fs/minix/inode.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/fs/minix/inode.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
  *  Copyright (C) 1996  Gertjan van Wingerde
  *	Minix V2 fs support.
  *
  *  Modified for 680x0 by Andreas Schwab
  *  Updated to filesystem version 3 by Daniel Aragones
  */

 #include <linux/module.h>
 #include "minix.h"
 #include <linux/buffer_head.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/highuid.h>
 #include <linux/vfs.h>
 #include <linux/writeback.h>

 static int minix_write_inode(struct inode *inode,
 		struct writeback_control *wbc);
 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
 static int minix_remount (struct super_block * sb, int * flags, char * data);

 static void minix_evict_inode(struct inode *inode)
 {
 	truncate_inode_pages_final(&inode->i_data);
 	if (!inode->i_nlink) {
 		inode->i_size = 0;
 		minix_truncate(inode);
 	}
 	invalidate_inode_buffers(inode);
 	clear_inode(inode);
 	if (!inode->i_nlink)
 		minix_free_inode(inode);
 }

 static void minix_put_super(struct super_block *sb)
 {
 	int i;
 	struct minix_sb_info *sbi = minix_sb(sb);

 	if (!sb_rdonly(sb)) {
 		if (sbi->s_version != MINIX_V3)	 /* s_state is now out from V3 sb */
 			sbi->s_ms->s_state = sbi->s_mount_state;
 		mark_buffer_dirty(sbi->s_sbh);
 	}
 	for (i = 0; i < sbi->s_imap_blocks; i++)
 		brelse(sbi->s_imap[i]);
 	for (i = 0; i < sbi->s_zmap_blocks; i++)
 		brelse(sbi->s_zmap[i]);
 	brelse (sbi->s_sbh);
 	kfree(sbi->s_imap);
 	sb->s_fs_info = NULL;
 	kfree(sbi);
 }

 static struct kmem_cache * minix_inode_cachep;

 static struct inode *minix_alloc_inode(struct super_block *sb)
 {
 	struct minix_inode_info *ei;
 	ei = kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
 	if (!ei)
 		return NULL;
 	return &ei->vfs_inode;
 }

 static void minix_free_in_core_inode(struct inode *inode)
 {
 	kmem_cache_free(minix_inode_cachep, minix_i(inode));
 }

 static void init_once(void *foo)
 {
 	struct minix_inode_info *ei = (struct minix_inode_info *) foo;

 	inode_init_once(&ei->vfs_inode);
 }

 static int __init init_inodecache(void)
 {
 	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
 					     sizeof(struct minix_inode_info),
 					     0, (SLAB_RECLAIM_ACCOUNT|
 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 					     init_once);
 	if (minix_inode_cachep == NULL)
 		return -ENOMEM;
 	return 0;
 }

 static void destroy_inodecache(void)
 {
 	/*
 	 * Make sure all delayed rcu free inodes are flushed before we
 	 * destroy cache.
 	 */
 	rcu_barrier();
 	kmem_cache_destroy(minix_inode_cachep);
 }

 static const struct super_operations minix_sops = {
 	.alloc_inode	= minix_alloc_inode,
 	.free_inode	= minix_free_in_core_inode,
 	.write_inode	= minix_write_inode,
 	.evict_inode	= minix_evict_inode,
 	.put_super	= minix_put_super,
 	.statfs		= minix_statfs,
 	.remount_fs	= minix_remount,
 };

 static int minix_remount (struct super_block * sb, int * flags, char * data)
 {
 	struct minix_sb_info * sbi = minix_sb(sb);
 	struct minix_super_block * ms;

 	sync_filesystem(sb);
 	ms = sbi->s_ms;
 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
 		return 0;
 	if (*flags & SB_RDONLY) {
 		if (ms->s_state & MINIX_VALID_FS ||
 		    !(sbi->s_mount_state & MINIX_VALID_FS))
 			return 0;
 		/* Mounting a rw partition read-only. */
 		if (sbi->s_version != MINIX_V3)
 			ms->s_state = sbi->s_mount_state;
 		mark_buffer_dirty(sbi->s_sbh);
 	} else {
 	  	/* Mount a partition which is read-only, read-write. */
 		if (sbi->s_version != MINIX_V3) {
 			sbi->s_mount_state = ms->s_state;
 			ms->s_state &= ~MINIX_VALID_FS;
 		} else {
 			sbi->s_mount_state = MINIX_VALID_FS;
 		}
 		mark_buffer_dirty(sbi->s_sbh);

 		if (!(sbi->s_mount_state & MINIX_VALID_FS))
 			printk("MINIX-fs warning: remounting unchecked fs, "
 				"running fsck is recommended\n");
 		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
 			printk("MINIX-fs warning: remounting fs with errors, "
 				"running fsck is recommended\n");
 	}
 	return 0;
 }

 static bool minix_check_superblock(struct super_block *sb)
 {
 	struct minix_sb_info *sbi = minix_sb(sb);

 	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
 		return false;

 	/*
 	 * s_max_size must not exceed the block mapping limitation.  This check
 	 * is only needed for V1 filesystems, since V2/V3 support an extra level
 	 * of indirect blocks which places the limit well above U32_MAX.
 	 */
 	if (sbi->s_version == MINIX_V1 &&
 	    sb->s_maxbytes > (7 + 512 + 512*512) * BLOCK_SIZE)
 		return false;

 	return true;
 }

 static int minix_fill_super(struct super_block *s, void *data, int silent)
 {
 	struct buffer_head *bh;
 	struct buffer_head **map;
 	struct minix_super_block *ms;
 	struct minix3_super_block *m3s = NULL;
 	unsigned long i, block;
 	struct inode *root_inode;
 	struct minix_sb_info *sbi;
 	int ret = -EINVAL;

