- 根目录:
- fs
- afs
- super.c
/* AFS superblock handling
*
* Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
*
* This software may be freely redistributed under the terms of the
* GNU General Public License.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Authors: David Howells <dhowells@redhat.com>
* David Woodhouse <dwmw2@infradead.org>
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/parser.h>
#include <linux/statfs.h>
#include <linux/sched.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include "internal.h"
#define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
static void afs_i_init_once(void *foo);
static struct dentry *afs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data);
static void afs_kill_super(struct super_block *sb);
static struct inode *afs_alloc_inode(struct super_block *sb);
static void afs_destroy_inode(struct inode *inode);
static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
struct file_system_type afs_fs_type = {
.owner = THIS_MODULE,
.name = "afs",
.mount = afs_mount,
.kill_sb = afs_kill_super,
.fs_flags = 0,
};
MODULE_ALIAS_FS("afs");
static const struct super_operations afs_super_ops = {
.statfs = afs_statfs,
.alloc_inode = afs_alloc_inode,
.drop_inode = afs_drop_inode,
.destroy_inode = afs_destroy_inode,
.evict_inode = afs_evict_inode,
.show_options = generic_show_options,
};
static struct kmem_cache *afs_inode_cachep;
static atomic_t afs_count_active_inodes;
enum {
afs_no_opt,
afs_opt_cell,
afs_opt_rwpath,
afs_opt_vol,
afs_opt_autocell,
};
static const match_table_t afs_options_list = {
{ afs_opt_cell, "cell=%s" },
{ afs_opt_rwpath, "rwpath" },
{ afs_opt_vol, "vol=%s" },
{ afs_opt_autocell, "autocell" },
{ afs_no_opt, NULL },
};
/*
* initialise the filesystem
*/
int __init afs_fs_init(void)
{
int ret;
_enter("");
/* create ourselves an inode cache */
atomic_set(&afs_count_active_inodes, 0);
ret = -ENOMEM;
afs_inode_cachep = kmem_cache_create("afs_inode_cache",
sizeof(struct afs_vnode),
0,
SLAB_HWCACHE_ALIGN,
afs_i_init_once);
if (!afs_inode_cachep) {
printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
return ret;
}
/* now export our filesystem to lesser mortals */
ret = register_filesystem(&afs_fs_type);
if (ret < 0) {
kmem_cache_destroy(afs_inode_cachep);
_leave(" = %d", ret);
return ret;
}
_leave(" = 0");
return 0;
}
/*
* clean up the filesystem
*/
void __exit afs_fs_exit(void)
{
_enter("");
afs_mntpt_kill_timer();
unregister_filesystem(&afs_fs_type);
if (atomic_read(&afs_count_active_inodes) != 0) {
printk("kAFS: %d active inode objects still present\n",
atomic_read(&afs_count_active_inodes));
BUG();
}
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(afs_inode_cachep);
_leave("");
}
/*
* parse the mount options
* - this function has been shamelessly adapted from the ext3 fs which
* shamelessly adapted it from the msdos fs
*/
static int afs_parse_options(struct afs_mount_params *params,
char *options, const char **devname)
{
struct afs_cell *cell;
substring_t args[MAX_OPT_ARGS];
char *p;
int token;
_enter("%s", options);
options[PAGE_SIZE - 1] = 0;
while ((p = strsep(&options, ","))) {
if (!*p)
continue;
token = match_token(p, afs_options_list, args);
switch (token) {
case afs_opt_cell:
cell = afs_cell_lookup(args[0].from,
args[0].to - args[0].from,
false);
if (IS_ERR(cell))
return PTR_ERR(cell);
afs_put_cell(params->cell);
params->cell = cell;
break;
case afs_opt_rwpath:
params->rwpath = 1;
break;
case afs_opt_vol:
*devname = args[0].from;
break;
case afs_opt_autocell:
params->autocell = 1;
break;
default:
printk(KERN_ERR "kAFS:"
" Unknown or invalid mount option: '%s'\n", p);
return -EINVAL;
}
}
_leave(" = 0");
return 0;
}
/*
* parse a device name to get cell name, volume name, volume type and R/W
* selector
* - this can be one of the following:
* "%[cell:]volume[.]" R/W volume
