omfs: add inode routines

/*

 * Optimized MPEG FS - inode and super operations.

 * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>

 * Released under GPL v2.

 */

#include <linux/version.h>

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/fs.h>

#include <linux/vfs.h>

#include <linux/parser.h>

#include <linux/buffer_head.h>

#include <linux/vmalloc.h>

#include <linux/crc-itu-t.h>

#include "omfs.h"

MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");

MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");

MODULE_LICENSE("GPL");

struct inode *omfs_new_inode(struct inode *dir, int mode)

{

	struct inode *inode;

	u64 new_block;

	int err;

	int len;

	struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);

	inode = new_inode(dir->i_sb);

	if (!inode)

		return ERR_PTR(-ENOMEM);

	err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,

			&new_block, &len);

	if (err)

		goto fail;

	inode->i_ino = new_block;

	inode->i_mode = mode;

	inode->i_uid = current->fsuid;

	inode->i_gid = current->fsgid;

	inode->i_blocks = 0;

	inode->i_mapping->a_ops = &omfs_aops;

	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;

	switch (mode & S_IFMT) {

	case S_IFDIR:

		inode->i_op = &omfs_dir_inops;

		inode->i_fop = &omfs_dir_operations;

		inode->i_size = sbi->s_sys_blocksize;

		inc_nlink(inode);

		break;

	case S_IFREG:

		inode->i_op = &omfs_file_inops;

		inode->i_fop = &omfs_file_operations;

		inode->i_size = 0;

		break;

	}

	insert_inode_hash(inode);

	mark_inode_dirty(inode);

	return inode;

fail:

	make_bad_inode(inode);

	iput(inode);

	return ERR_PTR(err);

}

/*

 * Update the header checksums for a dirty inode based on its contents.

 * Caller is expected to hold the buffer head underlying oi and mark it

 * dirty.

 */

static void omfs_update_checksums(struct omfs_inode *oi)

{

	int xor, i, ofs = 0, count;

	u16 crc = 0;

	unsigned char *ptr = (unsigned char *) oi;

	count = be32_to_cpu(oi->i_head.h_body_size);

	ofs = sizeof(struct omfs_header);

	crc = crc_itu_t(crc, ptr + ofs, count);

	oi->i_head.h_crc = cpu_to_be16(crc);

	xor = ptr[0];

	for (i = 1; i < OMFS_XOR_COUNT; i++)

		xor ^= ptr[i];

	oi->i_head.h_check_xor = xor;

}

static int omfs_write_inode(struct inode *inode, int wait)

{

	struct omfs_inode *oi;

	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);

	struct buffer_head *bh, *bh2;

	unsigned int block;

	u64 ctime;

	int i;

	int ret = -EIO;

	int sync_failed = 0;

	/* get current inode since we may have written sibling ptrs etc. */

	block = clus_to_blk(sbi, inode->i_ino);

	bh = sb_bread(inode->i_sb, block);

	if (!bh)

		goto out;

	oi = (struct omfs_inode *) bh->b_data;

	oi->i_head.h_self = cpu_to_be64(inode->i_ino);

	if (S_ISDIR(inode->i_mode))

		oi->i_type = OMFS_DIR;

	else if (S_ISREG(inode->i_mode))

		oi->i_type = OMFS_FILE;

	else {

		printk(KERN_WARNING "omfs: unknown file type: %d\n",

			inode->i_mode);

		goto out_brelse;

	}

	oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -

		sizeof(struct omfs_header));

	oi->i_head.h_version = 1;

	oi->i_head.h_type = OMFS_INODE_NORMAL;

	oi->i_head.h_magic = OMFS_IMAGIC;

	oi->i_size = cpu_to_be64(inode->i_size);

	ctime = inode->i_ctime.tv_sec * 1000LL +

		((inode->i_ctime.tv_nsec + 999)/1000);

	oi->i_ctime = cpu_to_be64(ctime);

	omfs_update_checksums(oi);

	mark_buffer_dirty(bh);

	if (wait) {

		sync_dirty_buffer(bh);

		if (buffer_req(bh) && !buffer_uptodate(bh))

			sync_failed = 1;

