WSL2-Linux-Kernel/fs/afs/super.c

442 строки
10 KiB
C

/*
* Copyright (c) 2002 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@cambridge.redhat.com>
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include "vnode.h"
#include "volume.h"
#include "cell.h"
#include "cmservice.h"
#include "fsclient.h"
#include "super.h"
#include "internal.h"
#define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
struct afs_mount_params {
int rwpath;
struct afs_cell *default_cell;
struct afs_volume *volume;
};
static void afs_i_init_once(void *foo, kmem_cache_t *cachep,
unsigned long flags);
static struct super_block *afs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data);
static struct inode *afs_alloc_inode(struct super_block *sb);
static void afs_put_super(struct super_block *sb);
static void afs_destroy_inode(struct inode *inode);
static struct file_system_type afs_fs_type = {
.owner = THIS_MODULE,
.name = "afs",
.get_sb = afs_get_sb,
.kill_sb = kill_anon_super,
.fs_flags = FS_BINARY_MOUNTDATA,
};
static struct super_operations afs_super_ops = {
.statfs = simple_statfs,
.alloc_inode = afs_alloc_inode,
.drop_inode = generic_delete_inode,
.destroy_inode = afs_destroy_inode,
.clear_inode = afs_clear_inode,
.put_super = afs_put_super,
};
static kmem_cache_t *afs_inode_cachep;
static atomic_t afs_count_active_inodes;
/*****************************************************************************/
/*
* initialise the filesystem
*/
int __init afs_fs_init(void)
{
int ret;
_enter("");
afs_timer_init(&afs_mntpt_expiry_timer, &afs_mntpt_expiry_timer_ops);
/* 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,
NULL);
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);
kleave(" = %d", ret);
return ret;
}
kleave(" = 0");
return 0;
} /* end afs_fs_init() */
/*****************************************************************************/
/*
* clean up the filesystem
*/
void __exit afs_fs_exit(void)
{
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();
}
kmem_cache_destroy(afs_inode_cachep);
} /* end afs_fs_exit() */
/*****************************************************************************/
/*
* check that an argument has a value
*/
static int want_arg(char **_value, const char *option)
{
if (!_value || !*_value || !**_value) {
printk(KERN_NOTICE "kAFS: %s: argument missing\n", option);
return 0;
}
return 1;
} /* end want_arg() */
/*****************************************************************************/
/*
* check that there's no subsequent value
*/
static int want_no_value(char *const *_value, const char *option)
{
if (*_value && **_value) {
printk(KERN_NOTICE "kAFS: %s: Invalid argument: %s\n",
option, *_value);
return 0;
}
return 1;
} /* end want_no_value() */
/*****************************************************************************/
/*
* 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_super_parse_options(struct afs_mount_params *params,
char *options,
const char **devname)
{
char *key, *value;
int ret;
_enter("%s", options);
options[PAGE_SIZE - 1] = 0;
ret = 0;
while ((key = strsep(&options, ",")) != 0)
{
value = strchr(key, '=');
if (value)
*value++ = 0;
printk("kAFS: KEY: %s, VAL:%s\n", key, value ?: "-");
if (strcmp(key, "rwpath") == 0) {
if (!want_no_value(&value, "rwpath"))
return -EINVAL;
params->rwpath = 1;
continue;
}
else if (strcmp(key, "vol") == 0) {
if (!want_arg(&value, "vol"))
return -EINVAL;
*devname = value;
continue;
}
else if (strcmp(key, "cell") == 0) {
if (!want_arg(&value, "cell"))
return -EINVAL;
afs_put_cell(params->default_cell);
ret = afs_cell_lookup(value,
strlen(value),
&params->default_cell);
if (ret < 0)
return -EINVAL;
continue;
}
printk("kAFS: Unknown mount option: '%s'\n", key);
ret = -EINVAL;
goto error;
}
ret = 0;
error:
_leave(" = %d", ret);
return ret;
} /* end afs_super_parse_options() */
/*****************************************************************************/
/*
* 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_mount_params *params = data;
struct afs_super_info *as = sb->s_fs_info;
return as->volume == params->volume;
} /* end afs_test_super() */
/*****************************************************************************/
/*
* fill in the superblock
