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Re: [Qemu-devel] [Qemu-block] [PATCH] qcow2 resize with snapshot
|
From: |
zhangzhiming |
|
Subject: |
Re: [Qemu-devel] [Qemu-block] [PATCH] qcow2 resize with snapshot |
|
Date: |
Thu, 23 Jun 2016 22:34:48 +0800 |
hi, please help to review my code. i have checked it for serval times.
it is short and very easy too read. and i will be very grateful to you for
taking a very little time
to read it. thanks very much!
zhangzhiming
address@hidden <mailto:address@hidden>
Signed-off-by: zhangzhiming <address@hidden <mailto:address@hidden>>
---
block.c | 19 +++++++++++++++++++
block/qcow2-cluster.c | 29 +++++++++++++++++++++++++++++
block/qcow2-snapshot.c | 37 +++++++++++++++++++++++++------------
block/qcow2.c | 29 ++++++++++++++++++++---------
block/qcow2.h | 1 +
include/block/snapshot.h | 1 +
6 files changed, 95 insertions(+), 21 deletions(-)
diff --git a/block.c b/block.c
index f54bc25..0de7b2d 100644
--- a/block.c
+++ b/block.c
@@ -2586,6 +2586,25 @@ 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 b04bfaf..ebadddf 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -32,6 +32,35 @@
#include "qemu/bswap.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 242fb21..6dd6769 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -478,13 +478,6 @@ 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
@@ -506,8 +499,8 @@ 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);
- if (cur_l1_bytes && sn_l1_table == NULL) {
+ sn_l1_table = g_try_malloc0(sn_l1_bytes);
+ if (sn_l1_bytes && sn_l1_table == NULL) {
ret = -ENOMEM;
goto fail;
}
@@ -525,17 +518,34 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char
*snapshot_id)
}
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
- s->l1_table_offset, cur_l1_bytes);
+ s->l1_table_offset, sn_l1_bytes);
if (ret < 0) {
goto fail;
}
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.
*
@@ -553,7 +563,8 @@ 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]);
}
@@ -564,6 +575,7 @@ 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.
@@ -676,6 +688,7 @@ 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 6f5fb81..612a534 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2495,22 +2495,33 @@ 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 7db9795..8efa735 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
> On Jun 7, 2016, at 4:25 PM, zhangzhiming <address@hidden> wrote:
>
> hi, need for someone's review of my code. no one does it for nearly one week.
> thanks!
>
> zhangzhiming
> address@hidden <mailto:address@hidden>
>
>
>
>> On Jun 1, 2016, at 6:24 PM, zhangzhiming <address@hidden
>> <mailto:address@hidden>> wrote:
>>
>> hi, here are all changes of my code. thanks for the review!
>>
>> zhangzhiming
>> address@hidden <mailto:address@hidden>
>>
>> Signed-off-by: zhangzhiming <address@hidden <mailto:address@hidden>>
>> ---
>> 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
>>
>>
>>> On Jun 1, 2016, at 12:15 PM, zhangzhiming <address@hidden
>>> <mailto:address@hidden>> wrote:
>>>
>>> hi, thanks for the review and the format of code changed.
>>> have a good day!
>>>
>>> zhangzhiming
>>> address@hidden <mailto:address@hidden>
>>>
>>> Signed-off-by: zhangzhiming <address@hidden <http://meituan.com/>>
>>> ---
>>> block.c | 4 ++--
>>> block/qcow2-cluster.c | 4 ++--
>>> block/qcow2-snapshot.c | 5 ++---
>>> block/qcow2.c | 4 ++--
>>> 4 files changed, 8 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/block.c b/block.c
>>> index 729f820..b6f2004 100644
>>> --- a/block.c
>>> +++ b/block.c
>>> @@ -2643,9 +2643,9 @@ int bdrv_apply_snapshot(BlockDriverState *bs, const
>>> char *snapshot_id,
>>> if (ret < 0) {
>>> return ret;
>>> }
>>> - bdrv_dirty_bitmap_truncate(bs); /* void return */
>>> + bdrv_dirty_bitmap_truncate(bs);
>>> if (bs->blk) {
>>> - blk_dev_resize_cb(bs->blk); /* void return too */
>>> + blk_dev_resize_cb(bs->blk);
>>> }
>>> return ret;
>>> }
>>> diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
>>> index e4c5c05..f921fd8 100644
>>> --- a/block/qcow2-cluster.c
>>> +++ b/block/qcow2-cluster.c
>>> @@ -37,14 +37,14 @@ int shrink_l1_table(BlockDriverState *bs, int64_t
>>> new_l1_size)
>>> 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);
>>> + 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);
>>> + s->l1_size, -1);
>>> if (ret < 0) {
>>> return ret;
>>> }
>>> diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
>>> index 9c77096..1ed0e18 100644
>>> --- a/block/qcow2-snapshot.c
>>> +++ b/block/qcow2-snapshot.c
>>> @@ -562,12 +562,11 @@ 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.
