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fs/fs_internal.c 2.29 KB
d41ce506b   Eric Lee   Initial Release, ...
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  /*
   * 2017 by Marek Behun <marek.behun@nic.cz>
   *
   * Derived from code in ext4/dev.c, which was based on reiserfs/dev.c
   *
   * SPDX-License-Identifier:	GPL-2.0
   */
  
  #include <common.h>
  #include <compiler.h>
  #include <part.h>
  #include <memalign.h>
  
  int fs_devread(struct blk_desc *blk, disk_partition_t *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) {
  		printf("** Invalid Block Device Descriptor (NULL)
  ");
  		return 0;
  	}
  	log2blksz = blk->log2blksz;
  
  	/* Check partition boundaries */
  	if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
  	    >= partition->size) {
  		printf("%s read outside partition " LBAFU "
  ", __func__,
  		       sector);
  		return 0;
  	}
  
  	/* Get the read to the beginning of a partition */
  	sector += byte_offset >> log2blksz;
  	byte_offset &= blk->blksz - 1;
  
  	debug(" <" LBAFU ", %d, %d>
  ", 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) {
  			printf(" ** %s read error **
  ", __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) {
  		printf(" ** %s read error - block
  ", __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) {
  			printf("* %s read error - last part
  ", __func__);
  			return 0;
  		}
  		memcpy(buf, sec_buf, byte_len);
  	}
  	return 1;
  }