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fs: btrfs: Add single-device read-only BTRFS implementation

This adds the proper implementation for the BTRFS filesystem.
The implementation currently supports only read-only mode and
the filesystem can be only on a single device.

Checksums of data chunks is unimplemented.

Compression is implemented (ZLIB + LZO).

Signed-off-by: Marek Behun <marek.behun@nic.cz>

 create mode 100644 fs/btrfs/btrfs.h
 create mode 100644 fs/btrfs/chunk-map.c
 create mode 100644 fs/btrfs/compression.c
 create mode 100644 fs/btrfs/ctree.c
 create mode 100644 fs/btrfs/dev.c
 create mode 100644 fs/btrfs/dir-item.c
 create mode 100644 fs/btrfs/extent-io.c
 create mode 100644 fs/btrfs/hash.c
 create mode 100644 fs/btrfs/inode.c
 create mode 100644 fs/btrfs/root.c
 create mode 100644 fs/btrfs/subvolume.c
 create mode 100644 fs/btrfs/super.c
tags/2020-06-01
Marek Behún 3 years ago
committed by Tom Rini
parent
commit
21a14facb1
12 changed files with 1841 additions and 0 deletions
  1. +89
    -0
      fs/btrfs/btrfs.h
  2. +178
    -0
      fs/btrfs/chunk-map.c
  3. +134
    -0
      fs/btrfs/compression.c
  4. +289
    -0
      fs/btrfs/ctree.c
  5. +26
    -0
      fs/btrfs/dev.c
  6. +125
    -0
      fs/btrfs/dir-item.c
  7. +120
    -0
      fs/btrfs/extent-io.c
  8. +38
    -0
      fs/btrfs/hash.c
  9. +385
    -0
      fs/btrfs/inode.c
  10. +93
    -0
      fs/btrfs/root.c
  11. +131
    -0
      fs/btrfs/subvolume.c
  12. +233
    -0
      fs/btrfs/super.c

+ 89
- 0
fs/btrfs/btrfs.h View File

@@ -0,0 +1,89 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#ifndef __BTRFS_BTRFS_H__
#define __BTRFS_BTRFS_H__

#include <linux/rbtree.h>
#include "conv-funcs.h"

struct btrfs_info {
struct btrfs_super_block sb;
struct btrfs_root_backup *root_backup;

struct btrfs_root tree_root;
struct btrfs_root fs_root;
struct btrfs_root chunk_root;

struct rb_root chunks_root;
};

extern struct btrfs_info btrfs_info;

/* hash.c */
void btrfs_hash_init(void);
u32 btrfs_crc32c(u32, const void *, size_t);
u32 btrfs_csum_data(char *, u32, size_t);
void btrfs_csum_final(u32, void *);

static inline u64 btrfs_name_hash(const char *name, int len)
{
return btrfs_crc32c((u32) ~1, name, len);
}

/* dev.c */
extern struct blk_desc *btrfs_blk_desc;
extern disk_partition_t *btrfs_part_info;

int btrfs_devread(u64, int, void *);

/* chunk-map.c */
u64 btrfs_map_logical_to_physical(u64);
int btrfs_chunk_map_init(void);
void btrfs_chunk_map_exit(void);
int btrfs_read_chunk_tree(void);

/* compression.c */
u32 btrfs_decompress(u8 type, const char *, u32, char *, u32);

/* super.c */
int btrfs_read_superblock(void);

/* dir-item.c */
typedef int (*btrfs_readdir_callback_t)(const struct btrfs_root *,
struct btrfs_dir_item *);

int btrfs_lookup_dir_item(const struct btrfs_root *, u64, const char *, int,
struct btrfs_dir_item *);
int btrfs_readdir(const struct btrfs_root *, u64, btrfs_readdir_callback_t);

/* root.c */
int btrfs_find_root(u64, struct btrfs_root *, struct btrfs_root_item *);
u64 btrfs_lookup_root_ref(u64, struct btrfs_root_ref *, char *);

/* inode.c */
u64 btrfs_lookup_inode_ref(struct btrfs_root *, u64, struct btrfs_inode_ref *,
char *);
int btrfs_lookup_inode(const struct btrfs_root *, struct btrfs_key *,
struct btrfs_inode_item *, struct btrfs_root *);
int btrfs_readlink(const struct btrfs_root *, u64, char *);
u64 btrfs_lookup_path(struct btrfs_root *, u64, const char *, u8 *,
struct btrfs_inode_item *, int);
u64 btrfs_file_read(const struct btrfs_root *, u64, u64, u64, char *);

/* subvolume.c */
u64 btrfs_get_default_subvol_objectid(void);

/* extent-io.c */
u64 btrfs_read_extent_inline(struct btrfs_path *,
struct btrfs_file_extent_item *, u64, u64,
char *);
u64 btrfs_read_extent_reg(struct btrfs_path *, struct btrfs_file_extent_item *,
u64, u64, char *);

