1 /* $NetBSD: tmpfs.h,v 1.55 2018/04/19 21:50:09 christos 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 /* Sequence number, see tmpfs_dir_getseq(). */ 58 uint32_t td_seq; 59 60 /* Name and its length. */ 61 char * td_name; 62 uint16_t td_namelen; 63 } tmpfs_dirent_t; 64 65 TAILQ_HEAD(tmpfs_dir, tmpfs_dirent); 66 67 /* 68 * Internal representation of a tmpfs file system node -- inode. 69 * 70 * This structure is split in two parts: one holds attributes common 71 * to all file types and the other holds data that is only applicable to 72 * a particular type. 73 * 74 * All fields are protected by vnode lock. The vnode association itself 75 * is protected by vcache. 76 */ 77 typedef struct tmpfs_node { 78 LIST_ENTRY(tmpfs_node) tn_entries; 79 80 /* 81 * Each inode has a corresponding vnode. It is a bi-directional 82 * association. Whenever vnode is allocated, its v_data field is 83 * set to the inode it reference, and tmpfs_node_t::tn_vnode is 84 * set to point to the said vnode. 85 * 86 * Further attempts to allocate a vnode for this same node will 87 * result in returning a new reference to the value stored in 88 * tn_vnode. It may be NULL when the node is unused (that is, 89 * no vnode has been allocated or it has been reclaimed). 90 */ 91 vnode_t * tn_vnode; 92 93 /* Prevent node from being reclaimed. */ 94 uint32_t tn_holdcount; 95 96 /* Directory entry. Only a hint, since hard link can have multiple. */ 97 tmpfs_dirent_t * tn_dirent_hint; 98 99 /* The inode type: VBLK, VCHR, VDIR, VFIFO, VLNK, VREG or VSOCK. */ 100 enum vtype tn_type; 101 102 /* Inode identifier and generation number. */ 103 ino_t tn_id; 104 uint32_t tn_gen; 105 106 /* The inode size. */ 107 off_t tn_size; 108 109 /* Generic node attributes. */ 110 uid_t tn_uid; 111 gid_t tn_gid; 112 mode_t tn_mode; 113 int tn_flags; 114 nlink_t tn_links; 115 struct timespec tn_atime; 116 struct timespec tn_mtime; 117 struct timespec tn_ctime; 118 struct timespec tn_birthtime; 119 120 /* Head of byte-level lock list (used by tmpfs_advlock). */ 121 struct lockf * tn_lockf; 122 123 union { 124 /* Type case: VBLK or VCHR. */ 125 struct { 126 dev_t tn_rdev; 127 } tn_dev; 128 129 /* Type case: VDIR. */ 130 struct { 131 /* Parent directory (root inode points to itself). */ 132 struct tmpfs_node * tn_parent; 133 134 /* List of directory entries. */ 135 struct tmpfs_dir tn_dir; 136 137 /* Last given sequence number and their arena. */ 138 uint32_t tn_next_seq; 139 void * tn_seq_arena; 140 141 /* 142 * Pointer of the last directory entry returned 143 * by the readdir(3) operation. 