[Qemu-devel] [PATCH 01/12] VMDK: Introduced VmdkExtent

[Fam Zheng]

Added VmdkExtent array to hold image extent information, with the
exsiting functionalities fit into this structure.

Signed-off-by: Fam Zheng <address@hidden>
---
 block/vmdk.c |  301 ++++++++++++++++++++++++++++++++++++++--------------------
 1 files changed, 200 insertions(+), 101 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 8fc9d67..9442794 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -60,7 +60,10 @@ typedef struct {

 #define L2_CACHE_SIZE 16

-typedef struct BDRVVmdkState {
+typedef struct VmdkExtent {
+    BlockDriverState *file;
+    bool flat;
+    int64_t sectors;
     int64_t l1_table_offset;
     int64_t l1_backup_table_offset;
     uint32_t *l1_table;
@@ -75,6 +78,11 @@ typedef struct BDRVVmdkState {

     unsigned int cluster_sectors;
     uint32_t parent_cid;
+} VmdkExtent;
+
+typedef struct BDRVVmdkState {
+    int num_extents;
+    VmdkExtent *extents;
 } BDRVVmdkState;

 typedef struct VmdkMetaData {
@@ -154,16 +162,15 @@ static int vmdk_write_cid(BlockDriverState *bs,
uint32_t cid)
     return 0;
 }

-static int vmdk_is_cid_valid(BlockDriverState *bs)
+static int vmdk_is_cid_valid(BlockDriverState *bs, VmdkExtent *extent)
 {
 #ifdef CHECK_CID
-    BDRVVmdkState *s = bs->opaque;
     BlockDriverState *p_bs = bs->backing_hd;
     uint32_t cur_pcid;

     if (p_bs) {
         cur_pcid = vmdk_read_cid(p_bs,0);
-        if (s->parent_cid != cur_pcid)
+        if (extent->parent_cid != cur_pcid)
             // CID not valid
             return 0;
     }
@@ -363,6 +370,7 @@ static int vmdk_open(BlockDriverState *bs, int flags)
     BDRVVmdkState *s = bs->opaque;
     uint32_t magic;
     int l1_size, i;
+    VmdkExtent *extent = NULL;

     if (bdrv_pread(bs->file, 0, &magic, sizeof(magic)) != sizeof(magic))
         goto fail;
@@ -370,94 +378,126 @@ static int vmdk_open(BlockDriverState *bs, int flags)
     magic = be32_to_cpu(magic);
     if (magic == VMDK3_MAGIC) {
         VMDK3Header header;
-
-        if (bdrv_pread(bs->file, sizeof(magic), &header,
sizeof(header)) != sizeof(header))
+        s->extents = qemu_mallocz(sizeof(VmdkExtent));
+        s->num_extents = 1;
+        if (bdrv_pread(bs->file, sizeof(magic), &header, sizeof(header))
+            != sizeof(header))
             goto fail;
-        s->cluster_sectors = le32_to_cpu(header.granularity);
-        s->l2_size = 1 << 9;
-        s->l1_size = 1 << 6;
-        bs->total_sectors = le32_to_cpu(header.disk_sectors);
-        s->l1_table_offset = le32_to_cpu(header.l1dir_offset) << 9;
-        s->l1_backup_table_offset = 0;
-        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
+        extent = s->extents;
+        extent->flat = false;
+        extent->file = bs->file;
+        extent->cluster_sectors = le32_to_cpu(header.granularity);
+        extent->l2_size = 1 << 9;
+        extent->l1_size = 1 << 6;
+        extent->sectors = le32_to_cpu(header.disk_sectors);
+        extent->l1_table_offset = le32_to_cpu(header.l1dir_offset) << 9;
+        extent->l1_backup_table_offset = 0;
+        extent->l1_entry_sectors = extent->l2_size * extent->cluster_sectors;
     } else if (magic == VMDK4_MAGIC) {
         VMDK4Header header;
-
-        if (bdrv_pread(bs->file, sizeof(magic), &header,
sizeof(header)) != sizeof(header))
+        s->extents = qemu_mallocz(sizeof(VmdkExtent));
+        s->num_extents = 1;
+        if (bdrv_pread(bs->file, sizeof(magic), &header, sizeof(header))
+            != sizeof(header))
             goto fail;
-        bs->total_sectors = le64_to_cpu(header.capacity);
-        s->cluster_sectors = le64_to_cpu(header.granularity);
-        s->l2_size = le32_to_cpu(header.num_gtes_per_gte);
-        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
-        if (s->l1_entry_sectors <= 0)
+        extent = s->extents;
+        extent->file = bs->file;
+        extent->sectors = le64_to_cpu(header.capacity);
+        extent->cluster_sectors = le64_to_cpu(header.granularity);
+        extent->l2_size = le32_to_cpu(header.num_gtes_per_gte);
+        extent->l1_entry_sectors = extent->l2_size * extent->cluster_sectors;
+        if (extent->l1_entry_sectors <= 0)
             goto fail;
-        s->l1_size = (bs->total_sectors + s->l1_entry_sectors - 1)
-            / s->l1_entry_sectors;
-        s->l1_table_offset = le64_to_cpu(header.rgd_offset) << 9;
-        s->l1_backup_table_offset = le64_to_cpu(header.gd_offset) << 9;
+        extent->l1_size = (extent->sectors + extent->l1_entry_sectors - 1)
+            / extent->l1_entry_sectors;
+        extent->l1_table_offset = le64_to_cpu(header.rgd_offset) << 9;
+        extent->l1_backup_table_offset = le64_to_cpu(header.gd_offset) << 9;

