Commit c94304be authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Kevin Wolf
Browse files

cloop: use pread 



Use pread instead of lseek + read in preparation of using the qemu
block API.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent cb7cf0e3

block/cloop.c

+17 −15
Original line number Diff line number Diff line
@@ -62,23 +62,22 @@ static int cloop_open(BlockDriverState *bs, const char *filename, int flags) 
    bs->read_only = 1;



    /* read header */

    if(lseek(s->fd,128,SEEK_SET)<0) {

cloop_close:

	close(s->fd);

	return -1;

    }

    if(read(s->fd,&s->block_size,4)<4)

    if (pread(s->fd, &s->block_size, 4, 128) < 4) {

        goto cloop_close;

    }

    s->block_size = be32_to_cpu(s->block_size);

    if(read(s->fd,&s->n_blocks,4)<4)



    if (pread(s->fd, &s->n_blocks, 4, 128 + 4) < 4) {

        goto cloop_close;

    }

    s->n_blocks = be32_to_cpu(s->n_blocks);



    /* read offsets */

    offsets_size = s->n_blocks * sizeof(uint64_t);

    s->offsets=(uint64_t*)qemu_malloc(offsets_size);

    if(read(s->fd,s->offsets,offsets_size)<offsets_size)

    s->offsets = qemu_malloc(offsets_size);

    if (pread(s->fd, s->offsets, offsets_size, 128 + 4 + 4) < offsets_size) {

	goto cloop_close;

    }

    for(i=0;i<s->n_blocks;i++) {

	s->offsets[i]=be64_to_cpu(s->offsets[i]);

	if(i>0) {
@@ -98,6 +97,10 @@ cloop_close: 
    s->sectors_per_block = s->block_size/512;

    bs->total_sectors = s->n_blocks*s->sectors_per_block;

    return 0;



cloop_close:

    close(s->fd);

    return -1;

}



static inline int cloop_read_block(BDRVCloopState *s,int block_num)
@@ -106,8 +109,7 @@ static inline int cloop_read_block(BDRVCloopState *s,int block_num) 
	int ret;

        uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num];



	lseek(s->fd, s->offsets[block_num], SEEK_SET);

        ret = read(s->fd, s->compressed_block, bytes);

        ret = pread(s->fd, s->compressed_block, bytes, s->offsets[block_num]);

        if (ret != bytes)

            return -1;