#endif /* !__BTRFS_BTRFS_H__ */

+ 178
- 0
fs/btrfs/chunk-map.c View File

@@ -0,0 +1,178 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"
#include <malloc.h>

struct chunk_map_item {
struct rb_node node;
u64 logical;
u64 length;
u64 physical;
};

static int add_chunk_mapping(struct btrfs_key *key, struct btrfs_chunk *chunk)
{
struct btrfs_stripe *stripe;
u64 block_profile = chunk->type & BTRFS_BLOCK_GROUP_PROFILE_MASK;
struct rb_node **new = &(btrfs_info.chunks_root.rb_node), *prnt = NULL;
struct chunk_map_item *map_item;

if (block_profile && block_profile != BTRFS_BLOCK_GROUP_DUP) {
printf("%s: unsupported chunk profile %llu\n", __func__,
block_profile);
return -1;
} else if (!chunk->length) {
printf("%s: zero length chunk\n", __func__);
return -1;
}

stripe = &chunk->stripe;
btrfs_stripe_to_cpu(stripe);

while (*new) {
struct chunk_map_item *this;

this = rb_entry(*new, struct chunk_map_item, node);

prnt = *new;
if (key->offset < this->logical) {
new = &((*new)->rb_left);
} else if (key->offset > this->logical) {
new = &((*new)->rb_right);
} else {
debug("%s: Logical address %llu already in map!\n",
__func__, key->offset);
return 0;
}
}

map_item = malloc(sizeof(struct chunk_map_item));
if (!map_item)
return -1;

map_item->logical = key->offset;
map_item->length = chunk->length;
map_item->physical = le64_to_cpu(chunk->stripe.offset);
rb_link_node(&map_item->node, prnt, new);
rb_insert_color(&map_item->node, &btrfs_info.chunks_root);

debug("%s: Mapping %llu to %llu\n", __func__, map_item->logical,
map_item->physical);

return 0;
}

u64 btrfs_map_logical_to_physical(u64 logical)
{
struct rb_node *node = btrfs_info.chunks_root.rb_node;

while (node) {
struct chunk_map_item *item;

item = rb_entry(node, struct chunk_map_item, node);

if (item->logical > logical)
node = node->rb_left;
else if (logical > item->logical + item->length)
node = node->rb_right;
else
return item->physical + logical - item->logical;
}

printf("%s: Cannot map logical address %llu to physical\n", __func__,
logical);

return -1ULL;
}

void btrfs_chunk_map_exit(void)
{
struct rb_node *now, *next;
struct chunk_map_item *item;

for (now = rb_first_postorder(&btrfs_info.chunks_root); now; now = next)
{
item = rb_entry(now, struct chunk_map_item, node);
next = rb_next_postorder(now);
free(item);
}
}

int btrfs_chunk_map_init(void)
{
u8 sys_chunk_array_copy[sizeof(btrfs_info.sb.sys_chunk_array)];
u8 * const start = sys_chunk_array_copy;
u8 * const end = start + btrfs_info.sb.sys_chunk_array_size;
u8 *cur;
struct btrfs_key *key;
struct btrfs_chunk *chunk;

btrfs_info.chunks_root = RB_ROOT;

memcpy(sys_chunk_array_copy, btrfs_info.sb.sys_chunk_array,
sizeof(sys_chunk_array_copy));

for (cur = start; cur < end;) {
key = (struct btrfs_key *) cur;
cur += sizeof(struct btrfs_key);
chunk = (struct btrfs_chunk *) cur;

btrfs_key_to_cpu(key);
btrfs_chunk_to_cpu(chunk);

if (key->type != BTRFS_CHUNK_ITEM_KEY) {
printf("%s: invalid key type %u\n", __func__,
key->type);
return -1;
}

if (add_chunk_mapping(key, chunk))
return -1;

cur += sizeof(struct btrfs_chunk);
cur += sizeof(struct btrfs_stripe) * (chunk->num_stripes - 1);
}

return 0;
}

int btrfs_read_chunk_tree(void)
{
struct btrfs_path path;
struct btrfs_key key, *found_key;
struct btrfs_chunk *chunk;
int res;

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

if (btrfs_search_tree(&btrfs_info.chunk_root, &key, &path))
return -1;

do {
found_key = btrfs_path_leaf_key(&path);
if (btrfs_comp_keys_type(&key, found_key))
break;

chunk = btrfs_path_item_ptr(&path, struct btrfs_chunk);
btrfs_chunk_to_cpu(chunk);
if (add_chunk_mapping(found_key, chunk)) {
res = -1;
break;
}
} while (!(res = btrfs_next_slot(&path)));

btrfs_free_path(&path);

if (res < 0)
return -1;

return 0;
}

+ 134
- 0
fs/btrfs/compression.c View File

@@ -0,0 +1,134 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"
#include <linux/lzo.h>
#include <u-boot/zlib.h>

static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
{
u32 tot_len, in_len, res;
size_t out_len;
int ret;

if (clen < 4)
return -1;

tot_len = le32_to_cpu(*(u32 *) cbuf);
cbuf += 4;
clen -= 4;
tot_len -= 4;

if (tot_len == 0 && dlen)
return -1;
if (tot_len < 4)
return -1;

res = 0;

while (tot_len > 4) {
in_len = le32_to_cpu(*(u32 *) cbuf);
cbuf += 4;
clen -= 4;

if (in_len > clen || tot_len < 4 + in_len)
return -1;

tot_len -= 4 + in_len;

out_len = dlen;
ret = lzo1x_decompress_safe(cbuf, in_len, dbuf, &out_len);
if (ret != LZO_E_OK)
return -1;

cbuf += in_len;
clen -= in_len;
dbuf += out_len;
dlen -= out_len;

res += out_len;
}

return res;
}

/* from zutil.h */
#define PRESET_DICT 0x20

static u32 decompress_zlib(const u8 *_cbuf, u32 clen, u8 *dbuf, u32 dlen)
{
int wbits = MAX_WBITS, ret = -1;
z_stream stream;
u8 *cbuf;
u32 res;

memset(&stream, 0, sizeof(stream));

cbuf = (u8 *) _cbuf;

stream.total_in = 0;

stream.next_out = dbuf;
stream.avail_out = dlen;
stream.total_out = 0;

