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| Current File : //sys/amd64/compile/hs32/modules/usr/src/sys/modules/ubsec/@/fs/tmpfs/tmpfs_vfsops.c |
/* $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/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/fs/tmpfs/tmpfs_vfsops.c 234849 2012-04-30 17:56:49Z gleb $");
#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 <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_param.h>
#include <fs/tmpfs/tmpfs.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");
MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
/* --------------------------------------------------------------------- */
static int tmpfs_mount(struct mount *);
static int tmpfs_unmount(struct mount *, int);
static int tmpfs_root(struct mount *, int flags, struct vnode **);
static int tmpfs_fhtovp(struct mount *, struct fid *, int,
struct vnode **);
static int tmpfs_statfs(struct mount *, struct statfs *);
/* --------------------------------------------------------------------- */
static const char *tmpfs_opts[] = {
"from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export",
NULL
};
/* --------------------------------------------------------------------- */
static int
tmpfs_getopt_size(struct vfsoptlist *opts, const char *name, off_t *value)
{
char *opt_value, *vtp;
quad_t iv;
int error, opt_len;
error = vfs_getopt(opts, name, (void **)&opt_value, &opt_len);
if (error != 0)
return (error);
if (opt_len == 0 || opt_value == NULL)
return (EINVAL);
if (opt_value[0] == '\0' || opt_value[opt_len - 1] != '\0')
return (EINVAL);
iv = strtoq(opt_value, &vtp, 0);
if (vtp == opt_value || (vtp[0] != '\0' && vtp[1] != '\0'))
return (EINVAL);
if (iv < 0)
return (EINVAL);
switch (vtp[0]) {
case 't':
case 'T':
iv *= 1024;
case 'g':
case 'G':
iv *= 1024;
case 'm':
case 'M':
iv *= 1024;
case 'k':
case 'K':
iv *= 1024;
case '\0':
break;
default:
return (EINVAL);
}
*value = iv;
return (0);
}
static int
tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
{
struct tmpfs_node *node = (struct tmpfs_node *)mem;
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 = 0;
return (0);
}
static void
tmpfs_node_dtor(void *mem, int size, void *arg)
{
struct tmpfs_node *node = (struct tmpfs_node *)mem;
node->tn_type = VNON;
}
static int
tmpfs_node_init(void *mem, int size, int flags)
{
struct tmpfs_node *node = (struct tmpfs_node *)mem;
node->tn_id = 0;
mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
node->tn_gen = arc4random();
return (0);
}
static void
tmpfs_node_fini(void *mem, int size)
{
struct tmpfs_node *node = (struct tmpfs_node *)mem;
mtx_destroy(&node->tn_interlock);
}
static int
tmpfs_mount(struct mount *mp)
{
const size_t nodes_per_page = howmany(PAGE_SIZE,
sizeof(struct tmpfs_dirent) + sizeof(struct tmpfs_node));
struct tmpfs_mount *tmp;
struct tmpfs_node *root;
int error;
/* Size counters. */
u_quad_t pages;
off_t nodes_max, size_max, maxfilesize;
/* Root node attributes. */
uid_t root_uid;
gid_t root_gid;
mode_t root_mode;
struct vattr va;
if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
return (EINVAL);
if (mp->mnt_flag & MNT_UPDATE) {
/* XXX: There is no support yet to update file system
* settings. Should be added. */
return EOPNOTSUPP;
}
vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
VOP_UNLOCK(mp->mnt_vnodecovered, 0);
if (error)
return (error);
if (mp->mnt_cred->cr_ruid != 0 ||
vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
root_gid = va.va_gid;
if (mp->mnt_cred->cr_ruid != 0 ||
vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
root_uid = va.va_uid;
if (mp->mnt_cred->cr_ruid != 0 ||
vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
root_mode = va.va_mode;
if (tmpfs_getopt_size(mp->mnt_optnew, "inodes", &nodes_max) != 0)
nodes_max = 0;
if (tmpfs_getopt_size(mp->mnt_optnew, "size", &size_max) != 0)
size_max = 0;
if (tmpfs_getopt_size(mp->mnt_optnew, "maxfilesize", &maxfilesize) != 0)
maxfilesize = 0;
/* Do not allow mounts if we do not have enough memory to preserve
* the minimum reserved pages. */
if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED)
return ENOSPC;
/* Get the maximum number of memory pages this file system is
* allowed to use, based on the maximum size the user passed in
* the mount structure. A value of zero is treated as if the
* maximum available space was requested. */
if (size_max < PAGE_SIZE || size_max > OFF_MAX - PAGE_SIZE ||
(SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX))
pages = SIZE_MAX;
else
pages = howmany(size_max, PAGE_SIZE);
MPASS(pages > 0);
if (nodes_max <= 3) {
if (pages < INT_MAX / nodes_per_page)
nodes_max = pages * nodes_per_page;
else
nodes_max = INT_MAX;
}
if (nodes_max > INT_MAX)
nodes_max = INT_MAX;
MPASS(nodes_max >= 3);
/* Allocate the tmpfs mount structure and fill it. */
tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
M_TMPFSMNT, M_WAITOK | M_ZERO);
mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
tmp->tm_nodes_max = nodes_max;
tmp->tm_nodes_inuse = 0;
tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX;
LIST_INIT(&tmp->tm_nodes_used);
tmp->tm_pages_max = pages;
tmp->tm_pages_used = 0;
tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
sizeof(struct tmpfs_dirent),
NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, 0);
tmp->tm_node_pool = uma_zcreate("TMPFS node",
sizeof(struct tmpfs_node),
tmpfs_node_ctor, tmpfs_node_dtor,
tmpfs_node_init, tmpfs_node_fini,
UMA_ALIGN_PTR, 0);
/* Allocate the root node. */
error = tmpfs_alloc_node(tmp, VDIR, root_uid,
root_gid, root_mode & ALLPERMS, NULL, NULL,
VNOVAL, &root);
if (error != 0 || root == NULL) {
uma_zdestroy(tmp->tm_node_pool);
uma_zdestroy(tmp->tm_dirent_pool);
delete_unrhdr(tmp->tm_ino_unr);
free(tmp, M_TMPFSMNT);
return error;
}
KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
tmp->tm_root = root;
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
mp->mnt_kern_flag |= MNTK_MPSAFE;
MNT_IUNLOCK(mp);
mp->mnt_data = tmp;
mp->mnt_stat.f_namemax = MAXNAMLEN;
vfs_getnewfsid(mp);
vfs_mountedfrom(mp, "tmpfs");
return 0;
}
/* --------------------------------------------------------------------- */
/* ARGSUSED2 */
static int
tmpfs_unmount(struct mount *mp, int mntflags)
{
int error;
int flags = 0;
struct tmpfs_mount *tmp;
struct tmpfs_node *node;
/* Handle forced unmounts. */
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
/* Finalize all pending I/O. */
error = vflush(mp, 0, flags, curthread);
if (error != 0)
return error;
tmp = VFS_TO_TMPFS(mp);
/* Free all associated data. The loop iterates over the linked list
* we have containing all used nodes. For each of them that is
* a directory, we free all its directory entries. Note that after
* freeing a node, it will automatically go to the available list,
* so we will later have to iterate over it to release its items. */
node = LIST_FIRST(&tmp->tm_nodes_used);
while (node != NULL) {
struct tmpfs_node *next;
if (node->tn_type == VDIR) {
struct tmpfs_dirent *de;
de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
while (de != NULL) {
struct tmpfs_dirent *nde;
nde = TAILQ_NEXT(de, td_entries);
tmpfs_free_dirent(tmp, de, FALSE);
de = nde;
node->tn_size -= sizeof(struct tmpfs_dirent);
}
}
next = LIST_NEXT(node, tn_entries);
tmpfs_free_node(tmp, node);
node = next;
}
uma_zdestroy(tmp->tm_dirent_pool);
uma_zdestroy(tmp->tm_node_pool);
delete_unrhdr(tmp->tm_ino_unr);
mtx_destroy(&tmp->allnode_lock);
MPASS(tmp->tm_pages_used == 0);
MPASS(tmp->tm_nodes_inuse == 0);
/* Throw away the tmpfs_mount structure. */
free(mp->mnt_data, M_TMPFSMNT);
mp->mnt_data = NULL;
MNT_ILOCK(mp);
mp->mnt_flag &= ~MNT_LOCAL;
MNT_IUNLOCK(mp);
return 0;
}
/* --------------------------------------------------------------------- */
static int
tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
{
int error;
error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
if (!error)
(*vpp)->v_vflag |= VV_ROOT;
return error;
}
/* --------------------------------------------------------------------- */
static int
tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
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 tmpfs_mount *tmp;
size_t used;
tmp = VFS_TO_TMPFS(mp);
sbp->f_iosize = PAGE_SIZE;
sbp->f_bsize = PAGE_SIZE;
used = tmpfs_pages_used(tmp);
if (tmp->tm_pages_max != SIZE_MAX)
sbp->f_blocks = tmp->tm_pages_max;
else
sbp->f_blocks = used + tmpfs_mem_avail();
if (sbp->f_blocks <= used)
sbp->f_bavail = 0;
else
sbp->f_bavail = sbp->f_blocks - used;
sbp->f_bfree = sbp->f_bavail;
used = tmp->tm_nodes_inuse;
sbp->f_files = tmp->tm_nodes_max;
if (sbp->f_files <= used)
sbp->f_ffree = 0;
else
sbp->f_ffree = sbp->f_files - used;
/* sbp->f_owner = tmp->tn_uid; */
return 0;
}
/* --------------------------------------------------------------------- */
/*
* tmpfs vfs operations.
*/
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_SET(tmpfs_vfsops, tmpfs, 0);