 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
 	if (!sbi)
 		return -ENOMEM;
 	s->s_fs_info = sbi;

 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
 	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));

 	if (!sb_set_blocksize(s, BLOCK_SIZE))
 		goto out_bad_hblock;

 	if (!(bh = sb_bread(s, 1)))
 		goto out_bad_sb;

 	ms = (struct minix_super_block *) bh->b_data;
 	sbi->s_ms = ms;
 	sbi->s_sbh = bh;
 	sbi->s_mount_state = ms->s_state;
 	sbi->s_ninodes = ms->s_ninodes;
 	sbi->s_nzones = ms->s_nzones;
 	sbi->s_imap_blocks = ms->s_imap_blocks;
 	sbi->s_zmap_blocks = ms->s_zmap_blocks;
 	sbi->s_firstdatazone = ms->s_firstdatazone;
 	sbi->s_log_zone_size = ms->s_log_zone_size;
 	s->s_maxbytes = ms->s_max_size;
 	s->s_magic = ms->s_magic;
 	if (s->s_magic == MINIX_SUPER_MAGIC) {
 		sbi->s_version = MINIX_V1;
 		sbi->s_dirsize = 16;
 		sbi->s_namelen = 14;
 		s->s_max_links = MINIX_LINK_MAX;
 	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
 		sbi->s_version = MINIX_V1;
 		sbi->s_dirsize = 32;
 		sbi->s_namelen = 30;
 		s->s_max_links = MINIX_LINK_MAX;
 	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
 		sbi->s_version = MINIX_V2;
 		sbi->s_nzones = ms->s_zones;
 		sbi->s_dirsize = 16;
 		sbi->s_namelen = 14;
 		s->s_max_links = MINIX2_LINK_MAX;
 	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
 		sbi->s_version = MINIX_V2;
 		sbi->s_nzones = ms->s_zones;
 		sbi->s_dirsize = 32;
 		sbi->s_namelen = 30;
 		s->s_max_links = MINIX2_LINK_MAX;
 	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
 		m3s = (struct minix3_super_block *) bh->b_data;
 		s->s_magic = m3s->s_magic;
 		sbi->s_imap_blocks = m3s->s_imap_blocks;
 		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
 		sbi->s_firstdatazone = m3s->s_firstdatazone;
 		sbi->s_log_zone_size = m3s->s_log_zone_size;
 		s->s_maxbytes = m3s->s_max_size;
 		sbi->s_ninodes = m3s->s_ninodes;
 		sbi->s_nzones = m3s->s_zones;
 		sbi->s_dirsize = 64;
 		sbi->s_namelen = 60;
 		sbi->s_version = MINIX_V3;
 		sbi->s_mount_state = MINIX_VALID_FS;
 		sb_set_blocksize(s, m3s->s_blocksize);
 		s->s_max_links = MINIX2_LINK_MAX;
 	} else
 		goto out_no_fs;

 	if (!minix_check_superblock(s))
 		goto out_illegal_sb;

 	/*
 	 * Allocate the buffer map to keep the superblock small.
 	 */
 	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
 	map = kzalloc(i, GFP_KERNEL);
 	if (!map)
 		goto out_no_map;
 	sbi->s_imap = &map[0];
 	sbi->s_zmap = &map[sbi->s_imap_blocks];

 	block=2;
 	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
 		if (!(sbi->s_imap[i]=sb_bread(s, block)))
 			goto out_no_bitmap;
 		block++;
 	}
 	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
 		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
 			goto out_no_bitmap;
 		block++;
 	}

 	minix_set_bit(0,sbi->s_imap[0]->b_data);
 	minix_set_bit(0,sbi->s_zmap[0]->b_data);

 	/* Apparently minix can create filesystems that allocate more blocks for
 	 * the bitmaps than needed.  We simply ignore that, but verify it didn't
 	 * create one with not enough blocks and bail out if so.
 	 */
 	block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
 	if (sbi->s_imap_blocks < block) {
 		printk("MINIX-fs: file system does not have enough "
 				"imap blocks allocated.  Refusing to mount.\n");
 		goto out_no_bitmap;
 	}

 	block = minix_blocks_needed(
 			(sbi->s_nzones - sbi->s_firstdatazone + 1),
 			s->s_blocksize);
 	if (sbi->s_zmap_blocks < block) {
 		printk("MINIX-fs: file system does not have enough "
 				"zmap blocks allocated.  Refusing to mount.\n");
 		goto out_no_bitmap;
 	}

 	/* set up enough so that it can read an inode */
 	s->s_op = &minix_sops;
 	s->s_time_min = 0;
 	s->s_time_max = U32_MAX;
 	root_inode = minix_iget(s, MINIX_ROOT_INO);
 	if (IS_ERR(root_inode)) {
 		ret = PTR_ERR(root_inode);
 		goto out_no_root;
 	}

 	ret = -ENOMEM;
 	s->s_root = d_make_root(root_inode);
 	if (!s->s_root)
 		goto out_no_root;

 	if (!sb_rdonly(s)) {
 		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
 			ms->s_state &= ~MINIX_VALID_FS;
 		mark_buffer_dirty(bh);
 	}
 	if (!(sbi->s_mount_state & MINIX_VALID_FS))
 		printk("MINIX-fs: mounting unchecked file system, "
 			"running fsck is recommended\n");
 	else if (sbi->s_mount_state & MINIX_ERROR_FS)
 		printk("MINIX-fs: mounting file system with errors, "
 			"running fsck is recommended\n");

 	return 0;

 out_no_root:
 	if (!silent)
 		printk("MINIX-fs: get root inode failed\n");
 	goto out_freemap;

