[mirror_ubuntu-jammy-kernel.git] / fs / ext4 / block_validity.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ext4/block_validity.c
 *
 * Copyright (C) 2009
 * Theodore Ts'o (tytso@mit.edu)
 *
 * Track which blocks in the filesystem are metadata blocks that
 * should never be used as data blocks by files or directories.
 */

#include <linux/time.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include "ext4.h"

struct ext4_system_zone {
	struct rb_node	node;
	ext4_fsblk_t	start_blk;
	unsigned int	count;
};

static struct kmem_cache *ext4_system_zone_cachep;

int __init ext4_init_system_zone(void)
{
	ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
	if (ext4_system_zone_cachep == NULL)
		return -ENOMEM;
	return 0;
}

void ext4_exit_system_zone(void)
{
	kmem_cache_destroy(ext4_system_zone_cachep);
}

static inline int can_merge(struct ext4_system_zone *entry1,
		     struct ext4_system_zone *entry2)
{
	if ((entry1->start_blk + entry1->count) == entry2->start_blk)
		return 1;
	return 0;
}

/*
 * Mark a range of blocks as belonging to the "system zone" --- that
 * is, filesystem metadata blocks which should never be used by
 * inodes.
 */
static int add_system_zone(struct ext4_sb_info *sbi,
			   ext4_fsblk_t start_blk,
			   unsigned int count)
{
	struct ext4_system_zone *new_entry = NULL, *entry;
	struct rb_node **n = &sbi->system_blks.rb_node, *node;
	struct rb_node *parent = NULL, *new_node = NULL;

	while (*n) {
		parent = *n;
		entry = rb_entry(parent, struct ext4_system_zone, node);
		if (start_blk < entry->start_blk)
			n = &(*n)->rb_left;
		else if (start_blk >= (entry->start_blk + entry->count))
			n = &(*n)->rb_right;
		else {
			if (start_blk + count > (entry->start_blk +
						 entry->count))
				entry->count = (start_blk + count -
						entry->start_blk);
			new_node = *n;
			new_entry = rb_entry(new_node, struct ext4_system_zone,
					     node);
			break;
		}
	}

	if (!new_entry) {
		new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
					     GFP_KERNEL);
		if (!new_entry)
			return -ENOMEM;
		new_entry->start_blk = start_blk;
		new_entry->count = count;
		new_node = &new_entry->node;

		rb_link_node(new_node, parent, n);
		rb_insert_color(new_node, &sbi->system_blks);
	}

	/* Can we merge to the left? */
	node = rb_prev(new_node);
	if (node) {
		entry = rb_entry(node, struct ext4_system_zone, node);
		if (can_merge(entry, new_entry)) {
			new_entry->start_blk = entry->start_blk;
			new_entry->count += entry->count;
			rb_erase(node, &sbi->system_blks);
			kmem_cache_free(ext4_system_zone_cachep, entry);
		}
	}

	/* Can we merge to the right? */
	node = rb_next(new_node);
	if (node) {
		entry = rb_entry(node, struct ext4_system_zone, node);
		if (can_merge(new_entry, entry)) {
			new_entry->count += entry->count;
			rb_erase(node, &sbi->system_blks);
			kmem_cache_free(ext4_system_zone_cachep, entry);
		}
	}
	return 0;
}

static void debug_print_tree(struct ext4_sb_info *sbi)
{
	struct rb_node *node;
	struct ext4_system_zone *entry;
	int first = 1;

	printk(KERN_INFO "System zones: ");
	node = rb_first(&sbi->system_blks);
	while (node) {
		entry = rb_entry(node, struct ext4_system_zone, node);
		printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ",
		       entry->start_blk, entry->start_blk + entry->count - 1);
		first = 0;
		node = rb_next(node);
	}
	printk(KERN_CONT "\n");
}

static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino)
{
	struct inode *inode;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_map_blocks map;
	u32 i = 0, num;
	int err = 0, n;

