// SPDX-License-Identifier: GPL-2.0

  /*
   * Copyright (C) Qu Wenruo 2017.  All rights reserved.

   */
  
  /*
   * 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 <linux/types.h>
  #include <linux/stddef.h>
  #include <linux/error-injection.h>

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

  #include "volumes.h"

  #include "misc.h"

  /*
   * 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 recommended to decode key.objecitd/offset if it's

   * 		meaningful.
   * @reason:	describe the error

   * @bad_value:	optional, it's recommended 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(3, 4)

  __cold

  static void generic_err(const struct extent_buffer *eb, int slot,

  			const char *fmt, ...)
  {

  	const struct btrfs_fs_info *fs_info = eb->fs_info;

  	struct va_format vaf;
  	va_list args;
  
  	va_start(args, fmt);
  
  	vaf.fmt = fmt;
  	vaf.va = &args;

  	btrfs_crit(fs_info,

  		"corrupt %s: root=%llu block=%llu slot=%d, %pV",
  		btrfs_header_level(eb) == 0 ? "leaf" : "node",

  		btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot, &vaf);

  	va_end(args);
  }

  /*
   * Customized reporter for extent data item, since its key objectid and
   * offset has its own meaning.
   */

  __printf(3, 4)

  __cold

  static void file_extent_err(const struct extent_buffer *eb, int slot,

  			    const char *fmt, ...)
  {

  	const struct btrfs_fs_info *fs_info = eb->fs_info;

  	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 ino=%llu file_offset=%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);
  }
  
  /*
   * Return 0 if the btrfs_file_extent_##name is aligned to @alignment
   * Else return 1
   */

  #define CHECK_FE_ALIGNED(leaf, slot, fi, name, alignment)		      \

  ({									      \
  	if (!IS_ALIGNED(btrfs_file_extent_##name((leaf), (fi)), (alignment))) \

  		file_extent_err((leaf), (slot),				      \

  	"invalid %s for file extent, have %llu, should be aligned to %u",     \
  			(#name), btrfs_file_extent_##name((leaf), (fi)),      \
  			(alignment));					      \
  	(!IS_ALIGNED(btrfs_file_extent_##name((leaf), (fi)), (alignment)));   \
  })

  static u64 file_extent_end(struct extent_buffer *leaf,
  			   struct btrfs_key *key,
  			   struct btrfs_file_extent_item *extent)
  {
  	u64 end;
  	u64 len;
  
  	if (btrfs_file_extent_type(leaf, extent) == BTRFS_FILE_EXTENT_INLINE) {
  		len = btrfs_file_extent_ram_bytes(leaf, extent);
  		end = ALIGN(key->offset + len, leaf->fs_info->sectorsize);
  	} else {
  		len = btrfs_file_extent_num_bytes(leaf, extent);
  		end = key->offset + len;
  	}
  	return end;
  }

  /*
   * Customized report for dir_item, the only new important information is
   * key->objectid, which represents inode number
   */
  __printf(3, 4)
  __cold
  static void dir_item_err(const struct extent_buffer *eb, int slot,
  			 const char *fmt, ...)
  {
  	const struct btrfs_fs_info *fs_info = eb->fs_info;
  	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 ino=%llu, %pV",
  		btrfs_header_level(eb) == 0 ? "leaf" : "node",
  		btrfs_header_owner(eb), btrfs_header_bytenr(eb), slot,
  		key.objectid, &vaf);
  	va_end(args);
  }
  
  /*
   * This functions checks prev_key->objectid, to ensure current key and prev_key
   * share the same objectid as inode number.
   *
   * This is to detect missing INODE_ITEM in subvolume trees.
   *
   * Return true if everything is OK or we don't need to check.
   * Return false if anything is wrong.
   */
  static bool check_prev_ino(struct extent_buffer *leaf,
  			   struct btrfs_key *key, int slot,
  			   struct btrfs_key *prev_key)
  {
  	/* No prev key, skip check */
  	if (slot == 0)
  		return true;
  
  	/* Only these key->types needs to be checked */
  	ASSERT(key->type == BTRFS_XATTR_ITEM_KEY ||
  	       key->type == BTRFS_INODE_REF_KEY ||
  	       key->type == BTRFS_DIR_INDEX_KEY ||
  	       key->type == BTRFS_DIR_ITEM_KEY ||
  	       key->type == BTRFS_EXTENT_DATA_KEY);
  
  	/*
  	 * Only subvolume trees along with their reloc trees need this check.
  	 * Things like log tree doesn't follow this ino requirement.
  	 */
  	if (!is_fstree(btrfs_header_owner(leaf)))
  		return true;
  
  	if (key->objectid == prev_key->objectid)
  		return true;
  
  	/* Error found */
  	dir_item_err(leaf, slot,
  		"invalid previous key objectid, have %llu expect %llu",
  		prev_key->objectid, key->objectid);
  	return false;
  }

  static int check_extent_data_item(struct extent_buffer *leaf,

  				  struct btrfs_key *key, int slot,
  				  struct btrfs_key *prev_key)

  {

  	struct btrfs_fs_info *fs_info = leaf->fs_info;

  	struct btrfs_file_extent_item *fi;

  	u32 sectorsize = fs_info->sectorsize;

  	u32 item_size = btrfs_item_size_nr(leaf, slot);

  	u64 extent_end;

  
  	if (!IS_ALIGNED(key->offset, sectorsize)) {

  		file_extent_err(leaf, slot,

  "unaligned file_offset for file extent, have %llu should be aligned to %u",
  			key->offset, sectorsize);

  		return -EUCLEAN;
  	}

  	/*
  	 * Previous key must have the same key->objectid (ino).
  	 * It can be XATTR_ITEM, INODE_ITEM or just another EXTENT_DATA.
  	 * But if objectids mismatch, it means we have a missing
  	 * INODE_ITEM.
  	 */

  	if (!check_prev_ino(leaf, key, slot, prev_key))

  		return -EUCLEAN;

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

  	/*
  	 * Make sure the item contains at least inline header, so the file
  	 * extent type is not some garbage.
  	 */
  	if (item_size < BTRFS_FILE_EXTENT_INLINE_DATA_START) {
  		file_extent_err(leaf, slot,

  				"invalid item size, have %u expect [%zu, %u)",

  				item_size, BTRFS_FILE_EXTENT_INLINE_DATA_START,
  				SZ_4K);
  		return -EUCLEAN;
  	}

  	if (btrfs_file_extent_type(leaf, fi) >= BTRFS_NR_FILE_EXTENT_TYPES) {

  		file_extent_err(leaf, slot,

  		"invalid type for file extent, have %u expect range [0, %u]",
  			btrfs_file_extent_type(leaf, fi),

  			BTRFS_NR_FILE_EXTENT_TYPES - 1);

  		return -EUCLEAN;
  	}
  
  	/*

  	 * Support for new compression/encryption must introduce incompat flag,

  	 * and must be caught in open_ctree().
  	 */

  	if (btrfs_file_extent_compression(leaf, fi) >= BTRFS_NR_COMPRESS_TYPES) {

  		file_extent_err(leaf, slot,

  	"invalid compression for file extent, have %u expect range [0, %u]",
  			btrfs_file_extent_compression(leaf, fi),