/* skip adler32 check if deflate and no dictionary */
if (clen > 2 && !(cbuf[1] & PRESET_DICT) &&
((cbuf[0] & 0x0f) == Z_DEFLATED) &&
!(((cbuf[0] << 8) + cbuf[1]) % 31)) {
wbits = -((cbuf[0] >> 4) + 8);
cbuf += 2;
clen -= 2;
}

if (Z_OK != inflateInit2(&stream, wbits))
return -1;

while (stream.total_in < clen) {
stream.next_in = cbuf + stream.total_in;
stream.avail_in = min((u32) (clen - stream.total_in),
(u32) btrfs_info.sb.sectorsize);

ret = inflate(&stream, Z_NO_FLUSH);
if (ret != Z_OK)
break;
}

res = stream.total_out;
inflateEnd(&stream);

if (ret != Z_STREAM_END)
return -1;

return res;
}

u32 btrfs_decompress(u8 type, const char *c, u32 clen, char *d, u32 dlen)
{
u32 res;
const u8 *cbuf;
u8 *dbuf;

cbuf = (const u8 *) c;
dbuf = (u8 *) d;

switch (type) {
case BTRFS_COMPRESS_NONE:
res = dlen < clen ? dlen : clen;
memcpy(dbuf, cbuf, res);
return res;
case BTRFS_COMPRESS_ZLIB:
return decompress_zlib(cbuf, clen, dbuf, dlen);
case BTRFS_COMPRESS_LZO:
return decompress_lzo(cbuf, clen, dbuf, dlen);
default:
printf("%s: Unsupported compression in extent: %i\n", __func__,
type);
return -1;
}
}

+ 289
- 0
fs/btrfs/ctree.c View File

@@ -0,0 +1,289 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"
#include <malloc.h>

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;
}

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;

if (0) {
int i;
printf("\tsearching %llu %i\n", key->objectid, key->type);
for (i = 0; i < max; ++i) {
tmp = (struct btrfs_key *) ((u8 *) addr + i*item_size);
printf("\t\t%llu %i\n", tmp->objectid, tmp->type);
}
printf("\n");
}

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)
{
struct btrfs_header hdr;
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(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;
}

res->header = 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
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] >= leaf->header.nritems)
return jump_leaf(p, 1);

p->slots[0]++;
return 0;
}

+ 26
- 0
fs/btrfs/dev.c View File

@@ -0,0 +1,26 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include <common.h>
#include <compiler.h>
#include <fs_internal.h>

struct blk_desc *btrfs_blk_desc;
disk_partition_t *btrfs_part_info;

int btrfs_devread(u64 address, int byte_len, void *buf)
{
lbaint_t sector;
int byte_offset;

sector = address >> btrfs_blk_desc->log2blksz;
byte_offset = address % btrfs_blk_desc->blksz;

return fs_devread(btrfs_blk_desc, btrfs_part_info, sector, byte_offset,
byte_len, buf);
}

+ 125
- 0
fs/btrfs/dir-item.c View File

@@ -0,0 +1,125 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"

static int verify_dir_item(struct btrfs_dir_item *item, u32 start, u32 total)
{
u16 max_len = BTRFS_NAME_LEN;
u32 end;

if (item->type >= BTRFS_FT_MAX) {
printf("%s: invalid dir item type: %i\n", __func__, item->type);
return 1;
}

if (item->type == BTRFS_FT_XATTR)
max_len = 255; /* XATTR_NAME_MAX */

end = start + sizeof(*item) + item->name_len;
if (item->name_len > max_len || end > total) {
printf("%s: invalid dir item name len: %u\n", __func__,
item->name_len);
return 1;
}

return 0;
}

static struct btrfs_dir_item *
btrfs_match_dir_item_name(struct btrfs_path *path, const char *name,
int name_len)
{
struct btrfs_dir_item *item;
u32 total_len, cur = 0, this_len;
const char *name_ptr;

item = btrfs_path_item_ptr(path, struct btrfs_dir_item);

total_len = btrfs_path_item_size(path);

while (cur < total_len) {
btrfs_dir_item_to_cpu(item);
this_len = sizeof(*item) + item->name_len + item->data_len;
name_ptr = (const char *) (item + 1);

if (verify_dir_item(item, cur, total_len))
return NULL;
if (item->name_len == name_len && !memcmp(name_ptr, name,
name_len))
return item;

cur += this_len;
item = (struct btrfs_dir_item *) ((u8 *) item + this_len);
}

return NULL;
}

int btrfs_lookup_dir_item(const struct btrfs_root *root, u64 dir,
const char *name, int name_len,
struct btrfs_dir_item *item)
{
struct btrfs_path path;
struct btrfs_key key;
struct btrfs_dir_item *res = NULL;

key.objectid = dir;
key.type = BTRFS_DIR_ITEM_KEY;
key.offset = btrfs_name_hash(name, name_len);

if (btrfs_search_tree(root, &key, &path))
return -1;

if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
goto out;

res = btrfs_match_dir_item_name(&path, name, name_len);
if (res)
*item = *res;
out:
btrfs_free_path(&path);
return res ? 0 : -1;
}

int btrfs_readdir(const struct btrfs_root *root, u64 dir,
btrfs_readdir_callback_t callback)
{
struct btrfs_path path;
struct btrfs_key key, *found_key;
struct btrfs_dir_item *item;
int res;