	if ((ino < EXT4_ROOT_INO) ||
	    (ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
		return -EINVAL;
	inode = ext4_iget(sb, ino, EXT4_IGET_SPECIAL);
	if (IS_ERR(inode))
		return PTR_ERR(inode);
	num = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
	while (i < num) {
		map.m_lblk = i;
		map.m_len = num - i;
		n = ext4_map_blocks(NULL, inode, &map, 0);
		if (n < 0) {
			err = n;
			break;
		}
		if (n == 0) {
			i++;
		} else {
			if (!ext4_data_block_valid(sbi, map.m_pblk, n)) {
				ext4_error(sb, "blocks %llu-%llu from inode %u "
					   "overlap system zone", map.m_pblk,
					   map.m_pblk + map.m_len - 1, ino);
				err = -EFSCORRUPTED;
				break;
			}
			err = add_system_zone(sbi, map.m_pblk, n);
			if (err < 0)
				break;
			i += n;
		}
	}
	iput(inode);
	return err;
}

int ext4_setup_system_zone(struct super_block *sb)
{
	ext4_group_t ngroups = ext4_get_groups_count(sb);
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_group_desc *gdp;
	ext4_group_t i;
	int flex_size = ext4_flex_bg_size(sbi);
	int ret;

	if (!test_opt(sb, BLOCK_VALIDITY)) {
		if (sbi->system_blks.rb_node)
			ext4_release_system_zone(sb);
		return 0;
	}
	if (sbi->system_blks.rb_node)
		return 0;

	for (i=0; i < ngroups; i++) {
		cond_resched();
		if (ext4_bg_has_super(sb, i) &&
		    ((i < 5) || ((i % flex_size) == 0)))
			add_system_zone(sbi, ext4_group_first_block_no(sb, i),
					ext4_bg_num_gdb(sb, i) + 1);
		gdp = ext4_get_group_desc(sb, i, NULL);
		ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
		if (ret)
			return ret;
		ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
		if (ret)
			return ret;
		ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
				sbi->s_itb_per_group);
		if (ret)
			return ret;
	}
	if (ext4_has_feature_journal(sb) && sbi->s_es->s_journal_inum) {
		ret = ext4_protect_reserved_inode(sb,
				le32_to_cpu(sbi->s_es->s_journal_inum));
		if (ret)
			return ret;
	}

	if (test_opt(sb, DEBUG))
		debug_print_tree(sbi);
	return 0;
}

/* Called when the filesystem is unmounted */
void ext4_release_system_zone(struct super_block *sb)
{
	struct ext4_system_zone	*entry, *n;

	rbtree_postorder_for_each_entry_safe(entry, n,
			&EXT4_SB(sb)->system_blks, node)
		kmem_cache_free(ext4_system_zone_cachep, entry);

	EXT4_SB(sb)->system_blks = RB_ROOT;
}

/*
 * Returns 1 if the passed-in block region (start_blk,
 * start_blk+count) is valid; 0 if some part of the block region
 * overlaps with filesystem metadata blocks.
 */
int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
			  unsigned int count)
{
	struct ext4_system_zone *entry;
	struct rb_node *n = sbi->system_blks.rb_node;

	if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
	    (start_blk + count < start_blk) ||
	    (start_blk + count > ext4_blocks_count(sbi->s_es))) {
		sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
		return 0;
	}
	while (n) {
		entry = rb_entry(n, struct ext4_system_zone, node);
		if (start_blk + count - 1 < entry->start_blk)
			n = n->rb_left;
		else if (start_blk >= (entry->start_blk + entry->count))
			n = n->rb_right;
		else {
			sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
			return 0;
		}
	}
	return 1;
}

int ext4_check_blockref(const char *function, unsigned int line,
			struct inode *inode, __le32 *p, unsigned int max)
{
	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
	__le32 *bref = p;
	unsigned int blk;

	if (ext4_has_feature_journal(inode->i_sb) &&
	    (inode->i_ino ==
	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
		return 0;