 out_no_bitmap:
 	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
 out_freemap:
 	for (i = 0; i < sbi->s_imap_blocks; i++)
 		brelse(sbi->s_imap[i]);
 	for (i = 0; i < sbi->s_zmap_blocks; i++)
 		brelse(sbi->s_zmap[i]);
 	kfree(sbi->s_imap);
 	goto out_release;

 out_no_map:
 	ret = -ENOMEM;
 	if (!silent)
 		printk("MINIX-fs: can't allocate map\n");
 	goto out_release;

 out_illegal_sb:
 	if (!silent)
 		printk("MINIX-fs: bad superblock\n");
 	goto out_release;

 out_no_fs:
 	if (!silent)
 		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
 		       "on device %s.\n", s->s_id);
 out_release:
 	brelse(bh);
 	goto out;

 out_bad_hblock:
 	printk("MINIX-fs: blocksize too small for device\n");
 	goto out;

 out_bad_sb:
 	printk("MINIX-fs: unable to read superblock\n");
 out:
 	s->s_fs_info = NULL;
 	kfree(sbi);
 	return ret;
 }

 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct super_block *sb = dentry->d_sb;
 	struct minix_sb_info *sbi = minix_sb(sb);
 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 	buf->f_type = sb->s_magic;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
 	buf->f_bfree = minix_count_free_blocks(sb);
 	buf->f_bavail = buf->f_bfree;
 	buf->f_files = sbi->s_ninodes;
 	buf->f_ffree = minix_count_free_inodes(sb);
 	buf->f_namelen = sbi->s_namelen;
 	buf->f_fsid = u64_to_fsid(id);

 	return 0;
 }

 static int minix_get_block(struct inode *inode, sector_t block,
 		    struct buffer_head *bh_result, int create)
 {
 	if (INODE_VERSION(inode) == MINIX_V1)
 		return V1_minix_get_block(inode, block, bh_result, create);
 	else
 		return V2_minix_get_block(inode, block, bh_result, create);
 }

 static int minix_writepage(struct page *page, struct writeback_control *wbc)
 {
 	return block_write_full_page(page, minix_get_block, wbc);
 }

 static int minix_readpage(struct file *file, struct page *page)
 {
 	return block_read_full_page(page,minix_get_block);
 }

 int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
 {
 	return __block_write_begin(page, pos, len, minix_get_block);
 }

 static void minix_write_failed(struct address_space *mapping, loff_t to)
 {
 	struct inode *inode = mapping->host;

 	if (to > inode->i_size) {
 		truncate_pagecache(inode, inode->i_size);
 		minix_truncate(inode);
 	}
 }

 static int minix_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
 	int ret;

 	ret = block_write_begin(mapping, pos, len, flags, pagep,
 				minix_get_block);
 	if (unlikely(ret))
 		minix_write_failed(mapping, pos + len);

 	return ret;
 }

 static sector_t minix_bmap(struct address_space *mapping, sector_t block)
 {
 	return generic_block_bmap(mapping,block,minix_get_block);
 }

 static const struct address_space_operations minix_aops = {
 	.dirty_folio	= block_dirty_folio,
 	.invalidate_folio = block_invalidate_folio,
 	.readpage = minix_readpage,
 	.writepage = minix_writepage,
 	.write_begin = minix_write_begin,
 	.write_end = generic_write_end,
 	.bmap = minix_bmap
 };

 static const struct inode_operations minix_symlink_inode_operations = {
 	.get_link	= page_get_link,
 	.getattr	= minix_getattr,
 };

 void minix_set_inode(struct inode *inode, dev_t rdev)
 {
 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = &minix_file_inode_operations;
 		inode->i_fop = &minix_file_operations;
 		inode->i_mapping->a_ops = &minix_aops;
 	} else if (S_ISDIR(inode->i_mode)) {
 		inode->i_op = &minix_dir_inode_operations;
 		inode->i_fop = &minix_dir_operations;
 		inode->i_mapping->a_ops = &minix_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &minix_symlink_inode_operations;
 		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &minix_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, rdev);
 }

 /*
  * The minix V1 function to read an inode.
  */
 static struct inode *V1_minix_iget(struct inode *inode)
 {
 	struct buffer_head * bh;
 	struct minix_inode * raw_inode;
 	struct minix_inode_info *minix_inode = minix_i(inode);
 	int i;

 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
 	if (!raw_inode) {
 		iget_failed(inode);
 		return ERR_PTR(-EIO);
 	}
 	if (raw_inode->i_nlinks == 0) {
 		printk("MINIX-fs: deleted inode referenced: %lu\n",
 		       inode->i_ino);
 		brelse(bh);
 		iget_failed(inode);
 		return ERR_PTR(-ESTALE);
 	}
 	inode->i_mode = raw_inode->i_mode;
 	i_uid_write(inode, raw_inode->i_uid);
 	i_gid_write(inode, raw_inode->i_gid);
 	set_nlink(inode, raw_inode->i_nlinks);
 	inode->i_size = raw_inode->i_size;
 	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
 	inode->i_mtime.tv_nsec = 0;
 	inode->i_atime.tv_nsec = 0;
 	inode->i_ctime.tv_nsec = 0;
 	inode->i_blocks = 0;
 	for (i = 0; i < 9; i++)
 		minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
 	brelse(bh);
 	unlock_new_inode(inode);
 	return inode;
 }

 /*
  * The minix V2 function to read an inode.
  */
 static struct inode *V2_minix_iget(struct inode *inode)
 {
 	struct buffer_head * bh;
 	struct minix2_inode * raw_inode;
 	struct minix_inode_info *minix_inode = minix_i(inode);
 	int i;

