cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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inode.c (19484B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  linux/fs/minix/inode.c
      4 *
      5 *  Copyright (C) 1991, 1992  Linus Torvalds
      6 *
      7 *  Copyright (C) 1996  Gertjan van Wingerde
      8 *	Minix V2 fs support.
      9 *
     10 *  Modified for 680x0 by Andreas Schwab
     11 *  Updated to filesystem version 3 by Daniel Aragones
     12 */
     13
     14#include <linux/module.h>
     15#include "minix.h"
     16#include <linux/buffer_head.h>
     17#include <linux/slab.h>
     18#include <linux/init.h>
     19#include <linux/highuid.h>
     20#include <linux/vfs.h>
     21#include <linux/writeback.h>
     22
     23static int minix_write_inode(struct inode *inode,
     24		struct writeback_control *wbc);
     25static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
     26static int minix_remount (struct super_block * sb, int * flags, char * data);
     27
     28static void minix_evict_inode(struct inode *inode)
     29{
     30	truncate_inode_pages_final(&inode->i_data);
     31	if (!inode->i_nlink) {
     32		inode->i_size = 0;
     33		minix_truncate(inode);
     34	}
     35	invalidate_inode_buffers(inode);
     36	clear_inode(inode);
     37	if (!inode->i_nlink)
     38		minix_free_inode(inode);
     39}
     40
     41static void minix_put_super(struct super_block *sb)
     42{
     43	int i;
     44	struct minix_sb_info *sbi = minix_sb(sb);
     45
     46	if (!sb_rdonly(sb)) {
     47		if (sbi->s_version != MINIX_V3)	 /* s_state is now out from V3 sb */
     48			sbi->s_ms->s_state = sbi->s_mount_state;
     49		mark_buffer_dirty(sbi->s_sbh);
     50	}
     51	for (i = 0; i < sbi->s_imap_blocks; i++)
     52		brelse(sbi->s_imap[i]);
     53	for (i = 0; i < sbi->s_zmap_blocks; i++)
     54		brelse(sbi->s_zmap[i]);
     55	brelse (sbi->s_sbh);
     56	kfree(sbi->s_imap);
     57	sb->s_fs_info = NULL;
     58	kfree(sbi);
     59}
     60
     61static struct kmem_cache * minix_inode_cachep;
     62
     63static struct inode *minix_alloc_inode(struct super_block *sb)
     64{
     65	struct minix_inode_info *ei;
     66	ei = alloc_inode_sb(sb, minix_inode_cachep, GFP_KERNEL);
     67	if (!ei)
     68		return NULL;
     69	return &ei->vfs_inode;
     70}
     71
     72static void minix_free_in_core_inode(struct inode *inode)
     73{
     74	kmem_cache_free(minix_inode_cachep, minix_i(inode));
     75}
     76
     77static void init_once(void *foo)
     78{
     79	struct minix_inode_info *ei = (struct minix_inode_info *) foo;
     80
     81	inode_init_once(&ei->vfs_inode);
     82}
     83
     84static int __init init_inodecache(void)
     85{
     86	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
     87					     sizeof(struct minix_inode_info),
     88					     0, (SLAB_RECLAIM_ACCOUNT|
     89						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
     90					     init_once);
     91	if (minix_inode_cachep == NULL)
     92		return -ENOMEM;
     93	return 0;
     94}
     95
     96static void destroy_inodecache(void)
     97{
     98	/*
     99	 * Make sure all delayed rcu free inodes are flushed before we
    100	 * destroy cache.
