1 /* $NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $ */
4 * Copyright (c) 2005 The NetBSD Foundation, Inc.
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
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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.
34 * Efficient memory file system.
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.
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
46 #include <sys/param.h>
47 #include <sys/limits.h>
49 #include <sys/mutex.h>
50 #include <sys/kernel.h>
52 #include <sys/systm.h>
53 #include <sys/sysctl.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_param.h>
59 #include <fs/tmpfs/tmpfs.h>
62 * Default permission for root node
64 #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
66 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
67 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
69 /* --------------------------------------------------------------------- */
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,
76 static int tmpfs_statfs(struct mount *, struct statfs *);
78 /* --------------------------------------------------------------------- */
80 static const char *tmpfs_opts[] = {
81 "from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export",
85 /* --------------------------------------------------------------------- */
88 tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
90 struct tmpfs_node *node = (struct tmpfs_node *)mem;
97 node->tn_vnode = NULL;
104 tmpfs_node_dtor(void *mem, int size, void *arg)
106 struct tmpfs_node *node = (struct tmpfs_node *)mem;
107 node->tn_type = VNON;
111 tmpfs_node_init(void *mem, int size, int flags)
113 struct tmpfs_node *node = (struct tmpfs_node *)mem;
116 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
117 node->tn_gen = arc4random();
123 tmpfs_node_fini(void *mem, int size)
125 struct tmpfs_node *node = (struct tmpfs_node *)mem;
127 mtx_destroy(&node->tn_interlock);
131 tmpfs_mount(struct mount *mp)
133 struct tmpfs_mount *tmp;
134 struct tmpfs_node *root;
140 u_quad_t size_max, maxfilesize;
142 /* Root node attributes. */
149 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
152 if (mp->mnt_flag & MNT_UPDATE) {
153 /* XXX: There is no support yet to update file system
154 * settings. Should be added. */
159 printf("WARNING: TMPFS is considered to be a highly experimental "
160 "feature in FreeBSD.\n");
162 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
163 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
164 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
168 if (mp->mnt_cred->cr_ruid != 0 ||
169 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
170 root_gid = va.va_gid;
171 if (mp->mnt_cred->cr_ruid != 0 ||
172 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
173 root_uid = va.va_uid;
174 if (mp->mnt_cred->cr_ruid != 0 ||
175 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
176 root_mode = va.va_mode;
177 if (vfs_scanopt(mp->mnt_optnew, "inodes", "%u", &nodes_max) != 1)
179 if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1)
181 if (vfs_scanopt(mp->mnt_optnew, "maxfilesize", "%qu",
185 /* Do not allow mounts if we do not have enough memory to preserve
186 * the minimum reserved pages. */
187 if (tmpfs_mem_info() < TMPFS_PAGES_RESERVED)
190 /* Get the maximum number of memory pages this file system is
191 * allowed to use, based on the maximum size the user passed in
192 * the mount structure. A value of zero is treated as if the
193 * maximum available space was requested. */
194 if (size_max < PAGE_SIZE || size_max > SIZE_MAX - PAGE_SIZE)
197 pages = howmany(size_max, PAGE_SIZE);
200 if (nodes_max <= 3) {
201 if (pages > UINT32_MAX - 3)
209 /* Allocate the tmpfs mount structure and fill it. */
210 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
211 M_TMPFSMNT, M_WAITOK | M_ZERO);
213 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
214 tmp->tm_nodes_max = nodes;
215 tmp->tm_nodes_inuse = 0;
216 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : UINT64_MAX;
217 LIST_INIT(&tmp->tm_nodes_used);
219 tmp->tm_pages_max = pages;
220 tmp->tm_pages_used = 0;
