diff options
Diffstat (limited to 'block/qcow2-bitmap.c')
| -rw-r--r-- | block/qcow2-bitmap.c | 1798 |
1 files changed, 1798 insertions, 0 deletions
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c new file mode 100644 index 000000000..8fb473155 --- /dev/null +++ b/block/qcow2-bitmap.c @@ -0,0 +1,1798 @@ +/* + * Bitmaps for the QCOW version 2 format + * + * Copyright (c) 2014-2017 Vladimir Sementsov-Ogievskiy + * + * This file is derived from qcow2-snapshot.c, original copyright: + * Copyright (c) 2004-2006 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "qemu/cutils.h" + +#include "qcow2.h" + +/* NOTICE: BME here means Bitmaps Extension and used as a namespace for + * _internal_ constants. Please do not use this _internal_ abbreviation for + * other needs and/or outside of this file. */ + +/* Bitmap directory entry constraints */ +#define BME_MAX_TABLE_SIZE 0x8000000 +#define BME_MAX_PHYS_SIZE 0x20000000 /* restrict BdrvDirtyBitmap size in RAM */ +#define BME_MAX_GRANULARITY_BITS 31 +#define BME_MIN_GRANULARITY_BITS 9 +#define BME_MAX_NAME_SIZE 1023 + +/* Size of bitmap table entries */ +#define BME_TABLE_ENTRY_SIZE (sizeof(uint64_t)) + +QEMU_BUILD_BUG_ON(BME_MAX_NAME_SIZE != BDRV_BITMAP_MAX_NAME_SIZE); + +#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 (1U << 0) +#define BME_FLAG_AUTO (1U << 1) + +/* bits [1, 8] U [56, 63] are reserved */ +#define BME_TABLE_ENTRY_RESERVED_MASK 0xff000000000001feULL +#define BME_TABLE_ENTRY_OFFSET_MASK 0x00fffffffffffe00ULL +#define BME_TABLE_ENTRY_FLAG_ALL_ONES (1ULL << 0) + +typedef struct QEMU_PACKED Qcow2BitmapDirEntry { + /* header is 8 byte aligned */ + uint64_t bitmap_table_offset; + + uint32_t bitmap_table_size; + uint32_t flags; + + uint8_t type; + uint8_t granularity_bits; + uint16_t name_size; + uint32_t extra_data_size; + /* extra data follows */ + /* name follows */ +} Qcow2BitmapDirEntry; + +typedef struct Qcow2BitmapTable { + uint64_t offset; + uint32_t size; /* number of 64bit entries */ + QSIMPLEQ_ENTRY(Qcow2BitmapTable) entry; +} Qcow2BitmapTable; + +typedef struct Qcow2Bitmap { + 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; + +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->file->bs); +} + +static inline void bitmap_table_to_be(uint64_t *bitmap_table, size_t size) +{ + size_t i; + + for (i = 0; i < size; ++i) { + bitmap_table[i] = cpu_to_be64(bitmap_table[i]); + } +} + +static int check_table_entry(uint64_t entry, int cluster_size) +{ + uint64_t offset; + + if (entry & BME_TABLE_ENTRY_RESERVED_MASK) { + return -EINVAL; + } + + offset = entry & BME_TABLE_ENTRY_OFFSET_MASK; + if (offset != 0) { + /* if offset specified, bit 0 is reserved */ + if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) { + return -EINVAL; + } + + if (offset % cluster_size != 0) { + return -EINVAL; + } + } + + return 0; +} + +static int64_t get_bitmap_bytes_needed(int64_t len, uint32_t granularity) +{ + int64_t num_bits = DIV_ROUND_UP(len, granularity); + + return DIV_ROUND_UP(num_bits, 8); +} + +static int check_constraints_on_bitmap(BlockDriverState *bs, + const char *name, + uint32_t granularity, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + int granularity_bits = ctz32(granularity); + int64_t len = bdrv_getlength(bs); + int64_t bitmap_bytes; + + assert(granularity > 0); + assert((granularity & (granularity - 1)) == 0); + + if (len < 0) { + error_setg_errno(errp, -len, "Failed to get size of '%s'", + bdrv_get_device_or_node_name(bs)); + return len; + } + + if (granularity_bits > BME_MAX_GRANULARITY_BITS) { + error_setg(errp, "Granularity exceeds maximum (%llu bytes)", + 1ULL << BME_MAX_GRANULARITY_BITS); + return -EINVAL; + } + if (granularity_bits < BME_MIN_GRANULARITY_BITS) { + error_setg(errp, "Granularity is under minimum (%llu bytes)", + 1ULL << BME_MIN_GRANULARITY_BITS); + return -EINVAL; + } + + bitmap_bytes = get_bitmap_bytes_needed(len, granularity); + if ((bitmap_bytes > (uint64_t)BME_MAX_PHYS_SIZE) || + (bitmap_bytes > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size)) + { + error_setg(errp, "Too much space will be occupied by the bitmap. " + "Use larger granularity"); + return -EINVAL; + } + + if (strlen(name) > BME_MAX_NAME_SIZE) { + error_setg(errp, "Name length exceeds maximum (%u characters)", + BME_MAX_NAME_SIZE); + return -EINVAL; + } + + return 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_ALWAYS); + bitmap_table[i] = 0; + } +} + +static int bitmap_table_load(BlockDriverState *bs, Qcow2BitmapTable *tb, + uint64_t **bitmap_table) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + uint32_t i; + uint64_t *table; + + assert(tb->size != 0); + table = g_try_new(uint64_t, tb->size); + if (table == NULL) { + return -ENOMEM; + } + + assert(tb->size <= BME_MAX_TABLE_SIZE); + ret = bdrv_pread(bs->file, tb->offset, + table, tb->size * BME_TABLE_ENTRY_SIZE); + if (ret < 0) { + goto fail; + } + + for (i = 0; i < tb->size; ++i) { + table[i] = be64_to_cpu(table[i]); + ret = check_table_entry(table[i], s->cluster_size); + if (ret < 0) { + goto fail; + } + } + + *bitmap_table = table; + return 0; + +fail: + g_free(table); + + 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) { + return ret; + } + + clear_bitmap_table(bs, bitmap_table, tb->size); + qcow2_free_clusters(bs, tb->offset, tb->size * BME_TABLE_ENTRY_SIZE, + QCOW2_DISCARD_OTHER); + g_free(bitmap_table); + + tb->offset = 0; + tb->size = 0; + + return 0; +} + +/* 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 offset, limit; + 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); + limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap); + for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) { + uint64_t count = MIN(bm_size - offset, limit); + uint64_t entry = bitmap_table[i]; + uint64_t data_offset = entry & BME_TABLE_ENTRY_OFFSET_MASK; + + assert(check_table_entry(entry, s->cluster_size) == 0); + + if (data_offset == 0) { + if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) { + bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count, + false); + } else { + /* No need to deserialize zeros because the dirty bitmap is + * already cleared */ + } + } else { + ret = bdrv_pread(bs->file, data_offset, buf, s->cluster_size); + if (ret < 0) { + goto finish; + } + bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, 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; + + granularity = 1U << bm->granularity_bits; + bitmap = bdrv_create_dirty_bitmap(bs, granularity, bm->name, errp); + if (bitmap == NULL) { + goto fail; + } + + if (bm->flags & BME_FLAG_IN_USE) { + /* Data is unusable, skip loading it */ + return bitmap; + } + + 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; + } + + 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(bitmap); + } + + return NULL; +} + +/* + * Bitmap List + */ + +/* + * Bitmap List private functions + * Only Bitmap List knows about bitmap directory structure in Qcow2. + */ + +static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry) +{ + entry->bitmap_table_offset = be64_to_cpu(entry->bitmap_table_offset); + entry->bitmap_table_size = be32_to_cpu(entry->bitmap_table_size); + entry->flags = be32_to_cpu(entry->flags); + entry->name_size = be16_to_cpu(entry->name_size); + entry->extra_data_size = be32_to_cpu(entry->extra_data_size); +} + +static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry) +{ + entry->bitmap_table_offset = cpu_to_be64(entry->bitmap_table_offset); + entry->bitmap_table_size = cpu_to_be32(entry->bitmap_table_size); + entry->flags = cpu_to_be32(entry->flags); + entry->name_size = cpu_to_be16(entry->name_size); + entry->extra_data_size = cpu_to_be32(entry->extra_data_size); +} + +static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size) +{ + int size = sizeof(Qcow2BitmapDirEntry) + name_size + extra_data_size; + return ROUND_UP(size, 8); +} + +static inline int dir_entry_size(Qcow2BitmapDirEntry *entry) +{ + return calc_dir_entry_size(entry->name_size, entry->extra_data_size); +} + +static