blob: 98c08d353a7142408e955f6bae6dc06bcd8f0070 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*/
#include <linux/kernel.h>
#include <log.h>
#include <malloc.h>
#include <memalign.h>
#include "btrfs.h"
#include "disk-io.h"
static const struct btrfs_csum {
u16 size;
const char name[14];
} btrfs_csums[] = {
[BTRFS_CSUM_TYPE_CRC32] = { 4, "crc32c" },
[BTRFS_CSUM_TYPE_XXHASH] = { 8, "xxhash64" },
[BTRFS_CSUM_TYPE_SHA256] = { 32, "sha256" },
[BTRFS_CSUM_TYPE_BLAKE2] = { 32, "blake2" },
};
u16 btrfs_super_csum_size(const struct btrfs_super_block *sb)
{
const u16 csum_type = btrfs_super_csum_type(sb);
return btrfs_csums[csum_type].size;
}
const char *btrfs_super_csum_name(u16 csum_type)
{
return btrfs_csums[csum_type].name;
}
size_t btrfs_super_num_csums(void)
{
return ARRAY_SIZE(btrfs_csums);
}
u16 btrfs_csum_type_size(u16 csum_type)
{
return btrfs_csums[csum_type].size;
}
struct btrfs_path *btrfs_alloc_path(void)
{
struct btrfs_path *path;
path = kzalloc(sizeof(struct btrfs_path), GFP_NOFS);
return path;
}
void btrfs_free_path(struct btrfs_path *p)
{
if (!p)
return;
btrfs_release_path(p);
kfree(p);
}
void btrfs_release_path(struct btrfs_path *p)
{
int i;
for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
if (!p->nodes[i])
continue;
free_extent_buffer(p->nodes[i]);
}
memset(p, 0, sizeof(*p));
}
int __btrfs_comp_keys(struct btrfs_key *a, struct btrfs_key *b)
{
if (a->objectid > b->objectid)
return 1;
if (a->objectid < b->objectid)
return -1;
if (a->type > b->type)
return 1;
if (a->type < b->type)
return -1;
if (a->offset > b->offset)
return 1;
if (a->offset < b->offset)
return -1;
return 0;
}
int btrfs_comp_keys_type(struct btrfs_key *a, struct btrfs_key *b)
{
if (a->objectid > b->objectid)
return 1;
if (a->objectid < b->objectid)
return -1;
if (a->type > b->type)
return 1;
if (a->type < b->type)
return -1;
return 0;
}
/*
* search for key in the extent_buffer. The items start at offset p,
* and they are item_size apart. There are 'max' items in p.
*
* the slot in the array is returned via slot, and it points to
* the place where you would insert key if it is not found in
* the array.
*
* slot may point to max if the key is bigger than all of the keys
*/
static int __generic_bin_search(void *addr, int item_size, struct btrfs_key *key,
int max, int *slot)
{
int low = 0, high = max, mid, ret;
struct btrfs_key *tmp;
while (low < high) {
mid = (low + high) / 2;
tmp = (struct btrfs_key *) ((u8 *) addr + mid*item_size);
ret = __btrfs_comp_keys(tmp, key);
if (ret < 0) {
low = mid + 1;
} else if (ret > 0) {
high = mid;
} else {
*slot = mid;
return 0;
}
}
*slot = low;
return 1;
}
int __btrfs_bin_search(union btrfs_tree_node *p, struct btrfs_key *key,
int *slot)
{
void *addr;
unsigned long size;
if (p->header.level) {
addr = p->node.ptrs;
size = sizeof(struct btrfs_key_ptr);
} else {
addr = p->leaf.items;
size = sizeof(struct btrfs_item);
}
return __generic_bin_search(addr, size, key, p->header.nritems, slot);
}
static void clear_path(struct __btrfs_path *p)
{
int i;
for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
p->nodes[i] = NULL;
p->slots[i] = 0;
}
}
void __btrfs_free_path(struct __btrfs_path *p)
{
int i;
for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
if (p->nodes[i])
free(p->nodes[i]);
}
clear_path(p);
}
static int read_tree_node(u64 physical, union btrfs_tree_node **buf)
{
ALLOC_CACHE_ALIGN_BUFFER(struct btrfs_header, hdr,
sizeof(struct btrfs_header));
unsigned long size, offset = sizeof(*hdr);
union btrfs_tree_node *res;
u32 i;
if (!btrfs_devread(physical, sizeof(*hdr), hdr))
return -1;
btrfs_header_to_cpu(hdr);
if (hdr->level)
size = sizeof(struct btrfs_node)
