fs/btrfs/tree-checker.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) Qu Wenruo 2017.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public
  * License v2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public
  * License along with this program.
  */

 /*
  * The module is used to catch unexpected/corrupted tree block data.
  * Such behavior can be caused either by a fuzzed image or bugs.
  *
  * The objective is to do leaf/node validation checks when tree block is read
  * from disk, and check *every* possible member, so other code won't
  * need to checking them again.
  *
  * Due to the potential and unwanted damage, every checker needs to be
  * carefully reviewed otherwise so it does not prevent mount of valid images.
  */

 #include "ctree.h"
 #include "tree-checker.h"
 #include "disk-io.h"
 #include "compression.h"
 #include "hash.h"
 #include "volumes.h"

 #define CORRUPT(reason, eb, root, slot)					\
 	btrfs_crit(root->fs_info,					\
 		   "corrupt %s, %s: block=%llu, root=%llu, slot=%d",	\
 		   btrfs_header_level(eb) == 0 ? "leaf" : "node",	\
 		   reason, btrfs_header_bytenr(eb), root->objectid, slot)

 /*
  * Error message should follow the following format:
  * corrupt <type>: <identifier>, <reason>[, <bad_value>]
  *
  * @type:	leaf or node
  * @identifier:	the necessary info to locate the leaf/node.
  * 		It's recommened to decode key.objecitd/offset if it's
  * 		meaningful.
  * @reason:	describe the error
  * @bad_value:	optional, it's recommened to output bad value and its
  *		expected value (range).
  *
  * Since comma is used to separate the components, only space is allowed
  * inside each component.
  */

 /*
  * Append generic "corrupt leaf/node root=%llu block=%llu slot=%d: " to @fmt.
  * Allows callers to customize the output.
  */
 __printf(4, 5)
 static void generic_err(const struct btrfs_root *root,
 			const struct extent_buffer *eb, int slot,
 			const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;

 	va_start(args, fmt);

 	vaf.fmt = fmt;
 	vaf.va = &args;

 	btrfs_crit(root->fs_info,
 		"corrupt %s: root=%llu block=%llu slot=%d, %pV",
 		btrfs_header_level(eb) == 0 ? "leaf" : "node",
 		root->objectid, btrfs_header_bytenr(eb), slot, &vaf);
 	va_end(args);
 }

 static int check_extent_data_item(struct btrfs_root *root,
 				  struct extent_buffer *leaf,
 				  struct btrfs_key *key, int slot)
 {
 	struct btrfs_file_extent_item *fi;
 	u32 sectorsize = root->sectorsize;
 	u32 item_size = btrfs_item_size_nr(leaf, slot);

 	if (!IS_ALIGNED(key->offset, sectorsize)) {
 		CORRUPT("unaligned key offset for file extent",
 			leaf, root, slot);
 		return -EUCLEAN;
 	}

 	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);

 	if (btrfs_file_extent_type(leaf, fi) > BTRFS_FILE_EXTENT_TYPES) {
 		CORRUPT("invalid file extent type", leaf, root, slot);
 		return -EUCLEAN;
 	}

 	/*
 	 * Support for new compression/encrption must introduce incompat flag,
 	 * and must be caught in open_ctree().
 	 */
 	if (btrfs_file_extent_compression(leaf, fi) > BTRFS_COMPRESS_TYPES) {
 		CORRUPT("invalid file extent compression", leaf, root, slot);
 		return -EUCLEAN;
 	}
 	if (btrfs_file_extent_encryption(leaf, fi)) {
 		CORRUPT("invalid file extent encryption", leaf, root, slot);
 		return -EUCLEAN;
 	}
 	if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
 		/* Inline extent must have 0 as key offset */
 		if (key->offset) {
 			CORRUPT("inline extent has non-zero key offset",
 				leaf, root, slot);
 			return -EUCLEAN;
 		}

 		/* Compressed inline extent has no on-disk size, skip it */
 		if (btrfs_file_extent_compression(leaf, fi) !=
 		    BTRFS_COMPRESS_NONE)
 			return 0;

 		/* Uncompressed inline extent size must match item size */
 		if (item_size != BTRFS_FILE_EXTENT_INLINE_DATA_START +
 		    btrfs_file_extent_ram_bytes(leaf, fi)) {
 			CORRUPT("plaintext inline extent has invalid size",
 				leaf, root, slot);
 			return -EUCLEAN;
 		}
 		return 0;
 	}

 	/* Regular or preallocated extent has fixed item size */
 	if (item_size != sizeof(*fi)) {
 		CORRUPT(
 		"regluar or preallocated extent data item size is invalid",
 			leaf, root, slot);
 		return -EUCLEAN;
 	}
 	if (!IS_ALIGNED(btrfs_file_extent_ram_bytes(leaf, fi), sectorsize) ||
 	    !IS_ALIGNED(btrfs_file_extent_disk_bytenr(leaf, fi), sectorsize) ||
 	    !IS_ALIGNED(btrfs_file_extent_disk_num_bytes(leaf, fi), sectorsize) ||
 	    !IS_ALIGNED(btrfs_file_extent_offset(leaf, fi), sectorsize) ||
 	    !IS_ALIGNED(btrfs_file_extent_num_bytes(leaf, fi), sectorsize)) {
 		CORRUPT(
 		"regular or preallocated extent data item has unaligned value",
 			leaf, root, slot);
 		return -EUCLEAN;
 	}

 	return 0;
 }

 static int check_csum_item(struct btrfs_root *root, struct extent_buffer *leaf,
 			   struct btrfs_key *key, int slot)
 {
 	u32 sectorsize = root->sectorsize;
 	u32 csumsize = btrfs_super_csum_size(root->fs_info->super_copy);

 	if (key->objectid != BTRFS_EXTENT_CSUM_OBJECTID) {
 		CORRUPT("invalid objectid for csum item", leaf, root, slot);
 		return -EUCLEAN;
 	}
 	if (!IS_ALIGNED(key->offset, sectorsize)) {
 		CORRUPT("unaligned key offset for csum item", leaf, root, slot);
 		return -EUCLEAN;
 	}
 	if (!IS_ALIGNED(btrfs_item_size_nr(leaf, slot), csumsize)) {
 		CORRUPT("unaligned csum item size", leaf, root, slot);
 		return -EUCLEAN;
 	}
 	return 0;
 }

