[Qemu-devel] [PATCH v2 13/17] vmdk: Implement .bdrv_co_pwritev() interface

[Kevin Wolf <kwolf@redhat.com>]

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/vmdk.c | 209 ++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 135 insertions(+), 74 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 6c447ad..f243527 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1016,27 +1016,26 @@ static void vmdk_refresh_limits(BlockDriverState *bs, Error **errp)
  */
 static int get_whole_cluster(BlockDriverState *bs,
                              VmdkExtent *extent,
-                             uint64_t cluster_sector_num,
-                             uint64_t sector_num,
-                             uint64_t skip_start_sector,
-                             uint64_t skip_end_sector)
+                             uint64_t cluster_offset,
+                             uint64_t offset,
+                             uint64_t skip_start_bytes,
+                             uint64_t skip_end_bytes)
 {
     int ret = VMDK_OK;
     int64_t cluster_bytes;
     uint8_t *whole_grain;
 
     /* For COW, align request sector_num to cluster start */
-    sector_num = QEMU_ALIGN_DOWN(sector_num, extent->cluster_sectors);
     cluster_bytes = extent->cluster_sectors << BDRV_SECTOR_BITS;
+    offset = QEMU_ALIGN_DOWN(offset, cluster_bytes);
     whole_grain = qemu_blockalign(bs, cluster_bytes);
 
     if (!bs->backing) {
-        memset(whole_grain, 0,  skip_start_sector << BDRV_SECTOR_BITS);
-        memset(whole_grain + (skip_end_sector << BDRV_SECTOR_BITS), 0,
-               cluster_bytes - (skip_end_sector << BDRV_SECTOR_BITS));
+        memset(whole_grain, 0, skip_start_bytes);
+        memset(whole_grain + skip_end_bytes, 0, cluster_bytes - skip_end_bytes);
     }
 
-    assert(skip_end_sector <= extent->cluster_sectors);
+    assert(skip_end_bytes <= cluster_bytes);
     /* 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 && !vmdk_is_cid_valid(bs)) {
@@ -1045,42 +1044,43 @@ static int get_whole_cluster(BlockDriverState *bs,
     }
 
     /* Read backing data before skip range */
-    if (skip_start_sector > 0) {
+    if (skip_start_bytes > 0) {
         if (bs->backing) {
-            ret = bdrv_read(bs->backing->bs, sector_num,
-                            whole_grain, skip_start_sector);
+            ret = bdrv_pread(bs->backing->bs, offset, whole_grain,
+                             skip_start_bytes);
             if (ret < 0) {
                 ret = VMDK_ERROR;
                 goto exit;
             }
         }
-        ret = bdrv_write(extent->file->bs, cluster_sector_num, whole_grain,
-                         skip_start_sector);
+        ret = bdrv_pwrite(extent->file->bs, cluster_offset, whole_grain,
+                          skip_start_bytes);
         if (ret < 0) {
             ret = VMDK_ERROR;
             goto exit;
         }
     }
     /* Read backing data after skip range */
-    if (skip_end_sector < extent->cluster_sectors) {
+    if (skip_end_bytes < cluster_bytes) {
         if (bs->backing) {
-            ret = bdrv_read(bs->backing->bs, sector_num + skip_end_sector,
-                            whole_grain + (skip_end_sector << BDRV_SECTOR_BITS),
-                            extent->cluster_sectors - skip_end_sector);
+            ret = bdrv_pread(bs->backing->bs, offset + skip_end_bytes,
+                             whole_grain + skip_end_bytes,
+                             cluster_bytes - skip_end_bytes);
             if (ret < 0) {
                 ret = VMDK_ERROR;
                 goto exit;
             }
         }
-        ret = bdrv_write(extent->file->bs, cluster_sector_num + skip_end_sector,
-                         whole_grain + (skip_end_sector << BDRV_SECTOR_BITS),
-                         extent->cluster_sectors - skip_end_sector);
+        ret = bdrv_pwrite(extent->file->bs, cluster_offset + skip_end_bytes,
+                          whole_grain + skip_end_bytes,
+                          cluster_bytes - skip_end_bytes);
         if (ret < 0) {
             ret = VMDK_ERROR;
             goto exit;
         }
     }
 