    101	 */
    102	rcu_barrier();
    103	kmem_cache_destroy(minix_inode_cachep);
    104}
    105
    106static const struct super_operations minix_sops = {
    107	.alloc_inode	= minix_alloc_inode,
    108	.free_inode	= minix_free_in_core_inode,
    109	.write_inode	= minix_write_inode,
    110	.evict_inode	= minix_evict_inode,
    111	.put_super	= minix_put_super,
    112	.statfs		= minix_statfs,
    113	.remount_fs	= minix_remount,
    114};
    115
    116static int minix_remount (struct super_block * sb, int * flags, char * data)
    117{
    118	struct minix_sb_info * sbi = minix_sb(sb);
    119	struct minix_super_block * ms;
    120
    121	sync_filesystem(sb);
    122	ms = sbi->s_ms;
    123	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
    124		return 0;
    125	if (*flags & SB_RDONLY) {
    126		if (ms->s_state & MINIX_VALID_FS ||
    127		    !(sbi->s_mount_state & MINIX_VALID_FS))
    128			return 0;
    129		/* Mounting a rw partition read-only. */
    130		if (sbi->s_version != MINIX_V3)
    131			ms->s_state = sbi->s_mount_state;
    132		mark_buffer_dirty(sbi->s_sbh);
    133	} else {
    134	  	/* Mount a partition which is read-only, read-write. */
    135		if (sbi->s_version != MINIX_V3) {
    136			sbi->s_mount_state = ms->s_state;
    137			ms->s_state &= ~MINIX_VALID_FS;
    138		} else {
    139			sbi->s_mount_state = MINIX_VALID_FS;
    140		}
    141		mark_buffer_dirty(sbi->s_sbh);
    142
    143		if (!(sbi->s_mount_state & MINIX_VALID_FS))
    144			printk("MINIX-fs warning: remounting unchecked fs, "
    145				"running fsck is recommended\n");
    146		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
    147			printk("MINIX-fs warning: remounting fs with errors, "
    148				"running fsck is recommended\n");
    149	}
    150	return 0;
    151}
    152
    153static bool minix_check_superblock(struct super_block *sb)
    154{
    155	struct minix_sb_info *sbi = minix_sb(sb);
    156
    157	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
    158		return false;
    159
    160	/*
    161	 * s_max_size must not exceed the block mapping limitation.  This check
    162	 * is only needed for V1 filesystems, since V2/V3 support an extra level
    163	 * of indirect blocks which places the limit well above U32_MAX.
    164	 */
    165	if (sbi->s_version == MINIX_V1 &&
    166	    sb->s_maxbytes > (7 + 512 + 512*512) * BLOCK_SIZE)
    167		return false;
    168
    169	return true;
    170}
    171
    172static int minix_fill_super(struct super_block *s, void *data, int silent)
    173{
    174	struct buffer_head *bh;
    175	struct buffer_head **map;
    176	struct minix_super_block *ms;
    177	struct minix3_super_block *m3s = NULL;
    178	unsigned long i, block;
    179	struct inode *root_inode;
    180	struct minix_sb_info *sbi;
    181	int ret = -EINVAL;
    182
    183	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
    184	if (!sbi)
    185		return -ENOMEM;
    186	s->s_fs_info = sbi;
    187
    188	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
    189	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
    190
    191	if (!sb_set_blocksize(s, BLOCK_SIZE))
    192		goto out_bad_hblock;
    193
    194	if (!(bh = sb_bread(s, 1)))
    195		goto out_bad_sb;
    196
    197	ms = (struct minix_super_block *) bh->b_data;
    198	sbi->s_ms = ms;
    199	sbi->s_sbh = bh;
    200	sbi->s_mount_state = ms->s_state;
    201	sbi->s_ninodes = ms->s_ninodes;
    202	sbi->s_nzones = ms->s_nzones;
    203	sbi->s_imap_blocks = ms->s_imap_blocks;
    204	sbi->s_zmap_blocks = ms->s_zmap_blocks;
    205	sbi->s_firstdatazone = ms->s_firstdatazone;
    206	sbi->s_log_zone_size = ms->s_log_zone_size;
    207	s->s_maxbytes = ms->s_max_size;
    208	s->s_magic = ms->s_magic;
    209	if (s->s_magic == MINIX_SUPER_MAGIC) {
    210		sbi->s_version = MINIX_V1;
    211		sbi->s_dirsize = 16;
    212		sbi->s_namelen = 14;
    213		s->s_max_links = MINIX_LINK_MAX;
    214	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
    215		sbi->s_version = MINIX_V1;
    216		sbi->s_dirsize = 32;
    217		sbi->s_namelen = 30;
    218		s->s_max_links = MINIX_LINK_MAX;
    219	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
    220		sbi->s_version = MINIX_V2;
    221		sbi->s_nzones = ms->s_zones;
    222		sbi->s_dirsize = 16;
    223		sbi->s_namelen = 14;
    224		s->s_max_links = MINIX2_LINK_MAX;
    225	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
    226		sbi->s_version = MINIX_V2;
    227		sbi->s_nzones = ms->s_zones;
    228		sbi->s_dirsize = 32;
    229		sbi->s_namelen = 30;
    230		s->s_max_links = MINIX2_LINK_MAX;
    231	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
    232		m3s = (struct minix3_super_block *) bh->b_data;
    233		s->s_magic = m3s->s_magic;
    234		sbi->s_imap_blocks = m3s->s_imap_blocks;
    235		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
    236		sbi->s_firstdatazone = m3s->s_firstdatazone;
    237		sbi->s_log_zone_size = m3s->s_log_zone_size;
    238		s->s_maxbytes = m3s->s_max_size;
    239		sbi->s_ninodes = m3s->s_ninodes;
    240		sbi->s_nzones = m3s->s_zones;
    241		sbi->s_dirsize = 64;
    242		sbi->s_namelen = 60;
    243		sbi->s_version = MINIX_V3;
    244		sbi->s_mount_state = MINIX_VALID_FS;
    245		sb_set_blocksize(s, m3s->s_blocksize);
    246		s->s_max_links = MINIX2_LINK_MAX;
    247	} else
    248		goto out_no_fs;
    249
    250	if (!minix_check_superblock(s))
    251		goto out_illegal_sb;
    252
    253	/*
    254	 * Allocate the buffer map to keep the superblock small.
