inode.c

Linux Kernel 2.6.9 for OMAP1710

			if (opts->iocharset != fat_default_iocharset)
				kfree(opts->iocharset);
			iocharset = match_strdup(&args[0]);
			if (!iocharset)
				return -ENOMEM;
			opts->iocharset = iocharset;
			break;
		case Opt_shortname_lower:
			opts->shortname = VFAT_SFN_DISPLAY_LOWER
					| VFAT_SFN_CREATE_WIN95;
			break;
		case Opt_shortname_win95:
			opts->shortname = VFAT_SFN_DISPLAY_WIN95
					| VFAT_SFN_CREATE_WIN95;
			break;
		case Opt_shortname_winnt:
			opts->shortname = VFAT_SFN_DISPLAY_WINNT
					| VFAT_SFN_CREATE_WINNT;
			break;
		case Opt_shortname_mixed:
			opts->shortname = VFAT_SFN_DISPLAY_WINNT
					| VFAT_SFN_CREATE_WIN95;
			break;
		case Opt_utf8_no:		/* 0 or no or false */
			opts->utf8 = 0;
			break;
		case Opt_utf8_yes:		/* empty or 1 or yes or true */
			opts->utf8 = 1;
			break;
		case Opt_uni_xl_no:		/* 0 or no or false */
			opts->unicode_xlate = 0;
			break;
		case Opt_uni_xl_yes:		/* empty or 1 or yes or true */
			opts->unicode_xlate = 1;
			break;
		case Opt_nonumtail_no:		/* 0 or no or false */
			opts->numtail = 1;	/* negated option */
			break;
		case Opt_nonumtail_yes:		/* empty or 1 or yes or true */
			opts->numtail = 0;	/* negated option */
			break;

		/* obsolete mount options */
		case Opt_obsolate:
			printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
			       "not supported now\n", p);
			break;
		/* unknown option */
		default:
			printk(KERN_ERR "FAT: Unrecognized mount option \"%s\" "
			       "or missing value\n", p);
			return -EINVAL;
		}
	}
	/* UTF8 doesn't provide FAT semantics */
	if (!strcmp(opts->iocharset, "utf8")) {
		printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
		       " for FAT filesystems, filesystem will be case sensitive!\n");
	}

	if (opts->unicode_xlate)
		opts->utf8 = 0;
	
	return 0;
}

static int fat_calc_dir_size(struct inode *inode)
{
	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
	int ret, fclus, dclus;

	inode->i_size = 0;
	if (MSDOS_I(inode)->i_start == 0)
		return 0;

	ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
	if (ret < 0)
		return ret;
	inode->i_size = (fclus + 1) << sbi->cluster_bits;

	return 0;
}

static int fat_read_root(struct inode *inode)
{
	struct super_block *sb = inode->i_sb;
	struct msdos_sb_info *sbi = MSDOS_SB(sb);
	int error;

	MSDOS_I(inode)->file_cluster = MSDOS_I(inode)->disk_cluster = 0;
	MSDOS_I(inode)->i_pos = 0;
	inode->i_uid = sbi->options.fs_uid;
	inode->i_gid = sbi->options.fs_gid;
	inode->i_version++;
	inode->i_generation = 0;
	inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
	inode->i_op = sbi->dir_ops;
	inode->i_fop = &fat_dir_operations;
	if (sbi->fat_bits == 32) {
		MSDOS_I(inode)->i_start = sbi->root_cluster;
		error = fat_calc_dir_size(inode);
		if (error < 0)
			return error;
	} else {
		MSDOS_I(inode)->i_start = 0;
		inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
	}
	inode->i_blksize = sbi->cluster_size;
	inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
			   & ~((loff_t)sbi->cluster_size - 1)) >> 9;
	MSDOS_I(inode)->i_logstart = 0;
	MSDOS_I(inode)->mmu_private = inode->i_size;

