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Re: [Qemu-devel] [PATCH v3 6/6] vmdk: Update metadata for multiple clust
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v3 6/6] vmdk: Update metadata for multiple clusters |
Date: |
Fri, 21 Apr 2017 16:15:04 +0800 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
On Sat, 04/01 20:14, Ashijeet Acharya wrote:
> Include a next pointer in VmdkMetaData struct to point to the previous
> allocated L2 table. Modify vmdk_L2update to start updating metadata for
> allocation of multiple clusters at once.
>
> Signed-off-by: Ashijeet Acharya <address@hidden>
This is the metadata part of the coalesed allocation. I think patch 3 is
functionally incomplete without these changes, and is perhaps broken because
metadata is not handled correctly.
Such an "intermediate functional regression" is not good in a series, which we
need to avoid.
> ---
> block/vmdk.c | 136
> ++++++++++++++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 111 insertions(+), 25 deletions(-)
>
> diff --git a/block/vmdk.c b/block/vmdk.c
> index 9456ddd..c7675db 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -137,6 +137,8 @@ typedef struct VmdkMetaData {
> int valid;
> uint32_t *l2_cache_entry;
> uint32_t nb_clusters;
> + uint32_t offset;
> + struct VmdkMetaData *next;
> } VmdkMetaData;
>
> typedef struct VmdkGrainMarker {
> @@ -263,6 +265,12 @@ static inline uint64_t size_to_clusters(VmdkExtent
> *extent, uint64_t size)
> return (DIV_ROUND_UP(size + round_off_size, BDRV_SECTOR_SIZE * 128) - 1);
> }
>
> +static inline int64_t vmdk_align_offset(int64_t offset, int n)
> +{
> + offset = (offset + n - 1) & ~(n - 1);
> + return offset;
> +}
> +
> static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
> {
> char *desc;
> @@ -1037,29 +1045,88 @@ static void vmdk_refresh_limits(BlockDriverState *bs,
> Error **errp)
> }
> }
>
> -static int vmdk_L2update(VmdkExtent *extent, VmdkMetaData *m_data,
> - uint32_t offset)
> +static int vmdk_alloc_cluster_link_l2(VmdkExtent *extent,
> + VmdkMetaData *m_data, bool zeroed)
> {
> - offset = cpu_to_le32(offset);
> + int i;
> + uint32_t offset, temp_offset;
> + int *l2_table_array;
> + int l2_array_size;
> +
> + if (zeroed) {
> + temp_offset = VMDK_GTE_ZEROED;
> + } else {
> + temp_offset = m_data->offset;
> + }
> +
> + temp_offset = cpu_to_le32(temp_offset);
> +
> + l2_array_size = sizeof(uint32_t) * m_data->nb_clusters;
> + l2_table_array = qemu_try_blockalign(extent->file->bs,
> + vmdk_align_offset(l2_array_size, 512));
Indentation is off.
Use QEMU_ALIGN_UP, instead of vmdk_align_offset.
512 is a magic number, use BDRV_SECTOR_SIZE.
> + if (l2_table_array == NULL) {
> + return VMDK_ERROR;
> + }
> + memset(l2_table_array, 0, vmdk_align_offset(l2_array_size, 512));
> +
> /* update L2 table */
> + offset = temp_offset;
> + for (i = 0; i < m_data->nb_clusters; i++) {
> + l2_table_array[i] = offset;
> + if (!zeroed) {
> + offset += 128;
Something is going wrong here with endianness on BE host, I believe.
> + }
> + }
> +
> if (bdrv_pwrite_sync(extent->file,
> - ((int64_t)m_data->l2_offset * 512)
> - + (m_data->l2_index * sizeof(offset)),
> - &offset, sizeof(offset)) < 0) {
> + ((int64_t)m_data->l2_offset * 512)
> + + ((m_data->l2_index) * sizeof(offset)),
> + l2_table_array, l2_array_size) < 0) {
You can fix the indentation while changing these lines. If not, don't change it,
or at least don't make it uglier.