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

if (btrfs_search_tree(root, &key, &path))
return -1;

do {
found_key = btrfs_path_leaf_key(&path);
if (btrfs_comp_keys_type(&key, found_key))
break;

item = btrfs_path_item_ptr(&path, struct btrfs_dir_item);
btrfs_dir_item_to_cpu(item);

if (verify_dir_item(item, 0, sizeof(*item) + item->name_len))
continue;
if (item->type == BTRFS_FT_XATTR)
continue;

if (callback(root, item))
break;
} while (!(res = btrfs_next_slot(&path)));

btrfs_free_path(&path);

return res < 0 ? -1 : 0;
}

+ 120
- 0
fs/btrfs/extent-io.c View File

@@ -0,0 +1,120 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"
#include <malloc.h>

u64 btrfs_read_extent_inline(struct btrfs_path *path,
struct btrfs_file_extent_item *extent, u64 offset,
u64 size, char *out)
{
u32 clen, dlen, orig_size = size, res;
const char *cbuf;
char *dbuf;
const int data_off = offsetof(struct btrfs_file_extent_item,
disk_bytenr);

clen = btrfs_path_item_size(path) - data_off;
cbuf = (const char *) extent + data_off;
dlen = extent->ram_bytes;

if (offset > dlen)
return -1ULL;

if (size > dlen - offset)
size = dlen - offset;

if (extent->compression == BTRFS_COMPRESS_NONE) {
memcpy(out, cbuf + offset, size);
return size;
}

if (dlen > orig_size) {
dbuf = malloc(dlen);
if (!dbuf)
return -1ULL;
} else {
dbuf = out;
}

res = btrfs_decompress(extent->compression, cbuf, clen, dbuf, dlen);
if (res == -1 || res != dlen)
goto err;

if (dlen > orig_size) {
memcpy(out, dbuf + offset, size);
free(dbuf);
} else if (offset) {
memmove(out, dbuf + offset, size);
}

return size;

err:
if (dlen > orig_size)
free(dbuf);
return -1ULL;
}

u64 btrfs_read_extent_reg(struct btrfs_path *path,
struct btrfs_file_extent_item *extent, u64 offset,
u64 size, char *out)
{
u64 physical, clen, dlen, orig_size = size;
u32 res;
char *cbuf, *dbuf;

clen = extent->disk_num_bytes;
dlen = extent->num_bytes;

if (offset > dlen)
return -1ULL;

if (size > dlen - offset)
size = dlen - offset;

physical = btrfs_map_logical_to_physical(extent->disk_bytenr);
if (physical == -1ULL)
return -1ULL;

if (extent->compression == BTRFS_COMPRESS_NONE) {
physical += extent->offset + offset;
if (!btrfs_devread(physical, size, out))
return -1ULL;

return size;
}

cbuf = malloc(dlen > size ? clen + dlen : clen);
if (!cbuf)
return -1ULL;

if (dlen > orig_size)
dbuf = cbuf + clen;
else
dbuf = out;

if (!btrfs_devread(physical, clen, cbuf))
goto err;

res = btrfs_decompress(extent->compression, cbuf, clen, dbuf, dlen);
if (res == -1)
goto err;

if (dlen > orig_size)
memcpy(out, dbuf + offset, size);
else
memmove(out, dbuf + offset, size);

free(cbuf);
return res;

err:
free(cbuf);
return -1ULL;
}

+ 38
- 0
fs/btrfs/hash.c View File

@@ -0,0 +1,38 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"
#include <u-boot/crc.h>

static u32 btrfs_crc32c_table[256];

void btrfs_hash_init(void)
{
static int inited = 0;

if (!inited) {
crc32c_init(btrfs_crc32c_table, 0x82F63B78);
inited = 1;
}
}

u32 btrfs_crc32c(u32 crc, const void *data, size_t length)
{
return crc32c_cal(crc, (const char *) data, length,
btrfs_crc32c_table);
}

u32 btrfs_csum_data(char *data, u32 seed, size_t len)
{
return btrfs_crc32c(seed, data, len);
}

void btrfs_csum_final(u32 crc, void *result)
{
*((u32 *) result) = cpu_to_le32(~crc);
}