 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
 	if (!raw_inode) {
 		iget_failed(inode);
 		return ERR_PTR(-EIO);
 	}
 	if (raw_inode->i_nlinks == 0) {
 		printk("MINIX-fs: deleted inode referenced: %lu\n",
 		       inode->i_ino);
 		brelse(bh);
 		iget_failed(inode);
 		return ERR_PTR(-ESTALE);
 	}
 	inode->i_mode = raw_inode->i_mode;
 	i_uid_write(inode, raw_inode->i_uid);
 	i_gid_write(inode, raw_inode->i_gid);
 	set_nlink(inode, raw_inode->i_nlinks);
 	inode->i_size = raw_inode->i_size;
 	inode->i_mtime.tv_sec = raw_inode->i_mtime;
 	inode->i_atime.tv_sec = raw_inode->i_atime;
 	inode->i_ctime.tv_sec = raw_inode->i_ctime;
 	inode->i_mtime.tv_nsec = 0;
 	inode->i_atime.tv_nsec = 0;
 	inode->i_ctime.tv_nsec = 0;
 	inode->i_blocks = 0;
 	for (i = 0; i < 10; i++)
 		minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
 	brelse(bh);
 	unlock_new_inode(inode);
 	return inode;
 }

 /*
  * The global function to read an inode.
  */
 struct inode *minix_iget(struct super_block *sb, unsigned long ino)
 {
 	struct inode *inode;

 	inode = iget_locked(sb, ino);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 	if (!(inode->i_state & I_NEW))
 		return inode;

 	if (INODE_VERSION(inode) == MINIX_V1)
 		return V1_minix_iget(inode);
 	else
 		return V2_minix_iget(inode);
 }

 /*
  * The minix V1 function to synchronize an inode.
  */
 static struct buffer_head * V1_minix_update_inode(struct inode * inode)
 {
 	struct buffer_head * bh;
 	struct minix_inode * raw_inode;
 	struct minix_inode_info *minix_inode = minix_i(inode);
 	int i;

 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
 	if (!raw_inode)
 		return NULL;
 	raw_inode->i_mode = inode->i_mode;
 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
 	raw_inode->i_nlinks = inode->i_nlink;
 	raw_inode->i_size = inode->i_size;
 	raw_inode->i_time = inode->i_mtime.tv_sec;
 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
 	else for (i = 0; i < 9; i++)
 		raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
 	mark_buffer_dirty(bh);
 	return bh;
 }

 /*
  * The minix V2 function to synchronize an inode.
  */
 static struct buffer_head * V2_minix_update_inode(struct inode * inode)
 {
 	struct buffer_head * bh;
 	struct minix2_inode * raw_inode;
 	struct minix_inode_info *minix_inode = minix_i(inode);
 	int i;

 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
 	if (!raw_inode)
 		return NULL;
 	raw_inode->i_mode = inode->i_mode;
 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
 	raw_inode->i_nlinks = inode->i_nlink;
 	raw_inode->i_size = inode->i_size;
 	raw_inode->i_mtime = inode->i_mtime.tv_sec;
 	raw_inode->i_atime = inode->i_atime.tv_sec;
 	raw_inode->i_ctime = inode->i_ctime.tv_sec;
 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
 	else for (i = 0; i < 10; i++)
 		raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
 	mark_buffer_dirty(bh);
 	return bh;
 }

 static int minix_write_inode(struct inode *inode, struct writeback_control *wbc)
 {
 	int err = 0;
 	struct buffer_head *bh;

 	if (INODE_VERSION(inode) == MINIX_V1)
 		bh = V1_minix_update_inode(inode);
 	else
 		bh = V2_minix_update_inode(inode);
 	if (!bh)
 		return -EIO;
 	if (wbc->sync_mode == WB_SYNC_ALL && buffer_dirty(bh)) {
 		sync_dirty_buffer(bh);
 		if (buffer_req(bh) && !buffer_uptodate(bh)) {
 			printk("IO error syncing minix inode [%s:%08lx]\n",
 				inode->i_sb->s_id, inode->i_ino);
 			err = -EIO;
 		}
 	}
 	brelse (bh);
 	return err;
 }

 int minix_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		  struct kstat *stat, u32 request_mask, unsigned int flags)
 {
 	struct super_block *sb = path->dentry->d_sb;
 	struct inode *inode = d_inode(path->dentry);

 	generic_fillattr(&init_user_ns, inode, stat);
 	if (INODE_VERSION(inode) == MINIX_V1)
 		stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
 	else
 		stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
 	stat->blksize = sb->s_blocksize;
 	return 0;
 }

 /*
  * The function that is called for file truncation.
  */
 void minix_truncate(struct inode * inode)
 {
 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
 		return;
 	if (INODE_VERSION(inode) == MINIX_V1)
 		V1_minix_truncate(inode);
 	else
 		V2_minix_truncate(inode);
 }

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

 static struct file_system_type minix_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "minix",
 	.mount		= minix_mount,
 	.kill_sb	= kill_block_super,
 	.fs_flags	= FS_REQUIRES_DEV,
 };
 MODULE_ALIAS_FS("minix");

 static int __init init_minix_fs(void)
 {
 	int err = init_inodecache();
 	if (err)
 		goto out1;
 	err = register_filesystem(&minix_fs_type);
 	if (err)
 		goto out;
 	return 0;
 out:
 	destroy_inodecache();
 out1:
 	return err;
 }

 static void __exit exit_minix_fs(void)
 {
         unregister_filesystem(&minix_fs_type);
 	destroy_inodecache();
 }

 module_init(init_minix_fs)
 module_exit(exit_minix_fs)
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* linux/fs/minix/inode.c
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*
	* Copyright (C) 1996 Gertjan van Wingerde
	* Minix V2 fs support.
	*
	* Modified for 680x0 by Andreas Schwab
	* Updated to filesystem version 3 by Daniel Aragones
	*/