 /*
  * Customized reported for dir_item, only important new info is key->objectid,
  * which represents inode number
  */
 __printf(4, 5)
 static void dir_item_err(const struct btrfs_root *root,
 			 const struct extent_buffer *eb, int slot,
 			 const char *fmt, ...)
 {
 	struct btrfs_key key;
 	struct va_format vaf;
 	va_list args;

 	btrfs_item_key_to_cpu(eb, &key, slot);
 	va_start(args, fmt);

 	vaf.fmt = fmt;
 	vaf.va = &args;

 	btrfs_crit(root->fs_info,
 	"corrupt %s: root=%llu block=%llu slot=%d ino=%llu, %pV",
 		btrfs_header_level(eb) == 0 ? "leaf" : "node", root->objectid,
 		btrfs_header_bytenr(eb), slot, key.objectid, &vaf);
 	va_end(args);
 }

 static int check_dir_item(struct btrfs_root *root,
 			  struct extent_buffer *leaf,
 			  struct btrfs_key *key, int slot)
 {
 	struct btrfs_dir_item *di;
 	u32 item_size = btrfs_item_size_nr(leaf, slot);
 	u32 cur = 0;

 	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
 	while (cur < item_size) {
 		u32 name_len;
 		u32 data_len;
 		u32 max_name_len;
 		u32 total_size;
 		u32 name_hash;
 		u8 dir_type;

 		/* header itself should not cross item boundary */
 		if (cur + sizeof(*di) > item_size) {
 			dir_item_err(root, leaf, slot,
 		"dir item header crosses item boundary, have %zu boundary %u",
 				cur + sizeof(*di), item_size);
 			return -EUCLEAN;
 		}

 		/* dir type check */
 		dir_type = btrfs_dir_type(leaf, di);
 		if (dir_type >= BTRFS_FT_MAX) {
 			dir_item_err(root, leaf, slot,
 			"invalid dir item type, have %u expect [0, %u)",
 				dir_type, BTRFS_FT_MAX);
 			return -EUCLEAN;
 		}

 		if (key->type == BTRFS_XATTR_ITEM_KEY &&
 		    dir_type != BTRFS_FT_XATTR) {
 			dir_item_err(root, leaf, slot,
 		"invalid dir item type for XATTR key, have %u expect %u",
 				dir_type, BTRFS_FT_XATTR);
 			return -EUCLEAN;
 		}
 		if (dir_type == BTRFS_FT_XATTR &&
 		    key->type != BTRFS_XATTR_ITEM_KEY) {
 			dir_item_err(root, leaf, slot,
 			"xattr dir type found for non-XATTR key");
 			return -EUCLEAN;
 		}
 		if (dir_type == BTRFS_FT_XATTR)
 			max_name_len = XATTR_NAME_MAX;
 		else
 			max_name_len = BTRFS_NAME_LEN;

 		/* Name/data length check */
 		name_len = btrfs_dir_name_len(leaf, di);
 		data_len = btrfs_dir_data_len(leaf, di);
 		if (name_len > max_name_len) {
 			dir_item_err(root, leaf, slot,
 			"dir item name len too long, have %u max %u",
 				name_len, max_name_len);
 			return -EUCLEAN;
 		}
 		if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root)) {
 			dir_item_err(root, leaf, slot,
 			"dir item name and data len too long, have %u max %u",
 				name_len + data_len,
 				BTRFS_MAX_XATTR_SIZE(root));
 			return -EUCLEAN;
 		}

 		if (data_len && dir_type != BTRFS_FT_XATTR) {
 			dir_item_err(root, leaf, slot,
 			"dir item with invalid data len, have %u expect 0",
 				data_len);
 			return -EUCLEAN;
 		}

 		total_size = sizeof(*di) + name_len + data_len;

 		/* header and name/data should not cross item boundary */
 		if (cur + total_size > item_size) {
 			dir_item_err(root, leaf, slot,
 		"dir item data crosses item boundary, have %u boundary %u",
 				cur + total_size, item_size);
 			return -EUCLEAN;
 		}

 		/*
 		 * Special check for XATTR/DIR_ITEM, as key->offset is name
 		 * hash, should match its name
 		 */
 		if (key->type == BTRFS_DIR_ITEM_KEY ||
 		    key->type == BTRFS_XATTR_ITEM_KEY) {
 			char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)];

 			read_extent_buffer(leaf, namebuf,
 					(unsigned long)(di + 1), name_len);
 			name_hash = btrfs_name_hash(namebuf, name_len);
 			if (key->offset != name_hash) {
 				dir_item_err(root, leaf, slot,
 		"name hash mismatch with key, have 0x%016x expect 0x%016llx",
 					name_hash, key->offset);
 				return -EUCLEAN;
 			}
 		}
 		cur += total_size;
 		di = (struct btrfs_dir_item *)((void *)di + total_size);
 	}
 	return 0;
 }