+ 385
- 0
fs/btrfs/inode.c View File

@@ -0,0 +1,385 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"
#include <malloc.h>

u64 btrfs_lookup_inode_ref(struct btrfs_root *root, u64 inr,
struct btrfs_inode_ref *refp, char *name)
{
struct btrfs_path path;
struct btrfs_key *key;
struct btrfs_inode_ref *ref;
u64 res = -1ULL;

key = btrfs_search_tree_key_type(root, inr, BTRFS_INODE_REF_KEY,
&path);

if (!key)
return -1ULL;

ref = btrfs_path_item_ptr(&path, struct btrfs_inode_ref);
btrfs_inode_ref_to_cpu(ref);

if (refp)
*refp = *ref;

if (name) {
if (ref->name_len > BTRFS_NAME_MAX) {
printf("%s: inode name too long: %u\n", __func__,
ref->name_len);
goto out;
}

memcpy(name, ref + 1, ref->name_len);
}

res = key->offset;
out:
btrfs_free_path(&path);
return res;
}

int btrfs_lookup_inode(const struct btrfs_root *root,
struct btrfs_key *location,
struct btrfs_inode_item *item,
struct btrfs_root *new_root)
{
struct btrfs_root tmp_root = *root;
struct btrfs_path path;
int res = -1;

if (location->type == BTRFS_ROOT_ITEM_KEY) {
if (btrfs_find_root(location->objectid, &tmp_root, NULL))
return -1;

location->objectid = tmp_root.root_dirid;
location->type = BTRFS_INODE_ITEM_KEY;
location->offset = 0;
}

if (btrfs_search_tree(&tmp_root, location, &path))
return res;

if (btrfs_comp_keys(location, btrfs_path_leaf_key(&path)))
goto out;

if (item) {
*item = *btrfs_path_item_ptr(&path, struct btrfs_inode_item);
btrfs_inode_item_to_cpu(item);
}

if (new_root)
*new_root = tmp_root;

res = 0;

out:
btrfs_free_path(&path);
return res;
}

int btrfs_readlink(const struct btrfs_root *root, u64 inr, char *target)
{
struct btrfs_path path;
struct btrfs_key key;
struct btrfs_file_extent_item *extent;
const char *data_ptr;
int res = -1;

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

if (btrfs_search_tree(root, &key, &path))
return -1;

if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)))
goto out;

extent = btrfs_path_item_ptr(&path, struct btrfs_file_extent_item);
if (extent->type != BTRFS_FILE_EXTENT_INLINE) {
printf("%s: Extent for symlink %llu not of INLINE type\n",
__func__, inr);
goto out;
}

btrfs_file_extent_item_to_cpu_inl(extent);

if (extent->compression != BTRFS_COMPRESS_NONE) {
printf("%s: Symlink %llu extent data compressed!\n", __func__,
inr);
goto out;
} else if (extent->encryption != 0) {
printf("%s: Symlink %llu extent data encrypted!\n", __func__,
inr);
goto out;
} else if (extent->ram_bytes >= btrfs_info.sb.sectorsize) {
printf("%s: Symlink %llu extent data too long (%llu)!\n",
__func__, inr, extent->ram_bytes);
goto out;
}

data_ptr = (const char *) extent
+ offsetof(struct btrfs_file_extent_item, disk_bytenr);

memcpy(target, data_ptr, extent->ram_bytes);
target[extent->ram_bytes] = '\0';
res = 0;
out:
btrfs_free_path(&path);
return res;
}

/* inr must be a directory (for regular files with multiple hard links this
function returns only one of the parents of the file) */
static u64 get_parent_inode(struct btrfs_root *root, u64 inr,
struct btrfs_inode_item *inode_item)
{
struct btrfs_key key;
u64 res;

if (inr == BTRFS_FIRST_FREE_OBJECTID) {
if (root->objectid != btrfs_info.fs_root.objectid) {
u64 parent;
struct btrfs_root_ref ref;

parent = btrfs_lookup_root_ref(root->objectid, &ref,
NULL);
if (parent == -1ULL)
return -1ULL;

if (btrfs_find_root(parent, root, NULL))
return -1ULL;

inr = ref.dirid;
}

if (inode_item) {
key.objectid = inr;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;

if (btrfs_lookup_inode(root, &key, inode_item, NULL))
return -1ULL;
}

return inr;
}

res = btrfs_lookup_inode_ref(root, inr, NULL, NULL);
if (res == -1ULL)
return -1ULL;

if (inode_item) {
key.objectid = res;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;

if (btrfs_lookup_inode(root, &key, inode_item, NULL))
return -1ULL;
}

return res;
}

static inline int next_length(const char *path)
{
int res = 0;
while (*path != '\0' && *path != '/' && res <= BTRFS_NAME_LEN)
++res, ++path;
return res;
}

static inline const char *skip_current_directories(const char *cur)
{
while (1) {
if (cur[0] == '/')
++cur;
else if (cur[0] == '.' && cur[1] == '/')
cur += 2;
else
break;
}

return cur;
}

/* inode.c, musi vratit aj root stromu kde sa inoda najde */
u64 btrfs_lookup_path(struct btrfs_root *root, u64 inr, const char *path,
u8 *type_p, struct btrfs_inode_item *inode_item_p,
int symlink_limit)
{
struct btrfs_dir_item item;
struct btrfs_inode_item inode_item;
u8 type = BTRFS_FT_DIR;
int len, have_inode = 0;
const char *cur = path;

if (*cur == '/') {
++cur;
inr = root->root_dirid;
}

do {
cur = skip_current_directories(cur);

len = next_length(cur);
if (len > BTRFS_NAME_LEN) {
printf("%s: Name too long at \"%.*s\"\n", __func__,
BTRFS_NAME_LEN, cur);
return -1ULL;
}

if (len == 1 && cur[0] == '.')
break;