inline const char *dir_entry_name_field(Qcow2BitmapDirEntry *entry) +{ + return (const char *)(entry + 1) + entry->extra_data_size; +} + +static inline char *dir_entry_copy_name(Qcow2BitmapDirEntry *entry) +{ + const char *name_field = dir_entry_name_field(entry); + return g_strndup(name_field, entry->name_size); +} + +static inline Qcow2BitmapDirEntry *next_dir_entry(Qcow2BitmapDirEntry *entry) +{ + return (Qcow2BitmapDirEntry *)((uint8_t *)entry + dir_entry_size(entry)); +} + +static int check_dir_entry(BlockDriverState *bs, Qcow2BitmapDirEntry *entry) +{ + BDRVQcow2State *s = bs->opaque; + uint64_t phys_bitmap_bytes; + int64_t len; + + bool fail = (entry->bitmap_table_size == 0) || + (entry->bitmap_table_offset == 0) || + (entry->bitmap_table_offset % s->cluster_size) || + (entry->bitmap_table_size > BME_MAX_TABLE_SIZE) || + (entry->granularity_bits > BME_MAX_GRANULARITY_BITS) || + (entry->granularity_bits < BME_MIN_GRANULARITY_BITS) || + (entry->flags & BME_RESERVED_FLAGS) || + (entry->name_size > BME_MAX_NAME_SIZE) || + (entry->type != BT_DIRTY_TRACKING_BITMAP); + + if (fail) { + return -EINVAL; + } + + phys_bitmap_bytes = (uint64_t)entry->bitmap_table_size * s->cluster_size; + len = bdrv_getlength(bs); + + if (len < 0) { + return len; + } + + if (phys_bitmap_bytes > BME_MAX_PHYS_SIZE) { + return -EINVAL; + } + + if (!(entry->flags & BME_FLAG_IN_USE) && + (len > ((phys_bitmap_bytes * 8) << entry->granularity_bits))) + { + /* + * We've loaded a valid bitmap (IN_USE not set) or we are going to + * store a valid bitmap, but the allocated bitmap table size is not + * enough to store this bitmap. + * + * Note, that it's OK to have an invalid bitmap with invalid size due + * to a bitmap that was not correctly saved after image resize. + */ + return -EINVAL; + } + + return 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 + */ + +static void bitmap_free(Qcow2Bitmap *bm) +{ + if (bm == NULL) { + return; + } + + g_free(bm->name); + g_free(bm); +} + +static void bitmap_list_free(Qcow2BitmapList *bm_list) +{ + Qcow2Bitmap *bm; + + if (bm_list == NULL) { + return; + } + + while ((bm = QSIMPLEQ_FIRST(bm_list)) != NULL) { + QSIMPLEQ_REMOVE_HEAD(bm_list, entry); + bitmap_free(bm); + } + + g_free(bm_list); +} + +static Qcow2BitmapList *bitmap_list_new(void) +{ + Qcow2BitmapList *bm_list = g_new(Qcow2BitmapList, 1); + QSIMPLEQ_INIT(bm_list); + + 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. + */ +static Qcow2BitmapList *bitmap_list_load(BlockDriverState *bs, uint64_t offset, + uint64_t size, Error **errp) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + uint8_t *dir, *dir_end; + Qcow2BitmapDirEntry *e; + uint32_t nb_dir_entries = 0; + Qcow2BitmapList *bm_list = NULL; + + if (size == 0) { + error_setg(errp, "Requested bitmap directory size is zero"); + return NULL; + } + + if (size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { + error_setg(errp, "Requested bitmap directory size is too big"); + return NULL; + } + + dir = g_try_malloc(size); + if (dir == NULL) { + error_setg(errp, "Failed to allocate space for bitmap directory"); + return NULL; + } + dir_end = dir + size; + + ret = bdrv_pread(bs->file, offset, dir, size); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to read bitmap directory"); + goto fail; + } + + bm_list = bitmap_list_new(); + for (e = (Qcow2BitmapDirEntry *)dir; + e < (Qcow2BitmapDirEntry *)dir_end; + e = next_dir_entry(e)) + { + Qcow2Bitmap *bm; + + if ((uint8_t *)(e + 1) > dir_end) { + goto broken_dir; + } + + if (++nb_dir_entries > s->nb_bitmaps) { + error_setg(errp, "More bitmaps found than specified in header" + " extension"); + goto fail; + } + bitmap_dir_entry_to_cpu(e); + + if ((uint8_t *)next_dir_entry(e) > dir_end) { + goto broken_dir; + } + + if (e->extra_data_size != 0) { + error_setg(errp, "Bitmap extra data is not supported"); + goto fail; + } + + ret = check_dir_entry(bs, e); + if (ret < 0) { + error_setg(errp, "Bitmap '%.