[PATCH] VMUFAT filesystem [3/4]

[Adrian McMenamin]

diff --git a/fs/vmufat/super.c b/fs/vmufat/super.c
new file mode 100644
index 0000000..89a6e93
--- /dev/null
+++ b/fs/vmufat/super.c
@@ -0,0 +1,559 @@
+/*
+ * VMUFAT file system
+ *
+ * Copyright (C) 2002 - 2012	Adrian McMenamin
+ * Copyright (C) 2002		Paul Mundt
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/fs.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/magic.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/statfs.h>
+#include <linux/buffer_head.h>
+#include "vmufat.h"
+
+static struct kmem_cache *vmufat_inode_cachep;
+static const struct super_operations vmufat_super_operations;
+extern int *day_n;
+extern struct kmem_cache *vmufat_blist_cachep;
+extern const struct inode_operations vmufat_inode_operations;
+extern const struct file_operations vmufat_file_operations;
+extern const struct address_space_operations vmufat_address_space_operations;
+extern const struct file_operations vmufat_file_dir_operations;
+
+static long vmufat_get_date(struct buffer_head *bh, int offset)
+{
+	int century, year, month, day, hour, minute, second;
+	if (!bh)
+		return -EINVAL;
+
+	century = bcd2bin(bh->b_data[offset++]);
+	year = bcd2bin(bh->b_data[offset++]);
+	month = bcd2bin(bh->b_data[offset++]);
+	day = bcd2bin(bh->b_data[offset++]);
+	hour = bcd2bin(bh->b_data[offset++]);
+	minute = bcd2bin(bh->b_data[offset++]);
+	second = bcd2bin(bh->b_data[offset]);
+
+	return mktime(century * 100 + year, month, day, hour, minute,
+		second);
+}
+
+static struct inode *vmufat_alloc_inode(struct super_block *sb)
+{
+	struct vmufat_inode *vi = kmem_cache_alloc(vmufat_inode_cachep,
+		GFP_KERNEL);
+	if (!vi)
+		return NULL;
+
+	INIT_LIST_HEAD(&vi->blocks.b_list);
+	return &vi->vfs_inode;
+}
+
+static void vmufat_destroy_inode(struct inode *in)
+{
+	struct vmufat_inode *vi;
+	struct vmufat_block_list *vb;
+	struct list_head *iter, *iter2;
+	if (!in)
+		return;
+	vi = VMUFAT_I(in);
+	if (!vi)
+		return;
+
+	list_for_each_safe(iter, iter2, &vi->blocks.b_list) {
+		vb = list_entry(iter, struct vmufat_block_list, b_list);
+		list_del(iter);
+		kmem_cache_free(vmufat_blist_cachep, vb);
+	}
+	kmem_cache_free(vmufat_inode_cachep, vi);
+}
+
+struct inode *vmufat_get_inode(struct super_block *sb, long ino)
+{
+	struct buffer_head *bh = NULL;
+	int error = 0, i, j, found = 0;
+	int offsetindir;
+	struct inode *inode;
+	struct memcard *vmudetails;
+	long superblock_bno;
+	if (!sb || !sb->s_fs_info) {
+		error = -EINVAL;
+		goto reterror;
+	}
+
+	vmudetails = sb->s_fs_info;
+	inode = iget_locked(sb, ino);
+	if (!inode) {
+		error = -EIO;
+		goto reterror;
+	}
+	superblock_bno = vmudetails->sb_bnum;
+
+	if (inode->i_state & I_NEW) {
+		inode->i_uid = current_fsuid();