  			BTRFS_NR_COMPRESS_TYPES - 1);

  		return -EUCLEAN;
  	}
  	if (btrfs_file_extent_encryption(leaf, fi)) {

  		file_extent_err(leaf, slot,

  			"invalid encryption for file extent, have %u expect 0",
  			btrfs_file_extent_encryption(leaf, fi));

  		return -EUCLEAN;
  	}
  	if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
  		/* Inline extent must have 0 as key offset */
  		if (key->offset) {

  			file_extent_err(leaf, slot,

  		"invalid file_offset for inline file extent, have %llu expect 0",
  				key->offset);

  			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)) {

  			file_extent_err(leaf, slot,

  	"invalid ram_bytes for uncompressed inline extent, have %u expect %llu",
  				item_size, BTRFS_FILE_EXTENT_INLINE_DATA_START +
  				btrfs_file_extent_ram_bytes(leaf, fi));

  			return -EUCLEAN;
  		}
  		return 0;
  	}
  
  	/* Regular or preallocated extent has fixed item size */
  	if (item_size != sizeof(*fi)) {

  		file_extent_err(leaf, slot,

  	"invalid item size for reg/prealloc file extent, have %u expect %zu",

  			item_size, sizeof(*fi));

  		return -EUCLEAN;
  	}

  	if (CHECK_FE_ALIGNED(leaf, slot, fi, ram_bytes, sectorsize) ||
  	    CHECK_FE_ALIGNED(leaf, slot, fi, disk_bytenr, sectorsize) ||
  	    CHECK_FE_ALIGNED(leaf, slot, fi, disk_num_bytes, sectorsize) ||
  	    CHECK_FE_ALIGNED(leaf, slot, fi, offset, sectorsize) ||
  	    CHECK_FE_ALIGNED(leaf, slot, fi, num_bytes, sectorsize))

  		return -EUCLEAN;

  	/* Catch extent end overflow */
  	if (check_add_overflow(btrfs_file_extent_num_bytes(leaf, fi),
  			       key->offset, &extent_end)) {
  		file_extent_err(leaf, slot,
  	"extent end overflow, have file offset %llu extent num bytes %llu",
  				key->offset,
  				btrfs_file_extent_num_bytes(leaf, fi));
  		return -EUCLEAN;
  	}

  	/*
  	 * Check that no two consecutive file extent items, in the same leaf,
  	 * present ranges that overlap each other.
  	 */
  	if (slot > 0 &&
  	    prev_key->objectid == key->objectid &&
  	    prev_key->type == BTRFS_EXTENT_DATA_KEY) {
  		struct btrfs_file_extent_item *prev_fi;
  		u64 prev_end;
  
  		prev_fi = btrfs_item_ptr(leaf, slot - 1,
  					 struct btrfs_file_extent_item);
  		prev_end = file_extent_end(leaf, prev_key, prev_fi);
  		if (prev_end > key->offset) {
  			file_extent_err(leaf, slot - 1,
  "file extent end range (%llu) goes beyond start offset (%llu) of the next file extent",
  					prev_end, key->offset);
  			return -EUCLEAN;
  		}
  	}

  	return 0;
  }

  static int check_csum_item(struct extent_buffer *leaf, struct btrfs_key *key,

  			   int slot, struct btrfs_key *prev_key)

  {

  	struct btrfs_fs_info *fs_info = leaf->fs_info;

  	u32 sectorsize = fs_info->sectorsize;
  	u32 csumsize = btrfs_super_csum_size(fs_info->super_copy);

  
  	if (key->objectid != BTRFS_EXTENT_CSUM_OBJECTID) {

  		generic_err(leaf, slot,

  		"invalid key objectid for csum item, have %llu expect %llu",
  			key->objectid, BTRFS_EXTENT_CSUM_OBJECTID);

  		return -EUCLEAN;
  	}
  	if (!IS_ALIGNED(key->offset, sectorsize)) {

  		generic_err(leaf, slot,

  	"unaligned key offset for csum item, have %llu should be aligned to %u",
  			key->offset, sectorsize);

  		return -EUCLEAN;
  	}
  	if (!IS_ALIGNED(btrfs_item_size_nr(leaf, slot), csumsize)) {

  		generic_err(leaf, slot,

  	"unaligned item size for csum item, have %u should be aligned to %u",
  			btrfs_item_size_nr(leaf, slot), csumsize);

  		return -EUCLEAN;
  	}

  	if (slot > 0 && prev_key->type == BTRFS_EXTENT_CSUM_KEY) {
  		u64 prev_csum_end;
  		u32 prev_item_size;
  
  		prev_item_size = btrfs_item_size_nr(leaf, slot - 1);
  		prev_csum_end = (prev_item_size / csumsize) * sectorsize;
  		prev_csum_end += prev_key->offset;
  		if (prev_csum_end > key->offset) {
  			generic_err(leaf, slot - 1,
  "csum end range (%llu) goes beyond the start range (%llu) of the next csum item",
  				    prev_csum_end, key->offset);
  			return -EUCLEAN;
  		}
  	}

  	return 0;
  }

  /* Inode item error output has the same format as dir_item_err() */
  #define inode_item_err(eb, slot, fmt, ...)			\
  	dir_item_err(eb, slot, fmt, __VA_ARGS__)
  
  static int check_inode_key(struct extent_buffer *leaf, struct btrfs_key *key,
  			   int slot)
  {
  	struct btrfs_key item_key;
  	bool is_inode_item;
  
  	btrfs_item_key_to_cpu(leaf, &item_key, slot);
  	is_inode_item = (item_key.type == BTRFS_INODE_ITEM_KEY);
  
  	/* For XATTR_ITEM, location key should be all 0 */
  	if (item_key.type == BTRFS_XATTR_ITEM_KEY) {
  		if (key->type != 0 || key->objectid != 0 || key->offset != 0)
  			return -EUCLEAN;
  		return 0;
  	}
  
  	if ((key->objectid < BTRFS_FIRST_FREE_OBJECTID ||
  	     key->objectid > BTRFS_LAST_FREE_OBJECTID) &&
  	    key->objectid != BTRFS_ROOT_TREE_DIR_OBJECTID &&
  	    key->objectid != BTRFS_FREE_INO_OBJECTID) {
  		if (is_inode_item) {
  			generic_err(leaf, slot,
  	"invalid key objectid: has %llu expect %llu or [%llu, %llu] or %llu",
  				key->objectid, BTRFS_ROOT_TREE_DIR_OBJECTID,
  				BTRFS_FIRST_FREE_OBJECTID,
  				BTRFS_LAST_FREE_OBJECTID,
  				BTRFS_FREE_INO_OBJECTID);
  		} else {
  			dir_item_err(leaf, slot,
  "invalid location key objectid: has %llu expect %llu or [%llu, %llu] or %llu",
  				key->objectid, BTRFS_ROOT_TREE_DIR_OBJECTID,
  				BTRFS_FIRST_FREE_OBJECTID,
  				BTRFS_LAST_FREE_OBJECTID,
  				BTRFS_FREE_INO_OBJECTID);
  		}
  		return -EUCLEAN;
  	}
  	if (key->offset != 0) {
  		if (is_inode_item)
  			inode_item_err(leaf, slot,
  				       "invalid key offset: has %llu expect 0",
  				       key->offset);
  		else
  			dir_item_err(leaf, slot,
  				"invalid location key offset:has %llu expect 0",
  				key->offset);
  		return -EUCLEAN;
  	}
  	return 0;
  }

  static int check_root_key(struct extent_buffer *leaf, struct btrfs_key *key,
  			  int slot)
  {
  	struct btrfs_key item_key;
  	bool is_root_item;
  
  	btrfs_item_key_to_cpu(leaf, &item_key, slot);
  	is_root_item = (item_key.type == BTRFS_ROOT_ITEM_KEY);
  