         // try to open parent images, if exist
         if (vmdk_parent_open(bs) != 0)
             goto fail;
         // write the CID once after the image creation
-        s->parent_cid = vmdk_read_cid(bs,1);
+        extent->parent_cid = vmdk_read_cid(bs,1);
     } else {
         goto fail;
     }

+    /* sum up the total sectors */
+    bs->total_sectors = 0;
+    for (i = 0; i < s->num_extents; i++)
+    {
+        bs->total_sectors += s->extents[i].sectors;
+    }
+
     /* read the L1 table */
-    l1_size = s->l1_size * sizeof(uint32_t);
-    s->l1_table = qemu_malloc(l1_size);
-    if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
l1_size) != l1_size)
+    l1_size = extent->l1_size * sizeof(uint32_t);
+    extent->l1_table = qemu_malloc(l1_size);
+    if (bdrv_pread(bs->file,
+            extent->l1_table_offset,
+            extent->l1_table,
+            l1_size)
+        != l1_size)
         goto fail;
-    for(i = 0; i < s->l1_size; i++) {
-        le32_to_cpus(&s->l1_table[i]);
+    for(i = 0; i < extent->l1_size; i++) {
+        le32_to_cpus(&extent->l1_table[i]);
     }

-    if (s->l1_backup_table_offset) {
-        s->l1_backup_table = qemu_malloc(l1_size);
-        if (bdrv_pread(bs->file, s->l1_backup_table_offset,
s->l1_backup_table, l1_size) != l1_size)
+    if (extent->l1_backup_table_offset) {
+        extent->l1_backup_table = qemu_malloc(l1_size);
+        if (bdrv_pread(bs->file,
+                extent->l1_backup_table_offset,
+                extent->l1_backup_table,
+                l1_size)
+            != l1_size)
             goto fail;
-        for(i = 0; i < s->l1_size; i++) {
-            le32_to_cpus(&s->l1_backup_table[i]);
+        for(i = 0; i < extent->l1_size; i++) {
+            le32_to_cpus(&extent->l1_backup_table[i]);
         }
     }

-    s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));
+    extent->l2_cache =
+        qemu_malloc(extent->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));
     return 0;
  fail:
-    qemu_free(s->l1_backup_table);
-    qemu_free(s->l1_table);
-    qemu_free(s->l2_cache);
+    if(s->extents) {
+        qemu_free(s->extents[0].l1_backup_table);
+        qemu_free(s->extents[0].l1_table);
+        qemu_free(s->extents[0].l2_cache);
+    }
     return -1;
 }

