Realize block bitmap storing interface, to allow qcow2 images store
persistent bitmaps.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
Reviewed-by: Max Reitz <mre...@redhat.com>
---
block/qcow2-bitmap.c | 489 +++++++++++++++++++++++++++++++++++++++++++++++++--
block/qcow2.c | 1 +
block/qcow2.h | 1 +
3 files changed, 476 insertions(+), 15 deletions(-)
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 9af658a0f4..151f5e9173 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 +72,22 @@ 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;
@@ -117,6 +131,15 @@ 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;
@@ -144,7 +167,50 @@ 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;
@@ -152,20 +218,20 @@ 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) {
@@ -182,6 +248,28 @@ 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,
@@ -263,7 +351,7 @@ 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 "
@@ -277,7 +365,7 @@ 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",
@@ -513,8 +601,8 @@ 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);
@@ -582,8 +670,8 @@ 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;
@@ -675,6 +763,69 @@ 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)
@@ -734,3 +885,311 @@ 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 5aeae1b36d..9cf1d9f8e7 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
