[Qemu-devel] [PATCH RFC v11 0/6] qcow2, raw: add preallocation=full and preallocation=falloc

[Qemu-devel] [PATCH RFC v11 0/6] qcow2, raw: add preallocation=full and preallocation=falloc

[Hu Tao]

Kevin,

This is v11 series for you to check how the series depends on Max's
minimal_blob_size(). I'm aware that you rejected the calculation of
metadata size, but posting this series so that you can comment on it.

This series depends on patches 1-3 of Max's series 'qemu-img: Implement
commit like QMP'.

Option preallocation=full preallocates disk space for image by writing
zeros to disk, this ensures disk space in any cases.

Option preallocation=falloc preallocates disk space by calling
posix_fallocate(). This is faster than preallocation=full. 

The series is also at https://github.com/taohu/qemu/commits/preallocation-v11
for you to check out.

changes to v10:

  - PreallocMode is moved from file qapi-schema.json to qapi/block-core.json
  - introdues preallocation=falloc, no changes to preallocation=metadata
  - using minimal_blob_size() to calculate metadata size for qcow2
  - indentation fix in file blockdev.c

Hu Tao (6):
  block: round up file size to nearest sector
  raw, qcow2: don't convert file size to sector size
  rename parse_enum_option to qapi_enum_parse and make it public
  qapi: introduce PreallocMode and a new PreallocMode full.
  raw-posix: Add falloc and full preallocation option
  qcow2: Add falloc and full preallocation option

 block/qcow2.c              | 54 ++++++++++++++++++++++++++++---------
 block/raw-posix.c          | 66 +++++++++++++++++++++++++++++++++++++++-------
 block/raw-win32.c          |  6 ++---
 blockdev.c                 | 30 +++++----------------
 include/qapi/util.h        | 17 ++++++++++++
 qapi/Makefile.objs         |  1 +
 qapi/block-core.json       | 17 ++++++++++++
 qapi/qapi-util.c           | 32 ++++++++++++++++++++++
 tests/qemu-iotests/082.out | 54 ++++++++++++++++++-------------------
 tests/qemu-iotests/096     | 64 ++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/096.out | 14 ++++++++++
 tests/qemu-iotests/group   |  1 +
 12 files changed, 280 insertions(+), 76 deletions(-)
 create mode 100644 include/qapi/util.h
 create mode 100644 qapi/qapi-util.c
 create mode 100755 tests/qemu-iotests/096
 create mode 100644 tests/qemu-iotests/096.out

-- 
1.9.3

[Qemu-devel] [PATCH RFC v11 1/6] block: round up file size to nearest sector

[Hu Tao]

Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 block/qcow2.c              |  3 ++-
 block/raw-posix.c          |  4 +--
 block/raw-win32.c          |  4 +--
 tests/qemu-iotests/096     | 64 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/096.out | 14 ++++++++++
 tests/qemu-iotests/group   |  1 +
 6 files changed, 85 insertions(+), 5 deletions(-)
 create mode 100755 tests/qemu-iotests/096
 create mode 100644 tests/qemu-iotests/096.out

diff --git a/block/qcow2.c b/block/qcow2.c
index 0aba8dd..0dfbb9a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1777,7 +1777,8 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
     int ret;
 
     /* Read out options */
-    sectors = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0) / 512;
+    sectors = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+                           BDRV_SECTOR_SIZE);
     backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
     backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
     if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
diff --git a/block/raw-posix.c b/block/raw-posix.c
index dacf4fb..b861bd9 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1282,8 +1282,8 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
     strstart(filename, "file:", &filename);
 
     /* Read out options */
-    total_size =
-        qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0) / BDRV_SECTOR_SIZE;
+    total_size = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+                              BDRV_SECTOR_SIZE);
 
     fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
                    0644);
diff --git a/block/raw-win32.c b/block/raw-win32.c
index 902eab6..1e1880d 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -511,8 +511,8 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
     strstart(filename, "file:", &filename);
 