	while (bref < p+max) {
		blk = le32_to_cpu(*bref++);
		if (blk &&
		    unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
						    blk, 1))) {
			es->s_last_error_block = cpu_to_le64(blk);
			ext4_error_inode(inode, function, line, blk,
					 "invalid block");
			return -EFSCORRUPTED;
		}
	}
	return 0;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
6fd058f7 TT	2	/*
	3	* linux/fs/ext4/block_validity.c
	4	*
	5	* Copyright (C) 2009
	6	* Theodore Ts'o (tytso@mit.edu)
	7	*
	8	* Track which blocks in the filesystem are metadata blocks that
	9	* should never be used as data blocks by files or directories.
	10	*/
	11
	12	#include <linux/time.h>
	13	#include <linux/fs.h>
	14	#include <linux/namei.h>
	15	#include <linux/quotaops.h>
	16	#include <linux/buffer_head.h>
6fd058f7 TT	17	#include <linux/swap.h>
6fd058f7 TT	18	#include <linux/pagemap.h>
6fd058f7	19	#include <linux/blkdev.h>
5a0e3ad6	20	#include <linux/slab.h>
6fd058f7 TT	21	#include "ext4.h"
	22
	23	struct ext4_system_zone {
	24	struct rb_node node;
	25	ext4_fsblk_t start_blk;
	26	unsigned int count;
	27	};
	28
	29	static struct kmem_cache *ext4_system_zone_cachep;
	30
5dabfc78	31	int __init ext4_init_system_zone(void)
6fd058f7	32	{
16828088	33	ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
6fd058f7 TT	34	if (ext4_system_zone_cachep == NULL)
	35	return -ENOMEM;
	36	return 0;
	37	}
	38
5dabfc78	39	void ext4_exit_system_zone(void)
6fd058f7 TT	40	{
	41	kmem_cache_destroy(ext4_system_zone_cachep);
	42	}
	43
	44	static inline int can_merge(struct ext4_system_zone *entry1,
	45	struct ext4_system_zone *entry2)
	46	{
	47	if ((entry1->start_blk + entry1->count) == entry2->start_blk)
	48	return 1;
	49	return 0;
	50	}
	51
	52	/*
	53	* Mark a range of blocks as belonging to the "system zone" --- that
	54	* is, filesystem metadata blocks which should never be used by
	55	* inodes.
	56	*/
	57	static int add_system_zone(struct ext4_sb_info *sbi,
	58	ext4_fsblk_t start_blk,
	59	unsigned int count)
	60	{
	61	struct ext4_system_zone new_entry = NULL, entry;
	62	struct rb_node *n = &sbi->system_blks.rb_node, node;
	63	struct rb_node parent = NULL, new_node = NULL;
	64
	65	while (*n) {
	66	parent = *n;
	67	entry = rb_entry(parent, struct ext4_system_zone, node);
	68	if (start_blk < entry->start_blk)
	69	n = &(*n)->rb_left;
	70	else if (start_blk >= (entry->start_blk + entry->count))
	71	n = &(*n)->rb_right;
	72	else {
60e6679e	73	if (start_blk + count > (entry->start_blk +
6fd058f7	74	entry->count))
60e6679e	75	entry->count = (start_blk + count -
6fd058f7 TT	76	entry->start_blk);
	77	new_node = *n;
	78	new_entry = rb_entry(new_node, struct ext4_system_zone,
	79	node);
	80	break;
	81	}
	82	}
	83
	84	if (!new_entry) {
	85	new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
	86	GFP_KERNEL);
	87	if (!new_entry)
	88	return -ENOMEM;
	89	new_entry->start_blk = start_blk;
	90	new_entry->count = count;
	91	new_node = &new_entry->node;
	92
	93	rb_link_node(new_node, parent, n);
	94	rb_insert_color(new_node, &sbi->system_blks);
	95	}
	96
	97	/* Can we merge to the left? */
	98	node = rb_prev(new_node);