* "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
* or R/W (rwpath=1) volume
* "%[cell:]volume.readonly" R/O volume
* "#[cell:]volume.readonly" R/O volume
* "%[cell:]volume.backup" Backup volume
* "#[cell:]volume.backup" Backup volume
*/
static int afs_parse_device_name(struct afs_mount_params *params,
const char *name)
{
struct afs_cell *cell;
const char *cellname, *suffix;
int cellnamesz;
_enter(",%s", name);
if (!name) {
printk(KERN_ERR "kAFS: no volume name specified\n");
return -EINVAL;
}
if ((name[0] != '%' && name[0] != '#') || !name[1]) {
printk(KERN_ERR "kAFS: unparsable volume name\n");
return -EINVAL;
}
/* determine the type of volume we're looking for */
params->type = AFSVL_ROVOL;
params->force = false;
if (params->rwpath || name[0] == '%') {
params->type = AFSVL_RWVOL;
params->force = true;
}
name++;
/* split the cell name out if there is one */
params->volname = strchr(name, ':');
if (params->volname) {
cellname = name;
cellnamesz = params->volname - name;
params->volname++;
} else {
params->volname = name;
cellname = NULL;
cellnamesz = 0;
}
/* the volume type is further affected by a possible suffix */
suffix = strrchr(params->volname, '.');
if (suffix) {
if (strcmp(suffix, ".readonly") == 0) {
params->type = AFSVL_ROVOL;
params->force = true;
} else if (strcmp(suffix, ".backup") == 0) {
params->type = AFSVL_BACKVOL;
params->force = true;
} else if (suffix[1] == 0) {
} else {
suffix = NULL;
}
}
params->volnamesz = suffix ?
suffix - params->volname : strlen(params->volname);
_debug("cell %*.*s [%p]",
cellnamesz, cellnamesz, cellname ?: "", params->cell);
/* lookup the cell record */
if (cellname || !params->cell) {
cell = afs_cell_lookup(cellname, cellnamesz, true);
if (IS_ERR(cell)) {
printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
cellnamesz, cellnamesz, cellname ?: "");
return PTR_ERR(cell);
}
afs_put_cell(params->cell);
params->cell = cell;
}
_debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
params->cell->name, params->cell,
params->volnamesz, params->volnamesz, params->volname,
suffix ?: "-", params->type, params->force ? " FORCE" : "");
return 0;
}
/*
* check a superblock to see if it's the one we're looking for
*/
static int afs_test_super(struct super_block *sb, void *data)
{
struct afs_super_info *as1 = data;
struct afs_super_info *as = sb->s_fs_info;
return as->volume == as1->volume;
}
static int afs_set_super(struct super_block *sb, void *data)
{
sb->s_fs_info = data;
return set_anon_super(sb, NULL);
}
/*
* fill in the superblock
*/
static int afs_fill_super(struct super_block *sb,
struct afs_mount_params *params)
{
struct afs_super_info *as = sb->s_fs_info;
struct afs_fid fid;
struct inode *inode = NULL;
int ret;
_enter("");
/* fill in the superblock */
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = AFS_FS_MAGIC;
sb->s_op = &afs_super_ops;
sb->s_bdi = &as->volume->bdi;
strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
/* allocate the root inode and dentry */
fid.vid = as->volume->vid;
fid.vnode = 1;
fid.unique = 1;
inode = afs_iget(sb, params->key, &fid, NULL, NULL);
if (IS_ERR(inode))
return PTR_ERR(inode);
if (params->autocell)
set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
ret = -ENOMEM;
sb->s_root = d_make_root(inode);
if (!sb->s_root)
goto error;
sb->s_d_op = &afs_fs_dentry_operations;
_leave(" = 0");
return 0;
error:
_leave(" = %d", ret);
return ret;
}
/*
* get an AFS superblock
*/
static struct dentry *afs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *options)
{
struct afs_mount_params params;
struct super_block *sb;
struct afs_volume *vol;
struct key *key;
char *new_opts = kstrdup(options, GFP_KERNEL);
struct afs_super_info *as;
int ret;
_enter(",,%s,%p", dev_name, options);
memset(¶ms, 0, sizeof(params));
ret = -EINVAL;
if (current->nsproxy->net_ns != &init_net)
goto error;