	#include <linux/module.h>
	#include "minix.h"
	#include <linux/buffer_head.h>
	#include <linux/slab.h>
	#include <linux/init.h>
	#include <linux/highuid.h>
	#include <linux/vfs.h>
	#include <linux/writeback.h>

	static int minix_write_inode(struct inode *inode,
	struct writeback_control *wbc);
	static int minix_statfs(struct dentry dentry, struct kstatfs buf);
	static int minix_remount (struct super_block * sb, int * flags, char * data);

	static void minix_evict_inode(struct inode *inode)
	{
	truncate_inode_pages_final(&inode->i_data);
	if (!inode->i_nlink) {
	inode->i_size = 0;
	minix_truncate(inode);
	}
	invalidate_inode_buffers(inode);
	clear_inode(inode);
	if (!inode->i_nlink)
	minix_free_inode(inode);
	}

	static void minix_put_super(struct super_block *sb)
	{
	int i;
	struct minix_sb_info *sbi = minix_sb(sb);

	if (!sb_rdonly(sb)) {
	if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
	sbi->s_ms->s_state = sbi->s_mount_state;
	mark_buffer_dirty(sbi->s_sbh);
	}
	for (i = 0; i < sbi->s_imap_blocks; i++)
	brelse(sbi->s_imap[i]);
	for (i = 0; i < sbi->s_zmap_blocks; i++)
	brelse(sbi->s_zmap[i]);
	brelse (sbi->s_sbh);
	kfree(sbi->s_imap);
	sb->s_fs_info = NULL;
	kfree(sbi);
	}

	static struct kmem_cache * minix_inode_cachep;

	static struct inode minix_alloc_inode(struct super_block sb)
	{
	struct minix_inode_info *ei;
	ei = kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
	if (!ei)
	return NULL;
	return &ei->vfs_inode;
	}

	static void minix_free_in_core_inode(struct inode *inode)
	{
	kmem_cache_free(minix_inode_cachep, minix_i(inode));
	}

	static void init_once(void *foo)
	{
	struct minix_inode_info ei = (struct minix_inode_info ) foo;

	inode_init_once(&ei->vfs_inode);
	}

	static int __init init_inodecache(void)
	{
	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
	sizeof(struct minix_inode_info),
	0, (SLAB_RECLAIM_ACCOUNT\|
	SLAB_MEM_SPREAD\|SLAB_ACCOUNT),
	init_once);
	if (minix_inode_cachep == NULL)
	return -ENOMEM;
	return 0;
	}

	static void destroy_inodecache(void)
	{
	/*
	* Make sure all delayed rcu free inodes are flushed before we
	* destroy cache.
	*/
	rcu_barrier();
	kmem_cache_destroy(minix_inode_cachep);
	}

	static const struct super_operations minix_sops = {
	.alloc_inode = minix_alloc_inode,
	.free_inode = minix_free_in_core_inode,
	.write_inode = minix_write_inode,
	.evict_inode = minix_evict_inode,
	.put_super = minix_put_super,
	.statfs = minix_statfs,
	.remount_fs = minix_remount,
	};

	static int minix_remount (struct super_block * sb, int * flags, char * data)
	{
	struct minix_sb_info * sbi = minix_sb(sb);
	struct minix_super_block * ms;

	sync_filesystem(sb);
	ms = sbi->s_ms;
	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
	return 0;
	if (*flags & SB_RDONLY) {
	if (ms->s_state & MINIX_VALID_FS \|\|
	!(sbi->s_mount_state & MINIX_VALID_FS))
	return 0;
	/* Mounting a rw partition read-only. */
	if (sbi->s_version != MINIX_V3)
	ms->s_state = sbi->s_mount_state;
	mark_buffer_dirty(sbi->s_sbh);
	} else {
	/* Mount a partition which is read-only, read-write. */
	if (sbi->s_version != MINIX_V3) {
	sbi->s_mount_state = ms->s_state;
	ms->s_state &= ~MINIX_VALID_FS;
	} else {
	sbi->s_mount_state = MINIX_VALID_FS;
	}
	mark_buffer_dirty(sbi->s_sbh);

	if (!(sbi->s_mount_state & MINIX_VALID_FS))
	printk("MINIX-fs warning: remounting unchecked fs, "
	"running fsck is recommended\n");
	else if ((sbi->s_mount_state & MINIX_ERROR_FS))
	printk("MINIX-fs warning: remounting fs with errors, "
	"running fsck is recommended\n");
	}
	return 0;
	}

	static bool minix_check_superblock(struct super_block *sb)
	{
	struct minix_sb_info *sbi = minix_sb(sb);

	if (sbi->s_imap_blocks == 0 \|\| sbi->s_zmap_blocks == 0)
	return false;

	/*
	* s_max_size must not exceed the block mapping limitation. This check
	* is only needed for V1 filesystems, since V2/V3 support an extra level
	* of indirect blocks which places the limit well above U32_MAX.
	*/
	if (sbi->s_version == MINIX_V1 &&
	sb->s_maxbytes > (7 + 512 + 512512) BLOCK_SIZE)
	return false;

	return true;
	}

	static int minix_fill_super(struct super_block s, void data, int silent)
	{
	struct buffer_head *bh;
	struct buffer_head **map;
	struct minix_super_block *ms;
	struct minix3_super_block *m3s = NULL;
	unsigned long i, block;
	struct inode *root_inode;
	struct minix_sb_info *sbi;
	int ret = -EINVAL;

	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
	if (!sbi)
	return -ENOMEM;
	s->s_fs_info = sbi;