+		inode->i_gid = current_fsgid();
+		inode->i_mode &= ~S_IFMT;
+		if (inode->i_ino == superblock_bno) {
+			bh = vmufat_sb_bread(sb, inode->i_ino);
+			if (!bh) {
+				error = -EIO;
+				goto failed;
+			}
+			inode->i_ctime.tv_sec = inode->i_mtime.tv_sec =
+				vmufat_get_date(bh, VMUFAT_SB_DATEOFFSET);
+
+			/* Mark as a directory */
+			inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
+			inode->i_op = &vmufat_inode_operations;
+			inode->i_fop = &vmufat_file_dir_operations;
+		} else {
+			/* Mark file as regular type */
+			inode->i_mode = S_IFREG | S_IRUGO | S_IWUSR;
+
+			/* Scan through the directory to find matching file */
+			for (i = vmudetails->dir_bnum;
+				i > vmudetails->dir_bnum - vmudetails->dir_len;
+				i--) {
+				brelse(bh);
+				bh = vmufat_sb_bread(sb, i);
+				if (!bh) {
+					error = -EIO;
+					goto failed;
+				}
+				for (j = 0; j < VMU_DIR_ENTRIES_PER_BLOCK; j++)
+				{
+					if (bh->b_data[j * VMU_DIR_RECORD_LEN]
+						== 0)
+						goto notfound;
+					if (le16_to_cpu(((u16 *) bh->b_data)
+					[j * VMU_DIR_RECORD_LEN16 +
+					VMUFAT_FIRSTBLOCK_OFFSET16]) == ino) {
+						found = 1;
+						goto found;
+					}
+				}
+			}
+notfound:
+			error = -ENOENT;
+			goto failed;
+found:
+			/* identified the correct directory entry */
+			offsetindir = j * VMU_DIR_RECORD_LEN;
+			inode->i_ctime.tv_sec = inode->i_mtime.tv_sec =
+				vmufat_get_date(bh,
+					offsetindir + VMUFAT_FILE_DATEOFFSET);
+
+			/* Execute if a game, write if not copy protected */
+			inode->i_mode &= ~(S_IWUGO | S_IXUGO);
+			inode->i_mode |= S_IRUGO;
+
+			/* Mode - is it write protected? */
+			if ((((u8 *) bh->b_data)[0x01 + offsetindir] ==
+			     0x00) & ~(sb->s_flags & MS_RDONLY))
+				inode->i_mode |= S_IWUSR;
+			/* Is file executible - ie a game */
+			if ((((u8 *) bh->b_data)[offsetindir] ==
+			     0xcc) & ~(sb->s_flags & MS_NOEXEC))
+				inode->i_mode |= S_IXUSR;
+
+			inode->i_fop = &vmufat_file_operations;
+
+			inode->i_blocks =
+			    le16_to_cpu(((u16 *) bh->b_data)
+				[offsetindir / 2 + 0x0C]);
+			inode->i_size = inode->i_blocks * sb->s_blocksize;
+
+			inode->i_mapping->a_ops =
+				&vmufat_address_space_operations;
+			inode->i_op = &vmufat_inode_operations;
+			inode->i_fop = &vmufat_file_operations;
+			error = vmufat_list_blocks(inode);
+			if (error)
+				goto failed;
+		}
+		inode->i_atime = CURRENT_TIME;
+		unlock_new_inode(inode);
+	}
+	brelse(bh);
+	return inode;
+
+failed:
+	iget_failed(inode);
+reterror:
+	brelse(bh);
+	return ERR_PTR(error);
+}
+
+static void vmufat_put_super(struct super_block *sb)
+{
+	if (!sb)
+		return;
+	sb->s_dev = 0;
+	kfree(sb->s_fs_info);
+}
+
+static int vmufat_count_freeblocks(struct super_block *sb,
+					struct kstatfs *kstatbuf)
+{
+	int error = 0;
