fs/btrfs/uuid-tree.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) STRATO AG 2013.  All rights reserved.
  */

 #include <linux/uuid.h>
 #include <asm/unaligned.h>
 #include "messages.h"
 #include "ctree.h"
 #include "transaction.h"
 #include "disk-io.h"
 #include "fs.h"
 #include "accessors.h"
 #include "uuid-tree.h"

 static void btrfs_uuid_to_key(const u8 *uuid, u8 type, struct btrfs_key *key)
 {
 	key->type = type;
 	key->objectid = get_unaligned_le64(uuid);
 	key->offset = get_unaligned_le64(uuid + sizeof(u64));
 }

 /* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
 static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, const u8 *uuid,
 				  u8 type, u64 subid)
 {
 	int ret;
 	struct btrfs_path *path = NULL;
 	struct extent_buffer *eb;
 	int slot;
 	u32 item_size;
 	unsigned long offset;
 	struct btrfs_key key;

 	if (WARN_ON_ONCE(!uuid_root)) {
 		ret = -ENOENT;
 		goto out;
 	}

 	path = btrfs_alloc_path();
 	if (!path) {
 		ret = -ENOMEM;
 		goto out;
 	}

 	btrfs_uuid_to_key(uuid, type, &key);
 	ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
 	if (ret < 0) {
 		goto out;
 	} else if (ret > 0) {
 		ret = -ENOENT;
 		goto out;
 	}

 	eb = path->nodes[0];
 	slot = path->slots[0];
 	item_size = btrfs_item_size(eb, slot);
 	offset = btrfs_item_ptr_offset(eb, slot);
 	ret = -ENOENT;

 	if (!IS_ALIGNED(item_size, sizeof(u64))) {
 		btrfs_warn(uuid_root->fs_info,
 			   "uuid item with illegal size %lu!",
 			   (unsigned long)item_size);
 		goto out;
 	}
 	while (item_size) {
 		__le64 data;

 		read_extent_buffer(eb, &data, offset, sizeof(data));
 		if (le64_to_cpu(data) == subid) {
 			ret = 0;
 			break;
 		}
 		offset += sizeof(data);
 		item_size -= sizeof(data);
 	}

 out:
 	btrfs_free_path(path);
 	return ret;
 }

 int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, const u8 *uuid, u8 type,
 			u64 subid_cpu)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_root *uuid_root = fs_info->uuid_root;
 	int ret;
 	struct btrfs_path *path = NULL;
 	struct btrfs_key key;
 	struct extent_buffer *eb;
 	int slot;
 	unsigned long offset;
 	__le64 subid_le;

 	ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
 	if (ret != -ENOENT)
 		return ret;

 	if (WARN_ON_ONCE(!uuid_root)) {
 		ret = -EINVAL;
 		goto out;
 	}

 	btrfs_uuid_to_key(uuid, type, &key);

 	path = btrfs_alloc_path();
 	if (!path) {
 		ret = -ENOMEM;
 		goto out;
 	}

 	ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
 				      sizeof(subid_le));
 	if (ret == 0) {
 		/* Add an item for the type for the first time */
 		eb = path->nodes[0];
 		slot = path->slots[0];
 		offset = btrfs_item_ptr_offset(eb, slot);
 	} else if (ret == -EEXIST) {
 		/*
 		 * An item with that type already exists.
 		 * Extend the item and store the new subid at the end.
 		 */
 		btrfs_extend_item(trans, path, sizeof(subid_le));
 		eb = path->nodes[0];
 		slot = path->slots[0];
 		offset = btrfs_item_ptr_offset(eb, slot);
 		offset += btrfs_item_size(eb, slot) - sizeof(subid_le);
 	} else {
 		btrfs_warn(fs_info,
 			   "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
 			   ret, key.objectid, key.offset, type);
 		goto out;
 	}

 	ret = 0;
 	subid_le = cpu_to_le64(subid_cpu);
 	write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
 	btrfs_mark_buffer_dirty(trans, eb);

 out:
 	btrfs_free_path(path);
 	return ret;
 }

 int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, const u8 *uuid, u8 type,
 			u64 subid)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_root *uuid_root = fs_info->uuid_root;
 	int ret;
 	struct btrfs_path *path = NULL;
 	struct btrfs_key key;
 	struct extent_buffer *eb;
 	int slot;
 	unsigned long offset;
 	u32 item_size;
 	unsigned long move_dst;
 	unsigned long move_src;
 	unsigned long move_len;

