[linux-block.git] / fs / btrfs / uuid-tree.c

// 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 "print-tree.h"
#include "fs.h"
#include "accessors.h"
#include "uuid-tree.h"

static void btrfs_uuid_to_key(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, 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, 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(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(eb);

out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, 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(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,
				       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;
}
Commit	Line	Data
c1d7c514	1	// SPDX-License-Identifier: GPL-2.0
07b30a49 SB	2	/*
07b30a49 SB	3	* Copyright (C) STRATO AG 2013. All rights reserved.
07b30a49	4	*/
c1d7c514	5
07b30a49 SB	6	#include <linux/uuid.h>
07b30a49 SB	7	#include <asm/unaligned.h>
9b569ea0	8	#include "messages.h"
07b30a49 SB	9	#include "ctree.h"
	10	#include "transaction.h"
	11	#include "disk-io.h"
	12	#include "print-tree.h"
c7f13d42	13	#include "fs.h"
07e81dc9	14	#include "accessors.h"
c7a03b52	15	#include "uuid-tree.h"
07b30a49 SB	16
	17	static void btrfs_uuid_to_key(u8 uuid, u8 type, struct btrfs_key key)
	18	{
	19	key->type = type;
	20	key->objectid = get_unaligned_le64(uuid);
	21	key->offset = get_unaligned_le64(uuid + sizeof(u64));
	22	}
	23
	24	/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
	25	static int btrfs_uuid_tree_lookup(struct btrfs_root uuid_root, u8 uuid,
	26	u8 type, u64 subid)
	27	{
	28	int ret;
	29	struct btrfs_path *path = NULL;
	30	struct extent_buffer *eb;
	31	int slot;
	32	u32 item_size;
	33	unsigned long offset;
	34	struct btrfs_key key;
	35
	36	if (WARN_ON_ONCE(!uuid_root)) {
	37	ret = -ENOENT;
	38	goto out;
	39	}
	40
	41	path = btrfs_alloc_path();
	42	if (!path) {
	43	ret = -ENOMEM;
	44	goto out;
	45	}
	46
	47	btrfs_uuid_to_key(uuid, type, &key);
	48	ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
	49	if (ret < 0) {
	50	goto out;
	51	} else if (ret > 0) {
	52	ret = -ENOENT;
	53	goto out;
	54	}
	55
	56	eb = path->nodes[0];
	57	slot = path->slots[0];
3212fa14	58	item_size = btrfs_item_size(eb, slot);
07b30a49 SB	59	offset = btrfs_item_ptr_offset(eb, slot);
	60	ret = -ENOENT;
	61
	62	if (!IS_ALIGNED(item_size, sizeof(u64))) {
5d163e0e JM	63	btrfs_warn(uuid_root->fs_info,
	64	"uuid item with illegal size %lu!",
	65	(unsigned long)item_size);
07b30a49 SB	66	goto out;
	67	}
	68	while (item_size) {
	69	__le64 data;
	70
	71	read_extent_buffer(eb, &data, offset, sizeof(data));
	72	if (le64_to_cpu(data) == subid) {
	73	ret = 0;
	74	break;
	75	}
	76	offset += sizeof(data);
	77	item_size -= sizeof(data);
	78	}
	79
	80	out:
	81	btrfs_free_path(path);
	82	return ret;
	83	}
	84
cdb345a8	85	int btrfs_uuid_tree_add(struct btrfs_trans_handle trans, u8 uuid, u8 type,
07b30a49 SB	86	u64 subid_cpu)
07b30a49 SB	87	{
cdb345a8	88	struct btrfs_fs_info *fs_info = trans->fs_info;
6bccf3ab	89	struct btrfs_root *uuid_root = fs_info->uuid_root;
07b30a49 SB	90	int ret;
	91	struct btrfs_path *path = NULL;
	92	struct btrfs_key key;
	93	struct extent_buffer *eb;
	94	int slot;
	95	unsigned long offset;
	96	__le64 subid_le;
	97
	98	ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
	99	if (ret != -ENOENT)
	100	return ret;
	101
	102	if (WARN_ON_ONCE(!uuid_root)) {
	103	ret = -EINVAL;
	104	goto out;
	105	}
	106
	107	btrfs_uuid_to_key(uuid, type, &key);
	108
	109	path = btrfs_alloc_path();
	110	if (!path) {
	111	ret = -ENOMEM;
	112	goto out;
	113	}
	114
	115	ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
	116	sizeof(subid_le));
	117	if (ret >= 0) {
	118	/* Add an item for the type for the first time */
	119	eb = path->nodes[0];
	120	slot = path->slots[0];
	121	offset = btrfs_item_ptr_offset(eb, slot);
	122	} else if (ret == -EEXIST) {
	123	/*
	124	* An item with that type already exists.
