On 30.09.2016 12:53, Vladimir Sementsov-Ogievskiy wrote: > Realize block bitmap stroing interface, to allow qcow2 images store > persistent bitmaps. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/qcow2-bitmap.c | 241 +++++++++++++++++++++++++++++++++++++++++++++++++++ > block/qcow2.c | 2 + > block/qcow2.h | 2 + > 3 files changed, 245 insertions(+) > > diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c > index 81520cd..a5be25a 100644 > --- a/block/qcow2-bitmap.c > +++ b/block/qcow2-bitmap.c > @@ -27,6 +27,7 @@ > > #include "qemu/osdep.h" > #include "qapi/error.h" > +#include "qemu/cutils.h" > > #include "block/block_int.h" > #include "block/qcow2.h" > @@ -96,6 +97,15 @@ static inline void bitmap_table_to_cpu(uint64_t *bitmap_table, size_t size) > } > } > > +static inline void bitmap_table_to_be(uint64_t *bitmap_table, size_t size) > +{ > + size_t i; > + > + for (i = 0; i < size; ++i) { > + cpu_to_be64s(&bitmap_table[i]); > + } > +} > + > static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size) > { > return align_offset(sizeof(Qcow2BitmapDirEntry) + > @@ -564,3 +574,234 @@ out: > > return ret; > } > + > +/* store_bitmap_data() > + * Store bitmap to image, filling bitamp table accordingly. > + */ > +static int store_bitmap_data(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, > + uint64_t *bitmap_table, uint32_t bitmap_table_size) > +{ > + int ret; > + BDRVQcow2State *s = bs->opaque; > + uint64_t sector, dsc; > + uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap); > + int cl_size = s->cluster_size; > + uint8_t *buf = NULL; > + uint32_t tb_size = > + size_to_clusters(s, > + bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size)); > + > + BdrvDirtyBitmapIter *dbi; > + > + if (tb_size != bitmap_table_size) { > + return -EINVAL; > + } > + > + memset(bitmap_table, 0, bitmap_table_size * sizeof(bitmap_table[0])); > + > + dbi = bdrv_dirty_iter_new(bitmap, 0); > + buf = g_malloc(cl_size); > + dsc = dirty_sectors_in_cluster(s, bitmap); > + > + while ((sector = bdrv_dirty_iter_next(dbi)) != -1) { > + uint64_t cluster = sector / dsc; > + sector = cluster * dsc; > + uint64_t end = MIN(bm_size, sector + dsc); > + uint64_t write_size = > + bdrv_dirty_bitmap_serialization_size(bitmap, sector, end - sector); > + > + int64_t off = qcow2_alloc_clusters(bs, cl_size); > + if (off < 0) { > + ret = off; > + goto finish; > + } > + bitmap_table[cluster] = off; > + > + bdrv_dirty_bitmap_serialize_part(bitmap, buf, sector, end); > + if (write_size < cl_size) { > + memset(buf + write_size, 0, cl_size - write_size); > + } > + > + ret = bdrv_pwrite(bs->file, off, buf, cl_size); > + if (ret < 0) { > + goto finish; > + } > + > + if (end >= bm_size) { > + break; > + } > + > + bdrv_set_dirty_iter(dbi, end); > + } > + ret = 0; /* writes */ What is that comment supposed to mean? > + > +finish: > + if (ret < 0) { > + clear_bitmap_table(bs, bitmap_table, bitmap_table_size); > + } > + g_free(buf); > + bdrv_dirty_iter_free(dbi); > + > + return ret; In case you decide to keep BME_MAX_PHYS_SIZE, this function should check somewhere that the physical size of the bitmap does not exceed that value. > +} > + > +/* store_bitmap() > + * Store bitmap to qcow2 and set bitmap_table. bitmap_table itself is not > + * stored to qcow2. First of all, there is no parameter called "bitmap_table", and second, yes, the bitmap table is written to the qcow2 file. > + */ > +static int store_bitmap(BlockDriverState *bs, > + BdrvDirtyBitmap *bitmap, > + Qcow2BitmapDirEntry *entry) > +{ > + int ret; > + BDRVQcow2State *s = bs->opaque; > + uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap); > + const char *bm_name = bdrv_dirty_bitmap_name(bitmap); > + > + uint64_t *tb; > + int64_t tb_offset; > + uint32_t tb_size = > + size_to_clusters(s, > + bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size)); As above, this variable should be of type uint64_t. Also, you have to check that it does not exceed BME_MAX_TABLE_SIZE. > + > + tb = g_try_new(uint64_t, tb_size); > + if (tb == NULL) { > + return -ENOMEM; > + } > + > + ret = store_bitmap_data(bs, bitmap, tb, tb_size); > + if (ret < 0) { > + g_free(tb); > + return ret; > + } > + > + tb_offset = qcow2_alloc_clusters(bs, tb_size * sizeof(tb[0])); If you don't limit tb_size, then this multiplication can overflow on 32 bit machines. > + if (tb_offset < 0) { > + ret = tb_offset; > + goto fail; > + } > + There should be a metadata overlap check here. > + bitmap_table_to_be(tb, tb_size); > + ret = bdrv_pwrite(bs->file, tb_offset, tb, tb_size * sizeof(tb[0])); > + if (ret < 0) { > + goto fail; > + } > + > + g_free(tb); > + > + entry->bitmap_table_offset = tb_offset; > + entry->bitmap_table_size = tb_size; > + entry->flags = bdrv_dirty_bitmap_granularity(bitmap) ? BME_FLAG_AUTO : 0; s/granularity/get_autoload/ > + entry->type = BT_DIRTY_TRACKING_BITMAP; > + entry->granularity_bits = ctz32(bdrv_dirty_bitmap_granularity(bitmap)); You should probably check somewhere that the resulting value for entry->granularity_bits is in the BME_{MIN,MAX}_GRANULARITY_BITS range. > + entry->name_size = strlen(bm_name); And that this length does not exceed BME_MAX_NAME_SIZE. > + entry->extra_data_size = 0; > + memcpy(entry + 1, bm_name, entry->name_size); > + > + return 0; > + > +fail: > + clear_bitmap_table(bs, tb, tb_size); > + > + if (tb_offset > 0) { > + qcow2_free_clusters(bs, tb_offset, tb_size, QCOW2_DISCARD_ALWAYS); As before, I'd vote for QCOW2_DISCARD_OTHER. > + } > + > + g_free(tb); > + > + return ret; > +} > + > +static Qcow2BitmapDirEntry *find_bitmap_by_name(uint8_t *bitmap_directory, > + size_t size, const char *name) > +{ > + Qcow2BitmapDirEntry *e; > + > + for_each_bitmap_dir_entry(e, bitmap_directory, size) { > + if (strncmp((char *)(e + 1), name, e->name_size) == 0) { > + return e; > + } > + } > + > + return NULL; > +} > + > +void qcow2_store_persistent_bitmaps(BlockDriverState *bs, Error **errp) > +{ > + BdrvDirtyBitmap *bm; > + BDRVQcow2State *s = bs->opaque; > + uint32_t new_nb_bitmaps = s->nb_bitmaps; > + uint64_t new_dir_size = s->bitmap_directory_size; > + uint8_t *dir = NULL, *new_dir = NULL; > + int ret; > + Qcow2BitmapDirEntry *new_pos; > + > + if (s->nb_bitmaps > 0) { > + dir = directory_read(bs, s->bitmap_directory_offset, > + s->bitmap_directory_size, errp); > + if (dir == NULL) { > + goto out; > + } > + } > + > + for (bm = bdrv_dirty_bitmap_next(bs, NULL); bm != NULL; > + bm = bdrv_dirty_bitmap_next(bs, bm)) { > + const char *name = bdrv_dirty_bitmap_name(bm); > + > + if (!bdrv_dirty_bitmap_get_persistance(bm)) { > + continue; > + } > + > + if (s->nb_bitmaps > 0 && > + find_bitmap_by_name(dir, s->bitmap_directory_size, name)) { > + error_setg(errp, > + "Can't store bitmap '%s' to '%s', as it already exists", > + name, bdrv_get_device_or_node_name(bs)); > + goto out; > + } > + > + new_nb_bitmaps++; > + new_dir_size += calc_dir_entry_size(strlen(name), 0); > + } > + > + if (s->nb_bitmaps == new_nb_bitmaps) { > + /* No new bitmaps - nothing to do */ > + goto out; > + } > + > + new_dir = g_try_malloc0(new_dir_size); > + if (new_dir == NULL) { > + error_setg(errp, "Can't allocate space for bitmap directory."); > + goto out; > + } > + > + memcpy(new_dir, dir, s->bitmap_directory_size); > + new_pos = (Qcow2BitmapDirEntry *)(new_dir + s->bitmap_directory_size); > + > + for (bm = bdrv_dirty_bitmap_next(bs, NULL); bm != NULL; > + bm = bdrv_dirty_bitmap_next(bs, bm)) { > + if (!bdrv_dirty_bitmap_get_persistance(bm)) { > + continue; > + } > + > + ret = store_bitmap(bs, bm, new_pos); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Can't store bitmap '%s' to '%s'", > + bdrv_dirty_bitmap_name(bm), > + bdrv_get_device_or_node_name(bs)); > + goto out; > + } > + new_pos = next_dir_entry(new_pos); > + } > + > + ret = directory_update(bs, new_dir, new_dir_size, new_nb_bitmaps); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Can't update bitmap directory in '%s'", > + bdrv_get_device_or_node_name(bs)); > + goto out; > + } > + > +out: > + g_free(new_dir); > + g_free(dir); This error path leaks all the bitmaps that have been written successfully (if any). I guess this is more or less fine if directory_update() failed (because you can't really tell the state of the image header after directory_update(), so better be safe) but it's not so fine if just some store_bitmap() failed. Max > +} > diff --git a/block/qcow2.c b/block/qcow2.c > index 02ec224..8238205 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -3493,6 +3493,8 @@ BlockDriver bdrv_qcow2 = { > > .bdrv_detach_aio_context = qcow2_detach_aio_context, > .bdrv_attach_aio_context = qcow2_attach_aio_context, > + > + .bdrv_store_persistent_bitmaps = qcow2_store_persistent_bitmaps, > }; > > static void bdrv_qcow2_init(void) > diff --git a/block/qcow2.h b/block/qcow2.h > index 482a29f..dfcf4c6 100644 > --- a/block/qcow2.h > +++ b/block/qcow2.h > @@ -627,4 +627,6 @@ int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, > void **table); > void qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); > > +void qcow2_store_persistent_bitmaps(BlockDriverState *bs, Error **errp); > + > #endif >