 	if (WARN_ON_ONCE(!uuid_root)) {
 		ret = -EINVAL;
 		goto out;
 	}

 	btrfs_uuid_to_key(uuid, type, &key);

 	path = btrfs_alloc_path();
 	if (!path) {
 		ret = -ENOMEM;
 		goto out;
 	}

 	ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
 	if (ret < 0) {
 		btrfs_warn(fs_info, "error %d while searching for uuid item!",
 			   ret);
 		goto out;
 	}
 	if (ret > 0) {
 		ret = -ENOENT;
 		goto out;
 	}

 	eb = path->nodes[0];
 	slot = path->slots[0];
 	offset = btrfs_item_ptr_offset(eb, slot);
 	item_size = btrfs_item_size(eb, slot);
 	if (!IS_ALIGNED(item_size, sizeof(u64))) {
 		btrfs_warn(fs_info, "uuid item with illegal size %lu!",
 			   (unsigned long)item_size);
 		ret = -ENOENT;
 		goto out;
 	}
 	while (item_size) {
 		__le64 read_subid;

 		read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
 		if (le64_to_cpu(read_subid) == subid)
 			break;
 		offset += sizeof(read_subid);
 		item_size -= sizeof(read_subid);
 	}

 	if (!item_size) {
 		ret = -ENOENT;
 		goto out;
 	}

 	item_size = btrfs_item_size(eb, slot);
 	if (item_size == sizeof(subid)) {
 		ret = btrfs_del_item(trans, uuid_root, path);
 		goto out;
 	}

 	move_dst = offset;
 	move_src = offset + sizeof(subid);
 	move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
 	memmove_extent_buffer(eb, move_dst, move_src, move_len);
 	btrfs_truncate_item(trans, path, item_size - sizeof(subid), 1);

 out:
 	btrfs_free_path(path);
 	return ret;
 }

 static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
 			       u64 subid)
 {
 	struct btrfs_trans_handle *trans;
 	int ret;

 	/* 1 - for the uuid item */
 	trans = btrfs_start_transaction(uuid_root, 1);
 	if (IS_ERR(trans)) {
 		ret = PTR_ERR(trans);
 		goto out;
 	}

 	ret = btrfs_uuid_tree_remove(trans, uuid, type, subid);
 	btrfs_end_transaction(trans);

 out:
 	return ret;
 }

 /*
  * Check if there's an matching subvolume for given UUID
  *
  * Return:
  * 0	check succeeded, the entry is not outdated
  * > 0	if the check failed, the caller should remove the entry
  * < 0	if an error occurred
  */
 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
 				       const u8 *uuid, u8 type, u64 subvolid)
 {
 	int ret = 0;
 	struct btrfs_root *subvol_root;

 	if (type != BTRFS_UUID_KEY_SUBVOL &&
 	    type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
 		goto out;

 	subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
 	if (IS_ERR(subvol_root)) {
 		ret = PTR_ERR(subvol_root);
 		if (ret == -ENOENT)
 			ret = 1;
 		goto out;
 	}

 	switch (type) {
 	case BTRFS_UUID_KEY_SUBVOL:
 		if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
 			ret = 1;
 		break;
 	case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
 		if (memcmp(uuid, subvol_root->root_item.received_uuid,
 			   BTRFS_UUID_SIZE))
 			ret = 1;
 		break;
 	}
 	btrfs_put_root(subvol_root);
 out:
 	return ret;
 }

 int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_root *root = fs_info->uuid_root;
 	struct btrfs_key key;
 	struct btrfs_path *path;
 	int ret = 0;
 	struct extent_buffer *leaf;
 	int slot;
 	u32 item_size;
 	unsigned long offset;

 	path = btrfs_alloc_path();
 	if (!path) {
 		ret = -ENOMEM;
 		goto out;
 	}

 	key.objectid = 0;
 	key.type = 0;
 	key.offset = 0;

 again_search_slot:
 	ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
 	if (ret) {
 		if (ret > 0)
 			ret = 0;
 		goto out;
 	}

