diff options
| -rw-r--r-- | block/qcow2-bitmap.c | 389 | ||||
| -rw-r--r-- | block/qcow2.c | 17 | ||||
| -rw-r--r-- | block/qcow2.h | 2 |
3 files changed, 406 insertions, 2 deletions
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index b8e472b3e8..2c7b057e21 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -44,6 +44,8 @@ /* Bitmap directory entry flags */ #define BME_RESERVED_FLAGS 0xfffffffcU +#define BME_FLAG_IN_USE (1U << 0) +#define BME_FLAG_AUTO (1U << 1) /* bits [1, 8] U [56, 63] are reserved */ #define BME_TABLE_ENTRY_RESERVED_MASK 0xff000000000001feULL @@ -85,6 +87,23 @@ typedef enum BitmapType { BT_DIRTY_TRACKING_BITMAP = 1 } BitmapType; +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; + } + + return bdrv_flush(bs); +} + static int check_table_entry(uint64_t entry, int cluster_size) { uint64_t offset; @@ -146,6 +165,120 @@ fail: return ret; } +/* This function returns the number of disk sectors covered by a single qcow2 + * cluster of bitmap data. */ +static uint64_t sectors_covered_by_bitmap_cluster(const BDRVQcow2State *s, + const BdrvDirtyBitmap *bitmap) +{ + uint32_t sector_granularity = + bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS; + + return (uint64_t)sector_granularity * (s->cluster_size << 3); +} + +/* load_bitmap_data + * @bitmap_table entries must satisfy specification constraints. + * @bitmap must be cleared */ +static int load_bitmap_data(BlockDriverState *bs, + const uint64_t *bitmap_table, + uint32_t bitmap_table_size, + BdrvDirtyBitmap *bitmap) +{ + int ret = 0; + BDRVQcow2State *s = bs->opaque; + uint64_t sector, sbc; + uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap); + uint8_t *buf = NULL; + uint64_t i, tab_size = + size_to_clusters(s, + bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size)); + + if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) { + return -EINVAL; + } + + buf = g_malloc(s->cluster_size); + sbc = sectors_covered_by_bitmap_cluster(s, bitmap); + for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) { + uint64_t count = MIN(bm_size - sector, sbc); + uint64_t entry = bitmap_table[i]; + uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK; + + assert(check_table_entry(entry, s->cluster_size) == 0); + + if (offset == 0) { + if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) { + bdrv_dirty_bitmap_deserialize_ones(bitmap, sector, count, + false); + } else { + /* No need to deserialize zeros because the dirty bitmap is + * already cleared */ + } + } else { + ret = bdrv_pread(bs->file, offset, buf, s->cluster_size); + if (ret < 0) { + goto finish; + } + bdrv_dirty_bitmap_deserialize_part(bitmap, buf, sector, count, + false); + } + } + ret = 0; + + bdrv_dirty_bitmap_deserialize_finish(bitmap); + +finish: + g_free(buf); + + return ret; +} + +static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs, + Qcow2Bitmap *bm, Error **errp) +{ + int ret; + uint64_t *bitmap_table = NULL; + uint32_t granularity; + BdrvDirtyBitmap *bitmap = NULL; + + if (bm->flags & BME_FLAG_IN_USE) { + error_setg(errp, "Bitmap '%s' is in use", bm->name); + goto fail; + } + + 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 " + "bitmap '%s'", bm->name); + goto fail; + } + + granularity = 1U << bm->granularity_bits; + bitmap = bdrv_create_dirty_bitmap(bs, granularity, bm->name, errp); + if (bitmap == NULL) { + goto fail; + } + + 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", + bm->name); + goto fail; + } + + g_free(bitmap_table); + return bitmap; + +fail: + g_free(bitmap_table); + if (bitmap != NULL) { + bdrv_release_dirty_bitmap(bs, bitmap); + } + + return NULL; +} + /* * Bitmap List */ @@ -164,6 +297,15 @@ static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry) be32_to_cpus(&entry->extra_data_size); } +static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry) +{ + cpu_to_be64s(&entry->bitmap_table_offset); + cpu_to_be32s(&entry->bitmap_table_size); + cpu_to_be32s(&entry->flags); + cpu_to_be16s(&entry->name_size); + cpu_to_be32s(&entry->extra_data_size); +} + static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size) { return align_offset(sizeof(Qcow2BitmapDirEntry) + @@ -224,6 +366,17 @@ static int check_dir_entry(BlockDriverState *bs, Qcow2BitmapDirEntry *entry) return fail ? -EINVAL : 0; } +static inline void bitmap_directory_to_be(uint8_t *dir, size_t size) +{ + uint8_t *end = dir + size; + while (dir < end) { + Qcow2BitmapDirEntry *e = (Qcow2BitmapDirEntry *)dir; + dir += dir_entry_size(e); + + bitmap_dir_entry_to_be(e); + } +} + /* * Bitmap List public functions */ @@ -258,6 +411,18 @@ static Qcow2BitmapList *bitmap_list_new(void) return bm_list; } +static uint32_t bitmap_list_count(Qcow2BitmapList *bm_list) +{ + Qcow2Bitmap *bm; + uint32_t nb_bitmaps = 0; + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + nb_bitmaps++; + } + + return nb_bitmaps; +} + /* bitmap_list_load * Get bitmap list from qcow2 image. Actually reads bitmap directory, * checks it and convert to bitmap list. @@ -437,3 +602,227 @@ out: return ret; } + +/* bitmap_list_store + * Store bitmap list to qcow2 image as a bitmap directory. + * Everything is checked. + */ +static int bitmap_list_store(BlockDriverState *bs, Qcow2BitmapList *bm_list, + uint64_t *offset, uint64_t *size, bool in_place) +{ + int ret; + uint8_t *dir; + int64_t dir_offset = 0; + uint64_t dir_size = 0; + Qcow2Bitmap *bm; + Qcow2BitmapDirEntry *e; + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + dir_size += calc_dir_entry_size(strlen(bm->name), 0); + } + + if (dir_size == 0 || dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { + return -EINVAL; + } + + if (in_place) { + if (*size != dir_size || *offset == 0) { + return -EINVAL; + } + + dir_offset = *offset; + } + + dir = g_try_malloc(dir_size); + if (dir == NULL) { + return -ENOMEM; + } + + e = (Qcow2BitmapDirEntry *)dir; + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + 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; + e->name_size = strlen(bm->name); + e->extra_data_size = 0; + memcpy(e + 1, bm->name, e->name_size); + + if (check_dir_entry(bs, e) < 0) { + ret = -EINVAL; + goto fail; + } + + e = next_dir_entry(e); + } + + bitmap_directory_to_be(dir, dir_size); + + if (!in_place) { + dir_offset = qcow2_alloc_clusters(bs, dir_size); + if (dir_offset < 0) { + ret = dir_offset; + goto fail; + } + } + + ret = qcow2_pre_write_overlap_check(bs, 0, dir_offset, dir_size); + if (ret < 0) { + goto fail; + } + + ret = bdrv_pwrite(bs->file, dir_offset, dir, dir_size); + if (ret < 0) { + goto fail; + } + + g_free(dir); + + if (!in_place) { + *size = dir_size; + *offset = dir_offset; + } + + return 0; + +fail: + g_free(dir); + + if (!in_place && dir_offset > 0) { + qcow2_free_clusters(bs, dir_offset, dir_size, QCOW2_DISCARD_OTHER); + } + + return ret; +} + +/* + * Bitmap List end + */ + +static int update_ext_header_and_dir_in_place(BlockDriverState *bs, + Qcow2BitmapList *bm_list) +{ + BDRVQcow2State *s = bs->opaque; + int ret; + + if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS) || + bm_list == NULL || QSIMPLEQ_EMPTY(bm_list) || + bitmap_list_count(bm_list) != s->nb_bitmaps) + { + return -EINVAL; + } + + s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS; + ret = update_header_sync(bs); + if (ret < 0) { + /* Two variants are possible here: + * 1. Autoclear flag is dropped, all bitmaps will be lost. + * 2. Autoclear flag is not dropped, old state is left. + */ + return ret; + } + + /* autoclear bit is not set, so we can safely update bitmap directory */ + + ret = bitmap_list_store(bs, bm_list, &s->bitmap_directory_offset, + &s->bitmap_directory_size, true); + if (ret < 0) { + /* autoclear bit is cleared, so all leaked