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tmpfs_vfsops.c
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tmpfs_vfsops.c
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/* $NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $ */
/*-
* Copyright (c) 2005 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Julio M. Merino Vidal, developed as part of Google's Summer of Code
* 2005 program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Efficient memory file system.
*
* tmpfs is a file system that uses NetBSD's virtual memory sub-system
* (the well-known UVM) to store file data and metadata in an efficient
* way. This means that it does not follow the structure of an on-disk
* file system because it simply does not need to. Instead, it uses
* memory-specific data structures and algorithms to automatically
* allocate and release resources.
*/
#include <sys/conf.h>
#include <sys/param.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/objcache.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_param.h>
#include <vfs/tmpfs/tmpfs.h>
#include <vfs/tmpfs/tmpfs_vnops.h>
#include <vfs/tmpfs/tmpfs_args.h>
/*
* Default permission for root node
*/
#define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
/* --------------------------------------------------------------------- */
static int tmpfs_mount(struct mount *, char *, caddr_t, struct ucred *);
static int tmpfs_unmount(struct mount *, int);
static int tmpfs_root(struct mount *, struct vnode **);
static int tmpfs_fhtovp(struct mount *, struct vnode *, struct fid *, struct vnode **);
static int tmpfs_statfs(struct mount *, struct statfs *, struct ucred *cred);
/* --------------------------------------------------------------------- */
int
tmpfs_node_ctor(void *obj, void *privdata, int flags)
{
struct tmpfs_node *node = (struct tmpfs_node *)obj;
node->tn_gen++;
node->tn_size = 0;
node->tn_status = 0;
node->tn_flags = 0;
node->tn_links = 0;
node->tn_vnode = NULL;
node->tn_vpstate = TMPFS_VNODE_WANT;
bzero(&node->tn_spec, sizeof(node->tn_spec));
return (1);
}
static void
tmpfs_node_dtor(void *obj, void *privdata)
{
struct tmpfs_node *node = (struct tmpfs_node *)obj;
node->tn_type = VNON;
node->tn_vpstate = TMPFS_VNODE_DOOMED;
}
static void*
tmpfs_node_init(void *args, int flags)
{
struct tmpfs_node *node = (struct tmpfs_node *)objcache_malloc_alloc(args, flags);
if (node == NULL)
return (NULL);
node->tn_id = 0;
lockinit(&node->tn_interlock, "tmpfs node interlock", 0, LK_CANRECURSE);
node->tn_gen = karc4random();
return node;
}
static void
tmpfs_node_fini(void *obj, void *args)
{
struct tmpfs_node *node = (struct tmpfs_node *)obj;
lockuninit(&node->tn_interlock);
objcache_malloc_free(obj, args);
}
static int
tmpfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
{
struct tmpfs_mount *tmp;
struct tmpfs_node *root;
struct tmpfs_args args;
vm_pindex_t pages;
vm_pindex_t pages_limit;
ino_t nodes;
u_int64_t maxfsize;
int error;
/* Size counters. */
ino_t nodes_max;
off_t size_max;
size_t maxfsize_max;
size_t size;
/* Root node attributes. */
uid_t root_uid = cred->cr_uid;
gid_t root_gid = cred->cr_gid;
mode_t root_mode = (VREAD | VWRITE);
if (mp->mnt_flag & MNT_UPDATE) {
/* XXX: There is no support yet to update file system
* settings. Should be added. */
return EOPNOTSUPP;
}
/*
* mount info
*/
bzero(&args, sizeof(args));
size_max = 0;
nodes_max = 0;
maxfsize_max = 0;
if (path) {
if (data) {
error = copyin(data, &args, sizeof(args));
if (error)
return (error);
}
size_max = args.ta_size_max;
nodes_max = args.ta_nodes_max;
maxfsize_max = args.ta_maxfsize_max;
root_uid = args.ta_root_uid;
root_gid = args.ta_root_gid;
root_mode = args.ta_root_mode;
}
/*
* If mount by non-root, then verify that user has necessary
* permissions on the device.