 __printf(4, 5)
 __cold
 static void block_group_err(const struct btrfs_fs_info *fs_info,
 			    const struct extent_buffer *eb, int slot,
 			    const char *fmt, ...)
 {
 	struct btrfs_key key;
 	struct va_format vaf;
 	va_list args;

 	btrfs_item_key_to_cpu(eb, &key, slot);
 	va_start(args, fmt);

 	vaf.fmt = fmt;
 	vaf.va = &args;

 	btrfs_crit(fs_info,
 	"corrupt %s: root=%llu block=%llu slot=%d bg_start=%llu bg_len=%llu, %pV",
 		btrfs_header_level(eb) == 0 ? "leaf" : "node",
 		btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot,
 		key.objectid, key.offset, &vaf);
 	va_end(args);
 }

 static int check_block_group_item(struct btrfs_fs_info *fs_info,
 				  struct extent_buffer *leaf,
 				  struct btrfs_key *key, int slot)
 {
 	struct btrfs_block_group_item bgi;
 	u32 item_size = btrfs_item_size_nr(leaf, slot);
 	u64 flags;
 	u64 type;

 	/*
 	 * Here we don't really care about alignment since extent allocator can
 	 * handle it.  We care more about the size, as if one block group is
 	 * larger than maximum size, it's must be some obvious corruption.
 	 */
 	if (key->offset > BTRFS_MAX_DATA_CHUNK_SIZE || key->offset == 0) {
 		block_group_err(fs_info, leaf, slot,
 			"invalid block group size, have %llu expect (0, %llu]",
 				key->offset, BTRFS_MAX_DATA_CHUNK_SIZE);
 		return -EUCLEAN;
 	}

 	if (item_size != sizeof(bgi)) {
 		block_group_err(fs_info, leaf, slot,
 			"invalid item size, have %u expect %zu",
 				item_size, sizeof(bgi));
 		return -EUCLEAN;
 	}

 	read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
 			   sizeof(bgi));
 	if (btrfs_block_group_chunk_objectid(&bgi) !=
 	    BTRFS_FIRST_CHUNK_TREE_OBJECTID) {
 		block_group_err(fs_info, leaf, slot,
 		"invalid block group chunk objectid, have %llu expect %llu",
 				btrfs_block_group_chunk_objectid(&bgi),
 				BTRFS_FIRST_CHUNK_TREE_OBJECTID);
 		return -EUCLEAN;
 	}

 	if (btrfs_block_group_used(&bgi) > key->offset) {
 		block_group_err(fs_info, leaf, slot,
 			"invalid block group used, have %llu expect [0, %llu)",
 				btrfs_block_group_used(&bgi), key->offset);
 		return -EUCLEAN;
 	}

 	flags = btrfs_block_group_flags(&bgi);
 	if (hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) > 1) {
 		block_group_err(fs_info, leaf, slot,
 "invalid profile flags, have 0x%llx (%lu bits set) expect no more than 1 bit set",
 			flags & BTRFS_BLOCK_GROUP_PROFILE_MASK,
 			hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK));
 		return -EUCLEAN;
 	}

 	type = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
 	if (type != BTRFS_BLOCK_GROUP_DATA &&
 	    type != BTRFS_BLOCK_GROUP_METADATA &&
 	    type != BTRFS_BLOCK_GROUP_SYSTEM &&
 	    type != (BTRFS_BLOCK_GROUP_METADATA |
 			   BTRFS_BLOCK_GROUP_DATA)) {
 		block_group_err(fs_info, leaf, slot,
 "invalid type, have 0x%llx (%lu bits set) expect either 0x%llx, 0x%llx, 0x%llx or 0x%llx",
 			type, hweight64(type),
 			BTRFS_BLOCK_GROUP_DATA, BTRFS_BLOCK_GROUP_METADATA,
 			BTRFS_BLOCK_GROUP_SYSTEM,
 			BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA);
 		return -EUCLEAN;
 	}
 	return 0;
 }

 /*
  * Common point to switch the item-specific validation.
  */
 static int check_leaf_item(struct btrfs_root *root,
 			   struct extent_buffer *leaf,
 			   struct btrfs_key *key, int slot)
 {
 	int ret = 0;

 	switch (key->type) {
 	case BTRFS_EXTENT_DATA_KEY:
 		ret = check_extent_data_item(root, leaf, key, slot);
 		break;
 	case BTRFS_EXTENT_CSUM_KEY:
 		ret = check_csum_item(root, leaf, key, slot);
 		break;
 	case BTRFS_DIR_ITEM_KEY:
 	case BTRFS_DIR_INDEX_KEY:
 	case BTRFS_XATTR_ITEM_KEY:
 		ret = check_dir_item(root, leaf, key, slot);
 		break;
 	case BTRFS_BLOCK_GROUP_ITEM_KEY:
 		ret = check_block_group_item(root->fs_info, leaf, key, slot);
 		break;
 	}
 	return ret;
 }

 static int check_leaf(struct btrfs_root *root, struct extent_buffer *leaf,
 		      bool check_item_data)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	/* No valid key type is 0, so all key should be larger than this key */
 	struct btrfs_key prev_key = {0, 0, 0};
 	struct btrfs_key key;
 	u32 nritems = btrfs_header_nritems(leaf);
 	int slot;

 	if (btrfs_header_level(leaf) != 0) {
 		generic_err(root, leaf, 0,
 			"invalid level for leaf, have %d expect 0",
 			btrfs_header_level(leaf));
 		return -EUCLEAN;
 	}

 	/*
 	 * Extent buffers from a relocation tree have a owner field that
 	 * corresponds to the subvolume tree they are based on. So just from an
 	 * extent buffer alone we can not find out what is the id of the
 	 * corresponding subvolume tree, so we can not figure out if the extent
 	 * buffer corresponds to the root of the relocation tree or not. So
 	 * skip this check for relocation trees.
 	 */
 	if (nritems == 0 && !btrfs_header_flag(leaf, BTRFS_HEADER_FLAG_RELOC)) {
 		u64 owner = btrfs_header_owner(leaf);
 		struct btrfs_root *check_root;

