- 根目录:
- fs
- jffs2
- super.c
/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/mount.h>
#include <linux/parser.h>
#include <linux/jffs2.h>
#include <linux/pagemap.h>
#include <linux/mtd/super.h>
#include <linux/ctype.h>
#include <linux/namei.h>
#include <linux/seq_file.h>
#include <linux/exportfs.h>
#include "compr.h"
#include "nodelist.h"
static void jffs2_put_super(struct super_block *);
static struct kmem_cache *jffs2_inode_cachep;
static struct inode *jffs2_alloc_inode(struct super_block *sb)
{
struct jffs2_inode_info *f;
f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
if (!f)
return NULL;
return &f->vfs_inode;
}
static void jffs2_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
}
static void jffs2_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, jffs2_i_callback);
}
static void jffs2_i_init_once(void *foo)
{
struct jffs2_inode_info *f = foo;
mutex_init(&f->sem);
inode_init_once(&f->vfs_inode);
}
static const char *jffs2_compr_name(unsigned int compr)
{
switch (compr) {
case JFFS2_COMPR_MODE_NONE:
return "none";
#ifdef CONFIG_JFFS2_LZO
case JFFS2_COMPR_MODE_FORCELZO:
return "lzo";
#endif
#ifdef CONFIG_JFFS2_ZLIB
case JFFS2_COMPR_MODE_FORCEZLIB:
return "zlib";
#endif
default:
/* should never happen; programmer error */
WARN_ON(1);
return "";
}
}
static int jffs2_show_options(struct seq_file *s, struct dentry *root)
{
struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
struct jffs2_mount_opts *opts = &c->mount_opts;
if (opts->override_compr)
seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
if (opts->rp_size)
seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
return 0;
}
static int jffs2_sync_fs(struct super_block *sb, int wait)
{
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
cancel_delayed_work_sync(&c->wbuf_dwork);
#endif
mutex_lock(&c->alloc_sem);
jffs2_flush_wbuf_pad(c);
mutex_unlock(&c->alloc_sem);
return 0;
}
static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
uint32_t generation)
{
/* We don't care about i_generation. We'll destroy the flash
before we start re-using inode numbers anyway. And even
if that wasn't true, we'd have other problems...*/
return jffs2_iget(sb, ino);
}
static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
jffs2_nfs_get_inode);
}
static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
return generic_fh_to_parent(sb, fid, fh_len, fh_type,
jffs2_nfs_get_inode);
}
static struct dentry *jffs2_get_parent(struct dentry *child)
{
struct jffs2_inode_info *f;
uint32_t pino;
BUG_ON(!d_is_dir(child));
f = JFFS2_INODE_INFO(d_inode(child));
pino = f->inocache->pino_nlink;
JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
f->inocache->ino, pino);
return d_obtain_alias(jffs2_iget(d_inode(child)->i_sb, pino));
}
static const struct export_operations jffs2_export_ops = {
.get_parent = jffs2_get_parent,
.fh_to_dentry = jffs2_fh_to_dentry,
.fh_to_parent = jffs2_fh_to_parent,
};
/*
* JFFS2 mount options.
*
* Opt_override_compr: override default compressor
* Opt_rp_size: size of reserved pool in KiB
* Opt_err: just end of array marker
*/
enum {
Opt_override_compr,
Opt_rp_size,
Opt_err,
};
static const match_table_t tokens = {
{Opt_override_compr, "compr=%s"},
{Opt_rp_size, "rp_size=%u"},
{Opt_err, NULL},
};
static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
{
substring_t args[MAX_OPT_ARGS];
char *p, *name;
unsigned int opt;
if (!data)
return 0;
while ((p = strsep(&data, ","))) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_override_compr:
name = match_strdup(&args[0]);
if (!name)
return -ENOMEM;
if (!strcmp(name, "none"))
c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
#ifdef CONFIG_JFFS2_LZO
else if (!strcmp(name, "lzo"))
c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
#endif
#ifdef CONFIG_JFFS2_ZLIB
else if (!strcmp(name, "zlib"))
c->mount_opts.compr =
JFFS2_COMPR_MODE_FORCEZLIB;
#endif
else {
pr_err("Error: unknown compressor \"%s\"\n",
name);
kfree(name);
return -EINVAL;
}
kfree(name);
c->mount_opts.override_compr = true;
break;
case Opt_rp_size:
if (match_int(&args[0], &opt))
return -EINVAL;
opt *= 1024;
if (opt > c->mtd->size) {
pr_warn("Too large reserve pool specified, max "
"is %llu KB\n", c->mtd->size / 1024);
return -EINVAL;
}
c->mount_opts.rp_size = opt;
break;
default:
pr_err("Error: unrecognized mount option '%s' or missing value\n",
p);
return -EINVAL;
}
}
return 0;
}
static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
{