*/
if (cred->cr_uid != 0) {
root_mode = VREAD;
if ((mp->mnt_flag & MNT_RDONLY) == 0)
root_mode |= VWRITE;
}
pages_limit = vm_swap_max + vmstats.v_page_count / 2;
if (size_max == 0) {
pages = pages_limit / 2;
} else if (size_max < PAGE_SIZE) {
pages = 1;
} else if (OFF_TO_IDX(size_max) > pages_limit) {
/*
* do not force pages = pages_limit for this case, otherwise
* we might not honor tmpfs size requests from /etc/fstab
* during boot because they are mounted prior to swap being
* turned on.
*/
pages = OFF_TO_IDX(size_max);
} else {
pages = OFF_TO_IDX(size_max);
}
if (nodes_max == 0)
nodes = 3 + pages * PAGE_SIZE / 1024;
else if (nodes_max < 3)
nodes = 3;
else if (nodes_max > pages)
nodes = pages;
else
nodes = nodes_max;
maxfsize = IDX_TO_OFF(pages_limit);
if (maxfsize_max != 0 && maxfsize > maxfsize_max)
maxfsize = maxfsize_max;
/* Allocate the tmpfs mount structure and fill it. */
tmp = kmalloc(sizeof(*tmp), M_TMPFSMNT, M_WAITOK | M_ZERO);
lockinit(&(tmp->allnode_lock), "tmpfs allnode lock", 0, LK_CANRECURSE);
tmp->tm_nodes_max = nodes;
tmp->tm_nodes_inuse = 0;
tmp->tm_maxfilesize = maxfsize;
LIST_INIT(&tmp->tm_nodes_used);
tmp->tm_pages_max = pages;
tmp->tm_pages_used = 0;
kmalloc_create(&tmp->tm_node_zone, "tmpfs node");
kmalloc_create(&tmp->tm_dirent_zone, "tmpfs dirent");
kmalloc_create(&tmp->tm_name_zone, "tmpfs name zone");
kmalloc_raise_limit(tmp->tm_node_zone, sizeof(struct tmpfs_node) *
tmp->tm_nodes_max);
tmp->tm_node_zone_malloc_args.objsize = sizeof(struct tmpfs_node);
tmp->tm_node_zone_malloc_args.mtype = tmp->tm_node_zone;
tmp->tm_dirent_zone_malloc_args.objsize = sizeof(struct tmpfs_dirent);
tmp->tm_dirent_zone_malloc_args.mtype = tmp->tm_dirent_zone;
tmp->tm_dirent_pool = objcache_create( "tmpfs dirent cache",
0, 0,
NULL, NULL, NULL,
objcache_malloc_alloc, objcache_malloc_free,
&tmp->tm_dirent_zone_malloc_args);
tmp->tm_node_pool = objcache_create( "tmpfs node cache",
0, 0,
tmpfs_node_ctor, tmpfs_node_dtor, NULL,
tmpfs_node_init, tmpfs_node_fini,
&tmp->tm_node_zone_malloc_args);
tmp->tm_ino = 2;
/* Allocate the root node. */
error = tmpfs_alloc_node(tmp, VDIR, root_uid, root_gid,
root_mode & ALLPERMS, NULL, NULL,
VNOVAL, VNOVAL, &root);
/*
* We are backed by swap, set snocache chflags flag so we
* don't trip over swapcache.