 	while (1) {
 		if (btrfs_fs_closing(fs_info)) {
 			ret = -EINTR;
 			goto out;
 		}
 		cond_resched();
 		leaf = path->nodes[0];
 		slot = path->slots[0];
 		btrfs_item_key_to_cpu(leaf, &key, slot);

 		if (key.type != BTRFS_UUID_KEY_SUBVOL &&
 		    key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
 			goto skip;

 		offset = btrfs_item_ptr_offset(leaf, slot);
 		item_size = btrfs_item_size(leaf, slot);
 		if (!IS_ALIGNED(item_size, sizeof(u64))) {
 			btrfs_warn(fs_info,
 				   "uuid item with illegal size %lu!",
 				   (unsigned long)item_size);
 			goto skip;
 		}
 		while (item_size) {
 			u8 uuid[BTRFS_UUID_SIZE];
 			__le64 subid_le;
 			u64 subid_cpu;

 			put_unaligned_le64(key.objectid, uuid);
 			put_unaligned_le64(key.offset, uuid + sizeof(u64));
 			read_extent_buffer(leaf, &subid_le, offset,
 					   sizeof(subid_le));
 			subid_cpu = le64_to_cpu(subid_le);
 			ret = btrfs_check_uuid_tree_entry(fs_info, uuid,
 							  key.type, subid_cpu);
 			if (ret < 0)
 				goto out;
 			if (ret > 0) {
 				btrfs_release_path(path);
 				ret = btrfs_uuid_iter_rem(root, uuid, key.type,
 							  subid_cpu);
 				if (ret == 0) {
 					/*
 					 * this might look inefficient, but the
 					 * justification is that it is an
 					 * exception that check_func returns 1,
 					 * and that in the regular case only one
 					 * entry per UUID exists.
 					 */
 					goto again_search_slot;
 				}
 				if (ret < 0 && ret != -ENOENT)
 					goto out;
 				key.offset++;
 				goto again_search_slot;
 			}
 			item_size -= sizeof(subid_le);
 			offset += sizeof(subid_le);
 		}

 skip:
 		ret = btrfs_next_item(root, path);
 		if (ret == 0)
 			continue;
 		else if (ret > 0)
 			ret = 0;
 		break;
 	}

 out:
 	btrfs_free_path(path);
 	return ret;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (C) STRATO AG 2013. All rights reserved.
	*/

	#include <linux/uuid.h>
	#include <asm/unaligned.h>
	#include "messages.h"
	#include "ctree.h"
	#include "transaction.h"
	#include "disk-io.h"
	#include "fs.h"
	#include "accessors.h"
	#include "uuid-tree.h"

	static void btrfs_uuid_to_key(const u8 uuid, u8 type, struct btrfs_key key)
	{
	key->type = type;
	key->objectid = get_unaligned_le64(uuid);
	key->offset = get_unaligned_le64(uuid + sizeof(u64));
	}

	/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
	static int btrfs_uuid_tree_lookup(struct btrfs_root uuid_root, const u8 uuid,
	u8 type, u64 subid)
	{
	int ret;
	struct btrfs_path *path = NULL;
	struct extent_buffer *eb;
	int slot;
	u32 item_size;
	unsigned long offset;
	struct btrfs_key key;

	if (WARN_ON_ONCE(!uuid_root)) {
	ret = -ENOENT;
	goto out;
	}

	path = btrfs_alloc_path();
	if (!path) {
	ret = -ENOMEM;
	goto out;
	}

	btrfs_uuid_to_key(uuid, type, &key);
	ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
	if (ret < 0) {
	goto out;
	} else if (ret > 0) {
	ret = -ENOENT;
	goto out;
	}

	eb = path->nodes[0];
	slot = path->slots[0];
	item_size = btrfs_item_size(eb, slot);
	offset = btrfs_item_ptr_offset(eb, slot);
	ret = -ENOENT;

	if (!IS_ALIGNED(item_size, sizeof(u64))) {
	btrfs_warn(uuid_root->fs_info,
	"uuid item with illegal size %lu!",
	(unsigned long)item_size);
	goto out;
	}
	while (item_size) {
	__le64 data;

	read_extent_buffer(eb, &data, offset, sizeof(data));
	if (le64_to_cpu(data) == subid) {
	ret = 0;
	break;
	}
	offset += sizeof(data);
	item_size -= sizeof(data);
	}