 		/* These trees must never be empty */
 		if (owner == BTRFS_ROOT_TREE_OBJECTID ||
 		    owner == BTRFS_CHUNK_TREE_OBJECTID ||
 		    owner == BTRFS_EXTENT_TREE_OBJECTID ||
 		    owner == BTRFS_DEV_TREE_OBJECTID ||
 		    owner == BTRFS_FS_TREE_OBJECTID ||
 		    owner == BTRFS_DATA_RELOC_TREE_OBJECTID) {
 			generic_err(root, leaf, 0,
 			"invalid root, root %llu must never be empty",
 				    owner);
 			return -EUCLEAN;
 		}
 		key.objectid = owner;
 		key.type = BTRFS_ROOT_ITEM_KEY;
 		key.offset = (u64)-1;

 		check_root = btrfs_get_fs_root(fs_info, &key, false);
 		/*
 		 * The only reason we also check NULL here is that during
 		 * open_ctree() some roots has not yet been set up.
 		 */
 		if (!IS_ERR_OR_NULL(check_root)) {
 			struct extent_buffer *eb;

 			eb = btrfs_root_node(check_root);
 			/* if leaf is the root, then it's fine */
 			if (leaf != eb) {
 				CORRUPT("non-root leaf's nritems is 0",
 					leaf, check_root, 0);
 				free_extent_buffer(eb);
 				return -EUCLEAN;
 			}
 			free_extent_buffer(eb);
 		}
 		return 0;
 	}

 	if (nritems == 0)
 		return 0;

 	/*
 	 * Check the following things to make sure this is a good leaf, and
 	 * leaf users won't need to bother with similar sanity checks:
 	 *
 	 * 1) key ordering
 	 * 2) item offset and size
 	 *    No overlap, no hole, all inside the leaf.
 	 * 3) item content
 	 *    If possible, do comprehensive sanity check.
 	 *    NOTE: All checks must only rely on the item data itself.
 	 */
 	for (slot = 0; slot < nritems; slot++) {
 		u32 item_end_expected;
 		int ret;

 		btrfs_item_key_to_cpu(leaf, &key, slot);

 		/* Make sure the keys are in the right order */
 		if (btrfs_comp_cpu_keys(&prev_key, &key) >= 0) {
 			CORRUPT("bad key order", leaf, root, slot);
 			return -EUCLEAN;
 		}

 		/*
 		 * Make sure the offset and ends are right, remember that the
 		 * item data starts at the end of the leaf and grows towards the
 		 * front.
 		 */
 		if (slot == 0)
 			item_end_expected = BTRFS_LEAF_DATA_SIZE(root);
 		else
 			item_end_expected = btrfs_item_offset_nr(leaf,
 								 slot - 1);
 		if (btrfs_item_end_nr(leaf, slot) != item_end_expected) {
 			CORRUPT("slot offset bad", leaf, root, slot);
 			return -EUCLEAN;
 		}

 		/*
 		 * Check to make sure that we don't point outside of the leaf,
 		 * just in case all the items are consistent to each other, but
 		 * all point outside of the leaf.
 		 */
 		if (btrfs_item_end_nr(leaf, slot) >
 		    BTRFS_LEAF_DATA_SIZE(root)) {
 			CORRUPT("slot end outside of leaf", leaf, root, slot);
 			return -EUCLEAN;
 		}

 		/* Also check if the item pointer overlaps with btrfs item. */
 		if (btrfs_item_nr_offset(slot) + sizeof(struct btrfs_item) >
 		    btrfs_item_ptr_offset(leaf, slot)) {
 			CORRUPT("slot overlap with its data", leaf, root, slot);
 			return -EUCLEAN;
 		}

 		if (check_item_data) {
 			/*
 			 * Check if the item size and content meet other
 			 * criteria
 			 */
 			ret = check_leaf_item(root, leaf, &key, slot);
 			if (ret < 0)
 				return ret;
 		}

 		prev_key.objectid = key.objectid;
 		prev_key.type = key.type;
 		prev_key.offset = key.offset;
 	}

 	return 0;
 }

 int btrfs_check_leaf_full(struct btrfs_root *root, struct extent_buffer *leaf)
 {
 	return check_leaf(root, leaf, true);
 }

 int btrfs_check_leaf_relaxed(struct btrfs_root *root,
 			     struct extent_buffer *leaf)
 {
 	return check_leaf(root, leaf, false);
 }

 int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node)
 {
 	unsigned long nr = btrfs_header_nritems(node);
 	struct btrfs_key key, next_key;
 	int slot;
 	int level = btrfs_header_level(node);
 	u64 bytenr;
 	int ret = 0;

 	if (level <= 0 || level >= BTRFS_MAX_LEVEL) {
 		generic_err(root, node, 0,
 			"invalid level for node, have %d expect [1, %d]",
 			level, BTRFS_MAX_LEVEL - 1);
 		return -EUCLEAN;
 	}
 	if (nr == 0 || nr > BTRFS_NODEPTRS_PER_BLOCK(root)) {
 		btrfs_crit(root->fs_info,
 "corrupt node: root=%llu block=%llu, nritems too %s, have %lu expect range [1,%u]",
 			   root->objectid, node->start,
 			   nr == 0 ? "small" : "large", nr,
 			   BTRFS_NODEPTRS_PER_BLOCK(root));
 		return -EUCLEAN;
 	}

 	for (slot = 0; slot < nr - 1; slot++) {
 		bytenr = btrfs_node_blockptr(node, slot);
 		btrfs_node_key_to_cpu(node, &key, slot);
 		btrfs_node_key_to_cpu(node, &next_key, slot + 1);

 		if (!bytenr) {
 			generic_err(root, node, slot,
 				"invalid NULL node pointer");
 			ret = -EUCLEAN;
 			goto out;
 		}
 		if (!IS_ALIGNED(bytenr, root->sectorsize)) {
 			generic_err(root, node, slot,
 			"unaligned pointer, have %llu should be aligned to %u",
 				bytenr, root->sectorsize);
 			ret = -EUCLEAN;
 			goto out;
 		}

 		if (btrfs_comp_cpu_keys(&key, &next_key) >= 0) {
 			generic_err(root, node, slot,
 	"bad key order, current (%llu %u %llu) next (%llu %u %llu)",
 				key.objectid, key.type, key.offset,
 				next_key.objectid, next_key.type,
 				next_key.offset);
 			ret = -EUCLEAN;
 			goto out;
 		}
 	}
 out:
 	return ret;
 }
	/*
	* Copyright (C) Qu Wenruo 2017. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public
	* License v2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public
	* License along with this program.
	*/

