Commit 06247428 authored by Hu Tao's avatar Hu Tao Committed by Kevin Wolf
Browse files

raw-posix: Add falloc and full preallocation option 



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

Signed-off-by: default avatarHu Tao <hutao@cn.fujitsu.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent ffeaac9b

block/raw-posix.c

+73 −19
Original line number Diff line number Diff line
@@ -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>
@@ -1365,6 +1366,9 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp) 
    int result = 0;

    int64_t total_size = 0;

    bool nocow = false;

    PreallocMode prealloc;

    char *buf = NULL;

    Error *local_err = NULL;



    strstart(filename, "file:", &filename);
@@ -1372,13 +1376,25 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp) 
    total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),

                          BDRV_SECTOR_SIZE);

    nocow = qemu_opt_get_bool(opts, BLOCK_OPT_NOCOW, false);

    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 {

        goto out;

    }



    if (nocow) {

#ifdef __linux__

        /* Set NOCOW flag to solve performance issue on fs like btrfs.
@@ -1397,12 +1413,45 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp) 
    if (ftruncate(fd, total_size) != 0) {

        result = -errno;

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

        goto out_close;

    }

        if (qemu_close(fd) != 0) {



    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");

        }

    } 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 close the new file");

                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;

}
@@ -1585,6 +1634,11 @@ static QemuOptsList raw_create_opts = { 
            .type = QEMU_OPT_BOOL,

            .help = "Turn off copy-on-write (valid only on btrfs)"

        },

        {

            .name = BLOCK_OPT_PREALLOC,

            .type = QEMU_OPT_STRING,

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

        },

        { /* end of list */ }

    }

};

qemu-doc.texi

+9 −0
Original line number Diff line number Diff line
@@ -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

qemu-img.texi

+9 −0
Original line number Diff line number Diff line
@@ -419,6 +419,15 @@ 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