diff mbox

[RFC,v11,6/6] qcow2: Add falloc and full preallocation option

Message ID 6583fb5f97a6d173be3865d2794ceb3cccf7c013.1404287261.git.hutao@cn.fujitsu.com
State New
Headers show

Commit Message

Hu Tao July 2, 2014, 8:17 a.m. UTC 
This adds preallocation=falloc and preallocation=full mode to qcow2
image creation.

preallocation=full allocates disk space by writing zeros to disk to
ensure disk space in any cases.

preallocation=falloc likes preallocation=full, but allocates disk space
by posix_fallocate().

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 block/qcow2.c              | 29 ++++++++++++++++++++++++-
 tests/qemu-iotests/082.out | 54 +++++++++++++++++++++++-----------------------
 2 files changed, 55 insertions(+), 28 deletions(-)

Comments

Max Reitz July 3, 2014, 8:30 p.m. UTC | #1 
On 02.07.2014 10:17, Hu Tao wrote:
> This adds preallocation=falloc and preallocation=full mode to qcow2
> image creation.
>
> preallocation=full allocates disk space by writing zeros to disk to
> ensure disk space in any cases.
>
> preallocation=falloc likes preallocation=full, but allocates disk space
> by posix_fallocate().
>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>   block/qcow2.c              | 29 ++++++++++++++++++++++++-
>   tests/qemu-iotests/082.out | 54 +++++++++++++++++++++++-----------------------
>   2 files changed, 55 insertions(+), 28 deletions(-)
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index cfba93b..f2df8cb 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1593,6 +1593,9 @@ static int preallocate(BlockDriverState *bs)
>       return 0;
>   }
>   
> +static uint64_t minimal_blob_size(uint64_t ts, int cb, int spcb,
> +                                  uint64_t overhead);
> +
>   static int qcow2_create2(const char *filename, int64_t total_size,
>                            const char *backing_file, const char *backing_format,
>                            int flags, size_t cluster_size, PreallocMode prealloc,
> @@ -1628,6 +1631,29 @@ static int qcow2_create2(const char *filename, int64_t total_size,
>       Error *local_err = NULL;
>       int ret;
>   
> +    if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
> +        int64_t meta_size = 0;
> +        unsigned nl2e;
> +
> +        total_size = align_offset(total_size, cluster_size);
> +
> +        /* total size of L2 tables */
> +        nl2e = total_size / cluster_size;

This might overflow, better use a uint64_t for nl2e. Also: You're using 
">> cluster_bits" below to divide by the cluster size; I'd prefer using 
the same method in both places (either ">> cluster_bits" or "/ 
cluster_size").

> +        nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
> +        uint64_t l2_clusters = nl2e * sizeof(uint64_t) >> cluster_bits;
> +
> +        meta_size =
> +            (1 +
> +             minimal_blob_size(total_size / BDRV_SECTOR_SIZE,
> +                               cluster_bits, cluster_bits - BDRV_SECTOR_BITS,
> +                               1 + l2_clusters +
> +                               (total_size >> cluster_bits)) +
> +             l2_clusters) << cluster_bits;
> +
> +        qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size + meta_size);
> +        qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc]);
> +    }
> +
>       ret = bdrv_create_file(filename, opts, &local_err);
>       if (ret < 0) {
>           error_propagate(errp, local_err);

Maybe I'd additionally change the "if (prealloc)" later in 
qcow2_create2() to "if (prealloc != PREALLOC_MODE_NONE)" to make it more 
clear that there is more than just one method of preallocation now.


Maybe we also want to modify preallocate() later on to allocate all 
metadata structures in a single block (because, who knows, we might want 
a linear layout for the data clusters for some strange reason), but 
currently there is no need for that.

