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 NULL 83 }; 84 85 /* --------------------------------------------------------------------- */ 86 87 static int 88 tmpfs_node_ctor(void *mem, int size, void *arg, int flags) 89 { 90 struct tmpfs_node *node = (struct tmpfs_node *)mem; 91 92 node->tn_gen++; 93 node->tn_size = 0; 94 node->tn_status = 0; 95 node->tn_flags = 0; 96 node->tn_links = 0; 97 node->tn_vnode = NULL; 98 node->tn_vpstate = 0; 99 100 return (0); 101 } 102 103 static void 104 tmpfs_node_dtor(void *mem, int size, void *arg) 105 { 106 struct tmpfs_node *node = (struct tmpfs_node *)mem; 107 node->tn_type = VNON; 108 } 109 110 static int 111 tmpfs_node_init(void *mem, int size, int flags) 112 { 113 struct tmpfs_node *node = (struct tmpfs_node *)mem; 114 node->tn_id = 0; 115 116 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF); 117 node->tn_gen = arc4random(); 118 119 return (0); 120 } 121 122 static void 123 tmpfs_node_fini(void *mem, int size) 124 { 125 struct tmpfs_node *node = (struct tmpfs_node *)mem; 126 127 mtx_destroy(&node->tn_interlock); 128 } 129 130 static int 131 tmpfs_mount(struct mount *mp) 132 { 133 struct tmpfs_mount *tmp; 134 struct tmpfs_node *root; 135 size_t pages; 136 uint32_t nodes; 137 int error; 138 /* Size counters. */ 139 u_int nodes_max; 140 u_quad_t size_max, maxfilesize; 141 142 /* Root node attributes. */ 143 uid_t root_uid; 144 gid_t root_gid; 145 mode_t root_mode; 146 147 struct vattr va; 148 149 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts)) 150 return (EINVAL); 151 152 if (mp->mnt_flag & MNT_UPDATE) { 153 /* XXX: There is no support yet to update file system 154 * settings. Should be added. */ 155 156 return EOPNOTSUPP; 157 } 158 159 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY); 160 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred); 161 VOP_UNLOCK(mp->mnt_vnodecovered, 0); 162 if (error) 163 return (error); 164 165 if (mp->mnt_cred->cr_ruid != 0 || 166 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1) 167 root_gid = va.va_gid; 168 if (mp->mnt_cred->cr_ruid != 0 || 169 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1) 170 root_uid = va.va_uid; 171 if (mp->mnt_cred->cr_ruid != 0 || 172 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1) 173 root_mode = va.va_mode; 174 if (vfs_scanopt(mp->mnt_optnew, "inodes", "%u", &nodes_max) != 1) 175 nodes_max = 0; 176 if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1) 177 size_max = 0; 178 if (vfs_scanopt(mp->mnt_optnew, "maxfilesize", "%qu", 179 &maxfilesize) != 1) 180 maxfilesize = 0; 181 182 /* Do not allow mounts if we do not have enough memory to preserve 183 * the minimum reserved pages. */ 184 if (tmpfs_mem_info() < TMPFS_PAGES_RESERVED) 185 return ENOSPC; 186 187 /* Get the maximum number of memory pages this file system is 188 * allowed to use, based on the maximum size the user passed in 189 * the mount structure. A value of zero is treated as if the 190 * maximum available space was requested. */ 191 if (size_max < PAGE_SIZE || size_max > SIZE_MAX - PAGE_SIZE) 192 pages = SIZE_MAX; 193 else 194 pages = howmany(size_max, PAGE_SIZE); 195 MPASS(pages > 0); 196 197 if (nodes_max <= 3) { 198 if (pages > UINT32_MAX - 3) 199 nodes = UINT32_MAX; 200 else 201 nodes = pages + 3; 202 } else 203 nodes = nodes_max; 204 MPASS(nodes >= 3); 205 206 /* Allocate the tmpfs mount structure and fill it. */ 207 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount), 208 M_TMPFSMNT, M_WAITOK | M_ZERO); 209 210 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF); 211 tmp->tm_nodes_max = nodes; 212 tmp->tm_nodes_inuse = 0; 213 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : UINT64_MAX; 214 LIST_INIT(&tmp->tm_nodes_used); 215 216 tmp->tm_pages_max = pages; 217 tmp->tm_pages_used = 0; 218 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock); 219 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent", 220 sizeof(struct tmpfs_dirent), 221 NULL, NULL, NULL, NULL, 222 UMA_ALIGN_PTR, 0); 223 tmp->tm_node_pool = uma_zcreate("TMPFS node", 224 sizeof(struct tmpfs_node), 225 tmpfs_node_ctor, tmpfs_node_dtor, 226 tmpfs_node_init, tmpfs_node_fini, 227 UMA_ALIGN_PTR, 0); 228 229 /* Allocate the root node. */ 230 error = tmpfs_alloc_node(tmp, VDIR, root_uid, 231 root_gid, root_mode & ALLPERMS, NULL, NULL, 232 VNOVAL, &root); 233 234 if (error != 0 || root == NULL) { 235 uma_zdestroy(tmp->tm_node_pool); 236 uma_zdestroy(tmp->tm_dirent_pool); 237 delete_unrhdr(tmp->tm_ino_unr); 238 