1 /* $NetBSD: tmpfs.h,v 1.44 2011/05/29 22:29:06 rmind Exp $ */ 2 3 /* 4 * Copyright (c) 2005, 2006, 2007 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 #ifndef _FS_TMPFS_TMPFS_H_ 34 #define _FS_TMPFS_TMPFS_H_ 35 36 #if !defined(_KERNEL) && !defined(_KMEMUSER) 37 #error "not supposed to be exposed to userland" 38 #endif 39 40 #include <sys/dirent.h> 41 #include <sys/mount.h> 42 #include <sys/pool.h> 43 #include <sys/queue.h> 44 #include <sys/vnode.h> 45 46 /* 47 * Internal representation of a tmpfs directory entry. 48 * 49 * All fields are protected by vnode lock. 50 */ 51 typedef struct tmpfs_dirent { 52 TAILQ_ENTRY(tmpfs_dirent) td_entries; 53 54 /* Pointer to the inode this entry refers to. */ 55 struct tmpfs_node * td_node; 56 57 /* Name and its length. */ 58 char * td_name; 59 uint16_t td_namelen; 60 } tmpfs_dirent_t; 61 62 TAILQ_HEAD(tmpfs_dir, tmpfs_dirent); 63 64 #if defined(_KERNEL) 65 66 /* Validate maximum td_namelen length. */ 67 CTASSERT(MAXNAMLEN < UINT16_MAX); 68 69 #define TMPFS_DIRCOOKIE_DOT 0 70 #define TMPFS_DIRCOOKIE_DOTDOT 1 71 #define TMPFS_DIRCOOKIE_EOF 2 72 73 /* 74 * Each entry in a directory has a cookie that identifies it. Cookies 75 * supersede offsets within directories, as tmpfs has no offsets as such. 76 * 77 * The '.', '..' and the end of directory markers have fixed cookies, 78 * which cannot collide with the cookies generated by other entries. 79 * 80 * The cookies for the other entries are generated based on the memory 81 * address of their representative meta-data structure. 82 * 83 * XXX: Truncating directory cookies to 31 bits now - workaround for 84 * problem with Linux compat, see PR/32034. 85 */ 86 static inline off_t 87 tmpfs_dircookie(tmpfs_dirent_t *de) 88 { 89 off_t cookie; 90 91 cookie = ((off_t)(uintptr_t)de >> 1) & 0x7FFFFFFF; 92 KASSERT(cookie != TMPFS_DIRCOOKIE_DOT); 93 KASSERT(cookie != TMPFS_DIRCOOKIE_DOTDOT); 94 KASSERT(cookie != TMPFS_DIRCOOKIE_EOF); 95 96 return cookie; 97 } 98 #endif 99 100 /* 101 * Internal representation of a tmpfs file system node -- inode. 102 * 103 * This structure is splitted in two parts: one holds attributes common 104 * to all file types and the other holds data that is only applicable to 105 * a particular type. 106 * 107 * All fields are protected by vnode lock. The vnode association itself 108 * is protected by tmpfs_node_t::tn_vlock. 109 */ 110 typedef struct tmpfs_node { 111 LIST_ENTRY(tmpfs_node) tn_entries; 112 113 /* 114 * Each inode has a corresponding vnode. It is a bi-directional 115 * association. Whenever vnode is allocated, its v_data field is 116 * set to the inode it reference, and tmpfs_node_t::tn_vnode is 117 * set to point to the said vnode. 118 * 119 * Further attempts to allocate a vnode for this same node will 120 * result in returning a new reference to the value stored in 121 * tn_vnode. It may be NULL when the node is unused (that is, 122 * no vnode has been allocated or it has been reclaimed). 