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
int err;
sync_filesystem(sb);
err = jffs2_parse_options(c, data);
if (err)
return -EINVAL;
return jffs2_do_remount_fs(sb, flags, data);
}
static const struct super_operations jffs2_super_operations =
{
.alloc_inode = jffs2_alloc_inode,
.destroy_inode =jffs2_destroy_inode,
.put_super = jffs2_put_super,
.statfs = jffs2_statfs,
.remount_fs = jffs2_remount_fs,
.evict_inode = jffs2_evict_inode,
.dirty_inode = jffs2_dirty_inode,
.show_options = jffs2_show_options,
.sync_fs = jffs2_sync_fs,
};
/*
* fill in the superblock
*/
static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
{
struct jffs2_sb_info *c;
int ret;
jffs2_dbg(1, "jffs2_get_sb_mtd():"
" New superblock for device %d (\"%s\")\n",
sb->s_mtd->index, sb->s_mtd->name);
c = kzalloc(sizeof(*c), GFP_KERNEL);
if (!c)
return -ENOMEM;
c->mtd = sb->s_mtd;
c->os_priv = sb;
sb->s_fs_info = c;
ret = jffs2_parse_options(c, data);
if (ret) {
kfree(c);
return -EINVAL;
}
/* Initialize JFFS2 superblock locks, the further initialization will
* be done later */
mutex_init(&c->alloc_sem);
mutex_init(&c->erase_free_sem);
init_waitqueue_head(&c->erase_wait);
init_waitqueue_head(&c->inocache_wq);
spin_lock_init(&c->erase_completion_lock);
spin_lock_init(&c->inocache_lock);
sb->s_op = &jffs2_super_operations;
sb->s_export_op = &jffs2_export_ops;
sb->s_flags = sb->s_flags | MS_NOATIME;
sb->s_xattr = jffs2_xattr_handlers;
#ifdef CONFIG_JFFS2_FS_POSIX_ACL
sb->s_flags |= MS_POSIXACL;
#endif
ret = jffs2_do_fill_super(sb, data, silent);
return ret;
}
static struct dentry *jffs2_mount(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data)
{
return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
}
static void jffs2_put_super (struct super_block *sb)
{
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
jffs2_dbg(2, "%s()\n", __func__);
mutex_lock(&c->alloc_sem);
jffs2_flush_wbuf_pad(c);
mutex_unlock(&c->alloc_sem);
jffs2_sum_exit(c);
jffs2_free_ino_caches(c);
jffs2_free_raw_node_refs(c);
if (jffs2_blocks_use_vmalloc(c))
vfree(c->blocks);
else
kfree(c->blocks);
jffs2_flash_cleanup(c);
kfree(c->inocache_list);
jffs2_clear_xattr_subsystem(c);
mtd_sync(c->mtd);
jffs2_dbg(1, "%s(): returning\n", __func__);
}
static void jffs2_kill_sb(struct super_block *sb)
{
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
if (!(sb->s_flags & MS_RDONLY))
jffs2_stop_garbage_collect_thread(c);
kill_mtd_super(sb);
kfree(c);
}
static struct file_system_type jffs2_fs_type = {
.owner = THIS_MODULE,
.name = "jffs2",
.mount = jffs2_mount,
.kill_sb = jffs2_kill_sb,
};
MODULE_ALIAS_FS("jffs2");
static int __init init_jffs2_fs(void)
{
int ret;
/* Paranoia checks for on-medium structures. If we ask GCC
to pack them with __attribute__((packed)) then it _also_
assumes that they're not aligned -- so it emits crappy
code on some architectures. Ideally we want an attribute
which means just 'no padding', without the alignment
thing. But GCC doesn't have that -- we have to just
hope the structs are the right sizes, instead. */
BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
pr_info("version 2.2."
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
" (NAND)"
#endif
#ifdef CONFIG_JFFS2_SUMMARY
" (SUMMARY) "
#endif
" © 2001-2006 Red Hat, Inc.\n");
jffs2_inode_cachep = kmem_cache_create("jffs2_i",
sizeof(struct jffs2_inode_info),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
jffs2_i_init_once);
if (!jffs2_inode_cachep) {
pr_err("error: Failed to initialise inode cache\n");
return -ENOMEM;
}
ret = jffs2_compressors_init();
if (ret) {
pr_err("error: Failed to initialise compressors\n");
goto out;
}
ret = jffs2_create_slab_caches();
if (ret) {
pr_err("error: Failed to initialise slab caches\n");
goto out_compressors;
}
ret = register_filesystem(&jffs2_fs_type);
if (ret) {
pr_err("error: Failed to register filesystem\n");
goto out_slab;
}
return 0;
out_slab:
jffs2_destroy_slab_caches();
out_compressors:
jffs2_compressors_exit();
out:
kmem_cache_destroy(jffs2_inode_cachep);
return ret;
}
static void __exit exit_jffs2_fs(void)
{
unregister_filesystem(&jffs2_fs_type);
jffs2_destroy_slab_caches();
jffs2_compressors_exit();
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(jffs2_inode_cachep);
}
module_init(init_jffs2_fs);
module_exit(exit_jffs2_fs);
MODULE_DESCRIPTION("The Journalling Flash File System, v2");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
// the sake of this tag. It's Free Software.