Commit 20be49e4 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Kevin Wolf
Browse files

cloop: use qemu block API 



Use bdrv_pwrite to access the backing device instead of pread, and
convert the driver to implementing the bdrv_open method which gives
it an already opened BlockDriverState for the underlying device.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent c94304be

block/cloop.c

+12 −14
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 
#include <zlib.h>



typedef struct BDRVCloopState {

    int fd;

    uint32_t block_size;

    uint32_t n_blocks;

    uint64_t* offsets;
@@ -51,23 +50,20 @@ static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename) 
    return 0;

}



static int cloop_open(BlockDriverState *bs, const char *filename, int flags)

static int cloop_open(BlockDriverState *bs, int flags)

{

    BDRVCloopState *s = bs->opaque;

    uint32_t offsets_size,max_compressed_block_size=1,i;



    s->fd = open(filename, O_RDONLY | O_BINARY);

    if (s->fd < 0)

        return -errno;

    bs->read_only = 1;



    /* read header */

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

    if (bdrv_pread(bs->file, 128, &s->block_size, 4) < 4) {

        goto cloop_close;

    }

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



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

    if (bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4) < 4) {

        goto cloop_close;

    }

    s->n_blocks = be32_to_cpu(s->n_blocks);
@@ -75,7 +71,8 @@ static int cloop_open(BlockDriverState *bs, const char *filename, int flags) 
    /* read offsets */

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

    s->offsets = qemu_malloc(offsets_size);

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

    if (bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size) <

            offsets_size) {

	goto cloop_close;

    }

    for(i=0;i<s->n_blocks;i++) {
@@ -99,17 +96,19 @@ static int cloop_open(BlockDriverState *bs, const char *filename, int flags) 
    return 0;



cloop_close:

    close(s->fd);

    return -1;

}



static inline int cloop_read_block(BDRVCloopState *s,int block_num)

static inline int cloop_read_block(BlockDriverState *bs, int block_num)

{

    BDRVCloopState *s = bs->opaque;



    if(s->current_block != block_num) {

	int ret;

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



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

        ret = bdrv_pread(bs->file, s->offsets[block_num], s->compressed_block,

                         bytes);

        if (ret != bytes)

            return -1;
@@ -138,7 +137,7 @@ static int cloop_read(BlockDriverState *bs, int64_t sector_num, 
    for(i=0;i<nb_sectors;i++) {

	uint32_t sector_offset_in_block=((sector_num+i)%s->sectors_per_block),

	    block_num=(sector_num+i)/s->sectors_per_block;

	if(cloop_read_block(s, block_num) != 0)

	if(cloop_read_block(bs, block_num) != 0)

	    return -1;

	memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512);

    }
@@ -148,7 +147,6 @@ static int cloop_read(BlockDriverState *bs, int64_t sector_num, 
static void cloop_close(BlockDriverState *bs)

{

    BDRVCloopState *s = bs->opaque;

    close(s->fd);

    if(s->n_blocks>0)

	free(s->offsets);

    free(s->compressed_block);
@@ -160,7 +158,7 @@ static BlockDriver bdrv_cloop = { 
    .format_name	= "cloop",

    .instance_size	= sizeof(BDRVCloopState),

    .bdrv_probe		= cloop_probe,

    .bdrv_file_open	= cloop_open,

    .bdrv_open		= cloop_open,

    .bdrv_read		= cloop_read,

    .bdrv_close		= cloop_close,

};