	/*
	* The module is used to catch unexpected/corrupted tree block data.
	* Such behavior can be caused either by a fuzzed image or bugs.
	*
	* The objective is to do leaf/node validation checks when tree block is read
	* from disk, and check every possible member, so other code won't
	* need to checking them again.
	*
	* Due to the potential and unwanted damage, every checker needs to be
	* carefully reviewed otherwise so it does not prevent mount of valid images.
	*/

	#include "ctree.h"
	#include "tree-checker.h"
	#include "disk-io.h"
	#include "compression.h"
	#include "hash.h"
	#include "volumes.h"

	#define CORRUPT(reason, eb, root, slot) \
	btrfs_crit(root->fs_info, \
	"corrupt %s, %s: block=%llu, root=%llu, slot=%d", \
	btrfs_header_level(eb) == 0 ? "leaf" : "node", \
	reason, btrfs_header_bytenr(eb), root->objectid, slot)

	/*
	* Error message should follow the following format:
	* corrupt <type>: <identifier>, <reason>[, <bad_value>]
	*
	* @type: leaf or node
	* @identifier: the necessary info to locate the leaf/node.
	* It's recommened to decode key.objecitd/offset if it's
	* meaningful.
	* @reason: describe the error
	* @bad_value: optional, it's recommened to output bad value and its
	* expected value (range).
	*
	* Since comma is used to separate the components, only space is allowed
	* inside each component.
	*/

	/*
	* Append generic "corrupt leaf/node root=%llu block=%llu slot=%d: " to @fmt.
	* Allows callers to customize the output.
	*/
	__printf(4, 5)
	static void generic_err(const struct btrfs_root *root,
	const struct extent_buffer *eb, int slot,
	const char *fmt, ...)
	{
	struct va_format vaf;
	va_list args;

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	btrfs_crit(root->fs_info,
	"corrupt %s: root=%llu block=%llu slot=%d, %pV",
	btrfs_header_level(eb) == 0 ? "leaf" : "node",
	root->objectid, btrfs_header_bytenr(eb), slot, &vaf);
	va_end(args);
	}

	static int check_extent_data_item(struct btrfs_root *root,
	struct extent_buffer *leaf,
	struct btrfs_key *key, int slot)
	{
	struct btrfs_file_extent_item *fi;
	u32 sectorsize = root->sectorsize;
	u32 item_size = btrfs_item_size_nr(leaf, slot);

	if (!IS_ALIGNED(key->offset, sectorsize)) {
	CORRUPT("unaligned key offset for file extent",
	leaf, root, slot);
	return -EUCLEAN;
	}

	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);

	if (btrfs_file_extent_type(leaf, fi) > BTRFS_FILE_EXTENT_TYPES) {
	CORRUPT("invalid file extent type", leaf, root, slot);
	return -EUCLEAN;
	}

	/*
	* Support for new compression/encrption must introduce incompat flag,
	* and must be caught in open_ctree().
	*/
	if (btrfs_file_extent_compression(leaf, fi) > BTRFS_COMPRESS_TYPES) {
	CORRUPT("invalid file extent compression", leaf, root, slot);
	return -EUCLEAN;
	}
	if (btrfs_file_extent_encryption(leaf, fi)) {
	CORRUPT("invalid file extent encryption", leaf, root, slot);
	return -EUCLEAN;
	}
	if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
	/* Inline extent must have 0 as key offset */
	if (key->offset) {
	CORRUPT("inline extent has non-zero key offset",
	leaf, root, slot);
	return -EUCLEAN;
	}

	/* Compressed inline extent has no on-disk size, skip it */
	if (btrfs_file_extent_compression(leaf, fi) !=
	BTRFS_COMPRESS_NONE)
	return 0;

	/* Uncompressed inline extent size must match item size */
	if (item_size != BTRFS_FILE_EXTENT_INLINE_DATA_START +
	btrfs_file_extent_ram_bytes(leaf, fi)) {
	CORRUPT("plaintext inline extent has invalid size",
	leaf, root, slot);
	return -EUCLEAN;
	}
	return 0;
	}

	/* Regular or preallocated extent has fixed item size */
	if (item_size != sizeof(*fi)) {
	CORRUPT(
	"regluar or preallocated extent data item size is invalid",
	leaf, root, slot);
	return -EUCLEAN;
	}
	if (!IS_ALIGNED(btrfs_file_extent_ram_bytes(leaf, fi), sectorsize) \|\|
	!IS_ALIGNED(btrfs_file_extent_disk_bytenr(leaf, fi), sectorsize) \|\|
	!IS_ALIGNED(btrfs_file_extent_disk_num_bytes(leaf, fi), sectorsize) \|\|
	!IS_ALIGNED(btrfs_file_extent_offset(leaf, fi), sectorsize) \|\|
	!IS_ALIGNED(btrfs_file_extent_num_bytes(leaf, fi), sectorsize)) {
	CORRUPT(
	"regular or preallocated extent data item has unaligned value",
	leaf, root, slot);
	return -EUCLEAN;
	}