*/
root->tn_flags = SF_NOCACHE;
if (error != 0 || root == NULL) {
objcache_destroy(tmp->tm_node_pool);
objcache_destroy(tmp->tm_dirent_pool);
kfree(tmp, M_TMPFSMNT);
return error;
}
KASSERT(root->tn_id >= 0, ("tmpfs root with invalid ino: %d", (int)root->tn_id));
tmp->tm_root = root;
mp->mnt_flag |= MNT_LOCAL;
#if 0
mp->mnt_kern_flag |= MNTK_RD_MPSAFE | MNTK_WR_MPSAFE | MNTK_GA_MPSAFE |
MNTK_IN_MPSAFE | MNTK_SG_MPSAFE;
#endif
mp->mnt_kern_flag |= MNTK_RD_MPSAFE | MNTK_GA_MPSAFE | MNTK_SG_MPSAFE;
mp->mnt_kern_flag |= MNTK_WR_MPSAFE;
mp->mnt_kern_flag |= MNTK_NOMSYNC;
mp->mnt_data = (qaddr_t)tmp;
vfs_getnewfsid(mp);
vfs_add_vnodeops(mp, &tmpfs_vnode_vops, &mp->mnt_vn_norm_ops);
vfs_add_vnodeops(mp, &tmpfs_fifo_vops, &mp->mnt_vn_fifo_ops);
copystr("tmpfs", mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
bzero(mp->mnt_stat.f_mntfromname +size, MNAMELEN - size);
bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
copyinstr(path, mp->mnt_stat.f_mntonname,
sizeof(mp->mnt_stat.f_mntonname) -1,
&size);
tmpfs_statfs(mp, &mp->mnt_stat, cred);
return 0;
}
/* --------------------------------------------------------------------- */
/* ARGSUSED2 */
static int
tmpfs_unmount(struct mount *mp, int mntflags)
{
int error;
int flags = 0;
int found;
struct tmpfs_mount *tmp;
struct tmpfs_node *node;
/* Handle forced unmounts. */
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
tmp = VFS_TO_TMPFS(mp);
/*
* Finalize all pending I/O. In the case of tmpfs we want
* to throw all the data away so clean out the buffer cache
* and vm objects before calling vflush().
*/
LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
if (node->tn_type == VREG && node->tn_vnode) {
++node->tn_links;
TMPFS_NODE_LOCK(node);
vx_get(node->tn_vnode);
tmpfs_truncate(node->tn_vnode, 0);
vx_put(node->tn_vnode);
TMPFS_NODE_UNLOCK(node);
--node->tn_links;
}
}
error = vflush(mp, 0, flags);
if (error != 0)
return error;
/*
* First pass get rid of all the directory entries and
* vnode associations. The directory structure will
* remain via the extra link count representing tn_dir.tn_parent.
*
* No vnodes should remain after the vflush above.
*/
LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
++node->tn_links;
TMPFS_NODE_LOCK(node);
if (node->tn_type == VDIR) {
struct tmpfs_dirent *de;
while (!TAILQ_EMPTY(&node->tn_dir.tn_dirhead)) {
de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
tmpfs_dir_detach(node, de);
tmpfs_free_dirent(tmp, de);
node->tn_size -= sizeof(struct tmpfs_dirent);
}
}
KKASSERT(node->tn_vnode == NULL);
#if 0
vp = node->tn_vnode;
if (vp != NULL) {
tmpfs_free_vp(vp);
vrecycle(vp);
node->tn_vnode = NULL;
}
#endif
TMPFS_NODE_UNLOCK(node);
--node->tn_links;
}
/*
* Now get rid of all nodes. We can remove any node with a
* link count of 0 or any directory node with a link count of
* 1. The parents will not be destroyed until all their children
* have been destroyed.
*
* Recursion in tmpfs_free_node() can further modify the list so
* we cannot use a next pointer here.
*
* The root node will be destroyed by this loop (it will be last).