+    ret = VMDK_OK;
 exit:
     qemu_vfree(whole_grain);
     return ret;
@@ -1142,8 +1142,8 @@ static int get_cluster_offset(BlockDriverState *bs,
                               uint64_t offset,
                               bool allocate,
                               uint64_t *cluster_offset,
-                              uint64_t skip_start_sector,
-                              uint64_t skip_end_sector)
+                              uint64_t skip_start_bytes,
+                              uint64_t skip_end_bytes)
 {
     unsigned int l1_index, l2_offset, l2_index;
     int min_index, i, j;
@@ -1230,10 +1230,8 @@ static int get_cluster_offset(BlockDriverState *bs,
          * This problem may occur because of insufficient space on host disk
          * or inappropriate VM shutdown.
          */
-        ret = get_whole_cluster(bs, extent,
-                                cluster_sector,
-                                offset >> BDRV_SECTOR_BITS,
-                                skip_start_sector, skip_end_sector);
+        ret = get_whole_cluster(bs, extent, cluster_sector * BDRV_SECTOR_SIZE,
+                                offset, skip_start_bytes, skip_end_bytes);
         if (ret) {
             return ret;
         }
@@ -1330,38 +1328,57 @@ static int64_t coroutine_fn vmdk_co_get_block_status(BlockDriverState *bs,
 }
 
 static int vmdk_write_extent(VmdkExtent *extent, int64_t cluster_offset,
-                            int64_t offset_in_cluster, const uint8_t *buf,
-                            int nb_sectors, int64_t sector_num)
+                            int64_t offset_in_cluster, QEMUIOVector *qiov,
+                            uint64_t qiov_offset, uint64_t n_bytes,
+                            uint64_t offset)
 {
     int ret;
     VmdkGrainMarker *data = NULL;
     uLongf buf_len;
-    const uint8_t *write_buf = buf;
-    int write_len = nb_sectors * 512;
+    QEMUIOVector local_qiov;
+    struct iovec iov;
     int64_t write_offset;
     int64_t write_end_sector;
 
     if (extent->compressed) {
+        void *compressed_data;
+
         if (!extent->has_marker) {
             ret = -EINVAL;
             goto out;
         }
         buf_len = (extent->cluster_sectors << 9) * 2;
         data = g_malloc(buf_len + sizeof(VmdkGrainMarker));
-        if (compress(data->data, &buf_len, buf, nb_sectors << 9) != Z_OK ||
-                buf_len == 0) {
+
+        compressed_data = g_malloc(n_bytes);
+        qemu_iovec_to_buf(qiov, qiov_offset, compressed_data, n_bytes);
+        ret = compress(data->data, &buf_len, compressed_data, n_bytes);
+        g_free(compressed_data);
+
+        if (ret != Z_OK || buf_len == 0) {
             ret = -EINVAL;
             goto out;
         }
-        data->lba = sector_num;
+
+        data->lba = offset >> BDRV_SECTOR_BITS;
         data->size = buf_len;
-        write_buf = (uint8_t *)data;
-        write_len = buf_len + sizeof(VmdkGrainMarker);
+
+        n_bytes = buf_len + sizeof(VmdkGrainMarker);
+        iov = (struct iovec) {
+            .iov_base   = data,
+            .iov_len    = n_bytes,
+        };
+        qemu_iovec_init_external(&local_qiov, &iov, 1);
+    } else {
+        qemu_iovec_init(&local_qiov, qiov->niov);
+        qemu_iovec_concat(&local_qiov, qiov, qiov_offset, n_bytes);
     }
+
     write_offset = cluster_offset + offset_in_cluster,
-    ret = bdrv_pwrite(extent->file->bs, write_offset, write_buf, write_len);
+    ret = bdrv_co_pwritev(extent->file->bs, write_offset, n_bytes,
+                          &local_qiov, 0);
 
-    write_end_sector = DIV_ROUND_UP(write_offset + write_len, BDRV_SECTOR_SIZE);
+    write_end_sector = DIV_ROUND_UP(write_offset + n_bytes, BDRV_SECTOR_SIZE);
 
     if (extent->compressed) {
         extent->next_cluster_sector = write_end_sector;
@@ -1370,13 +1387,15 @@ static int vmdk_write_extent(VmdkExtent *extent, int64_t cluster_offset,
                                           write_end_sector);
     }
 