*s' doesn't satisfy the constraints", + e->name_size, dir_entry_name_field(e)); + goto fail; + } + + bm = g_new0(Qcow2Bitmap, 1); + 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); + QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry); + } + + if (nb_dir_entries != s->nb_bitmaps) { + error_setg(errp, "Less bitmaps found than specified in header" + " extension"); + goto fail; + } + + if ((uint8_t *)e != dir_end) { + goto broken_dir; + } + + g_free(dir); + return bm_list; + +broken_dir: + error_setg(errp, "Broken bitmap directory"); + +fail: + g_free(dir); + bitmap_list_free(bm_list); + + return NULL; +} + +int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res, + void **refcount_table, + int64_t *refcount_table_size) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + Qcow2BitmapList *bm_list; + Qcow2Bitmap *bm; + + if (s->nb_bitmaps == 0) { + return 0; + } + + ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, refcount_table_size, + s->bitmap_directory_offset, + s->bitmap_directory_size); + if (ret < 0) { + return ret; + } + + bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, + s->bitmap_directory_size, NULL); + if (bm_list == NULL) { + res->corruptions++; + return -EINVAL; + } + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + uint64_t *bitmap_table = NULL; + int i; + + ret = qcow2_inc_refcounts_imrt(bs, res, + refcount_table, refcount_table_size, + bm->table.offset, + bm->table.size * BME_TABLE_ENTRY_SIZE); + if (ret < 0) { + goto out; + } + + ret = bitmap_table_load(bs, &bm->table, &bitmap_table); + if (ret < 0) { + res->corruptions++; + goto out; + } + + for (i = 0; i < bm->table.size; ++i) { + uint64_t entry = bitmap_table[i]; + uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK; + + if (check_table_entry(entry, s->cluster_size) < 0) { + res->corruptions++; + continue; + } + + if (offset == 0) { + continue; + } + + ret = qcow2_inc_refcounts_imrt(bs, res, + refcount_table, refcount_table_size, + offset, s->cluster_size); + if (ret < 0) { + g_free(bitmap_table); + goto out; + } + } + + g_free(bitmap_table); + } + +out: + bitmap_list_free(bm_list); + + 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_malloc0(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; + } + } + + /* Actually, even in in-place case ignoring QCOW2_OL_BITMAP_DIRECTORY is not + * necessary, because we drop QCOW2_AUTOCLEAR_BITMAPS when updating bitmap + * directory in-place (actually, turn-off the extension), which is checked + * in qcow2_check_metadata_overlap() */ + ret = qcow2_pre_write_overlap_check( + bs, in_place ? QCOW2_OL_BITMAP_DIRECTORY : 0, dir_offset, dir_size, + false); + 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. + */ +} + +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 = qcow2_flush_caches(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) +{ + bdrv_release_dirty_bitmap(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); +} + +/* + * Return true on success, false on failure. + * If header_updated is not NULL then it is set appropriately regardless of + * the return value. + */ +bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, bool *header_updated, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + Qcow2BitmapList *bm_list; + Qcow2Bitmap *bm; + GSList *created_dirty_bitmaps = NULL; + bool needs_update = false; + + if (header_updated) { + *header_updated = false; + } + + if (s->nb_bitmaps == 0) { + /* No bitmaps - nothing to do */ + return true; + } + + 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) { + BdrvDirtyBitmap *bitmap; + + if ((bm->flags & BME_FLAG_IN_USE) && + bdrv_find_dirty_bitmap(bs, bm->name)) + { + /* + * We already have corresponding BdrvDirtyBitmap, and bitmap in the + * image is marked IN_USE. Firstly, this state is valid, no reason + * to consider existing BdrvDirtyBitmap to be bad. Secondly it's + * absolutely possible, when we do migration with shared storage + * with dirty-bitmaps capability enabled: if the bitmap was loaded + * from this storage before migration start, the storage will + * of-course contain IN_USE outdated version of the bitmap, and we + * should not load it on migration target, as we already have this + * bitmap, being migrated. + */ + continue; + } + + bitmap = load_bitmap(bs, bm, errp); + if (bitmap == NULL) { + goto fail; + } + + bdrv_dirty_bitmap_set_persistence(bitmap, true); + if (bm->flags & BME_FLAG_IN_USE) { + bdrv_dirty_bitmap_set_inconsistent(bitmap); + } else { + /* NB: updated flags only get written if can_write(bs) is true. */ + bm->flags |= BME_FLAG_IN_USE; + needs_update = true; + } + if (!