123 */ 124 kmutex_t tn_vlock; 125 vnode_t * tn_vnode; 126 127 /* Directory entry. Only a hint, since hard link can have multiple. */ 128 tmpfs_dirent_t * tn_dirent_hint; 129 130 /* The inode type: VBLK, VCHR, VDIR, VFIFO, VLNK, VREG or VSOCK. */ 131 enum vtype tn_type; 132 133 /* Inode identifier and generation number. */ 134 ino_t tn_id; 135 unsigned long tn_gen; 136 137 /* Inode status flags (for operations in delayed manner). */ 138 int tn_status; 139 140 /* The inode size. */ 141 off_t tn_size; 142 143 /* Generic node attributes. */ 144 uid_t tn_uid; 145 gid_t tn_gid; 146 mode_t tn_mode; 147 int tn_flags; 148 nlink_t tn_links; 149 struct timespec tn_atime; 150 struct timespec tn_mtime; 151 struct timespec tn_ctime; 152 struct timespec tn_birthtime; 153 154 /* Head of byte-level lock list (used by tmpfs_advlock). */ 155 struct lockf * tn_lockf; 156 157 union { 158 /* Type case: VBLK or VCHR. */ 159 struct { 160 dev_t tn_rdev; 161 } tn_dev; 162 163 /* Type case: VDIR. */ 164 struct { 165 /* Parent directory (root inode points to itself). */ 166 struct tmpfs_node * tn_parent; 167 168 /* List of directory entries. */ 169 struct tmpfs_dir tn_dir; 170 171 /* 172 * Number and pointer of the last directory entry 173 * returned by the readdir(3) operation. 174 */ 175 off_t tn_readdir_lastn; 176 struct tmpfs_dirent * tn_readdir_lastp; 177 } tn_dir; 178 179 /* Type case: VLNK. */ 180 struct tn_lnk { 181 /* The link's target. */ 182 char * tn_link; 183 } tn_lnk; 184 185 /* Type case: VREG. */ 186 struct tn_reg { 187 /* Underlying UVM object to store contents. */ 188 struct uvm_object * tn_aobj; 189 size_t tn_aobj_pages; 190 } tn_reg; 191 } tn_spec; 192 } tmpfs_node_t; 193 194 #if defined(_KERNEL) 195 196 LIST_HEAD(tmpfs_node_list, tmpfs_node); 197 198 /* Status flags. */ 199 #define TMPFS_NODE_ACCESSED 0x01 200 #define TMPFS_NODE_MODIFIED 0x02 201 #define TMPFS_NODE_CHANGED 0x04 202 203 #define TMPFS_NODE_STATUSALL \ 204 (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED) 205 206 /* 207 * Bit indicating vnode reclamation. 208 * We abuse tmpfs_node_t::tn_gen for that. 209 */ 210 #define TMPFS_NODE_GEN_MASK (~0UL >> 1) 211 #define TMPFS_RECLAIMING_BIT (~TMPFS_NODE_GEN_MASK) 212 213 #define TMPFS_NODE_RECLAIMING(node) \ 214 (((node)->tn_gen & TMPFS_RECLAIMING_BIT) != 0) 215 216 #define TMPFS_NODE_GEN(node) \ 217 ((node)->tn_gen & TMPFS_NODE_GEN_MASK) 218 219 /* White-out inode indicator. */ 220 #define TMPFS_NODE_WHITEOUT ((tmpfs_node_t *)-1) 221 222 /* 223 * Internal representation of a tmpfs mount point. 224 */ 225 typedef struct tmpfs_mount { 226 /* Limit and number of bytes in use by the file system. */ 227 uint64_t tm_mem_limit; 228 uint64_t tm_bytes_used; 229 kmutex_t tm_acc_lock; 230 231 /* Pointer to the root inode. */ 232 tmpfs_node_t * tm_root; 233 234 /* Maximum number of possible nodes for this file system. */ 235 unsigned int tm_nodes_max; 236 237 /* Number of nodes currently allocated. */ 238 unsigned int tm_nodes_cnt; 239 240 /* List of inodes and the lock protecting it. */ 241 kmutex_t tm_lock; 242 struct tmpfs_node_list tm_nodes; 243 } tmpfs_mount_t; 244 245 /* 246 * This structure maps a file identifier to a tmpfs node. Used by the 247 * NFS code. 248 */ 249 typedef struct tmpfs_fid { 250 uint16_t tf_len; 251 uint16_t tf_pad; 252 uint32_t tf_gen; 253 ino_t tf_id; 254 } tmpfs_fid_t; 255 256 /* 257 * Prototypes for tmpfs_subr.c. 258 */ 259 260 int tmpfs_alloc_node(tmpfs_mount_t *, enum vtype, uid_t, gid_t, 261 mode_t, char *, dev_t, tmpfs_node_t **); 262 void tmpfs_free_node(tmpfs_mount_t *, tmpfs_node_t *); 263 264 int tmpfs_alloc_file(vnode_t *, vnode_t **, struct vattr *, 265 struct componentname *, char *); 266 267 int tmpfs_vnode_get(struct mount *, tmpfs_node_t *, vnode_t **); 268 269 int tmpfs_alloc_dirent(tmpfs_mount_t *, const char *, uint16_t, 270 tmpfs_dirent_t **); 