diff mbox

[Qemu-block,v1,1/1] qcow2 resize with snapshots

Message ID 2521E138-9D98-43C2-8E75-56E491CBFED1@meituan.com (mailing list archive)
State New, archived
Headers show

Commit Message

zhangzhiming May 19, 2016, 8:56 a.m. UTC 
hi, missed some code.

zhangzhiming
zhangzhiming02@meituan.com

--



--

> On May 19, 2016, at 3:46 PM, zhangzhiming <zhangzhiming02@meituan.com> wrote:
> 
> hi, i wrote some code for 'qcow2 resize' with snapshot with v3 image and 'qcow2 goto’ too, 
> different size of snapshots are supported. 
> and i have tested the function and it  seems work well.
> there are some code copied from snapshot_delete_blkdev_internal, and qmp_block_resize, 
> it feels not very good.
> 
> please review it for me. thanks.
> 
> zhangzhiming
> zhangzhiming02@meituan.com
> 
> --
> 
> diff --git a/block.c b/block.c
> index 18a497f..047698a 100644
> --- a/block.c
> +++ b/block.c
> @@ -2632,6 +2632,24 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
> }
> 
> /**
> + *  goto a snapshot
> + */
> +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_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-snapshot.c b/block/qcow2-snapshot.c
> index 5f4a17e..9bc987f 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
> @@ -675,6 +668,7 @@ 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..6535f92 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -2501,15 +2501,17 @@ 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;
>     }
> 
> diff --git a/block/sheepdog.c b/block/sheepdog.c
> index 23fbace..bc12f7b 100644
> --- a/block/sheepdog.c
> +++ b/block/sheepdog.c
> @@ -2693,6 +2693,7 @@ static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
>             sn_tab[found].date_nsec = inode.snap_ctime & 0xffffffff;
>             sn_tab[found].vm_state_size = inode.vm_state_size;
>             sn_tab[found].vm_clock_nsec = inode.vm_clock_nsec;
> +            sn_tab[found].disk_size = inode.vdi_size;
> 
>             snprintf(sn_tab[found].id_str, sizeof(sn_tab[found].id_str),
>                      "%" PRIu32, inode.snap_id);
> diff --git a/blockdev.c b/blockdev.c
> index 1892b8e..36c66c1 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2961,6 +2961,120 @@ out:
>     aio_context_release(aio_context);
> }
> 
> +SnapshotInfo *qmp_blockdev_snapshot_goto_internal_sync(const char *device,
> +                             bool has_id,
> +                             const char *id,
> +                             bool has_name,
> +                             const char *name,
> +                             Error **errp)
> +{
> +    BlockDriverState *bs;
> +    BlockBackend *blk;
> +    AioContext *aio_context;
> +    QEMUSnapshotInfo sn;
> +    Error *local_err = NULL;
> +    SnapshotInfo *info = NULL;
> +    int ret;
> +
> +    blk = blk_by_name(device);
> +    if (!blk) {
> +        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> +                "Device '%s' not found", device);
> +        return NULL;
> +    }
> +    aio_context = blk_get_aio_context(blk);
> +    aio_context_acquire(aio_context);
> +
> +    if(!has_id){
> +        id = NULL;
> +    }
> +
> +    if(!has_name){
> +        name = NULL;
> +    }
> +
> +    if(!id && !name){
> +        error_setg(errp, "Name or id must be provided");
> +        goto out_aio_context;
> +    }
> +
> +    if(!blk_is_available(blk)){
> +        error_setg(errp, "Device '%s' has no medium", device);
> +        goto out_aio_context;
> +    }
> +
> +    bs = blk_bs(blk);
> +
> +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_APPLY, errp)){
> +        goto out_aio_context;
> +    }
> +
> +    ret = bdrv_snapshot_find_by_id_and_name(bs, id, name, &sn, &local_err);
> +    if(local_err){
> +        error_propagate(errp, local_err);
> +        goto out_aio_context;
> +    }
> +    if(!ret){
> +        error_setg(errp,
> +                   "Snapshot with id '%s' and name '%s' does not exist on "
> +                   "device '%s'",
> +                   STR_OR_NULL(id), STR_OR_NULL(name), device);
> +        goto out_aio_context;
> +    }
> +    if(!sn.disk_size){
> +        error_setg(errp,
> +                   "Snapshot with id '%s' and name '%s' does not has a disk size "
> +                   "device '%s'",
> +                   STR_OR_NULL(id), STR_OR_NULL(name), device);
> +        goto out_aio_context;
> +    }
> +
> +    /* complete all in-flight operations before resizing the device */
> +    bdrv_drain_all();
> +
> +    ret = bdrv_apply_snapshot(bs, sn.id_str, sn.disk_size);
> +    switch (ret) {
> +    case 0:
> +        break;
> +    case -ENOMEDIUM:
> +        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
> +        break;
> +    case -ENOTSUP:
> +        error_setg(errp, QERR_UNSUPPORTED);
> +        break;
> +    case -EACCES:
> +        error_setg(errp, "Device '%s' is read only", device);
> +        break;
> +    case -EBUSY:
> +        error_setg(errp, QERR_DEVICE_IN_USE, device);
> +        break;
> +    default:
> +        error_setg_errno(errp, -ret, "Could not resize");
> +        break;
> +    }
> +
> +    if(ret < 0){
> +        goto out_aio_context;
> +    }
> +
> +    aio_context_release(aio_context);
> +
> +    info = g_new0(SnapshotInfo, 1);
> +    info->id = g_strdup(sn.id_str);
> +    info->name = g_strdup(sn.name);
> +    info->date_nsec = sn.date_nsec;