  	/* No such tree id */
  	if (key->objectid == 0) {
  		if (is_root_item)
  			generic_err(leaf, slot, "invalid root id 0");
  		else
  			dir_item_err(leaf, slot,
  				     "invalid location key root id 0");
  		return -EUCLEAN;
  	}
  
  	/* DIR_ITEM/INDEX/INODE_REF is not allowed to point to non-fs trees */
  	if (!is_fstree(key->objectid) && !is_root_item) {
  		dir_item_err(leaf, slot,
  		"invalid location key objectid, have %llu expect [%llu, %llu]",
  				key->objectid, BTRFS_FIRST_FREE_OBJECTID,
  				BTRFS_LAST_FREE_OBJECTID);
  		return -EUCLEAN;
  	}
  
  	/*
  	 * ROOT_ITEM with non-zero offset means this is a snapshot, created at
  	 * @offset transid.
  	 * Furthermore, for location key in DIR_ITEM, its offset is always -1.
  	 *
  	 * So here we only check offset for reloc tree whose key->offset must
  	 * be a valid tree.
  	 */
  	if (key->objectid == BTRFS_TREE_RELOC_OBJECTID && key->offset == 0) {
  		generic_err(leaf, slot, "invalid root id 0 for reloc tree");
  		return -EUCLEAN;
  	}
  	return 0;
  }

  static int check_dir_item(struct extent_buffer *leaf,

  			  struct btrfs_key *key, struct btrfs_key *prev_key,
  			  int slot)

  {

  	struct btrfs_fs_info *fs_info = leaf->fs_info;

  	struct btrfs_dir_item *di;
  	u32 item_size = btrfs_item_size_nr(leaf, slot);
  	u32 cur = 0;

  	if (!check_prev_ino(leaf, key, slot, prev_key))

  		return -EUCLEAN;

  	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
  	while (cur < item_size) {

  		struct btrfs_key location_key;

  		u32 name_len;
  		u32 data_len;
  		u32 max_name_len;
  		u32 total_size;
  		u32 name_hash;
  		u8 dir_type;

  		int ret;

  
  		/* header itself should not cross item boundary */
  		if (cur + sizeof(*di) > item_size) {

  			dir_item_err(leaf, slot,

  		"dir item header crosses item boundary, have %zu boundary %u",

  				cur + sizeof(*di), item_size);
  			return -EUCLEAN;
  		}

  		/* Location key check */
  		btrfs_dir_item_key_to_cpu(leaf, di, &location_key);
  		if (location_key.type == BTRFS_ROOT_ITEM_KEY) {
  			ret = check_root_key(leaf, &location_key, slot);
  			if (ret < 0)
  				return ret;
  		} else if (location_key.type == BTRFS_INODE_ITEM_KEY ||
  			   location_key.type == 0) {
  			ret = check_inode_key(leaf, &location_key, slot);
  			if (ret < 0)
  				return ret;
  		} else {
  			dir_item_err(leaf, slot,
  			"invalid location key type, have %u, expect %u or %u",
  				     location_key.type, BTRFS_ROOT_ITEM_KEY,
  				     BTRFS_INODE_ITEM_KEY);
  			return -EUCLEAN;
  		}

  		/* dir type check */
  		dir_type = btrfs_dir_type(leaf, di);
  		if (dir_type >= BTRFS_FT_MAX) {

  			dir_item_err(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(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(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(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(fs_info)) {

  			dir_item_err(leaf, slot,

  			"dir item name and data len too long, have %u max %u",
  				name_len + data_len,

  				BTRFS_MAX_XATTR_SIZE(fs_info));

  			return -EUCLEAN;
  		}
  
  		if (data_len && dir_type != BTRFS_FT_XATTR) {

  			dir_item_err(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(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(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(3, 4)

  __cold

  static void block_group_err(const struct extent_buffer *eb, int slot,

  			    const char *fmt, ...)
  {

  	const struct btrfs_fs_info *fs_info = eb->fs_info;

  	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 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.

  	 */

  	if (key->offset == 0) {

  		block_group_err(leaf, slot,

  				"invalid block group size 0");

  		return -EUCLEAN;
  	}
  
  	if (item_size != sizeof(bgi)) {

  		block_group_err(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_stack_block_group_chunk_objectid(&bgi) !=

  	    BTRFS_FIRST_CHUNK_TREE_OBJECTID) {

  		block_group_err(leaf, slot,

  		"invalid block group chunk objectid, have %llu expect %llu",

  				btrfs_stack_block_group_chunk_objectid(&bgi),

  				BTRFS_FIRST_CHUNK_TREE_OBJECTID);
  		return -EUCLEAN;
  	}

  	if (btrfs_stack_block_group_used(&bgi) > key->offset) {

  		block_group_err(leaf, slot,

  			"invalid block group used, have %llu expect [0, %llu)",

  				btrfs_stack_block_group_used(&bgi), key->offset);

  		return -EUCLEAN;
  	}

  	flags = btrfs_stack_block_group_flags(&bgi);

  	if (hweight64(flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) > 1) {

  		block_group_err(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(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;

  }

  __printf(4, 5)

  __cold

  static void chunk_err(const struct extent_buffer *leaf,

  		      const struct btrfs_chunk *chunk, u64 logical,
  		      const char *fmt, ...)
  {

  	const struct btrfs_fs_info *fs_info = leaf->fs_info;

  	bool is_sb;
  	struct va_format vaf;
  	va_list args;
  	int i;
  	int slot = -1;
  
  	/* Only superblock eb is able to have such small offset */
  	is_sb = (leaf->start == BTRFS_SUPER_INFO_OFFSET);
  
  	if (!is_sb) {
  		/*
  		 * Get the slot number by iterating through all slots, this
  		 * would provide better readability.
  		 */
  		for (i = 0; i < btrfs_header_nritems(leaf); i++) {
  			if (btrfs_item_ptr_offset(leaf, i) ==
  					(unsigned long)chunk) {
  				slot = i;
  				break;
  			}
  		}
  	}
  	va_start(args, fmt);
  	vaf.fmt = fmt;
  	vaf.va = &args;
  
  	if (is_sb)
  		btrfs_crit(fs_info,
  		"corrupt superblock syschunk array: chunk_start=%llu, %pV",
  			   logical, &vaf);
  	else
  		btrfs_crit(fs_info,
  	"corrupt leaf: root=%llu block=%llu slot=%d chunk_start=%llu, %pV",
  			   BTRFS_CHUNK_TREE_OBJECTID, leaf->start, slot,
  			   logical, &vaf);
  	va_end(args);
  }

  /*
   * The common chunk check which could also work on super block sys chunk array.
   *

   * Return -EUCLEAN if anything is corrupted.