	99	if (node) {
	100	entry = rb_entry(node, struct ext4_system_zone, node);
	101	if (can_merge(entry, new_entry)) {
	102	new_entry->start_blk = entry->start_blk;
	103	new_entry->count += entry->count;
	104	rb_erase(node, &sbi->system_blks);
	105	kmem_cache_free(ext4_system_zone_cachep, entry);
	106	}
	107	}
	108
	109	/* Can we merge to the right? */
	110	node = rb_next(new_node);
	111	if (node) {
	112	entry = rb_entry(node, struct ext4_system_zone, node);
	113	if (can_merge(new_entry, entry)) {
	114	new_entry->count += entry->count;
	115	rb_erase(node, &sbi->system_blks);
	116	kmem_cache_free(ext4_system_zone_cachep, entry);
	117	}
	118	}
	119	return 0;
	120	}
	121
	122	static void debug_print_tree(struct ext4_sb_info *sbi)
	123	{
	124	struct rb_node *node;
	125	struct ext4_system_zone *entry;
	126	int first = 1;
	127
	128	printk(KERN_INFO "System zones: ");
	129	node = rb_first(&sbi->system_blks);
	130	while (node) {
	131	entry = rb_entry(node, struct ext4_system_zone, node);
d74f3d25	132	printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ",
6fd058f7 TT	133	entry->start_blk, entry->start_blk + entry->count - 1);
	134	first = 0;
	135	node = rb_next(node);
	136	}
d74f3d25	137	printk(KERN_CONT "\n");
6fd058f7 TT	138	}
6fd058f7 TT	139
345c0dbf TT	140	static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino)
	141	{
	142	struct inode *inode;
	143	struct ext4_sb_info *sbi = EXT4_SB(sb);
	144	struct ext4_map_blocks map;
fbbbbd2f CIK	145	u32 i = 0, num;
fbbbbd2f CIK	146	int err = 0, n;
345c0dbf TT	147
	148	if ((ino < EXT4_ROOT_INO) \|\|
	149	(ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
	150	return -EINVAL;
	151	inode = ext4_iget(sb, ino, EXT4_IGET_SPECIAL);
	152	if (IS_ERR(inode))
	153	return PTR_ERR(inode);
	154	num = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
	155	while (i < num) {
	156	map.m_lblk = i;
	157	map.m_len = num - i;
	158	n = ext4_map_blocks(NULL, inode, &map, 0);
	159	if (n < 0) {
	160	err = n;
	161	break;
	162	}
	163	if (n == 0) {
	164	i++;
	165	} else {
	166	if (!ext4_data_block_valid(sbi, map.m_pblk, n)) {
	167	ext4_error(sb, "blocks %llu-%llu from inode %u "
	168	"overlap system zone", map.m_pblk,
	169	map.m_pblk + map.m_len - 1, ino);
	170	err = -EFSCORRUPTED;
	171	break;
	172	}
	173	err = add_system_zone(sbi, map.m_pblk, n);
	174	if (err < 0)
	175	break;
	176	i += n;
	177	}
	178	}
	179	iput(inode);
	180	return err;
	181	}
	182
6fd058f7 TT	183	int ext4_setup_system_zone(struct super_block *sb)
	184	{
	185	ext4_group_t ngroups = ext4_get_groups_count(sb);
	186	struct ext4_sb_info *sbi = EXT4_SB(sb);
	187	struct ext4_group_desc *gdp;
	188	ext4_group_t i;
	189	int flex_size = ext4_flex_bg_size(sbi);
	190	int ret;
	191
	192	if (!test_opt(sb, BLOCK_VALIDITY)) {
49598e04	193	if (sbi->system_blks.rb_node)
6fd058f7 TT	194	ext4_release_system_zone(sb);
	195	return 0;
	196	}
49598e04	197	if (sbi->system_blks.rb_node)
6fd058f7 TT	198	return 0;
	199
	200	for (i=0; i < ngroups; i++) {
4b99faa2	201	cond_resched();
6fd058f7 TT	202	if (ext4_bg_has_super(sb, i) &&
	203	((i < 5) \|\| ((i % flex_size) == 0)))
