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.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
41 * Efficient memory file system.
43 * tmpfs is a file system that uses NetBSD's virtual memory sub-system
44 * (the well-known UVM) to store file data and metadata in an efficient
45 * way. This means that it does not follow the structure of an on-disk
46 * file system because it simply does not need to. Instead, it uses
47 * memory-specific data structures and algorithms to automatically
48 * allocate and release resources.
50 #include <sys/cdefs.h>
51 __FBSDID("$FreeBSD$");
53 #include <sys/param.h>
54 #include <sys/limits.h>
56 #include <sys/mutex.h>
57 #include <sys/kernel.h>
59 #include <sys/systm.h>
60 #include <sys/sysctl.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_param.h>
66 #include <fs/tmpfs/tmpfs.h>
69 * Default permission for root node
71 #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
73 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
74 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
76 /* --------------------------------------------------------------------- */
78 static int tmpfs_mount(struct mount *, struct thread *);
79 static int tmpfs_unmount(struct mount *, int, struct thread *);
80 static int tmpfs_root(struct mount *, int flags, struct vnode **,
82 static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **);
83 static int tmpfs_statfs(struct mount *, struct statfs *, struct thread *);
85 /* --------------------------------------------------------------------- */
87 static const char *tmpfs_opts[] = {
88 "from", "size", "inodes", "uid", "gid", "mode", "export",
92 /* --------------------------------------------------------------------- */
100 char *sname = "vm.swap_info";
101 int soid[SWI_MAXMIB], oid[2];
102 u_int unswdev, total, dmmax, nswapdev;
108 if (kernel_sysctlbyname(curthread, "vm.dmmax", &dmmax, &len,
109 NULL, 0, NULL, 0) != 0)
112 len = sizeof(nswapdev);
113 if (kernel_sysctlbyname(curthread, "vm.nswapdev",
115 NULL, 0, NULL, 0) != 0)
118 mibi = (SWI_MAXMIB - 1) * sizeof(int);
122 if (kernel_sysctl(curthread, oid, 2,
123 soid, &mibi, (void *)sname, strlen(sname),
127 mibi = (SWI_MAXMIB - 1);
128 for (unswdev = 0; unswdev < nswapdev; ++unswdev) {
129 soid[mibi] = unswdev;
130 len = sizeof(struct xswdev);
131 if (kernel_sysctl(curthread,
132 soid, mibi + 1, &xsd, &len, NULL, 0,
135 if (len == sizeof(struct xswdev))
136 total += (xsd.xsw_nblks - dmmax);
143 /* --------------------------------------------------------------------- */
145 tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
147 struct tmpfs_node *node = (struct tmpfs_node *)mem;
154 node->tn_vnode = NULL;
155 node->tn_vpstate = 0;
161 tmpfs_node_dtor(void *mem, int size, void *arg)
163 struct tmpfs_node *node = (struct tmpfs_node *)mem;
164 node->tn_type = VNON;
168 tmpfs_node_init(void *mem, int size, int flags)
170 struct tmpfs_node *node = (struct tmpfs_node *)mem;
173 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
174 node->tn_gen = arc4random();
180 tmpfs_node_fini(void *mem, int size)
182 struct tmpfs_node *node = (struct tmpfs_node *)mem;
184 mtx_destroy(&node->tn_interlock);
188 tmpfs_mount(struct mount *mp, struct thread *td)
190 struct tmpfs_mount *tmp;
191 struct tmpfs_node *root;
192 size_t pages, mem_size;
199 /* Root node attributes. */
206 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
209 if (mp->mnt_flag & MNT_UPDATE) {
210 /* XXX: There is no support yet to update file system
211 * settings. Should be added. */
216 printf("WARNING: TMPFS is considered to be a highly experimental "
217 "feature in FreeBSD.\n");
219 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
220 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred, td);
221 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
225 if (mp->mnt_cred->cr_ruid != 0 ||
226 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
227 root_gid = va.va_gid;
228 if (mp->mnt_cred->cr_ruid != 0 ||
229 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
230 root_uid = va.va_uid;
231 if (mp->mnt_cred->cr_ruid != 0 ||
232 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
233 root_mode = va.va_mode;
234 if (vfs_scanopt(mp->mnt_optnew, "inodes", "%d", &nodes_max) != 1)
236 if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1)
239 /* Do not allow mounts if we do not have enough memory to preserve
240 * the minimum reserved pages. */
241 mem_size = cnt.v_free_count + cnt.v_inactive_count + get_swpgtotal();
242 mem_size -= mem_size > cnt.v_wire_count ? cnt.v_wire_count : mem_size;
243 if (mem_size < TMPFS_PAGES_RESERVED)
246 /* Get the maximum number of memory pages this file system is
247 * allowed to use, based on the maximum size the user passed in
248 * the mount structure. A value of zero is treated as if the