free(tmp, M_TMPFSMNT); 239 return error; 240 } 241 KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id)); 242 tmp->tm_root = root; 243 244 MNT_ILOCK(mp); 245 mp->mnt_flag |= MNT_LOCAL; 246 mp->mnt_kern_flag |= MNTK_MPSAFE; 247 MNT_IUNLOCK(mp); 248 249 mp->mnt_data = tmp; 250 mp->mnt_stat.f_namemax = MAXNAMLEN; 251 vfs_getnewfsid(mp); 252 vfs_mountedfrom(mp, "tmpfs"); 253 254 return 0; 255 } 256 257 /* --------------------------------------------------------------------- */ 258 259 /* ARGSUSED2 */ 260 static int 261 tmpfs_unmount(struct mount *mp, int mntflags) 262 { 263 int error; 264 int flags = 0; 265 struct tmpfs_mount *tmp; 266 struct tmpfs_node *node; 267 268 /* Handle forced unmounts. */ 269 if (mntflags & MNT_FORCE) 270 flags |= FORCECLOSE; 271 272 /* Finalize all pending I/O. */ 273 error = vflush(mp, 0, flags, curthread); 274 if (error != 0) 275 return error; 276 277 tmp = VFS_TO_TMPFS(mp); 278 279 /* Free all associated data. The loop iterates over the linked list 280 * we have containing all used nodes. For each of them that is 281 * a directory, we free all its directory entries. Note that after 282 * freeing a node, it will automatically go to the available list, 283 * so we will later have to iterate over it to release its items. */ 284 node = LIST_FIRST(&tmp->tm_nodes_used); 285 while (node != NULL) { 286 struct tmpfs_node *next; 287 288 if (node->tn_type == VDIR) { 289 struct tmpfs_dirent *de; 290 291 de = TAILQ_FIRST(&node->tn_dir.tn_dirhead); 292 while (de != NULL) { 293 struct tmpfs_dirent *nde; 294 295 nde = TAILQ_NEXT(de, td_entries); 296 tmpfs_free_dirent(tmp, de, FALSE); 297 de = nde; 298 node->tn_size -= sizeof(struct tmpfs_dirent); 299 } 300 } 301 302 next = LIST_NEXT(node, tn_entries); 303 tmpfs_free_node(tmp, node); 304 node = next; 305 } 306 307 uma_zdestroy(tmp->tm_dirent_pool); 308 uma_zdestroy(tmp->tm_node_pool); 309 delete_unrhdr(tmp->tm_ino_unr); 310 311 mtx_destroy(&tmp->allnode_lock); 312 MPASS(tmp->tm_pages_used == 0); 313 MPASS(tmp->tm_nodes_inuse == 0); 314 315 /* Throw away the tmpfs_mount structure. */ 316 free(mp->mnt_data, M_TMPFSMNT); 317 mp->mnt_data = NULL; 318 319 MNT_ILOCK(mp); 320 mp->mnt_flag &= ~MNT_LOCAL; 321 MNT_IUNLOCK(mp); 322 return 0; 323 } 324 325 /* --------------------------------------------------------------------- */ 326 327 static int 328 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp) 329 { 330 int error; 331 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp); 332 333 if (!error) 334 (*vpp)->v_vflag |= VV_ROOT; 335 336 return error; 337 } 338 339 /* --------------------------------------------------------------------- */ 340 341 static int 342 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, 343 struct vnode **vpp) 344 { 345 boolean_t found; 346 struct tmpfs_fid *tfhp; 347 struct tmpfs_mount *tmp; 348 struct tmpfs_node *node; 349 350 tmp = VFS_TO_TMPFS(mp); 351 352 tfhp = (struct tmpfs_fid *)fhp; 353 if (tfhp->tf_len != sizeof(struct tmpfs_fid)) 354 return EINVAL; 355 356 if (tfhp->tf_id >= tmp->tm_nodes_max) 357 return EINVAL; 358 359 found = FALSE; 360 361 TMPFS_LOCK(tmp); 362 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 363 if (node->tn_id == tfhp->tf_id && 364 node->tn_gen == tfhp->tf_gen) { 365 found = TRUE; 366 break; 367 } 368 } 369 TMPFS_UNLOCK(tmp); 370 371 if (found) 372 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp)); 373 374 return (EINVAL); 375 } 376 377 /* --------------------------------------------------------------------- */ 378 379 /* ARGSUSED2 */ 380 static int 381 tmpfs_statfs(struct mount *mp, struct statfs *sbp) 382 { 383 fsfilcnt_t freenodes; 384 struct tmpfs_mount *tmp; 385 386 tmp = VFS_TO_TMPFS(mp); 387 388 sbp->f_iosize = PAGE_SIZE; 389 sbp->f_bsize = PAGE_SIZE; 390 391 sbp->f_blocks = TMPFS_PAGES_MAX(tmp); 392 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp); 393 394 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse, 395 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node)); 396 397 sbp->f_files = freenodes + tmp->tm_nodes_inuse; 398 sbp->f_ffree = freenodes; 399 /* sbp->f_owner = tmp->tn_uid; */ 400 401 return 0; 402 } 403 404 /* --------------------------------------------------------------------- */ 405 406 /* 407 * tmpfs vfs operations. 408 */ 409 410 struct vfsops tmpfs_vfsops = { 411 .vfs_mount = tmpfs_mount, 412 .vfs_unmount = tmpfs_unmount, 413 .vfs_root = tmpfs_root, 414 .vfs_statfs = tmpfs_statfs, 415 .vfs_fhtovp = tmpfs_fhtovp, 416 }; 417 VFS_SET(tmpfs_vfsops, tmpfs, 0); 418