> +    info->date_sec = sn.date_sec;
> +    info->vm_state_size = sn.vm_state_size;
> +    info->vm_clock_nsec = sn.vm_clock_nsec % 1000000000;
> +    info->vm_clock_sec = sn.vm_clock_nsec / 1000000000;
> +
> +    return info;
> +
> +out_aio_context:
> +    aio_context_release(aio_context);
> +    return NULL;
> +}
> +
> static void block_job_cb(void *opaque, int ret)
> {
>     /* Note that this function may be executed from another AioContext besides
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 4f4f60a..5848a57 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1159,6 +1159,24 @@ Delete an internal snapshot on device if it support
> ETEXI
> 
>     {
> +        .name       = "snapshot_goto_blkdev_internal",
> +        .args_type  = "device:B,name:s,id:s?",
> +        .params     = "device name [id]",
> +        .help       = "apply an internal snapshot of device.\n\t\t\t"
> +                      "If id is specified, qemu will try apply\n\t\t\t"
> +                      "the snapshot matching both id and name.\n\t\t\t"
> +                      "The format of the image used by device must\n\t\t\t"
> +                      "support it, such as qcow2.\n\t\t\t",
> +        .mhandler.cmd = hmp_snapshot_goto_blkdev_internal,
> +    },
> +
> +STEXI
> +@item snapshot_goto_blkdev_internal
> +@findex snapshot_goto_blkdev_internal
> +Apply an internal snapshot on device if it support
> +ETEXI
> +
> +    {
>         .name       = "drive_mirror",
>         .args_type  = "reuse:-n,full:-f,device:B,target:s,format:s?",
>         .params     = "[-n] [-f] device target [format]",
> diff --git a/hmp.c b/hmp.c
> index d510236..3f1d146 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -1057,6 +1057,8 @@ void hmp_block_resize(Monitor *mon, const QDict *qdict)
>     hmp_handle_error(mon, &err);
> }
> 
> +
> +
> void hmp_drive_mirror(Monitor *mon, const QDict *qdict)
> {
>     const char *device = qdict_get_str(qdict, "device");
> @@ -1163,6 +1165,17 @@ void hmp_snapshot_delete_blkdev_internal(Monitor *mon, const QDict *qdict)
>     hmp_handle_error(mon, &err);
> }
> 
> +void hmp_snapshot_goto_blkdev_internal(Monitor *mon, const QDict *qdict)
> +{
> +    const char *device = qdict_get_str(qdict, "device");
> +    const char *name = qdict_get_str(qdict, "name");
> +    const char *id = qdict_get_try_str(qdict, "id");
> +    Error *err = NULL;
> +
> +    qmp_blockdev_snapshot_goto_internal_sync(device, !!id, id, true, name, &err);
> +    hmp_handle_error(mon, &err);
> +}
> +
> void hmp_migrate_cancel(Monitor *mon, const QDict *qdict)
> {
>     qmp_migrate_cancel(NULL);
> diff --git a/hmp.h b/hmp.h
> index 093d65f..b1ad2f5 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -59,6 +59,7 @@ void hmp_block_resize(Monitor *mon, const QDict *qdict);
> void hmp_snapshot_blkdev(Monitor *mon, const QDict *qdict);
> void hmp_snapshot_blkdev_internal(Monitor *mon, const QDict *qdict);
> void hmp_snapshot_delete_blkdev_internal(Monitor *mon, const QDict *qdict);
> +void hmp_snapshot_goto_blkdev_internal(Monitor *mon, const QDict *qdict);
> void hmp_drive_mirror(Monitor *mon, const QDict *qdict);
> void hmp_drive_backup(Monitor *mon, const QDict *qdict);
> void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
> diff --git a/include/block/block.h b/include/block/block.h
> index b210832..393ca6b 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -173,6 +173,7 @@ typedef enum BlockOpType {
>     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
>     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
>     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
> +    BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_APPLY,
>     BLOCK_OP_TYPE_MIRROR_SOURCE,
>     BLOCK_OP_TYPE_MIRROR_TARGET,
>     BLOCK_OP_TYPE_RESIZE,
> @@ -266,6 +267,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
> int bdrv_get_backing_file_depth(BlockDriverState *bs);
> void bdrv_refresh_filename(BlockDriverState *bs);
> int bdrv_truncate(BlockDriverState *bs, int64_t offset);
> +int bdrv_apply_snapshot(BlockDriverState *bs, const char *snapshot_id, uint64_t snapshot_size);
> int64_t bdrv_nb_sectors(BlockDriverState *bs);
> int64_t bdrv_getlength(BlockDriverState *bs);
> int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
> 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,
> diff --git a/pixman b/pixman
> index 87eea99..7c6066b 160000
> --- a/pixman
> +++ b/pixman
> @@ -1 +1 @@
> -Subproject commit 87eea99e443b389c978cf37efc52788bf03a0ee0
> +Subproject commit 7c6066b700c7cdd4aeb8be426b14b3a5f0de4b6c
> 
> --
> 
>
diff mbox

Patch

diff --git a/block.c b/block.c
index 047698a..ff83134 100644
--- a/block.c
+++ b/block.c
@@ -2641,7 +2641,7 @@  int bdrv_apply_snapshot(BlockDriverState *bs, const char *snapshot_id, uint64_t
         return ret;
     }
 
-    ret = refresh_total_sectors(bs, snapshot_size);
+    ret = refresh_total_sectors(bs, snapshot_size >> BDRV_SECTOR_BITS);
     bdrv_dirty_bitmap_truncate(bs);
     if (bs->blk) {
         blk_dev_resize_cb(bs->blk);
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 9bc987f..d872cf2 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -528,6 +528,14 @@  int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
         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;
+    }
+
     /*
      * Decrease refcount of clusters of current L1 table.
      *