+ hdr->nritems * sizeof(struct btrfs_key_ptr);
else
size = btrfs_info.sb.nodesize;
res = malloc_cache_aligned(size);
if (!res) {
debug("%s: malloc failed\n", __func__);
return -1;
}
if (!btrfs_devread(physical + offset, size - offset,
((u8 *) res) + offset)) {
free(res);
return -1;
}
memcpy(&res->header, hdr, sizeof(*hdr));
if (hdr->level)
for (i = 0; i < hdr->nritems; ++i)
btrfs_key_ptr_to_cpu(&res->node.ptrs[i]);
else
for (i = 0; i < hdr->nritems; ++i)
btrfs_item_to_cpu(&res->leaf.items[i]);
*buf = res;
return 0;
}
int btrfs_search_tree(const struct __btrfs_root *root, struct btrfs_key *key,
struct __btrfs_path *p)
{
u8 lvl, prev_lvl;
int i, slot, ret;
u64 logical, physical;
union btrfs_tree_node *buf;
clear_path(p);
logical = root->bytenr;
for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
physical = btrfs_map_logical_to_physical(logical);
if (physical == -1ULL)
goto err;
if (read_tree_node(physical, &buf))
goto err;
lvl = buf->header.level;
if (i && prev_lvl != lvl + 1) {
printf("%s: invalid level in header at %llu\n",
__func__, logical);
goto err;
}
prev_lvl = lvl;
ret = __btrfs_bin_search(buf, key, &slot);
if (ret < 0)
goto err;
if (ret && slot > 0 && lvl)
slot -= 1;
p->slots[lvl] = slot;
p->nodes[lvl] = buf;
if (lvl) {
logical = buf->node.ptrs[slot].blockptr;
} else {
/*
* The path might be invalid if:
* cur leaf max < searched value < next leaf min
*
* Jump to the next valid element if it exists.
*/
if (slot >= buf->header.nritems)
if (btrfs_next_slot(p) < 0)
goto err;
break;
}
}
return 0;
err:
__btrfs_free_path(p);
return -1;
}
static int jump_leaf(struct __btrfs_path *path, int dir)
{
struct __btrfs_path p;
u32 slot;
int level = 1, from_level, i;
dir = dir >= 0 ? 1 : -1;
p = *path;
while (level < BTRFS_MAX_LEVEL) {
if (!p.nodes[level])
return 1;
slot = p.slots[level];
if ((dir > 0 && slot + dir >= p.nodes[level]->header.nritems)
|| (dir < 0 && !slot))
level++;
else
break;
}
if (level == BTRFS_MAX_LEVEL)
return 1;
p.slots[level] = slot + dir;
level--;
from_level = level;
while (level >= 0) {
u64 logical, physical;
slot = p.slots[level + 1];
logical = p.nodes[level + 1]->node.ptrs[slot].blockptr;
physical = btrfs_map_logical_to_physical(logical);
if (physical == -1ULL)
goto err;
if (read_tree_node(physical, &p.nodes[level]))
goto err;
if (dir > 0)
p.slots[level] = 0;
else
p.slots[level] = p.nodes[level]->header.nritems - 1;
level--;
}
/* Free rewritten nodes in path */
for (i = 0; i <= from_level; ++i)
free(path->nodes[i]);
*path = p;
return 0;
err:
/* Free rewritten nodes in p */
for (i = level + 1; i <= from_level; ++i)
free(p.nodes[i]);
return -1;
}
int btrfs_prev_slot(struct __btrfs_path *p)
{
if (!p->slots[0])
return jump_leaf(p, -1);
p->slots[0]--;
return 0;
}
int btrfs_next_slot(struct __btrfs_path *p)
{
struct btrfs_leaf *leaf = &p->nodes[0]->leaf;
if (p->slots[0] + 1 >= leaf->header.nritems)
return jump_leaf(p, 1);
p->slots[0]++;
return 0;
}
int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
{
if (k1->objectid > k2->objectid)
return 1;
if (k1->objectid < k2->objectid)
return -1;
if (k1->type > k2->type)
return 1;
if (k1->type < k2->type)
return -1;
if (k1->offset > k2->offset)
return 1;
if (k1->offset < k2->offset)
return -1;
return 0;
}
static int btrfs_comp_keys(struct btrfs_disk_key *disk,
const struct btrfs_key *k2)
{
struct btrfs_key k1;
btrfs_disk_key_to_cpu(&k1, disk);
return btrfs_comp_cpu_keys(&k1, k2);
}
enum btrfs_tree_block_status
btrfs_check_node(struct btrfs_fs_info *fs_info,
struct btrfs_disk_key *parent_key, struct extent_buffer *buf)
{
int i;
struct btrfs_key cpukey;
struct btrfs_disk_key key;
u32 nritems = btrfs_header_nritems(buf);
enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
if (nritems == 0 || nritems > BTRFS_NODEPTRS_PER_BLOCK(fs_info))
goto fail;
ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
if (parent_key && parent_key->type) {
btrfs_node_key(buf, &key, 0);
if (memcmp(parent_key, &key, sizeof(key)))
goto fail;
}
ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
for (i = 0; nritems > 1 && i < nritems - 2; i++) {
btrfs_node_key(buf, &key, i);
btrfs_node_key_to_cpu(buf, &cpukey, i + 1);
if (btrfs_comp_keys(&key, &cpukey) >= 0)
goto fail;
}
return BTRFS_TREE_BLOCK_CLEAN;
fail:
return ret;
}
enum btrfs_tree_block_status
btrfs_check_leaf(struct btrfs_fs_info *fs_info,
struct btrfs_disk_key *parent_key, struct extent_buffer *buf)
{
int i;
struct btrfs_key cpukey;
struct btrfs_disk_key key;
u32 nritems = btrfs_header_nritems(buf);
enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
if (nritems * sizeof(struct btrfs_item) > buf->len) {
fprintf(stderr, "invalid number of items %llu\n",
(unsigned long long)buf->start);
goto fail;
}
if (btrfs_header_level(buf) != 0) {
ret = BTRFS_TREE_BLOCK_INVALID_LEVEL;
fprintf(stderr, "leaf is not a leaf %llu\n",
(unsigned long long)btrfs_header_bytenr(buf));
goto fail;
}
if (btrfs_leaf_free_space(buf) < 0) {
ret = BTRFS_TREE_BLOCK_INVALID_FREE_SPACE;
fprintf(stderr, "leaf free space incorrect %llu %d\n",
(unsigned long long)btrfs_header_bytenr(buf),
btrfs_leaf_free_space(buf));
goto fail;
}
if (nritems == 0)
return BTRFS_TREE_BLOCK_CLEAN;
btrfs_item_key(buf, &key, 0);
if (parent_key && parent_key->type &&
memcmp(parent_key, &key, sizeof(key))) {
ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
fprintf(stderr, "leaf parent key incorrect %llu\n",
(unsigned long long)btrfs_header_bytenr(buf));
goto fail;
}
for (i = 0; nritems > 1 && i < nritems - 1; i++) {
btrfs_item_key(buf, &key, i);
btrfs_item_key_to_cpu(buf, &cpukey, i + 1);
if (btrfs_comp_keys(&key, &cpukey) >= 0) {
ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
fprintf(stderr, "bad key ordering %d %d\n", i, i+1);
goto fail;
}
if (btrfs_item_offset_nr(buf, i) !=
btrfs_item_end_nr(buf, i + 1)) {
ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
fprintf(stderr, "incorrect offsets %u %u\n",
btrfs_item_offset_nr(buf, i),
btrfs_item_end_nr(buf, i + 1));
goto fail;
}
if (i == 0 && btrfs_item_end_nr(buf, i) !=
BTRFS_LEAF_DATA_SIZE(fs_info)) {
ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
fprintf(stderr, "bad item end %u wanted %u\n",
btrfs_item_end_nr(buf, i),
(unsigned)BTRFS_LEAF_DATA_SIZE(fs_info));
goto fail;
}
}
for (i = 0; i < nritems; i++) {
if (btrfs_item_end_nr(buf, i) >
BTRFS_LEAF_DATA_SIZE(fs_info)) {
btrfs_item_key(buf, &key, 0);
ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
fprintf(stderr, "slot end outside of leaf %llu > %llu\n",
(unsigned long long)btrfs_item_end_nr(buf, i),
(unsigned long long)BTRFS_LEAF_DATA_SIZE(
fs_info));
goto fail;
}
}
return BTRFS_TREE_BLOCK_CLEAN;
fail:
return ret;
}
static int noinline check_block(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, int level)
{
struct btrfs_disk_key key;
struct btrfs_disk_key *key_ptr = NULL;
struct extent_buffer *parent;
enum btrfs_tree_block_status ret;
if (path->nodes[level + 1]) {
parent = path->nodes[level + 1];
btrfs_node_key(parent, &key, path->slots[level + 1]);
key_ptr = &key;
}
if (level == 0)
ret = btrfs_check_leaf(fs_info, key_ptr, path->nodes[0]);
else
ret = btrfs_check_node(fs_info, key_ptr, path->nodes[level]);
if (ret == BTRFS_TREE_BLOCK_CLEAN)
return 0;
return -EIO;
}
/*
* search for key in the extent_buffer. The items start at offset p,
* and they are item_size apart. There are 'max' items in p.