Reviewed-by: Max Reitz <mreitz@redhat.com>
Max Reitz July 3, 2014, 8:35 p.m. UTC | #2 
On 02.07.2014 10:17, Hu Tao wrote:
> This adds preallocation=falloc and preallocation=full mode to qcow2
> image creation.
>
> preallocation=full allocates disk space by writing zeros to disk to
> ensure disk space in any cases.
>
> preallocation=falloc likes preallocation=full, but allocates disk space
> by posix_fallocate().
>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>   block/qcow2.c              | 29 ++++++++++++++++++++++++-
>   tests/qemu-iotests/082.out | 54 +++++++++++++++++++++++-----------------------
>   2 files changed, 55 insertions(+), 28 deletions(-)

Ah, I missed something: You'll need to fix the output of test 049 as 
well ("Invalid preallocation mode: '1234'" -> "invalid parameter value: 
1234").

Max
diff mbox

Patch

diff --git a/block/qcow2.c b/block/qcow2.c
index cfba93b..f2df8cb 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1593,6 +1593,9 @@  static int preallocate(BlockDriverState *bs)
     return 0;
 }
 
+static uint64_t minimal_blob_size(uint64_t ts, int cb, int spcb,
+                                  uint64_t overhead);
+
 static int qcow2_create2(const char *filename, int64_t total_size,
                          const char *backing_file, const char *backing_format,
                          int flags, size_t cluster_size, PreallocMode prealloc,
@@ -1628,6 +1631,29 @@  static int qcow2_create2(const char *filename, int64_t total_size,
     Error *local_err = NULL;
     int ret;
 
+    if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
+        int64_t meta_size = 0;
+        unsigned nl2e;
+
+        total_size = align_offset(total_size, cluster_size);
+
+        /* total size of L2 tables */
+        nl2e = total_size / cluster_size;
+        nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
+        uint64_t l2_clusters = nl2e * sizeof(uint64_t) >> cluster_bits;
+
+        meta_size =
+            (1 +
+             minimal_blob_size(total_size / BDRV_SECTOR_SIZE,
+                               cluster_bits, cluster_bits - BDRV_SECTOR_BITS,
+                               1 + l2_clusters +
+                               (total_size >> cluster_bits)) +
+             l2_clusters) << cluster_bits;
+
+        qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size + meta_size);
+        qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc]);
+    }
+
     ret = bdrv_create_file(filename, opts, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
@@ -2760,7 +2786,8 @@  static QemuOptsList qcow2_create_opts = {
         {
             .name = BLOCK_OPT_PREALLOC,
             .type = QEMU_OPT_STRING,
-            .help = "Preallocation mode (allowed values: off, metadata)"
+            .help = "Preallocation mode (allowed values: off, metadata, "
+                    "falloc, full)"
         },
         {
             .name = BLOCK_OPT_LAZY_REFCOUNTS,
diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out
index 28309a0..41324d5 100644
--- a/tests/qemu-iotests/082.out
+++ b/tests/qemu-iotests/082.out
@@ -64,7 +64,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o ? TEST_DIR/t.qcow2 128M
@@ -75,7 +75,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2 128M
@@ -86,7 +86,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2 128M
@@ -97,7 +97,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2 128M
@@ -108,7 +108,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2 128M
@@ -119,7 +119,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2 128M
@@ -130,7 +130,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2 128M
@@ -141,7 +141,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 128M
@@ -167,7 +167,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: create -o help
@@ -245,7 +245,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o ? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -256,7 +256,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -267,7 +267,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -278,7 +278,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -289,7 +289,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -300,7 +300,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -311,7 +311,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -322,7 +322,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -O qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -348,7 +348,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -o help
@@ -415,7 +415,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o ? TEST_DIR/t.qcow2
@@ -426,7 +426,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2
@@ -437,7 +437,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2
@@ -448,7 +448,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2
@@ -459,7 +459,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2
@@ -470,7 +470,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2
@@ -481,7 +481,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2
@@ -492,7 +492,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: amend -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2
@@ -520,7 +520,7 @@  backing_file     File name of a base image
 backing_fmt      Image format of the base image
 encryption       Encrypt the image
 cluster_size     qcow2 cluster size
-preallocation    Preallocation mode (allowed values: off, metadata)
+preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
 
 Testing: convert -o help