+	int free = 0;
+	int i;
+	struct memcard *vmudetails;
+
+	if (!sb || !sb->s_fs_info || !kstatbuf) {
+		error = -EINVAL;
+		goto out;
+	}
+	vmudetails = sb->s_fs_info;
+
+	/* Look through the FAT */
+	for (i = 0; i < vmudetails->numblocks; i++) {
+		if (vmufat_get_fat(sb, i) == VMUFAT_UNALLOCATED)
+			free++;
+	}
+	kstatbuf->f_bfree = free;
+	kstatbuf->f_bavail = free;
+	kstatbuf->f_blocks = vmudetails->numblocks;
+out:
+	return error;
+}
+
+static int vmufat_statfs(struct dentry *dentry, struct kstatfs *kstatbuf)
+{
+	int error;
+	struct super_block *sb;
+
+	if (!dentry || !kstatbuf) {
+		error = -EINVAL;
+		goto out;
+	}
+
+	sb = dentry->d_sb;
+	if (!sb) {
+		error = -EINVAL;
+		goto out;
+	}
+	error = vmufat_count_freeblocks(sb, kstatbuf);
+	if (error)
+		goto out;
+	kstatbuf->f_type = VMUFAT_MAGIC;
+	kstatbuf->f_bsize = sb->s_blocksize;
+	kstatbuf->f_namelen = VMUFAT_NAMELEN;
+out:
+	return error;
+}
+
+/* Remove inode from memory */
+static void vmufat_evict_inode(struct inode *in)
+{
+	if (!in)
+		return;
+
+	truncate_inode_pages(&in->i_data, 0);
+	invalidate_inode_buffers(in);
+	in->i_size = 0;
+	end_writeback(in);
+}
+
+/*
+ * There are no inodes on the medium - vmufat_write_inode
+ * updates the directory entry
+ */
+static int vmufat_write_inode(struct inode *in, struct writeback_control *wbc)
+{
+	struct buffer_head *bh = NULL;
+	unsigned long inode_num;
+	int i, j, found = 0;
+	struct super_block *sb;
+	struct memcard *vmudetails;
+	if (!in || !in->i_sb)
+		return -EINVAL;
+	sb = in->i_sb;
+	vmudetails = sb->s_fs_info;
+	if (!vmudetails)
+		return -EINVAL;
+
+	/* As most real world devices are flash we
+	 * won't update the superblock every time */
+	if (in->i_ino == vmudetails->sb_bnum)
+		return 0;
+	if (in->i_ino == VMUFAT_ZEROBLOCK)
+		inode_num = 0;
+	else
+		inode_num = in->i_ino;
+
+	/* update the directory and inode details */
+	/* Now search for the directory entry */
+	down_interruptible(&vmudetails->vmu_sem);
+	for (i = vmudetails->dir_bnum;
+		i > vmudetails->dir_bnum - vmudetails->dir_len; i--) {
+		bh = vmufat_sb_bread(sb, i);
+		if (!bh) {
+			up(&vmudetails->vmu_sem);
+			return -EIO;
+		}
+		for (j = 0; j < VMU_DIR_ENTRIES_PER_BLOCK; j++) {
+			if (bh->b_data[j * VMU_DIR_RECORD_LEN] == 0) {
+				up(&vmudetails->vmu_sem);
+				brelse(bh);
+				return -ENOENT;
+			}
+			if (le16_to_cpu(((u16 *)bh->b_data)
+				[j * VMU_DIR_RECORD_LEN16 +
+				VMUFAT_FIRSTBLOCK_OFFSET16]) == inode_num) {
+				found = 1;
+				goto found;
+			}
+		}
+		brelse(bh);
+	}
+found:
+	if (found == 0) {
+		up(&vmudetails->vmu_sem);
+		return -EIO;
+	}
+
+	/* Have the directory entry
+	 * so now update it */
+	if (inode_num != 0)
+		bh->b_data[j * VMU_DIR_RECORD_LEN] = VMU_DATA;	/* data file */
+	else