	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));

	if (!sb_set_blocksize(s, BLOCK_SIZE))
	goto out_bad_hblock;

	if (!(bh = sb_bread(s, 1)))
	goto out_bad_sb;

	ms = (struct minix_super_block *) bh->b_data;
	sbi->s_ms = ms;
	sbi->s_sbh = bh;
	sbi->s_mount_state = ms->s_state;
	sbi->s_ninodes = ms->s_ninodes;
	sbi->s_nzones = ms->s_nzones;
	sbi->s_imap_blocks = ms->s_imap_blocks;
	sbi->s_zmap_blocks = ms->s_zmap_blocks;
	sbi->s_firstdatazone = ms->s_firstdatazone;
	sbi->s_log_zone_size = ms->s_log_zone_size;
	s->s_maxbytes = ms->s_max_size;
	s->s_magic = ms->s_magic;
	if (s->s_magic == MINIX_SUPER_MAGIC) {
	sbi->s_version = MINIX_V1;
	sbi->s_dirsize = 16;
	sbi->s_namelen = 14;
	s->s_max_links = MINIX_LINK_MAX;
	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
	sbi->s_version = MINIX_V1;
	sbi->s_dirsize = 32;
	sbi->s_namelen = 30;
	s->s_max_links = MINIX_LINK_MAX;
	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
	sbi->s_version = MINIX_V2;
	sbi->s_nzones = ms->s_zones;
	sbi->s_dirsize = 16;
	sbi->s_namelen = 14;
	s->s_max_links = MINIX2_LINK_MAX;
	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
	sbi->s_version = MINIX_V2;
	sbi->s_nzones = ms->s_zones;
	sbi->s_dirsize = 32;
	sbi->s_namelen = 30;
	s->s_max_links = MINIX2_LINK_MAX;
	} else if ( (__u16 )(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
	m3s = (struct minix3_super_block *) bh->b_data;
	s->s_magic = m3s->s_magic;
	sbi->s_imap_blocks = m3s->s_imap_blocks;
	sbi->s_zmap_blocks = m3s->s_zmap_blocks;
	sbi->s_firstdatazone = m3s->s_firstdatazone;
	sbi->s_log_zone_size = m3s->s_log_zone_size;
	s->s_maxbytes = m3s->s_max_size;
	sbi->s_ninodes = m3s->s_ninodes;
	sbi->s_nzones = m3s->s_zones;
	sbi->s_dirsize = 64;
	sbi->s_namelen = 60;
	sbi->s_version = MINIX_V3;
	sbi->s_mount_state = MINIX_VALID_FS;
	sb_set_blocksize(s, m3s->s_blocksize);
	s->s_max_links = MINIX2_LINK_MAX;
	} else
	goto out_no_fs;

	if (!minix_check_superblock(s))
	goto out_illegal_sb;

	/*
	* Allocate the buffer map to keep the superblock small.
	*/
	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
	map = kzalloc(i, GFP_KERNEL);
	if (!map)
	goto out_no_map;
	sbi->s_imap = &map[0];
	sbi->s_zmap = &map[sbi->s_imap_blocks];

	block=2;
	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
	if (!(sbi->s_imap[i]=sb_bread(s, block)))
	goto out_no_bitmap;
	block++;
	}
	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
	if (!(sbi->s_zmap[i]=sb_bread(s, block)))
	goto out_no_bitmap;
	block++;
	}

	minix_set_bit(0,sbi->s_imap[0]->b_data);
	minix_set_bit(0,sbi->s_zmap[0]->b_data);

	/* Apparently minix can create filesystems that allocate more blocks for
	* the bitmaps than needed. We simply ignore that, but verify it didn't
	* create one with not enough blocks and bail out if so.
	*/
	block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
	if (sbi->s_imap_blocks < block) {
	printk("MINIX-fs: file system does not have enough "
	"imap blocks allocated. Refusing to mount.\n");
	goto out_no_bitmap;
	}

	block = minix_blocks_needed(
	(sbi->s_nzones - sbi->s_firstdatazone + 1),
	s->s_blocksize);
	if (sbi->s_zmap_blocks < block) {
	printk("MINIX-fs: file system does not have enough "
	"zmap blocks allocated. Refusing to mount.\n");
	goto out_no_bitmap;
	}

	/* set up enough so that it can read an inode */
	s->s_op = &minix_sops;
	s->s_time_min = 0;
	s->s_time_max = U32_MAX;
	root_inode = minix_iget(s, MINIX_ROOT_INO);
	if (IS_ERR(root_inode)) {
	ret = PTR_ERR(root_inode);
	goto out_no_root;
	}

	ret = -ENOMEM;
	s->s_root = d_make_root(root_inode);
	if (!s->s_root)
	goto out_no_root;

	if (!sb_rdonly(s)) {
	if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
	ms->s_state &= ~MINIX_VALID_FS;
	mark_buffer_dirty(bh);
	}
	if (!(sbi->s_mount_state & MINIX_VALID_FS))
	printk("MINIX-fs: mounting unchecked file system, "
	"running fsck is recommended\n");
	else if (sbi->s_mount_state & MINIX_ERROR_FS)
	printk("MINIX-fs: mounting file system with errors, "
	"running fsck is recommended\n");

	return 0;

	out_no_root:
	if (!silent)
	printk("MINIX-fs: get root inode failed\n");
	goto out_freemap;

	out_no_bitmap:
	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
	out_freemap:
	for (i = 0; i < sbi->s_imap_blocks; i++)
	brelse(sbi->s_imap[i]);
	for (i = 0; i < sbi->s_zmap_blocks; i++)
	brelse(sbi->s_zmap[i]);
	kfree(sbi->s_imap);
	goto out_release;

	out_no_map:
	ret = -ENOMEM;
	if (!silent)
	printk("MINIX-fs: can't allocate map\n");
	goto out_release;

