blob: 0fa69ab395113f69cf26abe965f2bd3752b45bf6 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
/*
* Created by Li Guifu <blucerlee@gmail.com>
*/
#include <string.h>
#include <stdlib.h>
#include "erofs/io.h"
#include "erofs/print.h"
static bool check_layout_compatibility(struct erofs_sb_info *sbi,
struct erofs_super_block *dsb)
{
const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
sbi->feature_incompat = feature;
/* check if current kernel meets all mandatory requirements */
if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
erofs_err("unidentified incompatible feature %x, please upgrade kernel version",
feature & ~EROFS_ALL_FEATURE_INCOMPAT);
return false;
}
return true;
}
int erofs_read_superblock(void)
{
char data[EROFS_BLKSIZ];
struct erofs_super_block *dsb;
unsigned int blkszbits;
int ret;
ret = blk_read(data, 0, 1);
if (ret < 0) {
erofs_err("cannot read erofs superblock: %d", ret);
return -EIO;
}
dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
ret = -EINVAL;
if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
erofs_err("cannot find valid erofs superblock");
return ret;
}
sbi.feature_compat = le32_to_cpu(dsb->feature_compat);
blkszbits = dsb->blkszbits;
/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
if (blkszbits != LOG_BLOCK_SIZE) {
erofs_err("blksize %u isn't supported on this platform",
1 << blkszbits);
return ret;
}
if (!check_layout_compatibility(&sbi, dsb))
return ret;
sbi.blocks = le32_to_cpu(dsb->blocks);
sbi.meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
sbi.xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
sbi.islotbits = EROFS_ISLOTBITS;
sbi.root_nid = le16_to_cpu(dsb->root_nid);
sbi.inos = le64_to_cpu(dsb->inos);
sbi.build_time = le64_to_cpu(dsb->build_time);
sbi.build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
memcpy(&sbi.uuid, dsb->uuid, sizeof(dsb->uuid));
return 0;
}