-static uint64_t get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
-                                   uint64_t offset, int allocate);
-
-static int get_whole_cluster(BlockDriverState *bs, uint64_t cluster_offset,
-                             uint64_t offset, int allocate)
+static uint64_t get_cluster_offset(BlockDriverState *bs,
+                    VmdkExtent *extent,
+                    VmdkMetaData *m_data,
+                    uint64_t offset,
+                    int allocate);
+
+static int get_whole_cluster(BlockDriverState *bs,
+                VmdkExtent *extent,
+                uint64_t cluster_offset,
+                uint64_t offset,
+                bool allocate)
 {
-    BDRVVmdkState *s = bs->opaque;
-    uint8_t  whole_grain[s->cluster_sectors*512];        // 128
sectors * 512 bytes each = grain size 64KB
+    uint8_t  whole_grain[extent->cluster_sectors*512];        // 128
sectors * 512 bytes each = grain size 64KB

     // we will be here if it's first write on non-exist grain(cluster).
     // try to read from parent image, if exist
     if (bs->backing_hd) {
         int ret;

-        if (!vmdk_is_cid_valid(bs))
+        if (!vmdk_is_cid_valid(bs, extent))
             return -1;

         ret = bdrv_read(bs->backing_hd, offset >> 9, whole_grain,
-            s->cluster_sectors);
+                extent->cluster_sectors);
         if (ret < 0) {
             return -1;
         }

         //Write grain only into the active image
-        ret = bdrv_write(bs->file, cluster_offset, whole_grain,
-            s->cluster_sectors);
+        ret = bdrv_write(extent->file, cluster_offset, whole_grain,
+                extent->cluster_sectors);
         if (ret < 0) {
             return -1;
         }
@@ -465,29 +505,36 @@ static int get_whole_cluster(BlockDriverState
*bs, uint64_t cluster_offset,
     return 0;
 }

-static int vmdk_L2update(BlockDriverState *bs, VmdkMetaData *m_data)
+static int vmdk_L2update(VmdkExtent *extent, VmdkMetaData *m_data)
 {
-    BDRVVmdkState *s = bs->opaque;
-
     /* update L2 table */
-    if (bdrv_pwrite_sync(bs->file, ((int64_t)m_data->l2_offset * 512)
+ (m_data->l2_index * sizeof(m_data->offset)),
-                    &(m_data->offset), sizeof(m_data->offset)) < 0)
+    if (bdrv_pwrite_sync(
+            extent->file,
+            ((int64_t)m_data->l2_offset * 512) + (m_data->l2_index *
sizeof(m_data->offset)),
+            &(m_data->offset),
+            sizeof(m_data->offset)
+        ) < 0)
         return -1;
     /* update backup L2 table */
-    if (s->l1_backup_table_offset != 0) {
-        m_data->l2_offset = s->l1_backup_table[m_data->l1_index];
-        if (bdrv_pwrite_sync(bs->file, ((int64_t)m_data->l2_offset *
512) + (m_data->l2_index * sizeof(m_data->offset)),
-                        &(m_data->offset), sizeof(m_data->offset)) < 0)
+    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(m_data->offset)),
+                &(m_data->offset), sizeof(m_data->offset)
+            ) < 0)
             return -1;
     }

     return 0;
 }

-static uint64_t get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
-                                   uint64_t offset, int allocate)
+static uint64_t get_cluster_offset(BlockDriverState *bs,
+                                    VmdkExtent *extent,
+                                    VmdkMetaData *m_data,
+                                    uint64_t offset, int allocate)
 {
-    BDRVVmdkState *s = bs->opaque;
     unsigned int l1_index, l2_offset, l2_index;
     int min_index, i, j;
     uint32_t min_count, *l2_table, tmp = 0;
@@ -496,21 +543,21 @@ static uint64_t
get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
     if (m_data)
         m_data->valid = 0;