	125	* Extend the item and store the new subid at the end.
	126	*/
c71dd880	127	btrfs_extend_item(path, sizeof(subid_le));
07b30a49 SB	128	eb = path->nodes[0];
	129	slot = path->slots[0];
	130	offset = btrfs_item_ptr_offset(eb, slot);
3212fa14	131	offset += btrfs_item_size(eb, slot) - sizeof(subid_le);
e8baf7ab	132	} else {
6bccf3ab	133	btrfs_warn(fs_info,
5d163e0e	134	"insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
cc7c7714	135	ret, key.objectid, key.offset, type);
07b30a49 SB	136	goto out;
	137	}
	138
	139	ret = 0;
	140	subid_le = cpu_to_le64(subid_cpu);
	141	write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
	142	btrfs_mark_buffer_dirty(eb);
	143
	144	out:
	145	btrfs_free_path(path);
	146	return ret;
	147	}
	148
d1957791	149	int btrfs_uuid_tree_remove(struct btrfs_trans_handle trans, u8 uuid, u8 type,
07b30a49 SB	150	u64 subid)
07b30a49 SB	151	{
d1957791	152	struct btrfs_fs_info *fs_info = trans->fs_info;
6bccf3ab	153	struct btrfs_root *uuid_root = fs_info->uuid_root;
07b30a49 SB	154	int ret;
	155	struct btrfs_path *path = NULL;
	156	struct btrfs_key key;
	157	struct extent_buffer *eb;
	158	int slot;
	159	unsigned long offset;
	160	u32 item_size;
	161	unsigned long move_dst;
	162	unsigned long move_src;
	163	unsigned long move_len;
	164
	165	if (WARN_ON_ONCE(!uuid_root)) {
	166	ret = -EINVAL;
	167	goto out;
	168	}
	169
	170	btrfs_uuid_to_key(uuid, type, &key);
	171
	172	path = btrfs_alloc_path();
	173	if (!path) {
	174	ret = -ENOMEM;
	175	goto out;
	176	}
	177
	178	ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
	179	if (ret < 0) {
0b246afa JM	180	btrfs_warn(fs_info, "error %d while searching for uuid item!",
0b246afa JM	181	ret);
07b30a49 SB	182	goto out;
	183	}
	184	if (ret > 0) {
	185	ret = -ENOENT;
	186	goto out;
	187	}
	188
	189	eb = path->nodes[0];
	190	slot = path->slots[0];
	191	offset = btrfs_item_ptr_offset(eb, slot);
3212fa14	192	item_size = btrfs_item_size(eb, slot);
07b30a49	193	if (!IS_ALIGNED(item_size, sizeof(u64))) {
0b246afa	194	btrfs_warn(fs_info, "uuid item with illegal size %lu!",
5d163e0e	195	(unsigned long)item_size);
07b30a49 SB	196	ret = -ENOENT;
	197	goto out;
	198	}
	199	while (item_size) {
	200	__le64 read_subid;
	201
	202	read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
	203	if (le64_to_cpu(read_subid) == subid)
	204	break;
	205	offset += sizeof(read_subid);
	206	item_size -= sizeof(read_subid);
	207	}
	208
	209	if (!item_size) {
	210	ret = -ENOENT;
	211	goto out;
	212	}
	213
3212fa14	214	item_size = btrfs_item_size(eb, slot);
07b30a49 SB	215	if (item_size == sizeof(subid)) {
	216	ret = btrfs_del_item(trans, uuid_root, path);
	217	goto out;
	218	}
	219
	220	move_dst = offset;
	221	move_src = offset + sizeof(subid);
	222	move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
	223	memmove_extent_buffer(eb, move_dst, move_src, move_len);
78ac4f9e	224	btrfs_truncate_item(path, item_size - sizeof(subid), 1);
07b30a49 SB	225
	226	out:
	227	btrfs_free_path(path);
	228	return ret;
	229	}
70f80175 SB	230
	231	static int btrfs_uuid_iter_rem(struct btrfs_root uuid_root, u8 uuid, u8 type,
	232	u64 subid)
	233	{
	234	struct btrfs_trans_handle *trans;
	235	int ret;
	236
	237	/* 1 - for the uuid item */
	238	trans = btrfs_start_transaction(uuid_root, 1);
	239	if (IS_ERR(trans)) {
	240	ret = PTR_ERR(trans);
	241	goto out;
	242	}
	243
d1957791	244	ret = btrfs_uuid_tree_remove(trans, uuid, type, subid);
3a45bb20	245	btrfs_end_transaction(trans);
70f80175 SB	246
	247	out:
	248	return ret;
	249	}
	250
560b7a4a NB	251	/*
	252	* Check if there's an matching subvolume for given UUID
	253	*
	254	* Return:
	255	* 0 check succeeded, the entry is not outdated
