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/* libguestfs - the guestfsd daemon
* Copyright (C) 2014 Red Hat Inc.
*
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#ifdef HAVE_LINUX_FS_H
#include <linux/fs.h>
#endif
#include "daemon.h"
#include "actions.h"
#include "optgroups.h"
/* http://rwmj.wordpress.com/2014/03/11/blkdiscard-blkzeroout-blkdiscardzeroes-blksecdiscard/ */
#ifdef BLKDISCARD
int
optgroup_blkdiscard_available (void)
{
return 1;
}
int
do_blkdiscard (const char *device)
{
/* XXX We could read /sys/block/<device>/queue/discard_* in order to
* determine if discard is supported and the largest request size we
* are allowed to make. However:
*
* (1) Mapping the device name to /sys/block/<device> is quite hard
* (cf. the lv_canonical function in daemon/lvm.c)
*
* (2) We don't really need to do this in modern libguestfs since
* we're very likely to be using virtio-scsi, which supports
* arbitrary block discards.
*
* Let's wait to see if it causes a problem in real world
* situations.
*/
uint64_t range[2];
int64_t size;
int fd;
size = do_blockdev_getsize64 (device);
if (size == -1)
return -1;
range[0] = 0;
range[1] = (uint64_t) size;
fd = open (device, O_WRONLY|O_CLOEXEC);
if (fd == -1) {
reply_with_perror ("open: %s", device);
return -1;
}
if (ioctl (fd, BLKDISCARD, range) == -1) {
reply_with_perror ("ioctl: %s: BLKDISCARD", device);
close (fd);
return -1;
}
close (fd);
return 0;
}
#else /* !BLKDISCARD */
OPTGROUP_BLKDISCARD_NOT_AVAILABLE
#endif
#ifdef BLKDISCARDZEROES
int
optgroup_blkdiscardzeroes_available (void)
{
return 1;
}
int
do_blkdiscardzeroes (const char *device)
{
int fd;
unsigned int arg;
fd = open (device, O_RDONLY|O_CLOEXEC);
if (fd == -1) {
reply_with_perror ("open: %s", device);
return -1;
}
if (ioctl (fd, BLKDISCARDZEROES, &arg) == -1) {
reply_with_perror ("ioctl: %s: BLKDISCARDZEROES", device);
close (fd);
return -1;
}
close (fd);
return arg != 0;
}
#else /* !BLKDISCARDZEROES */
OPTGROUP_BLKDISCARDZEROES_NOT_AVAILABLE
#endif
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