if (len == 2 && cur[0] == '.' && cur[1] == '.') {
cur += 2;
inr = get_parent_inode(root, inr, &inode_item);
if (inr == -1ULL)
return -1ULL;

type = BTRFS_FT_DIR;
continue;
}

if (!*cur)
break;
if (btrfs_lookup_dir_item(root, inr, cur, len, &item))
return -1ULL;

type = item.type;
have_inode = 1;
if (btrfs_lookup_inode(root, &item.location, &inode_item, root))
return -1ULL;

if (item.type == BTRFS_FT_SYMLINK && symlink_limit >= 0) {
char *target;

if (!symlink_limit) {
printf("%s: Too much symlinks!\n", __func__);
return -1ULL;
}

target = malloc(min(inode_item.size + 1,
(u64) btrfs_info.sb.sectorsize));
if (!target)
return -1ULL;

if (btrfs_readlink(root, item.location.objectid,
target)) {
free(target);
return -1ULL;
}

inr = btrfs_lookup_path(root, inr, target, &type,
&inode_item, symlink_limit - 1);

free(target);

if (inr == -1ULL)
return -1ULL;
} else if (item.type != BTRFS_FT_DIR && cur[len]) {
printf("%s: \"%.*s\" not a directory\n", __func__,
(int) (cur - path + len), path);
return -1ULL;
} else {
inr = item.location.objectid;
}

cur += len;
} while (*cur);

if (type_p)
*type_p = type;

if (inode_item_p) {
if (!have_inode) {
struct btrfs_key key;

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

if (btrfs_lookup_inode(root, &key, &inode_item, NULL))
return -1ULL;
}

*inode_item_p = inode_item;
}

return inr;
}

u64 btrfs_file_read(const struct btrfs_root *root, u64 inr, u64 offset,
u64 size, char *buf)
{
struct btrfs_path path;
struct btrfs_key key;
struct btrfs_file_extent_item *extent;
int res;
u64 rd, rd_all = -1ULL;

key.objectid = inr;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = offset;

if (btrfs_search_tree(root, &key, &path))
return -1ULL;

if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)) < 0) {
if (btrfs_prev_slot(&path))
goto out;

if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
goto out;
}

rd_all = 0;

do {
if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
break;

extent = btrfs_path_item_ptr(&path,
struct btrfs_file_extent_item);

if (extent->type == BTRFS_FILE_EXTENT_INLINE) {
btrfs_file_extent_item_to_cpu_inl(extent);
rd = btrfs_read_extent_inline(&path, extent, offset,
size, buf);
} else {
btrfs_file_extent_item_to_cpu(extent);
rd = btrfs_read_extent_reg(&path, extent, offset, size,
buf);
}

if (rd == -1ULL) {
printf("%s: Error reading extent\n", __func__);
rd_all = -1;
goto out;
}

offset = 0;
buf += rd;
rd_all += rd;
size -= rd;

if (!size)
break;
} while (!(res = btrfs_next_slot(&path)));

if (res)
return -1ULL;

out:
btrfs_free_path(&path);
return rd_all;
}

+ 93
- 0
fs/btrfs/root.c View File

@@ -0,0 +1,93 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"

static void read_root_item(struct btrfs_path *p, struct btrfs_root_item *item)
{
u32 len;
int reset = 0;

len = btrfs_path_item_size(p);
memcpy(item, btrfs_path_item_ptr(p, struct btrfs_root_item), len);
btrfs_root_item_to_cpu(item);

if (len < sizeof(*item))
reset = 1;
if (!reset && item->generation != item->generation_v2) {
if (item->generation_v2 != 0)
printf("%s: generation != generation_v2 in root item",
__func__);
reset = 1;
}
if (reset) {
memset(&item->generation_v2, 0,
sizeof(*item) - offsetof(struct btrfs_root_item,
generation_v2));
}
}

int btrfs_find_root(u64 objectid, struct btrfs_root *root,
struct btrfs_root_item *root_item)
{
struct btrfs_path path;
struct btrfs_root_item my_root_item;

if (!btrfs_search_tree_key_type(&btrfs_info.tree_root, objectid,
BTRFS_ROOT_ITEM_KEY, &path))
return -1;

if (!root_item)
root_item = &my_root_item;
read_root_item(&path, root_item);

if (root) {
root->objectid = objectid;
root->bytenr = root_item->bytenr;
root->root_dirid = root_item->root_dirid;
}

btrfs_free_path(&path);
return 0;
}

u64 btrfs_lookup_root_ref(u64 subvolid, struct btrfs_root_ref *refp, char *name)
{
struct btrfs_path path;
struct btrfs_key *key;
struct btrfs_root_ref *ref;
u64 res = -1ULL;

key = btrfs_search_tree_key_type(&btrfs_info.tree_root, subvolid,
BTRFS_ROOT_BACKREF_KEY, &path);

if (!key)
return -1ULL;

ref = btrfs_path_item_ptr(&path, struct btrfs_root_ref);
btrfs_root_ref_to_cpu(ref);

if (refp)
*refp = *ref;

if (name) {
if (ref->name_len > BTRFS_VOL_NAME_MAX) {
printf("%s: volume name too long: %u\n", __func__,
ref->name_len);
goto out;
}