*
* the slot in the array is returned via slot, and it points to
* the place where you would insert key if it is not found in
* the array.
*
* slot may point to max if the key is bigger than all of the keys
*/
static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
int item_size, const struct btrfs_key *key,
int max, int *slot)
{
int low = 0;
int high = max;
int mid;
int ret;
unsigned long offset;
struct btrfs_disk_key *tmp;
while(low < high) {
mid = (low + high) / 2;
offset = p + mid * item_size;
tmp = (struct btrfs_disk_key *)(eb->data + offset);
ret = btrfs_comp_keys(tmp, key);
if (ret < 0)
low = mid + 1;
else if (ret > 0)
high = mid;
else {
*slot = mid;
return 0;
}
}
*slot = low;
return 1;
}
/*
* simple bin_search frontend that does the right thing for
* leaves vs nodes
*/
int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
int *slot)
{
if (btrfs_header_level(eb) == 0)
return generic_bin_search(eb,
offsetof(struct btrfs_leaf, items),
sizeof(struct btrfs_item),
key, btrfs_header_nritems(eb),
slot);
else
return generic_bin_search(eb,
offsetof(struct btrfs_node, ptrs),
sizeof(struct btrfs_key_ptr),
key, btrfs_header_nritems(eb),
slot);
}
struct extent_buffer *read_node_slot(struct btrfs_fs_info *fs_info,
struct extent_buffer *parent, int slot)
{
struct extent_buffer *ret;
int level = btrfs_header_level(parent);
if (slot < 0)
return NULL;
if (slot >= btrfs_header_nritems(parent))
return NULL;
if (level == 0)
return NULL;
ret = read_tree_block(fs_info, btrfs_node_blockptr(parent, slot),
btrfs_node_ptr_generation(parent, slot));
if (!extent_buffer_uptodate(ret))
return ERR_PTR(-EIO);
if (btrfs_header_level(ret) != level - 1) {
error("child eb corrupted: parent bytenr=%llu item=%d parent level=%d child level=%d",
btrfs_header_bytenr(parent), slot,
btrfs_header_level(parent), btrfs_header_level(ret));
free_extent_buffer(ret);
return ERR_PTR(-EIO);
}
return ret;
}
int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *found_path,
u64 iobjectid, u64 ioff, u8 key_type,
struct btrfs_key *found_key)
{
int ret;
struct btrfs_key key;
struct extent_buffer *eb;
struct btrfs_path *path;
key.type = key_type;
key.objectid = iobjectid;
key.offset = ioff;
if (found_path == NULL) {
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
} else
path = found_path;
ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
if ((ret < 0) || (found_key == NULL))
goto out;
eb = path->nodes[0];
if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(fs_root, path);
if (ret)
goto out;
eb = path->nodes[0];
}
btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
if (found_key->type != key.type ||
found_key->objectid != key.objectid) {
ret = 1;
goto out;
}
out:
if (path != found_path)
btrfs_free_path(path);
return ret;
}
/*
* look for key in the tree. path is filled in with nodes along the way
* if key is found, we return zero and you can find the item in the leaf
* level of the path (level 0)
*
* If the key isn't found, the path points to the slot where it should
* be inserted, and 1 is returned. If there are other errors during the
* search a negative error number is returned.
*
* if ins_len > 0, nodes and leaves will be split as we walk down the
* tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
* possible)
*
* NOTE: This version has no COW ability, thus we expect trans == NULL,
* ins_len == 0 and cow == 0.