   * Return 0 if everything is OK.
   */

  int btrfs_check_chunk_valid(struct extent_buffer *leaf,

  			    struct btrfs_chunk *chunk, u64 logical)
  {

  	struct btrfs_fs_info *fs_info = leaf->fs_info;

  	u64 length;

  	u64 chunk_end;

  	u64 stripe_len;
  	u16 num_stripes;
  	u16 sub_stripes;
  	u64 type;
  	u64 features;
  	bool mixed = false;

  	int raid_index;
  	int nparity;
  	int ncopies;

  
  	length = btrfs_chunk_length(leaf, chunk);
  	stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
  	num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
  	sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
  	type = btrfs_chunk_type(leaf, chunk);

  	raid_index = btrfs_bg_flags_to_raid_index(type);
  	ncopies = btrfs_raid_array[raid_index].ncopies;
  	nparity = btrfs_raid_array[raid_index].nparity;

  
  	if (!num_stripes) {

  		chunk_err(leaf, chunk, logical,

  			  "invalid chunk num_stripes, have %u", num_stripes);

  		return -EUCLEAN;

  	}

  	if (num_stripes < ncopies) {
  		chunk_err(leaf, chunk, logical,
  			  "invalid chunk num_stripes < ncopies, have %u < %d",
  			  num_stripes, ncopies);
  		return -EUCLEAN;
  	}
  	if (nparity && num_stripes == nparity) {
  		chunk_err(leaf, chunk, logical,
  			  "invalid chunk num_stripes == nparity, have %u == %d",
  			  num_stripes, nparity);
  		return -EUCLEAN;
  	}

  	if (!IS_ALIGNED(logical, fs_info->sectorsize)) {

  		chunk_err(leaf, chunk, logical,

  		"invalid chunk logical, have %llu should aligned to %u",
  			  logical, fs_info->sectorsize);

  		return -EUCLEAN;

  	}
  	if (btrfs_chunk_sector_size(leaf, chunk) != fs_info->sectorsize) {

  		chunk_err(leaf, chunk, logical,

  			  "invalid chunk sectorsize, have %u expect %u",
  			  btrfs_chunk_sector_size(leaf, chunk),
  			  fs_info->sectorsize);

  		return -EUCLEAN;

  	}
  	if (!length || !IS_ALIGNED(length, fs_info->sectorsize)) {

  		chunk_err(leaf, chunk, logical,

  			  "invalid chunk length, have %llu", length);

  		return -EUCLEAN;

  	}

  	if (unlikely(check_add_overflow(logical, length, &chunk_end))) {
  		chunk_err(leaf, chunk, logical,
  "invalid chunk logical start and length, have logical start %llu length %llu",
  			  logical, length);
  		return -EUCLEAN;
  	}

  	if (!is_power_of_2(stripe_len) || stripe_len != BTRFS_STRIPE_LEN) {

  		chunk_err(leaf, chunk, logical,

  			  "invalid chunk stripe length: %llu",

  			  stripe_len);

  		return -EUCLEAN;

  	}
  	if (~(BTRFS_BLOCK_GROUP_TYPE_MASK | BTRFS_BLOCK_GROUP_PROFILE_MASK) &
  	    type) {

  		chunk_err(leaf, chunk, logical,

  			  "unrecognized chunk type: 0x%llx",

  			  ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
  			    BTRFS_BLOCK_GROUP_PROFILE_MASK) &
  			  btrfs_chunk_type(leaf, chunk));

  		return -EUCLEAN;

  	}

  	if (!has_single_bit_set(type & BTRFS_BLOCK_GROUP_PROFILE_MASK) &&

  	    (type & BTRFS_BLOCK_GROUP_PROFILE_MASK) != 0) {

  		chunk_err(leaf, chunk, logical,

  		"invalid chunk profile flag: 0x%llx, expect 0 or 1 bit set",
  			  type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
  		return -EUCLEAN;
  	}

  	if ((type & BTRFS_BLOCK_GROUP_TYPE_MASK) == 0) {

  		chunk_err(leaf, chunk, logical,

  	"missing chunk type flag, have 0x%llx one bit must be set in 0x%llx",
  			  type, BTRFS_BLOCK_GROUP_TYPE_MASK);

  		return -EUCLEAN;

  	}
  
  	if ((type & BTRFS_BLOCK_GROUP_SYSTEM) &&
  	    (type & (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA))) {

  		chunk_err(leaf, chunk, logical,

  			  "system chunk with data or metadata type: 0x%llx",
  			  type);

  		return -EUCLEAN;

  	}
  
  	features = btrfs_super_incompat_flags(fs_info->super_copy);
  	if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
  		mixed = true;
  
  	if (!mixed) {
  		if ((type & BTRFS_BLOCK_GROUP_METADATA) &&
  		    (type & BTRFS_BLOCK_GROUP_DATA)) {

  			chunk_err(leaf, chunk, logical,

  			"mixed chunk type in non-mixed mode: 0x%llx", type);

  			return -EUCLEAN;

  		}
  	}
  
  	if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) ||
  	    (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes != 2) ||
  	    (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
  	    (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) ||
  	    (type & BTRFS_BLOCK_GROUP_DUP && num_stripes != 2) ||
  	    ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 && num_stripes != 1)) {

  		chunk_err(leaf, chunk, logical,

  			"invalid num_stripes:sub_stripes %u:%u for profile %llu",
  			num_stripes, sub_stripes,
  			type & BTRFS_BLOCK_GROUP_PROFILE_MASK);

  		return -EUCLEAN;

  	}
  
  	return 0;

  }

  /*
   * Enhanced version of chunk item checker.
   *
   * The common btrfs_check_chunk_valid() doesn't check item size since it needs
   * to work on super block sys_chunk_array which doesn't have full item ptr.
   */
  static int check_leaf_chunk_item(struct extent_buffer *leaf,
  				 struct btrfs_chunk *chunk,
  				 struct btrfs_key *key, int slot)
  {
  	int num_stripes;
  
  	if (btrfs_item_size_nr(leaf, slot) < sizeof(struct btrfs_chunk)) {
  		chunk_err(leaf, chunk, key->offset,
  			"invalid chunk item size: have %u expect [%zu, %u)",
  			btrfs_item_size_nr(leaf, slot),
  			sizeof(struct btrfs_chunk),
  			BTRFS_LEAF_DATA_SIZE(leaf->fs_info));
  		return -EUCLEAN;
  	}
  
  	num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
  	/* Let btrfs_check_chunk_valid() handle this error type */
  	if (num_stripes == 0)
  		goto out;
  
  	if (btrfs_chunk_item_size(num_stripes) !=
  	    btrfs_item_size_nr(leaf, slot)) {
  		chunk_err(leaf, chunk, key->offset,
  			"invalid chunk item size: have %u expect %lu",
  			btrfs_item_size_nr(leaf, slot),
  			btrfs_chunk_item_size(num_stripes));
  		return -EUCLEAN;
  	}
  out:
  	return btrfs_check_chunk_valid(leaf, chunk, key->offset);
  }

  __printf(3, 4)

  __cold

  static void dev_item_err(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(eb->fs_info,

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

  static int check_dev_item(struct extent_buffer *leaf,

  			  struct btrfs_key *key, int slot)
  {
  	struct btrfs_dev_item *ditem;

  
  	if (key->objectid != BTRFS_DEV_ITEMS_OBJECTID) {

  		dev_item_err(leaf, slot,

  			     "invalid objectid: has=%llu expect=%llu",
  			     key->objectid, BTRFS_DEV_ITEMS_OBJECTID);
  		return -EUCLEAN;
  	}

  	ditem = btrfs_item_ptr(leaf, slot, struct btrfs_dev_item);
  	if (btrfs_device_id(leaf, ditem) != key->offset) {

  		dev_item_err(leaf, slot,

  			     "devid mismatch: key has=%llu item has=%llu",
  			     key->offset, btrfs_device_id(leaf, ditem));
  		return -EUCLEAN;
  	}
  