-    l1_index = (offset >> 9) / s->l1_entry_sectors;
-    if (l1_index >= s->l1_size)
+    l1_index = (offset >> 9) / extent->l1_entry_sectors;
+    if (l1_index >= extent->l1_size)
         return 0;
-    l2_offset = s->l1_table[l1_index];
+    l2_offset = extent->l1_table[l1_index];
     if (!l2_offset)
         return 0;
     for(i = 0; i < L2_CACHE_SIZE; i++) {
-        if (l2_offset == s->l2_cache_offsets[i]) {
+        if (l2_offset == extent->l2_cache_offsets[i]) {
             /* increment the hit count */
-            if (++s->l2_cache_counts[i] == 0xffffffff) {
+            if (++extent->l2_cache_counts[i] == 0xffffffff) {
                 for(j = 0; j < L2_CACHE_SIZE; j++) {
-                    s->l2_cache_counts[j] >>= 1;
+                    extent->l2_cache_counts[j] >>= 1;
                 }
             }
-            l2_table = s->l2_cache + (i * s->l2_size);
+            l2_table = extent->l2_cache + (i * extent->l2_size);
             goto found;
         }
     }
@@ -518,20 +565,24 @@ static uint64_t
get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
     min_index = 0;
     min_count = 0xffffffff;
     for(i = 0; i < L2_CACHE_SIZE; i++) {
-        if (s->l2_cache_counts[i] < min_count) {
-            min_count = s->l2_cache_counts[i];
+        if (extent->l2_cache_counts[i] < min_count) {
+            min_count = extent->l2_cache_counts[i];
             min_index = i;
         }
     }
-    l2_table = s->l2_cache + (min_index * s->l2_size);
-    if (bdrv_pread(bs->file, (int64_t)l2_offset * 512, l2_table,
s->l2_size * sizeof(uint32_t)) !=
-
  s->l2_size * sizeof(uint32_t))
+    l2_table = extent->l2_cache + (min_index * extent->l2_size);
+    if (bdrv_pread(
+            extent->file,
+            (int64_t)l2_offset * 512,
+            l2_table,
+            extent->l2_size * sizeof(uint32_t)
+        ) != extent->l2_size * sizeof(uint32_t))
         return 0;

-    s->l2_cache_offsets[min_index] = l2_offset;
-    s->l2_cache_counts[min_index] = 1;
+    extent->l2_cache_offsets[min_index] = l2_offset;
+    extent->l2_cache_counts[min_index] = 1;
  found:
-    l2_index = ((offset >> 9) / s->cluster_sectors) % s->l2_size;
+    l2_index = ((offset >> 9) / extent->cluster_sectors) % extent->l2_size;
     cluster_offset = le32_to_cpu(l2_table[l2_index]);

     if (!cluster_offset) {
@@ -539,8 +590,11 @@ static uint64_t
get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
             return 0;

         // Avoid the L2 tables update for the images that have snapshots.
-        cluster_offset = bdrv_getlength(bs->file);
-        bdrv_truncate(bs->file, cluster_offset + (s->cluster_sectors << 9));
+        cluster_offset = bdrv_getlength(extent->file);
+        bdrv_truncate(
+            extent->file,
+            cluster_offset + (extent->cluster_sectors << 9)
+        );

         cluster_offset >>= 9;
         tmp = cpu_to_le32(cluster_offset);
@@ -551,7 +605,8 @@ static uint64_t
get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
          * This problem may occur because of insufficient space on host disk
          * or inappropriate VM shutdown.
          */
-        if (get_whole_cluster(bs, cluster_offset, offset, allocate) == -1)
+        if (get_whole_cluster(
+                bs, extent, cluster_offset, offset, allocate) == -1)
             return 0;

         if (m_data) {
@@ -566,39 +621,72 @@ static uint64_t
get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
     return cluster_offset;
 }

+static int find_extent(BDRVVmdkState *s, int64_t sector_num, int start_idx)
+{
+    int ext_idx = start_idx;
+    while (ext_idx < s->num_extents
+            && sector_num >= s->extents[ext_idx].sectors) {
+        sector_num -= s->extents[ext_idx].sectors;
+        ext_idx++;
+    }
+    if (ext_idx == s->num_extents) return -1;
+    return ext_idx;
+}
+
 static int vmdk_is_allocated(BlockDriverState *bs, int64_t sector_num,
                              int nb_sectors, int *pnum)
 {
     BDRVVmdkState *s = bs->opaque;
-    int index_in_cluster, n;
-    uint64_t cluster_offset;