	MSDOS_I(inode)->i_attrs = 0;
	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
	inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
	MSDOS_I(inode)->i_ctime_ms = 0;
	inode->i_nlink = fat_subdirs(inode)+2;

	return 0;
}

/*
 * a FAT file handle with fhtype 3 is
 *  0/  i_ino - for fast, reliable lookup if still in the cache
 *  1/  i_generation - to see if i_ino is still valid
 *          bit 0 == 0 iff directory
 *  2/  i_pos(8-39) - if ino has changed, but still in cache
 *  3/  i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
 *  4/  i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
 *
 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
 * of i_logstart is used to store the directory entry offset.
 */

static struct dentry *
fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype, 
	      int (*acceptable)(void *context, struct dentry *de),
	      void *context)
{
	if (fhtype != 3)
		return ERR_PTR(-ESTALE);
	if (len < 5)
		return ERR_PTR(-ESTALE);

	return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context);
}

static struct dentry *fat_get_dentry(struct super_block *sb, void *inump)
{
	struct inode *inode = NULL;
	struct dentry *result;
	__u32 *fh = inump;

	inode = iget(sb, fh[0]);
	if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) {
		if (inode)
			iput(inode);
		inode = NULL;
	}
	if (!inode) {
		loff_t i_pos;
		int i_logstart = fh[3] & 0x0fffffff;

		i_pos = (loff_t)fh[2] << 8;
		i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);

		/* try 2 - see if i_pos is in F-d-c
		 * require i_logstart to be the same
		 * Will fail if you truncate and then re-write
		 */

		inode = fat_iget(sb, i_pos);
		if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
			iput(inode);
			inode = NULL;
		}
	}
	if (!inode) {
		/* For now, do nothing
		 * What we could do is:
		 * follow the file starting at fh[4], and record
		 * the ".." entry, and the name of the fh[2] entry.
		 * The follow the ".." file finding the next step up.
		 * This way we build a path to the root of
		 * the tree. If this works, we lookup the path and so
		 * get this inode into the cache.
		 * Finally try the fat_iget lookup again
		 * If that fails, then weare totally out of luck
		 * But all that is for another day
		 */
	}
	if (!inode)
		return ERR_PTR(-ESTALE);

	
	/* now to find a dentry.
	 * If possible, get a well-connected one
	 */
	result = d_alloc_anon(inode);
	if (result == NULL) {
		iput(inode);
		return ERR_PTR(-ENOMEM);
	}
	result->d_op = sb->s_root->d_op;
	return result;
}

static int
fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
{
	int len = *lenp;
	struct inode *inode =  de->d_inode;
	u32 ipos_h, ipos_m, ipos_l;
	
	if (len < 5)
		return 255; /* no room */

	ipos_h = MSDOS_I(inode)->i_pos >> 8;
	ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
	ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
	*lenp = 5;
	fh[0] = inode->i_ino;
	fh[1] = inode->i_generation;
	fh[2] = ipos_h;
	fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
	spin_lock(&de->d_lock);
	fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
	spin_unlock(&de->d_lock);
	return 3;
}

static struct dentry *fat_get_parent(struct dentry *child)
{
	struct buffer_head *bh=NULL;
	struct msdos_dir_entry *de = NULL;
	struct dentry *parent = NULL;
	int res;
	loff_t i_pos = 0;
	struct inode *inode;

	lock_kernel();
	res = fat_scan(child->d_inode, MSDOS_DOTDOT, &bh, &de, &i_pos);

	if (res < 0)
		goto out;
	inode = fat_build_inode(child->d_sb, de, i_pos, &res);
	if (res)
		goto out;
	if (!inode)
		res = -EACCES;
	else {
		parent = d_alloc_anon(inode);
		if (!parent) {
			iput(inode);
			res = -ENOMEM;
		}
	}

 out:
	if(bh)
		brelse(bh);
	unlock_kernel();
	if (res)
		return ERR_PTR(res);
	else
		return parent;
}

static kmem_cache_t *fat_inode_cachep;

static struct inode *fat_alloc_inode(struct super_block *sb)
{
	struct msdos_inode_info *ei;
	ei = (struct msdos_inode_info *)kmem_cache_alloc(fat_inode_cachep, SLAB_KERNEL);
	if (!ei)
		return NULL;
	return &ei->vfs_inode;
}

static void fat_destroy_inode(struct inode *inode)
{
	kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
}

static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
	struct msdos_inode_info *ei = (struct msdos_inode_info *) foo;

