---
block.c | 19 +++++++++++++++++++
block/qcow2-cluster.c | 29 +++++++++++++++++++++++++++++
block/qcow2-snapshot.c | 33 +++++++++++++++++++++++----------
block/qcow2.c | 29 ++++++++++++++++++++---------
block/qcow2.h | 1 +
include/block/snapshot.h | 1 +
6 files changed, 93 insertions(+), 19 deletions(-)
diff --git a/block.c b/block.c
index 18a497f..b6f2004 100644
--- a/block.c
+++ b/block.c
@@ -2631,6 +2631,25 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
return ret;
}
+int bdrv_apply_snapshot(BlockDriverState *bs, const char *snapshot_id,
+ uint64_t snapshot_size)
+{
+ int ret = bdrv_snapshot_goto(bs, snapshot_id);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = refresh_total_sectors(bs, snapshot_size >> BDRV_SECTOR_BITS);
+ if (ret < 0) {
+ return ret;
+ }
+ bdrv_dirty_bitmap_truncate(bs);
+ if (bs->blk) {
+ blk_dev_resize_cb(bs->blk);
+ }
+ return ret;
+}
+
/**
* Length of a allocated file in bytes. Sparse files are counted by actual
* allocated space. Return < 0 if error or unknown.
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 31ecc10..f921fd8 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -31,6 +31,35 @@
#include "block/qcow2.h"
#include "trace.h"
+int shrink_l1_table(BlockDriverState *bs, int64_t new_l1_size)
+{
+ BDRVQcow2State *s = bs->opaque;
+ int64_t old_l1_size = s->l1_size;
+ s->l1_size = new_l1_size;
+ int ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset,
+ s->l1_size, 1);
+ if (ret < 0) {
+ return ret;
+ }
+
+ s->l1_size = old_l1_size;
+ ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset,
+ s->l1_size, -1);
+ if (ret < 0) {
+ return ret;
+ }
+ s->l1_size = new_l1_size;
+
+ uint32_t be_l1_size = cpu_to_be32(s->l1_size);
+ ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_size),
+ &be_l1_size, sizeof(be_l1_size));
+ if (ret < 0) {
+ return ret;
+ }
+
+ return 0;
+}
+
int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
bool exact_size)
{
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 5f4a17e..1ed0e18 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -477,13 +477,6 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
}
sn = &s->snapshots[snapshot_index];
- if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
- error_report("qcow2: Loading snapshots with different disk "
- "size is not implemented");
- ret = -ENOTSUP;
- goto fail;
- }
-
/*
* Make sure that the current L1 table is big enough to contain the whole
* L1 table of the snapshot. If the snapshot L1 table is smaller, the
@@ -505,7 +498,7 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
* Decrease the refcount referenced by the old one only when the L1
* table is overwritten.
*/
- sn_l1_table = g_try_malloc0(cur_l1_bytes);
+ sn_l1_table = g_try_malloc0(sn_l1_bytes);
if (cur_l1_bytes && sn_l1_table == NULL) {
ret = -ENOMEM;
goto fail;
@@ -530,11 +523,28 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
}
ret = bdrv_pwrite_sync(bs->file->bs, s->l1_table_offset, sn_l1_table,
- cur_l1_bytes);
+ sn_l1_bytes);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* write updated header.size */
+ uint64_t be_disk_size = cpu_to_be64(sn->disk_size);
+ ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size),
+ &be_disk_size, sizeof(uint64_t));
if (ret < 0) {
goto fail;
}
+ uint32_t be_l1_size = cpu_to_be32(sn->l1_size);
+ ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_size),
+ &be_l1_size, sizeof(be_l1_size));
+ if (ret < 0) {
+ goto fail;
+ }
+
+ s->l1_vm_state_index = sn->l1_size;
+
/*
* Decrease refcount of clusters of current L1 table.
*
@@ -552,7 +562,8 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
* Now update the in-memory L1 table to be in sync with the on-disk one. We
* need to do this even if updating refcounts failed.
*/
- for(i = 0;i < s->l1_size; i++) {
+ memset(s->l1_table, 0, s->l1_size * sizeof(uint64_t));
+ for (i = 0; i < sn->l1_size; i++) {
s->l1_table[i] = be64_to_cpu(sn_l1_table[i]);
}
@@ -563,6 +574,7 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
g_free(sn_l1_table);
sn_l1_table = NULL;
+ s->l1_size = sn->l1_size;
/*
* Update QCOW_OFLAG_COPIED in the active L1 table (it may have changed
* when we decreased the refcount of the old snapshot.
@@ -675,6 +687,7 @@ int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
sn_info->date_sec = sn->date_sec;
sn_info->date_nsec = sn->date_nsec;
sn_info->vm_clock_nsec = sn->vm_clock_nsec;
+ sn_info->disk_size = sn->disk_size;
}
*psn_tab = sn_tab;
return s->nb_snapshots;
diff --git a/block/qcow2.c b/block/qcow2.c
index 62febfc..58b53e1 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2501,22 +2501,33 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
return -EINVAL;
}
- /* cannot proceed if image has snapshots */
- if (s->nb_snapshots) {
- error_report("Can't resize an image which has snapshots");
+ bool v3_truncate = (s->qcow_version == 3);
+
+ /* cannot proceed if image has snapshots and qcow_version is not 3 */
+ if (!v3_truncate && s->nb_snapshots) {
+ error_report("Can't resize an image which has snapshots and "
+ "qcow_version is not 3");
return -ENOTSUP;
}
- /* shrinking is currently not supported */
- if (offset < bs->total_sectors * 512) {
- error_report("qcow2 doesn't support shrinking images yet");
+ /* shrinking is supported from version 3 */
+ if (!v3_truncate && offset < bs->total_sectors * 512) {
+ error_report("qcow2 doesn't support shrinking images yet while"
+ " qcow_version is not 3");
return -ENOTSUP;
}
new_l1_size = size_to_l1(s, offset);
- ret = qcow2_grow_l1_table(bs, new_l1_size, true);
- if (ret < 0) {
- return ret;
+ if (offset < bs->total_sectors * 512) {
+ ret = shrink_l1_table(bs, new_l1_size);
+ if (ret < 0) {
+ return ret;
+ }
+ } else {
+ ret = qcow2_grow_l1_table(bs, new_l1_size, true);
+ if (ret < 0) {
+ return ret;
+ }
}
/* write updated header.size */
diff --git a/block/qcow2.h b/block/qcow2.h
index a063a3c..dab9e48 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -534,6 +534,7 @@ int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order,
void *cb_opaque, Error **errp);
/* qcow2-cluster.c functions */
+int shrink_l1_table(BlockDriverState *bs, int64_t new_l1_size);
int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
bool exact_size);
int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
diff --git a/include/block/snapshot.h b/include/block/snapshot.h
index e5c0553..7279c12 100644
--- a/include/block/snapshot.h
+++ b/include/block/snapshot.h
@@ -44,6 +44,7 @@ typedef struct QEMUSnapshotInfo {
uint32_t date_sec; /* UTC date of the snapshot */
uint32_t date_nsec;
uint64_t vm_clock_nsec; /* VM clock relative to boot */
+ uint64_t disk_size;
} QEMUSnapshotInfo;
int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
--
1.7.1