	out_illegal_sb:
	if (!silent)
	printk("MINIX-fs: bad superblock\n");
	goto out_release;

	out_no_fs:
	if (!silent)
	printk("VFS: Can't find a Minix filesystem V1 \| V2 \| V3 "
	"on device %s.\n", s->s_id);
	out_release:
	brelse(bh);
	goto out;

	out_bad_hblock:
	printk("MINIX-fs: blocksize too small for device\n");
	goto out;

	out_bad_sb:
	printk("MINIX-fs: unable to read superblock\n");
	out:
	s->s_fs_info = NULL;
	kfree(sbi);
	return ret;
	}

	static int minix_statfs(struct dentry dentry, struct kstatfs buf)
	{
	struct super_block *sb = dentry->d_sb;
	struct minix_sb_info *sbi = minix_sb(sb);
	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
	buf->f_type = sb->s_magic;
	buf->f_bsize = sb->s_blocksize;
	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
	buf->f_bfree = minix_count_free_blocks(sb);
	buf->f_bavail = buf->f_bfree;
	buf->f_files = sbi->s_ninodes;
	buf->f_ffree = minix_count_free_inodes(sb);
	buf->f_namelen = sbi->s_namelen;
	buf->f_fsid = u64_to_fsid(id);

	return 0;
	}

	static int minix_get_block(struct inode *inode, sector_t block,
	struct buffer_head *bh_result, int create)
	{
	if (INODE_VERSION(inode) == MINIX_V1)
	return V1_minix_get_block(inode, block, bh_result, create);
	else
	return V2_minix_get_block(inode, block, bh_result, create);
	}

	static int minix_writepage(struct page page, struct writeback_control wbc)
	{
	return block_write_full_page(page, minix_get_block, wbc);
	}

	static int minix_readpage(struct file file, struct page page)
	{
	return block_read_full_page(page,minix_get_block);
	}

	int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
	{
	return __block_write_begin(page, pos, len, minix_get_block);
	}

	static void minix_write_failed(struct address_space *mapping, loff_t to)
	{
	struct inode *inode = mapping->host;

	if (to > inode->i_size) {
	truncate_pagecache(inode, inode->i_size);
	minix_truncate(inode);
	}
	}

	static int minix_write_begin(struct file file, struct address_space mapping,
	loff_t pos, unsigned len, unsigned flags,
	struct page pagep, void fsdata)
	{
	int ret;

	ret = block_write_begin(mapping, pos, len, flags, pagep,
	minix_get_block);
	if (unlikely(ret))
	minix_write_failed(mapping, pos + len);

	return ret;
	}

	static sector_t minix_bmap(struct address_space *mapping, sector_t block)
	{
	return generic_block_bmap(mapping,block,minix_get_block);
	}

	static const struct address_space_operations minix_aops = {
	.dirty_folio = block_dirty_folio,
	.invalidate_folio = block_invalidate_folio,
	.readpage = minix_readpage,
	.writepage = minix_writepage,
	.write_begin = minix_write_begin,
	.write_end = generic_write_end,
	.bmap = minix_bmap
	};

	static const struct inode_operations minix_symlink_inode_operations = {
	.get_link = page_get_link,
	.getattr = minix_getattr,
	};

	void minix_set_inode(struct inode *inode, dev_t rdev)
	{
	if (S_ISREG(inode->i_mode)) {
	inode->i_op = &minix_file_inode_operations;
	inode->i_fop = &minix_file_operations;
	inode->i_mapping->a_ops = &minix_aops;
	} else if (S_ISDIR(inode->i_mode)) {
	inode->i_op = &minix_dir_inode_operations;
	inode->i_fop = &minix_dir_operations;
	inode->i_mapping->a_ops = &minix_aops;
	} else if (S_ISLNK(inode->i_mode)) {
	inode->i_op = &minix_symlink_inode_operations;
	inode_nohighmem(inode);
	inode->i_mapping->a_ops = &minix_aops;
	} else
	init_special_inode(inode, inode->i_mode, rdev);
	}

	/*
	* The minix V1 function to read an inode.
	*/
	static struct inode V1_minix_iget(struct inode inode)
	{
	struct buffer_head * bh;
	struct minix_inode * raw_inode;
	struct minix_inode_info *minix_inode = minix_i(inode);
	int i;

	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
	if (!raw_inode) {
	iget_failed(inode);
	return ERR_PTR(-EIO);
	}
	if (raw_inode->i_nlinks == 0) {
	printk("MINIX-fs: deleted inode referenced: %lu\n",
	inode->i_ino);
	brelse(bh);
	iget_failed(inode);
	return ERR_PTR(-ESTALE);
	}
	inode->i_mode = raw_inode->i_mode;
	i_uid_write(inode, raw_inode->i_uid);
	i_gid_write(inode, raw_inode->i_gid);
	set_nlink(inode, raw_inode->i_nlinks);
	inode->i_size = raw_inode->i_size;
	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
	inode->i_mtime.tv_nsec = 0;
	inode->i_atime.tv_nsec = 0;
	inode->i_ctime.tv_nsec = 0;
	inode->i_blocks = 0;
	for (i = 0; i < 9; i++)
	minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
	brelse(bh);
	unlock_new_inode(inode);
	return inode;
	}

	/*
	* The minix V2 function to read an inode.
	*/
	static struct inode V2_minix_iget(struct inode inode)
	{
	struct buffer_head * bh;
	struct minix2_inode * raw_inode;
	struct minix_inode_info *minix_inode = minix_i(inode);
	int i;

