Add dirty bitmap extension as specified in docs/specs/qcow2.txt. For now, just mirror extension header into Qcow2 state and check constraints.
For now, disable image resize if it has bitmaps. It will be fixed later. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> --- block/qcow2.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ block/qcow2.h | 4 +++ 2 files changed, 87 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index c079aa8..08c4ef9 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -63,6 +63,7 @@ typedef struct { #define QCOW2_EXT_MAGIC_END 0 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 +#define QCOW2_EXT_MAGIC_DIRTY_BITMAPS 0x23852875 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) { @@ -92,6 +93,7 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, QCowExtension ext; uint64_t offset; int ret; + Qcow2BitmapHeaderExt bitmaps_ext; #ifdef DEBUG_EXT printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); @@ -162,6 +164,62 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, } break; + case QCOW2_EXT_MAGIC_DIRTY_BITMAPS: + ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); + if (ret < 0) { + error_setg_errno(errp, -ret, "ERROR: bitmaps_ext: " + "Could not read ext header"); + return ret; + } + + if (bitmaps_ext.reserved32 != 0) { + error_setg_errno(errp, -ret, "ERROR: bitmaps_ext: " + "Reserved field is not zero."); + return -EINVAL; + } + + be32_to_cpus(&bitmaps_ext.nb_bitmaps); + be64_to_cpus(&bitmaps_ext.bitmap_directory_size); + be64_to_cpus(&bitmaps_ext.bitmap_directory_offset); + + if (bitmaps_ext.nb_bitmaps > QCOW_MAX_DIRTY_BITMAPS) { + error_setg(errp, "ERROR: bitmaps_ext: " + "too many dirty bitmaps"); + return -EINVAL; + } + + if (bitmaps_ext.nb_bitmaps == 0) { + error_setg(errp, "ERROR: bitmaps_ext: " + "found bitmaps extension with zero bitmaps"); + return -EINVAL; + } + + if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) { + error_setg(errp, "ERROR: bitmaps_ext: " + "wrong dirty bitmap directory offset"); + return -EINVAL; + } + + if (bitmaps_ext.bitmap_directory_size > + QCOW_MAX_DIRTY_BITMAP_DIRECTORY_SIZE) { + error_setg(errp, "ERROR: bitmaps_ext: " + "too large dirty bitmap directory"); + return -EINVAL; + } + + s->nb_bitmaps = bitmaps_ext.nb_bitmaps; + s->bitmap_directory_offset = + bitmaps_ext.bitmap_directory_offset; + s->bitmap_directory_size = + bitmaps_ext.bitmap_directory_size; + +#ifdef DEBUG_EXT + printf("Qcow2: Got dirty bitmaps extension:" + " offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", + s->bitmap_directory_offset, s->nb_bitmaps); +#endif + break; + default: /* unknown magic - save it in case we need to rewrite the header */ { @@ -1939,6 +1997,24 @@ int qcow2_update_header(BlockDriverState *bs) buflen -= ret; } + if (s->nb_bitmaps > 0) { + Qcow2BitmapHeaderExt bitmaps_header = { + .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), + .bitmap_directory_size = + cpu_to_be64(s->bitmap_directory_size), + .bitmap_directory_offset = + cpu_to_be64(s->bitmap_directory_offset) + }; + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DIRTY_BITMAPS, + &bitmaps_header, sizeof(bitmaps_header), + buflen); + if (ret < 0) { + goto fail; + } + buf += ret; + buflen -= ret; + } + /* Keep unknown header extensions */ QLIST_FOREACH(uext, &s->unknown_header_ext, next) { ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); @@ -2509,6 +2585,13 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset) return -ENOTSUP; } + /* cannot proceed if image has bitmaps */ + if (s->nb_bitmaps) { + /* FIXME */ + error_report("Can't resize an image which has bitmaps"); + return -ENOTSUP; + } + /* shrinking is currently not supported */ if (offset < bs->total_sectors * 512) { error_report("qcow2 doesn't support shrinking images yet"); diff --git a/block/qcow2.h b/block/qcow2.h index 0480b8b..c068b2c 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -292,6 +292,10 @@ typedef struct BDRVQcow2State { unsigned int nb_snapshots; QCowSnapshot *snapshots; + uint64_t bitmap_directory_offset; + uint64_t bitmap_directory_size; + uint32_t nb_bitmaps; + int flags; int qcow_version; bool use_lazy_refcounts; -- 1.8.3.1