	204	add_system_zone(sbi, ext4_group_first_block_no(sb, i),
1032988c	205	ext4_bg_num_gdb(sb, i) + 1);
6fd058f7 TT	206	gdp = ext4_get_group_desc(sb, i, NULL);
	207	ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
	208	if (ret)
	209	return ret;
	210	ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
	211	if (ret)
	212	return ret;
	213	ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
	214	sbi->s_itb_per_group);
	215	if (ret)
	216	return ret;
	217	}
345c0dbf TT	218	if (ext4_has_feature_journal(sb) && sbi->s_es->s_journal_inum) {
	219	ret = ext4_protect_reserved_inode(sb,
	220	le32_to_cpu(sbi->s_es->s_journal_inum));
	221	if (ret)
	222	return ret;
	223	}
6fd058f7 TT	224
6fd058f7 TT	225	if (test_opt(sb, DEBUG))
49598e04	226	debug_print_tree(sbi);
6fd058f7 TT	227	return 0;
	228	}
	229
	230	/* Called when the filesystem is unmounted */
	231	void ext4_release_system_zone(struct super_block *sb)
	232	{
d1866bd0 CS	233	struct ext4_system_zone entry, n;
	234
	235	rbtree_postorder_for_each_entry_safe(entry, n,
	236	&EXT4_SB(sb)->system_blks, node)
6fd058f7	237	kmem_cache_free(ext4_system_zone_cachep, entry);
d1866bd0	238
64e290ec	239	EXT4_SB(sb)->system_blks = RB_ROOT;
6fd058f7 TT	240	}
	241
	242	/*
	243	* Returns 1 if the passed-in block region (start_blk,
	244	* start_blk+count) is valid; 0 if some part of the block region
	245	* overlaps with filesystem metadata blocks.
	246	*/
	247	int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
	248	unsigned int count)
	249	{
	250	struct ext4_system_zone *entry;
	251	struct rb_node *n = sbi->system_blks.rb_node;
	252
	253	if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) \|\|
1585d8d8	254	(start_blk + count < start_blk) \|\|
1c13d5c0 TT	255	(start_blk + count > ext4_blocks_count(sbi->s_es))) {
1c13d5c0 TT	256	sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
6fd058f7	257	return 0;
1c13d5c0	258	}
6fd058f7 TT	259	while (n) {
	260	entry = rb_entry(n, struct ext4_system_zone, node);
	261	if (start_blk + count - 1 < entry->start_blk)
	262	n = n->rb_left;
	263	else if (start_blk >= (entry->start_blk + entry->count))
	264	n = n->rb_right;
1c13d5c0 TT	265	else {
1c13d5c0 TT	266	sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
6fd058f7	267	return 0;
1c13d5c0	268	}
6fd058f7 TT	269	}
	270	return 1;
	271	}
	272
1f7d1e77 TT	273	int ext4_check_blockref(const char *function, unsigned int line,
	274	struct inode inode, __le32 p, unsigned int max)
	275	{
	276	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
	277	__le32 *bref = p;
	278	unsigned int blk;
	279
170417c8 TT	280	if (ext4_has_feature_journal(inode->i_sb) &&
	281	(inode->i_ino ==
	282	le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
	283	return 0;
	284
1f7d1e77 TT	285	while (bref < p+max) {
	286	blk = le32_to_cpu(*bref++);
	287	if (blk &&
	288	unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
	289	blk, 1))) {
	290	es->s_last_error_block = cpu_to_le64(blk);
	291	ext4_error_inode(inode, function, line, blk,
	292	"invalid block");
6a797d27	293	return -EFSCORRUPTED;
1f7d1e77 TT	294	}
	295	}
	296	return 0;
	297	}
dae1e52c	298