*/
int btrfs_search_slot(struct btrfs_trans_handle *trans,
struct btrfs_root *root, const struct btrfs_key *key,
struct btrfs_path *p, int ins_len, int cow)
{
struct extent_buffer *b;
int slot;
int ret;
int level;
struct btrfs_fs_info *fs_info = root->fs_info;
u8 lowest_level = 0;
assert(trans == NULL && ins_len == 0 && cow == 0);
lowest_level = p->lowest_level;
WARN_ON(lowest_level && ins_len > 0);
WARN_ON(p->nodes[0] != NULL);
b = root->node;
extent_buffer_get(b);
while (b) {
level = btrfs_header_level(b);
/*
if (cow) {
int wret;
wret = btrfs_cow_block(trans, root, b,
p->nodes[level + 1],
p->slots[level + 1],
&b);
if (wret) {
free_extent_buffer(b);
return wret;
}
}
*/
BUG_ON(!cow && ins_len);
if (level != btrfs_header_level(b))
WARN_ON(1);
level = btrfs_header_level(b);
p->nodes[level] = b;
ret = check_block(fs_info, p, level);
if (ret)
return -1;
ret = btrfs_bin_search(b, key, &slot);
if (level != 0) {
if (ret && slot > 0)
slot -= 1;
p->slots[level] = slot;
/*
if ((p->search_for_split || ins_len > 0) &&
btrfs_header_nritems(b) >=
BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) {
int sret = split_node(trans, root, p, level);
BUG_ON(sret > 0);
if (sret)
return sret;
b = p->nodes[level];
slot = p->slots[level];
} else if (ins_len < 0) {
int sret = balance_level(trans, root, p,
level);
if (sret)
return sret;
b = p->nodes[level];
if (!b) {
btrfs_release_path(p);
goto again;
}
slot = p->slots[level];
BUG_ON(btrfs_header_nritems(b) == 1);
}
*/
/* this is only true while dropping a snapshot */
if (level == lowest_level)
break;
b = read_node_slot(fs_info, b, slot);
if (!extent_buffer_uptodate(b))
return -EIO;
} else {
p->slots[level] = slot;
/*
if (ins_len > 0 &&
ins_len > btrfs_leaf_free_space(b)) {
int sret = split_leaf(trans, root, key,
p, ins_len, ret == 0);
BUG_ON(sret > 0);
if (sret)
return sret;
}
*/
return ret;
}
}
return 1;
}
/*
* Helper to use instead of search slot if no exact match is needed but
* instead the next or previous item should be returned.
* When find_higher is true, the next higher item is returned, the next lower
* otherwise.
* When return_any and find_higher are both true, and no higher item is found,
* return the next lower instead.
* When return_any is true and find_higher is false, and no lower item is found,
* return the next higher instead.
* It returns 0 if any item is found, 1 if none is found (tree empty), and
* < 0 on error
*/
int btrfs_search_slot_for_read(struct btrfs_root *root,
const struct btrfs_key *key,
struct btrfs_path *p, int find_higher,
int return_any)
{
int ret;
struct extent_buffer *leaf;
again:
ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
if (ret <= 0)
return ret;
/*
* A return value of 1 means the path is at the position where the item
* should be inserted. Normally this is the next bigger item, but in
* case the previous item is the last in a leaf, path points to the
* first free slot in the previous leaf, i.e. at an invalid item.