	}

	/* if mirroring writes, copy to next fsblock */

	for (i = 1; i < sbi->s_mirrors; i++) {

		bh2 = sb_bread(inode->i_sb, block + i *

			(sbi->s_blocksize / sbi->s_sys_blocksize));

		if (!bh2)

			goto out_brelse;

		memcpy(bh2->b_data, bh->b_data, bh->b_size);

		mark_buffer_dirty(bh2);

		if (wait) {

			sync_dirty_buffer(bh2);

			if (buffer_req(bh2) && !buffer_uptodate(bh2))

				sync_failed = 1;

		}

		brelse(bh2);

	}

	ret = (sync_failed) ? -EIO : 0;

out_brelse:

	brelse(bh);

out:

	return ret;

}

int omfs_sync_inode(struct inode *inode)

{

	return omfs_write_inode(inode, 1);

}

/*

 * called when an entry is deleted, need to clear the bits in the

 * bitmaps.

 */

static void omfs_delete_inode(struct inode *inode)

{

	truncate_inode_pages(&inode->i_data, 0);

	if (S_ISREG(inode->i_mode)) {

		inode->i_size = 0;

		omfs_shrink_inode(inode);

	}

	omfs_clear_range(inode->i_sb, inode->i_ino, 2);

	clear_inode(inode);

}

struct inode *omfs_iget(struct super_block *sb, ino_t ino)

{

	struct omfs_sb_info *sbi = OMFS_SB(sb);

	struct omfs_inode *oi;

	struct buffer_head *bh;

	unsigned int block;

	u64 ctime;

	unsigned long nsecs;

	struct inode *inode;

	inode = iget_locked(sb, ino);

	if (!inode)

		return ERR_PTR(-ENOMEM);

	if (!(inode->i_state & I_NEW))

		return inode;

	block = clus_to_blk(sbi, ino);

	bh = sb_bread(inode->i_sb, block);

	if (!bh)

		goto iget_failed;

	oi = (struct omfs_inode *)bh->b_data;

	/* check self */

	if (ino != be64_to_cpu(oi->i_head.h_self))

		goto fail_bh;

	inode->i_uid = sbi->s_uid;

	inode->i_gid = sbi->s_gid;

	ctime = be64_to_cpu(oi->i_ctime);

	nsecs = do_div(ctime, 1000) * 1000L;

	inode->i_atime.tv_sec = ctime;

	inode->i_mtime.tv_sec = ctime;

	inode->i_ctime.tv_sec = ctime;

	inode->i_atime.tv_nsec = nsecs;

	inode->i_mtime.tv_nsec = nsecs;

	inode->i_ctime.tv_nsec = nsecs;

	inode->i_mapping->a_ops = &omfs_aops;

	switch (oi->i_type) {

	case OMFS_DIR:

		inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);

		inode->i_op = &omfs_dir_inops;

		inode->i_fop = &omfs_dir_operations;

		inode->i_size = be32_to_cpu(oi->i_head.h_body_size) +

			sizeof(struct omfs_header);

		inc_nlink(inode);

		break;

	case OMFS_FILE:

		inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);

		inode->i_fop = &omfs_file_operations;

		inode->i_size = be64_to_cpu(oi->i_size);

		break;

	}

	brelse(bh);

	unlock_new_inode(inode);

	return inode;

fail_bh:

	brelse(bh);

iget_failed:

	iget_failed(inode);

	return ERR_PTR(-EIO);

}

static void omfs_put_super(struct super_block *sb)

{

	struct omfs_sb_info *sbi = OMFS_SB(sb);

	kfree(sbi->s_imap);

	kfree(sbi);

	sb->s_fs_info = NULL;