> return VMDK_ERROR;
> }
> +
> /* update backup L2 table */
> if (extent->l1_backup_table_offset != 0) {
> m_data->l2_offset = extent->l1_backup_table[m_data->l1_index];
> if (bdrv_pwrite_sync(extent->file,
> ((int64_t)m_data->l2_offset * 512)
> - + (m_data->l2_index * sizeof(offset)),
> - &offset, sizeof(offset)) < 0) {
> + + ((m_data->l2_index) * sizeof(offset)),
> + l2_table_array, l2_array_size) < 0) {
Same here.
> return VMDK_ERROR;
> }
> }
> +
> + offset = temp_offset;
> if (m_data->l2_cache_entry) {
> - *m_data->l2_cache_entry = offset;
> + for (i = 0; i < m_data->nb_clusters; i++) {
> + *m_data->l2_cache_entry = offset;
> + m_data->l2_cache_entry++;
> +
> + if (!zeroed) {
> + offset += 128;
> + }
> + }
> + }
> +
> + qemu_vfree(l2_table_array);
> + return VMDK_OK;
> +}
> +
> +static int vmdk_L2update(VmdkExtent *extent, VmdkMetaData *m_data,
> + bool zeroed)
> +{
> + int ret;
> +
> + while (m_data->next != NULL) {
> + VmdkMetaData *next;
> +
> + ret = vmdk_alloc_cluster_link_l2(extent, m_data, zeroed);
> + if (ret < 0) {
> + return ret;
> + }
> +
> + next = m_data->next;
> + m_data = next;
Why not simply "m_data = m_data->next" and drop "next" variable?
> }
>
> return VMDK_OK;
> @@ -1271,7 +1338,7 @@ exit:
> */
> static int handle_alloc(BlockDriverState *bs, VmdkExtent *extent,
> uint64_t offset, uint64_t *cluster_offset,
> - int64_t *bytes, VmdkMetaData *m_data,
> + int64_t *bytes, VmdkMetaData **m_data,
> bool allocate, uint32_t *total_alloc_clusters)
> {
> int l1_index, l2_offset, l2_index;
> @@ -1280,6 +1347,7 @@ static int handle_alloc(BlockDriverState *bs,
> VmdkExtent *extent,
> uint32_t nb_clusters;
> bool zeroed = false;
> uint64_t skip_start_bytes, skip_end_bytes;
> + VmdkMetaData *old_m_data;
> int ret;
>
> ret = get_cluster_table(extent, offset, &l1_index, &l2_offset,
> @@ -1330,13 +1398,21 @@ static int handle_alloc(BlockDriverState *bs,
> VmdkExtent *extent,
> if (ret < 0) {
> return ret;
> }
> - if (m_data) {
> - m_data->valid = 1;
> - m_data->l1_index = l1_index;
> - m_data->l2_index = l2_index;
> - m_data->l2_offset = l2_offset;
> - m_data->l2_cache_entry = &l2_table[l2_index];
> - m_data->nb_clusters = nb_clusters;
> +
> + if (*m_data) {
> + old_m_data = *m_data;
> + *m_data = g_malloc0(sizeof(**m_data));
> +
> + **m_data = (VmdkMetaData) {
> + .valid = 1,
> + .l1_index = l1_index,
> + .l2_index = l2_index,
> + .l2_offset = l2_offset,
> + .l2_cache_entry = &l2_table[l2_index],
> + .nb_clusters = nb_clusters,
> + .offset = cluster_sector,
> + .next = old_m_data,
> + };
I think if the new m_data can be merged into the old, there is no need to
allocate a new one.
