Archipelago » qemu

# @guest-fstrim:

#

# Discard (or "trim") blocks which are not in use by the filesystem.

#

# @minimum:

#       Minimum contiguous free range to discard, in bytes. Free ranges

#       smaller than this may be ignored (this is a hint and the guest

#       may not respect it).  By increasing this value, the fstrim

#       operation will complete more quickly for filesystems with badly

#       fragmented free space, although not all blocks will be discarded.

#       The default value is zero, meaning "discard every free block".

#

# Returns: Nothing.

#

# Since: 1.2

##

{ 'command': 'guest-fstrim',

  'data': { '*minimum': 'int' } }

##

#ifdef FIFREEZE

#ifdef FITRIM

#define CONFIG_FSTRIM

#endif

#if defined(CONFIG_FSFREEZE) || defined(CONFIG_FSTRIM)

#endif

#if defined(CONFIG_FSFREEZE)

#if defined(CONFIG_FSTRIM)

/*

 * Walk list of mounted file systems in the guest, and trim them.

 */

void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **err)

{

    int ret = 0;

    FsMountList mounts;

    struct FsMount *mount;

    int fd;

    char err_msg[512];

    struct fstrim_range r = {

        .start = 0,

        .len = -1,

        .minlen = has_minimum ? minimum : 0,

    };

    slog("guest-fstrim called");

    QTAILQ_INIT(&mounts);

    ret = build_fs_mount_list(&mounts);

    if (ret < 0) {

        return;

    }

    QTAILQ_FOREACH(mount, &mounts, next) {

        fd = qemu_open(mount->dirname, O_RDONLY);

        if (fd == -1) {

            sprintf(err_msg, "failed to open %s, %s", mount->dirname,

                    strerror(errno));

            error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);

            goto error;

        }

        /* We try to cull filesytems we know won't work in advance, but other

         * filesytems may not implement fstrim for less obvious reasons.  These

         * will report EOPNOTSUPP; we simply ignore these errors.  Any other

         * error means an unexpected error, so return it in those cases.  In

         * some other cases ENOTTY will be reported (e.g. CD-ROMs).

         */

        ret = ioctl(fd, FITRIM, &r);

        if (ret == -1) {

            if (errno != ENOTTY && errno != EOPNOTSUPP) {

                sprintf(err_msg, "failed to trim %s, %s",

                        mount->dirname, strerror(errno));

                error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);

                close(fd);

                goto error;

            }

        }

        close(fd);

    }

error:

    free_fs_mount_list(&mounts);

}

#endif /* CONFIG_FSTRIM */

#endif /* CONFIG_FSFREEZE */

#if !defined(CONFIG_FSTRIM)

void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **err)

{

    error_set(err, QERR_UNSUPPORTED);

    return;

}

/*

 * Walk list of mounted file systems in the guest, and discard unused

 * areas.

 */

void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **err)

{

    error_set(err, QERR_UNSUPPORTED);

    return;

}