+		bh->b_data[j * VMU_DIR_RECORD_LEN] = VMU_GAME;
+	if (bh->b_data[j * VMU_DIR_RECORD_LEN + 1] !=  0
+	    && bh->b_data[j * VMU_DIR_RECORD_LEN + 1] != (char) 0xff)
+		bh->b_data[j * VMU_DIR_RECORD_LEN + 1] = 0;
+	((u16 *) bh->b_data)[j * VMU_DIR_RECORD_LEN16 + 1] =
+		cpu_to_le16(inode_num);
+
+	/* BCD timestamp it */
+	in->i_mtime = CURRENT_TIME;
+	vmufat_save_bcd(in, bh->b_data, j * VMU_DIR_RECORD_LEN);
+
+	((u16 *) bh->b_data)[j * VMU_DIR_RECORD_LEN16 + 0x0C] =
+		cpu_to_le16(in->i_blocks);
+	if (inode_num != 0)
+		((u16 *) bh->b_data)[j * VMU_DIR_RECORD_LEN16 + 0x0D] = 0;
+	else /* game */
+		((u16 *) bh->b_data)[j * VMU_DIR_RECORD_LEN16 + 0x0D] =
+			cpu_to_le16(1);
+	up(&vmudetails->vmu_sem);
+	mark_buffer_dirty(bh);
+	brelse(bh);
+	return 0;
+}
+
+static int check_sb_format(struct buffer_head *bh)
+{
+	if (!bh)
+		return -EINVAL;
+
+	return (((u32 *) bh->b_data)[0] == VMUFAT_MAGIC &&
+		((u32 *) bh->b_data)[1] == VMUFAT_MAGIC &&
+		((u32 *) bh->b_data)[2] == VMUFAT_MAGIC &&
+		((u32 *) bh->b_data)[3] == VMUFAT_MAGIC);
+}
+
+static void vmufat_populate_vmudata(struct memcard *vmudata,
+		struct buffer_head *bh, int test_sz)
+{
+	vmudata->sb_bnum = test_sz - 1;
+	vmudata->fat_bnum =
+		le16_to_cpu(((u16 *) bh->b_data)[VMU_LOCATION_FAT]);
+	vmudata->fat_len =
+		le16_to_cpu(((u16 *) bh->b_data)[VMU_LOCATION_FATLEN]);
+	vmudata->dir_bnum =
+		le16_to_cpu(((u16 *) bh->b_data)[VMU_LOCATION_DIR]);
+	vmudata->dir_len =
+		le16_to_cpu(((u16 *) bh->b_data)[VMU_LOCATION_DIRLEN]);
+	/* return the true number of user available blocks - VMUs
+ 	 * return a neat 200 and ignore 40 blocks of usable space -
+ 	 * we get round that in a hardware neutral way */
+	vmudata->numblocks = vmudata->dir_bnum - vmudata->dir_len + 1;
+}
+
+static int vmufat_get_size(struct super_block *sb, struct buffer_head **bh)
+{
+	int i;
+
+	for (i = VMUFAT_MIN_BLK; i <= VMUFAT_MAX_BLK; i = i * 2) {
+		brelse(*bh);
+		*bh = vmufat_sb_bread(sb, i - 1);
+		if (*bh == NULL) {
+			i = -EIO;
+			goto out;
+		}
+		if (check_sb_format(*bh))
+			break;
+	}
+	if (i > VMUFAT_MAX_BLK) {
+		brelse(*bh);
+		i = -ENOENT;
+	}
+out:
+	return i;
+}
+
+static int vmufat_fill_super(struct super_block *sb,
+					    void *data, int silent)
+{
+	struct buffer_head *bh = NULL;
+	struct memcard *vmudata;
+	int test_sz;
+	struct inode *root_i;
+	int ret = -EINVAL;
+	if (!sb)
+		goto out;
+
+	sb_set_blocksize(sb, VMU_BLK_SZ);
+	sb->s_blocksize_bits = ilog2(VMU_BLK_SZ);
+	sb->s_magic = VMUFAT_MAGIC;
+	sb->s_op = &vmufat_super_operations;
+
+	/*
+	 * Hardware VMUs are 256 blocks in size but
+	 * the specification allows for other sizes
+	 */
+	test_sz = vmufat_get_size(sb, &bh);
+	if (test_sz < VMUFAT_MIN_BLK) {
+		printk(KERN_ERR "VMUFAT: attempted to mount corrupted vmufat "