    255	 */
    256	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
    257	map = kzalloc(i, GFP_KERNEL);
    258	if (!map)
    259		goto out_no_map;
    260	sbi->s_imap = &map[0];
    261	sbi->s_zmap = &map[sbi->s_imap_blocks];
    262
    263	block=2;
    264	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
    265		if (!(sbi->s_imap[i]=sb_bread(s, block)))
    266			goto out_no_bitmap;
    267		block++;
    268	}
    269	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
    270		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
    271			goto out_no_bitmap;
    272		block++;
    273	}
    274
    275	minix_set_bit(0,sbi->s_imap[0]->b_data);
    276	minix_set_bit(0,sbi->s_zmap[0]->b_data);
    277
    278	/* Apparently minix can create filesystems that allocate more blocks for
    279	 * the bitmaps than needed.  We simply ignore that, but verify it didn't
    280	 * create one with not enough blocks and bail out if so.
    281	 */
    282	block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
    283	if (sbi->s_imap_blocks < block) {
    284		printk("MINIX-fs: file system does not have enough "
    285				"imap blocks allocated.  Refusing to mount.\n");
    286		goto out_no_bitmap;
    287	}
    288
    289	block = minix_blocks_needed(
    290			(sbi->s_nzones - sbi->s_firstdatazone + 1),
    291			s->s_blocksize);
    292	if (sbi->s_zmap_blocks < block) {
    293		printk("MINIX-fs: file system does not have enough "
    294				"zmap blocks allocated.  Refusing to mount.\n");
    295		goto out_no_bitmap;
    296	}
    297
    298	/* set up enough so that it can read an inode */
    299	s->s_op = &minix_sops;
    300	s->s_time_min = 0;
    301	s->s_time_max = U32_MAX;
    302	root_inode = minix_iget(s, MINIX_ROOT_INO);
    303	if (IS_ERR(root_inode)) {
    304		ret = PTR_ERR(root_inode);
    305		goto out_no_root;
    306	}
    307
    308	ret = -ENOMEM;
    309	s->s_root = d_make_root(root_inode);
    310	if (!s->s_root)
    311		goto out_no_root;
    312
    313	if (!sb_rdonly(s)) {
    314		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
    315			ms->s_state &= ~MINIX_VALID_FS;
    316		mark_buffer_dirty(bh);
    317	}
    318	if (!(sbi->s_mount_state & MINIX_VALID_FS))
    319		printk("MINIX-fs: mounting unchecked file system, "
    320			"running fsck is recommended\n");
    321	else if (sbi->s_mount_state & MINIX_ERROR_FS)
    322		printk("MINIX-fs: mounting file system with errors, "
    323			"running fsck is recommended\n");
    324
    325	return 0;
    326
    327out_no_root:
    328	if (!silent)
    329		printk("MINIX-fs: get root inode failed\n");
    330	goto out_freemap;
    331
    332out_no_bitmap:
    333	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
    334out_freemap:
    335	for (i = 0; i < sbi->s_imap_blocks; i++)
    336		brelse(sbi->s_imap[i]);
    337	for (i = 0; i < sbi->s_zmap_blocks; i++)
    338		brelse(sbi->s_zmap[i]);
    339	kfree(sbi->s_imap);
    340	goto out_release;
    341
    342out_no_map:
    343	ret = -ENOMEM;
    344	if (!silent)
    345		printk("MINIX-fs: can't allocate map\n");
    346	goto out_release;
    347
    348out_illegal_sb:
    349	if (!silent)
    350		printk("MINIX-fs: bad superblock\n");
    351	goto out_release;
    352
    353out_no_fs:
    354	if (!silent)
    355		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
    356		       "on device %s.\n", s->s_id);
    357out_release:
    358	brelse(bh);
    359	goto out;
    360
    361out_bad_hblock:
    362	printk("MINIX-fs: blocksize too small for device\n");
    363	goto out;
    364
    365out_bad_sb:
    366	printk("MINIX-fs: unable to read superblock\n");
    367out:
    368	s->s_fs_info = NULL;
    369	kfree(sbi);
    370	return ret;