}

static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)

{

	struct super_block *s = dentry->d_sb;

	struct omfs_sb_info *sbi = OMFS_SB(s);

	buf->f_type = OMFS_MAGIC;

	buf->f_bsize = sbi->s_blocksize;

	buf->f_blocks = sbi->s_num_blocks;

	buf->f_files = sbi->s_num_blocks;

	buf->f_namelen = OMFS_NAMELEN;

	buf->f_bfree = buf->f_bavail = buf->f_ffree =

		omfs_count_free(s);

	return 0;

}

static struct super_operations omfs_sops = {

	.write_inode	= omfs_write_inode,

	.delete_inode	= omfs_delete_inode,

	.put_super	= omfs_put_super,

	.statfs		= omfs_statfs,

	.show_options	= generic_show_options,

};

/*

 * For Rio Karma, there is an on-disk free bitmap whose location is

 * stored in the root block.  For ReplayTV, there is no such free bitmap

 * so we have to walk the tree.  Both inodes and file data are allocated

 * from the same map.  This array can be big (300k) so we allocate

 * in units of the blocksize.

 */

static int omfs_get_imap(struct super_block *sb)

{

	int bitmap_size;

	int array_size;

	int count;

	struct omfs_sb_info *sbi = OMFS_SB(sb);

	struct buffer_head *bh;

	unsigned long **ptr;

	sector_t block;

	bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);

	array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);

	if (sbi->s_bitmap_ino == ~0ULL)

		goto out;

	sbi->s_imap_size = array_size;

	sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL);

	if (!sbi->s_imap)

		goto nomem;

	block = clus_to_blk(sbi, sbi->s_bitmap_ino);

	ptr = sbi->s_imap;

	for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {

		bh = sb_bread(sb, block++);

		if (!bh)

			goto nomem_free;

		*ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);

		if (!*ptr) {

			brelse(bh);

			goto nomem_free;

		}

		memcpy(*ptr, bh->b_data, sb->s_blocksize);

		if (count < sb->s_blocksize)

			memset((void *)*ptr + count, 0xff,

				sb->s_blocksize - count);

		brelse(bh);

		ptr++;

	}

out:

	return 0;

nomem_free:

	for (count = 0; count < array_size; count++)

		kfree(sbi->s_imap[count]);

	kfree(sbi->s_imap);

nomem:

	sbi->s_imap = NULL;

	sbi->s_imap_size = 0;

	return -ENOMEM;

}

enum {

	Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask

};

static match_table_t tokens = {

	{Opt_uid, "uid=%u"},

	{Opt_gid, "gid=%u"},

	{Opt_umask, "umask=%o"},

	{Opt_dmask, "dmask=%o"},

	{Opt_fmask, "fmask=%o"},

};

static int parse_options(char *options, struct omfs_sb_info *sbi)

{

	char *p;

	substring_t args[MAX_OPT_ARGS];

	int option;

	if (!options)

		return 1;

	while ((p = strsep(&options, ",")) != NULL) {

		int token;

		if (!*p)

			continue;

		token = match_token(p, tokens, args);

		switch (token) {

		case Opt_uid:

			if (match_int(&args[0], &option))

				return 0;

			sbi->s_uid = option;

			break;

		case Opt_gid:

			if (match_int(&args[0], &option))

				return 0;

			sbi->s_gid = option;

			break;

		case Opt_umask:

			if (match_octal(&args[0], &option))

				return 0;

			sbi->s_fmask = sbi->s_dmask = option;

			break;

		case Opt_dmask:

			if (match_octal(&args[0], &option))

				return 0;

			sbi->s_dmask = option;

			break;

		case Opt_fmask:

			if (match_octal(&args[0], &option))

				return 0;

			sbi->s_fmask = option;

			break;

		default:

			return 0;

		}

	}

	return 1;

}

static int omfs_fill_super(struct super_block *sb, void *data, int silent)

