Refactor dmg_read_chunk() to start making use of the new DMGReadState
structure and do chunk and sector related calculations based on it.
Add a new argument "DMGReadState *drs" to it.
Signed-off-by: Ashijeet Acharya <ashijeetacha...@gmail.com>
---
block/dmg.c | 153 ++++++++++++++++++++++++++++++++++++------------------------
1 file changed, 91 insertions(+), 62 deletions(-)
diff --git a/block/dmg.c b/block/dmg.c
index 7ae30e3..dc356b0 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -578,78 +578,106 @@ static inline uint32_t search_chunk(BDRVDMGState *s,
uint64_t sector_num)
return s->n_chunks; /* error */
}
-static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num)
+static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num,
+ DMGReadState *drs)
{
BDRVDMGState *s = bs->opaque;
+ int ret;
+ uint32_t sector_offset;
+ uint64_t sectors_read;
+ uint32_t chunk;
+
if (!is_sector_in_chunk(s, s->current_chunk, sector_num)) {
- int ret;
- uint32_t chunk = search_chunk(s, sector_num);
+ chunk = search_chunk(s, sector_num);
+ } else {
+ chunk = drs->saved_chunk_type;
+ }
- if (chunk >= s->n_chunks) {
+ if (chunk >= s->n_chunks) {
+ return -1;
+ }
+
+ /* reset our access point cache if we had a change in current chunk */
+ if (chunk != drs->saved_chunk_type) {
+ cache_access_point(drs, NULL, -1, -1, -1, -1);
+ }
+
+ sector_offset = sector_num - s->sectors[chunk];
+
+ if ((s->sectorcounts[chunk] - sector_offset) > DMG_SECTOR_MAX) {
+ sectors_read = DMG_SECTOR_MAX;
+ } else {
+ sectors_read = s->sectorcounts[chunk] - sector_offset;
+ }
+
+ /* truncate sectors read if it exceeds the 2MB buffer of qemu-img
+ * convert */
+ if ((sector_num % DMG_SECTOR_MAX) + sectors_read > DMG_SECTOR_MAX) {
+ sectors_read = DMG_SECTOR_MAX - (sector_num % DMG_SECTOR_MAX);
+ }
+
+ s->current_chunk = s->n_chunks;
+
+ switch (s->types[chunk]) { /* block entry type */
+ case 0x80000005: { /* zlib compressed */
+ /* we need to buffer, because only the chunk as whole can be
+ * inflated. */
+ ret = bdrv_pread(bs->file, s->offsets[chunk],
+ s->compressed_chunk, s->lengths[chunk]);
+ if (ret != s->lengths[chunk]) {
return -1;
}
- s->current_chunk = s->n_chunks;
- switch (s->types[chunk]) { /* block entry type */
- case 0x80000005: { /* zlib compressed */
- /* we need to buffer, because only the chunk as whole can be
- * inflated. */
- ret = bdrv_pread(bs->file, s->offsets[chunk],
- s->compressed_chunk, s->lengths[chunk]);
- if (ret != s->lengths[chunk]) {
- return -1;
- }
-
- s->zstream.next_in = s->compressed_chunk;
- s->zstream.avail_in = s->lengths[chunk];
- s->zstream.next_out = s->uncompressed_chunk;
- s->zstream.avail_out = 512 * s->sectorcounts[chunk];
- ret = inflateReset(&s->zstream);
- if (ret != Z_OK) {
- return -1;
- }
- ret = inflate(&s->zstream, Z_FINISH);
- if (ret != Z_STREAM_END ||
- s->zstream.total_out != 512 * s->sectorcounts[chunk]) {
- return -1;
- }
- break; }
- case 0x80000006: /* bzip2 compressed */
- if (!dmg_uncompress_bz2) {
- break;
- }
- /* we need to buffer, because only the chunk as whole can be
- * inflated. */
- ret = bdrv_pread(bs->file, s->offsets[chunk],
- s->compressed_chunk, s->lengths[chunk]);
- if (ret != s->lengths[chunk]) {
- return -1;
- }
-
- ret = dmg_uncompress_bz2((char *)s->compressed_chunk,
- (unsigned int) s->lengths[chunk],
- (char *)s->uncompressed_chunk,
- (unsigned int)
- (512 * s->sectorcounts[chunk]));
- if (ret < 0) {
- return ret;
- }
- break;
- case 1: /* copy */
- ret = bdrv_pread(bs->file, s->offsets[chunk],
- s->uncompressed_chunk, s->lengths[chunk]);
- if (ret != s->lengths[chunk]) {
- return -1;
- }
- break;
- case 2: /* zero */
- /* see dmg_read, it is treated specially. No buffer needs to be
- * pre-filled, the zeroes can be set directly. */
+ s->zstream.next_in = s->compressed_chunk;
+ s->zstream.avail_in = s->lengths[chunk];
+ s->zstream.next_out = s->uncompressed_chunk;
+ s->zstream.avail_out = 512 * s->sectorcounts[chunk];
+ ret = inflateReset(&s->zstream);
+ if (ret != Z_OK) {
+ return -1;
+ }
+ ret = inflate(&s->zstream, Z_FINISH);
+ if (ret != Z_STREAM_END ||
+ s->zstream.total_out != 512 * s->sectorcounts[chunk]) {
+ return -1;
+ }
+ break; }
+ case 0x80000006: /* bzip2 compressed */
+ if (!dmg_uncompress_bz2) {
break;
}
- s->current_chunk = chunk;
+ /* we need to buffer, because only the chunk as whole can be
+ * inflated. */
+ ret = bdrv_pread(bs->file, s->offsets[chunk],
+ s->compressed_chunk, s->lengths[chunk]);
+ if (ret != s->lengths[chunk]) {
+ return -1;
+ }
+
+ ret = dmg_uncompress_bz2((char *)s->compressed_chunk,
+ (unsigned int) s->lengths[chunk],
+ (char *)s->uncompressed_chunk,
+ (unsigned int)
+ (512 * s->sectorcounts[chunk]));
+ if (ret < 0) {
+ return ret;
+ }
+ break;
+ case 1: /* copy */
+ ret = bdrv_pread(bs->file, s->offsets[chunk],
+ s->uncompressed_chunk, s->lengths[chunk]);
+ if (ret != s->lengths[chunk]) {
+ return -1;
+ }
+ break;
+ case 2: /* zero */
+ /* see dmg_read, it is treated specially. No buffer needs to be
+ * pre-filled, the zeroes can be set directly. */
+ break;
}
+ s->current_chunk = chunk;
+
return 0;
}
@@ -661,6 +689,7 @@ dmg_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes,
uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
int nb_sectors = bytes >> BDRV_SECTOR_BITS;
int ret, i;
+ DMGReadState *drs = s->drs;
assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
@@ -671,7 +700,7 @@ dmg_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes,
uint32_t sector_offset_in_chunk;
void *data;
- if (dmg_read_chunk(bs, sector_num + i) != 0) {
+ if (dmg_read_chunk(bs, sector_num + i, drs) != 0) {
ret = -EIO;
goto fail;
}
--
2.6.2
