linux/fs/afs/super.c

522 lines
11 KiB
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@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 "internal.h"
#define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
static void afs_i_init_once(void *foo, struct kmem_cache *cachep,
unsigned long flags);
static int afs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, struct vfsmount *mnt);
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);
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 const 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,
.umount_begin = afs_umount_begin,
.put_super = afs_put_super,
};
static struct kmem_cache *afs_inode_cachep;
static atomic_t afs_count_active_inodes;
/*
* 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,
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);
_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();
}
kmem_cache_destroy(afs_inode_cachep);
_leave("");
}
/*
* 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;
}
/*
* 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;
}
/*
* 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;
char *key, *value;
int ret;
_enter("%s", options);
options[PAGE_SIZE - 1] = 0;
ret = 0;
while ((key = strsep(&options, ","))) {
value = strchr(key, '=');
if (value)
*value++ = 0;
_debug("kAFS: KEY: %s, VAL:%s", key, value ?: "-");
if (strcmp(key, "rwpath") == 0) {
if (!want_no_value(&value, "rwpath"))
return -EINVAL;
params->rwpath = 1;
} else if (strcmp(key, "vol") == 0) {
if (!want_arg(&value, "vol"))
return -EINVAL;
*devname = value;
} else if (strcmp(key, "cell") == 0) {
if (!want_arg(&value, "cell"))
return -EINVAL;
cell = afs_cell_lookup(value, strlen(value));
if (IS_ERR(cell))
return PTR_ERR(cell);
afs_put_cell(params->cell);
params->cell = cell;
} else {
printk("kAFS: Unknown mount option: '%s'\n", key);
ret = -EINVAL;
goto error;
}
}
ret = 0;
error:
_leave(" = %d", ret);
return ret;
}
/*
* 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);
if (IS_ERR(cell)) {
printk(KERN_ERR "kAFS: unable to lookup cell '%s'\n",
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_mount_params *params = data;
struct afs_super_info *as = sb->s_fs_info;
return as->volume == params->volume;
}
/*
* fill in the superblock
*/
static int afs_fill_super(struct super_block *sb, void *data)
{
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;
_enter("");
/* allocate a superblock info record */
as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (!as) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
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;
inode = afs_iget(sb, params->key, &fid, NULL, NULL);
if (IS_ERR(inode))
goto error_inode;
ret = -ENOMEM;
root = d_alloc_root(inode);
if (!root)
goto error;
sb->s_root = root;
_leave(" = 0");
return 0;
error_inode:
ret = PTR_ERR(inode);
inode = NULL;
error:
iput(inode);
afs_put_volume(as->volume);
kfree(as);
sb->s_fs_info = NULL;
_leave(" = %d", ret);
return ret;
}
/*
* get an AFS superblock
* - TODO: don't use get_sb_nodev(), but rather call sget() directly
*/
static int afs_get_sb(struct file_system_type *fs_type,
int flags,
const char *dev_name,
void *options,
struct vfsmount *mnt)
{
struct afs_mount_params params;
struct super_block *sb;
struct afs_volume *vol;
struct key *key;
int ret;
_enter(",,%s,%p", dev_name, options);
memset(&params, 0, sizeof(params));
/* parse the options and device name */
if (options) {
ret = afs_parse_options(&params, options, &dev_name);
if (ret < 0)
goto error;
}
ret = afs_parse_device_name(&params, 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(&params);
if (IS_ERR(vol)) {
ret = PTR_ERR(vol);
goto error;
}
params.volume = vol;
/* allocate a deviceless superblock */
sb = sget(fs_type, afs_test_super, set_anon_super, &params);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
goto error;
}
if (!sb->s_root) {
/* initial superblock/root creation */
_debug("create");
sb->s_flags = flags;
ret = afs_fill_super(sb, &params);
if (ret < 0) {
up_write(&sb->s_umount);
deactivate_super(sb);
goto error;
}
sb->s_flags |= MS_ACTIVE;
} else {
_debug("reuse");
ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
}
simple_set_mnt(mnt, sb);
afs_put_volume(params.volume);
afs_put_cell(params.cell);
_leave(" = 0 [%p]", sb);
return 0;
error:
afs_put_volume(params.volume);
afs_put_cell(params.cell);
key_put(params.key);
_leave(" = %d", ret);
return ret;
}
/*
* 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);
_leave("");
}
/*
* initialise an inode cache slab element prior to any use
*/
static void afs_i_init_once(void *_vnode, struct kmem_cache *cachep,
unsigned long flags)
{
struct afs_vnode *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);
mutex_init(&vnode->permits_lock);
mutex_init(&vnode->validate_lock);
spin_lock_init(&vnode->lock);
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;
return &vnode->vfs_inode;
}
/*
* destroy an AFS inode struct
*/
static void afs_destroy_inode(struct inode *inode)
{
struct afs_vnode *vnode = AFS_FS_I(inode);
_enter("{%lu}", inode->i_ino);
_debug("DESTROY INODE %p", inode);
ASSERTCMP(vnode->server, ==, NULL);
kmem_cache_free(afs_inode_cachep, vnode);
atomic_dec(&afs_count_active_inodes);
}