221 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
222 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
223 sizeof(struct tmpfs_dirent),
224 NULL, NULL, NULL, NULL,
226 tmp->tm_node_pool = uma_zcreate("TMPFS node",
227 sizeof(struct tmpfs_node),
228 tmpfs_node_ctor, tmpfs_node_dtor,
229 tmpfs_node_init, tmpfs_node_fini,
232 /* Allocate the root node. */
233 error = tmpfs_alloc_node(tmp, VDIR, root_uid,
234 root_gid, root_mode & ALLPERMS, NULL, NULL,
237 if (error != 0 || root == NULL) {
238 uma_zdestroy(tmp->tm_node_pool);
239 uma_zdestroy(tmp->tm_dirent_pool);
240 delete_unrhdr(tmp->tm_ino_unr);
241 free(tmp, M_TMPFSMNT);
244 KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
248 mp->mnt_flag |= MNT_LOCAL;
249 mp->mnt_kern_flag |= MNTK_MPSAFE;
253 mp->mnt_stat.f_namemax = MAXNAMLEN;
255 vfs_mountedfrom(mp, "tmpfs");
260 /* --------------------------------------------------------------------- */
264 tmpfs_unmount(struct mount *mp, int mntflags)
268 struct tmpfs_mount *tmp;
269 struct tmpfs_node *node;
271 /* Handle forced unmounts. */
272 if (mntflags & MNT_FORCE)
275 /* Finalize all pending I/O. */
276 error = vflush(mp, 0, flags, curthread);
280 tmp = VFS_TO_TMPFS(mp);
282 /* Free all associated data. The loop iterates over the linked list
283 * we have containing all used nodes. For each of them that is
284 * a directory, we free all its directory entries. Note that after
285 * freeing a node, it will automatically go to the available list,
286 * so we will later have to iterate over it to release its items. */
287 node = LIST_FIRST(&tmp->tm_nodes_used);
288 while (node != NULL) {
289 struct tmpfs_node *next;
291 if (node->tn_type == VDIR) {
292 struct tmpfs_dirent *de;
294 de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
296 struct tmpfs_dirent *nde;
298 nde = TAILQ_NEXT(de, td_entries);
299 tmpfs_free_dirent(tmp, de, FALSE);
301 node->tn_size -= sizeof(struct tmpfs_dirent);
305 next = LIST_NEXT(node, tn_entries);
306 tmpfs_free_node(tmp, node);
310 uma_zdestroy(tmp->tm_dirent_pool);
311 uma_zdestroy(tmp->tm_node_pool);
312 delete_unrhdr(tmp->tm_ino_unr);
314 mtx_destroy(&tmp->allnode_lock);
315 MPASS(tmp->tm_pages_used == 0);
316 MPASS(tmp->tm_nodes_inuse == 0);
318 /* Throw away the tmpfs_mount structure. */
319 free(mp->mnt_data, M_TMPFSMNT);
323 mp->mnt_flag &= ~MNT_LOCAL;
328 /* --------------------------------------------------------------------- */
331 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
334 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
337 (*vpp)->v_vflag |= VV_ROOT;
342 /* --------------------------------------------------------------------- */
345 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
349 struct tmpfs_fid *tfhp;
350 struct tmpfs_mount *tmp;
351 struct tmpfs_node *node;
353 tmp = VFS_TO_TMPFS(mp);
355 tfhp = (struct tmpfs_fid *)fhp;
356 if (tfhp->tf_len != sizeof(struct tmpfs_fid))
359 if (tfhp->tf_id >= tmp->tm_nodes_max)
365 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
366 if (node->tn_id == tfhp->tf_id &&
367 node->tn_gen == tfhp->tf_gen) {
375 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp));
380 /* --------------------------------------------------------------------- */
384 tmpfs_statfs(struct mount *mp, struct statfs *sbp)
386 fsfilcnt_t freenodes;
387 struct tmpfs_mount *tmp;
389 tmp = VFS_TO_TMPFS(mp);
391 sbp->f_iosize = PAGE_SIZE;
392 sbp->f_bsize = PAGE_SIZE;
394 sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
395 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
397 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
398 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
400 sbp->f_files = freenodes + tmp->tm_nodes_inuse;
401 sbp->f_ffree = freenodes;
402 /* sbp->f_owner = tmp->tn_uid; */
407 /* --------------------------------------------------------------------- */
410 * tmpfs vfs operations.
413 struct vfsops tmpfs_vfsops = {
414 .vfs_mount = tmpfs_mount,
415 .vfs_unmount = tmpfs_unmount,
416 .vfs_root = tmpfs_root,
417 .vfs_statfs = tmpfs_statfs,
418 .vfs_fhtovp = tmpfs_fhtovp,
420 VFS_SET(tmpfs_vfsops, tmpfs, 0);