249 * maximum available space was requested. */
250 if (size_max < PAGE_SIZE || size_max >= SIZE_MAX)
253 pages = howmany(size_max, PAGE_SIZE);
257 nodes = 3 + pages * PAGE_SIZE / 1024;
262 /* Allocate the tmpfs mount structure and fill it. */
263 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
264 M_TMPFSMNT, M_WAITOK | M_ZERO);
266 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
267 tmp->tm_nodes_max = nodes;
268 tmp->tm_nodes_inuse = 0;
269 tmp->tm_maxfilesize = (u_int64_t)(cnt.v_page_count + get_swpgtotal()) * PAGE_SIZE;
270 LIST_INIT(&tmp->tm_nodes_used);
272 tmp->tm_pages_max = pages;
273 tmp->tm_pages_used = 0;
274 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
275 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
276 sizeof(struct tmpfs_dirent),
277 NULL, NULL, NULL, NULL,
279 tmp->tm_node_pool = uma_zcreate("TMPFS node",
280 sizeof(struct tmpfs_node),
281 tmpfs_node_ctor, tmpfs_node_dtor,
282 tmpfs_node_init, tmpfs_node_fini,
285 /* Allocate the root node. */
286 error = tmpfs_alloc_node(tmp, VDIR, root_uid,
287 root_gid, root_mode & ALLPERMS, NULL, NULL,
290 if (error != 0 || root == NULL) {
291 uma_zdestroy(tmp->tm_node_pool);
292 uma_zdestroy(tmp->tm_dirent_pool);
293 delete_unrhdr(tmp->tm_ino_unr);
294 free(tmp, M_TMPFSMNT);
297 KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
301 mp->mnt_flag |= MNT_LOCAL;
302 mp->mnt_kern_flag |= MNTK_MPSAFE;
306 mp->mnt_stat.f_namemax = MAXNAMLEN;
308 vfs_mountedfrom(mp, "tmpfs");
313 /* --------------------------------------------------------------------- */
317 tmpfs_unmount(struct mount *mp, int mntflags, struct thread *l)
321 struct tmpfs_mount *tmp;
322 struct tmpfs_node *node;
324 /* Handle forced unmounts. */
325 if (mntflags & MNT_FORCE)
328 /* Finalize all pending I/O. */
329 error = vflush(mp, 0, flags, l);
333 tmp = VFS_TO_TMPFS(mp);
335 /* Free all associated data. The loop iterates over the linked list
336 * we have containing all used nodes. For each of them that is
337 * a directory, we free all its directory entries. Note that after
338 * freeing a node, it will automatically go to the available list,
339 * so we will later have to iterate over it to release its items. */
340 node = LIST_FIRST(&tmp->tm_nodes_used);
341 while (node != NULL) {
342 struct tmpfs_node *next;
344 if (node->tn_type == VDIR) {
345 struct tmpfs_dirent *de;
347 de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
349 struct tmpfs_dirent *nde;
351 nde = TAILQ_NEXT(de, td_entries);
352 tmpfs_free_dirent(tmp, de, FALSE);
354 node->tn_size -= sizeof(struct tmpfs_dirent);
358 next = LIST_NEXT(node, tn_entries);
359 tmpfs_free_node(tmp, node);
363 uma_zdestroy(tmp->tm_dirent_pool);
364 uma_zdestroy(tmp->tm_node_pool);
365 delete_unrhdr(tmp->tm_ino_unr);
367 mtx_destroy(&tmp->allnode_lock);
368 MPASS(tmp->tm_pages_used == 0);
369 MPASS(tmp->tm_nodes_inuse == 0);
371 /* Throw away the tmpfs_mount structure. */
372 free(mp->mnt_data, M_TMPFSMNT);
376 mp->mnt_flag &= ~MNT_LOCAL;
381 /* --------------------------------------------------------------------- */
384 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
387 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp, td);
390 (*vpp)->v_vflag |= VV_ROOT;
395 /* --------------------------------------------------------------------- */
398 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
401 struct tmpfs_fid *tfhp;
402 struct tmpfs_mount *tmp;
403 struct tmpfs_node *node;
405 tmp = VFS_TO_TMPFS(mp);
407 tfhp = (struct tmpfs_fid *)fhp;
408 if (tfhp->tf_len != sizeof(struct tmpfs_fid))
411 if (tfhp->tf_id >= tmp->tm_nodes_max)
417 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
418 if (node->tn_id == tfhp->tf_id &&
419 node->tn_gen == tfhp->tf_gen) {
427 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp, curthread));
432 /* --------------------------------------------------------------------- */
436 tmpfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *l)
438 fsfilcnt_t freenodes;
439 struct tmpfs_mount *tmp;
441 tmp = VFS_TO_TMPFS(mp);
443 sbp->f_iosize = PAGE_SIZE;
444 sbp->f_bsize = PAGE_SIZE;
446 sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
447 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
449 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
450 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
452 sbp->f_files = freenodes + tmp->tm_nodes_inuse;
453 sbp->f_ffree = freenodes;
454 /* sbp->f_owner = tmp->tn_uid; */
459 /* --------------------------------------------------------------------- */
462 * tmpfs vfs operations.
465 struct vfsops tmpfs_vfsops = {
466 .vfs_mount = tmpfs_mount,
467 .vfs_unmount = tmpfs_unmount,
468 .vfs_root = tmpfs_root,
469 .vfs_statfs = tmpfs_statfs,
470 .vfs_fhtovp = tmpfs_fhtovp,
472 VFS_SET(tmpfs_vfsops, tmpfs, 0);