144 */ 145 struct tmpfs_dirent * tn_readdir_lastp; 146 } tn_dir; 147 148 /* Type case: VLNK. */ 149 struct tn_lnk { 150 /* The link's target. */ 151 char * tn_link; 152 } tn_lnk; 153 154 /* Type case: VREG. */ 155 struct tn_reg { 156 /* Underlying UVM object to store contents. */ 157 struct uvm_object * tn_aobj; 158 size_t tn_aobj_pages; 159 } tn_reg; 160 } tn_spec; 161 } tmpfs_node_t; 162 163 #if defined(_KERNEL) 164 165 VFS_PROTOS(tmpfs); 166 167 LIST_HEAD(tmpfs_node_list, tmpfs_node); 168 169 #define TMPFS_MAXNAMLEN 255 170 /* Validate maximum td_namelen length. */ 171 CTASSERT(TMPFS_MAXNAMLEN < UINT16_MAX); 172 173 /* 174 * Reserved values for the virtual entries (the first must be 0) and EOF. 175 * The start/end of the incremental range, see tmpfs_dir_getseq(). 176 */ 177 #define TMPFS_DIRSEQ_DOT 0 178 #define TMPFS_DIRSEQ_DOTDOT 1 179 #define TMPFS_DIRSEQ_EOF 2 180 181 #define TMPFS_DIRSEQ_START 3 /* inclusive */ 182 #define TMPFS_DIRSEQ_END (1U << 30) /* exclusive */ 183 184 /* Mark to indicate that the number is not set. */ 185 #define TMPFS_DIRSEQ_NONE (1U << 31) 186 187 /* Flags: time update requests. */ 188 #define TMPFS_UPDATE_ATIME 0x01 189 #define TMPFS_UPDATE_MTIME 0x02 190 #define TMPFS_UPDATE_CTIME 0x04 191 192 /* 193 * Bits indicating whiteout use for the directory. 194 * We abuse tmpfs_node_t::tn_gen for that. 195 */ 196 #define TMPFS_WHITEOUT_BIT (1U << 31) 197 #define TMPFS_NODE_GEN_MASK (TMPFS_WHITEOUT_BIT - 1) 198 199 #define TMPFS_NODE_GEN(node) \ 200 ((node)->tn_gen & TMPFS_NODE_GEN_MASK) 201 202 /* White-out inode indicator. */ 203 #define TMPFS_NODE_WHITEOUT ((tmpfs_node_t *)-1) 204 205 /* 206 * Bit indicating this node must be reclaimed when holdcount reaches zero. 207 * Ored into tmpfs_node_t::tn_holdcount. 208 */ 209 #define TMPFS_NODE_RECLAIMED (1U << 30) 210 211 /* 212 * Internal representation of a tmpfs mount point. 213 */ 214 typedef struct tmpfs_mount { 215 /* Limit and number of bytes in use by the file system. */ 216 uint64_t tm_mem_limit; 217 uint64_t tm_bytes_used; 218 kmutex_t tm_acc_lock; 219 220 /* Pointer to the root inode. */ 221 tmpfs_node_t * tm_root; 222 223 /* Maximum number of possible nodes for this file system. */ 224 unsigned int tm_nodes_max; 225 226 /* Number of nodes currently allocated. */ 227 unsigned int tm_nodes_cnt; 228 229 /* List of inodes and the lock protecting it. */ 230 kmutex_t tm_lock; 231 struct tmpfs_node_list tm_nodes; 232 } tmpfs_mount_t; 233 234 /* 235 * This structure maps a file identifier to a tmpfs node. Used by the 236 * NFS code. 237 */ 238 typedef struct tmpfs_fid { 239 uint16_t tf_len; 240 uint16_t tf_pad; 241 uint32_t tf_gen; 242 ino_t tf_id; 243 } tmpfs_fid_t; 244 245 /* 246 * Prototypes for tmpfs_subr.c. 247 */ 248 249 void tmpfs_free_node(tmpfs_mount_t *, tmpfs_node_t *); 250 251 int tmpfs_construct_node(vnode_t *, vnode_t **, struct vattr *, 252 struct componentname *, char *); 253 254 int tmpfs_alloc_dirent(tmpfs_mount_t *, const char *, uint16_t, 255 tmpfs_dirent_t **); 256 void tmpfs_free_dirent(tmpfs_mount_t *, tmpfs_dirent_t *); 257 void tmpfs_dir_attach(tmpfs_node_t *, tmpfs_dirent_t *, tmpfs_node_t *); 258 void