271 void tmpfs_free_dirent(tmpfs_mount_t *, tmpfs_dirent_t *); 272 void tmpfs_dir_attach(vnode_t *, tmpfs_dirent_t *, tmpfs_node_t *); 273 void tmpfs_dir_detach(vnode_t *, tmpfs_dirent_t *); 274 275 tmpfs_dirent_t *tmpfs_dir_lookup(tmpfs_node_t *, struct componentname *); 276 tmpfs_dirent_t *tmpfs_dir_cached(tmpfs_node_t *); 277 278 int tmpfs_dir_getdotdent(tmpfs_node_t *, struct uio *); 279 int tmpfs_dir_getdotdotdent(tmpfs_node_t *, struct uio *); 280 tmpfs_dirent_t *tmpfs_dir_lookupbycookie(tmpfs_node_t *, off_t); 281 int tmpfs_dir_getdents(tmpfs_node_t *, struct uio *, off_t *); 282 283 int tmpfs_reg_resize(vnode_t *, off_t); 284 int tmpfs_truncate(vnode_t *, off_t); 285 286 int tmpfs_chflags(vnode_t *, int, kauth_cred_t, lwp_t *); 287 int tmpfs_chmod(vnode_t *, mode_t, kauth_cred_t, lwp_t *); 288 int tmpfs_chown(vnode_t *, uid_t, gid_t, kauth_cred_t, lwp_t *); 289 int tmpfs_chsize(vnode_t *, u_quad_t, kauth_cred_t, lwp_t *); 290 int tmpfs_chtimes(vnode_t *, const struct timespec *, 291 const struct timespec *, const struct timespec *, int, 292 kauth_cred_t, lwp_t *); 293 void tmpfs_update(vnode_t *, const struct timespec *, 294 const struct timespec *, const struct timespec *, int); 295 296 /* 297 * Prototypes for tmpfs_mem.c. 298 */ 299 300 void tmpfs_mntmem_init(tmpfs_mount_t *, uint64_t); 301 void tmpfs_mntmem_destroy(tmpfs_mount_t *); 302 303 size_t tmpfs_mem_info(bool); 304 uint64_t tmpfs_bytes_max(tmpfs_mount_t *); 305 size_t tmpfs_pages_avail(tmpfs_mount_t *); 306 bool tmpfs_mem_incr(tmpfs_mount_t *, size_t); 307 void tmpfs_mem_decr(tmpfs_mount_t *, size_t); 308 309 tmpfs_dirent_t *tmpfs_dirent_get(tmpfs_mount_t *); 310 void tmpfs_dirent_put(tmpfs_mount_t *, tmpfs_dirent_t *); 311 312 tmpfs_node_t * tmpfs_node_get(tmpfs_mount_t *); 313 void tmpfs_node_put(tmpfs_mount_t *, tmpfs_node_t *); 314 315 char * tmpfs_strname_alloc(tmpfs_mount_t *, size_t); 316 void tmpfs_strname_free(tmpfs_mount_t *, char *, size_t); 317 bool tmpfs_strname_neqlen(struct componentname *, struct componentname *); 318 319 /* 320 * Ensures that the node pointed by 'node' is a directory and that its 321 * contents are consistent with respect to directories. 322 */ 323 #define TMPFS_VALIDATE_DIR(node) \ 324 KASSERT((node)->tn_type == VDIR); \ 325 KASSERT((node)->tn_size % sizeof(tmpfs_dirent_t) == 0); \ 326 KASSERT((node)->tn_spec.tn_dir.tn_readdir_lastp == NULL || \ 327 tmpfs_dircookie((node)->tn_spec.tn_dir.tn_readdir_lastp) == \ 328 (node)->tn_spec.tn_dir.tn_readdir_lastn); 329 330 /* 331 * Memory management stuff. 332 */ 333 334 /* Amount of memory pages to reserve for the system. */ 335 #define TMPFS_PAGES_RESERVED (4 * 1024 * 1024 / PAGE_SIZE) 336 337 /* 338 * Routines to convert VFS structures to tmpfs internal ones. 339 */ 340 341 static inline tmpfs_mount_t * 342 VFS_TO_TMPFS(struct mount *mp) 343 { 344 tmpfs_mount_t *tmp = mp->mnt_data; 345 346 KASSERT(tmp != NULL); 347 return tmp; 348 } 349 350 static inline tmpfs_node_t * 351 VP_TO_TMPFS_DIR(vnode_t *vp) 352 { 353 tmpfs_node_t *node = vp->v_data; 354 355 KASSERT(node != NULL); 356 TMPFS_VALIDATE_DIR(node); 357 return node; 358 } 359 360 #endif /* defined(_KERNEL) */ 361 362 static __inline tmpfs_node_t * 363 VP_TO_TMPFS_NODE(vnode_t *vp) 364 { 365 tmpfs_node_t *node = vp->v_data; 366 #ifdef KASSERT 367 KASSERT(node != NULL); 368 #endif 369 return node; 370 } 371 372 #endif /* _FS_TMPFS_TMPFS_H_ */ 373