     /* Read out options */
-    total_size =
-        qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0) / 512;
+    total_size = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+                              BDRV_SECTOR_SIZE);
 
     fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
                    0644);
diff --git a/tests/qemu-iotests/096 b/tests/qemu-iotests/096
new file mode 100755
index 0000000..1c2f6a3
--- /dev/null
+++ b/tests/qemu-iotests/096
@@ -0,0 +1,64 @@
+#!/bin/bash
+#
+# Test qcow2 creation with aligned and unaligned sizes
+#
+# Copyright (C) 2014 Fujitsu.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=hutao@cn.fujitsu.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+function test_qemu_img()
+{
+    echo qemu-img "$@" | _filter_testdir
+    $QEMU_IMG "$@" 2>&1 | _filter_testdir
+    echo
+}
+
+echo "=== Check qemu-img info output ==="
+echo
+image_sizes="1024 1234"
+
+for s in $image_sizes; do
+    _make_test_img $s
+    _img_info
+done
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/096.out b/tests/qemu-iotests/096.out
new file mode 100644
index 0000000..5f6c262
--- /dev/null
+++ b/tests/qemu-iotests/096.out
@@ -0,0 +1,14 @@
+QA output created by 096
+=== Check qemu-img info output ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1024 
+image: TEST_DIR/t.IMGFMT
+file format: IMGFMT
+virtual size: 1.0K (1024 bytes)
+cluster_size: 65536
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1234 
+image: TEST_DIR/t.IMGFMT
+file format: IMGFMT
+virtual size: 1.5K (1536 bytes)
+cluster_size: 65536
+***done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index e3dc4e8..65d04ee 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -100,3 +100,4 @@
 091 rw auto
 092 rw auto quick
 095 rw auto
+096 rw auto
-- 
1.9.3

[Qemu-devel] [PATCH RFC v11 2/6] raw, qcow2: don't convert file size to sector size

[Hu Tao]

and avoid converting it back later.

Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 block/qcow2.c     | 10 +++++-----
 block/raw-posix.c |  6 +++---
 block/raw-win32.c |  6 +++---
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 0dfbb9a..05df4b9 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1715,7 +1715,7 @@ static int qcow2_create2(const char *filename, int64_t total_size,
     }
 
     /* Okay, now that we have a valid image, let's give it the right size */
-    ret = bdrv_truncate(bs, total_size * BDRV_SECTOR_SIZE);
+    ret = bdrv_truncate(bs, total_size);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "Could not resize image");
         goto out;
@@ -1768,7 +1768,7 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
     char *backing_file = NULL;
     char *backing_fmt = NULL;
     char *buf = NULL;
-    uint64_t sectors = 0;
+    uint64_t size = 0;
     int flags = 0;
     size_t cluster_size = DEFAULT_CLUSTER_SIZE;
     int prealloc = 0;
@@ -1777,8 +1777,8 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
     int ret;
 
     /* Read out options */
-    sectors = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
-                           BDRV_SECTOR_SIZE);
+    size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+                    BDRV_SECTOR_SIZE);
     backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
     backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
     if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
@@ -1828,7 +1828,7 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
         goto finish;
     }
 
-    ret = qcow2_create2(filename, sectors, backing_file, backing_fmt, flags,
+    ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags,
                         cluster_size, prealloc, opts, version, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
diff --git a/block/raw-posix.c b/block/raw-posix.c
index b861bd9..58c51d8 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1282,8 +1282,8 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
     strstart(filename, "file:", &filename);
 
     /* Read out options */
-    total_size = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
-                              BDRV_SECTOR_SIZE);
+    total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+                          BDRV_SECTOR_SIZE);
 
     fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
                    0644);
@@ -1291,7 +1291,7 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
         result = -errno;
         error_setg_errno(errp, -result, "Could not create file");
     } else {
-        if (ftruncate(fd, total_size * BDRV_SECTOR_SIZE) != 0) {
+        if (ftruncate(fd, total_size) != 0) {
             result = -errno;
             error_setg_errno(errp, -result, "Could not resize file");
         }
diff --git a/block/raw-win32.c b/block/raw-win32.c
index 1e1880d..9bf8225 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -511,8 +511,8 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
     strstart(filename, "file:", &filename);
 
     /* Read out options */
-    total_size = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
-                              BDRV_SECTOR_SIZE);
+    total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+                          BDRV_SECTOR_SIZE);
 
     fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
                    0644);
@@ -521,7 +521,7 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
         return -EIO;
     }
     set_sparse(fd);
-    ftruncate(fd, total_size * 512);
+    ftruncate(fd, total_size);
     qemu_close(fd);
     return 0;
 }
-- 
1.9.3

[Qemu-devel] [PATCH RFC v11 3/6] rename parse_enum_option to qapi_enum_parse and make it public

[Hu Tao]