	return 0;
	}

	static int check_csum_item(struct btrfs_root root, struct extent_buffer leaf,
	struct btrfs_key *key, int slot)
	{
	u32 sectorsize = root->sectorsize;
	u32 csumsize = btrfs_super_csum_size(root->fs_info->super_copy);

	if (key->objectid != BTRFS_EXTENT_CSUM_OBJECTID) {
	CORRUPT("invalid objectid for csum item", leaf, root, slot);
	return -EUCLEAN;
	}
	if (!IS_ALIGNED(key->offset, sectorsize)) {
	CORRUPT("unaligned key offset for csum item", leaf, root, slot);
	return -EUCLEAN;
	}
	if (!IS_ALIGNED(btrfs_item_size_nr(leaf, slot), csumsize)) {
	CORRUPT("unaligned csum item size", leaf, root, slot);
	return -EUCLEAN;
	}
	return 0;
	}

	/*
	* Customized reported for dir_item, only important new info is key->objectid,
	* which represents inode number
	*/
	__printf(4, 5)
	static void dir_item_err(const struct btrfs_root *root,
	const struct extent_buffer *eb, int slot,
	const char *fmt, ...)
	{
	struct btrfs_key key;
	struct va_format vaf;
	va_list args;

	btrfs_item_key_to_cpu(eb, &key, slot);
	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	btrfs_crit(root->fs_info,
	"corrupt %s: root=%llu block=%llu slot=%d ino=%llu, %pV",
	btrfs_header_level(eb) == 0 ? "leaf" : "node", root->objectid,
	btrfs_header_bytenr(eb), slot, key.objectid, &vaf);
	va_end(args);
	}

	static int check_dir_item(struct btrfs_root *root,
	struct extent_buffer *leaf,
	struct btrfs_key *key, int slot)
	{
	struct btrfs_dir_item *di;
	u32 item_size = btrfs_item_size_nr(leaf, slot);
	u32 cur = 0;

	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
	while (cur < item_size) {
	u32 name_len;
	u32 data_len;
	u32 max_name_len;
	u32 total_size;
	u32 name_hash;
	u8 dir_type;

	/* header itself should not cross item boundary */
	if (cur + sizeof(*di) > item_size) {
	dir_item_err(root, leaf, slot,
	"dir item header crosses item boundary, have %zu boundary %u",
	cur + sizeof(*di), item_size);
	return -EUCLEAN;
	}

	/* dir type check */
	dir_type = btrfs_dir_type(leaf, di);
	if (dir_type >= BTRFS_FT_MAX) {
	dir_item_err(root, leaf, slot,
	"invalid dir item type, have %u expect [0, %u)",
	dir_type, BTRFS_FT_MAX);
	return -EUCLEAN;
	}

	if (key->type == BTRFS_XATTR_ITEM_KEY &&
	dir_type != BTRFS_FT_XATTR) {
	dir_item_err(root, leaf, slot,
	"invalid dir item type for XATTR key, have %u expect %u",
	dir_type, BTRFS_FT_XATTR);
	return -EUCLEAN;
	}
	if (dir_type == BTRFS_FT_XATTR &&
	key->type != BTRFS_XATTR_ITEM_KEY) {
	dir_item_err(root, leaf, slot,
	"xattr dir type found for non-XATTR key");
	return -EUCLEAN;
	}
	if (dir_type == BTRFS_FT_XATTR)
	max_name_len = XATTR_NAME_MAX;
	else
	max_name_len = BTRFS_NAME_LEN;

	/* Name/data length check */
	name_len = btrfs_dir_name_len(leaf, di);
	data_len = btrfs_dir_data_len(leaf, di);
	if (name_len > max_name_len) {
	dir_item_err(root, leaf, slot,
	"dir item name len too long, have %u max %u",
	name_len, max_name_len);
	return -EUCLEAN;
	}
	if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root)) {
	dir_item_err(root, leaf, slot,
	"dir item name and data len too long, have %u max %u",
	name_len + data_len,
	BTRFS_MAX_XATTR_SIZE(root));
	return -EUCLEAN;
	}

	if (data_len && dir_type != BTRFS_FT_XATTR) {
	dir_item_err(root, leaf, slot,
	"dir item with invalid data len, have %u expect 0",
	data_len);
	return -EUCLEAN;
	}

	total_size = sizeof(*di) + name_len + data_len;

	/* header and name/data should not cross item boundary */
	if (cur + total_size > item_size) {
	dir_item_err(root, leaf, slot,
	"dir item data crosses item boundary, have %u boundary %u",
	cur + total_size, item_size);
	return -EUCLEAN;
	}

	/*
	* Special check for XATTR/DIR_ITEM, as key->offset is name
	* hash, should match its name
	*/
	if (key->type == BTRFS_DIR_ITEM_KEY \|\|
	key->type == BTRFS_XATTR_ITEM_KEY) {
	char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)];

	read_extent_buffer(leaf, namebuf,
	(unsigned long)(di + 1), name_len);
	name_hash = btrfs_name_hash(namebuf, name_len);
	if (key->offset != name_hash) {
	dir_item_err(root, leaf, slot,
	"name hash mismatch with key, have 0x%016x expect 0x%016llx",
	name_hash, key->offset);
	return -EUCLEAN;
	}
	}
	cur += total_size;
	di = (struct btrfs_dir_item )((void )di + total_size);
	}
	return 0;
	}

