/*
 *  linux/fs/hfs/super.c
 *
 * Copyright (C) 1995-1997  Paul H. Hargrove
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 * This file may be distributed under the terms of the GNU General Public License.
 *
 * This file contains hfs_read_super(), some of the super_ops and
 * init_hfs_fs() and exit_hfs_fs().  The remaining super_ops are in
 * inode.c since they deal with inodes.
 *
 * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
 */

#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/nls.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/vfs.h>

#include "hfs_fs.h"
#include "btree.h"

static struct kmem_cache *hfs_inode_cachep;

MODULE_LICENSE("GPL");

/*
 * hfs_write_super()
 *
 * Description:
 *   This function is called by the VFS only. When the filesystem
 *   is mounted r/w it updates the MDB on disk.
 * Input Variable(s):
 *   struct super_block *sb: Pointer to the hfs superblock
 * Output Variable(s):
 *   NONE
 * Returns:
 *   void
 * Preconditions:
 *   'sb' points to a "valid" (struct super_block).
 * Postconditions:
 *   The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb
 *   (hfs_put_super() must set this flag!). Some MDB fields are updated
 *   and the MDB buffer is written to disk by calling hfs_mdb_commit().
 */
static void hfs_write_super(struct super_block *sb)
{
        lock_super(sb);
        sb->s_dirt = 0;

        /* sync everything to the buffers */
        if (!(sb->s_flags & MS_RDONLY))
                hfs_mdb_commit(sb);
        unlock_super(sb);
}

static int hfs_sync_fs(struct super_block *sb, int wait)
{
        lock_super(sb);
        hfs_mdb_commit(sb);
        sb->s_dirt = 0;
        unlock_super(sb);

        return 0;
}

/*
 * hfs_put_super()
 *
 * This is the put_super() entry in the super_operations structure for
 * HFS filesystems.  The purpose is to release the resources
 * associated with the superblock sb.
 */
static void hfs_put_super(struct super_block *sb)
{
        if (sb->s_dirt)
                hfs_write_super(sb);
        hfs_mdb_close(sb);
        /* release the MDB's resources */
        hfs_mdb_put(sb);
}

/*
 * hfs_statfs()
 *
 * This is the statfs() entry in the super_operations structure for
 * HFS filesystems.  The purpose is to return various data about the
 * filesystem.
 *
 * changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
 */
static int hfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

        buf->f_type = HFS_SUPER_MAGIC;
        buf->f_bsize = sb->s_blocksize;
        buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
        buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
        buf->f_bavail = buf->f_bfree;
        buf->f_files = HFS_SB(sb)->fs_ablocks;
        buf->f_ffree = HFS_SB(sb)->free_ablocks;
        buf->f_fsid.val[0] = (u32)id;
        buf->f_fsid.val[1] = (u32)(id >> 32);
        buf->f_namelen = HFS_NAMELEN;

        return 0;
}

static int hfs_remount(struct super_block *sb, int *flags, char *data)
{
        *flags |= MS_NODIRATIME;
        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
                return 0;
        if (!(*flags & MS_RDONLY)) {
                if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
                        printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
                               "running fsck.hfs is recommended.  leaving read-only.\n");
                        sb->s_flags |= MS_RDONLY;
                        *flags |= MS_RDONLY;
                } else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
                        printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
                        sb->s_flags |= MS_RDONLY;
                        *flags |= MS_RDONLY;
                }
        }
        return 0;
}

static int hfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
{
        struct hfs_sb_info *sbi = HFS_SB(mnt->mnt_sb);

        if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
                seq_printf(seq, ",creator=%.4s", (char *)&sbi->s_creator);
        if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
                seq_printf(seq, ",type=%.4s", (char *)&sbi->s_type);
        seq_printf(seq, ",uid=%u,gid=%u", sbi->s_uid, sbi->s_gid);
        if (sbi->s_file_umask != 0133)
                seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
        if (sbi->s_dir_umask != 0022)
                seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
        if (sbi->part >= 0)
                seq_printf(seq, ",part=%u", sbi->part);
        if (sbi->session >= 0)
                seq_printf(seq, ",session=%u", sbi->session);
        if (sbi->nls_disk)
                seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
        if (sbi->nls_io)
                seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
        if (sbi->s_quiet)
                seq_printf(seq, ",quiet");
        return 0;
}

static struct inode *hfs_alloc_inode(struct super_block *sb)
{
        struct hfs_inode_info *i;

        i = kmem_cache_alloc(hfs_inode_cachep, GFP_KERNEL);
        return i ? &i->vfs_inode : NULL;
}