clusters would be removed on + * qemu-img check */ + return ret; + } + + ret = update_header_sync(bs); + if (ret < 0) { + /* autoclear bit is cleared, so all leaked clusters would be removed on + * qemu-img check */ + return ret; + } + + s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS; + return update_header_sync(bs); + /* If final update_header_sync() fails, two variants are possible: + * 1. Autoclear flag is not set, all bitmaps will be lost. + * 2. Autoclear flag is set, header and directory are successfully updated. + */ +} + +/* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */ +static void release_dirty_bitmap_helper(gpointer bitmap, + gpointer bs) +{ + bdrv_release_dirty_bitmap(bs, bitmap); +} + +/* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */ +static void set_readonly_helper(gpointer bitmap, gpointer value) +{ + bdrv_dirty_bitmap_set_readonly(bitmap, (bool)value); +} + +/* qcow2_load_autoloading_dirty_bitmaps() + * Return value is a hint for caller: true means that the Qcow2 header was + * updated. (false doesn't mean that the header should be updated by the + * caller, it just means that updating was not needed or the image cannot be + * written to). + * On failure the function returns false. + */ +bool qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + Qcow2BitmapList *bm_list; + Qcow2Bitmap *bm; + GSList *created_dirty_bitmaps = NULL; + bool header_updated = false; + + if (s->nb_bitmaps == 0) { + /* No bitmaps - nothing to do */ + return false; + } + + bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, + s->bitmap_directory_size, errp); + if (bm_list == NULL) { + return false; + } + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + if ((bm->flags & BME_FLAG_AUTO) && !(bm->flags & BME_FLAG_IN_USE)) { + BdrvDirtyBitmap *bitmap = load_bitmap(bs, bm, errp); + if (bitmap == NULL) { + goto fail; + } + bm->flags |= BME_FLAG_IN_USE; + created_dirty_bitmaps = + g_slist_append(created_dirty_bitmaps, bitmap); + } + } + + if (created_dirty_bitmaps != NULL) { + if (can_write(bs)) { + /* in_use flags must be updated */ + int ret = update_ext_header_and_dir_in_place(bs, bm_list); + if (ret < 0) { + error_setg_errno(errp, -ret, "Can't update bitmap directory"); + goto fail; + } + header_updated = true; + } else { + g_slist_foreach(created_dirty_bitmaps, set_readonly_helper, + (gpointer)true); + } + } + + g_slist_free(created_dirty_bitmaps); + bitmap_list_free(bm_list); + + return header_updated; + +fail: + g_slist_foreach(created_dirty_bitmaps, release_dirty_bitmap_helper, bs); + g_slist_free(created_dirty_bitmaps); + bitmap_list_free(bm_list); + + return false; +} diff --git a/block/qcow2.c b/block/qcow2.c index 8688fdd8eb..8645b08fd3 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1445,9 +1445,22 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, /* Clear unknown autoclear feature bits */ update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; - - if (update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE)) { + update_header = + update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE); + if (update_header) { s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; + } + + if (qcow2_load_autoloading_dirty_bitmaps(bs, &local_err)) { + update_header = false; + } + if (local_err != NULL) { + error_propagate(errp, local_err); + ret = -EINVAL; + goto fail; + } + + if (update_header) { ret = qcow2_update_header(bs); if (ret < 0) { error_setg_errno(errp, -ret, "Could not update qcow2 header"); diff --git a/block/qcow2.h b/block/qcow2.h index 348864860b..886480b018 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -645,4 +645,6 @@ void qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res, void **refcount_table, int64_t *refcount_table_size); +bool qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp); + #endif |