>>> */
>>> - memset(s->l1_table, 0, s->l1_size*sizeof(uint64_t));
>>> - for(i = 0;i < sn->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]);
>>> }
>>>
>>> -
>>> if (ret < 0) {
>>> goto fail;
>>> }
>>> diff --git a/block/qcow2.c b/block/qcow2.c
>>> index 70ec890..58b53e1 100644
>>> --- a/block/qcow2.c
>>> +++ b/block/qcow2.c
>>> @@ -2503,14 +2503,14 @@ static int qcow2_truncate(BlockDriverState *bs,
>>> int64_t offset)
>>>
>>> bool v3_truncate = (s->qcow_version == 3);
>>>
>>> - /* cannot proceed if image has snapshots and qcow_version is not 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 supported from version 3*/
>>> + /* 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");
>>> --
>>> 1.7.1
>>>
>>>
>>>> On Jun 1, 2016, at 12:50 AM, Eric Blake <address@hidden
>>>> <mailto:address@hidden>> wrote:
>>>>
>>>> On 05/27/2016 02:14 AM, zhangzhiming wrote:
>>>>> Hi, i modified my code for qcow2 resize, and delete some code related to
>>>>> qemu monitor.
>>>>>
>>>>> and thanks for the review.
>>>>>
>>>>> zhangzhiming
>>>>> address@hidden <mailto:address@hidden> <mailto:address@hidden
>>>>> <mailto:address@hidden>>
>>>>
>>>> Still missing a Signed-off-by designation, so it can't be applied as-is.
>>>>
>>>>>
>>>>> ---
>>>>> block.c | 19 +++++++++++++++++++
>>>>> block/qcow2-cluster.c | 29 +++++++++++++++++++++++++++++
>>>>> block/qcow2-snapshot.c | 34 ++++++++++++++++++++++++----------
>>>>> block/qcow2.c | 29 ++++++++++++++++++++---------
>>>>> block/qcow2.h | 1 +
>>>>> include/block/snapshot.h | 1 +
>>>>> 6 files changed, 94 insertions(+), 19 deletions(-)
>>>>>
>>>>> diff --git a/block.c b/block.c
>>>>> index 18a497f..729f820 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); /* void return */
>>>>> + if (bs->blk) {
>>>>> + blk_dev_resize_cb(bs->blk); /* void return too */
>>>>
>>>> The comments don't add anything here.
>>>>
>>>>> + }
>>>>> + 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..e4c5c05 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);
>>>>
>>>> Indentation is off.
>>>>
>>>>> + 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);
>>>>
>>>> and again.
>>>>
>>>>> + if (ret < 0) {
>>>>> + return ret;
>>>>> + }
>>>>> + s->l1_size = new_l1_size;
>>>>> +
>>>>
>>>>> +++ b/block/qcow2-snapshot.c
>>>>
>>>>> @@ -552,10 +562,12 @@ 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++) {
>>>>
>>>> As long as you are touching this, use the preferred spacing:
>>>>
>>>> for (i = 0; i < sn->l1_size; i++) {
>>>>
>>>>> s->l1_table[i] = be64_to_cpu(sn_l1_table[i]);
>>>>> }
>>>>>
>>>>> +
>>>>> if (ret < 0) {
>>>>
>>>> Why the added blank line?
>>>>
>>>>
>>>>> +++ 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*/
>>>>
>>>> Space before */
>>>>
>>>>> + 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*/
>>>>
>>>> and again
>>>>
>>>>> + 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;
>>>>> }
>>>>
>>>>
>>>> --
>>>> Eric Blake eblake redhat com +1-919-301-3266
>>>> Libvirt virtualization library http://libvirt.org <http://libvirt.org/>
>>>>
>>>
>>
>