Commit e6fd5d3a authored by Yuezhang Mo's avatar Yuezhang Mo Committed by Namjae Jeon
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exfat: support modifying mount options via remount 



Before this commit, all exfat-defined mount options could not be
modified dynamically via remount, and no error was returned.

After this commit, these three exfat-defined mount options
(discard, zero_size_dir, and errors) can be modified dynamically
via remount. While other exfat-defined mount options cannot be
modified dynamically via remount because their old settings are
cached in inodes or dentries, modifying them will be rejected with
an error.

Signed-off-by: default avatarYuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
parent 9fd68867

fs/exfat/super.c

+38 −6
Original line number Diff line number Diff line
@@ -243,11 +243,11 @@ static const struct fs_parameter_spec exfat_parameters[] = { 
	fsparam_u32oct("allow_utime",		Opt_allow_utime),

	fsparam_string("iocharset",		Opt_charset),

	fsparam_enum("errors",			Opt_errors, exfat_param_enums),

	fsparam_flag("discard",			Opt_discard),

	fsparam_flag_no("discard",		Opt_discard),

	fsparam_flag("keep_last_dots",		Opt_keep_last_dots),

	fsparam_flag("sys_tz",			Opt_sys_tz),

	fsparam_s32("time_offset",		Opt_time_offset),

	fsparam_flag("zero_size_dir",		Opt_zero_size_dir),

	fsparam_flag_no("zero_size_dir",	Opt_zero_size_dir),

	__fsparam(NULL, "utf8",			Opt_utf8, fs_param_deprecated,

		  NULL),

	__fsparam(NULL, "debug",		Opt_debug, fs_param_deprecated,
@@ -299,7 +299,7 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param) 
		opts->errors = result.uint_32;

		break;

	case Opt_discard:

		opts->discard = 1;

		opts->discard = !result.negated;

		break;

	case Opt_keep_last_dots:

		opts->keep_last_dots = 1;
@@ -317,7 +317,7 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param) 
		opts->time_offset = result.int_32;

		break;

	case Opt_zero_size_dir:

		opts->zero_size_dir = true;

		opts->zero_size_dir = !result.negated;

		break;

	case Opt_utf8:

	case Opt_debug:
@@ -742,12 +742,44 @@ static void exfat_free(struct fs_context *fc) 
static int exfat_reconfigure(struct fs_context *fc)

{

	struct super_block *sb = fc->root->d_sb;

	struct exfat_sb_info *remount_sbi = fc->s_fs_info;

	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	struct exfat_mount_options *new_opts = &remount_sbi->options;

	struct exfat_mount_options *cur_opts = &sbi->options;



	fc->sb_flags |= SB_NODIRATIME;



	sync_filesystem(sb);

	mutex_lock(&EXFAT_SB(sb)->s_lock);

	mutex_lock(&sbi->s_lock);

	exfat_clear_volume_dirty(sb);

	mutex_unlock(&EXFAT_SB(sb)->s_lock);

	mutex_unlock(&sbi->s_lock);



	if (new_opts->allow_utime == (unsigned short)-1)

		new_opts->allow_utime = ~new_opts->fs_dmask & 0022;



	/*

	 * Since the old settings of these mount options are cached in

	 * inodes or dentries, they cannot be modified dynamically.

	 */

	if (strcmp(new_opts->iocharset, cur_opts->iocharset) ||

	    new_opts->keep_last_dots != cur_opts->keep_last_dots ||

	    new_opts->sys_tz != cur_opts->sys_tz ||

	    new_opts->time_offset != cur_opts->time_offset ||

	    !uid_eq(new_opts->fs_uid, cur_opts->fs_uid) ||

	    !gid_eq(new_opts->fs_gid, cur_opts->fs_gid) ||

	    new_opts->fs_fmask != cur_opts->fs_fmask ||

	    new_opts->fs_dmask != cur_opts->fs_dmask ||

	    new_opts->allow_utime != cur_opts->allow_utime)

		return -EINVAL;



	if (new_opts->discard != cur_opts->discard &&

	    new_opts->discard &&

	    !bdev_max_discard_sectors(sb->s_bdev)) {

		exfat_warn(sb, "remounting with \"discard\" option, but the device does not support discard");

		return -EINVAL;

	}



	swap(*cur_opts, *new_opts);



	return 0;

}