 407 return 0; 408 } 409 410 /* --------------------------------------------------------------------- */ 411 412 /* 413 * tmpfs vfs operations. 414 */ 415 416 struct vfsops tmpfs_vfsops = { 417 .vfs_mount = tmpfs_mount, 418 .vfs_unmount = tmpfs_unmount, 419 .vfs_root = tmpfs_root, 420 .vfs_statfs = tmpfs_statfs, 421 .vfs_fhtovp = tmpfs_fhtovp, 422 }; 423 VFS_SET(tmpfs_vfsops, tmpfs, 0); 424