	__printf(4, 5)
	__cold
	static void block_group_err(const struct btrfs_fs_info *fs_info,
	const struct extent_buffer *eb, int slot,
	const char *fmt, ...)
	{
	struct btrfs_key key;
	struct va_format vaf;
	va_list args;

	btrfs_item_key_to_cpu(eb, &key, slot);
	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	btrfs_crit(fs_info,
	"corrupt %s: root=%llu block=%llu slot=%d bg_start=%llu bg_len=%llu, %pV",
	btrfs_header_level(eb) == 0 ? "leaf" : "node",
	btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot,
	key.objectid, key.offset, &vaf);
	va_end(args);
	}

	static int check_block_group_item(struct btrfs_fs_info *fs_info,
	struct extent_buffer *leaf,
	struct btrfs_key *key, int slot)
	{
	struct btrfs_block_group_item bgi;
	u32 item_size = btrfs_item_size_nr(leaf, slot);
	u64 flags;
	u64 type;

	/*
	* Here we don't really care about alignment since extent allocator can
	* handle it. We care more about the size, as if one block group is
	* larger than maximum size, it's must be some obvious corruption.
	*/
	if (key->offset > BTRFS_MAX_DATA_CHUNK_SIZE \|\| key->offset == 0) {
	block_group_err(fs_info, leaf, slot,
	"invalid block group size, have %llu expect (0, %llu]",
	key->offset, BTRFS_MAX_DATA_CHUNK_SIZE);
	return -EUCLEAN;
	}

	if (item_size != sizeof(bgi)) {
	block_group_err(fs_info, leaf, slot,
	"invalid item size, have %u expect %zu",
	item_size, sizeof(bgi));
	return -EUCLEAN;
	}

	read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
	sizeof(bgi));
	if (btrfs_block_group_chunk_objectid(&bgi) !=
	BTRFS_FIRST_CHUNK_TREE_OBJECTID) {
	block_group_err(fs_info, leaf, slot,
	"invalid block group chunk objectid, have %llu expect %llu",
	btrfs_block_group_chunk_objectid(&bgi),
	BTRFS_FIRST_CHUNK_TREE_OBJECTID);
	return -EUCLEAN;
	}

	if (btrfs_block_group_used(&bgi) > key->offset) {
	block_group_err(fs_info, leaf, slot,
	"invalid block group used, have %llu expect [0, %llu)",
	btrfs_block_group_used(&bgi), key->offset);
	return -EUCLEAN;
	}

	flags = btrfs_block_group_flags(&bgi);
	if (hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) > 1) {
	block_group_err(fs_info, leaf, slot,
	"invalid profile flags, have 0x%llx (%lu bits set) expect no more than 1 bit set",
	flags & BTRFS_BLOCK_GROUP_PROFILE_MASK,
	hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK));
	return -EUCLEAN;
	}

	type = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
	if (type != BTRFS_BLOCK_GROUP_DATA &&
	type != BTRFS_BLOCK_GROUP_METADATA &&
	type != BTRFS_BLOCK_GROUP_SYSTEM &&
	type != (BTRFS_BLOCK_GROUP_METADATA \|
	BTRFS_BLOCK_GROUP_DATA)) {
	block_group_err(fs_info, leaf, slot,
	"invalid type, have 0x%llx (%lu bits set) expect either 0x%llx, 0x%llx, 0x%llx or 0x%llx",
	type, hweight64(type),
	BTRFS_BLOCK_GROUP_DATA, BTRFS_BLOCK_GROUP_METADATA,
	BTRFS_BLOCK_GROUP_SYSTEM,
	BTRFS_BLOCK_GROUP_METADATA \| BTRFS_BLOCK_GROUP_DATA);
	return -EUCLEAN;
	}
	return 0;
	}

	/*
	* Common point to switch the item-specific validation.
	*/
	static int check_leaf_item(struct btrfs_root *root,
	struct extent_buffer *leaf,
	struct btrfs_key *key, int slot)
	{
	int ret = 0;

	switch (key->type) {
	case BTRFS_EXTENT_DATA_KEY:
	ret = check_extent_data_item(root, leaf, key, slot);
	break;
	case BTRFS_EXTENT_CSUM_KEY:
	ret = check_csum_item(root, leaf, key, slot);
	break;
	case BTRFS_DIR_ITEM_KEY:
	case BTRFS_DIR_INDEX_KEY:
	case BTRFS_XATTR_ITEM_KEY:
	ret = check_dir_item(root, leaf, key, slot);
	break;
	case BTRFS_BLOCK_GROUP_ITEM_KEY:
	ret = check_block_group_item(root->fs_info, leaf, key, slot);
	break;
	}
	return ret;
	}

	static int check_leaf(struct btrfs_root root, struct extent_buffer leaf,
	bool check_item_data)
	{
	struct btrfs_fs_info *fs_info = root->fs_info;
	/* No valid key type is 0, so all key should be larger than this key */
	struct btrfs_key prev_key = {0, 0, 0};
	struct btrfs_key key;
	u32 nritems = btrfs_header_nritems(leaf);
	int slot;

	if (btrfs_header_level(leaf) != 0) {
	generic_err(root, leaf, 0,
	"invalid level for leaf, have %d expect 0",
	btrfs_header_level(leaf));
	return -EUCLEAN;
	}

	/*
	* Extent buffers from a relocation tree have a owner field that
	* corresponds to the subvolume tree they are based on. So just from an
	* extent buffer alone we can not find out what is the id of the
	* corresponding subvolume tree, so we can not figure out if the extent
	* buffer corresponds to the root of the relocation tree or not. So
	* skip this check for relocation trees.
	*/
	if (nritems == 0 && !btrfs_header_flag(leaf, BTRFS_HEADER_FLAG_RELOC)) {
	u64 owner = btrfs_header_owner(leaf);
	struct btrfs_root *check_root;