  	/*
  	 * For device total_bytes, we don't have reliable way to check it, as
  	 * it can be 0 for device removal. Device size check can only be done
  	 * by dev extents check.
  	 */
  	if (btrfs_device_bytes_used(leaf, ditem) >
  	    btrfs_device_total_bytes(leaf, ditem)) {

  		dev_item_err(leaf, slot,

  			     "invalid bytes used: have %llu expect [0, %llu]",
  			     btrfs_device_bytes_used(leaf, ditem),
  			     btrfs_device_total_bytes(leaf, ditem));
  		return -EUCLEAN;
  	}
  	/*
  	 * Remaining members like io_align/type/gen/dev_group aren't really
  	 * utilized.  Skip them to make later usage of them easier.
  	 */
  	return 0;
  }

  static int check_inode_item(struct extent_buffer *leaf,

  			    struct btrfs_key *key, int slot)
  {

  	struct btrfs_fs_info *fs_info = leaf->fs_info;

  	struct btrfs_inode_item *iitem;
  	u64 super_gen = btrfs_super_generation(fs_info->super_copy);
  	u32 valid_mask = (S_IFMT | S_ISUID | S_ISGID | S_ISVTX | 0777);
  	u32 mode;

  	int ret;
  
  	ret = check_inode_key(leaf, key, slot);
  	if (ret < 0)
  		return ret;

  	iitem = btrfs_item_ptr(leaf, slot, struct btrfs_inode_item);
  
  	/* Here we use super block generation + 1 to handle log tree */
  	if (btrfs_inode_generation(leaf, iitem) > super_gen + 1) {

  		inode_item_err(leaf, slot,

  			"invalid inode generation: has %llu expect (0, %llu]",
  			       btrfs_inode_generation(leaf, iitem),
  			       super_gen + 1);
  		return -EUCLEAN;
  	}
  	/* Note for ROOT_TREE_DIR_ITEM, mkfs could set its transid 0 */
  	if (btrfs_inode_transid(leaf, iitem) > super_gen + 1) {

  		inode_item_err(leaf, slot,

  			"invalid inode transid: has %llu expect [0, %llu]",

  			       btrfs_inode_transid(leaf, iitem), super_gen + 1);
  		return -EUCLEAN;
  	}
  
  	/*
  	 * For size and nbytes it's better not to be too strict, as for dir
  	 * item its size/nbytes can easily get wrong, but doesn't affect
  	 * anything in the fs. So here we skip the check.
  	 */
  	mode = btrfs_inode_mode(leaf, iitem);
  	if (mode & ~valid_mask) {

  		inode_item_err(leaf, slot,

  			       "unknown mode bit detected: 0x%x",
  			       mode & ~valid_mask);
  		return -EUCLEAN;
  	}
  
  	/*

  	 * S_IFMT is not bit mapped so we can't completely rely on
  	 * is_power_of_2/has_single_bit_set, but it can save us from checking
  	 * FIFO/CHR/DIR/REG.  Only needs to check BLK, LNK and SOCKS

  	 */

  	if (!has_single_bit_set(mode & S_IFMT)) {

  		if (!S_ISLNK(mode) && !S_ISBLK(mode) && !S_ISSOCK(mode)) {

  			inode_item_err(leaf, slot,

  			"invalid mode: has 0%o expect valid S_IF* bit(s)",
  				       mode & S_IFMT);
  			return -EUCLEAN;
  		}
  	}
  	if (S_ISDIR(mode) && btrfs_inode_nlink(leaf, iitem) > 1) {

  		inode_item_err(leaf, slot,

  		       "invalid nlink: has %u expect no more than 1 for dir",
  			btrfs_inode_nlink(leaf, iitem));
  		return -EUCLEAN;
  	}
  	if (btrfs_inode_flags(leaf, iitem) & ~BTRFS_INODE_FLAG_MASK) {

  		inode_item_err(leaf, slot,

  			       "unknown flags detected: 0x%llx",
  			       btrfs_inode_flags(leaf, iitem) &
  			       ~BTRFS_INODE_FLAG_MASK);
  		return -EUCLEAN;
  	}
  	return 0;
  }

  static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key,
  			   int slot)
  {
  	struct btrfs_fs_info *fs_info = leaf->fs_info;

  	struct btrfs_root_item ri = { 0 };

  	const u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY |
  				     BTRFS_ROOT_SUBVOL_DEAD;

  	int ret;

  	ret = check_root_key(leaf, key, slot);
  	if (ret < 0)
  		return ret;

  	if (btrfs_item_size_nr(leaf, slot) != sizeof(ri) &&
  	    btrfs_item_size_nr(leaf, slot) != btrfs_legacy_root_item_size()) {

  		generic_err(leaf, slot,

  			    "invalid root item size, have %u expect %zu or %u",
  			    btrfs_item_size_nr(leaf, slot), sizeof(ri),
  			    btrfs_legacy_root_item_size());

  		return -EUCLEAN;

  	}

  	/*
  	 * For legacy root item, the members starting at generation_v2 will be
  	 * all filled with 0.
  	 * And since we allow geneartion_v2 as 0, it will still pass the check.
  	 */

  	read_extent_buffer(leaf, &ri, btrfs_item_ptr_offset(leaf, slot),

  			   btrfs_item_size_nr(leaf, slot));

  
  	/* Generation related */
  	if (btrfs_root_generation(&ri) >
  	    btrfs_super_generation(fs_info->super_copy) + 1) {
  		generic_err(leaf, slot,
  			"invalid root generation, have %llu expect (0, %llu]",
  			    btrfs_root_generation(&ri),
  			    btrfs_super_generation(fs_info->super_copy) + 1);
  		return -EUCLEAN;
  	}
  	if (btrfs_root_generation_v2(&ri) >
  	    btrfs_super_generation(fs_info->super_copy) + 1) {
  		generic_err(leaf, slot,
  		"invalid root v2 generation, have %llu expect (0, %llu]",
  			    btrfs_root_generation_v2(&ri),
  			    btrfs_super_generation(fs_info->super_copy) + 1);
  		return -EUCLEAN;
  	}
  	if (btrfs_root_last_snapshot(&ri) >
  	    btrfs_super_generation(fs_info->super_copy) + 1) {
  		generic_err(leaf, slot,
  		"invalid root last_snapshot, have %llu expect (0, %llu]",
  			    btrfs_root_last_snapshot(&ri),
  			    btrfs_super_generation(fs_info->super_copy) + 1);
  		return -EUCLEAN;
  	}
  
  	/* Alignment and level check */
  	if (!IS_ALIGNED(btrfs_root_bytenr(&ri), fs_info->sectorsize)) {
  		generic_err(leaf, slot,
  		"invalid root bytenr, have %llu expect to be aligned to %u",
  			    btrfs_root_bytenr(&ri), fs_info->sectorsize);
  		return -EUCLEAN;
  	}
  	if (btrfs_root_level(&ri) >= BTRFS_MAX_LEVEL) {
  		generic_err(leaf, slot,
  			    "invalid root level, have %u expect [0, %u]",
  			    btrfs_root_level(&ri), BTRFS_MAX_LEVEL - 1);
  		return -EUCLEAN;
  	}
  	if (ri.drop_level >= BTRFS_MAX_LEVEL) {
  		generic_err(leaf, slot,
  			    "invalid root level, have %u expect [0, %u]",
  			    ri.drop_level, BTRFS_MAX_LEVEL - 1);
  		return -EUCLEAN;
  	}
  