    371}
    372
    373static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
    374{
    375	struct super_block *sb = dentry->d_sb;
    376	struct minix_sb_info *sbi = minix_sb(sb);
    377	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
    378	buf->f_type = sb->s_magic;
    379	buf->f_bsize = sb->s_blocksize;
    380	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
    381	buf->f_bfree = minix_count_free_blocks(sb);
    382	buf->f_bavail = buf->f_bfree;
    383	buf->f_files = sbi->s_ninodes;
    384	buf->f_ffree = minix_count_free_inodes(sb);
    385	buf->f_namelen = sbi->s_namelen;
    386	buf->f_fsid = u64_to_fsid(id);
    387
    388	return 0;
    389}
    390
    391static int minix_get_block(struct inode *inode, sector_t block,
    392		    struct buffer_head *bh_result, int create)
    393{
    394	if (INODE_VERSION(inode) == MINIX_V1)
    395		return V1_minix_get_block(inode, block, bh_result, create);
    396	else
    397		return V2_minix_get_block(inode, block, bh_result, create);
    398}
    399
    400static int minix_writepage(struct page *page, struct writeback_control *wbc)
    401{
    402	return block_write_full_page(page, minix_get_block, wbc);
    403}
    404
    405static int minix_read_folio(struct file *file, struct folio *folio)
    406{
    407	return block_read_full_folio(folio, minix_get_block);
    408}
    409
    410int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
    411{
    412	return __block_write_begin(page, pos, len, minix_get_block);
    413}
    414
    415static void minix_write_failed(struct address_space *mapping, loff_t to)
    416{
    417	struct inode *inode = mapping->host;
    418
    419	if (to > inode->i_size) {
    420		truncate_pagecache(inode, inode->i_size);
    421		minix_truncate(inode);
    422	}
    423}
    424
    425static int minix_write_begin(struct file *file, struct address_space *mapping,
    426			loff_t pos, unsigned len,
    427			struct page **pagep, void **fsdata)
    428{
    429	int ret;
    430
    431	ret = block_write_begin(mapping, pos, len, pagep, minix_get_block);
    432	if (unlikely(ret))
    433		minix_write_failed(mapping, pos + len);
    434
    435	return ret;
    436}
    437
    438static sector_t minix_bmap(struct address_space *mapping, sector_t block)
    439{
    440	return generic_block_bmap(mapping,block,minix_get_block);
    441}
    442
    443static const struct address_space_operations minix_aops = {
    444	.dirty_folio	= block_dirty_folio,
    445	.invalidate_folio = block_invalidate_folio,
    446	.read_folio = minix_read_folio,
    447	.writepage = minix_writepage,
    448	.write_begin = minix_write_begin,
    449	.write_end = generic_write_end,
    450	.bmap = minix_bmap,
    451	.direct_IO = noop_direct_IO
    452};
    453
    454static const struct inode_operations minix_symlink_inode_operations = {
    455	.get_link	= page_get_link,
    456	.getattr	= minix_getattr,
    457};
    458
    459void minix_set_inode(struct inode *inode, dev_t rdev)
    460{
    461	if (S_ISREG(inode->i_mode)) {
    462		inode->i_op = &minix_file_inode_operations;
    463		inode->i_fop = &minix_file_operations;
    464		inode->i_mapping->a_ops = &minix_aops;
    465	} else if (S_ISDIR(inode->i_mode)) {
    466		inode->i_op = &minix_dir_inode_operations;
    467		inode->i_fop = &minix_dir_operations;
    468		inode->i_mapping->a_ops = &minix_aops;
    469	} else if (S_ISLNK(inode->i_mode)) {
    470		inode->i_op = &minix_symlink_inode_operations;
    471		inode_nohighmem(inode);
    472		inode->i_mapping->a_ops = &minix_aops;
    473	} else
    474		init_special_inode(inode, inode->i_mode, rdev);
    475}
    476
    477/*
    478 * The minix V1 function to read an inode.