> }
> }
> *cluster_offset = cluster_sector << BDRV_SECTOR_BITS;
> @@ -1365,7 +1441,7 @@ static int handle_alloc(BlockDriverState *bs,
> VmdkExtent *extent,
> */
> static int vmdk_alloc_cluster_offset(BlockDriverState *bs,
> VmdkExtent *extent,
> - VmdkMetaData *m_data, uint64_t offset,
> + VmdkMetaData **m_data, uint64_t offset,
> bool allocate, uint64_t *cluster_offset,
> int64_t bytes,
> uint32_t *total_alloc_clusters)
> @@ -1385,8 +1461,8 @@ static int vmdk_alloc_cluster_offset(BlockDriverState
> *bs,
> new_cluster_offset = 0;
> *cluster_offset = 0;
> n_bytes = 0;
> - if (m_data) {
> - m_data->valid = 0;
> + if (*m_data) {
> + (*m_data)->valid = 0;
> }
>
> /* due to L2 table margins all bytes may not get allocated at once */
> @@ -1768,9 +1844,11 @@ static int vmdk_pwritev(BlockDriverState *bs, uint64_t
> offset,
> uint64_t cluster_offset;
> uint64_t bytes_done = 0;
> uint64_t extent_size;
> - VmdkMetaData m_data;
> + VmdkMetaData *m_data;
> uint32_t total_alloc_clusters = 0;
>
> + m_data = g_malloc0(sizeof(*m_data));
> +
> if (DIV_ROUND_UP(offset, BDRV_SECTOR_SIZE) > bs->total_sectors) {
> error_report("Wrong offset: offset=0x%" PRIx64
> " total_sectors=0x%" PRIx64,
> @@ -1779,6 +1857,7 @@ static int vmdk_pwritev(BlockDriverState *bs, uint64_t
> offset,
> }
>
> while (bytes > 0) {
> + m_data->next = NULL;
> extent = find_extent(s, offset >> BDRV_SECTOR_BITS, extent);
> if (!extent) {
> return -EIO;
> @@ -1825,7 +1904,7 @@ static int vmdk_pwritev(BlockDriverState *bs, uint64_t
> offset,
> total_alloc_clusters;
> if (!zero_dry_run) {
> /* update L2 tables */
> - if (vmdk_L2update(extent, &m_data, VMDK_GTE_ZEROED)
> + if (vmdk_L2update(extent, m_data, zeroed)
> != VMDK_OK) {
> return -EIO;
> }
> @@ -1839,10 +1918,9 @@ static int vmdk_pwritev(BlockDriverState *bs, uint64_t
> offset,
> if (ret) {
> return ret;
> }
> - if (m_data.valid) {
> + if (m_data->valid) {
> /* update L2 tables */
> - if (vmdk_L2update(extent, &m_data,
> - cluster_offset >> BDRV_SECTOR_BITS)
> + if (vmdk_L2update(extent, m_data, zeroed)
> != VMDK_OK) {
> return -EIO;
> }
> @@ -1852,6 +1930,13 @@ static int vmdk_pwritev(BlockDriverState *bs, uint64_t
> offset,
> offset += n_bytes;
> bytes_done += n_bytes;
>
> + while (m_data->next != NULL) {
> + VmdkMetaData *next;
> + next = m_data->next;
> + g_free(m_data);
> + m_data = next;
> + }
> +
> /* update CID on the first write every time the virtual disk is
> * opened */
> if (!s->cid_updated) {
> @@ -1862,6 +1947,7 @@ static int vmdk_pwritev(BlockDriverState *bs, uint64_t
> offset,
> s->cid_updated = true;
> }
> }
> + g_free(m_data);
This is weird, you free all but the last m_data with a while loop, a few lines
above, and this one with a separate g_free().
Please use one loop:
for (p = m_data; p; p = next) {
next = p->next;
g_free(p);
}
> return 0;
> }
>
> --
> 2.6.2
>
- Re: [Qemu-devel] [PATCH v3 3/6] vmdk: New functions to assist allocating multiple clusters, (continued)
[Qemu-devel] [PATCH v3 4/6] vmdk: Rename get_cluster_offset() to vmdk_get_cluster_offset(), Ashijeet Acharya, 2017/04/01
[Qemu-devel] [PATCH v3 5/6] vmdk: Set maximum bytes allocated in one cycle, Ashijeet Acharya, 2017/04/01
[Qemu-devel] [PATCH v3 6/6] vmdk: Update metadata for multiple clusters, Ashijeet Acharya, 2017/04/01
- Re: [Qemu-devel] [PATCH v3 6/6] vmdk: Update metadata for multiple clusters,
Fam Zheng <=