-    if (ret != write_len) {
-        ret = ret < 0 ? ret : -EIO;
+    if (ret < 0) {
         goto out;
     }
     ret = 0;
  out:
     g_free(data);
+    if (!extent->compressed) {
+        qemu_iovec_destroy(&local_qiov);
+    }
     return ret;
 }
 
@@ -1525,38 +1544,38 @@ fail:
  *
  * Returns: error code with 0 for success.
  */
-static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
-                      const uint8_t *buf, int nb_sectors,
-                      bool zeroed, bool zero_dry_run)
+static int vmdk_pwritev(BlockDriverState *bs, uint64_t offset,
+                       uint64_t bytes, QEMUIOVector *qiov,
+                       bool zeroed, bool zero_dry_run)
 {
     BDRVVmdkState *s = bs->opaque;
     VmdkExtent *extent = NULL;
     int ret;
-    int64_t index_in_cluster, n;
+    int64_t offset_in_cluster, n_bytes;
     uint64_t cluster_offset;
+    uint64_t bytes_done = 0;
     VmdkMetaData m_data;
 
-    if (sector_num > bs->total_sectors) {
-        error_report("Wrong offset: sector_num=0x%" PRIx64
+    if (DIV_ROUND_UP(offset, BDRV_SECTOR_SIZE) > bs->total_sectors) {
+        error_report("Wrong offset: offset=0x%" PRIx64
                      " total_sectors=0x%" PRIx64,
-                     sector_num, bs->total_sectors);
+                     offset, bs->total_sectors);
         return -EIO;
     }
 
-    while (nb_sectors > 0) {
-        extent = find_extent(s, sector_num, extent);
+    while (bytes > 0) {
+        extent = find_extent(s, offset >> BDRV_SECTOR_BITS, extent);
         if (!extent) {
             return -EIO;
         }
-        index_in_cluster = vmdk_find_index_in_cluster(extent, sector_num);
-        n = extent->cluster_sectors - index_in_cluster;
-        if (n > nb_sectors) {
-            n = nb_sectors;
-        }
-        ret = get_cluster_offset(bs, extent, &m_data, sector_num << 9,
+        offset_in_cluster = vmdk_find_offset_in_cluster(extent, offset);
+        n_bytes = MIN(bytes, extent->cluster_sectors * BDRV_SECTOR_SIZE
+                             - offset_in_cluster);
+
+        ret = get_cluster_offset(bs, extent, &m_data, offset,
                                  !(extent->compressed || zeroed),
-                                 &cluster_offset,
-                                 index_in_cluster, index_in_cluster + n);
+                                 &cluster_offset, offset_in_cluster,
+                                 offset_in_cluster + n_bytes);
         if (extent->compressed) {
             if (ret == VMDK_OK) {
                 /* Refuse write to allocated cluster for streamOptimized */
@@ -1565,7 +1584,7 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
                 return -EIO;
             } else {
                 /* allocate */
-                ret = get_cluster_offset(bs, extent, &m_data, sector_num << 9,
+                ret = get_cluster_offset(bs, extent, &m_data, offset,
                                          true, &cluster_offset, 0, 0);
             }
         }
@@ -1575,9 +1594,9 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
         if (zeroed) {
             /* Do zeroed write, buf is ignored */
             if (extent->has_zero_grain &&
-                    index_in_cluster == 0 &&
-                    n >= extent->cluster_sectors) {
-                n = extent->cluster_sectors;
+                    offset_in_cluster == 0 &&
+                    n_bytes >= extent->cluster_sectors * BDRV_SECTOR_SIZE) {
+                n_bytes = extent->cluster_sectors * BDRV_SECTOR_SIZE;
                 if (!zero_dry_run) {
                     /* update L2 tables */
                     if (vmdk_L2update(extent, &m_data, VMDK_GTE_ZEROED)
@@ -1589,9 +1608,8 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
                 return -ENOTSUP;
             }
         } else {
-            ret = vmdk_write_extent(extent,
-                            cluster_offset, index_in_cluster * 512,
-                            buf, n, sector_num);
+            ret = vmdk_write_extent(extent, cluster_offset, offset_in_cluster,
+                                    qiov, bytes_done, n_bytes, offset);
             if (ret) {
                 return ret;
             }
@@ -1604,9 +1622,9 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
                 }
             }
         }
-        nb_sectors -= n;
-        sector_num += n;
-        buf += n * 512;
+        bytes -= n_bytes;
+        offset += n_bytes;
+        bytes_done += n_bytes;
 