  	/* Flags check */
  	if (btrfs_root_flags(&ri) & ~valid_root_flags) {
  		generic_err(leaf, slot,
  			    "invalid root flags, have 0x%llx expect mask 0x%llx",
  			    btrfs_root_flags(&ri), valid_root_flags);
  		return -EUCLEAN;
  	}
  	return 0;
  }

  __printf(3,4)
  __cold
  static void extent_err(const struct extent_buffer *eb, int slot,
  		       const char *fmt, ...)
  {
  	struct btrfs_key key;
  	struct va_format vaf;
  	va_list args;
  	u64 bytenr;
  	u64 len;
  
  	btrfs_item_key_to_cpu(eb, &key, slot);
  	bytenr = key.objectid;

  	if (key.type == BTRFS_METADATA_ITEM_KEY ||
  	    key.type == BTRFS_TREE_BLOCK_REF_KEY ||
  	    key.type == BTRFS_SHARED_BLOCK_REF_KEY)

  		len = eb->fs_info->nodesize;
  	else
  		len = key.offset;
  	va_start(args, fmt);
  
  	vaf.fmt = fmt;
  	vaf.va = &args;
  
  	btrfs_crit(eb->fs_info,
  	"corrupt %s: block=%llu slot=%d extent bytenr=%llu len=%llu %pV",
  		btrfs_header_level(eb) == 0 ? "leaf" : "node",
  		eb->start, slot, bytenr, len, &vaf);
  	va_end(args);
  }
  
  static int check_extent_item(struct extent_buffer *leaf,
  			     struct btrfs_key *key, int slot)
  {
  	struct btrfs_fs_info *fs_info = leaf->fs_info;
  	struct btrfs_extent_item *ei;
  	bool is_tree_block = false;
  	unsigned long ptr;	/* Current pointer inside inline refs */
  	unsigned long end;	/* Extent item end */
  	const u32 item_size = btrfs_item_size_nr(leaf, slot);
  	u64 flags;
  	u64 generation;
  	u64 total_refs;		/* Total refs in btrfs_extent_item */
  	u64 inline_refs = 0;	/* found total inline refs */
  
  	if (key->type == BTRFS_METADATA_ITEM_KEY &&
  	    !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
  		generic_err(leaf, slot,
  "invalid key type, METADATA_ITEM type invalid when SKINNY_METADATA feature disabled");
  		return -EUCLEAN;
  	}
  	/* key->objectid is the bytenr for both key types */
  	if (!IS_ALIGNED(key->objectid, fs_info->sectorsize)) {
  		generic_err(leaf, slot,
  		"invalid key objectid, have %llu expect to be aligned to %u",
  			   key->objectid, fs_info->sectorsize);
  		return -EUCLEAN;
  	}
  
  	/* key->offset is tree level for METADATA_ITEM_KEY */
  	if (key->type == BTRFS_METADATA_ITEM_KEY &&
  	    key->offset >= BTRFS_MAX_LEVEL) {
  		extent_err(leaf, slot,
  			   "invalid tree level, have %llu expect [0, %u]",
  			   key->offset, BTRFS_MAX_LEVEL - 1);
  		return -EUCLEAN;
  	}
  
  	/*
  	 * EXTENT/METADATA_ITEM consists of:
  	 * 1) One btrfs_extent_item
  	 *    Records the total refs, type and generation of the extent.
  	 *
  	 * 2) One btrfs_tree_block_info (for EXTENT_ITEM and tree backref only)
  	 *    Records the first key and level of the tree block.
  	 *
  	 * 2) Zero or more btrfs_extent_inline_ref(s)
  	 *    Each inline ref has one btrfs_extent_inline_ref shows:
  	 *    2.1) The ref type, one of the 4
  	 *         TREE_BLOCK_REF	Tree block only
  	 *         SHARED_BLOCK_REF	Tree block only
  	 *         EXTENT_DATA_REF	Data only
  	 *         SHARED_DATA_REF	Data only
  	 *    2.2) Ref type specific data
  	 *         Either using btrfs_extent_inline_ref::offset, or specific
  	 *         data structure.
  	 */
  	if (item_size < sizeof(*ei)) {
  		extent_err(leaf, slot,
  			   "invalid item size, have %u expect [%zu, %u)",
  			   item_size, sizeof(*ei),
  			   BTRFS_LEAF_DATA_SIZE(fs_info));
  		return -EUCLEAN;
  	}
  	end = item_size + btrfs_item_ptr_offset(leaf, slot);
  
  	/* Checks against extent_item */
  	ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
  	flags = btrfs_extent_flags(leaf, ei);
  	total_refs = btrfs_extent_refs(leaf, ei);
  	generation = btrfs_extent_generation(leaf, ei);
  	if (generation > btrfs_super_generation(fs_info->super_copy) + 1) {
  		extent_err(leaf, slot,
  			   "invalid generation, have %llu expect (0, %llu]",
  			   generation,
  			   btrfs_super_generation(fs_info->super_copy) + 1);
  		return -EUCLEAN;
  	}

  	if (!has_single_bit_set(flags & (BTRFS_EXTENT_FLAG_DATA |
  					 BTRFS_EXTENT_FLAG_TREE_BLOCK))) {

  		extent_err(leaf, slot,
  		"invalid extent flag, have 0x%llx expect 1 bit set in 0x%llx",
  			flags, BTRFS_EXTENT_FLAG_DATA |
  			BTRFS_EXTENT_FLAG_TREE_BLOCK);
  		return -EUCLEAN;
  	}
  	is_tree_block = !!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK);
  	if (is_tree_block) {
  		if (key->type == BTRFS_EXTENT_ITEM_KEY &&
  		    key->offset != fs_info->nodesize) {
  			extent_err(leaf, slot,
  				   "invalid extent length, have %llu expect %u",
  				   key->offset, fs_info->nodesize);
  			return -EUCLEAN;
  		}
  	} else {
  		if (key->type != BTRFS_EXTENT_ITEM_KEY) {
  			extent_err(leaf, slot,
  			"invalid key type, have %u expect %u for data backref",
  				   key->type, BTRFS_EXTENT_ITEM_KEY);
  			return -EUCLEAN;
  		}
  		if (!IS_ALIGNED(key->offset, fs_info->sectorsize)) {
  			extent_err(leaf, slot,
  			"invalid extent length, have %llu expect aligned to %u",
  				   key->offset, fs_info->sectorsize);
  			return -EUCLEAN;
  		}
  	}
  	ptr = (unsigned long)(struct btrfs_extent_item *)(ei + 1);
  
  	/* Check the special case of btrfs_tree_block_info */
  	if (is_tree_block && key->type != BTRFS_METADATA_ITEM_KEY) {
  		struct btrfs_tree_block_info *info;
  
  		info = (struct btrfs_tree_block_info *)ptr;
  		if (btrfs_tree_block_level(leaf, info) >= BTRFS_MAX_LEVEL) {
  			extent_err(leaf, slot,
  			"invalid tree block info level, have %u expect [0, %u]",
  				   btrfs_tree_block_level(leaf, info),
  				   BTRFS_MAX_LEVEL - 1);
  			return -EUCLEAN;
  		}
  		ptr = (unsigned long)(struct btrfs_tree_block_info *)(info + 1);
  	}
  