static void hfs_i_callback(struct rcu_head *head)
{
        struct inode *inode = container_of(head, struct inode, i_rcu);
        INIT_LIST_HEAD(&inode->i_dentry);
        kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
}

static void hfs_destroy_inode(struct inode *inode)
{
        call_rcu(&inode->i_rcu, hfs_i_callback);
}

static const struct super_operations hfs_super_operations = {
        .alloc_inode    = hfs_alloc_inode,
        .destroy_inode  = hfs_destroy_inode,
        .write_inode    = hfs_write_inode,
        .evict_inode    = hfs_evict_inode,
        .put_super      = hfs_put_super,
        .write_super    = hfs_write_super,
        .sync_fs        = hfs_sync_fs,
        .statfs         = hfs_statfs,
        .remount_fs     = hfs_remount,
        .show_options   = hfs_show_options,
};

enum {
        opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
        opt_part, opt_session, opt_type, opt_creator, opt_quiet,
        opt_codepage, opt_iocharset,
        opt_err
};

static const match_table_t tokens = {
        { opt_uid, "uid=%u" },
        { opt_gid, "gid=%u" },
        { opt_umask, "umask=%o" },
        { opt_file_umask, "file_umask=%o" },
        { opt_dir_umask, "dir_umask=%o" },
        { opt_part, "part=%u" },
        { opt_session, "session=%u" },
        { opt_type, "type=%s" },
        { opt_creator, "creator=%s" },
        { opt_quiet, "quiet" },
        { opt_codepage, "codepage=%s" },
        { opt_iocharset, "iocharset=%s" },
        { opt_err, NULL }
};

static inline int match_fourchar(substring_t *arg, u32 *result)
{
        if (arg->to - arg->from != 4)
                return -EINVAL;
        memcpy(result, arg->from, 4);
        return 0;
}

/*
 * parse_options()
 *
 * adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
 * This function is called by hfs_read_super() to parse the mount options.
 */
static int parse_options(char *options, struct hfs_sb_info *hsb)
{
        char *p;
        substring_t args[MAX_OPT_ARGS];
        int tmp, token;

        /* initialize the sb with defaults */
        hsb->s_uid = current_uid();
        hsb->s_gid = current_gid();
        hsb->s_file_umask = 0133;
        hsb->s_dir_umask = 0022;
        hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
        hsb->s_quiet = 0;
        hsb->part = -1;
        hsb->session = -1;

        if (!options)
                return 1;

        while ((p = strsep(&options, ",")) != NULL) {
                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case opt_uid:
                        if (match_int(&args[0], &tmp)) {
                                printk(KERN_ERR "hfs: uid requires an argument\n");
                                return 0;
                        }
                        hsb->s_uid = (uid_t)tmp;
                        break;
                case opt_gid:
                        if (match_int(&args[0], &tmp)) {
                                printk(KERN_ERR "hfs: gid requires an argument\n");
                                return 0;
                        }
                        hsb->s_gid = (gid_t)tmp;
                        break;
                case opt_umask:
                        if (match_octal(&args[0], &tmp)) {
                                printk(KERN_ERR "hfs: umask requires a value\n");
                                return 0;
                        }
                        hsb->s_file_umask = (umode_t)tmp;
                        hsb->s_dir_umask = (umode_t)tmp;
                        break;
                case opt_file_umask:
                        if (match_octal(&args[0], &tmp)) {
                                printk(KERN_ERR "hfs: file_umask requires a value\n");
                                return 0;
                        }
                        hsb->s_file_umask = (umode_t)tmp;
                        break;
                case opt_dir_umask:
                        if (match_octal(&args[0], &tmp)) {
                                printk(KERN_ERR "hfs: dir_umask requires a value\n");
                                return 0;
                        }
                        hsb->s_dir_umask = (umode_t)tmp;
                        break;
                case opt_part:
                        if (match_int(&args[0], &hsb->part)) {
                                printk(KERN_ERR "hfs: part requires an argument\n");
                                return 0;
                        }
                        break;
                case opt_session:
                        if (match_int(&args[0], &hsb->session)) {
                                printk(KERN_ERR "hfs: session requires an argument\n");
                                return 0;
                        }
                        break;
                case opt_type:
                        if (match_fourchar(&args[0], &hsb->s_type)) {
                                printk(KERN_ERR "hfs: type requires a 4 character value\n");
                                return 0;
                        }
                        break;
                case opt_creator:
                        if (match_fourchar(&args[0], &hsb->s_creator)) {
                                printk(KERN_ERR "hfs: creator requires a 4 character value\n");
                                return 0;
                        }
                        break;
                case opt_quiet:
                        hsb->s_quiet = 1;
                        break;
                case opt_codepage:
                        if (hsb->nls_disk) {
                                printk(KERN_ERR "hfs: unable to change codepage\n");
                                return 0;
                        }
                        p = match_strdup(&args[0]);
                        if (p)
                                hsb->nls_disk = load_nls(p);
                        if (!hsb->nls_disk) {
                                printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
                                kfree(p);
                                return 0;
                        }
                        kfree(p);
                        break;
                case opt_iocharset:
                        if (hsb->nls_io) {
                                printk(KERN_ERR "hfs: unable to change iocharset\n");
                                return 0;
                        }
                        p = match_strdup(&args[0]);
                        if (p)
                                hsb->nls_io = load_nls(p);
                        if (!hsb->nls_io) {
                                printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
                                kfree(p);
                                return 0;
                        }
                        kfree(p);
                        break;
                default:
                        return 0;
                }
        }