memcpy(name, ref + 1, ref->name_len);
}

res = key->offset;
out:
btrfs_free_path(&path);
return res;
}


+ 131
- 0
fs/btrfs/subvolume.c View File

@@ -0,0 +1,131 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"
#include <malloc.h>

static int get_subvol_name(u64 subvolid, char *name, int max_len)
{
struct btrfs_root_ref rref;
struct btrfs_inode_ref iref;
struct btrfs_root root;
u64 dir;
char tmp[max(BTRFS_VOL_NAME_MAX, BTRFS_NAME_MAX)];
char *ptr;

ptr = name + max_len - 1;
*ptr = '\0';

while (subvolid != BTRFS_FS_TREE_OBJECTID) {
subvolid = btrfs_lookup_root_ref(subvolid, &rref, tmp);

if (subvolid == -1ULL)
return -1;

ptr -= rref.name_len + 1;
if (ptr < name)
goto too_long;

memcpy(ptr + 1, tmp, rref.name_len);
*ptr = '/';

if (btrfs_find_root(subvolid, &root, NULL))
return -1;

dir = rref.dirid;

while (dir != BTRFS_FIRST_FREE_OBJECTID) {
dir = btrfs_lookup_inode_ref(&root, dir, &iref, tmp);

if (dir == -1ULL)
return -1;

ptr -= iref.name_len + 1;
if (ptr < name)
goto too_long;

memcpy(ptr + 1, tmp, iref.name_len);
*ptr = '/';
}
}

if (ptr == name + max_len - 1) {
name[0] = '/';
name[1] = '\0';
} else {
memmove(name, ptr, name + max_len - ptr);
}

return 0;

too_long:
printf("%s: subvolume name too long\n", __func__);
return -1;
}

u64 btrfs_get_default_subvol_objectid(void)
{
struct btrfs_dir_item item;

if (btrfs_lookup_dir_item(&btrfs_info.tree_root,
btrfs_info.sb.root_dir_objectid, "default", 7,
&item))
return BTRFS_FS_TREE_OBJECTID;
return item.location.objectid;
}

static void list_subvols(u64 tree, char *nameptr, int max_name_len, int level)
{
struct btrfs_key key, *found_key;
struct btrfs_path path;
struct btrfs_root_ref *ref;
int res;

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

if (btrfs_search_tree(&btrfs_info.tree_root, &key, &path))
return;

do {
found_key = btrfs_path_leaf_key(&path);
if (btrfs_comp_keys_type(&key, found_key))
break;

ref = btrfs_path_item_ptr(&path, struct btrfs_root_ref);
btrfs_root_ref_to_cpu(ref);

printf("ID %llu parent %llu name ", found_key->offset, tree);
if (nameptr && !get_subvol_name(found_key->offset, nameptr,
max_name_len))
printf("%s\n", nameptr);
else
printf("%.*s\n", (int) ref->name_len,
(const char *) (ref + 1));

if (level > 0)
list_subvols(found_key->offset, nameptr, max_name_len,
level - 1);
else
printf("%s: Too much recursion, maybe skipping some "
"subvolumes\n", __func__);
} while (!(res = btrfs_next_slot(&path)));

btrfs_free_path(&path);
}

void btrfs_list_subvols(void)
{
char *nameptr = malloc(4096);

list_subvols(BTRFS_FS_TREE_OBJECTID, nameptr, nameptr ? 4096 : 0, 40);

if (nameptr)
free(nameptr);
}

+ 233
- 0
fs/btrfs/super.c View File

@@ -0,0 +1,233 @@
/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/

#include "btrfs.h"

#define BTRFS_SUPER_FLAG_SUPP (BTRFS_HEADER_FLAG_WRITTEN \
| BTRFS_HEADER_FLAG_RELOC \
| BTRFS_SUPER_FLAG_ERROR \
| BTRFS_SUPER_FLAG_SEEDING \
| BTRFS_SUPER_FLAG_METADUMP)

#define BTRFS_SUPER_INFO_SIZE 4096

static int btrfs_newest_root_backup(struct btrfs_super_block *sb)
{
struct btrfs_root_backup *root_backup;
int i, newest = -1;

for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; ++i) {
root_backup = sb->super_roots + i;
if (root_backup->tree_root_gen == sb->generation)
newest = i;
}

return newest;
}

static inline int is_power_of_2(u64 x)
{
return !(x & (x - 1));
}

static int btrfs_check_super_csum(char *raw_disk_sb)
{
struct btrfs_super_block *disk_sb =
(struct btrfs_super_block *) raw_disk_sb;
u16 csum_type = le16_to_cpu(disk_sb->csum_type);

if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
u32 crc = ~(u32) 0;
const int csum_size = sizeof(crc);
char result[csum_size];

crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE, crc,
BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
btrfs_csum_final(crc, result);

if (memcmp(raw_disk_sb, result, csum_size))
return -1;
} else {
return -1;
}

return 0;
}

static int btrfs_check_super(struct btrfs_super_block *sb)
{
int ret = 0;

if (sb->flags & ~BTRFS_SUPER_FLAG_SUPP) {
printf("%s: Unsupported flags: %llu\n", __func__,
sb->flags & ~BTRFS_SUPER_FLAG_SUPP);
}

if (sb->root_level > BTRFS_MAX_LEVEL) {
printf("%s: tree_root level too big: %d >= %d\n", __func__,
sb->root_level, BTRFS_MAX_LEVEL);
ret = -1;
}

