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>
52 #include <sys/kernel.h>
54 #include <sys/systm.h>
55 #include <sys/sysctl.h>
58 #include <vm/vm_object.h>
59 #include <vm/vm_param.h>
61 #include <fs/tmpfs/tmpfs.h>
64 * Default permission for root node
66 #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
68 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
69 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
71 /* --------------------------------------------------------------------- */
73 static int tmpfs_mount(struct mount *);
74 static int tmpfs_unmount(struct mount *, int);
75 static int tmpfs_root(struct mount *, int flags, struct vnode **);
76 static int tmpfs_fhtovp(struct mount *, struct fid *, int,
78 static int tmpfs_statfs(struct mount *, struct statfs *);
80 /* --------------------------------------------------------------------- */
82 static const char *tmpfs_opts[] = {
83 "from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export",
87 static const char *tmpfs_updateopts[] = {
88 "from", "export", NULL
91 /* --------------------------------------------------------------------- */
94 tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
96 struct tmpfs_node *node = (struct tmpfs_node *)mem;
103 node->tn_vnode = NULL;
104 node->tn_vpstate = 0;
110 tmpfs_node_dtor(void *mem, int size, void *arg)
112 struct tmpfs_node *node = (struct tmpfs_node *)mem;
113 node->tn_type = VNON;
117 tmpfs_node_init(void *mem, int size, int flags)
119 struct tmpfs_node *node = (struct tmpfs_node *)mem;
122 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
123 node->tn_gen = arc4random();
129 tmpfs_node_fini(void *mem, int size)
131 struct tmpfs_node *node = (struct tmpfs_node *)mem;
133 mtx_destroy(&node->tn_interlock);
137 tmpfs_mount(struct mount *mp)
139 const size_t nodes_per_page = howmany(PAGE_SIZE,
140 sizeof(struct tmpfs_dirent) + sizeof(struct tmpfs_node));
141 struct tmpfs_mount *tmp;
142 struct tmpfs_node *root;
143 struct thread *td = curthread;
147 off_t nodes_max, size_max, maxfilesize;
149 /* Root node attributes. */
156 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_TMPFS))
159 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
162 if (mp->mnt_flag & MNT_UPDATE) {
163 /* Only support update mounts for certain options. */
164 if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0)
166 if (vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) !=
167 ((struct tmpfs_mount *)mp->mnt_data)->tm_ronly)
172 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
173 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
174 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
178 if (mp->mnt_cred->cr_ruid != 0 ||
179 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
180 root_gid = va.va_gid;
181 if (mp->mnt_cred->cr_ruid != 0 ||
182 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
183 root_uid = va.va_uid;
184 if (mp->mnt_cred->cr_ruid != 0 ||
185 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
186 root_mode = va.va_mode;
187 if (vfs_getopt_size(mp->mnt_optnew, "inodes", &nodes_max) != 0)
189 if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) != 0)
191 if (vfs_getopt_size(mp->mnt_optnew, "maxfilesize", &maxfilesize) != 0)
194 /* Do not allow mounts if we do not have enough memory to preserve
195 * the minimum reserved pages. */
196 if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED)
199 /* Get the maximum number of memory pages this file system is
200 * allowed to use, based on the maximum size the user passed in
201 * the mount structure. A value of zero is treated as if the
202 * maximum available space was requested. */
203 if (size_max < PAGE_SIZE || size_max > OFF_MAX - PAGE_SIZE ||
204 (SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX))
207 pages = howmany(size_max, PAGE_SIZE);
210 if (nodes_max <= 3) {
211 if (pages < INT_MAX / nodes_per_page)
212 nodes_max = pages * nodes_per_page;
216 if (nodes_max > INT_MAX)
218 MPASS(nodes_max >= 3);
220 /* Allocate the tmpfs mount structure and fill it. */
221 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
222 M_TMPFSMNT, M_WAITOK | M_ZERO);
224 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
225 tmp->tm_nodes_max = nodes_max;