  	/* Check inline refs */
  	while (ptr < end) {
  		struct btrfs_extent_inline_ref *iref;
  		struct btrfs_extent_data_ref *dref;
  		struct btrfs_shared_data_ref *sref;
  		u64 dref_offset;
  		u64 inline_offset;
  		u8 inline_type;
  
  		if (ptr + sizeof(*iref) > end) {
  			extent_err(leaf, slot,
  "inline ref item overflows extent item, ptr %lu iref size %zu end %lu",
  				   ptr, sizeof(*iref), end);
  			return -EUCLEAN;
  		}
  		iref = (struct btrfs_extent_inline_ref *)ptr;
  		inline_type = btrfs_extent_inline_ref_type(leaf, iref);
  		inline_offset = btrfs_extent_inline_ref_offset(leaf, iref);
  		if (ptr + btrfs_extent_inline_ref_size(inline_type) > end) {
  			extent_err(leaf, slot,
  "inline ref item overflows extent item, ptr %lu iref size %u end %lu",
  				   ptr, inline_type, end);
  			return -EUCLEAN;
  		}
  
  		switch (inline_type) {
  		/* inline_offset is subvolid of the owner, no need to check */
  		case BTRFS_TREE_BLOCK_REF_KEY:
  			inline_refs++;
  			break;
  		/* Contains parent bytenr */
  		case BTRFS_SHARED_BLOCK_REF_KEY:
  			if (!IS_ALIGNED(inline_offset, fs_info->sectorsize)) {
  				extent_err(leaf, slot,
  		"invalid tree parent bytenr, have %llu expect aligned to %u",
  					   inline_offset, fs_info->sectorsize);
  				return -EUCLEAN;
  			}
  			inline_refs++;
  			break;
  		/*
  		 * Contains owner subvolid, owner key objectid, adjusted offset.
  		 * The only obvious corruption can happen in that offset.
  		 */
  		case BTRFS_EXTENT_DATA_REF_KEY:
  			dref = (struct btrfs_extent_data_ref *)(&iref->offset);
  			dref_offset = btrfs_extent_data_ref_offset(leaf, dref);
  			if (!IS_ALIGNED(dref_offset, fs_info->sectorsize)) {
  				extent_err(leaf, slot,
  		"invalid data ref offset, have %llu expect aligned to %u",
  					   dref_offset, fs_info->sectorsize);
  				return -EUCLEAN;
  			}
  			inline_refs += btrfs_extent_data_ref_count(leaf, dref);
  			break;
  		/* Contains parent bytenr and ref count */
  		case BTRFS_SHARED_DATA_REF_KEY:
  			sref = (struct btrfs_shared_data_ref *)(iref + 1);
  			if (!IS_ALIGNED(inline_offset, fs_info->sectorsize)) {
  				extent_err(leaf, slot,
  		"invalid data parent bytenr, have %llu expect aligned to %u",
  					   inline_offset, fs_info->sectorsize);
  				return -EUCLEAN;
  			}
  			inline_refs += btrfs_shared_data_ref_count(leaf, sref);
  			break;
  		default:
  			extent_err(leaf, slot, "unknown inline ref type: %u",
  				   inline_type);
  			return -EUCLEAN;
  		}
  		ptr += btrfs_extent_inline_ref_size(inline_type);
  	}
  	/* No padding is allowed */
  	if (ptr != end) {
  		extent_err(leaf, slot,
  			   "invalid extent item size, padding bytes found");
  		return -EUCLEAN;
  	}
  
  	/* Finally, check the inline refs against total refs */
  	if (inline_refs > total_refs) {
  		extent_err(leaf, slot,
  			"invalid extent refs, have %llu expect >= inline %llu",
  			   total_refs, inline_refs);
  		return -EUCLEAN;
  	}
  	return 0;
  }

  static int check_simple_keyed_refs(struct extent_buffer *leaf,
  				   struct btrfs_key *key, int slot)
  {
  	u32 expect_item_size = 0;
  
  	if (key->type == BTRFS_SHARED_DATA_REF_KEY)
  		expect_item_size = sizeof(struct btrfs_shared_data_ref);
  
  	if (btrfs_item_size_nr(leaf, slot) != expect_item_size) {
  		generic_err(leaf, slot,
  		"invalid item size, have %u expect %u for key type %u",
  			    btrfs_item_size_nr(leaf, slot),
  			    expect_item_size, key->type);
  		return -EUCLEAN;
  	}
  	if (!IS_ALIGNED(key->objectid, leaf->fs_info->sectorsize)) {
  		generic_err(leaf, slot,
  "invalid key objectid for shared block ref, have %llu expect aligned to %u",
  			    key->objectid, leaf->fs_info->sectorsize);
  		return -EUCLEAN;
  	}
  	if (key->type != BTRFS_TREE_BLOCK_REF_KEY &&
  	    !IS_ALIGNED(key->offset, leaf->fs_info->sectorsize)) {
  		extent_err(leaf, slot,
  		"invalid tree parent bytenr, have %llu expect aligned to %u",
  			   key->offset, leaf->fs_info->sectorsize);
  		return -EUCLEAN;
  	}
  	return 0;
  }

  static int check_extent_data_ref(struct extent_buffer *leaf,
  				 struct btrfs_key *key, int slot)
  {
  	struct btrfs_extent_data_ref *dref;
  	unsigned long ptr = btrfs_item_ptr_offset(leaf, slot);
  	const unsigned long end = ptr + btrfs_item_size_nr(leaf, slot);
  
  	if (btrfs_item_size_nr(leaf, slot) % sizeof(*dref) != 0) {
  		generic_err(leaf, slot,
  	"invalid item size, have %u expect aligned to %zu for key type %u",
  			    btrfs_item_size_nr(leaf, slot),
  			    sizeof(*dref), key->type);

  		return -EUCLEAN;

  	}
  	if (!IS_ALIGNED(key->objectid, leaf->fs_info->sectorsize)) {
  		generic_err(leaf, slot,
  "invalid key objectid for shared block ref, have %llu expect aligned to %u",
  			    key->objectid, leaf->fs_info->sectorsize);
  		return -EUCLEAN;
  	}
  	for (; ptr < end; ptr += sizeof(*dref)) {
  		u64 root_objectid;
  		u64 owner;
  		u64 offset;
  		u64 hash;
  
  		dref = (struct btrfs_extent_data_ref *)ptr;
  		root_objectid = btrfs_extent_data_ref_root(leaf, dref);
  		owner = btrfs_extent_data_ref_objectid(leaf, dref);
  		offset = btrfs_extent_data_ref_offset(leaf, dref);
  		hash = hash_extent_data_ref(root_objectid, owner, offset);
  		if (hash != key->offset) {
  			extent_err(leaf, slot,
  	"invalid extent data ref hash, item has 0x%016llx key has 0x%016llx",
  				   hash, key->offset);
  			return -EUCLEAN;
  		}
  		if (!IS_ALIGNED(offset, leaf->fs_info->sectorsize)) {
  			extent_err(leaf, slot,
  	"invalid extent data backref offset, have %llu expect aligned to %u",
  				   offset, leaf->fs_info->sectorsize);

  			return -EUCLEAN;

  		}
  	}
  	return 0;
  }

  #define inode_ref_err(eb, slot, fmt, args...)			\
  	inode_item_err(eb, slot, fmt, ##args)

  static int check_inode_ref(struct extent_buffer *leaf,
  			   struct btrfs_key *key, struct btrfs_key *prev_key,
  			   int slot)
  {
  	struct btrfs_inode_ref *iref;
  	unsigned long ptr;
  	unsigned long end;

  	if (!check_prev_ino(leaf, key, slot, prev_key))
  		return -EUCLEAN;