if (sb->chunk_root_level > BTRFS_MAX_LEVEL) {
printf("%s: chunk_root level too big: %d >= %d\n", __func__,
sb->chunk_root_level, BTRFS_MAX_LEVEL);
ret = -1;
}

if (sb->log_root_level > BTRFS_MAX_LEVEL) {
printf("%s: log_root level too big: %d >= %d\n", __func__,
sb->log_root_level, BTRFS_MAX_LEVEL);
ret = -1;
}

if (!is_power_of_2(sb->sectorsize) || sb->sectorsize < 4096 ||
sb->sectorsize > BTRFS_MAX_METADATA_BLOCKSIZE) {
printf("%s: invalid sectorsize %u\n", __func__,
sb->sectorsize);
ret = -1;
}

if (!is_power_of_2(sb->nodesize) || sb->nodesize < sb->sectorsize ||
sb->nodesize > BTRFS_MAX_METADATA_BLOCKSIZE) {
printf("%s: invalid nodesize %u\n", __func__, sb->nodesize);
ret = -1;
}

if (sb->nodesize != sb->__unused_leafsize) {
printf("%s: invalid leafsize %u, should be %u\n", __func__,
sb->__unused_leafsize, sb->nodesize);
ret = -1;
}

if (!IS_ALIGNED(sb->root, sb->sectorsize)) {
printf("%s: tree_root block unaligned: %llu\n", __func__,
sb->root);
ret = -1;
}

if (!IS_ALIGNED(sb->chunk_root, sb->sectorsize)) {
printf("%s: chunk_root block unaligned: %llu\n", __func__,
sb->chunk_root);
ret = -1;
}

if (!IS_ALIGNED(sb->log_root, sb->sectorsize)) {
printf("%s: log_root block unaligned: %llu\n", __func__,
sb->log_root);
ret = -1;
}

if (memcmp(sb->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) {
printf("%s: dev_item UUID does not match fsid\n", __func__);
ret = -1;
}

if (sb->bytes_used < 6*sb->nodesize) {
printf("%s: bytes_used is too small %llu\n", __func__,
sb->bytes_used);
ret = -1;
}

if (!is_power_of_2(sb->stripesize)) {
printf("%s: invalid stripesize %u\n", __func__, sb->stripesize);
ret = -1;
}

if (sb->sys_chunk_array_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
printf("%s: system chunk array too big %u > %u\n", __func__,
sb->sys_chunk_array_size, BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
ret = -1;
}

if (sb->sys_chunk_array_size < sizeof(struct btrfs_key) +
sizeof(struct btrfs_chunk)) {
printf("%s: system chunk array too small %u < %u\n", __func__,
sb->sys_chunk_array_size, (u32) sizeof(struct btrfs_key)
+ sizeof(struct btrfs_chunk));
ret = -1;
}

return ret;
}

int btrfs_read_superblock(void)
{
const u64 superblock_offsets[4] = {
0x10000ull,
0x4000000ull,
0x4000000000ull,
0x4000000000000ull
};
char raw_sb[BTRFS_SUPER_INFO_SIZE];
struct btrfs_super_block *sb = (struct btrfs_super_block *) raw_sb;
u64 dev_total_bytes;
int i, root_backup_idx;

dev_total_bytes = (u64) btrfs_part_info->size * btrfs_part_info->blksz;

btrfs_info.sb.generation = 0;

for (i = 0; i < 4; ++i) {
if (superblock_offsets[i] + sizeof(sb) > dev_total_bytes)
break;

if (!btrfs_devread(superblock_offsets[i], BTRFS_SUPER_INFO_SIZE,
raw_sb))
break;

if (btrfs_check_super_csum(raw_sb)) {
printf("%s: invalid checksum at superblock mirror %i\n",
__func__, i);
continue;
}

btrfs_super_block_to_cpu(sb);

if (sb->magic != BTRFS_MAGIC) {
printf("%s: invalid BTRFS magic 0x%016llX at "
"superblock mirror %i\n", __func__, sb->magic,
i);
} else if (sb->bytenr != superblock_offsets[i]) {
printf("%s: invalid bytenr 0x%016llX (expected "
"0x%016llX) at superblock mirror %i\n",
__func__, sb->bytenr, superblock_offsets[i], i);
} else if (btrfs_check_super(sb)) {
printf("%s: Checking superblock mirror %i failed\n",
__func__, i);
} else if (sb->generation > btrfs_info.sb.generation) {
memcpy(&btrfs_info.sb, sb, sizeof(*sb));
} else {
/* Nothing */
}
}

if (!btrfs_info.sb.generation) {
printf("%s: No valid BTRFS superblock found!\n", __func__);
return -1;
}

root_backup_idx = btrfs_newest_root_backup(&btrfs_info.sb);
if (root_backup_idx < 0) {
printf("%s: No valid root_backup found!\n", __func__);
return -1;
}
btrfs_info.root_backup = btrfs_info.sb.super_roots + root_backup_idx;

if (btrfs_info.root_backup->num_devices != 1) {
printf("%s: Unsupported number of devices (%lli). This driver "
"only supports filesystem on one device.\n", __func__,
btrfs_info.root_backup->num_devices);
return -1;
}

debug("Chosen superblock with generation = %llu\n",
btrfs_info.sb.generation);

return 0;
}

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