(bm->flags & BME_FLAG_AUTO)) { + bdrv_disable_dirty_bitmap(bitmap); + } + created_dirty_bitmaps = + g_slist_append(created_dirty_bitmaps, bitmap); + } + + if (needs_update && 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; + } + if (header_updated) { + *header_updated = true; + } + } + + if (!can_write(bs)) { + g_slist_foreach(created_dirty_bitmaps, set_readonly_helper, + (gpointer)true); + } + + g_slist_free(created_dirty_bitmaps); + bitmap_list_free(bm_list); + + return true; + +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; +} + + +static Qcow2BitmapInfoFlagsList *get_bitmap_info_flags(uint32_t flags) +{ + Qcow2BitmapInfoFlagsList *list = NULL; + Qcow2BitmapInfoFlagsList **tail = &list; + int i; + + static const struct { + int bme; /* Bitmap directory entry flags */ + int info; /* The flags to report to the user */ + } map[] = { + { BME_FLAG_IN_USE, QCOW2_BITMAP_INFO_FLAGS_IN_USE }, + { BME_FLAG_AUTO, QCOW2_BITMAP_INFO_FLAGS_AUTO }, + }; + + int map_size = ARRAY_SIZE(map); + + for (i = 0; i < map_size; ++i) { + if (flags & map[i].bme) { + QAPI_LIST_APPEND(tail, map[i].info); + flags &= ~map[i].bme; + } + } + /* Check if the BME_* mapping above is complete */ + assert(!flags); + + return list; +} + +/* + * qcow2_get_bitmap_info_list() + * Returns a list of QCOW2 bitmap details. + * On success return true with info_list set (note, that if there are no + * bitmaps, info_list is set to NULL). + * On failure return false with errp set. + */ +bool qcow2_get_bitmap_info_list(BlockDriverState *bs, + Qcow2BitmapInfoList **info_list, Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + Qcow2BitmapList *bm_list; + Qcow2Bitmap *bm; + Qcow2BitmapInfoList **tail; + + if (s->nb_bitmaps == 0) { + *info_list = NULL; + return true; + } + + bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, + s->bitmap_directory_size, errp); + if (!bm_list) { + return false; + } + + *info_list = NULL; + tail = info_list; + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + Qcow2BitmapInfo *info = g_new0(Qcow2BitmapInfo, 1); + info->granularity = 1U << bm->granularity_bits; + info->name = g_strdup(bm->name); + info->flags = get_bitmap_info_flags(bm->flags & ~BME_RESERVED_FLAGS); + QAPI_LIST_APPEND(tail, info); + } + + bitmap_list_free(bm_list); + + return true; +} + +int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + Qcow2BitmapList *bm_list; + Qcow2Bitmap *bm; + GSList *ro_dirty_bitmaps = NULL; + int ret = -EINVAL; + bool need_header_update = false; + + if (s->nb_bitmaps == 0) { + /* No bitmaps - nothing to do */ + return 0; + } + + bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, + s->bitmap_directory_size, errp); + if (bm_list == NULL) { + return -EINVAL; + } + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name); + + if (!bitmap) { + error_setg(errp, "Unexpected bitmap '%s' in image '%s'", + bm->name, bs->filename); + goto out; + } + + if (!