  	/* namelen can't be 0, so item_size == sizeof() is also invalid */
  	if (btrfs_item_size_nr(leaf, slot) <= sizeof(*iref)) {

  		inode_ref_err(leaf, slot,

  			"invalid item size, have %u expect (%zu, %u)",
  			btrfs_item_size_nr(leaf, slot),
  			sizeof(*iref), BTRFS_LEAF_DATA_SIZE(leaf->fs_info));
  		return -EUCLEAN;
  	}
  
  	ptr = btrfs_item_ptr_offset(leaf, slot);
  	end = ptr + btrfs_item_size_nr(leaf, slot);
  	while (ptr < end) {
  		u16 namelen;
  
  		if (ptr + sizeof(iref) > end) {

  			inode_ref_err(leaf, slot,

  			"inode ref overflow, ptr %lu end %lu inode_ref_size %zu",
  				ptr, end, sizeof(iref));
  			return -EUCLEAN;
  		}
  
  		iref = (struct btrfs_inode_ref *)ptr;
  		namelen = btrfs_inode_ref_name_len(leaf, iref);
  		if (ptr + sizeof(*iref) + namelen > end) {

  			inode_ref_err(leaf, slot,

  				"inode ref overflow, ptr %lu end %lu namelen %u",
  				ptr, end, namelen);
  			return -EUCLEAN;
  		}
  
  		/*
  		 * NOTE: In theory we should record all found index numbers
  		 * to find any duplicated indexes, but that will be too time
  		 * consuming for inodes with too many hard links.
  		 */
  		ptr += sizeof(*iref) + namelen;
  	}
  	return 0;
  }

  /*

   * Common point to switch the item-specific validation.
   */

  static int check_leaf_item(struct extent_buffer *leaf,

  			   struct btrfs_key *key, int slot,
  			   struct btrfs_key *prev_key)

  {
  	int ret = 0;

  	struct btrfs_chunk *chunk;

  
  	switch (key->type) {
  	case BTRFS_EXTENT_DATA_KEY:

  		ret = check_extent_data_item(leaf, key, slot, prev_key);

  		break;
  	case BTRFS_EXTENT_CSUM_KEY:

  		ret = check_csum_item(leaf, key, slot, prev_key);

  		break;

  	case BTRFS_DIR_ITEM_KEY:
  	case BTRFS_DIR_INDEX_KEY:
  	case BTRFS_XATTR_ITEM_KEY:

  		ret = check_dir_item(leaf, key, prev_key, slot);

  		break;

  	case BTRFS_INODE_REF_KEY:
  		ret = check_inode_ref(leaf, key, prev_key, slot);
  		break;

  	case BTRFS_BLOCK_GROUP_ITEM_KEY:

  		ret = check_block_group_item(leaf, key, slot);

  		break;

  	case BTRFS_CHUNK_ITEM_KEY:
  		chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);

  		ret = check_leaf_chunk_item(leaf, chunk, key, slot);

  		break;

  	case BTRFS_DEV_ITEM_KEY:

  		ret = check_dev_item(leaf, key, slot);

  		break;

  	case BTRFS_INODE_ITEM_KEY:

  		ret = check_inode_item(leaf, key, slot);

  		break;

  	case BTRFS_ROOT_ITEM_KEY:
  		ret = check_root_item(leaf, key, slot);
  		break;

  	case BTRFS_EXTENT_ITEM_KEY:
  	case BTRFS_METADATA_ITEM_KEY:
  		ret = check_extent_item(leaf, key, slot);
  		break;

  	case BTRFS_TREE_BLOCK_REF_KEY:
  	case BTRFS_SHARED_DATA_REF_KEY:
  	case BTRFS_SHARED_BLOCK_REF_KEY:
  		ret = check_simple_keyed_refs(leaf, key, slot);
  		break;

  	case BTRFS_EXTENT_DATA_REF_KEY:
  		ret = check_extent_data_ref(leaf, key, slot);
  		break;

  	}
  	return ret;
  }

  static int check_leaf(struct extent_buffer *leaf, bool check_item_data)

  {

  	struct btrfs_fs_info *fs_info = leaf->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(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);

  		/* 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(leaf, 0,

  			"invalid root, root %llu must never be empty",
  				    owner);
  			return -EUCLEAN;
  		}

  		/* Unknown tree */
  		if (owner == 0) {
  			generic_err(leaf, 0,
  				"invalid owner, root 0 is not defined");
  			return -EUCLEAN;
  		}

  		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) {

  			generic_err(leaf, slot,

  	"bad key order, prev (%llu %u %llu) current (%llu %u %llu)",
  				prev_key.objectid, prev_key.type,
  				prev_key.offset, key.objectid, key.type,
  				key.offset);

  			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(fs_info);
  		else
  			item_end_expected = btrfs_item_offset_nr(leaf,
  								 slot - 1);
  		if (btrfs_item_end_nr(leaf, slot) != item_end_expected) {

  			generic_err(leaf, slot,

  				"unexpected item end, have %u expect %u",
  				btrfs_item_end_nr(leaf, slot),
  				item_end_expected);

  			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(fs_info)) {

  			generic_err(leaf, slot,

  			"slot end outside of leaf, have %u expect range [0, %u]",
  				btrfs_item_end_nr(leaf, slot),
  				BTRFS_LEAF_DATA_SIZE(fs_info));

  			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)) {

  			generic_err(leaf, slot,

  		"slot overlaps with its data, item end %lu data start %lu",
  				btrfs_item_nr_offset(slot) +
  				sizeof(struct btrfs_item),
  				btrfs_item_ptr_offset(leaf, slot));

  			return -EUCLEAN;
  		}

  		if (check_item_data) {
  			/*
  			 * Check if the item size and content meet other
  			 * criteria
  			 */

  			ret = check_leaf_item(leaf, &key, slot, &prev_key);

  			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 extent_buffer *leaf)

  {

  	return check_leaf(leaf, true);

  }

  ALLOW_ERROR_INJECTION(btrfs_check_leaf_full, ERRNO);

  int btrfs_check_leaf_relaxed(struct extent_buffer *leaf)

  {

  	return check_leaf(leaf, false);

  }

  int btrfs_check_node(struct extent_buffer *node)

  {

  	struct btrfs_fs_info *fs_info = node->fs_info;

  	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(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(fs_info)) {
  		btrfs_crit(fs_info,

  "corrupt node: root=%llu block=%llu, nritems too %s, have %lu expect range [1,%u]",

  			   btrfs_header_owner(node), node->start,

  			   nr == 0 ? "small" : "large", nr,

  			   BTRFS_NODEPTRS_PER_BLOCK(fs_info));

  		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(node, slot,

  				"invalid NULL node pointer");
  			ret = -EUCLEAN;
  			goto out;
  		}

  		if (!IS_ALIGNED(bytenr, fs_info->sectorsize)) {

  			generic_err(node, slot,

  			"unaligned pointer, have %llu should be aligned to %u",

  				bytenr, fs_info->sectorsize);

  			ret = -EUCLEAN;

  			goto out;
  		}
  
  		if (btrfs_comp_cpu_keys(&key, &next_key) >= 0) {

  			generic_err(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;
  }

  ALLOW_ERROR_INJECTION(btrfs_check_node, ERRNO);