+			"or non-vmufat violume as vmufat.\n");
+		ret = test_sz;
+		goto out;
+	}
+
+	vmudata = kmalloc(sizeof(struct memcard), GFP_KERNEL);
+	if (!vmudata) {
+		ret = -ENOMEM;
+		goto freebh_out;
+	}
+	vmufat_populate_vmudata(vmudata, bh, test_sz);
+	sema_init(&vmudata->vmu_sem, 1);
+	sb->s_fs_info = vmudata;
+
+	root_i = vmufat_get_inode(sb, vmudata->sb_bnum);
+	if (!root_i) {
+		printk(KERN_ERR "VMUFAT: get root inode failed\n");
+		ret = -ENOMEM;
+		goto freevmudata_out;
+	}
+	if (IS_ERR(root_i)) {
+		printk(KERN_ERR "VMUFAT: get root"
+			" inode failed - error 0x%lX\n",
+			PTR_ERR(root_i));
+		ret = PTR_ERR(root_i);
+		goto freevmudata_out;
+	}
+
+	sb->s_root = d_alloc_root(root_i);
+
+	if (!sb->s_root) {
+		ret = -EIO;
+		goto freeroot_out;
+	}
+	return 0;
+
+freeroot_out:
+	iput(root_i);
+freevmudata_out:
+	kfree(vmudata);
+freebh_out:
+	brelse(bh);
+out:
+	return ret;
+}
+
+static void init_once(void *foo)
+{
+	struct vmufat_inode *vi = foo;
+
+	vi->nblcks = 0;
+	inode_init_once(&vi->vfs_inode);
+}
+
+static int init_inodecache(void)
+{
+	vmufat_inode_cachep = kmem_cache_create("vmufat_inode_cache",
+		sizeof(struct vmufat_inode), 0,
+			SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, init_once);
+	if (!vmufat_inode_cachep)
+		return -ENOMEM;
+
+	vmufat_blist_cachep = kmem_cache_create("vmufat_blocklist_cache",
+		sizeof(struct vmufat_block_list), 0, SLAB_MEM_SPREAD, NULL);
+	if (!vmufat_blist_cachep) {
+		kmem_cache_destroy(vmufat_inode_cachep);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	kmem_cache_destroy(vmufat_blist_cachep);
+	kmem_cache_destroy(vmufat_inode_cachep);
+}
+
+static const struct super_operations vmufat_super_operations = {
+	.alloc_inode =		vmufat_alloc_inode,
+	.destroy_inode =	vmufat_destroy_inode,
+	.write_inode =		vmufat_write_inode,
+	.evict_inode =		vmufat_evict_inode,
+	.put_super =		vmufat_put_super,
+	.statfs =		vmufat_statfs,
+};
+
+static struct dentry *vmufat_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, vmufat_fill_super);
+}
+
+static struct file_system_type vmufat_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "vmufat",
+	.mount		= vmufat_mount,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+
+static int __init init_vmufat_fs(void)
+{
+	int err;
+	err = init_inodecache();
+	if (err)
+		return err;
+	return register_filesystem(&vmufat_fs_type);
+}
+
+static void __exit exit_vmufat_fs(void)
+{
+	destroy_inodecache();
+	unregister_filesystem(&vmufat_fs_type);
+}
+
+module_init(init_vmufat_fs);
+module_exit(exit_vmufat_fs);
+
+MODULE_DESCRIPTION("Filesystem used in Sega Dreamcast VMU");
+MODULE_AUTHOR("Adrian McMenamin <adrianmcmenamin@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
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