         /* update CID on the first write every time the virtual disk is
          * opened */
@@ -1621,25 +1639,65 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
     return 0;
 }
 
-static coroutine_fn int vmdk_co_write(BlockDriverState *bs, int64_t sector_num,
-                                      const uint8_t *buf, int nb_sectors)
+static int coroutine_fn
+vmdk_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
+                QEMUIOVector *qiov, int flags)
 {
     int ret;
     BDRVVmdkState *s = bs->opaque;
     qemu_co_mutex_lock(&s->lock);
-    ret = vmdk_write(bs, sector_num, buf, nb_sectors, false, false);
+    ret = vmdk_pwritev(bs, offset, bytes, qiov, false, false);
     qemu_co_mutex_unlock(&s->lock);
     return ret;
 }
 
+typedef struct VmdkWriteCompressedCo {
+    BlockDriverState *bs;
+    int64_t sector_num;
+    const uint8_t *buf;
+    int nb_sectors;
+    int ret;
+} VmdkWriteCompressedCo;
+
+static void vmdk_co_write_compressed(void *opaque)
+{
+    VmdkWriteCompressedCo *co = opaque;
+    QEMUIOVector local_qiov;
+    uint64_t offset = co->sector_num * BDRV_SECTOR_SIZE;
+    uint64_t bytes = co->nb_sectors * BDRV_SECTOR_SIZE;
+
+    struct iovec iov = (struct iovec) {
+        .iov_base   = (uint8_t*) co->buf,
+        .iov_len    = bytes,
+    };
+    qemu_iovec_init_external(&local_qiov, &iov, 1);
+
+    co->ret = vmdk_pwritev(co->bs, offset, bytes, &local_qiov, false, false);
+}
+
 static int vmdk_write_compressed(BlockDriverState *bs,
                                  int64_t sector_num,
                                  const uint8_t *buf,
                                  int nb_sectors)
 {
     BDRVVmdkState *s = bs->opaque;
+
     if (s->num_extents == 1 && s->extents[0].compressed) {
-        return vmdk_write(bs, sector_num, buf, nb_sectors, false, false);
+        Coroutine *co;
+        AioContext *aio_context = bdrv_get_aio_context(bs);
+        VmdkWriteCompressedCo data = {
+            .bs         = bs,
+            .sector_num = sector_num,
+            .buf        = buf,
+            .nb_sectors = nb_sectors,
+            .ret        = -EINPROGRESS,
+        };
+        co = qemu_coroutine_create(vmdk_co_write_compressed);
+        qemu_coroutine_enter(co, &data);
+        while (data.ret == -EINPROGRESS) {
+            aio_poll(aio_context, true);
+        }
+        return data.ret;
     } else {
         return -ENOTSUP;
     }
@@ -1652,12 +1710,15 @@ static int coroutine_fn vmdk_co_write_zeroes(BlockDriverState *bs,
 {
     int ret;
     BDRVVmdkState *s = bs->opaque;
+    uint64_t offset = sector_num * BDRV_SECTOR_SIZE;
+    uint64_t bytes = nb_sectors * BDRV_SECTOR_SIZE;
+
     qemu_co_mutex_lock(&s->lock);
     /* write zeroes could fail if sectors not aligned to cluster, test it with
      * dry_run == true before really updating image */
-    ret = vmdk_write(bs, sector_num, NULL, nb_sectors, true, true);
+    ret = vmdk_pwritev(bs, offset, bytes, NULL, true, true);
     if (!ret) {
-        ret = vmdk_write(bs, sector_num, NULL, nb_sectors, true, false);
+        ret = vmdk_pwritev(bs, offset, bytes, NULL, true, false);
     }
     qemu_co_mutex_unlock(&s->lock);
     return ret;
@@ -2341,7 +2402,7 @@ static BlockDriver bdrv_vmdk = {
     .bdrv_check                   = vmdk_check,
     .bdrv_reopen_prepare          = vmdk_reopen_prepare,
     .bdrv_co_preadv               = vmdk_co_preadv,
-    .bdrv_write                   = vmdk_co_write,
+    .bdrv_co_pwritev              = vmdk_co_pwritev,
     .bdrv_write_compressed        = vmdk_write_compressed,
     .bdrv_co_write_zeroes         = vmdk_co_write_zeroes,
     .bdrv_close                   = vmdk_close,
-- 
1.8.3.1