(bm->flags & BME_FLAG_IN_USE)) { + if (!bdrv_dirty_bitmap_readonly(bitmap)) { + error_setg(errp, "Corruption: bitmap '%s' is not marked IN_USE " + "in the image '%s' and not marked readonly in RAM", + bm->name, bs->filename); + goto out; + } + if (bdrv_dirty_bitmap_inconsistent(bitmap)) { + error_setg(errp, "Corruption: bitmap '%s' is inconsistent but " + "is not marked IN_USE in the image '%s'", bm->name, + bs->filename); + goto out; + } + + bm->flags |= BME_FLAG_IN_USE; + need_header_update = true; + } else { + /* + * What if flags already has BME_FLAG_IN_USE ? + * + * 1. if we are reopening RW -> RW it's OK, of course. + * 2. if we are reopening RO -> RW: + * 2.1 if @bitmap is inconsistent, it's OK. It means that it was + * inconsistent (IN_USE) when we loaded it + * 2.2 if @bitmap is not inconsistent. This seems to be impossible + * and implies third party interaction. Let's error-out for + * safety. + */ + if (bdrv_dirty_bitmap_readonly(bitmap) && + !bdrv_dirty_bitmap_inconsistent(bitmap)) + { + error_setg(errp, "Corruption: bitmap '%s' is marked IN_USE " + "in the image '%s' but it is readonly and " + "consistent in RAM", + bm->name, bs->filename); + goto out; + } + } + + if (bdrv_dirty_bitmap_readonly(bitmap)) { + ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap); + } + } + + if (need_header_update) { + if (!can_write(bs->file->bs) || !(bs->file->perm & BLK_PERM_WRITE)) { + error_setg(errp, "Failed to reopen bitmaps rw: no write access " + "the protocol file"); + goto out; + } + + /* in_use flags must be updated */ + ret = update_ext_header_and_dir_in_place(bs, bm_list); + if (ret < 0) { + error_setg_errno(errp, -ret, "Cannot update bitmap directory"); + goto out; + } + } + + g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false); + ret = 0; + +out: + g_slist_free(ro_dirty_bitmaps); + bitmap_list_free(bm_list); + + return ret; +} + +/* Checks to see if it's safe to resize bitmaps */ +int qcow2_truncate_bitmaps_check(BlockDriverState *bs, Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + Qcow2BitmapList *bm_list; + Qcow2Bitmap *bm; + int ret = 0; + + if (s->nb_bitmaps == 0) { + return 0; + } + + bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, + s->bitmap_directory_size, errp); + if (bm_list == NULL) { + return -EINVAL; + } + + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name); + if (bitmap == NULL) { + /* + * We rely on all bitmaps being in-memory to be able to resize them, + * Otherwise, we'd need to resize them on disk explicitly + */ + error_setg(errp, "Cannot resize qcow2 with persistent bitmaps that " + "were not loaded into memory"); + ret = -ENOTSUP; + goto out; + } + + /* + * The checks against readonly and busy are redundant, but certainly + * do no harm. checks against inconsistent are crucial: + */ + if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, errp)) { + ret = -ENOTSUP; + goto out; + } + } + +out: + bitmap_list_free(bm_list); + return ret; +} + +/* 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 offset; + uint64_t limit; + uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap); + const char *bm_name = bdrv_dirty_bitmap_name(bitmap); + uint8_t *buf = NULL; + 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; + } + + buf = g_malloc(s->cluster_size); + limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap); + assert(DIV_ROUND_UP(bm_size, limit) == tb_size); + + offset = 0; + while ((offset = bdrv_dirty_bitmap_next_dirty(bitmap, offset, INT64_MAX)) + >= 0) + { + uint64_t cluster = offset / limit; + uint64_t end, write_size; + int64_t off; + + /* + * We found the first dirty offset, but want to write out the + * entire cluster of the bitmap that includes that offset, + * including any leading zero bits. + */ + offset = QEMU_ALIGN_DOWN(offset, limit); + end = MIN(bm_size, offset + limit); + write_size = bdrv_dirty_bitmap_serialization_size(bitmap, offset, + end - offset); + 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, offset, end - offset); + 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, false); + 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; + } + + offset = end; + } + + *bitmap_table_size = tb_size; + g_free(buf); + + return tb; + +fail: + clear_bitmap_table(bs, tb, tb_size); + g_free(buf); + 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) { + 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); + ret = tb_offset; + goto fail; + } + + ret = qcow2_pre_write_overlap_check(bs, 