Realize block bitmap storing interface, to allow qcow2 images store persistent bitmaps.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> --- block/qcow2-bitmap.c | 509 +++++++++++++++++++++++++++++++++++++++++++++++++-- block/qcow2.c | 1 + block/qcow2.h | 1 + 3 files changed, 496 insertions(+), 15 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index 3e8fd030d9..a2b857ea72 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -28,6 +28,7 @@ #include "qemu/osdep.h" #include "qapi/error.h" #include "exec/log.h" +#include "qemu/cutils.h" #include "block/block_int.h" #include "block/qcow2.h" @@ -43,6 +44,10 @@ #define BME_MIN_GRANULARITY_BITS 9 #define BME_MAX_NAME_SIZE 1023 +#if BME_MAX_TABLE_SIZE * 8ULL > INT_MAX +#error In the code bitmap table physical size assumed to fit into int +#endif + /* Bitmap directory entry flags */ #define BME_RESERVED_FLAGS 0xfffffffcU #define BME_FLAG_IN_USE 1 @@ -67,13 +72,21 @@ typedef struct QEMU_PACKED Qcow2BitmapDirEntry { /* name follows */ } Qcow2BitmapDirEntry; +typedef struct Qcow2BitmapTable { + uint64_t offset; + uint32_t size; /* number of 64bit entries */ + QSIMPLEQ_ENTRY(Qcow2BitmapTable) entry; +} Qcow2BitmapTable; +typedef QSIMPLEQ_HEAD(Qcow2BitmapTableList, Qcow2BitmapTable) Qcow2BitmapTableList; + typedef struct Qcow2Bitmap { - uint64_t table_offset; - uint32_t table_size; + Qcow2BitmapTable table; uint32_t flags; uint8_t granularity_bits; char *name; + BdrvDirtyBitmap *dirty_bitmap; + QSIMPLEQ_ENTRY(Qcow2Bitmap) entry; } Qcow2Bitmap; typedef QSIMPLEQ_HEAD(Qcow2BitmapList, Qcow2Bitmap) Qcow2BitmapList; @@ -87,6 +100,27 @@ static inline bool can_write(BlockDriverState *bs) return !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE); } +static int update_header_sync(BlockDriverState *bs) +{ + int ret; + + ret = qcow2_update_header(bs); + if (ret < 0) { + return ret; + } + + /* We don't return bdrv_flush error code. Even if it fails, write was + * successful and it is more logical to consider that header is in the new + * state than in the old. + */ + ret = bdrv_flush(bs); + if (ret < 0) { + fprintf(stderr, "Failed to flush qcow2 header"); + } + + return 0; +} + static inline void bitmap_table_to_cpu(uint64_t *bitmap_table, size_t size) { size_t i; @@ -96,6 +130,15 @@ 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 int check_table_entry(uint64_t entry, int cluster_size) { uint64_t offset; @@ -123,7 +166,50 @@ static int check_table_entry(uint64_t entry, int cluster_size) return 0; } -static int bitmap_table_load(BlockDriverState *bs, Qcow2Bitmap *bm, +static int check_constraints_on_bitmap(BlockDriverState *bs, + const char *name, + uint32_t granularity) +{ + BDRVQcow2State *s = bs->opaque; + int granularity_bits = ctz32(granularity); + int64_t len = bdrv_getlength(bs); + bool fail; + + assert(granularity > 0); + assert((granularity & (granularity - 1)) == 0); + + if (len < 0) { + return len; + } + + fail = (granularity_bits > BME_MAX_GRANULARITY_BITS) || + (granularity_bits < BME_MIN_GRANULARITY_BITS) || + (len > (uint64_t)BME_MAX_PHYS_SIZE << granularity_bits) || + (len > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size << + granularity_bits) || + (strlen(name) > BME_MAX_NAME_SIZE); + + return fail ? -EINVAL : 0; +} + +static void clear_bitmap_table(BlockDriverState *bs, uint64_t *bitmap_table, + uint32_t bitmap_table_size) +{ + BDRVQcow2State *s = bs->opaque; + int i; + + for (i = 0; i < bitmap_table_size; ++i) { + uint64_t addr = bitmap_table[i] & BME_TABLE_ENTRY_OFFSET_MASK; + if (!addr) { + continue; + } + + qcow2_free_clusters(bs, addr, s->cluster_size, QCOW2_DISCARD_OTHER); + bitmap_table[i] = 0; + } +} + +static int bitmap_table_load(BlockDriverState *bs, Qcow2BitmapTable *tb, uint64_t **bitmap_table) { int ret; @@ -131,20 +217,20 @@ static int bitmap_table_load(BlockDriverState *bs, Qcow2Bitmap *bm, uint32_t i; uint64_t *table; - assert(bm->table_size != 0); - table = g_try_new(uint64_t, bm->table_size); + assert(tb->size != 0); + table = g_try_new(uint64_t, tb->size); if (table == NULL) { return -ENOMEM; } - assert(bm->table_size <= BME_MAX_TABLE_SIZE); - ret = bdrv_pread(bs->file, bm->table_offset, - table, bm->table_size * sizeof(uint64_t)); + assert(tb->size <= BME_MAX_TABLE_SIZE); + ret = bdrv_pread(bs->file, tb->offset, + table, tb->size * sizeof(uint64_t)); if (ret < 0) { goto fail; } - for (i = 0; i < bm->table_size; ++i) { + for (i = 0; i < tb->size; ++i) { be64_to_cpus(&table[i]); ret = check_table_entry(table[i], s->cluster_size); if (ret < 0) { @@ -161,6 +247,28 @@ fail: return ret; } +static int free_bitmap_clusters(BlockDriverState *bs, Qcow2BitmapTable *tb) +{ + int ret; + uint64_t *bitmap_table; + + ret = bitmap_table_load(bs, tb, &bitmap_table); + if (ret < 0) { + assert(bitmap_table == NULL); + return ret; + } + + clear_bitmap_table(bs, bitmap_table, tb->size); + qcow2_free_clusters(bs, tb->offset, tb->size * sizeof(uint64_t), + QCOW2_DISCARD_OTHER); + g_free(bitmap_table); + + tb->offset = 0; + tb->size = 0; + + return 0; +} + /* This function returns the number of disk sectors covered by a single cluster * of bitmap data. */ static uint64_t disk_sectors_in_bitmap_cluster(const BDRVQcow2State *s, @@ -242,7 +350,7 @@ static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs, goto fail; } - ret = bitmap_table_load(bs, bm, &bitmap_table); + ret = bitmap_table_load(bs, &bm->table, &bitmap_table); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read bitmap_table table from image for " @@ -256,7 +364,7 @@ static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs, goto fail; } - ret = load_bitmap_data(bs, bitmap_table, bm->table_size, + ret = load_bitmap_data(bs, bitmap_table, bm->table.size, bitmap); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read bitmap '%s' from image", @@ -492,8 +600,8 @@ static Qcow2BitmapList *bitmap_list_load(BlockDriverState *bs, uint64_t offset, } bm = g_new(Qcow2Bitmap, 1); - bm->table_offset = e->bitmap_table_offset; - bm->table_size = e->bitmap_table_size; + bm->table.offset = e->bitmap_table_offset; + bm->table.size = e->bitmap_table_size; bm->flags = e->flags; bm->granularity_bits = e->granularity_bits; bm->name = dir_entry_copy_name(e); @@ -561,8 +669,8 @@ static int bitmap_list_store(BlockDriverState *bs, Qcow2BitmapList *bm_list, e = (Qcow2BitmapDirEntry *)dir; QSIMPLEQ_FOREACH(bm, bm_list, entry) { - e->bitmap_table_offset = bm->table_offset; - e->bitmap_table_size = bm->table_size; + e->bitmap_table_offset = bm->table.offset; + e->bitmap_table_size = bm->table.size; e->flags = bm->flags; e->type = BT_DIRTY_TRACKING_BITMAP; e->granularity_bits = bm->granularity_bits; @@ -654,6 +762,69 @@ static int update_ext_header_and_dir_in_place(BlockDriverState *bs, return update_header_sync(bs); } +static int update_ext_header_and_dir(BlockDriverState *bs, + Qcow2BitmapList *bm_list) +{ + BDRVQcow2State *s = bs->opaque; + int ret; + uint64_t new_offset = 0; + uint64_t new_size = 0; + uint32_t new_nb_bitmaps = 0; + uint64_t old_offset = s->bitmap_directory_offset; + uint64_t old_size = s->bitmap_directory_size; + uint32_t old_nb_bitmaps = s->nb_bitmaps; + uint64_t old_autocl = s->autoclear_features; + + if (bm_list != NULL && !QSIMPLEQ_EMPTY(bm_list)) { + new_nb_bitmaps = bitmap_list_count(bm_list); + + if (new_nb_bitmaps > QCOW2_MAX_BITMAPS) { + return -EINVAL; + } + + ret = bitmap_list_store(bs, bm_list, &new_offset, &new_size, false); + if (ret < 0) { + return ret; + } + + ret = bdrv_flush(bs->file->bs); + if (ret < 0) { + goto fail; + } + + s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS; + } else { + s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS; + } + + s->bitmap_directory_offset = new_offset; + s->bitmap_directory_size = new_size; + s->nb_bitmaps = new_nb_bitmaps; + + ret = update_header_sync(bs); + if (ret < 0) { + goto fail; + } + + if (old_size > 0) { + qcow2_free_clusters(bs, old_offset, old_size, QCOW2_DISCARD_OTHER); + } + + return 0; + +fail: + if (new_offset > 0) { + qcow2_free_clusters(bs, new_offset, new_size, QCOW2_DISCARD_OTHER); + } + + s->bitmap_directory_offset = old_offset; + s->bitmap_directory_size = old_size; + s->nb_bitmaps = old_nb_bitmaps; + s->autoclear_features = old_autocl; + + return ret; +} + /* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */ static void release_dirty_bitmap_helper(gpointer bitmap, gpointer bs) @@ -713,3 +884,311 @@ fail: g_slist_free(created_dirty_bitmaps); bitmap_list_free(bm_list); } + +/* store_bitmap_data() + * Store bitmap to image, filling bitmap table accordingly. + */ +static uint64_t *store_bitmap_data(BlockDriverState *bs, + BdrvDirtyBitmap *bitmap, + uint32_t *bitmap_table_size, Error **errp) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + int64_t sector; + uint64_t dsc; + uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap); + const char *bm_name = bdrv_dirty_bitmap_name(bitmap); + uint8_t *buf = NULL; + BdrvDirtyBitmapIter *dbi; + uint64_t *tb; + uint64_t tb_size = + size_to_clusters(s, + bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size)); + + if (tb_size > BME_MAX_TABLE_SIZE || + tb_size * s->cluster_size > BME_MAX_PHYS_SIZE) + { + error_setg(errp, "Bitmap '%s' is too big", bm_name); + return NULL; + } + + tb = g_try_new0(uint64_t, tb_size); + if (tb == NULL) { + error_setg(errp, "No memory"); + return NULL; + } + + dbi = bdrv_dirty_iter_new(bitmap, 0); + buf = g_malloc(s->cluster_size); + dsc = disk_sectors_in_bitmap_cluster(s, bitmap); + assert(DIV_ROUND_UP(bm_size, dsc) == tb_size); + + while ((sector = bdrv_dirty_iter_next(dbi)) != -1) { + uint64_t cluster = sector / dsc; + uint64_t end, write_size; + int64_t off; + + sector = cluster * dsc; + end = MIN(bm_size, sector + dsc); + write_size = + bdrv_dirty_bitmap_serialization_size(bitmap, sector, end - sector); + assert(write_size <= s->cluster_size); + + off = qcow2_alloc_clusters(bs, s->cluster_size); + if (off < 