    479 */
    480static struct inode *V1_minix_iget(struct inode *inode)
    481{
    482	struct buffer_head * bh;
    483	struct minix_inode * raw_inode;
    484	struct minix_inode_info *minix_inode = minix_i(inode);
    485	int i;
    486
    487	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
    488	if (!raw_inode) {
    489		iget_failed(inode);
    490		return ERR_PTR(-EIO);
    491	}
    492	if (raw_inode->i_nlinks == 0) {
    493		printk("MINIX-fs: deleted inode referenced: %lu\n",
    494		       inode->i_ino);
    495		brelse(bh);
    496		iget_failed(inode);
    497		return ERR_PTR(-ESTALE);
    498	}
    499	inode->i_mode = raw_inode->i_mode;
    500	i_uid_write(inode, raw_inode->i_uid);
    501	i_gid_write(inode, raw_inode->i_gid);
    502	set_nlink(inode, raw_inode->i_nlinks);
    503	inode->i_size = raw_inode->i_size;
    504	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
    505	inode->i_mtime.tv_nsec = 0;
    506	inode->i_atime.tv_nsec = 0;
    507	inode->i_ctime.tv_nsec = 0;
    508	inode->i_blocks = 0;
    509	for (i = 0; i < 9; i++)
    510		minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
    511	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
    512	brelse(bh);
    513	unlock_new_inode(inode);
    514	return inode;
    515}
    516
    517/*
    518 * The minix V2 function to read an inode.
    519 */
    520static struct inode *V2_minix_iget(struct inode *inode)
    521{
    522	struct buffer_head * bh;
    523	struct minix2_inode * raw_inode;
    524	struct minix_inode_info *minix_inode = minix_i(inode);
    525	int i;
    526
    527	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
    528	if (!raw_inode) {
    529		iget_failed(inode);
    530		return ERR_PTR(-EIO);
    531	}
    532	if (raw_inode->i_nlinks == 0) {
    533		printk("MINIX-fs: deleted inode referenced: %lu\n",
    534		       inode->i_ino);
    535		brelse(bh);
    536		iget_failed(inode);
    537		return ERR_PTR(-ESTALE);
    538	}
    539	inode->i_mode = raw_inode->i_mode;
    540	i_uid_write(inode, raw_inode->i_uid);
    541	i_gid_write(inode, raw_inode->i_gid);
    542	set_nlink(inode, raw_inode->i_nlinks);
    543	inode->i_size = raw_inode->i_size;
    544	inode->i_mtime.tv_sec = raw_inode->i_mtime;
    545	inode->i_atime.tv_sec = raw_inode->i_atime;
    546	inode->i_ctime.tv_sec = raw_inode->i_ctime;
    547	inode->i_mtime.tv_nsec = 0;
    548	inode->i_atime.tv_nsec = 0;
    549	inode->i_ctime.tv_nsec = 0;
    550	inode->i_blocks = 0;
    551	for (i = 0; i < 10; i++)
    552		minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
    553	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
    554	brelse(bh);
    555	unlock_new_inode(inode);
    556	return inode;
    557}
    558
    559/*
    560 * The global function to read an inode.
    561 */
    562struct inode *minix_iget(struct super_block *sb, unsigned long ino)
    563{
    564	struct inode *inode;
    565
    566	inode = iget_locked(sb, ino);
    567	if (!inode)
    568		return ERR_PTR(-ENOMEM);
    569	if (!(inode->i_state & I_NEW))
    570		return inode;
    571
    572	if (INODE_VERSION(inode) == MINIX_V1)
    573		return V1_minix_iget(inode);
    574	else
    575		return V2_minix_iget(inode);
    576}
    577
    578/*
    579 * The minix V1 function to synchronize an inode.