        if (hsb->nls_disk && !hsb->nls_io) {
                hsb->nls_io = load_nls_default();
                if (!hsb->nls_io) {
                        printk(KERN_ERR "hfs: unable to load default iocharset\n");
                        return 0;
                }
        }
        hsb->s_dir_umask &= 0777;
        hsb->s_file_umask &= 0577;

        return 1;
}

/*
 * hfs_read_super()
 *
 * This is the function that is responsible for mounting an HFS
 * filesystem.  It performs all the tasks necessary to get enough data
 * from the disk to read the root inode.  This includes parsing the
 * mount options, dealing with Macintosh partitions, reading the
 * superblock and the allocation bitmap blocks, calling
 * hfs_btree_init() to get the necessary data about the extents and
 * catalog B-trees and, finally, reading the root inode into memory.
 */
static int hfs_fill_super(struct super_block *sb, void *data, int silent)
{
        struct hfs_sb_info *sbi;
        struct hfs_find_data fd;
        hfs_cat_rec rec;
        struct inode *root_inode;
        int res;

        sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
        if (!sbi)
                return -ENOMEM;

        sb->s_fs_info = sbi;

        res = -EINVAL;
        if (!parse_options((char *)data, sbi)) {
                printk(KERN_ERR "hfs: unable to parse mount options.\n");
                goto bail;
        }

        sb->s_op = &hfs_super_operations;
        sb->s_flags |= MS_NODIRATIME;
        mutex_init(&sbi->bitmap_lock);

        res = hfs_mdb_get(sb);
        if (res) {
                if (!silent)
                        printk(KERN_WARNING "hfs: can't find a HFS filesystem on dev %s.\n",
                                hfs_mdb_name(sb));
                res = -EINVAL;
                goto bail;
        }

        /* try to get the root inode */
        hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
        res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
        if (!res) {
                if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
                        res =  -EIO;
                        goto bail;
                }
                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
        }
        if (res) {
                hfs_find_exit(&fd);
                goto bail_no_root;
        }
        res = -EINVAL;
        root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
        hfs_find_exit(&fd);
        if (!root_inode)
                goto bail_no_root;

        sb->s_d_op = &hfs_dentry_operations;
        res = -ENOMEM;
        sb->s_root = d_alloc_root(root_inode);
        if (!sb->s_root)
                goto bail_iput;

        /* everything's okay */
        return 0;

bail_iput:
        iput(root_inode);
bail_no_root:
        printk(KERN_ERR "hfs: get root inode failed.\n");
bail:
        hfs_mdb_put(sb);
        return res;
}

static struct dentry *hfs_mount(struct file_system_type *fs_type,
                      int flags, const char *dev_name, void *data)
{
        return mount_bdev(fs_type, flags, dev_name, data, hfs_fill_super);
}

static struct file_system_type hfs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "hfs",
        .mount          = hfs_mount,
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
};

static void hfs_init_once(void *p)
{
        struct hfs_inode_info *i = p;

        inode_init_once(&i->vfs_inode);
}

static int __init init_hfs_fs(void)
{
        int err;

        hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
                sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
                hfs_init_once);
        if (!hfs_inode_cachep)
                return -ENOMEM;
        err = register_filesystem(&hfs_fs_type);
        if (err)
                kmem_cache_destroy(hfs_inode_cachep);
        return err;
}

static void __exit exit_hfs_fs(void)
{
        unregister_filesystem(&hfs_fs_type);
        kmem_cache_destroy(hfs_inode_cachep);
}

module_init(init_hfs_fs)
module_exit(exit_hfs_fs)