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// SPDX-License-Identifier: GPL-2.0
/*
* 2017 by Marek Behún <kabel@kernel.org>
*
* Derived from code in ext4/dev.c, which was based on reiserfs/dev.c
*/
#define LOG_CATEGORY LOGC_CORE
#include <blk.h>
#include <compiler.h>
#include <log.h>
#include <part.h>
#include <memalign.h>
int fs_devread(struct blk_desc *blk, struct disk_partition *partition,
lbaint_t sector, int byte_offset, int byte_len, char *buf)
{
unsigned block_len;
int log2blksz;
ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
if (blk == NULL) {
log_err("** Invalid Block Device Descriptor (NULL)\n");
return 0;
}
log2blksz = blk->log2blksz;
/* Check partition boundaries */
if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
>= partition->size) {
log_debug("read outside partition " LBAFU "\n", sector);
return 0;
}
/* Get the read to the beginning of a partition */
sector += byte_offset >> log2blksz;
byte_offset &= blk->blksz - 1;
log_debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
if (byte_offset != 0) {
int readlen;
/* read first part which isn't aligned with start of sector */
if (blk_dread(blk, partition->start + sector, 1,
(void *)sec_buf) != 1) {
log_err(" ** %s read error **\n", __func__);
return 0;
}
readlen = min((int)blk->blksz - byte_offset,
byte_len);
memcpy(buf, sec_buf + byte_offset, readlen);
buf += readlen;
byte_len -= readlen;
sector++;
}
if (byte_len == 0)
return 1;
/* read sector aligned part */
block_len = byte_len & ~(blk->blksz - 1);
if (block_len == 0) {
ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz);
block_len = blk->blksz;
blk_dread(blk, partition->start + sector, 1,
(void *)p);
memcpy(buf, p, byte_len);
return 1;
}
if (blk_dread(blk, partition->start + sector,
block_len >> log2blksz, (void *)buf) !=
block_len >> log2blksz) {
log_err(" ** %s read error - block\n", __func__);
return 0;
}
block_len = byte_len & ~(blk->blksz - 1);
buf += block_len;
byte_len -= block_len;
sector += block_len / blk->blksz;
if (byte_len != 0) {
/* read rest of data which are not in whole sector */
if (blk_dread(blk, partition->start + sector, 1,
(void *)sec_buf) != 1) {
log_err("* %s read error - last part\n", __func__);
return 0;
}
memcpy(buf, sec_buf, byte_len);
}
return 1;
}
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