*/
static int afs_fill_super(struct super_block *sb, void *data, int silent)
{
struct afs_mount_params *params = data;
struct afs_super_info *as = NULL;
struct afs_fid fid;
struct dentry *root = NULL;
struct inode *inode = NULL;
int ret;
kenter("");
/* allocate a superblock info record */
as = kmalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (!as) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
memset(as, 0, sizeof(struct afs_super_info));
afs_get_volume(params->volume);
as->volume = params->volume;
/* 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_fs_info = as;
/* allocate the root inode and dentry */
fid.vid = as->volume->vid;
fid.vnode = 1;
fid.unique = 1;
ret = afs_iget(sb, &fid, &inode);
if (ret < 0)
goto error;
ret = -ENOMEM;
root = d_alloc_root(inode);
if (!root)
goto error;
sb->s_root = root;
kleave(" = 0");
return 0;
error:
iput(inode);
afs_put_volume(as->volume);
kfree(as);
sb->s_fs_info = NULL;
kleave(" = %d", ret);
return ret;
} /* end afs_fill_super() */
/*****************************************************************************/
/*
* get an AFS superblock
* - TODO: don't use get_sb_nodev(), but rather call sget() directly
*/
static struct super_block *afs_get_sb(struct file_system_type *fs_type,
int flags,
const char *dev_name,
void *options)
{
struct afs_mount_params params;
struct super_block *sb;
int ret;
_enter(",,%s,%p", dev_name, options);
memset(&params, 0, sizeof(params));
/* start the cache manager */
ret = afscm_start();
if (ret < 0) {
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/* parse the options */
if (options) {
ret = afs_super_parse_options(&params, options, &dev_name);
if (ret < 0)
goto error;
if (!dev_name) {
printk("kAFS: no volume name specified\n");
ret = -EINVAL;
goto error;
}
}
/* parse the device name */
ret = afs_volume_lookup(dev_name,
params.default_cell,
params.rwpath,
&params.volume);
if (ret < 0)
goto error;
/* allocate a deviceless superblock */
sb = sget(fs_type, afs_test_super, set_anon_super, &params);
if (IS_ERR(sb))
goto error;
sb->s_flags = flags;
ret = afs_fill_super(sb, &params, flags & MS_VERBOSE ? 1 : 0);
if (ret < 0) {
up_write(&sb->s_umount);
deactivate_super(sb);
goto error;
}
sb->s_flags |= MS_ACTIVE;
afs_put_volume(params.volume);
afs_put_cell(params.default_cell);
_leave(" = %p", sb);
return sb;
error:
afs_put_volume(params.volume);
afs_put_cell(params.default_cell);
afscm_stop();
_leave(" = %d", ret);
return ERR_PTR(ret);
} /* end afs_get_sb() */
/*****************************************************************************/
/*
* finish the unmounting process on the superblock
*/
static void afs_put_super(struct super_block *sb)
{
struct afs_super_info *as = sb->s_fs_info;
_enter("");
afs_put_volume(as->volume);
afscm_stop();
_leave("");
} /* end afs_put_super() */
/*****************************************************************************/
/*
* initialise an inode cache slab element prior to any use
*/
static void afs_i_init_once(void *_vnode, kmem_cache_t *cachep,
unsigned long flags)
{
struct afs_vnode *vnode = (struct afs_vnode *) _vnode;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
memset(vnode, 0, sizeof(*vnode));
inode_init_once(&vnode->vfs_inode);
init_waitqueue_head(&vnode->update_waitq);
spin_lock_init(&vnode->lock);
INIT_LIST_HEAD(&vnode->cb_link);
INIT_LIST_HEAD(&vnode->cb_hash_link);
afs_timer_init(&vnode->cb_timeout,
&afs_vnode_cb_timed_out_ops);
}
} /* end afs_i_init_once() */
/*****************************************************************************/
/*
* allocate an AFS inode struct from our slab cache
*/
static struct inode *afs_alloc_inode(struct super_block *sb)
{
struct afs_vnode *vnode;
vnode = (struct afs_vnode *)
kmem_cache_alloc(afs_inode_cachep, SLAB_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 = 0;
return &vnode->vfs_inode;
} /* end afs_alloc_inode() */
/*****************************************************************************/
/*
* destroy an AFS inode struct
*/
static void afs_destroy_inode(struct inode *inode)
{
_enter("{%lu}", inode->i_ino);
kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
atomic_dec(&afs_count_active_inodes);
} /* end afs_destroy_inode() */