226 tmp->tm_nodes_inuse = 0;
227 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX;
228 LIST_INIT(&tmp->tm_nodes_used);
230 tmp->tm_pages_max = pages;
231 tmp->tm_pages_used = 0;
232 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
233 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
234 sizeof(struct tmpfs_dirent),
235 NULL, NULL, NULL, NULL,
237 tmp->tm_node_pool = uma_zcreate("TMPFS node",
238 sizeof(struct tmpfs_node),
239 tmpfs_node_ctor, tmpfs_node_dtor,
240 tmpfs_node_init, tmpfs_node_fini,
242 tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
244 /* Allocate the root node. */
245 error = tmpfs_alloc_node(tmp, VDIR, root_uid,
246 root_gid, root_mode & ALLPERMS, NULL, NULL,
249 if (error != 0 || root == NULL) {
250 uma_zdestroy(tmp->tm_node_pool);
251 uma_zdestroy(tmp->tm_dirent_pool);
252 delete_unrhdr(tmp->tm_ino_unr);
253 free(tmp, M_TMPFSMNT);
256 KASSERT(root->tn_id == 2,
257 ("tmpfs root with invalid ino: %ju", (uintmax_t)root->tn_id));
261 mp->mnt_flag |= MNT_LOCAL;
265 mp->mnt_stat.f_namemax = MAXNAMLEN;
267 vfs_mountedfrom(mp, "tmpfs");
272 /* --------------------------------------------------------------------- */
276 tmpfs_unmount(struct mount *mp, int mntflags)
280 struct tmpfs_mount *tmp;
281 struct tmpfs_node *node;
283 /* Handle forced unmounts. */
284 if (mntflags & MNT_FORCE)
287 /* Finalize all pending I/O. */
288 error = vflush(mp, 0, flags, curthread);
292 tmp = VFS_TO_TMPFS(mp);
294 /* Free all associated data. The loop iterates over the linked list
295 * we have containing all used nodes. For each of them that is
296 * a directory, we free all its directory entries. Note that after
297 * freeing a node, it will automatically go to the available list,
298 * so we will later have to iterate over it to release its items. */
299 node = LIST_FIRST(&tmp->tm_nodes_used);
300 while (node != NULL) {
301 struct tmpfs_node *next;
303 if (node->tn_type == VDIR)
304 tmpfs_dir_destroy(tmp, node);
306 next = LIST_NEXT(node, tn_entries);
307 tmpfs_free_node(tmp, node);
311 uma_zdestroy(tmp->tm_dirent_pool);
312 uma_zdestroy(tmp->tm_node_pool);
313 delete_unrhdr(tmp->tm_ino_unr);
315 mtx_destroy(&tmp->allnode_lock);
316 MPASS(tmp->tm_pages_used == 0);
317 MPASS(tmp->tm_nodes_inuse == 0);
319 /* Throw away the tmpfs_mount structure. */
320 free(mp->mnt_data, M_TMPFSMNT);
324 mp->mnt_flag &= ~MNT_LOCAL;
329 /* --------------------------------------------------------------------- */
332 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
335 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
338 (*vpp)->v_vflag |= VV_ROOT;
343 /* --------------------------------------------------------------------- */
346 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
350 struct tmpfs_fid *tfhp;
351 struct tmpfs_mount *tmp;
352 struct tmpfs_node *node;
354 tmp = VFS_TO_TMPFS(mp);
356 tfhp = (struct tmpfs_fid *)fhp;
357 if (tfhp->tf_len != sizeof(struct tmpfs_fid))
360 if (tfhp->tf_id >= tmp->tm_nodes_max)
366 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
367 if (node->tn_id == tfhp->tf_id &&
368 node->tn_gen == tfhp->tf_gen) {
376 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp));
381 /* --------------------------------------------------------------------- */
385 tmpfs_statfs(struct mount *mp, struct statfs *sbp)
387 struct tmpfs_mount *tmp;
390 tmp = VFS_TO_TMPFS(mp);
392 sbp->f_iosize = PAGE_SIZE;
393 sbp->f_bsize = PAGE_SIZE;
395 used = tmpfs_pages_used(tmp);
396 if (tmp->tm_pages_max != SIZE_MAX)
397 sbp->f_blocks = tmp->tm_pages_max;
399 sbp->f_blocks = used + tmpfs_mem_avail();
400 if (sbp->f_blocks <= used)
403 sbp->f_bavail = sbp->f_blocks - used;
404 sbp->f_bfree = sbp->f_bavail;
405 used = tmp->tm_nodes_inuse;
406 sbp->f_files = tmp->tm_nodes_max;
407 if (sbp->f_files <= used)
410 sbp->f_ffree = sbp->f_files - used;
411 /* sbp->f_owner = tmp->tn_uid; */
416 /* --------------------------------------------------------------------- */
419 * tmpfs vfs operations.
422 struct vfsops tmpfs_vfsops = {
423 .vfs_mount = tmpfs_mount,
424 .vfs_unmount = tmpfs_unmount,
425 .vfs_root = tmpfs_root,
426 .vfs_statfs = tmpfs_statfs,
427 .vfs_fhtovp = tmpfs_fhtovp,
429 VFS_SET(tmpfs_vfsops, tmpfs, VFCF_JAIL);