	out:
	btrfs_free_path(path);
	return ret;
	}

	int btrfs_uuid_tree_add(struct btrfs_trans_handle trans, const u8 uuid, u8 type,
	u64 subid_cpu)
	{
	struct btrfs_fs_info *fs_info = trans->fs_info;
	struct btrfs_root *uuid_root = fs_info->uuid_root;
	int ret;
	struct btrfs_path *path = NULL;
	struct btrfs_key key;
	struct extent_buffer *eb;
	int slot;
	unsigned long offset;
	__le64 subid_le;

	ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
	if (ret != -ENOENT)
	return ret;

	if (WARN_ON_ONCE(!uuid_root)) {
	ret = -EINVAL;
	goto out;
	}

	btrfs_uuid_to_key(uuid, type, &key);

	path = btrfs_alloc_path();
	if (!path) {
	ret = -ENOMEM;
	goto out;
	}

	ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
	sizeof(subid_le));
	if (ret == 0) {
	/* Add an item for the type for the first time */
	eb = path->nodes[0];
	slot = path->slots[0];
	offset = btrfs_item_ptr_offset(eb, slot);
	} else if (ret == -EEXIST) {
	/*
	* An item with that type already exists.
	* Extend the item and store the new subid at the end.
	*/
	btrfs_extend_item(trans, path, sizeof(subid_le));
	eb = path->nodes[0];
	slot = path->slots[0];
	offset = btrfs_item_ptr_offset(eb, slot);
	offset += btrfs_item_size(eb, slot) - sizeof(subid_le);
	} else {
	btrfs_warn(fs_info,
	"insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
	ret, key.objectid, key.offset, type);
	goto out;
	}

	ret = 0;
	subid_le = cpu_to_le64(subid_cpu);
	write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
	btrfs_mark_buffer_dirty(trans, eb);

	out:
	btrfs_free_path(path);
	return ret;
	}

	int btrfs_uuid_tree_remove(struct btrfs_trans_handle trans, const u8 uuid, u8 type,
	u64 subid)
	{
	struct btrfs_fs_info *fs_info = trans->fs_info;
	struct btrfs_root *uuid_root = fs_info->uuid_root;
	int ret;
	struct btrfs_path *path = NULL;
	struct btrfs_key key;
	struct extent_buffer *eb;
	int slot;
	unsigned long offset;
	u32 item_size;
	unsigned long move_dst;
	unsigned long move_src;
	unsigned long move_len;

	if (WARN_ON_ONCE(!uuid_root)) {
	ret = -EINVAL;
	goto out;
	}

	btrfs_uuid_to_key(uuid, type, &key);

	path = btrfs_alloc_path();
	if (!path) {
	ret = -ENOMEM;
	goto out;
	}

	ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
	if (ret < 0) {
	btrfs_warn(fs_info, "error %d while searching for uuid item!",
	ret);
	goto out;
	}
	if (ret > 0) {
	ret = -ENOENT;
	goto out;
	}

	eb = path->nodes[0];
	slot = path->slots[0];
	offset = btrfs_item_ptr_offset(eb, slot);
	item_size = btrfs_item_size(eb, slot);
	if (!IS_ALIGNED(item_size, sizeof(u64))) {
	btrfs_warn(fs_info, "uuid item with illegal size %lu!",
	(unsigned long)item_size);
	ret = -ENOENT;
	goto out;
	}
	while (item_size) {
	__le64 read_subid;

	read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
	if (le64_to_cpu(read_subid) == subid)
	break;
	offset += sizeof(read_subid);
	item_size -= sizeof(read_subid);
	}

	if (!item_size) {
	ret = -ENOENT;
	goto out;
	}

	item_size = btrfs_item_size(eb, slot);
	if (item_size == sizeof(subid)) {
	ret = btrfs_del_item(trans, uuid_root, path);
	goto out;
	}

	move_dst = offset;
	move_src = offset + sizeof(subid);
	move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
	memmove_extent_buffer(eb, move_dst, move_src, move_len);
	btrfs_truncate_item(trans, path, item_size - sizeof(subid), 1);

	out:
	btrfs_free_path(path);
	return ret;
	}

	static int btrfs_uuid_iter_rem(struct btrfs_root uuid_root, u8 uuid, u8 type,
	u64 subid)
	{
	struct btrfs_trans_handle *trans;
	int ret;

