[Qemu-devel] [PATCH 1/2] qemu-img: Don't allow preallocation and compression at the same time

[Qemu-devel] [PATCH 1/2] qemu-img: Don't allow preallocation and compression at the same time

[Kevin Wolf]

Only qcow and qcow2 can do compression at all, and they require unallocated
clusters when writing the compressed data.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu-img.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index 6a39731..511f136 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -824,6 +824,8 @@ static int img_convert(int argc, char **argv)
     if (compress) {
         QEMUOptionParameter *encryption =
             get_option_parameter(param, BLOCK_OPT_ENCRYPT);
+        QEMUOptionParameter *preallocation =
+            get_option_parameter(param, BLOCK_OPT_PREALLOC);
 
         if (!drv->bdrv_write_compressed) {
             error_report("Compression not supported for this file format");
@@ -837,6 +839,13 @@ static int img_convert(int argc, char **argv)
             ret = -1;
             goto out;
         }
+
+        if (preallocation && strcmp(preallocation->value.s, "off")) {
+            error_report("Compression and preallocation not supported at "
+                         "the same time");
+            ret = -1;
+            goto out;
+        }
     }
 
     /* Create the new image */
-- 
1.7.6.4

[Qemu-devel] [PATCH 2/2] qcow2: Fix bdrv_write_compressed error handling

[Kevin Wolf]

If during allocation of compressed clusters the cluster was already allocated
uncompressed, fail and properly release the l2_table (the latter avoids a
failed assertion).

While at it, make it return some real error numbers instead of -1.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qcow2-cluster.c |    6 ++++--
 block/qcow2.c         |   11 ++++++-----
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 2f76311..f4e049f 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -568,8 +568,10 @@ uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
     }
 
     cluster_offset = be64_to_cpu(l2_table[l2_index]);
-    if (cluster_offset & QCOW_OFLAG_COPIED)
-        return cluster_offset & ~QCOW_OFLAG_COPIED;
+    if (cluster_offset & QCOW_OFLAG_COPIED) {
+        qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+        return 0;
+    }
 
     if (cluster_offset)
         qcow2_free_any_clusters(bs, cluster_offset, 1);
diff --git a/block/qcow2.c b/block/qcow2.c
index 4dc980c..bf399f3 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1054,7 +1054,7 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
                        9, Z_DEFAULT_STRATEGY);
     if (ret != 0) {
         g_free(out_buf);
-        return -1;
+        return -EINVAL;
     }
 
     strm.avail_in = s->cluster_size;
@@ -1066,7 +1066,7 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
     if (ret != Z_STREAM_END && ret != Z_OK) {
         g_free(out_buf);
         deflateEnd(&strm);
-        return -1;
+        return -EINVAL;
     }
     out_len = strm.next_out - out_buf;
 
@@ -1079,12 +1079,13 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
         cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
             sector_num << 9, out_len);
         if (!cluster_offset)
-            return -1;
+            return -EIO;
         cluster_offset &= s->cluster_offset_mask;
         BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
-        if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
+        ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
+        if (ret < 0) {
             g_free(out_buf);
-            return -1;
+            return ret;
         }
     }
 
-- 
1.7.6.4

Re: [Qemu-devel] [PATCH 1/2] qemu-img: Don't allow preallocation and compression at the same time

[Stefan Hajnoczi]

On Tue, Oct 18, 2011 at 8:47 AM, Kevin Wolf <kwolf@redhat.com> wrote:
> Only qcow and qcow2 can do compression at all, and they require unallocated
> clusters when writing the compressed data.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  qemu-img.c |    9 +++++++++
>  1 files changed, 9 insertions(+), 0 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>