/* parse the options and device name */
if (options) {
ret = afs_parse_options(¶ms, options, &dev_name);
if (ret < 0)
goto error;
}
ret = afs_parse_device_name(¶ms, dev_name);
if (ret < 0)
goto error;
/* try and do the mount securely */
key = afs_request_key(params.cell);
if (IS_ERR(key)) {
_leave(" = %ld [key]", PTR_ERR(key));
ret = PTR_ERR(key);
goto error;
}
params.key = key;
/* parse the device name */
vol = afs_volume_lookup(¶ms);
if (IS_ERR(vol)) {
ret = PTR_ERR(vol);
goto error;
}
/* allocate a superblock info record */
as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (!as) {
ret = -ENOMEM;
afs_put_volume(vol);
goto error;
}
as->volume = vol;
/* allocate a deviceless superblock */
sb = sget(fs_type, afs_test_super, afs_set_super, flags, as);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
afs_put_volume(vol);
kfree(as);
goto error;
}
if (!sb->s_root) {
/* initial superblock/root creation */
_debug("create");
ret = afs_fill_super(sb, ¶ms);
if (ret < 0) {
deactivate_locked_super(sb);
goto error;
}
save_mount_options(sb, new_opts);
sb->s_flags |= MS_ACTIVE;
} else {
_debug("reuse");
ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
afs_put_volume(vol);
kfree(as);
}
afs_put_cell(params.cell);
kfree(new_opts);
_leave(" = 0 [%p]", sb);
return dget(sb->s_root);
error:
afs_put_cell(params.cell);
key_put(params.key);
kfree(new_opts);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
static void afs_kill_super(struct super_block *sb)
{
struct afs_super_info *as = sb->s_fs_info;
kill_anon_super(sb);
afs_put_volume(as->volume);
kfree(as);
}
/*
* initialise an inode cache slab element prior to any use
*/
static void afs_i_init_once(void *_vnode)
{
struct afs_vnode *vnode = _vnode;
memset(vnode, 0, sizeof(*vnode));
inode_init_once(&vnode->vfs_inode);
init_waitqueue_head(&vnode->update_waitq);
mutex_init(&vnode->permits_lock);
mutex_init(&vnode->validate_lock);
spin_lock_init(&vnode->writeback_lock);
spin_lock_init(&vnode->lock);
INIT_LIST_HEAD(&vnode->writebacks);
INIT_LIST_HEAD(&vnode->pending_locks);
INIT_LIST_HEAD(&vnode->granted_locks);
INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
}
/*
* allocate an AFS inode struct from our slab cache
*/
static struct inode *afs_alloc_inode(struct super_block *sb)
{
struct afs_vnode *vnode;
vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
if (!vnode)
return NULL;
atomic_inc(&afs_count_active_inodes);
memset(&vnode->fid, 0, sizeof(vnode->fid));
memset(&vnode->status, 0, sizeof(vnode->status));
vnode->volume = NULL;
vnode->update_cnt = 0;
vnode->flags = 1 << AFS_VNODE_UNSET;
vnode->cb_promised = false;
_leave(" = %p", &vnode->vfs_inode);
return &vnode->vfs_inode;
}
static void afs_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
struct afs_vnode *vnode = AFS_FS_I(inode);
kmem_cache_free(afs_inode_cachep, vnode);
}
/*
* destroy an AFS inode struct
*/
static void afs_destroy_inode(struct inode *inode)
{
struct afs_vnode *vnode = AFS_FS_I(inode);
_enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
_debug("DESTROY INODE %p", inode);
ASSERTCMP(vnode->server, ==, NULL);
call_rcu(&inode->i_rcu, afs_i_callback);
atomic_dec(&afs_count_active_inodes);
}
/*
* return information about an AFS volume
*/
static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct afs_volume_status vs;
struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
struct key *key;
int ret;
key = afs_request_key(vnode->volume->cell);
if (IS_ERR(key))
return PTR_ERR(key);
ret = afs_vnode_get_volume_status(vnode, key, &vs);
key_put(key);
if (ret < 0) {
_leave(" = %d", ret);
return ret;
}
buf->f_type = dentry->d_sb->s_magic;
buf->f_bsize = AFS_BLOCK_SIZE;
buf->f_namelen = AFSNAMEMAX - 1;
if (vs.max_quota == 0)
buf->f_blocks = vs.part_max_blocks;
else
buf->f_blocks = vs.max_quota;
buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
return 0;
}