	/* 1 - for the uuid item */
	trans = btrfs_start_transaction(uuid_root, 1);
	if (IS_ERR(trans)) {
	ret = PTR_ERR(trans);
	goto out;
	}

	ret = btrfs_uuid_tree_remove(trans, uuid, type, subid);
	btrfs_end_transaction(trans);

	out:
	return ret;
	}

	/*
	* Check if there's an matching subvolume for given UUID
	*
	* Return:
	* 0 check succeeded, the entry is not outdated
	* > 0 if the check failed, the caller should remove the entry
	* < 0 if an error occurred
	*/
	static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
	const u8 *uuid, u8 type, u64 subvolid)
	{
	int ret = 0;
	struct btrfs_root *subvol_root;

	if (type != BTRFS_UUID_KEY_SUBVOL &&
	type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
	goto out;

	subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
	if (IS_ERR(subvol_root)) {
	ret = PTR_ERR(subvol_root);
	if (ret == -ENOENT)
	ret = 1;
	goto out;
	}

	switch (type) {
	case BTRFS_UUID_KEY_SUBVOL:
	if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
	ret = 1;
	break;
	case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
	if (memcmp(uuid, subvol_root->root_item.received_uuid,
	BTRFS_UUID_SIZE))
	ret = 1;
	break;
	}
	btrfs_put_root(subvol_root);
	out:
	return ret;
	}

	int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info)
	{
	struct btrfs_root *root = fs_info->uuid_root;
	struct btrfs_key key;
	struct btrfs_path *path;
	int ret = 0;
	struct extent_buffer *leaf;
	int slot;
	u32 item_size;
	unsigned long offset;

	path = btrfs_alloc_path();
	if (!path) {
	ret = -ENOMEM;
	goto out;
	}

	key.objectid = 0;
	key.type = 0;
	key.offset = 0;

	again_search_slot:
	ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
	if (ret) {
	if (ret > 0)
	ret = 0;
	goto out;
	}

	while (1) {
	if (btrfs_fs_closing(fs_info)) {
	ret = -EINTR;
	goto out;
	}
	cond_resched();
	leaf = path->nodes[0];
	slot = path->slots[0];
	btrfs_item_key_to_cpu(leaf, &key, slot);

	if (key.type != BTRFS_UUID_KEY_SUBVOL &&
	key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
	goto skip;

	offset = btrfs_item_ptr_offset(leaf, slot);
	item_size = btrfs_item_size(leaf, slot);
	if (!IS_ALIGNED(item_size, sizeof(u64))) {
	btrfs_warn(fs_info,
	"uuid item with illegal size %lu!",
	(unsigned long)item_size);
	goto skip;
	}
	while (item_size) {
	u8 uuid[BTRFS_UUID_SIZE];
	__le64 subid_le;
	u64 subid_cpu;

	put_unaligned_le64(key.objectid, uuid);
	put_unaligned_le64(key.offset, uuid + sizeof(u64));
	read_extent_buffer(leaf, &subid_le, offset,
	sizeof(subid_le));
	subid_cpu = le64_to_cpu(subid_le);
	ret = btrfs_check_uuid_tree_entry(fs_info, uuid,
	key.type, subid_cpu);
	if (ret < 0)
	goto out;
	if (ret > 0) {
	btrfs_release_path(path);
	ret = btrfs_uuid_iter_rem(root, uuid, key.type,
	subid_cpu);
	if (ret == 0) {
	/*
	* this might look inefficient, but the
	* justification is that it is an
	* exception that check_func returns 1,
	* and that in the regular case only one
	* entry per UUID exists.
	*/
	goto again_search_slot;
	}
	if (ret < 0 && ret != -ENOENT)
	goto out;
	key.offset++;
	goto again_search_slot;
	}
	item_size -= sizeof(subid_le);
	offset += sizeof(subid_le);
	}

	skip:
	ret = btrfs_next_item(root, path);
	if (ret == 0)
	continue;
	else if (ret > 0)
	ret = 0;
	break;
	}

	out:
	btrfs_free_path(path);
	return ret;
	}