	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
	    SLAB_CTOR_CONSTRUCTOR) {
		INIT_LIST_HEAD(&ei->i_fat_hash);
		inode_init_once(&ei->vfs_inode);
	}
}
 
int __init fat_init_inodecache(void)
{
	fat_inode_cachep = kmem_cache_create("fat_inode_cache",
					     sizeof(struct msdos_inode_info),
					     0, SLAB_RECLAIM_ACCOUNT,
					     init_once, NULL);
	if (fat_inode_cachep == NULL)
		return -ENOMEM;
	return 0;
}

void __exit fat_destroy_inodecache(void)
{
	if (kmem_cache_destroy(fat_inode_cachep))
		printk(KERN_INFO "fat_inode_cache: not all structures were freed\n");
}

static int fat_remount(struct super_block *sb, int *flags, char *data)
{
	*flags |= MS_NODIRATIME;
	return 0;
}

static struct super_operations fat_sops = { 
	.alloc_inode	= fat_alloc_inode,
	.destroy_inode	= fat_destroy_inode,
	.write_inode	= fat_write_inode,
	.delete_inode	= fat_delete_inode,
	.put_super	= fat_put_super,
	.statfs		= fat_statfs,
	.clear_inode	= fat_clear_inode,
	.remount_fs	= fat_remount,

	.read_inode	= make_bad_inode,

	.show_options	= fat_show_options,
};

static struct export_operations fat_export_ops = {
	.decode_fh	= fat_decode_fh,
	.encode_fh	= fat_encode_fh,
	.get_dentry	= fat_get_dentry,
	.get_parent	= fat_get_parent,
};

/*
 * Read the super block of an MS-DOS FS.
 */
int fat_fill_super(struct super_block *sb, void *data, int silent,
		   struct inode_operations *fs_dir_inode_ops, int isvfat)
{
	struct inode *root_inode = NULL;
	struct buffer_head *bh;
	struct fat_boot_sector *b;
	struct msdos_sb_info *sbi;
	u16 logical_sector_size;
	u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
	int debug, first;
	unsigned int media;
	long error;
	char buf[50];

	sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
	if (!sbi)
		return -ENOMEM;
	sb->s_fs_info = sbi;
	memset(sbi, 0, sizeof(struct msdos_sb_info));

	sb->s_flags |= MS_NODIRATIME;
	sb->s_magic = MSDOS_SUPER_MAGIC;
	sb->s_op = &fat_sops;
	sb->s_export_op = &fat_export_ops;
	sbi->dir_ops = fs_dir_inode_ops;

	error = parse_options(data, isvfat, &debug, &sbi->options);
	if (error)
		goto out_fail;

	fat_cache_init(sb);
	/* set up enough so that it can read an inode */
	init_MUTEX(&sbi->fat_lock);

	error = -EIO;
	sb_min_blocksize(sb, 512);
	bh = sb_bread(sb, 0);
	if (bh == NULL) {
		printk(KERN_ERR "FAT: unable to read boot sector\n");
		goto out_fail;
	}

	b = (struct fat_boot_sector *) bh->b_data;
	if (!b->reserved) {
		if (!silent)
			printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
		brelse(bh);
		goto out_invalid;
	}
	if (!b->fats) {
		if (!silent)
			printk(KERN_ERR "FAT: bogus number of FAT structure\n");
		brelse(bh);
		goto out_invalid;
	}

	/*
	 * Earlier we checked here that b->secs_track and b->head are nonzero,
	 * but it turns out valid FAT filesystems can have zero there.
	 */

	media = b->media;
	if (!FAT_VALID_MEDIA(media)) {
		if (!silent)
			printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
			       media);
		brelse(bh);
		goto out_invalid;
	}
	logical_sector_size = CF_LE_W(get_unaligned((__le16 *)&b->sector_size));
	if (!logical_sector_size
	    || (logical_sector_size & (logical_sector_size - 1))
	    || (logical_sector_size < 512)
	    || (PAGE_CACHE_SIZE < logical_sector_size)) {
		if (!silent)
			printk(KERN_ERR "FAT: bogus logical sector size %u\n",
			       logical_sector_size);
		brelse(bh);
		goto out_invalid;
	}
	sbi->sec_per_clus = b->sec_per_clus;
	if (!sbi->sec_per_clus
	    || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) {
		if (!silent)
			printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
			       sbi->sec_per_clus);
		brelse(bh);
		goto out_invalid;
	}

	if (logical_sector_size < sb->s_blocksize) {
		printk(KERN_ERR "FAT: logical sector size too small for device"
		       " (logical sector size = %u)\n", logical_sector_size);
		brelse(bh);
		goto out_fail;
	}
	if (logical_sector_size > sb->s_blocksize) {
		brelse(bh);

		if (!sb_set_blocksize(sb, logical_sector_size)) {