0, tb_offset, + tb_size * sizeof(tb[0]), false); + 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; +} + +int coroutine_fn qcow2_co_remove_persistent_dirty_bitmap(BlockDriverState *bs, + const char *name, + Error **errp) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + Qcow2Bitmap *bm = NULL; + Qcow2BitmapList *bm_list; + + if (s->nb_bitmaps == 0) { + /* + * Absence of the bitmap is not an error: see explanation above + * bdrv_co_remove_persistent_dirty_bitmap() definition. + */ + return 0; + } + + qemu_co_mutex_lock(&s->lock); + + bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, + s->bitmap_directory_size, errp); + if (bm_list == NULL) { + ret = -EIO; + goto out; + } + + bm = find_bitmap_by_name(bm_list, name); + if (bm == NULL) { + /* Absence of the bitmap is not an error, see above. */ + ret = 0; + goto out; + } + + QSIMPLEQ_REMOVE(bm_list, bm, Qcow2Bitmap, entry); + + ret = update_ext_header_and_dir(bs, bm_list); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to update bitmap extension"); + goto out; + } + + free_bitmap_clusters(bs, &bm->table); + +out: + qemu_co_mutex_unlock(&s->lock); + + bitmap_free(bm); + bitmap_list_free(bm_list); + + return ret; +} + +/* + * qcow2_store_persistent_dirty_bitmaps + * + * Stores persistent BdrvDirtyBitmap objects. + * + * @release_stored: if true, release BdrvDirtyBitmap's after storing to the + * image. This is used in two cases, both via qcow2_inactivate: + * 1. bdrv_close: It's correct to remove bitmaps on close. + * 2. migration: If bitmaps are migrated through migration channel via + * 'dirty-bitmaps' migration capability they are not handled by this code. + * Otherwise, it's OK to drop BdrvDirtyBitmap's and reload them on + * invalidation. + * + * Anyway, it's correct to remove BdrvDirtyBitmap's on inactivation, as + * inactivation means that we lose control on disk, and therefore on bitmaps, + * we should sync them and do not touch more. + * + * Contrariwise, we don't want to release any bitmaps on just reopen-to-ro, + * when we need to store them, as image is still under our control, and it's + * good to keep all the bitmaps in read-only mode. Moreover, keeping them + * read-only is correct because this is what would happen if we opened the node + * readonly to begin with, and whether we opened directly or reopened to that + * state shouldn't matter for the state we get afterward. + */ +bool qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, + bool release_stored, Error **errp) +{ + ERRP_GUARD(); + 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; + QSIMPLEQ_HEAD(, Qcow2BitmapTable) drop_tables; + Qcow2BitmapTable *tb, *tb_next; + bool need_write = false; + + QSIMPLEQ_INIT(&drop_tables); + + 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) { + return false; + } + } + + /* check constraints and names */ + FOR_EACH_DIRTY_BITMAP(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_persistence(bitmap) || + bdrv_dirty_bitmap_inconsistent(bitmap)) { + continue; + } + + if (bdrv_dirty_bitmap_readonly(bitmap)) { + /* + * Store the bitmap in the associated Qcow2Bitmap so it + * can be released later + */ + bm = find_bitmap_by_name(bm_list, name); + if (bm) { + bm->dirty_bitmap = bitmap; + } + continue; + } + + need_write = true; + + if (check_constraints_on_bitmap(bs, name, granularity, errp) < 0) { + error_prepend(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, "Bitmap directory is too large"); + 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_enabled(bitmap) ? BME_FLAG_AUTO : 0; + bm->granularity_bits = ctz32(bdrv_dirty_bitmap_granularity(bitmap)); + bm->dirty_bitmap = bitmap; + } + + if (!need_write) { + goto success; + } + + if (!can_write(bs)) { + error_setg(errp, "No write access"); + goto fail; + } + + /* allocate clusters and store bitmaps */ + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + BdrvDirtyBitmap *bitmap = bm->dirty_bitmap; + + if (bitmap == NULL || bdrv_dirty_bitmap_readonly(bitmap)) { + 