-    cluster_offset = get_cluster_offset(bs, NULL, sector_num << 9, 0);
-    index_in_cluster = sector_num % s->cluster_sectors;
-    n = s->cluster_sectors - index_in_cluster;
+    int index_in_cluster, n, ret;
+    uint64_t offset;
+    VmdkExtent *extent;
+    int ext_idx;
+
+    ext_idx = find_extent(s, sector_num, 0);
+    if (ext_idx == -1) return 0;
+    extent = &s->extents[ext_idx];
+    if (s->extents[ext_idx].flat) {
+        n = extent->sectors - sector_num;
+        ret = 1;
+    } else {
+        offset = get_cluster_offset(bs, extent, NULL, sector_num * 512, 0);
+        index_in_cluster = sector_num % extent->cluster_sectors;
+        n = extent->cluster_sectors - index_in_cluster;
+        ret = offset ? 1 : 0;
+    }
     if (n > nb_sectors)
         n = nb_sectors;
     *pnum = n;
-    return (cluster_offset != 0);
+    return ret;
 }

 static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
                     uint8_t *buf, int nb_sectors)
 {
     BDRVVmdkState *s = bs->opaque;
-    int index_in_cluster, n, ret;
+    int ext_idx = 0;
+    int ret;
+    uint64_t n, index_in_cluster;
+    VmdkExtent *extent;
     uint64_t cluster_offset;

     while (nb_sectors > 0) {
-        cluster_offset = get_cluster_offset(bs, NULL, sector_num << 9, 0);
-        index_in_cluster = sector_num % s->cluster_sectors;
-        n = s->cluster_sectors - index_in_cluster;
+        ext_idx = find_extent(s, sector_num, ext_idx);
+        if (ext_idx == -1) {
+            return -1;
+        }
+        extent = &s->extents[ext_idx];
+        cluster_offset = get_cluster_offset(
+                            bs, extent, NULL, sector_num << 9, 0);
+        index_in_cluster = sector_num % extent->cluster_sectors;
+        n = extent->cluster_sectors - index_in_cluster;
         if (n > nb_sectors)
             n = nb_sectors;
         if (!cluster_offset) {
             // try to read from parent image, if exist
             if (bs->backing_hd) {
-                if (!vmdk_is_cid_valid(bs))
+                if (!vmdk_is_cid_valid(bs, extent))
                     return -1;
                 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
                 if (ret < 0)
@@ -621,10 +709,12 @@ static int vmdk_write(BlockDriverState *bs,
int64_t sector_num,
                      const uint8_t *buf, int nb_sectors)
 {
     BDRVVmdkState *s = bs->opaque;
-    VmdkMetaData m_data;
-    int index_in_cluster, n;
+    VmdkExtent *extent;
+    int ext_idx = 0;
+    int n, index_in_cluster;
     uint64_t cluster_offset;
     static int cid_update = 0;
+    VmdkMetaData m_data;

     if (sector_num > bs->total_sectors) {
         fprintf(stderr,
@@ -635,19 +725,28 @@ static int vmdk_write(BlockDriverState *bs,
int64_t sector_num,
     }

     while (nb_sectors > 0) {
-        index_in_cluster = sector_num & (s->cluster_sectors - 1);
-        n = s->cluster_sectors - index_in_cluster;
-        if (n > nb_sectors)
-            n = nb_sectors;
-        cluster_offset = get_cluster_offset(bs, &m_data, sector_num << 9, 1);
+        ext_idx = find_extent(s, sector_num, ext_idx);
+        if (ext_idx == -1) {
+            return -1;
+        }
+        extent = &s->extents[ext_idx];
+        cluster_offset = get_cluster_offset(
+                                bs,
+                                extent,
+                                &m_data,
+                                sector_num << 9, 1);
         if (!cluster_offset)
             return -1;
+        index_in_cluster = sector_num & (extent->cluster_sectors - 1);
+        n = extent->cluster_sectors - index_in_cluster;
+        if (n > nb_sectors)
+            n = nb_sectors;

         if (bdrv_pwrite(bs->file, cluster_offset + index_in_cluster *
512, buf, n * 512) != n * 512)
             return -1;
         if (m_data.valid) {
             /* update L2 tables */
-            if (vmdk_L2update(bs, &m_data) == -1)
+            if (vmdk_L2update(extent, &m_data) == -1)
                 return -1;
         }
         nb_sectors -= n;
@@ -818,8 +917,8 @@ static void vmdk_close(BlockDriverState *bs)
 {
     BDRVVmdkState *s = bs->opaque;

-    qemu_free(s->l1_table);
-    qemu_free(s->l2_cache);
+    qemu_free(s->extents[0].l1_table);
+    qemu_free(s->extents[0].l2_cache);
 }

 static int vmdk_flush(BlockDriverState *bs)