Suggested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 blockdev.c          | 30 ++++++------------------------
 include/qapi/util.h | 17 +++++++++++++++++
 qapi/Makefile.objs  |  1 +
 qapi/qapi-util.c    | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+), 24 deletions(-)
 create mode 100644 include/qapi/util.h
 create mode 100644 qapi/qapi-util.c

diff --git a/blockdev.c b/blockdev.c
index 69b7c2a..0967b93 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -39,6 +39,7 @@
 #include "qapi/qmp/types.h"
 #include "qapi-visit.h"
 #include "qapi/qmp-output-visitor.h"
+#include "qapi/util.h"
 #include "sysemu/sysemu.h"
 #include "block/block_int.h"
 #include "qmp-commands.h"
@@ -274,25 +275,6 @@ static int parse_block_error_action(const char *buf, bool is_read, Error **errp)
     }
 }
 
-static inline int parse_enum_option(const char *lookup[], const char *buf,
-                                    int max, int def, Error **errp)
-{
-    int i;
-
-    if (!buf) {
-        return def;
-    }
-
-    for (i = 0; i < max; i++) {
-        if (!strcmp(buf, lookup[i])) {
-            return i;
-        }
-    }
-
-    error_setg(errp, "invalid parameter value: %s", buf);
-    return def;
-}
-
 static bool check_throttle_config(ThrottleConfig *cfg, Error **errp)
 {
     if (throttle_conflicting(cfg)) {
@@ -456,11 +438,11 @@ static DriveInfo *blockdev_init(const char *file, QDict *bs_opts,
     }
 
     detect_zeroes =
-        parse_enum_option(BlockdevDetectZeroesOptions_lookup,
-                          qemu_opt_get(opts, "detect-zeroes"),
-                          BLOCKDEV_DETECT_ZEROES_OPTIONS_MAX,
-                          BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
-                          &error);
+        qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
+                        qemu_opt_get(opts, "detect-zeroes"),
+                        BLOCKDEV_DETECT_ZEROES_OPTIONS_MAX,
+                        BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
+                        &error);
     if (error) {
         error_propagate(errp, error);
         goto early_err;
diff --git a/include/qapi/util.h b/include/qapi/util.h
new file mode 100644
index 0000000..de9238b
--- /dev/null
+++ b/include/qapi/util.h
@@ -0,0 +1,17 @@
+/*
+ * QAPI util functions
+ *
+ * Copyright Fujitsu, Inc. 2014
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QAPI_UTIL_H
+#define QAPI_UTIL_H
+
+int qapi_enum_parse(const char *lookup[], const char *buf,
+                    int max, int def, Error **errp);
+
+#endif
diff --git a/qapi/Makefile.objs b/qapi/Makefile.objs
index d14b769..ffd88a6 100644
--- a/qapi/Makefile.objs
+++ b/qapi/Makefile.objs
@@ -4,3 +4,4 @@ util-obj-y += string-input-visitor.o string-output-visitor.o
 
 util-obj-y += opts-visitor.o
 util-obj-y += qmp-event.o
+util-obj-y += qapi-util.o
diff --git a/qapi/qapi-util.c b/qapi/qapi-util.c
new file mode 100644
index 0000000..3e4e07c
--- /dev/null
+++ b/qapi/qapi-util.c
@@ -0,0 +1,32 @@
+/*
+ * QAPI util functions
+ *
+ * Copyright Fujitsu, Inc. 2014
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qapi/util.h"
+
+int qapi_enum_parse(const char *lookup[], const char *buf,
+                    int max, int def, Error **errp)
+{
+    int i;
+
+    if (!buf) {
+        return def;
+    }
+
+    for (i = 0; i < max; i++) {
+        if (!strcmp(buf, lookup[i])) {
+            return i;
+        }
+    }
+
+    error_setg(errp, "invalid parameter value: %s", buf);
+    return def;
+}
-- 
1.9.3

[Qemu-devel] [PATCH RFC v11 4/6] qapi: introduce PreallocMode and a new PreallocMode full.

[Hu Tao]

This patch prepares for the subsequent patches.

Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 block/qcow2.c        | 16 ++++++++--------
 qapi/block-core.json | 17 +++++++++++++++++
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 05df4b9..cfba93b 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -30,6 +30,7 @@
 #include "qemu/error-report.h"
 #include "qapi/qmp/qerror.h"
 #include "qapi/qmp/qbool.h"
+#include "qapi/util.h"
 #include "trace.h"
 #include "qemu/option_int.h"
 
@@ -1594,7 +1595,7 @@ static int preallocate(BlockDriverState *bs)
 
 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, int prealloc,
+                         int flags, size_t cluster_size, PreallocMode prealloc,
                          QemuOpts *opts, int version,
                          Error **errp)
 {
@@ -1771,7 +1772,7 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
     uint64_t size = 0;
     int flags = 0;
     size_t cluster_size = DEFAULT_CLUSTER_SIZE;
-    int prealloc = 0;
+    PreallocMode prealloc = PREALLOC_MODE_OFF;
     int version = 3;
     Error *local_err = NULL;
     int ret;
@@ -1787,12 +1788,11 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
     cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
                                          DEFAULT_CLUSTER_SIZE);
     buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
-    if (!buf || !strcmp(buf, "off")) {
-        prealloc = 0;
-    } else if (!strcmp(buf, "metadata")) {
-        prealloc = 1;
-    } else {
-        error_setg(errp, "Invalid preallocation mode: '%s'", buf);
+    prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
+                               PREALLOC_MODE_MAX, PREALLOC_MODE_OFF,
+                               &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
         ret = -EINVAL;
         goto finish;
     }
diff --git a/qapi/block-core.json b/qapi/block-core.json
index faf394c..ca8a938 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1585,3 +1585,20 @@
             'len'   : 'int',
             'offset': 'int',
             'speed' : 'int' } }
+
+# @PreallocMode
+#
+# Preallocation mode of QEMU image file
+#
+# @off: no preallocation
+# @metadata: preallocate only for metadata
+# @falloc: like @full preallocation but allocate disk space by
+#          posix_fallocate() rather than writing zeros.
+# @full: preallocate all data by writing zeros to device to ensure disk
+#        space is really available. @full preallocation also sets up
+#        metadata correctly.
+#
+# Since 2.2
+##
+{ 'enum': 'PreallocMode',
+  'data': [ 'off', 'metadata', 'falloc', 'full' ] }
-- 
1.9.3

[Qemu-devel] [PATCH RFC v11 5/6] raw-posix: Add falloc and full preallocation option

[Hu Tao]

This patch adds a new option preallocation for raw format, and implements
falloc and full preallocation.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 block/raw-posix.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 55 insertions(+), 7 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 58c51d8..5dcd465 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -30,6 +30,7 @@
 #include "block/thread-pool.h"
 #include "qemu/iov.h"
 #include "raw-aio.h"
+#include "qapi/util.h"
 
 #if defined(__APPLE__) && (__MACH__)
 #include <paths.h>
@@ -1278,28 +1279,70 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
     int fd;
     int result = 0;
     int64_t total_size = 0;
+    PreallocMode prealloc = PREALLOC_MODE_OFF;
+    char *buf = NULL;
+    Error *local_err = NULL;
 
     strstart(filename, "file:", &filename);
 
     /* Read out options */
     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
                           BDRV_SECTOR_SIZE);
+    buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
+    prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
+                               PREALLOC_MODE_MAX, PREALLOC_MODE_OFF,
+                               &local_err);
+    g_free(buf);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        result = -EINVAL;
+        goto out;
+    }
 
     fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
                    0644);
     if (fd < 0) {
         result = -errno;
         error_setg_errno(errp, -result, "Could not create file");
-    } else {
-        if (ftruncate(fd, total_size) != 0) {
-            result = -errno;
-            error_setg_errno(errp, -result, "Could not resize file");
+        goto out;
+    }
+    if (ftruncate(fd, total_size) != 0) {
+        result = -errno;
+        error_setg_errno(errp, -result, "Could not resize file");
+        goto out_close;
+    }
+    if (prealloc == PREALLOC_MODE_FALLOC) {
+        /* posix_fallocate() doesn't set errno. */
+        result = -posix_fallocate(fd, 0, total_size);
+        if (result != 0) {
+            error_setg_errno(errp, -result,
+                             "Could not preallocate data for the new file");
         }
-        if (qemu_close(fd) != 0) {
-            result = -errno;
-            error_setg_errno(errp, -result, "Could not close the new file");
+    } else if (prealloc == PREALLOC_MODE_FULL) {
+        buf = g_malloc0(65536);
+        int64_t num = 0, left = total_size;
+
+        while (left > 0) {
+            num = MIN(left, 65536);
+            result = write(fd, buf, num);
+            if (result < 0) {
+                result = -errno;
+                error_setg_errno(errp, -result,
+                                 "Could not write to the new file");
+                g_free(buf);
+                goto out_close;
+            }
+            left -= num;
         }
+        fsync(fd);
+        g_free(buf);
+    }
+out_close:
+    if (qemu_close(fd) != 0 && result == 0) {
+        result = -errno;
+        error_setg_errno(errp, -result, "Could not close the new file");
     }
+out:
     return result;
 }
 