tmpfs_dir_detach(tmpfs_node_t *, tmpfs_dirent_t *); 259 260 tmpfs_dirent_t *tmpfs_dir_lookup(tmpfs_node_t *, struct componentname *); 261 tmpfs_dirent_t *tmpfs_dir_cached(tmpfs_node_t *); 262 263 uint32_t tmpfs_dir_getseq(tmpfs_node_t *, tmpfs_dirent_t *); 264 tmpfs_dirent_t *tmpfs_dir_lookupbyseq(tmpfs_node_t *, off_t); 265 int tmpfs_dir_getdents(tmpfs_node_t *, struct uio *, off_t *); 266 267 int tmpfs_reg_resize(vnode_t *, off_t); 268 269 int tmpfs_chflags(vnode_t *, int, kauth_cred_t, lwp_t *); 270 int tmpfs_chmod(vnode_t *, mode_t, kauth_cred_t, lwp_t *); 271 int tmpfs_chown(vnode_t *, uid_t, gid_t, kauth_cred_t, lwp_t *); 272 int tmpfs_chsize(vnode_t *, u_quad_t, kauth_cred_t, lwp_t *); 273 int tmpfs_chtimes(vnode_t *, const struct timespec *, 274 const struct timespec *, const struct timespec *, int, 275 kauth_cred_t, lwp_t *); 276 void tmpfs_update(vnode_t *, unsigned); 277 278 /* 279 * Prototypes for tmpfs_mem.c. 280 */ 281 282 void tmpfs_mntmem_init(tmpfs_mount_t *, uint64_t); 283 void tmpfs_mntmem_destroy(tmpfs_mount_t *); 284 int tmpfs_mntmem_set(tmpfs_mount_t *, uint64_t); 285 286 size_t tmpfs_mem_info(bool); 287 uint64_t tmpfs_bytes_max(tmpfs_mount_t *); 288 size_t tmpfs_pages_avail(tmpfs_mount_t *); 289 bool tmpfs_mem_incr(tmpfs_mount_t *, size_t); 290 void tmpfs_mem_decr(tmpfs_mount_t *, size_t); 291 292 tmpfs_dirent_t *tmpfs_dirent_get(tmpfs_mount_t *); 293 void tmpfs_dirent_put(tmpfs_mount_t *, tmpfs_dirent_t *); 294 295 tmpfs_node_t * tmpfs_node_get(tmpfs_mount_t *); 296 void tmpfs_node_put(tmpfs_mount_t *, tmpfs_node_t *); 297 298 char * tmpfs_strname_alloc(tmpfs_mount_t *, size_t); 299 void tmpfs_strname_free(tmpfs_mount_t *, char *, size_t); 300 bool tmpfs_strname_neqlen(struct componentname *, struct componentname *); 301 302 /* 303 * Ensures that the node pointed by 'node' is a directory and that its 304 * contents are consistent with respect to directories. 305 */ 306 #define TMPFS_VALIDATE_DIR(node) \ 307 KASSERT((node)->tn_vnode == NULL || VOP_ISLOCKED((node)->tn_vnode)); \ 308 KASSERT((node)->tn_type == VDIR); \ 309 KASSERT((node)->tn_size % sizeof(tmpfs_dirent_t) == 0); 310 311 /* 312 * Routines to convert VFS structures to tmpfs internal ones. 313 */ 314 315 static __inline tmpfs_mount_t * 316 VFS_TO_TMPFS(struct mount *mp) 317 { 318 tmpfs_mount_t *tmp = mp->mnt_data; 319 320 KASSERT(tmp != NULL); 321 return tmp; 322 } 323 324 static __inline tmpfs_node_t * 325 VP_TO_TMPFS_DIR(vnode_t *vp) 326 { 327 tmpfs_node_t *node = vp->v_data; 328 329 KASSERT(node != NULL); 330 TMPFS_VALIDATE_DIR(node); 331 return node; 332 } 333 334 #endif /* defined(_KERNEL) */ 335 336 static __inline tmpfs_node_t * 337 VP_TO_TMPFS_NODE(vnode_t *vp) 338 { 339 tmpfs_node_t *node = vp->v_data; 340 #ifdef KASSERT 341 KASSERT(node != NULL); 342 #endif 343 return node; 344 } 345 346 #endif /* _FS_TMPFS_TMPFS_H_ */ 347