qcow2: Add cluster type parameter to qcow2_get_host_offset()

This function returns an integer that can be either an error code or a
cluster type (a value from the QCow2ClusterType enum).

We are going to start using subcluster types instead of cluster types
in some functions so it's better to use the exact data types instead
of integers for clarity and in order to detect errors more easily.

This patch makes qcow2_get_host_offset() return 0 on success and
puts the returned cluster type in a separate parameter. There are no
semantic changes.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <396b6eab1859a271551dcd7dcba77f8934aa3c3f.1594396418.git.berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 22 insertions, 15 deletions

diff --git a/block/qcow2.c b/block/qcow2.c
index edbf9fb..070f89c 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2043,6 +2043,7 @@ static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs,
     BDRVQcow2State *s = bs->opaque;
     uint64_t host_offset;
     unsigned int bytes;
+    QCow2ClusterType type;
     int ret, status = 0;
 
     qemu_co_mutex_lock(&s->lock);
@@ -2054,7 +2055,7 @@ static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs,
     }
 
     bytes = MIN(INT_MAX, count);
-    ret = qcow2_get_host_offset(bs, offset, &bytes, &host_offset);
+    ret = qcow2_get_host_offset(bs, offset, &bytes, &host_offset, &type);
     qemu_co_mutex_unlock(&s->lock);
     if (ret < 0) {
         return ret;
@@ -2062,15 +2063,15 @@ static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs,
 
     *pnum = bytes;
 
-    if ((ret == QCOW2_CLUSTER_NORMAL || ret == QCOW2_CLUSTER_ZERO_ALLOC) &&
+    if ((type == QCOW2_CLUSTER_NORMAL || type == QCOW2_CLUSTER_ZERO_ALLOC) &&
         !s->crypto) {
         *map = host_offset;
         *file = s->data_file->bs;
         status |= BDRV_BLOCK_OFFSET_VALID;
     }
-    if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) {
+    if (type == QCOW2_CLUSTER_ZERO_PLAIN || type == QCOW2_CLUSTER_ZERO_ALLOC) {
         status |= BDRV_BLOCK_ZERO;
-    } else if (ret != QCOW2_CLUSTER_UNALLOCATED) {
+    } else if (type != QCOW2_CLUSTER_UNALLOCATED) {
         status |= BDRV_BLOCK_DATA;
     }
     if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) &&
@@ -2279,6 +2280,7 @@ static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
     int ret = 0;
     unsigned int cur_bytes; /* number of bytes in current iteration */
     uint64_t host_offset = 0;
+    QCow2ClusterType type;
     AioTaskPool *aio = NULL;
 
     while (bytes != 0 && aio_task_pool_status(aio) == 0) {
@@ -2290,22 +2292,23 @@ static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
         }
 
         qemu_co_mutex_lock(&s->lock);
-        ret = qcow2_get_host_offset(bs, offset, &cur_bytes, &host_offset);
+        ret = qcow2_get_host_offset(bs, offset, &cur_bytes,
+                                    &host_offset, &type);
         qemu_co_mutex_unlock(&s->lock);
         if (ret < 0) {
             goto out;
         }
 
-        if (ret == QCOW2_CLUSTER_ZERO_PLAIN ||
-            ret == QCOW2_CLUSTER_ZERO_ALLOC ||
-            (ret == QCOW2_CLUSTER_UNALLOCATED && !bs->backing))
+        if (type == QCOW2_CLUSTER_ZERO_PLAIN ||
+            type == QCOW2_CLUSTER_ZERO_ALLOC ||
+            (type == QCOW2_CLUSTER_UNALLOCATED && !bs->backing))
         {
             qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
         } else {
             if (!aio && cur_bytes != bytes) {
                 aio = aio_task_pool_new(QCOW2_MAX_WORKERS);
             }
-            ret = qcow2_add_task(bs, aio, qcow2_co_preadv_task_entry, ret,
+            ret = qcow2_add_task(bs, aio, qcow2_co_preadv_task_entry, type,
                                  host_offset, offset, cur_bytes,
                                  qiov, qiov_offset, NULL);
             if (ret < 0) {
@@ -3834,6 +3837,7 @@ static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
     if (head || tail) {
         uint64_t off;
         unsigned int nr;
+        QCow2ClusterType type;
 
         assert(head + bytes <= s->cluster_size);
 
@@ -3849,10 +3853,11 @@ static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
         offset = QEMU_ALIGN_DOWN(offset, s->cluster_size);
         bytes = s->cluster_size;
         nr = s->cluster_size;
-        ret = qcow2_get_host_offset(bs, offset, &nr, &off);
-        if (ret != QCOW2_CLUSTER_UNALLOCATED &&
-            ret != QCOW2_CLUSTER_ZERO_PLAIN &&
-            ret != QCOW2_CLUSTER_ZERO_ALLOC) {
+        ret = qcow2_get_host_offset(bs, offset, &nr, &off, &type);
+        if (ret < 0 ||
+            (type != QCOW2_CLUSTER_UNALLOCATED &&
+             type != QCOW2_CLUSTER_ZERO_PLAIN &&
+             type != QCOW2_CLUSTER_ZERO_ALLOC)) {
             qemu_co_mutex_unlock(&s->lock);
             return -ENOTSUP;
         }
@@ -3916,16 +3921,18 @@ qcow2_co_copy_range_from(BlockDriverState *bs,
 
     while (bytes != 0) {
         uint64_t copy_offset = 0;
+        QCow2ClusterType type;
         /* prepare next request */
         cur_bytes = MIN(bytes, INT_MAX);
         cur_write_flags = write_flags;
 
-        ret = qcow2_get_host_offset(bs, src_offset, &cur_bytes, &copy_offset);
+        ret = qcow2_get_host_offset(bs, src_offset, &cur_bytes,
+                                    &copy_offset, &type);
         if (ret < 0) {
             goto out;
         }
 
-        switch (ret) {
+        switch (type) {
         case QCOW2_CLUSTER_UNALLOCATED:
             if (bs->backing && bs->backing->bs) {
                 int64_t backing_length = bdrv_getlength(bs->backing->bs);