@@ -1477,6 +1520,11 @@ static QemuOptsList raw_create_opts = {
             .type = QEMU_OPT_SIZE,
             .help = "Virtual disk size"
         },
+        {
+            .name = BLOCK_OPT_PREALLOC,
+            .type = QEMU_OPT_STRING,
+            .help = "Preallocation mode (allowed values: off, falloc, full)"
+        },
         { /* end of list */ }
     }
 };
-- 
1.9.3

[Qemu-devel] [PATCH RFC v11 6/6] qcow2: Add falloc and full preallocation option

[Hu Tao]

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;
+        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
-- 
1.9.3

Re: [Qemu-devel] [PATCH for-2.1? RFC v11 1/6] block: round up file size to nearest sector

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 907 bytes --]

On 07/02/2014 02:17 AM, Hu Tao wrote:
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>  block/qcow2.c              |  3 ++-
>  block/raw-posix.c          |  4 +--
>  block/raw-win32.c          |  4 +--
>  tests/qemu-iotests/096     | 64 ++++++++++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/096.out | 14 ++++++++++
>  tests/qemu-iotests/group   |  1 +
>  6 files changed, 85 insertions(+), 5 deletions(-)
>  create mode 100755 tests/qemu-iotests/096
>  create mode 100644 tests/qemu-iotests/096.out

I think this patch qualifies as a bug fix; would you like to separate it
out, remove the RFC, and tag it for 2.1, so that it isn't held up by the
rest of the series?

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH RFC v11 4/6] qapi: introduce PreallocMode and a new PreallocMode full.

[Max Reitz]

On 02.07.2014 10:17, Hu Tao wrote:
> This patch prepares for the subsequent patches.
>
> Reviewed-by: Fam Zheng <famz@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>   block/qcow2.c        | 16 ++++++++--------
>   qapi/block-core.json | 17 +++++++++++++++++
>   2 files changed, 25 insertions(+), 8 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>

Re: [Qemu-devel] [PATCH RFC v11 5/6] raw-posix: Add falloc and full preallocation option

[Max Reitz]

On 02.07.2014 10:17, Hu Tao wrote:
> This patch adds a new option preallocation for raw format, and implements
> falloc and full preallocation.
>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>   block/raw-posix.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++-------
>   1 file changed, 55 insertions(+), 7 deletions(-)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 58c51d8..5dcd465 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -30,6 +30,7 @@
>   #include "block/thread-pool.h"
>   #include "qemu/iov.h"
>   #include "raw-aio.h"
> +#include "qapi/util.h"
>   
>   #if defined(__APPLE__) && (__MACH__)
>   #include <paths.h>
> @@ -1278,28 +1279,70 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
>       int fd;
>       int result = 0;
>       int64_t total_size = 0;
> +    PreallocMode prealloc = PREALLOC_MODE_OFF;
> +    char *buf = NULL;

It's not really necessary to initialize these two here, but it won't 
hurt either, of course (same thing later with num, which could have even 
been declared inside of the while loop).

Reviewed-by: Max Reitz <mreitz@redhat.com>

Re: [Qemu-devel] [PATCH RFC v11 2/6] raw, qcow2: don't convert file size to sector size

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 502 bytes --]

On 07/02/2014 02:17 AM, Hu Tao wrote:
> and avoid converting it back later.
> 
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>  block/qcow2.c     | 10 +++++-----
>  block/raw-posix.c |  6 +++---
>  block/raw-win32.c |  6 +++---
>  3 files changed, 11 insertions(+), 11 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH RFC v11 3/6] rename parse_enum_option to qapi_enum_parse and make it public

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 691 bytes --]

On 07/02/2014 02:17 AM, Hu Tao wrote:
> Suggested-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>  blockdev.c          | 30 ++++++------------------------
>  include/qapi/util.h | 17 +++++++++++++++++
>  qapi/Makefile.objs  |  1 +
>  qapi/qapi-util.c    | 32 ++++++++++++++++++++++++++++++++
>  4 files changed, 56 insertions(+), 24 deletions(-)
>  create mode 100644 include/qapi/util.h
>  create mode 100644 qapi/qapi-util.c

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH RFC v11 6/6] qcow2: Add falloc and full preallocation option

[Max Reitz]

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>

Re: [Qemu-devel] [PATCH RFC v11 6/6] qcow2: Add falloc and full preallocation option

[Max Reitz]

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