	/* These trees must never be empty */
	if (owner == BTRFS_ROOT_TREE_OBJECTID \|\|
	owner == BTRFS_CHUNK_TREE_OBJECTID \|\|
	owner == BTRFS_EXTENT_TREE_OBJECTID \|\|
	owner == BTRFS_DEV_TREE_OBJECTID \|\|
	owner == BTRFS_FS_TREE_OBJECTID \|\|
	owner == BTRFS_DATA_RELOC_TREE_OBJECTID) {
	generic_err(root, leaf, 0,
	"invalid root, root %llu must never be empty",
	owner);
	return -EUCLEAN;
	}
	key.objectid = owner;
	key.type = BTRFS_ROOT_ITEM_KEY;
	key.offset = (u64)-1;

	check_root = btrfs_get_fs_root(fs_info, &key, false);
	/*
	* The only reason we also check NULL here is that during
	* open_ctree() some roots has not yet been set up.
	*/
	if (!IS_ERR_OR_NULL(check_root)) {
	struct extent_buffer *eb;

	eb = btrfs_root_node(check_root);
	/* if leaf is the root, then it's fine */
	if (leaf != eb) {
	CORRUPT("non-root leaf's nritems is 0",
	leaf, check_root, 0);
	free_extent_buffer(eb);
	return -EUCLEAN;
	}
	free_extent_buffer(eb);
	}
	return 0;
	}

	if (nritems == 0)
	return 0;

	/*
	* Check the following things to make sure this is a good leaf, and
	* leaf users won't need to bother with similar sanity checks:
	*
	* 1) key ordering
	* 2) item offset and size
	* No overlap, no hole, all inside the leaf.
	* 3) item content
	* If possible, do comprehensive sanity check.
	* NOTE: All checks must only rely on the item data itself.
	*/
	for (slot = 0; slot < nritems; slot++) {
	u32 item_end_expected;
	int ret;

	btrfs_item_key_to_cpu(leaf, &key, slot);

	/* Make sure the keys are in the right order */
	if (btrfs_comp_cpu_keys(&prev_key, &key) >= 0) {
	CORRUPT("bad key order", leaf, root, slot);
	return -EUCLEAN;
	}

	/*
	* Make sure the offset and ends are right, remember that the
	* item data starts at the end of the leaf and grows towards the
	* front.
	*/
	if (slot == 0)
	item_end_expected = BTRFS_LEAF_DATA_SIZE(root);
	else
	item_end_expected = btrfs_item_offset_nr(leaf,
	slot - 1);
	if (btrfs_item_end_nr(leaf, slot) != item_end_expected) {
	CORRUPT("slot offset bad", leaf, root, slot);
	return -EUCLEAN;
	}

	/*
	* Check to make sure that we don't point outside of the leaf,
	* just in case all the items are consistent to each other, but
	* all point outside of the leaf.
	*/
	if (btrfs_item_end_nr(leaf, slot) >
	BTRFS_LEAF_DATA_SIZE(root)) {
	CORRUPT("slot end outside of leaf", leaf, root, slot);
	return -EUCLEAN;
	}

	/* Also check if the item pointer overlaps with btrfs item. */
	if (btrfs_item_nr_offset(slot) + sizeof(struct btrfs_item) >
	btrfs_item_ptr_offset(leaf, slot)) {
	CORRUPT("slot overlap with its data", leaf, root, slot);
	return -EUCLEAN;
	}

	if (check_item_data) {
	/*
	* Check if the item size and content meet other
	* criteria
	*/
	ret = check_leaf_item(root, leaf, &key, slot);
	if (ret < 0)
	return ret;
	}

	prev_key.objectid = key.objectid;
	prev_key.type = key.type;
	prev_key.offset = key.offset;
	}

	return 0;
	}

	int btrfs_check_leaf_full(struct btrfs_root root, struct extent_buffer leaf)
	{
	return check_leaf(root, leaf, true);
	}

	int btrfs_check_leaf_relaxed(struct btrfs_root *root,
	struct extent_buffer *leaf)
	{
	return check_leaf(root, leaf, false);
	}

	int btrfs_check_node(struct btrfs_root root, struct extent_buffer node)
	{
	unsigned long nr = btrfs_header_nritems(node);
	struct btrfs_key key, next_key;
	int slot;
	int level = btrfs_header_level(node);
	u64 bytenr;
	int ret = 0;

	if (level <= 0 \|\| level >= BTRFS_MAX_LEVEL) {
	generic_err(root, node, 0,
	"invalid level for node, have %d expect [1, %d]",
	level, BTRFS_MAX_LEVEL - 1);
	return -EUCLEAN;
	}
	if (nr == 0 \|\| nr > BTRFS_NODEPTRS_PER_BLOCK(root)) {
	btrfs_crit(root->fs_info,
	"corrupt node: root=%llu block=%llu, nritems too %s, have %lu expect range [1,%u]",
	root->objectid, node->start,
	nr == 0 ? "small" : "large", nr,
	BTRFS_NODEPTRS_PER_BLOCK(root));
	return -EUCLEAN;
	}

	for (slot = 0; slot < nr - 1; slot++) {
	bytenr = btrfs_node_blockptr(node, slot);
	btrfs_node_key_to_cpu(node, &key, slot);
	btrfs_node_key_to_cpu(node, &next_key, slot + 1);

	if (!bytenr) {
	generic_err(root, node, slot,
	"invalid NULL node pointer");
	ret = -EUCLEAN;
	goto out;
	}
	if (!IS_ALIGNED(bytenr, root->sectorsize)) {
	generic_err(root, node, slot,
	"unaligned pointer, have %llu should be aligned to %u",
	bytenr, root->sectorsize);
	ret = -EUCLEAN;
	goto out;
	}

	if (btrfs_comp_cpu_keys(&key, &next_key) >= 0) {
	generic_err(root, node, slot,
	"bad key order, current (%llu %u %llu) next (%llu %u %llu)",
	key.objectid, key.type, key.offset,
	next_key.objectid, next_key.type,
	next_key.offset);
	ret = -EUCLEAN;
	goto out;
	}
	}
	out:
	return ret;
	}