From 61a3061760caaaaa4f025f5712dcd8f84f2f5d70 Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Mon, 10 Nov 2014 09:14:06 +0100

Subject: [PATCH 29/41] raw-posix: Add falloc and full preallocation option

Message-id: <1415610847-15383-4-git-send-email-mreitz@redhat.com>

Patchwork-id: 62239

O-Subject: [RHEL-7.1 qemu-kvm PATCH v2 3/4] raw-posix: Add falloc and full preallocation option

Bugzilla: 1087724

RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

RH-Acked-by: Fam Zheng <famz@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

From: Hu Tao <hutao@cn.fujitsu.com>

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>

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

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit 06247428be8037b3739280f82cb29efe8397695f)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

Conflicts:

	block/raw-posix.c

QEMUOptionParameter has not been replaced with QemuOpts downstream

(upstream 6f482f742dd841b45297fb0e5f3d2c81779253be) and no "nocow"

downstream.

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

---

 block/raw-posix.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++------

 qemu-doc.texi     |  9 ++++++++

 qemu-img.texi     |  9 ++++++++

 3 files changed, 78 insertions(+), 7 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c

index 9ee5b8e..cfe7452 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>

@@ -1230,11 +1231,23 @@ static int raw_create(const char *filename, QEMUOptionParameter *options,

     int fd;

     int result = 0;

     int64_t total_size = 0;

+    PreallocMode prealloc = PREALLOC_MODE_OFF;

+    char *buf = NULL;

+    Error *local_err = NULL;

     /* Read out options */

     while (options && options->name) {

         if (!strcmp(options->name, BLOCK_OPT_SIZE)) {

             total_size = options->value.n / BDRV_SECTOR_SIZE;

+        } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) {

+            prealloc = qapi_enum_parse(PreallocMode_lookup, options->value.s,

+                                       PREALLOC_MODE_MAX, PREALLOC_MODE_OFF,

+                                       &local_err);

+            if (local_err) {

+                error_propagate(errp, local_err);

+                result = -EINVAL;

+                goto out;

+            }

         }

         options++;

     }

@@ -1244,16 +1257,51 @@ static int raw_create(const char *filename, QEMUOptionParameter *options,

     if (fd < 0) {

         result = -errno;

         error_setg_errno(errp, -result, "Could not create file");

-    } else {

-        if (ftruncate(fd, total_size * BDRV_SECTOR_SIZE) != 0) {

-            result = -errno;

-            error_setg_errno(errp, -result, "Could not resize file");

+        goto out;

+    }

+

+    if (ftruncate(fd, total_size * BDRV_SECTOR_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 * BDRV_SECTOR_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 * BDRV_SECTOR_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");

+                break;

+            }

+            left -= num;

         }

+        fsync(fd);

+        g_free(buf);

+    } else if (prealloc != PREALLOC_MODE_OFF) {

+        result = -EINVAL;

+        error_setg(errp, "Unsupported preallocation mode: %s",

+                   PreallocMode_lookup[prealloc]);

+    }

+

+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;

 }

@@ -1404,6 +1452,11 @@ static QEMUOptionParameter raw_create_options[] = {

         .type = OPT_SIZE,

         .help = "Virtual disk size"

     },

+    {

+        .name = BLOCK_OPT_PREALLOC,

+        .type = OPT_STRING,

+        .help = "Preallocation mode (allowed values: off, falloc, full)"

+    },

     { NULL }

 };

diff --git a/qemu-doc.texi b/qemu-doc.texi

index 54ab3c5..dc5b49e 100644

--- a/qemu-doc.texi

+++ b/qemu-doc.texi

@@ -527,6 +527,15 @@ Linux or NTFS on Windows), then only the written sectors will reserve

 space. Use @code{qemu-img info} to know the real size used by the

 image or @code{ls -ls} on Unix/Linux.

+Supported options:

+@table @code

+@item preallocation

+Preallocation mode (allowed values: @code{off}, @code{falloc}, @code{full}).

+@code{falloc} mode preallocates space for image by calling posix_fallocate().

+@code{full} mode preallocates space for image by writing zeros to underlying

+storage.

+@end table

+

 @item qcow2

 QEMU image format, the most versatile format. Use it to have smaller

 images (useful if your filesystem does not supports holes, for example

diff --git a/qemu-img.texi b/qemu-img.texi

index 5f99ebb..80d3261 100644

--- a/qemu-img.texi

+++ b/qemu-img.texi

@@ -392,6 +392,15 @@ Linux or NTFS on Windows), then only the written sectors will reserve

 space. Use @code{qemu-img info} to know the real size used by the

 image or @code{ls -ls} on Unix/Linux.

+Supported options:

+@table @code

+@item preallocation

+Preallocation mode (allowed values: @code{off}, @code{falloc}, @code{full}).

+@code{falloc} mode preallocates space for image by calling posix_fallocate().

+@code{full} mode preallocates space for image by writing zeros to underlying

+storage.

+@end table

+

 @item qcow2

 QEMU image format, the most versatile format. Use it to have smaller

 images (useful if your filesystem does not supports holes, for example

-- 

1.8.3.1