	256	* > 0 if the check failed, the caller should remove the entry
	257	* < 0 if an error occurred
	258	*/
	259	static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
	260	u8 *uuid, u8 type, u64 subvolid)
	261	{
560b7a4a NB	262	int ret = 0;
	263	struct btrfs_root *subvol_root;
	264
	265	if (type != BTRFS_UUID_KEY_SUBVOL &&
	266	type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
	267	goto out;
	268
56e9357a	269	subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
560b7a4a NB	270	if (IS_ERR(subvol_root)) {
	271	ret = PTR_ERR(subvol_root);
	272	if (ret == -ENOENT)
	273	ret = 1;
	274	goto out;
	275	}
	276
	277	switch (type) {
	278	case BTRFS_UUID_KEY_SUBVOL:
	279	if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
	280	ret = 1;
	281	break;
	282	case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
	283	if (memcmp(uuid, subvol_root->root_item.received_uuid,
	284	BTRFS_UUID_SIZE))
	285	ret = 1;
	286	break;
	287	}
	288	btrfs_put_root(subvol_root);
	289	out:
	290	return ret;
	291	}
	292
	293	int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info)
70f80175 SB	294	{
	295	struct btrfs_root *root = fs_info->uuid_root;
	296	struct btrfs_key key;
70f80175 SB	297	struct btrfs_path *path;
	298	int ret = 0;
	299	struct extent_buffer *leaf;
	300	int slot;
	301	u32 item_size;
	302	unsigned long offset;
	303
	304	path = btrfs_alloc_path();
	305	if (!path) {
	306	ret = -ENOMEM;
	307	goto out;
	308	}
	309
	310	key.objectid = 0;
	311	key.type = 0;
	312	key.offset = 0;
70f80175 SB	313
70f80175 SB	314	again_search_slot:
7c829b72	315	ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
70f80175 SB	316	if (ret) {
	317	if (ret > 0)
	318	ret = 0;
	319	goto out;
	320	}
	321
	322	while (1) {
c94bec2c JB	323	if (btrfs_fs_closing(fs_info)) {
	324	ret = -EINTR;
	325	goto out;
	326	}
70f80175 SB	327	cond_resched();
	328	leaf = path->nodes[0];
	329	slot = path->slots[0];
	330	btrfs_item_key_to_cpu(leaf, &key, slot);
	331
	332	if (key.type != BTRFS_UUID_KEY_SUBVOL &&
	333	key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
	334	goto skip;
	335
	336	offset = btrfs_item_ptr_offset(leaf, slot);
3212fa14	337	item_size = btrfs_item_size(leaf, slot);
70f80175	338	if (!IS_ALIGNED(item_size, sizeof(u64))) {
5d163e0e JM	339	btrfs_warn(fs_info,
	340	"uuid item with illegal size %lu!",
	341	(unsigned long)item_size);
70f80175 SB	342	goto skip;
	343	}
	344	while (item_size) {
	345	u8 uuid[BTRFS_UUID_SIZE];
	346	__le64 subid_le;
	347	u64 subid_cpu;
	348
	349	put_unaligned_le64(key.objectid, uuid);
	350	put_unaligned_le64(key.offset, uuid + sizeof(u64));
	351	read_extent_buffer(leaf, &subid_le, offset,
	352	sizeof(subid_le));
	353	subid_cpu = le64_to_cpu(subid_le);
560b7a4a NB	354	ret = btrfs_check_uuid_tree_entry(fs_info, uuid,
560b7a4a NB	355	key.type, subid_cpu);
70f80175 SB	356	if (ret < 0)
	357	goto out;
	358	if (ret > 0) {
	359	btrfs_release_path(path);
	360	ret = btrfs_uuid_iter_rem(root, uuid, key.type,
	361	subid_cpu);
	362	if (ret == 0) {
	363	/*
	364	* this might look inefficient, but the
	365	* justification is that it is an
	366	* exception that check_func returns 1,
	367	* and that in the regular case only one
	368	* entry per UUID exists.
	369	*/
	370	goto again_search_slot;
	371	}
	372	if (ret < 0 && ret != -ENOENT)
	373	goto out;
714cd3e8 JB	374	key.offset++;
714cd3e8 JB	375	goto again_search_slot;
70f80175 SB	376	}
	377	item_size -= sizeof(subid_le);
	378	offset += sizeof(subid_le);
	379	}
	380
	381	skip:
	382	ret = btrfs_next_item(root, path);
	383	if (ret == 0)
	384	continue;
	385	else if (ret > 0)
	386	ret = 0;
	387	break;
	388	}
	389
	390	out:
	391	btrfs_free_path(path);
73ba39ab	392	return ret;
70f80175	393	}