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); + } + +success: + if (release_stored) { + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + if (bm->dirty_bitmap == NULL) { + continue; + } + + bdrv_release_dirty_bitmap(bm->dirty_bitmap); + } + } + + bitmap_list_free(bm_list); + return true; + +fail: + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + if (bm->dirty_bitmap == NULL || bm->table.offset == 0 || + bdrv_dirty_bitmap_readonly(bm->dirty_bitmap)) + { + continue; + } + + free_bitmap_clusters(bs, &bm->table); + } + + QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) { + g_free(tb); + } + + bitmap_list_free(bm_list); + return false; +} + +int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp) +{ + BdrvDirtyBitmap *bitmap; + + if (!qcow2_store_persistent_dirty_bitmaps(bs, false, errp)) { + return -EINVAL; + } + + FOR_EACH_DIRTY_BITMAP(bs, bitmap) { + if (bdrv_dirty_bitmap_get_persistence(bitmap)) { + bdrv_dirty_bitmap_set_readonly(bitmap, true); + } + } + + return 0; +} + +bool coroutine_fn qcow2_co_can_store_new_dirty_bitmap(BlockDriverState *bs, + const char *name, + uint32_t granularity, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + BdrvDirtyBitmap *bitmap; + uint64_t bitmap_directory_size = 0; + uint32_t nb_bitmaps = 0; + + if (bdrv_find_dirty_bitmap(bs, name)) { + error_setg(errp, "Bitmap already exists: %s", name); + return false; + } + + if (s->qcow_version < 3) { + /* Without autoclear_features, we would always have to assume + * that a program without persistent dirty bitmap support has + * accessed this qcow2 file when opening it, and would thus + * have to drop all dirty bitmaps (defeating their purpose). + */ + error_setg(errp, "Cannot store dirty bitmaps in qcow2 v2 files"); + goto fail; + } + + if (check_constraints_on_bitmap(bs, name, granularity, errp) != 0) { + goto fail; + } + + FOR_EACH_DIRTY_BITMAP(bs, bitmap) { + if (bdrv_dirty_bitmap_get_persistence(bitmap)) { + nb_bitmaps++; + bitmap_directory_size += + calc_dir_entry_size(strlen(bdrv_dirty_bitmap_name(bitmap)), 0); + } + } + nb_bitmaps++; + bitmap_directory_size += calc_dir_entry_size(strlen(name), 0); + + if (nb_bitmaps > QCOW2_MAX_BITMAPS) { + error_setg(errp, + "Maximum number of persistent bitmaps is already reached"); + goto fail; + } + + if (bitmap_directory_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { + error_setg(errp, "Not enough space in the bitmap directory"); + goto fail; + } + + return true; + +fail: + error_prepend(errp, "Can't make bitmap '%s' persistent in '%s': ", + name, bdrv_get_device_or_node_name(bs)); + return false; +} + +bool qcow2_supports_persistent_dirty_bitmap(BlockDriverState *bs) +{ + BDRVQcow2State *s = bs->opaque; + + return s->qcow_version >= 3; +} + +/* + * Compute the space required to copy bitmaps from @in_bs. + * + * The computation is based as if copying to a new image with the + * given @cluster_size, which may differ from the cluster size in + * @in_bs; in fact, @in_bs might be something other than qcow2. + */ +uint64_t qcow2_get_persistent_dirty_bitmap_size(BlockDriverState *in_bs, + uint32_t cluster_size) +{ + uint64_t bitmaps_size = 0; + BdrvDirtyBitmap *bm; + size_t bitmap_dir_size = 0; + + FOR_EACH_DIRTY_BITMAP(in_bs, bm) { + if (bdrv_dirty_bitmap_get_persistence(bm)) { + const char *name = bdrv_dirty_bitmap_name(bm); + uint32_t granularity = bdrv_dirty_bitmap_granularity(bm); + uint64_t bmbytes = + get_bitmap_bytes_needed(bdrv_dirty_bitmap_size(bm), + granularity); + uint64_t bmclusters = DIV_ROUND_UP(bmbytes, cluster_size); + + /* Assume the entire bitmap is allocated */ + bitmaps_size += bmclusters * cluster_size; + /* Also reserve space for the bitmap table entries */ + bitmaps_size += ROUND_UP(bmclusters * BME_TABLE_ENTRY_SIZE, + cluster_size); + /* And space for contribution to bitmap directory size */ + bitmap_dir_size += calc_dir_entry_size(strlen(name), 0); + } + } + bitmaps_size += ROUND_UP(bitmap_dir_size, cluster_size); + + return bitmaps_size; +} |