	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
	if (!raw_inode) {
	iget_failed(inode);
	return ERR_PTR(-EIO);
	}
	if (raw_inode->i_nlinks == 0) {
	printk("MINIX-fs: deleted inode referenced: %lu\n",
	inode->i_ino);
	brelse(bh);
	iget_failed(inode);
	return ERR_PTR(-ESTALE);
	}
	inode->i_mode = raw_inode->i_mode;
	i_uid_write(inode, raw_inode->i_uid);
	i_gid_write(inode, raw_inode->i_gid);
	set_nlink(inode, raw_inode->i_nlinks);
	inode->i_size = raw_inode->i_size;
	inode->i_mtime.tv_sec = raw_inode->i_mtime;
	inode->i_atime.tv_sec = raw_inode->i_atime;
	inode->i_ctime.tv_sec = raw_inode->i_ctime;
	inode->i_mtime.tv_nsec = 0;
	inode->i_atime.tv_nsec = 0;
	inode->i_ctime.tv_nsec = 0;
	inode->i_blocks = 0;
	for (i = 0; i < 10; i++)
	minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
	brelse(bh);
	unlock_new_inode(inode);
	return inode;
	}

	/*
	* The global function to read an inode.
	*/
	struct inode minix_iget(struct super_block sb, unsigned long ino)
	{
	struct inode *inode;

	inode = iget_locked(sb, ino);
	if (!inode)
	return ERR_PTR(-ENOMEM);
	if (!(inode->i_state & I_NEW))
	return inode;

	if (INODE_VERSION(inode) == MINIX_V1)
	return V1_minix_iget(inode);
	else
	return V2_minix_iget(inode);
	}

	/*
	* The minix V1 function to synchronize an inode.
	*/
	static struct buffer_head * V1_minix_update_inode(struct inode * inode)
	{
	struct buffer_head * bh;
	struct minix_inode * raw_inode;
	struct minix_inode_info *minix_inode = minix_i(inode);
	int i;

	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
	if (!raw_inode)
	return NULL;
	raw_inode->i_mode = inode->i_mode;
	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
	raw_inode->i_nlinks = inode->i_nlink;
	raw_inode->i_size = inode->i_size;
	raw_inode->i_time = inode->i_mtime.tv_sec;
	if (S_ISCHR(inode->i_mode) \|\| S_ISBLK(inode->i_mode))
	raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
	else for (i = 0; i < 9; i++)
	raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
	mark_buffer_dirty(bh);
	return bh;
	}

	/*
	* The minix V2 function to synchronize an inode.
	*/
	static struct buffer_head * V2_minix_update_inode(struct inode * inode)
	{
	struct buffer_head * bh;
	struct minix2_inode * raw_inode;
	struct minix_inode_info *minix_inode = minix_i(inode);
	int i;

	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
	if (!raw_inode)
	return NULL;
	raw_inode->i_mode = inode->i_mode;
	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
	raw_inode->i_nlinks = inode->i_nlink;
	raw_inode->i_size = inode->i_size;
	raw_inode->i_mtime = inode->i_mtime.tv_sec;
	raw_inode->i_atime = inode->i_atime.tv_sec;
	raw_inode->i_ctime = inode->i_ctime.tv_sec;
	if (S_ISCHR(inode->i_mode) \|\| S_ISBLK(inode->i_mode))
	raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
	else for (i = 0; i < 10; i++)
	raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
	mark_buffer_dirty(bh);
	return bh;
	}

	static int minix_write_inode(struct inode inode, struct writeback_control wbc)
	{
	int err = 0;
	struct buffer_head *bh;

	if (INODE_VERSION(inode) == MINIX_V1)
	bh = V1_minix_update_inode(inode);
	else
	bh = V2_minix_update_inode(inode);
	if (!bh)
	return -EIO;
	if (wbc->sync_mode == WB_SYNC_ALL && buffer_dirty(bh)) {
	sync_dirty_buffer(bh);
	if (buffer_req(bh) && !buffer_uptodate(bh)) {
	printk("IO error syncing minix inode [%s:%08lx]\n",
	inode->i_sb->s_id, inode->i_ino);
	err = -EIO;
	}
	}
	brelse (bh);
	return err;
	}

	int minix_getattr(struct user_namespace mnt_userns, const struct path path,
	struct kstat *stat, u32 request_mask, unsigned int flags)
	{
	struct super_block *sb = path->dentry->d_sb;
	struct inode *inode = d_inode(path->dentry);

	generic_fillattr(&init_user_ns, inode, stat);
	if (INODE_VERSION(inode) == MINIX_V1)
	stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
	else
	stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
	stat->blksize = sb->s_blocksize;
	return 0;
	}

	/*
	* The function that is called for file truncation.
	*/
	void minix_truncate(struct inode * inode)
	{
	if (!(S_ISREG(inode->i_mode) \|\| S_ISDIR(inode->i_mode) \|\| S_ISLNK(inode->i_mode)))
	return;
	if (INODE_VERSION(inode) == MINIX_V1)
	V1_minix_truncate(inode);
	else
	V2_minix_truncate(inode);
	}

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

	static struct file_system_type minix_fs_type = {
	.owner = THIS_MODULE,
	.name = "minix",
	.mount = minix_mount,
	.kill_sb = kill_block_super,
	.fs_flags = FS_REQUIRES_DEV,
	};
	MODULE_ALIAS_FS("minix");

	static int __init init_minix_fs(void)
	{
	int err = init_inodecache();
	if (err)
	goto out1;
	err = register_filesystem(&minix_fs_type);
	if (err)
	goto out;
	return 0;
	out:
	destroy_inodecache();
	out1:
	return err;
	}

	static void __exit exit_minix_fs(void)
	{
	unregister_filesystem(&minix_fs_type);
	destroy_inodecache();
	}

	module_init(init_minix_fs)
	module_exit(exit_minix_fs)
	MODULE_LICENSE("GPL");