{

	struct buffer_head *bh, *bh2;

	struct omfs_super_block *omfs_sb;

	struct omfs_root_block *omfs_rb;

	struct omfs_sb_info *sbi;

	struct inode *root;

	sector_t start;

	int ret = -EINVAL;

	save_mount_options(sb, (char *) data);

	sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);

	if (!sbi)

		return -ENOMEM;

	sb->s_fs_info = sbi;

	sbi->s_uid = current->uid;

	sbi->s_gid = current->gid;

	sbi->s_dmask = sbi->s_fmask = current->fs->umask;

	if (!parse_options((char *) data, sbi))

		goto end;

	sb->s_maxbytes = 0xffffffff;

	sb_set_blocksize(sb, 0x200);

	bh = sb_bread(sb, 0);

	if (!bh)

		goto end;

	omfs_sb = (struct omfs_super_block *)bh->b_data;

	if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {

		if (!silent)

			printk(KERN_ERR "omfs: Invalid superblock (%x)\n",

				   omfs_sb->s_magic);

		goto out_brelse_bh;

	}

	sb->s_magic = OMFS_MAGIC;

	sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);

	sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);

	sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);

	sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);

	sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);

	mutex_init(&sbi->s_bitmap_lock);

	if (sbi->s_sys_blocksize > PAGE_SIZE) {

		printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",

			sbi->s_sys_blocksize);

		goto out_brelse_bh;

	}

	if (sbi->s_blocksize < sbi->s_sys_blocksize ||

	    sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {

		printk(KERN_ERR "omfs: block size (%d) is out of range\n",

			sbi->s_blocksize);

		goto out_brelse_bh;

	}

	/*

	 * Use sys_blocksize as the fs block since it is smaller than a

	 * page while the fs blocksize can be larger.

	 */

	sb_set_blocksize(sb, sbi->s_sys_blocksize);

	/*

	 * ...and the difference goes into a shift.  sys_blocksize is always

	 * a power of two factor of blocksize.

	 */

	sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -

		get_bitmask_order(sbi->s_sys_blocksize);

	start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block));

	bh2 = sb_bread(sb, start);

	if (!bh2)

		goto out_brelse_bh;

	omfs_rb = (struct omfs_root_block *)bh2->b_data;

	sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);

	sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);

	if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {

		printk(KERN_ERR "omfs: block count discrepancy between "

			"super and root blocks (%llx, %llx)\n",

			sbi->s_num_blocks, be64_to_cpu(omfs_rb->r_num_blocks));

		goto out_brelse_bh2;

	}

	ret = omfs_get_imap(sb);

	if (ret)

		goto out_brelse_bh2;

	sb->s_op = &omfs_sops;

	root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));

	if (IS_ERR(root)) {

		ret = PTR_ERR(root);

		goto out_brelse_bh2;

	}

	sb->s_root = d_alloc_root(root);

	if (!sb->s_root) {

		iput(root);

		goto out_brelse_bh2;

	}

	printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);

	ret = 0;

out_brelse_bh2:

	brelse(bh2);

out_brelse_bh:

	brelse(bh);

end:

	return ret;

}

static int omfs_get_sb(struct file_system_type *fs_type,

			int flags, const char *dev_name,

			void *data, struct vfsmount *m)

{

	return get_sb_bdev(fs_type, flags, dev_name, data, omfs_fill_super, m);

}

static struct file_system_type omfs_fs_type = {

	.owner = THIS_MODULE,

	.name = "omfs",

	.get_sb = omfs_get_sb,

	.kill_sb = kill_block_super,

	.fs_flags = FS_REQUIRES_DEV,

};

static int __init init_omfs_fs(void)

{

	return register_filesystem(&omfs_fs_type);

}

static void __exit exit_omfs_fs(void)

{

	unregister_filesystem(&omfs_fs_type);

}

module_init(init_omfs_fs);

module_exit(exit_omfs_fs);