    580 */
    581static struct buffer_head * V1_minix_update_inode(struct inode * inode)
    582{
    583	struct buffer_head * bh;
    584	struct minix_inode * raw_inode;
    585	struct minix_inode_info *minix_inode = minix_i(inode);
    586	int i;
    587
    588	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
    589	if (!raw_inode)
    590		return NULL;
    591	raw_inode->i_mode = inode->i_mode;
    592	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
    593	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
    594	raw_inode->i_nlinks = inode->i_nlink;
    595	raw_inode->i_size = inode->i_size;
    596	raw_inode->i_time = inode->i_mtime.tv_sec;
    597	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
    598		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
    599	else for (i = 0; i < 9; i++)
    600		raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
    601	mark_buffer_dirty(bh);
    602	return bh;
    603}
    604
    605/*
    606 * The minix V2 function to synchronize an inode.
    607 */
    608static struct buffer_head * V2_minix_update_inode(struct inode * inode)
    609{
    610	struct buffer_head * bh;
    611	struct minix2_inode * raw_inode;
    612	struct minix_inode_info *minix_inode = minix_i(inode);
    613	int i;
    614
    615	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
    616	if (!raw_inode)
    617		return NULL;
    618	raw_inode->i_mode = inode->i_mode;
    619	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
    620	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
    621	raw_inode->i_nlinks = inode->i_nlink;
    622	raw_inode->i_size = inode->i_size;
    623	raw_inode->i_mtime = inode->i_mtime.tv_sec;
    624	raw_inode->i_atime = inode->i_atime.tv_sec;
    625	raw_inode->i_ctime = inode->i_ctime.tv_sec;
    626	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
    627		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
    628	else for (i = 0; i < 10; i++)
    629		raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
    630	mark_buffer_dirty(bh);
    631	return bh;
    632}
    633
    634static int minix_write_inode(struct inode *inode, struct writeback_control *wbc)
    635{
    636	int err = 0;
    637	struct buffer_head *bh;
    638
    639	if (INODE_VERSION(inode) == MINIX_V1)
    640		bh = V1_minix_update_inode(inode);
    641	else
    642		bh = V2_minix_update_inode(inode);
    643	if (!bh)
    644		return -EIO;
    645	if (wbc->sync_mode == WB_SYNC_ALL && buffer_dirty(bh)) {
    646		sync_dirty_buffer(bh);
    647		if (buffer_req(bh) && !buffer_uptodate(bh)) {
    648			printk("IO error syncing minix inode [%s:%08lx]\n",
    649				inode->i_sb->s_id, inode->i_ino);
    650			err = -EIO;
    651		}
    652	}
    653	brelse (bh);
    654	return err;
    655}
    656
    657int minix_getattr(struct user_namespace *mnt_userns, const struct path *path,
    658		  struct kstat *stat, u32 request_mask, unsigned int flags)
    659{
    660	struct super_block *sb = path->dentry->d_sb;
    661	struct inode *inode = d_inode(path->dentry);
    662
    663	generic_fillattr(&init_user_ns, inode, stat);
    664	if (INODE_VERSION(inode) == MINIX_V1)
    665		stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
    666	else
    667		stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
    668	stat->blksize = sb->s_blocksize;
    669	return 0;
    670}
    671
    672/*
    673 * The function that is called for file truncation.
    674 */
    675void minix_truncate(struct inode * inode)
    676{
    677	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
    678		return;
    679	if (INODE_VERSION(inode) == MINIX_V1)
    680		V1_minix_truncate(inode);
    681	else
    682		V2_minix_truncate(inode);
    683}
    684
    685static struct dentry *minix_mount(struct file_system_type *fs_type,
    686	int flags, const char *dev_name, void *data)
    687{
    688	return mount_bdev(fs_type, flags, dev_name, data, minix_fill_super);
    689}
    690
    691static struct file_system_type minix_fs_type = {
    692	.owner		= THIS_MODULE,
    693	.name		= "minix",
    694	.mount		= minix_mount,
    695	.kill_sb	= kill_block_super,
    696	.fs_flags	= FS_REQUIRES_DEV,
    697};
    698MODULE_ALIAS_FS("minix");
    699
    700static int __init init_minix_fs(void)
    701{
    702	int err = init_inodecache();
    703	if (err)
    704		goto out1;
    705	err = register_filesystem(&minix_fs_type);
    706	if (err)
    707		goto out;
    708	return 0;
    709out:
    710	destroy_inodecache();
    711out1:
    712	return err;
    713}
    714
    715static void __exit exit_minix_fs(void)
    716{
    717        unregister_filesystem(&minix_fs_type);
    718	destroy_inodecache();
    719}
    720
    721module_init(init_minix_fs)
    722module_exit(exit_minix_fs)
    723MODULE_LICENSE("GPL");
    724