*/
while (!LIST_EMPTY(&tmp->tm_nodes_used)) {
found = 0;
LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
if (node->tn_links == 0 ||
(node->tn_links == 1 && node->tn_type == VDIR)) {
TMPFS_NODE_LOCK(node);
tmpfs_free_node(tmp, node);
/* eats lock */
found = 1;
break;
}
}
if (found == 0) {
kprintf("tmpfs: Cannot free entire node tree!");
break;
}
}
KKASSERT(tmp->tm_root == NULL);
objcache_destroy(tmp->tm_dirent_pool);
objcache_destroy(tmp->tm_node_pool);
kmalloc_destroy(&tmp->tm_name_zone);
kmalloc_destroy(&tmp->tm_dirent_zone);
kmalloc_destroy(&tmp->tm_node_zone);
tmp->tm_node_zone = tmp->tm_dirent_zone = NULL;
lockuninit(&tmp->allnode_lock);
KKASSERT(tmp->tm_pages_used == 0);
KKASSERT(tmp->tm_nodes_inuse == 0);
/* Throw away the tmpfs_mount structure. */
kfree(tmp, M_TMPFSMNT);
mp->mnt_data = NULL;
mp->mnt_flag &= ~MNT_LOCAL;
return 0;
}
/* --------------------------------------------------------------------- */
static int
tmpfs_root(struct mount *mp, struct vnode **vpp)
{
struct tmpfs_mount *tmp;
int error;
tmp = VFS_TO_TMPFS(mp);
if (tmp->tm_root == NULL) {
kprintf("tmpfs_root: called without root node %p\n", mp);
print_backtrace(-1);
*vpp = NULL;
error = EINVAL;
} else {
error = tmpfs_alloc_vp(mp, tmp->tm_root, LK_EXCLUSIVE, vpp);
(*vpp)->v_flag |= VROOT;
(*vpp)->v_type = VDIR;
}
return error;
}
/* --------------------------------------------------------------------- */
static int
tmpfs_fhtovp(struct mount *mp, struct vnode *rootvp, struct fid *fhp, struct vnode **vpp)
{
boolean_t found;
struct tmpfs_fid *tfhp;
struct tmpfs_mount *tmp;
struct tmpfs_node *node;
tmp = VFS_TO_TMPFS(mp);
tfhp = (struct tmpfs_fid *)fhp;
if (tfhp->tf_len != sizeof(struct tmpfs_fid))
return EINVAL;
if (tfhp->tf_id >= tmp->tm_nodes_max)
return EINVAL;
found = FALSE;
TMPFS_LOCK(tmp);
LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
if (node->tn_id == tfhp->tf_id &&
node->tn_gen == tfhp->tf_gen) {
found = TRUE;
break;
}
}
TMPFS_UNLOCK(tmp);
if (found)
return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp));
return (EINVAL);
}
/* --------------------------------------------------------------------- */
/* ARGSUSED2 */
static int
tmpfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
{
fsfilcnt_t freenodes;
struct tmpfs_mount *tmp;
tmp = VFS_TO_TMPFS(mp);
sbp->f_iosize = PAGE_SIZE;
sbp->f_bsize = PAGE_SIZE;
sbp->f_blocks = tmp->tm_pages_max;
sbp->f_bavail = tmp->tm_pages_max - tmp->tm_pages_used;
sbp->f_bfree = sbp->f_bavail;
freenodes = tmp->tm_nodes_max - tmp->tm_nodes_inuse;
sbp->f_files = freenodes + tmp->tm_nodes_inuse;
sbp->f_ffree = freenodes;
sbp->f_owner = tmp->tm_root->tn_uid;
return 0;
}
/* --------------------------------------------------------------------- */
static int
tmpfs_vptofh(struct vnode *vp, struct fid *fhp)
{
struct tmpfs_node *node;
struct tmpfs_fid tfh;
node = VP_TO_TMPFS_NODE(vp);
memset(&tfh, 0, sizeof(tfh));
tfh.tf_len = sizeof(struct tmpfs_fid);
tfh.tf_gen = node->tn_gen;
tfh.tf_id = node->tn_id;
memcpy(fhp, &tfh, sizeof(tfh));
return (0);
}
/* --------------------------------------------------------------------- */
static int
tmpfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp,
struct ucred **credanonp)
{
struct tmpfs_mount *tmp;
struct netcred *nc;
tmp = (struct tmpfs_mount *) mp->mnt_data;
nc = vfs_export_lookup(mp, &tmp->tm_export, nam);
if (nc == NULL)
return (EACCES);
*exflagsp = nc->netc_exflags;
*credanonp = &nc->netc_anon;
return (0);
}
/* --------------------------------------------------------------------- */
/*
* tmpfs vfs operations.
*/
static struct vfsops tmpfs_vfsops = {
.vfs_mount = tmpfs_mount,
.vfs_unmount = tmpfs_unmount,
.vfs_root = tmpfs_root,
.vfs_statfs = tmpfs_statfs,
.vfs_fhtovp = tmpfs_fhtovp,
.vfs_vptofh = tmpfs_vptofh,
.vfs_sync = vfs_stdsync,
.vfs_checkexp = tmpfs_checkexp,
};
VFS_SET(tmpfs_vfsops, tmpfs, 0);
MODULE_VERSION(tmpfs, 1);