*/
leaf = p->nodes[0];
if (find_higher) {
if (p->slots[0] >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, p);
if (ret <= 0)
return ret;
if (!return_any)
return 1;
/*
* No higher item found, return the next lower instead
*/
return_any = 0;
find_higher = 0;
btrfs_release_path(p);
goto again;
}
} else {
if (p->slots[0] == 0) {
ret = btrfs_prev_leaf(root, p);
if (ret < 0)
return ret;
if (!ret) {
leaf = p->nodes[0];
if (p->slots[0] == btrfs_header_nritems(leaf))
p->slots[0]--;
return 0;
}
if (!return_any)
return 1;
/*
* No lower item found, return the next higher instead
*/
return_any = 0;
find_higher = 1;
btrfs_release_path(p);
goto again;
} else {
--p->slots[0];
}
}
return 0;
}
/*
* how many bytes are required to store the items in a leaf. start
* and nr indicate which items in the leaf to check. This totals up the
* space used both by the item structs and the item data
*/
static int leaf_space_used(struct extent_buffer *l, int start, int nr)
{
int data_len;
int nritems = btrfs_header_nritems(l);
int end = min(nritems, start + nr) - 1;
if (!nr)
return 0;
data_len = btrfs_item_end_nr(l, start);
data_len = data_len - btrfs_item_offset_nr(l, end);
data_len += sizeof(struct btrfs_item) * nr;
WARN_ON(data_len < 0);
return data_len;
}
/*
* The space between the end of the leaf items and
* the start of the leaf data. IOW, how much room
* the leaf has left for both items and data
*/
int btrfs_leaf_free_space(struct extent_buffer *leaf)
{
int nritems = btrfs_header_nritems(leaf);
u32 leaf_data_size;
int ret;
BUG_ON(leaf->fs_info && leaf->fs_info->nodesize != leaf->len);
leaf_data_size = __BTRFS_LEAF_DATA_SIZE(leaf->len);
ret = leaf_data_size - leaf_space_used(leaf, 0 ,nritems);
if (ret < 0) {
printk("leaf free space ret %d, leaf data size %u, used %d nritems %d\n",
ret, leaf_data_size, leaf_space_used(leaf, 0, nritems),
nritems);
}
return ret;
}
/*
* walk up the tree as far as required to find the previous leaf.
* returns 0 if it found something or 1 if there are no lesser leaves.
* returns < 0 on io errors.
*/
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
{
int slot;
int level = 1;
struct extent_buffer *c;
struct extent_buffer *next = NULL;
struct btrfs_fs_info *fs_info = root->fs_info;
while(level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
return 1;
slot = path->slots[level];
c = path->nodes[level];
if (slot == 0) {
level++;
if (level == BTRFS_MAX_LEVEL)
return 1;
continue;
}
slot--;
next = read_node_slot(fs_info, c, slot);
if (!extent_buffer_uptodate(next)) {
if (IS_ERR(next))
return PTR_ERR(next);
return -EIO;
}
break;
}
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
free_extent_buffer(c);
slot = btrfs_header_nritems(next);
if (slot != 0)
slot--;
path->nodes[level] = next;
path->slots[level] = slot;
if (!level)
break;
next = read_node_slot(fs_info, next, slot);
if (!extent_buffer_uptodate(next)) {
if (IS_ERR(next))
return PTR_ERR(next);
return -EIO;
}
}
return 0;
}
/*
* Walk up the tree as far as necessary to find the next sibling tree block.
* More generic version of btrfs_next_leaf(), as it could find sibling nodes
* if @path->lowest_level is not 0.
*
* returns 0 if it found something or 1 if there are no greater leaves.
* returns < 0 on io errors.
*/
int btrfs_next_sibling_tree_block(struct btrfs_fs_info *fs_info,
struct btrfs_path *path)
{
int slot;
int level = path->lowest_level + 1;
struct extent_buffer *c;
struct extent_buffer *next = NULL;
BUG_ON(path->lowest_level + 1 >= BTRFS_MAX_LEVEL);
do {
if (!path->nodes[level])
return 1;
slot = path->slots[level] + 1;
c = path->nodes[level];
if (slot >= btrfs_header_nritems(c)) {
level++;
if (level == BTRFS_MAX_LEVEL)
return 1;
continue;
}
next = read_node_slot(fs_info, c, slot);
if (!extent_buffer_uptodate(next))
return -EIO;
break;
} while (level < BTRFS_MAX_LEVEL);
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
free_extent_buffer(c);
path->nodes[level] = next;
path->slots[level] = 0;
if (level == path->lowest_level)
break;
next = read_node_slot(fs_info, next, 0);
if (!extent_buffer_uptodate(next))
return -EIO;
}
return 0;
}
int btrfs_previous_item(struct btrfs_root *root,
struct btrfs_path *path, u64 min_objectid,
int type)
{
struct btrfs_key found_key;
struct extent_buffer *leaf;
u32 nritems;
int ret;
while(1) {
if (path->slots[0] == 0) {
ret = btrfs_prev_leaf(root, path);
if (ret != 0)
return ret;
} else {
path->slots[0]--;
}
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
if (nritems == 0)
return 1;
if (path->slots[0] == nritems)
path->slots[0]--;
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.objectid < min_objectid)
break;
if (found_key.type == type)
return 0;
if (found_key.objectid == min_objectid &&
found_key.type < type)
break;
}
return 1;
}