0) { + error_setg_errno(errp, -off, + "Failed to allocate clusters for bitmap '%s'", + bm_name); + goto fail; + } + tb[cluster] = off; + + bdrv_dirty_bitmap_serialize_part(bitmap, buf, sector, end - sector); + if (write_size < s->cluster_size) { + memset(buf + write_size, 0, s->cluster_size - write_size); + } + + ret = qcow2_pre_write_overlap_check(bs, 0, off, s->cluster_size); + if (ret < 0) { + error_setg_errno(errp, -ret, "Qcow2 overlap check failed"); + goto fail; + } + + ret = bdrv_pwrite(bs->file, off, buf, s->cluster_size); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file", + bm_name); + goto fail; + } + + if (end >= bm_size) { + break; + } + + bdrv_set_dirty_iter(dbi, end); + } + + *bitmap_table_size = tb_size; + g_free(buf); + bdrv_dirty_iter_free(dbi); + + return tb; + +fail: + clear_bitmap_table(bs, tb, tb_size); + g_free(buf); + bdrv_dirty_iter_free(dbi); + g_free(tb); + + return NULL; +} + +/* store_bitmap() + * Store bm->dirty_bitmap to qcow2. + * Set bm->table_offset and bm->table_size accordingly. + */ +static int store_bitmap(BlockDriverState *bs, Qcow2Bitmap *bm, Error **errp) +{ + int ret; + uint64_t *tb; + int64_t tb_offset; + uint32_t tb_size; + BdrvDirtyBitmap *bitmap = bm->dirty_bitmap; + const char *bm_name; + + assert(bitmap != NULL); + + bm_name = bdrv_dirty_bitmap_name(bitmap); + + tb = store_bitmap_data(bs, bitmap, &tb_size, errp); + if (tb == NULL) { + g_free(tb); + return -EINVAL; + } + + assert(tb_size <= BME_MAX_TABLE_SIZE); + tb_offset = qcow2_alloc_clusters(bs, tb_size * sizeof(tb[0])); + if (tb_offset < 0) { + error_setg_errno(errp, -tb_offset, + "Failed to allocate clusters for bitmap '%s'", + bm_name); + goto fail; + } + + ret = qcow2_pre_write_overlap_check(bs, 0, tb_offset, + tb_size * sizeof(tb[0])); + if (ret < 0) { + error_setg_errno(errp, -ret, "Qcow2 overlap check failed"); + goto fail; + } + + bitmap_table_to_be(tb, tb_size); + ret = bdrv_pwrite(bs->file, tb_offset, tb, tb_size * sizeof(tb[0])); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file", + bm_name); + goto fail; + } + + g_free(tb); + + bm->table.offset = tb_offset; + bm->table.size = tb_size; + + return 0; + +fail: + clear_bitmap_table(bs, tb, tb_size); + + if (tb_offset > 0) { + qcow2_free_clusters(bs, tb_offset, tb_size * sizeof(tb[0]), + QCOW2_DISCARD_OTHER); + } + + g_free(tb); + + return ret; +} + +static Qcow2Bitmap *find_bitmap_by_name(Qcow2BitmapList *bm_list, + const char *name) +{ + Qcow2Bitmap *bm; + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + if (strcmp(name, bm->name) == 0) { + return bm; + } + } + + return NULL; +} + +void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp) +{ + BdrvDirtyBitmap *bitmap; + BDRVQcow2State *s = bs->opaque; + uint32_t new_nb_bitmaps = s->nb_bitmaps; + uint64_t new_dir_size = s->bitmap_directory_size; + int ret; + Qcow2BitmapList *bm_list; + Qcow2Bitmap *bm; + Qcow2BitmapTableList drop_tables; + Qcow2BitmapTable *tb, *tb_next; + + QSIMPLEQ_INIT(&drop_tables); + + if (!can_write(bs)) { + error_setg(errp, "No write access"); + return; + } + + if (!bdrv_has_persistent_bitmaps(bs)) { + /* nothing to do */ + return; + } + + if (s->nb_bitmaps == 0) { + bm_list = bitmap_list_new(); + } else { + bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, + s->bitmap_directory_size, errp); + if (bm_list == NULL) { + /* errp is already set */ + return; + } + } + + /* check constraints and names */ + for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap != NULL; + bitmap = bdrv_dirty_bitmap_next(bs, bitmap)) + { + const char *name = bdrv_dirty_bitmap_name(bitmap); + uint32_t granularity = bdrv_dirty_bitmap_granularity(bitmap); + Qcow2Bitmap *bm; + + if (!bdrv_dirty_bitmap_get_persistance(bitmap)) { + continue; + } + + if (check_constraints_on_bitmap(bs, name, granularity) < 0) { + error_setg(errp, "Bitmap '%s' doesn't satisfy the constraints", + name); + goto fail; + } + + bm = find_bitmap_by_name(bm_list, name); + if (bm == NULL) { + if (++new_nb_bitmaps > QCOW2_MAX_BITMAPS) { + error_setg(errp, "Too many persistent bitmaps"); + goto fail; + } + + new_dir_size += calc_dir_entry_size(strlen(name), 0); + if (new_dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { + error_setg(errp, "Too large bitmap directory"); + goto fail; + } + + bm = g_new0(Qcow2Bitmap, 1); + bm->name = g_strdup(name); + QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry); + } else { + if (!(bm->flags & BME_FLAG_IN_USE)) { + error_setg(errp, "Bitmap '%s' already exists in the image", + name); + goto fail; + } + tb = g_memdup(&bm->table, sizeof(bm->table)); + bm->table.offset = 0; + bm->table.size = 0; + QSIMPLEQ_INSERT_TAIL(&drop_tables, tb, entry); + } + bm->flags = bdrv_dirty_bitmap_get_autoload(bitmap) ? BME_FLAG_AUTO : 0; + bm->granularity_bits = ctz32(bdrv_dirty_bitmap_granularity(bitmap)); + bm->dirty_bitmap = bitmap; + } + + /* allocate clusters and store bitmaps */ + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + if (bm->dirty_bitmap == NULL) { + continue; + } + + ret = store_bitmap(bs, bm, errp); + if (ret < 0) { + goto fail; + } + } + + ret = update_ext_header_and_dir(bs, bm_list); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to update bitmap extension"); + goto fail; + } + + /* Bitmap directory was successfully updated, so, old data can be dropped. + * TODO it is better to reuse these clusters */ + QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) { + free_bitmap_clusters(bs, tb); + g_free(tb); + } + + bitmap_list_free(bm_list); + return; + +fail: + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + if (bm->dirty_bitmap == NULL || bm->table.offset == 0) { + continue; + } + + free_bitmap_clusters(bs, &bm->table); + } + + QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) { + g_free(tb); + } + + bitmap_list_free(bm_list); +} diff --git a/block/qcow2.c b/block/qcow2.c index 9f64753138..af580d2299 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -3542,6 +3542,7 @@ BlockDriver bdrv_qcow2 = { .bdrv_attach_aio_context = qcow2_attach_aio_context, .bdrv_load_autoloading_dirty_bitmaps = qcow2_load_autoloading_dirty_bitmaps, + .bdrv_store_persistent_dirty_bitmaps = qcow2_store_persistent_dirty_bitmaps, }; static void bdrv_qcow2_init(void) diff --git a/block/qcow2.h b/block/qcow2.h index bcedf5bdf2..d9a7643a60 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -615,5 +615,6 @@ void qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); /* qcow2-bitmap.c functions */ void qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp); +void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp); #endif -- 2.11.0